Flexographic printing plate

Abstract

In order to provide a flexographic printing plate capable of ensuring the uniformity of the thickness of a printing film up to the periphery of a printing region, a flexographic printing plate (P) is configured such that the shape of a plurality of protrusions in plan view is formed into a dot pattern. The dot pattern differs between a central region (2A) of the printing protrusion (2) and peripheral regions (2B, 2C) located at the peripheral edge of the central region (2A).

Description

Technical Field

[0001] The present invention relates to a printing plate for flexographic printing, and more specifically, to a flexographic printing plate capable of uniform printing up to the periphery. Background Technology

[0002] Flexographic printing generally uses methods such as Figure 14 The printing press shown is used. The printing press includes: a cylindrical printing plate roller 51 on which a flexible printing plate P1 is mounted; an anilox roller 52 on which ink is applied to the flexible printing plate P1; an ink supply device 53 for supplying ink to the surface of the anilox roller 52; a doctor blade 54 for scraping off excess ink from the surface of the anilox roller 52; and a printing table 55 on which the printable object Q is placed.

[0003] Furthermore, the flexographic printing performed by the printing press is carried out in the following manner: A flexographic printing plate P1 is mounted on the peripheral side of a printing plate roller 51. While rotating the printing plate roller 51, ink supplied from the ink supply device 53 is applied to the printing area of ​​the flexographic printing plate P1 via an anilox roller 52. This applied ink is then transferred to a substrate Q, such as a glass substrate, placed on a printing table 55, thereby performing printing (forming a printed film). During this process, the printing table 55 slides synchronously with the rotation of the printing plate roller 51.

[0004] Here, as Figure 15A As shown in the top view and as Figure 15B by Figure 15A As shown in the MM cross-sectional view, the flexible printing plate P1 generally includes a flat bottom 11 and a printing protrusion 12 formed in the center of the surface of the bottom 11. The printing protrusion 12 is the printing area, and the portion of the bottom 11 located around the printing protrusion 12 does not participate in printing.

[0005] In addition, such as Figure 15C To Figure 15B As shown in the enlarged cross-sectional view of the main part, on the top surface of the printing protrusion 12, a plurality of protrusions 13 are distributed and formed with respect to grooves 14, and ink is held in the grooves 14.

[0006] In addition, the flexible printing plate P1 is flexible enough to be mounted on the printing plate roller 51 (see reference). Figure 14 The circumferential side of ).

[0007] However, in the flexographic printing process, since the printing protrusion 12 of the flexographic printing plate P1 comes into contact with the anilox roller 52 and the substrate Q, the ink held on the printing protrusion 12 will concentrate in the peripheral area (e.g., peripheral area 12B) due to the pressure during this contact. Therefore, for the thickness of the printed film formed by the flexographic printing, sometimes the peripheral portion surrounding the central portion will be thicker than the central portion, resulting in a so-called "marginal phenomenon".

[0008] Therefore, various proposals have been made to suppress edge phenomena. For example, Patent Documents 1 and 2 propose a flexible printing plate in which the distribution density of the protrusions 13 formed on the printing protrusions 12 is set such that the peripheral region 12B of the printing protrusions 12 is higher than the central region 12A. That is, in the flexible printing plate described in Patent Documents 1 and 2, by making the distribution density of the protrusions 13 higher in the peripheral region 12B of the printing protrusions 12, and making the size of the grooves 14 formed between the protrusions 13 smaller, the amount of ink held in the grooves 14 is reduced, thereby suppressing the thickening of the peripheral portion of the printed film.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent No. 3376908

[0012] Patent Document 2: Japanese Patent Application Publication No. 2002-293049 Summary of the Invention

[0013] The problem the invention aims to solve

[0014] On the other hand, in flexographic printing, in addition to suppressing edge phenomena, various performance characteristics are required. For example, with the technological development of recent years, a high level of uniformity is required, and the uniformity of the printed film thickness must be ensured all the way to the periphery of the printed area.

[0015] The present invention was made in view of such circumstances, and provides a flexible printing plate that can ensure the uniformity of the printed film thickness up to the periphery of the printing area.

