Lithographic printing plate precursor and plate making method of lithographic printing plate

摘要

By a lithographic printing plate precursor including a support having provided thereon an image-recording layer capable of forming an image by supplying at least any of printing ink and dampening water on a printing machine after image exposure to remove an unexposed area thereof, wherein the image-recording layer contains an infrared absorbing agent, a polymerization initiator, a polymerizable compound and a polysaccharide having a sulfonic acid group or a group made by a salt thereof and a plate making method of a lithographic printing plate using the same, a lithographic printing plate precursor which exhibits good development property while maintaining printing durability of a lithographic printing plate after development and a plate making method of a lithographic printing plate using the same can be provided.

主权项

1. A lithographic printing plate precursor comprising a support having provided thereon an image-recording layer capable of forming an image by supplying at least any of printing ink and dampening water on a printing machine after image exposure to remove an unexposed area thereof, wherein the image-recording layer contains an infrared absorbing agent, a polymerization initiator, a polymerizable compound and a polysaccharide having a sulfonic acid group or a group made by a salt thereof,
wherein the polysaccharide is cellulose having a sulfonic acid group or a group made by a salt thereof which has a repeating unit represented by the following formula (1):wherein R each independently represents a hydrogen atom, an alkyl group, a hydroxyalkyl group, a carboxyalkyl group or -L-SO3−X+, n represents an integer of 2 or more, L represents an ethylene group or a propylene group, and X+ represents a hydrogen ion, an alkali metal ion or an ammonium ion, provided that of three Rs in the repeating unit represented by formula (1), a number (substitution degree) of R represented by -L-SO3−X+ is from 0.3 to 2.5.