JP2017154301A - Flexographic printing plate, manufacturing method of flexographic printing platte and manufacturing device of flexographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexographic printing plate capable of reducing mat side printing defects generated near a boundary of small points of a mat part and a net point parts in flexographic printing and achieving uniform highlight small points corresponding to highlight gradation of printing images on a printed matter, a manufacturing method of the flexographic printing plate and a manufacturing device of the flexographic printing plate.SOLUTION: A flexographic printing plate has an image part and a non-image part. The image part has a mat part which is a zone with a predetermined area percentage or more and a net point part having small points. The small points of the net point part have a first small point and a second small point, the first small point is positioned at the nearest from an outline of the mat part, the second small point is positioned away from the outline than the second small point and the mat part has a reference surface height. The first small point has a same height as the reference surface of the mat part or first difference Lfrom the reference surface height to an apex of the first small point and the second small point has second difference Lfrom the reference surface height to an apex of the second small point. The first difference Land the second difference Lis L<L.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flexographic printing plate, a flexographic printing plate manufacturing method, and a flexographic printing plate manufacturing device, and more particularly, to a flexographic printing plate, a flexographic printing plate manufacturing method, and a flexographic printing plate manufacturing device with high printing accuracy.

A flexographic printing plate having a flexible image-forming layer made of resin or rubber has a relatively soft convex portion for printing as an image portion and can follow various shapes. It is used for printing on a thick substrate.
A flexographic printing plate is formed with a halftone dot portion composed of a large number of convex small dots, and by changing the size or density of the small dots in the halftone dot portion, an image printed on a substrate is printed. The concentration can be changed. Various manufacturing methods of a flexographic printing plate are described in Patent Document 1, for example.

Patent Document 1 describes a method of manufacturing a flexographic printing plate called a “mask CTP (computer to plate) method”. In the “mask CTP method”, a mask layer disposed on a photosensitive resin layer is burned off with a laser and then photocured, and an unexposed portion is washed away to form an image portion. At this time, oxygen in the atmosphere inhibits the polymerization of the photosensitive resin, and the edge at the upper part of the halftone dot is rounded. If the dot size is small, the halftone dot height level is lowered. .
In addition, a method of manufacturing a flexographic printing plate called “direct engraving CTP (computer to plate) method” is described. The “direct engraving CTP method” forms a relief directly on the original plate while controlling the engraving depth with the laser light quantity, but the engraving is performed while overlapping the laser spots, so the edge at the top of the halftone dot is rounded. Therefore, when the halftone dot size is small, the halftone dot height level is lowered.

  The decrease in the halftone dot height level generated in the above-described “mask CTP method” and “direct engraving CTP method” is a decrease in the height level of the small dot at the halftone dot portion which is not intended. Generally determined by the size of halftone dots. The above-described unintended reduction in the height level of the small dots in the halftone dot portion is also referred to as gradual lowering. When the solid portion 102 and the dot portion 104 are adjacent to each other as in the flexographic printing plate 100 shown in FIG. The halftone dot height Dh is lower than the reference surface height Bh which is the surface 102a of the solid portion 102. The difference δ between the reference surface height Bh and the halftone dot height Dh is referred to as the amount of layer reduction.

When the height level of the small dot in the halftone dot portion described above is reduced, if a solid portion with a high height level and a small dot with a low height level are adjacent to each other, it is difficult to apply printing pressure at the time of printing. There is a problem that the small dots of the halftone dot near the boundary of the halftone dot portion are faint or the small dots near the boundary are not printed, that is, a solid side printing defect occurs.
Here, as a specific example of the solid side printing defect, when printing is performed using image data representing the image 106 having the image portion 109 inside the solid frame 108 as illustrated in FIG. 23, the image 110 illustrated in FIG. As described above, in the image portion 114 corresponding to the image portion 109, there is a portion that is not printed on the inner peripheral edge 112b of the solid image portion 112.

Japanese Patent No. 5137618 Japanese Patent No. 5547543

On the other hand, in flexographic printing, there is a problem that the highlight dot corresponding to the highlight gradation of the printed image becomes fat due to the indentation pressure during printing. Techniques for lowering the height level are known. However, in this case as well, a solid side printing defect occurs near the boundary between the small portions of the solid portion and the halftone dot portion.
Patent Document 2 describes a method for solving the problem of solid side printing defects having halftone dot protrusions formed adjacently and having different height levels in a flat halftone region. However, in the above-described method of Patent Document 2, it is necessary to increase the size of the small dots of the halftone dots until an unintended height level drop does not occur. In this case, there arises a problem that the large and small halftone dot structure on the flat screen of the flexographic printing plate is visually recognized as the roughness of the printed matter.

  An object of the present invention is to solve the problems based on the above-described conventional technology, reduce solid side printing defects that occur near the boundary between the small portions of the solid portion and the halftone portion in flexographic printing, and highlight the printed image. An object of the present invention is to provide a flexographic printing plate, a flexographic printing plate manufacturing method, and a flexographic printing plate manufacturing apparatus that can uniformly reproduce highlight dots corresponding to gradation on a printed material.

In order to achieve the above-described object, the present invention provides a flexographic printing plate having an image portion and a non-image portion, the image portion having a solid portion that is an area having a predetermined area ratio or more, and a small dot. A halftone dot portion including a first dot and a second dot, the first dot being closest to the outline of the solid portion, the second dot The small point is located at a position farther from the outline than the first small point, the solid portion has the reference surface height, and the first small point is the same as the reference surface height of the solid portion or the reference point There is a first difference L ₁ from the surface height to the vertex of the first small point, and the second small point is a second difference L ₂ from the reference surface height to the vertex of the second small point. The first difference L ₁ and the second difference L ₂ provide a flexographic printing plate characterized by L ₁ <L ₂ .
The small dot of the average height of the halftone dot portion located farther from the contour than the second small dot has a difference Ld from the reference surface height to the vertex of the small dot, and the second difference L ₂ and the difference Ld are preferably L ₂ ≦ Ld.
It is preferable that the 1st small point and the 2nd small point exist in the range of 2 mm from the outline of a solid part.

  The present invention is a method of manufacturing a flexographic printing plate having a non-image portion and an image portion, the step of obtaining original image data of an image to be printed, the step of correcting the original image data and obtaining corrected image data, Obtaining halftone image data from the corrected image data; obtaining output image data for processing the flexographic printing plate precursor based on the halftone image data; and flexographic printing plate precursor based on the output image data. And the step of obtaining corrected image data includes a first correction intensity function whose value monotonously decreases as the level value of the pixel increases with respect to the pixels of the original image data, and the original image data in advance. A flexographic mark, wherein correction of original image data is corrected using a second correction strength function whose value monotonously decreases as the distance from a solid image portion that is an area of a predetermined area ratio or more increases. It is intended to provide a process for the production of the plate.

  The first correction intensity function and the second correction intensity function are: a solid part, a solid image part obtained by printing a plate making having a plurality of flat mesh image parts having different level values, and a solid image part obtained by the solid part. The image information of the solid image portion and the highlight portion of the chart image is obtained using the chart image having the highlight portion obtained by the plurality of flat mesh image portions having different level values, and the first information is obtained based on the image information. It is preferable to obtain a correction intensity function and a second correction intensity function.

  The present invention is a flexographic printing plate manufacturing apparatus having a non-image portion and an image portion, an acquisition portion that acquires original image data of an image to be printed, and a correction portion that corrects the original image data and obtains corrected image data A halftone dot image data obtaining unit for obtaining halftone dot image data from the corrected image data, an output image data obtaining unit for obtaining output image data for processing the flexographic printing plate precursor based on the halftone dot image data, and an output A correction unit that processes the flexographic printing plate precursor based on the image data, and the correction unit has a first correction intensity whose value monotonously decreases as the pixel level value increases with respect to the pixels of the original image data The correction of the original image data is corrected using the function and the second correction strength function whose value monotonously decreases as the distance from the solid image portion that is an area of a predetermined area ratio or more in the original image data increases. That There is provided a flexographic printing plate manufacturing apparatus according to symptoms.

  Obtained with a solid image portion obtained by printing a plate making having a solid portion and a plurality of flat mesh image portions having different level values, and a solid image portion obtained by a solid portion and a plurality of flat mesh image portions having different level values. A correction amount for obtaining a first correction intensity function and a second correction intensity function based on the image information, an image information acquisition section for acquiring image information of the solid image section and the highlight section, and a chart image having a highlight section It is preferable to include a calculation unit and a correction calculation unit that corrects the pixel value of the original image data using the first correction intensity function and the second correction intensity function.

According to the flexographic printing plate of the present invention, in flexographic printing, solid side printing defects that occur in the vicinity of the boundary between the small dots of the solid portion and the halftone dot portion are reduced, and the highlight smallness corresponding to the highlight gradation of the printed image is reduced. The dots can be reproduced uniformly on the printed matter.
Further, according to the method for manufacturing a flexographic printing plate of the present invention and the apparatus for manufacturing a flexographic printing plate of the present invention, solid side printing defects that occur near the boundary between a small portion of a solid portion and a halftone dot portion are reduced, and printing is performed. It is possible to obtain flexographic printing that can uniformly reproduce highlight dots corresponding to the highlight gradation of an image on a printed matter.

It is a top view which shows the 1st example of the printing plate of embodiment of this invention. It is a schematic diagram which shows an example of the image part of the printing plate of embodiment of this invention. It is a typical sectional view showing layer composition of the 1st example of a printing plate of an embodiment of the present invention. It is a schematic diagram for demonstrating the solid part of the printing plate of embodiment of this invention. It is a typical sectional view showing the 1st example of a printing plate of an embodiment of the present invention. It is typical sectional drawing which shows the 2nd example of the printing plate of embodiment of this invention. It is typical sectional drawing which shows the 3rd example of the printing plate of embodiment of this invention. It is typical sectional drawing which shows the 4th example of the printing plate of embodiment of this invention. It is a schematic diagram which shows the pixel which comprises a halftone dot. It is a graph which shows the relationship between a halftone dot size and the amount of layer reduction. It is a schematic diagram which shows an example of the printing plate manufacturing apparatus of embodiment of this invention. It is a schematic diagram which shows an example of the correction | amendment part of the printing plate manufacturing apparatus of embodiment of this invention. It is a flowchart which shows an example of the manufacturing method of the printing plate of embodiment of this invention. It is a flowchart which shows an example of the calculation method of the correction image data of the manufacturing method of the printing plate of embodiment of this invention. It is a schematic diagram which shows an example of the chart image used for the manufacturing method of the printing plate of embodiment of this invention. It is a graph which shows an example of the 1st correction intensity function. It is a graph which shows an example of the 2nd correction intensity function. It is a schematic diagram which shows an example of the pixel of correction | amendment object. It is a typical sectional view showing an example of a printing plate which is not amended. It is a schematic diagram which shows notionally the structure of the calender roll used for preparation of a flexographic printing plate precursor. It is a schematic diagram which shows notionally the structure of a flexographic printing apparatus. It is a schematic diagram for demonstrating the lowering of the growth. It is a schematic diagram which shows the image represented by image data. It is a schematic diagram for demonstrating a printing defect.

Hereinafter, based on preferred embodiments shown in the accompanying drawings, a flexographic printing plate, a flexographic printing plate manufacturing method, and a flexographic printing plate manufacturing apparatus according to the present invention will be described in detail.
In the following, “to” indicating a numerical range includes numerical values written on both sides. For example, when ε is a numerical value α to a numerical value β, the range of ε is a range including the numerical value α and the numerical value β, and expressed by mathematical symbols, α ≦ ε ≦ β.
Angles such as “orthogonal” and “same”, “all” and “entire surface” generally include an allowable error range.

FIG. 1 is a plan view illustrating a first example of a printing plate according to an embodiment of the present invention, and FIG. 2 is a schematic diagram illustrating an example of an image portion of the printing plate according to the embodiment of the present invention.
A flexographic printing plate 10 shown in FIG. 1 has an image portion 12 and a non-image portion 11. The non-image portion 11 is a region where ink is not adhered during printing, that is, the non-image portion 11 is a region where an image is not formed during printing. The image unit 12 attaches ink at the time of printing, and transfers the ink to a printing medium. That is, the image portion 12 is an area where an image is formed during printing.
As shown in FIG. 2, the image portion 12 of the flexographic printing plate 10 includes a solid portion 13 and a halftone dot portion 14 having small dots 15 (see FIG. 5). 2 indicates the outline of the solid portion 13.

The solid portion 13 is a region having a predetermined area ratio or more, and is printed so as to be filled by transferring ink entirely. The shape and arrangement position of the solid portion 13 are appropriately determined according to the image to be printed.
The halftone dot portion 14 is composed of a large number of convex small dots 15, and expresses the lightness and darkness of an image printed on the printing medium by changing at least one of the size and density of the small dots 15. It is an area. The size of the small point 15 can be adjusted by the height of the small point 15, for example. In this case, if the size of the small point 15 is reduced, the height of the small point 15 is reduced. That is, a difference from a later-described reference surface height Bh to the apex 17 of the small point 15 increases.
The small dots 15 constituting the halftone dot portion 14 are usually formed with a predetermined number of screen lines, for example, about 100 to 175 lpi (line per inch).

  As shown in FIG. 3, for example, the flexographic printing plate 10 is provided with an image forming layer 22 on a support 20. The distance from the back surface 20b of the support 20 to the front surface 22a of the image forming layer 22 is the plate thickness t. The surface 22a of the image forming layer 22 is the reference surface, and the plate thickness t is the reference surface height Bh. The above-described image portion 12 is formed on the image forming layer 22, but the surface 22a of the image forming layer 22 coincides with the surface of the solid portion 13 (see FIG. 4). The flexographic printing plate 10 shown in FIG. 3 shows a state before the image portion 12 is formed, and this state is also called a flexographic printing plate precursor.

In the solid portion 13, the surface 22 a of the image forming layer 22 remains even after the image portion 12 is formed on the image forming layer 22 as shown in FIG. 4. For this reason, when the cross-sectional shape of the flexographic printing plate 10 including the reference surface height Bh is observed, the top portion 13a of the solid portion 13 is flat. From this, it is possible to determine whether or not the solid portion 13 is obtained by obtaining the area ratio of the top portion 13a that is flat.
The reference surface height Bh represents the same height as the top portion 13a of the solid portion 13 and represents the relative height. That is, the height of the small dot 15 of the halftone dot portion 14 is considered based on the reference surface height Bh.
Here, the solid portion 13 is a region having an area ratio of 30% or more. The area ratio is a value measured in a range of 1 mm square. The lower limit of the solid portion 13 is a region having a diameter of 100 μm in terms of a circle in terms of the size of the region.
About the solid part 13, the magnitude | size of an area | region can be specified using an optical microscope, it can be specified whether it is the solid part 13, and also the magnitude | size of the solid part 13. FIG.

As shown in FIG. 5, the dot 15 of the halftone dot portion 14 includes a first dot 15a and a second dot 15b. The first small point 15a is located closest to the outline E of the solid portion 13, and the second small point 15b is located farther from the outline E than the first small point 15a. As described above, the solid portion 13 has the reference surface height Bh. First small point 15a has a first difference _{L 1} from the reference plane height Bh to the apex 17 of the first small dot 15a. Second small point 15b includes a second difference _{L 2} from the reference plane height Bh to the apex 17 of the second small point 15b. The first difference L ₁ and the second difference L ₂ described above are L ₁ <L ₂ .

Furthermore, in FIG. 5, it has the 3rd small point 15c. The third small point 15c is lower than the second small point 15b and is located farther from the contour E than the second small point 15b. Third lower point 15c has a third difference _{L 3} from the reference plane height Bh to the apex 17 of the third sub-point 15c. The dot 15v having the average height Dv of the halftone dot portion 14 is located farther from the contour E than the third dot 15c. The small point 15v having the average height Dv of the halftone dot portion 14 has a difference Ld from the reference surface height Bh to the vertex 17 of the small point 15v. In Figure 5, the first difference _{L 1} and the second difference _{L 2} and the third difference _{L 3} and difference Ld described above _is L ₁ <L _{2 <L} 3 <Ld.
The second small point 15b has a height that is equal to or exceeds the average height Dv of the small points 15v of the halftone dot portion 14 located farther from the contour E than the second small point 15b. It is preferable. In this case, the second difference L ₂ and the difference Ld are preferably L ₂ ≦ Ld.

In FIG. 5, the dot 15 of the halftone dot portion 14 has a height corresponding to the distance from the outline E of the solid portion 13, and the first dot 15a, the second dot 15b, and the third dot 15b. When connecting the vertices 17 of the small point 15c, a straight line S that starts from the contour E and monotonously decreases in the range from the reference surface height Bh to the average height Dv is drawn.
It is preferable that the first small point 15a, the second small point 15b, and the third small point 15c exist within a range RD of 2 mm from the outline E of the solid portion 13. In the range RD of 2 mm, for example, about 10 dot dots are included.
If the first small point 15a, the second small point 15b, and the third small point 15c are present within a range RD of 2 mm from the outline E of the solid portion 13, it is possible to suppress the occurrence of a solid side printing defect. It is enough.

  In the flexographic printing plate 10, the flexographic printing plate 100 shown in FIG. The first small point 15a, the second small point 15b, and the third small point 15c in the vicinity of the boundary between the outline E of the solid portion 13 and the halftone dot portion 14 are subjected to printing pressure during printing, and the first small point 15a The point 15a, the second small point 15b, and the third small point 15c are printed without fading. In this case, for example, the dot ratio corresponding to the highlight gradation of the printed image, with a dot ratio of more than 0% and not more than 10%, is reduced in the conventional flexographic printing plate. The decrease in height can be suppressed. For this reason, even a small dot corresponding to the above-described highlight gradation can be printed without fading. Thereby, the solid side printing defect generated near the boundary between the outline E of the solid portion 13 and the halftone dot portion 14 can be reduced. In addition, it is possible to uniformly reproduce the highlight dot corresponding to the highlight gradation of the printed image on the printed matter.

The first small dot 15a may be any one having a first difference L ₁ from the same or a reference plane height Bh a reference plane height Bh of the solid portion 13 to the apex 17 of the first small dot 15a The image portion 12 of the flexographic printing plate 10 is not limited to the configuration shown in FIG. For example, the first small point 15a may be the same as the reference surface height Bh as in the image portion 12 shown in FIG.
Further, as in the image portion 12 shown in FIG. 7, the first small points 15a having the same vertex 17 as the reference plane height Bh are arranged side by side in the direction away from the contour E, and further have the second small points 15b. It may be configured. In FIG. 7, the first small point 15a and the second small point 15b exist between the outline E of the solid portion 13 and the small point 15 having the average height Dv. Also in the image portion 12 shown in FIG. 7, the first small point 15 a and the second small point 15 b are present in the range RD of 2 mm from the outline E of the solid portion 13 as in the image portion 12 shown in FIG. 5. preferable.

Also, as shown in FIG. 8, the first small point 15a, the second small point 15b, the third small point 15c, and the fourth small point 15d are arranged in this order from a position close to the contour E. But you can. The fourth sub-point 15d has a fourth difference _{L 4} from the reference plane height Bh to the apex 17 of the fourth small dot 15d. The first difference L ₁ , the second difference L ₂ , the third difference L ₃ , the fourth difference L _4, and the difference Ld are L ₁ <L ₂ <L ₃ <L ₄ <Ld. That is, the fourth small point 15d is lower than the third small point 15c and higher than the average height Dv.
Also in the image portion 12 shown in FIG. 8, the first small point 15 a, the second small point 15 b, the third small point 15 c, and the fourth small point 15 d are similar to the image portion 12 shown in FIG. It is preferable that it exists in the range RD of 2 mm from the outline E.

Even in the configuration of the image portion 12 shown in FIGS. 6 to 8, the solid side printing defects can be reduced similarly to the image portion 12 shown in FIG. 5, and the highlight dot corresponding to the highlight gradation of the print image is printed. Can be reproduced uniformly above.
In addition, in the image part 12 shown in FIGS. 6-8, the same code | symbol is attached | subjected to the same structure as the image part 12 shown in FIG. 5, and the detailed description is abbreviate | omitted.
The height of the dot 15 of the halftone dot portion 14 of the image portion 12 including the first dot 15a, the second dot 15b, the third dot 15c, and the fourth dot 15d described above is optical. Using a microscope, the cross section of the flexographic printing plate 10 can be observed and identified from the cross section image. In this case, the top portion 13a of the solid portion 13 is specified, and the top portion 13a of the solid portion 13 is set as the reference surface height Bh. Then, the distance from the reference surface height Bh to the vertex 17 of the small point 15 is obtained. Thereby, the above-mentioned first difference L _{1 and the} like can be obtained.

Next, a flexographic printing plate manufacturing apparatus and a flexographic printing plate manufacturing method will be described.
FIG. 9 is a schematic diagram showing pixels constituting a halftone dot, and FIG. 10 is a graph showing the relationship between the halftone dot size and the amount of layer reduction.
The inventor uses FLENEX DLE Setter DL-50 (product name, manufactured by FUJIFILM Corporation) and is a flexo version of DLE flexographic plate FLEXEX FD-H (manufactured by FUJIFILM Corporation) with a resolution of 2540 dpi (dot per inch). When engraving, the number of pixels that generally constitute halftone dots is less than 10 pixels, such as the pixels 24a, 24b, 24c, and 24d shown in FIG. 9, and unintentionally lowering, that is, gradually lowering (see FIG. 22). Found that occurs. In this case, the halftone dot size and the lowering amount δ are in the relationship shown in FIG. 10, and it has been found that the lowering amount δ (see FIG. 22) of the lowering layer gradually increases as the halftone dot size decreases.
The pixel 24a shown in FIG. 9 is 1 pixel, the pixel 24b is 2 pixels, the pixel 24c is 3 pixels, and the pixel 24d is 4 pixels.

As a method for controlling the lowering amount δ (see FIG. 22) of the above-described lowering of the layers, a method for correcting the dot size has been found and the present invention has been achieved. Since the amount of lowering δ (see FIG. 22) for the lowering of the number of layers is substantially determined by the dot size, the correction amount for the dot area ratio depends on the number of lines on the screen.
The stress applied to the small point close to the reference surface height Bh (see FIG. 5), for example, the top of the first small point 15a (see FIG. 5) is the small point 15v of the single halftone dot part 14 (see FIG. 5). Compared to (see FIG. 5), the halftone dot thickness at the time of printing is minimized, so that halftone dots having a uniform size at the time of printing can be reproduced. As a result, solid side printing defects can be reduced, and the small dots of the halftone dots can be reproduced uniformly on the printed matter.

Next, the printing plate manufacturing apparatus and the printing plate manufacturing method will be described more specifically.
FIG. 11 is a schematic diagram illustrating an example of a printing plate manufacturing apparatus according to an embodiment of the present invention. FIG. 12 is a schematic diagram illustrating an example of a correction unit of the printing plate manufacturing apparatus according to an embodiment of the present invention.
FIG. 13 is a flowchart illustrating an example of a printing plate manufacturing method according to an embodiment of the present invention, and FIG. 14 is a flowchart illustrating an example of a method for calculating corrected image data in a printing plate manufacturing method according to an embodiment of the present invention. .

