Optical film feeding method

Abstract

To provide a paper feeding method for optical films which barely causes poor appearances in the optical films.SOLUTION: The present invention provides a method for feeding an optical film F1 to a pass line of a conveyance facility 100B having a driving roller R1 and driven rollers R2 forming a nip roller R. When the optical film F1 can be fed only by bringing the optical film F1 into contact with the driven rollers R2, in an open state of the nip roller R, the optical film F1 is brought into contact only with the driven rollers R2, and the driving of the driving roller R1 is stopped when feeding the optical film F1.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for passing an optical film such as a polarizing film, and more particularly to a method for passing an optical film which is less likely to cause defects in the appearance of the optical film. [Background technology]

[0002] Conventionally, optical films have been used in image display devices such as liquid crystal display devices and organic EL display devices. Examples of optical films include polarizing films (polarizers), polarizing plates including polarizing films, retardation films, and anti-glare films. Optical films are usually manufactured using a long strip of raw film. The raw film is conveyed in the longitudinal direction by a conveying device and sequentially subjected to various processes to produce a long strip of optical film as a product. The long strip of optical film is cut to a size according to the application and used in an image display device or the like. Hereinafter, in this specification, the term "optical film" refers not only to optical films as products, but also to raw films and films in intermediate products.

[0003] Equipment for transporting optical films usually has a driving roller and a driven roller (also called a free roller) (see, for example, Patent Documents 1 and 2). The drive roller is a roller that is driven to rotate by a motor and transports the optical film in the longitudinal direction by frictional force, and the driven roller is a roller that rotates freely and guides the optical film transported in the longitudinal direction.

[0004] When starting the production of optical film products, it is necessary to perform an operation of passing the optical film along a path line (a transport path for the optical film determined by the positions of the drive roller and the driven roller) of the transport equipment having the drive roller and the driven roller. The paper passing operation is an operation in which a person manually pulls the leading end of the optical film to hang the optical film on the drive roller and the driven roller, and aligns the optical film with the path line.

[0005] For example, when the optical film is a polarizing film, it is not possible to splice one original film and the next original film (connecting the rear end of the first original film and the leading end of the next original film) and transport the film. The original film of the polarizing film is stretched in a processing bath, so even if it is spliced ​​with a general tape or laser welding, the spliced ​​part will come off. Therefore, every time the original film wound around the pay-out roller runs out, the original film wound around the next pay-out roller is manually fed.

[0006] Conventionally, the optical film may be rubbed or cut during the above-mentioned paper-passing operation. In particular, the thinner the optical film, such as a polarizing film, the more likely it is that the optical film will be rubbed or cut during the paper-passing operation. Even if the leading edge of the optical film is rubbed or cut and damaged, no particular problem will occur as long as the leading edge that has been subjected to the paper-passing operation is not used as a product. However, problems may occur due to the wear and tear of the optical film, which may cause unevenness on the surface of the driving roller or driven roller (usually made of rubber material), or the generation of foreign matter made of the material forming the optical film or the rubber material on the surface of the driving roller, etc. Specifically, once unevenness occurs on the surface of the driving roller, etc., it cannot be fixed until it is replaced, so the unevenness on the surface of the driving roller, etc. may be transferred to the optical film during normal transport after the paper feed operation is completed, causing a defective appearance of the optical film. In addition, the foreign matter that occurs floats for a long time in the atmosphere or treatment tank in which the optical film transport equipment is installed, and the foreign matter may adhere to the optical film, causing a defective appearance of the optical film. For example, even if the unevenness or foreign matter is about several tens of μm in size, if it is visible, the optical film will have a defective appearance, which may lead to a decrease in the product yield. For this reason, it is desired to prevent the occurrence of defective appearance of the optical film caused by wear and tear of the optical film during the paper feed operation as much as possible. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2013-248590 A [Patent Document 2] JP 2004-341515 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made to solve the problems of the conventional techniques as described above, and an object of the present invention is to provide a method for passing an optical film which is less likely to cause defects in the appearance of the optical film. [Means for solving the problem]

[0009] In order to solve the above problem, the present inventors conducted extensive research and found that one of the causes of wear and tear during paper feed operation is the drive roller of the conveying equipment. Specifically, in the past, the drive roller was always stopped during paper feed operation. When the drive roller is stopped, the drive roller does not rotate during paper feed operation. For this reason, slippage occurs between the drive roller and the optical film hung on the drive roller, causing wear and tear on the optical film.

[0010] The present invention has been completed based on the above-mentioned findings of the present inventors. In other words, in order to solve the above-mentioned problems, the present invention provides a method for passing an optical film through a pass line of a conveying equipment having a drive roller and a driven roller, in which, when the optical film is brought into contact with the drive roller to apply tension to the tip portion of the optical film, the drive roller is driven to bring the drive roller into a rotating state.

