US 6,485,890 B2Granted

Lithographic printing forms

AssigneeKodak Polychrome Graphics LLC

InventorsGareth Rhodri Parsons, David Stephen Riley, Richard David Hoare, Alan Stanley Victor Monk

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Abstract

Thermally imageable lithographic printing plate precursors and heat-sensitive compositions for use in these printing plate precursors are disclosed. The compositions contain an aqueous developer soluble polymer, such as a phenolic resin; a compound that reduces the aqueous developer solubility of the polymer; and optionally, and infrared absorber. Examples of compounds that reduce the aqueous developer solubility of the polymer are those that contain at least one quarternized nitrogen atom, such as quinolinium compounds, benzothiazolium compounds, pyridinium compounds, and imidazoline compounds. On thermal imaging, the irradiated areas become more soluble in the aqueous developer and can be removed to form a positive image.

Claims64

Dependent claims

A method of producing a lithographic printing form, the method comprising:

(A) imagewise applying heat to a positive-working lithographic printing form precursor comprising a coating, the coating comprising a positive-working, oleophilic, heat sensitive composition coated on a support having a hydrophilic surface, the coated composition comprising:
an aqueous alkaline developer soluble polymeric substance;
and
a compound which reduces the aqueous alkaline developer solubility of the polymeric substance;
wherein
(i) the composition when coated onto the hydrophilic substrate and processed in an aqueous alkaline developer does not substantially dissolve in the aqueous alkaline developer;
(ii) the aqueous alkaline developer solubility of the composition is increased by heating;
and
(iii) the aqueous alkaline developer solubility of the composition is not increased by incident ultraviolet radiation;
and
(B) applying the aqueous alkaline developer to the precursor, wherein portions of the coated composition where the heat was applied are dissolved.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/860,943Filed 18 May 2001 · division
Priority: GB 960839423 Apr 1996
Published: US 2002/0045124 A118 Apr 2002
Granted: 26 Nov 2002
Term ends: Not estimatedThe source records don’t support an estimate.

Classification15 codes

B41M 5/368
Using a polymeric layer, which may be particulate and which is deformed or structurally changed with modification of its' properties, e.g. of…
B41C 1/1008
For lithographic printing; Master sheets for transferring a lithographic image to the forme: by removal or destruction of lithographic material on…
B41C 1/1016
By removal or destruction of lithographic material on the lithographic support, e.g. by laser or spark ablation; by the use of materials…
B41C 2210/02
Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation: positive working, i.e. the…

Family

PCT/GB97/01117Parent of this division · filed 22 Apr 1997
Application09/483,990Parent of this division · filed 18 Jan 2000
US 6,280,899 B1Parent of this division · filed 28 Aug 2001
US 2002/0045124 A1Pre-grant publication · published 18 Apr 2002
Application08/981,620Parent of this division
US 6,485,890 B2This patent

From the US filing history. Foreign family members aren’t listed.