JPS6217218B2 - - 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 baking can be manufactured without adversely affecting printing characteristics, and in particular, fine powder that is heat-fused to the printing plate surface to improve vacuum adhesion is used. maintenance and management (thermal control) of the heating process is easy;
A photosensitive material that can uniformly heat-fuse fine powder onto the surface of a printing plate without being affected by uneven thickness of the photosensitive printing plate support, and preventing the generation of wrinkles on the printing plate due to heating. The present invention relates to a method for producing a 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. This tends to impair the affinity for ink, and the matte layer also tends to dissolve in the developer and fatigue the developer. Also, in Japanese Patent Application Laid-open No. 51-111102,
A photosensitive printing plate having a coating layer provided on its surface in the form of a minute pattern is disclosed. 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. Furthermore, Japanese Patent Application Laid-Open No. 51-98505 discloses a method of applying a wax-like or finely powdered resin having mold releasability in order to solve the problem that the coating layer for improving vacuum adhesion stains the film original plate. Disclosed. 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 equipment and process for providing the solid or fine powder resin coating layer are complicated, resulting in high coating costs and difficult manufacturing maintenance and management.

On the other hand, there is a method in which solid powder such as talc is dispersed and adhered to the surface of the photosensitive printing plate by mechanical means on the photosensitive layer side surface of the photosensitive printing plate before the contact baking process (referred to as powdering). There are 53 printed magazines
(10), 23 (1970), Inoue, Iino, Printing Information, 33(11),
90 (1973), disclosed in Ishiyama et al. This powdering improves vacuum adhesion by simply applying powder to prevent back transfer of printed matter or commercially available talc with a spray gun or puff, and also solves the developability problem seen in the conventional example. Although it can solve problems such as background stains and manufacturing problems, it also has the following drawbacks. In other words, 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. Moreover, it is unfavorable from the viewpoint of working environment, and cleaning of peripheral equipment required after the powdering process is a problem that cannot be ignored in terms of efficiency. In addition, the solid powder on powdered photosensitive printing plates easily falls off during handling.
This may cause contamination of the surrounding area, and as a result, the expected vacuum adhesion may not be obtained.

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 process equipment becomes cheaper,
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 mixed indiscriminately with parts of the photosensitive printing plate which can obtain the vacuum adhesion but whose printing characteristics 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. Furthermore, it has been found that even when a heating roll that can solve this problem is used, the following problems still occur. In other words, aluminum plates, which are generally used as supports for photosensitive printing plates, tend to have uneven thickness in the width direction during the stretching process during the manufacturing process, resulting in a state in which the central portion in the width direction is thinly stretched. There is a tendency to Due to this, when heat-sealing fine powder is heat-sealed to the surface of a photosensitive printing plate using the support, fusing failure occurs at the center in the width direction, resulting in poor vacuum adhesion. In order to solve this problem, if the temperature of the heating roll is raised to a high temperature, the photosensitive layer on both sides of the photosensitive printing plate in the width direction may be adversely affected by heating, and the photosensitive printing plate may It was found that wrinkles may appear on the skin.

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 photosensitive printing plate that can uniformly heat-fuse solid powder without being affected by plate thickness unevenness of the photosensitive printing plate support and without adversely affecting the photosensitive layer. An object of the present invention is to provide a manufacturing method.

A sixth object of the present invention is to provide a method for producing a photosensitive printing plate in which the temperature at which fine powder can be thermally fused to the surface of the printing plate can be easily controlled.

A seventh object of the present invention is to prevent wrinkles from forming on a photosensitive printing plate due to a heating process, and to prevent uneven thermal fusion of solid powder caused by this. The object of the present invention is to provide a method for manufacturing a plate.

The eighth 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 ninth 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 and other objects mentioned below of the present invention are to provide a surface of a photosensitive printing plate with a directional diameter of 0.5 mm.
0.005-0.5g of ~40μ heat-fusible fine powder per ^1m2
In addition to supplying it so that it is evenly distributed and depositing it,
At the time of supplying the fine powder, or before or after supplying, the back side of the photosensitive printing plate is brought into contact with a preheating roll and preheated, and then the front side of the photosensitive printing plate has a surface with good mold releasability. This is achieved by bringing the heat-fusible fine powder into contact with a heating roll to heat-fuse 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 the figure, a photosensitive printing plate 1 is continuously run at a constant speed.
Preheating roll 4A whose back side 2A side is appropriately heated
Surface 2B of printing plate 1 after being preheated by contacting with
(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, the heating roll 4B has a surface with good mold releasability and a roll with good heat insulation (and good elasticity).
The printing plate 1 is caused to pass between the printing plate 1 and the pressure roll 5, and during this passage, the surface 2B of the printing plate 1 is brought into pressure contact with the heating roll 4B. As a result, the heat-fusible fine powder uniformly dispersed and adhered to the printing plate surface 2B is melted and fused to the printing plate surface 2B.