A printing plate manufacturing apparatus 30 shown in FIG. 11 is a manufacturing apparatus for a flexographic printing plate 10 (see FIG. 1) having a non-image portion 11 (see FIG. 1) and an image portion 12 (see FIG. 1).
The manufacturing apparatus 30 includes an acquisition unit 32 that acquires original image data of an image to be printed, a correction unit 34 that corrects the original image data to obtain corrected image data, and a halftone image that obtains halftone image data from the corrected image data. A data acquisition unit, an output image data acquisition unit for obtaining output image data for processing the flexographic printing plate precursor based on the halftone dot image data, and a flexographic printing plate precursor processed based on the output image data And a processing unit 40.

Furthermore, it has a memory 42 for storing various data obtained by the acquisition unit 32, the correction unit 34, the halftone image data acquisition unit 36, and the output image data acquisition unit 38, and various types of input data. The memory 42 also stores processing conditions and the like in the processing unit 40.
Each component of the acquisition unit 32, the correction unit 34, the halftone image data acquisition unit 36, the output image data acquisition unit 38, the processing unit 40, and the memory 42 is controlled by the control unit 44.
An image data supply unit 46 that supplies original image data of an image to be printed to the manufacturing apparatus 30 is connected to the manufacturing apparatus 30. The image data supply unit 46 is connected to the acquisition unit 32 or the memory 42, for example. When the image data supply unit 46 is connected to the memory 42, the acquisition unit 32 acquires the original image data from the memory 42.

The acquisition unit 32, the correction unit 34, the halftone image data acquisition unit 36, the output image data acquisition unit 38, and the control unit 44 are configured using hardware such as a computer, for example.
If the processing part 40 can process a printing plate precursor and can manufacture a printing plate, the structure will not be specifically limited, For example, what engraves a printing plate precursor using a laser etc. can be utilized suitably. It is. When a laser is used, processing methods include the above-described “mask CTP (computer to plate) method” and “direct engraving CTP (computer to plate) method”.

The correction unit 34 has a first correction intensity function whose value monotonously decreases as the level value of the pixel increases with respect to the pixels of the original image data, and a solid area that is an area greater than a predetermined area ratio in the original image data. The correction of the original image data is corrected using the second correction strength function whose value monotonously decreases as the distance from the image portion increases. The first correction intensity function and the second correction intensity function will be described in detail later. The first correction strength function and the second correction strength function may be stored in the memory 42. In this case, the control unit 44 causes the correction unit 34 to read the first correction strength function and the second correction strength function, and executes correction.
Further, the correction unit 34 stores the correction amount of the pixel value at the specific pixel position and the pixel level value in advance in the lookup table instead of the first correction intensity function and the second correction intensity function described above. Alternatively, correction may be performed using a lookup table.
The lookup table may be stored in the memory 42. In this case, the correction unit 34 causes the control unit 44 to read the lookup table and executes correction. A more specific configuration of the correction unit 34 will be described later in detail. The level value of the pixel is the gradation of the pixel.

For example, when the corrected image data is in the vector format and the halftone image data is in the raster format, the halftone image data acquisition unit 36 converts the halftone image data to the corrected image data by, for example, RIP (Raster Image Processor) processing. obtain. For RIP (Raster Image Processor) processing, for example, a known vector data-raster data conversion program is used.
The output image data acquisition unit 38 converts the halftone dot image data into a data format that can be used by the processing unit 40 and creates output image data for processing the flexographic printing plate precursor. If the processing unit 40 can use the halftone image data as it is, it is not always necessary to create output image data.

In the printing plate manufacturing method, as shown in FIG. 13, first, original image data of an image to be printed is acquired (step S10).
Next, the original image data is corrected to obtain corrected image data (step S12). The process of obtaining the corrected image data will be described in detail later.
Next, halftone dot image data is obtained from the corrected image data (step S14). The halftone image data is obtained, for example, by performing RIP (Raster Image Processor) processing on the corrected image data. It should be noted that when the halftone image data is obtained, the number of print lines set in advance can be set.

Next, output image data for processing the flexographic printing plate precursor is obtained based on the halftone dot image data (step S16). The output image data has a data format that can be used by the processing unit 40 and is converted into a data format corresponding to the processing unit 40 to obtain output image data.
Next, the flexographic printing plate precursor is processed on the basis of the output image data under preset processing conditions (step S18). Thereby, for example, the flexographic printing plate 10 having the image portion 12 shown in FIG. 5 is obtained (step S20).
In step S18, when the flexographic printing plate precursor is processed, the flexographic printing plate precursor may be wound around a plate cylinder, or the flexographic printing plate precursor may be processed in a flat plate state.

  In the printing plate manufacturing method, halftone image data is not corrected, but original image data before obtaining halftone image data is corrected. The original image data is input data and has not been processed. Original image data is often in a vector format, and halftone image data is often in a raster format. The raster format requires more data than the vector format, and it takes time to correct the raster format. Therefore, by correcting the original image data and creating the corrected image data, the time until the output image data is obtained can be shortened, and the manufacturing efficiency of the flexographic printing plate can be increased.

Next, an example of correction will be described with reference to FIGS. 12, 14 and 15 to 18.
FIG. 15 is a schematic diagram showing an example of a chart image used in the printing plate manufacturing method of the embodiment of the present invention, FIG. 16 is a graph showing an example of the first correction strength function, and FIG. It is a graph which shows an example of the correction | amendment intensity function of. FIG. 18 is a schematic diagram illustrating an example of a correction target pixel.

The correction unit 34 corrects the original image data of the small dots adjacent to the outline E of the solid part 13 having the reference surface height Bh according to the distance from the outline E of the solid part 13. In flexographic printing plates, when the halftone dot height level differs depending on the halftone dot size, when a halftone dot with a high halftone dot is adjacent to a halftone dot with a low height, the height is gradually changed. to correct.
The original image data represents a print image, and the solid portion of the image portion of the flexographic printing plate determines a determination criterion, for example, by determining a region having a specific number of pixels or more as a solid portion, A solid part can be specified. Further, a range to be corrected for the solid outline may be set in advance. The solid part information and the correction range information in the original image data may be added to the original image data and supplied from the image data supply unit 46.

  For example, as illustrated in FIG. 12, the correction unit 34 acquires an image information acquisition unit 50 that acquires image information of a chart image, and correction that obtains a first correction intensity function and a second correction intensity function based on the image information. It has the quantity calculation part 52, and the correction calculating part 54 which correct | amends the pixel value of original image data using the 1st correction intensity function and the 2nd correction intensity function. The image information acquisition unit 50 is connected to the acquisition unit 32, and the correction calculation unit 54 is connected to the halftone image data acquisition unit 6.

  For the correction, for example, a chart image 60 shown in FIG. 15 is used. The chart image 60 is, for example, an image obtained by printing a plate making (not shown) having a solid part (not shown) and a plurality of flat mesh image parts (not shown) having different level values. The chart image 60 is an image having a solid image portion 62 obtained by the above-described solid portion and a plurality of highlight portions 64a to 64f obtained by a plurality of flat mesh image portions having different level values. The chart image 60 is represented by, for example, an 8-bit gradation in which the highlight is level 0 and the solid is level 255. The highlight portions 64a to 64f have different level values. For example, the highlight portion 64a is level 1, the highlight portion 64b is level 2, the highlight portion 64c is level 3, the highlight portion 64d is level 4, and the highlight portion 64e. Is level 5, and the highlight part 64f is level 6. The highlight parts 64a to 64f are provided at level 1 intervals.

The image information acquisition unit 50, for example, a scanner that optically reads the chart image 60, and a process for obtaining a correction range reference value, a distance correction range reference value, and a level correction reference value, which will be described later, based on the image information obtained by the scanner. Part (not shown). The scanner only needs to be able to read black and white, and the reading accuracy is appropriately determined according to the specifications required for the printing plate, and the reading gradation is, for example, 8 bits. The image information includes the pixel position and pixel gradation of the read image.
The chart information 60 shown in FIG. 15 is read by the image information acquisition unit 50. The image information acquisition unit 50 acquires image information of the solid image unit 62 of the chart image 60 and the plurality of highlight units 64a to 64f. The image information, the correction range reference value, the distance correction range reference value, and the level correction reference value are stored in, for example, the memory 42 (see FIG. 11).

The correction range reference value is a level value (p) of a pixel that requires solid side small dot correction.
The distance correction range reference value is a range in which solid side small dot correction is performed, that is, a distance (w) from the outline of the solid portion.
The level correction reference value is a level value (v) in which the size of the small dot closest to the outline of the solid portion is approximately the same as the level 1 flat image portion center. By the level correction reference value, it is possible to specify up to which pixel level value the solid side printing defect has occurred. The image positions of the solid image portion 62 of the chart image 60 and the plurality of highlight portions 64a to 64f can be specified at the time of reading, and the pixel value at the center of the level 1 highlight portion 64a is the center of the flat image portion. It corresponds to the level value. For each highlight portion 64b to 64f, the vicinity of the contour of the solid image portion 62 is set in advance, and the pixel value near the contour is compared with the pixel value at the center of the highlight portion 64a to set the level correction reference value. Can be specified. Note that the pixel value in the vicinity of the contour can be appropriately determined according to accuracy or the like, and is, for example, the average pixel value of the pixels in the vicinity of the contour.
An allowable value is set in advance for the difference between the pixel value in the center of the highlight portion 64a and the pixel value in the vicinity of the contour, and if the above difference is within the allowable value, Is approximately the same as the center of the level 1 flat image portion.
The level value (v) is preferably 4 or more, more preferably 6-10.

The correction amount calculation unit 52 obtains a first correction strength function and a second correction strength function from the correction range reference value, distance correction range reference value, and level correction reference value based on the image information.
The first correction intensity function is a correction intensity function corresponding to the level value of the pixel. As shown in FIG. 16, the first correction strength function fp is a function that takes the minimum value, that is, the maximum value at level 1, decreases as the level increases, and becomes 0 at level p. The first correction strength function fp has a value of 0 at all levels p and above.
The second correction strength function is a correction strength function corresponding to the distance from the solid portion outline. As shown in FIG. 17, the second correction strength function fw is a function that takes a maximum value at a distance 0, decreases as the distance increases, and becomes 0 at a distance w. The second correction intensity function fw takes a value of 0 for the distance w or more. The first correction strength function and the second correction strength function are stored in the memory 42 (see FIG. 11), for example.

The correction calculator 54 corrects the pixel value of the original image data using the first correction intensity function and the second correction intensity function. The correction calculation unit 54 calculates a correction amount for the pixel of interest from the first correction intensity function, the second correction intensity function, and the level correction reference value v, and corrects the pixel value Q (A). The correction amount can be obtained by the following mathematical formula. The mathematical formula is stored in, for example, the memory 42 (see FIG. 11).
Qc (A) = Q (A) + (v−1) × fp (Q) × fw (D)

In the above formula, Q (A) is a pixel value of an arbitrary pixel of the original image data. Qc (A) is a corrected pixel value of an arbitrary pixel, and is a pixel value of corrected image data. v is a level correction reference value, which indicates a level value of a pixel that needs to be corrected in an image state, that is, a gradation that needs to be corrected in an image state. D (A) is the distance from the outline of the solid portion having the reference plate surface height.
Here, the correction target image 66 shown in FIG. 18 is an image having an image portion 68 and a solid portion 69 and represented by the original image data. In the pixel of interest 67 of the image portion 68, when two orthogonal lines are drawn with the pixel of interest 67 as the center, the distance closest to the solid portion 69 in each line is D (A). In FIG. 18, the distance to the first edge 69a of the solid portion 69 is closer than the distance to the second edge 69b. Therefore, D (A) is a distance to the first edge 69a.
With respect to D (A), a correction range may be set in advance for the original image data, and the above-described D (A) may be obtained for pixels within the correction range. Thereby, the time for obtaining the corrected image data from the original image data can be shortened.

