JP2001205950A - Apparatus and method for cutting photopolymerizable lithographic printing plate, and photopolymerizable lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an apparatus and a method for cutting a photopolymerizable lithographic printing plate without generating a fog by cutting. SOLUTION: A contact part 50 of an upper blade 22 for constituting a slitter 10 is obliquely contacted with an upper surface 12A of a web 12 at a predetermined contact angle θ1 (30 deg. to 70 deg.). When upper blades 52, 58 hold the web 12 and cut the web 12 by the blade 22, and a lower blade 58 regulated so that an engaging amount D at the cutting time becomes 500% or less of a thickness T of the web 12, an excess pressure is not operated from the part 38 in a wide region of a photosensitive layer 54 of the photopolymerizable lithographic printing plate 30, and hence a pressure fog is not generated. Even in the case of developing by using the plate 30, a so-called film residue is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photopolymerizable lithographic printing plate cutting apparatus, a photopolymerizable lithographic printing plate cutting method, and a photopolymerizable lithographic printing plate.

[0002]

2. Description of the Related Art FIGS. 7 and 8 show a slitter 150 which is an example of a conventional lithographic printing plate cutting apparatus (see Japanese Patent Application Laid-Open No. 2-124293).

In the slitter 150, the lithographic printing plate 15
A cutting blade 158 composed of an upper blade 154 and a lower blade 156 is provided in the vicinity of both ends in the width direction. The upper blade 154 has a contact portion 162 that is inclined with respect to the photosensitive layer (upper surface) of the lithographic printing plate 152 and has a sharp end. On the other hand, the outer peripheral surface of the lower blade 156 is
2 and parallel. When the upper blade 154 and the lower blade 156 rotate, the lithographic printing plate 152 is conveyed while the lower blade 156 is being conveyed.
And cut (cut) at the tip of the contact portion 162 of the upper blade 154. And the part inside cutting blade 158 is made into a product.

In recent years, a photopolymerizable lithographic printing plate has been used in order to obtain a clear image by exposing at a low exposure amount using a laser exposure apparatus and preventing a reduction in resolution due to a scattering phenomenon such as flare. There is.

A great deal of research has been conducted on photopolymerizable lithographic printing plates. In particular, recently, a laser printing plate utilizing a high-sensitivity photopolymerization initiation system capable of responding to a visible laser such as an argon laser has been developed. I have. Many of these photopolymerizable lithographic printing plate precursors include a compound containing an ethylenic double bond capable of addition polymerization on an aluminum plate as a support, a photopolymerization initiator, an organic polymer binder optionally used, A photopolymerizable composition layer comprising a polymerization inhibitor and the like was provided, and an overcoat layer containing polyvinyl alcohol and / or a polyvinyl alcohol copolymer as a main component was further provided thereon to block oxygen that inhibits polymerization. Things. In these photopolymerizable lithographic printing original plates, a relief image is obtained by imagewise exposing a desired image to polymerize and cure an exposed portion and removing an unexposed portion with a developing solution. The unexposed part exposes the grained aluminum support, and since the surface is hydrophilic, retains water and repels oil-based ink. Since the portion (image portion) cured by exposure is lipophilic, it repels water and accepts ink.

A cutting device and a cutting method for cutting such a photopolymerizable lithographic printing plate into a desired size are not particularly proposed. For example, cutting is performed using a slitter 150 shown in FIGS. 7 and 8. In this case, since the contact portion 162 of the upper blade 154 comes into contact with the photosensitive layer of the portion to be a product at a small contact angle (in other words, at an angle close to parallel), the contact portion 162 of the upper blade 154 has a large area of the cutting edge of the portion to be a product. Shear stress acts. In general, a photopolymerizable lithographic printing plate has a very high sensitivity, and so-called pressure fogging occurs when pressure (shear stress) acts on or deforms the photosensitive layer as well as slight light. Therefore, when the above-mentioned shear stress acts on the photosensitive layer in the portion to be a product,
In the vicinity of the cut edge of the product (that is, the portion where the contact portion 162 is in contact), pressure fogging occurs due to the pressure received from the contact portion 162 and the deformation generated during cutting, and a so-called residual film is generated after development.

[0007]

SUMMARY OF THE INVENTION In view of the above facts, the present invention provides a photopolymerizable lithographic printing plate free from fogging due to cutting, and a photopolymerizable lithographic printing plate for producing such a photopolymerizable lithographic printing plate. It is an object to obtain a lithographic printing plate cutting device and a photopolymerizable lithographic printing plate cutting method.

