JP2014168919A - Functional thin film forming printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a functional thin film forming printer capable of printing a functional thin film with high quality and few foreign substances, and consequently, improving uniformity of light emission.SOLUTION: A functional thin film forming printer includes: a cylinder type plate cylinder 105 mounted with a pattern forming flexographic plate 104; an ink supply mechanism 109 comprising an anilox roll 101 contacting the flexographic plate 104 to supply ink, an ink chamber 108 for storing ink to be supplied to the anilox roll 101, and a doctor roll 102 for scraping off excess ink on the anilox roll 101; and a substrate surface plate 106 to place a substrate 107 thereon. The doctor roll includes an angle adjustment mechanism 102a so as to be adjusted to have an inclination angle in a twisting direction to the anilox roll.

Description

  TECHNICAL FIELD The present invention relates to a functional thin film forming printing apparatus for printing a functional thin film with high quality. Specifically, when forming an organic electroluminescence (hereinafter referred to as organic EL) element, the uniformity of light emission is particularly improved. The present invention relates to an improved printing apparatus.

  Efforts have been made to develop a new device by forming a fine pattern by a printing method that is excellent in inexpensive manufacturing cost and mass productivity. In particular, in the display field, an attempt is made to form a functional thin film with a fine pattern by a printing method as a technique for achieving both production efficiency and large area.

  As printing methods currently under development, applications such as ink jet printing, nozzle printing, offset printing, gravure printing, gravure offset printing, letterpress printing (flexographic printing) are being studied.

  Among the various printing methods, the flexographic printing method, in particular, supplies ink to the surface of the flexographic plate with a flexographic plate made of a photosensitive resin and an ink roll called an anilox roll with regular irregularities formed on the surface. The printing method to be formed. Flexographic printing is used for printing corrugated cardboard liners, packaging films, and the like, and is particularly suitable for forming a thin and stable printing layer having a thickness of about 0.01 to 0.2 μm.

  Flexo printing allows printing at a very low printing pressure, which is called kiss touch with almost no printing pressure, so its characteristics can be achieved by applying an extremely thin glass substrate used for electronic parts such as displays and high printing pressure. It is also suitable for printing on a substrate on which a transparent electrode such as ITO that is easily destroyed is formed.

  Next, a general flexographic printing apparatus will be described with reference to FIG. This flexographic printing apparatus includes an anilox roll 201 having a cell for supplying ink to a plate surface of a flexographic plate 204, an ink chamber 208 for supplying ink to the anilox roll, and a plate-forming cushion 203 to form a flexographic plate for pattern formation. A rotary plate cylinder 205 to which 204 is mounted, a substrate surface plate 206 on which a substrate to be printed 207 is placed, and a doctor blade 202 that performs doctoring to scrape off ink.

  Next, a printing flow will be described with reference to FIG. First, after the substrate to be printed 207 is placed on the substrate surface plate 206, it moves to just below the plate cylinder 205. When the substrate surface plate 206 moves, the plate cylinder 205 rotates in synchronization with the operation of the substrate surface plate 206, and ink is supplied to the flexographic plate 204 from the anilox roll 201 operating at the same speed as the plate cylinder 205. After the ink is supplied to the flexographic plate 204, the flexographic ink is quickly transferred to the printing substrate 207 and the printing operation is completed.

  Here, the doctor blade 202 is generally pushed to the anilox roll with a pressure of about 20 kPa in order to uniformly push the ink into the anilox roll cell by scraping off excess ink from the ink applied on the anilox roll 201. Hit. For this reason, both the anilox roll and the doctor blade are worn, and there is a problem that the scraped portion (scraped foreign matter) is mixed into the ink.

Since an anilox roll and a doctor blade are generally made of a metal oxide or a resin, they are mixed into the ink as foreign matters.

  In the conventional flexographic printing method, the foreign matter is not a big problem if it is a general printed matter, but in the printing for electronics members for the purpose of fine patterning of functional thin films such as organic semiconductor thin films and organic EL thin films. A defect such as a short circuit due to electrical conduction occurs due to a metal foreign object that has been cut off, resulting in a product defect.

  As described above, as a means for scraping off the ink on the anilox roll, a doctor blade method using a doctor blade is mainly used. However, as shown in Patent Document 1, rubber or the like is processed into a roll shape. The doctor roll technique used as an alternative to the doctor blade is also used.