In the method of creating corrected image data, first, as shown in FIG. 14, a chart image 60 (see FIG. 15) is created (step S30). Next, image information is obtained by the image information acquisition unit 50 (see FIG. 12) (step S32). At this time, a correction range reference value, a distance correction range reference value, and a level correction reference value are obtained from the image information.
Next, from the correction range reference value, the distance correction range reference value, and the level correction reference value based on the image information, the first correction strength function fp (see FIG. 16) and the second correction strength function fw (see FIG. 17). Is obtained (step S34).

  Next, the pixel value of the pixel of the original image data is corrected using the first correction intensity function fp and the second correction intensity function fw (step S36). At this time, D (A) is obtained for the pixel, and the pixel value is corrected using the above formula. Thereby, the corrected image data can be obtained. The corrected image data is output to the halftone image data acquisition unit 36. The corrected image data may be stored in the memory 42 (see FIG. 11), for example.

  When the flexographic printing plate is manufactured without creating the corrected image data, for example, the small dot 15 of the halftone dot portion 124 including the small dot 15 closest to the outline E of the solid portion 122 as in the image portion 120 shown in FIG. All the points 15 become the average height Dv. In the flexographic printing plate having the image portion 120 shown in FIG. 19, the above-mentioned solid side printing defect occurs. On the other hand, a printing plate having the image portion 12 shown in FIG. 5 can be obtained by creating corrected image data. In the flexographic printing plate 10 shown in FIG. 5, solid side printing defects can be reduced as described above.

  The flexographic printing plate precursor is preferably engraved by laser engraving. There is a certain relationship between the laser light quantity and the engraving depth, and an arbitrary shape can be engraved on the printing plate precursor by controlling the light quantity. For this reason, it is preferable that the process part 40 (refer FIG. 11) uses a laser.

The laser engraving method is basically the same as the laser engraving method used in the conventional flexographic printing plate manufacturing method.
As a method of laser engraving, for example, a flexographic printing plate precursor for sheet-like laser engraving is wound around the outer peripheral surface of a drum having a cylindrical shape, the drum is rotated, and the above-mentioned exposure head is directed toward the flexographic printing plate precursor. By emitting laser light according to the output image data and scanning the exposure head in a sub-scanning direction orthogonal to the main scanning direction at a preset pitch, a two-dimensional image can be rapidly formed on the surface of the flexographic printing plate precursor. A method of engraving with can be used.

The type of laser used in laser engraving is not particularly limited, but an infrared laser is preferably used. When irradiated with an infrared laser, the molecules in the image forming layer undergo molecular vibrations and generate heat. When a high-power laser such as a carbon dioxide laser or a YAG laser is used as an infrared laser, a large amount of heat is generated in the laser irradiation portion, and molecules in the image forming layer are selectively cut by molecular cutting or ionization, that is, Sculpture is made. The advantage of laser engraving is that the engraving depth can be set arbitrarily, so that the structure can be controlled three-dimensionally. For example, the portion that prints fine halftone dots can be engraved shallowly or with a shoulder so that the dots of the halftone dot portion do not fall down due to printing pressure, and the grooves for printing fine cutout characters can be prevented. By deeply engraving the portion, it becomes difficult to fill the groove with ink, and it is possible to suppress the crushing of the extracted characters.
In particular, when engraving with an infrared laser corresponding to the absorption wavelength of the photothermal conversion agent, the image forming layer can be selectively removed with higher sensitivity, and an image portion with high molding accuracy can be obtained.

As the infrared laser, a carbon dioxide laser or a semiconductor laser is preferable from the viewpoint of productivity and cost, and a semiconductor infrared laser with a fiber is particularly preferable. In general, a semiconductor laser is more efficient in laser oscillation than a carbon dioxide laser, is inexpensive, and can be downsized. Moreover, since it is small, it is easy to form an array. Furthermore, the beam shape can be controlled by processing the fiber.
The semiconductor laser preferably has a wavelength of 700 to 1,300 nm, more preferably 800 to 1,200 nm, still more preferably 860 to 1,200 nm, and particularly preferably 900 to 1,100 nm.
In addition, a semiconductor laser with a fiber is effective for laser engraving because it can efficiently output laser light by further attaching an optical fiber. Furthermore, the beam shape can be controlled by processing the fiber. For example, the beam profile can have a top hat shape, and energy can be stably given to the plate surface. Details of the semiconductor laser are described in “Laser Handbook 2nd Edition” edited by Laser Society, “Practical Laser Technology” edited by IEICE.
Moreover, the plate making apparatus provided with the semiconductor laser with a fiber described in detail in Japanese Patent Application Laid-Open No. 2009-172658 and Japanese Patent Application Laid-Open No. 2009-214334 can be suitably used for the above-described processing.

  The method for producing the flexographic printing plate is not limited to laser engraving (DLE (Direct Laser Engraving) method), but the LAMS (Laser Abration Masking System) method for writing and developing images on the surface of the printing plate precursor with a laser. Various known manufacturing methods can be used.

[Flexographic printing plate precursor]
The flexographic printing plate precursor is not particularly limited as long as it is a known resin plate or rubber plate for flexographic printing. Further, the printing plate precursor may be a sheet or a cylinder.
The flexographic printing plate precursor preferably has the following resin sheet as an image forming layer.

<Resin sheet>
As the resin sheet, a curable resin composition containing at least a polymer having a monomer unit derived from a diene hydrocarbon (hereinafter, also referred to as “resin composition for forming a resin sheet”) is formed into a sheet shape. It is preferably a sheet cured by the action of heat and / or light, and more preferably formed by a resin composition for forming a resin sheet described later.
Moreover, it is preferable that the above-mentioned resin sheet can be laser engraved.

As a method for forming a resin sheet, a resin composition for forming a resin sheet is prepared, and if necessary, after removing the solvent from the resin composition, it is melt-extruded on a support, or a resin for forming a resin sheet A composition is prepared, the above-mentioned resin composition is cast on a support, and this is heated and dried in an oven or the like to remove the solvent, using a calendar roll as shown in FIG. A preferred example is a method of molding the resin composition into a sheet.
In FIG. 20, the calendar roll 70 has first to fourth rolls 72a to 72d, and the interval between the rolls, the temperature of the rolls, and the rotation speed of the rolls can be set. The kneaded material 80 is set between the rolls, and the resin sheet 81 can be obtained by rolling.

<Support>
When using a support for forming a resin sheet, the material used for the support is not particularly limited as long as it can be mounted on a printing cylinder, but a material with high dimensional stability is preferably used. Synthesis of metals such as steel, stainless steel and aluminum, for example, polyesters such as PET (polyethylene terephthalate), PBT (polybutylene terephthalate), and PAN (polyacrylonitrile), plastic resins such as polyvinyl chloride, styrene-butadiene rubber, etc. Examples thereof include a plastic resin such as an epoxy resin or a phenol resin reinforced with rubber or glass fiber. As the support, a PET film and a steel substrate are preferably used.

  The resin composition for forming a resin sheet is prepared by, for example, dissolving or dispersing a polymer having a monomer unit derived from a diene hydrocarbon, a polymerizable compound, a fragrance, a plasticizer, and the like in an appropriate solvent, and then a crosslinking agent, It can be produced by dissolving a polymerization initiator, a crosslinking accelerator and the like. From the viewpoint of the ease of forming the resin sheet, the thickness accuracy of the obtained cylindrical printing plate precursor, and the handling of the resin sheet, at least a part of the solvent component is preferably almost all of the cylindrical printing plate precursor. Since it is necessary to remove at the stage of production, an organic solvent having moderate volatility is preferable as the solvent.

  Next, components included in the resin sheet and the resin composition for forming a resin sheet will be described.

(Polymer having monomer units derived from diene hydrocarbon)
The resin sheet preferably contains a polymer having a monomer unit derived from a diene hydrocarbon (hereinafter also referred to as “specific polymer”) as an essential component.
The weight average molecular weight of the specific polymer is preferably from 50,000 to 1,600,000, more preferably from 10,000 to 1,000,000, and even more preferably from 15,000 to 600,000. When the weight average molecular weight is 50,000 or more, the form retainability as a single resin is excellent, and when it is 1.6 million or less, it is easy to dissolve in a solvent and it is convenient for preparing a resin composition for laser engraving.
The weight average molecular weight is measured by gel permeation chromatography (GPC) and is determined by conversion with standard polystyrene. Specifically, for example, gel permeation chromatography uses HLC-8220GPC (manufactured by Tosoh Corporation), and TSKgeL SuperHZM-H, TSKgeL SuperHZ4000, TSKgeL SuperHZ2000 (manufactured by Tosoh Corporation, 4.6 mm ID × 15 cm) as columns. 3) and THF (tetrahydrofuran) as eluent. As conditions, the sample concentration is 0.35% by mass, the flow rate is 0.35 ml / min, the sample injection amount is 10 μL, the measurement temperature is 40 ° C., and an IR (infrared) detector is used. In addition, the calibration curve is “Standard sample TSK standard, polystyrene” manufactured by Tosoh Corporation: “F-40”, “F-20”, “F-4”, “F-1”, “A-5000”, “ It is prepared from 8 samples of “A-2500”, “A-1000” and “n-propylbenzene”.

  The specific polymer may be a specific polymer having a monomer unit derived from a non-conjugated diene hydrocarbon, but is preferably a specific polymer having a monomer unit derived from a conjugated diene hydrocarbon.

(Specific polymer having monomer units derived from conjugated diene hydrocarbon)
Specific polymers having monomer units derived from conjugated diene hydrocarbons include polymers obtained by polymerizing conjugated diene hydrocarbons, conjugated diene hydrocarbons and other unsaturated compounds, preferably mono Preferred examples include copolymers obtained by polymerizing olefinic unsaturated compounds. The above-mentioned polymers and copolymers may be modified, for example, a reactive group such as a (meth) acryloyl group may be introduced at the terminal, and a part of the internal olefin is hydrogenated. May be. In the following description, polybutadiene in which part of the internal olefin is hydrogenated is also referred to as “partially hydrogenated polybutadiene”, and similarly, polyisoprene in which part of the internal olefin is hydrogenated is also referred to as “partially hydrogenated polyisoprene”. . Further, the copolymer may be a random polymer, a block copolymer, or a graft polymer, and is not particularly limited.

Specific examples of the conjugated diene hydrocarbon include 1,3-butadiene, isoprene and the like. These compounds are used alone or in combination of two or more.
Specific examples of the monoolefin unsaturated compound described above include, for example, styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, isobutene, vinyl chloride, vinylidene chloride, (meth) acrylamide, (meta ) Acrylamide vinyl acetate, (meth) acrylic acid ester, (meth) acrylic acid and the like.

  The polymer obtained by polymerizing the conjugated diene-based hydrocarbon or the copolymer obtained by polymerizing the conjugated diene-based hydrocarbon and the monoolefin unsaturated compound is not particularly limited. Specifically, Butadiene polymer, isoprene polymer, styrene-butadiene copolymer, styrene-isoprene copolymer, acrylate ester-isoprene copolymer, methacrylic acid ester and conjugated diene copolymer, acrylonitrile-butadiene-styrene copolymer Examples thereof include a polymer, a styrene-isoprene-styrene block copolymer, a styrene-butadiene-styrene block copolymer, and an isobutene-isoprene copolymer (butyl rubber). These polymers may be emulsion-polymerized or solution-polymerized.

The specific polymer may have an ethylenically unsaturated group at the terminal or may have a partial structure represented by the following formula (A-1). In the following formula (A-1), R ¹ represents a hydrogen atom or a methyl group, A represents O or NH, and * represents a bonding position with another structure.

In formula (A-1), A is preferably O.
That is, the specific polymer may have a (meth) acryloyloxy group or a (meth) acrylamide group in the molecule, and more preferably has a (meth) acryloyloxy group.
The specific polymer may have a partial structure represented by the formula (A-1) at either the main chain terminal or the side chain, but preferably has the main chain terminal.
From the viewpoint of printing durability, the specific polymer preferably has two or more partial structures represented by the formula (A-1) in the molecule.

Specific polymers having a partial structure represented by the formula (A-1) include polybutadiene di (meth) acrylate, partially hydrogenated polybutadiene di (meth) acrylate, polyisoprene (meth) acrylate, and partially hydrogenated polyisoprene. Polyolefin (meth) acrylate obtained by reacting a hydroxyl group of a hydroxyl group-containing polyolefin such as (meth) acrylate with an ethylenically unsaturated group-containing compound (for example, BAC-45 (manufactured by Osaka Organic Chemical Industry Co., Ltd.), TEA-1000) , TE-2000, EMA-3000 (manufactured by Nippon Soda Co., Ltd.)).
In addition, modified polyolefins obtained by modifying polyolefins and introducing ethylenically unsaturated bonds (for example, methacrylate-introduced polyisoprene (Kuraprene UC-203, UC-102 (manufactured by Kuraray Co., Ltd.)) are also preferred.

(Polymer having monomer units derived from butadiene and / or isoprene)
The specific polymer is preferably a polymer having monomer units derived from butadiene and / or isoprene.
Specifically, polybutadiene (butadiene rubber), partially hydrogenated polybutadiene, terminal-modified polybutadiene, polyisoprene (isoprene rubber), partially hydrogenated polyisoprene, terminal-modified polyisoprene, SBR (styrene-butadiene rubber), SBS (styrene- Examples thereof include butadiene-styrene triblock copolymer), ABS (acrylonitrile-butadiene-styrene copolymer), SIS (styrene-isoprene-styrene triblock copolymer), and isoprene / butadiene copolymer.
The terminal modification means that the main chain or side chain terminal is modified with an amide group, a carboxy group, a hydroxy group, a (meth) acryloyl group, a glycidyl group, or the like.
Among these, polybutadiene, partially hydrogenated polybutadiene, hydroxyl-terminated polybutadiene, glycidyl ether-modified polybutadiene, polyisoprene, partially hydrogenated polyisoprene, terminal-modified polyisoprene, hydroxyl-terminated polyisoprene, glycidyl ether-modified polyisoprene, SBS, and SIS are preferable. .

  The proportion of monomer units derived from butadiene, isoprene or hydrogenated product thereof is preferably 30 mol% or more in total, more preferably 50 mol% or more, and further preferably 80 mol% or more. preferable.

Isoprene is known to polymerize by 1,2-, 3,4- or 1,4-addition, depending on the catalyst or reaction conditions, but may be polyisoprene polymerized by any of the additions described above. Among these, from the viewpoint of obtaining desired elasticity, it is preferable to contain cis-1,4-polyisoprene as a main component. In addition, when the specific polymer is polyisoprene, the content of cis-1,4-polyisoprene is preferably 50% by mass or more, more preferably 65% by mass or more, and 80% by mass or more. More preferably, it is particularly preferably 90% by mass or more.
As polyisoprene, natural rubber may be used, and commercially available polyisoprene can also be used. For example, the NIPOL IR series (manufactured by Nippon Zeon Co., Ltd.) is exemplified.

Butadiene is known to polymerize by 1,2- or 1,4-addition depending on the catalyst or reaction conditions, but may be polybutadiene polymerized by any of the additions described above in the present invention. Among these, it is more preferable that 1,4-polybutadiene is a main component from the viewpoint of obtaining desired elasticity.
When the specific polymer is polybutadiene, the content of 1,4-polybutadiene is preferably 50% by mass or more, more preferably 65% by mass or more, and further preferably 80% by mass or more. It is preferably 90% by mass or more.
In addition, although there is no restriction | limiting in particular in content of a cis body and a trans body, From a viewpoint of expressing rubber elasticity, a cis body is preferable and it is preferable that content of cis-1,4-polybutadiene is 50 mass% or more. , 65% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more.
As the polybutadiene, commercially available products may be used, and examples thereof include the NIPOL BR series (manufactured by Zeon Corporation) and the UBEPOL BR series (manufactured by Ube Industries).

(Specific polymer having monomer units derived from non-conjugated diene hydrocarbon)
The specific polymer may be a specific polymer having a monomer unit derived from a non-conjugated diene hydrocarbon.
Preferred examples of the specific polymer include a copolymer obtained by polymerizing a nonconjugated diene hydrocarbon and another unsaturated compound, preferably an α-olefinic unsaturated compound. The copolymer may be a random polymer, a block copolymer, or a graft polymer, and is not particularly limited.

Specific examples of the non-conjugated diene hydrocarbons include dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene, and ethylidene norbornene, and dicyclopentadiene and ethylidene norbornene are preferable. Ethylidene norbornene is more preferable. These compounds are used alone or in combination of two or more.
Specific examples of the monoolefin-based unsaturated compound include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-pentene, and the like. Ethylene and propylene are preferable, and a combination of ethylene and propylene is more preferable. These compounds are used alone or in combination of two or more.

  The polymer obtained by polymerizing the above conjugated diene hydrocarbon or the copolymer obtained by polymerizing the conjugated diene hydrocarbon and an α-olefin unsaturated compound is not particularly limited, but ethylene-α An olefin-diene copolymer is preferred, and ethylene-propylene-diene rubber (EPDM) is more preferred.

  Among the above, the specific polymer is preferably styrene-butadiene rubber, butadiene rubber, isoprene rubber, or ethylene-propylene-diene rubber, and more preferably butadiene rubber.

The specific polymer is preferably a polymer whose main chain mainly contains isoprene or butadiene as a monomer unit, and a part thereof may be hydrogenated to be converted to a saturated bond. In addition, the main chain or the terminal of the polymer may be modified with an amide, a carboxy group, a hydroxy group, a (meth) acryloyl group or the like, or may be epoxidized.
Among these, as the specific polymer, polybutadiene, polyisoprene, and isoprene / butadiene copolymer are preferably exemplified from the viewpoint of solubility in a solvent or handling, polybutadiene and polyisoprene are more preferable, and polybutadiene is further preferable.

The specific polymer preferably has a glass transition temperature Tg of 20 ° C. or less from the viewpoint of flexibility and rubber elasticity.
In addition, the glass transition temperature of a specific polymer is measured according to JIS K7121-1987 using a differential scanning calorimeter.
In addition, when a specific polymer has two or more glass transition temperatures, it is preferable that at least one is 20 degrees C or less, and it is more preferable that all the glass transition temperatures are 20 degrees C or less.

It is preferred that the specific polymer SP value is 14.0~18.0MPa ^1/2, more preferably 15.0~17.5MPa ^1/2, in 16.0～17.5MPa ^1/2 More preferably it is.
The SP value is the square root of the cohesive energy density of molecules, and represents the magnitude of the cohesive force between molecules, and is a measure of polarity.
It is preferable for the SP value to be in the above-mentioned range since moderate adhesiveness with a urethane adhesive can be obtained.
The above-mentioned SP value is calculated based on the Okitsu method described in Journal of the Japan Adhesion Society 29 (3) 1993, 204-211.

The specific polymer is preferably an elastomer or a plastomer. When the specific polymer is an elastomer or a plastomer, good thickness accuracy and dimensional accuracy can be achieved when the printing plate precursor for laser engraving obtained therefrom is formed into a sheet or cylinder. Moreover, since the elasticity required for a flexographic printing plate can be provided, it is preferable.
“Plastomer” refers to a shape that is easily fluidly deformed by heating and deformed by cooling, as described in “New Polymer Dictionary” edited by the Society of Polymer Science, Japan (Asakura Shoten, published in 1988). It means a polymer having the property that it can be solidified. Plastomer is a term for an elastomer (having the property of instantly deforming according to the external force when an external force is applied and restoring the original shape in a short time when the external force is removed). It does not show such elastic deformation and easily plastically deforms.
The plastomer means that when the original size is 100%, it can be deformed to 200% with a small external force at a room temperature of 20 ° C., and does not return to 130% or less even when the above external force is removed. The small external force specifically refers to an external force having a tensile strength of 1 to 100 MPa. More specifically, based on the tensile permanent strain test of JIS K 6262-1997, when the dumbbell-shaped No. 4 test piece defined in JIS K 6251-1993 is used, the above-mentioned test piece is obtained by a tensile test at 20 ° C. Can be stretched without breaking to twice the distance between the marked lines before pulling, and after holding for 60 minutes when the distance between the marked lines before tension is stretched to twice, excluding the tensile external force It means a polymer having a tensile set of 30% or more after 5 minutes. In the present invention, all of the test pieces are JIS K 6262 except that the test piece is dumbbell-shaped No. 4 defined in JIS K6251-1993, the holding time is 60 minutes, and the temperature of the test chamber is 20 ° C. -1997 tensile permanent strain test method.
In the case of a polymer that cannot be measured as described above, that is, in a tensile test, a polymer that does not return to its original shape even if a tensile external force is not applied, and a polymer that breaks by applying a small external force during the above measurement, Corresponds to plastomer.
Furthermore, the plastomer has a glass transition temperature Tg of the polymer of less than 20 ° C. In the case of a polymer having two or more glass transition temperatures Tg, all the glass transition temperatures Tg are less than 20 ° C. The glass transition temperature Tg of the polymer can be measured by a differential scanning calorimetry method.

The elastomer means a polymer that can be stretched to twice the distance between the marked lines in the above-described tensile test and has a tensile set of less than 30% after 5 minutes excluding the tensile external force.
The viscosity of the specific polymer at 20 ° C. is preferably 10 Pa · s to 10 kPa · s, more preferably 50 Pa · s to 5 kPa · s. When the viscosity is within the above range, the resin composition can be easily formed into a sheet and the process is simple. When the specific polymer is a plastomer, good thickness accuracy and dimensional accuracy can be achieved when the resin composition for forming a resin sheet is formed into a sheet shape.

A specific polymer may be used individually by 1 type, and may use 2 or more types together.
5-90 mass% is preferable with respect to the solid content total mass of a resin sheet, 15-85 mass% is more preferable, and, as for the total content of the specific polymer in the above-mentioned resin sheet, 30-80 mass% is still more preferable.
The total content of the specific polymer in the resin composition for forming a resin sheet is preferably 5 to 90% by mass, more preferably 15 to 85% by mass, and more preferably 30 to 85% by mass with respect to the total mass of the solid content of the resin composition. 80 mass% is still more preferable. By setting the content of the specific polymer to 5% by mass or more, printing durability sufficient to use the obtained cylindrical printing plate as a printing plate can be obtained, and by setting it to 90% by mass or less, other components Therefore, even when a cylindrical printing plate is used, flexibility sufficient for use as a printing plate can be obtained.
In addition, "solid content total mass" means the total mass remove | excluding volatile components, such as a solvent, from the resin sheet or the resin composition for resin sheet formation.

  The resin sheet and the resin composition for forming a resin sheet preferably contain a polymerization initiator, a photothermal conversion agent, a solvent, and other components. Hereinafter, these components will be described in detail.

