| abstract |
Exposure is possible by scanning with a laser beam, high sensitivity and good storability. Also, during development, the exposed portion of a photosensitive layer is excellent in solubility, so that a clear image can be developed and printing durability is improved. Provided are a positive photosensitive lithographic printing plate having excellent chemical resistance, a method for producing the same, and a positive image forming method using the same. A photosensitive layer containing a photothermal conversion material having an absorption region in a wavelength range of 600 nm to 1300 nm and an alkali-soluble resin and not containing an o-quinonediazide compound, the photosensitive layer having a surface thereof By diffusing a compound having a polar group from (1) in an unexposed state, (1) the average dissolution rate of the surface portion from 100% to 90% of the film thickness in an alkaline developer is expressed as V 1 , A positive photosensitive lithographic plate having a gradient of solubility (V 2 / V 1 ) in the thickness direction of the photosensitive layer of 2 or more, where V 2 is an average dissolution rate inside the film thickness of 90% to 0%. Print version. [Selection figure] None |