Title of Invention	DEVELOPER CARTRIDGE, DEVELOPING UNIT AND IMAGE FORMING APPARATUS HAVING THE SAME
Abstract	A developer cartridge includes a cartridge body comprising a developer discharge port, a remaining developer detecting unit arranged in the proximity to the developer discharge port, and an agitating unit rotatably arranged inside the cartridge body to convey the developer accommodated in the cartridge body toward the developer discharge port. Since the optical sensor provided in the image forming apparatus body is capable of physically measuring an exact amount of remaining sensor of the developer cartridge, a printing error due to erroneous determination of the remaining developer amount can be prevented.

Title of Invention

DEVELOPER CARTRIDGE, DEVELOPING UNIT AND IMAGE FORMING APPARATUS HAVING THE SAME

Abstract

A developer cartridge includes a cartridge body comprising a developer discharge port, a remaining developer detecting unit arranged in the proximity to the developer discharge port, and an agitating unit rotatably arranged inside the cartridge body to convey the developer accommodated in the cartridge body toward the developer discharge port. Since the optical sensor provided in the image forming apparatus body is capable of physically measuring an exact amount of remaining sensor of the developer cartridge, a printing error due to erroneous determination of the remaining developer amount can be prevented.

Full Text	FORM 2 THE PATENTS ACT, 1970 (39 of 1970) & The Patent Rules, 2003 COMPLETE SPECIFICATION 1. TITLE OF THE INVENTION: DEVELOPER CARTRIDGE, DEVELOPING UNIT AND IMAGE FORMING APPARATUS HAVING THE SAME 2. APPLICANT: Name: Samsung Electronics Co., Ltd. Nationality: Republic of Korea Address: 416, Maetan-dong, Yeongtong-gu, Suwon-si, Gyeon.ggi-do, Korea. 3. PREAMBLE TO THE DESCRIPTION: The following specification particularly describes the invention and the manner in which it is to be performed: CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority from Korean Patent Application No. 2008- 0016464, filed February 22. 2008, in the Korean Intellectual Property Office, the entire disclosure of which is hereby incorporated by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to an image forming apparatus, and more particularly to a developer cartridge capable of indicating the amount of remaining developer , and a developing unit and an image forming apparatus having the developer cartridge. 2. Description of the Related Art [0003] An image forming apparatus such as, e.g., an electrophotographic laser printer, generally uses a dry-type developer, such as a powered developer, to develop an image. The amount of remaining developer inside a developer cartridge is checked to control the developing system and also to alert the user when it is time to replace the cartridge. [0004] The powered developer is generally held in the developer cartridge, and typically requires an agitation in the developer cartridge. As the developer powder is caused to be moved around in the developer cartridge, sometimes resulting in a large amount of developer being moved to a particular location within the developer cartridge, it becomes difficult to measure with reasonable accuracy the amount of remaining developer in a developer cartridge when the measurement is taken from limited locations. [0005] A suggestion has been made to estimate the amount of the developer remaining, based on the amount of printing that had been performed. For example, a devoted control unit 2 may be provided to calculates an area of an electrostatic latent image formed on a photosensitive medium to estimate the amount of developer required to develop the electrostatic latent image. That is, the control unit may estimate an amount of required developer to print out one sheet of printing medium, and may keep track of an estimate of the amount of developer that may have been used, and thus estimates the amount of developer that may be remaining in the developer cartridge. [0006] However, since the above method is based on an indirect estimation, there often is a discrepancy between the estimate and the actual used amount. For example, the actual amount of remaining developer may generally turn out to be smaller than the estimated amount as some additional amount of developer may have been actually used due to, e.g., developer leakage, loss, or the like during printing operations. Such less than accurate estimate may result in images being printed with less density, or even failing to be printed. SUMMARY OF DISCLOSURE [0007] According to an aspect of the present disclosure, a developer cartridge may comprise: a cartridge body comprising a developer discharge port; a remaining developer detecting unit arranged in proximity of the developer discharge port; and an agitating unit rotatably arranged inside the cartridge body to convey the developer accommodated in the cartridge body toward the developer discharge port. [0008] The remaining developer detecting unit is arranged above the developer discharge port. [0009] The remaining developer detecting unit may comprise a first optical guide comprising a light entry portion arranged on one end to face a light emitting unit of an optical 3 sensor arranged on a main body of an image forming apparatus, and a first light transfer surface formed on the other end; and a second optical guide comprising a light exit portion arranged on one end to face a light receiving unit of the optical sensor, and a second light transfer surface formed on the other end. The first and second light transfer surfaces may be arranged to face each other at a predetermined distance from each other. [0010] The light entry portion and the light exit portion may be arranged in a co-planar relation with each other, so that a first optical path in which a light beam enters the light entry portion and a second optical path in which the light beam exits the light exit portion are parallel to each other. [0011] The first optical guide may comprise one or more first reflective surface to reflect the light beam emitted from the light emitting unit towards the second light transfer surface via the first light transfer surface. The second optical guide may comprise one or more second reflective surface to reflect the light beam received at the second light transfer surface towards the light exit portion. [0012] An angle of incidence and an angle of reflection of the light of the first and second reflective surfaces may be at 45° from each other. [0013] The developer cartridge may further include a cleaning unit interposed between the first and second light transfer surfaces, to wipe the first and second light transfer surfaces. [0014] The cleaning unit may be made to rotate together with the agitating unit. [0015] The cleaning unit may comprise a rotating axis that rotate together with the agitating unit; and a cleaning member arranged on the rotating axis to wipe the first and second light transfer surfaces in a rotating motion. 4 [0016] The cleaning member may rotate between a first position and a second position, in which the cleaning member in the first position is brought into contact with , and to thereby wipe, the first and second light transfer surfaces, (he cleaning member in the second position being away from the first and second light transfer surfaces so as not to interfere with an optical path of the light bean passing through the first and second light transfer surfaces. [0017] The first and second light transfer surfaces may be arranged above the developer discharge port. [0018] The surface of the light entry portion that faces the light emitting unit of the optical sensor and the surface of the light exit portion that faces the light receiving unit of the optical sensor may each be formed as a circular convex lens. [0019] The developer cartridge is detachably received into a developing cartridge of an image forming apparatus, the developer discharge port being formed at a bottom of the cartridge body, and in proximity of a front end with respect to a direction of inserting the cartridge body into the developing cartridge. [0020] According to another aspect, a developing unit may comprise a developing cartridge; and a developer cartridge removably received in the developing cartridge. The developer cartridge may comprise a developer discharge port, and a remaining developer detecting unit arranged in proximity of the developer discharge port, and an agitating unit rotatably arranged inside the developer cartridge to convey developer accommodated in the developer cartridge toward the developer discharge port. The developing cartridge may comprise a sensor hole formed to face the remaining developer detecting unit so that the remaining developer detecting unit is exposed through the sensor hole. 5 [0021] The remaining developer detecting unit may be made from a light permitting material, and arranged above th+e developer discharge port formed on the bottom of the developer cartridge. [0022] The remaining developer detecting unit may comprise a first optical guide comprising a light entry portion arranged on one end to face a light emitting unit of an optical sensor arranged on a main body of an image forming apparatus, and a first light transfer surface formed on the other end; and a second optical guide comprising a light exit portion arranged on one end to face a light receiving unit of the optical sensor, and a second light transfer surface formed on the other end. The light entry portion and the light exit portion may be arranged in a co-planar relation with each other, so that optical paths in which a light beam enters the light entry portion, and in which the light beam exits the light exit portion are parallel to each other. The first and second light transfer surfaces may be arranged to face each other at a predetermined distance from each other. [0023] The first optical guide may comprise one or more first reflective surface to reflect the light beam emitted from the light emitting unit towards the second light transfer surface via the first light transfer surface. The second optical guide may comprise one or more second reflective surface to reflect the light beam received at the second light transfer surface towards the light exit portion. An angle of incidence and an angle of reflection of the light of the first and second reflective surfaces may be at 45° from each other. [0024] According to yet another aspect, an image forming apparatus may comprise a main body comprising an optical sensor comprising a light emitting unit and a light receiving unit to detect an amount of remaining developer; a developing cartridge removably received in 6 the main body, the developing cartridge comprising a sensor hole formed to face the optical sensor; and a developer cartridge removably received in the developing cartridge. The developer cartridge may comprise a developer discharge port, a remaining developer detecting unit arranged, in a position proximate to the developer discharge port, and to face the optical sensor through the sensor hole when the developer cartridge is received in the developing cartridge, and an agitating unit rotatably arranged inside the developer cartridge to convey the developer accommodated in the cartridge body toward the developer discharge port. [0025] According to even yet another aspect, a developer cartridge may comprise a cartridge body defining an inner volume for storing therein a quantity of developer, the cartridge body including a developer discharge port, through which the developer is discharged from the inner volume; a developer detecting unit disposed in the inner volume at a location proximate to the developer discharge port, the developer detecting unit being configured to detect the presence of developer in the vicinity of the developer discharge port; and an agitating unit rotatably arranged inside the cartridge body to move the developer accommodated in the inner volume toward the developer discharge port. [0026] The developer detecting unit may be disposed above the developer discharge port. [0027] The developer detecting unit may comprise a first optical guide comprising a light entry portion arranged on one end thereof to receive light from a light emitting unit of an optical sensor and a first light transfer surface formed on the other end of the first optical guide; and a second optical guide comprising a second light transfer surface formed on one end thereof, the second light transfer surface being spaced apart from, and facing, the first light transfer surface, 7 and a light exit portion formed on the other end of the second optical guide to face a light receiving unit of the optical sensor. [0028] The light entry portion and the light exit portion may he arranged to he on a common plane so that the first optical path along which a light beam enters the light entry portion and the second optical path along which the light beam exits the light exit portion are parallel to each other. [0029] The first optical guide may comprise one or more first reflective surfaces connecting, and thereby defining a first optical path between, the light entry portion and the first light transfer surface, the one or more first reflective surfaces reflecting the light received through the light entry portion toward the first light transfer surface. The second optical guide may comprise