JPH058575A - Original plate for lithography - Google Patents

Abstract

PURPOSE:To obtain an original plate for lithography giving a lithographic plate directly enabling plate making without requiring wet type treatment such as development at the time of plate making and conducting distinct printing with high sensitivity and without dampening water through a simple system. CONSTITUTION:An original plate for lithography, which is manufactured by forming an image recording layer, in which particulates composed of an ink affinitive substance are dispersed in a binder consisting of an ink repellent substance, onto a substrate and exposes the ink affinitive substance at the section of image recording treatment to a surface by executing image recording treatment such as heat to the recording layer and can change the section into ink affinitive properties simply, is disclosed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a lithographic printing plate precursor,
In particular, lithographic printing that enables direct platemaking without the need for wet processing such as development, fixing, elution, and hydrophilization at the time of platemaking, and that can obtain high-definition printed images without dampening water during printing. It relates to the original edition.

[0002]

2. Description of the Related Art As a lithographic printing plate precursor, (1) a PS plate having a structure in which a surface of an aluminum plate is grained and a photosensitive layer is provided thereon, (2) oxidation is performed on a support such as paper. There are known electrophotographic plate-making master plates having a photoconductive layer made of zinc or the like, and (3) direct drawing masters having a structure in which the surface of a support is hydrophilized.

The surface of each of these original plates is hydrophilized, and plate making is carried out by adhering an ink-philic substance to the portion corresponding to the image. During printing, the hydrophilic non-image area repels the oil-based ink by applying dampening water, while the ink-philic image area does not carry dampening water, so the image is received by receiving the oil-based ink. Area and non-image area are separately obtained, which enables lithographic printing.

[0004]

However, since the difference between the so-called ink affinity and hydrophilicity between the image area and the non-image area is small, the influence of the amount of dampening water is large. If applied excessively, dampening water may remain in the ink-philic portion of the image area and repel the oil-based ink. On the other hand, when the amount of dampening water is small, there is a problem that the amount of water in the non-image area, which is the ink repellent portion, becomes small, the repelling of the oil-based ink becomes poor, and scumming occurs.

As a solution to these problems, waterless planographic printing plates which do not use fountain solution have been proposed (for example, JP-A-59-194895, JP-A-53-59508 and JP-A-53).
-69704, JP-A-59-211051). However, these lithographic original plates have problems that they require a plate-making machine dedicated to the original plate, a development step is required, or the printing clarity is poor.

Further, a so-called direct plate making technique is known in which a printing plate is directly finished from image information of a computer. For example, a type of transfer by electrophotography, a type of etching, a type of using a photosensitive mechanism of silver salt, a type of using a photopolymer, or the like. However, since these methods form an image by light and obtain a printing plate by a wet process such as development, fixing, elution, and hydrophilization, the plate making machine itself becomes large. It is not suitable for use in offices because it has problems such as soiling hands when handling chemicals such as liquids, and producing waste liquids. Moreover, the printing plate produced by these is suitable for ordinary printing using dampening water, but is not suitable for printing without dampening water.

The present invention has been made in view of these circumstances, and an object thereof is to use wet processing steps such as development, fixing, elution, and hydrophilization without using an ink ribbon or the like. It is an object of the present invention to provide a lithographic printing original plate which enables direct plate making without using a fountain solution and can give a lithographic printing plate with high definition without dampening water.

[0008]

The structure of a lithographic printing original plate according to the present invention which has been able to achieve the above object is a lithographic printing original plate comprising a substrate and an image recording layer provided on the substrate. The recording layer has a gist in that fine particles of an ink-philic substance are dispersed in a binder of an ink-repellent substance. In this case, if particles coated with an ink repellent substance that is the same as or different from the ink repellent substance that constitutes the binder are used as the particles of the ink repellent substance, the dispersion of the ink repellent substance in the ink repellent binder is used. It is possible to obtain a lithographic printing original plate which gives a printing plate having a higher sharpness and a higher definition.

