Patent US4388391A successfully refreshed from Google Patents.
US4388391A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the manufacture of a lithographic printing form by electrophotography
Assignee: Hoechst AG
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Filing: 1981-02-09
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Granted: 1983-06-14
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Expires: 2001-02-09
Abstract
Abstract Disclosed is a process for manufacturing a lithographic printing form by electrophotographic means, comprising the steps of uniformly charging an oleophilic photoconductive layer which is present on an electrically conductive hydrophilic layer support and which contains a photoconductor and a binder; image-wise exposing the charged photoconductive layer to produce a charge image; developing the charge image with toner to produce a toner image comprised of imaged areas and non-image areas; fixing the toner image; decoating the non-image areas of the photoconductive layer to bare the electrically conductive layer support; coating the bared areas of the layer support with a solution comprising a water-soluble, but hydrocarbon-insoluble film-forming polymer and a vinyl phosphonic acid compound; drying the coating solution to form a uniform coating; and removing the toner image by rinsing with a hydrocarbon composition containing aromatic portions in an amount of at least about 20% by weight. Also disclosed is an improved printing form made by this process.
Inventors
- 👤 Loni Schell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 10:28
CPC Classifications
G; G03; G03G; G03G13/00; G03G13/26; G03G13/28; Y; Y10; Y10S; Y10S101/00; Y10S101/37
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
173 words
A process for the manufacture of a lithographic printing form by electrophotographic means, comprising the steps of: uniformly charging an oleophilic photoconductive layer which is present on an electrically conductive hydrophilic layer support and which contains a photoconductor and a binder; image-wise exposing the charged photoconductive layer to produce a charge image; developing the charge image with toner to produce a toner image comprised of imaged areas and non-image areas; fixing the toner image; decoating the non-image areas of the photoconductive layer to bare the electrically conductive layer support; coating the bared areas of the layer support with a solution comprising a water-soluble, but hydrocarbon-insoluble film-forming polymer and a vinyl phosphonic acid compound; drying the coating solution to form a uniform coating; and removing the toner image by rinsing with a hydrocarbon composition containing aromatic portions in an amount of at least about 20% by weight, whereby said coating containing said vinyl phosphonic acid compound prevents deposition in non-imaged background areas of toner image substances which would cause toning of said printing form.
Claim 2
Dependent Claim
173 words
A process for the manufacture of a lithographic printing form by electrophotographic means, comprising the steps of: uniformly charging an oleophilic photoconductive layer which is present on an electrically conductive hydrophilic layer support and which contains a photoconductor and a binder; image-wise exposing the charged photoconductive layer to produce a charge image; developing the charge image with toner to produce a toner image comprised of imaged areas and non-image areas; fixing the toner image; decoating the non-image areas of the photoconductive layer to bare the electrically conductive layer support; coating the bared areas of the layer support with a solution comprising a water-soluble, but hydrocarbon-insoluble film-forming polymer and a vinyl phosphonic acid compound; drying the coating solution to form a uniform coating; and removing the toner image by rinsing with a hydrocarbon composition containing aromatic portions in an amount of at least about 20% by weight, whereby said coating containing said vinyl phosphonic acid compound prevents deposition in non-imaged background areas of toner image substances which would cause toning of said printing form.
Claim 3
Dependent Claim
24 words
A process as claimed in claim 1, further comprising the step of decoating the non-image areas of the layer support by rinsing with water.
Claim 4
Dependent Claim
19 words
A process as claimed in claim 1, wherein said polymer is selected from dextrin, gum arabic or polyvinyl alcohol.
Claim 5
Dependent Claim
17 words
A process as claimed in claim 1, wherein the vinyl phosphonic acid compound comprises polyvinyl phosphonic acid.
Claim 6
Dependent Claim
27 words
A process as claimed in claim 1, wherein the concentration of the vinyl phosphonic acid compound in the solution is between about 0.05 and 10% by weight.
Claim 7
Dependent Claim
27 words
A process as claimed in claim 5, wherein the concentration of the vinyl phosphonic acid compound in the solution is between about 0.2 and 4% by weight.
Claim 8
Dependent Claim
16 words
A process as claimed in claim 1, wherein the hydrophilic layer support comprises anodically oxidized aluminum.
Claim 9
Dependent Claim
22 words
A process as claimed in claim 1, wherein the hydrocarbon composition contains from about 70 to 100% by weight of aromatic portions.
Claim 10
Dependent Claim
26 words
A process as claimed in claim 1, wherein the aromatic portions of the hydrocarbon composition comprise alkyl-substituted benzenes having between about 8 and 15 carbon atoms.
Claim 11
Dependent Claim
16 words
A process as claimed in claim 1, wherein the photoconductive layer employed contains an organic photoconductor.
Claim 12
Dependent Claim
25 words
A process as claimed in claim 1, wherein the photoconductive layer employed contains a binder which is insoluble in water and soluble in aqueous-alkaline solutions.
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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) | 1986-06-13 | 1986-12-13 | 1987-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-13 | 1990-12-13 | 1991-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-13 | 1994-12-13 | 1995-06-14 | $7700.00 | Window Closed / Lapsed |