A polymerizable composition is provided, including an infrared absorber, a polymerization initiator, a polymerizable compound, and a polymer binder, wherein the polymer binder is a particulate random copolymer, and the polymer binder has structural units derived from a polymerizable polyalkylene oxide-based monomer and a polymerizable nitrogen-free non-polyalkylene oxide-based monomer. The polymerizable composition may be used in the production of imageable elements or printing plates.

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.

A method of lithographic plate making is disclosed wherein a plate precursor is exposed to laser radiation in the wavelength range from 350 to 450 nm, said plate precursor comprising a hydrophilic support and a photopolymerizable or photocrosslinkable image recording layer, and then processed on-press by supplying fountain and ink. The exposure produces a visible image having a 1976 CIELAB color distance AF between exposed and non-exposed areas of at least 2.5.

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 or alkoxy groups each having 2 to 9 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 to 4; 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 to 4; and X.sub.1, X.sub.2 and X.sub.3 are the same or different anions.

Provided is a planographic printing plate precursor including: a support; and an image recording layer formed on the support, in which a region on the plate surface on the image recording layer side from an end portion of the planographic printing plate precursor to a portion inside the end portion by 5 mm contains a polymer containing a functional group represented by the following Formula (A), and the content of the polymer per unit area in the region is greater than the content of the polymer per unit area in a region other than the above-described region by an amount of 10 mg/m.sup.2 or greater.

—Si(X).sub.m(R.sup.3).sub.n  (A)

Provided is a lithographic printing plate precursor having a support and an image-recording layer on the support, in which the image-recording layer has an infrared absorber, a polymerization initiator, a polymerizable compound 1, a polymerizable compound 2, and a polymerizable compound 3, in which a molecular weight of the polymerizable compound 1 is less than 1,000, a weight-average molecular weight of the polymerizable compound 2 is 1,000 or more and 3,000 or less, and a weight-average molecular weight of the polymerizable compound 3 is more than 3,000 and 15,000 or less.

A planographic printing plate precursor includes: a support; and an image recording layer which includes a radical initiator, a radical polymerizable component, and a radiation absorption compound, and in which the image recording layer shows two or more peaks of a radical generation amount in a radical generation amount-versus-time curve after exposure to image forming radiation, in which the radical initiator includes an electron-donating radical initiator and an electron-accepting radical initiator, and the radiation absorption compound comprises a compound represented by the following Formula 1. ##STR00001##

Lithographic printing plate precursors have an aluminum-containing substrate prepared using two anodizing processes to provide an inner aluminum oxide layer of average dry thickness of 300-3,000 nm and a multiplicity of inner micropores of average inner micropore diameter of ≤100 nm. An outer aluminum oxide layer is provided with a multiplicity of outer micropores of average outer micropore diameter of 15-30 nm and a dry thickness of 30-650 nm. A hydrophilic layer is disposed on the outer aluminum oxide layer at 0.0002-0.1 g/m.sup.2 and has a (1) compound having an ethylenically unsaturated polymerizable groups; a —OM group connected directly to a phosphorus atom, wherein M represents hydrogen, sodium, potassium, or aluminum; and (2) one or more hydrophilic polymers having (a) recurring units comprising an amide group, and (b) recurring units having an —OM′ group that is directly connected to a phosphorus atom, wherein M′ represents hydrogen, sodium, potassium, or aluminum.

Provided is a lithographic printing plate precursor having an aluminum support and an image-recording layer formed on the aluminum support, in which the image-recording layer contains resin particles A that have an ethylenically unsaturated group and a compound B that has an ethylenically unsaturated group other than the resin particles A and has an ethylenically unsaturated bond valence of 1.5 mmol/g or more. Also provided are a method for preparing lithographic printing plate or a lithographic printing method using the lithographic printing plate precursor.

Provided is an on-press development type lithographic printing plate precursor including an aluminum support and an image-recording layer on the aluminum support, in which the image-recording layer contains an infrared absorber, a polymerization initiator, a polymerizable compound, and an addition polymerization-type resin having a hydrophilic structure, a water contact angle on a surface of the aluminum support on a side of the image-recording layer that is determined by an airborne water droplet method is 110° or less, and the polymerizable compound includes a polymerizable compound having 7 or more functional groups. Also provided are a method for preparing a lithographic printing plate and a lithographic printing method using the lithographic printing plate precursor.