JPS6217219B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing photosensitive printing plates.
Specifically, photosensitive printing plates with excellent vacuum adhesion during contact printing can be manufactured without adversely affecting printing characteristics, are easy to maintain and manage during manufacturing, and can be uniformly manufactured using inexpensive equipment. The present invention relates to a method for producing a photosensitive printing plate that can easily produce a high quality photosensitive printing plate.

Conventionally, in order to closely bake a film base plate onto a photosensitive printing plate, a vacuum baking frame was generally used, and the film base plate and photosensitive printing plate were stacked between the glass plate and rubber sheet of the printing frame, and the glass plate and A method (referred to as a vacuum contact method) is used in which the film original plate and the photosensitive printing plate are brought into close contact with each other by creating a vacuum between them and the rubber sheet. In this vacuum adhesion method, various means are known for achieving sufficient adhesion over the entire surface to be adhered in a short time.

That is, for example, JP-A-50-125805 discloses a photosensitive printing plate provided with a matte layer on its surface. Although vacuum adhesion is improved by this method, the matte layer provided on the surface of the photosensitive layer prevents the developer from penetrating and deteriorates developability, and a part of it remains in the image area after development. The matte layer tends to inhibit the affinity for ink, and furthermore, the matte layer has a strong tendency to dissolve in the developer and fatigue the developer. Further, Japanese Patent Application Laid-Open No. 111102/1983 discloses a photosensitive printing plate having a coating layer provided on its surface in the form of a minute pattern. Although this method improves the adverse effect on developability (delay in development) compared to the above-mentioned method of providing a matte layer, the coated layer of the minute pattern is not completely removed when developed with a tired developer, so-called " Furthermore, a large amount of binder or matting agent is required to obtain sufficient vacuum adhesion, which tends to fatigue the developer, and the equipment and process for forming the coating layer are complicated. In addition to increasing the coating cost, it may not be possible to coat a coating layer with a minute pattern depending on the composition, thickness, surface properties, etc. of the photosensitive layer. Also, in Japanese Patent Application Laid-open No. 51-98505,
In order to solve the problem that a coating layer for improving vacuum adhesion stains a film original plate, a method is disclosed in which a wax-like or finely powdered resin having mold releasability is applied. However, this coating layer does not adhere firmly to the surface of the photosensitive printing plate and easily falls off, and if it is applied uniformly over the entire surface to ensure strong adhesion, it not only has the disadvantage of impeding the penetration of the developer, but also The disadvantages are that the coating, folding and process for providing a solid or fine powder resin coating layer are complicated, resulting in high coating costs, and manufacturing maintenance and management are difficult.

On the other hand, there is a method (referred to as powdering) in which a solid powder such as talc is dispersed and adhered to the surface of the photosensitive printing plate by mechanical means before the contact baking process. Print magazine 53(10),
23 (1970), Inoue, Iino, Printing Information, 33(11), 90
(1973), as disclosed in Ishiyama et al. This powdering improves vacuum adhesion using a simple method such as spraying powder to prevent back transfer of printed matter or commercially available talc with a spray gun or puff, and also improves the developability problem seen in the conventional example. Although this method can solve problems such as background smudges and manufacturing problems, it also has the following drawbacks. That is, powdering is generally applied when using photosensitive printing plates, and the powdering operation scatters solid powder into the plate-making work room, polluting the work environment and causing various problems in the plate-making process. This is not only unfavorable from the standpoint of working environment hygiene, and cleaning of surrounding equipment required after the powdering process is also a problem that cannot be ignored in terms of efficiency. Furthermore, the solid powder on the powdered photosensitive printing plate is likely to fall off during handling, contaminating the surrounding area, and therefore may not provide the expected vacuum adhesion.

