TW201617236A - Flexographic printing plate - Google Patents

Abstract

This invention presents a flexographic printing plate, which can rapidly repeat and proceed the operation of transfer printing efficiently even at shorter intervals without generating the undesired situation such as nonuniform concentration of ink after transfer printing, etc. The flexographic printing plate (1) of the present invention is wound on the external periphery surface of the Forme cylinder of flexographic printer, so that the ink on the anilox roller is held on the upper surface of the ink holding protrusions (2a) of the resin plate (2). Also, the held ink is transfer-printed onto the printing surface by contacting with the print (workpiece). The feature of the present invention is that both edges (2e) of the protrusions (2a) at the front and rear in the printing direction form a downhill taper surface to mitigate the abutting impact with the anilox roller.

Description

Flexible printing plate

The present invention relates to a resin-made flexographic printing plate for use in a flexographic printing press.

Flexographic printing is a printing method in which a flexible (flexible) flexible printing plate made of rubber is formed by a resin having a convex portion (image and characters) for ink retention on the surface (hereinafter also Only the "printing plate" is used, and the ink held on the upper surface (top surface) of the ink holding convex portion is transferred onto the object to be printed at a low printing pressure. In the flexible printing, since the ink holding convex portion of the printing plate is relatively soft and can follow the surface of the printed object of various shapes, it is used for printing on a printed body having various thicknesses and the like (for example, refer to the patent literature). 1 etc.).

3 is a schematic configuration view showing a general configuration of a flexible printing machine, and FIG. 4(a) is a plan view (top surface view) showing a flexographic printing plate used in the flexible printing method, and FIG. 4(b) is a view. A side view showing a flexographic printing plate used in the flexographic printing method, and (c) of FIG. 4 is an enlarged schematic view showing a main part of a flexographic printing plate used in the flexographic printing method. Further, in all of the figures, the hollow arrows indicate the "printing direction" of the printing plate (the direction of rotation on the plate cylinder).

As shown in FIG. 3, the main body of the flexible printing machine (rotary type) is constituted by the following: a plate cylinder 10, which is wound with a printing plate 5; an anilox roller 20 and a squeegee (squeege blade) 30. For attaching the ink I to the printing plate 5; an ink replenishing mechanism (ink tank 40); and a moving table 50 for making a flat printed object (workpiece W) and the plate cylinder 10 (printing plate 5) The rotation of the ) moves synchronously in parallel.

Further, as shown in FIGS. 4(a) and 4(b), the flexographic printing plate (printing plate 5) used in the flexographic printing press is formed in a plan view and can be wound around the plate cylinder 10. It is substantially rectangular and consists of a base material 3 which is a film made of polyethylene terephthalate (PET), etc., which supports stretching (tension) when wound on the plate cylinder 10; and resin Plate 6, formed (stacked) on the substrate 3.

As shown in FIG. 4(b), in the central portion of the resin plate 6, on the flat-shaped base portion 6b (non-printing portion) which is not printed, the printing convex portions 6a, 6a for holding the ink are provided. ...formed in a desired pattern (in this example, a plurality of printed patterns in a rectangular shape in a plan view), at the end of the base portion 6b in the "longitudinal direction" (left-right direction shown) in the direction of rotation of the printing direction The fixing portions 6d and 6d used for mounting the plate cylinder 10 are provided through the thin curved portions 6c and 6c.

In general, each of the printing convex portions 6a constituting the printing pattern is produced by a resin curing method using photolithography, and as shown in an enlarged schematic view of FIG. 4(c), the printing direction of each printing convex portion 6a is long. The corner portion (edge 6e) in the side direction is formed into a relatively sharp shape (so-called "angular shape").

In addition, fixtures for mounting a plate cylinder such as vise 4A, 4B (two-point chain) are attached to the respective fixing portions 6d and 6d at both ends in the longitudinal direction, and a fixing member such as a pin or a hook is used as shown in FIG. The printing plate 5 is closely held around the plate cylinder 10 (outer circumference) in a state where the circumferential tension is slightly applied to the entire plate.

