JP2006248065A - Ink supply base material for letterpress printing, and apparatus and method for printing using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for ink supply which enable a sufficient ink supply to a letterpress plate even when ink is of low viscosity and further which enable the adjustment of the thickness of a printed film. <P>SOLUTION: A base material being flexible and having closed cells is sliced so that the cells in the surface of the base material are cut. The ink is held in the base material having an indented shape thus obtained and it is received by projections of the letterpress plate. The ink supply to the letterpress plate is performed in this way. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink supply base material that supplies a low-viscosity ink such as an organic light emitter to a relief printing plate, and a printing method and printing apparatus using the same.

  Research and development of lightweight, high-efficiency flat panel displays for computer information display or television screen display is underway. A cathode ray tube (CRT) that has been widely used as a display that has been mainly used in the past is a cathode ray tube (CRT) that has excellent luminance and color reproducibility. As panel displays, liquid crystal panel displays or plasma panel displays have been commercialized, and some products are being replaced. However, the liquid crystal panel display has a problem that the viewing angle is narrow and the responsiveness to high-speed pixel signals is not sufficient, and the plasma panel display consumes a large amount of power. There is a problem.

Recently, an organic electroluminescence element using an organic light emitting material (hereinafter referred to as an organic EL element) has been attracting attention. Even if the organic compound is used as a light emitting material, it is self-luminous. It is expected to realize a flat panel display with low power consumption and high response speed and no viewing angle dependency.
FIG. 5 shows an example of the structure of this type of organic EL element. The organic EL element 100 of this example is a transparent pixel electrode (anode) made of ITO (indium tin oxide) on a transparent glass substrate 101. 102, a hole transport layer 103, a light emitting layer 104, an electron transport layer 105, and a metal cathode 106 are sequentially formed by, for example, a vacuum deposition method.

In the organic EL element 100 having this configuration, when a DC voltage is applied between the anode pixel electrode 102 and the cathode 106 from the DC power source 107, holes (holes) as carriers injected from the pixel electrode 102 are transported by holes. Each of them moves through the layer 103, and in the light emitting layer 104, recombination of these electron-hole pairs occurs, and light emission 108 having a predetermined wavelength is generated therefrom, which can be observed from the outside of the transparent glass substrate 101. .
Further, as another example of the specific layer structure of the organic EL element 100 described above, as shown in FIG. 6, the material of the hole transport layer 103 is poly (3,4) -ethylenedioxythiophene (hereinafter abbreviated as PEDOT). ), And the electron of poly (2-methoxy-5- (2′-ethylhexyloxy) -1,4-phenylenevinylene) (hereinafter abbreviated as MEH-PPV) as a layer that doubles as an electron transport layer and a light-emitting layer A structure is also known in which a transporting light emitting layer 110 is used, and a cathode 106 made of an aluminum electrode layer and a calcium (Ca) layer 111 that enhances electron injectability is provided on the upper layer.

  Next, FIG. 2 shows one configuration example in which the organic EL element having the basic structure shown in FIG. 1A or 1B is applied to a flat display device. As shown in the drawing, an organic laminated structure composed of an electron transport layer 115 and a hole transport layer 116 is disposed between the cathode 117 and the anode 118 in a predetermined pattern. The cathode 117 and the anode 118 are provided in stripes crossing each other, and are selected by the luminance signal circuit 120 and the control circuit 121 with a built-in shift register, respectively, and applied with a signal voltage. Thus, the EL element portions existing at the positions (pixels) where the selected cathode 117 and anode 118 intersect each other are configured to emit light individually.

  Various methods for forming an organic light-emitting material by printing have been studied as a method for forming the light-emitting layer of the organic EL element, and one of them is a relief printing method. Patent Documents 1 to 3 describe production of an organic EL display using a relief printing method.