[0016] Solution for solving the problem

[0017] However, as the inventors conducted repeated and in-depth research in view of such a situation, they discovered that by forming the shape of the multiple protrusions formed on the top surface into a dot pattern when viewed from above, and by making the dot pattern different in the central region of the printing protrusion and in the peripheral region at the periphery of the central region, the straightness of the arrangement of the multiple protrusions at the ends formed in the peripheral region can be improved, and the positional shift of the printed film (orientation film) ends in order to cope with the narrow bezel of the liquid crystal panel can be suppressed.

[0018] That is, the present invention has the following aspects.

[0019] [1]

[0020] A flexible printing plate includes a plurality of printing protrusions formed on its top surface. The shape of the plurality of protrusions when viewed from above is formed as a dot pattern. The dot pattern differs between the central region of the printing protrusion and the peripheral region located at the periphery of the central region. The dot pattern differs between the printing direction portion and the right-angle direction portion in the peripheral region. The dot distribution density of the printing direction portion is set to be higher than that of the right-angle direction portion.

[0021] [2]

[0022] A flexible printing plate includes a printing protrusion having a plurality of protrusions formed on its top surface. The shape of the plurality of protrusions when viewed from above is formed as a halftone pattern. The halftone pattern differs between the central region of the printing protrusion and the peripheral region located at the periphery of the central region. The halftone pattern in the central region is an aggregate of halftone dots arranged in a column. The angle T formed by the imaginary line R connecting the centers of adjacent halftone dots arranged in the column and the printing direction S is set to 11°–34° or 56°–79°. The halftone pattern in the peripheral region is an aggregate of halftone dots arranged in a column. The angle T formed by the imaginary line R connecting the centers of adjacent halftone dots arranged in the column and the printing direction S is set to 0°±10° or 45°±10°.

[0023] [3]

[0024] According to the flexographic printing plate described in [2], among which,

[0025] In the dot pattern of the peripheral region, the spacing between adjacent dots arranged in the column is set to 20μm to 300μm.

[0026] [4]

[0027] According to any of the flexographic printing plates described in [1] to [3], among which,

[0028] The peripheral region has a printing direction portion along the printing direction and a right-angled direction portion along a right-angled direction perpendicular to the printing direction. The ratio (W / X) of the width W of the printing direction portion of the peripheral region to the width X of the printing protrusion is set to 0 < W / X < 0.05.

[0029] [5]

[0030] According to any of [2] to [4], the flexographic printing plate, wherein,

[0031] In the dot pattern of the peripheral region, the distances between adjacent dots arranged in the six surrounding directions are set to be equal.

[0032] Invention Effects

[0033] According to the flexible printing plate of the present invention, a plurality of protrusions are formed as a dot pattern in a top view, and the dot pattern is different in the central region of the printing protrusions from the peripheral region located at the periphery of the central region, thereby improving the straightness of the arrangement of protrusions at the ends formed in the peripheral region.

[0034] Therefore, by using this flexible printing plate, the thickness uniformity of the printed film can be ensured up to the periphery of the printing area, and it can be used in areas that were previously unusable due to uneven thickness of the printed film, thus enabling efficient production of printed films. Attached Figure Description

[0035] Figure 1 This is a top view schematically illustrating a flexible printing plate according to an embodiment of the present invention.

[0036] Figure 2 yes Figure 1 Enlarged view of the main part of the JJ cross section.

[0037] Figure 3 yes Figure 1 Enlarged view of the main part of the KK section.

[0038] Figure 4 yes Figure 1 Enlarged view of the main part of the peripheral area within the section enclosed by the dashed line L.

[0039] Figure 5 This is an explanation Figure 4 The diagram shows the case where the angle T between the imaginary line R and the direction of travel S is 0°.

[0040] Figure 6 yes Figure 1 Enlarged view of the main part of the central area within the section enclosed by the dashed line L.

[0041] Figure 7 This is an explanation Figure 6 The diagram showing the angle T between the imaginary line R and the direction of travel S.

