WO2024214783A1 - Printing plate and method for manufacturing same - Google Patents

Abstract

In order to provide a printing plate in which film thickness unevenness in a body to be printed is less noticeable and a method for manufacturing the printing plate, this printing plate P is provided with a printing projection part 2 in which a plurality of protrusions 3 are formed in a top surface, the protrusions 3 being formed by transmission of light through a predetermined shape portion of a negative film to cure a photosensitive resin in portions where light is incident, and the predetermined shape being a shape (E) in which two or more halftone dot patterns are superimposed on the same plane such that at least one of the points of a halftone dot pattern overlaps at least one of the points of a different halftone dot pattern.

Description

Printing plate and its manufacturing method

The present invention relates to a printing plate used in printing such as flexographic printing and a method for manufacturing the same.

The liquid crystal panel includes an array substrate, a color filter substrate disposed opposite the array substrate, and a liquid crystal layer sandwiched therebetween. The array substrate includes, for example, a transparent substrate, a gate electrode, a gate insulating film, a semiconductor layer, a first protective film, a source electrode, a drain electrode, a second protective film, and a resin film.
A contact hole is formed in such an array substrate, and the transparent electrode is electrically connected to the drain electrode at the bottom of the contact hole.

Here, an alignment film made of polyimide or the like is formed on the entire surface of the transparent electrodes of the array substrate so as to fill the contact holes. Methods for forming an alignment film by applying an alignment film material such as polyimide onto the transparent electrodes of the array substrate include printing methods such as flexography and inkjet methods.

As shown in a plan view in Fig. 8(a) and in a T-T cross-sectional view in Fig. 8(b) of Fig. 8(a), a printing plate P1 used in flexographic printing typically comprises a flat base 11 and a printing convex portion 12 formed in the center of the surface of the base 11. The printing convex portion 12 is the printing area, and the portion of the base 11 around the printing convex portion 12 does not participate in printing.
8(c), which is an enlarged cross-sectional view of a main portion of Fig. 8(b), gaps 14 are distributed between a plurality of protrusions 13 on the top surface of the printing convex portion 12, and ink is retained in the gaps 14. The printing plate P1 has flexibility so that it can be mounted along the peripheral side surface of the plate cylinder 51 (see Fig. 7).

Fig. 9(a) is a perspective view showing a part of the protrusions 13 formed in the printing convex portion 12 of the general printing plate P1. Fig. 9(b) is a graph showing the height difference formed in the printing convex portion 12 by the protrusions 13 and the gaps 14 when the printing convex portion 12 is viewed in a side cross-sectional view. As shown in these figures, the multiple protrusions 13 are arranged orthogonally in the printing convex portion 12. Moreover, the protrusions 13 shown in Fig. 9(a) are minute, and as an example, 400 protrusions per inch (160,000 protrusions per square inch) are formed in the printing convex portion 12, and the depth of the gaps 14 between the protrusions 13 (depth from the height of the top surface of the protrusions 13 as a reference, the same applies below) is 15.8 μm. Moreover, the cell volume (representing the capacity that can hold ink) of the printing plate P1 on which the protrusions 13 are formed is 3.49 cm ³ /cm ² .

JP 2017-164979 A

When ink (alignment film material) is applied to the transparent electrodes of the array substrate by flexographic printing using the general printing plate P1 described above, the ink is retained in the gaps 14 formed between the multiple protrusions 13 arranged orthogonally, and the retained ink is transferred from the printing plate P1 in this state to the printing substrate Q (such as the array substrate) (see Figure 7).

When ink is transferred to the print medium Q in this manner, localized unevenness in thickness may occur in the alignment film. For example, around the contact holes formed in the array substrate, the ink may be repelled by surface tension or by fine debris (residue) created when the contact holes were formed, preventing the ink from fully penetrating the contact holes, resulting in uneven thickness of the alignment film around the contact holes and uneven thickness. When the liquid crystal panel is turned on (especially in mid-tones), the uneven thickness areas appear as uneven brightness and are easily visible.

6, the contact holes CH formed in the array substrate 20 are usually arranged regularly. As described above, the printing plate P1 also has a plurality of protrusions 13 arranged regularly, and therefore the gaps 14 for holding ink are also arranged regularly. Therefore, the gaps 14 for holding ink abut against the contact holes CH and the gaps 14 for holding ink abut against the areas around the contact holes CH where ink repellency occurs are both regularly generated, resulting in regular unevenness in the thickness of the transferred ink, and therefore regular unevenness in the thickness of the alignment film.
If there is regularity in the positions where the thickness unevenness occurs, the thickness unevenness becomes easily noticeable, which tends to cause a deterioration in the display quality of a liquid crystal panel manufactured using such an array substrate.

