A lithographic printing plate precursor is disclosed including a support and a coating comprising a sensitizer and an onium salt wherein the onium salt and the sensitizer are capable of inducing a print-out image upon UV light exposure.

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 is a manufacturing method of a flexographic printing plate, which achieves both a depth of a concave portion and reproducibility of independent dots by eliminating an insufficient depth of the concave portion and increasing a cured region around the independent dots. The manufacturing method of a flexographic printing plate includes an exposure step of irradiating, with an energy ray, a flexographic printing plate precursor which includes, in the following order, at least a support, a photosensitive layer, and a mask portion on which an image is formed, through the mask portion to expose the photosensitive layer, and a development step of removing a non-exposed portion of the photosensitive layer. The exposure step includes a step of radiating the energy ray in a state in which, from the photosensitive layer side, the mask portion and a film-like optical element are present in this order between an energy source and the photosensitive layer. The film-like optical element is an element which converges the incident energy ray to enhance directivity and emits the energy ray to the mask portion.

The platemaking apparatus according to the present invention forms a pattern on an ink film-forming press plate that has a surface layer containing a stimulus-responsive compound whose physical property can reversibly change in response to an external stimulus. The platemaking apparatus includes: a first stimulator that applies, to a surface of the press plate, a first stimulus that changes the physical property of the surface from a first physical property to a second physical property to form the pattern, on the basis of image data; a second stimulator that applies, to the surface of the press plate, a second stimulus that changes the physical property of the surface from the second physical property to the first physical property, to erase the pattern; and a cleaning unit that removes an ink remained on the surface of the press plate.

A lithographic printing plate precursor is disclosed including a support and a coating comprising (i) a photopolymerisable layer including a polymerisable compound and an optionally substituted trihaloalkyl sulfone photoinitiator, and (ii) a toplayer provided above the photopolymerisable layer; characterized in that the toplayer includes an infrared absorbing dye capable of forming a print-out image upon exposure to heat and/or IR radiation.

A halftone raster image, suitable for rendering a continuous-tone image, which comprises a plurality of dots, arranged according a screen ruling and screen angle. Said dots comprise (i) image pixels arranged as a first arc or as a plurality of arcs which together represent a first spiral, and (ii) non-image pixels arranged as a second arc or as a plurality of arcs which together represent a second spiral. Small displacements of the feed point of said dots away from the theoretical centre of a halftone dot, defined by said screen ruling and screen angle, enable a higher image quality and less patterns in said halftone raster image.

A halftone raster image, suitable for rendering a continuous-tone image, which comprises a plurality of dots, arranged according a screen ruling and screen angle. Said dots comprise (i) image pixels arranged as a first arc or as a plurality of arcs which together represent a first spiral, and (ii) non-image pixels arranged as a second arc or as a plurality of arcs which together represent a second spiral. Small displacements of the feed point of said dots away from the theoretical centre of a halftone dot, defined by said screen ruling and screen angle, enable a higher image quality and less patterns in said halftone raster image.

A lithographic printing plate precursor is disclosed including a support and a coating comprising (i) a photopolymerisable layer including a polymerisable compound, a borate compound and/or a photoinitiator and (ii) a toplayer provided above the photopolymerisable layer; characterized in that the toplayer has a thickness comprised between 0.1 g/m2 and 1.75 g/m2 and includes an infrared absorbing compound which includes a thermocleavable group which transforms into a group which is a stronger electron-donor upon exposure to heat and/or IR radiation, and is capable of forming a print-out image upon exposure to heat and/or IR radiation.

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.

Lithographic printing plates are provided by imagewise exposing negative-working lithographic printing plate precursors having one or more radiation-sensitive imageable layers, followed by contacting with a processing solution that contains up to 10 weight % of one or more compounds represented by Structure (I) shown as follows:

R.sup.1—C(═O)—N(R.sup.2)—R.sup.3   (I)

wherein R.sup.1, R.sup.2, and R.sup.3 independently represent hydrogen or a substituted or unsubstituted hydrocarbon group, or two or three of R.sup.1, R.sup.2, and R.sup.3 are combined to form one or more cyclic rings, and the total number of carbon atoms in the Structure (I) molecule is at least 7 and up to and including 33. Both negative-working and positive-working lithographic precursors can be imaged and processed using this processing solution using one or more successive applications of the same or different processing solution. The processing solution can be derived from a corresponding processing solution concentrate that can also be used for replenishment.