JPS6217222B2 - - 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, maintenance and management during manufacturing are easy, and photosensitive printing plates can be easily manufactured. The present invention relates to a method for producing a photosensitive printing plate that can easily obtain a photosensitive printing plate of uniform quality without being affected by the physical properties of the support and without adversely affecting the photosensitive layer.

Conventionally, in order to closely bake a thick film plate onto a photosensitive printing plate, a vacuum baking frame was generally used, the original film plate and the photosensitive printing plate were stacked between the glass plate of the printing frame and a rubber sheet, and the glass plate 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 by creating a vacuum between the film plate and the rubber sheet. In this vacuum adhesion method, various means are known for obtaining 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 (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, Print Information, 33
(11), 90 (1973), as 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 undesirable from the viewpoint of working environment hygiene, and cleaning of peripheral equipment required after the powdering process is 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, causing 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 perspective of manufacturing equipment, the heating process equipment is large-scale and manufacturing costs are high, 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 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 heat-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 has been found that the printing characteristics and vacuum adhesion are also influenced by the particle size of the solid powder to be heat-sealed.

Based on the above-mentioned knowledge, the present inventors continued research to eliminate the shortcomings of the conventional vacuum adhesion improvement technology described above, and as a result, the present inventors found that a unidirectional diameter is applied to the surface of a photosensitive printing plate.
Heat-fusible fine powder of 0.5-40μ 0.005-0.5 per ^m2
After the surface side of the photosensitive printing plate is brought into contact with a heating roll having a surface with good mold releasability, the heat-adhesive fine particles are applied onto the surface of the photosensitive printing plate. We have developed a technology to thermally fuse powder.

Even after the inventors have developed this new technology,
As we continued our research to produce photosensitive printing plates of higher quality and uniform quality, we discovered the following problems. 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, and the center part in the width direction is stretched thin. When a hot roll with good mold releasability is brought into contact with the surface of a photosensitive printing plate using such a support to thermally fuse the heat-fusible fine powder to the surface of the printing plate, Poor fusion of the fine powder may occur at the center of the printing plate surface, and if the temperature of the heating roll is increased to eliminate the fusion defect at the center, the edges of the printing plate surface may It has been found that this not only adversely affects the photosensitive layer in the photosensitive layer, but also causes wrinkles to occur due to rapid thermal expansion of the photosensitive printing plate, which is likely to cause uneven fusion.

SUMMARY OF THE INVENTION Therefore, the first object of the present invention is to firmly heat-fuse a heat-fusible fine powder that improves vacuum adhesion to the surface of a photosensitive printing plate, so that the powder can It is an object of the present invention to provide a method for producing a photosensitive printing plate that does not cause the particles to fall off.

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 characteristics. be.

The third object of the present invention is to be able to heat-fuse the solid powder in a uniform amount on the surface of the 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.

The fourth object of the present invention is to produce a photosensitive printing plate without being affected by the physical properties of the support of the photosensitive printing plate, and without having any adverse effect on the photosensitive layer due to heating.
It is an object of the present invention to provide a method for producing a photosensitive printing plate that allows a printing plate of high quality and uniform quality to be obtained.

A fifth object of the present invention is to make it easier to maintain and manage the heating process during production than when using a heating method other than heating rolls, and to continuously produce a large quantity of photosensitive printing plates of uniform quality. An object of the present invention is to provide a method for producing a photosensitive printing plate that can be obtained.

The above object of the present invention and other objects described below are to form a surface of a photosensitive printing plate with a directional diameter of 0.5 to
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. When heat-sealing the heat-fusible fine powder to the surface of the photosensitive printing plate, both edge portions of the surface of the photosensitive printing plate are heated to a temperature lower than the heating temperature of the center of the surface of the photosensitive printing plate. This is achieved by heating at temperatures.

