JP5899752B2 - Letterpress printing apparatus and organic EL panel manufacturing method - Google Patents

Description

  The present invention relates to a printing apparatus for producing a polymer organic EL display panel and a method for producing a polymer organic EL display panel.

  An organic electroluminescence (hereinafter EL) element is a light-emitting element having a structure in which an organic light-emitting layer made of an organic light-emitting material is formed between an anode and a cathode that face each other. In order to obtain efficient light emission, the film thickness of the organic light emitting layer is an important factor for obtaining efficient light emission. Therefore, it is necessary to control the film thickness at about several tens of nm. Further, in order to make this a display, it is necessary to pattern it with high definition.

  The organic light emitting material used for the organic light emitting layer is classified into a low molecular material and a polymer material, and the method of forming the organic light emitting layer differs depending on the type of the organic light emitting material.

  In general, a low molecular weight material forms a thin film on a substrate by resistance heating vapor deposition (vacuum vapor deposition) or the like. When full-coloring the organic EL element, a method is employed in which a luminescent material having a different emission color is deposited on each pixel using a mask having a pattern corresponding to the pixel shape of each color. Although this method is an excellent method for uniformly forming a thin film shape, there is a problem in that the mask pattern accuracy is difficult to be obtained when the deposited substrate becomes large.

  On the other hand, in the case of polymer materials, a method in which an organic light emitting material is dissolved or dispersed in a solvent to form an ink and a thin film is formed by a wet coating method is mainly used. As the wet coating method, there are a spin coating method, a bar coating method, a protruding coating method, a dip coating method, etc., but it is difficult to use these methods for high-definition patterning and color separation for full color. . Therefore, it is considered that pattern printing by an ink jet method or a printing method is effective as a means for patterning the organic light emitting material layer for full color.

  As one of high-definition patterning methods, for example, there is an ink jet method in which an organic light emitting material dissolved in a solvent is jetted onto a substrate from an ink jet nozzle and dried on the substrate (Patent Document 1). In this method, since the ink droplets ejected from the nozzle are spherical, the ink spreads in a circular shape when landing on the substrate, and the formed pattern shape is not linear or has landed. There is a problem that the linearity of the pattern cannot be obtained due to poor accuracy.

  On the other hand, letterpress printing, reversal printing, screen printing, and the like have been proposed as pattern forming methods by printing. In organic EL elements and displays, a glass substrate is often used as a base material, and a method using a hard printing plate made of metal such as a gravure printing method is not suitable. Therefore, a printing method using a rubber printing plate having elasticity, an offset printing method using a rubber printing blanket, a relief printing plate using a photosensitive resin plate mainly composed of elastic rubber or other resin. The printing method is considered an appropriate printing method. Actually, as a trial of these printing methods, a pattern printing method by offset printing (Patent Document 2), a pattern printing method by letterpress printing (Patent Document 3), and the like have been proposed. In particular, the method using relief printing is excellent in pattern formation accuracy and film thickness uniformity, and is most suitable as a method for producing an organic EL element by printing.

  An example of the manufacturing process of the organic EL element by the relief printing method is shown below. First, ink is applied to the surface of an anilox roll having fine holes. Next, the ink applied per unit area of the anilox roll is made uniform by scraping off excess ink on the anilox roll surface with a doctor. Then, the ink on an anilox roll is transcribe | transferred on the printing plate patterned according to the pixel shape of the organic EL element. Finally, the light-emitting layer of the organic EL element is formed by transferring the ink thin film on the printing plate onto the substrate.

  FIG. 1 illustrates an example of a printing process for forming a light emitting portion by a relief printing method. Ink is stored in the inking unit 103 shown in FIG. After the ink is supplied to the anilox roll 104 in the ink pan 103, the excess ink on the anilox roll 104 is scraped off by the doctor 105, and the ink is stored only inside the hole. The ink inside the hole is transferred onto the image forming portion of the relief plate 101 wound around the plate cylinder 102 that rotates relative to the anilox roll 104, and forms a thin film of ink there. Further, the thin film formed on the image forming unit is transferred onto the printing substrate 106 that moves relative to the plate cylinder 102.