[0011] According to the present invention, at least when the optical film is brought into contact with the drive roller to apply tension to the leading end of the optical film, the drive roller is driven to rotate, so that slippage of the optical film against the drive roller is suppressed, and the optical film is less likely to be worn or cut, which makes it less likely to cause defects in appearance of the optical film.

[0012] In the present invention, it is preferable that the driving roller is driven before the optical film is brought into contact with the driving roller.

[0013] According to the above-mentioned preferable method, it is possible to reliably prevent the occurrence of abrasion or cutting of the optical film.

[0014] In the present invention, it is preferable that the rotation speed of the drive roller when the optical film is passed through is set to be equal to or lower than the rotation speed of the drive roller during normal transport after the optical film is passed through.

[0015] According to the above-mentioned preferable method, it is possible to enhance the safety of the paper passing operation and also to facilitate the paper passing operation.

[0016] The present invention is preferably used when the drive roller is a drive roller of a nip roller, which is a roller in which a drive roller and a driven roller are arranged opposite each other and transport an optical film between the rollers.

[0017] The present invention also provides a method for passing an optical film through a pass line of a conveying facility having a drive roller and a driven roller opposing the drive roller, which constitutes a nip roller, and when the optical film can be passed through simply by contacting the optical film with the driven roller, the nip roller is opened, the optical film is brought into contact only with the driven roller, and the drive of the drive roller is stopped when the optical film is passed through.

[0018] According to the present invention, since the driving of the drive roller is stopped during the paper-passing operation of the optical film, it is possible to improve the safety of the paper-passing operation. Furthermore, even if the driving of the drive roller is stopped, it is not necessary to bring the optical film into contact with the drive roller during the paper-passing operation, so that it is possible to suppress the occurrence of abrasion or cutting of the optical film caused by the optical film slipping against the stopped drive roller.

[0019] The present invention is suitably used when the optical film is a polarizing film (including raw polarizing film and intermediate product film). Effect of the Invention

[0020] According to the present invention, the optical film is less likely to be rubbed or cut when the optical film is passed through, and the optical film is less likely to have poor appearance. [Brief description of the drawings]

[0021] [Figure 1] 1 is a schematic diagram showing an example of the schematic configuration of a manufacturing facility for a polarizing plate including a polarizing film to which a paper passing method according to an embodiment of the present invention is applied. [Diagram 2] 1 is a schematic diagram partially illustrating an example of a conveying facility to which a paper passing method according to an embodiment of the present invention is applied; [Diagram 3] 3 is an explanatory diagram showing a procedure for passing a polarizing film through a pass line of the conveying facility shown in FIG. 2 using a passing method according to one embodiment of the present invention. FIG. [Figure 4] 11 is a schematic diagram partially illustrating an example of another conveying facility to which a sheet passing method according to an embodiment of the present invention is applied. FIG. [Diagram 5] 13 is a schematic diagram partially illustrating an example of still another conveying facility to which a sheet passing method according to an embodiment of the present invention is applied. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, with reference to the accompanying drawings as appropriate, a method for passing an optical film according to one embodiment of the present invention will be described, taking as an example a case in which the optical film is a polarizing film.

[0023] 1 is a schematic diagram showing an example of the schematic configuration of a manufacturing facility for a polarizing plate including a polarizing film to which the paper-passing method according to the present embodiment is applied. The arrows shown in FIG. 1 indicate the transport direction of each film. In manufacturing a polarizing plate F using the manufacturing equipment shown in Fig. 1, first, a raw film F0 such as a polyvinyl alcohol-based film wound around a pay-out roller 1 is paid out and immersed in a treatment bath in a treatment tank 2, where it is dyed with a dichroic substance such as iodine or a dichroic dye and uniaxially stretched. Next, it is dried in an oven 3 to obtain a polarizing film F1. The thickness of the polarizing film F1 is not particularly limited, but is generally about 1 to 80 µm, and preferably 1 to 20 µm.

[0024] Next, a gravure coater 6 applies an ultraviolet-curing adhesive (hereinafter referred to as a UV adhesive) to one side of the protective film F2 paid out from the pay-out roller 5. Then, a lamination roller 7 laminates the protective film F2 coated with the UV adhesive to both sides of the polarizing film F1. Next, the UV adhesive is cured by an ultraviolet irradiator 8, and then dried in an oven 9. Finally, a surface protective film F3 paid out from a pay-out roller 10 is laminated by a lamination roller 11 to one side of the polarizing film F1 with the protective film F2 laminated to both sides, thereby obtaining a polarizing plate F. The obtained polarizing plate F is taken up by a take-up roller 12.

[0025] The paper passing method according to this embodiment is used in the conveying equipment (eg, conveying equipment provided in the treatment tank 2) included in the manufacturing equipment 10 for the polarizing film F1 out of the manufacturing equipment for the polarizing plate F described above.