(Polymerization initiator)
The resin composition for laser engraving is preferably formed using a resin composition for forming a resin sheet containing a polymerization initiator. By containing the polymerization initiator, crosslinking of the ethylenically unsaturated bonds contained in the specific polymer and the polymerizable compound described later is promoted.
As the polymerization initiator, those known to those skilled in the art can be used without limitation, and both a photopolymerization initiator and a thermal polymerization initiator can be used, but crosslinking can be formed with a simple apparatus. A thermal polymerization initiator is preferred. Hereinafter, although the radical polymerization initiator which is a preferable polymerization initiator is explained in full detail, this invention is not restrict | limited by these description.

  Preferred polymerization initiators include (a) aromatic ketones, (b) onium salt compounds, (c) organic peroxides, (d) thio compounds, (e) hexaarylbiimidazole compounds, (f) ketoximes. Examples include ester compounds, (g) borate compounds, (h) azinium compounds, (i) metallocene compounds, (j) active ester compounds, (k) compounds having a carbon halogen bond, (l) azo compounds, and the like. Specific examples of the above (a) to (l) are given below, but the present invention is not limited to these.

  When applied to engraving sensitivity and a resin sheet, (c) organic peroxides and (l) azo compounds are more preferable from the viewpoint of improving the small dot shape of the solid part and halftone dot part, c) Organic peroxides are particularly preferred.

(A) aromatic ketones, (b) onium salt compound, (d) thio compound, (e) hexaarylbiimidazole compound, (f) ketoxime ester compound, (g) borate compound, (h) azinium As the compound, (i) metallocene compound, (j) active ester compound, and (k) compound having a carbon halogen bond, the compounds listed in paragraphs 0074 to 0118 of JP-A-2008-63554 are preferably used. Can do.
In addition, (c) the organic peroxide and (l) the azo compound are preferably the following compounds.

(C) Organic peroxide Preferred as a thermal polymerization initiator (c) As the organic peroxide, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4 , 4′-tetra (t-amylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (t- Octylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (cumylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (p-isopropylcumylperoxycarbonyl) benzophenone, di- t-butyldiperoxyisophthalate, di-t-butyldiperoxyisophthalate, t-butylperoxybenzoate, t-butylperoxy-3 -Methylbenzoate, t-butylperoxylaurate, t-butylperoxypivalate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate, Peroxyesters such as t-butylperoxyneoheptanoate, t-butylperoxyneodecanoate, t-butylperoxyacetate, α, α'-di (t-butylperoxy) diisopropylbenzene, t Peroxyesters such as -butyl cumyl peroxide, di-t-butyl peroxide, t-butyl peroxyisopropyl monocarbonate, and t-butyl peroxy-2-ethylhexyl monocarbonate are preferred. Among these, t-butyl peroxybenzoate is particularly preferable from the viewpoint of excellent compatibility.

(L) Azo-based compound (l) Preferred azo-based compounds as polymerization initiators include 2,2′-azobisisobutyronitrile, 2,2′-azobispropionitrile, 1,1′-azobis ( Cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-) 2,4-dimethylvaleronitrile), 4,4′-azobis (4-cyanovaleric acid), dimethyl 2,2′-azobisisobutyrate, 2,2′-azobis (2-methylpropionamidooxime), 2,2 '-Azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide }, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2′-azobis (N-butyl-2-methylpropionamide), 2,2′-azobis ( N-cyclohexyl-2-methylpropionamide), 2,2′-azobis [N- (2-propenyl) -2-methylpropionamide], 2,2′-azobis (2,4,4-trimethylpentane), etc. Can be mentioned.

  In addition, the above-mentioned (c) organic peroxide is particularly preferable as a polymerization initiator from the viewpoint of improving the crosslinkability of the resin sheet and engraving sensitivity.

From the viewpoint of engraving sensitivity, an embodiment in which this (c) organic peroxide and a photothermal conversion agent described later are combined is particularly preferable.
This is because when an organic peroxide is used to cure a resin sheet by thermal crosslinking, an unreacted organic peroxide that does not participate in radical generation remains, but the remaining organic peroxide is a self-reactive addition. Works as an agent and decomposes exothermically during laser engraving. As a result, it is presumed that the engraving sensitivity is increased because the heat generated is added to the irradiated laser energy.
In addition, although explained in full detail in description of a photothermal conversion agent, this effect is remarkable when using carbon black as a photothermal conversion agent. This is because (c) heat generated from carbon black is also transferred to organic peroxide, so heat is generated not only from carbon black but also from organic peroxide. This is because energy generation occurs synergistically.

Only 1 type may be used for a polymerization initiator and it may use 2 or more types together.
The content of the polymerization initiator in the resin sheet is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass with respect to the total solid content, and 1 to 15%. % Is more preferable.
The content of the polymerization initiator in the resin composition for forming a resin sheet is preferably 0.01 to 30% by mass and more preferably 0.1 to 20% by mass with respect to the total solid content. Preferably, it is more preferable that it is 1 to 15%. It is preferable for the content to be in the above-mentioned range since the curability (crosslinking property) is excellent, the solid dot and halftone dot shapes are good when laser engraved, and the rinse property is excellent.

(Photothermal conversion agent)
It is preferable that the resin sheet and the resin composition for forming a resin sheet further contain a photothermal conversion agent. That is, it is considered that the photothermal conversion agent promotes thermal decomposition of the cured product during laser engraving by absorbing laser light and generating heat. For this reason, it is preferable to select a photothermal conversion agent that absorbs light having a laser wavelength used for engraving.

When the resin sheet is used for laser engraving using a laser emitting infrared rays of 700 to 1,300 nm such as YAG laser, semiconductor laser, fiber laser, and surface emitting laser as a light source, 700 to 1,300 nm is used as the photothermal conversion agent. It is preferable to use a compound having a maximum absorption wavelength.
Various dyes or pigments are used as the photothermal conversion agent.

  Among the photothermal conversion agents, as the dye, commercially available dyes and known ones described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specific examples include those having a maximum absorption wavelength at 700 to 1,300 nm, such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, diimmonium compounds, and quinoneimine dyes. Preferred are dyes such as methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes. Examples of dyes preferably used include cyanine dyes such as heptamethine cyanine dyes, oxonol dyes such as pentamethine oxonol dyes, phthalocyanine dyes, and dyes described in paragraphs 0124 to 0137 of JP-A-2008-63554. be able to.

Among the photothermal conversion agents, as pigments, commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, CMC Publishing, 1984) can be used. Examples of the pigment include pigments described in paragraphs 0122 to 0125 of JP-A-2009-178869.
Of these pigments, carbon black is preferred.

  As long as the dispersibility or the like in the composition is stable, carbon black can be used regardless of the application such as for color, rubber, dry battery, etc. in addition to the classification by ASTM. Carbon black includes, for example, furnace black, thermal black, channel black, lamp black, acetylene black and the like. The black colorant such as carbon black can be used as a color chip or color paste previously dispersed in nitrocellulose or a binder using a dispersant as required for easy dispersion. Such chips and pastes are readily available as commercial products. Examples of carbon black include those described in paragraphs 0130 to 0134 of JP2009-178869A.

As the photothermal conversion agent in the resin sheet and the resin composition for forming a resin sheet, only one type may be used, or two or more types may be used in combination.
The content of the photothermal conversion agent in the resin sheet varies greatly depending on the molecular extinction coefficient inherent to the molecule, but is preferably in the range of 0.01 to 30% by mass of the total solid content, 0.05 to 20% by mass. % Is more preferable, and 0.1 to 10% by mass is particularly preferable.
The content of the photothermal conversion agent in the resin composition for forming a resin sheet varies greatly depending on the molecular extinction coefficient inherent to the molecule, but is preferably in the range of 0.01 to 30% by mass of the total solid content. 0.05 to 20% by mass is more preferable, and 0.1 to 10% by mass is particularly preferable.

(solvent)
The resin composition for forming a resin sheet may contain a solvent.
As the solvent, an organic solvent is preferably used.
Preferred specific examples of the aprotic organic solvent include acetonitrile, tetrahydrofuran, dioxane, toluene, propylene glycol monomethyl ether acetate, methyl ethyl ketone, acetone, methyl isobutyl ketone, ethyl acetate, butyl acetate, ethyl lactate, N, N-dimethylacetamide, N -Methylpyrrolidone, dimethyl sulfoxide are mentioned.
Preferable specific examples of the protic organic solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 1-methoxy-2-propanol, ethylene glycol, diethylene glycol, and 1,3-propanediol.
Among these, propylene glycol monomethyl ether acetate is particularly preferable.

(Other additives)
The resin sheet and the resin composition for forming a resin sheet can be appropriately blended with various known additives as long as the effects of the present invention are not impaired. For example, a crosslinking agent, a crosslinking accelerator, a plasticizer, a filler, a wax, a process oil, a metal oxide, an antiozonation agent, an antiaging agent, a polymerization inhibitor, a coloring agent, and the like can be mentioned. Or two or more of them may be used in combination.

(Polymerizable compound)
The resin sheet can be formed by using a resin composition for forming a resin sheet containing a polymerizable compound in order to promote the formation of a crosslinked structure. By containing a polymerizable compound, formation of a crosslinked structure is promoted, and the resulting cylindrical printing plate is excellent in printing durability.
The specific polymer having an ethylenically unsaturated group described above is not included in the polymerizable compound.
Furthermore, the polymerizable compound is preferably a compound having a molecular weight of less than 3,000, and more preferably a compound having a molecular weight of less than 1,000.
The polymerizable compound is preferably a radical polymerizable compound, and is preferably an ethylenically unsaturated compound.

The polymerizable compound is preferably a polyfunctional ethylenically unsaturated compound. It is excellent in the printing durability of the cylindrical printing plate obtained as it is the above-mentioned aspect.
The polyfunctional ethylenically unsaturated compound is preferably a compound having 2 to 20 terminal ethylenically unsaturated groups. Such a compound group is widely known in this industrial field, and these can be used without particular limitation.
Examples of compounds derived from an ethylenically unsaturated group in the polyfunctional ethylenically unsaturated compound include, for example, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, and esters thereof And esters of unsaturated carboxylic acids and aliphatic polyhydric alcohol compounds, and amides of unsaturated carboxylic acids and aliphatic polyvalent amine compounds are preferably used. In addition, unsaturated carboxylic acid esters having nucleophilic substituents such as hydroxy groups and amino groups, amides and polyfunctional isocyanates, addition reaction products of epoxies, dehydration condensation reaction products of polyfunctional carboxylic acids Etc. are also preferably used. In addition, unsaturated carboxylic acid esters having an electrophilic substituent such as isocyanato group and epoxy group, amides and monofunctional or polyfunctional alcohols, addition reaction products of amines, halogen groups, or tosyloxy groups, etc. Also suitable are substitution reaction products of unsaturated carboxylic acid esters, amides with monofunctional or polyfunctional alcohols, and amines having the following leaving substituents. As another example, a compound group in which a vinyl compound, an allyl compound, an unsaturated phosphonic acid, styrene, or the like is substituted for the above-described unsaturated carboxylic acid can be used.

  The ethylenically unsaturated group contained in the polymerizable compound is preferably an acrylate, methacrylate, vinyl compound, or allyl compound residue from the viewpoint of reactivity. Further, from the viewpoint of printing durability, the polyfunctional ethylenically unsaturated compound preferably has 3 or more ethylenically unsaturated groups.