Therefore, the present inventors thought of solving the above-mentioned drawbacks of the conventional powdering method by fixing the powdered solid powder to the surface of the printing plate. Continued research on heat fusion methods to achieve this goal.
As a result, when hot air or thermal radiation from an infrared heater is used as a method of thermally fusing solid powder to the surface of a printing plate, the entire photosensitive printing plate becomes high temperature due to the heat required for thermal fusing, and the photosensitive layer In addition, from the viewpoint of manufacturing equipment, the heating process equipment is large-scale, which increases manufacturing costs, and maintenance and management during manufacturing is complicated. In this case, the expected vacuum adhesion may not be obtained because the solid powder dispersed and adhered to the surface of the printing plate is scattered by the hot air, or a large amount of solid powder is used for photosensitive printing in anticipation of the scattering by the hot air. It has also been found that if the solid powder is attached to the plate in advance, a larger amount of solid powder than expected may be thermally fused to the surface of the printing plate, which may adversely affect the printing properties. On the other hand, when using heat conduction using a heating roll, etc. as another method for thermally fusing solid powder to the surface of a printing plate, it is only necessary to melt the solid powder and there is no need to heat the entire printing plate. While it is cheaper to write the process,
Because it is necessary to bring a heating roll that conducts heat to the solid powder into contact with the solid powder, a portion of the heat-molten solid powder is fused to the heating roll, and a uniform amount of solid powder is not thermally fused to the surface of the printing plate. Parts of the photosensitive printing plate where the expected vacuum adhesion cannot be obtained are indiscriminately mixed with parts of the photosensitive printing plate which can obtain the vacuum adhesion but whose printing properties are adversely affected by the thermal fusion of solid powder that is greater than expected. It has been found that the maintenance and control of the heating process becomes extremely difficult.

As mentioned above, it has been found that if the amount of solid powder that is thermally fused to the surface of the printing plate is too large, it will adversely affect the printing properties, and if the amount is too small, the expected vacuum adhesion properties cannot be obtained. At the same time, it was found that the printing characteristics and vacuum adhesion were also affected by the particle size of the solid powder to be heat-sealed.

The present invention has been made based on the above findings, and the first object of the present invention is to firmly heat-fuse a solid powder that improves vacuum adhesion to the surface of a photosensitive printing plate. An object of the present invention is to provide a method for producing a photosensitive printing plate in which the powder does not fall off during handling as in the conventional powdering method.

A second object of the present invention is to provide a method for producing a photosensitive printing plate that can produce a photosensitive printing plate with excellent vacuum adhesion during contact printing without adversely affecting its printing properties. be.

A third object of the present invention is to avoid raising the entire printing plate to a high temperature by using hot air or thermal radiation such as an infrared heater in the heating process for thermally fusing solid powder.
Therefore, it is an object of the present invention to provide a method for producing a photosensitive printing plate that does not adversely affect the photosensitive layer.

A fourth object of the present invention is to be able to heat-fuse a solid powder in a uniform amount on the surface of a photosensitive printing plate in the heating process to heat-fuse it, and to obtain a printing plate of uniform quality. An object of the present invention is to provide a method for manufacturing a photosensitive printing plate.

A fifth object of the present invention is to provide a method for manufacturing a photosensitive printing plate that uses a heating device that is simple and inexpensive from the viewpoint of manufacturing equipment, and that can be manufactured at low manufacturing cost.

A sixth object of the present invention is to provide a method for producing a photosensitive printing plate, in which maintenance and control of the heating process during production is easy, and a large quantity of photosensitive printing plates of uniform quality can be continuously obtained. That's true.

The above object of the present invention and other objects mentioned below are such that the surface of a photosensitive printing plate has a uniform direction diameter of 0.5 to 0.5 to 1.
After supplying 0.005 to 0.5 g of heat-adhesive fine powder of 40 μm ^per square meter and uniformly dispersing and adhering it, the front side of the photosensitive printing plate was brought into contact with a heating roll having a surface with good mold release properties. This is accomplished by heat-sealing the heat-fusible fine powder onto the surface of the photosensitive printing plate.

According to a preferred embodiment of the present invention, as shown in FIG.
(on the side with the photosensitive layer), heat-fusible fine powder with a directional diameter of 0.5 to 40 μ is applied per 1 m ² using the powder feeder 3.
After supplying a fixed amount of 0.005 to 0.5 g and uniformly dispersing and adhering it, a heating roll 4 having a surface with good mold releasability and a pressure roll 5 with good heat insulation (and good elasticity) (the diameter of which is The diameter of the printing plate 1 may be the same as or different from that of the roll (the same applies hereinafter), and the surface 2 of the printing plate 1 is brought into pressure contact with the heating roll 4 during this passage. As a result, the heat-fusible fine powder uniformly dispersed and adhered to the printing plate surface 2 is melted and fused to the printing plate surface 2.

According to another preferred embodiment of the present invention, as shown in FIG. A roll 6 (suitably one with good heat insulation properties) is provided to bring the surface of the printing plate 1 that has passed between the pressure roll 5 into further contact with the heating roll 4 (portion A). The aim is to increase the contact area of the printing plate surface with the printing plate.