Further, in the flexible printing, the ink supplied from the ink tank 40 to the anilox roll 20 and adjusted by the doctor blade (squeege blade) 30 is brought into contact with the printing plate 5. (synchronous rotation) is held at each top of the printing pattern (printing convex portions 6a, 6a, ...), and the ink to be held is supported by the convex portions 6a and the moving table of the printing plate 5 The printed body (work piece W) on 50 is lightly touched and transferred to the surface (printed surface) of the workpiece W, wherein the moving stage 50 is horizontally moved in synchronization with the rotation of the plate cylinder 10. . [Prior Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent No. 4917063

Further, in the transfer (printing) method using the flexible printing plate as described above, since the contact with the surface of the transfer target (contact pressure) is stable and does not damage the surface of the printed body (workpiece), in recent years, gradually It is used in manufacturing processes such as liquid crystals, organic ELs, organic TFTs, and solar panels. In the manufacturing procedure of these materials, the electrode layer, the sealing layer, and the masking layer are formed by flexographic printing on the surface (processing target surface) of the flat glass substrate using an organic solvent-based ink (coating liquid). Etc.; and recently I am exploring how to improve its efficiency (speed).

However, it has been found that when the transfer operation is continuously performed at a short interval (cycle time or tact time) in order to improve the transfer efficiency (machining speed) by using the flexible printing, the workpiece after the transfer is completed The "shading unevenness" of the coating liquid occurs in the moving direction of the workpiece (printing direction) on the surface (processing target surface). After detailed observation, it can be considered that the unevenness of the shading is caused by the amount of coating (adhesion) of the ink and the variation (offset) of the coating thickness in the printing direction, resulting in alternating (in a continuous wave shape or in the printing direction). The moiré pattern has a portion where the ink adhesion amount is large and a portion where the ink adhesion amount is small.

The present invention has been made in view of the above circumstances, and it is an object of the invention to provide a flexographic printing plate capable of quickly repeating without causing unevenness such as unevenness of ink after transfer, even if the transfer operation is performed at a short interval. Transfer is performed efficiently. [The way to solve the problem]

In order to achieve the object, the flexographic printing plate of the present invention comprises: a base portion having a flat plate shape, a mounting portion for the plate cylinder at both ends of the front and rear portions in the printing direction of the printing plate; and a convex portion for holding the ink, Formed on the base according to a predetermined printing pattern; and in a state of being wound around the outer circumference of the plate cylinder of the flexographic printing press, the ink on the surface of the anilox roller is held on the convex portion for holding the ink a surface, and the held ink is transferred onto the surface to be printed by contact with the object to be printed, wherein the front and rear edges of the convex portion in the printing direction are formed to alleviate the flexographic printing plate and the texture The downslope pushes the surface between the rollers to abut the impact.

The inventors of the present invention repeatedly conducted research for solving the problem, and as a result, found that the "darkness unevenness" of the coating liquid was caused by the printing plate on the plate cylinder (the convex portion for holding each ink) and the anilox roller. The impact generated upon contact causes the printing plate (plate cylinder) to undergo periodic vibration (wave rotation). Further, it has been found that when the transfer interval (takt time) of the flexible printing is shortened, the "periodic vibration of the printing plate (plate cylinder)" generated in the previous transfer process is not in the "printing plate" of the primary ink. The process of transferring to the body (workpiece) is finished, and the next transfer process is affected.

In order to prevent the periodic vibration of the printing plate (plate cylinder) from being generated or ending as early as possible, a method of reducing the contact hardness (touching) between the printing plate and the anilox roller by reducing the hardness of the entire printing plate may be considered. However, when durability (printing resistance) is taken into consideration, a certain degree of hardness balance is required, so that the hardness of the entire printing plate including the printing convex portion cannot be excessively lowered. Therefore, the inventors of the present invention have thought of using the shape of the plate to alleviate the impact of the flexographic printing plate in contact with the anilox roller, and found that by first contacting the anilox roller in the flexographic printing plate as described above (again The "edge shape of the convex portion" for holding the ink is set to a push-out shape, and the impact can be greatly alleviated, and the present invention has been completed. [Effects of the Invention]