In addition, 6 in the figure is a roll provided as necessary, and the surface of the printing plate 1 that has passed between the heating roll 4B having a surface with good mold releasability and the pressure roll 5 with good heat insulation property is further removed. It is provided to make contact with the heating roll 4B (portion A), and its purpose is to increase the contact area of the surface of the printing plate with the heating roll 4B.

In a preferred embodiment of the present invention,
Although the case has been described in which the preheating roll 4A is provided before the step of uniformly dispersing and adhering the heat-fusible fine powder to the printing plate surface 2B, the location of the preheating roll 4A is not limited to this, It may be placed at any position before the printing plate comes into contact with the heating roll 4B, after the fine powder supply step, or at the same time. Furthermore, the number of preheating rolls 4A does not need to be singular as shown in the drawings, and a plurality of preheating rolls may be provided as necessary. Even when the plurality of preheating rolls 4A are arranged, the arrangement position of each preheating roll 4A is not limited.

The preheating roll 4A used in the present invention assists the heating roll 4B having a surface with good mold releasability in the next step in thermally fusing the heat-fusible fine powder to the printing plate surface 2B. One of the purposes is to prevent the printing plate surface 2B from being rapidly heated by the preheating roll 4B, causing thermal expansion of the photosensitive printing plate itself and causing undesirable results. It is desirable that the heating temperature for the printing plate be set at least lower than the heating temperature by the heating roll 4B. In order to achieve the above-mentioned objects of the present invention, the upper limit of the heating temperature by the preheating roll 4A used in the present invention is limited so that the surface temperature of the printing plate immediately before contacting the heating roll 4B becomes the following temperature. This is desirable. That is, the second transition point of the heat-fusible fine powder used (measured by a differential scanning calorimeter (in degrees Celsius); the same applies hereinafter). ] plus 50°C, more preferably up to the second transition point of the fine powder plus 20°C. Further, in order to achieve the various objects of the present invention, the lower limit of the heating temperature by the preheating roll 4A used in the present invention is set as follows:
It is desirable to limit the surface temperature of the printing plate immediately before contacting the heating roll 4B to the following temperature. That is, the temperature is the second transition point of the heat-fusible fine powder used minus 30°C, more preferably the second transition point of the fine powder minus 10°C. Therefore, the heating temperature by the preheating roll 4A should be adjusted appropriately within the range of the above lower limit to upper limit temperature, depending on the type of photosensitive printing plate to be formulated, the influence on the photosensitive layer, the type and amount of the fine powder used, etc. It is desirable to establish

After powdering the heat-fusible fine powder used in the present invention on the surface of the photosensitive layer side of the photosensitive printing plate,
Any material may be used as long as it can be thermally fused to the surface by heat and has a diameter in the fixed direction of 0.5 to 40 microns. This heat-fusible fine powder has a first-order transition point (a value measured by a differential scanning calorimeter) lower than the first-order transition point (a value measured by a Koka type flow tester) or a second-order transition point (a value measured by a differential scanning calorimeter) of the photosensitive layer. A solid powder consisting essentially of a substance or composition having a value of
The second-order transition point and the second-order transition point are higher than 40°C,
And the first-order transition point or second-order transition point of the substance or composition 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 ester,
Examples include polystyrene, polystyrene derivatives, copolymers of these monomers, polyvinyl methyl ether, epoxy resins, phenol resins, polyamides, 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 strong alkaline aqueous solutions such as silicates include hydroxyethylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyvinyl alcohol, polyacrylic acid, polyacrylic ester, polystyrene derivatives and acrylic acid. Alternatively, polyacrylic esters, polyacrylamides, copolymers containing polystyrene, phenolic resins, etc. having phenolic or alcoholic hydroxyl groups are preferably applied. Photosensitive printing plates that use ring image liquids using organic solvents such as alcohols, glycols, and ketones include cellulose derivatives, polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetate, polyvinylidene chloride, polyacrylic acid, and polyvinyl pyrrolidone. Acrylamide, polyacrylic ester, polystyrene, copolymers of two or more of acrylic acid, acrylamide, acrylic ester, and styrene monomers, epoxy resins, phenolic resins, and the like are preferably used. In addition, matting agents that are widely used to roughen 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 used is not particularly limited as long as it has a diameter within the above-mentioned direction, and may be spherical or the above-mentioned fine powder material crushed into an irregular shape by a ball mill, jet mill, etc. You can use things that have become old.

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 Fluidized bed electrostatic spray and electrostatic fluidized bed described in Plastic Eng. Handbook (1976),
Methods such as air spray, brush, and puff 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 the fine powder hardly adheres to the surface of the heating roll during this heat-sealing. 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 roughened and the roughened 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 above-mentioned fluororesin or silicone resin, is preferably 100 μm or more in order to facilitate the control of heat transfer when the above-mentioned 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 temperature at which the printing plate is preheated by the preheating roll 4A, An appropriate temperature is selected depending on the type, melting point, and amount of the fine powder to be heat-sealed, the type of photosensitive printing plate, etc.

The heating temperature by the heating roll used in the present invention is appropriately selected as described above, but it is preferably selected so that the surface temperature of the printing plate immediately after leaving the heating roll falls within the following temperature range. be done.
That is, the temperature ranges from the second-order transition point of the fine powder used to the first-order transition point of the fine powder plus 100°C.

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 lithographic printing plates and intaglio printing plates. , 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 various objects of the present invention can be achieved, and in particular, as a method for fusing heat-fusible fine powder to the surface of a photosensitive printing plate, heating is performed on the back surface of the printing plate in advance. The fine powder is thermally fused by contacting a heated preheating roll with the surface of the printing plate to preheat it, and then bringing the heating roll, which has a heated surface with good mold releasability, into contact with the surface of the printing plate, so that only the heating roll is used. Not only is it easier to control the heating temperature necessary for the above-mentioned heat fusion compared to when using a heating roll, but the printing plate is heated gradually and slowly, so the fine powder can be heated at a low temperature by the heating roll. It can heat-fuse the plate and at the same time prevent the occurrence of wrinkles caused by rapid thermal expansion of the photosensitive printing plate, thus preventing the contact between the photosensitive printing plate and the heating roll, which is the main cause of wrinkles. It is possible to prevent uneven adhesion of fine powder caused by defects, and furthermore, it is possible to obtain a photosensitive printing plate with excellent vacuum adhesion without adversely affecting the photosensitive layer due to heating. It exhibits the effect of easily producing photosensitive printing plates of uniform quality without being affected by uneven thickness of the support.

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.

On the other hand, photosensitive printing plate (Sakura PS version SLP, 0.3mm
Thickness) is run continuously at a constant speed of 10 m per minute, and the surface of the printing plate is preheated to 80°C by contacting a heated preheating roll from the back side. Using a powder feeder that supplies a fixed amount of powder, 0.05g per ^1m2 of printing plate surface
Spread it evenly so that it adheres. Thereafter, as shown in the figure, 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 coated 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 110°C, and the heating roll 4 is insulated from the heat-shrinkable tube. The contact pressure with the elastic roll 5 was set to 1.2 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 the figure) was further increased to 70 mm. A sample of the present invention was obtained by bringing the fine powder into contact with the heating roll 4 so as to thermally fuse 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 30 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 11/4 m for 3 minutes, a 1% aqueous solution of trisodium silicate was used. The film was developed by immersing it in water for 45 seconds. 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 printing plate surface 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]

The figure is a schematic diagram of all steps showing a typical embodiment of the method for producing a photosensitive printing plate of the present invention. In the figure, 1 is a photosensitive printing plate, 2A and 2B are the back and front surfaces of the printing plate, 3 is a powder feeder, 4A is a preheating roll, and 4B is a heating roll having a surface with good mold releasability.

Claims (1)

[Claims] 1. Supply heat-fusible fine powder with a directional diameter of 0.5 to 40μ to the surface of a photosensitive printing plate at a rate of 0.005 to 0.5 g per 1 m ² and uniformly disperse and adhere it, and at the time of supply or at the time of supply of this fine powder. Before or after, the back side of the photosensitive printing plate is brought into contact with a preheating roll to preheat it, and then the front side of the photosensitive printing plate is brought into contact with a heating roll having a surface with good mold releasability. A method for producing a photosensitive printing plate, which comprises heat-sealing the heat-fusible fine powder to the surface of the printing plate.