[0008]

According to the present invention, a photopolymerizable lithographic printing plate is cut at a predetermined position by sandwiching the photopolymerizable lithographic printing plate in at least one pair of cutting blades in the thickness direction. An apparatus, wherein a contact portion between a photosensitive layer of a photosensitive layer side cutting blade located on a photosensitive layer side of the photopolymerizable lithographic printing plate among the blades constituting the pair of cutting blades is a photopolymerizable lithographic printing plate. On the other hand, the photosensitive layer side cutting blade is arranged such that the contact is made at an angle of 30 ° or more and 70 ° or less and the bite amount at the time of cutting is 70% or more and 500% or less of the plate thickness of the photopolymerizable lithographic printing plate. It is characterized by the following.

In this photopolymerizable lithographic printing plate cutting apparatus, of the blades constituting the pair of cutting blades, the photosensitive layer side cutting blade has a contact portion with the photosensitive layer that is 30 times smaller than the photopolymerizable lithographic printing plate. °
Contact at least 70 °. For this reason, compared with the conventional general lithographic printing plate cutting device, the shear stress is more concentrated near the cutting edge, and the shear stress does not act on a wide area.

[0010] Further, since the biting amount at the time of cutting is set to be 70% or more and 500% or less of the plate thickness of the photopolymerizable lithographic printing plate, the photopolymerizable lithographic printing plate may be pressed more than necessary at the time of cutting. It can be cut without fail.

As a result, the photosensitive layer of the photopolymerizable lithographic printing plate cut using the photopolymerizable lithographic printing plate cutting apparatus is not subjected to pressure or deformed, and is not so-called. No pressure fogging occurs. For this reason, no residual film is generated during development.

According to a second aspect of the present invention, there is provided a photopolymerizable lithographic printing plate cutting method for cutting a photopolymerizable lithographic printing plate at a predetermined position with at least a pair of cutting blades, wherein the pair of cutting blades is constituted. While contacting the contact portion with the photosensitive layer of the photosensitive layer side cutting blade of the photopolymerizable lithographic printing plate is 30 ° or more and 70 ° or less with respect to the photopolymerizable lithographic printing plate, The method is characterized in that the photopolymerizable lithographic printing plate is sandwiched in the plate thickness direction and cut so that the bite amount at the time of cutting is 70% or more and 500% or less of the plate thickness of the photopolymerizable lithographic printing plate.

When the photopolymerizable lithographic printing plate is cut by the photopolymerizable lithographic printing plate cutting method, the photosensitive layer side of the blade constituting the pair of cutting blades, which is located on the photosensitive layer side of the photopolymerizable lithographic printing plate. The contact portion of the cutting blade with the photosensitive layer contacts the photopolymerizable lithographic printing plate at an angle of 30 ° or more and 70 ° or less. For this reason, compared with the conventional general planographic printing plate cutting method,
The shear stress is more concentrated near the cutting edge, and the shear stress does not act on a wide area.

Further, in this photopolymerizable lithographic printing plate cutting method, the cutting is performed so that the bite amount at the time of cutting is 70% to 500% of the plate thickness of the photopolymerizable lithographic printing plate. The photopolymerizable lithographic printing plate can be cut without being pressed more than necessary.

As a result, the photosensitive layer of the photopolymerizable lithographic printing plate cut by the method for cutting a photopolymerizable lithographic printing plate is free from pressure acting or deforming, and so-called pressure fogging. Does not occur. For this reason, no residual film is generated during development.

According to the third aspect of the present invention, there is provided a photopolymerizable lithographic printing plate which is cut at a predetermined position by at least a pair of cutting blades, wherein the photopolymerizable lithographic plate among the blades constituting the pair of cutting blades. The contact portion of the photosensitive layer side cutting blade, which is located on the photosensitive layer side of the printing plate with the photosensitive layer, is brought into contact with the photopolymerizable lithographic printing plate at an angle of 30 ° or more and 70 ° or less, and the bite amount at the time of cutting is photopolymerized. 70% or more of the plate thickness of the lithographic printing plate 5
It is characterized by being cut while being sandwiched in the thickness direction so as to be not more than 00%.

