US4427500A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing an aluminum support useful for lithography
Assignee: CNA Holdings LLC
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Filing: 1982-03-15
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Granted: 1984-01-24
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Expires: 2002-03-15
Abstract
Abstract An improved substrate suitable for use as a base for a lithographic printing plate, especially a plate useful for the production of continuous tone images. The substrate is produced by extremely uniformly graining an aluminum sheet which has a highly polished, mirror-like surface.
Inventors
- 👤 Stephan J. Platzer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 05:46
CPC Classifications
B; B41; B41N; B41N3/00; B41N3/03; Y; Y10; Y10S; Y10S205/00; Y10S205/921
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
168 words
A method for producing a substrate for a lithographic printing plate from an aluminum or aluminum alloy sheet which comprises treating at least a portion of the surface of said sheet so as to impart to it a perpendicular center-line roughness value (R) of ≦0.10μ and then graining said portion such that the surface which has been grained comprises pits and: (i) a distribution of pit diameters such that the arithmetic mean of the pit diameters (Da) is in the range of about 0.5≦Da≦4.0μ; and (ii) at least about 99% of all pits have a diameter (D99)≦10μ; and (iii) a pit diameter directionality (Dd)≦about 10%; and (iv) a total non-pitted surface area (A) of said plate having either no pits or pits with a diameter of less than or equal to 0.5μ, of less than about 20% of said surface area; and (v) a center-line average roughness (Ra) of said surface in the range of from about 0.2 to about 1.4μ; and (vi) a roughness directionality (Rd)≦about 10%.
Claim 2
Independent Claim
168 words
A method for producing a substrate for a lithographic printing plate from an aluminum or aluminum alloy sheet which comprises treating at least a portion of the surface of said sheet so as to impart to it a perpendicular center-line roughness value (R) of ≦0.10μ and then graining said portion such that the surface which has been grained comprises pits and: (i) a distribution of pit diameters such that the arithmetic mean of the pit diameters (Da) is in the range of about 0.5≦Da≦4.0μ; and (ii) at least about 99% of all pits have a diameter (D99)≦10μ; and (iii) a pit diameter directionality (Dd)≦about 10%; and (iv) a total non-pitted surface area (A) of said plate having either no pits or pits with a diameter of less than or equal to 0.5μ, of less than about 20% of said surface area; and (v) a center-line average roughness (Ra) of said surface in the range of from about 0.2 to about 1.4μ; and (vi) a roughness directionality (Rd)≦about 10%.
Claim 3
Dependent Claim
15 words
The method of claim 1 further comprising the subsequent step of anodizing said grained substrate.
Claim 4
Dependent Claim
15 words
The method of claim 1 further comprising the subsequent step of hydrophilizing the grained surface.
Claim 5
Dependent Claim
15 words
The method of claim 2 further comprising the subsequent step of hydrophilizing said anodized surface.
Claim 6
Dependent Claim
29 words
The method of claim 1, 2, 3, or 4 further comprising the step of applying a lithographic photosensitive composition to at least a portion of said treated support surface.
Claim 7
Dependent Claim
19 words
The method of claim 5 wherein said lithographic photosensitive composition comprises a material capable of producing continuous tone images.
Claim 8
Dependent Claim
12 words
The method of claim 6 wherein said photosensitive composition is positive working.
Claim 9
Dependent Claim
24 words
The method of claim 6 wherein said photosensitive composition comprises a compound selected from the group consisting of diazonium salts, diazides, azides and photopolymers.
Claim 10
Dependent Claim
29 words
The method of claim 8 wherein said photosensitive composition further comprises one or more ingredients selected from the group consisting of binding resins, uv absorbers, colorants, solvents and plasticizers.
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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) | 1987-01-23 | 1987-07-25 | 1988-01-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-23 | 1991-07-25 | 1992-01-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-23 | 1995-07-25 | 1996-01-24 | $7700.00 | Window Closed / Lapsed |