  When an organic EL element is produced by a relief printing method, the transfer pattern on the printing plate is arranged with a plurality of transfer patterns for forming the same color light emitting part among a plurality of light emitting parts constituting each pixel of the organic EL element. The organic light emitting layer is obtained by sequentially printing the light emitting portions that emit light of the respective emission colors.

  As described above, in the letterpress printing method, an ink thin film is formed on the letterpress by transferring ink from the anilox roll to the letterpress. However, in the conventional letterpress printing apparatus, the ink on the letterpress at the initial stage of printing is printed. Since the film thickness is not constant and is unstable with respect to the transfer to the substrate to be printed, there is a problem that the ink film thickness formed on the substrate to be printed is not uniform and a transfer defect occurs.

  Therefore, in the relief printing method, preliminary transfer is performed a plurality of times before printing, so that the ink film thickness on the relief plate is uniformly stabilized and the transfer accuracy to the printing substrate is improved. However, since an organic EL element uses an expensive glass substrate and ink, there is a problem that performing preliminary transfer a plurality of times before printing leads to an increase in running cost.

Japanese Patent Laid-Open No. 10-12377 JP 2001-93668 A JP 2001-155858 A

  The present invention has been made to solve the above-mentioned problems, and by carrying out preliminary transfer of relief printing ink without using a substrate to be printed, a uniform pattern free from transfer defects can be inexpensively formed on the substrate to be printed. An object of the present invention is to provide a relief printing apparatus that can be transferred to the surface and a method for producing an organic EL panel using the relief printing apparatus.

As means for solving the above-mentioned problems, the invention described in claim 1 includes a relief plate on a support base, a rotary plate cylinder for installing the relief plate, and an ink supply unit for supplying ink to the relief plate. A relief printing apparatus comprising a relief printing unit for placing the printing substrate and transferring the ink on the relief plate to the printing substrate,
A preliminary transfer portion is provided for transferring ink on the relief printing plate in place of the substrate to be printed at the time of preliminary transfer, and the material of the surface to be transferred of the preliminary transfer portion is the same material as the surface of the substrate to be printed. Ah is, the pattern shape of the transfer surface is a relief printing apparatus, characterized in that the pattern shape and the shape of the surface of the substrate to be printed.

Further, in the invention according to claim 2 , the preliminary transfer portion rubs the surface of the rotating roll, a liquid storage tank for storing the cleaning liquid, a rotating roll whose upper surface is exposed from the cleaning liquid and whose lower surface is immersed in the cleaning liquid. The cleaning liquid doctor arranged in the cleaning liquid, the cleaning liquid external doctor arranged outside the cleaning liquid so as to further rub the surface of the rotating roll rubbed by the cleaning liquid doctor, and the rotating roll rubbed by the cleaning liquid external doctor and a drying nozzle for blowing nitrogen or clean air to the surface, the upper surface of the rotating roll, Toppan according to claim 1, wherein the relief plate is brought into contact with it, characterized in that to transfer the ink supplied onto the convex plate It is a printing device.

The invention according to claim 3, claim 2, characterized in that it comprises a cleaning liquid supply nozzle for supplying a cleaning liquid, and a overflow pipe for overflow cleaning fluid from said reservoir to said liquid storage tank This is a relief printing apparatus.

According to a fourth aspect of the present invention, when the ink is transferred by bringing the relief plate into contact with the upper surface of the rotary roll, the cleaning liquid supplied by the cleaning liquid supply nozzle into the liquid storage tank The letterpress printing apparatus according to claim 3 , wherein the letterpress is discharged onto the surface of the rotating roll onto which the toner has been transferred.

In the invention according to claim 5 , the surface to be transferred of the preliminary transfer portion has the same shape as the pattern shape by the pixel electrode, the partition, and the hole transport layer provided on the substrate constituting the organic EL panel. It is a manufacturing method of the organic electroluminescent panel characterized by forming the organic light emitting layer which comprises an organic electroluminescent panel using the relief printing apparatus in any one of Claims 1-4 .

In the invention according to claim 6 , the organic light-emitting layer is formed after performing the preliminary transfer of the ink for forming the organic light-emitting layer from the letterpress to the preliminary transfer device 1 to 20 times using the letterpress printing apparatus. 6. The method for producing an organic EL panel according to claim 5 , wherein the forming ink is transferred to the substrate to be printed.