That is, the pair of cutting blades for cutting the photopolymerizable lithographic printing plate is such that the contact portion of the photosensitive layer side cutting blade located on the photosensitive layer side of the photopolymerizable lithographic printing plate with the photosensitive layer is a photopolymerizable lithographic printing plate. It contacts the printing plate at 30 ° or more and 70 ° or less, and the bite amount at the time of cutting is 70% or more and 500% or less of the plate thickness of the photopolymerizable lithographic printing plate. It is cut at a predetermined position by this cutting blade. Since shear stress concentrates near the cutting edge during cutting and no shear stress acts on a wide area, the photosensitive layer of the photopolymerizable lithographic printing plate is under pressure or deformed. No so-called pressure fogging occurs. For this reason, no residual film is generated during development.

In the present invention, the term "cut" refers to cutting through a photopolymerizable photosensitive printing plate at a predetermined position in a plate thickness direction, for example, a long photopolymerizable photosensitive printing plate. In addition to cutting the web along the width direction, cutting (so-called cutting) such a long web along the longitudinal direction, cutting the web in an oblique direction, and the like are all included.

[0019]

FIG. 1 shows a photopolymerizable lithographic printing plate processing line 9 equipped with a slitter 10 (cutting device) which is a photopolymerizable lithographic printing plate cutting device according to a first embodiment of the present invention.
0 is shown.

An upstream side (upper right side in FIG. 1) of the processing line 90 is provided with a feeder 14 for sequentially unwinding a web wound in a roll. When the elongate web 12 sent from the feeder 14 is curled by the leveler 15 and reaches the feed roller 16, the interleaf paper 18 is stuck and adhered by charging to reach the notcher 20.

The notcher 20 is provided with a punched portion on the web 12, and has an upper blade 22 and a lower blade 24 (see FIG. 2) of the slitter 10.
) Can be moved in the width direction of the web 12 at the punching position. This makes it possible to change the cutting width of the web 12 while continuously cutting the web 12 and the interleaf 18 together. Hereinafter, when simply referred to as “width direction”, it refers to the width direction of the web 12, and “inside” and “outside”.
In this case, the inside and outside in the width direction of the web 12 are respectively referred to.

Cutting waste 8 generated by cutting by slitter 10
6 is sent to a chopper (not shown) and cut into small pieces, and then collected in a collection box 84 by a collection conveyor 82.
The interleaf paper 18 stuck to the cutting waste 86 is suctioned by the suction pipe 23.

In the processing line 90 of this embodiment,
The slitting unit 21 is constituted by the slitter 10 and peripheral members (not shown), and two sets of the cutting unit 21 are prepared. As a result, setup work such as blade replacement can be performed.
The cutting can be performed by the unused cutting unit 21 outside the line, and the line stop time of the processing line 90 can be minimized.

In the web 12 having the predetermined cutting width, the length of the web 12 is detected by the length measuring device 26, and the running cutter 28 cuts the web 12 at the designated timing. A photopolymerizable lithographic printing plate 30 having a size is manufactured.

Next, the photopolymerizable lithographic printing plates 30 are sent to a stacking section 34 by a conveyor 32, and are stacked in a predetermined number to form a stack 31. In the stacking section 34, a protection sheet (generally referred to as a "ball") made of cardboard or the like can be arranged on the upper and lower sides or on one side of the stack 31.

Then, the stack 31 is stacked on the pallet 33 via the transport section 35. After that, it is sent to a storage such as a rack warehouse or a packaging process, and is packaged by a packaging material (tape, interior material, exterior material, etc.). It is also possible to stack on a skid for an automatic plate making machine (flat skid, vertical skid, etc.). In addition, when stacking and packaging these skids, the processing line 90
Alternatively, a stacking device for stacking the stack 31 on the skid may be provided so that the stack 31 is directly stacked on the skid in the processing line 90.

In this way, the photopolymerizable lithographic printing plate 30
Is packaged and shipped, but depending on the packaging form, the slip sheet 18 and other packaging materials may be omitted.

As shown in FIG. 2, the slitter 10 has cutting blades 24 and 26 provided at the center and both sides in the width direction. The central cutting blade 24 is composed of an upper blade 52 located above the web 12 (on the side where the photosensitive layer is applied) and a lower blade 56 located below.