[0042] Figure 8A This is a diagram illustrating the linear arrangement of the protrusions at the ends of the peripheral region when the angle T between the imaginary line R and the direction of travel S is 0°. Additionally, in Figure 8A Since the imaginary line R is parallel to the direction of travel S and cannot represent the angle T, the description of the angle T in the diagram is omitted.

[0043] Figure 8B It is a diagram illustrating the linear arrangement of the protrusions at the ends of the peripheral region when the angle T is -5°.

[0044] Figure 8C It is a diagram illustrating the linear arrangement of the protrusions at the ends of the peripheral region when the angle T is -10°.

[0045] Figure 9A It is a diagram illustrating the linear arrangement of the protrusions at the ends of the peripheral region when the angle T between the imaginary line R and the direction of travel S is 45°.

[0046] Figure 9B It is a diagram illustrating the linearity of the arrangement of protrusions at the ends of the peripheral region when the angle T is 40°.

[0047] Figure 9C It is a diagram illustrating the linear arrangement of the protrusions at the ends of the peripheral region when the angle T is 35°.

[0048] Figure 10A The image is an enlarged photograph of a portion of the flexible printing plate according to an embodiment of the present invention.

[0049] Figure 10B The image is an enlarged photograph of a portion of the flexographic printing plate of a comparative example of the present invention.

[0050] Figure 11A It is a diagram illustrating a dot pattern formed by dots arranged in rows in both the horizontal and vertical directions.

[0051] Figure 11B This diagram illustrates a dot pattern in which adjacent dots arranged in the six surrounding directions are spaced at equal distances from each other.

[0052] Figure 12 It is a diagram illustrating the difference in dot distribution density between the printing direction portion and the right-angle direction portion of the halftone pattern in the peripheral area.

[0053] Figure 13 This is to explain Figure 12 A diagram showing the depth of the grooves between multiple protrusions formed by the configuration of the dot pattern.

[0054] Figure 14 This is an illustrative diagram showing a printing press that uses flexographic printing plates.

[0055] Figure 15A This is a schematic top view of a traditional flexographic printing plate.

[0056] Figure 15B yes Figure 15A Enlarged view of the main part of the MM cross section.

[0057] Figure 15C yes Figure 15B Enlarged cross-sectional view of the main parts. Detailed Implementation

[0058] The present invention will now be described in more detail based on embodiments thereof, but the present invention is not limited to the following embodiments.

[0059] Furthermore, in this invention, when expressed as "Y~Z" (Y and Z are arbitrary numbers), unless otherwise specified, it means "above Y and below Z", and also includes "preferably, greater than Y" or "preferably, less than Z".

[0060] In addition, when expressed as "Y or above" (where Y is any number) or "Z or below" (where Z is any number), it also includes the meaning of "preferred to be greater than Y" or "preferred to be less than Z".

[0061] <<First Implementation>>

[0062] Figure 1 This is a top view schematically illustrating one embodiment of the flexible printing plate of the present invention. Figure 2 yes Figure 1 Enlarged view of the main part of the JJ cross-section. Figure 3 yes Figure 1 Enlarged view of the main part of the KK section.

[0063] The flexible printing plate P of this embodiment includes: a rectangular flat bottom 1 in plan view and a rectangular printing protrusion 2 formed in the center of the surface of the bottom 1 in plan view. On the top surface of the printing protrusion 2, a plurality of tiny frustum-shaped protrusions 3 are distributed and formed with gaps (grooves 4) and ink is retained in the grooves 4. The bottom 1, the printing protrusion 2 and the protrusions 3 are integrally formed.

[0064] In addition, in this embodiment, the direction of the arrow along the long side of the printing protrusion 2, which is rectangular when viewed from above, is set as the printing direction (travel direction S).

[0065] The flexible printing plate P is used for flexible printing and is flexible enough to be mounted on a printing press (see reference). Figure 14 The circumferential side surface of the printing plate roller 51. Examples of materials used to form the flexible printing plate P include resin and rubber. Methods for forming the flexible printing plate P include, for example, die forming; when using a photosensitive resin as the forming material, photolithography is preferred.

