JP2014162020A - Doctor roll, letterpress printing machine, organic el panel manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a doctor roll which suppresses the generation of foreign matters during the doctoring process and has high doctoring performance, a letterpress printing machine using the same, and an organic EL panel manufacturing device that can produce a high-quality polymer organic EL panel at a low cost with this printing machine.SOLUTION: In a letterpress printing machine device comprising a machine platen mounting a printing target substrate, a rotary plate cylinder that has a letterpress installed thereon and is arranged on the machine platen, an anilox roll arranged to face the plate cylinder, an ink chamber that houses a part of the anilox roll to supply ink to the anilox roll, and a doctor roll provided to scrape off the ink supplied onto the anilox roll, the doctor roll of the letterpress printing machine is characterized in that the hardness of the peripheral surface part at both ends is made smaller than the hardness of the peripheral surface part in a central part.

Description

  The present invention relates to an apparatus for producing a polymer organic EL panel by printing on a substrate an ink obtained by dissolving a polymer organic EL (electroluminescence) material in a solvent, a printing machine used for the apparatus, In particular, it relates to a doctor roll used therein.

2. Description of the Related Art In recent years, organic EL elements having features such as thinness, low power, and high luminance display have attracted attention as display elements in mobile phones, PDAs (personal digital assistants), mobile personal computers, in-vehicle navigation systems, and the like.
In this organic EL element, for example, an anode (transparent conductive film, ITO film), a light emitting layer containing an organic light emitter, and a cathode (metal electrode) are laminated on a transparent substrate.

The light emitting layer of the organic EL element is usually formed by vacuum vapor deposition of a low molecular organic light emitter. In this case, there is a limit to the increase in size of the organic EL element due to the principle of the vapor deposition apparatus.
In view of this, attempts have been made to form a light emitting layer by a known printing method by dissolving a polymer organic light emitting material in a solvent and dispersing it into an ink (see, for example, Patent Documents 1 and 2).
This printing method is excellent in mass productivity and can reduce the manufacturing cost. Specific printing methods include offset printing and gravure printing.

  Flexographic printing is a printing method using a flexible relief printing plate made of rubber or resin, an inking roll called a anilox roll with engraved fine recesses on the surface, and solvent-drying ink. Widely used for printing simple prints. This flexographic printing is particularly suitable for forming a thin and stable printing layer having a film thickness of about 0.01 to 0.2 μm.

  In addition, flexographic printing is flexible in the relief printing plate part, and it is printing at a very low printing pressure called kiss touch, so a transparent electrode whose characteristics are destroyed by applying a high pressure, etc. It is also suitable for printing on a substrate on which is formed. For this reason, it is a printing method especially suitable for formation of the light emitting layer of an organic EL element.

In an ink supply device of a printing press that prints the light emitting layer of an organic EL element, in order to prevent ink drying on the surface of the anilox roll, the lower peripheral surface of the anilox roll is rotated while immersed in the ink reservoir of the ink chamber, and the anilox roll is always The surface needs to be wet.
A system is used in which excess ink on the surface of the anilox roll is scraped off by a doctor and ink is applied onto the flexographic plate (on the relief plate). The types of doctors include blades and rolls, which are appropriately selected and used from the viewpoint of doctoring properties and foreign matters generated during doctoring.

JP 2001-185352 A JP 2005-59348 A

Although the blade-shaped doctor is excellent in doctoring properties, the doctor's blade tip is scraped and brought into the ink as foreign matter because the doctor's blade tip is brought into contact with the anilox roll under pressure. For this reason, it is not suitable for the manufacturing process of thin film semiconductors, such as an organic EL device.
On the other hand, when a roll-shaped doctor is used, it is advantageous with respect to the generation of foreign matter, but when the nip with the anilox roll is applied, the load is concentrated on the end of the peripheral surface of the doctor roll, so that the doctor roll itself is bent. For this reason, the nip pressure at the center of the doctor roll peripheral surface is weakened, and the balance of the nip pressure in the entire area of the doctor roll peripheral surface is deteriorated.

