JPH11263080A - Lithographic printing original plate and method for forming lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing original plate and a method for manufacturing a lithographic printing plate from the original plate to improve an image quality by providing good conveyability, preservability, scratchability, good fog preventive performance. SOLUTION: The lithographic printing original plate comprises a recording layer having a hydrophilic property, a decreasing solubility to water and/or swelling properties on a support changing according to a heat in such a manner that a roughness parameter Ra of a laser non-contact type surface roughness meter on a surface of an opposite side to a side having the layer is 1 μm or less. The method for forming a lithographic printing plate comprises the step of recording the original plate with a high illuminance light having an intensity per unit area of 10 W/cm<2> or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a lithographic printing plate precursor,
And a method of preparing a lithographic printing plate. In particular, the present invention relates to a method for preparing a lithographic printing plate precursor and a lithographic printing plate capable of making a plate without water development or development processing. A lithographic printing original plate creates a lithographic printing plate by recording various information on its recording layer.The created lithographic printing plate can be used to print on various media such as paper based on the recorded information. Is what you do.

[0002]

2. Description of the Related Art Various methods have been proposed for preparing a lithographic printing plate without water development or development. JP-B-39-1743 describes a heat-sensitive recording material using an apparent film of a discontinuous polymer having a film-forming temperature of 40 ° C. or higher. However, the heat-sensitive recording material using this apparent film is very weak and easily peeled off since no film is formed before exposure.

Japanese Patent Publication No. 44-22957 discloses a heat-sensitive material containing a light-absorbing substance for converting absorbed light into heat and a hydrophobic thermoplastic polymer particle dispersed in a hydrophilic resin at a ratio of more than 1: 1. A method of exposing the layer to obtain an image based on the difference in hydrophilicity and water permeability is described, and the above-mentioned publication describes that polyethylene is preferably used as the hydrophobic thermoplastic resin particles.

Japanese Patent Publication No. 63-42953 discloses a heat-sensitive recording material containing an ionomer resin dispersion and a water-soluble polymer, and is used as a printing master.

Japanese Patent Application Laid-Open No. Hei 9-127683 describes a lithographic printing plate in which a self-water-dispersible thermoplastic resin particle layer which can be made lipophilic by heat is formed on the surface of a hydrophilic substrate.

However, the recording material applied to such a printing plate has a thermoplastic surface, so that when the material, which is usually in the form of a sheet, is conveyed, conveyance defects such as two-sheet feeding are likely to occur. . In addition, blocking was liable to occur during the storage of the laminate, saying that they would stick together.

In order to avoid such a problem, it is conceivable that the surface (the surface on the side having the recording layer) is provided with, for example, a matting property to roughen the surface. It is considered that by roughening the surface sufficiently, transport failure or blocking can be avoided.

The roughness of the recording layer side is described in
-38192, Ra (described later) is 0.3 to 2.0.
Recording layers with μ have been proposed. In addition,
Japanese Patent Application Laid-Open No. 211092 describes that, for a lithographic printing original plate having a recording layer whose hydrophilicity changes due to heat, the surface (the surface having the recording layer) preferably has a roughness of 0.5 μm or less. Have been. JP-A-1-295894
Japanese Patent Application Laid-Open No. H10-216, discloses a lithographic printing plate precursor having a recording layer whose hydrophilicity is also changed by heat, and its surface (the surface having the recording layer) has a smoothness of 2,000 seconds or more using an Oken smoothness meter. Are disclosed. These are all descriptions to the effect that a smooth surface is preferable. As described above, in this type of conventional technology, some studies have been made on the smoothness of the front surface, but no studies have been made on the smoothness of the back surface.

In the technique of roughening the surface having the recording layer, which is the surface, as in the above-mentioned prior art, the influence on the recording layer cannot be avoided. That is, by roughening the surface, transport failure or blocking can be avoided, but on the other hand, adversely affect image characteristics and printing performance.

As described above, a lithographic printing original plate has a good transportability, that is, it can be smoothly transported without causing a transport failure such as two-sheet feeding, and has a good storage stability. It does not cause blocking or the like, and it is desirable that the rubbing property is good, that is, it is stable to receive damage or the like even when rubbing at the time of transportation, etc., and not only that, but naturally, recording of image information, and It is required that the image performance and the printing performance be good as a means for reproducing the image. However, as described above, in the prior art, these could not be satisfied. Further, since image information is recorded and reproduced, it is desired that fogging such as pressure fogging does not occur even when pressure is applied during lamination or the like, and good fog prevention is desired. It is also desired that the image quality can be further improved.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has good transportability, preservability, and abrasion, and has good fog prevention performance and improved image quality. It is an object of the present invention to provide a lithographic printing plate that can be achieved, and a method for producing a lithographic printing plate from the printing plate.