The present invention has been developed in consideration of these circumstances, and provides a printing plate and a method for manufacturing the same that make uneven film thickness on the printing medium Q less noticeable.

In order to achieve the above object, the printing plate of the present invention is a printing plate having a printing convex portion on a top surface of which a plurality of protrusions are formed,
the protrusions are formed by placing a negative film having a predetermined shape on a photosensitive resin that will become a printing plate, and allowing light to pass through the predetermined shaped portion of the negative film and harden the photosensitive resin in the portion that is hit by the light;
The predetermined shape formed on the negative film is a shape (E) in which two or more halftone dot patterns are superimposed on the same plane such that at least one of the dots in one halftone dot pattern overlaps with at least one of the dots in a different halftone dot pattern.

The present invention also provides a method for producing a printing plate, the method comprising the steps of: preparing a negative film having a predetermined shape; placing the negative film on a photosensitive resin that will become a printing plate; and irradiating the photosensitive resin on which the negative film is placed with light through the negative film, thereby curing the photosensitive resin at a position where the light passes through the negative film,
The printing plate has a printing convex portion having a plurality of protrusions formed on a top surface thereof,
the negative film preparation step forms a shape (E) on the negative film in which two or more halftone dot patterns are superimposed on the same plane such that at least one of the dots of one halftone dot pattern overlaps with at least one of the dots of a different halftone dot pattern,
In the photosensitive resin hardening step, light passes through the shape (E) portion formed on the negative film to harden the photosensitive resin on which the light strikes, and the protrusions are formed by the hardened portions.

If there is regularity in the positions where the thickness unevenness of the alignment film occurs, the thickness unevenness is easily noticeable. In other words, if the regularity is lost, the thickness unevenness becomes less noticeable.
The present inventors have focused on this point and discovered that by suppressing the regular occurrence of the above-mentioned thickness unevenness, the thickness unevenness can be made less noticeable.

That is, in order to achieve the above object, the present invention provides the following [1] to [6].
[1]
A printing plate having a printing convex portion on a top surface of which a plurality of protrusions are formed,
the protrusions are formed by placing a negative film having a predetermined shape on a photosensitive resin that will become a printing plate, and allowing light to pass through the predetermined shaped portion of the negative film and harden the photosensitive resin in the portion that is hit by the light;
The printing plate is characterized in that the predetermined shape formed on the negative film is a shape (E) in which two or more halftone dot patterns are superimposed on the same plane such that at least one of the dots of one halftone dot pattern overlaps with at least one of the dots of a different halftone dot pattern.
[2]
The printing plate according to [1], wherein the top shape of the protrusions is the same as the shape (E) above.
[3]
The printing plate according to [1] or [2], wherein the halftone dot pattern is one in which the halftone dots are arranged at equal intervals in both the row and column directions.
[4]
The printing plate according to any one of [1] to [3], wherein the shape of (E) is a shape in which a base halftone dot pattern M and a halftone dot pattern M1 to be overlaid on the base are overlaid at different angles so as to satisfy the following formula (1).
0°<α ₁ <90°...(1)
In equation (1), α ₁ is the angle between an imaginary line M' connecting the centers of adjacent dots in the row direction in dot pattern M and an imaginary line M1' connecting the centers of adjacent dots in the row direction in dot pattern M1.
[5]
The printing plate according to [4] has a plurality of halftone dot patterns to be superimposed on the base, and when the intersection point RP is an intersection point of imaginary lines connecting the centers of adjacent halftone dots in the row direction in each halftone dot pattern, the imaginary line M' of the base halftone dot pattern passes through the intersection point RP, and the multiple imaginary lines of the halftone dot patterns to be superimposed on the base are angled differently from each other with respect to the imaginary line M' of the base halftone dot pattern.
[6]
A method for producing a printing plate, comprising the steps of: preparing a negative film having a predetermined shape; placing the negative film on a photosensitive resin that will become a printing plate; and irradiating the photosensitive resin on which the negative film is placed with light through the negative film, thereby curing the photosensitive resin at a position where the light passes through the negative film,
The printing plate has a printing convex portion having a plurality of protrusions formed on a top surface thereof,
the negative film preparation step forms a shape (E) on the negative film in which two or more halftone dot patterns are superimposed on the same plane such that at least one of the dots of one halftone dot pattern overlaps with at least one of the dots of a different halftone dot pattern,
A method for producing a printing plate, characterized in that in the photosensitive resin hardening step, light passes through the shape (E) portion formed on the negative film to harden the photosensitive resin exposed to the light, and the protrusions are formed by the hardened portions.
[7]
The method for producing a printing plate according to [6], wherein the halftone dot pattern has halftone dots arranged at equal intervals in both row and column directions.