[0066] Furthermore, the dimensions of the frustum-shaped protrusion 3 can be, for example, such that the diameter of the top surface is set in the range of 20 μm to 70 μm, the diameter of the bottom surface is set in the range of 185% to 300% of the diameter of the top surface, and the depth D from the top surface to the bottom of the groove 4 is set in the range of 5 μm to 25 μm (see reference). Figure 2 ).

[0067] Furthermore, the distribution density of the protrusions 3, for example, if expressed as the number of protrusions 3 per inch (25.4 mm), can be set in the range of 100 to 1300.

[0068] The printing protrusion 2 is roughly divided into two regions (parts). That is, according to the distribution of the protrusions 3, it is divided into a central region 2A and peripheral regions 2B and 2C located at the periphery of the central region 2A. In the central region 2A and the peripheral regions 2B and 2C, the dot patterns (hereinafter sometimes referred to as "dot patterns") that are identified as the top view shape of the protrusions 3 are different from each other.

[0069] Here, the dots identified as the top view shape of the protrusion 3 refer to the top surface, not the bottom surface. This is to be consistent with the fact that the aperture ratio is usually calculated based on the area of ​​the top surface of the protrusion 3.

[0070] <Peripheral areas 2B, 2C>

[0071] First, the peripheral regions 2B and 2C of the printing protrusion 2 will be explained.

[0072] Figure 4 Explanation in Figure 1 The dot pattern formed by multiple protrusions 3 in the peripheral areas 2B and 2C of the part surrounded by the dotted line L, when viewed from above.

[0073] In this embodiment, the dot patterns in the peripheral regions 2B and 2C are the same. The dot patterns are formed by a collection of dot patterns 3a arranged in a column, and the angle T formed by the imaginary line R connecting the centers 3b of the adjacent dot patterns 3a arranged in the column and the printing direction S is set to 0°.

[0074] In addition, Figure 4The dot pattern of the protrusions 3 formed in the central region 2A is omitted from the illustration. Furthermore, since the imaginary line R is parallel to the direction of travel S and does not intersect with it, angle T is not shown.

[0075] In the dot pattern, for the imaginary line connecting the centers 3b of adjacent dots 3a arranged in a column, there exists not only Figure 4 The imaginary line R shown also exists as... Figure 5 The imaginary line r1 shown connects the centers 3b of adjacent dots 3a in the vertical direction (the vertical direction on the paper).

[0076] In addition, there is also an imaginary line r2 that connects the center 3b of adjacent dots 3a in the tilt direction (the upper left direction of the paper).

[0077] However, as Figure 11A As shown, in the dot pattern, regarding the distance between the centers 3b of adjacent dots 3a, the distance between adjacent dots 3a in the inclined direction (distance E2) is longer than the distance between adjacent dots 3a in the longitudinal and transverse directions (distance E1). Therefore, the selection of dots 3a for obtaining the imaginary line R is as follows: Figure 5 The halftone dots 3a that are adjacent in the horizontal and vertical directions are shown, but the halftone dots 3a that are adjacent in the diagonal direction are not selected (although not shown, the same applies to the halftone dots 3a that are adjacent in the upper right direction on the paper).

[0078] In this invention, when multiple imaginary lines can be drawn, imaginary lines whose angle with the direction of travel is 0° or more and less than 90° are designated as imaginary lines of this invention.

[0079] Therefore, as Figure 5 As shown, in the dot pattern, the angle T between the imaginary line r1 and the direction of travel S is 90°, therefore it is not used. Furthermore, as mentioned above, the imaginary line r2 is not used because the distance between adjacent dots 3a is relatively long.

[0080] Thus, when the angle T between the imaginary line R of the halftone pattern in the peripheral regions 2B and 2C and the printing direction S is 0°, as... Figure 8A As shown in the portion surrounded by dashed lines, the straightness of the arrangement of the protrusions 3 formed at the very end of the printing protrusion 2 (to make the arrangement easier to observe, a line (imaginary line F) is drawn that contacts the outer side of the protrusion 3 (dot 3a), and the same applies below) is improved. Furthermore, in Figure 8A The description of angle T is omitted.

