US3929591A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Novel lithographic plate and method
Assignee: Polychrome Corp
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Filing: 1974-08-26
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Granted: 1975-12-30
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Expires: 1994-08-26
Abstract
Abstract Aluminum base sheets for lithographic plates are produced which have been surface grained followed by electrolytically etching the surface utilizing alternating current in a phosphoric acid electrolyte and then anodizing the surface with direct current in a sulfuric acid electrolyte.
Inventors
- 👤 Simon Long Chu
- 👤 Ken-Ichi Shimazu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:56
CPC Classifications
C; C25; C25F; C25F3/00; C25F3/02; C25F3/04; B; B41; B41N; B41N3/00; B41N3/03; B41N3/034; C25D; C25D11/00; C25D11/02; C25D11/024; C25D11/04; Y; Y10; Y10S; Y10S205/00; Y10S205/921
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
207 words
A METHOD FOR PREPARING AN ALUMINUM SHEET BASE MEMBER FOR A LITHOGRAPHIC PRINTING PLATE, THE SURFACE OF WHICH IS ADAPTED TO RECEIVE A LIGHT SENSITIVE COATING THEREON, WHICH COMPRISES: A. GRAINING THE SURFACE OF SAID ALUMINUM SHEET BY TREATMENT THEREOF WITH A WET MASS OF FINE, HARD, ABRASIVE PARTICLES, SELECTED FROM THE GROUP CONSISTING OF SILICATES, OXIDES AND SULFATES; AND B. ETCHING SAID GRAINED ALUMINUM SHEET BY TREATMENT THEREOF WITH ALTERNATING CURRENT IN AN AQUEOUS ELECTROLYTIC SOLUTION COMPRISED OF FROM 20 TO ABOUT 50 PERCENT BY WEIGHT OF PHOSPHATE ELECTROLYTE SELECTED FROM THE GROUP CONSISTING OF ALKALI PHOSPHATES, ALKALINE EARTH PHOSPHATES, AMMONIUM PHOSPHATE AND PHOSPHORIC ACID, AND WHEREIN THE ALTERNATING CURRENT DENSITY IS FFROM ABOUT 10 TO 200 AMPERES PER SQUARE FOOT; SAID ETCHING SUFFICIENT TO INCREASE THE FINAL SURFACE REFLECTANCE OF SAID ALUMINUM SHEET BY AT LEAST ABOUT 5 PERCENT; AND C. ANODIZING SAID ETCHED ALUMINUM SHEET BY TREATMENT WITH DIRECT CURRENT IN AN AQUEOUS ELECTROLYTE SOLUTION COMPRISED OF FROM 8 TO 22 PERCENT BY WEIGHT OF SULFURIC ACID, AND WHEREIN THE DIRECT CURRENT VOLTAGE IS FROM 10 TO 25 VOLTS, AND THE CURRENT DENSITY IS FROM 10 TO 20 AMPERES PER SQUARE FOOT, TO PROVIDE A HARD, ABRASION RESISTANT, POROUS SURFACE ON SAID ALUMINUM SHEET.
Claim 2
Independent Claim
207 words
A METHOD FOR PREPARING AN ALUMINUM SHEET BASE MEMBER FOR A LITHOGRAPHIC PRINTING PLATE, THE SURFACE OF WHICH IS ADAPTED TO RECEIVE A LIGHT SENSITIVE COATING THEREON, WHICH COMPRISES: A. GRAINING THE SURFACE OF SAID ALUMINUM SHEET BY TREATMENT THEREOF WITH A WET MASS OF FINE, HARD, ABRASIVE PARTICLES, SELECTED FROM THE GROUP CONSISTING OF SILICATES, OXIDES AND SULFATES; AND B. ETCHING SAID GRAINED ALUMINUM SHEET BY TREATMENT THEREOF WITH ALTERNATING CURRENT IN AN AQUEOUS ELECTROLYTIC SOLUTION COMPRISED OF FROM 20 TO ABOUT 50 PERCENT BY WEIGHT OF PHOSPHATE ELECTROLYTE SELECTED FROM THE GROUP CONSISTING OF ALKALI PHOSPHATES, ALKALINE EARTH PHOSPHATES, AMMONIUM PHOSPHATE AND PHOSPHORIC ACID, AND WHEREIN THE ALTERNATING CURRENT DENSITY IS FFROM ABOUT 10 TO 200 AMPERES PER SQUARE FOOT; SAID ETCHING SUFFICIENT TO INCREASE THE FINAL SURFACE REFLECTANCE OF SAID ALUMINUM SHEET BY AT LEAST ABOUT 5 PERCENT; AND C. ANODIZING SAID ETCHED ALUMINUM SHEET BY TREATMENT WITH DIRECT CURRENT IN AN AQUEOUS ELECTROLYTE SOLUTION COMPRISED OF FROM 8 TO 22 PERCENT BY WEIGHT OF SULFURIC ACID, AND WHEREIN THE DIRECT CURRENT VOLTAGE IS FROM 10 TO 25 VOLTS, AND THE CURRENT DENSITY IS FROM 10 TO 20 AMPERES PER SQUARE FOOT, TO PROVIDE A HARD, ABRASION RESISTANT, POROUS SURFACE ON SAID ALUMINUM SHEET.
Claim 3
Dependent Claim
15 words
The method of claim 1, wherein in step b., the phosphate electrolyte is phosphoric acid.
Claim 4
Dependent Claim
16 words
The method of claim 1, wherein in step a., the wet mass is comprised of pumice.
Claim 5
Dependent Claim
34 words
The method of claim 1, wherein in step a., the fine, hard, abrasive particles are selected from the group consisting of silicon dioxide, aluminum silicate, potassium silicate, sodium silicate, aluminum oxide and magnesium sulfate.
Claim 6
Dependent Claim
29 words
The method of claim 1, wherein in step b., the phosphate electrolyte is phosphoric acid and is present in a concentration of from about 20 to 25 percent weight.
Claim 7
Dependent Claim
30 words
A lithographic printing plate which comprises an aluminum base sheet prepared according to the process of claim 1, and having a light sensitive coating applied to the treated surface thereof.
Claim 8
Dependent Claim
15 words
The lithographic plate of claim 6, wherein the light sensitive coating includes a diazo compound.
Claim 9
Dependent Claim
21 words
The method of claim 1, wherein in step c., the temperature of the solution is maintained at from 20* to 25*C.
Claim 10
Dependent Claim
22 words
The method of claim 1, wherein in step b., the electrolyTe solution is maintained at a temperature of from 40* to 60*C.
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) | 1978-12-29 | 1979-06-30 | 1979-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-29 | 1983-06-30 | 1983-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-29 | 1987-06-30 | 1987-12-30 | $7700.00 | Window Closed / Lapsed |