JP2013208826A - Thin film printing method and thin film printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film printing method which enables high-quality and uniform printing on a functional thin film with less foreign matter, and to provide a thin film printer.SOLUTION: A thin film printer includes a cylinder-like plate cylinder equipped with a letterpress having a printing pattern formed on an outer circumferential part, an anilox roll for supplying an ink to the letterpress, an ink supply means, a doctor roll for scraping off a surplus ink on the anilox roll, and a positioning platen for placing a matter to be printed. A thin film printing method includes: (1) a doctoring step of supplying an ink to the anilox roll from the ink supply means and doctoring it means of a doctor roll; and (2) a step of supplying the doctored ink from the surface of the anilox roll to the surface of the letterpress, and then transferring the ink from the surface of the letterpress, to a matter to be printed. The steps (1) and (2) are performed in this order, at intervals. The operating velocities of the processes (1) and (2) are different and set independently of each other.

Description

  The present invention relates to a thin film printing method and a thin film printing apparatus, and more particularly to a printing method and a printing apparatus capable of printing various functional thin films with high quality.

  In recent years, attempts have been made to use a known printing method that is excellent in mass productivity and can reduce the manufacturing cost in forming a fine thin film pattern. In particular, in the display field, in order to cope with an increase in screen size and cost, studies are being made to form a functional thin film typified by an organic semiconductor or a conductive material by a printing method.

  As specific printing methods, an offset printing method, a gravure printing method, a gravure offset printing method, a relief printing method, and the like are being studied.

  Among these various printing methods, the resin letterpress printing method is a printing using a letterpress made of resin, an ink supply roll in which fine recesses (cells) are formed on the surface called anilox roll, and solvent-dried ink. This method is widely used as a flexographic printing method for printed materials such as packaging materials. This resin relief printing is particularly suitable for forming a thin film pattern having a film thickness of about 0.01 to 0.2 μm.

  The resin relief printing method allows printing at a very low printing pressure, called kiss touch, so printing on glass substrates and substrates on which transistor circuits, etc. whose characteristics are likely to be destroyed by applying high pressure are formed. The printing method is particularly suitable for pattern formation of electronic parts such as a display using such a substrate.

Next, a general letterpress printing apparatus will be described with reference to FIG.
As shown in FIG. 2, the letterpress printing apparatus includes an anilox roll (201) having cells for supplying ink to the plate surface of the letterpress (204), an ink chamber (208) for supplying ink to the anilox roll, and a plate. A rotary plate cylinder (205) on which a relief plate (204) for pattern formation is mounted via a lower cushion (203), a substrate surface plate (206) on which a substrate to be printed (207) is placed, and ink It has the structure which has a doctor blade (202) which performs the doctor ring which scrapes off.

Next, the flow of printing when using the printing machine of FIG. 2 will be described.
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) and the anilox roll (201) rotate in synchronization with the operation of the substrate surface plate (206). Thereafter, ink is supplied from the anilox roll (201) to the relief plate (204). Immediately after the ink is supplied to the relief plate (204), the ink on the relief plate is transferred to the printing substrate (207), and the printing operation is completed.

  Here, the doctor blade (202) is pressed against the anilox roll with high pressure in order to push the ink uniformly into the anilox roll cell by scraping off excess ink from the ink applied on the anilox roll (201). It is done. Since the surfaces operate with a strong force, both the anilox roll and the doctor blade are worn, and the scraped portion is mixed into the ink.

Since an anilox roll and a doctor blade are generally made of a metal, a metal oxide, or a resin, they are mixed into the ink as foreign matters. Foreign matter mixed in the ink finally remains in the printed film.

  This foreign matter is not a major problem if it is a general printed matter that has been the main target in the conventional resin letterpress printing method, but it is an electronic member such as fine patterning of functional thin films such as organic semiconductor thin films and conductive pastes. Direct printing results in defective products due to scraped foreign matter. In particular, when the foreign material is a metal, a problem such as short-circuiting occurs due to electrical conduction, and it is necessary to reduce the foreign material.

