Abstract:
To provide a coloring photosensitive composition and a lithographic printing plate precursor, ensuring that coloring stability after exposure by infrared laser exposure is good and high coloring is obtained even when exposed after the elapse of time. These can be a coloring photosensitive composition containing a microgel encapsulating (A) a polymer having a glass transition temperature of 50° C. or more, (B) a photoinitiator, and (C) an infrared absorbing dye, and a lithographic printing plate precursor having an image-recording layer containing the composition.
Abstract:
The lithographic printing plate support includes an aluminum plate and an anodized film formed on the aluminum plate and micropores extend in the anodized film in a depth direction from its surface opposite from the aluminum plate. Each of the micropores includes a large-diameter portion having a predetermined shape and a small-diameter portion having a predetermined shape. The lithographic printing plate support has excellent scratch resistance and is capable of obtaining a presensitized plate which exhibits excellent on-press developability and enables a lithographic printing plate formed therefrom to have a long press life, and excellent deinking ability in continued printing and after suspended printing.
Abstract:
A lithographic printing plate precursor comprising a coating provided on a support having a hydrophilic surface, the coating containing thermoplastic polymer particles and an IR-dye characterized in that the IR-dye contains a structural element according to Formula I wherein A represents hydrogen, halogen or a monovalent organic group; Y and Y′ independently represent —CH— or —N—; R1 and R2 independently represent hydrogen, an optionally substituted alkyl or aryl group or represent the necessary atoms to form a ring; * represents the linking positions to the rest of the molecule.
Abstract:
A lithographic printing plate precursor includes, in the following order: a support; an image-recording layer which is capable of forming an image by removing an unexposed area by an automatic development processor in the presence of a developer having pH of from 2 to 14 after exposure and contains (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound and (D) a polymer which is insoluble in water and alkali-soluble; and a protective layer, and the protective layer contains (E) a hydrophilic polymer which has a repeating unit represented by the formula (1) as defined herein and a repeating unit represented by the formula (2) as defined herein and a sum of the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2) is at least 95% by mole based on total repeating units constituting the polymer.
Abstract:
On-press developable, negative-working lithographic printing plate precursors have a sulfuric acid anodized aluminum-containing substrate in which the oxide layer pores have been widened using an acidic or alkaline treatment. Over the widened pores, a hydrophilic coating is applied, which coating comprises a non-crosslinked hydrophilic polymer having carboxylic acid side chains. This particular substrate provides improved adhesion and printing durability for on-press development and printing.
Abstract:
A lithographic printing plate precursor which is excellent in both the on-press development property and the printing durability and which is excellent particularly in the on-press development property after preservation for a long period of time, wherein the lithographic printing plate precursor includes an intermediate layer containing a polymer compound including a repeating unit (a1) having a support-adsorbing group and a repeating unit (a2) having a polyoxyalkylene group having a repeating number of oxyalkylene units from 8 to 120 between a support and a polymerizable image-recording layer, and contains a compound having a molecular weight of 1,500 or less and having an oxyalkylene group in at least any of the intermediate layer and the polymerizable image-recording layer.
Abstract:
A negative-working lithographic printing plate precursor comprises a negative-working radiation-sensitive imageable layer and an outermost layer comprising a vinyl alcohol copolymer comprising at least one unit of each of the (a), (b), and (c) recurring units, in any order, defined in the disclosure. The (c) recurring units are present in the vinyl alcohol copolymer in an amount of at least 0.5 mol %, based on the total recurring units. These precursors can be used to prepare lithographic printing plates either on-press or off-press after imaging using near-UV, visible, or infrared radiation.
Abstract:
A method for making a lithographic printing plate precursor is disclosed comprising the steps of a. providing a lithographic printing plate precursor including a support having a hydrophilic surface or which is provided with a hydrophilic layer, a photopolymerizable coating comprising a photopolymerizable composition, and an overcoat layer comprising a water soluble low molecular weight acid, wherein said overcoat layer has a surface pH-value ranging between 1 to 6; b. image-wise exposing the precursor; c. optionally heating the exposed precursor; d. processing the obtained precursor by applying a gum solution and optionally brushing the precursor, and/or by mounting the precursor on a plate cylinder of a lithographic printing press and rotating the plate cylinder while feeding dampening liquid and/or ink to the coating. The printing plate obtained after imaging and processing in an off-press configuration with a gum solution or in an on-press configuration with fountain solution and ink shows an improved roll-up performance in the start-up of a printing process on a printing press.
Abstract:
A process for making a lithographic printing plate, comprising: an exposure step of imagewise exposing a lithographic printing plate precursor that comprises, above a hydrophilic support, a photosensitive layer comprising (A) a compound that generates a radical upon the application of light or heat, (B) a polymer having an aromatic carboxy group in a side chain, (C) a polymerizable compound, and (D) an infrared absorber; and a development processing step using one type of processing liquid, wherein the processing liquid has a pH of 8.5 to 10.8.
Abstract:
A method for making a positive-working lithographic printing plate includes the steps of: (1) providing a heat-sensitive printing plate precursor including on a support, having a hydrophilic surface or which is provided with a hydrophilic layer, a heat-sensitive coating; (2) image-wise exposing the precursor with heat and/or light; and (3) developing the exposed precursor with an aqueous alkaline developing solution including lithium ions at a concentration of at least 0.05% wt and a salt of an aliphatic carboxylic acid; wherein the molar ratio of the aliphatic carboxylic acid to the lithium ions is ≧1.