Furthermore, according to another preferred embodiment of the present invention, as shown in FIG. A roll 7 for bringing the surface of the plate 1 into contact with the heating roll 4 (portion marked B)
It is to establish.

Furthermore, according to another embodiment of the present invention, as shown in FIG. 4, before and after the heating roll 4,
The purpose is to provide the rolls 6 and 7 to increase the contact area with the heating roll 4.

The heat-fusible fine powder used in the present invention can be powdered onto the photosensitive layer side surface of a photosensitive printing plate and then heat-fused to the surface by heat, and has a diameter in a direction of 0.5 to Any material with a diameter of 40μ is sufficient. This heat-fusible fine powder has a first-order transition point lower than the first-order transition point (value measured with a Koka type flow tester) of the photosensitive layer.
A solid powder consisting essentially of a substance or composition having a second-order transition point or a second-order transition point (as measured by differential scanning calorimetry), or whose surface layer consists essentially of the substance or composition. is preferred, more preferably the first transition point and the second transition point of the substance or composition are higher than 40°C, and the first transition point or the second transition point of the substance or composition is higher than 40°C
The second-order transition point is lower than the first-order transition point of the photosensitive layer. Furthermore, in the present invention, only the heat-fusible fine powder powdered on the photosensitive layer side surface of the photosensitive printing plate is rapidly heated and melted without heating the entire photosensitive printing plate to a high temperature. It is also possible to use heat-fusible fine powders having a first-order transition point higher than the first-order transition point of the photosensitive layer. Preferred specific examples include polyvinyl acetate, polyvinylidene chloride, polyethylene oxide, polyethylene glycol, polyacrylic acid, polyacrylamide, polyacrylic acid ester, polystyrene and polystyrene derivatives, copolymers of these monomers, polyvinyl methyl ether, and epoxy. Examples include resin, phenolic resin, polyamide, polyvinyl butyral, and the like.

The heat-fusible fine powder used in the present invention is preferably one that is soluble in a developer for photosensitive printing plates. For example, photosensitive printing plates that can be treated with strongly alkaline aqueous solutions such as silicates include hydroxyethylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyvinyl alcohol, polyacrylic acid, polyacrylic ester, polystyrene derivatives and acrylic Polyacrylic esters, polyacrylamides, copolymers containing polystyrene, phenolic resins, and the like having acidic or phenolic or alcoholic hydroxyl groups are preferably used. Photosensitive printing plates that use developers using organic solvents such as alcohols, glycols, and ketones include cellulose derivatives, polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetate, polyvinylidene chloride, polyacrylic acid, and polyacrylamide. , polyacrylic ester, polystyrene, a copolymer consisting of two or more of acrylic acid, acrylamide, acrylic ester, and styrene monomers, epoxy resin, phenolic resin, and the like are preferably used. In addition, commonly used matting agents for roughening the surface of objects (for example, silica, zinc oxide, titanium oxide, zirconium oxide, alumina, polymethyl methacrylate, polystyrene,
A material in which the surface of a fine solid powder such as a phenol resin is wrapped in the above heat-fusible fine powder material may also be used.

In the present invention, the heat-fusible fine powder supplied to the surface of the photosensitive printing plate is limited to a powder having a diameter in the direction of 0.5 to 40 μm (more preferably a diameter in the direction of 1 to 17 μm). That is, the diameter in the fixed direction is 0.5μ
When the heat-fusible fine powder has a diameter of less than 40 μm, there is almost no improvement in vacuum adhesion, and when the diameter in the fixed direction is larger than 40 μm, the reproducibility of small halftone dots deteriorates.

In order to adjust the particle size of the heat-fusible fine powder used in the present invention within the above-mentioned range, a generally known classification method may be followed. Further, the shape of the heat-fusible fine powder to be used is not particularly limited as long as it has a diameter in the above-mentioned direction, and may be spherical or the fine powder material described above that has been crushed by a ball mill, jet mill, etc. A fixed shape can be used.

In the present invention, the amount of heat-fusible fine powder supplied to the surface of the photosensitive printing plate is 1 m ² of the surface of the photosensitive printing plate.
It is required to be evenly distributed and deposited at 0.005 to 0.5 g per coat. However, if more than 0.5 g of fine powder per 1 m ² is fused to the surface of the printing plate, the reproducibility of small halftone dots deteriorates, and if less than 0.005 g of fine powder is fused to the surface of the printing plate per 1 m ² , the vacuum adhesion is poor. This is because the improvement in performance is not sufficient. According to the method of the present invention, the heat-fusible fine powder uniformly dispersed and adhered to the surface of the printing plate in the above amount is transferred to the printing plate in almost the same amount by contact with a heating roll having good mold releasability. Since it is thermally fused to the surface, it is sufficient to uniformly disperse and adhere it to the surface of the printing plate within the above-mentioned amount range.