  According to the first aspect of the present invention, while the preliminary transfer portion is in contact with the relief printing plate and the ink is preliminarily transferred to the preliminary transfer portion, the ink is not transferred to the substrate to be printed and the substrate to be printed is consumed. Not.

  Therefore, the ink transfer can be stabilized by the preliminary transfer without consuming the substrate to be printed at the initial stage of printing where the ink transfer is unstable, and the ink can be stably transferred to the substrate to be printed.

  In addition, since the contact surface between the relief printing plate on which the ink thin film is formed and the preliminary transfer portion is made of the same material as the substrate to be printed, transfer stability equivalent to that of the preliminary transfer using the substrate to be printed can be obtained. As a result, it is possible to manufacture a high-quality organic EL panel in which transfer variation is suppressed.

In addition , since the surface of the preliminary transfer portion that contacts the ink thin film forming portion on the surface of the relief printing plate has the same surface shape as the substrate to be printed, the ink transfer state from the relief printing surface to the surface of the preliminary transfer portion can be transferred to the printing substrate. Can be close to the state. Therefore, transfer stability equivalent to preliminary transfer using a substrate to be printed can be obtained, and a high-quality organic EL panel with suppressed transfer variation can be manufactured.

In the second aspect of the present invention, the ink transferred to the surface of the rotating roll is scraped off in the cleaning liquid by the doctor in the cleaning liquid, so that the scraped coating liquid is not dried and contaminates the rotating roll. Further, the surface of the rotary roll from which ink has been scraped off by the doctor in the cleaning liquid is surely dried because the cleaning liquid adhering to the surface is scraped off by the doctor outside the cleaning liquid and nitrogen or clean air is blown. This makes it possible to keep the surface of the rotating roll clean and dry.

  In addition, by preliminarily transferring to a clean and dry rotating roll, the ink formed on the relief plate is in an optimum state for transfer. This makes it possible to produce an organic EL element with high film thickness uniformity.

  Furthermore, the substrate used for the preliminary transfer in the past is not necessary, and the process can be reduced.

In the third aspect of the present invention, the cleaning liquid is supplied to the liquid storage tank and the cleaning liquid overflows from the liquid storage tank while the ink thin film formed on the relief printing plate is preliminarily transferred onto the rotating roll. The cleaning liquid in the liquid tank is appropriately replaced so that it does not become so dirty that the cleaning effect is lost.

In the invention according to claim 4 , since the cleaning liquid supplied to the liquid storage tank is applied to the surface of the rotating roll onto which the ink has been transferred, a higher cleaning effect can be obtained.

In the invention according to claim 5 , since the organic light emitting layer is formed on the translucent substrate of the organic EL panel using the relief printing apparatus according to any one of claims 1 to 4 , the organic material using the preliminary transfer portion is used. In the preliminary transfer of the light emitting layer forming ink, an expensive translucent substrate is not consumed by the preliminary transfer. Therefore, an organic light emitting layer with high film thickness uniformity can be formed on a light transmitting substrate at a low cost.

In the invention according to claim 6 , the organic EL panel is characterized in that the preliminary transfer from the relief plate inked in the relief printing portion to the preliminary transfer portion is carried out 1 to 20 times and then transferred to the substrate to be printed. By carrying out preliminary transfer in the manufacturing method, there is an effect of improving the transfer stability from the relief printing plate to the substrate to be printed, which makes it possible to produce an organic EL panel with high film thickness uniformity. In addition, when a rotating roll immersed in a cleaning agent is used for the preliminary transfer portion, the rotating roll after preliminary transfer can be used repeatedly after cleaning, so that the film thickness uniformity can be achieved without using a translucent substrate for preliminary transfer. It is possible to produce an organic EL panel having a high height. This makes it possible to manufacture high-quality products at low cost.

It is the cross-sectional schematic of one Embodiment of the conventional relief printing apparatus. It is a section schematic diagram of one embodiment of a letterpress printer of the present invention. It is the cross-sectional schematic of one Embodiment of the preliminary transfer part which concerns on the relief printing apparatus of this invention. It is a section schematic diagram of one embodiment of an organic EL panel of the present invention.