  As described above, a doctor blade is mainly used as a means for scraping off the ink on the anilox roll, but as shown in Patent Document 1, a doctor roll method using a rubber roll as a doctor as other means. Has also been used.

  By using the doctor roll method, it is possible to suppress the generation of foreign matter such as that generated by the doctor blade method, and therefore, it is considered suitable for printing for electronic members that dislike foreign matters.

JP 2001-083495 A

  As described above, by using the doctor roll method, it is possible to suppress the generation of foreign matters as generated by the doctor blade method.

  On the other hand, however, the doctor roll method has a problem in doctoring properties as compared with the blade method. That is, there is a limitation on the doctoring speed region where a good doctoring surface can be obtained. That is, in the doctor blade method, a good doctoring surface can be obtained regardless of the doctoring speed, whereas in the doctor roll method, a stable doctoring surface can be obtained only in a specific doctoring speed region.

  Therefore, in the conventional printing method in which the doctoring speed and the printing speed are constant, there is a problem that stable printing cannot be performed if the appropriate printing speed and the appropriate doctoring speed do not match.

  The problem to be solved by the present invention is to provide a thin film printing method and a thin film printing apparatus capable of solving such a problem in the doctor roll method and printing a functional thin film with few foreign matters with high quality and uniformity. is there.

  In order to solve the above-mentioned problems, the present inventor has conducted intensive research. As a result, a doctoring step of supplying ink from an ink supply means to an anilox roll and doctoring the supplied ink with a doctor roll, and the anilox roll After supplying the ink on the doctoring surface onto the relief printing plate, the transfer printing step for transferring the ink on the relief printing plate to the printing material is performed as an independent step, and the speed is arbitrarily set, thereby It can be performed at an appropriate speed that satisfies the demands of the ring process and the transfer printing process, and a good printed matter can be obtained.

Moreover, it was confirmed that the quality of the printed matter was improved by placing an arbitrary time between the doctoring process and the transfer printing process.

  As a means for solving the above-mentioned problems, the invention described in claim 1 is a thin film printing method, wherein a cylindrical plate cylinder having a relief plate on which a printing pattern is formed is provided on an outer peripheral portion. An anilox roll that supplies ink, an ink supply means that supplies ink to the anilox roll, a doctor roll that scrapes off excess ink on the anilox roll, and a positioning surface plate on which a printed material on which the ink on the relief printing plate is transferred is placed A step (1) of supplying ink from the ink supply means to the anilox roll using a printing apparatus, and doctoring the supplied ink with a doctor roll, and the doctored ink on the anilox roll is relief printing Step (2) of transferring the ink on the relief printing plate to the printing material after supplying the ink to the printing plate, with a time interval. A printing method of a thin film to perform in this order, and step (1), the behavior is different speed in step (2), and a thin film printing method and sets independently.

  The invention according to claim 2 is the thin film printing method according to claim 1, wherein a time interval from the step (1) to the step (2) is arbitrarily selected.

  The invention according to claim 3 is a thin film printing apparatus, comprising a cylindrical plate cylinder having a relief plate having a printing pattern formed on its outer peripheral portion, an anilox roll for supplying ink to the relief plate, an anilox roll An ink supply means for supplying ink to the paper, a doctor roll for scraping off excess ink on the anilox roll, and a positioning platen for placing a printed material to which the ink on the relief printing plate is placed, from the ink supply means A step (1) of supplying ink to the anilox roll and doctoring the supplied ink with a doctor roll; and after supplying the doctored ink on the anilox roll onto the relief plate, the ink on the relief plate is printed A thin-film printing apparatus that performs steps (2) and (2) in this order at intervals of time, A thin film printing apparatus, characterized in that the operating speed to be set independently in the step (2).

  According to a fourth aspect of the present invention, in the thin film printing apparatus according to the third aspect, the time interval from the step (1) to the step (2) can be arbitrarily set. is there.

  According to the thin film printing method and the thin film printing apparatus according to the present invention, it is possible to obtain a uniform functional thin film that does not include foreign matters in the printed matter and has no unevenness.