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.
On the surface 2 (the side with the photosensitive layer) of the
After uniformly dispersing and adhering 0.5 to 40 μ heat-fusible fine powder using a powder feeder at a rate of 0.005 to 0.5 g per 1 m ² , heat it to create a surface with good mold release properties. The roll 4 is passed between the pressure roll 5 (the diameter of which may be the same as or different from the diameter of the heating roll. The same applies hereinafter) having good heat insulation (and good elasticity), and printing is performed during this passage. Plate 1 surface 2
is brought into pressure contact with the heating roll 4. During this heating, both edge portions 2A of the printing plate surface 2,
2A is heated at a temperature lower than the heating temperature of the central portion 2B of the printing plate surface. As a result, the heat-fusible fine powder uniformly dispersed and adhered to the printing plate surface 2 can be melted equally in the center portion 2B and both edge portions 2A, and can be evenly fused to the printing plate surface 2.

In this specification, when bringing the printing plate surface 2 into contact with the heating roll 4 and heat-sealing the heat-fusible fine powder to the surface 2, both edge portions 2A, 2A are connected to the center portion 2.
Heating at a temperature lower than the heating temperature of B means that the heating temperature of both ear ends 2A, 2A is lower than the heating temperature of center part 2B, and the heating temperature of both ear ends 2A, 2A is lower than the heating temperature of central part 2B. This means that the temperature is equal to the temperature.

In addition, 6 in the figure is a roll (suitably one with good heat insulation properties) provided as needed, and is a roll that covers the surface 2 of the printing plate 1 that has passed between the heating roll 4 and the pressure roll 5. Furthermore, it is brought into contact with the heating roll 4,
The contact area of the printing plate surface 2 with the heating roll 4 is increased. Therefore, this roll 6 may be provided on the front side of the heating roll 4 to increase the contact area in the same way as above, or the heating roll 4
may be placed before and after to increase the contact area.

Further, in the present invention, the printing plate 1 may be preheated before the surface 2 of the photosensitive printing plate contacts the heating roll 4 (as a specific example, roller 7 in the figure is a heating roll, One example is a preheating method in which the back surface 3 of the printing plate is brought into contact with the printing plate.However, the timing of this preheating may be at the same time as the step of adhering the heat-fusible fine powder to the surface of the printing plate, or before or after that. ).

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 transition point (measured by a differential scanning calorimeter) or a second transition point (measured by a differential scanning calorimeter) lower than the first transition point (measured by a Koka type flow tester) of the photosensitive layer. A solid powder consisting essentially of a substance or composition having The second-order transition point is 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, 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 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 having phenolic or alcoholic hydroxyl groups, polyacrylamide, copolymers containing polystyrene, phenolic resins, etc. 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, 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 will deteriorate, and if less than 0.005 g of fine powder is fused per 1 m ² , the vacuum adhesion will be poor. This is because the improvement in performance is not sufficient. According to the method of the present invention, the heat-fusible fine powder that has been uniformly dispersed and adhered to the surface of the printing plate in the above-mentioned 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 RC
Hendrickson, Plastic Eng. Handbook (1976)]
In addition to the electrostatic spray, electrostatic fluidized bed, etc. described in , methods using air spray, brush, puff, etc. may be used.

The heating roll having a releasable surface used in the present invention refers to a printing plate surface on which the heat-fusible fine powder is uniformly dispersed and adhered in the above amount.
Any material may be used as long as it serves to thermally fuse the fine powder to the surface of the printing plate when brought into contact with the roll, and that hardly any of the fine powder 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 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, when the heating roll 4 is brought into contact with the printing plate surface 2 on which heat-fusible fine powder is evenly distributed and adhered, and the fine powder is thermally fused to the printing plate surface 2, the printing plate surface is Any method can be used to heat the ends of both ears 2A at a temperature lower than the heating temperature of the central part 2B. For example, specific examples of preferable heating methods include the following.

That is, a method of cooling both ends of the heating roll 4 by blowing cold air or the like on both ends of the heating roll 4 (portions that contact both edge parts 2A, 2A of the printing plate surface 2), or a method of cooling both ends of the heating roll 4; Insulating material made of a material with low thermal conductivity (for example, a tube-shaped body with a thickness of 0.1 to 10 mm with low thermal conductivity,
A method of heating the photosensitive printing plate by coating or wrapping it with a filament (such as a filament with a diameter of 0.1 to 10 mm) so that the temperature at both ends of the photosensitive printing plate is lower than the temperature at the center (including isothermal);
Alternatively, a roll whose diameter decreases from the center to both ends (a so-called crown roll) is used as the heating roll 4, so that both ends 2A, 2A of the printing plate surface are larger than the center 2B. A method of strongly avoiding contact with the heating roll 4,
Alternatively, if a pressure roll 5 is used, the pressure roll 5 may be used as the crown roll, or a roll before and/or after the heating roll 4 (for example, a front roll 7 and/or a rear roll 6).
When using a method in which at least one of the rolls is provided as the crown roll, and a method in which the printing plate 1 is preheated, blowing cold air to both edge portions of the preheated printing plate, Both ear ends 2
A, 2A is brought into contact with the printing plate surface 2 to the heating roll 4 after the temperature of the central portion 2B is lower than the preheating temperature of the central portion 2B,
Examples include a method of preheating 2A to a temperature lower than central portion 2B.

In the present invention, when heating both edge portions 2A, 2A of the printing plate surface at a temperature lower than the heating temperature of the central portion 2B by the above-mentioned method,
The heating temperature of A is 0°C higher than the heating temperature of central part 2B.
It is desirable to lower the temperature by ~20°C, more preferably by 0°C ~10°C. Bare, both ear ends 2A,
If the heating temperature of the end portions 2A is higher than the heating temperature of the center portion 2B, the above-mentioned drawbacks will occur and the object of the present invention cannot be achieved, and the heating temperature of the end portions 2A, 2A of both ears will be higher than the heating temperature of the center portion 2B. This is because if the temperature drops below 20° C., it may become unnecessary to fuse the ends 2A, 2A of both ears.

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 above-mentioned objects can be achieved, and in particular, after uniformly dispersing and adhering a specific amount of heat-fusible fine powder of a specific particle size to the surface of a photosensitive printing plate, When the surface of the printing plate is brought into contact with a heating roll having a surface with good mold releasability and heat-sealed, both edges of the surface of the photosensitive printing plate are heated at a temperature lower than the heating temperature of the center of the surface of the photosensitive printing plate. Since the heating is carried out at a high temperature, it is possible to obtain a photosensitive printing plate with excellent vacuum adhesion without being affected by the physical properties of the support of the photosensitive printing plate. To prevent poor fusion in the center of the printing plate or adverse effects of heating on the photosensitive layer at both edges of the printing plate, which occurs when thermally fusion fine powder is thermally fused with a heating roll without As a result, a photosensitive printing plate of high quality and uniform quality can be obtained.

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

Example 1 A styrene-acrylic acid-butyl acrylate (ratio 45:30:25) copolymer was pulverized using a zigzag classifier manufactured by Alpime to give a uniform diameter of 0.5 to 40μ.
A heat-fusible fine powder was obtained. This fine powder was applied to the surface 2 of a known photosensitive printing plate (Sakura PS version SLP, 0.3 mm thick) that was continuously traveling at a constant speed of 10 m per minute using a powder feeder, per 1 m ² of the printing plate surface. After uniformly dispersing and adhering it to a weight of 0.05 g, it was conveyed by passing between a heating roll 4 and a pressure roll 5. At this time, the heating roll 4 is a normal heating roll whose metal surface is impregnated with Teflon to form a film with a thickness of about 0.1 mm. At the same time, the surface temperature of both ends of the heating roll (the part where both edge portions 2A, 2A of the printing plate surface contact) is lower than the temperature of the center part. Cold air was blown to lower the temperature by 5°C. Further, the contact pressure between the heating roll 4 and the pressure roll 5 was set to 3 kg per 1 cm of the width of the photosensitive printing plate.

The photosensitive printing plate obtained by the method of the present invention has heat-fusible fine powder uniformly heat-fused to the surface of the central portion 2B and both edge portions 2A, 2A, and has the above-mentioned formulation of the present invention. The time required for vacuum adhesion during contact baking was 2 minutes and 20 seconds for the photosensitive printing plate before applying the process, whereas the photosensitive printing plate prepared by the method of the present invention required only 1 minute and 20 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 model manufactured 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) due to the heat-fusible fine powder being fused onto the surface of the photosensitive printing plate.