On the other hand, it is possible to weaken the pushing of the doctor roll and suppress the bending of the doctor roll. However, in a state where the nip pressure of the doctor roll is weak, a doctoring defect occurs when the viscosity of the ink is high.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a doctor roll that suppresses the generation of foreign matters in the doctoring process and has high doctoring performance, and a relief printing press using the doctor roll. Another object of the present invention is to provide an organic EL panel manufacturing apparatus capable of producing a high-quality polymer organic EL panel at low cost.

  In order to achieve the above object, a first aspect of the present invention includes: a platen on which a substrate to be printed is placed; a rotary plate cylinder on which a relief plate is installed and disposed on the platen; and the plate cylinder An anilox roll arranged so as to face, an ink chamber for accommodating a part of the anilox roll and supplying ink to the anilox roll, a doctor roll provided for scraping the ink supplied on the anilox roll; In the letterpress printer provided with the above, the doctor roll of the letterpress printer is characterized in that the hardness of the peripheral surface portion at both ends is lower than the hardness of the peripheral surface portion at the center portion.

2nd aspect of this invention is good also considering each width | variety of the axial direction of the both ends of the said doctor roll as 10 to 20% of the full length of the axial direction of the said doctor roll.
In the third aspect of the present invention, the hardness difference between the hardness of the peripheral surface portion at the both end portions and the hardness of the peripheral surface portion at the central portion may be 10 ° or more and 30 ° or less.
4th aspect of this invention is good also considering the axial full length of the said doctor roll as 110% or more and 120% or less with respect to the full length of the axial direction of the said anilox roll.

According to a fifth aspect of the present invention, the doctor roll according to any one of the first to fourth aspects is provided, and the ink is a polymer organic EL material for printing an organic light emitting tank on the substrate to be printed. The letterpress printing machine is characterized by being dissolved in a solvent.
According to a sixth aspect of the present invention, in the relief printing press according to the fifth aspect, a distance adjusting mechanism that allows the distance between the anilox roll and the plate cylinder to be adjusted in size can be provided.
According to a seventh aspect of the present invention, there is provided an organic EL panel manufacturing apparatus for manufacturing an organic EL panel using the relief printing press according to the fifth or sixth aspect.

In the doctor roll of the present invention, the end surface region of the doctor roll has a relatively strong nip pressure to the anilox roll, but the end of the peripheral surface can be reduced by making the hardness of this region lower than the hardness of the center region of the doctor roll. The nip pressure to the anilox roll in the partial area can be reduced.
In addition, by suppressing the reduction of the nip pressure in the central area of the doctor roll peripheral surface by making the hardness of the central area of the doctor roll peripheral surface relatively weak in the doctor roll higher than the hardness of the doctor roll peripheral surface end area. Can do.
According to this organic EL panel manufacturing printing machine using a doctor roll, it is possible to produce an organic EL panel on which a polymer organic light-emitting layer is printed and a high-quality polymer with little film thickness unevenness due to doctoring unevenness. An organic EL panel can be produced at low cost.

It is the schematic which shows the structure of the organic EL (flexo) printing machine in this invention. It is the upper surface schematic of the anilox roll and doctor roll in this invention. It is a printing evaluation and the evaluation result of the display state of an organic electroluminescent panel.

Hereinafter, an embodiment of the present invention will be described focusing on an ink supply mechanism 109 provided with an anilox roll 101 in the resin relief printing press shown in FIG. The doctor roll, the relief printing press, and the organic EL panel manufacturing apparatus according to the present invention are not limited to the embodiments described below.
The resin relief printing press shown in FIG. 1 is a cylinder-type printing copper 105 on which a relief forming plate 104 for pattern formation is mounted, an anilox roll 101 for supplying ink in contact with the relief plate 104, and ink for supplying ink to the anilox roll 101. A chamber 108, a doctor roll 102 that scrapes off excess ink on the anilox roll 101, a rotary plate cylinder 105 on which a relief plate 104 for pattern formation is mounted via an under-cushion cushion 103, and a printing substrate 107 are placed. This is a printing apparatus composed of a substrate surface plate 106.

