US3998634A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Powder electrophotographic method
Assignee: Fujifilm Holdings Corp
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Filing: 1975-06-04
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Granted: 1976-12-21
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Expires: 1995-06-04
Abstract
Abstract An electrophotographic method comprising image-wise exposing the surface of a support having thereon (a) first photoconductive powders either positively or negatively electrically charged and (b) electroconductive powders having a surface resistivity of 10 10 Ωsq or less or second photoconductive powders charged in a reverse polarity to that of the first photoconductive powders to form an electrostatic latent image, and then removing either the imagewise exposed or unexposed portion of the powders to form an image.
Inventors
- 👤 Masakazu Iwasa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:38
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/0821; G03G9/0823; G03G15/00; G03G15/22; G03G15/34; G03G15/342; G03G5/00; G03G5/02; G03G5/04; G03G9/09; G03G9/0926; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/101
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
197 words
An electrophotographic method comprising image-wise exposing the surface of a support having thereon at least one layer of (a) first photoconductive powders either positively or negatively electrically charged and (b) further powders selected from the group consisting of electroconductive powders having a surface resistivity of 10 10 Ωsq. or less and second photoconductive powders, said further powders being applied to said surface of said support no earlier than the application of said first photoconductive powders to the support and said further powders being charged in a reverse polarity to that of the first photoconductive powders where the total amount of the positive and negative charges on said first and further powders is approximately zero to thereby form an electrostatic latent image as a result of said image-wise exposing the photoconductive powders where any of said further powders in the upper portion of said layer are phototransparent in at least a portion of the wavelength range to which said first photoconductive powders not in said upper portion are sensitive, said photoconductive and electroconductive powders being 1 - 200 microns in size, and then removing either the image-wise exposed or unexposed portion of the powders to form an image.
Claim 2
Dependent Claim
197 words
An electrophotographic method comprising image-wise exposing the surface of a support having thereon at least one layer of (a) first photoconductive powders either positively or negatively electrically charged and (b) further powders selected from the group consisting of electroconductive powders having a surface resistivity of 10 10 Ωsq. or less and second photoconductive powders, said further powders being applied to said surface of said support no earlier than the application of said first photoconductive powders to the support and said further powders being charged in a reverse polarity to that of the first photoconductive powders where the total amount of the positive and negative charges on said first and further powders is approximately zero to thereby form an electrostatic latent image as a result of said image-wise exposing the photoconductive powders where any of said further powders in the upper portion of said layer are phototransparent in at least a portion of the wavelength range to which said first photoconductive powders not in said upper portion are sensitive, said photoconductive and electroconductive powders being 1 - 200 microns in size, and then removing either the image-wise exposed or unexposed portion of the powders to form an image.
Claim 3
Dependent Claim
18 words
The method of claim 1 where said first and second photoconductive powders are the same kind of powder.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein said first and second photoconductive powders have different spectral sensitivies.
Claim 5
Dependent Claim
16 words
The method of claim 1 wherein said first and second photoconductive powders have different visible appearances.
Claim 6
Dependent Claim
32 words
The method of claim 1 wherein said removing of the exposed portion of the powders is effected by using an air stream, said method including applying a bias voltage during said removing.
Claim 7
Dependent Claim
50 words
The method of claim 1 wherein said the oppositely charged powders are separately scattered in two layers whereby electric double layers are formed, said further powders being in the top layer and phototransparent in at least a portion of the wavelength range to which said first photoconductive powders are sensitive.
Claim 8
Dependent Claim
67 words
The method of claim 1 wherein said oppositely charged powders are scattered simultaneously on said support as a single layer where said first photoconductive powders are phototransparent in at least a portion of the wavelength range to which said second photoconductive powders are sensitive and said further powders are phototransparent in at least a portion of the wavelength range to which said first photoconductive powders are sensitive.
Claim 9
Dependent Claim
11 words
The method of claim 1 wherein said support is electrically insulating.
Claim 10
Dependent Claim
26 words
The method of claim 8 where said support is charged in an amount less than about one-fifth of the charge of the positive or negative powder.
Claim 11
Dependent Claim
12 words
The method of claim 1 wherein said support is a metallic support.
Claim 12
Dependent Claim
15 words
The method of claim 1 where said average particle diameter is 1 - 150 microns.
Claim 13
Dependent Claim
132 words
An electrophotographic method comprising image-wise exposing the surface of a support having thereon at least one layer of first photoconductive powders either positively or negatively electrically charged and further photoconductive powders charged in a reverse polarity to that of the first photoconductive powders where the total amount of the positive and negative charges on said photoconductive powders is approximately zero to thereby form an electrostatic latent image where any of said further photoconductive powders in the upper portion of said layer are phototransparent in at least a portion of the wavelength range to which said first photoconductive powders not in said upper portion are sensitive, said photoconductive powders being 1 - 200 microns in size, and then removing either the image-wise exposed or unexposed portion of the powders to form an image.
Claim 14
Dependent Claim
132 words
An electrophotographic method comprising image-wise exposing the surface of a support having thereon at least one layer of first photoconductive powders either positively or negatively electrically charged and further photoconductive powders charged in a reverse polarity to that of the first photoconductive powders where the total amount of the positive and negative charges on said photoconductive powders is approximately zero to thereby form an electrostatic latent image where any of said further photoconductive powders in the upper portion of said layer are phototransparent in at least a portion of the wavelength range to which said first photoconductive powders not in said upper portion are sensitive, said photoconductive powders being 1 - 200 microns in size, and then removing either the image-wise exposed or unexposed portion of the powders to form an image.
