Patent US3796490A successfully refreshed from Google Patents.
US3796490A
Expired / Lapsed
US
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Electrostatic modulator for controlling flow of charged particles
Assignee: Markem Imaje Corp
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Filing: 1972-05-15
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Granted: 1974-03-12
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Expires: 1992-05-15
Abstract
Abstract A system for controlling the flow of charged particles and for modulated aperture electrostatic printing. An apertured screen having substantially the entire surfaces formed of a dielectric material is charged with like charges over substantially all its surfaces to develop fringing fields in the apertures. The charge distributed across one side of the screen is selectively dissipated in accordance with a pattern to be reproduced thereby establishing a bipolar electrostatic latent image as a modification of the fringing fields for density control of a flow of charged particles directed through the screen. The screen may be formed with dielectric thicker on one face than the other to initially carry a higher potential and provide a uniform charge inequality or potential difference through the screen apertures, oriented to enhance the flow of charged particles through the screen. Full modulation control of particle flow is therefore possible with a single selective charge dissipation. For electrostatic reproduction a print-receiving medium is interposed in the modulated particle flow passing through the screen.
Inventors
- 👤 Gerald L Pressman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:22
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/22; G03G15/34; G03G15/344; G03G15/346
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
114 words
An electrostatic modulator for controlling the flow of charged particles comprising: an apertured screen comprising an electrically conductive screen base having substantially its entire surface enclosed by electrically insulative dielectric material, said dielectric material on one side of the screen being substantially thicker than the other side so that one side of said screen has the ability to acquire electrical surface potential more quickly than the other side; means for charging the insulative material over substantially the entire surfaces of the screen with like charges; and means for selectively dissipating the charge across one side of the screen in accordance with a pattern to be reproduced, thereby to establish a bipolar electrostatic latent image.
Claim 2
Dependent Claim
114 words
An electrostatic modulator for controlling the flow of charged particles comprising: an apertured screen comprising an electrically conductive screen base having substantially its entire surface enclosed by electrically insulative dielectric material, said dielectric material on one side of the screen being substantially thicker than the other side so that one side of said screen has the ability to acquire electrical surface potential more quickly than the other side; means for charging the insulative material over substantially the entire surfaces of the screen with like charges; and means for selectively dissipating the charge across one side of the screen in accordance with a pattern to be reproduced, thereby to establish a bipolar electrostatic latent image.
Claim 3
Dependent Claim
28 words
An electrostatic modulator as set forth in claim 1 wherein the dielectric material on said one side of the screen exhibits increased electrical conductivity in response to radiation.
Claim 4
Dependent Claim
22 words
An electrostatic modulator as set forth in claim 1 wherein the dielectric material on said one side of the screen is photoconductive.
Claim 5
Dependent Claim
138 words
An electrostatic modulator for selective electrostatic control of a stream of charged particles comprising: a conductive apertured screen having its surface coated with insulative material so that the conductive screen is substantailly unexposed said insulative material being substantially thicker on one side of said screen so that one side of said screen is characterized by the ability to acquire electrical surface potential at a greater rate than the insulative material on the other side of said screen when both sides are exposed to equivalent streams of electrical charging radiation; means for establishing and distributing electric charges of like polarity on the insulative material over substantially all the surfaces of the screen; and means for selectively dissipating the charges established on the coated insulative material on one side of the screen in accordance with a pattern to be reproduced.
Claim 6
Dependent Claim
138 words
An electrostatic modulator for selective electrostatic control of a stream of charged particles comprising: a conductive apertured screen having its surface coated with insulative material so that the conductive screen is substantailly unexposed said insulative material being substantially thicker on one side of said screen so that one side of said screen is characterized by the ability to acquire electrical surface potential at a greater rate than the insulative material on the other side of said screen when both sides are exposed to equivalent streams of electrical charging radiation; means for establishing and distributing electric charges of like polarity on the insulative material over substantially all the surfaces of the screen; and means for selectively dissipating the charges established on the coated insulative material on one side of the screen in accordance with a pattern to be reproduced.
Claim 7
Dependent Claim
26 words
An electrostatic modulator as set forth in claim 4 wherein the thicker insulative material on one side of the conductive apertured screen comprises a photoconductive material.
Claim 8
Dependent Claim
50 words
An electrostatic modulator as set forth in claim 5 wherein is further provided means for projecting a pattern of light onto the photoconductive material on one side of the screen in accordance with an image to be reproduced and means for maintaining a fixed electric potential on the conductive screen.