  The anilox roll 101 that can be used for the resin relief printing of the present invention is a ceramic in which a chromium oxide film formed by plasma spraying chromium oxide on a core roll made of SUS material or the like is patterned 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, and the obtained pattern is subjected to chrome plating.

As the pattern formed on the aniloc roll 101, any pattern such as a helical pattern, FM pattern, honeycomb pattern, diamond pattern, or ART pattern can be used.
These patterns may be appropriately angled to prevent moire on the printed material. After these patterns are formed, the anilox roll 101 surface is preferably polished to prevent the doctor roll 102 from being damaged. Specifically, it is desirable to polish so that protrusions of 4 μm or more are eliminated from the pattern bank portion of the anilox roll 101.

As a mechanism for rotating the anilox roll 101, it is desirable to perform direct drive with a servo motor capable of controlling rotation with high accuracy because uneven rotation speed greatly affects 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 A rubber roll may be produced by wrapping a rubber material such as rubber, or a material obtained by wrapping a PFA heat shrinkable tube on these rubber rolls may be used. These rubber materials are selected from the resistance to the solvent used as the ink.

The surface of these rubber rolls preferably has 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 dusting and smooth liquid scraping surface can be obtained. I can do it.
In printing on a general flexographic printing machine, doctoring by the doctor roll 102 causes a difference in the nip pressure to the anilox roll 101 between the peripheral surface end region 203 and the peripheral surface central region 204 of the doctor roll 102, and uneven doctoring. Is likely to occur.

  Therefore, the entire peripheral surface of the doctor roll 102 is divided into two peripheral surface end regions 203 and 203 having the axial width of both ends 10 to 20% of the total axial length 202 of the doctor roll, and the other 60. It is divided into the peripheral surface central region 204 occupying -80%, and the hardness difference between the hardness of the peripheral surface end region 203 and the hardness of the peripheral surface central region 204 is set to 10 ° or more and 30 ° or less. By making the hardness of the peripheral surface end regions 203 and 203 lower than the hardness of the peripheral surface central region 204, the balance of the nip pressure in the entire peripheral surface of the doctor roll 102 can be improved. However, the hardness of the entire peripheral surface of the doctor roll 102 is preferably within a range of 30 to 70 ° in terms of JIS-A hardness.

When the axial widths of the two peripheral surface end regions 203 and 203 of the doctor roll 102 are each less than 10% of the total axial length 202 of the doctor roll 102, when niping with the anilox roll 101, The load at the end of the doctor roll 102 cannot be released and the deflection of the doctor roll 102 itself occurs.
On the contrary, when the axial widths of the two peripheral surface end regions 203 and 203 are longer than 20% of the total axial length 202 of the doctor roll 102, the center of the peripheral surface of the doctor roll 102 that is originally intended to increase the nip pressure. Since the nip pressure in the region 204 is weaker than the nip pressure when the width is 10 to 20% of the total length 202 in the axial direction of the doctor roll 102, the balance of the nip pressure in the entire peripheral surface of the doctor roll 102 is improved. Absent.

  Further, the two peripheral surface end regions 203 and 203 of the doctor roll 102 having relatively low hardness are respectively 10% to 20% of the total length 202 in the axial direction of the doctor roll 102, and other relatively high hardnesses. If the peripheral surface central region 204 is 60 to 80% of the total length 202 in the axial direction of the doctor roll 102, the strong and weak portions of the nip pressure on the doctor roll 102 are offset and the nip pressure is applied to the entire peripheral surface of the doctor roll 102. The balance is improved. The total length 202 in the axial direction of the doctor roll 102 is preferably 110 to 120% of the total length 201 in the axial direction of the anilox roll 101.