In the relief printing method, a method using an anilox roll as an ink supply base material for supplying ink to the relief plate is known. According to this method, a fine concave portion is formed on a roll such as a metal cylinder, and ink is replenished and held in the concave portion, and printing is performed by supplying the ink held in the concave portion to the convex portion of the relief printing plate. However, organic phosphors generally have low solubility in the target solvent and a low solids ratio because a sufficient solid content ratio cannot be obtained for the target printing method. In order to achieve this, it is difficult to combine an ordinary anilox roll with a letterpress. For this reason, when an organic EL element is produced using a metal hard anilox roll, an organic luminescent material ink having a low viscosity is not easily received by the relief printing plate, and there is a problem that the ink cannot be efficiently supplied to the relief printing plate. Further, the metallic anilox roll has a problem that a lot of cost is required for processing a fine recess.
Japanese Patent Laid-Open No. 10-77467 JP 2001-155858 A JP 2004-322329 A

  The present invention has been made in order to solve the above problems, and the problem is that in letterpress printing, an ink supply substrate for supplying low-viscosity ink to the convex portions of the letterpress, and a printing method, The object is to provide a printing device.

  By the way, according to the study of the present inventor, in the relief printing method, the ink supply base material that supplies ink to the relief of the relief plate has a recessed portion that is sliced so as to cut closed cells, and has an appropriate hardness. It has been found that the use of a sponge-like material having an ink allows the ink to be efficiently received from the ink supply base material to the relief plate. In addition, when a sponge-like substrate having an open cell shape is used as the ink supply substrate, the amount of ink retained in the bubbles is not constant, and thus the thickness of the printed ink cannot be arbitrarily adjusted. However, when an ink supply substrate having a closed cell shape is used as the ink supply substrate, the amount of ink retained in the recess can be adjusted by the bubble diameter of the closed cell, and thus such a film thickness Did not cause any problems.

The present invention was made based on such knowledge, and the invention according to claim 1 is an ink supply substrate for supplying ink to a relief printing plate used in a relief printing method.
The hardness of the ink supply substrate is 5 to 80 degrees according to JIS A standard,
An ink supply base material for letterpress printing, wherein the surface of the ink supply base material has a concave portion that is sliced so as to cut closed cells.

According to a second aspect of the present invention, there is provided the ink supply substrate for letterpress printing according to the first aspect, wherein the closed-cell-shaped concave portion has an average diameter of 0.1 μm to 1000 μm.

The invention described in claim 3 is the ink supply for letterpress printing according to claim 1 or 2, wherein the porosity per unit volume of the ink supply substrate is 25% to 99%. Base material.

The invention according to claim 4 uses at least one of a fluorine-based elastomer and a fluorine-based resin, and the ink supply substrate for relief printing according to any one of claims 1 to 3.

The invention according to claim 5 is at least an ink replenishing device;
An ink supply device that is replenished with ink from the ink replenishing device;
A relief printing plate supplied with ink from the ink supply device;
An ink removing device for removing excess ink from the ink supply device;
A printing apparatus comprising: a relief printing ink supply substrate according to any one of claims 1 to 4, wherein the ink supply apparatus is a relief printing apparatus.

In a printing method using a letterpress,
Ink is supplied to a substrate having a concave portion with a sliced shape so that the surface cuts closed cells,
After holding the ink in the recesses on the surface of the substrate,
A printing method comprising printing the ink by receiving the ink on a convex portion of a relief printing plate.

  Since the ink supply base material according to the present invention uses a flexible sponge-like base material, the portion of the ink supply base material that adheres to the relief plate is flexibly deformed according to the convex portion, Adhesion with the part increases. For this reason, even if low viscosity ink was used, a sufficient amount of ink could be supplied to the relief printing plate. In addition, by changing the bubble diameter of the closed cell, the ink holding amount of the ink supply base material can be manipulated and the ink supply amount to the convex part of the relief printing plate can be changed. Therefore, the film thickness can be easily manipulated.

  In addition, the sponge used in the present invention only needs to have a concave portion formed by slicing so as to cut bubbles on the surface, and does not require high-definition processing, so compared to a normal anilox roll We were able to keep costs for replacement low.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 3A is a cross-sectional view of a relief printing ink supply substrate according to the present invention.
FIG. 3B is a schematic diagram of the printing apparatus and printing method according to the present invention.

First, as shown in FIG. 3 (a), the surface bubble portion of the sponge 20 having closed cells is sliced so as to be cut to form a recess 21b, which is used as a relief printing ink supply base material (hereinafter simply referred to as “platelet ink supply substrate”) Ink supply base material). The sponge 20 holds the ink containing an organic solvent in the concave portion, and the ink is supplied by transferring the ink to the convex portion of the relief printing plate. Since the sponge is a closed cell, ink is not held in the bubble 21a inside the sponge.

  The pore diameter of the closed cells of the ink supply substrate according to the present invention is preferably 0.1 μm to 1000 μm. If the pore diameter is less than 0.1 μm, it is not possible to supply a sufficient amount of ink for printing to the convex portion of the relief plate, and if it exceeds 1000 μm, the uniformity of the concave portion formed by the bubbles is impaired, leading to the convex portion of the relief plate It becomes impossible to supply a uniform ink.

  The porosity per unit volume of closed cells of the ink supply substrate according to the present invention is preferably 25% to 99%. If the porosity is less than 25%, the probability of forming concave portions due to bubbles on the surface of the sponge when slicing is reduced, so that uniform ink supply to the convex portions of the relief printing is not performed. The stability of the is impaired.

  The material of the ink supply base material according to the present invention preferably has flexibility and solvent resistance to the organic solvent used in the ink. Specifically, nitrile rubber, silicone rubber, isoprene rubber, styrene butadiene rubber, butadiene In addition to rubber such as rubber, chloroprene rubber, butyl rubber, acrylonitrile rubber, ethylene propylene rubber, urethane rubber, polyethylene, polystyrene, polybutadiene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyamide, polyethersulfone, polyethylene terephthalate, One or more types can be selected from synthetic resins such as polyethylene naphthalate, polyethersulfone, and polyvinyl alcohol, copolymers thereof, and natural polymers such as cellulose. Ethylene, polyvinylidene fluoride, it is preferable to use a fluorine-based resin such as polyethylene hexafluoride vinylidene and copolymers thereof.

The hardness of the closed-cell sponge 20 is preferably 5 to 80 degrees according to JIS A standards. When the hardness is less than 5 degrees, the stability of the sponge itself is poor, and when it exceeds 80 degrees, the flexibility is impaired, and it becomes difficult to supply ink to the convex portions of the relief printing plate.

  Next, an example of the printing apparatus and printing method of the present invention will be described. First, as shown in FIG. 3B, a roller-shaped ink supply device 27 is prepared. On the surface of the ink supply device 27, a closed-cell sponge 20 is formed as an ink supply substrate. The ink 22 is replenished from an ink replenishing device 23 installed at the top of the ink supply device 27. At this time, excess ink 22 replenished to the ink supply device 27 is removed by the ink removing device (doctor roll 24). A doctor blade can be used in place of the doctor roll, but since the surface of the ink supply device 27 is a relatively soft sponge material, it is preferable to use a doctor roll from the viewpoint of preventing foreign matter from entering the printed matter. In addition to the fountain roll and the ink chamber, a coater such as a slit coater, a die coater, or a cap coater, or a combination thereof can be used for the ink replenishing device 23.

  After excess ink is removed by the doctor roll 24, ink is supplied to the convex portions of the relief plate provided on the cylinder 25. The ink supplied to the convex portions of the relief printing is printed onto the transfer medium 26. Although not shown, a relief plate may be provided on a flat plate, and a roller-shaped ink supply device may be rotated on the plate to supply ink.

The present invention is suitable for high-definition pattern printing, and particularly suitable for manufacturing electronic members. For example, FIG. 4 shows an organic EL element obtained by the present invention. The organic light emitting device 10 includes a translucent substrate 11, a transparent conductive layer 12, a hole injection layer 13, an organic light emitting layer 14, and a cathode layer 15, and the organic light emitting layer 14 can be formed according to the present invention.

  In the organic light emitting device 10, a glass substrate or a plastic film or sheet can be used as the translucent substrate 11. If a plastic film is used, an organic light emitting device can be manufactured by winding, and the device can be provided at low cost. As the plastic, for example, polyethylene terephthalate, polypropylene, cycloolefin polymer, polyamide, polyethersulfone, polymethyl methacrylate, polycarbonate and the like can be used. Moreover, you may laminate | stack other gas barrier films, such as a ceramic vapor deposition film, a polyvinylidene chloride, a polyvinyl chloride, an ethylene-vinyl acetate copolymer saponified material, on the side which does not form the transparent conductive layer 12 into a film.

Examples of the material forming the transparent conductive layer 12 include a complex oxide of indium and tin (hereinafter referred to as ITO). In addition, a semi-transparent metal such as aluminum, gold, or silver, or an organic semiconductor such as polyaniline may be used.
Examples of the material forming the hole injection layer 13 include conductive polymer materials such as polyaniline derivatives, polythiophene derivatives, polyvinylcarbazole derivatives, and mixtures of poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid.

  The organic light emitting layer 14 is a layer containing an organic light emitter, and emits light when a voltage is applied. Examples of organic light-emitting materials include coumarin-based, perylene-based, pyran-based, anthrone-based, porphyrin-based, quinacridone-based, N, N′-dialkyl-substituted quinacridone-based, naphthalimide-based, N, N′-diaryl-substituted pyrrolopyrrole-based materials. Organic light-emitting materials soluble in organic solvents such as iridium complexes, organic light-emitting materials dispersed in polymers such as polystyrene, polymethyl methacrylate, polyvinyl carbazole, polyarylenes, polyarylene vinylenes, Examples thereof include polymer organic light emitting materials such as polyfluorene-based materials.

  As the material for the cathode layer 15, materials corresponding to the light emission characteristics of the organic light emitting medium layer can be used. For example, simple metals such as lithium, magnesium, calcium, ytterbium and aluminum, and stable metals such as gold and silver can be used. And alloys thereof. Alternatively, a conductive oxide such as indium, zinc, or tin can be used.

In order to manufacture the organic light-emitting element described above using the present invention, the object to be transferred 26 is obtained by laminating the transparent conductive layer 12 and the hole injection layer 13 on the translucent substrate 11, and the organic light emitting as the ink 22. Use ink containing material.

The ink containing the organic light emitting material is supplied to the convex portion of the relief printing as described above, and is printed on the transfer substrate 26 described above. Solvents used in inks that dissolve or disperse luminescent materials include, for example, toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyltone, cyclohexanone, methanol, ethanol, isopropyl alcohol, ethyl acetate, butyl acetate, chloroform, chloride. Examples thereof include methylene, dichloroethane, trichloroethane, tetrachloroethylene, water alone or a mixed solvent thereof. In particular, aromatic solvents and halogen solvents are excellent for dissolving organic light emitting materials.
Moreover, surfactant, antioxidant, a viscosity modifier, a ultraviolet absorber, a desiccant, etc. may be added to the ink containing an organic luminescent material as needed.

Examples of the present invention and comparative examples are shown below.

<Example 1>
In the ink supply apparatus in the above embodiment, the closed cell sponge 20 is used as the ink supply base material. The closed cell fluorine elastomer (thickness: 1.0 mm, pore diameter: 100 to 150 μm, porosity: approx. 60%) was used. This closed-cell fluorine-based elastomer was fixed with an adhesive tape to a flexographic printing proofing machine (manufactured by Matsuo Sangyo Co., Ltd.) equipped with a striped resin relief plate having a convex part of 120 μm and a concave part of 380 μm. A substrate obtained by laminating a mixture of ITO, poly (3,4-ethylenedioxythiophene) and polystyrene sulfonic acid on glass using a toluene solution of polyarylene vinylene 1.0% by weight as an ink containing an organic light emitting material A transcription test was conducted. The transfer film was taken into a personal computer as an image and the area ratio was calculated. As a result, the area ratio showed a transfer ratio of 95%, and the line shape could be produced with a width accuracy of ± 5 μm. The transfer film thickness was 110 nm and the film thickness accuracy was ± 5 nm.

