Abstract:
An imageable element useful as a flexographic printing plate precursor is disclosed. The element is made up of a flexible substrate; a photosensitive layer, which contains a negative working photosensitive composition; an optional barrier layer; and a masking layer. The masking layer is thermally bleachable, comprises a dye that typically has an absorption maximum between about 250 nm and about 600 nm, more typically between about 300 nm and about 500 nm, and is substantially free of photothermal conversion materials.
Abstract:
The use of certain mercapto compounds as shelf life improvers for infrared-sensitive lithographic printing plate precursors is disclosed. The compounds are five-membered heteroaromatic rings containing a nitrogen atom and at least one other heteroatom, which can be oxygen, sulfur, or another nitrogen atom, such that two ring heteroatoms are bonded to a ring carbon bearing a thiol group.
Abstract:
Disclosed is a thermally sensitive imagable article and compositions therefor. The imagable article comprises a coating on a substrate, the coating comprising an amino acid or amide, and a compound capable of generating an acid upon heating. The coating optionally comprises a radiation absorbing compound. When imagewise exposed the coating has the property that exposed regions become relatively insoluble in a developer liquid whereas regions that have not been exposed remain relatively soluble in the developer and dissolve in the developer, leaving the exposed substrate in those regions.
Abstract:
A lithographic printing plate substrate is conditioned for imaging in a printer engine by attaching a leader to the leading edge. The leader is sufficiently flexible to be drawn into the printer engine and is adapted to pull the plate substrate through the printer engine.
Abstract:
A negative-working image forming process which comprises the steps of: (1) flood exposing with actinic radiation a photosensitive assembly that comprises: (a) a hydrophilic support which can be used as a lithographic base and having thereon; (b) a first layer comprising: (i) at least one polymer that is soluble or dispersible in an aqueous alkaline solution; (c) a second layer on top of the first layer, the second layer comprising at least one o-quinonediazide compound; whereby the flood exposure causes the at least one o-quinonediazide compound to be converted to the corresponding indenecarboxylic acid compound; and (d) at least one photothermal conversion material in either the first layer or the second layer or both; (2) imagewise exposing the flood exposed photosensitive assembly with infrared radiation to thereby convert the indenecarboxylic acid compound in the second layer in the imagewise exposed areas to the corresponding indene compound; and (3) developing the imagewise exposed photosensitive assembly with an alkaline developing solution to dissolve out the imagewise unexposed areas of the second layer and the areas of the first layer underlying the imagewise unexposed areas of the second layer and thereby produce a negative working image.
Abstract:
A method for producing printing plate precursors by dual-feed technology is described. The obtained printing plate precursors contain polymer particles in the photosensitive layer and show high print run stability.
Abstract:
A lithographic printing plate substrate is conditioned for imaging in a printer engine by attaching a leader to the leading edge. The leader is sufficiently flexible to be drawn into the printer engine and is adapted to pull the plate substrate through the printer engine.
Abstract:
Polymeric compounds for lithographic printing plates, especially plates for use in printing utilizing UV curable inks, may include a structural unit (I) 1 wherein R1 represents an optionally-substituted cyclic or alkyl group, x represents 0 or 1 and A represents an optionally-substituted alkylene group. A range of compounds having different solubilities in selected solvents may be prepared by varying the identity or group R1. Such components may be prepared by reacting an amine of formula R1NH2 with the maleic anhydride derivative corresponding to moiety 1.
Abstract:
An imaging member is prepared by applying to a support a heat-sensitive imaging layer which comprises at least one heat-sensitive polymer capable of undergoing transformation from a hydrophilic to hydrophobic state or hydrophobic to hydrophilic state, wherein the transformation occurs such that the activation energy Ea and the Arrhenius pre-exponential factor A associated with the transformation simultaneously fulfill the relationships: ln (A).gtoreq.0.4 Ea+8.84 and ln (A).ltoreq.1.69 Ea-14.37. The imaging member is useful in processless thermal lithographic printing.
Abstract:
A planographic printing plate includes a radiation sensitive layer which may comprise a rubber material. Application of heat causes exposed areas to be vulcanized. The plate may be developed by applying a force to the radiation sensitive layer, for example by rubbing, thereby to remove non-exposed areas.