In FIGS. 2 and 3 and FIG. 5 to be described later, for convenience of illustration, the web 12 at the time of cutting (or cutting) is shown.
Shear deformation of the web (the web 1 near the cutting edge or the cutting edge)
2 is larger than the actual case, but the actual amount of deformation is extremely small.

The upper blade 52 is attached to a shaft 78, and rotates at a constant speed so that a portion in contact with the web 12 is in a direction in which the web 12 is conveyed. Also, as can be seen from FIG. 3, the upper blade 52 is formed in a flat and substantially conical shape, and its outer peripheral surface has a predetermined contact angle θ1 with respect to the upper surface of the web 12 (30 ° or more and 70 ° or less). And a contact portion 50 that comes into contact.

On the other hand, the lower blade 56 is constituted by one lower blade roller 56R provided on one side of the upper blade 52 (on the opposite side of the contact portion 50). The lower blade roller 56R is
It is formed in a flat cylindrical or columnar shape having a certain diameter.

One or more (two in FIG. 2) receiving rollers 40 having the same diameter as the lower blade 56 are provided adjacent to the lower blade 56. The lower blade 56 and the receiving roller 40 are attached to a shaft 80, rotate in a direction opposite to the upper blade 52, and transport the web 12 to be cut at a constant transport speed while supporting it. The receiving roller 4 disposed below the upper blade 52
0, the flank 4 gradually reduced in diameter toward the lower blade 56
0A is formed so that it does not accidentally come into contact with the upper blade 52 during cutting. In FIG. 3, the shape of the flank 40A is a shape curved in an arc shape, but any shape may be used as long as the upper blade 52 does not contact at the time of cutting.
For example, a shape in which the diameter is intermittently reduced (a so-called stepped shape) may be used.

The upper blade 5 constituting the cutting blade 26 on both sides in the width direction.
Reference numeral 8 denotes a flat, substantially conical shape whose diameter is reduced toward the inside, and, like the upper blade 52, has a predetermined contact angle with the upper surface 12A of the web 12 when the outer peripheral surface is located at the lowest position. The contact portion 48 contacts at an angle of θ2 (30 ° or more and 70 ° or less). In addition, the upper blade 58 is also
And rotates in synchronization with the web speed.

On the other hand, the lower blade 54 is constituted by a lower blade roller 54R provided outside the upper blade 58. The lower blade roller 54R is formed in a flat cylindrical or columnar shape having the same diameter as the lower blade roller 56R.
Further, a receiving roller 40 is provided further inside the lower blade 54. The lower blade 54 and the receiving roller 40 are attached to a shaft 80, rotate in a direction opposite to the upper blade 58, and transport the web 12 at a constant transport speed while supporting the web 12.

The upper blades 52 and 58 are mounted so that the bite amount D at the time of cutting is 500% or less of the thickness T of the web 12. The method of such position adjustment is not particularly limited. For example, by making the shaft 78 up and down, the shaft 7
The upper blade 8 and the upper blades 52 and 58 can be adjusted so as to approach or separate from the web 12 integrally.

The "bite amount" means that the lowermost portion of the upper blades 50, 58 at the time of cutting is the web 1
2 means the distance measured downward from the back surface 12B.
Therefore, in order to cut the web 12 reliably, it is preferable that at least the biting amount D is 70% or less of the thickness T of the web 12.

The shafts 78 and 80 on both sides in the width direction are used.
Is mounted on a base 46 that moves in the width direction of the web 12 along the rails 44. Therefore, when the base 46 moves, the upper blade 58 and the lower blade 54 also move in the width direction, so that the cutting width of the web 12 can be changed.

When the web 12 is cut (cut) using the slitter 10 of the present embodiment having such a configuration, the transported web 12 is divided into an upper blade 52 and a lower blade 5.
6, the web 2 is pinched by the rotation of the upper blade 58 and the lower blade 54, and the web 12 is cut at a predetermined position by applying a shearing force to the web 2 to form two webs. Further, the photopolymerizable lithographic printing plate 30 as a final product is obtained by cutting at a predetermined position by the running cutter 28.

The upper blades 52, 58 have their contact portions 50, 48
Have predetermined contact angles θ1 and θ2 (both from 30 ° to 70 °) with respect to the upper surface of the web 12 (the surface on which the photosensitive layer is applied), and the shearing force acting on the web 12 at the time of cutting is It acts locally only on the part very close to the cutting edge, and there is no possibility that shear stress acts on a wide area.

