US3889637A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-biased development electrode and reproducing machine employing same
Assignee: Xerox Corp
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Filing: 1973-06-28
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Granted: 1975-06-17
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Expires: 1993-06-28
Abstract
Abstract A development apparatus for developing electrostatic charge patterns or images or a dielectric surface which includes an electrically biased development electrode in close proximity to the surface. The electrode is connected to ground potential through an impedance path which comprises at least one reversed biased zener diode. The electrode is self-biased with the biasing potential being a function of the breakdown voltage of the zener diode. The breakdown voltage of the diode is selected to give the desired electrode potential. Preferably, the apparatus includes means for changing the bias potential on the electrode. An electrostatographic reproducing apparatus employing the aforenoted developer apparatus is also claimed.
Inventors
- 👤 Arthur J North
- 👤 Raymond W Stover
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:14
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/09; G03G15/0907; G03G15/065
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
115 words
In a developing apparatus for developing electrostatic charge patterns on a surface, including an electrically biased development electrode in close proximity to said surface, said electrode being connected to a reference potential through an impedance means so that the charge produced on the electrode during the development of said pattern provides the bias potential for said electrode, the improvement wherein, said impedance means comprises: at least one zener diode connected between said electrode and said reference potential so that the charge produced on said electrode during the development of said pattern provides a reverse bias potential across said zener diode to cause it to stabilize the bias potential on said electrode at a desired level.
Claim 2
Dependent Claim
115 words
In a developing apparatus for developing electrostatic charge patterns on a surface, including an electrically biased development electrode in close proximity to said surface, said electrode being connected to a reference potential through an impedance means so that the charge produced on the electrode during the development of said pattern provides the bias potential for said electrode, the improvement wherein, said impedance means comprises: at least one zener diode connected between said electrode and said reference potential so that the charge produced on said electrode during the development of said pattern provides a reverse bias potential across said zener diode to cause it to stabilize the bias potential on said electrode at a desired level.
Claim 3
Dependent Claim
39 words
An apparatus as in claim 1 wherein said reference potential comprises ground potential and wherein said zener diode regulates within about plus or minus 10 percent of its nominal breakdown voltage at an electrode current of about 0.1 microampheres.
Claim 4
Dependent Claim
27 words
An apparatus as in claim 2 wherein said zener diode has a breakdown potential of less than about 50 volts above the background potential on said surface.
Claim 5
Dependent Claim
27 words
An apparatus as in claim 2 wherein said zener diode has a breakdown potential of less than about 100 volts below the background potential on said surface.
Claim 6
Dependent Claim
27 words
An apparatus as in claim 2 wherein a plurality of zener diodes are selectively connected between said electrode and said ground potential to provide said bias potential.
Claim 7
Dependent Claim
14 words
An apparatus as in claim 5 wherein said zener diodes are connected in series.
Claim 8
Dependent Claim
17 words
An apparatus as in claim 2 further including means for changing the bias potential on said electrode.
Claim 9
Dependent Claim
56 words
An apparatus as in claim 7 wherein said potential changing means comprises a plurality of zener diodes or combinations of zener diodes wherein each diode or diode combination has a differing breakdown potential, and switching means for selectively connecting one or more of said diodes or diode combinations between said development electrode and said ground potential.
Claim 10
Dependent Claim
16 words
An apparatus as in claim 8 wherein said developing means comprises a magnetic brush developing means.
Claim 11
Dependent Claim
142 words
In an electrostatic reproducing apparatus comprising a surface adapted to receive an electrostatic charge pattern, means for forming said electrostatic pattern on said surface, and means for developing said electrostatic charge pattern to render it visible, said development means including an electrically biased development electrode in close proximity to said surface, said electrode being connected to a reference potential through an impedance means so that the charge produced on the electrode during the development of said pattern provides the bias potential for said electrode, the improvement wherein, said impedance means comprises: at least one zener diode connected between said electrode and said reference potential so that the charge produced on said electrode during the development of said pattern provides a reverse bias potential across said zener diode to cause it to stabilize the bias potential on said electrode at a desired level.
Claim 12
Dependent Claim
142 words
In an electrostatic reproducing apparatus comprising a surface adapted to receive an electrostatic charge pattern, means for forming said electrostatic pattern on said surface, and means for developing said electrostatic charge pattern to render it visible, said development means including an electrically biased development electrode in close proximity to said surface, said electrode being connected to a reference potential through an impedance means so that the charge produced on the electrode during the development of said pattern provides the bias potential for said electrode, the improvement wherein, said impedance means comprises: at least one zener diode connected between said electrode and said reference potential so that the charge produced on said electrode during the development of said pattern provides a reverse bias potential across said zener diode to cause it to stabilize the bias potential on said electrode at a desired level.
Claim 13
Dependent Claim
39 words
An apparatus as in claim 10 wherein said reference potential comprises ground potential and wherein said zener diode regulates within about + or - 10 percent of its nominal breakdown voltage at an electrode current of about 0.1 microampheres.
Claim 14
Dependent Claim
30 words
An apparatus as in claim 11 wherein said at least one zener diode has a breakdown potential of less than about 50 volts above the background potential on said surface.
Claim 15
Dependent Claim
27 words
An apparatus as in claim 11 wherein said zener diode has a breakdown potential of less than about 100 volts below the background potential on said surface.
Claim 16
Dependent Claim
27 words
An apparatus as in claim 11 wherein a plurality of zener diodes are selectively connected between said electrode and said ground potential to provide said bias potential.
Claim 17
Dependent Claim
14 words
An apparatus as in claim 14 wherein said zener diodes are connected in series.
Claim 18
Dependent Claim
17 words
An apparatus as in claim 11 further including means for changing the bias potential on said electrode.
Claim 19
Dependent Claim
56 words
An apparatus as in claim 16 wherein said potential changing means comprises a plurality of zener diodes or combinations of zener diodes wherein each diode or diode combination has a differing breakdown potential, and switching means for selectively connecting one or more of said diodes or diode combinations between said development electrode and said ground potential.
Claim 20
Dependent Claim
16 words
An apparatus as in claim 16 wherein said development means comprises a magnetic brush development means.
Claim 21
Dependent Claim
53 words
An apparatus as in claim 16 wherein said surface comprises a photoconductive surface, and wherein said means for forming an electrostatic charge pattern comprises means for uniformly charging said photoconductive surface and means for providing a light image of an original to impinge upon said charged surface so as to form said pattern.
Claim 22
Dependent Claim
25 words
An apparatus as in claim 19 further including means for transferring the developed image from said photoconductive surface to a sheet of final support material.
References Cited (Backward Citations)
US3328193A
Cited
US3257223A
Cited
US3599605A
Cited
US3654893A
Cited
US3674532A
Cited
US3719165A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-16 | 1978-12-16 | 1979-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-16 | 1982-12-16 | 1983-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-16 | 1986-12-16 | 1987-06-17 | $7700.00 | Window Closed / Lapsed |