In the flexographic printing plate of the present invention, the edge portion of the convex portion for ink holding formed on the flat base portion in the printing direction is formed in a push-out shape (downhill pushing surface), and in the flexible printing When the plate is in contact with the anilox roller, the downhill pushing surface is first brought into contact with the anilox roller. According to this configuration, the initial impact when the flexographic printing plate contacts the anilox roll can be alleviated, and the vibration originating from the impact can be suppressed. Further, when the edge portion of the push-out shape of the convex portion for holding the ink is in contact with (transferred) the printed surface of the object to be printed, the impact due to the contact can be suppressed in the same manner as described above. Therefore, the flexographic printing plate of the present invention can prevent the occurrence of "darkness unevenness" of the ink caused by the periodic vibration (wave-like rotation) of the printing plate (plate cylinder) at the time of ink retention and transfer during the above-mentioned synergistic effect. In this case, the ink (coating liquid) can be accurately applied (transferred) into a desired pattern in accordance with the designed film thickness. Further, since the "darkness unevenness" of the ink does not occur, the transfer can be continuously performed at a short transfer interval (takt time).

Further, in the flexographic printing plate of the present invention, if the inclination angle of the downhill pushing surface is set to be inclined from the horizontal downward by 0.01 to 30 degrees in a state where the printing plate is placed on the horizontal surface, it is possible to further By mitigating the first impact when it comes into contact with the anilox roll, it is possible to reliably prevent the occurrence of vibration due to the impact and the unevenness of the ink generated during the transfer.

[Preferred form of implementing the invention]

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. The configuration and function of the flexible printing machine used in the following embodiments are the same as those of the conventional flexible printing machine shown in FIG. 3, and therefore, the same reference numerals are given to the same components as those in FIG. 3, and detailed description thereof will be omitted. Further, in the drawings of the present embodiment, in order to facilitate the understanding of the shape of the detail, the thickness of the flexographic printing plate is highlighted.

Similarly to the conventional example, the flexographic printing plate (printing plate 1) of the present embodiment is also formed by photolithography using a photocurable (photosensitive) resin, and as shown in FIG. 1(a), The flexographic printing plate of the embodiment has a substantially rectangular shape that can be wound around the plate cylinder 10 (Fig. 1 (a)) in a plan view, and includes a base material 3 made of polyethylene terephthalate (PET). A film or the like supports the stretching (tension) when wound around the plate cylinder; and the resin plate 2 is formed (stacked) on the substrate 3.

Further, as shown in FIG. 1(b), in the center portion of the resin plate 2, as in the conventional example, a flat base portion 2b (non-printing portion) which is unrelated to printing is provided with ink for holding ink. The printing convex portions 2a, 2a, ... are formed in a desired pattern shape (in this example, a plurality of rectangular printed patterns are viewed in a plan view), and the "long side direction" of the base portion 2b as a printing direction and a rotation direction (Fig. The end portions in the left-right direction shown are provided with fixing portions 2d and 2d used for mounting the plate cylinder 10 via the thin curved portions 2c and 2c.

Further, as shown in an enlarged schematic view of (a) to (d) of FIG. 2, the printing plate 1 is different from the conventional printing plate (5) in that a printing pattern is formed on the printing plate 1. In each of the printing convex portions 2a (ink holding convex portions), the edge portion 2e (the portion indicated by a grid in FIG. 1) in the printing direction (longitudinal direction) of each printing convex portion 2a is formed as A downhill inclined surface (downhill pushing surface) with a gentler slope. This is a feature of the flexographic printing plate of the present embodiment.