Regarding the processing of the doctor roll 102 of the present invention, rubber is wound around the core of the doctor roll 102 and processed into a columnar shape, and the hardness of the peripheral surface center region 204 and the peripheral surface end regions 203 and 203 of the doctor roll 102 are different from each other. Then, the rubber is processed so as to have the same thickness, and a PFA heat shrink tube is wound around the entire rubber roll.
As the mechanism for rotating the doctor roll 102, since the rotational speed unevenness has a great influence on the printed matter, it is desirable to use a servo motor capable of controlling the rotation with high accuracy and perform direct drive. It is desirable to have a system that can be controlled in a synchronously rotatable manner.

  The actual operation when using this printing machine will be described. After placing the glass print substrate 107 on the substrate surface plate 106, a printing operation is started by a print start instruction. During this time, ink is supplied from the ink chamber 108 on 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 from the anilox roll 101 onto the relief plate 104, and then the glass cover placed on the substrate surface plate 106 is synchronized with the rotation of the plate cylinder 105. Printing is performed on the printed circuit board 107.
The speed at which the ink is transferred from the anilox roll 101 onto the relief plate 104 may be the same as the doctoring speed. However, if the doctoring speed is relatively low, the transfer takes time. Also good.

In printing by the printing press, when the portion exposed from the ink chamber 108 on the surface of the anilox roll 101 is dried, the ink on the surface is dried and solidified. In order to prevent this, it is desirable that the anilox roll 101 is rotated even when the ink is not transferred onto the relief plate 104 to keep the surface wet. Therefore, by providing a distance adjusting mechanism that can adjust the distance between the anilox roll 101 and the plate cylinder 105, when the ink is not transferred onto the relief plate 104, the distance between the anilox roll 101 and the plate cylinder 105 is set to You may comprise so that it may become larger than the time of transcription | transfer.
By performing the above operation, it is possible to obtain a printed matter with a higher quality than the conventional printed matter.

Example 1
Next, examples of the present invention will be described.
Here, trial manufacture and measurement were performed for the following Example 1 and Comparative Examples 1 and 2.
First, an ITO (indium-tin oxide) thin film is formed on a 300 mm square glass substrate by sputtering, and the ITO film is patterned by photolithography and etching with an acid solution. Pixel electrodes were formed so that two displays could be taken. The line pattern of the pixel electrode per display surface was a pattern in which 1950 lines were formed with a line width of 40 μm and a space of 20 μm.

Next, an insulating layer was formed as follows.
First, a polyimide resist material was spin-coated on the entire surface of a glass substrate on which pixel electrodes were formed. The spin coating condition was rotated at 150 rpm for 5 seconds, and then rotated at 500 rpm for 20 seconds to make a single coating, and the height of the insulating layer was 1.5 μm. An insulating layer having a line pattern between pixel electrodes was formed by photolithography on the photoresist material applied to the entire surface.

Next, a PEDOT solution Vitron CH-8000 was prepared as a hole transport ink, and an ink having a solid content concentration of 1.5%, a viscosity of 15 mPa · S, and a vapor pressure of 1.1 kPa was prepared. A hole transport layer was formed on the entire surface of the substrate.
Thereafter, unnecessary portions outside the pixel region were wiped with a waste cloth and dried in the atmosphere at 200 ° C. for 30 minutes to form a hole transport layer. The film thickness at this time was 50 nm.

Next, organic light-emitting ink in which polyphenylene vinylene derivative, an organic light-emitting material, is dissolved in toluene to a concentration of 2% is used, and organic light emission is performed in line with the line pattern directly above the pixel electrode sandwiched between insulating layers. The layer was printed by letterpress printing.
The doctor roll 102 used at this time has an axial width of the two peripheral surface end regions 203 and 203 with relatively low hardness of 15% of the total length 202 in the axial direction of the doctor roll 102, respectively. The axial width of the surface center region 204 was set to 70% of the total axial length 202 of the doctor roll 102. Further, the hardness difference between the hardness of the peripheral surface end region 203 of the doctor roll 102 and the hardness of the peripheral surface central region 204 was set to 20 °.

