Patent US4197121A successfully refreshed from Google Patents.
US4197121A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making electrophotographic images with a uniform exposure step
Assignee: US Philips Corp
•
Filing: 1978-06-22
•
Granted: 1980-04-08
•
Expires: 1998-06-22
Abstract
Abstract The duration of use of spectrally sensitized pigment bonding agent layers which are to be used a number of times is substantially increased by performing floodlighting, after the development and/or transfer and prior to the recharging, with a light which is suitable per se for the image formation, but which is substantially not absorbed by the dye.
Inventors
- 👤 Wolfgang Eckenbach
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:30
CPC Classifications
G; G03; G03G; G03G21/00; G03G21/06; G03G21/08
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
121 words
In an electrophotographic process of forming a multiple image comprising the steps of: electrostatically charging a photosensitive layer containing inorganic photoconductive particles, spectrally sensitized by an organic dye and which are distributed in a polymer binding agent, exposing of said layer to thereby form a charge image corresponding to the image to be formed, developing said charge image with a liquid or powdery developer, transfering said image to a final image carrier and, subsequent to the development of said charge image, uniformly exposing said photosensitive layer to light, the improvement wherein the light employed for said uniform exposure comes within a wavelength range such that said light is suitable for forming the image but is substantially not absorbed by the dye.
Claim 2
Dependent Claim
121 words
In an electrophotographic process of forming a multiple image comprising the steps of: electrostatically charging a photosensitive layer containing inorganic photoconductive particles, spectrally sensitized by an organic dye and which are distributed in a polymer binding agent, exposing of said layer to thereby form a charge image corresponding to the image to be formed, developing said charge image with a liquid or powdery developer, transfering said image to a final image carrier and, subsequent to the development of said charge image, uniformly exposing said photosensitive layer to light, the improvement wherein the light employed for said uniform exposure comes within a wavelength range such that said light is suitable for forming the image but is substantially not absorbed by the dye.
Claim 3
Dependent Claim
34 words
A method as claimed in claim 1, characterized in that the amount of light used during the uniform exposure amounts to from 0.5 to 5 times the amount of light required for image formation.
Claim 4
Dependent Claim
24 words
A method as claimed in claim 1, characterized in that uniform exposure is performed with light having wavelengths of between 250 and 520 nm.
Claim 5
Dependent Claim
38 words
A method as claimed in claim 3, in which the photoconductive particles of the photosensitive layer consists of zinc oxide, characterized in that the uniform exposure is performed with light having wavelengths of between 300 and 390 nm.
References Cited (Backward Citations)
GB867668A
Cited
US3418115A
Cited
US3525612A
Cited
US3558308A
Cited
US3781108A
Cited
US4052206A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-04-08 | 1983-10-08 | 1984-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-08 | 1987-10-08 | 1988-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-08 | 1991-10-08 | 1992-04-08 | $7700.00 | Window Closed / Lapsed |