Printing form precursors
AssigneeKodak Polychrome Graphics LLC
InventorsMaru Aburano, Shoichi Hotate, Shinji Shimizu, Yasuhiko Kojima
Life of this patent
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Abstract
Lithographic printing form precursors comprising positive working polymeric coatings on substrates may during storage or transportation undergo undesirable changes in their imaging properties. It has been found that acceptable properties can be restored by carrying out a heat treatment which involves a relatively short heating stage followed by accelerated cooling.
Claims22
A method of preparing a printing form precursor or precursor web comprising:
- (a) providing an imageable coating on a substrate, wherein the coating comprises a positive working polymeric composition;
- (b) subjecting the precursor to a heat treatment at an elevated temperature;
- and
- (c) accelerating the cooling of the precursor.
A method of reclaiming a precursor having a defective imageable coating on a substrate, the coating comprising a positive working polymeric composition, wherein the method comprises subjecting the precursor to an elevated temperature followed by accelerating cooling of the precursor.
A method of improving the imaging characteristics of a thermally imageable lithographic printing form precursor having degraded imaging characteristics, the method comprising:
- (a) heating the thermally imageable precursor to an elevated temperature in the range 45-110° C.;
- and
- (b) accelerating the cooling of the heated precursor to 30° C. or below.
A method of treatment of a printing form precursor, the method comprising:
- (a) providing a precursor comprising a heat imageable coating on a substrate, the coating comprising a positive working polymeric composition which comprises a polymer having hydroxyl groups, an insolubilizer which acts to inhibit the dissolution of the coating in a developer prior to heat imaging but not after heat imaging, and a radiation absorbing compound able to absorb electromagnetic radiation in the range 600 to 1400 nm and convert the radiation to heat;
- (b) heating the precursor, in the form of an individual precursor or a precursor web or in a packet, such that the precursor is subjected to an elevated temperature for a period not exceeding 5 hours;
- and
- (c) accelerating cooling of the precursor to bring the precursor temperature to 30° C. or below in less than 1 hour.
A method of treatment of a printing form precursor included in a stack, the method comprising:
- (a) providing a stack comprising at least one precursor having a heat imageable coating on a substrate, the coating comprising a positive working polymeric composition which comprises a polymer having hydroxyl groups, an insolubilizer which acts to inhibit the dissolution of the coating in a developer prior to heat imaging but not after heat imaging, and a radiation absorbing compound able to absorb electromagnetic radiation in the range 600 to 1400 nm and convert the radiation to heat;
- (b) subjecting the stack to an elevated temperature for a period not exceeding 8 hours;
- and
- (c) accelerating the cooling of the stack to bring the stack temperature to 30° C. or below over a period not exceeding 8 hours.
A positive working lithographic printing form precursor produced by a method comprising:
- (a) providing an imageable coating on a substrate, wherein the coating comprises a positive working polymeric composition;
- (b) subjecting the precursor to a heat treatment at an elevated temperature;
- and
- (c) accelerating the cooling of the precursor.
A method of producing a lithographic printing form bearing a pattern in a coating thereon, the method comprising:
- (I) preparing a precursor by a method comprising:
- (a) providing an imeagable coating on a substrate, wherein the coating comprises a positive working polymeric composition,
- (b) subjecting the precursor to a heat treatment at an elevated temperature, and
- (c) accelerating the cooling of the precursor;
- (II) imagewise exposing the coating of the precursor;
- and
- (III) contacting the exposed coating with an aqueous developer thereby removing imagewise exposed regions of the coating.
A lithographic printing form, produced by a method of comprising:
- (I) preparing a precursor by a method comprising:
- (a) providing an imeagable coating on a substrate, wherein the coating comprises a positive working polymeric composition,
- (b) subjecting the precursor to a heat treatment at an elevated temperature, and
- (c) accelerating the cooling of the precursor;
- (II) imagewise exposing the coating of the precursor;
- and
- (III) contacting the exposed coating with an aqueous developer thereby removing imagewise exposed regions of the coating.
Dependencies are inferred from the claim text.