Further, the printing plate was washed using a washing device (not shown) using an anilox roll 101 of 750 lines / inch and a water developing type photosensitive resin plate.
As a result, the film thickness of the organic light emitting layer after printing and drying was 80 nm.
A cathode layer made of Ca and Al was formed thereon by mask vapor deposition using a resistance heating vapor deposition method in a line pattern orthogonal to the pixel electrode line pattern. Finally, in order to protect these organic EL constituents from external oxygen and moisture, they were hermetically sealed using a glass cap and an adhesive to produce an organic EL panel.

In the periphery of the display portion of the organic EL panel obtained in this way, there are an extraction electrode on the anode side connected to each pixel electrode and an extraction electrode on the cathode side, which are obtained by connecting them to a power source. The lighting display of the organic EL panel was confirmed, and the light emission state was checked.
In addition, before printing an organic light emitting layer on a panel, it printed on 300 * 300 mm soda glass, and the printing nonuniformity was confirmed.

(Comparative Example 1)
The doctor roll 102 used has an axial width of the two peripheral surface end regions 203 and 203 of relatively low hardness, 5% of the total axial length 202 of the doctor roll 102, respectively, and a relatively high hardness center of the peripheral surface. Example 2 was the same as Example 1 except that the area 204 was a printing machine in which the axial width of the region 204 was 90% of the total length 202 of the doctor roll 102.

(Comparative Example 2)
The doctor roll 102 used has an axial width of two peripheral surface end regions 203 and 203 of relatively low hardness, 25% of the total axial length 202 of the doctor roll 102, respectively, and a relatively high hardness peripheral surface center. The same operation as in Example 1 was performed except that the area 204 had a printing machine in which the axial width of the region 204 was 50% of the total axial length 202 of the doctor roll 102.

  The evaluation results of the appearance of the organic light emitting layer formed on the soda glass in Example 1 and Comparative Examples 1 and 2 as described above, the panel thickness variation of the produced organic EL panel, and the evaluation results of the panel light emission state are shown in FIG. 3 shows. As shown in the drawing, it can be seen that better results can be obtained by improving the doctoring performance in the embodiment of the present invention than in the comparative example.

DESCRIPTION OF SYMBOLS 101 ... Anilox roll 102 ... Doctor roll 103 ... Under-cushion cushion 104 ... Letterpress plate 105 ... Plate cylinder 106 ... Substrate surface plate 107 ... Printed substrate 108 ... Ink chamber 109 ... Ink supply mechanism 201 ... Total length 202 in the axial direction of the anilox roll ... Total length 203 in the axial direction of the doctor roll ... End region of the doctor roll peripheral surface 204 ... Central region of the doctor roll peripheral surface

Claims (7)

A surface plate on which a substrate to be printed is placed, a rotary plate cylinder on which a relief plate is installed and disposed on the surface plate, an anilox roll disposed so as to face the plate cylinder, and a part of the anilox roll In a letterpress printing machine comprising an ink chamber for containing ink and supplying ink to the anilox roll, and a doctor roll provided for scraping off the ink supplied on the anilox roll,
A doctor roll for a letterpress printing machine, characterized in that the hardness of the peripheral surface portion at both ends is lower than the hardness of the peripheral surface portion at the central portion.   The doctor roll for a letterpress printing machine according to claim 1, wherein each axial width of both ends of the doctor roll is 10% to 20% of the total axial length of the doctor roll.   The relief printing press according to claim 1 or 2, wherein a hardness difference between a hardness of the peripheral surface portion at the both end portions and a hardness of the peripheral surface portion at the central portion is set to 10 ° to 30 °. Doctor roll.   The letterpress printing press according to any one of claims 1 to 3, wherein an axial total length of the doctor roll is 110% or more and 120% or less with respect to an axial total length of the anilox roll. Doctor roll. While providing the doctor roll as described in any one of Claims 1-4,
The letterpress printing machine, wherein the ink is formed by dissolving a polymer organic EL material in a solvent in order to print an organic light emitting tank on the substrate to be printed.   6. The letterpress printing machine according to claim 5, further comprising a distance adjusting mechanism that can adjust the distance between the anilox roll and the plate cylinder.   An organic EL panel manufacturing apparatus for manufacturing an organic EL panel using the relief printing press according to claim 5 or 6.

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