| Abstract |
Novel designs and method of manufacture of ink-jet printheads capable of providing ink-droplet tail-break-off control and preventing meniscus overshoot in order to overcome the puddling,pen directionally,and ruffle problems associated with thermal-ink-jet printing are disclosed.A printhead(80)for use in an ink delivery system includes a sbstrate(82)that has at least one ink ejector thereon.An orific-plate member(250)is positioned over and above the substrate.The office-plate member has at least one ink-transfer bore(286)extending therethrough.The orfice plate member further includes a top surface(254)that defines a top opening for the ink-transfer bore,a bottom surface that defines a bottom opening for the ink-transfer bore,and a counter-bore(400)in the top surface that is in fluid communication with the ink-transfer bore.the counter-bore can be concentric or non-concentric with the ink-transfer bore, a full or partial counter-bore,and symmetric or asymmetric.In addition,the counter-bore can also be deep enough to hold the ink meniscus.Lastly,the counter-bore can smooth, round and/or provide a more uniform edge around the ink-transfer bore.By providing one or more combitions of these features,the present invention is able to control the tail break-off of expelled ink-jet droplets and/or minimize the meniscus overflow. |