More specifically, the shape of the edge portion 2e (downward sliding surface) of each of the printing convex portions 2a is as shown in the enlarged view of the main part of Fig. 2(a), and the basic push shape is the printing. In a state in which the plate 1 is horizontally placed, the edge portion 2e of the convex portion 2a is formed as a downhill inclined surface, that is, the thickness of the edge portion 2e is gradually thinned toward the outer side of the edge portion at an inclination angle α. Further, in consideration of the contact with the anilox roller 20 after the plate cylinder 10 is mounted, the inclination angle (push-pull angle) α of the downhill pushing surface is usually set in the range of 0.01 to 30 degrees. It should be in the range of 0.5 ° ~ 20 °.

Further, the range of the slope of the downward slope of the edge portion 2e (the distance L from the end surface) is usually set in the range of 1 mm to 8 mm, preferably in the range of 3 mm to 5 mm, and the slope of the downhill slope is from the convex portion 2a. The amount of drooping (distance H) from the upper surface (top surface) is usually set to 0.05 mm to 0.5 mm, preferably 0.1 mm to 0.25 mm. Further, in the example of (a) of FIG. 2, the push-out surface is designed such that the inclination angle α is 10°, and the range of the downhill push-out surface (distance L from the end surface) is 5 mm, from the convex portion The amount of droop (distance H) from the upper surface (top surface) of 2a is 0.25 mm.

In addition, the push-out shape of the edge portion 2e of the convex portion 2a may be a rounded (R) shape bent downward as shown in FIG. 2(b), or may be as shown in FIG. 2(c). Engraved shape (concave shape). Further, the push-out shape of the edge portion 2e does not have to be formed in a single layer, and may be a stepped shape in which the inclination angle changes in the middle as shown in FIG. 2(d) (pushing the overall downhill inclination angle α) In the range of 0.01° to 30°, there is also a composite curved surface such as a Gothic arc.

As the material constituting the flexographic printing plate (printing plate 1), a material which has a certain elasticity after the plate is formed by using a resin, a rubber or the like is used. In addition, the printing plate 1 of the present embodiment is used for transferring an organic solvent-based ink such as an electrode layer, a sealant, and a masking agent to a substrate (workpiece W) in a manufacturing process of a liquid crystal, an organic EL, or an organic TFT. In addition, it is determined in consideration of the kind of the organic solvent contained in the ink, the plate cleaning liquid, and the like used in the procedure, in consideration of the degree of swelling of the resin, and the like.

Further, it is suitable to use the photolithography method when manufacturing the printing plate 1. In this case, a photosensitive (photocurable) resin composition is used as the material constituting the printing plate 1, and acrylic acid, polyester, polybutadiene or the like is preferably used. A photosensitive resin composed of a prepolymer having an ester as a main skeleton, an acrylate oligomer, a mixture of an acrylate monomer, a photopolymerization inhibitor, a photopolymerization initiator, and the like.

Further, the outer dimensions of the printing plate 1 depend on the size of the substrate (workpiece W) to be the printed body and the size of the plate cylinder 10, and are usually 300 mm to 2300 mm in the printing direction (longitudinal direction of the printing plate 1). The left and right sides are about 500 mm to 2800 mm in the width direction (the lateral direction of the printing plate 1). Further, the length of the curved portion 2c having a small thickness in the printing direction (longitudinal direction) is set to about 0 mm to 100 mm, and the length of the fixed portion 2d in the printing direction (longitudinal direction) is set to about 15 mm to 40 mm.

Further, the hardness of the printing convex portion 2a of the printing plate 1 is desirably set in the range of JIS Shore A rubber hardness of 35 to 70 degrees. When the Shore A hardness is less than 35 degrees, there is a tendency that the printing convex portion 2a is too soft with respect to the substrate (work W) and is deformed at the time of printing, so that high-definition printing cannot be maintained. On the contrary, in the case where the Shore A hardness of the flexographic printing plate is greater than 70 degrees, there is a tendency that the surface of the substrate (work W) is damaged, and electrodes, wiring, and the like formed on the surface are also damaged.