  By using the above doctor roll as a substitute for the doctor blade in the flexographic printing method and realizing uniform doctoring, it is possible to easily form a printing pattern with a uniform film thickness without generating metallic foreign objects. It has become possible to develop various applications such as fine patterning technology for electronic components.

  However, the use of the doctor roll method can suppress the generation of metallic foreign objects such as those generated by the doctor blade method, but the scratching property is inferior when compared to the doctor blade method, and the scratching property in the central region of the anilox roll is poor. However, the amount of ink in the central region is excessive, and there are problems such as the occurrence of unevenness in the central region of the printed matter and the ink adhering to areas other than the pattern portion of the plate.

JP 2001-083495 A

  In order to solve the above-mentioned problems, the present inventor has intensively studied and investigated the cause of the occurrence of the liquid scraping failure in the central region of the anilox roll when performing the liquid scraping using the doctor roll. FIG. 2 is a diagram illustrating the cause of the occurrence of liquid scraping failure in the central region of the anilox roll. 2A shows a top view and FIG. 2B shows a side view. When the doctor roll 301 is pressed against the bearing from the direction indicated by 303, the doctor roll 302 is bent at the portion 304 that contacts the anilox roll 301 and the center portion escapes from the anilox roll 301. It became clear that was the cause.

  Accordingly, the object of the present invention is to solve the above-mentioned problems that occur when the anilox roll surface is scraped with the doctor roll, and to print the functional thin film with high quality and less foreign matter, thereby improving the uniformity of light emission. It is an object of the present invention to provide a functional thin film forming printing apparatus that can be made to operate.

Therefore, the invention described in claim 1 of the present invention is
A functional thin film forming printing device for forming a functional thin film on a substrate,
A plate cylinder and an ink supply mechanism;
The plate cylinder is in the form of a cylinder having a relief plate with a printing pattern formed on the outer periphery,
The ink supply mechanism is composed of an ink chamber for storing ink, an anilox roll for supplying ink to the letterpress, and a doctor roll that presses the anilox roll and scrapes off excess ink on the anilox roll surface.
The doctor roll is a functional thin film forming printing apparatus provided with an angle adjusting mechanism so as to have an inclination angle in the direction of twist with respect to the anilox roll.

The invention according to claim 2 of the present invention provides
2. The functionality according to claim 1, wherein the angle adjusting mechanism lowers one of the bearings of the doctor roll downward, raises the other one of the bearings upward, and the amount of the raising / lowering is the same. A printing apparatus for forming a thin film.

  According to the printing apparatus for forming a functional thin film of the present invention, by using a doctor roll, it is possible to prevent generation of metallic foreign matters when using a doctor blade. In addition, by adjusting the angle of the doctor roll so as to be inclined with respect to the anilox roll, it is possible to prevent liquid scraping failure at the central region of the anilox roll, and to easily form a print pattern with a uniform film thickness. Can do. As a result, it is possible to form an organic EL element that prints a functional thin film with high quality and less foreign matter and improves the uniformity of light emission.

The figure explaining the outline of the flexographic printing apparatus which has a conventional doctor blade. The figure explaining the bending of the roll at the time of pressing a doctor roll to the conventional anilox roll. (A) is a top view. (B) is a side view. The figure explaining the outline of the printing apparatus for functional thin film formation which has a doctor roll which concerns on this invention. Explanatory drawing of the angle adjustment mechanism with which the doctor roll which concerns on this invention was equipped. (A) is a top view. (B) is a side view. The figure for demonstrating in detail the angle adjustment mechanism with which the doctor roll which concerns on this invention was equipped. (A) is a top view. (B) is a side view. The figure which shows the flow in the case of adjusting the angle of a doctor roll with the angle adjustment mechanism which concerns on this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Note that. The present invention is not limited to this.

  FIG. 3 is a diagram showing a schematic configuration of the functional thin film forming printing apparatus of the present invention. The functional thin film forming printing apparatus shown in FIG. 3 has a cylindrical plate cylinder 105 on which a flexographic plate 104 for pattern formation is mounted, an anilox roll 101 for supplying ink in contact with the flexographic plate 104, and an anilox roll 101. An ink supply mechanism 109 and a substrate surface plate 106 on which a substrate 107 is placed are provided from an ink chamber 108 for storing ink to be stored and a doctor roll 102 for scraping off excess ink on the anilox roll 101. The doctor roll is provided with an angle adjusting mechanism 102a and is adjusted so as to have an inclination angle with respect to the anilox roll.