Claim 9
Dependent Claim
132 words
A modulated screen electrostatic printing system comprising: a conductive screen base having two sides and a plurality of holes therethrough, a coating of insulative material over one side of the conductive base and the inner surfaces of said holes, and a coating of photOconductive material over the other side of the conductive base whereby the surfaces of said conductive screen base are substantially unexposed; means for charging said screen with like charges over substantially the entire coated surfaces of the screen; means for projecting a pattern of light of onto the photoconductive material coated on one side of the screen in accordance with an image to be reproduced; means for maintaining a fixed electric potential on the conductive screen; and means for establishing a flow of charged particles directed through said screen.
Claim 10
Dependent Claim
132 words
A modulated screen electrostatic printing system comprising: a conductive screen base having two sides and a plurality of holes therethrough, a coating of insulative material over one side of the conductive base and the inner surfaces of said holes, and a coating of photOconductive material over the other side of the conductive base whereby the surfaces of said conductive screen base are substantially unexposed; means for charging said screen with like charges over substantially the entire coated surfaces of the screen; means for projecting a pattern of light of onto the photoconductive material coated on one side of the screen in accordance with an image to be reproduced; means for maintaining a fixed electric potential on the conductive screen; and means for establishing a flow of charged particles directed through said screen.
Claim 11
Independent Claim
192 words
A system for selective electrostatic control of a stream of charged particles comprising: a screen comprising a core and an electrically insulative coating substantially entirely covering said core, said coating substantially thicker on one side of said screen than on the other side; means for establishing across said coating spaced parallel coplanar arrays of bipolar electrostatic fields having lines of force oriented generally parallel to the perpendicular axes of said arrays, said fields formed between opposed charges of equal magnitude, those of said charges located on opposed faces of the exterior surface of said coating resulting in different surface potentials on said opposed faces of said screen, said different potentials on said opposed faces establishing lines of force oriented to enhance the motion of a stream of charged particles directed fron one side of the array through said array; and means for selectively reducing and neutralizing said fields at different portions of said arrays by dissipating certain of said charges according to a desired pattern thereby to provide a bipolar electrostatic latent image for density control over a continuous scale of the flow of charged particles directed through said arrays of fields.
Claim 12
Independent Claim
192 words
A system for selective electrostatic control of a stream of charged particles comprising: a screen comprising a core and an electrically insulative coating substantially entirely covering said core, said coating substantially thicker on one side of said screen than on the other side; means for establishing across said coating spaced parallel coplanar arrays of bipolar electrostatic fields having lines of force oriented generally parallel to the perpendicular axes of said arrays, said fields formed between opposed charges of equal magnitude, those of said charges located on opposed faces of the exterior surface of said coating resulting in different surface potentials on said opposed faces of said screen, said different potentials on said opposed faces establishing lines of force oriented to enhance the motion of a stream of charged particles directed fron one side of the array through said array; and means for selectively reducing and neutralizing said fields at different portions of said arrays by dissipating certain of said charges according to a desired pattern thereby to provide a bipolar electrostatic latent image for density control over a continuous scale of the flow of charged particles directed through said arrays of fields.
Claim 13
Dependent Claim
28 words
A system as set forth in claim 8 wherein said means for selectively reducing and neutralizing said fields includes means responsive to the intensity of light projected thereon.
Claim 14
Dependent Claim
132 words
An electrostatic modulator for controlling the flow of charged particles comprising: means for depositing a uniform first electrostatic charge layer establishing a uniform first surface potential over a first predetermined surface area; means for establishing a uniform second electrostatic charge layer establishing a uniform second surface potential different from said first surface potential over a second predetermined surface area spaced from and opposed to said first predetermined surface area, said first and second charge layers formed of like polarity charges; means for selectively dissipating charges from said second electrostatic charge layer according to a pattern to be reproduced thereby to establish a bipolar electrostatic latent image; said predetermined surface areas located on an apertured screen to permit passage of charged particles directed through the screen according to the established electrostatic latent image.
Claim 15
Dependent Claim
132 words
An electrostatic modulator for controlling the flow of charged particles comprising: means for depositing a uniform first electrostatic charge layer establishing a uniform first surface potential over a first predetermined surface area; means for establishing a uniform second electrostatic charge layer establishing a uniform second surface potential different from said first surface potential over a second predetermined surface area spaced from and opposed to said first predetermined surface area, said first and second charge layers formed of like polarity charges; means for selectively dissipating charges from said second electrostatic charge layer according to a pattern to be reproduced thereby to establish a bipolar electrostatic latent image; said predetermined surface areas located on an apertured screen to permit passage of charged particles directed through the screen according to the established electrostatic latent image.
Claim 16
Dependent Claim
28 words
An electrostatic modulator as set forth in claim 10 wherein said means for selectively dissipating charges from the second charge layer includes means responsive to light projected thereon.
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) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |