US3881998A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of after-treatment for lithographic printing plates
Assignee: Kansai Paint Co Ltd
•
Filing: 1973-07-23
•
Granted: 1975-05-06
•
Expires: 1993-07-23
Abstract
Abstract This invention relates to a method of after-treatment for lithographic printing plates having an aluminum substratum in order to impart an extended durability for offset printing which comprises passing an electric current through the surface of the non-image area of the aluminum substratum and a counter electrode, particularly with a trend of increasing electric voltage in course of time, in an aqueous solution of oxyacid salt or oxyacid salts after forming a printing element which is oleophilic and electrically non-conductive on the image area of the surface of the aluminum substratum and, if necessary, further processing with an aqueous solution of acid or salt.
Inventors
- 👤 Yushiaki Miyosawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:21
CPC Classifications
B; B41; B41C; B41C1/00; B41C1/10; B41N; B41N3/00; B41N3/08
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
115 words
A METHOD OF AFTER-TREATMENT FOR LITHOGRAPHIC PRINTING PLATES HAVING AN ALUMINUM SUBSTRATUM FOR PRODUCING A HYDROPHILIC CHEMICAL CONVERSION COATING ON THE NON-IMAGE AREAS THEREOF, WHEREIN SAID PRINTING PLATES HAVE AN OLEOPHILIC AND ELECTRICALLY NON-CONDUCTIVE IMAGE AREAS ON THE SURFACE OF SAID ALUMINUM SUBSTRATUM, WHICH COMPRISES PASSING ELECTRIC CURRENT THROUGH THE SURFACE OF THE NON-IMAGE AREA OF SAID ALUMINUM SUBSTRATUM BY APPLYING AN ELECTRIC VOLTATGE BETWEEN SAID ALUMINUM SUBSTRATUM AND A COUNTER ELECTRODE IN AN AQUEOUS SOLUTION OF AT LEAST ONE WATER-SOLUBLE OXYACID SALT SELECTED FROM THE GROUP CONSISTING OF SILICATES, CHROMATES, STANNATES, MOLYBDATES, PHOSPHOMOLYBDATES, TUNGSTATES, VANADATES, BORATES AND PHOSPHATES OF LITHIUM, SODIUM, POTASSIUM, AMMONIUM AND ALUMINUM, (NH4)4W5O17, (NH4)6W7O24, NA3PO4.12WO3, BA(B(W2O7)6), NA2B10O16, NABO2.H2O2, NAH2BO3.2HCOOH AND (NH4)HB4O7.
Claim 2
Independent Claim
115 words
A METHOD OF AFTER-TREATMENT FOR LITHOGRAPHIC PRINTING PLATES HAVING AN ALUMINUM SUBSTRATUM FOR PRODUCING A HYDROPHILIC CHEMICAL CONVERSION COATING ON THE NON-IMAGE AREAS THEREOF, WHEREIN SAID PRINTING PLATES HAVE AN OLEOPHILIC AND ELECTRICALLY NON-CONDUCTIVE IMAGE AREAS ON THE SURFACE OF SAID ALUMINUM SUBSTRATUM, WHICH COMPRISES PASSING ELECTRIC CURRENT THROUGH THE SURFACE OF THE NON-IMAGE AREA OF SAID ALUMINUM SUBSTRATUM BY APPLYING AN ELECTRIC VOLTATGE BETWEEN SAID ALUMINUM SUBSTRATUM AND A COUNTER ELECTRODE IN AN AQUEOUS SOLUTION OF AT LEAST ONE WATER-SOLUBLE OXYACID SALT SELECTED FROM THE GROUP CONSISTING OF SILICATES, CHROMATES, STANNATES, MOLYBDATES, PHOSPHOMOLYBDATES, TUNGSTATES, VANADATES, BORATES AND PHOSPHATES OF LITHIUM, SODIUM, POTASSIUM, AMMONIUM AND ALUMINUM, (NH4)4W5O17, (NH4)6W7O24, NA3PO4.12WO3, BA(B(W2O7)6), NA2B10O16, NABO2.H2O2, NAH2BO3.2HCOOH AND (NH4)HB4O7.
Claim 3
Dependent Claim
56 words
A method of after-treatment for lithographic printing plates as claimed in claim 1, in which the concentration of said chromates, stannates, molybdates, phosphomolybdates, tungstates, vanadates, borates or phosphates of lithium, sodium, potassium, ammonium or aluminum, (NH4)4W5O17, (NH4)6W7O24, Na3PO4.12WO3 Ba(B(W2O7)6), Na2B10O16, NaBO2.H2O2, NaH2BO3.2HCOOH and (NH4)HB4O7 in said aqueous solution is from 1 % by weight to saturation.
Claim 4
Dependent Claim
34 words
A method of after-treatment for lithographic printing plates as claimed in claim 1, in which said electric current has a current density not exceeding 10 amperes/dm2 of said non-image area of said aluminum substratum.
Claim 5
Dependent Claim
35 words
A method of after-treatment for lithographic printing plates as claimed in claim 1, in which the integrated amount of said electric current is not below 10 coulombs/dm2 of said non-image area of said aluminum substratum.
Claim 6
Dependent Claim
48 words
A method of after-treatment for lithographic printing plates as claimed in claim 1, in which said electric current has a current density not exceeding 10 amperes/dm2 and the integrated amount of said electric current is not below 10 coulombs/dm2 of said non-image area of said aluminum substratum, respectively.
Claim 7
Dependent Claim
29 words
A method of after-treatment for lithographic printing plates as claimed in claim 1, in which said electric voltage is an alternating electric voltage of from 5 to 80 volts.
Claim 8
Dependent Claim
29 words
A method of after-treatment for lithographic printing plates as claimed in claim 1, in which said electric voltage is a direct electric voltage of from 5 to 150 volts.
Claim 9
Dependent Claim
30 words
A method of after-treatment for lithographic printing plates as claimed in claim 1, in which said electric voltage is increased from lower voltage to higher voltage during the application thereof.
Claim 10
Dependent Claim
64 words
A process of after-treatment for lithographic printing plates having an aluminum substratum as claimed in claim 1 wherein the resulting lithographic printing plates are contacted with an aqueous solution of an acid or salt selected from the group consisting of acetic acid, crotonic acid, oxalic acid, hydroxyacetic acid, citric acid, tartaric acid, gluconic acid, phosphoric acid, ammonium chloride, calcium nitrate, and monobasic ammonium phosphate.
Claim 11
Dependent Claim
20 words
A method of after-treatment for lithographic printing plates as claimed in claim 1 wherein said oxyacid salt is sodium silicate.
Claim 12
Dependent Claim
26 words
A method of after-treatment for lithographic printing plates as claimed in claim 1 wherein said oxyacid salt is a mixture of sodium silicate and potassium metaborate.
Claim 13
Dependent Claim
20 words
A method of after-treatment for lithographic printing plates as claimed in claim 1 wherein said oxyacid salt is Al (H2PO4)3.
Claim 14
Dependent Claim
38 words
A method of after-treatment for lithographic printing plates as claimed in claim 1, in which the concentration of said silicates of lithium, sodium, potassium and ammonium in said aqueous solution is form 5 to 40 % by weight.
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) | 1978-05-05 | 1978-11-04 | 1979-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-05 | 1982-11-04 | 1983-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-05 | 1986-11-04 | 1987-05-06 | $7700.00 | Window Closed / Lapsed |