one or more second reflective surfaces connecting the second light transfer surface and the light exit portion, the one or more second reflective surfaces reflecting the light received through the second light transfer surface toward the light exit portion to form a second optical path between the second light transfer surface and the light exit portion. [0030] Each of an angle of incidence and an angle of reflection of the light of each of the one or more first reflective surfaces and the one or more second reflective surface may be 45 ° . [0031] The developer cartridge may further comprise a cleaning member disposed in the cartridge body, the cleaning member being capable of being interposed between the first and second light transfer surfaces to wipe the developer off the first and second light transfer surfaces. [0032] The cleaning member may rotate about an rotational axis of the agitating unit between a first position and a second position, the cleaning member in the first position being brought into contact with the first and second light transfer surfaces, the cleaning member in the 8 second position being away from the first and second light transfer surfaces so as not to interfere with the optical path of the light between the first and second ljght transfer surfaces. [0033] Each of the light entry portion and the light exit portions may be formed as a circular convex lens. [0034] The developer detecting unit may farther comprise a light source disposed on the cartridge body and positioned so that the light source transmits the light to the light entry portion; and a light sensor disposed on the cartridge body and positioned so that the light sensor receives the light from the light exit portion. [0035] According to another aspect, a developing unit may comprise a developing cartridge body; a developer feeding unit disposed in the developing cartridge body, the developer feeding unit being configured to feed developer to a photosensitive medium for developing a latent image formed on the photosensitive medium; a developer storage chamber for storing therein a quantity of the developer, the developer storage chamber including a developer discharge port, through which the developer is discharged from the developer storage chamber to the developer feeding unit; a developer detecting unit disposed in the developer storage chamber at a location proximate to the developer discharge port, the developer detecting unit being configured to detect the presence of the developer in the vicinity of the developer discharge port; and an agitating unit rotatably arranged inside the developer storage chamber to move the developer accommodated in the developer storage chamber toward the developer discharge port. [0036] The developer detecting unit may comprise a first optical guide comprising a light entry portion arranged on one end thereof to receive light froin a light emitting unit of an optical sensor and a first light transfer surface formed on the other end of the first optical guide; and a 9 second optical guide comprising a second light transfer surface formed on one end thereof, the second light transfer surface being spaced apart from, and facing, the first light transfer surface, and a light exit portion formed on the other end of the second optical guide to face a light receiving unit of the optical sensor. [0037] The light entry portion and the light exit portion may be arranged to be on a common plane so that the first optical path along which a light beam enters the light entry portion and the second optical path along which the light beam exits the light exit portion are parallel to each other. [0038] The first optical guide may comprise one or more first reflective surfaces connecting, and thereby defining a first optical path between, the light entry portion and the first light transfer surface, the one or more first reflective surfaces reflecting the light received through the light entry portion toward the first light transfer surface. The second optical guide comprises one or more second reflective surfaces connecting the second light transfer surface and the light exit portion, the one or more second reflective surfaces reflecting the light received through the second Hght transfer surface toward the light exit portion to form a second optical path between the second light transfer surface and the light exit portion. [0039] Each of an angle of incidence and an angle of reflection of the light of each of the one or more first reflective surfaces and the one or more second reflective surface may be 45 ° . [0040] The developing unit may further comprise a cleaning member disposed in the developer storage chamber, the cleaning member being capable of being interposed between the first and second light transfer surfaces to wipe the developer off the first and second light transfer surfaces. 10 DETAILED DESCRIPTION OF SEVERAL EMBODIMENTS [0056] In the following description, the same drawing reference numerals are used for the same elements in a!l drawings. The matters defined in the description, such as detailed construction and elements, are provided to assist in a comprehensive understanding of the invention. Thus, it should be apparent that the exemplary embodiments of the invention can be carried out without those specifically detailed matters. Also, well-known functions or constructions are not described in detail so as to avoid obscuring the description with unnecessary detail. [0057] Referring to FIG. 1, a developing unit 200 may initially contain developer in a developing cartridge 210 when shipped. In one embodiment the developing cartridge 210 has a mounting cavity 213 (FIG. 2), and the opening of the mounting cavity 213 may be sealed with a dummy cover 250. When a user wishes to refill the developing unit 200 with developer, the dummy cover 250 may be removed, and a replacement developer cartridge 100 may be installed in the mounting cavity 213 to replenish the developer. An example of the replacement operation is illustrated in FIG. 2 while the developing unit 200 is shown with developer cartridge 100 installed in FIG. 3. [0058] Referring to FIG. 4, the developer cartridge 100 according to an embodiment of the invention may include a cartridge body 110 and a remaining developer detecting unit 120. The cartridge body 110 may include a developer discharge port 111 formed on the bottom adjacent to a front end of the cartridge body 110, where the front end may be, e.g., the end of the cartridge body 110 inserted first into the developing unit 200 during installation (see FIG. 2). The developer discharge port 111 may alternatively be disposed in a different location on the 13 cartridge body 110. The cartridge body 110 contains developer and may also house an agitating unit 112 to agitate and/or to convey the developer. [0059] In one embodiment of the invention, the remaning developer detecting unit 120 may be arranged directly above the developer discharge port 111. Other embodiments may allow the remaining developer discharge unit 120 to be located in another area within the cartridge body 110. The remaining developer detecting unit 120 may be made from a light permitting material to guide a path of light. As seen in FIG. 8, the light path may be an optical path between a light emitting unit 12a and a light receiving unit 12b of an optical sensor 12 formed on a body 10 of an image forming apparatus. Alternatively, light may be sourced by a light emitting unit disposed on the cartridge body 110 itself or the developing cartridge 210, or it may come from another source at a different location within the image forming apparatus. [0060] FIG. 5 is provided to explain an operational principle of the remaining developer detecting unit 120 (see FIG. 4) according to an embodiment of the invention. The remaining developer detecting unit 120 includes a first optical guide l21 and a second optical guide 122. The first optical guide 121 includes a light entry portion 121aformed on one end to face a light source, e.g., the light emitting unit 12a of the optical sensor 12, and a first light transfer surface 121b formed on the other end. A first reflective surface 121c is arranged on an optical path between the light entry portion 121aand the first light transfer surface 121b. [0061] The second optical guide 122 includes a light exit portion 122a formed on one end to face a light sensor, e.g., the light receiving unit 12b of the Optical sensor 12, and a second light transfer surface 122b formed on the other end. A second reflective surface 122c may be 14 arranged on an optical path between the light exit portion 122a and the second light transfer surface 122b. [0062] The light entry portion 121a and the light exit portion 122a may be arranged in a co-planar relation, so that parallel optical paths can be formed to pass the light to enter or exit the light entry portion 121a and the light exit portion 122a. The first and second light transfer surfaces 121b and 122b may be arranged to face each other at a predetermined distance. The first and second light transfer surfaces 121b and 122b may desirably be arranged directly above the developer discharge port 111 to measure the amount of remaining developer. [0063] The first and second reflective surfaces 121c and 122c may be arranged to cause the light entry portion 121a and the light exit portion 122a to be oriented in a co-planar relation. The first reflective surface 121c reflects a light toward the second light transfer surface 122b via the first light transfer surface 121b, and the second reflective surface 122c reflects the light received at the second light transfer surface 122b toward the light exit portion 122a. In one embodiment of the invention, the first and second light reflective surfaces 121c and 122c may be arranged so that the angle at which the light enters is at 45° from the angle at which the light is reflected. Two or more first and second reflective surfaces 121c and 122c may also be employed in alternate embodiments of the invention. [0064] For example. FIG. 6 illustrates an embodiment in which two first reflective surfaces 121c and two second reflective surfaces 122c are employed, thereby forming the optical paths indicated by the arrows. [0065] Referring to FIG. 6, in one embodiment of the invention, a cleaning unit 130 may be employed between the first and second light transfer surfaces 121b and 122b to clean the 15 facing surfaces of the first and second light transfer surfaces 121b and 122b. The cleaning unit 130 is rotatably arranged inside the cartridge body 110 to rotate about the shaft of the agitating unit 112, which rotates to agitate and/or convey the developer of the cartridge body 110 toward the developer discharge port 111. [0066] The cleaning unit 130 may include a rotating axis 131 and a cleaning member 132. Referring to FIG. 6, the rotating axis 131 utilizes the rotating axis of the agitating unit 112. Alternatively the rotating axis 131 may be arranged to rotate along its own axis. The cleaning member 132 may be rotated to wipe the facing surfaces of the first and second light transfer surfaces 121b and 122b concurrently, or in the alternative, in an alternating manner. The cleaning member 132 may be made from, e.g., urethane material, silicon rubber, sponge-type foam, films such as polyethylene terephthalate (PET) sheets, or other appropriate material. [0067] The cleaning member 132 may be rotated between a first position and a second position, in which the cleaning member 132 in the first position is brought into contact with the facing surfaces of the first and second light transfer surfaces 121b and 122b to wipe out the facing surfaces, and the cleaning member 132 in the second position is positioned away from the the first and second light transfer surfaces 121b and 122b so as not to interfere with the optical path of the light passing through the first and second light transfer surfaces 121b and 122b. [0068] In one embodiment of the invention, the surface of the light entry portion 121a that faces the light source (such as the light emitting unit 12a of the optical sensor 12) and the surface of the light exit portion 122a that faces the light receiving unit (such as the light receiving unit 12b of the optical sensor 12), may be formed as circular convex lenses in order to improve the sensitivity. 16 [0069] Referring to FIG. 7, the developing unit 200 according to an embodiment of the present invention may include a developing cartridge 210, and a developer, cartridge 100, which is configured in the manner explained above, and which may be removably received in the developing cartridge 210 as shown in FIG. 2. [0070] The developing cartridge 210 may include a photosensitive medium 211, a developer feeding unit 212 to feed the developer to the photosensitive medium 211, and a cartridge receiving recess 213 (FIG. 2) in which the developer cartridge 100 is removably received. In one embodiment of the invention, the developing cartridge 210 may include a sensor hole 215 (FIGS. 1 and 2) formed on a location to correspond to the remaining developer detecting unit 120 of the developer cartridge 100. According to an embodiment, the sensor hole 215 may be arranged in a circular configuration having the same diameter as the light entry portion 121a and the light exit portion 122a. [0071] Referring to FIG. 8, according to an embodiment of the invention, an optical sensor 12 may be installed in a main body 11 of an image forming apparatus 10. A developing unit 200, which is constructed in the manner explained above, may be removably received in the main body 11. The direction B in which the developer cartridge 100 is received in the developing unit 200 and removed from the developing unit 200 is in perpendicular relation to the direction A in which the developing unit 200 is received in the image forming apparatus 10 and removed from the image forming apparatus 10. [0072] For the sake of brevity, only the relevant portions of the image forming apparatus 10 and the developing unit 200 will be explained in detail below. 