  Specific examples of the monomer of an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, 1, 3 -Butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, 1 , 4-Cyclohexanediol diacrylate, tetraethylene glycol diacrylate, polytetramethyl Glycol diacrylate, 1,8-octanediol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, tricyclodecane dimethanol diacrylate, trimethylolpropane triacrylate, trimethylolpropane triacrylate (Acryloyloxypropyl) ether, ditrimethylolpropane tetraacrylate, trimethylolethane triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, Sorbitol tetraacrylate, sorbitol pentaacrylate Sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, propylene glycol dimethacrylate, dipropylene glycol dimethacrylate, tripropylene glycol dimethacrylate, polypropylene Glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, 1,3-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,8-octanediol dimethacrylate, 1 , 9-Nonanediol dimethacryl 1,10-decanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p -(3-Methacryloxy-2-hydroxypropoxy) phenyl] dimethylmethane, bis [p- (methacryloxyethoxy) phenyl] dimethylmethane and the like. Of these, trimethylolpropane trimethacrylate and polyethylene glycol dimethacrylate are particularly preferable.

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate Sorbitol tetritaconate and the like.

  Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetracrotonate.

  Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.

  Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

Examples of other esters include aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, JP-A-59-5240, JP Those having an aromatic skeleton described in JP-A-59-5241 and JP-A-2-226149 or those containing an amino group described in JP-A-1-165613 are also preferably used.
The above ester monomers can also be used as a mixture.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bisacrylamide, methylene bismethacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. Examples include methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

  Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

  In addition, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable, and specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinyl urethane containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following general formula (i) to a polyisocyanate compound having two or more isocyanato groups. Compounds and the like.

_{CH 2 = C (R) COOCH} 2 CH (R ') OH (i)
However, R and R ′ each represent H or CH ₃ .

  Further, urethane acrylates described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B 58-49860, JP-B 56-17654, Urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 or JP-B-62-39418 are also suitable.

  Further, by using addition polymerizable compounds having an amino structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238, a short time can be obtained. A cured composition can be obtained.

  Other examples include reacting polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191 and JP-B-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as epoxy acrylates which have been made. Further, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, and vinyl phosphonic acid compounds described in JP-A-2-25493 are also included. be able to. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, the Japan Adhesion Association magazine vol. 20, no. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers, can also be used.

  Examples of the vinyl compound include butanediol-1,4-divinyl ether, ethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,3-propanediol divinyl ether, 1,3-butanediol divinyl ether, 1,4 -Butanediol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, trimethylol ethane trivinyl ether, hexanediol divinyl ether, tetraethylene glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, Sorbitol tetravinyl ether, sorbitol pentavinyl ether, ethylene glycol Diethylene vinyl ether, ethylene glycol dipropylene vinyl ether, trimethylolpropane triethylene vinyl ether, trimethylolpropane diethylene vinyl ether, pentaerythritol diethylene vinyl ether, pentaerythritol triethylene vinyl ether, pentaerythritol tetraethylene vinyl ether, 1,1,1-tris [4- ( 2-vinyloxyethoxy) phenyl] ethane, bisphenol A divinyloxyethyl ether, divinyl adipate and the like.

In the resin sheet and the resin composition used for forming the resin sheet, only one type of polymerizable compound may be used, or two or more types may be used in combination.
The content of the polymerizable compound in the resin sheet is preferably 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, and 1 to 10% by mass with respect to the total solid content of the resin composition. Further preferred.
The content of the polymerizable compound in the resin composition for forming a resin sheet is preferably 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, based on the total solid content of the resin composition. More preferably, it is 10 mass%. Within the above range, the rinsing property of engraving residue generated during laser engraving is excellent, and the printing durability of the obtained cylindrical printing plate is excellent.

(Amount of each component)
The total content of the specific polymer in the resin sheet is preferably 5 to 90% by mass, and the content of the polymerization initiator is preferably 0.01 to 30% by mass with respect to the total solid content of the resin sheet. The content of the photothermal conversion agent is preferably in the range of 0.01 to 30% by mass, and the content of the polymerizable compound is preferably 0 to 30% by mass.
The total content of the specific polymer in the resin composition for resin sheet formation is preferably 5 to 90% by mass relative to the total solid content of the resin composition for resin sheet formation, and the content of the polymerization initiator is It is preferable that it is 0.01-30 mass%, the range of 0.01-30 mass% is preferable, and, as for content of a photothermal conversion agent, 0-30 mass% is preferable.

(Resin sheet curing method)
Hereinafter, the resin sheet curing method will be described.
The resin sheet is preferably a sheet cured by the action of heat and / or light.
When the resin sheet contains a photopolymerization initiator, it can be cured by irradiation with light.
The light irradiation is preferably performed on the entire surface of the resin sheet.
Examples of light include visible light, ultraviolet light, and electron beam, but ultraviolet light is most preferable. If the support side of the resin sheet is the back side, the surface may only be irradiated with light. However, if the support is a transparent film that transmits light, it is preferable that the back side is further irradiated with light. When the protective film exists, the irradiation from the surface may be performed while the protective film is provided, or may be performed after the protective film is peeled off. When there is a possibility that the crosslinking reaction may be inhibited in the presence of oxygen, light irradiation may be performed after the resin sheet is covered with a vinyl chloride sheet and evacuated.
When the resin sheet contains a thermal polymerization initiator (the above-described photopolymerization initiator can also be a thermal polymerization initiator), it can be cured by heating the resin sheet (step of crosslinking by heat). ). Examples of the heating means for performing crosslinking by heat include a method of heating a resin sheet for a predetermined time in a hot air oven or a far-infrared oven, and a method of contacting a heated roll for a predetermined time.

As the above-mentioned resin sheet curing method, thermal crosslinking is preferable from the viewpoint that the resin sheet can be uniformly cured from the surface to the inside or can be crosslinked.
By cross-linking the resin sheet, first, the small dots of the solid part and the halftone dot part formed after laser engraving become sharp, and second, the adhesion of engraving residue generated during laser engraving is suppressed. There is an advantage.

Moreover, the manufacturing method of a flexographic printing plate may further include the following rinsing step, drying step, and / or post-crosslinking step, if necessary, following the engraving step.
Rinsing step: rinsing the engraved surface of the image forming layer after engraving with water or a liquid containing water as a main component.
Drying step: a step of drying the engraved image forming layer.
Post-crosslinking step: a step of imparting energy to the image forming layer after engraving to further cross-link the image forming layer.
Since the engraving residue is attached to the engraving surface after the engraving step, a rinsing step of rinsing the engraving residue by rinsing the engraving surface with water or a liquid containing water as a main component may be added. As a means of rinsing, a method of washing with tap water, a method of spraying high-pressure water, a known batch type or conveying type brush type washing machine as a photosensitive resin letterpress developing machine, the surface of the engraving is mainly present For example, when the engraving residue is not smooth, a rinsing liquid to which soap or a surfactant is added may be used.
When the rinsing process for rinsing the engraved surface is performed, it is preferable to add a drying process for drying the engraved recording layer and volatilizing the rinsing liquid.
Furthermore, if necessary, a post-crosslinking step for further crosslinking the engraved recording layer may be added. By performing the post-crosslinking step, which is an additional cross-linking step, it is possible to further strengthen the small dots of the solid portion and the halftone dot portion formed by engraving.

The pH of the rinsing liquid used in the rinsing step is preferably 9 or more, more preferably 10 or more, and still more preferably 11 or more. The pH of the rinsing liquid is preferably 14 or less, more preferably 13.5 or less, and still more preferably 13.1 or less. Handling is easy in the above-mentioned range. What is necessary is just to adjust pH using an acid and / or a base suitably in order to make a rinse liquid into the above-mentioned pH range, and the acid and base to be used are not specifically limited.
Moreover, it is preferable that a rinse liquid contains water as a main component. Further, the rinse liquid may contain a water-miscible solvent such as alcohols, acetone, and tetrahydrofuran as a solvent other than water.

It is preferable that the rinse liquid contains a surfactant. As surfactants, betaines such as carboxybetaine compounds, sulfobetaine compounds, phosphobetaine compounds, amine oxide compounds, or phosphine oxide compounds from the viewpoint of reducing engraving residue removal and the effect on flexographic printing plates. Preferred examples include compounds (amphoteric surfactants). Incidentally, N = O amine oxide compound, and, each structure of the P = O phosphine oxide ^{compounds, N + -O -, P +} -O - and the considered ones.
Examples of the surfactant include known anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. Furthermore, fluorine-based and silicone-based nonionic surfactants can be used in the same manner.
Surfactant may be used individually by 1 type, or may use 2 or more types together.
Although the usage-amount of surfactant does not need to specifically limit, it is preferable that it is 0.01-20 mass% with respect to the total mass of a rinse liquid, and it is more preferable that it is 0.05-10 mass%.

  The thickness of the image forming layer of the prepared flexographic printing plate is preferably 0.05 mm or more and 10 mm or less, and preferably 0.05 mm or more and 7 mm from the viewpoint of satisfying various printability such as abrasion resistance or ink transferability. The following is more preferable, and 0.05 mm or more and 3 mm or less is particularly preferable.

The Shore A hardness of the image forming layer of the prepared flexographic printing plate is preferably 50 ° or more and 90 ° or less. When the Shore A hardness of the image forming layer is 50 ° or more, even if the fine halftone dots formed by engraving are subjected to strong printing pressure of a relief printing press, they do not collapse and can be printed normally. In addition, when the Shore A hardness of the image forming layer is 90 ° or less, it is possible to prevent faint printing in a solid portion even in flexographic printing with a printing pressure of kiss touch.
The Shore A hardness in this specification is a durometer (spring type) in which an indenter (called a push needle or indenter) is pushed into the surface to be measured and deformed, and the amount of deformation (pushing depth) is measured and digitized. It is a value measured by a rubber hardness meter.

[Flexo printing equipment]
Next, the configuration of the flexographic printing apparatus using the flexographic printing plate will be described in detail. The flexographic printing apparatus basically has the same configuration as that of the conventional flexographic printing apparatus except that the flexographic printing plate described above is used.

FIG. 21 is a schematic diagram conceptually showing the structure of the flexographic printing apparatus.
A flexographic printing apparatus 90 shown in FIG. 21 prints using the flexographic printing plate 10 described above. The flexographic printing apparatus 90 includes a plate cylinder 91, an impression cylinder 92, an anilox roller 93, a doctor chamber 94, and a doctor blade 96.

The plate cylinder 91 is a cylindrical drum, and the flexographic printing plate 10 is attached to the peripheral surface, and the flexographic printing plate 10 is brought into contact with the printing medium Z while rotating.
The impression cylinder 92 is a roller that constitutes a conveyance unit (not shown) that conveys the printing medium Z along a predetermined conveyance path, and the circumferential surface thereof is arranged to face the circumferential surface of the plate cylinder 91. The printing medium Z is brought into contact with the flexographic printing plate 10.
The plate cylinder 91 is arranged so that the rotation direction thereof coincides with the conveyance direction of the printing medium Z.

  The anilox roller 93, the doctor chamber 94, and the doctor blade 96 are for supplying ink to the flexographic printing plate 10. The doctor chamber 94 is provided in close contact with the surface of the anilox roller 93 and retains ink therein. The doctor chamber 94 is supplied with ink by a circulation tank (not shown). The ink in the doctor chamber 94 is supplied to the surface of the anilox roller 93. The doctor blade 96 scrapes off unnecessary ink adhering to the surface of the anilox roller 93 and adjusts the ink amount. The anilox roller 93 abuts on the peripheral surface of the plate cylinder 91 and rotates synchronously to apply ink to the flexographic printing plate 10.

  The flexographic printing apparatus 90 configured as described above rotates the flexographic printing plate 10 placed on the plate cylinder 91 while transporting the printing medium Z along a predetermined transportation path, and causes ink to be printed on the printing medium Z. Transfer and print. That is, the rotation direction of the plate cylinder on which the flexographic printing plate 10 is mounted is the printing direction.