[0012]

The object of the present invention is to provide a recording medium having a recording layer whose hydrophilicity changes by heat on a support, and a surface opposite to the recording layer having a laser non-contact surface roughness. This is achieved by a lithographic printing plate precursor characterized in that the roughness parameter Ra of the thickness meter is 1 μ or more.

Another object of the present invention is to provide a recording medium having a recording layer whose hydrophilicity is changed by heat on a support, and the surface opposite to the recording layer is provided with a roughness measured by a laser non-contact type surface roughness meter. A lithographic printing original plate having a parameter Ra of 1 μ or more,
This is achieved by a method of preparing a lithographic printing plate characterized in that recording is performed with high illuminance light having an intensity per unit area of 10 W / cm ² or more.

Another object of the present invention is to provide a recording medium having a recording layer whose solubility in water and / or swelling property is reduced by heat on a support, and a surface opposite to the side having the recording layer is not in contact with the laser. The roughness parameter Ra by the mold surface roughness meter is 1μ
With the lithographic printing plate precursor characterized by the above,
Achieved.

Another object of the present invention is to provide a recording medium having a recording layer whose solubility in water and / or swelling property is reduced by heat on a support, and a surface opposite to the side having the recording layer is not in contact with the laser. The roughness parameter Ra by the mold surface roughness meter is 1μ
This is achieved by a method for preparing a lithographic printing plate characterized in that the lithographic printing plate precursor described above is recorded with high illuminance light having an intensity per unit area of 10 W / cm ² or more.

In order for the roughness parameter Ra of the surface opposite to the surface having the recording layer (hereinafter also referred to as the front surface) to be within the scope of the present invention, Such surface roughening can be achieved by performing an appropriate surface treatment on the surface opposite to the side having the recording layer (the back surface of the support). For example, on the back of the support,
Matting can be applied.

The present inventors roughen the back surface of the support, which is the side opposite to the side having the recording layer, by matting or the like to thereby improve image performance and printing performance. The present inventors have found that the transportability and the blocking property can be improved without affecting the present invention, and have led to the present invention. Further, with regard to the back surface roughening treatment (for example, mat processing), it has been found that, depending on the shape of the roughness, for example, pressure fogging may occur due to concentration of stress on the protrusions of the mat during lamination. The present inventors have found that there is a roughness range in which is not generated, and completed the present invention.

In the present invention, furthermore, by carrying out a slight matting process on the surface of the recording layer and a strong matting process on the back surface, it is possible to achieve both transportability / blocking and pressure fogging at a high level, which is the most preferable. . As the degree of surface roughening applied to the surface side, the surface roughness is 0.3 to
2μ is preferred. If the surface Ra exceeds 2μ, image defects tend to occur easily, and if it is 0.3μ or less, it is difficult to obtain a roughened effect.

Hereinafter, the present invention will be described in more detail.
The lithographic printing plate precursor according to the present invention is a recording material having a recording layer whose hydrophilicity is reduced by heat, and has a back surface roughness parameter Ra of 1 μ or more. Another lithographic printing plate precursor according to the present invention is a recording material having a recording layer whose solubility in water and / or swelling property is reduced by heat, and a roughness parameter Ra of the back surface is 1 μm.
That's all.

The back surface roughness parameter Ra of any lithographic printing plate precursor according to the present invention is at least 1 μm, preferably at least 1.5 μm. More preferably, it is 3 μm or less. If it is 1 μm or less, the effect of improving transportability and blocking is not sufficient. If it exceeds 3 μm, there is a possibility that pressure fogging may occur.

Each of the lithographic printing original plates according to the present invention has a back side cutoff value of 150 × 111 at a cutoff value of 2 μm.
Preferably, the peak count per μ is 10 or less. This value is, for example, RST / PLUS (WYC
O company).

The lithographic printing plate precursor according to the present invention forms a lithographic printing plate by recording information on its recording layer.

In the method of preparing a lithographic printing plate according to the present invention, the lithographic printing plate precursor according to the present invention is recorded with high illuminance light having an intensity per unit area of 10 W / cm ² or more.