17 [0073] Referring to FIG. 1, the developing unit 200 is installed in the cartridge receiving recess 213 (FIG. 2), and the opening of the cartridge receiving recess 213 is sealed with the dummy cover 250, for example when the image forming apparatus is shipped from the factory. Printing may still be carried out using the developer contained within the developer feeding unit 212 (FIG. 7), which may hold an initial supply of developer, for example, sufficient amount for printing, e.g., approximately thousand sheets of paper. When a user wishes to replenish the developer supply, the user may remove the dummy cover 250 to insert a replacement developer cartridge 100 in the cartridge receiving recess 213 (FIG. 2). [0074] In one embodiment of the invention, when the developer cartridge 100 is inserted in the cartridge receiving recess 213, the optical sensor 12, arranged inside the image forming apparatus 10, faces the remaining developer detecting unit 120 through the sensor hole 215, so that the light emitting unit 12a of the optical sensor 12 faces the first optical guide 121, and the light receiving unit 12b of the optical sensor 12 faces the second optical guide 122. In alternative embodiments of the invention, an optical sensor may be disposed in place of the sensor hole 215 on the developing unit 200, or an optical sensor may be disposed on the developer cartridge 100 facing the first optical guide 121 and the second optical guide 122. [0075] When the developer cartridge 100 is installed within the cartridge receiving recess 213, the developer discharge port 111 is open, and a developer inlet port (not shown) of the developing unit 200 is also open. As a result, the developer of the developer cartridge 100 is fed into the developer feeding unit 212 of the developing unit 200. [0076] In one embodiment of the invention, when the developing unit 200 housing the developer cartridge 100 is received in the image forming apparatus 10, the direction in which the 18 developer cartridge 100 is inserted in the developing unit 200 and removed from the developing unit 200 may be in perpendicular relation with respect to the direction in which the developing unit 200 is inserted in the image forming apparatus 10 and removed from the image forming apparatus 10. [0077] In one embodiment of the invention, a control unit (not shown) of the image forming apparatus 10 may cause a light beam to be emitted to the remaining developer detecting unit 120 using the optical sensor 12, to determine whether the developer of the developer cartridge 100 is used up. The light emitting unit 12a of the optical sensor 12 emits a light beam to the first optical guide 121, and the emitted light is transferred toward the second optical guide 122 selectively depending on the amount of remaining developer. [0078] For example, if the amount of remaining developer of the developer cartridge 100 is above a predetermined level, the developer fills up the space between the facing surfaces of the first and second light transfer surfaces 121b and 122b, thereby blocking light from passing from the first optical guide 121 to the second optical guide 122. As a result, in one embodiment of the invention the light receiving unit 12b of the optical sensor 12 fails to receive the light beam emitted from the light emitting unit 12a. In this situation, the optical sensor 12 emits a sensing signal to indicate that a sufficient amount of developer is remaining to the control unit of the image forming apparatus 10. Although, if a cleaning unit 130 is provided, the same may rotate, e.g., with the rotation of the agitating unit 112, thereby constantly wiping out the facing surfaces of the first and second light transfer surfaces 121b and 122b, the developer will quickly fill in the space between the first and second light transfer surfaces 121b and 122b to block the light beam from being passed from the first optical guide 121 to the second optical guide 122. 19 [0079] If the remaining developer in the developer cartridge 100 is substantially depleted, light emitted is passed through the optical entry portion 121a, and reflected against one of more first reflective surface 12)c to be emitted to the first light transfer surface \7 lb, and the reflected light is passed through the empty space, enters the second light transfer surface 122b, and reflected against the second reflective surface 122c. In one embodiment of the invention, the light moves towards the light receiving unit 12b of the optical sensor 12 through the optical exit portion 122a. As a result, the light receiving unit 12b senses the light beam emitted from the light emitting unit 12a, and the optical sensor 12 outputs a signal to the control unit of the image forming apparatus 10 to indicate that the developer of the developer cartridge 100 has been substantially depleted. [0080] Since, in an embodiment, the cleaning unit 130 continuously rotates along with the agitating unit 112 to wipe out the facing surfaces of the first and second light transfer surfaces 121b and 122b, the space between the first and second optical guides 121 and 122 is emptied when the developer is used up. Accordingly, the light passes from the first light transfer surface 121b to the second light transfer surface 122b. [0081] As explained above, from the fact that the light beam emitted to the first optical guide 121 is blocked from being transferred to the Second optical guide 122 in the presence of the developer, but is transferred to the second optical guide 122 in the absence of the developer, whether or not the developer remains in the developer cartridge 100 may be determined. To this end, according to an embodiment, the image forming apparatus 10 may include a controller (not shown), which may be, e.g., a microprocessor, a microcontroller or the like, that includes a CPU to execute one or more computer instructions, e.g., to receive signal(s) from the optical sensor 12, 20 to determine base on the received signal(s) whether sufficient amount of developer remains in the developer cartridge, and to control the image forming apparatus appropriately, e.g., to alert the user that replenishment of developer is needed, and may further include a memory device, e.g., a Random Access Memory (RAM), Read-Only-Memory (ROM), a flesh memory, or the like, to store the one or more computer instructions. [0082] In one embodiment of the invention the first and second light transfer surfaces 121b and 122b may be arranged in the proximity to the developer discharge port 111. For example, the first and second light transfer surfaces 121b and 122b may be arranged directly above the developer discharge port 111, as illustrated in FIG. 4. The space between the first and second light transfer surfaces 121b and 122b is detected most accurately when the first and second light transfer surfaces 121b and 122b are arranged as close as possible to the developer discharge port 111. If the first and second light transfer surfaces 121b and 122b are arranged away from the developer discharge port 111, the optical sensor 12 may erroneously determine that the developer is used up while there is still developer inside the developer cartridge 100. However, if other design considerations make placement of the first and second light transfer surfaces 121band 122b away from the developer discharge port 111 desirable, the invention may still be practiced in such a design. [0083] According to one aspect of the invention, the optical sensor 12 may detect the amount of the remaining developer of the developer cartridge 100 as well as the presence/absence of the developer. As the developer recedes over time, the developer ripples, particularly at the areas contacting the ends of the first and second optical guides 121 and 122, while being conveyed toward the developer discharge port 111 due to the movement of the 21 agitating unit 112. As the developer ripples, the space between the first and second optical transfer surfaces 121b and 122b is occasionally emptied, thereby intermittently passing the light beam from the first optical guide 121 towards the second optical guide 122. As a result, the light receiving unit 12b of the optical sensor 12 may receive the light beam from the light emitting unit 12a. [0084] The relation between the amount of remaining developer and the number of occasions that the light beam passing the first optical guide 121 reaches the second optical guide 122, can be defined. For example, if it is established according to an embodiment of the invention, that the light beam passing the first optical guide 121 arrives at the second optical guide 122 two times per second when the remaining developer amount is approximately 50% of the full level, the optical sensor 12 may determine that the amount of the remaining developer is 50% of the full level based on the fact that the optical sensor 12 detects the light beam from the light emitting unit 12a arriving at the light receiving unit 12b two times per second. Other embodiments may have different relations between remaining developer and number of times the light beam travels through the remaining developer detecting unit 120, and the 50% full at two times per second relationship is only disclosed as an example. By storing a database of the sensed signals of the optical sensor 12 according to different levels of the developer, the amount of remaining developer inside the developer cartridge 100 can be determined. [0085] While an embodiment of the invention employs the optical sensor 12 to detect the amount of the remaining developer, it should be understood that the main object of the present invention is to provide a sensor to detect the amount of remaining developer in the developer cartridge 110. 22 [0086] Accordingly, not only the optical sensor 12. but also other types of sensors that can detect the developer amount can be employed. For example, a piezo sensor may be arranged in the proximity to the developer discharge port to measure the amount of remaining developer based on the weight and vibration of the developer. Alternatively, considering that the developer is generally a conductive material, a capacitance type sensor may be employed, in which a plurality of electrodes are arranged near the developer to detect the electric current flowing the electrodes or the difference of the voltages. A sensor to physically detect the amount of the remaining developer may also be arranged. [0087] The foregoing embodiments and advantages are merely examples and are not to be construed as limiting the present invention. The present teaching can be readily applied to various other embodiments. Also, the description of the embodiments of the present invention is intended to be illustrative, and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art. 23 We claim: 1. A developer cartridge, comprising: a cartridge body comprising a developer discharge port; a remaining developer detecting unit arranged in proximity of the developer discharge port; and an agitating unit rotatably arranged inside the cartridge body to convey the developer accommodated in the cartridge body toward the developer discharge port. 2. The developer cartridge of claim 1, wherein the remaining developer detecting unit is arranged above the developer discharge port. 3. The developer cartridge of claim 1, wherein the remaining developer detecting unit comprises: a first optical guide comprising a light entry portion arranged on one end to face a light emitting unit of an optical sensor arranged on a main body of an image forming apparatus, and a first light transfer surface formed on the other end; and a second optical guide comprising a light exit portion arranged on one end to face a light receiving unit of the optical sensor, and a second light transfer surface formed on the other end, wherein the first and second light transfer surfaces are arranged to face each other at a predetermined distance from each other. 24 4. The developer cartridge of claim 3. wherein the light entry portion and the light exit portion are arranged in a co-planar relation with each other, so that a first optical path in which a light beam enters the light entry portion and a second optical path in which the light beam exits the light exit portion are parallel to each other. 5. The developer cartridge of claim 4, wherein the first optical guide comprises one or more first reflective surface to reflect the light beam emitted from the light emitting unit towards the second light transfer surface via the first light transfer surface, and the second optical guide comprises one or more second reflective surface to reflect the light beam received at the second light transfer surface towards the light exit portion. 6. The developer cartridge of claim 5, wherein an angle of incidence and an angle of reflection of the light of the first and second reflective surfaces are at 45° from each other. 7. The developer cartridge of claim 3, further comprising a cleaning unit interposed between the first and second light transfer surfaces, to wipe the first and second light transfer surfaces. 8. The developer cartridge of claim 7, wherein the cleaning unit is rotated together with the agitating unit. 9. The developer cartridge of claim 7, wherein the cleaning unit comprises: 25 a rotating axis that rotate together with the agitating unit; and a cleaning member arranged on the rotating axis to wipe the first and second light transfer surfaces in a rotating motion. 10. The developer cartridge of claim 9, wherein the cleaning member is rotated between a first position and a second position, in which the cleaning member in the first position is brought into contact with , and to thereby wipe, the first and second light transfer surfaces, the cleaning member in the second position being away from the first and second light transfer surfaces so as not to interfere with an optical path of the light bean passing through the first and second light transfer surfaces. 11. The developer cartridge of claim 3, wherein the first and second light transfer surfaces are arranged above the developer discharge port. 12. The developer cartridge of claim 3, wherein the surface of the light entry portion that faces the light emitting unit of the optical sensor and the surface of the light exit portion that faces the light receiving unit of the optical sensor are each formed as a circular convex lens. 13. The developer cartridge of claim 1, wherein the developer cartridge is detachably received into a developing cartridge of an image forming apparatus, the developer discharge 26 port being formed at a bottom of the cartridge body, and in proximity of a front end with respect to a direction of inserting the cartridge body into the developing cartridge. 14. A developing unit, comprising: a developing cartridge; and a developer cartridge removably received in the developing cartridge, the developer cartridge comprising, a developer discharge port, and a remaining developer detecting unit arranged in proximity of the developer discharge port, and an agitating unit rotatably arranged inside the developer cartridge to convey developer accommodated in the developer cartridge toward the developer discharge port, wherein the developing cartridge comprises a sensor hole formed to face the remaining developer detecting unit so that the remaining developer detecting unit is exposed through the sensor hole. 15. The developing unit of claim 14, wherein the remaining developer detecting unit is made from a light permitting material, and arranged above the developer discharge port formed on the bottom of the developer cartridge. 16. The developing unit of claim 15, wherein the remaining developer detecting unit comprises: 27 a first optical guide comprising a light entry portion arranged on one end to face a light emitting unit of an optical sensor arranged on a main body of an image forming apparatus, and a first light transfer surface formed on the other end; and a second optical guide comprising a light exit portion arranged on one end to face a light receiving unit of the optical sensor, and a second light transfer surface formed on the other end, wherein the light entry portion and the light exit portion are arranged in a co-planar relation with each other, so that optical paths in which a light beam enters the light entry portion, and in which the light beam exits the light exit portion are parallel to each other, and wherein the first and second light transfer surfaces are arranged to face each other at a predetermined distance from each other. 17. The developing unit of claim 16, wherein the first optical guide comprises one or more first reflective surface to reflect the light beam emitted from the light emitting unit towards the second light transfer surface via the first light transfer surface, and the second optical guide comprises one or more second reflective surface to reflect the light beam received at the second light transfer surface towards the light exit portion, and wherein an angle of incidence and an angle of reflection of the light of the first and second reflective surfaces are at 45° from each other. 18. An image forming apparatus, comprising: a main body comprising an optical sensor comprising a light emitting unit and a light receiving unit to detect an amount of remaining developer; 28 a developing cartridge removably received in the main body, the developing cartridge comprising a sensor hole formed to face the optical sensor; and a developer cartridge removably received in the developing cartridge, the developer cartridge comprising, a developer discharge port, a remaining developer detecting unit arranged, in a position proximate to the developer discharge port, and to face the optical sensor through the sensor hole when the developer cartridge is received in the developing cartridge, and an agitating unit rotatably arranged inside the developer cartridge to convey the developer accommodated in the cartridge body toward the developer discharge port. 19. A developer cartridge, comprising: a cartridge body defining an inner volume for storing therein a quantity of developer, the cartridge body including a developer discharge port, through which the developer is discharged from the inner volume; a developer detecting unit disposed in the inner volume at a location proximate to the developer discharge port, the developer detecting unit being configured to detect the presence of developer in the vicinity of the developer discharge port; and an agitating unit rotatably arranged inside the cartridge body to move the developer accommodated in the inner volume toward the developer discharge port. 20. The developer cartridge according to claim 19, wherein the developer detecting unit is disposed above the developer discharge port. 29 21. The developer cartridge according to claim 19, wherein the developer detecting unit comprises: a first optical guide comprising a light entry portion arranged on one end thereof to receive light from a light emitting unit of an optical sensor and a first light transfer surface formed on the other end of the first optical guide; and a second optical guide comprising a second light transfer surface formed on one end thereof, the second light transfer surface being spaced apart from, and facing, the first light transfer surface, and a light exit portion formed on the other end of the second optical guide to face a Tight receiving unit of the optical' sensor. 22. The developer cartridge according to claim 21, wherein the light entry portion and the light exit portion are arranged to be on a common plane so that the first optical path along which a light beam enters the light entry portion and the second optical path along which the light beam exits the light exit portion are parallel to each other. 23. The developer cartridge according to claim 21, wherein: the first optical guide comprises one or more first reflective surfaces connecting, and thereby defining a first optical path between, the light entry portion and the first light transfer surface, the one or more first reflective surfaces reflecting the light received through the light entry portion toward the first light transfer surface, and wherein the second optical guide comprises one or more second reflective surfaces connecting the second light transfer surface and the light exit portion, the one or more second reflective surfaces reflecting the light received through the second light transfer surface 30 a light source disposed on the cartridge body and positioned so that the light source transmits the light to the light entry portion; and a light sensor disposed on the cartridge body and positioned so that the light sensor receives the light from the light exit portion. 29. A developing unit, comprising: a developing cartridge body; a developer feeding unit disposed in the developing cartridge body, the developer feeding unit being configured to feed developer to a photosensitive medium for developing a latent image formed on the photosensitive medium; a developer storage chamber for storing therein a quantity of the developer, the developer storage chamber including a developer discharge port, through which the developer is discharged from the developer storage chamber to the developer feeding unit; a developer detecting unit disposed in the developer storage chamber at a location proximate to the developer discharge port, the developer detecting unit being configured to detect the presence of the developer in the vicinity of the developer discharge port; and an agitating unit rotatably arranged inside the developer storage chamber to move the developer accommodated in the developer storage chamber toward the developer discharge port. 30. The developing unit according to claim 29, wherein the developer detecting unit comprises: 32 a first optical guide comprising a light entry portion arranged on one end thereof to receive light from a light emitting unit of an optical sensor and a first light transfer surface formed on the other end of the first optical guide; and a second optical guide comprising a second light transfer surface formed on one end thereof, the second light transfer surface being spaced apart from, and facing, the first light transfer surface, and a light exit portion formed on the other end of the second optical guide to face a light receiving unit of the optical sensor. 31. The developing unit according to claim 30, wherein the light entry portion and the light exit portion are arranged to be on a common plane so that the first optical path along which a light beam enters the light entry portion and the second optical path along which the light beam exits the light exit portion are parallel to each other. 32. The developing unit according to claim 30, wherein: the first optical guide comprises one or more first reflective surfaces connecting, and thereby defining a first optical path between, the light entry portion and the first Ught transfer surface, the one or more first reflective surfaces reflecting the light received through the light entry portion toward the first light transfer surface, and wherein the second optical guide comprises one or more second reflective surfaces connecting the second light transfer surface and the light exit portion, the one or more second reflective surfaces reflecting the light received through the second light transfer surface toward the light exit portion to form a second optical path between the second light transfer surface and the light exit portion. 33 33. The developing unit according to claim 32, wherein each of an angle of incidence and an angle of reflection of the light of each of the one or more first reflective surfaces and the one or more second reflective surface is 45°. 34. The developing unit according to claim 30, further comprising: a cleaning member disposed in the developer storage chamber, the cleaning member being capable of being interposed between the first and second light transfer surfaces to wipe the developer off the first and second light transfer surfaces. 35. The developing unit according to claim 34, wherein: the cleaning member rotates about an rotational axis of the agitating unit between a first position and a second position, the cleaning member in the first position being brought into contact with the first and second light transfer surfaces, and the cleaning member in the second position being away from the first and second light transfer surfaces so as not to interfere with the optical path of the light between the first and second light transfer surfaces. 36. The developing unit according to claim 30, wherein the light entry portion and the light exit portions are arranged to be exposed outside the developing cartridge body. 37. The developing unit according to claim 30, wherein each of the light entry portion and the light exit portions is formed as a circular convex lens. 38. The developing unit according to claim 30, wherein the developer detecting unit further comprises: 34 a light source disposed on the developing cartridge body and positioned so that the light source transmits the light to the light entry portion; and a light sensor disposed on the developing cartridge body and positioned so that the light sensor receives the light from the light exit portion. , 39. The developing unit according to claim 30, wherein the developer storage chamber comprises a developer cartridge removably received in the developing unit, the developer cartridge being housed in a developer cartridge body, and wherein the light entry portion and the light exit portions are arranged to be exposed outside the developer cartridge body. 40. The developing unit according to claim 38, wherein the developer detecting unit further comprises: a light source disposed on the developer cartridge body and positioned so that the light source transmits the light to the light entry portion; and a light sensor disposed on the developer cartridge body and positioned so that the light sensor receives the light from the light exit portion. Dated this 29th day of September, 2008. 35

