Provided are a lithographic printing plate precursor comprising: an image-recording layer on a support, in which the image-recording layer includes a dye compound having a decomposable group that is decomposed by an acid, heat, or both and a structure in which decomposition of the decomposable group opens a ring or desorbs a leaving group and an electron-donating polymerization initiator, a method for producing a lithographic printing plate in which the lithographic printing plate precursor is used, and a color-developing composition including a dye compound having a decomposable group that is decomposed by an acid, heat, or both and a structure in which decomposition of the decomposable group opens a ring or desorbs a leaving group and an electron-donating polymerization initiator.

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 where the image recording layer is provided is in a range of 0.3 m to 20 m; a method of producing a lithographic printing plate precursor; a lithographic printing plate precursor laminate formed of the lithographic printing plate precursor; a plate-making method for a lithographic printing plate; and a lithographic printing method.

Provided are a lithographic printing plate precursor having an image-recording layer on a hydrophilic support, in which the image-recording layer contains an infrared absorbing dye that decomposes by exposure to an infrared ray and a color developer that develops color due to the exposure to an infrared ray and a method for producing a lithographic printing plate in which the lithographic printing plate precursor is used.

Provided are a lithographic printing plate precursor having an image-recording layer on a hydrophilic support, in which the image-recording layer includes an organic polymer particle, and the organic polymer particle is a reaction product obtained by at least reacting an aromatic polyvalent isocyanate compound having a structure represented by Formula PO and water, a method for making a lithographic printing plate having excellent printing resistance in the case of using an ultraviolet-curable ink in printing, a new organic polymer particle, and a resin composition including the organic polymer particle.

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A flexo-plate maker uses two different curable liquids. After curing, the curable liquids result in different physical properties. Optionally, the system also uses two illumination subsystems preferably with a different resolution.

A method of imaging printing plates uses a single imaging device having at least one laser delivering, in an imagewise manner, pulsed electromagnetic energy of pulse duration not greater than 110.sup.6 seconds. Such an imaging method permits the imaging of a plurality of types of printing plates irrespective of any sensitised imaging chemistry contained in their coatings.

A color-forming composition is useful to provide a printout image in an imaged lithographic printing plate precursor. This color-forming composition includes (a) an acid generator; (b) a tetraaryl borate; (c) an acid-sensitive dye precursor; and (d) a compound having the following Structure (I):

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wherein n is 1, 2, 3, or 4; R independently represents a monovalent substituent or the atoms necessary to form a fused ring if n is at least 2, and at least one R substituent is an electron-withdrawing group. The color-forming composition is included within a negative-working radiation-sensitive imageable layer along with a free radically polymerizable component and a radiation absorber such as an infrared radiation absorber.

Provided are a lithographic printing plate precursor having an image-recording layer on a hydrophilic support, in which the image-recording layer includes a polymer particle including an addition polymerization-type resin having a hydrophilic structure and a crosslinking structure, a method for producing a lithographic printing plate in which the lithographic printing plate precursor is used, a polymer particle including an addition polymerization-type resin having a hydrophilic structure and a crosslinking structure, and a composition including the polymer particle.

Systems and processes for making a flexo plate, and plates made thereby. Non-printing indicia defined by areas of presence and absence of polymer in the plate floor are readable downstream of the washing or other non-cured-polymer-removal step but do not print in the printing step. The non-printing indicia may define a repeating pattern of alphanumeric characters, non-text graphics, or a combination thereof.

The imaging sensitivity of negative-working lithographic printing plate precursors is improved by removing ozone from the ambient air surrounding the precursors that can be stored near an imaging means such as a platesetter prior to use. Ozone can be removed using a suitable filter containing activated charcoal or other ozone decomposing means, through which ambient air is filtered before and during the imaging process.