JP2020003752A - Oriented film printing plate, oriented film printing device, and method for forming oriented film - Google Patents

Abstract

To provide an oriented film printing plate, an oriented film printing device, and a method for printing an oriented film which can easily respond to increase of size and production of a large number of types in small amounts and can provide a high-quality oriented film free from unevenness in printing.SOLUTION: There is provided an oriented film printing plate 10 wound around a plate cylinder 24 when is used to form an oriented film on a glass substrate by transferring a print solution applied on a printing surface 14 to the glass substrate. The printing surface 14 of the oriented film printing plate 10 is divided in a plurality of unit print surfaces 14a to 14d in the pattern of a stripe by at least one trench groove 16 reaching the end part of the lower side from the end part of the upper side, each of the unit print surfaces 14a to 14d being flat.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an alignment film printing plate, an alignment film printing apparatus, and an alignment film forming method capable of easily forming a high-quality alignment film with no printing unevenness, which can easily cope with an increase in size and a large variety of small-quantity production. .

  Liquid crystal display elements of various sizes are generally used as display screens of electronic devices such as smartphones, portable game machines, calculators, and watches.

  Such a liquid crystal display element has, as a main component, an alignment film formed on a glass substrate on which electrodes, a color filter, an insulating film, etc. are formed, and is used as a method for forming an alignment film on a glass substrate. A method using flexographic printing (Patent Document 1) and a method using inkjet printing (Patent Document 2) are known.

  Flexographic printing is a method using an alignment film printing plate (so-called letterpress plate) in which the printing surface has irregularities in the printing pattern. The printing liquid (general) is applied to a plate cylinder around which the alignment film printing plate is wound via an anilox roller. Specifically, an alignment film is formed on a glass substrate by applying polyimide and rolling the same on a glass substrate.

  On the other hand, ink jet printing is a method using an ink jet printer, in which an alignment film is formed on a glass substrate by discharging a printing liquid from nozzle holes of the printer head toward the glass substrate while moving the printer head over the glass substrate. It is formed.

JP 2014-98734 A (FIG. 1) JP-A-2015-87652 (FIG. 4)

  In recent years, the demand for liquid crystal display elements has been rapidly increasing, and accordingly, a glass substrate having a size of G10 class (2850 × 3050 mm) or more has been required. In addition, since the shape and size of the liquid crystal display element are diversified, there is a strong demand that the liquid crystal display element can quickly respond to the production of various kinds and in small quantities. Insufficient coating on contact holes or shortage of coatings on contact holes (for the purpose of ensuring current flow between electrodes, a small opening formed in the insulating film interposed between the electrodes is called a "contact hole". There is also a high demand for quality, for example, it is required to prevent printing unevenness such as not being filled with a film.

  To develop an alignment film printing device that satisfies all of these requirements, such as large size, high-mix low-volume production, and high quality, we strive to develop an alignment film printing device. Then, there were advantages and disadvantages as shown below.

  For example, in the case of flexographic printing, there is a merit that a printing plate wound around a plate cylinder is pressed against a glass substrate to apply a printing pressure to the alignment film, thereby obtaining a high-quality alignment film without printing unevenness. In order to cope with small-volume production of multiple types, it is necessary to prepare a plurality of types of alignment film printing plates (letter plates) with different printing patterns and replace them by hand. There was a problem that it was not suitable for production.

  On the other hand, in the method by ink-jet printing, since the print pattern can be changed instantaneously only by changing the data, it is possible to quickly respond to high-mix low-volume production, but regarding the quality of the alignment film, Since the printing liquid is simply applied to the glass substrate in a non-contact manner, no printing pressure is applied to the alignment film, and it is difficult to form a high-quality alignment film without printing unevenness such as flexographic printing. (It is technically very difficult to fill a small opening such as a contact hole with a viscous liquid such as a printing liquid without applying a printing pressure).

  Then, the inventors tried to solve the above problem by a method (hybrid method) combining flexographic printing and inkjet printing. A flat alignment film printing plate without irregularities (so-called solid plate) is wound around a plate cylinder, and a printing liquid is applied to the printing surface of the alignment film printing plate (solid plate) by ink jet printing in accordance with the printing pattern, and then the glass substrate is used. By rolling on the upper side, an alignment film is formed on a glass substrate.

