US3873318A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of lithographic plates
Assignee: Alcan Research and Development Ltd
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Filing: 1973-06-01
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Granted: 1975-03-25
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Expires: 1993-06-01
Abstract
Abstract A method of preparing aluminium for use in the production of lithographic plates in which after an optional electrolytic or mechanical treatment the aluminium in continuous strip form is subjected to anodisation to develop a soft, porous, flexible, anodic oxide coating having a thickness in the range of 0.1 - 1 micron, said anodisation being performed during the passage of said strip through an aqueous sulphuric acid anodisation electrolyte held at a temperature above 70*C, said strip being subjected during passage through said electrolyte to an electrolytic treatment for a period of 10 - 60 seconds and involving a charge input of at least 500 coulombs/sq.ft. preferably 1,500 - 5,000 coulombs/sq.ft.
Inventors
- 👤 Peter Geoffrey Sheasby
- 👤 Alan Martin Smith
- 👤 Christopher Robert Gilkes
- 👤 Wolf Dieter Breit
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:07
CPC Classifications
B; B41; B41N; B41N3/00; B41N3/03; B41N3/034; C; C25; C25D; C25D11/00; C25D11/02; C25D11/04; C25D11/024; Y; Y10; Y10S; Y10S430/00; Y10S430/136
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
122 words
A METHOD OF PREPARING ALUMINUM FOR USE IN THE PRODUCTION OF LITHOGRAPHIC PLATES IN WHICH AFTER AN OPTICAL ELECTRLYTIC OR MECHANICAL TREATMENT THE ALUMINIUM IN CONTINUOUS STRIP FROM IS SUBJECTED TO ANODISATION TO DEVELOP A SOFT, POROUS, FLEXIBLE, ANODIC OXIDE COATING HAVING A THICKNESS IN THE RANGE OF 0.1 - 1 MICRON AND ESSENTIALLY FREE OF PITS IN A SIZE RANGE OF 0.03 - 0.04 MICRON, SAID ANODISATION BEING PERFORMED DURING THE PASSAGE OF SAID STRIP THROUGH AN AQUEOUS SULPHURIC ACID ANODISATION ELECTROLYTE HELD AT A TEMPERATURE ABOVE 70*C, SAID STRIP BEING SUBJECTED DURING PASSAGE THROUGH SAID ELECTROLYTE TO AN ELECTROLYTIC TREATMENT FOR A PERIOD OF 10 - 60 SECONDS AND INVOLVING A CHARGE INPUT OF AT LEAST 500 COULOMBS SQ. FT.
Claim 2
Independent Claim
122 words
A METHOD OF PREPARING ALUMINUM FOR USE IN THE PRODUCTION OF LITHOGRAPHIC PLATES IN WHICH AFTER AN OPTICAL ELECTRLYTIC OR MECHANICAL TREATMENT THE ALUMINIUM IN CONTINUOUS STRIP FROM IS SUBJECTED TO ANODISATION TO DEVELOP A SOFT, POROUS, FLEXIBLE, ANODIC OXIDE COATING HAVING A THICKNESS IN THE RANGE OF 0.1 - 1 MICRON AND ESSENTIALLY FREE OF PITS IN A SIZE RANGE OF 0.03 - 0.04 MICRON, SAID ANODISATION BEING PERFORMED DURING THE PASSAGE OF SAID STRIP THROUGH AN AQUEOUS SULPHURIC ACID ANODISATION ELECTROLYTE HELD AT A TEMPERATURE ABOVE 70*C, SAID STRIP BEING SUBJECTED DURING PASSAGE THROUGH SAID ELECTROLYTE TO AN ELECTROLYTIC TREATMENT FOR A PERIOD OF 10 - 60 SECONDS AND INVOLVING A CHARGE INPUT OF AT LEAST 500 COULOMBS SQ. FT.
Claim 3
Dependent Claim
26 words
A method according to claim 1 in which the charge input during the electrolytic anodisation treatment is in the range of 1,500 - 5,000 coulombs/sq. ft.
Claim 4
Independent Claim
140 words
A method of producing lithographic plates which comprises subjecting aluminium in continous strip form to aNodisation, after an optional electrolytic or mechanical roughening treatment, to develop a soft, porous, flexible, anodic oxide coating having a thickness in the range of 0.1 - 1 micron and essentially free of pits in a size range of 0.03 - 0.04 micron, said anodisation being performed during the passage of said strip through an aqueous sulphuric acid anodisation electrolyte held at a temperature above 70*C, said strip being subjected during passage through said electrolyte to an electrolytic treatment for a period of 10 - 60 seconds and involving a charge input of at least 500 coulombs/sq. ft., and applying to said anodic oxide coating a light-sensitive coating of a type which changes between a hydrophobic state and a hydrophilic state on exposure to light.
Claim 5
Independent Claim
140 words
A method of producing lithographic plates which comprises subjecting aluminium in continous strip form to aNodisation, after an optional electrolytic or mechanical roughening treatment, to develop a soft, porous, flexible, anodic oxide coating having a thickness in the range of 0.1 - 1 micron and essentially free of pits in a size range of 0.03 - 0.04 micron, said anodisation being performed during the passage of said strip through an aqueous sulphuric acid anodisation electrolyte held at a temperature above 70*C, said strip being subjected during passage through said electrolyte to an electrolytic treatment for a period of 10 - 60 seconds and involving a charge input of at least 500 coulombs/sq. ft., and applying to said anodic oxide coating a light-sensitive coating of a type which changes between a hydrophobic state and a hydrophilic state on exposure to light.
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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) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |