JPH08257979A - Method for producing cut photosensitive planographic plate and method for producing stack of cut metallic thin plate - Google Patents

Abstract

PURPOSE: To reduce the rate at which inferior product quality arises due to dull cutting blades by stacking a plurality of photosensitive planographic plates having a photosensitive layer formed over their metal support, and cutting the stacked photosensitive planographic plates with a cutting blade having a specific coefficient of friction. CONSTITUTION: When a plurality of photosensitive planographic plates 7 having a metal support and stacked are placed on a stand 5, the plates 7 stacked are made to abut to a back stopper 3 and aligned, and a cutting blade 1 is lowered in the vertical direction relative to the stand 5 by a cutting-blade drive to cut all the planographic plates 7 at a time. The plates 7 stacked are held from above by a stopper 2 that can be moved vertically via a spring 23, to ensure a stable cutting operation. In such a cutting method, the flank 12 of the cutting blade 1 is made to have a coefficient of friction of 0.3 or less, and for that purpose the flank 11 of the cutting blade 1 facing a product 71 is coated with wax, fatty-acid wax, or the like as necessary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a cut photosensitive lithographic printing plate and a method for producing a cut metal thin plate aggregate.

[0002]

2. Description of the Related Art Conventionally, as a cutting blade for cutting a thin metal plate assembly, a blade having a coefficient of friction with an object to be cut of 0.4 or more has been used without applying a lubricant.

[0003]

However, with the conventional cutting blade, the cutting edge of the cut photosensitive lithographic printing plate or the cut metal thin plate often suffers from poor sharpness such as burrs. Therefore, the cutting blade had to be frequently ground.

Then, when the cause of this is investigated, it is considered that the cause is explained below with reference to FIG. A metal thin plate assembly 7 such as a photosensitive lithographic printing plate which is a cut object is placed on the mounting table 5 and the back stopper 3
While being held fixedly by being held by the stopper 2, the metal thin plate stack 7 such as the photosensitive lithographic printing plate is lowered by the cutting blade 1 and cut. However, the conventional cutting blade 1
In this case, the frictional resistance with the object to be cut is large, and therefore, a large frictional force is generated between the cutting blade 1 and the metal thin plate assembly 7 such as the photosensitive lithographic printing plate which is the object to be cut. Since the adhesion 14 of metal powder or the like from the accumulated body occurs, the cut edge of the product causes poor sharpness such as scratches 74 and burrs 75, and once the adhesion occurs, the surface of the cutting blade 11 It is thought that it is difficult to remove because it is rough.

An object of the present invention is to reduce the occurrence of poor cutting quality of a cutting blade, and to reduce the occurrence of poor product quality due to poor cutting quality of a cutting blade.

[0006]

The above object of the present invention can be achieved by the constitution described below.

[Claim 1] [A plurality of photosensitive lithographic printing plates having a photosensitive layer formed on a metal support are accumulated, and are accumulated by a cutting blade having a friction coefficient of 0.3 or less on the back surface of the edge of the metal support. A method for producing a cut photosensitive lithographic printing plate, which comprises cutting the obtained photosensitive lithographic printing plate. [Claim 2] [Cutting metal characterized by accumulating a plurality of thin metal plates, and cutting the stacked thin metal plates with a cutting blade having a friction coefficient of the back surface of the cutting edge with the thin metal plates of 0.3 or less. Method for producing thin plate assembly. [Item 3] [A plurality of photosensitive lithographic printing plates having a photosensitive layer formed on a metal support are accumulated, and a water-soluble lubricant containing, as a main component, at least one of fatty acid soap or fatty acid ester is provided on the back surface of the cutting edge. A method for producing a cut photosensitive lithographic printing plate, comprising cutting the photosensitive lithographic printing plates accumulated by the applied cutting blade into a predetermined shape. [Item 4] "Cutting the metal thin plates accumulated by a cutting blade in which a plurality of metal thin plates are accumulated and a water-soluble lubricant containing at least one of fatty acid soap and fatty acid ester as a main component is applied to the back surface of the cutting edge. A method for producing a cut metal sheet assembly, comprising: The present invention is suitable for a photosensitive lithographic printing plate whose support is a metal. The support for the photosensitive lithographic printing plate is preferably an aluminum plate, a zinc plate, or a stainless plate, and is preferably subjected to hydrophilic treatment such as surface oxidation treatment.