[0009]

The lithographic printing plate precursor according to the present invention comprises, as an image recording layer formed on a substrate as described above, fine particles of an ink-philic substance dispersed in a binder of an ink-repellent substance. When this image recording layer is subjected to image processing by heat, discharge, etc., the binder is softened by the above processing in the image processing part and the ink-philic particles are raised on the surface, or further melted and softened and the surface of the ink layer is ink-philic. To form a conductive layer. On the other hand, such a change does not occur in the non-image area that is not affected by heat or the like, and the ink-repellent binder remains exposed on the surface, so that the surface portion retains the ink repellency.

As a result, in the image-processed lithographic printing plate, the ink-philic portion where the image portion is formed and the non-image ink-repellent portion are clearly demarcated on the surface, It enables high-quality image printing without dampening water.

At this time, if the surface of the fine particles made of the ink-affinitive substance is coated with an ink-repellent substance which is the same as or different from the binder, the dispersion of the fine particles in the binder is promoted and the image recording layer. It is preferable because not only the homogeneity can be further improved but also the background stain of the non-image processing portion can be more surely prevented. That is, the image-recording layer according to the invention of the present application is one in which the ink-philic fine particles are dispersed in the ink-repellent binder as described above, and in some cases, a part of the ink-philic fine particles is present on the surface of the non-image-processed portion. It may be exposed to become ink-philic locally and may cause ink stains on non-images. However, when ink-philic fine particles whose surface is coated with an ink-repellent substance as described above are used, the fine particles will be formed on the surface. Even when it is exposed, the ink repellency is ensured by the ink repellant coating layer, so that there is no fear of ink stains on the non-image area. When such coated fine particles are used, the ink repellent substance forming the coating layer is melted and removed by image processing such as heat treatment, so that the ink affinity of the image processing portion is not impaired.

The substrate used in the present invention includes a metal plate made of aluminum, mild steel, copper, stainless steel, zinc or the like, a metal sheet or metal film, a plastic plate made of polyester resin, polyethylene resin, polyvinyl chloride resin, polyamide resin or the like, Plastic sheet or film, paper, synthetic paper, paper or synthetic paper coated or laminated with the resin as described above, paper or plastic plate laminated or vapor-deposited with metal as described above,
A plastic sheet or a plastic film can be used.

In the present invention, the binder made of an ink repellent substance acts as a binder for stably dispersing fine particles made of an ink repellent substance in the binder, and imparts more reliable ink repellency to the non-image area. Any substance may be used as long as it has an action and has such an action effect, but it is particularly preferable in the sense of preventing scumming in the non-image area and enhancing the dispersion of the fine particles to improve the freshness. These include silicone-containing polymers such as silicone resin, silicone acrylic resin, silicone epoxy resin, silicone alkyd resin, silicone urethane resin, modified silicone resin, and silicone graft resin, tetrafluoroethylene resin, tetrafluoroethylene-perfluoroalkyl vinyl ether. Copolymer resin, tetrafluoroethylene Styrene copolymer resin, poly trifluorochloroethylene, polyvinylidene fluoride resins, fluorine-containing polymers such as polymers or copolymers of acrylic acid ester derivative or a methacrylic acid ester derivatives containing fluorine.

It should be noted that these ink-repellent substances must allow the ink-philic substance to be exposed to the surface layer in the image processing step such as heat, and for that purpose, thermal energy for image processing and the like. It is good to choose one that fluidizes with
It is preferable to use one having a softening point of about 40 to 250 ° C.

Next, the ink-affinitive substance constituting the fine particles is
Any material may be used as long as it exhibits good ink affinity, but paraffin wax, microcrystalline wax, beeswax, spermaceti wax, and ceramic wax are preferred in order to obtain excellent image receptivity and printing durability. , Carnauba wax, candelilla wax, montan wax, low molecular weight polyethylene wax, polypropylene wax, stearoamide, linolenic amide, lauryl amide, myristyl amide, methylene bis stearamide, ethylene bis stearamide wax, styrene resin, acrylic Resins, methacrylic resins, acrylonitrile resins, amino resins, coumarone-indene resins, rosin-modified phenol resins, terpene-modified phenol resins, urethane resins, xylene resins, ketone resins, and other lipophilic polymers alone. There is a copolymer of two or more of two or more thereof, or alkylnaphthalenes,
Synthetic oils such as alkylbiphenyl and alkylated terphenyl, petroleum fractions such as kerosene and naphtha, cottonseed oil, soybean oil,
Vegetable oils such as linseed oil, and the like, or a mixture of two or more of them is used. In particular, lipophilic polymers such as styrene resin, acrylic resin, methacrylic resin, acrylonitrile resin, amino resin, coumarone-indene resin, rosin-modified phenol resin, terpene-modified phenol resin, urethane resin, xylene resin, and ketone resin, alone or in combination. The above-mentioned copolymers or a mixture of two or more thereof can be mentioned.