Claim 15
Dependent Claim
141 words
An electrophotographic method comprising forming on a support a layer of photoconductive powders, forming on said layer of photoconductive powders a layer of electroconductive powders having a surface resistivity of 10 10 Ωsq. or less and a phototransparency in at least a portion of the wavelength range to which said photoconductive powders are sensitive, image-wise exposing the surface of said support having thereon said photoconductive powders either positively or negatively electrically charged and said electroconductive powders charged in a reverse polarity to that of the photoconductive powders where the total amount of the positive and negative charges on said photoconductive and electroconductive powders is approximately zero to thereby form an electrostatic latent image, said photoconductive and electroconductive powders being 1 - 200 microns in size, and then removing the image-wise exposed or unexposed portion of the powders to form an image.
Claim 16
Dependent Claim
141 words
An electrophotographic method comprising forming on a support a layer of photoconductive powders, forming on said layer of photoconductive powders a layer of electroconductive powders having a surface resistivity of 10 10 Ωsq. or less and a phototransparency in at least a portion of the wavelength range to which said photoconductive powders are sensitive, image-wise exposing the surface of said support having thereon said photoconductive powders either positively or negatively electrically charged and said electroconductive powders charged in a reverse polarity to that of the photoconductive powders where the total amount of the positive and negative charges on said photoconductive and electroconductive powders is approximately zero to thereby form an electrostatic latent image, said photoconductive and electroconductive powders being 1 - 200 microns in size, and then removing the image-wise exposed or unexposed portion of the powders to form an image.
Claim 17
Dependent Claim
121 words
An electrophotographic method comprising forming on an electroconductive support a layer of electroconductive powders having a surface resistivity of 10 10 Ωsq. or less, forming on said layer of electroconductive powders a layer of photoconductive powders, image-wise exposing the surface of said support having thereon said photoconductive powders either positively or negatively electrically charged and said electroconductive powders charged in a reverse polarity to that of the photoconductive powders where the total amount of the positive and negative charges on said photoconductive and electroconductive powders is approximately zero to thereby form an electrostatic latent image, said photoconductive powders being 1 - 200 microns in size, and then removing the image-wise exposed or unexposed portion of the powders to form an image.
Claim 18
Dependent Claim
121 words
An electrophotographic method comprising forming on an electroconductive support a layer of electroconductive powders having a surface resistivity of 10 10 Ωsq. or less, forming on said layer of electroconductive powders a layer of photoconductive powders, image-wise exposing the surface of said support having thereon said photoconductive powders either positively or negatively electrically charged and said electroconductive powders charged in a reverse polarity to that of the photoconductive powders where the total amount of the positive and negative charges on said photoconductive and electroconductive powders is approximately zero to thereby form an electrostatic latent image, said photoconductive powders being 1 - 200 microns in size, and then removing the image-wise exposed or unexposed portion of the powders to form an image.
Claim 19
Dependent Claim
173 words
An electrophotographic method comprising image-wise exposing the surface of an electroconductive support having thereon at least one layer of (a) first photoconductive powders either positively or negatively electrically charged and (b) further powders selected from the group consisting of electroconductive powders having a surface resistivity of 10 10 Ωsq. or less and second photoconductive powders, said further powders being charged in a reverse polarity to that of the first photoconductive powders where the total amount of the positive and negative charges on said photoconductive and further powders is approximately zero to thereby form an electrostatic latent image as a result of said image-wise exposing the photoconductive powders where any of said further powders in the upper portion of said layer are phototransparent in at least a portion of the wavelength range to which said first photoconductive powders not in said upper portion are sensitive, said photoconductive and electroconductive powders being 1 - 200 microns in size, and then removing either the image-wise exposed or unexposed portion of the powders to form an image.
Claim 20
Dependent Claim
173 words
An electrophotographic method comprising image-wise exposing the surface of an electroconductive support having thereon at least one layer of (a) first photoconductive powders either positively or negatively electrically charged and (b) further powders selected from the group consisting of electroconductive powders having a surface resistivity of 10 10 Ωsq. or less and second photoconductive powders, said further powders being charged in a reverse polarity to that of the first photoconductive powders where the total amount of the positive and negative charges on said photoconductive and further powders is approximately zero to thereby form an electrostatic latent image as a result of said image-wise exposing the photoconductive powders where any of said further powders in the upper portion of said layer are phototransparent in at least a portion of the wavelength range to which said first photoconductive powders not in said upper portion are sensitive, said photoconductive and electroconductive powders being 1 - 200 microns in size, and then removing either the image-wise exposed or unexposed portion of the powders to form an image.
Claim 21
Dependent Claim
46 words
The method of claim 1 where said removing of the exposed portion of the powders is effected by using an air stream and the amounts of said positive and negative charges may be different from each other within 15% based on the amount of the charge.
Claim 22
Dependent Claim
46 words
The method of claim 12 where said removing of the exposed portion of the powders is effected by using an air stream and the amounts of said positive and negative charges may be different from each other within 15% based on the amount of the charge.
Claim 23
Dependent Claim
46 words
The method of claim 13 where said removing of the exposed portion of the powders is effected by using an air stream and the amounts of said positive and negative charges may be different from each other within 15% based on the amount of the charge.
Claim 24
Dependent Claim
46 words
The method of claim 14 where said removing of the exposed portion of the powders is effected by using an air stream and the amounts of said positive and negative charges may be different from each other within 15% based on the amount of the charge.
Claim 25
Dependent Claim
46 words
The method of claim 15 where said removing of the exposed portion of the powders is effected by using an air stream and the amounts of said positive and negative charges may be different from each other within 15% based on the amount of the charge.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-12-21 | 1980-06-21 | 1980-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-12-21 | 1984-06-21 | 1984-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-12-21 | 1988-06-21 | 1988-12-21 | $7700.00 | Window Closed / Lapsed |