In the present invention, in order to uniformly disperse and adhere the heat-fusible fine powder to the printing plate surface in the above amount,
In addition to using the powder feeder, known methods such as JJ Sokol, RC Hendrickson, Plastic Engineering Handbook, P. 426,
P.431 (1976) [JJSokol and RCHendrickson
In addition to the electrostatic spray, electrostatic fluidized bed, etc. described in Plastic Eng. Handbook (1976), methods using air spray, brush, puff, etc. may be used.

The heating roll used in the present invention, which has a surface with good mold releasability, refers to the heating roll on which the surface of the printing plate, on which the heat-fusible fine powder is evenly distributed and adhered in the above amount, is brought into contact with the roll. Any material may be used as long as it serves to heat-seal the powder to the surface of the printing plate and that during this heat-sealing, the upper fine powder hardly adheres to the surface of the heating roll. Specifically, the surface of a known heating roll is lined with a fluororesin such as Teflon (trade name), the surface of a heating roll is made rough and the rough surface is impregnated with a fluororesin, A heating roll coated with a heat-shrinkable fluororesin tube such as tetrafluoroethylene-hexafluoropropylene copolymer, or a silicone resin heating roll may be used. The thickness of the resin layer having good mold releasability, such as the fluororesin or silicone resin, is preferably 100 μm or more in order to facilitate control of heat transfer when the fine powder is thermally fused. Also, if it is too thick, it is not preferable from the viewpoint of thermal efficiency. Further, it is desirable that the heating roll having a surface with good mold releasability has a smooth surface.

In the present invention, by bringing the printing plate surface into contact with a heating roll having a surface with good mold releasability, heat-fusible fine powder uniformly dispersed and adhered to the printing plate surface is thermally melted onto the printing plate surface. In the present invention, heat fusion means that the fused fine powder is fixed to such an extent that it will not easily fall off due to friction during normal plate-making operations. In particular, when undesirable foreign matter adheres to the surface of the photosensitive printing plate, it is preferable that the fine powder is fixed to such an extent that the fine powder will not be removed along with the foreign matter by wiping the surface with a cloth or the like. . Therefore, the heating temperature by the heating roll may be within a necessary and sufficient temperature range to thermally melt the fine powder and fix it to the printing plate surface to the above degree, and the type of fine powder to be thermally fused, An appropriate temperature is selected depending on the melting point, amount, type of photosensitive printing plate, etc.

In the present invention, the photosensitive printing plate on which the heat-fusible fine powder is fused is basically one in which a photosensitive layer is provided on a support, and includes a lithographic printing plate and a letterpress printing plate. , known photosensitive printing plates used for making printing plates such as intaglio printing plates. As a support, for example, in the case of a photosensitive lithographic printing plate, an aluminum plate, a composite sheet in which an aluminum sheet is bonded to a polyethylene terephthalate film as described in Japanese Patent Publication No. 18327/1980, etc. are preferable. Further, in the case of a photosensitive letterpress printing plate, aluminum plates, iron plates, etc. are preferable.
The above-mentioned supports include those subjected to known surface treatments, and may also have an undercoat layer. Further, the photosensitive layer provided on the support may be any known type in which the photosensitive material changes in solubility or swelling property in a developer before and after exposure.

According to the present invention, the surface of the photosensitive printing plate has a unidirectional diameter.
Heat-fusible fine powder of 0.5-40μ 0.005-0.5 per ^m2
After supplying the fine powder to a uniform dispersion and adhesion, the surface side of the photosensitive printing plate is brought into contact with a heating roll having a surface with good mold releasability to thermally fuse the fine powder to the surface of the printing plate. , unlike heating means using thermal radiation such as hot air or infrared heaters, the entire printing plate is not heated and exposed to high temperatures, so the fine powder of the specific particle size can be identified without adversely affecting the photosensitive layer due to heating. It can be firmly and uniformly heat-fused and fixed on the surface of a photosensitive printing plate by a certain amount, and it can also be improved in terms of printing characteristics such as halftone dot reproducibility. The vacuum adhesion during contact baking can be significantly improved without impairing the printing characteristics of It is possible to uniformly heat-fuse the fine powder on the surface of the printing plate in an amount that maintains the above-mentioned good printing characteristics without scattering the heat-fusible fine powder as in the case of the heat-fusible powder and without adhering the heat-fusible fine powder to the heating roll. A photosensitive printing plate of uniform quality can be obtained using simple and inexpensive manufacturing equipment, and the manufacturing equipment is easy to maintain and manage, and the manufacturing cost is low.