There is no particular limitation on the method for producing the fine particles comprising the above-mentioned ink-affinitive substance, and the usual suspension polymerization method, emulsion polymerization,
A dispersion polymerization method or the like can be adopted. The preferred particle size of the fine particles is 0.01 to 200 μm, more preferably 0.01 to 200 μm.
To 50 μm, more preferably 0.05 to 10 μm,
In particular, if the particle size is too large, the resolution may deteriorate.

Further, the coating agent which may be used by coating the surface of the fine particles enhances the dispersibility of the fine particles in the ink-repellent binder as described above, and prevents the ink stain on the non-image portion to be printed. It exhibits an effect of further increasing the sharpness, and as the coating agent, an ink repellent substance which is the same as or different from the ink repellent binder can be used, and preferred are silicone resin, silicone acrylic resin, Silicone-containing polymers such as silicone epoxy resin, silicone alkyd resin, silicone urethane resin, modified silicone resin, and silicone graft resin, tetrafluoroethylene resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, tetrafluoroethylene-ethylene Copolymer resin, poly trifluoroethylene chloride, poly Kka vinylidene resins, acrylic ester derivative containing fluorine, or a polymer of methacrylic acid ester derivative, or a copolymer fluorine-containing polymers such as are exemplified. Among these, particularly preferred is an ink repellent polymer containing a silicone component.

The ink-philic fine particles coated with the above-mentioned coating agent are, for example, a coacervation method, interfacial polymerization, in-
It can be produced by a general method for producing microcapsules such as in situ polymerization, a method by polymerization such as suspension polymerization, emulsion polymerization, precipitation polymerization, dispersion polymerization, and a coating method such as spray drying method and dipping method. The preferred particle size of the coated particles is also in the same range as the preferred particle size of the ink-philic fine particles described above.

The preferred examples of the ink-affinitive substance and the ink-repellent substance constituting the image recording layer in the present invention are as described above. However, from the viewpoint of enhancing the sharpness of the printed image, the ink-affinity property and the ink repellency are given. "Contact angle to linseed oil (θ)" is used as a preferable measure of
<40 degrees], ink repellency is based on “θ ≧ 40 degrees”, and the combination of ink-philic substance and ink-repellent substance used is that the difference in contact angle (θ) is 10 degrees or more. It is better to select and combine some.

Next, as a method of forming the image recording layer, a binder made of an ink repellent substance is used as it is or diluted with an appropriate solvent as needed, and the ink-philic fine particles or the surface thereof is coated with the ink repellent substance. A method may be adopted in which the coated fine particles are dispersed and then coated on the substrate. When the coated fine particles are used, the coated fine particle dispersion obtained by the coacervation method, the interfacial polymerization method, or the like may be used as it is, and the ink repellent binder may be mixed with the dispersion and then coated on the substrate.

In this case, the preferable mixing ratio of the ink-philic fine particles and the ink-repellent binder is 5 to 300 of the ink-repellent binder to 100 of the ink-philic fine particles by weight.
More preferably, it is in the range of 10 to 150, and if the blending ratio of the ink repellent binder is insufficient, printing durability will deteriorate,
On the other hand, if the amount is too large, the resolution tends to deteriorate. Applicators, spray coaters, bar coaters, dip coaters, spin coaters, doctor blades and the like can be used for coating. After coating, if necessary, drying is carried out. At this time, heating with hot air at 30 to 120 ° C. for 30 minutes or more is preferable.