The printing plate of the present invention has a top surface shape of the protrusions that is formed to be the same as the shape (E-shape) of two or more halftone dot patterns superimposed on the same plane such that at least one of the points of one halftone dot pattern overlaps with at least one of the points of a different halftone dot pattern. This breaks down the regularity of the protrusions and gaps, making it possible to suppress the occurrence of regular unevenness in the film thickness of the alignment film provided on the array substrate. As a result, the unevenness in the film thickness can be made less noticeable.

In particular, when the halftone dot pattern has halftone dots arranged at equal intervals in the row and column directions, the halftone dot pattern itself is easy to create, and the regularity of the protrusions and gaps can be more easily disrupted.

Furthermore, when the angle α1 between an imaginary line M' connecting the centers of adjacent dots in the row direction in the base dot pattern M and an imaginary line M1 _' connecting the centers of adjacent dots in the row direction in the dot pattern M1 to be superimposed on the base satisfies the following formula (1), the regularity of the protrusions and gaps can be more reliably disrupted.
0°<α ₁ <90°...(1)

If there are multiple halftone dot patterns to be overlaid on the base, and the intersection point RP is the imaginary line connecting the centers of adjacent halftone dots in the row direction in these halftone dot patterns, and the imaginary line M' of the base halftone dot pattern passes through the intersection point RP, and the multiple imaginary lines of the halftone dot patterns to be overlaid on the base are at different angles to the imaginary line M' of the base halftone dot pattern, the regularity of the protrusions and gaps can be more reliably and easily disrupted.

In addition, the method for manufacturing a printing plate of the present invention includes the steps of placing a negative film having the shape (E) below formed thereon on a photosensitive resin that will become the printing plate, and irradiating light onto the photosensitive resin on which the negative film is placed, and curing the photosensitive resin at the position where the light passes through the negative film.This makes it possible to make the top shape of the protrusions correspond to the shape (E) below, and to form a printing plate that is free of regularity in the protrusions and gaps.
(E) A shape in which two or more halftone dot patterns are superimposed on the same plane with their positions shifted from each other.

In particular, when the halftone dot pattern has halftone dots arranged at equal intervals in the row and column directions, the regularity of the protrusions and gaps can be broken down even more effectively.

1A is a plan view of a printing plate according to an embodiment of the present invention; FIG. 1B is an enlarged view of a main portion of the printing plate taken along the line R-R of FIG. 1A; and FIG. 1C is an enlarged cross-sectional view of a main portion of FIG. 1B. FIG. 1A is an oblique view showing a portion of a protrusion formed in a printing convex portion of a printing plate of the present invention, and FIG. 1B is a graph showing the height difference formed in the printing convex portion by the protrusion and the gap when the printing convex portion is viewed in side cross-section. FIG. 1 is a diagram showing an example of the (E) shape in the present invention. (a) shows an example of a halftone dot pattern showing an arrangement of halftone dots, and (b) shows the same halftone dot pattern and a halftone dot pattern in which the angle of the same halftone dot pattern in a planar view is changed by rotating around a reference point. FIG. 10E is a diagram for explaining an example of a procedure for creating a shape. FIG. 2 is an explanatory diagram showing an arrangement of contact holes formed in an array substrate. FIG. 1 is an explanatory diagram illustrating a printing press that uses printing plates. 1A is a plan view of a conventional printing plate, FIG. 1B is a cross-sectional view taken along line T-T of FIG. 1A, and FIG. 1C is an enlarged cross-sectional view of a main part of FIG. 1A is an oblique view showing a portion of a protrusion formed on a printing convex portion, and FIG. 1B is a graph showing the height difference formed on the printing convex portion by the protrusion and the gap when the printing convex portion is viewed in side cross-section. FIG. 1A is a diagram illustrating a negative film used in the manufacture of a printing plate of the present invention, and FIG. 1B is a diagram illustrating a method of manufacturing a printing plate using the negative film.