[0081] Furthermore, the same applies when the angle T is set to 0°±10° or 45°±10°, improving the linearity of the arrangement of the protrusions 3 at the outermost ends (see reference). Figure 8B , Figure 8C).

[0082] That is, when the angle T is -5°, as Figure 8B As shown in the section surrounded by the dashed line, the straightness of the arrangement of the protrusions 3 formed at the very end (imaginary line F) is slightly disordered (there are parts at the end where no protrusions 3 are formed), but it still has sufficient straightness.

[0083] Additionally, when the angle T is -10°, as Figure 8C As shown in the section surrounded by the dashed line, the straightness of the arrangement of the protrusions 3 formed at the very end (imaginary line F) is further disordered (there are parts at the end where no protrusions 3 are formed), but it still has an acceptable straightness.

[0084] in addition, Figure 8B and Figure 8C The pattern after angle T is shifted 5° or 10° in the - (negative) direction from 0°, and the pattern after shifting 5° or 10° in the + (positive) direction, also shows that the arrangement of the protrusions 3 at the very end has the same linearity.

[0085] On the other hand, such as Figure 9A As shown in the section enclosed by the dashed line, when the angle T is 45°, the straightness of the arrangement of the protrusions 3 at the outermost end (imaginary line F) is also improved. Furthermore, similarly to the case where the angle T is 0°, the straightness is also improved when the angle T is near 45°.

[0086] That is, when the angle T is 40°, as Figure 9B As shown in the section surrounded by the dashed line, the straightness of the arrangement of the protrusions 3 formed at the very end (imaginary line F) is slightly disordered (there are parts at the end where no protrusions 3 are formed), but it still has sufficient straightness.

[0087] Additionally, when the angle T is 35°, such as Figure 9C As shown in the section surrounded by the dashed line, the straightness of the arrangement of the protrusions 3 formed at the very end (imaginary line F) is further disordered (there are parts at the end where no protrusions 3 are formed), but it still has an acceptable straightness.

[0088] in addition, Figure 9B and Figure 9C The pattern after angle T is shifted 5° or 10° in the negative direction from 45°, and the pattern after shifting 5° or 10° in the positive direction, also shows that the arrangement of the protrusions 3 at the very end has the same linearity.

[0089] In addition, such as Figure 1As shown, the peripheral regions 2B and 2C include a peripheral region 2B along the printing direction and a peripheral region 2C along a right-angled direction perpendicular to the printing direction. The ratio (W / X) of the width W of the peripheral region 2B to the width X of the printing protrusion 2 is preferably 0 < W / X < 0.05.

[0090] Furthermore, the width W of the peripheral region 2B is preferably 0.1 mm or more and 1 mm or less. That is, in order to minimize the impact on the effective area, it is preferable to be narrower. On the other hand, in order to obtain the effect of improving straightness, it is necessary to arrange a certain number of dots in the peripheral region with a different dot pattern than that in the central region.

[0091] The width W of the peripheral region 2B is the sum of the widths W1 and W2 of the left and right edges relative to the printing direction (W1 + W2). The widths W1 and W2 may be the same or different.

[0092] If the width W is too small, the area of ​​the peripheral region 2B will be too small, and there is a tendency to make it difficult to form the desired dot pattern. If the width W is too large, the area of ​​the central region 2A will be too small. For example, when the printing object is an array substrate, even if a dot pattern is set to solve the problem of uneven ink thickness, there is a tendency to reduce the effect obtained.

[0093] Thus, when the ratio (W / X) is within the stated range, an excellent balance is achieved between the complexity of the dot pattern design and the effect obtained.

[0094] Furthermore, in the dot pattern of the peripheral regions 2B and 2C, the spacing between adjacent dots 3a arranged in the column is not particularly limited, but it is preferably set to 20μm to 300μm, and more preferably to 30μm to 90μm.

[0095] That is, the shorter the spacing, the more advantageous it is in terms of linearity. On the other hand, if the spacing is too short, the volume of the slot 4 cannot be guaranteed, and there is a tendency to not be able to retain the necessary amount of ink. However, when the spacing between adjacent dots 3a is set within the above range, the balance between linearity and ink retention is excellent.

