Patent EP0345024A2 successfully refreshed from Google Patents.
EP0345024A2
Expired / Lapsed
EP
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Printing apparatus and toner/developer delivery system therefor
Assignee: Xerox Corp
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Filing: 1989-05-31
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Granted: —
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Expires: 2009-05-31
Abstract
Abstract Direct electrostatic printing (DEP) is optimized by presenting well charged toner (34) to a charged toner conveyor (18) which conveys the toner to an apertured printhead structure (14) for propulsion therethrough. The charged toner conveyor comprises a plurality of electrodes (24, 26, 28, 30) wherein the electrode density 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
EP
Data Source
google_patents
Last Synchronized
2026-10-25 10:00
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: 11
Claim 1
Independent Claim
125 words
Direct electrostatic printing apparatus, said apparatus comprising: means (20) for supplying charged toner particles ; an apertured printhead structure (14); a charged toner conveyor (18) including a plurality of spaced-apart electrodes (24, 26, 28, 30), said charged toner conveyor being positioned to move toner particles from said supply means to said printhead; a source (V₁, V₂, V₃, V₄) of a.c. power operatively connected to said spaced-apart electrodes for creating a travelling electrostatic wave pattern 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 thereby to maximize the field strength of said electrostatic field whereby aperture clogging is minimized.
Claim 2
Dependent Claim
125 words
Direct electrostatic printing apparatus, said apparatus comprising: means (20) for supplying charged toner particles ; an apertured printhead structure (14); a charged toner conveyor (18) including a plurality of spaced-apart electrodes (24, 26, 28, 30), said charged toner conveyor being positioned to move toner particles from said supply means to said printhead; a source (V₁, V₂, V₃, V₄) of a.c. power operatively connected to said spaced-apart electrodes for creating a travelling electrostatic wave pattern 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 thereby to 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
23 words
Apparatus according to claim 2 wherein said electrode density is at least 4 electrodes per mm and, preferably, approximately 10 electrodes per mm.
Claim 5
Dependent Claim
28 words
Apparatus according to any one of the preceding claims, wherein the apertures (40) in said printhead have a large diameter relative to the thickness of the printhead structure.
Claim 6
Dependent Claim
21 words
Apparatus according to any one of the preceding claims, 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
30 words
Apparatus according to any one of the preceding claims, wherein the width of each electrode of the charged toner conveyor is in the range of from 0.025 to 0.10 mm.
Claim 9
Dependent Claim
23 words
Apparatus according to any one of the preceding claims, wherein the spacing between the centres of the electrodes is twice the electrode width.
Claim 10
Dependent Claim
24 words
Apparatus according to any one of the preceding claims, wherein said power source is operated at a frequency of approximately 1000 Hz or greater.
Claim 11
Dependent Claim
30 words
Apparatus according to any one of the preceding claims, wherein said printhead is spaced from said charged toner conveyor a distance less than three wavelengths of the said wave pattern.
References Cited (Backward Citations)
No citation records indexed.
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