The present invention provides a silicone composition for use in a printing plate, the composition including at least: a SiH group-containing compound; a compound represented by the following general formula (I); a compound represented by the following general formula (II); and/or a compound represented by the following general formula (III); wherein Ds in the compound represented by the general formula (I), Gs in the compound represented by the general formula (II) and Js in the compound represented by the general formula (III) each represents an acetoxy group or a dialkyloximino group: A-Si-(D).sub.3 (I) (wherein in the general formula (I), A represents a non-hydrolyzable functional group capable of undergoing a hydrosilylation reaction with a SiH group); E-Si-(G).sub.3 (II) (wherein in the general formula (II), E represents a non-hydrolyzable functional group incapable of undergoing a hydrosilylation reaction with a SiH group); and Si-(J).sub.4 (III). An object of the present invention is to provide a silicone composition for use in a printing plate, for obtaining a planographic printing plate precursor or a planographic printing plate which includes a silicone rubber layer having an excellent adhesion to an underlying layer despite being a fast-curing silicone rubber layer, and which has an excellent ink repellency and scratch resistance.

A system for exposing a heat and/or light sensitive printing plate precursor including a coating on a support includes a platesetter including a laser head for generating a laser beam to create an image, and the platesetter further includes an electrostatic generator capable of electrostatically charging the surface of the coating.

Provided is a positive type lithographic printing plate precursor including at least: a support which has a hydrophilic surface or a hydrophilic layer; and an underlayer, an interlayer, and an upper layer on the support in this order, in which the underlayer contains a polymer compound 1 which has at least one structure selected from the group consisting of a urethane bond, an acetal structure, and a urea bond in a main chain, the interlayer contains a polymer compound 2 which has at least one structure selected from the group consisting of a sulfonamide group, an active imide group, and a urea bond in a side chain, the upper layer contains a polymer compound 3 which has a phenolic hydroxy group, and one or more layers among the underlayer, the interlayer, and the upper layer contain an infrared absorbent. Further, provided are a method of producing the positive type lithographic printing plate precursor and a method of preparing a lithographic printing plate using the positive type lithographic printing plate precursor.

A photosensitive resin composition contains a polymer compound having a constitutional unit represented by the following Formula A-1 as a constitutional unit A and at least one constitutional unit among constitutional units represented by the following Formulas B-1 to B-6 as a constitutional unit B in the main chain, and an infrared absorbing material. ##STR00001##

Provided are a positive type planographic printing plate precursor including: a support which has a hydrophilic surface; and an image recording layer on the support, the image recording layer containing: a polymer compound 1 having at least one bond selected from the group consisting of a urea bond, a urethane bond, and a carbonate bond in a main chain and containing a sulfonamide group in the main chain; a polymer compound 2-1 having at least one of a constitutional unit represented by Formula S-1 or a constitutional unit represented by Formula S-2 or a polymer compound 2-2 having a constitutional unit represented by Formula EV-1 and a constitutional unit represented by Formula EV-2; and an infrared absorbent, and a method of producing a planographic printing plate obtained by using the positive type planographic printing plate precursor.

##STR00001##

The present invention provides a silicone composition for use in a printing plate, the composition including at least: a SiH group-containing compound; a compound represented by the following general formula (I); a compound represented by the following general formula (II); and/or a compound represented by the following general formula (III); wherein Ds in the compound represented by the general formula (I), Gs in the compound represented by the general formula (II) and Js in the compound represented by the general formula (III) each represents an acetoxy group or a dialkyloximino group: A-Si-(D).sub.3 (I) (wherein in the general formula (I), A represents a non-hydrolyzable functional group capable of undergoing a hydrosilylation reaction with a SiH group); E-Si-(G).sub.3 (II) (wherein in the general formula (II), E represents a non-hydrolyzable functional group incapable of undergoing a hydrosilylation reaction with a SiH group); and Si-(J).sub.4 (III). An object of the present invention is to provide a silicone composition for use in a printing plate, for obtaining a planographic printing plate precursor or a planographic printing plate which includes a silicone rubber layer having an excellent adhesion to an underlying layer despite being a fast-curing silicone rubber layer, and which has an excellent ink repellency and scratch resistance.

Provided is a positive type photosensitive resin composition including: a polymer compound which contains, in a main chain thereof, a sulfonamide group and a structure represented by Formula A-1; and an infrared absorbent. In Formula A-1, X represents NR.sup.1, S, or O, R.sup.1 represents a hydrogen atom or an alkyl group, and each symbol * independently represents a bonding position with respect to another structure.

##STR00001##

The present invention provides a printing plate precursor including a layer which includes a polymer and is provided on a printing surface side of an aluminum support, and a layer which includes particles and is provided on a side opposite to the printing surface side, in which a modulus of elasticity of the particles is 0.1 GPa or more, and in a case where a Bekk smoothness of an outermost layer surface on the side opposite to the printing surface side is denoted by b second, a specific expression (1) is satisfied; a printing plate precursor laminate; a method for making a printing plate; and a printing method.

A planographic printing plate precursor having an image recording layer on a support, and an overcoat layer in this order, in which the overcoat layer includes particles, the overcoat layer is an outermost layer, and an occupation area ratio of the particles in a surface of the overcoat layer is 30% by area or more; and a method of producing a planographic printing plate obtained by using the planographic printing plate precursor.

Provided is a method of producing a planographic printing plate, including: subjecting a planographic printing plate precursor, which has a support and a positive-working image recording layer, to image-wise exposure; and developing it using an alkaline aqueous solution which contains a specific compound and has a pH of from 8.5 to 10.8, in this order. The recording layer has: a lower layer containing a water-insoluble and alkali-soluble resin and an infrared ray absorbing agent; and an upper layer containing a water-insoluble and alkali-soluble polyurethane resin and a polyorganosiloxane. The specific compound is a nonionic or anionic surfactant, or at least one compound represented by Formula (1) or (2), wherein R.sup.11, R.sup.12, and R.sup.13 each represent an alkyl group; R.sup.14 represents an alkylene group; and R.sup.15 represents a single bond or a divalent linking group containing a hetero atom; and R.sup.21, R.sup.22, and R.sup.23 each represent an alkyl group. ##STR00001##