As an anilox roll 101 that can be used for flexographic printing of the present invention, ceramics obtained by patterning a chromium oxide film formed by plasma spraying chromium oxide on a core roll made of a SUS material or the like by laser engraving Either a roll or a core roll, after copper plating is applied, a resin is applied, laser patterning is performed, and then a corrosion treatment is performed.

  Further, as a pattern formed on the aniloc roll, any pattern such as a helical pattern, an FM pattern, a honeycomb pattern, a diamond pattern, and an ART pattern can be used.

  These patterns may be appropriately angled to prevent moire on the printed material. After these patterns are formed, the surface of the anilox roll 101 is desirably polished to prevent scratching the doctor roll 102 side. Specifically, it is desirable that the anilox roll pattern is polished so as to eliminate protrusions of 4 μm or more. As a mechanism for rotating the anilox roll 101, it is desirable to perform direct drive with a servo motor capable of controlling the rotation with high accuracy because uneven rotation speed greatly affects the printed matter. Further, when using a speed reduction mechanism to obtain the required torque, it is desirable to use a backlashless mechanism.

  Doctor roll 102 that can be used is a core roll made of SUS material, etc., nitrile rubber, silicone rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, butyl rubber, acrylonitrile rubber, ethylene propylene rubber, urethane It may be created by wrapping rubber or the like, or a material in which a PFA heat shrinkable tube is wound on these rubber rollers can be used. These rubber materials are selected from the resistance to the solvent used as the ink. The surfaces of these rubber rolls preferably have an arithmetic surface roughness Ra of 0.1 μm or less and a maximum height Rz of 1 μm or less. By satisfying these conditions, a low dust generation and a smooth liquid scraping surface can be obtained.

  For the formation of the surface of the doctor roll 102, fluororesin powder spray coating such as PTFE and PFA, spray coating, formation of a fluororesin film such as plasma polymerization, or vapor deposition of a surface modifier having a perfluoroalkyl chain, etc. It can be prepared using a known method for forming a fluorinated monomolecular film.

  As the hardness of the doctor roll 102 that can be used, any can be used in the range of 30 ° to 70 ° in terms of JIS-A hardness.

  As the mechanism for rotating the doctor roll 102, it is desirable to use a servo motor that can control the rotation with high precision, since the uneven rotation speed has a large effect on the printed matter, and it is desirable to perform direct drive and synchronize with the rotation of the anilox roll. It is desirable to have a system that can be controlled in a rotatable manner.

  As shown in FIG. 2, the doctor roll 302 is pressed at the both ends of the doctor roll in the direction indicated by reference numeral 403, and when the doctor roll 302 is pressed against the anilox roll 301, the contact part 304 with the anilox roll serves as a fulcrum. Will bend in the direction of escaping from the anilox roll. Therefore, in the present invention, the doctor roll 402 as shown in FIG. 4 is provided with an angle adjusting mechanism 102a including angle adjusting portions 102a-1 and 102a-2 so as to have an inclination angle in the direction of twist with respect to the anilox roll 401. It has been. By giving the doctor roll 402 an angle with respect to the anilox roll 401, the vicinity of the center of the doctor roll 402 can be pressed against the anilox roll, and both ends can be pressed against the anilox roll without bending. As a result, the liquid scraping defect in the central region of the anilox roll 401 can be eliminated.

  The doctor roll 402 can be manufactured by selecting the rubber hardness and the surface material by the same method as the anilox roll 401. The inclination of the doctor roll 402 is preferably set in a range of 2 ° to 5 ° with respect to the anilox roll 401. By tilting the doctor roll 402 within this range, the doctor roll 402 is made uniform over the entire width direction of the anilox roll 401. Can be pressed against. When tilted beyond this range, the both end regions of the anilox roll 401 are not pressed against the doctor roll 402 and the ink cannot be scraped off.

  5A and 5B are diagrams for explaining the angle adjusting mechanism 102a in detail. FIG. 5A is a top view and FIG. 5B is a side view. FIG. 6 is a diagram showing a flow when the angle of the doctor roll 402 is adjusted by the angle adjusting mechanism 102a. A flow in the case of adjusting the angle of the doctor roll 402 by the angle adjusting mechanism 102a will be described with reference to FIGS.