Full Text

FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
& The Patent Rules, 2003
COMPLETE SPECIFICATION
1. TITLE OF THE INVENTION:
DEVELOPER CARTRIDGE, DEVELOPING UNIT AND IMAGE FORMING APPARATUS HAVING THE SAME

2. APPLICANT:
Name: Samsung Electronics Co., Ltd.
Nationality: Republic of Korea
Address: 416, Maetan-dong, Yeongtong-gu, Suwon-si, Gyeon.ggi-do, Korea.

3. PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it is to be performed:

CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from Korean Patent Application No. 2008-
0016464, filed February 22. 2008, in the Korean Intellectual Property Office, the entire disclosure of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to an image forming apparatus, and more
particularly to a developer cartridge capable of indicating the amount of remaining developer , and a developing unit and an image forming apparatus having the developer cartridge.
2. Description of the Related Art
[0003] An image forming apparatus such as, e.g., an electrophotographic laser printer,
generally uses a dry-type developer, such as a powered developer, to develop an image. The amount of remaining developer inside a developer cartridge is checked to control the developing system and also to alert the user when it is time to replace the cartridge.
[0004] The powered developer is generally held in the developer cartridge, and typically
requires an agitation in the developer cartridge. As the developer powder is caused to be moved around in the developer cartridge, sometimes resulting in a large amount of developer being moved to a particular location within the developer cartridge, it becomes difficult to measure with reasonable accuracy the amount of remaining developer in a developer cartridge when the measurement is taken from limited locations.
[0005] A suggestion has been made to estimate the amount of the developer remaining,
based on the amount of printing that had been performed. For example, a devoted control unit
2

may be provided to calculates an area of an electrostatic latent image formed on a photosensitive medium to estimate the amount of developer required to develop the electrostatic latent image. That is, the control unit may estimate an amount of required developer to print out one sheet of printing medium, and may keep track of an estimate of the amount of developer that may have been used, and thus estimates the amount of developer that may be remaining in the developer cartridge.
[0006] However, since the above method is based on an indirect estimation, there often is
a discrepancy between the estimate and the actual used amount. For example, the actual amount of remaining developer may generally turn out to be smaller than the estimated amount as some additional amount of developer may have been actually used due to, e.g., developer leakage, loss, or the like during printing operations. Such less than accurate estimate may result in images being printed with less density, or even failing to be printed.
SUMMARY OF DISCLOSURE
[0007] According to an aspect of the present disclosure, a developer cartridge may
comprise: a cartridge body comprising a developer discharge port; a remaining developer
detecting unit arranged in proximity of the developer discharge port; and an agitating unit
rotatably arranged inside the cartridge body to convey the developer accommodated in the
cartridge body toward the developer discharge port.
[0008] The remaining developer detecting unit is arranged above the developer discharge
port.
[0009] The remaining developer detecting unit may comprise a first optical guide
comprising a light entry portion arranged on one end to face a light emitting unit of an optical
3

sensor arranged on a main body of an image forming apparatus, and a first light transfer surface
formed on the other end; and a second optical guide comprising a light exit portion arranged on
one end to face a light receiving unit of the optical sensor, and a second light transfer surface
formed on the other end. The first and second light transfer surfaces may be arranged to face
each other at a predetermined distance from each other.
[0010] The light entry portion and the light exit portion may be arranged in a co-planar
relation with each other, so that a first optical path in which a light beam enters the light entry
portion and a second optical path in which the light beam exits the light exit portion are parallel
to each other.
[0011] The first optical guide may comprise one or more first reflective surface to reflect
the light beam emitted from the light emitting unit towards the second light transfer surface via
the first light transfer surface. The second optical guide may comprise one or more second
reflective surface to reflect the light beam received at the second light transfer surface towards
the light exit portion.
[0012] An angle of incidence and an angle of reflection of the light of the first and
second reflective surfaces may be at 45° from each other.
[0013] The developer cartridge may further include a cleaning unit interposed between
the first and second light transfer surfaces, to wipe the first and second light transfer surfaces.
[0014] The cleaning unit may be made to rotate together with the agitating unit.
[0015] The cleaning unit may comprise a rotating axis that rotate together with the
agitating unit; and a cleaning member arranged on the rotating axis to wipe the first and second
light transfer surfaces in a rotating motion.
4

[0016] The cleaning member may rotate between a first position and a second position, in
which the cleaning member in the first position is brought into contact with , and to thereby wipe,
the first and second light transfer surfaces, (he cleaning member in the second position being
away from the first and second light transfer surfaces so as not to interfere with an optical path of
the light bean passing through the first and second light transfer surfaces.
[0017] The first and second light transfer surfaces may be arranged above the developer
discharge port.
[0018] The surface of the light entry portion that faces the light emitting unit of the
optical sensor and the surface of the light exit portion that faces the light receiving unit of the
optical sensor may each be formed as a circular convex lens.
[0019] The developer cartridge is detachably received into a developing cartridge of an
image forming apparatus, the developer discharge port being formed at a bottom of the cartridge
body, and in proximity of a front end with respect to a direction of inserting the cartridge body
into the developing cartridge.
[0020] According to another aspect, a developing unit may comprise a developing
cartridge; and a developer cartridge removably received in the developing cartridge. The
developer cartridge may comprise a developer discharge port, and a remaining developer
detecting unit arranged in proximity of the developer discharge port, and an agitating unit
rotatably arranged inside the developer cartridge to convey developer accommodated in the
developer cartridge toward the developer discharge port. The developing cartridge may
comprise a sensor hole formed to face the remaining developer detecting unit so that the
remaining developer detecting unit is exposed through the sensor hole.
5

[0021] The remaining developer detecting unit may be made from a light permitting
material, and arranged above th+e developer discharge port formed on the bottom of the developer cartridge.
[0022] The remaining developer detecting unit may comprise a first optical guide
comprising a light entry portion arranged on one end to face a light emitting unit of an optical sensor arranged on a main body of an image forming apparatus, and a first light transfer surface formed on the other end; and a second optical guide comprising a light exit portion arranged on one end to face a light receiving unit of the optical sensor, and a second light transfer surface formed on the other end. The light entry portion and the light exit portion may be arranged in a co-planar relation with each other, so that optical paths in which a light beam enters the light entry portion, and in which the light beam exits the light exit portion are parallel to each other. The first and second light transfer surfaces may be arranged to face each other at a predetermined distance from each other.
[0023] The first optical guide may comprise one or more first reflective surface to reflect
the light beam emitted from the light emitting unit towards the second light transfer surface via the first light transfer surface. The second optical guide may comprise one or more second reflective surface to reflect the light beam received at the second light transfer surface towards the light exit portion. An angle of incidence and an angle of reflection of the light of the first and second reflective surfaces may be at 45° from each other.
[0024] According to yet another aspect, an image forming apparatus may comprise a
main body comprising an optical sensor comprising a light emitting unit and a light receiving unit to detect an amount of remaining developer; a developing cartridge removably received in
6

the main body, the developing cartridge comprising a sensor hole formed to face the optical sensor; and a developer cartridge removably received in the developing cartridge. The developer cartridge may comprise a developer discharge port, a remaining developer detecting unit arranged, in a position proximate to the developer discharge port, and to face the optical sensor through the sensor hole when the developer cartridge is received in the developing cartridge, and an agitating unit rotatably arranged inside the developer cartridge to convey the developer accommodated in the cartridge body toward the developer discharge port.
[0025] According to even yet another aspect, a developer cartridge may comprise a
cartridge body defining an inner volume for storing therein a quantity of developer, the cartridge body including a developer discharge port, through which the developer is discharged from the inner volume; a developer detecting unit disposed in the inner volume at a location proximate to the developer discharge port, the developer detecting unit being configured to detect the presence of developer in the vicinity of the developer discharge port; and an agitating unit rotatably arranged inside the cartridge body to move the developer accommodated in the inner volume toward the developer discharge port.
[0026] The developer detecting unit may be disposed above the developer discharge port.
[0027] The developer detecting unit may comprise a first optical guide comprising a light
entry portion arranged on one end thereof to receive light from a light emitting unit of an optical sensor and a first light transfer surface formed on the other end of the first optical guide; and a second optical guide comprising a second light transfer surface formed on one end thereof, the second light transfer surface being spaced apart from, and facing, the first light transfer surface,
7

and a light exit portion formed on the other end of the second optical guide to face a light receiving unit of the optical sensor.
[0028] The light entry portion and the light exit portion may he arranged to he on a
common plane so that the first optical path along which a light beam enters the light entry portion and the second optical path along which the light beam exits the light exit portion are parallel to each other.
[0029] The first optical guide may comprise one or more first reflective surfaces
connecting, and thereby defining a first optical path between, the light entry portion and the first light transfer surface, the one or more first reflective surfaces reflecting the light received through the light entry portion toward the first light transfer surface. The second optical guide may comprise one or more second reflective surfaces connecting the second light transfer surface and the light exit portion, the one or more second reflective surfaces reflecting the light received through the second light transfer surface toward the light exit portion to form a second optical path between the second light transfer surface and the light exit portion.
[0030] Each of an angle of incidence and an angle of reflection of the light of each of the
one or more first reflective surfaces and the one or more second reflective surface may be 45 ° .
[0031] The developer cartridge may further comprise a cleaning member disposed in the
cartridge body, the cleaning member being capable of being interposed between the first and
second light transfer surfaces to wipe the developer off the first and second light transfer surfaces.
[0032] The cleaning member may rotate about an rotational axis of the agitating unit
between a first position and a second position, the cleaning member in the first position being brought into contact with the first and second light transfer surfaces, the cleaning member in the
8

second position being away from the first and second light transfer surfaces so as not to interfere
with the optical path of the light between the first and second ljght transfer surfaces.
[0033] Each of the light entry portion and the light exit portions may be formed as a
circular convex lens.
[0034] The developer detecting unit may farther comprise a light source disposed on the
cartridge body and positioned so that the light source transmits the light to the light entry portion;
and a light sensor disposed on the cartridge body and positioned so that the light sensor receives the light from the light exit portion.
[0035] According to another aspect, a developing unit may comprise a developing
cartridge body; a developer feeding unit disposed in the developing cartridge body, the developer
feeding unit being configured to feed developer to a photosensitive medium for developing a
latent image formed on the photosensitive medium; a developer storage chamber for storing
therein a quantity of the developer, the developer storage chamber including a developer
discharge port, through which the developer is discharged from the developer storage chamber to
the developer feeding unit; a developer detecting unit disposed in the developer storage chamber
at a location proximate to the developer discharge port, the developer detecting unit being
configured to detect the presence of the developer in the vicinity of the developer discharge port;
and an agitating unit rotatably arranged inside the developer storage chamber to move the
developer accommodated in the developer storage chamber toward the developer discharge port.
[0036] The developer detecting unit may comprise a first optical guide comprising a light
entry portion arranged on one end thereof to receive light froin a light emitting unit of an optical sensor and a first light transfer surface formed on the other end of the first optical guide; and a
9