[0026] Fig. 2 is a schematic diagram partially illustrating an example of a conveying facility to which the sheet passing method according to the present embodiment is applied. Fig. 2 illustrates a state in which the polarizing film F1 (including the original film F0 and the intermediate product film) after sheet passing is normally conveyed. 2, the conveying equipment 100 has a driving roller R1 and a driven roller R2. The driving roller R1 shown in FIG. 2 is disposed opposite the driven roller R2 in the horizontal direction (the left-right direction in FIG. 2), and the driving roller R1 and the driven roller R2 constitute a nip roller R.

[0027] FIG. 3 is an explanatory diagram showing a procedure for passing the polarizing film F1 through the pass line of the conveying equipment 100 shown in FIG. 2 using the passing method according to this embodiment. First, as shown in Fig. 3(a), the nip rollers R are opened. Specifically, the driven roller R2 of the nip roller R is moved in the direction of the arrow A while the driving of the drive roller R1 of the nip roller R is stopped.

[0028] Next, as shown in Fig. 3(b), the drive roller R1 is driven to rotate at a predetermined rotation speed in the direction of the arrow B. In order to enhance the safety and ease of the paper-passing operation, it is preferable to set the rotation speed of the drive roller R1 at this time to be equal to or lower than (the same as or smaller than) the rotation speed of the drive roller R1 during normal transport of the polarizing film F1 after paper passing (during the manufacture of the polarizing plate F) shown in Fig. 2. The rotation speed of the drive roller R1 during the paper passing operation, converted into the peripheral speed, is preferably 5 to 30 m / min, more preferably 5 to 20 m / min, and even more preferably 10 to 15 m / min.

[0029] Next, as shown in FIG. 3(c), while the drive roller R1 is rotating, a person manually pulls the leading end of the polarizing film F1 (the end on the right side in FIG. 3(c)) and wraps the polarizing film F1 around the leftmost driven roller R2, the driven roller R2 on the right of that, and the drive roller R1, in that order, so that the polarizing film F1 is aligned along the pass line PL (see FIG. 3(a)) determined by the positions of these three rollers. This completes the paper-passing operation up to the drive roller R1 of the conveying equipment 100. The pass line PL is an imaginary line determined by the position of each roller (drive roller R1 or driven roller R2) when the paper-passing operation is performed, and includes the common tangent of two adjacent rollers.

[0030] When the paper passing operation is completed as described above, the nip roller R is closed. Specifically, the driven roller R2 of the nip roller R is moved in the direction of the arrow C shown in Fig. 3(c) to contact the polarizing film F1. Then, as shown in Fig. 3(d), the polarizing film F1 is transported by the nip roller R. If a drive roller R1 or driven roller R2 is present downstream in the transport direction of the polarizing film F1 (not shown in Fig. 3), the paper will be passed through these rollers. When a person applies tension to the leading end of the polarizing film F1 by pulling it with his / her hand during the paper passing downstream in the transport direction, the drive roller R1 shown in Fig. 3 will also be driven to rotate.

[0031] According to the above-described paper-passing method of the present embodiment, when the polarizing film F1 is brought into contact with the driving roller R1 and the leading end of the polarizing film F1 is pulled by hand to apply tension, the driving roller R1 is driven and rotated, so that slippage of the polarizing film F1 against the driving roller R1 is suppressed, and the polarizing film F1 is less likely to be worn or cut. As a result, the polarizing film F1 is less likely to have poor appearance.

[0032] In the example described with reference to Fig. 3, the drive roller R1 is driven to rotate immediately after the nip roller R shown in Fig. 3(b) is opened. In other words, the drive roller R1 is driven before the polarizing film F1 is brought into contact with the drive roller R1. However, the present invention is not limited to this, and it is sufficient that the drive roller is rotating at least when the polarizing film F1 is brought into contact with the drive roller R1 and tension is applied to the leading end of the polarizing film F1. For example, even if the polarizing film F1 is wrapped around and in contact with the drive roller R1, it is not necessarily necessary to drive and rotate the drive roller R1 as long as the polarizing film F1 is not pulled (tension is not applied).

[0033] FIG. 4 is a schematic diagram partially illustrating an example of another conveying facility to which the sheet passing method according to the present embodiment is applied. The conveying equipment 100A shown in Fig. 4 also has a drive roller R1' and a driven roller R2, similar to the conveying equipment 100 shown in Fig. 2. However, unlike the drive roller R1 shown in Fig. 2, the drive roller R1' shown in Fig. 4 does not constitute a nip roller, and the drive roller R1' alone can convey the polarizing film F1 in the longitudinal direction. An example of such a drive roller R1' is a suction roller that conveys the polarizing film F1 while sucking it with negative pressure.

