US4444858A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing a lithographic printing plate
Assignee: Tokai University
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Filing: 1980-10-27
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Granted: 1984-04-24
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Expires: 2000-10-27
Abstract
Abstract A method of preparing a lithographic printing plate in which a toner image formed by electrophotographic process is transferred and fixed on a metal base lithographic printing plate having a thin insulating synthetic resin surface layer. Thereafter the synthetic resin layer on the non-image area is removed followed by removal of the toner to leave resin image areas.
Inventors
- 👤 Satoshi Nishibu
- 👤 Yasusuke Takahashi
- 👤 Gentaro Nagamatsu
- 👤 Toshibumi Sakata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:10
CPC Classifications
G; G03; G03G; G03G13/00; G03G13/26; G03G13/28; G03G13/283
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
118 words
A method of making a lithographic printing plate comprising forming a toner image, coating a metal plate with a 0.5 to 10μ thick, electrically insulating, durable synthetic resin layer, transferring the toner image onto the surface of the layer of resin by a bias roll method, fixing the toner image on the resin layer to provide image areas on the surface of the resin to be protected by the toner from a subsequently applied organic solvent, removing the resin from the non-toner protected areas of the plate with said organic solvent, thereafter dissolving the toner without dissolving the remaining resin to leave said resin image areas, and performing a hydrophilic treatment on the non-resin-coated areas of the plate.
Claim 2
Independent Claim
118 words
A method of making a lithographic printing plate comprising forming a toner image, coating a metal plate with a 0.5 to 10μ thick, electrically insulating, durable synthetic resin layer, transferring the toner image onto the surface of the layer of resin by a bias roll method, fixing the toner image on the resin layer to provide image areas on the surface of the resin to be protected by the toner from a subsequently applied organic solvent, removing the resin from the non-toner protected areas of the plate with said organic solvent, thereafter dissolving the toner without dissolving the remaining resin to leave said resin image areas, and performing a hydrophilic treatment on the non-resin-coated areas of the plate.
Claim 3
Dependent Claim
25 words
A method according to claim 1 wherein said step of coating comprises coating the plate with a layer of synthetic resin 1 to 5μ thick.
Claim 4
Dependent Claim
43 words
A method according to claim 1 wherein said step of coating comprises, coating said plate with a thin layer of a durable synthetic resin having toner retaining characteristics and being soluble in a solvent in which the fixed toner image is essentially insoluble.
Claim 5
Dependent Claim
46 words
A method according to claim 1 wherein said step of coating a plate comprises, coating a metal base plate for lithographic printing, said metal base plate being selected from the group consisting of an aluminum plate, a zinc plate, a bimetal plate, and a trimetal plate.
Claim 6
Dependent Claim
20 words
A method according to claim 4 wherein said aluminum plate for lithographic printing is a grained or anodized aluminum plate.
Claim 7
Dependent Claim
29 words
A method according to claim 1 wherein said step of forming a toner image comprises forming a toner image from a toner of a particle size less than 10μ.
Claim 8
Dependent Claim
16 words
A method according to claim 6 wherein said toner has a particle size of about 5μ.
Claim 9
Dependent Claim
34 words
A method according to claim 1 wherein said step of transferring the toner image comprises transferring the toner image onto the surface of the resin coated plate by applying pressure and an electric field.
Claim 10
Dependent Claim
27 words
A method according to claim 8 wherein said toner image is transferred to the surface of the resin coated plate under the action of a bias roller.
Claim 11
Dependent Claim
29 words
A method according to claim 1 wherein said step of coating comprises, coating said plate with a synthetic resin soluble in an organic solvent or an alkaline aqueous solution.
References Cited (Backward Citations)
US3063859A
Cited
US3071070A
Cited
US3315600A
Cited
US3647499A
Cited
BE756595A
Cited
US3860436A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-04-24 | 1987-10-24 | 1988-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-24 | 1991-10-24 | 1992-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-24 | 1995-10-24 | 1996-04-24 | $7700.00 | Window Closed / Lapsed |