In the embodiment of the present invention, the light source for exposure may be a xenon lamp, a halogen lamp, a tungsten lamp, a laser, an LED, a CRT, or the like. Can be used without restriction. Light sources that can be suitably used include a flash light source and a laser light source. As a flash light source, emission half width is 10m
and a xenon flash having an emission intensity of 1 W / cm ² or more is preferable. A preferred laser light source has an output of 50
Examples thereof include an argon laser, a helium neon laser, and a semiconductor laser having a power of at least mW, and various laser beams described below can be used. In the case where image exposure is performed with a laser, the intensity of laser light per unit area is preferably 10 W / cm ² or more.

As the exposure method using such a light source, a contact exposure and a scanning exposure can be typically given. In the case of close contact exposure, the original transmission original and the recording material are brought into close contact with each other, and exposure is performed from the transmission original side with the high illuminance light as described above. In this case, the exposure time is 10 ms.
The following is preferred. If the exposure time is longer than 10 ms, the image quality tends to deteriorate due to the diffusion of the thermal pattern.

When a laser is used for exposure, light can be focused in a beam form, and scanning exposure can be performed according to image data. Therefore, direct writing can be performed without using a mask material. When a laser is used as a light source, the exposure area can be easily reduced to a very small size, and high-resolution image formation can be performed. As laser light source, argon laser, He-Ne gas laser, YA
Any of a G laser, a semiconductor laser and the like can be suitably used. Among these, the use of a semiconductor laser or a YAG laser is more preferable because a high output suitable for the lithographic printing plate material of the present invention can be incorporated into a small device at a relatively low cost.

As a scanning exposure method using a laser, there is an exposure method using a cylinder outer surface scan, a cylinder inner surface scan, a plane scan, or the like. In scanning the outer surface of the cylinder, laser irradiation is performed while rotating a drum around which the recording material is wound around the outer surface. In this case, generally, the rotation of the drum is defined as main scanning, and the movement of the laser beam is defined as sub-scanning. In the cylinder inner surface scanning, a recording material is fixed on the inner surface of a drum, and a laser beam is irradiated from the inside. In this case, generally, the main scanning is performed in the circumferential direction by rotating a part or the whole of the optical system, and the sub-scanning is performed in the axial direction by linearly moving the part or the whole of the optical system in parallel to the axis of the drum. Do. In the planar scanning, the main scanning of the laser light is generally performed by combining a polygon mirror or a galvanometer mirror with an fθ lens, and the sub-scanning is performed by moving the recording medium. Scanning of the outer surface of the cylinder and scanning of the inner surface of the cylinder are easy to improve the accuracy of the optical system, and are suitable for high-density recording.

The recording layer of the lithographic printing material (original plate) according to the present invention may be a material whose hydrophilicity, solubility in water, swelling property and the like are changed by heating.

As the layer according to the present invention, whose hydrophilicity is reduced by heating, any layer can be used as long as the hydrophilicity is reduced by a chemical or physical reaction by heating. As a specific configuration, see Japanese Unexamined Patent Application Publication No. 9-127
No. 683, by irradiating the surface of a hydrophilic substrate with a self-water-dispersible thermoplastic resin particle layer capable of being made lipophilic by heat, or by irradiating with a laser beam as described in JP-A-51-63704. It is possible to use a hydrophilic polymer or the like that cures the irradiated portion, becomes hydrophobic or lipophilic, and can be changed to absorb ink.

In order to further enhance the hydrophilicity and water retention, the hydrophilicity-reducing layer may contain solid particles. Examples of the solid particles include inorganic fine particles and organic fine particles. Examples of usable inorganic fine particles include silica gel, calcium carbonate, titanium oxide, zinc oxide, barium sulfate, talc, clay, kaolin, acid clay, activated clay, and alumina. Examples of the organic fine particles include resin fine particles such as fluororesin fine particles, guanamine resin fine particles, acrylic resin fine particles, and silicon resin fine particles.

These particles are preferably subjected to a hydrophilic surface treatment.

The preferred particle size of these particles is 0.01
μ to 10 μ. More preferably, 0.5μ-5μ
It is. When the particle size is 0.5 μm or less, it may be difficult to increase water retention. If it exceeds 5 μm, the film strength of the obtained coating film may be insufficient.

Further, the hydrophilicity-reducing layer may contain a light-to-heat conversion material that absorbs light and generates heat.
In the practice of the present invention, when the hydrophilic layer described below does not contain a light-to-heat conversion substance, it is preferable that the hydrophilicity-reducing layer contains a light-to-heat conversion substance.

The preferred light-to-heat conversion material varies depending on the light source, but is preferably a material that absorbs light and efficiently converts it to heat. For example, when a semiconductor laser is used as a light source, a material having an absorption band in the near infrared region is used. Preferably, as a near-infrared light absorber, for example, organic compounds such as carbon black or cyanine, polymethine, azurenium, squarium, thiopyrylium, naphthoquinone, anthraquinone dyes, phthalocyanine, azo,
Thioamide-based organometallic complexes and the like are preferably used.
Specifically, JP-A-63-139191 and JP-A-64-3
No. 3547, JP-A-1-160683 and 1-280
No. 750, No. 1-293342, No. 2-2074,
3-26593, 3-30991, 3-34
No. 891, No. 3-36093, No. 3-36094,
3-36095, 3-42281, 3-97
No. 589, No. 3-103476 and the like. These can be used alone or in combination of two or more.

The method of roughening the surface on the opposite side of the recording layer of the lithographic printing plate according to the present invention is optional. When the surface roughening is performed by coating, the coating solution is substantially free from physical or chemical adverse effects on the support,
Optional. The roughened layer may be, for example, a layer that is mechanically matted or a resin layer that contains a matting agent. As a method of mechanically matting the surface of the roughened layer, a method of applying the roughened layer so as to obtain a coating layer having an uneven pattern, and a method of mechanically roughening the surface to form a roughened layer There is a method to do.

Specific examples of the above method include a method in which the roughened layer is coated with a gravure roll having an uneven pattern, and a method in which resin particles are sprayed and thermally fused to obtain an uneven pattern. As a specific method described above, there is a method in which after a roughened layer is provided, a mat is formed by pressing with a pressure roller having an uneven surface having a hardness higher than the hardness of the roughened layer. The support itself may be formed into a mat by applying pressure.

When a metal support is not used as the support, the chargeability can be suppressed and the handleability can be improved by adding a conductive layer to the roughened layer on the back surface.

The thickness of the roughened layer is preferably 2 to 30 μm. If the roughened layer is thinner than 2μ, or 3
If it exceeds 0 μm, it may be difficult to obtain desired roughness.

In the case of a resin layer containing a matting agent, the particle size of the particles of the matting agent to be used is preferably in the range of 1 to 30 μm, more preferably 2 to 10 μm.

As the filler that can be used as the matting agent, the same solid particles as those used in the recording layer can be used.

According to the preferred embodiment of the present invention, the surface side of the recording layer is also roughened. When the front side is also roughened, the roughness on the back side can be suppressed. Regarding the surface roughening, the back surface roughening can be similarly performed.

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. However, needless to say, the present invention is not limited by the embodiments described below.

Examples 1 to 4 and Comparative Examples 1 to 4 In this example, first, a lithographic printing original plate sample was obtained as follows. That is, a thickness of 10 having a gelatin undercoat layer
A polyethylene terephthalate (PET) film of 0μ was used as a support, and a wire bar was formed on this film by using a wire bar.
The following coating liquid for forming a recording layer was applied so that the weight after drying was 20 mg / dm ² . After the application, this recording material was dried at 50 ° C. or lower to prepare a sample according to the present invention.

Recording Layer Forming Coating Solution Carbon Black 40% Aqueous Dispersion Solids 10 parts by weight 10% Gelatin aqueous solution Solids 10 parts by weight Sylysia 435 (solid particles) 30 parts by weight Chemipearl S650 (ionomer resin 20% aqueous dispersion Liquid) 15 parts by weight as solids Sumireze Range 613; 5 parts by weight (melamine resin) manufactured by Sumitomo Chemical Co., Ltd.

On the back surface of the support, a mat layer was formed by applying the following coating solution to roughen the back surface. Coating solution for mat layer formation for backside rough surface MX-300 (Soken Chemical) Polymethylmethacrylate (PMMA) particle aqueous dispersion (particle size 5μ)

As described above, the samples of Examples 1 to 4 shown in Table 1 were obtained. The surface roughness parameter Ra and the back surface roughness parameter Ra of each sample are shown in the table. The method for measuring the roughness parameter Ra was as follows. Measurement method of roughness parameter Ra WYKO optical three-dimensional surface roughness meter: RST pl
The surface roughness Ra was measured using s. The measurement conditions are
Under conditions of an objective lens × 40 and an intermediate lens × 1.0, 11
A 1 × 150 μm field of view was measured at N = 5 and the average was determined.

The lithographic printing plate precursor thus produced was recorded on the recording layer thereof with a semiconductor laser. Thus, a recorded planographic printing plate was obtained. This could be printed on a sheet-fed printing press without any processing after recording. Table 1 shows the evaluation of the transportability, blocking property, image defect, and pressure fogging of each sample. The evaluation methods of each transportability, blocking property, image defect, and pressure fog were as follows.

