Disclosed is a heat-sensitive processless planographic printing plate material containing a thermosensitive protection layer. The planographic printing plate material sequentially comprises a supporting body, a hydrophilic layer, a heat-sensitive layer and a thermosensitive protection layer from the bottom up. The thermosensitive protection layer therein can not only isolate oxygen and protect the heat-sensitive layer from oxygen inhibition, but can also sense heat and allow a polymerization reaction to take place. Thus the binding force between same and the next layer is improved, so that the precision of printing plate images is high, the development performance is good, and the pressrun is high.

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 negative-working infrared radiation-sensitive lithographic printing plate precursor can be imaged and developed on-press to provide a lithographic printing plate. Such precursor has an initiator composition that contains compound A of Structure (I) and one or more compounds collectively as compound B of Structure (II) or Structure (III): ##STR00001##
wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are independently alkyl groups each having 3 to 6 carbon atoms; at least one of R.sub.3 and R.sub.4 is different from R.sub.1 or R.sub.2; the difference of total number of carbon atoms in R.sub.1 and R.sub.2 and the total number of carbon atoms in R.sub.3 and R.sub.4 is 0, 1, or 2; the difference of total number of carbon atoms in R.sub.1 and R.sub.2 and the total number of carbon atoms in R.sub.5 and R.sub.6 is 0, 1, or 2; and X.sub.1, X.sub.2 and X.sub.3 are the same or different anions.

IR-sensitive lithographic printing plate precursors provide a high contrast and stable printout image using an IR radiation-sensitive composition. This composition includes: a free radically polymerizable component, an IR absorber, an initiator composition, color-forming compound(s) such as a specific leuco dye, and compound(s) represented by the following Structure (P):

##STR00001##

wherein X is O, S, NH, or CH.sub.2, Y is >N or >CH, R.sup.1 is hydrogen or an alkyl, R.sup.2 and R.sup.3 are independently halo, thioalkyl, thiophenyl, alkoxy, phenoxy, alkyl, phenyl, thioacetyl, or acetyl, and m and n are independently 0 or an integer of 1 to 4. The printout image exhibits a color contrast between the exposed and non-exposed regions of a E greater than 8. A E of at least 5 is maintained between the exposed and the non-exposed regions with exposure to white light for at least one hour. These precursors, when IR-exposed, can be developed on-press.

Lithographic printing plate precursors are prepared with a unique substrate using two separate anodizing processes to provide an inner aluminum oxide layer of average dry thickness (T.sub.i) of 650-3,000 nm and a multiplicity of inner micropores of average inner micropore diameter (D.sub.i) of 15 nm. An outer aluminum oxide layer comprises a multiplicity of outer micropores of average outer micropore diameter (D.sub.o) of 15-30 nm; dry thickness (T.sub.o) of 130-650 nm; and a micropore density (C.sub.o) of 500-3,000 micropores/m.sup.2. The ratio of D.sub.o to D.sub.i is greater than 1.1:1. A hydrophilic layer disposed on the outer aluminum oxide layer has a copolymer composed of (a) recurring units and (b) recurring units, wherein the (a) recurring units have an amide group, and the (b) recurring units have at least a phosphonic acid, a phosphoric acid, a salt of a phosphonic acid, or a salt of a phosphoric acid group.

A method for making a lithographic printing plate is disclosed including the steps of (i) image-wise exposing a printing plate precursor to heat and/or IR radiation; said precursor including a support and a coating comprising a polymerisable compound, an infrared absorbing compound, a borate compound and a photoinitiator including a trihaloalkyl group; (ii) developing the exposed precursor by treating the coating of the precursor with a gum solution thereby removing the coating from the support at the non-image areas; 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 precursor.

A lithographic printing plate precursor is disclosed including a coating comprising a polymerisable compound, an infrared absorbing dye, a photoinitiator including a trihaloalkyl group and a borate compound.

Provided are a planographic printing plate precursor and a method of producing a planographic printing plate precursor, in which an image forming region during printing on newspaper page is ensured and edge stains are eliminated. Provided are a planographic printing plate precursor (10b) including an aluminum support (12) which has an anodized film (14), and an image recording layer (16) on the aluminum support (12), in which an end portion of the planographic printing plate precursor (10b) has a sagging shape having a sagging amount (X) of 25 m to 150 m and a sagging width (Y) of 70 m to 300 m, the image recording layer (16) contains an infrared absorbing agent, and a part or an entire side surface of two sides of the aluminum support (12), the two sides having the sagging shape and opposing each other contains an ink repellent agent (44); and a method of producing the planographic printing plate precursor (10b).

Provided are a planographic printing plate precursor including a support and an image recording layer formed on the support, in which the image recording layer contains a polymer A which includes a constitutional unit A1 having an ethylenically unsaturated group, a weight-average molecular weight of the polymer A is in a range of 2,500 to 35,000, and a content of the constitutional unit A1 in the polymer A is 15 mol % or more, and a method of producing a planographic printing plate using the planographic printing plate precursor.

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.