  First, as shown in FIG. 5A, with the anilox roll 401 and the doctor roll 402 in parallel, the bearings 405 and 406 at both ends of the doctor roll 402 are pushed in the direction of the arrow 403, so that the doctor roll 402 is moved to the anilox roll 401. Press (S1). The strength of pressing may be such that the doctor roll 402 is in contact with the anilox roll 401.

  Next, after the bearing 405 at the left end of the doctor roll 402 is lowered downward as indicated by the arrow 500-1 by the angle adjustment unit 102a-1 (S2), the bearing at the right end of the doctor roll 402 is then moved by the angle adjustment unit 102a-2. 406 is raised upward as indicated by arrow 500-2 (S3). In this case, the amount to be lowered below the left end bearing 405 and the amount to be raised above the right end bearing 406 are the same. By doing so, the doctor roll 402 can be tilted in a state where the center portion in the width direction of the doctor roll 402 and the center portion of the anilox roll 401 are in contact with each other. In this case, the amount of control for lowering and raising upward can be accurately achieved by using, for example, a linear encoder. Moreover, the control result can be confirmed by displaying the control amount.

  Thereafter, the bearings 405 and 406 at both ends of the doctor roll 402 are further pressed in the direction of the arrow 403 to press the doctor roll 402 against the anilox roll 401 (S4). As a result, the doctor roll 402 can be pressed over the entire width of the anilox roll 401. The order of the steps (S2) and (S3) may be reversed. Moreover, you may abbreviate | press pressing the doctor roll 402 in step (S4) by fully pushing in step (S1).

  The operation of the functional thin film forming printing apparatus according to the present invention will be described with reference to FIG. 3 showing the functional thin film forming printing apparatus according to the present invention. After placing the glass substrate 107 on the substrate surface plate 106, a printing operation is started by a print start instruction. During this time, ink is supplied onto the anilox roll 101 and doctoring is continuously performed, so that a smooth doctored surface is always held. Next, after the substrate surface plate 106 is moved directly below the plate cylinder 105, the ink is transferred onto the plate from the anilox roll 101, and then the glass placed on the substrate surface plate 106 conveyed in synchronization with the rotation of the plate cylinder. Printing is performed on the substrate 107.

<Example>
Examples of the present invention will be described. In addition, this invention is not limited to an Example, The improvement, deformation | transformation, etc. in the range which can achieve this invention do not deviate from the meaning of this invention.

  In this embodiment, a case where a polymer type organic light emitting material is printed on a glass substrate is shown.

  As a printing machine, the functional thin film forming printing apparatus shown in FIG. 3 is used.

  A chrome roll was used as the anilox roll 101 used in this example. The pattern formed on the roll is a diamond pattern in which square cells each having a side of 65 μm are formed at a pitch of 72.5 μm, and these patterns are formed inclined by 60 ° from the horizontal line of the roll.

  Next, as the doctor roll 102 used in this example, urethane rubber having a hardness of JIS-A 50 ° was wound on a SUS core and processed into a columnar shape so as to be within 0.5 mm with respect to the target diameter. Further, after winding a PFA heat shrinkable tube on the processed urethane rubber roll, polishing of the entire roll peripheral surface was carried out so that Ra was 0.05 μm and Rz was 1 μm. The length of the doctor roll 102 was made to be 10 mm longer than the total length of the anilox roll so that the ink on the anilox roll could be scraped with the full width. The doctor roll was installed in the form of pushing in by 50 μm to the anilox roll 101. The installed anilox roll was rotated while being controlled by a servo motor, and the doctor roll was rotated around the anilox roll for doctoring.

  Next, the plate material of the relief plate 104 used will be described.

  A black oil-based dye was applied to the surface of a SUS304 plate having a thickness of 0.2 mm as a reflection suppressing layer by a die coating method so as to have a thickness of 1.5 μm. A negative photosensitive resin mainly composed of polyamide was applied on the surface of this laminate so that the total thickness was 0.1 mm, and used as a base of the plate.

