IR-sensitive lithographic printing plate precursors provide a stable print-out image using a unique IR-sensitive image-recording layer. The IR radiation-sensitive layer includes: (1) a free radical initiator composition with an electron-donating agent and one or more iodonium cations; (2) a free radically polymerizable composition; and (3) a color-changing compound of Structure (I) having an indene ring in the conjugated chain between the aromatic terminal groups. The IR radiation-sensitive composition and layer also contains one or more borate ions such that the molar ratio of one or more borate ions to the one or more iodonium ions is at least 0.5:1. After IR imaging, these precursors exhibit desirable printout images both fresh and after dark storage. The precursors can be developed on-press.

A positive-working lithographic printing plate includes a support having a hydrophilic surface or a hydrophilic layer, and a heat- and/or light-sensitive coating provided including at least two different (ethylene vinyl) acetal copolymer including a plurality of ethylenic moieties A having a structure according to the following formula:

##STR00001##

wherein R.sup.2 and R.sup.3 independently represent hydrogen, a halogen or an optionally substituted linear, branched, or cyclic alk(en)yl group, or an optionally substituted aromatic or heteroaromatic group.

A method is disclosed in the context of a system comprises an electrophotographic subsystem, a transfer subsystem, an imaging member, and an inking subsystem. The electrophotographic subsystem comprises a photoreceptor, a charging subsystem, an exposure subsystem, and a development subsystem. In operation, the photoreceptor is charged areawise. An exposure pattern is formed by the exposure subsystem on the surface of the charged photoreceptor to thereby write a latent charge image onto the photoreceptor surface. The image is developed with an image definition material, such as a dampening fluid. The image definition material forms a positive pattern of the image to be printed. The image pattern is then transferred to the reimageable surface. The transferred pattern is then developed by selectively applying an ink over regions of image definition material. The inked image may be transferred to a substrate.

A copolymer includes (i) a plurality of ethylenic moieties A having a structure according to the formula:

##STR00001## wherein R.sup.2 and R.sup.3 independently represent hydrogen, a halogen, an optionally substituted linear, branched, or cyclic alk(en)yl group, or an optionally substituted aromatic or heteroaromatic; (ii) a plurality of acetal moieties B having a structure according to the formula:

##STR00002## wherein L.sup.1 represents a divalent linking group, x=0 or 1, and R.sup.1 represents an optionally substituted aromatic or heteroaromatic group including at least one hydroxyl group; and (iii) a plurality of acetal moieties C and/or moieties D which include a structural moiety including a chromophoric group having its main absorption in the infrared region.

A copolymer includes (i) a plurality of ethylenic moieties A having a structure according to the following formula:

##STR00001## wherein R2 and R3 independently represent hydrogen, a halogen or an optionally substituted linear, branched or cyclic alk(en)yl group, or an optionally substituted aromatic or heteroaromatic group, and (ii) a plurality of acetal moieties B having a structure according to the following formula:

##STR00002## wherein L represents a divalent linking group; x=0 or 1 and R1 represents an optionally substituted aromatic or heteroaromatic group including at least one hydroxyl group and optionally one or more additional substituent(s), and at least one electron withdrawing group in ortho or para position relative to the at least one hydroxyl group.

The main object of an embodiment of the present invention is to provide a printing plate with excellent transferability, printing durability, and resolution, a producing method for the printing plate, a producing method for a functional element utilizing the printing plate, and a printing apparatus. An embodiment of the present invention achieves the objective by providing a printing plate comprising: a substrate containing an elastic body swellable in a solvent, a hydrophobic solvent permeation preventing layer formed on the substrate in a pattern, and a hydrophilic portion that is formed on a surface of the substrate at an opening portion of the hydrophobic solvent permeation preventing layer and higher in hydrophilicity than the hydrophobic solvent permeation preventing layer.

An imaging member includes a surface layer comprising a fluoroelastomer-perfluoropolyether composite formed from a reaction mixture comprising a fluoroelastomer and a perfluoropolyether compound. Methods of manufacturing the imaging member and processes for variable lithographic printing using the imaging member are also disclosed.

An on-machine development type planographic printing plate precursor has a support and an image-recording layer on the support. The image-recording layer contains an initiator, an infrared absorber capable of donating electrons to the initiator, and a color-developing substance precursor. The image-recording layer can form an image by exposure to infrared laser, and in a case where the image-recording layer is exposed to an infrared laser with a wavelength of 830 nm at an energy density of 110 mJ/cm.sup.2, a brightness change L of the image-recording layer before and after the exposure is 3.0 or more. A method for preparing a planographic printing plate and a planographic printing method employ the on-machine development type planographic printing plate precursor.

A negative-working lithographic printing plate precursor includes a support and a coating containing a photopolymerizable layer including a polymerizable compound including: a free radical polymerizable group, and at least one moiety having a structure according to Formula (I): ##STR00001## wherein n represents an integer equal to 0 or 1; L.sup.1 represents a divalent linking group; and * denotes the linking positions to the rest of the structure, with the proviso that the carbonyl groups in Formula (I) are bonded to a carbon atom.

A copolymer includes (i) a plurality of ethylenic moieties A having a structure according to the following formula: ##STR00001##
wherein R.sup.2 and R.sup.3 independently represent hydrogen, a halogen, or an optionally substituted linear, branched, or cyclic alk(en)yl group, or an optionally substituted aromatic or heteroaromatic, and (ii) a plurality of acetal moieties B having a structure according to the following formula: ##STR00002##
wherein L represents a divalent linking group; x=0 or 1; and R.sup.1 represents an optionally substituted aromatic or heteroaromatic group including at least one hydroxyl group. Use of these polymers in the coating of lithographic printing plates provides a good abrasion resistance while the balance between the ink acceptance, arising from the ethylenic moieties, and the solubility in an alkaline developer, arising form the acetal moieties, can be controlled efficiently.