  Moreover, since the optimal relaxation time can be given to the ink film on an anilox roll by selecting arbitrarily the time interval from process (1) to process (2), a more uniform thin film is obtained. .

FIG. 1 is a schematic view showing the structure of a thin film printing apparatus according to the present invention. FIG. 2 is a schematic view showing the structure of a conventional relief printing apparatus having a doctor blade.

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

  An embodiment of the present invention will be described focusing on an ink supply means (109) having an anilox roll (101) and a doctor roll (102) in the thin film printing apparatus shown in FIG. The thin film printing apparatus shown in FIG. 1 includes a cylindrical plate cylinder (105) on which a relief printing plate (104) for pattern formation is mounted, an anilox roll (101) for supplying ink in contact with the relief printing plate (104), and ink on the anilox roll. Printing apparatus comprising an ink chamber (108) for supplying, a doctor roll (102) for scraping off excess ink on the anilox roll (101), and a substrate surface plate (106) on which a substrate to be printed (107) is placed It is.

  As an anilox roll (101) that can be used in the thin film printing method of the present invention, a chromium oxide film formed by plasma spraying chromium oxide on a core roll made of a stainless steel (SUS) material or the like is used as a laser. A ceramic roll patterned by engraving and a chrome plating roll with copper plating on the core roll, then applying a photosensitive resin, laser patterning and then corrosion treatment, and chrome plating on the resulting concavo-convex pattern Any of these can be used.

  In addition, as a pattern formed on the anilox roll, a helical pattern, FM pattern, honeycomb pattern, diamond pattern, etc. can be used, but an APEX GTT pattern or plastic square that can be expected to flow inside the cell. An engineering company's ART pattern is most suitable.

  These patterns may be appropriately angled to prevent moire. Further, the density (number of lines) at which the pattern is formed is determined by the fineness of the actually printed pattern, but it is preferably about 700 lines or more per inch.

  After these patterns are formed, the surface of the anilox roll (101) is preferably 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 speed with high accuracy because uneven rotation speed greatly affects printed matter. Further, when a speed reduction mechanism is used to obtain a required torque, it is desirable to use a gear box having a backlash-less mechanism.

  Next, as a doctor roll (102) that can be used, 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, A rubber roll created by wrapping ethylene propylene rubber, urethane rubber or the like may be used, or a roll of PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) heat shrinkable tube wound around these rubber rollers. I can do it. These rubber materials and surface coating materials are selected based on the resistance to the ink solvent.

  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 smooth doctoring surface can be obtained.

  Next, as the hardness of the doctor roll (102) that can be used, any of the JIS-A hardnesses in the range of 30 ° to 70 ° can be used.

As a mechanism for rotating the doctor roll (102), it is possible to use the anilox roll as a rotating mechanism. However, if you want to rotate with high accuracy, use a servo motor that can control the rotation speed with high accuracy and use direct drive. It is desirable to do this, and it is desirable to have a system that can be controlled in a manner that can be synchronized with the rotation of the anilox roll.

  Next, installation of the anilox roll (101) and the doctor roll (102) will be described. In the doctor roll method, the doctor roll (102) is pressed against the anilox roll (101) with an arbitrary pressure. The range of pressure to be pressed is set so that the contact surface pressure is 0.3 MPa to 0.7 MPa. By setting it within this range, it is possible to suppress good doctoring properties and generation of foreign matter.

  As the pressing mechanism, a mechanism that combines reproducibility and an air cylinder capable of arbitrarily setting the pressing force and a linear guide is desirable.

  The pressing position is preferably below the anilox roll center line. By installing below the center line, the doctored excess ink can return to the ink chamber properly.

Next, the actual operation when this printing apparatus is used will be described.
After the substrate to be printed (107) such as a glass substrate is placed on the substrate surface plate (106), a series of printing operations is started by an operation start instruction.