Next, an embodiment of the present invention will be described in detail with reference to the drawings.
However, the present invention is not limited to the embodiment described below.
In the present invention, the expression "P or more" (P is an arbitrary number) also includes the meaning that "larger than P is preferable."

FIG. 1(a) is a plan view showing one embodiment of a printing plate of the present invention, (b) is an enlarged view of the essential parts of the R-R cross section of (a), and (c) is an enlarged view of the essential parts of the cross section of (b).

The printing plate P according to one embodiment of the present invention comprises a flat base 1 that is rectangular in plan view, and a printing protrusion 2 that is rectangular in plan view formed in the center of the surface of the base 1, with a plurality of protrusions 3 and gaps 4 (see FIG. 2(a)) distributed on the top surface of the printing protrusion 2. The printing plate P is used for flexographic printing. The printing plate P is flexible so that it can be attached to the peripheral surface of the plate cylinder 51 of a printing press (see FIG. 7). The printing plate P is formed from a material such as photosensitive resin, rubber, etc.

The base 1, printing convex portion 2, and protrusions 3 are integrally formed. In this embodiment, the direction of the arrow along the long side of the printing convex portion 2, which is rectangular in plan view, is set as the printing direction. On the top surface of the printing convex portion 2, gaps 4 are distributed among the multiple protrusions 3, as shown below, and ink is held in the gaps 4.

That is, Figure 2(a) is an oblique view showing a part of a protrusion 3 formed on the printing convex portion 2, and Figure 2(b) is a graph showing the height difference formed in the printing convex portion 2 by the above-mentioned protrusion 3 and gap portion 4 when the printing convex portion 2 is viewed in side cross-section.
As shown in FIG. 1(c) and FIG. 2(b), the protrusions 3 and the gaps 4 are formed in the printing convex portion 2 in a non-regular manner.
Furthermore, the gaps 4 formed between the protrusions 3 shown in FIG. 2(a) have, for example, a maximum depth of 15.7 μm and a cell volume of 3.69 ^cm3 / ^cm2 , which is approximately the same as that of a conventional printing plate in which multiple protrusions are regularly arranged.
It should be noted that the shapes of the printing convex portions 2 shown in Figs. 1(c), 2(a) and 2(b) are merely examples, and the shapes do not coincide with each other.

FIG. 3 is a diagram showing an example of the (E) shape in the present invention. The pattern RM shown in FIG. 3 is formed by using any number of halftone dot patterns, two or more (four in this example, see FIG. 5), and overlapping them on the same plane so that at least one of the dots in one halftone dot pattern overlaps with at least one of the dots in a different halftone dot pattern. In this case, the halftone dot patterns may be the same as each other, or may have different line numbers, etc. However, it is preferable to use patterns with different line numbers, etc., in order to further suppress the occurrence of moire.

The halftone dot pattern in the present invention may be any pattern in which the halftone dots are arranged with regularity, and the regularity may differ between the row and column directions. However, if the halftone dots are arranged at equal intervals in the row and column directions, the shape (E) with the regularity disrupted can be created more reliably by calculation.
Generally, the term "halftone dots" refers to dots arranged in a mesh pattern to express the shades of a printed matter, but in the present invention, the term is not limited to dots that express the shades of a printed matter, but refers to dots in general that are arranged in a mesh pattern with a predetermined regularity.

The above-mentioned shape (E) can be produced, for example, as follows.
Here, FIG. 4(a) shows a halftone dot pattern M showing an arrangement of halftone dots, and FIG. 4(b) shows the base halftone dot pattern M and halftone dot patterns M1 to M3 to be superimposed on the base.

4(b), it is preferable that the angle α1 between a virtual line M' connecting the centers (Mc) of adjacent dots in the row direction in the base dot pattern M and a virtual line M1' connecting the centers (M1c) of adjacent dots in the row direction in the dot pattern _M1 to be superimposed on the base satisfy the following formula (1), in order to further disrupt the regularity. When two or more dot patterns are used to be superimposed on the base, it is only necessary that the angle between each virtual line and the virtual line M' satisfy the following formula (1).
0°<α ₁ <90°...(1)

In particular, when there are multiple halftone dot patterns (e.g., halftone dot patterns M1, M2, M3, ...) to be superimposed on the base, and the intersection point RP is the imaginary line connecting the centers of adjacent halftone dots in the row direction (M1c, M2c, M3c, ...) in these halftone dot patterns, it is preferable that the imaginary line M' of the base halftone dot pattern passes through the intersection point RP and the multiple imaginary lines of the halftone dot patterns to be superimposed on the base are angled differently relative to the imaginary line M' of the base halftone dot pattern, as this can more reliably disrupt the regularity.
For example, when using a total of four halftone dot patterns, consisting of a base halftone dot pattern M and three halftone dot patterns (halftone dot patterns M1, M2, M3) to be superimposed on the base, it is preferable that the angles _α1 , _α2 , _α3 formed by these imaginary lines satisfy the relationship 0°< _α1 < _α2 < _α3 <90°, and it is even more preferable that the angles are separated by 10° or more.

The pattern RM shown in Figure 3 is a superposition of the halftone dot patterns M, M1 to M3, which have different specifications, as shown in Figure 5. Pattern RM is drawn and made into a negative, and a negative film (mask) for forming a printing plate is created using the negative-positive principle.

In this way, by overlapping the halftone dot patterns M, M1 to M3, a pattern RM with disrupted regularity is formed. Here, an example is shown in which the pattern RM is formed using four halftone dot patterns M, M1 to M3, but the pattern RM can be formed using two or more halftone dot patterns and is not limited to four halftone dot patterns. By changing the angle at which the multiple halftone dot patterns are overlapped, the shape of the pattern RM formed by overlapping multiple halftone dot patterns can be made infinite, but it is preferable to select a combination that generates as little unusual unevenness as possible.

However, in order to reliably avoid interference with the regularity of the arrangement of the contact holes CH formed in the array substrate 20 and suppress the occurrence of regular film thickness unevenness, it is preferable to use a pattern RM in which four or more halftone dot patterns are superimposed.

A method for manufacturing the printing plate P can be, for example, a photolithography method including the steps of preparing a negative film on which the pattern RM (E-shape) with disrupted regularity is formed, placing the negative film on a photosensitive resin that will become the printing plate P, and irradiating the photosensitive resin on which the negative film is placed with light through the negative film to harden the photosensitive resin at the position where the light passes through the negative film.
If the negative film preparation step involves forming a shape (E) on the negative film by overlapping two or more halftone dot patterns on the same plane such that at least one of the dots of one halftone dot pattern overlaps at least one of the dots of a different halftone dot pattern, then in the photosensitive resin hardening step, the portions of the photosensitive resin that are hit by light passing through the portions of shape (E) formed on the negative film become the protrusions 3. Moreover, the portions of the photosensitive resin that are not hit by light because light does not pass through the negative film become the gaps 4.

10(a) and (b) are diagrams for explaining a method for producing the printing plate P by photolithography.
First, as shown in Fig. 10(a), a negative film is prepared in which two or more halftone dot patterns are superimposed on the same plane such that at least one of the dots of one halftone dot pattern overlaps at least one of the dots of a different halftone dot pattern, forming a shape (E) as a light transmitting portion. Note that in Figs. 10(a) and 10(b), the light transmitting portions of the negative film are shown as white.
10(b), the photosensitive resin 6 on which the negative film 5 is placed is placed between the workpiece stage glass 8 and the workpiece glass cover 7, and light is irradiated in the direction indicated by the arrow. The irradiated light passes through the workpiece stage glass 8 and the shape (E), and the photosensitive resin 6 is partially cured by the transmitted light.
Then, by washing and removing all but the hardened portions of the photosensitive resin 6, the protrusions 3 and gaps 4 are formed, and a printing plate P can be manufactured in which the shape of the top surfaces 3a of the protrusions 3 is the same as the shape (E) described above (see Figure 2 (a)).

The obtained printing plate P is suitable for use as a printing plate for flexographic printing. Figure 7 shows an example of a flexographic printing press. This press is equipped with a cylindrical plate cylinder 51 on which the printing plate P is mounted, an anilox roll 52 that applies ink to the printing plate P, an ink supply device 53 that supplies ink to the surface of the anilox roll 52, a doctor blade 54 that scrapes off excess ink from the surface of the anilox roll 52, and a printing stage 55 on which the printing medium Q to be printed is placed.