The relief printing unit 100 of the relief printing apparatus according to the present invention is substantially the same as the conventional relief printing apparatus as shown in FIG. 1, and includes a rotary printing cylinder 102 (corresponding to the printing cylinder in the claims), a printing cylinder. 102, a light-emitting pattern forming relief plate 101 formed around the substrate 102, a moving surface plate 107 that conveys the printing substrate 106, an anilox roll 104 that supplies ink onto the relief plate 101, and an ink supply that supplies ink to the anilox roll 104. It comprises a king unit 103 and a doctor 105 that removes excess ink on the anilox roll 104.

  As shown in FIG. 2, the relief printing apparatus of the present invention includes a preliminary transfer unit 200 that moves along with the moving surface plate 107 in addition to the conventional relief printing apparatus shown in FIG. 1 (the relief printing unit 100 of the present invention). I have. The support base 300 is positioned horizontally below the plate cylinder 102, and the movable surface plate 107 and the preliminary transfer unit 200 are perpendicular to the rotation axis of the plate cylinder 102 on the support base 300 via a guide. It is installed so that it can move horizontally.

  Hereafter, each structure of the relief printing apparatus of this invention is demonstrated in detail.

  As shown in FIG. 2, in the relief printing unit 100 of the present invention, a plate cylinder 102 is disposed on a moving surface plate 107 and is rotatably supported at a fixed position. The relief plate 101 is mounted on the peripheral surface of the plate cylinder 102. The anilox roll 104 is installed in parallel with the rotation axis of the plate cylinder 102 and in contact with the plate surface on the surface of the relief plate 101. The inking unit 103 is installed so that the anilox roll 104 and the supply port of the inking unit 103 are in contact with each other according to the type of the inking unit 103. The substrate to be printed 106 is placed on a moving surface plate 107. The moving surface plate 107 is installed so as to move horizontally in a direction perpendicular to the rotation axis of the plate cylinder 102.

  In the relief printing unit 100 having the above-described configuration, the ink supplied from the inking unit 103 is uniformly held on the surface of the anilox roll 104 as the anilox roll 104 rotates, and then the relief plate 101 attached to the plate cylinder 102 is provided. Transfer to the plate. The printing substrate 106 is fixed on a slidable moving surface plate 107 and moved to the printing start position while adjusting the position by a position adjusting mechanism between the pattern of the relief plate 101 and the pattern forming position of the printing substrate 106. From the printing start position, the substrate to be printed 106 comes into contact with the convex portion of the relief plate 101 and moves in synchronization with the rotation of the plate cylinder 102, and the ink is transferred from the relief plate 101 to a predetermined position on the substrate 106 to be printed. After the ink pattern is formed on the substrate 106 to be printed, a drying process using an oven or the like can be provided as necessary.

  An example of the preliminary transfer unit 200 according to the embodiment of the present invention is shown in FIG. The preliminary transfer unit 200 includes a storage tank 208 for storing the cleaning liquid 213, a rotating roll 201 whose upper surface is exposed from the cleaning liquid 213 and whose lower surface is immersed in the cleaning liquid 213, and the cleaning liquid 213 so as to rub the surface of the rotating roll 201. The cleaning liquid doctor 203 disposed in the cleaning liquid, the cleaning liquid external doctor 205 disposed outside the cleaning liquid 213 so as to further rub the outer periphery of the rotary roll 201 rubbed by the cleaning liquid doctor 203, and the rotation rubbed by the cleaning liquid external doctor 205 A drying nozzle 207 that blows nitrogen or clean air on the surface of the roll 201 is provided, and ink is transferred from the relief plate 101 on which the ink thin film is formed to the upper surface of the rotating roll 201.

  The preliminary transfer unit 200 includes a cleaning liquid supply nozzle 202 that supplies the cleaning liquid 213 into the liquid storage tank 208, and an overflow pipe 209 that causes the cleaning liquid 213 to overflow from the liquid storage tank 208. It is desirable that the cleaning liquid supply nozzle 202 is disposed toward the surface of the rotary roll 201 to which the ink has been transferred.

