US4545875A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrolytic graining
Assignee: Polychrome Corp
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Filing: 1984-08-06
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Granted: 1985-10-08
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Expires: 2004-08-06
Abstract
Abstract The invention features an electrolytic process for producing lithographic plates. The plates are immersed in a bath and fed a shaped alternating wave having a multiplicity of zero voltage intermissions. The grain topography of the plate can be varied by changing the frequency and duration of the intermissions in the wave.
Inventors
- 👤 Donald J. Riley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:10
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: 6
Claim 1
Independent Claim
59 words
In the method for preparing a grained aluminum support for lithographic printing plates comprising the treatment of an aluminum plate disposed within an electrolytic bath to a shaped alternating current, the improvement which comprises utilizing a shaped alternating current having a wave form that includes multiple zero voltage intermissions in both cathode and anode phases of said wave form.
Claim 2
Dependent Claim
59 words
In the method for preparing a grained aluminum support for lithographic printing plates comprising the treatment of an aluminum plate disposed within an electrolytic bath to a shaped alternating current, the improvement which comprises utilizing a shaped alternating current having a wave form that includes multiple zero voltage intermissions in both cathode and anode phases of said wave form.
Claim 3
Dependent Claim
20 words
In the method of claim 1, wherein modification of grain topography occurs by adjusting the frequency of said multiple intermissions.
Claim 4
Dependent Claim
48 words
In the method of claim 2 wherein said wave form is applied by introducing said alternating current to said aluminum plate through a transistorized circuit, and wherein said frequency of said intermissions is adjustable by applying a given pulse signal to a gate portion of said transistorized circuit.
Claim 5
Dependent Claim
20 words
In the method of claim 1, wherein modification of grain topography occurs by adjusting the duration of said multiple intermissions.
Claim 6
Dependent Claim
25 words
In the method of claim 1 wherein said wave form is applied by introducing said alternating current to said aluminum plate through a transistorized circuit.
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) | 1988-10-07 | 1989-04-08 | 1989-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-07 | 1993-04-08 | 1993-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-07 | 1997-04-08 | 1997-10-08 | $7700.00 | Window Closed / Lapsed |