[0096] In addition, such as Figure 4 , Figure 11A and Figure 11B As shown, the spacing between adjacent grid points 3a represents the shortest distance H between grid points 3a.

[0097] <Central Region>

[0098] Next, the central region 2A of the printing protrusion 2 will be described.

[0099] Figure 6 This means that in Figure 1 The dot pattern of protrusions 3 formed in the central region 2A of the portion surrounded by the dashed line L. In this embodiment, the angle T between the imaginary line R connecting the centers 3b of adjacent dots 3a arranged in a column and the printing direction S is set to 68°.

[0100] In addition, Figure 6 The dot pattern of the protrusions 3 formed in the peripheral regions 2B and 2C is omitted from the illustration.

[0101] Figure 7 Explanation in Figure 6 When multiple imaginary lines can be drawn in a dot pattern, the method of selecting the imaginary line R used in this invention is as follows. As described above, when multiple imaginary lines can be drawn, in this invention, imaginary lines whose angle T with the direction of travel is 0° or more and less than 90° are defined as imaginary lines of this invention. Therefore, in Figure 6 In the halftone pattern shown, the imaginary line r1, which is positioned at the upper right relative to the paper, is not used; instead, the imaginary line R, which is positioned at the upper left relative to the paper, is used. The reason for this is that, as... Figure 7 As shown, the angle t1 between the imaginary line r1 and the direction of travel S is 158° or the angle t2 is -22°. Furthermore, the imaginary line r2 was not used because the distance between adjacent grid points 3a is relatively long.

[0102] There is no particular limitation on the dot pattern of the central region 2A, but when the array substrate is used as the printed object, the angle T formed by the imaginary line R connecting the centers 3b of the adjacent dots 3a arranged in a row and the printing direction S is preferably 56° to 79°.

[0103] That is, around the contact holes formed on the array substrate of the liquid crystal panel, the ink transferred by flexible printing is sometimes repelled due to surface tension or fine debris (residue) generated during the formation of the contact holes, which prevents the ink from fully entering the contact holes. This causes the film thickness of the alignment film around the contact holes to become uneven, resulting in uneven film thickness.

[0104] Furthermore, the contact holes formed on the array substrate are typically arranged in regular rows. Therefore, when the ink-holding groove comes into contact with the area where ink repulsion occurs around the contact hole, the film thickness non-uniformity in that area becomes noticeable. If this noticeable film thickness non-uniformity occurs regularly, the film thickness non-uniformity becomes even more pronounced.

[0105] To address this issue, in the dot pattern of the central region 2A, the angle T between the imaginary line R connecting the centers 3b of adjacent dots 3a arranged in a column and the printing direction S is 56° to 79°. This is because, if this is the case, the ink grooves 4 are less likely to make regular contact with the contact holes formed on the array substrate, thus preventing the film thickness unevenness from becoming more pronounced.

[0106] Furthermore, when the angle T is between 11° and 34°, it is also possible to prevent the film thickness unevenness from becoming more pronounced, so it is preferred.

[0107] Thus, in the flexible printing plate P of the first embodiment, in the dot pattern of the peripheral regions 2B and 2C, the angle T formed by the imaginary line R connecting the centers 3b of the adjacent dots 3a arranged in the column and the printing direction S is set to 0°±10° or 45°±10°.

[0108] Therefore, the linearity of the protrusions 3 formed at the very end of the peripheral region 2B is improved, and the amount of ink in the grooves 4 formed between the protrusions 3 can be kept uniform up to the periphery of the peripheral region 2B.

[0109] Furthermore, if the angle T between the imaginary line R connecting the centers 3b of adjacent dots 3a arranged in the column and the printing direction S in the dot pattern of the central region 2A is set to 11° to 34° or 56° to 79°, then, for example, when the array substrate is the printed object, the unevenness of film thickness can be made less noticeable in most of the printing area.

[0110] Therefore, by using the flexible printing plate P, it is possible to form the alignment film in the liquid crystal display, the organic light-emitting film in the organic electroluminescent element, and the electrode film in the electronic device to each corner with improved thickness uniformity.

[0111] <<Second Implementation>>

[0112] like Figure 11B As shown, the second embodiment is to make the dot pattern of the peripheral regions 2B and 2C in the first embodiment (refer to...) Figure 11A () is formed by equidistant points 3a arranged in the six directions around it.

[0113] That is, such as Figure 11AAs shown, in the first embodiment, the distance between the centers 3b of adjacent dots 3a is longer in the diagonal direction (distance E2) than the distance between adjacent dots 3a in the longitudinal and transverse directions (distance E1) in terms of the distance between their centers 3b. Therefore, the dots 3a used to obtain the imaginary line R are selected from those adjacent in the longitudinal and transverse directions, and not those adjacent in the diagonal direction.

[0114] On the other hand, such as Figure 11B As shown, in the second embodiment, since the distance (distance E3) between adjacent dots 3a arranged in the six surrounding directions is equal, the difference in depth and length of the groove 4 can be minimized. If the difference in depth and length of the groove 4 is minimized, the difference in ink retention in each part is minimized, which can further improve the uniformity of the printed film thickness.

[0115] Furthermore, when the dot pattern is set such that adjacent dots 3a in the six surrounding directions are equidistant from each other, connecting the imaginary line R with dots in any of the vertical, horizontal, or diagonal directions as adjacent dots 3a yields the same result. Therefore, any dot 3a can be chosen to obtain the imaginary line R. Figure 11B In the diagram, the angle T between the imaginary line R and the direction of travel S is set to 55°.

[0116] When using a dot pattern in which adjacent dots 3a arranged in the six directions around the perimeter are equidistant from each other as the dot pattern in the peripheral regions 2B and 2C, the angle T between the imaginary line R and the direction of travel S is not particularly limited. However, if the angle T between the selected imaginary line R and the direction of travel S is set to any one of 0°±10°, 30°±10°, or 60°±10°, there is a tendency to further improve the straightness of the arrangement of the protrusions 3 formed at the very end of the peripheral region 2B.

[0117] <<Third Implementation Method>>

[0118] like Figure 12 As shown, the third embodiment is to make the dot pattern of the peripheral regions 2B and 2C in the first embodiment (refer to...) Figure 4 The distribution density of the dots 3a in the peripheral region 2C is set to be higher than that in the peripheral region 2B, so that the dot pattern is different in the peripheral region 2B and the peripheral region 2C.

[0119] As for the distribution density, examples include setting the distribution density of dots 3a in the peripheral region 2B to a range of 200 dots / inch to 400 dots / inch, and setting the distribution density of dots 3a in the peripheral region 2C to a range of 400 dots / inch to 600 dots / inch, which are higher than the distribution density of dots 3a in the peripheral region 2B.

[0120] Thus, by setting the dot density of the peripheral region 2C (right-angle direction portion) and the peripheral region 2B (printing direction portion) to be different from each other, under the pressure of the printing protrusion 2 contacting the anilox roller 52 of the printing press and the printed body Q, the ink held in the groove 4 of the printing protrusion 2 can easily diffuse into a more uniform thickness on the top surface of the printing protrusion 2.

[0121] In addition, the peripheral regions 2B (the printing direction portion along the printing direction) and 2C (the right-angled direction portion along the right-angled direction perpendicular to the printing direction) located at the periphery of the central region 2A overlap at four corners, and the portions of the four corners are included in the peripheral region 2C (the right-angled direction portion).

[0122] In addition, such as Figure 13 As shown, in this third embodiment, the depth D1 of the protrusion 3 in the peripheral region 2B (printing direction portion) measured from the surface is different from the depth D2 of the protrusion 3 in the peripheral region 2C (right angle portion) measured from the surface, and this depth is preferably set to D1 > D2.

[0123] As for the depth, examples include setting the depth D1 in the peripheral region 2B (printing direction portion) to a range of 15μm to 25μm, and setting the depth D2 in the peripheral region 2C (right-angle direction portion) to a value smaller than depth D1, ranging from 5μm to 15μm. By setting D2 to a smaller value, less ink can be retained in the groove 4, which tends to prevent the straightness of the printed film end from deteriorating due to excess ink diffusion during printing.

