Patent US3893418A successfully refreshed from Google Patents.
US3893418A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Xerographic developing apparatus
Assignee: Xerox Corp
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Filing: 1974-05-30
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Granted: 1975-07-08
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Expires: 1994-05-30
Abstract
Abstract An apparatus for developing a latent xerographic image is disclosed. The development device comprises a toner supporting donor member adjacent, and in spaced relationship to, an image retaining member. Means are also provided to apply a pulsed electrical bias to the donor member to introduce an electrical field in the gap between the donor and image retaining member whereby the electroscopic particles are made more readily available to the charged image thereby resulting in fine image development. The pulse applied across the gap can be of two different frequencies to insure either good line copy quality or faithful tonal reproduction of an original. The instant donor development system enables reproduction of line and pictorial images.
Inventors
- 👤 Alan J Liebman
- 👤 Ii Henry T Chiavaroli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:06
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/065
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
115 words
An apparatus for developing a latent electrostatic image recorded on an image retaining member comprising: a. a donor member for supporting a uniform layer of electroscopic developing material adjacent to the image retaining member, said donor member and image retaining member being spatially disposed as to create a space gap between both members; b. means to selectively introduce high and low frequency pulse biases across said gap, said pulses being comprised of an activation potential segment in which electroscopic particles are released from the donor member and a development potential segment of different polarity in which the electroscopic particles in non-image areas are attracted towards the donor thereby preventing particle deposition in the non-image areas.
Claim 2
Independent Claim
115 words
An apparatus for developing a latent electrostatic image recorded on an image retaining member comprising: a. a donor member for supporting a uniform layer of electroscopic developing material adjacent to the image retaining member, said donor member and image retaining member being spatially disposed as to create a space gap between both members; b. means to selectively introduce high and low frequency pulse biases across said gap, said pulses being comprised of an activation potential segment in which electroscopic particles are released from the donor member and a development potential segment of different polarity in which the electroscopic particles in non-image areas are attracted towards the donor thereby preventing particle deposition in the non-image areas.
Claim 3
Dependent Claim
26 words
The apparatus of claim 1 wherein the low frequency is from about 2 to 5 kilo hertz and the high frequency is about 18-20 kilo hertz.
Claim 4
Dependent Claim
13 words
The apparatus of claim 1 wherein the high frequency is 20 kilo hertz.
Claim 5
Dependent Claim
16 words
The apparatus of claim 1 wherein the spatial gap measures from about 5 to 20 mils.
Claim 6
Dependent Claim
31 words
The apparatus of claim 1 wherein the activation potential is a negative polarity of greater than 150 volts and the development potential is a positive polarity of greater than 400 volts.
Claim 7
Dependent Claim
19 words
The apparatus of claim 1 wherein the activation potential takes place from periods of about 5 to 100 microseconds.
Claim 8
Dependent Claim
17 words
The apparatus of claim 1 wherein the donor member is in the form of a rotatable cylinder.
Claim 9
Dependent Claim
31 words
The apparatus of claim 7 wherein the cylindrical donor comprises an aluminum substrate and an enamel surface layer containing an etched layer of copper in the form of a grid pattern.
Claim 10
Dependent Claim
15 words
The apparatuS of claim 8 wherein the grid contains 120 to 150 lines per inch.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-07 | 1979-01-06 | 1979-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-07 | 1983-01-06 | 1983-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-07 | 1987-01-06 | 1987-07-08 | $7700.00 | Window Closed / Lapsed |