  After an instruction to start printing is given, the doctoring process is started first. The doctoring process is performed by first supplying ink from the ink chamber (108) onto the anilox roll (101), and then the doctor roll (102) scrapes off excess ink. The peripheral speed at the time of doctoring is arbitrarily determined according to the ink and the doctoring state. That is, it is determined in consideration of physical properties such as the viscosity and surface tension of the ink to be used and the actual doctoring state.

  The doctoring state on the anilox roll (101) is roughly determined by using a method of observing the surface of the anilox roll that has been dried after doctoring and the condition of generation of streaks by visual confirmation during doctoring. The transfer operation is actually performed under conditions that allow good doctoring, and finally the optimum doctoring speed is determined by various evaluation means.

  After the doctoring process is completed, a transfer printing process is performed. An arbitrary relaxation time is provided between the doctoring process and the transfer printing process. By providing time between the doctoring process and the transfer printing process, it is possible to expect the effect of alleviating streaks and unevenness caused by the doctoring.

  The actual relaxation time varies depending on the viscosity of the ink used, but the effect is remarkably confirmed in about 10 seconds or more. On the other hand, if the relaxation time is too long, the anilox roll surface is dried, and unevenness due to drying is newly generated. Since the relaxation time varies greatly depending on the boiling point of the solvent and the presence or absence of the anilox roll cover, the relaxation time is determined and determined each time.

  Next, after the substrate surface plate (106) is moved directly below the plate cylinder, ink is supplied onto the plate from the anilox roll (101), and then the substrate placed on the substrate surface plate (106) synchronized with the rotation of the plate cylinder. A transfer printing process for transferring to the printed circuit board (107) is performed.

The peripheral speeds of the step of supplying ink from the anilox roll (101) onto the plate and the step of transferring from the plate to the printing substrate (107) are the same, and the speed can be arbitrarily selected. By changing the transfer printing speed, it is possible to adjust printing characteristics such as increase / decrease in ink transfer amount, increase / decrease in line width, and the like.

  As described above, by arbitrarily selecting the doctoring speed and the transfer speed, it is possible to select the optimum speed in the doctoring process and the transfer printing process, respectively, and obtain a desired high-quality printed matter. I can do it. Hereinafter, the thin film printing method and the thin film printing apparatus according to the present invention will be described more specifically based on examples. It should be noted that the present invention is not limited to the examples, and improvements, modifications, and the like within a scope that can achieve the object of the present invention do not depart from the spirit of the present invention.

  In this embodiment, an example is shown in which a polymer type organic light emitting material is printed on a raw glass, and unevenness and variation in the amount of printing transition are evaluated.

  A printing apparatus having the structure shown in FIG. 1 was used as the printing apparatus. As an anilox roll, a chromium plating roll having a surface length of 200 mm and a diameter of 80 mm was used. The pattern formed on the roll is a dot pattern in which circular dots having a diameter of 14.5 μm are formed at a pitch of 35 μm. The aforementioned pattern is formed over the entire peripheral surface of the anilox roll.

  As a doctor roll used in this example, urethane rubber having a hardness of JIS-A 50 ° was wound around a SUS core having a diameter of 30 mm, and processed into a columnar shape having a diameter of 50 mm. After winding the PFA heat shrinkable tube on the processed urethane rubber roll, polishing was carried out so that Ra was 0.05 μm and Rz was 1 μm.

  The doctor roll was installed in such a manner that it was pushed into the anilox roll at a nip pressure of 0.4 MPa. The installed anilox roll and doctor roll are each driven by a servo motor and controlled so that their peripheral speeds coincide with each other.

  Next, the plate material used will be described. A black oil dye was applied to the surface of a SUS304 steel 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 to the surface of this laminate so that the total thickness was 100 μm, and used as the base of the plate.

  Thereafter, a negative pattern (effective area opening 106 μm * 100 mm, non-opening space 392 μm * 100 mm, total number of effective lines 400, size W200 mm, L100 mm) is applied to the plate material using a chromium mask of 50 μm. The exposure gap was opened. 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 affixed to the plate cylinder of a printing apparatus 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 polymer organic light emitting material, in 4-methylanisole 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 chamber of the printing apparatus.