  According to this hybrid method, rapid response to high-mix low-volume production by ink-jet printing and high quality of the alignment film by rolling the plate cylinder on the glass substrate and applying printing pressure to the alignment film are simultaneously performed. Although it is possible to satisfy them, they face the problem of increasing the size as described below. In other words, in order to cope with an increase in the size of the glass substrate, it is necessary to increase the size of the alignment film printing plate and the plate cylinder around which the alignment film printing plate is wound, but an alignment film printing plate (solid plate) having no unevenness on the surface is used. As a result, a new problem of "breaking of the glass substrate" has arisen.

  That is, the glass substrate is fixed by suction on the surface plate by air suction or the like. As described above, the plate cylinder on which the alignment film printing plate is rolled rolls on the glass substrate that is adsorbed and fixed on the surface plate. However, in a portion where the printing liquid is not applied, the alignment film printing plate is used. Will come into direct contact with the glass substrate.

  Since the printing surface of the alignment film printing plate is formed using an elastic resin such as rubber, the alignment film printing plate adheres to the glass substrate by the printing pressure during rolling. Then, by the sticking force and the rotation of the plate cylinder, a force for peeling the glass substrate from the platen is applied to the glass substrate.

  As described above, in a portion where the printing liquid is not applied, the suction fixing force by the surface plate and the peeling force by the alignment film printing plate are irregularly applied to the glass substrate, thereby forming a thin glass substrate. It breaks easily.

  The present invention has been made in view of such conventional problems, and is easy to cope with upsizing, high-mix low-volume production, and is capable of forming a high-quality alignment film without printing unevenness. An object of the present invention is to provide a film printing plate, an alignment film printing apparatus, and an alignment film printing method.

  The invention described in claim 1 is directed to a method in which “the alignment film X is formed on the glass substrate W by transferring the printing liquid M applied to the printing surface 14 to the glass substrate W by being used by being wound around the plate cylinder 24. The printing surface 14 of the alignment film printing plate 10 has a plurality of elongated strip-shaped unit printing surfaces 14a formed by one or a plurality of grooves 16 extending from an upstream end to a downstream end thereof. To 14d, and the surface of each unit printing surface 14a to 14d is a flat surface. "

  The invention described in claim 2 is that the edge grooves 18 extending in a direction substantially perpendicular to the concave grooves 16 are provided on the unit printing surfaces 14a to 14d at positions corresponding to the printing end side of each printing pattern P. Formed on the alignment film printing plate 10.

  According to a third aspect of the present invention, there is provided a platen 22 on which a glass substrate W is placed, and the alignment film printing plate 10 according to the first or second aspect wound around the outer periphery. A printing cylinder 26 that rolls, and a printing unit 26 that prints a printing pattern P on each of the unit printing surfaces 14a to 14d by discharging the printing liquid M onto the printing surface 14 of the alignment film printing plate 10. " An alignment film printing apparatus 20 characterized by the following.

According to a fourth aspect of the present invention, there is provided a method according to the first aspect, wherein the alignment film printing plate according to the first or second aspect is wound around the outer peripheral surface of the plate cylinder and attached.
By discharging the printing liquid M from the printer head 32 of the printing unit 26 toward the alignment film printing plate 10, the printing pattern P is printed on each of the unit printing surfaces 14a to 14d, and thereafter, the plate cylinder 24 and the alignment film printing are performed. Rolling the integrated body with the plate 10 on the glass substrate W ".

  In the present invention, since the printing surface of the alignment film printing plate is divided into a plurality of elongated belt-shaped unit printing surfaces by the concave grooves, when the plate cylinder rolls on the glass substrate, the printing liquid is not applied. The peeling force at is greatly dispersed and reduced by the groove. Therefore, even if the size of the alignment film printing plate is increased to, for example, G10 class or more, a large peeling force is not applied to the glass substrate, and the glass substrate does not crack during printing.

  Since the printing liquid is applied to the printing surface by ink-jet printing, it is possible to quickly respond to high-mix low-volume production, and there is no printing unevenness by rolling while pressing the plate cylinder against the glass substrate. A high-quality alignment film can be formed.

FIG. 1 is a view showing an alignment film printing plate according to one embodiment of the present invention. FIG. 1 is a view showing an alignment film printing apparatus according to the present invention. FIG. 2 is a diagram illustrating a state in which an alignment film is printed on a glass substrate using the alignment film printing apparatus according to the present invention. It is a figure which shows an example of the printing pattern of an orientation film printing plate. It is a figure which shows the other example of the printing pattern of an orientation film printing plate.

  Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an alignment film printing plate 10 according to the present invention, and FIG. 2 is a diagram illustrating an alignment film printing apparatus 20 according to the present invention. First, the alignment film printing plate 10 will be described, and then, the alignment film printing device 20 will be described.

  As shown in these figures, the alignment film printing plate 10 is a sheet-like member that is attached by being wound around the outer periphery of a plate cylinder 24 described later, and is used to form the alignment film X on the glass substrate W, The size is appropriately set according to the size of the plate cylinder 24.

  In this embodiment, the orientation film printing plate 10 has a three-layer structure, the plate cylinder 24 side is a carrier film 10a which is a thin film layer made of PET (polyethylene terephthalate), and the center portion is a base film 10b. The printing surface side is a resin layer 10c made of an elastic resin such as rubber (see the inside of the right circle in FIG. 1), and the overall thickness is set to 0.5 to 3.0 mm (2.5 mm in this embodiment). . In addition, for simplicity, in FIG. 2 and subsequent drawings, the alignment film printing plate 10 is depicted as one sheet-shaped member.

  Both ends of the short side of the alignment film printing plate 10 are dug in one step to form a stepped shape, and the stepped portion serves as a mounting portion 12 (12a, 12b) to the plate cylinder 24. A plurality (five in this embodiment) of fixing holes 12c are formed in each of the mounting portions 12 (12a, 12b) at predetermined intervals.

  In the upper surface of the alignment film printing plate 10 (the surface opposite to the surface in contact with the plate cylinder 24), a portion sandwiched between the mounting portions 12a and 12b is the printing surface 14. On the printing surface 14, one or more (three in this embodiment) concave grooves 16 are formed in parallel from each other at a predetermined interval from the edge of the one mounting portion 12a to the edge of the other mounting portion 12b. Have been. As a result, the printing surface 14 of the alignment film printing plate 10 is divided into a plurality of (four in this embodiment) unit printing surfaces 14a to 14d.

  Each of the unit printing surfaces 14a to 14d is an elongated strip portion, and the surface thereof is a flat surface. In the present embodiment, the width of each of the unit printing surfaces 14a to 14d is set to be equal, but of course, may be different for each of the unit printing surfaces 14a to 14d. The shape of each groove 16 is an upward U-shape, and in this embodiment, the left and right side walls 16a, 16b and the bottom surface 16c are orthogonal to each other at substantially 90 degrees (see the left circle in FIG. 1). ).

  Next, the alignment film printing apparatus 20 will be described. The alignment film printing apparatus 20 is generally constituted by a surface plate 22, a plate cylinder 24, and a printing unit 26. The above-described alignment film printing plate 10 is used by being wound around the outer periphery of the plate cylinder 24.

  The platen 22 is a flat plate on which the glass substrate W is placed. A plate cylinder 24 is disposed above the platen 22 so as to be movable with respect to the platen 22. A plurality of suction holes (not shown) are provided on the upper surface (mounting surface) of the surface plate 22, and the glass mounted on the surface plate 22 by applying a negative pressure to the lower surface of the surface plate 22. The substrate W can be fixed by suction.

  The plate cylinder 24 is a columnar member having a first mounting recess 24a and a second mounting recess 24b formed on the outer peripheral surface thereof, and a plate vise 44 (44A, 44B) described later. ) Are detachably attached.

  The printing unit 26 is for applying the printing liquid M to the printing surface 14 (the unit printing surfaces 14a to 14d) of the alignment film printing plate 10 in a non-contact (inkjet method) to form a printing pattern P. As shown in FIG. 3, the printing unit 28 and the control unit 30 are roughly configured.

  The printing unit 28 is a part that discharges the printing liquid M toward the alignment film printing plate 10, and includes a printer head 32 and a circulation tank 34. These are one unit above the plate cylinder 24 above the plate cylinder 24. It can be moved on the surface plate 22 in accordance with the movement of 24.