Further, the film-form substrate 3 located on the back side of the printing plate 1 is formed by laminating one or two or more layers of a resin film (or sheet), and polyphenylene is used in this example (Fig. 1). Two-layer film made of ethylene diformate (PET). As the resin forming the film-form substrate 3, other resins such as polypropylene (PP) or polyvinyl chloride (PVC) may be used. Further, in the entire thickness of the single film-form substrate 3, a film having a thickness of about 0.1 mm to 0.5 mm is used, and the entire thickness of the fixing portion 2d including the end portion of the printing plate 1 is adjusted to 1.5 mm to 3.0. Mm or so.

According to the flexographic printing plate having the above configuration, since the edge portions 2e and 2e of the printing convex portion 2a in the front and rear of the printing direction are formed as the push-down surface inclined downward, it is possible to alleviate the contact between the printing plate 1 and the anilox roller 20. The initial impact. Thereby, it is possible to suppress the occurrence of vibration on the printing plate 1 and the plate cylinder 10 due to the impact, and it is possible to prevent the occurrence of "darkness unevenness" of the ink generated after the transfer. Not yet. Further, in the flexible printing using the flexographic printing plate, since the problem of "darkness unevenness" of the ink does not occur, the transfer can be efficiently and continuously performed at a short transfer interval (beat time). [Industry Utilization]

The flexographic printing plate of the present invention can be suitably used for printing (transfer formation) of an electrode layer, a sealant, a masking agent, and the like provided on a substrate such as a liquid crystal, an organic EL, or an organic TFT, and can contribute to improvement Its production efficiency.

1‧‧‧Printing
2‧‧‧ resin version
2a‧‧‧ convex
2b‧‧‧ base
2c‧‧‧Bend
2d‧‧‧Fixed Department
2e‧‧‧ (protruding) edge
3‧‧‧Substrate
4A, 4B‧‧‧ vise
5‧‧‧Printing
6‧‧‧ resin version
6a‧‧‧ convex
6b‧‧‧ base
6c‧‧‧Bend
6d‧‧‧Fixed Department
6e‧‧‧ (protruding) edge
10‧‧‧ plate cylinder
20‧‧‧Anilox roller
30‧‧‧Scraping parts
40‧‧‧Ink tank
50‧‧‧Mobile Station
W‧‧‧Workpiece
H‧‧‧Drop amount (distance)
L‧‧‧Distance from the end (the range of the downhill push surface)
‧‧‧‧Tilt angle

Fig. 1 (a) is a plan view of a flexographic printing plate according to an embodiment of the present invention, and Fig. 1 (b) is a side view of a flexographic printing plate according to an embodiment of the present invention. (a) to (d) of FIG. 2 are each a schematic view showing a shape example of both edge portions (corner portions) of the printing convex portion of the flexographic printing plate according to the embodiment of the present invention. 3 is a schematic configuration view showing a general configuration of a flexible printing machine. Fig. 4 (a) is a plan view of a conventional flexographic printing plate, Fig. 4 (b) is a side view of a conventional flexographic printing plate, and Fig. 4 (c) shows both edges of the printing convex portion (corner) Schematic diagram of the shape of the crotch).

2a‧‧‧ convex

2b‧‧‧ base

2e‧‧‧ (protruding) edge

H‧‧‧Drop amount (distance)

L‧‧‧Distance from the end (the range of the downhill push surface)

‧‧‧‧Tilt angle

Claims (2)

A flexographic printing plate comprising: a base portion having a flat shape, a mounting portion for a plate cylinder at both ends of the front and rear portions in a printing direction of the printing plate; and a convex portion for holding ink, which is formed according to a predetermined printing pattern Above the base; and in a state of being wound around the outer circumference of the plate cylinder of the flexographic printing press, the ink on the surface of the anilox roller is held on the upper surface of the convex portion for ink retention, and by The ink to be held is transferred to the surface to be printed in contact with the object to be printed, and the edge portion of the convex portion in front of and behind the printing direction is formed to alleviate the flexible printing plate and the anilox roller. Abutting the impact of the downhill push surface. The flexographic printing plate of claim 1, wherein the inclination angle of the downhill pushing surface is set as follows: in a state where the printing plate is placed on a horizontal surface, the angle is inclined downward from the horizontal by 0.01° to 30°. .