  Thereafter, a 50 μm proxy is applied to the plate material using a chromium mask having a negative pattern (effective area opening 106 μm * 100 mm, non-opening space 392 μm * 100 mm, total effective line number 400, size W200 mm L100). It was exposed with a Mitty gap. After the exposure, development was performed while pouring warm water to form a relief plate having a convex portion height of 90 μm, a convex portion line width of 106 μm, and a space of 392 μm. The prepared relief plate was attached to the plate cylinder of a printing machine using a printing cushion tape having a thickness of 0.5 mm.

  Next, the ink will be described.

  An organic light-emitting ink was prepared by dissolving a polyphenylene vinylene derivative, which is a high-molecular organic light-emitting material, in anisole so as to have a concentration of 2%. When the viscosity of the prepared ink was measured, it was 60 mPa · s, and the surface tension was 34 mN / m. Thereafter, the ink was put into the ink chamber 108 of the printing press.

  Printing was performed on soda glass having a size of 300 mm square and a thickness of 0.7 mm using the above printing apparatus, plate, and luminescent material ink. Printing was performed at a cycle time of 60 s, the doctoring speed was 5 mm / s, and the printing speed was 100 mm / s.

<Comparative example>
In the functional thin film forming printing apparatus used in the example, the angle adjusting mechanism 102a is not used, and the other conditions are the same as those in the example.

The following evaluation was performed about the board | substrate with which the organic light emitting layer obtained in the Example was formed.
(Evaluation item 1) Check for ink adhesion other than the pattern area of the plate (visual confirmation)
(Evaluation item 2) Uneven evaluation of the entire printed pattern (visual confirmation)
(Evaluation item 3) Measurement of variation in ink film thickness in the width direction of the glass substrate printed on the glass substrate

  In the examples, evaluation was performed by measuring variations in the amount of ink transferred in the printing width direction after printing. In the case where the angle adjustment mechanism 102a is not provided, the distribution amount distribution in the width direction is ± 15%, but in the printed matter obtained by the printing machine according to the present invention using the angle adjustment mechanism 102a, the target value is ± 5%. It was within the range of the variation considered to be non-defective. Also, no specific unevenness was observed.

  The printing apparatus for forming a functional thin film that prevents the ink scraping failure due to the bending of the doctor roll according to the present invention by the angle adjusting mechanism 102a is not limited to the above-described functional thin film formation, and the doctor roll is used to form the anilox roll surface. The present invention can be widely applied to printing apparatuses that supply ink by doctoring.

101 ... Anilox roll 102 ... Doctor roll 102a ... Angle adjustment mechanism 102a-1, 102a-2 ... Angle adjustment unit 103 ... Underlay cushion 104 ... Flexo plate 105 ... Plate Cylinder 106 ... Substrate surface plate 107 ... Printed substrate 108 ... Ink chamber 109 ... Ink supply mechanism 201 ... Anilox roll 202 ... Doctor blade 203 ... Underlay cushion 204 ...・ Flexo plate 205 ... Plate cylinder 206 ... Substrate surface plate 207 ... Print substrate 208 ... Ink chamber 301 ... Anilox roll 302 ... Doctor roll 303 ... Doctor roll bearing portion Pushing direction 304... Contact point 401 between the anilox roll and the doctor roll 401... Anilox roll 402. Doctor roll 403 provided with an angle adjustment mechanism ... Direction 404 for pushing the doctor roll bearing portion ... Direction 405, 406 ... for pushing the anilox roll by the doctor roll Bearings 501, 502 ... at both ends of the doctor roll 402 Direction in which the bearings at both ends of the doctor roll 402 are moved up and down by the angle adjustment unit

Claims (2)

A functional thin film forming printing device for forming a functional thin film on a substrate,
A plate cylinder and an ink supply mechanism;
The plate cylinder is in the form of a cylinder having a relief plate with a printing pattern formed on the outer periphery,
The ink supply mechanism is composed of an ink chamber for storing ink, an anilox roll for supplying ink to the letterpress, and a doctor roll that presses the anilox roll and scrapes off excess ink on the anilox roll surface.
A functional thin film forming printing apparatus, wherein the doctor roll is provided with an angle adjusting mechanism so that the doctor roll has an inclination angle in a twisting direction with respect to the anilox roll.   2. The functionality according to claim 1, wherein the angle adjusting mechanism lowers one of the bearings of the doctor roll downward, raises the other one of the bearings upward, and the amount of the raising / lowering is the same. Printing device for thin film formation.