Flexographic printing with the above printing press is performed as follows. That is, printing plate P is attached to the peripheral surface of plate cylinder 51, and while the plate cylinder 51 is rotating, ink supplied from ink supply device 53 is applied to the printing area of printing plate P via anilox roll 52, and the applied ink is transferred to a printing material Q such as a glass substrate placed on printing stage 55, thereby printing. At this time, printing stage 55 is slid in the direction of the arrow in synchronization with the rotation of plate cylinder 51.

As shown in FIG. 1(c), the printing plate P has gaps 4 distributed among the multiple protrusions 3 on the top surface of the printing convex portion 2, and ink is held in the gaps 4.

When ink is transferred to the substrate Q in this manner, typically when the substrate Q is an array substrate 20, the ink is repelled around the contact holes CH due to surface tension and fine debris (residue) generated during the formation of the contact holes, and the ink does not fully penetrate into the contact holes CH, resulting in an uneven ink film thickness around the contact holes CH and an uneven film thickness in the resulting alignment film.

However, since the protrusions 3 and gaps 4 are formed in a disordered manner on the printing convex portion 2 of the printing plate P of the present invention, even if the contact holes CH are formed in a regular arrangement on the array substrate 20, unevenness in the thickness of the alignment film will not occur regularly, and even if unevenness in the thickness does occur, it will be difficult to notice.

In this way, by using flexographic printing with the printing plate P of the present invention, it is possible to form an alignment film on an array substrate used in a liquid crystal panel while suppressing the occurrence of regular unevenness in film thickness.

The above examples show specific embodiments of the present invention, but the examples are merely illustrative and should not be interpreted as limiting. Various modifications that are obvious to those skilled in the art are intended to be within the scope of the present invention.

The printing plate of the present invention can be useful as a printing plate in which unevenness in film thickness is less noticeable.

P: printing plate 2: printing convex portion 3: projection 3a: top surface of projection 4: gap portion

Claims (7)

A printing plate having a printing convex portion on a top surface of which a plurality of protrusions are formed,
the protrusions are formed by placing a negative film having a predetermined shape on a photosensitive resin that will become a printing plate, and allowing light to pass through the predetermined shaped portion of the negative film and harden the photosensitive resin in the portion that is hit by the light;
The printing plate is characterized in that the predetermined shape formed on the negative film is a shape (E) in which two or more halftone dot patterns are superimposed on the same plane such that at least one of the dots of one halftone dot pattern overlaps with at least one of the dots of a different halftone dot pattern. The printing plate of claim 1, wherein the top surface shape of the protrusion is the same as the shape (E). The printing plate according to claim 1 or 2, wherein the halftone dot pattern has halftone dots arranged at equal intervals in the row and column directions. The printing plate according to any one of claims 1 to 3, wherein the shape of (E) is a shape in which a base halftone dot pattern M and a halftone dot pattern M1 to be overlaid on the base are overlaid at different angles so as to satisfy the following formula (1):
0°<α ₁ <90°...(1)
In equation (1), α ₁ is the angle between an imaginary line M' connecting the centers of adjacent dots in the row direction in dot pattern M and an imaginary line M1' connecting the centers of adjacent dots in the row direction in dot pattern M1. The printing plate according to claim 4, which has a plurality of halftone dot patterns to be superimposed on the base, and when the intersection point RP is an imaginary line connecting the centers of adjacent halftone dots in the row direction in each halftone dot pattern, the imaginary line M' of the base halftone dot pattern passes through the intersection point RP, and the plurality of imaginary lines of the halftone dot patterns to be superimposed on the base are at different angles to each other with respect to the imaginary line M' of the base halftone dot pattern. A method for producing a printing plate, comprising the steps of: preparing a negative film having a predetermined shape; placing the negative film on a photosensitive resin that will become a printing plate; and irradiating the photosensitive resin on which the negative film is placed with light through the negative film, thereby curing the photosensitive resin at a position where the light passes through the negative film,
The printing plate has a printing convex portion having a plurality of protrusions formed on a top surface thereof,
the negative film preparation step forms a shape (E) on the negative film in which two or more halftone dot patterns are superimposed on the same plane such that at least one of the dots of one halftone dot pattern overlaps with at least one of the dots of a different halftone dot pattern,
A method for producing a printing plate, characterized in that in the photosensitive resin hardening step, light passes through the shape (E) portion formed on the negative film to harden the photosensitive resin exposed to the light, and the protrusions are formed by the hardened portions. The method for manufacturing a printing plate according to claim 6, wherein the halftone dot pattern has halftone dots arranged at equal intervals in the row and column directions.

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