The preferable thickness of the obtained image recording layer is 0.05.
To 50 μm, more preferably 0.5 to 10 μm,
If it is too thin, it becomes difficult to obtain sufficient printing durability. On the other hand, if it is too thick, the image-processing portion during image recording processing becomes insufficiently ink-philic and it becomes difficult to obtain a clear image. The thickness of the substrate is not limited at all.

Next, when the planographic printing plate is manufactured by subjecting the planographic printing plate to an image recording process, heat is applied to the printed image corresponding portion from the front side, back side or both sides of the image recording layer.
By applying pressure or discharge energy and applying heat or the like only to the image recording portion, the ink-philic particles in the image recording layer are floated on the surface or are dissolved or diffused to expose the ink-philic substance on the surface. As a result, the surface of the image-processed part becomes ink-philic, while the surface of the non-image part where heat or the like is not applied is covered with a binder made of an ink-repellent substance, so that the ink-repellency remains unchanged. Thus, a lithographic printing plate having an ink-philic portion and an ink-repellent portion according to the recording pattern on the surface of the image recording layer can be obtained.

The energy used in the image recording process is not particularly limited as long as it can remove the ink-repellent binder on the surface of the image recording layer to expose the ink-philic substance on the surface, but it is general. As the method, a method utilizing heat and / or pressure or discharge energy is adopted.

As a method of using heat, for example, a method of heating with a thermal head, which has been remarkably widely used in facsimiles and printers recently, a method of using a hot pen, a method of pressing a mold, a method of irradiating with laser light and heating. Further, a method of irradiating with flash light and heating, a method of irradiating with ultraviolet rays, electron beams, high frequency waves or other electromagnetic waves can be used.

Particularly, from the viewpoint of sensitivity and operability, a method of heating with a thermal head or a method of heating by irradiating laser light is preferable. As the thermal head, the thermal head used in commercially available thermal facsimiles and thermal printers can be applied, and as the laser, semiconductor laser, helium / neon laser, argon laser, krypton laser, helium / cadmium laser, carbon dioxide gas can be used. There are lasers, excimer lasers, ruby lasers, glass lasers, YAG lasers, dye lasers and the like. When a laser is used, it is desirable that the fine particles contained in the image recording layer contain a light-heat converting substance such as a laser-sensitive dye or carbon black.

The heating temperature is not limited to a particular temperature, but is generally 50 to 400 ° C, preferably 60 to 300 ° C. When the heating temperature is low, the sensitivity is low, while when the heating temperature is high, the fine particles, the binder or the base material may be altered or destroyed. When a thermal head is used, the preferred heating time is 0.1 msec to 100 msec, more preferably 0.5 msec to 20 msec. When using a laser, the preferred exposure time per spot is
It is 0.5 nanosecond to 1 second, and more preferably 1 nanosecond to 1 millisecond. If the heating time is short, the resolution will be insufficient, and if the heating time is long, it will take a long time for plate making.

As the method using pressure, for example, a method using an impact printer such as a commercially available typewriter, serial wire dot type printer, ink ribbon type printer or the like can be used. When using both heating and pressurization, a method using the above thermal head or hot pen,
A method of pressing a pixel-shaped die or the like can be used.

As a method of using discharge, for example, there is a method of applying a voltage to a pin electrode or the like according to image information by scanning and writing the image portion on the plate material. In that case, the applied voltage is preferably about 60 to 80 V, and the recording speed is preferably 1 to 10 cm / sec from the viewpoint of resolution. The image recording layer may be covered with a cover film for the purpose of surface protection.

In the lithographic printing plate thus obtained, a pattern is formed on the surface of the image recording layer, in which the exposed image portion of the ink-philic substance and the exposed non-image portion of the ink-repellent substance are clearly distinguished. It is possible to perform clear printing without dampening water.

[0031]

The present invention is constituted as described above, and the image recording layer formed on the substrate is provided with a binder made of an ink repellent substance and fine particles made of an ink-affinitive substance or the fine particles made of an ink repellent substance. By making the coated fine particles dispersed by coating with, it is possible to change only the surface of the image processing part due to heat etc. to ink-philicity, which allows clear printing without dampening water. It is now possible to provide an original plate that gives a possible lithographic printing plate.

[0032]

【Example】

Example 1 Polyvinyl alcohol (trade name "PVA manufactured by Kuraray Co., Ltd."
-205 ") and 3.0 g of a polymerization initiator (benzoyl peroxide: manufactured by Wako Pure Chemical Industries, Ltd.) were dissolved in 220 g of deionized water, and a styrene monomer 60 was added thereto with a homogenizer.
g, 20 g of butyl acrylate and 20 g of divinylbenzene were dispersed. When the size of the droplet became about 5 μm, the stirring was stopped, 680 g of deionized water was added, the temperature was raised, and polymerization was carried out at 80 ° C. for 5 hours. After that, the reaction solution was cooled, and the precipitate obtained by centrifugation was dried at 30 ° C. for 12 hours under a nitrogen stream to obtain 90 g of particles.
Got The average particle size of the obtained particles was 5.5 μm.

10 g of the obtained particles were used as a binder R
Disperse 5.0 g of TV rubber (one-component type room temperature curing silicone rubber "KE42S" toluene 50% solution manufactured by Shin-Etsu Chemical Co., Ltd.) in 200 g of toluene, and deposit it on a polyethylene terephthalate film after drying. A lithographic printing plate precursor was obtained by coating with a bar coater so as to have a concentration of 10 g / m ² and then drying. This original version has a thermal facsimile (Pan
afax, UF-83) was used for thermal printing to obtain a printing plate. When 4 μl of linseed oil was dropped on the image portion and the non-image portion of this printing plate and the contact angles of the linseed oil were measured, the contact angle of the image portion was 16 ° and the contact angle of the non-image portion was 46 °. Offset printing machine (made by Gestettner) using this printing plate
When printing was performed without dampening water, clear printed images were obtained even after printing about 3000 sheets.

Example 2 Sila plane (reactive silicone "F" manufactured by Chisso Corporation)
M-0711 ", average molecular weight 1000) 25g, styrene monomer
20 g, butyl acrylate 5 g, and a polymerization initiator (Wako Pure Chemical Industries, Ltd. “V-59”) 0.5 g were added to normal hexane 50
After dissolving in g, the temperature was raised with stirring and polymerization was carried out at the reflux temperature for 20 hours. Then, normal hexane was distilled off under reduced pressure to obtain a silicone graft polymer (1) having an average molecular weight of 28,000. Next, the obtained silicone graft polymer (1) 5
g, 60 g of styrene monomer, 20 g of butyl acrylate, 20 g of divinylbenzene and 0.5 g of a polymerization initiator (“V-59”: same as above) were dissolved in 900 g of normal hexane, and the temperature was raised with stirring at reflux temperature for 10 hours. Polymerized. After that, the reaction solution is cooled and the precipitate obtained by centrifugation is subjected to a nitrogen stream at 30 ° C.
After drying for 12 hours, 85 g of coated particles having the silicone graft polymer (1) as a coating material were obtained. The average particle size of the obtained coated particles was 1.0 μm.

10 g of the obtained coated particles were mixed with 5.0 g of RTV rubber (“KE42S”: same as above) as a binder and toluene 20.
The solution was dispersed in a solution diluted with 0 g and applied on a polyethylene terephthalate film by a bar coater so that the weight after drying was about 10 g / m ² , and then dried to obtain a lithographic printing original plate. This original plate was heat-printed with a heat-sensitive facsimile (same as above) to obtain a printing plate. 4 in the image and non-image areas of this printing plate
When μl of linseed oil was dropped and the respective contact angles were measured, the contact angle in the image area was 16 ° and the contact angle in the non-image area was 58 °.
It was degree. Using this printing plate, we printed on an offset printing machine (same as above) without using fountain solution, and we obtained about 30
Even after printing 00 sheets, a clear image printed matter was obtained.

