US3815989A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrophotographic copy systems
Assignee: Nashua Corp
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Filing: 1972-12-14
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Granted: 1974-06-11
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Expires: 1992-12-14
Abstract
Abstract In electrophotographic copy systems in which the electrostatic image is developed from a liquid developer containing charged toner particles, and subsequently squeegeed to remove excess developer, improved definition and less background results if a charge of polarity the same as the image is applied to the squeegee.
Inventors
- 👤 A Davis
- 👤 P Agostino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:34
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/10; G03G15/11
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
128 words
In an electrophotographic copy apparatus which includes means for forming an electrostatic latent image on a photoconductive insulating surface, means for contacting said surface with a liquid developer containing toner particles suspended in a carrier liquid, a resilient, non-conductive squeegee roller for removing excess developer from said surface, and means for pressing said surface into contact with a copy sheet to transfer the developed image from said surface to said sheet, the improvement comprising a corona discharge device for applying to the surface of the squeegee roller an electrostatic charge of the same polarity as the charge of the electrostatic latent image, said charge being sufficient to cause said roller to remove toner particles from the substantially discharged background areas of the developed image on said photoconductive surface.
Claim 2
Dependent Claim
128 words
In an electrophotographic copy apparatus which includes means for forming an electrostatic latent image on a photoconductive insulating surface, means for contacting said surface with a liquid developer containing toner particles suspended in a carrier liquid, a resilient, non-conductive squeegee roller for removing excess developer from said surface, and means for pressing said surface into contact with a copy sheet to transfer the developed image from said surface to said sheet, the improvement comprising a corona discharge device for applying to the surface of the squeegee roller an electrostatic charge of the same polarity as the charge of the electrostatic latent image, said charge being sufficient to cause said roller to remove toner particles from the substantially discharged background areas of the developed image on said photoconductive surface.
Claim 3
Dependent Claim
123 words
In an electrophotographic copy process in which an electrophotographic surface is charged and exposed to form an electrostatic image, is contacted with a liquid developer containing positively charged toner particles suspended in a carrier liquid, is contacted with a resilient, non-conductive squeegee roller to remove excess developer from said surface, and is then pressed against a copy sheet to transfer the image thereto, the improvement comprising providing a corona discharge adjacent said roller to apply to the surface of said squeegee roller an electrostatic charge of the same polarity as that of the latent image and of a magnitude sufficient to cause said roller to remove toner particles from the substantially discharged background areas of the developed latent image on said photoconductive surface.
Claim 4
Dependent Claim
123 words
In an electrophotographic copy process in which an electrophotographic surface is charged and exposed to form an electrostatic image, is contacted with a liquid developer containing positively charged toner particles suspended in a carrier liquid, is contacted with a resilient, non-conductive squeegee roller to remove excess developer from said surface, and is then pressed against a copy sheet to transfer the image thereto, the improvement comprising providing a corona discharge adjacent said roller to apply to the surface of said squeegee roller an electrostatic charge of the same polarity as that of the latent image and of a magnitude sufficient to cause said roller to remove toner particles from the substantially discharged background areas of the developed latent image on said photoconductive surface.
Claim 5
Dependent Claim
22 words
Apparatus as set forth in claim 1 further comprising means for mechanically removing toner particles from the surface of said squeegee roller.
Claim 6
Dependent Claim
15 words
Apparatus as set forth in claim 1 wherein said removing means comprises a doctor blade.
Claim 7
Dependent Claim
114 words
In electrophotographic copy equipment having means for forming an electrostatic latent image on a photoconductive surface, developing apparatus comprising: means for contacting said surface with a liquid developer containing toner particles suspended in a carrier liquid, said developer being applied at a bias potential of the same polarity as the latent image; a resilient, non-conductive squeegee roller for removing excess developer from said surface; and a corona discharge device for applying to the surface of said roller an electrostatic charge of the same polarity as the latent image, said charge being sufficient to cause said roller to remove toner particles from the substantially discharged background areas of the developed image on said photoconductive surface.
Claim 8
Dependent Claim
114 words
In electrophotographic copy equipment having means for forming an electrostatic latent image on a photoconductive surface, developing apparatus comprising: means for contacting said surface with a liquid developer containing toner particles suspended in a carrier liquid, said developer being applied at a bias potential of the same polarity as the latent image; a resilient, non-conductive squeegee roller for removing excess developer from said surface; and a corona discharge device for applying to the surface of said roller an electrostatic charge of the same polarity as the latent image, said charge being sufficient to cause said roller to remove toner particles from the substantially discharged background areas of the developed image on said photoconductive surface.
Claim 9
Dependent Claim
22 words
Apparatus as set forth in claim 5 further comprising means for mechanically removing toner particles from the surface of said squeegee roller.
Claim 10
Dependent Claim
15 words
Apparatus as set forth in claim 4 wherein said removing means comprises a doctor blade.
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) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |