US4876561A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Printing apparatus and toner/developer delivery system therefor
Assignee: Xerox Corp
•
Filing: 1988-05-31
•
Granted: 1989-10-24
•
Expires: 2008-05-31
Abstract
Abstract Direct electrostatic printing (DEP) is optimized by presenting well charged toner to a charged toner conveyor which conveys the toner to an apertured printhead structure for propulsion therethrough. The charged toner conveyor comprises a plurality of electrodes wherein the electrode density (i.e. over 400 electrodes per inch) is relatively large for enabling a high toner delivery rate without risk of air breakdown. The printhead structure is constructed for minimization of aperture clogging. To this end the thickness of the printhead structure is about 0.025 mm and the aperture diameter (i.e. 0.15 mm) is large compared to the printhead thickness.
Inventors
- 👤 Fred W. Schmidlin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 02:26
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/0822; B; B41; B41J; B41J2/00; B41J2/385; B41J2/41; B41J2/415; B41J2/4155; G03G15/22; G03G15/34; G03G15/344; G03G15/346; G03G2217/00; G03G2217/0008; G03G2217/0025
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
140 words
Direct electrostatic printing apparatus, said apparatus comprising: a supply of well charged toner particles; an apertured printhead structure; an image receiving member disposed adjacent one side of said apertured printhead; a charged toner conveyor including a plurality of spaced-apart electrodes, said charged toner conveyor being disposed adjacent said supply of well charged toner and the opposite side of said apertured printhead for moving toner particles from said supply to an area adjacent said printhead; a source of electrical power operatively connected to said spaced-apart electrodes for creating wave energy for effecting the movement of toner particles; said printhead being electrically biased to establish an electrostatic field thereacross; and said apertured printhead having a thickness in the direction of toner particle movement that is relatively small to thereby maximize the field strength of said electrostatic field whereby aperture clogging is minimized.
Claim 2
Dependent Claim
140 words
Direct electrostatic printing apparatus, said apparatus comprising: a supply of well charged toner particles; an apertured printhead structure; an image receiving member disposed adjacent one side of said apertured printhead; a charged toner conveyor including a plurality of spaced-apart electrodes, said charged toner conveyor being disposed adjacent said supply of well charged toner and the opposite side of said apertured printhead for moving toner particles from said supply to an area adjacent said printhead; a source of electrical power operatively connected to said spaced-apart electrodes for creating wave energy for effecting the movement of toner particles; said printhead being electrically biased to establish an electrostatic field thereacross; and said apertured printhead having a thickness in the direction of toner particle movement that is relatively small to thereby maximize the field strength of said electrostatic field whereby aperture clogging is minimized.
Claim 3
Dependent Claim
29 words
Apparatus according to claim 1 wherein said spaced-apart electrodes have an electrode density enabling a relatively high toner delivery rate to said apertured printhead without risk of air breakdown.
Claim 4
Dependent Claim
15 words
Apparatus according to claim 2 wherein said electrode density comprises approximately 250 electrodes per inch.
Claim 5
Dependent Claim
23 words
Apparatus according to claim 3 wherein the apertures in said printhead have a large diameter relative to the thickness of the printhead structure.
Claim 6
Dependent Claim
17 words
Apparatus according to claim 4 wherein the thickness of said apertured printhead is less than 0.1 mm.
Claim 7
Dependent Claim
15 words
Apparatus according to claim 5 wherein the diameter of said apertures is approximately 0.15 mm.
Claim 8
Dependent Claim
13 words
Apparatus according to claim 6 wherein said image receiving member comprises plain paper.
Claim 9
Dependent Claim
23 words
Apparatus according to claim 6 wherein the width of each electrode of the charged toner conveyor is in the order of 0.050 mm.
Claim 10
Dependent Claim
19 words
Apparatus according to claim 5 wherein the spacing between electrodes of said charged toner conveyor is approximately 0.050 mm.
Claim 11
Dependent Claim
19 words
Apparatus according to claim 9 wherein said voltage is operated at a frequency of approximately 1000 Hz or greater.
Claim 12
Dependent Claim
10 words
Apparatus according to claim 10 wherein said electrodes are coplanar.
Claim 13
Dependent Claim
16 words
Apparatus according to claim 1 including means for removing unused toner from said charged toner conveyor.
Claim 14
Dependent Claim
21 words
Apparatus according to claim 1 wherein said printhead is spaced from said charged toner conveyor a distance less than three wavelengths.
Claim 15
Dependent Claim
20 words
Apparatus according to claim 9 wherein the distance between said charged toner conveyor and said printhead is approximately 0.3 mm.
References Cited (Backward Citations)
US3689935A
Cited
US3801869A
Cited
US3778678A
Cited
US3872361A
Cited
US4562447A
Cited
US4491855A
Cited
US4568955A
Cited
US4515882A
Cited
US4647179A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-23 | 1993-04-24 | 1993-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-23 | 1997-04-24 | 1997-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-23 | 2001-04-24 | 2001-10-24 | $7700.00 | Window Closed / Lapsed |