  In addition, the preliminary transfer unit 200 includes a drain pipe 215 having a drain valve 211 at the bottom of the liquid storage tank 208. When the drain valve 211 is opened, the drain pipe 215 discharges the cleaning liquid 213 from the bottom of the liquid storage tank 208, and when the drain valve 211 is closed, the cleaning liquid 213 is stored in the liquid storage tank 208.

The material of the surface of the rotary roll 201 (the surface to be transferred of the preliminary transfer portion) is preferably the same material as the outermost surface of the substrate to be printed. That is, by using the same material, preliminary transfer can be performed in the same environment as the state (characteristics) of the ink printed on the substrate to be printed, and the ink transfer (printing quality) in the preliminary transfer remains as it is. The print quality can be confirmed.
The outermost surface of the substrate to be printed used in the present invention is preferably an organic compound, but is not particularly limited.

  In addition, it is desirable that the pattern shape of the surface of the rotating roll 201 (the surface to be transferred of the preliminary transfer portion) is the same as the surface pattern shape of the substrate to be printed. In other words, by making the pattern shape of the surface to be transferred in the preliminary transfer portion the same as the surface pattern shape of the substrate to be printed, the ink, the plate, and the pattern become the same printing environment, and printing with higher accuracy by preliminary transfer The print quality of the substrate can be confirmed. At this time, it is desirable that the patterning on the surface of the rotating roll be in the entire region of the surface with which the letterpress comes into contact, but this is not restrictive.

  Next, a preliminary transfer process from the relief plate 101 by the preliminary transfer unit 200 will be described.

  First, the cleaning liquid 213 is stored in the liquid storage tank 208. Next, the ink is transferred from the relief plate 101 on which the ink thin film is formed on the rotating roll 201 that is rotating.

  At this time, it is desirable to supply the cleaning liquid 213 from the cleaning liquid supply nozzle 202 again. Accordingly, when the cleaning liquid 213 is supplied while being discharged to the rotary roll 201, a higher cleaning effect can be expected.

The preliminary transfer unit 200 moves with the moving surface plate 107 on the support base 300 to a position where the relief plate 101 on the plate cylinder 102 and the rotary roll of the preliminary transfer unit are in contact with each other. Then, before the transfer process to the printing substrate 106 on the moving surface plate 107, the rotation of the anilox roll 104, the rotation of the plate cylinder 102, and the rotation of the rotary roll 201 were synchronized and transferred from the anilox roll 104. The ink on the relief plate 101 is transferred onto the rotary roll 201 of the preliminary transfer unit 200.
In the preliminary transfer process from the relief plate 101 to the rotating roll 201, it is desirable to adjust the number of times of preliminary transfer in accordance with necessary printing characteristic values such as the number of printed sheets, the film thickness, the plate line width, and the ink viscosity. In order to improve, it is desirable to carry out at least twice. Here, one preliminary transfer step means that the entire end surface of the relief plate 101 comes into contact with the rotary roll 201.

  The rotating roll 201 to which the ink has been transferred from the relief plate 101 is immersed in the cleaning liquid 213 as the rotating roll 201 rotates, and the ink in the rotating roll 201 is scraped off by the cleaning liquid doctor 203 in the liquid storage tank 208. Since the ink is in the cleaning liquid 213, the ink scraped off does not dry and contaminate the rotary roll 201 or the doctor 203 in the cleaning liquid.

  Next, the cleaning liquid 213 attached to the rotary roll 201 is scraped off by the cleaning liquid external doctor 205 outside the cleaning liquid 213. Thereafter, the surface of the rotating roll 201 is dried by blowing nitrogen or clean air from the drying nozzle 207 toward the surface of the rotating roll 201.

  It is desirable that the cleaning liquid 213 is always supplied from the cleaning liquid supply nozzle 202 during the preliminary transfer of ink. Since the surplus is overflowed by the overflow pipe 209, the cleaning liquid 213 in the liquid storage tank 208 is appropriately replaced so that it does not become so dirty that the cleaning effect is lost. The cleaning liquid supply nozzle 202 and the drying nozzle 207 may have a plurality of cylindrical tubes arranged in parallel, or may have a nozzle shape having a slit having the same length as the width of the rotary roll 201.