  The printer head 32 is disposed so as to cover the entire width of the alignment film printing plate 10 above the alignment film printing plate 10 wound around the plate cylinder 24, and has a plurality of small nozzle holes on its lower surface. 32a are formed at predetermined intervals. From each of the nozzle holes 32a, a printing liquid M serving as a raw material of the alignment film X is discharged toward the printing surface 14 (unit printing surfaces 14a to 14d) of the alignment film printing plate 10, whereby the alignment film printing plate 10 The printing pattern P of the printing liquid M is printed (primary transfer) on the printing surface 14 (each unit printing surface 14a to 14d) (FIG. 4). A circulation tank 34 is connected to the printer head 32. The circulation tank 34 supplies the printing liquid M to the printer head 32 and collects the printing liquid M not used for printing.

  In this embodiment, the entire width of the alignment film printing plate 10 is covered by one large printer head 32. However, a plurality of small printer heads are arranged so as to cover the entire width of the alignment film printing plate 10. It may be.

  The control unit 30 is a unit that controls the supply and discharge of the printing liquid M to the printing unit 28 and the movement of the printing unit 28, respectively. The printing liquid supply / discharge control unit 36, the printing unit movement control unit 38, the printing liquid supply tank 40 and a waste liquid tank 42.

  The printing liquid supply / discharge control unit 36 supplies new printing liquid M from the printing liquid supply tank 40 to the circulation tank 34, collects unnecessary printing liquid M from the circulation tank 34 to the waste liquid tank 42, and prints the print head 32. The discharge of the printing liquid M from the nozzle holes 32a is controlled respectively. The printing unit movement control unit 38 controls the movement of the printing unit 28 on the surface plate 22 in accordance with the movement of the plate cylinder 24 described above.

  A method of forming the alignment film X on the glass substrate W using the alignment film printing plate 10 and the alignment film printing device 20 will be described. First, the alignment film printing plate 10 is wound around the outer periphery of the plate cylinder 24 and attached. The attachment of the alignment film printing plate 10 to the plate cylinder 24 is performed using the plate vise 44 (44A, 44B). Each plate vise 44 (44A, 44B) has a vice main body 44a and a bracket 44b integrally fixed to the vise main body 44a via bolts 46. The vise main body 44a and the bracket 44b are used to form the alignment film printing plate 10. The mounting portions 12 (12a, 12b) are clamped and fixed respectively. A bolt 46 is inserted into a fixing hole 12c provided in the mounting portion 12a of the alignment film printing plate 10.

  The plate vise 44A sandwiching one side (upstream side) of the alignment film printing plate 10 in the circumferential direction is fixed to the first mounting recess 1a provided in the plate cylinder 24, and the circumference of the alignment film printing plate 10 is fixed. The plate vise 44B holding the other side (downstream side) is attached to the second attachment recess 1b provided on the plate cylinder 24 (see FIG. 2). Thereby, the attachment of the alignment film printing plate 10 to the plate cylinder 24 is completed. A cylinder 48 (see FIG. 2) is connected to the plate vise 44B on the downstream side, and the cylinder 48 draws the plate vise 44B downstream to apply tension to the alignment film printing plate 10.

  Next, a printing liquid M (generally, polyimide) is applied to the printing surface 14 of the alignment film printing plate 10, more specifically, to each of the unit printing surfaces 14a to 14d. This application step is performed by inkjet printing using the printing unit 26.

  The print pattern P formed on each of the unit print surfaces 14a to 14d can be set to an arbitrary shape by setting the pattern data of the print pattern P in the control unit 30. In the present embodiment, as shown in FIG. 4, all the print patterns P formed on the unit print surfaces 14a to 14d are set to have the same size and the same shape (rectangular shape). Print patterns P of different sizes and shapes may be formed for the surfaces 14a to 14d. Also, the print patterns P printed on each unit print surface 14a (14b, 14c, 14d) may be all the same size and shape, or may be a combination of different size and shape print patterns P. . A margin m is provided between the boundary between the unit printing surfaces 14a to 14d and each printing pattern P (see the circle in FIG. 4). M splashing is prevented.

  Next, the transfer (secondary transfer) of the print pattern P primarily transferred to the print surface 14 to the glass substrate W will be described. The plate cylinder 24 rolls rightward on the glass substrate W in FIG. The printing pattern P is applied to the printing surface 14 (each unit printing surface 14a to 14d) of the alignment film printing plate 10 wound around the plate cylinder 24.

  When the printing surface 14 of the alignment film printing plate 10 is rotated while lightly contacting the glass substrate W, the printing pattern P applied to the printing surface 14 (each unit printing surface 14a to 14d) is printed on the glass substrate W ( (Secondary transfer), and the desired alignment film X is formed on the glass substrate W.