The type of the printing medium Z used in the flexographic printing apparatus 90 using the flexographic printing plate 10 is not particularly limited, and various known printing media used in ordinary flexographic printing apparatuses such as paper, film, and cardboard. The body can be used.
In addition, the type of ink used in the flexographic printing apparatus 90 using the flexographic printing plate 10 is not particularly limited, and a normal ink such as water-based ink, UV (ultra violet) ink, oil-based ink, or EB (electron beam) ink may be used. Various known inks used in flexographic printing apparatuses can be used.

  The present invention is basically configured as described above. As described above, the flexographic printing plate, the flexographic printing plate manufacturing method, and the flexographic printing plate manufacturing apparatus of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiment, and the scope of the present invention is not deviated. Of course, various improvements or modifications may be made.

  The features of the present invention will be described more specifically with reference to examples. The materials, usage amounts, substance amounts, ratios, processing details, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

In this example, based on the evaluation image, the flexographic printing plates of Examples 1 to 5 and Comparative Examples 1 and 2 were manufactured, the evaluation image was printed on the printing material, and the evaluation image of the printing material was visually observed. By evaluating, flexographic printing plates were evaluated.
In the flexographic printing plates of Examples 1 to 5 and Comparative Examples 1 and 2, the position of the first small point is set to 1/2 cell pitch from the solid portion outline, and the positions after the second small point are the first It is assumed that they are further arranged at a cell pitch interval from the position of the small point. That is, the position of the second small point was set to 3/2 cell pitch from the solid portion outline.

For the evaluation image, an image having a linear solid part and an image part corresponding to level 2 adjacent to the solid part was used. Data representing the evaluation image was used as original image data.
In the first to fifth embodiments, the first correction intensity function and the second correction intensity function obtained from the chart image having a plurality of highlight portions provided at level 1 intervals, and the above-described equation of Qc are used. A flexographic printing plate was manufactured using the corrected image data obtained by correcting the original image data.
In Examples 1 to 5, each parameter, “p”, “w (μm)”, and “v” in the above-described equation of Qc was set to the values shown in Table 1 below.
In Comparative Examples 1 and 2, a flexographic printing plate was produced using the above-described original image data without correction. For this reason, in Comparative Examples 1 and 2, “-” is written in the “p”, “w (μm)”, and “v” columns of Table 1 below.

<Preparation of flexographic printing plate>
As a flexographic printing plate precursor, a DLE-type flexographic plate FLEXEX FD-H (manufactured by FUJIFILM Corporation) was used. In Examples 1 to 5, corrected image data is used, and in Comparative Examples 1 and 2, the original image data is used under the conditions shown in Table 1 below. Laser engraving machine (FLENEX DLE Setter DL-50 (product name, Fuji Film) Engraved with a resolution of 2540 dpi, laser power (Depth power) 100%, dot shape profile: slope 60 °, and then a cleaning agent (2% joy aqueous solution manufactured by The Procter & Gamble Company) was dropped on the plate. The engraving residue was removed by rubbing with a pork brush and washing with running water to produce each flexographic printing plate.

(Printing process)
As the printing machine, MIRAFLEX AM (manufactured by Windmoller & Holscher) was used, and a sleeve made by ROSSINI was used as the plate cylinder.
Each flexographic printing plate was attached to a plate cylinder via a cushion tape (manufactured by Lohmann) and installed in a printing press. Thereafter, the kiss touch (printing pressure at which the entire image starts to fill) was set to 0 (reference printing pressure), and printing was performed at a printing speed of 150 m / min under the condition of 40 μm indentation.
An OPP (biaxially oriented polypropylene) film (manufactured by Abe Paper Co., Ltd.) having a thickness of 50 μm was used as the printing medium. As the ink, water-based flexographic ink, Hydrick FCF (manufactured by Dainichi Seika Co., Ltd.) was used.

(Evaluation)
The degree of halftone dots on a level 2 flat print in the evaluation image of the printing medium was visually evaluated according to the following evaluation criteria. The result of visual evaluation of the evaluation image is shown in the evaluation result column of Table 1 below. In the following evaluation criteria, evaluation B is an allowable limit.
Evaluation Criteria A The halftone dots in the center of the flat screen image area and the solid area are almost uniformly attached. B Although the size of the halftone dots in the center of the flat image area and the solid area is slightly different, there is no problem with the evaluation C. C It is clear that the halftone dot disappears in the vicinity of the solid or the density is lower than that in the central part, or unnaturalness is seen in the density change from the solid to the central part.

About the flexographic printing plates of Examples 1 to 5 and Comparative Examples 1 and 2, the small dots of the halftone dots were observed using an optical microscope, and the first small dots, the second small dots, and the third small dots were observed. The distance from the solid portion outline and the corrected dot size were obtained. The results are shown in Table 2 below.
Moreover, about the flexographic printing plates of Examples 1 to 5 and Comparative Examples 1 and 2, a part was cut and the cross section was observed using an optical microscope, and the first small point, the second small point, and the third small point were observed. The height of the dot was obtained. The heights of the first small point, the second small point, and the third small point are represented by a difference from the reference surface height Bh, and “the difference from the reference surface height Bh” in Table 2 below. The smaller the value in the column, the higher the height.
Since Comparative Examples 1 and 2 were not corrected, “*” was written in the numerical values in the “Pixel value after level 2 dot correction” column and the “Dot size after correction” column in Table 2 below. The “pixel value after correction of level 2 dots” in Table 2 below is a value obtained from the above-described equation of Qc.

As shown in Table 1, Examples 1 to 5 using the corrected image data are compared with Comparative Example 1 and Comparative Example 2 in which no corrected image data is created. The dot marking was good.
As shown in Table 2, in Examples 1 to 3 and Example 5, the heights of the first small point, the second small point, and the third small point are the first small point and the second small point. It is lower in the order of the dot and the third small dot. In Example 4, the second small point and the third small point had the same height, and had two types of small points.
On the other hand, since Comparative Examples 1 and 2 were not corrected, the heights of the first small point, the second small point, and the third small point were the same.
As described above, the flexographic printing plate of the present invention can be manufactured by the method of manufacturing a flexographic printing plate of the present invention. As described above, the flexographic printing plate of the present invention had good halftone dots in the center of the flat halftone image portion and in the vicinity of the solid.

DESCRIPTION OF SYMBOLS 10 Flexo printing plate 11 Non-image part 12, 68, 109, 114, 120 Image part 13, 69, 102, 122 Solid part 14, 104, 124 Halftone part 15, 104a Small point 15a First small point 15b Second Small point 15c third small point 15d fourth small point 15v small point 17 vertex 20 support 20b back surface 22 image forming layer 22a surface 24a, 24b, 24c, 24d pixel 30 manufacturing apparatus 32 acquisition unit 34 correction unit 36 network Point image data acquisition unit 38 Output image data acquisition unit 40 Processing unit 42 Memory 44 Control unit 46 Image data supply unit 50 Image information acquisition unit 52 Correction amount calculation unit 54 Correction calculation unit 60 Chart image 62 Solid image unit 64a, 64b, 64c , 64d, 64e, 64f Highlight portion 66 Image to be corrected 67 Pixel of interest 69a First edge 6 9b 2nd edge 70 Calendar roll 72a 1st roll 72b 2nd roll 72c 3rd roll 72d 4th roll 80 Kneaded material 81 Resin sheet 90 Flexographic printing apparatus 91 Plate cylinder 92 Impression cylinder 93 Anilox roller 94 Doctor chamber 96 Doctor blade 100 Flexographic printing plate 102b Outer edge 106, 110 Image 108 Solid frame 112 Image solid part 112b Inner peripheral edge Bh Reference surface height Dh Halftone dot height Dv Height E Contour fp First correction strength function fw Second correction strength function L ₁ 1st difference L ₂ 2nd difference L ₃ 3rd difference L ₄ 4th difference Ld difference RD range S10, S12, S14, S16, S18, S20, S30, S32, S34, S36 Step t Plate thickness Z Substrate

Claims (7)

A flexographic printing plate having an image portion and a non-image portion,
The image portion includes a solid portion that is a region having a predetermined area ratio or more, and a halftone dot portion having a small dot,
The dot of the halftone dot portion includes a first dot and a second dot,
The first small point is at a position closest to the outline of the solid portion,
The second small point is located farther from the contour than the first small point,
The solid portion has a reference surface height,
The first small point is equal to the reference surface height of the solid portion, or has a _first difference L1 from the reference surface height to the vertex of the first small point,
It said second small dot has a second difference L ₂ to the vertex of the second small point from the reference plane height,
It said first difference _{L 1} and the second difference _{L 2 are} flexographic printing plate, which is a L 1 _{<L 2.} The small dot of the average height of the halftone dot portion located farther from the contour than the second small point has a difference Ld from the reference surface height to the vertex of the small point. The flexographic printing plate according to claim 1, wherein the second difference L ₂ and the difference Ld satisfy L ₂ ≦ Ld.   3. The flexographic printing plate according to claim 1, wherein the first small point and the second small point exist within a range of 2 mm from the outline of the solid portion. A method for producing a flexographic printing plate having a non-image part and an image part,
Acquiring original image data of an image to be printed;
Correcting the original image data to obtain corrected image data;
Obtaining halftone image data from the corrected image data;
Obtaining output image data for processing a flexographic printing plate precursor based on the halftone dot image data;
A step of processing the flexographic printing plate precursor based on the output image data,
The step of obtaining the corrected image data includes a first correction intensity function whose value monotonously decreases with respect to the pixels of the original image data, and a predetermined area in the original image data. A method for manufacturing a flexographic printing plate, wherein the correction of the original image data is corrected by using a second correction strength function whose value monotonously decreases as the distance from the solid image portion, which is an area equal to or greater than the ratio, increases. . The first correction strength function and the second correction strength function are:
The solid image portion obtained by printing the plate making having a solid portion and a plurality of flat mesh image portions having different level values, and the plurality of flat mesh images having different level values obtained from the solid portion. Using the chart image with the highlight part obtained in the part,
5. The flexo according to claim 4, wherein image information of the solid image portion and the highlight portion of the chart image is acquired, and the first correction intensity function and the second correction intensity function are obtained based on the image information. A method for producing a printing plate. An apparatus for producing a flexographic printing plate having a non-image part and an image part,
An acquisition unit for acquiring original image data of an image to be printed;
A correction unit that corrects the original image data to obtain corrected image data;
A halftone image data acquisition unit for obtaining halftone image data from the corrected image data;
An output image data acquisition unit for obtaining output image data for processing a flexographic printing plate precursor based on the halftone dot image data;
A processing unit for processing the flexographic printing plate precursor based on the output image data;
The correction unit has a first correction intensity function whose value monotonously decreases as the level value of the pixel increases with respect to the pixel of the original image data, and a region having a predetermined area ratio or more in the original image data An apparatus for manufacturing a flexographic printing plate, wherein the correction of the original image data is corrected using a second correction intensity function whose value monotonously decreases as the distance from the solid image portion increases. The solid image portion obtained by printing the plate making having a solid portion and a plurality of flat mesh image portions having different level values, and the plurality of flat mesh images having different level values obtained from the solid portion. An image information acquisition unit that acquires image information of the solid image unit and the highlight unit for a chart image having a highlight unit obtained by the unit;
A correction amount calculation unit for obtaining the first correction strength function and the second correction strength function based on the image information;
The flexographic printing plate manufacturing apparatus according to claim 6, further comprising: a correction calculation unit that corrects a pixel value of the original image data using the first correction intensity function and the second correction intensity function.