Negative working diazo light-sensitive composition with oxonol dye and lithographic printing plate using the same
AssigneeFuji Photo Film Co., Ltd.
InventorsHiroshi Takahashi, Akira Nishioka, Fumihiro Tokunaga, Yoshimasa Aotani, Koichiro Aono
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Abstract
A negative working light-sensitive composition and a lithographic printing plate using the composition are described. The printing plate is comprised of a hydrophilic support and a thin layer of a negative working light-sensitive composition on the support. The light-sensitive composition contains a light-sensitive diazo compound and a compound capable of increasing absorption over the light-sensitive wavelength region of the composition with increasing exposure time.
Claims18
A negative working light-sensitive composition comprising an admixture of (a) a light-sensitive diazo compound which contains at least two diazo groups and produces an acidic compound by photo-decomposition, and present in an amount sufficient to form an image after actinic exposure and development and (b) a compound capable of increasing absorption of at least a part of light ranging in the light-sensitive wavelength region of the composition with increasing exposure time, and present in an amount sufficient for increasing said absorption with increasing exposure time, said compound capable of increasing absorption being presented by the following general formula (I) ##STR12## wherein R represents an alkyl group or an alkoxycarbonyl group and Q represents a hydrogen atom or an aryl group or a substituted aryl group, and wherein the light-sensitive wavelength region of the composition is within the wavelength region 350 to 450 nm and compound (b) is one such that it is capable of increasing absorption for the light of the wavelength range from 350 to 450 nm.
A negative working light-sensitive lithographic printing plate, comprising:
- a hydrophilic support having coated thereon:
- a negative working light-sensitive layer comprising
- a negative working light-sensitive composition comprising:
- (a) a light-sensitive diazo compound which contains at least two diazo groups and produces an acidic compound by photodecomposition and present in an amount sufficient to form an image after active exposure and development;
- and
- (b) a compound capable of increasing absorption of at least part of a light ranging in the light-sensitive wavelength region of the composition with increasing exposure time, and present in an amount sufficient for increasing said absorption with increasing exposure time, said compound capable of increasing absorption being represented by the following general formula (I) ##STR13## wherein R represents an alkyl group or an alkoxycarbonyl group and Q represents a hydrogen atom or an aryl group or a substituted aryl group, and wherein the light-sensitive wavelength region of the composition is within the wavelength region 350 to 450 nm and compound (b) is one such that it is capable of increasing absorption for the light of the wavelength range from 350 to 450 nm.
Dependencies are inferred from the claim text.