Lithographic printing plate support
AssigneeAgfa Graphics NV
InventorsDirk Verdyck, Paola Campestrini, Marc De Temmerman
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Abstract
A method for making a lithographic printing plate support is disclosed comprising the steps of: (i) providing an aluminum support; (ii) treating said support in an aqueous solution; (iii) graining said treated support in an electrolyte solution by applying an alternating voltage thereby inducing a local current density J; characterized in that said local current density J at time t fulfills the following equation: J(t)≦α+bQ(t) for t=o to t=tf and wherein Q(t) is the integrated value of the absolute value of the local current density at time t:(I)—a is equal to 5—b is equal to 10—and tf is the time necessary to obtain a value of Q(t) equal to 50 C/dm2. Q ( t ) = ∫ 0 t J ( τ ) τ
Claims37
A method for making a lithographic printing plate support comprising the steps of
- (i) providing an aluminum support;
- (ii) treating said support in an aqueous solution;
- and
- (iii) graining said treated support in an electrolyte solution by applying an alternating voltage to said support thereby inducing a local current density (J) at the surface of said support, wherein said local current density J at time (t) fulfills the following equation:
- J(t)≦α+bQ(t)
- for t=0 to t=tf
- and wherein in the equation
- Q(t) is the integrated value of the absolute value of the local current density J(t) at time t:
- Q
-
- (
- t
- )
- =
- ∫
- 0
- t
-
-
- J
-
- (
- τ
- )
-
-
-
- τ
- a is 5, 3.5 or 2.9,
- b is 10, 9.0 or 8.6, and
- tf is the time necessary to obtain a value of Q(t) equal to 80 50 or 10 C/dm2.
(canceled)
A method for making a lithographic printing plate support comprising the steps of:
- (i) providing an aluminum support;
- (ii) treating said support in an aqueous solution;
- and
- (iii) graining said treated support in an electrolyte solution by applying an alternating voltage to said support thereby inducing a local current density (J) at the surface of said support, wherein said local current density J at time (t) fulfills the following equation:
- J(t)≦α+bQ(t)
- for t=0 to t=tf
- and wherein in the equation
- Q(t) is the integrated value of the absolute value of the local current density J(t) at time t:
- Q
-
- (
- t
- )
- =
- ∫
- 0
- t
-
-
- J
-
- (
- τ
- )
-
-
-
- τ
- a is 5, 3.5 or 2.9,
- b is ≦8.6, and
- tf is the time necessary to obtain a value of Q(t) equal to 80, 50 or 10 C/dm2.
Dependencies are inferred from the claim text.