<Comparative Example 1>
In the same embodiment as in Example 1 above, flexo printing manufactured by Matsuo Sangyo Co., Ltd. equipped with a striped resin relief plate having a convex portion of 120 μm and a concave portion of 380 μm using an anilox roll of 150 lines and 45 μm without using the closed-cell sponge 20 The anilox roll was equipped on the proofreading machine. A substrate obtained by laminating a mixture of ITO, poly (3,4-ethylenedioxythiophene) and polystyrene sulfonic acid on glass using a toluene solution of polyarylene vinylene 1.0% by weight as an ink containing an organic light emitting material A transcription test was conducted. When the transfer film was taken into a personal computer as an image and the area ratio was calculated, the transfer ratio was 5% or less, which was caused by poor ink supply to the convex portions of the relief plate due to poor adhesion between the anilox roll and the relief plate. there were.

<Comparative example 2>
In the same embodiment as Example 1 above, Matsuo Sangyo Co., Ltd. equipped with a striped resin relief plate having a convex portion of 120 μm and a concave portion of 380 μm using a known polyurethane open-cell sponge without using the closed-cell sponge 20. The flexographic printing proofing machine was equipped with an open-cell sponge. A substrate obtained by laminating a mixture of ITO, poly (3,4-ethylenedioxythiophene) and polystyrene sulfonic acid on glass using a toluene solution of polyarylene vinylene 1.0% by weight as an ink containing an organic light emitting material A transcription test was conducted. When the transfer film was taken into a personal computer as an image and the area ratio was calculated, the transfer ratio was 95%. The average film thickness was 250 nm. A transfer test was performed by changing the roughness of the open-cell sponge, but no difference in film thickness was observed.

(A) FIG. 1A is a cross-sectional view showing one structural example of an organic EL element. (B) FIG.1 (b) is sectional drawing which shows the other structural example of an organic EL element. FIG. 2 is a structural diagram showing an example of a display device using an organic EL element. (A) FIG. 3A is a cross-sectional view of the relief printing ink supply substrate of the present invention. (B) FIG. 3B is a schematic view of the printing apparatus and printing method of the present invention. It is sectional drawing which shows one structural example of an organic EL element.

Explanation of symbols

100 Organic Light Emitting Element 101 Glass Substrate 102 Pixel Electrode (Anode)
103 hole transport layer 104 light emitting layer 105 electron transport layer 106 cathode 107 direct current power supply 108 light emission 110 electron transport light emitting layer 111 calcium (Ca) layer 115 electron transport layer 116 hole transport layer 117 cathode 118 anode 120 luminance signal circuit 121 built-in shift register Control circuit 20 closed cell sponge 21a bubble 21b inside the sponge recessed portion 22 obtained by slicing the closed cell 22 ink 23 ink replenishing device 24 doctor roll 25 cylinder body with letterpress 26 transferred material 27 ink supply device 10 organic light emitting element 11 Translucent substrate 12 Transparent conductive layer 13 Hole injection layer 14 Organic light emitting layer 15 Cathode layer

Claims (6)

In the ink supply base material that supplies ink to the relief printing plate used in the relief printing method,
The hardness of the ink supply substrate is 5 to 80 degrees according to JIS A standard,
An ink supply base material for letterpress printing, wherein the surface of the ink supply base material has a concave portion that is sliced so as to cut closed cells. 2. The ink supply substrate for letterpress printing according to claim 1, wherein the average diameter of the closed-cell-shaped recesses is 0.1 [mu] m to 1000 [mu] m. The ink supply substrate for letterpress printing according to claim 1 or 2, wherein the porosity of the ink supply substrate per unit volume is 25% to 99%. The ink supply substrate for letterpress printing according to any one of claims 1 to 3, wherein at least one of a fluorine-based elastomer and a fluorine-based resin is used. At least an ink refilling device,
An ink supply device that is replenished with ink from the ink replenishing device;
A relief printing plate supplied with ink from the ink supply device;
An ink removing device for removing excess ink from the ink supply device;
A printing apparatus comprising: a relief printing ink supply substrate according to any one of claims 1 to 4, wherein the ink supply apparatus is a relief printing apparatus. In a printing method using a letterpress,
After the surface is supplied with ink to a base material having a concave portion sliced so as to cut closed cells, the ink is retained in the concave portion of the base material,
A printing method comprising printing the ink by receiving the ink on a convex portion of a relief printing plate.

Images