The metal thin plate stack is a stack of many metal thin plates. The thin metal plate stack may be a stack of a large number of thin metal plates, and a stacking plate such as a ball may be arranged above and below the metal thin plate, or a sandwiching sheet such as a sandwich paper may be arranged between the thin metal plates. It may be one. Further, the metal thin plate may be a thin plate made of only metal, or a photosensitive lithographic printing plate having metal as a support. The metal may be a hard metal such as steel or stainless steel, but the present invention is suitable for a soft metal such as aluminum or zinc.

In order to firmly hold the thin metal plate assembly or the integrated photosensitive lithographic printing plate, not only a method of holding the thin plate assembly by a grip or the like but also the thin metal plate integrated body or the integrated photosensitive lithographic printing plate on a mounting table. Place the plate on it and hold it with the side stoppers from the surfaces that face each other, with the stopper from the top, with the back stopper from the surface that faces the cutting blade, and with a combination of some of these methods. Is mentioned. In addition, after cutting the thin metal plate stack or the integrated photosensitive lithographic printing plate, the fixed holding of the thin metal plate stack or the stacked photosensitive lithographic printing plate may be released, and then the cutting blade may be returned. This is preferable because it is possible to prevent scratches that occur when the blade is returned and burr on the upper side of the cut end of the product. To release the fixed holding of the thin metal plate aggregate or the accumulated photosensitive lithographic printing plate, these grips,
Even if you do not separate the side stopper, stopper, and back stopper from the thin metal plate assembly or the photosensitive lithographic printing plate
It also includes the fact that the stress generated between the metal thin plate aggregate and the accumulated photosensitive lithographic printing plate between the sheet and the cutting blade is substantially released.

The cutting blade preferably has a flank on the product side, and the inclination angle of the flank is tan θ ≧ 0.0.
It is preferable that 05 (particularly tan θ ≧ 0.010). Further, the cutting blade is preferably made of high speed steel.
The surface of the cutting blade is preferably mirror-finished by buffing, diamond fine particle polishing, or the like.

The effect of the present invention can be obtained by setting the friction coefficient of the back surface of the cutting edge with the metal support or the thin metal plate to 0.3 or less, but it is more preferable to set it to 0.2 or less.
It is more preferable to set it to 1 or less. The friction coefficient of the back of the cutting edge with the metal support or thin metal plate is the coefficient of dynamic friction.While pressing a small piece of the same material as the metal support or thin metal plate against the back of the cutting edge with a predetermined pressure, It can be obtained by moving on the back. Further, the friction coefficient "rear surface of the cutting edge" of the back surface of the cutting edge with the metal support or the thin metal plate referred to in the present application corresponds to the thickness of the photosensitive lithographic printing plate or the thin metal plate assembly accumulated from the cutting edge. , The back of the cutting edge above it does not matter.

In order to reduce the friction coefficient of the back surface of the cutting edge of the metal support or the thin metal plate to 0.3 or less, the cutting edge of the cutting edge is treated with a friction reducing coating such as Teflon coating. Method, a method of making the back surface of the cutting edge of the cutting blade a surface treatment such as oxidation treatment or sulfurization, and a method of applying a lubricant to the back surface of the cutting edge of each cutting edge at appropriate intervals. Is mentioned.

The lubricant used in the present invention includes inorganic fine powders such as molybdenum disulfide, boron nitride and zinc oxide, resin fine powders such as polyfluorinated ethylene resin fine powders, and waxes such as carnauba wax. ), Lubricating oils such as grease and silicone oil, and organic compound lubricants such as perfluoro fatty acid, perfluoro fatty acid ester, fluoride ester such as perfluoro alkyl sulfate ester, and fatty acid ester. Further, water-soluble lubricants such as beef tallow fatty acid, fatty acid soap and fatty acid ester are also used. Among these, in the method of applying the lubricant to the back surface of the cutting edge of the cutting knife at appropriate intervals, wax (wax) is preferable because the cost is low and the application frequency is low. Also, there is no load for the lubricating oil to be applied for each cutting,
It is preferable because the cost is low, it is possible to prevent the sharpness of the cutting blade from being generated for a long period of time, and the occurrence of defective product quality can be reduced. Further, the lubricating oil is preferably liquid at the cutting environmental temperature.

Further, when cutting is performed, a small amount of the lubricant applied to the cutting blade adheres to the metal plate. When the metal plate to be cut has the photosensitive layer formed, if the development process is performed as it is, the lubricant is mixed in the processing liquid. In such a case, if the lubricant is water-soluble, there is no particular problem, but if it is water-insoluble or oil-based, the quality will be seriously adversely affected. That is, if a lubricating oil is used to cut the metal plate on which the photosensitive layer is formed, the lubricating oil remains on the metal plate, which causes ink to lie on the oil. The resulting image will become extremely dirty. In addition, when printing on a thin metal plate, it is difficult to remove the lubricating oil and the print quality is likely to be adversely affected. Therefore, it is preferable to use a water-soluble lubricant rather than a lubricating oil (especially when the metal plate to be cut has a photosensitive layer formed thereon), and even in the case of a water-soluble lubricant, adhesion does not occur. Most preferably, a type of fatty acid soap or fatty acid ester is used.

[0015]

The examples show one example of the specific examples of the present invention, and do not limit the present invention in any way. In addition, although there is a assertive description, it is preferable as a specific example of the present invention and does not limit the present invention. For example, the present invention may be used to cut printed chin-free steel for Patrone body plates for silver halide photographic films.

Embodiment 1 FIG. 1 is a schematic sectional view of a cutting device of this embodiment. The cutting apparatus of this embodiment includes a mounting table 5 on which a plurality of photosensitive lithographic printing plates 7 are stacked and mounted, and a plurality of photosensitive lithographic printing plates 7 that are stacked.
A back stopper 3 for aligning, a cutting blade 1 for cutting the photosensitive lithographic printing plate 7, and a photosensitive lithographic printing plate 7 held from above when the cutting blade 1 cuts the photosensitive lithographic printing plate 7. And a stopper 2.

The upper surface of the mounting table 5 is a flat surface and holds the photosensitive lithographic printing plate 7 horizontally without distortion. Further, an underlay 4 is provided at a portion of the mounting table 5 which is in contact with the cutting blade 1, so that the cutting blade 1 does not spill.

The clearance surface 11 of the cutting blade 1 on the product 71 side has a clearance angle of tan θ = 0.013 with respect to the vertical. Further, the cutting edge surface 12 of the cutting blade 1 on the loss 72 side has an angle of 30 ° with respect to the flank surface 11 of the cutting blade 1 on the product 71 side. The cutting blade 1 is attached to a base metal of a cutting blade driving device (not shown), and moves vertically to the mounting table 5 to cut the photosensitive lithographic printing plate 7. The cutting blade is high speed steel.

The back stopper 3 holds the end surface of the photosensitive lithographic printing plate 7 parallel to the cutting surface of the photosensitive lithographic printing plate 7 with its smooth vertical surface 31, thereby aligning the photosensitive lithographic printing plates 7 integrated. . The back stopper 3 is movable on the mounting table 5 in a direction perpendicular to the smooth vertical surface 31.

The stopper 2 holds the photosensitive lithographic printing plate 7 from above with its smooth lower surface 21. Further, the stopper 2 is movable up and down via a spring 23 which is an elastic member, and when the cutting blade 1 cuts the photosensitive lithographic printing plate 7, the stopper 2 holds the photosensitive lithographic printing plate 7 from above. It is held down by 23.

In order to collect the photosensitive lithographic printing plates 7, the balls are placed on the mounting table 5 before the photosensitive lithographic printing plates 7 are stacked, and the photosensitive lithographic printing plates 7 are placed one by one. The balls are stacked in parallel while sandwiching the sandwich paper, and the balls are placed on the stack, and the balls are applied to the upper and lower sides of the stacked photosensitive lithographic printing plates 7. As a result, in the subsequent step, by cutting the ball together with the ball, it is possible to save the trouble of separately cutting and positioning the ball and applying the photosensitive lithographic printing plate 7 accumulated.

In this embodiment, wax is applied to the flank 11 of the cutting blade 1 on the side of the product 71 at an appropriate interval. FIG. 3 is a diagram showing the behavior after the wax is applied to the flank 11 of the cutting blade 1 on the product 71 side.
It is the figure which showed extremely large the minute unevenness of the flank 11 on the product 71 side of the cutting blade 1. When wax is applied to the flank 11 on the product 71 side of the cutting blade 1, it is applied to the entire flank 11 on the product 71 side of the cutting blade 1 as shown in FIG. When the coated cutting blade 1 cuts the photosensitive lithographic printing plate 7 as shown in B, excess wax is transferred from the cutting blade 1 onto the ball placed on the photosensitive lithographic printing plate 7. Therefore, a large amount of wax does not affect the photosensitive lithographic printing plate 7 by being deposited on the photosensitive lithographic printing plate 7. And
After the cutting, the wax remains in the recess of the flank 11 on the product 71 side of the cutting blade 1, and the wax is supplied from each recess, whereby the flank 1 on the product 71 side of the cutting blade 1 is cut.
It is considered that the friction of 1 is reduced.

The sandwich paper used here is a paper in which polyethylene is impregnated, the ball is cardboard, and the number of photosensitive lithographic printing plates accumulated is 25.
The number of sheets is preferably 100 or more and 100 or less. The photosensitive lithographic printing plate 7 was anodized after an aluminum plate having a thickness of about 0.2 to 0.3 mm was grained and then 1.0
It is preferable that the photosensitive resin layer is provided by coating on an aluminum plate on which an oxide film of about 3.0 g / m ² is formed. The coating amount of the photosensitive resin layer provided on the aluminum support of the photosensitive lithographic printing plate 7 after drying is 1.5 to
It is about 3.0 g / m ² .

Embodiments 2 and 3 In Embodiment 1, wax is applied to the flank 11 of the cutting blade 1 on the side of the product 71 at appropriate intervals, whereas the product 71 has already been applied.
In the second embodiment, the cutting blade 1 whose side flank 11 is oxidized is used. In addition, the flank 11 on the side of the product 71 has already been reached.
In the third embodiment, the cutting blade 1 which is Teflon coated is used.

Example 4 In Example 1, wax is applied to the flank 11 of the cutting blade 1 on the side of the product 71 at appropriate intervals, whereas the flank 11 on the side of the product 71 of the cutting blade 1 is cut for each cutting. In this embodiment, lubricating oil is applied. Hereinafter, the difference from the first embodiment and the operation thereof will be described based on FIG.

The difference from the apparatus of the first embodiment is that a sponge 22 is provided as a soft impregnating material for permeating lubricating oil on the cutting blade 1 side of the stopper 2. Before cutting, the tip 13 of the cutting blade 1 is at a position higher than the lower end of the sponge 22, and the sponge 22 hits the cutting blade 1. When the device is operated, the sponge 22
Infiltrate the lubricating oil into. Then, before the cutting blade 1 descends, the stopper 2 escapes from the cutting blade 1, the back surface 11 of the cutting edge of the cutting blade 1 and the sponge 22 separate, and then the cutting blade 1 is lowered to the tip 13 of the cutting blade 1. Height and sponge 2
When the height of the lower end 24 of the cutting edge 2 coincides with that of the cutting edge 1, the stopper 2 is pressed against the cutting edge 1, and the sponge 22 moves the product 7 of the cutting edge 1.
It hits the flank 11 on the first side. Then, lubricating oil is applied from the tip of the cutting blade 1. As a result, the sponge 22 is not damaged at the tip of the cutting blade 1. After that, the sponge 22 hits the cutting blade 1.

The cutting procedure will be described below. First, after placing the photosensitive lithographic printing plate 7 on the mounting table 5 in the same manner as in Example 1, the stopper 2 and the cutting blade 1 are simultaneously lowered as shown in FIG. Then, the stopper 2 and the cutting blade 1 are further lowered, but as shown in FIG. 4B, the stopper 2 holds the photosensitive lithographic printing plate 7 only by contracting the spring 23. Further, the end portion of the photosensitive lithographic printing plate 7 opposite to the cutting blade 1 is suppressed by the back stopper 3. Therefore, the photosensitive lithographic printing plate 7 is fixedly held.
On the other hand, the flank 11 of the cutting blade 1 descends while hitting the sponge 22, so that the lubricating oil is applied in order, and the cutting blade 1 cuts the photosensitive planographic printing plates 7 including the balls. , Descend until it hits the underlayment 4. Here, the excess lubricating oil is prevented from being applied to the cutting blade 1, but since the cutting blade 1 first comes into contact with the ball, it is placed on the photosensitive lithographic printing plate 7 from the cutting blade 1. The lubricating oil is absorbed by the present ball and does not adversely affect the photosensitive lithographic printing plate 7. After that, the cutting blade 1 and the stopper 2 rise.

Examples 5, 6 and 7 In Example 4, the lubricating oil is applied from the sponge 22 to the cutting blade 1, whereas in Example 5 the tallow fatty acid is used alone, and in Example 6
Is a fatty acid soap alone, and Example 7 is the same as Example 4 except that a fatty acid ester is applied alone.

Embodiment 8 This embodiment is an example in which the operation of the apparatus of Embodiments 1 to 7 is modified. FIG. 5 is an operation explanatory view of the cutting device of the present embodiment.
The operation of the cutting device of this embodiment will be described based on FIG.

In step S1, the photosensitive lithographic printing plates 7 are collected.
This ball is placed on the mounting table 5 before the photosensitive lithographic printing plate 7 is accumulated.
The photosensitive lithographic printing plates 7 are placed one on top of the other, and are stacked one by one with the paper sandwiched between them. Then apply the ball. As a result, in the subsequent step, by cutting the ball together with the ball, it is possible to save the trouble of separately cutting and positioning the ball and applying the photosensitive lithographic printing plate 7 accumulated. S2 indicates a state in which the photosensitive lithographic printing plates 7 are integrated.

At S3, the stopper 2 and the cutting blade 1 are simultaneously lowered. Then, in S4, the stopper 2 and the cutting blade 1 are further lowered, but the stopper 2 holds the photosensitive lithographic printing plate 7 only by contracting the spring 23. Further, the end portion of the photosensitive lithographic printing plate 7 opposite to the cutting blade 1 is suppressed by the back stopper 3. Therefore, the photosensitive lithographic printing plate 7 is fixedly held. On the other hand, the cutting blade 1 descends until it hits the underlay 4 while cutting the photosensitive lithographic printing plates 7 including the balls.

Unlike in Examples 1 to 7, in step S5, the stopper 2 is raised before the cutting blade 1 is raised, and is separated from the accumulated photosensitive lithographic printing plate 7, and the back stopper 3 is also horizontal. It moves and separates from the accumulated photosensitive lithographic printing plate 7. Therefore, the fixed holding of the integrated photosensitive lithographic printing plate 7 is released. Then, in S6, the stopper 2 and the back stopper 3 are separated from the accumulated photosensitive lithographic printing plate 7, and the fixed holding of the accumulated photosensitive lithographic printing plate 7 is released, and then the cutting blade 1 is moved up. . As a result, scratches and burrs do not occur on the upper side of the cut of the product.

In step S7, the cut photosensitive lithographic printing plate 71 and the cut loss-side photosensitive lithographic printing plate 72 are taken out from the mounting table 5. The cut photosensitive lithographic printing plate 71 taken out
Will be shipped in cardboard packaging in a later process. In addition, the photosensitive lithographic printing plate 72 on the loss side is further cut and commercialized or discarded.

Modifications In the above-described Examples 1 to 8, the stopper 2 is movable up and down via the spring 23 which is an elastic member, and when the cutting blade 1 cuts the photosensitive lithographic printing plate 7, it is photosensitive. Although the stopper 2 is held down so as to hold the planographic printing plate 7 from above, the stopper 2 can be moved up and down by a hydraulic cylinder, and the stopper 2 is lowered by the hydraulic cylinder before the cutting blade 1 is lowered. When the cutting blade 1 cuts the photosensitive lithographic printing plate 7, the stopper 2 may be held down by a hydraulic cylinder so as to hold the photosensitive lithographic printing plate 7 from above.

Experiment In order to confirm the effect of the present invention, the following acceleration experiment was conducted.

In each of the above examples, a cutting blade having a length corresponding to the actual width of the photosensitive lithographic printing plate is used. However, a cutting blade device having a length of about 10 cm was prepared for the experiment, and the cutting was performed. The friction coefficient of the back surface (flanking surface 11) of the blade edge of the blade was determined, and the sandwiched paper between the photosensitive lithographic printing plates 7 sandwiched in each example was not sandwiched, but the photosensitive lithographic printing plate 7 having a width of about 7 to 8 cm. After cutting 50 sheets, the flank 11 of the cutting blade 1 was continuously checked, and it was observed how many times the cutting was performed to confirm the adhesion of the flank 11 of the cutting blade 1. This experiment was done several times. Since this experiment is an acceleration experiment that does not pinch a pinch paper, 1
If adhesion is not observed up to about 0 times, it is a significant improvement compared to the conventional case.

