US3879197A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrophotographic copying process
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1969-09-03
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Granted: 1975-04-22
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Expires: 1989-09-03
Abstract
Abstract This disclosure relates to an electrophotographic copying process suitable for use in a multiple copying system. The process is characterized by use of an electrophotographic medium comprising photosensitive organic compounds which are either (1) insulating prior to irradiation and substantially permanently conductive subsequent to irradiation or (2) conductive prior to irradiation and substantially permanently insulating subsequent to irradiation. The proccess comprises the steps of exposing the electrophotographic medium to a pattern of activating radiation to produce a latent image with a conductivity pattern that is irreversible and permanently altered and externally applying an electrical charge at any suitable time thereby forming an electrostatic pattern which can be developed by any of the known electrophotographic developing techniques. By consecutively repeating the steps of charging and developing, an indefinite number of prints can be made which are comparable in image quality and density to the original with a single step of exposure to the pattern of activating radiation. Consequently, a multiple copy system results which is substantially faster than conventional electrophotographic systems due to elimination of a requirement for repeated exposure of the electrophotographic medium to a source of activating radiation for each copy.
Inventors
- 👤 Richard F Bartlett
- 👤 Laura K Case
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:06
CPC Classifications
G; G03; G03G; G03G5/00; G03G5/02; G03G5/026
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
128 words
A PROCESS FOR FORMING ONE OR MORE COPIES OF AN ORIGINAL COMPRISING THE STEPS OF: A. FORMING A COPY MEDIUM BY COATING A SUPPORT WITH AN ORGANIC PHOTOSENSITIVE MATERIAL WHICH UNDERGOES A SUBSTANTIALLY IRREVERSIBLE CHEMICAL CHANGE UPON BEING STRUCK WITH ACTINIC RADIATION TO SUBSTANTIALLY PERMANENTLY ALTER ITS CONDUCTIVITY, SAID PHOTOSENSITIVE MATERIAL COMPRISING AN N-VINYL CARBAZOLE AND AN ORGANIC HALOGEN DERIVATIVE CAPABLE OF FORMING A HYDROHALIDE ACID UPON BEING STRUCK WITH ACTINIC RADIATION; B. EXPOSING SAID COPU MEDIUM TO AN IMAGE PATTERN OF ACTINIC RADIATION REPRESENTATIVE OF SAID ORIGINAL WHEREBY SAID IRREVERSIBLE CHEMICAL CHANGE OCCURS; C. APPLYING AN ELECTRICAL FIELD ACROSS SAID EXPOSED COPY MEDIUM THEREBY PROVIDING AN ELECTROSTATIC IMAGE PATTERN; AND, D. DEVELOPING SAID ELECTROSTATIC IMAGE PATTERN WITH IMAGEFORMING MATERIALS TO FORM A VISIBLE IMAGE OF SAID ORIGINAL.
Claim 2
Dependent Claim
128 words
A PROCESS FOR FORMING ONE OR MORE COPIES OF AN ORIGINAL COMPRISING THE STEPS OF: A. FORMING A COPY MEDIUM BY COATING A SUPPORT WITH AN ORGANIC PHOTOSENSITIVE MATERIAL WHICH UNDERGOES A SUBSTANTIALLY IRREVERSIBLE CHEMICAL CHANGE UPON BEING STRUCK WITH ACTINIC RADIATION TO SUBSTANTIALLY PERMANENTLY ALTER ITS CONDUCTIVITY, SAID PHOTOSENSITIVE MATERIAL COMPRISING AN N-VINYL CARBAZOLE AND AN ORGANIC HALOGEN DERIVATIVE CAPABLE OF FORMING A HYDROHALIDE ACID UPON BEING STRUCK WITH ACTINIC RADIATION; B. EXPOSING SAID COPU MEDIUM TO AN IMAGE PATTERN OF ACTINIC RADIATION REPRESENTATIVE OF SAID ORIGINAL WHEREBY SAID IRREVERSIBLE CHEMICAL CHANGE OCCURS; C. APPLYING AN ELECTRICAL FIELD ACROSS SAID EXPOSED COPY MEDIUM THEREBY PROVIDING AN ELECTROSTATIC IMAGE PATTERN; AND, D. DEVELOPING SAID ELECTROSTATIC IMAGE PATTERN WITH IMAGEFORMING MATERIALS TO FORM A VISIBLE IMAGE OF SAID ORIGINAL.
Claim 3
Dependent Claim
128 words
A process for forming one or more copies of an original comprising the steps of: a. forming a copy medium by coating a support with an organic photosensitive material which undergoes a substantially irreversible chemical change upon being struck with actinic radiation to substantially permanently alter its conductivity, said photosensitive material comprising an N-vinyl carbazole and an organic halogen derivative capable of forming a hydrohalide acid upon being struck with actinic radiation; b. exposing said copy medium to an image pattern of actinic radiation representative of said original whereby said irreversible chemical change occurs; c. applying an electrical field across said exposed copy medium thereby providing an electrostatic image pattern; and, d. developing said electrostatic image pattern with image-forming materials to form a visible image of said original.
Claim 4
Dependent Claim
128 words
A process for forming one or more copies of an original comprising the steps of: a. forming a copy medium by coating a support with an organic photosensitive material which undergoes a substantially irreversible chemical change upon being struck with actinic radiation to substantially permanently alter its conductivity, said photosensitive material comprising an N-vinyl carbazole and an organic halogen derivative capable of forming a hydrohalide acid upon being struck with actinic radiation; b. exposing said copy medium to an image pattern of actinic radiation representative of said original whereby said irreversible chemical change occurs; c. applying an electrical field across said exposed copy medium thereby providing an electrostatic image pattern; and, d. developing said electrostatic image pattern with image-forming materials to form a visible image of said original.
Claim 5
Dependent Claim
33 words
A process of claim 1 wherein the electrostatic image pattern is developed by contacting the copy medium with a finely divided particulate toner material and the toner is fixed to said electrophotographic medium.
Claim 6
Dependent Claim
12 words
A process of claim 2 where the toner is fixed by heat.
Claim 7
Dependent Claim
48 words
A process of claim 1 wherein the electrostatic image pattern is developed by contacting the copy medium with a finely divided particulate toner material to provide a visible toner image, transferring the toner image to an image-receiving sheet, and fixing the toner image pattern on the receiving sheet.
Claim 8
Dependent Claim
128 words
A process for producing multiple copies of an original comprising: a. forming a copy medium by coating a support with an organic photosensitive material which undergoes a substantially irreversible chemical change upon being struck with actinic radiation to substantially permanently alter its conductivity, said photosensitive material comprising an N-vinyl carbazole and an organic halogen derivative capable of forming a hydrohalide acid upon being struck with actinic radiation; b. exposing said copy medium to an image pattern of actinic radiation representative of said original whereby said irreversible change occurs; c. applying an electric field across said exposed copy medium thereby providing an electrostatic image pattern; d. developing said electrostatic image pattern with image-forming materials to form a visible image of said original; and, e. repeating steps c. and d.
Claim 9
Dependent Claim
128 words
A process for producing multiple copies of an original comprising: a. forming a copy medium by coating a support with an organic photosensitive material which undergoes a substantially irreversible chemical change upon being struck with actinic radiation to substantially permanently alter its conductivity, said photosensitive material comprising an N-vinyl carbazole and an organic halogen derivative capable of forming a hydrohalide acid upon being struck with actinic radiation; b. exposing said copy medium to an image pattern of actinic radiation representative of said original whereby said irreversible change occurs; c. applying an electric field across said exposed copy medium thereby providing an electrostatic image pattern; d. developing said electrostatic image pattern with image-forming materials to form a visible image of said original; and, e. repeating steps c. and d.
Claim 10
Dependent Claim
21 words
A process of claim 5 wherein step c. is accomplished by charging one surface of the copy medium by corona discharge.
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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) | 1978-04-21 | 1978-10-21 | 1979-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-21 | 1982-10-21 | 1983-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-21 | 1986-10-21 | 1987-04-22 | $7700.00 | Window Closed / Lapsed |