Method for Measuring Conveyance The laser exposure apparatus shown in FIG. 1 (Japanese Patent Laid-Open No. 9-22624)
A transport test was performed using the method described in FIG. In FIG. 1, reference numeral 1 denotes sheet mounting means, 2 denotes a drum,
Reference numeral 3 denotes a contacting unit, 4 denotes an exposing unit, 5 denotes a peeling unit, 6 denotes a sheet removing unit, 7 denotes a light irradiation device, reference numeral 11 denotes an insertion table, 12a to 12e denotes a pair of conveying rollers, 21 denotes a drum peripheral wall, and 22 denotes a drum peripheral wall. Decompression holes, 31 and 32 are belt conveyors, 52
a to 52c guide plates, 51 and 63 are discharge tables, 61 and 62
Is a separation claw constituting a sheet removing means. The transportability was evaluated as a transport failure due to a two-sheet feed from a plate feeding mechanism (not shown) or a peel failure from the exposure drum. A 20-sheet transport test was performed, and the number of defective transports was evaluated as follows. ○: 0 sheets, Δ: 1-2 sheets, ×: 3 sheets or more.

Blocking property measuring method The sheets cut into a size of 20 cm × 20 cm are overlapped, and 50 ° C.
For 24 hours. The number of sheets from the top that did not cause blocking was evaluated as follows. ○: 100 or more, Δ: 20 to 99, ×: 19 or less.

Image Defect Measuring Method The ink was applied with PS plate developing ink SPO-1 (manufactured by Konica Corporation), and a solid image portion (a portion exposed to laser) was prepared.
The number of white spots per 10 cm × 10 cm was evaluated as follows.・ ・ ・: 5 or less, Δ: 6 to 10, ×: 10 or more.

Pressure fogging measurement method The ink was applied using PS plate developing ink SPO-1 (manufactured by Konica Corporation), and the number of stains per 10 cm × 10 cm of the non-image area was evaluated as follows. ○: 0, Δ: 4 or less, ×: 5 or more.

[0052]

[Table 1] 表面 Surface roughness Backside roughness Transportability Blocking Image defect Pressure fog ──────────────────────────────────── Example 1 0.5 2.0 ○ ○ ○ ○ Example 2 0.2 1.5 △ △ ○ ○ Example 3 0.2 2.5 ○ ○ ○ △ Example 4 1.5 1.5 ○ ○ △ ○ Example 1 0.2 0.1 or less × × ○ ○ Example 2 3.0 0.1 or less ○ ○ × ○ Example 3 1.5 0.1 or less × × △ ○ Example 4 0.5 0.1 or less × × ○ ○ ────────────────────────────────── ──

[0053]

As described above, the printing original plate of the present invention,
And a method for producing a lithographic printing plate from the printing plate precursor,
It has good transportability, storability, and abrasion, and also has good fog prevention performance, and has the effect of improving image quality.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a laser exposure apparatus used for measuring and evaluating transportability in Examples.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheet mounting means 2 Drum 3 Adhesion means 4 Exposure means 5 Peeling means 6 Sheet removal means (separation claw) 7 Light irradiation device

Continuing on the front page (72) Inventor Takaaki Kuroki 1st Konica Corporation, Sakuracho, Hino-shi, Tokyo

Claims (4)

[Claims] 1. A support having a recording layer whose hydrophilicity is changed by heat on a support, and a surface opposite to the side having the recording layer has a roughness parameter Ra measured by a laser non-contact type surface roughness meter.
A lithographic printing plate precursor having a particle size of 1 μ or more. 2. A support having a recording layer whose hydrophilicity changes by heat on a support, and a surface opposite to the side having the recording layer has a roughness parameter Ra measured by a laser non-contact type surface roughness meter.
A method for preparing a lithographic printing plate, characterized in that a lithographic printing plate precursor having a particle size of 1 μ or more is recorded with high illuminance light having an intensity per unit area of 10 W / cm ² or more. 3. A support having a recording layer whose solubility in water and / or swelling property is reduced by heat on a support, and a surface opposite to the side having the recording layer has a laser non-contact type surface roughness. A lithographic printing plate precursor having a roughness parameter Ra of 1 μ or more measured by a thickness meter. 4. A support having a recording layer whose solubility in water and / or swelling property is reduced by heat on a support, and a surface opposite to the side having the recording layer has a laser non-contact surface roughness. A method for preparing a lithographic printing plate, characterized by recording a lithographic printing plate precursor having a roughness parameter Ra of 1 μ or more by a high-intensity light having an intensity per unit area of 10 W / cm ² or more.