Printing was performed on soda glass subjected to UV / O ₃ treatment using the above-described apparatus, plate, and luminescent material ink. Printing was performed at a doctoring speed of 5 mm / s and a printing speed of 100 mm / s.

  In Example 2, the doctoring speed was 150 mm / s, and a relaxation time of 30 seconds was taken between the doctoring process and the transfer printing process. Otherwise, printing was performed in the same manner as in Example 1.

<Comparative Example 1>
Printing was performed in the same manner as in Example 1 except that the printing speed in Example 1 was set to 5 mm / s, which was the same as the doctoring speed.

<Comparative example 2>
Printing was performed in the same manner as in Example 2, except that the relaxation time in Example 2 was not set to 0 second.

In Examples 1 and 2 and Comparative Examples 1 and 2, the following evaluation was performed on the glass substrate on which the organic light emitting layer was formed.
1. Measurement of variation in cross-sectional area of printing transition amount on the printing surface (5 points in the surface: standardized in the center)
Approximately 10% or less is within a variation range that does not affect the element characteristics.
2. Variation in brightness when PL light emission of printed matter on raw glass is captured with a UV light source scanner,
Also, the evaluation of specific unevenness is within a variation range that does not affect the element characteristics at about 10% or less.

The evaluation results are shown in Table 1.

  From the results of Table 1, in Examples 1 and 2, the variation in the amount of printing transition and the variation in light emission luminance were within the allowable range, and the printing unevenness and the like were good results. On the other hand, in Comparative Example 1, both the transfer amount and the light emission luminance varied greatly, and coating unevenness occurred. In Comparative Example 2, the variation in the transfer amount was within the allowable range, but the variation in the light emission luminance was large, and coating unevenness was also observed.

101, 201 ... Anilox roll 102 ... Doctor roll 103, 203 ... Underlay cushion 104, 204 ... Top plate 105, 205 ... Plate cylinder 106, 206 ... Substrate surface plate 107, 207 ... Printed substrates 108, 208 ... Ink chamber 109 ... Ink supply means 202 ... Doctor blade

Claims (4)

A thin-film printing method comprising a cylindrical plate cylinder having a relief printing plate with a printing pattern formed on its outer peripheral part, an anilox roll for supplying ink to the relief printing plate, an ink supply means for supplying ink to the anilox roll, an anilox roll Using a printing apparatus comprising a doctor roll that scrapes off excess ink on the upper surface, and a positioning surface plate on which a printed material onto which the ink on the relief printing plate is transferred is placed,
(1) supplying ink to the anilox roll from the ink supply means and doctoring the supplied ink with a doctor roll; and supplying the doctored ink on the anilox roll onto the relief plate; The thin film printing method in which the step (2) of transferring the ink to the substrate to be printed is performed in this order at time intervals, and the operation speeds in the step (1) and the step (2) are different and independent. A thin film printing method, characterized by being set to   The thin film printing method according to claim 1, wherein a time interval from the step (1) to the step (2) is arbitrarily selected. A thin-film printing apparatus, a cylindrical plate cylinder having a relief printing plate with a printing pattern formed on its outer periphery, an anilox roll for supplying ink to the relief printing plate, an ink supply means for supplying ink to the anilox roll, an anilox roll A doctor roll that scrapes off the excess ink on the upper surface, and a positioning surface plate on which a printed material on which the ink on the relief printing plate is transferred is placed;
(1) supplying ink to the anilox roll from the ink supply means and doctoring the supplied ink with a doctor roll; and supplying the doctored ink on the anilox roll onto the relief plate; Is a thin film printing apparatus in which the step (2) of transferring the ink to the substrate to be printed is performed in this order at time intervals, and the operation speeds in the step (1) and the step (2) can be set independently. A thin film printing apparatus characterized by the above.   The thin film printing apparatus according to claim 3, wherein a time interval from the step (1) to the step (2) can be arbitrarily set.