[0124] [Example]

[0125] Figure 10A It is obtained by enlarging and photographing a portion of a flexible printing plate P with the angle T set to 72° in the dot pattern of the central region 2A and the angle T set to 45° in the dot pattern of the peripheral region 2B.

[0126] For the flexible printing plate P, for example, when printing resin (ink) for forming an orientation film onto an array substrate, the unevenness of film thickness is less noticeable in the central region 2A, which occupies most of the surface of the printing protrusions 2 of the flexible printing plate P, and the regularity (straightness) of the arrangement of the protrusions at the outermost ends is improved in the peripheral region 2B (see reference). Figure 10A (the boundary between the peripheral region 2B and the bottom 1), thus ensuring that the amount of ink in the groove 4 formed between the protrusions 3 remains uniform up to the periphery of the peripheral region 2B.

[0127] [Comparative Example]

[0128] Figure 10B It is obtained by enlarging and photographing a flexible printing plate P1 with the same dot pattern in the central region 2A and the same dot pattern in the peripheral region 2B, and setting the angle T to 72° in both.

[0129] For the flexographic printing plate P1, since only one dot pattern needs to be set, the labor and time spent on setting it can be saved. However, the protrusions at the very end of the peripheral area 2B of the printing protrusion 2 are irregularly arranged (poor straightness) (see reference). Figure 10B The amount of ink that can be retained by the groove 4 between the protrusions 3 on the periphery of the peripheral region 2B and the bottom 1 is different.

[0130] The embodiments described herein illustrate specific aspects of the invention, but these embodiments are merely examples and not intended to be limiting. Various modifications that will be apparent to those skilled in the art are included within the scope of this invention.

[0131] Industrial availability

[0132] The present invention is useful as a flexible printing plate that can be uniformly printed up to the periphery.

[0133] Explanation of reference numerals in the attached figures

[0134] 2. Printing relief; 2A. Central area; 2B. Peripheral area (printing direction portion); 2C. Peripheral area (right-angle direction portion); P. Flexographic printing plate; S. Travel direction.

Claims

1. A flexible printing plate, comprising a plurality of printing protrusions formed on its top surface, wherein, The shape of the multiple protrusions when viewed from above forms a dot pattern. The dot pattern is different in the central region of the printing protrusion and in the peripheral region located at the periphery of the central region. In the peripheral region, the dot pattern is different in the printing direction portion and the right-angle direction portion, and the dot distribution density of the printing direction portion is set to be higher than that of the right-angle direction portion.

2. A flexible printing plate, comprising a plurality of printing protrusions formed on its top surface, wherein, The shape of the multiple protrusions when viewed from above forms a dot pattern. The dot pattern is different in the central region of the printing protrusion and in the peripheral region located at the periphery of the central region. The halftone pattern in the central region is an assembly of halftone dots arranged in columns. The angle (T) between the imaginary line (R) connecting the centers of adjacent halftone dots arranged in the columns and the printing direction (S) is set to 11° to 34° or 56° to 79°. The dot pattern in the peripheral area is an assembly of dots arranged in a column. The angle (T) between the imaginary line (R) connecting the centers of adjacent dots arranged in the column and the printing direction (S) is set to 0°±10° or 45°±10°.

3. The flexible printing plate according to claim 2, wherein, In the dot pattern of the peripheral region, the spacing between adjacent dots arranged in the column is set to 20μm to 300μm.

4. The flexographic printing plate according to any one of claims 1 to 3, wherein, The peripheral region has a printing direction portion along the printing direction and a right-angled direction portion along a direction perpendicular to the printing direction. The ratio (W / X) of the width W of the printing direction portion of the peripheral area to the width X of the printing protrusion is set to 0 < W / X < 0.

05.

5. The flexographic printing plate according to any one of claims 2 to 4, wherein, In the dot pattern of the peripheral region, the distances between adjacent dots arranged in the six surrounding directions are set to be equal.

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