Provided are a lithographic printing plate precursor including: a hydrophilized aluminum support, and a water-soluble or water-dispersible negative type image recording layer provided on the aluminum support, in which an arithmetic average height Sa of a surface of an outermost layer on a side opposite to a side where the image recording layer is provided is in a range of 0.3 m to 20 m; a method of producing the lithographic printing plate precursor; a lithographic printing plate precursor laminate formed of the lithographic printing plate precursor; and a lithographic printing method.

A lithographic printing plate precursor is disclosed including a support and a coating comprising (i) a photopolymerisable layer including a polymerisable compound and a photoinitiator, and a toplayer provided above the photopolymerisable layer: characterized in that the toplayer includes a halogenated polymer and a nitrite and/or nitrate salt.

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.

An infrared-sensitive color developing composition develops colors in a high density with an infrared exposure and does not significantly discolor when aged. A lithographic printing plate precursor which has extremely excellent plate-inspecting properties and favorable storage stability and is capable of maintaining favorable color-developing properties is provided, as is a plate making method for a lithographic printing plate in which the lithographic printing plate precursor is used. A new compound that can be preferably used as an infrared-sensitive color developer is also provided. An infrared-sensitive color developing composition of the invention includes a compound represented by Formula (1) (Component A). In addition, the compound in the present invention is represented by Formula (1). ##STR00001##

This application relates to lithographic printing plates, methods of making said plates, and precursor plates for use in said methods.

Provided is a printing plate precursor including: a support; a layer which contains a polymer on one side of the support; and a layer which contains a metal oxide obtained by hydrolyzing and polycondensing an organic metal compound or an inorganic metal compound and fine particles on the other side of the support, in which an average particle diameter of the fine particles is 0.3 m or greater and is greater than the thickness of the layer containing a metal oxide and fine particles, and in a case where the printing plate precursors are laminated, dislocation in stacking precursors, adhesion between precursors, and scratches can be all prevented even without using interleaving paper.

The invention is directed to a lithographic printing plate precursor including, in the following order: a support; an image-recording layer containing a radical polymerizable compound and a radical polymerization initiator; and a protective layer containing a star polymer, and the star polymer is preferably a polymer in which from 3 to 10 polymer chains are branched from a central skeleton.

An object of the present invention is to provide an on-press development-type planographic printing plate precursor which suppresses color-forming defect after a lapse of time and has excellent visibility. Another object of the present invention is to provide a manufacturing method of a planographic printing plate and a printing method. The planographic printing plate precursor of the present invention is an on-press development-type planographic printing plate precursor including a support and an image-recording layer, in which the support has an aluminum alloy plate and an anodic oxide film disposed on the aluminum alloy plate, a density of intermetallic compounds having a major axis of 2.0 m or more on a surface of the support on a side opposite to the image-recording layer is 1,000 pieces/mm.sup.2 or less, the image-recording layer contains an infrared absorber and an acid color-forming agent, and a color-forming factor of the acid color-forming agent, which is determined by a predetermined measuring method, is 20,000 or more.