FIG. 6 is a graph showing the relationship between the contact angles θ1 and θ2 and the remaining film width. This "remaining film width"
The residual film after development using the photopolymerizable lithographic printing plate 30 is magnified and observed with a loupe or the like.
In the width direction (same as the width direction of the web 12). In this graph, the maximum value per lithographic printing plate is taken.

As can be seen from this graph, the contact angle θ
1. When θ2 is 30 ° or more, the remaining film width is also 0.15 mm.
The remaining film is reduced to such an extent that there is no practical problem at all.

It is clear from this graph that the contact angles θ1 and θ2 should be made smaller in order to reduce the remaining film width. However, it is possible to prevent the cutting edge of the upper blade from being chipped or worn out. In order to increase the durability, the contact angles θ1 and θ2 should be 7
0 ° or less (ie, increase the angle of the cutting edge)
Is preferred.

The bite amount D of the upper blades 52, 58 is
The thickness of the web 12 is set to 70% or more and 500% or less of the thickness T, and the web 12 is reliably cut by applying a shearing force without excessively pressing the web 12 at the time of cutting.

Thus, the slitter 10 according to the present embodiment is
Layer 5 of photopolymerizable lithographic printing plate 30 cut by
No pressure acts on the contact portions 50 and 48 at the time of cutting, and no deformation occurs due to the intrusion of the contact portions 50 and 48 in the cutting 4, and no pressure fogging occurs. Therefore, even when developing using the photopolymerizable lithographic printing plate 30, a so-called residual film does not occur.

In the slitter of this embodiment, the web 12 is cut by setting the contact angles θ1 and θ2 of the upper blades 52 and 58 and the bite amount D in specific ranges. As shown in FIG. 2, it is also possible to arrange the contact portions 50, 48 of the upper blades 52, 58 on the side to be cut into a product. Then, as can be seen from FIG. 2, the web 12 can be cut at one place by the cutting blade 24 that cuts the web 12 at substantially the center. For this reason, what is called punching waste does not occur at the time of cutting, and cutting can be performed without waste. On the other hand, as shown in FIG. 4, for example, when it is necessary to arrange the contact portion 50 so as to be located on the side opposite to the product side, two upper blade rollers 52R arranged in parallel To the contact surface 50
Are arranged to face inward to form the upper blade 52,
The web 12 between these blades becomes punched waste 60.

In the above description, the slitter 10 capable of forming two products along the transport direction of the web 12 has been described. However, the photopolymerizable lithographic printing plate cutting device of the present invention is not limited thereto. Of course. For example, a slitter that can form more products along the transport direction of the web 12 may be used.

Further, the present invention is not limited to the slitter.
The photopolymerizable lithographic printing plate cutting device and the photopolymerizable lithographic printing plate cutting method of the present invention may be applied to the running cutter 28 shown in FIG. In this case, for example, as shown in FIG. 5, the upper blade 132 having the contact portion 136 formed on each of the upstream side and the downstream side in the transport direction (the direction of the arrow F) of the web 12, and the upper blade 132 It is preferable that a lower blade 134 for sandwiching and cutting the web 12 therebetween is provided to form the running cutter 28.

In consideration of the fact that the cut length of the web 12 varies depending on the size of the product, at least one of the inter-running cutters 28 may be movable in the transport direction of the web 12.

Further, only one inter-running cutter 28 is provided,
A desired cutting length may be obtained by controlling the cutting timing by the running cutter 28. In this case, the overall length of the processing line 90 can be reduced.

Also, the slitter for cutting (cutting) along the longitudinal direction of the web 12 and the running cutter 28 for cutting along the width direction of the web 12 have been described as different examples. The processing line may be provided with both a slitter and a running cutter.

Further, not only the processing line 90 for sequentially unwinding and processing the web 12 coated with the photosensitive layer 54 and wound into a coil as described above, but also the photosensitive layer 54
After processing, it is applied to processing lines that incorporate various processes, such as a processing line that continuously processes without winding, a processing line that winds into a coil after processing, and a final shipment after cutting into a master sheet. The photopolymerizable lithographic printing plate cutting device and the photopolymerizable lithographic printing plate cutting method of the present invention can be applied to a process of cutting into a sheet shape so as to have the form dimensions. As for the mode of transporting the web 12, not only the processing line for transporting the web with the photosensitive layer 54 facing upward,
A processing line for transporting the photosensitive layer 54 downward, or a processing line for transporting the web 12 in a vertical position so that the width direction thereof is up and down, may be used.
Is not particularly limited as long as the relative position between the web 12 and the contact portion of the pair of cutting blades that contacts the photosensitive layer on the product side satisfies the relationship described above.