Next, in Example 1 of the present invention, the same recipe as above was used except that the amount of heat-fusible fine powder uniformly dispersed and adhered to the surface of the printing plate was changed to 0.6 g and 0.004 g per 1 m ² . If the amount is 0.6g per ^1m2 , the reproducibility of small halftone dots will deteriorate, ^and
In the case of the amount of 0.004 g, it was recognized that the improvement in vacuum adhesion was insufficient.

Next, in Example 1 of the present invention described above, except that the heat-fusible fine powder to be uniformly dispersed and adhered to the surface of the printing plate had a directional diameter larger than 40 μm and smaller than 0.5 μm. When the same prescription was applied, the reproducibility of small halftone dots deteriorated for samples using fine powder with a diameter larger than 40μ, and the diameter
It was observed that the improvement in vacuum adhesion was insufficient for the sample using fine powder of less than 0.5μ.

In addition, in the above-mentioned Example 1 of the present invention, without using cold air for cooling the heating roll, the surface temperature of the center part of the heating roll is 180°C, which is the same as above, and the surface temperature of both ends of the heating roll is 180°C, which is the same as above. from the temperature of
When the same recipe as above was used except that heating was carried out at a temperature 20 to 30 degrees Celsius higher, an adverse effect was observed on the printing characteristics of both edge portions of the resulting photosensitive printing plate. Also,
Conversely, in Example 1 above, when cold air was blown so that the surface temperature of both ends of the heating roll was 21°C lower than the temperature of the center, fusion at both ends of the photosensitive printing plate occurred. Defectiveness was recognized.

Example 2 Known photosensitive printing plate (Sakura PS plate SLP, 0.24 mm
thickness) at a constant speed of 10 m per minute,
A preheating roll (the roll numbered 7 in the figure was used as a heated preheating roll) was brought into contact with the back side 3 of this printing plate to preheat the printing plate surface temperature to 80°C, and then the plate was used in Example 1. The same amount of heat-fusible fine powder as in Example 1 was uniformly dispersed and adhered, and then cold air was blown from the back side of this printing plate to bring the surface temperature of both edge portions 2A, 2A of the printing plate to 75°C. It was cooled until it was. Next, the heating roll 4 and pressure roll 5 used in Example 1 (contact pressure per 1 cm width of printing plate)
It is set to 1.2Kg. ), and furthermore, the contact length of the printing plate surface with the heating roll 4 is
The printing plate was passed through a roll 6 to a thickness of 70 mm, heated to a surface temperature of 90° C., and transported to obtain a photosensitive printing plate according to the method of the present invention.

The obtained photosensitive printing plate had a vacuum adhesion time of 2 minutes and 30 seconds (based on the same contact baking method as in Example 1) during contact baking of the photosensitive printing plate before applying the above-mentioned formulation of the present invention. Whereas it was hot, it only took 1 minute and 30 seconds.

Further, the obtained photosensitive printing plate was subjected to the same exposure and development as in Example 1, and the same good results as in Example 1 were obtained.

Furthermore, in Example 2, as in Example 1, the particle size and adhesion amount of the heat-fusible fine powder and the heating temperature of both edge portions of the printing plate were changed.
Results similar to those in Example 1 were obtained.

[Brief explanation of the drawing]

The figure is a schematic diagram of the manufacturing process in a typical example showing the method for manufacturing a photosensitive printing plate of the present invention. In the figure, 1 is a photosensitive printing plate, 2 and 3 are front and back surfaces thereof, 2A and 2A are both edge parts, 2B is a center part, and 4 is a heating roll.

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 When the heat-fusible fine powder is thermally fused to the surface of the photosensitive printing plate by bringing it into contact with a heating roll having a surface with good mold releasability, both edge portions of the surface of the photosensitive printing plate are brought into contact with the photosensitive printing plate. 1. A method for producing a photosensitive printing plate, which comprises heating at a temperature lower than the heating temperature of the central part of the surface of the photosensitive printing plate.