[0034] When the polarizing film F1 is passed through the pass line of the conveying equipment 100A shown in Fig. 4, while the driving roller R1' is rotating, a person manually pulls the leading end of the polarizing film F1 (the end on the right side of Fig. 4) and wraps the polarizing film F1 around the driven roller R2 and the driving roller R1' in that order, and aligns the polarizing film F1 with the pass line determined by the positions of these two rollers. This completes the paper passing operation up to the driving roller R1' of the conveying equipment 100A.

[0035] In addition, when the polarizing film F1 is passed through the pass line of the conveying equipment 100A shown in Figure 4, as in the case of the conveying equipment 100, it is sufficient that the drive roller R1' is rotating at least when the polarizing film F1 is brought into contact with the drive roller R1' to apply tension to the tip portion of the polarizing film F1. Moreover, the rotation speed of the drive roller R1' is preferably set to be equal to or lower than the rotation speed of the drive roller R1' during normal transport of the polarizing film F1 after paper feed (during the manufacture of the polarizing plate F). Furthermore, if drive rollers R1, R1' and driven roller R2 are present downstream in the transport direction of polarizing film F1 (not shown in Fig. 4), the paper will be passed through these rollers. When a person applies tension to the leading end of polarizing film F1 by pulling it with his / her hand during the paper passing downstream in the transport direction, the drive roller R1' shown in Fig. 4 will also be driven to rotate.

[0036] FIG. 5 is a schematic diagram partially illustrating an example of still another conveying facility to which the sheet passing method according to the present embodiment is applied. The conveying equipment 100B shown in Fig. 5 also has a driving roller R1 and a driven roller R2, similar to the conveying equipment 100 shown in Fig. 2 and the conveying equipment 100A shown in Fig. 4. The driving roller R1 shown in Fig. 5 is disposed opposite to the driven roller R2 in the vertical direction, and the driving roller R1 and the driven roller R2 form a nip roller R.

[0037] When the polarizing film F1 is passed through the pass line PL of the conveying equipment 100B shown in Fig. 5 using the paper passing method according to this embodiment, first, the nip rollers R are opened as shown in Fig. 5(a). Specifically, with the driving of the drive roller R1 of the nip rollers R stopped, the driven roller R2 of the nip rollers R is moved (lowered) in the direction of the arrow D.

[0038] Next, as shown in Fig. 5(b), while the driving roller R1 is stopped, a person manually pulls the leading end of the polarizing film F1 (the end on the right side in Fig. 5(b)) and wraps the polarizing film F1 around the leftmost driven roller R2, the middle driven roller R2, and the rightmost driven roller R2 in that order, and aligns the polarizing film F1 with the pass line PL (see Fig. 5(a)) determined by the positions of these three rollers. This completes the paper passing operation up to the rightmost driven roller R2 of the conveying equipment 100B.

[0039] When the paper passing operation is completed as described above, the nip roller R is closed. Specifically, the driven roller R2 of the nip roller R is moved (raised) in the direction of the arrow E shown in FIG. 5(c) to bring the polarizing film F1 into contact with the driving roller R1. The driving roller R1 is then driven to rotate in the direction of the arrow G at a predetermined rotational speed. Then, as shown in FIG. 5(d), the polarizing film F1 is transported by the nip roller R.

[0040] In the case of the conveying equipment 100B shown in Fig. 5 described above, the polarizing film F1 can be passed through simply by contacting the polarizing film F1 with the driven roller R2. In this case, it is possible to stop driving the driving roller R1 when the polarizing film F1 is passed through. In other words, since it is not necessary to bring the polarizing film F1 into contact with the driving roller R1 until the passing of the polarizing film is completed, it is possible to prevent the optical film from being worn or cut due to the optical film slipping against the stopped driving roller.

[0041] If a drive roller R1 or driven roller R2 exists downstream in the transport direction of the polarizing film F1 (not shown in Fig. 5), the paper will be passed through these rollers. When a person applies tension to the leading end of the polarizing film F1 by pulling it with his / her hand during the paper passing downstream in the transport direction, the drive roller R1 shown in Fig. 5 is driven to rotate.

[0042] In the above-described embodiment, the optical film is a polarizing film, but the present invention is not limited to this and can be applied to various other optical films. [Explanation of symbols]

[0043] 100, 100A, 100B...Transportation equipment R Nip roller R1, R1' Drive rollers R2: Driven roller F1···Polarizing film (optical film)

Claims

1. A method for passing an optical film through a pass line of a conveying facility having a drive roller and a driven roller opposed to the drive roller, which constitute a nip roller, comprising: When the optical film can be passed by simply contacting the optical film with the driven roller, the optical film is brought into contact only with the driven roller with the nip roller open, and the drive of the drive roller is stopped when the optical film is passed.

2. The method for passing an optical film according to claim 1 , wherein the optical film is a polarizing film.

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