Example 3 Silaplane (reactive silicone "FM-0725" manufactured by Chisso Co., Ltd., average molecular weight 10000) 25 g, styrene monomer 20 g, butyl acrylate 5 g and polymerization initiator ("V-59": same) 0.5 g of the above) was dissolved in 50 g of normal hexane, and the temperature was raised with stirring to polymerize at reflux temperature for 20 hours. Then, normal hexane was distilled off under reduced pressure to obtain a silicone graft polymer (2) having an average molecular weight of 52000. Then, the obtained silicone graft polymer (2) 5
g, 60 g of styrene monomer, 20 g of butyl acrylate, 20 g of divinylbenzene and 0.5 g of a polymerization initiator (“V-59”: same as above) were dissolved in 900 g of normal hexane, then heated with stirring and refluxed for 10 hours. Was polymerized. The reaction liquid was cooled to obtain a dispersion liquid containing coated particles having the silicone graft polymer (2) as a coating material. When this dispersion liquid was sampled and analyzed, it was found that 90 g of the coated particles were contained in the dispersion liquid, and the remaining non-volatile components became a binder. The average particle size of the coated particles in the dispersion is 0.4 μ.
It was m.

The dispersion containing the obtained coated particles was dried on a polyethylene terephthalate film to give a weight of about 10 g /
A lithographic printing original plate was obtained by coating with a bar coater so as to have m ² and then drying. This original plate was heat-printed with a heat-sensitive facsimile (same as above) to obtain a printing plate. When 4 μl of linseed oil was dropped on the image portion and the non-image portion of this printing plate and the contact angles of the linseed oil and the non-image portion were measured, the contact angle of the image portion was 16 ° and the contact angle of the non-image portion was 56 °. With this printing plate,
When printing was performed using an offset printing machine (same as above) without using fountain solution, a clear image printed matter was obtained even after printing about 3000 sheets.

Example 4 Light Acrylate FA-108 (Kyoeisha Yushi Kogyo Co., Ltd.)
Fluorine acrylate (Molecular weight: 518) 25 g, Styrene monomer 20 g, Butyl acrylate 5 g and Polymerization initiator (“V-59”: same as above) 0.5 g were dissolved in normal hexane 50 g and then heated with stirring. Then, it was polymerized at reflux temperature for 15 hours. Then, normal hexane was distilled off under reduced pressure to obtain a fluorine-based graft polymer (3) having an average molecular weight of 10,000.
Next, 5 g of the obtained fluorine-based graft polymer (3), 60 g of styrene monomer, 20 g of butyl acrylate, 20 g of divinylbenzene and a polymerization initiator (“V-59”: the same as above).
After dissolving 5 g in 900 g of normal hexane, the temperature was raised and polymerization was carried out at reflux temperature for 10 hours while stirring. Then, the reaction liquid was cooled to obtain a dispersion liquid containing coated particles having the fluorine-based graft polymer (3) as a coating material. When this dispersion was sampled and analyzed, the dispersion contained 88 g of coated particles, and the average particle size of the coated particles in the dispersion was 0.8 μm.

20 g of RTV rubber (“KE42S”: same as above) as a binder was added to the obtained dispersion liquid containing coated particles to disperse the dispersion liquid, and the liquid was dried on a polyethylene terephthalate film to have a weight of about A lithographic printing plate precursor was obtained by coating with a bar coater so as to have a concentration of 10 g / m ² and then drying. This original plate was heat-printed with a heat-sensitive facsimile (same as above) to obtain a printing plate. When 4 μl of linseed oil was dropped on the image portion and the non-image portion of this printing plate to measure the contact angles, the contact angle of the image portion was 16 degrees, and the contact angle of the non-image portion was 6 degrees.
It was twice. Using this printing plate, we printed on an offset printing machine (same as above) without using fountain solution, and we obtained about 30
Even after printing 00 sheets, a clear image printed matter was obtained.

Example 5 Silicone graft polymer (1) 5 synthesized in Example 2
g, 40 g of styrene monomer, 40 g of acrylonitrile, 20 g of butyl acrylate and 3 g of a polymerization initiator (“V-59”: same as above) were dissolved in 900 g of normal hexane, and the temperature was raised with stirring to polymerize at reflux temperature for 10 hours. Let Then, the reaction liquid was cooled to obtain a dispersion liquid containing coated particles. When this dispersion was sampled and analyzed, 92 g of the coated particles were contained in the dispersion, and the average particle size of the coated particles in the dispersion was 0.4 μm.