second optical guide comprising a second light transfer surface formed on one end thereof, the second light transfer surface being spaced apart from, and facing, the first light transfer surface, and a light exit portion formed on the other end of the second optical guide to face a light receiving unit of the optical sensor.
[0037] The light entry portion and the light exit portion may be arranged to be on a
common plane so that the first optical path along which a light beam enters the light entry portion and the second optical path along which the light beam exits the light exit portion are parallel to each other.
[0038] The first optical guide may comprise one or more first reflective surfaces
connecting, and thereby defining a first optical path between, the light entry portion and the first light transfer surface, the one or more first reflective surfaces reflecting the light received through the light entry portion toward the first light transfer surface. The second optical guide comprises one or more second reflective surfaces connecting the second light transfer surface and the light exit portion, the one or more second reflective surfaces reflecting the light received through the second Hght transfer surface toward the light exit portion to form a second optical path between the second light transfer surface and the light exit portion.
[0039] Each of an angle of incidence and an angle of reflection of the light of each of the
one or more first reflective surfaces and the one or more second reflective surface may be 45 ° .
[0040] The developing unit may further comprise a cleaning member disposed in the
developer storage chamber, the cleaning member being capable of being interposed between the first and second light transfer surfaces to wipe the developer off the first and second light transfer surfaces.
10

DETAILED DESCRIPTION OF SEVERAL EMBODIMENTS
[0056] In the following description, the same drawing reference numerals are used for
the same elements in a!l drawings. The matters defined in the description, such as detailed construction and elements, are provided to assist in a comprehensive understanding of the invention. Thus, it should be apparent that the exemplary embodiments of the invention can be carried out without those specifically detailed matters. Also, well-known functions or constructions are not described in detail so as to avoid obscuring the description with unnecessary detail.
[0057] Referring to FIG. 1, a developing unit 200 may initially contain developer in a
developing cartridge 210 when shipped. In one embodiment the developing cartridge 210 has a mounting cavity 213 (FIG. 2), and the opening of the mounting cavity 213 may be sealed with a dummy cover 250. When a user wishes to refill the developing unit 200 with developer, the dummy cover 250 may be removed, and a replacement developer cartridge 100 may be installed in the mounting cavity 213 to replenish the developer. An example of the replacement operation is illustrated in FIG. 2 while the developing unit 200 is shown with developer cartridge 100 installed in FIG. 3.
[0058] Referring to FIG. 4, the developer cartridge 100 according to an embodiment of
the invention may include a cartridge body 110 and a remaining developer detecting unit 120. The cartridge body 110 may include a developer discharge port 111 formed on the bottom adjacent to a front end of the cartridge body 110, where the front end may be, e.g., the end of the cartridge body 110 inserted first into the developing unit 200 during installation (see FIG. 2). The developer discharge port 111 may alternatively be disposed in a different location on the
13

cartridge body 110. The cartridge body 110 contains developer and may also house an agitating unit 112 to agitate and/or to convey the developer.
[0059] In one embodiment of the invention, the remaning developer detecting unit 120
may be arranged directly above the developer discharge port 111. Other embodiments may
allow the remaining developer discharge unit 120 to be located in another area within the
cartridge body 110. The remaining developer detecting unit 120 may be made from a light
permitting material to guide a path of light. As seen in FIG. 8, the light path may be an optical
path between a light emitting unit 12a and a light receiving unit 12b of an optical sensor 12
formed on a body 10 of an image forming apparatus. Alternatively, light may be sourced by a
light emitting unit disposed on the cartridge body 110 itself or the developing cartridge 210, or it
may come from another source at a different location within the image forming apparatus.
[0060] FIG. 5 is provided to explain an operational principle of the remaining developer
detecting unit 120 (see FIG. 4) according to an embodiment of the invention. The remaining
developer detecting unit 120 includes a first optical guide l21 and a second optical guide 122.
The first optical guide 121 includes a light entry portion 121aformed on one end to face a light
source, e.g., the light emitting unit 12a of the optical sensor 12, and a first light transfer surface
121b formed on the other end. A first reflective surface 121c is arranged on an optical path
between the light entry portion 121aand the first light transfer surface 121b.
[0061] The second optical guide 122 includes a light exit portion 122a formed on one end
to face a light sensor, e.g., the light receiving unit 12b of the Optical sensor 12, and a second light transfer surface 122b formed on the other end. A second reflective surface 122c may be
14

arranged on an optical path between the light exit portion 122a and the second light transfer
surface 122b.
[0062] The light entry portion 121a and the light exit portion 122a may be arranged in a
co-planar relation, so that parallel optical paths can be formed to pass the light to enter or exit the
light entry portion 121a and the light exit portion 122a. The first and second light transfer
surfaces 121b and 122b may be arranged to face each other at a predetermined distance. The first
and second light transfer surfaces 121b and 122b may desirably be arranged directly above the
developer discharge port 111 to measure the amount of remaining developer.
[0063] The first and second reflective surfaces 121c and 122c may be arranged to cause
the light entry portion 121a and the light exit portion 122a to be oriented in a co-planar relation.
The first reflective surface 121c reflects a light toward the second light transfer surface 122b via
the first light transfer surface 121b, and the second reflective surface 122c reflects the light
received at the second light transfer surface 122b toward the light exit portion 122a. In one
embodiment of the invention, the first and second light reflective surfaces 121c and 122c may be
arranged so that the angle at which the light enters is at 45° from the angle at which the light is
reflected. Two or more first and second reflective surfaces 121c and 122c may also be employed
in alternate embodiments of the invention.
[0064] For example. FIG. 6 illustrates an embodiment in which two first reflective
surfaces 121c and two second reflective surfaces 122c are employed, thereby forming the optical
paths indicated by the arrows.
[0065] Referring to FIG. 6, in one embodiment of the invention, a cleaning unit 130 may
be employed between the first and second light transfer surfaces 121b and 122b to clean the
15

facing surfaces of the first and second light transfer surfaces 121b and 122b. The cleaning unit 130 is rotatably arranged inside the cartridge body 110 to rotate about the shaft of the agitating unit 112, which rotates to agitate and/or convey the developer of the cartridge body 110 toward the developer discharge port 111.
[0066] The cleaning unit 130 may include a rotating axis 131 and a cleaning member 132.
Referring to FIG. 6, the rotating axis 131 utilizes the rotating axis of the agitating unit 112.
Alternatively the rotating axis 131 may be arranged to rotate along its own axis. The cleaning
member 132 may be rotated to wipe the facing surfaces of the first and second light transfer
surfaces 121b and 122b concurrently, or in the alternative, in an alternating manner. The
cleaning member 132 may be made from, e.g., urethane material, silicon rubber, sponge-type
foam, films such as polyethylene terephthalate (PET) sheets, or other appropriate material.
[0067] The cleaning member 132 may be rotated between a first position and a second
position, in which the cleaning member 132 in the first position is brought into contact with the
facing surfaces of the first and second light transfer surfaces 121b and 122b to wipe out the
facing surfaces, and the cleaning member 132 in the second position is positioned away from the
the first and second light transfer surfaces 121b and 122b so as not to interfere with the optical
path of the light passing through the first and second light transfer surfaces 121b and 122b.
[0068] In one embodiment of the invention, the surface of the light entry portion 121a
that faces the light source (such as the light emitting unit 12a of the optical sensor 12) and the surface of the light exit portion 122a that faces the light receiving unit (such as the light receiving unit 12b of the optical sensor 12), may be formed as circular convex lenses in order to improve the sensitivity.
16

[0069] Referring to FIG. 7, the developing unit 200 according to an embodiment of the
present invention may include a developing cartridge 210, and a developer, cartridge 100, which is configured in the manner explained above, and which may be removably received in the developing cartridge 210 as shown in FIG. 2.
[0070] The developing cartridge 210 may include a photosensitive medium 211, a
developer feeding unit 212 to feed the developer to the photosensitive medium 211, and a cartridge receiving recess 213 (FIG. 2) in which the developer cartridge 100 is removably received. In one embodiment of the invention, the developing cartridge 210 may include a sensor hole 215 (FIGS. 1 and 2) formed on a location to correspond to the remaining developer detecting unit 120 of the developer cartridge 100. According to an embodiment, the sensor hole 215 may be arranged in a circular configuration having the same diameter as the light entry portion 121a and the light exit portion 122a.
[0071] Referring to FIG. 8, according to an embodiment of the invention, an optical
sensor 12 may be installed in a main body 11 of an image forming apparatus 10. A developing unit 200, which is constructed in the manner explained above, may be removably received in the main body 11. The direction B in which the developer cartridge 100 is received in the developing unit 200 and removed from the developing unit 200 is in perpendicular relation to the direction A in which the developing unit 200 is received in the image forming apparatus 10 and removed from the image forming apparatus 10.
[0072] For the sake of brevity, only the relevant portions of the image forming apparatus
10 and the developing unit 200 will be explained in detail below.
17

[0073] Referring to FIG. 1, the developing unit 200 is installed in the cartridge receiving
recess 213 (FIG. 2), and the opening of the cartridge receiving recess 213 is sealed with the dummy cover 250, for example when the image forming apparatus is shipped from the factory. Printing may still be carried out using the developer contained within the developer feeding unit 212 (FIG. 7), which may hold an initial supply of developer, for example, sufficient amount for printing, e.g., approximately thousand sheets of paper. When a user wishes to replenish the developer supply, the user may remove the dummy cover 250 to insert a replacement developer cartridge 100 in the cartridge receiving recess 213 (FIG. 2).
[0074] In one embodiment of the invention, when the developer cartridge 100 is inserted
in the cartridge receiving recess 213, the optical sensor 12, arranged inside the image forming apparatus 10, faces the remaining developer detecting unit 120 through the sensor hole 215, so that the light emitting unit 12a of the optical sensor 12 faces the first optical guide 121, and the light receiving unit 12b of the optical sensor 12 faces the second optical guide 122. In alternative embodiments of the invention, an optical sensor may be disposed in place of the sensor hole 215 on the developing unit 200, or an optical sensor may be disposed on the developer cartridge 100 facing the first optical guide 121 and the second optical guide 122.
[0075] When the developer cartridge 100 is installed within the cartridge receiving recess
213, the developer discharge port 111 is open, and a developer inlet port (not shown) of the developing unit 200 is also open. As a result, the developer of the developer cartridge 100 is fed into the developer feeding unit 212 of the developing unit 200.
[0076] In one embodiment of the invention, when the developing unit 200 housing the
developer cartridge 100 is received in the image forming apparatus 10, the direction in which the
18

developer cartridge 100 is inserted in the developing unit 200 and removed from the developing unit 200 may be in perpendicular relation with respect to the direction in which the developing unit 200 is inserted in the image forming apparatus 10 and removed from the image forming apparatus 10.
[0077] In one embodiment of the invention, a control unit (not shown) of the image
forming apparatus 10 may cause a light beam to be emitted to the remaining developer detecting unit 120 using the optical sensor 12, to determine whether the developer of the developer cartridge 100 is used up. The light emitting unit 12a of the optical sensor 12 emits a light beam to the first optical guide 121, and the emitted light is transferred toward the second optical guide 122 selectively depending on the amount of remaining developer.
[0078] For example, if the amount of remaining developer of the developer cartridge 100
is above a predetermined level, the developer fills up the space between the facing surfaces of the first and second light transfer surfaces 121b and 122b, thereby blocking light from passing from the first optical guide 121 to the second optical guide 122. As a result, in one embodiment of the invention the light receiving unit 12b of the optical sensor 12 fails to receive the light beam emitted from the light emitting unit 12a. In this situation, the optical sensor 12 emits a sensing signal to indicate that a sufficient amount of developer is remaining to the control unit of the image forming apparatus 10. Although, if a cleaning unit 130 is provided, the same may rotate, e.g., with the rotation of the agitating unit 112, thereby constantly wiping out the facing surfaces of the first and second light transfer surfaces 121b and 122b, the developer will quickly fill in the space between the first and second light transfer surfaces 121b and 122b to block the light beam from being passed from the first optical guide 121 to the second optical guide 122.
19

[0079] If the remaining developer in the developer cartridge 100 is substantially depleted,
light emitted is passed through the optical entry portion 121a, and reflected against one of more first reflective surface 12)c to be emitted to the first light transfer surface \7 lb, and the reflected light is passed through the empty space, enters the second light transfer surface 122b, and reflected against the second reflective surface 122c. In one embodiment of the invention, the light moves towards the light receiving unit 12b of the optical sensor 12 through the optical exit portion 122a. As a result, the light receiving unit 12b senses the light beam emitted from the light emitting unit 12a, and the optical sensor 12 outputs a signal to the control unit of the image forming apparatus 10 to indicate that the developer of the developer cartridge 100 has been substantially depleted.
[0080] Since, in an embodiment, the cleaning unit 130 continuously rotates along with
the agitating unit 112 to wipe out the facing surfaces of the first and second light transfer surfaces 121b and 122b, the space between the first and second optical guides 121 and 122 is emptied when the developer is used up. Accordingly, the light passes from the first light transfer surface 121b to the second light transfer surface 122b.
[0081] As explained above, from the fact that the light beam emitted to the first optical
guide 121 is blocked from being transferred to the Second optical guide 122 in the presence of the developer, but is transferred to the second optical guide 122 in the absence of the developer, whether or not the developer remains in the developer cartridge 100 may be determined. To this end, according to an embodiment, the image forming apparatus 10 may include a controller (not shown), which may be, e.g., a microprocessor, a microcontroller or the like, that includes a CPU to execute one or more computer instructions, e.g., to receive signal(s) from the optical sensor 12,
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to determine base on the received signal(s) whether sufficient amount of developer remains in the developer cartridge, and to control the image forming apparatus appropriately, e.g., to alert the user that replenishment of developer is needed, and may further include a memory device, e.g., a Random Access Memory (RAM), Read-Only-Memory (ROM), a flesh memory, or the like, to store the one or more computer instructions.
[0082] In one embodiment of the invention the first and second light transfer surfaces
121b and 122b may be arranged in the proximity to the developer discharge port 111. For example, the first and second light transfer surfaces 121b and 122b may be arranged directly above the developer discharge port 111, as illustrated in FIG. 4. The space between the first and second light transfer surfaces 121b and 122b is detected most accurately when the first and second light transfer surfaces 121b and 122b are arranged as close as possible to the developer discharge port 111. If the first and second light transfer surfaces 121b and 122b are arranged away from the developer discharge port 111, the optical sensor 12 may erroneously determine that the developer is used up while there is still developer inside the developer cartridge 100. However, if other design considerations make placement of the first and second light transfer surfaces 121band 122b away from the developer discharge port 111 desirable, the invention may still be practiced in such a design.
[0083] According to one aspect of the invention, the optical sensor 12 may detect the
amount of the remaining developer of the developer cartridge 100 as well as the presence/absence of the developer. As the developer recedes over time, the developer ripples, particularly at the areas contacting the ends of the first and second optical guides 121 and 122, while being conveyed toward the developer discharge port 111 due to the movement of the
21

agitating unit 112. As the developer ripples, the space between the first and second optical transfer surfaces 121b and 122b is occasionally emptied, thereby intermittently passing the light beam from the first optical guide 121 towards the second optical guide 122. As a result, the light receiving unit 12b of the optical sensor 12 may receive the light beam from the light emitting unit 12a.
[0084] The relation between the amount of remaining developer and the number of
occasions that the light beam passing the first optical guide 121 reaches the second optical guide
122, can be defined. For example, if it is established according to an embodiment of the
invention, that the light beam passing the first optical guide 121 arrives at the second optical
guide 122 two times per second when the remaining developer amount is approximately 50% of
the full level, the optical sensor 12 may determine that the amount of the remaining developer is
50% of the full level based on the fact that the optical sensor 12 detects the light beam from the
light emitting unit 12a arriving at the light receiving unit 12b two times per second. Other
embodiments may have different relations between remaining developer and number of times the
light beam travels through the remaining developer detecting unit 120, and the 50% full at two
times per second relationship is only disclosed as an example. By storing a database of the
sensed signals of the optical sensor 12 according to different levels of the developer, the amount
of remaining developer inside the developer cartridge 100 can be determined.
[0085] While an embodiment of the invention employs the optical sensor 12 to detect the
amount of the remaining developer, it should be understood that the main object of the present invention is to provide a sensor to detect the amount of remaining developer in the developer cartridge 110.
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[0086] Accordingly, not only the optical sensor 12. but also other types of sensors that
can detect the developer amount can be employed. For example, a piezo sensor may be arranged in the proximity to the developer discharge port to measure the amount of remaining developer based on the weight and vibration of the developer. Alternatively, considering that the developer is generally a conductive material, a capacitance type sensor may be employed, in which a plurality of electrodes are arranged near the developer to detect the electric current flowing the electrodes or the difference of the voltages. A sensor to physically detect the amount of the remaining developer may also be arranged.
[0087] The foregoing embodiments and advantages are merely examples and are not to
be construed as limiting the present invention. The present teaching can be readily applied to various other embodiments. Also, the description of the embodiments of the present invention is intended to be illustrative, and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art.
23

We claim:
1. A developer cartridge, comprising:
a cartridge body comprising a developer discharge port;
a remaining developer detecting unit arranged in proximity of the developer discharge port; and
an agitating unit rotatably arranged inside the cartridge body to convey the developer accommodated in the cartridge body toward the developer discharge port.
2. The developer cartridge of claim 1, wherein the remaining developer detecting unit is arranged above the developer discharge port.
3. The developer cartridge of claim 1, wherein the remaining developer detecting unit comprises:
a first optical guide comprising a light entry portion arranged on one end to face a light emitting unit of an optical sensor arranged on a main body of an image forming apparatus, and a first light transfer surface formed on the other end; and
a second optical guide comprising a light exit portion arranged on one end to face a light receiving unit of the optical sensor, and a second light transfer surface formed on the other end,
wherein the first and second light transfer surfaces are arranged to face each other at a predetermined distance from each other.
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4. The developer cartridge of claim 3. wherein the light entry portion and the light exit portion are arranged in a co-planar relation with each other, so that a first optical path in which a light beam enters the light entry portion and a second optical path in which the light beam exits the light exit portion are parallel to each other.
5. The developer cartridge of claim 4, wherein the first optical guide comprises one or more first reflective surface to reflect the light beam emitted from the light emitting unit towards the second light transfer surface via the first light transfer surface, and the second optical guide comprises one or more second reflective surface to reflect the light beam received at the second light transfer surface towards the light exit portion.
6. The developer cartridge of claim 5, wherein an angle of incidence and an angle of reflection of the light of the first and second reflective surfaces are at 45° from each other.
7. The developer cartridge of claim 3, further comprising a cleaning unit interposed between the first and second light transfer surfaces, to wipe the first and second light transfer surfaces.
8. The developer cartridge of claim 7, wherein the cleaning unit is rotated together with the agitating unit.
9. The developer cartridge of claim 7, wherein the cleaning unit comprises:
25