As described above, according to the photopolymerizable lithographic printing plate cutting apparatus and the photopolymerizable lithographic printing plate cutting method of the present invention, the contact surface 5 which comes into contact with the photosensitive layer of the photopolymerizable lithographic printing plate can be used.
Since the contact angles of 0 and 48 are within a predetermined range, and the bite amount D is within 500% of the thickness T of the web S portion 12, the photopolymerizable planographic printing plate (cut No so-called pressure fogging occurs on the web 12),
There is no residual film after development.

[0053]

According to the present invention, the contact portion of the photosensitive layer-side cutting blade with the photosensitive layer comes into contact with the photosensitive layer at the contact angle of 30 ° or more and 70 ° or less at the time of cutting. The bite amount is 70% or more and 500% of the plate thickness of the photopolymerizable lithographic printing plate.
Because of the following, pressure fogging does not occur due to cutting, and no residual film is generated during development of the photopolymerizable lithographic printing plate.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a processing line for a photopolymerizable lithographic printing plate having a slitter according to an embodiment of the present invention.

FIG. 2 is a front view showing a slitter according to an embodiment of the present invention.

FIG. 3 is a partially enlarged cross-sectional view showing a slitter according to an embodiment of the present invention.

FIG. 4 is a partially enlarged front view showing a slitter different from the present invention.

FIG. 5 is a schematic side view showing a case where the photopolymerizable lithographic printing plate cutting device of the present invention is used for a running cutter.

FIG. 6 is a graph showing a relationship between a contact angle and a residual film width.

FIG. 7 is a perspective view showing a conventional slitter.

FIG. 8 is a partially enlarged front view of a conventional slitter.

[Explanation of symbols]

 Reference Signs List 10 slitter (photopolymerizable lithographic printing plate cutting device) 22 upper blade (photosensitive layer side cutting blade) 24 cutting blade 28 running cutter (photopolymerizable lithographic printing plate cutting device) 48 contact portion 50 contact portion 132 upper blade (photosensitive) Layer side cutting blade)

Claims (3)

[Claims] 1. A photopolymerizable lithographic printing plate cutting apparatus for sandwiching a photopolymerizable lithographic printing plate in a thickness direction with at least a pair of cutting blades and cutting at a predetermined position, wherein the pair of cutting blades is constituted. The contact portion of the blade with the photosensitive layer of the photosensitive layer side cutting blade, which is located on the photosensitive layer side of the photopolymerizable lithographic printing plate, is at least 30 ° with respect to the photopolymerizable lithographic printing plate.
° or less, and the photosensitive layer side cutting blade is arranged so that the bite amount at the time of cutting is 70% or more and 500% or less of the plate thickness of the photopolymerizable lithographic printing plate. Cutting equipment for polymerizable lithographic printing plates. 2. A photopolymerizable lithographic printing plate cutting method for cutting a photopolymerizable lithographic printing plate at a predetermined position by at least a pair of cutting blades, wherein the photopolymerizable lithographic printing plate is a photopolymerizable lithographic printing plate. The contact portion of the photosensitive layer side cutting blade, which is located on the photosensitive layer side of the lithographic printing plate, with the photosensitive layer is 30 ° or more with respect to the photopolymerizable lithographic printing plate.
° and contacting at the same time or less, and sandwiching the photopolymerizable lithographic printing plate in the thickness direction so that the bite amount during cutting is 70% or more and 500% or less of the plate thickness of the photopolymerizable lithographic printing plate. A method for cutting a photopolymerizable lithographic printing plate, comprising: 3. A photopolymerizable lithographic printing plate that is cut at a predetermined position by at least a pair of cutting blades, wherein a blade constituting the pair of cutting blades is on a photosensitive layer side of the photopolymerizable lithographic printing plate. The contact portion of the photosensitive layer side cutting blade with the photosensitive layer is set at 30 ° or more with respect to the photopolymerizable lithographic printing plate.
° and not more than 70% of the thickness of the photopolymerizable lithographic printing plate during cutting, and cut in the thickness direction of the photopolymerizable lithographic printing plate. Sexographic printing plate.