Radiation imagery chemistry: process – composition – or product th – Microcapsule – process – composition – or product
Reexamination Certificate
2001-01-22
2004-04-27
Chu, John S. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Microcapsule, process, composition, or product
C430S175000, C430S270100, C430S302000
Reexamination Certificate
active
06727031
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an infrared-sensitive image forming material which can be used for planographic printing plates, color proofs, photoresists or color filters and, particularly, to a negative or positive type infrared-sensitive image forming material which can be used as a plate material for planography, which enables so-called direct plate formation in which a plate can be formed directly by scanning an infrared laser based on digital signals from a computer or the like.
2. Description of the Related Art
The development of lasers in recent years has been remarkable. In particular, high-output, compact solid-state lasers and semiconductor lasers that emit infrared light having wavelengths ranging from 760 nm to 1200 nm (occasionally referred to as an “infrared laser” hereinafter) have become readily available. These infrared lasers are extremely useful as a recording light source at the time a printing plate is formed directly on the basis of digital data from a computer or the like. Accordingly, demand for photosensitive resin compositions whose sensitivity to such an infrared recording light source is high has been rising in recent years. Namely, there is an increasing demand for photosensitive resin compositions in which a photochemical reaction or the like occurs upon being irradiated with an infrared beam to thereby greatly change the solubility of the photosensitive resin composition in a developing solution.
Examples of such photosensitive resin compositions that are recordable by an infrared laser include the recording material formed of an onium salt, a phenol resin and a spectral sensitizer disclosed in U.S. Pat. No. 4,708,925. This photosensitive resin composition is a positive-type, photosensitive resin composition that utilizes an effect, generated by the onium salt and the phenol resin, that deters dissolution in a developing solution.
On the other hand, examples of negative-type, photosensitive resin compositions include the recording material disclosed in Japanese Patent Application Laid-Open (JP-A) No. 8-276558. This recording material is formed of a substance that absorbs light to generate heat, an alkali-soluble resin, and a specific phenol derivative having in the molecules thereof 4 to 8 benzene nuclei.
Although these recording materials convert laser light into heat and use this heat as recording energy, sensitivity to laser exposure in each case has been insufficient.
Namely, there have been problems in that, with regard to positive-type image forming materials, inhibition to developability in an alkali developing solution cannot be sufficiently removed by heat and, with regard to negative-type image forming materials, even though acids or radicals are generated by heat, generative effectiveness is low because the heat ends up being diffused. Measures have been investigated that increase a compounding amount of infrared absorbents in order to improve the effectiveness of light/heat conversion. However, there has been the apprehension that when the compounding amount of infrared absorbents is increased, light permeability of the recording layer will deteriorate, it will become difficult for the infrared laser to penetrate the deep portion of the recording layer, and image discrimination will deteriorate. For this reason, not only is there the problem of sensitivity, but there is also the problem that it is difficult for ON-OFF in end portions of an obtained image to achieve clarity. Therefore, improvements in sensitivity and in the discrimination of an image to be formed have been desired.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an infrared-sensitive image forming material with which a plate can be formed directly from digital data of a computer or the like using a solid laser or a semiconductor laser that emits an infrared beam, whose sensitivity to an infrared laser is high, and with which discrimination of a formed image is excellent.
The above object of the present invention can be achieved by an infrared-sensitive image forming material comprising a support and a recording layer disposed thereon whose solubility in an aqueous alkaline solution is altered by irradiation with an infrared laser, wherein the recording layer has a binder phase formed of a polymer compound, a dispersion phase that is dispersed in the binder phase, and an infrared absorbent present in either one of the binder phase and the dispersion phase, and within a total incorporated amount of the infrared absorbent in the recording layer, a mass present in the dispersion binder is greater than a mass present in the binder phase.
In one aspect of the infrared-sensitive image forming material, the mass of the infrared absorbent present in the dispersion phase is no less than 70% by mass of the total incorporated amount of the infrared absorbent in the recording layer.
In another aspect of the infrared-sensitive image forming material, the dispersion phase comprises a polymer compound that is incompatible with the polymer compound forming the binder phase.
In another aspect of the infrared-sensitive image forming material, the dispersion phase may be one of a latex and a microcapsule.
In another aspect of the infrared-sensitive image forming material, the dispersion phase has a configuration in which a maximum length is 0.1 &mgr;m to 0.8 &mgr;m and an average length is 0.05 &mgr;m to 0.6 &mgr;m.
In another aspect of the infrared-sensitive image forming material, at least one of the binder phase and the dispersion phase comprises a polymer compound that is insoluble in water and soluble in an aqueous alkaline solution, the recording layer has a compound in which one of an acid and a radical is generated by irradiation with an infrared laser, and at least one of the binder phase and the dispersion phase comprises a polymer compound whose solubility in an aqueous alkaline solution is changed by an action of one of the acid and the radical.
In another aspect of the infrared-sensitive image forming material, at least one of the binder phase and the dispersion phase comprises a polymer compound that is insoluble in water and soluble in an aqueous alkaline solution, the recording layer has a compound in which one of an acid and a radical is generated by irradiation with an infrared laser, and at least one of the binder phase and the dispersion phase comprises a polymer compound in which one of polymerization and a cross-linking reaction occurs by an action of one of the acid and the radical to lower solubility in an aqueous alkaline solution.
In another aspect of the infrared-sensitive image forming material, at least one of the binder phase and the dispersion phase comprises a polymer compound that is insoluble in water and soluble in an aqueous alkaline solution, and the infrared absorber comprises a polymer compound that is an onium salt in which a solubility of at least one of the binder phase and the dispersion phase in an aqueous alkaline solution is raised by irradiation with a infrared laser.
In another aspect of the infrared-sensitive image forming material, the binder phase comprises a polymer compound that is insoluble in water and soluble in an aqueous alkaline solution, and the dispersion phase has a composition whose solubility in an aqueous alkaline solution is changed by irradiation with an infrared laser.
In another aspect of the infrared-sensitive image forming material, the recording layer has a compound that is cross-linked by an action of one of an acid and a radical, and with which a negative-type image can be formed by the recording layer being hardened by irradiation with an infrared laser.
In another aspect of the infrared-sensitive image forming material, the binder phase comprises a polymer compound that may be selected from a urethane polymer compound, an acryl polymer compound, a styrene polymer compound, a novolac resin, a diazo resin, an amide polymer compound and a polyether compound.
In another aspect of the infrared-sensitive image forming material, the dispe
Kunita Kazuto
Shimada Kazuto
Burns Doane , Swecker, Mathis LLP
Chu John S.
Fuji Photo Film Co. , Ltd.
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