a rotating axis that rotate together with the agitating unit; and
a cleaning member arranged on the rotating axis to wipe the first and second light transfer surfaces in a rotating motion.
10. The developer cartridge of claim 9, wherein the cleaning member is rotated between a first position and a second position, in which the cleaning member in the first position is brought into contact with , and to thereby wipe, the first and second light transfer surfaces, the cleaning member in the second position being away from the first and second light transfer surfaces so as not to interfere with an optical path of the light bean passing through the first and second light transfer surfaces.
11. The developer cartridge of claim 3, wherein the first and second light transfer surfaces are arranged above the developer discharge port.
12. The developer cartridge of claim 3, wherein the surface of the light entry portion that faces the light emitting unit of the optical sensor and the surface of the light exit portion that faces the light receiving unit of the optical sensor are each formed as a circular convex lens.
13. The developer cartridge of claim 1, wherein the developer cartridge is detachably received into a developing cartridge of an image forming apparatus, the developer discharge
26

port being formed at a bottom of the cartridge body, and in proximity of a front end with respect to a direction of inserting the cartridge body into the developing cartridge.
14. A developing unit, comprising:
a developing cartridge; and
a developer cartridge removably received in the developing cartridge, the developer cartridge comprising,
a developer discharge port, and
a remaining developer detecting unit arranged in proximity of the developer discharge port, and an agitating unit rotatably arranged inside the developer cartridge to convey developer accommodated in the developer cartridge toward the developer discharge port,
wherein the developing cartridge comprises a sensor hole formed to face the remaining developer detecting unit so that the remaining developer detecting unit is exposed through the sensor hole.
15. The developing unit of claim 14, wherein the remaining developer detecting unit is made from a light permitting material, and arranged above the developer discharge port formed on the bottom of the developer cartridge.
16. The developing unit of claim 15, wherein the remaining developer detecting unit comprises:
27

a first optical guide comprising a light entry portion arranged on one end to face a light emitting unit of an optical sensor arranged on a main body of an image forming apparatus, and a first light transfer surface formed on the other end; and
a second optical guide comprising a light exit portion arranged on one end to face a light receiving unit of the optical sensor, and a second light transfer surface formed on the other end,
wherein the light entry portion and the light exit portion are arranged in a co-planar relation with each other, so that optical paths in which a light beam enters the light entry portion, and in which the light beam exits the light exit portion are parallel to each other, and
wherein the first and second light transfer surfaces are arranged to face each other at a predetermined distance from each other.
17. The developing unit of claim 16, wherein the first optical guide comprises one or
more first reflective surface to reflect the light beam emitted from the light emitting unit
towards the second light transfer surface via the first light transfer surface, and the second
optical guide comprises one or more second reflective surface to reflect the light beam
received at the second light transfer surface towards the light exit portion, and
wherein an angle of incidence and an angle of reflection of the light of the first and second reflective surfaces are at 45° from each other.
18. An image forming apparatus, comprising:
a main body comprising an optical sensor comprising a light emitting unit and a light receiving unit to detect an amount of remaining developer;
28

a developing cartridge removably received in the main body, the developing cartridge comprising a sensor hole formed to face the optical sensor; and
a developer cartridge removably received in the developing cartridge, the developer cartridge comprising,
a developer discharge port,
a remaining developer detecting unit arranged, in a position proximate to the developer discharge port, and to face the optical sensor through the sensor hole when the developer cartridge is received in the developing cartridge, and
an agitating unit rotatably arranged inside the developer cartridge to convey the developer accommodated in the cartridge body toward the developer discharge port.
19. A developer cartridge, comprising:
a cartridge body defining an inner volume for storing therein a quantity of developer, the cartridge body including a developer discharge port, through which the developer is discharged from the inner volume;
a developer detecting unit disposed in the inner volume at a location proximate to the developer discharge port, the developer detecting unit being configured to detect the presence of developer in the vicinity of the developer discharge port; and
an agitating unit rotatably arranged inside the cartridge body to move the developer accommodated in the inner volume toward the developer discharge port.
20. The developer cartridge according to claim 19, wherein the developer
detecting unit is disposed above the developer discharge port.
29

21. The developer cartridge according to claim 19, wherein the developer detecting unit comprises:
a first optical guide comprising a light entry portion arranged on one end thereof to receive light from a light emitting unit of an optical sensor and a first light transfer surface formed on the other end of the first optical guide; and
a second optical guide comprising a second light transfer surface formed on one end thereof, the second light transfer surface being spaced apart from, and facing, the first light transfer surface, and a light exit portion formed on the other end of the second optical guide to face a Tight receiving unit of the optical' sensor.
22. The developer cartridge according to claim 21, wherein the light entry portion and the light exit portion are arranged to be on a common plane so that the first optical path along which a light beam enters the light entry portion and the second optical path along which the light beam exits the light exit portion are parallel to each other.
23. The developer cartridge according to claim 21, wherein:
the first optical guide comprises one or more first reflective surfaces connecting, and thereby defining a first optical path between, the light entry portion and the first light transfer surface, the one or more first reflective surfaces reflecting the light received through the light entry portion toward the first light transfer surface, and
wherein the second optical guide comprises one or more second reflective surfaces connecting the second light transfer surface and the light exit portion, the one or more second reflective surfaces reflecting the light received through the second light transfer surface
30

a light source disposed on the cartridge body and positioned so that the light source transmits the light to the light entry portion; and
a light sensor disposed on the cartridge body and positioned so that the light sensor receives the light from the light exit portion.
29. A developing unit, comprising:
a developing cartridge body;
a developer feeding unit disposed in the developing cartridge body, the developer feeding unit being configured to feed developer to a photosensitive medium for developing a latent image formed on the photosensitive medium;
a developer storage chamber for storing therein a quantity of the developer, the developer storage chamber including a developer discharge port, through which the developer is discharged from the developer storage chamber to the developer feeding unit;
a developer detecting unit disposed in the developer storage chamber at a location proximate to the developer discharge port, the developer detecting unit being configured to detect the presence of the developer in the vicinity of the developer discharge port; and
an agitating unit rotatably arranged inside the developer storage chamber to move the developer accommodated in the developer storage chamber toward the developer discharge port.
30. The developing unit according to claim 29, wherein the developer
detecting unit comprises:
32

a first optical guide comprising a light entry portion arranged on one end thereof to receive light from a light emitting unit of an optical sensor and a first light transfer surface formed on the other end of the first optical guide; and
a second optical guide comprising a second light transfer surface formed on one end thereof, the second light transfer surface being spaced apart from, and facing, the first light transfer surface, and a light exit portion formed on the other end of the second optical guide to face a light receiving unit of the optical sensor.
31. The developing unit according to claim 30, wherein the light entry portion and the light exit portion are arranged to be on a common plane so that the first optical path along which a light beam enters the light entry portion and the second optical path along which the light beam exits the light exit portion are parallel to each other.
32. The developing unit according to claim 30, wherein:
the first optical guide comprises one or more first reflective surfaces connecting, and thereby defining a first optical path between, the light entry portion and the first Ught transfer surface, the one or more first reflective surfaces reflecting the light received through the light entry portion toward the first light transfer surface, and
wherein the second optical guide comprises one or more second reflective surfaces connecting the second light transfer surface and the light exit portion, the one or more second reflective surfaces reflecting the light received through the second light transfer surface toward the light exit portion to form a second optical path between the second light transfer surface and the light exit portion.
33

33. The developing unit according to claim 32, wherein each of an angle of incidence and an angle of reflection of the light of each of the one or more first reflective surfaces and the one or more second reflective surface is 45°.
34. The developing unit according to claim 30, further comprising:
a cleaning member disposed in the developer storage chamber, the cleaning member being capable of being interposed between the first and second light transfer surfaces to wipe the developer off the first and second light transfer surfaces.
35. The developing unit according to claim 34, wherein:
the cleaning member rotates about an rotational axis of the agitating unit between a first position and a second position, the cleaning member in the first position being brought into contact with the first and second light transfer surfaces, and the cleaning member in the second position being away from the first and second light transfer surfaces so as not to interfere with the optical path of the light between the first and second light transfer surfaces.
36. The developing unit according to claim 30, wherein the light entry portion and the light exit portions are arranged to be exposed outside the developing cartridge body.
37. The developing unit according to claim 30, wherein each of the light entry portion and the light exit portions is formed as a circular convex lens.
38. The developing unit according to claim 30, wherein the developer
detecting unit further comprises:
34

a light source disposed on the developing cartridge body and positioned so that the light source transmits the light to the light entry portion; and
a light sensor disposed on the developing cartridge body and positioned so that the light sensor receives the light from the light exit portion.
, 39. The developing unit according to claim 30, wherein the developer storage chamber comprises a developer cartridge removably received in the developing unit, the developer cartridge being housed in a developer cartridge body, and
wherein the light entry portion and the light exit portions are arranged to be exposed outside the developer cartridge body.
40. The developing unit according to claim 38, wherein the developer detecting unit further comprises:
a light source disposed on the developer cartridge body and positioned so that the light source transmits the light to the light entry portion; and
a light sensor disposed on the developer cartridge body and positioned so that the light sensor receives the light from the light exit portion.
Dated this 29th day of September, 2008.

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Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=6yjMuBqIctz+XQ5Rc3k5SQ==&loc=vsnutRQWHdTHa1EUofPtPQ==

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Patent Number

268778

Indian Patent Application Number

2099/MUM/2008

PG Journal Number

38/2015

Publication Date

18-Sep-2015

Grant Date

16-Sep-2015

Date of Filing

29-Sep-2008

Name of Patentee

SAMSUNG ELECTRONICS CO., LTD.

Applicant Address

416, MAETAN-DONG, YEONGTONG-GU, SUWON-SI. GYEONGGI-DO,

Inventors:

#	Inventor's Name	Inventor's Address
1	KWEON, DAE-SEOB	108-1904, HWANGGOL-MAEUL JUGONG 1DANJI APARTMENT, YEONGTONG-DONG, YEONGTONG-GU, SUWON-SI, GYEONGGI-DO,
2	SUR, JEAN-MAN	B-301, 1057-9, GWONSEON-DONG, GWONSEON-GU, SUWON-SI, GYEONGGI-DO,
3	NOH, JOO-HWAN	2606-402, BAEKHYEON-MAEUL SOEHAE GRANGBLE, DONGBAEK-DONG, GIHEUNG-GU, YONGIN-SI, GYEONGGI-DO,

PCT International Classification Number

G03G21/18

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2008-16464	2008-02-22	Republic of Korea