Patent ID: 6911300

Claim:
A photogravure plate making method, wherein (A) an upper end of a vertical coating pipe is placed near below one end of a photogravure plated roll chucked at both ends in a horizontal state and rotated, (B) said coating pipe is moved up to the other end of the photogravure plated roll, (C) a positive-type photosensitive agent composed of alkaline soluble positive-type photosensitive composition having an infrared wavelength range laser sensitivity with a developing latitude where image line part exposed by the alkaline developing liquid is washed away and a non-image line part not exposed is not washed away under non-heating after forming a coated film at one end is slightly bulged out and overflown of an upper end of said coating pipe, (D) the photogravure plated roll is coated through a spiral coating system, (E) upon completion of coating operation, the rotation of the photogravure plated roll is continued to form a natural dried coating film, then the photogravure plated roll is rotated at a speed which (1) disperse the residual solvent in the coated film into the air, (2) reduce a concentration of the residual solvent and (3) form a photosensitive film, and subsequently, (F) a positive image is exposed with an infrared wavelength range laser against the photosensitive film, (G) either main chain or side chain of the molecules of photosensitive film forming resin at said exposed part is cut to cause it to become a lower molecule having more increased alkaline solubility, (H) a latent image having a photosensitive layer ablation is formed, then (I) alkaline development is carried out, and (J) the photosensitive film forming resin at the exposed part is washed away to leave only the resist at the non-image line.