Radiation imagery chemistry: process – composition – or product th – Microcapsule – process – composition – or product
Reexamination Certificate
2000-04-18
2002-11-12
Baxter, Janet (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Microcapsule, process, composition, or product
C430S046400, C430S084000, C430S133000, C430S270100
Reexamination Certificate
active
06479207
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to an image forming material by imagewise exposing the element to infrared laser and converting the laser light to heat and a production method of the element, particularly relates to improvement of the light-heat conversion material.
BACKGROUND OF THE INVENTION
Recently, a technology (CTP) has been noted accompanied with progress of semiconductor laser and digital image processing technology using a computer, in which a PS plate is by directly imagewise exposing to a light by scanning with a light beam emitted by a semiconductor laser according to image data prepared by a computer for making a planographic printing plate. Therefore, a CTP is required having a printing suitability equal to that of a PS plate which is low in price and easy for handling. Various CTP systems utilizing infrared laser recording are proposed recently. Among them, a CTP so called dry CTP is noted, which does not require any specific developing process. The dry CTP includes a CTP to be developed on printing machine. Examples of such the technology include the followings.
Japanese Patent Publication Open to Public Inspection (JP O.P.I.) No. 8-507727 discloses an image forming element and a method. The element is a heat mode recording element which comprises a substrate having on it an ink acceptable surface, anda recording layer containing a light-heat conversion material and a layer having a hardened hydrophilic surface and containing a light-heat conversion material each coated on the substrate. The recording layer and the layer provided at the upper side of the recording layer are removed by ablation by a laser to form an image.
JP O.P.I. No. 6-186750 discloses a method and an apparatus to form an image, in which a plate having a first layer and a second layer different from each other in the affinity to an ink or an ink adhesion preventing liquid is scanned by an infrared laser to ablate one or more of the layers for forming an image.
JP O.P.I. No. 6-199064 discloses a laser recording planographic printing plate element for forming an image by ablation which comprises a substrate having thereon an upper first layer absorbing infrared rays and a lower second layer, or an upper first layer and a lower second layer absorbing infrared rays, and the first and second layers are different from each other in the affinity to ink or ink adhesion preventing liquid.
JP O.P.I. No. 7-314934 discloses a laser recording printing element and a method for forming an image by ablation. The element comprises a not ablative most upper layer, an ablative thin metal layer of titanium or a titanium alloy and a substrate, and the most upper layer and the substrate are different from each other in the affinity to ink or ink adhesion preventing liquid.
JP O.P.I. No. 10-58636 discloses a planographic printing plate comprising a substrate having thereon a laser reactive hydrophilic swellable layer (preferably containing a colored pigment or black dye). The hydrophilic swellable layer is ablated by exposing to a laser light beam to form a inky image.
In the heat mode laser recording printing plate element including the above-mentioned ones, the unevenness of the dispersion of the light-heat conversion material in the layer some times causes a problem that causes lowering in the sensitivity or resolution ability. Particularly, a metal oxide having an electric conductivity such as titanium black is difficultly dispersed in the coating liquid and easily make an aggregate so as to tend to cause lowering in the sensitivity and resolution ability since such the substance.
It is usual in the above-mentioned methods that any layer provided on the substrate has a light-heat conversion ability and the layer having the light-heat conversion ability is formed by coating a layer in which a light-heat conversion material is mixed and/or dispersed. The amount and the dispersion degree of the light-heat conversion material in the layer are closely related to the sensitivity to the laser light. When an infrared absorbing dye soluble in the solvent of the coating liquid for forming the layer is used as the light-heat conversion material, the cost of the plate is raised since the infrared absorbing dye is very expensive although the dispersibility is good and the sensitivity is high concerning the amount thereof. Moreover, a wetting solution is difficultly applied to the printing plate since the water resistivity of the coated layer is lowered, when a water-soluble dye is added into an aqueous layer.
When a light-heat conversion material is in a form of solid fine particle, a relatively large adding amount thereof is required if the dispersion degree of it is low. Such the matter causes problems such that the cost is raised, the Resolution ability is lowered even though a sufficient sensitivity can be obtained, and the physical property of the coated layer is lowered and sufficient strength for printing plate cannot be obtained.
An electroconductive metal oxide is preferred as the material for using the printing plate according to the various properties thereof among the solid fine particle light-heat conversion substances. However, the material such as titanium black is very difficultly dispersed in the coating liquid and a method for improving the dispersing degree is demanded.
JP O.P.I. No. 10-244773 proposes as one of such the countermeasure that particles having a diameter of from 0.1 &mgr;m to 2.0 &mgr;m account for 50% or more of the total amount of titanium black dispersed in the layer having the light-heat conversion ability. The actual method for attaining to such the dispersed condition is a usual way by which the particles are kneaded by three rollers or a kneader before the dispersion using beads. Therefore, raising in cost in the dispersion process cannot be exempted. Moreover, the conversion efficiency of light to heat is not sufficiently improved since the titanium black having a primary particle diameter of several decades nanometer is used in a particle size of from 0.1 to 2.0 &mgr;m.
The printing plate element for forming an image without ablation of the layer having the light-heat conversion ability has a large advantage that the laser head is not contaminated even when any protection is not provided to the exposing device since the ablated substance is not scattered at the time of exposing to laser light. However, the layer near the light-heat conversion particle is locally ablated since heat is only locally generated and the temperature of the whole layer is not be raised when the light-heat conversion material having a diameter of about 2 &mgr;m is contained in the light-heat conversion layer of the printing plate having such the constitution. Accordingly, the sensitivity of the layer is lowered.
Furthermore, the surface of the printing plate formed by the coated layer tends to be insufficient in the strength, and a damage by scratching is frequently raised as a problem since it causes a contamination of the printed image.
Furthermore, the image forming element in which imagewise irradiated infrared laser light is converted to heat by a light-heat conversion material to form an image, other than the foregoing planographic plate element, has had problems of lowering in the sensitivity and the resolution ability and occurring of ablation caused by local heat generation. Such the problems caused by uneveness of dispersion of the light-heat conversion material.
SUMMARY OF THE INVENTION
The object of the invention is to provide an image forming material such as a printing plate, laser thermal transfer recording material, capable of being recorded by a heat mode recording, which has a high sensitivity, high resolution ability and a high abrasion resistivity, and contamination caused by scratch is difficultly formed, and producing method thereof.
The constituent of the invention for attaining the above-mentioned object is followings.
1. An image forming material comprising a support, and a component layer, wherein the component layer contains a particle comprising a core covered with a
Baxter Janet
Frishauf Holtz Goodman & Chick P.C.
Gilliam Barbara
Konica Corporation
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