US3873310A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of controlling the brightness acceptance range and tonal contrast of a xerographic plate
Assignee: Individual
•
Filing: 1973-10-29
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Granted: 1975-03-25
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Expires: 1993-10-29
Abstract
Abstract A method of controlling the brightness acceptance range and tonal contrast of a xerographic plate having an insulating overlayer, which includes the steps of charging and imagewiseexposing the plate, and repeating these steps at least once more, to cumulatively store the latent electrostatic images formed by each of the charging and exposing steps on the plate. The plate is then recharged and flood-exposed, and electrostatically attractable particles and deposited thereon to develop the latent electrostatic image.
Inventors
- 👤 Lloyd F Bean
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:29
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/22; G03G15/226
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
140 words
THE METHOD OF CONTROLLING THE TONAL CONTRAST AND EXTENDING THE BRIGHTNESS ACCEPTANCE RANGE OF AN ELECTROSTATOGRAPHIC PLATE HAVING A CONDUCTIVE SUBSTRATE, A PHOTOCONDUCTIVE LAYER AND AN ELECTRICALLY INSULATING LAYER OVERLAYING SAID PHOTOCONDUCTIVE LAYER COMPRISING THE STEPS OF: APPLYING UNIFORMLY A FIRST ELECTROSTATIC CHARGE IN A FIRST POLARITY TO SAID PLATE. IMAGEWISE EXPOSING SAID PLATE A FIRST TIME TO STORE A CHARGE PATTERN REPRESENTING A PORTION OF THE TONAL INFORMATION OF AN ORIGINAL, APPLYING A SECOND ELECTROSTATIC CHARGE IN SAID FIRST POLARITY TO SAID PLATE, IMAGEWISE EXPOSING SAID PLATE IN REGISTRATION WITH SAID FIRST EXPOSURE AT A LOWER AMOUNT A SECOND TIME THAN THAT OF THE FIRST TIME STORE AN ADDITIONAL PORTION OF TONAL INFORMATION IN THE PLATE, APPLYING A THIRD ELECTROSTATIC CHARGE TO SAID PLATE, AND FLOODEXPOSING SAID PLATE TO LIGHT TO FORM A LATENT ELECTROSTATIC IMAGE IN SAID PLATE.
Claim 2
Independent Claim
140 words
THE METHOD OF CONTROLLING THE TONAL CONTRAST AND EXTENDING THE BRIGHTNESS ACCEPTANCE RANGE OF AN ELECTROSTATOGRAPHIC PLATE HAVING A CONDUCTIVE SUBSTRATE, A PHOTOCONDUCTIVE LAYER AND AN ELECTRICALLY INSULATING LAYER OVERLAYING SAID PHOTOCONDUCTIVE LAYER COMPRISING THE STEPS OF: APPLYING UNIFORMLY A FIRST ELECTROSTATIC CHARGE IN A FIRST POLARITY TO SAID PLATE. IMAGEWISE EXPOSING SAID PLATE A FIRST TIME TO STORE A CHARGE PATTERN REPRESENTING A PORTION OF THE TONAL INFORMATION OF AN ORIGINAL, APPLYING A SECOND ELECTROSTATIC CHARGE IN SAID FIRST POLARITY TO SAID PLATE, IMAGEWISE EXPOSING SAID PLATE IN REGISTRATION WITH SAID FIRST EXPOSURE AT A LOWER AMOUNT A SECOND TIME THAN THAT OF THE FIRST TIME STORE AN ADDITIONAL PORTION OF TONAL INFORMATION IN THE PLATE, APPLYING A THIRD ELECTROSTATIC CHARGE TO SAID PLATE, AND FLOODEXPOSING SAID PLATE TO LIGHT TO FORM A LATENT ELECTROSTATIC IMAGE IN SAID PLATE.
Claim 3
Dependent Claim
47 words
The method according to claim 1, including repeating the steps of charging and exposing said plate with decreasing amount of exposure a number of times so that additional portions of tonal information are successively stored in said plate for increasing the fidelity of the latent electrostatic image.
Claim 4
Dependent Claim
17 words
The method according to claim 2, including the step of developing said image with electrostatically attractable particles.
Claim 5
Dependent Claim
27 words
The method according to claim 3, including the step of transferring the developed image to a copy sheet, and fixing the transferred image to the copy sheet.
Claim 6
Dependent Claim
17 words
The method according to claim 2, each pair of the charging and exposure steps are performed simultaneously.
Claim 7
Dependent Claim
24 words
The method according to claim 2, the exposure steps take place in succession while the electrostatographic plate is being charged continuously at one level.
Claim 8
Dependent Claim
28 words
The method according to claim 1, wherein the charge potentials of successive charging steps are adjusted so that a substantially linear potential versus log exposure relationship is obtained.
Claim 9
Dependent Claim
31 words
The method according to claim 7, wherein the polarity and magnitude of the final charge step is adjusted to reduce the free surface potential of the xerographic plate to substantially zero.
Claim 10
Dependent Claim
24 words
The method according to claim 8, wherein the polarity of the final charge step is set opposite to that of the previous charging steps.
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) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |