Method for processing lithographic printing plate precursor, plate inspection method, image quality control method and dyeing aqueous solution used therein

Abstract

A method for processing a lithographic printing plate precursor, the method comprising: imagewise exposing a lithographic printing plate precursor, so as to form an exposed lithographic printing plate precursor; and then bringing the exposed lithographic printing plate precursor into contact with an aqueous solution containing a basic coloring matter, wherein the lithographic printing plate precursor comprises: a support; and an image recording layer containing a compound which interacts with a basic coloring matter and being removable by at least one of a printing ink and a fountain solution; methods for plate inspection and image quality control of a lithographic printing plate precursor, using the processing method; and a basic coloring matter-containing aqueous solution used for the processing.

Description

Claims

1. A method for processing a lithographic printing plate precursor, the method comprising: imagewise exposing a lithographic printing plate precursor, so as to form an exposed lithographic printing plate precursor; and thenbringing the exposed lithographic printing plate precursor into contact with an aqueous solution containing a basic coloring matter,wherein the lithographic printing plate precursor comprises:a support; andan image recording layer containing a compound which interacts with a basic coloring matter and being removable by at least one of a printing ink and a fountain solution.

2. The method for processing a lithographic printing plate precursor according to claim 1, wherein the compound which interacts with a basic coloring matter is an inorganic compound.

3. The method for processing a lithographic printing plate precursor according to claim 1, wherein the basic coloring matter has an absorption spectrum having λmax in a region of from 400 to 700 nm.

4. The method for processing a lithographic printing plate precursor according to claim 1, wherein the image recording layer has substantially no absorption spectrum having λmax in a region of from 400 to 700 nm.

5. The method for processing a lithographic printing plate precursor according to claim 1, wherein the image recording layer further comprises a radical polymerization initiator and a radical polymerizable compound.

6. The method for processing a lithographic printing plate precursor according to claim 2, wherein the inorganic compound is a layered compound having an aspect ratio of 20 or more.

7. A method for plate inspection of a lithographic printing plate precursor, the method comprising visualizing an image through following steps in numerical order comprising: (1) a step of imagewise exposing a lithographic printing plate precursor comprising: a support; and an image recording layer containing a compound which interacts with a basic coloring matter and being removable by at least one of a printing ink and a fountain solution, so as to form an exposed lithographic printing plate precursor;(2) a step of bringing the exposed lithographic printing plate precursor into contact with an aqueous solution containing a basic coloring matter to stain an exposed portion of the image recording layer; and(3) a step of drying the plate.

8. A method for image quality control of a lithographic printing plate precursor, the method comprising controlling image quality through following steps in numerical order comprising: (1) a step of imagewise exposing a lithographic printing plate precursor comprising: a support; and an image recording layer containing a compound which interacts with a basic coloring matter and being removable by at least one of a printing ink and a fountain solution, so as to form an exposed lithographic printing plate precursor;(2) a step of bringing the exposed lithographic printing plate precursor into contact with an aqueous solution containing a basic coloring matter to stain an exposed portion of the image recording layer;(3) a step of drying the plate, so as to form an image; and(4) a step of measuring a halftone dot area or density of the image by a halftone dot area meter or a densitometer.

9. An aqueous solution for dyeing a lithographic printing plate precursor, the aqueous solution comprising a basic coloring matter, wherein the aqueous solution is utilized for a method according to claim 1.