  Here, in the portion (non-printed portion) A (FIG. 4) of the alignment film printing plate 10 where the print pattern P is not formed, the printing surface (more specifically, the resin layer 10 c) of the alignment film printing plate 10 and the glass substrate W And the resin layer 10c is stuck to the glass substrate W by direct contact, but the sticking force is such that the printing surface 14 of the alignment film printing plate 10 is divided into a plurality of unit printing surfaces 14a to 14d by the concave grooves 16. When the plate cylinder 24 rolls, the non-printing portion A of the alignment film printing plate 10 is immediately separated from the glass substrate W. Therefore, even if the size of the glass substrate W is increased, a large peeling force is not applied to the glass substrate W when the plate cylinder 24 rolls, so that the glass substrate W can be prevented from cracking.

  In addition, since the printing liquid M is applied to the printing surface 14 (each of the unit printing surfaces 14a to 14d) by ink-jet printing, it is possible to quickly cope with high-mix low-volume production. By rolling up and applying a printing pressure, it is possible to form a high-quality alignment film X without printing unevenness.

  In the above embodiment, the primary transfer and the secondary transfer are performed at the same time, but both may be performed as separate steps. Further, the secondary transfer is performed by fixing the position of the platen 22 and making the plate cylinder 24 movable. However, the position of the plate cylinder 24 is fixed and the platen 22 is movable. May be used to perform secondary transfer.

  In the above-described method in which the alignment film printing plate 10 wound around the plate cylinder 24 is lightly pressed against the glass substrate W and rolled to perform secondary transfer, the printing end side of each print pattern P (FIG. 5, the printing liquid M is extruded to the downstream side, and the edge line of the printing pattern transferred to the glass substrate W is distorted. In such a case, an edge groove 18 orthogonal to the concave groove 16 may be provided at a position corresponding to the printing end side of each print pattern P as shown in FIG. It is possible to beautifully finish the edge line of the print pattern transferred to the printer.

10: alignment plate printing plate, 10a: carrier film, 10b: base film, 10c: resin layer, 12 (12a, 12b): mounting portion, 12c: fixing hole, 14: printing surface, 14a to 14d: unit printing surface, 16: concave groove, 16a, 16b: side wall, 16c: bottom surface, 18: edge groove, 20: alignment film printing device, 22: platen, 24: plate cylinder, 24a: first mounting recess, 24b: second Mounting recess, 24c: rotating shaft, 26: printing unit, 28: printing unit, 30: control unit, 32: printer head, 32a: nozzle hole, 34: circulation tank, 36: printing liquid supply / discharge control unit, 38 : Printing unit movement control unit, 40: printing liquid supply tank, 42: waste liquid tank, 44: plate vise, 44a: vice body, 44b: bracket, 46: bolt, 48: cylinder, A: no print pattern is formed Min (non-printed portion), m: margin, M: printing fluid, P: printing pattern, W: glass substrate, X: an alignment film

Claims (4)

An alignment film printing plate that is used by being wound around a plate cylinder, and forms an alignment film on the glass substrate by transferring a printing liquid applied to the printing surface to the glass substrate,
The printing surface of the alignment film printing plate is divided into a plurality of elongated strip-shaped unit printing surfaces by one or more concave grooves extending from an upstream end to a downstream end thereof, and a surface of each unit printing surface is provided. A printing plate having a flat surface.   2. The unit printing surface according to claim 1, wherein an edge groove extending in a direction substantially orthogonal to the concave groove is formed at a position corresponding to a printing end side of each of the printing patterns. The printing plate for an alignment film according to the above. A platen on which a glass substrate is placed;
A plate cylinder around which the alignment film printing plate according to claim 1 or 2 is wound, and which rolls on the glass substrate,
A printing unit for printing a printing pattern on each unit printing surface by discharging a printing liquid onto a printing surface of the alignment film printing plate. The orientation film printing plate according to claim 1 or 2, which is wound around the outer peripheral surface of the plate cylinder and attached,
A printing pattern is printed on each of the unit printing surfaces by discharging a printing liquid from the nozzle holes of the printing unit toward the alignment film printing plate, and thereafter, an integrated product of the plate cylinder and the alignment film printing plate Is rolled on the glass substrate.