20 g of RTV rubber (“KE445” manufactured by Shin-Etsu Chemical Co., Ltd.) as a binder was dispersed in the dispersion liquid containing the obtained coated particles, and the polyethylene terephthalate film had a weight of about 10 g / m ² after drying. To obtain a lithographic printing original plate. This original plate was heat-printed with a heat-sensitive facsimile (same as above) to obtain a printing plate. 4μ in the image area and non-image area of this printing plate
When linseed oil (1) was dropped to measure the contact angles of the linseed oil, the contact angle of the image portion was 14 degrees, and the contact angle of the non-image portion was 55.
It was degree. Using this printing plate, we printed on an offset printing machine (same as above) without using fountain solution, and we obtained about 30
Even after printing 00 sheets, a clear image printed matter was obtained.

Example 6 In Example 2, the binder RTV rubber (same as above) was replaced with silicone varnish (trade name "TS" manufactured by Toshiba Silicone Co., Ltd.).
R-144 "), the same operation as in Example 2 was repeated to obtain a lithographic printing plate, and plate making and printing were performed, and a printed matter with a clear image was obtained even after printing about 3000 sheets. . The contact angles of the image portion and the non-image portion with respect to the linseed oil in this printing plate were 14 degrees and 50 degrees.

Example 7 The same procedure as in Example 1 was repeated except that a typewriter (brother, HR-20) was used in place of the heat-sensitive facsimile in the plate making method in Example 2 to carry out plate making and printing. However, a clear image printed matter was obtained even after printing about 3000 sheets. The contact angles of the image portion and the non-image portion with respect to the linseed oil in this printing plate were 16 degrees and 58.
It was degree.

Example 8 20 g of coated particles synthesized in the same manner as in Example 2, 0.2 carbon black (trade name “MA-7” manufactured by Mitsubishi Kasei Co., Ltd.)
g, RTV rubber (same as above) 10 g and methanol 200 g 3
A dispersion liquid was obtained by dispersing together with mm-sized glass beads for 2 hours with a paint shaker (manufactured by Toyo Seiki Seisaku-sho, Ltd.). The obtained dispersion was applied to a polyethylene terephthalate film by a bar coater so that the weight after drying was about 10 g / m ² , and then dried to obtain a lithographic printing original plate.
The resulting lithographic printing plate precursor was image-exposed at a scanning speed of 3 m / e and a scanning pitch of 20 μm with a beam diameter 1 / e ² of 25 μm × 25 μm focused by a 120 mW argon laser.
When this was used as a printing plate and printing was carried out in an offset printing machine (same as above) without using dampening water, clear printed matter was obtained even after printing about 3000 sheets. The contact angle of linseed oil between the image and non-image areas of this printing plate was 1
It was 6 degrees and 58 degrees.

Example 9 In Example 8, a pin electrode with an applied voltage of 80 V was applied to the lithographic printing original plate instead of the argon laser, and 8 cm /
An image was formed at an image density of 32 lines / mm at a recording speed of 2 seconds to obtain a printing plate. When using it as a printing plate and using an offset printing machine (same as before) without dampening water,
Even after printing 3000 sheets, clear image prints were obtained. still,
The contact angles of the image portion and the non-image portion with respect to the linseed oil in this printing plate were 16 degrees and 58 degrees.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Etsukuni Mori             5-8 Nishiomitabicho, Suita City, Osaka Prefecture             Central Research Institute of Nippon Shokubai (72) Inventor Masatoshi Yoshida             5-8 Nishiomitabicho, Suita City, Osaka Prefecture             Central Research Institute of Nippon Shokubai

Claims (2)

[Claims] 1. A lithographic printing plate precursor comprising a substrate and an image recording layer provided on the substrate, wherein the image recording layer comprises fine particles of an ink-philic substance dispersed in a binder of an ink-repellent substance. An original plate for lithographic printing characterized by being a thing. 2. The lithographic printing plate precursor as claimed in claim 1, wherein the fine particles of an ink-philic substance are coated with an ink-repellent substance which is the same as or different from the ink-repellent substance constituting the binder and dispersed in the binder. .