When nothing is applied or processed as in the conventional case,
The coefficient of friction was 0.45, and poor cutting performance was observed after cutting three times. When carnauba wax was used as the wax in Example 1, the coefficient of friction was 0.10.
No poor sharpness was observed until about 5 times of cutting. In the case of Examples 2 and 3, the friction coefficient was 0.11 to 0.20, and no poor sharpness was observed until about 10 times of cutting. When silicone oil was used as the lubricating oil in Example 4, the friction coefficient was 0.01 to 0.05, and no poor sharpness was observed even after cutting 50 times. When a water-soluble lubricant containing beef tallow fatty acid as a main component was used as Example 5, the coefficient of friction was 0.05 to 0.10. No poor sharpness was observed until about 5 times of cutting. When a water-soluble lubricant containing fatty acid soap as a main component was used as Example 6, the coefficient of friction was 0.05 to 0.10, and poor sharpness was not observed until about 10 times of cutting. When a water-soluble lubricant containing a fatty acid ester as a main component was used in Example 7, the coefficient of friction was 0.01 to 0.05, and no poor sharpness was observed even after cutting 50 times. In addition, when the above-mentioned seven experiments were performed with the cutting blade of Example 3, the friction coefficient did not change from each case, but no poor sharpness was observed even after cutting 50 times.

In particular, when a metal plate having a photosensitive layer formed thereon is cut and then subjected to a development process, an image formation is hindered by a lubricant or lubricating oil.
Carnauba wax and silicone oil were problems, but there was no problem in the other Examples. Next, the results are summarized in the table below. As is clear from the table, the number of cuts until the occurrence of poor sharpness,
From the viewpoint of the influence on the product, it is understood that it is most preferable to use the water-soluble lubricant, especially the fatty acid ester. The results are summarized in the table below.

[0039]

[Table 1]

The same experiment was performed in the modified example, but the result was the same. Further, if the poor cutting quality does not occur for a long period of time, not only the occurrence of the deterioration of the product quality due to the poor cutting quality of the cutting blade is reduced, but also the number of times of polishing the cutting blade with the deteriorated cutting ability can be reduced, and the productivity is improved. be able to.

[0041]

According to the present invention, the occurrence of poor sharpness of the cutting blade is reduced. Further, it is possible to reduce the occurrence of deterioration of product quality due to poor cutting quality of the cutting blade.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a cutting device.

FIG. 2 is a diagram showing a conventional cutting blade having a poor sharpness due to adhesion and a product quality defect caused thereby.

FIG. 3 is a diagram showing an example of applying wax according to the first embodiment.

FIG. 4 is a diagram showing an example of oil application in Example 4;

FIG. 5 is an explanatory diagram illustrating an operation of the fifth embodiment.

[Explanation of symbols]

 1 Cutting Blade 2 Stopper 3 Back Stopper 4 Underlay 5 Mounting Table 6 Wax 7 Photosensitive Planographic Printing Plate 11 Flank Surface of Cutting Blade 1 on Product 71 Side 12 Cutting Edge 1 Loss Edge Side of Cutting Edge 13 Cutting Edge 1 Tip 21 Lower surface of stopper (holding surface) 22 Sponge 23 Spring 24 Lower end of sponge 31 Smooth vertical surface of back stopper 3 71 Product side of photosensitive lithographic printing plate 72 Loss side of photosensitive lithographic printing plate

Claims (4)

[Claims] 1. A plurality of photosensitive lithographic printing plates, each having a photosensitive layer formed on a metal support, are stacked, and are stacked by a cutting blade having a coefficient of friction of 0.3 or less on a back surface of a cutting edge with the metal support. A method for producing a cut photosensitive lithographic printing plate, which comprises cutting the photosensitive lithographic printing plate. 2. A cut metal thin plate, wherein a plurality of metal thin plates are accumulated, and the metal thin plates are cut by a cutting blade having a friction coefficient of the back surface of the cutting edge with the metal thin plate of 0.3 or less. Manufacturing method of aggregate. 3. A plurality of photosensitive lithographic printing plates having a photosensitive layer formed on a metal support are accumulated, and a water-soluble lubricant containing at least one of fatty acid soap and fatty acid ester as a main component is coated on the back surface of the cutting edge. A method for producing a cut photosensitive lithographic printing plate, which comprises cutting the photosensitive lithographic printing plates accumulated by a cutting blade into a predetermined shape. 4. A plurality of metal thin plates are accumulated, and the metal thin plates are cut by a cutting blade coated with a water-soluble lubricant containing at least one of fatty acid soap and fatty acid ester as a main component on the back surface of the cutting edge. A method for producing a cut metal sheet assembly, comprising: