US4548683A
Expired / Lapsed
US
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Method of electrolytically graining a lithographic plate
Assignee: Polychrome Corp
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Filing: 1984-09-28
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Granted: 1985-10-22
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Expires: 2004-09-28
Abstract
Abstract A method is provided for electrolytically graining an aluminum lithographic plate to produce a grained surface with a honeycomb topography, non-directional grain structure, and a substantially reduced production of smut. The reduction of smut is achieved by utilizing an alternating current of higher frequencies, generally in the range of approximately 140 to 400 Hz.
Inventors
- 👤 Jen-Chi Huang
- 👤 Gregory Von Gruenberg
- 👤 Donald J. Riley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:09
CPC Classifications
C; C25; C25F; C25F3/00; C25F3/02; C25F3/04; B; B41; B41N; B41N3/00; B41N3/03; B41N3/034; Y; Y10; Y10S; Y10S204/00; Y10S204/09
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
91 words
In a method of electrolytically graining a surface of a lithographic plate comprising immersing said lithographic plate in an acidic bath; and subjecting said lithographic plate to an alternating current for a time period sufficient to attain said graining; the improvement which comprises utilizing an alternating current having a current density within the range of about 7 to 22 A/dm 2 , and a frequency of 140 to 400 Hz to obtain a lithographic plate surface characterized by a substantially non-directional honeycomb typography together with a substantial reduction in smut formation.
Claim 2
Dependent Claim
91 words
In a method of electrolytically graining a surface of a lithographic plate comprising immersing said lithographic plate in an acidic bath; and subjecting said lithographic plate to an alternating current for a time period sufficient to attain said graining; the improvement which comprises utilizing an alternating current having a current density within the range of about 7 to 22 A/dm 2 , and a frequency of 140 to 400 Hz to obtain a lithographic plate surface characterized by a substantially non-directional honeycomb typography together with a substantial reduction in smut formation.
Claim 3
Dependent Claim
23 words
In the method of claim 1 wherein the current density of the alternating current ranges from about 10 to 18 A/dm 2 .
Claim 4
Dependent Claim
20 words
In the method of claim 1 wherein the frequency of the alternating current is from about 160 to 300 Hz.
Claim 5
Dependent Claim
13 words
In the method of claim 1 wherein said lithographic plate comprises aluminum metal.
Claim 6
Dependent Claim
18 words
In the method of claim 1 wherein said acid bath comprises hydrochloric acid, nitric acid, or mixtures thereof.
Claim 7
Dependent Claim
20 words
In the method of claim 1 wherein said current is applied to said plate for about 5 to 300 seconds.
Claim 8
Dependent Claim
22 words
In the method of claim 1 wherein said acid bath has a temperature in the range of from 20° to 50° C.
References Cited (Backward Citations)
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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) | 1988-10-21 | 1989-04-22 | 1989-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-21 | 1993-04-22 | 1993-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-21 | 1997-04-22 | 1997-10-22 | $7700.00 | Window Closed / Lapsed |