Provided are a lithographic printing plate precursor having an image-recording layer on an aluminum support, in which the image-recording layer contains a polymerization initiator, an infrared absorber, a polymer particle, and a polymerizable compound, and the polymerizable compound has a) a molecular weight of 1,500 to 3,000, b) a double bond equivalent of 200 or less, and c) a CLog P of 9 or less and a method for producing a lithographic printing plate in which the lithographic printing plate precursor is used.

A system for preparing a photopolymer printing plate includes an imager, a plate unloader configured to automatically unload the plate from the imager and deliver the plate to an exposure unit comprising a plurality of UV LEDs, and a controller configured to operate the imager, the plate unloader, and the exposure unit. The imager has a rotatable drum configured to rotate while laser beams ablate portions of an ablatable layer of the printing plate in accordance with imaging data. The UV LEDs include a back array and a front array configured to expose the front of the UV-curable plate, at least one of which is configured to emit UV radiation toward the plate during relative motion between the plate and the array.

Provided is an on-press development type lithographic printing plate precursor having a support and an image-recording layer on the support, in which the image-recording layer contains a compound A that has a partial structure satisfying Δd≥15.5 wherein δd is a value of a dispersion element in the Hansen solubility parameters, and a content of the partial structure satisfying Δd≥15.5 in the compound A is 50% by mass or more with respect to a total mass of the compound. Also provided is a method of 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 having a support and an image-recording layer on the support, in which the image-recording layer contains an infrared absorber, a polymerization initiator, a polymerizable compound, and a color-developing substance precursor, and in a case where the image-recording layer is exposed to an infrared laser having a wavelength of 830 nm at an energy density of 110 mJ/cm.sup.2, a loss of ethylenically unsaturated bonds in an exposed area in the image-recording layer is 10% to 40% of ethylenically unsaturated bonds in a non-exposed area in the image-recording layer. Also provided is a method for preparing a lithographic printing plate or a lithographic printing method using the on-press development type lithographic printing plate precursor.

Lithographic printing plate precursors are prepared with a unique aluminum-containing substrate prepared using two separate anodizing processes to provide an inner aluminum oxide layer of average dry thickness (T.sub.i) of 300-3,000 nm and a multiplicity of inner micropores of average inner micropore diameter (D.sub.i) of ≤100 nm. An outer aluminum oxide layer is also provided to have a multiplicity of outer micropores of average outer micropore diameter (D.sub.o) of 15-30 nm and a dry thickness (T.sub.o) of 30-650 nm. A hydrophilic layer disposed on the outer aluminum oxide layer at 0.0002-0.1 g/m.sup.2 has at least a hydrophilic copolymer composed of (a) recurring units having an amide group and (b) recurring units comprising an —OM group directly connected to a phosphorus atom, wherein M represents a hydrogen, sodium, potassium, or aluminum atom.

A lithographic printing plate precursor has an infrared radiation-sensitive image-recording layer containing an IR absorber, and an ozone-blocking material of 1500 or less molecular weight and has structure (I), (II), or (III): ##STR00001##
wherein R is a hydrocarbon having 14-30 carbon atoms; m is 1 or 2; n is 1-6; the sum of m and n is >2 and <8; and A is a multivalent organic moiety free of R and OH groups and has a valence m+n; ##STR00002##
wherein R.sub.1 and R.sub.2 are alkyl groups of 14-22 carbon atoms, and o is 1-3;
R.sub.3C(═O)NR.sub.4R.sub.5   (III)
wherein R.sub.3 is an alkenyl with a C═C bond within a carbon-carbon chain of 16-30 carbons, and R.sub.4 and R.sub.5 are hydrogen or unsubstituted alkyls of 1-4 carbon atoms. Such ozone-blocking materials can be used to protect infrared radiation-sensitive dyes that may be degraded by ozone and thus improve imaging sensitivity.

Provided are a lithographic printing plate precursor including a support, and an image recording layer on the support, in which the image recording layer contains an infrared absorbing agent, a polymerization initiator, and core-shell particles, a core portion of each core-shell particle contains a resin A containing a functional group A, and a shell portion of the core-shell particle contains a resin B containing a functional group B that is bondable to or interactable with the functional group A and a polymerizable group: a method of preparing a lithographic printing plate using the lithographic printing plate precursor; and a lithographic printing method carried out using the lithographic printing plate precursor.

An object of the present invention is to provide an aqueous developer for a flexographic printing plate capable of maintaining excellent development scum dispersibility and improving brush contamination, and a manufacturing method of a flexographic printing plate using the same. The aqueous developer for a flexographic printing plate of the present invention is an aqueous developer for a flexographic printing plate, containing a surfactant represented by Formula (1), a surfactant represented by Formula (2), and water.

##STR00001##

A negative-working lithographic printing plate precursor includes a coating including vinylogous vitrimer particles. The vinylogous vitrimer particles include a resin having at least one moiety of formula (I), (II), and/or (III):

##STR00001##

Provided are a planographic printing plate precursor including a support and an image recording layer on the support, in which the image recording layer contains an organic particle containing a resin that has a constitutional unit A having a cation moiety and a constitutional unit B having an anion moiety; and a method of preparing a planographic printing plate using the planographic printing plate precursor.