Hereinafter, specific examples of the present invention will be given, but the embodiments of the present invention are not limited thereto.

Example: A styrene-acrylic acid-butyl acrylate (ratio: 45:30:25) copolymer was crushed and classified using a zigzag classifier manufactured by Alpime, and heat-sealed with a directional diameter of 0.5 to 40μ. A fine powder was obtained. A known photosensitive printing plate (Sakura PS plate SLP, 0.3mm
Using a powder feeder, the powder was uniformly spread and adhered to the surface of the printing plate (with a thickness of 0.05 g/m ² of the printing plate surface). Thereafter, as shown in FIG. 2, it was passed between a heating roll 4 and a pressure roll 5, and then placed on a roll 6 and conveyed. That is, a heating roll covered with a heat-shrinkable tube made of tetrafluoroethylene-hexafluoropropylene copolymer having a thickness of 0.5 mm is used, the surface temperature of the heating roll is maintained at 185°C, and the heating roll 4 is insulated from the heat-shrinkable tube. Elastic roll 5
The contact pressure with the printing plate was set to 3 kg per 1 cm of the width of the printing plate, and after passing between the two rolls, the contact length (the length of the part marked A in Fig. 2) was 70
A sample of the present invention was obtained by bringing the fine powder into contact with the heating roll 4 so that the thickness of the fine powder was 1 mm, and heat-sealing the fine powder to the surface of the printing plate.

The obtained photosensitive printing plate (sample) required 1 minute and 20 seconds for vacuum adhesion during contact baking, whereas the photosensitive printing plate before applying the formulation of the present invention required 2 minutes and 20 seconds. It only took 10 seconds.

The following method was used for the contact baking. That is, a photographic film (500
x 700 mm) and the sample (800 x 1003 mm) were vacuum-adhered using a horizontal vacuum baking frame KD-P1 type baking frame made by Kamo Electric Laboratory.

After exposing the photosensitive printing plate samples of the present invention and the photosensitive printing plate before applying the treatment method of the present invention to a 2KW metal halide lamp from a distance of 1-1/4 m for 3 minutes, 45% in aqueous solution
It was immersed for a second and developed. The thermally fused fine powder had no effect on development, and a positive image exactly like the original was obtained. The printing performance of each of the above printing plate samples was completely equivalent. That is, no effect was observed on development and printing performance (both image areas and non-image areas) by fusing the heat-fusible fine powder onto the surface of the photosensitive printing plate.

Next, in the above embodiment of the present invention, the amount of heat-fusible fine powder to be uniformly dispersed and adhered to the surface of the printing plate was set to 1.
When the same prescription as above was used except that the amount was changed to 0.6g and 0.004g ^per m2, the reproducibility of small halftone dots worsened when the amount was 0.6g ^{per m2} , and 0.004g ^per m2
It was found that the improvement in vacuum adhesion was insufficient in the case of the amount of g.

Next, in the above embodiment of the present invention, the same recipe as above was used except that the heat-fusible fine powder to be uniformly dispersed and adhered to the surface of the printing plate had a diameter in the direction of more than 40μ and less than 0.5μ. As a result, the reproducibility of small halftone dots deteriorated for samples using fine powder with a diameter of more than 40μ, and the vacuum adhesion was not improved for samples using fine powder with a diameter of less than 0.5μ. It was found to be sufficient.

[Brief explanation of the drawing]

FIGS. 1 to 4 are schematic diagrams showing the entire process of the method for producing a photosensitive printing plate of the present invention, and show four representative embodiments. In the figure, 1 is a photosensitive printing plate, 2 is its surface, 3 is a powder feeder, and 4 is a heating roll having a surface with good mold releasability.

Claims (1)

[Claims] 1. After supplying heat-fusible fine powder with a directional diameter of 0.5 to 40μ to the surface of the photosensitive printing plate at a rate of 0.005 to 0.5 g per 1 m ² and uniformly dispersing it, the surface side of the photosensitive printing plate is A method for producing a photosensitive printing plate, which comprises bringing the photosensitive printing plate into contact with a heating roll having a surface with good mold releasability to thermally fuse the heat-fusible fine powder to the surface of the photosensitive printing plate.