  Further, the drain valve 211 is opened as appropriate, the cleaning liquid 213 in the liquid storage tank 208 is discharged from the drain pipe 215, and the cleaning liquid 213 is supplied to the liquid storage tank 208 by the cleaning liquid supply nozzle 202, thereby cleaning the liquid 213 in the liquid storage tank 208. It is desirable that can be replaced with a new solution.

  The anilox roll 104 according to the embodiment of the present invention supplies ink to the relief plate 101 while rotating at the same peripheral speed as the peripheral speed of the plate cylinder 102. The anilox roll 104 can be made of chrome or ceramics, and it is desirable that the outer surface of the anilox roll 104 be formed with patterns such as fine holes, recesses, and cells for holding ink. .

  The inking unit 103 according to the embodiment of the present invention includes an ink reservoir that immerses the lower peripheral surface portion of the anilox roll 104, a coater such as a dripping type inking unit, a fountain roll, a die coater, a cap coater, and the like. Combinations and the like can be used. Further, it is desirable that an ink replenishing device (not shown) for replenishing ink and an ink tank (not shown) for storing ink are connected to the inking unit 103.

  In order to supply ink uniformly on the anilox roll 104, it is desirable to provide a doctor 105. The doctor 105 has a blade shape or a roll shape, and any of them may be used. When the inking unit 103 is an ink reservoir, the doctor 105 is positioned between the ink reservoir and the contact point between the anilox roll 104 and the relief plate 101 in the rotation direction of the anilox roll 104, and scraped ink. Is preferably allowed to fall into the ink reservoir.

  The material of the base material used for the relief plate 101 according to the embodiment of the present invention is only required to have mechanical strength against printing, such as polyethylene, polystyrene, polybutadiene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyamide, Known synthetic resins such as polyethersulfone, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, and polyvinyl alcohol, known metals such as iron, copper, and aluminum, or laminates thereof can be used.

  As the base material constituting the relief plate 101, one that maintains high dimensional stability is desirable, and a metal is suitably used as the material used as the base material. Examples of the metal used as the base material include iron, aluminum, copper, zinc, nickel, titanium, chromium, gold, silver, alloys thereof, and laminates. In particular, iron is the main component in terms of workability and economy. The steel base material and aluminum base material which can be used can be used suitably.

  When the plate surface of the relief plate 101 is formed of a resin, as a method for forming the protrusions on the plate surface, a photolithography method using a positive photosensitive resin, a photolithography method using a negative photosensitive resin, injection molding, a relief plate Various pattern molding methods such as printing method, intaglio printing method, lithographic printing method, stencil printing method, laser ablation method, etc. can be used. From the viewpoint of high definition of pattern, photolithography method using photosensitive resin In addition, a photolithography method using a negative photosensitive resin capable of forming a relief with the required accuracy is most desirable.

  When the photolithographic method using a photosensitive resin is applied as the convex pattern forming method, the convex of the relief plate 101 is formed from a plate-shaped photosensitive resin laminate in which a base material layer, a reflection suppressing layer, and a photosensitive resin layer are sequentially laminated. It is most desirable to form the part. As a method for molding the photosensitive resin layer, a known method such as an injection molding method, a protruding molding method, a laminating method, a bar coating method, a slit coating method, or a comma coating method can be used.

  When the plate surface of the relief plate 101 is formed of a resin, the resin to be used is only required to have solvent resistance to ink. In addition to rubbers such as propylene rubber and urethane rubber, polyethylene, polystyrene, polybutadiene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyamide, polyether sulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyvinyl alcohol, etc. Synthetic resins, their copolymers, cellulose derivatives, etc., fluoroelastomers, polytetrafluoroethylene, polyvinylidene fluoride, poly (vinylidene fluoride) and their It is possible to select one or more of a fluorine-based resin such as polymer.

  The relief plate 101 according to the embodiment of the present invention is used by winding the relief plate 101 having the projection pattern formed on the substrate as described above around the plate cylinder 102. A convex pattern may be formed on the plate cylinder 102.

  The ink to be used is adjusted to a suitable viscosity in consideration of the coating from the ink supply device 103 to the anilox roll 104 and the transfer from the anilox roll 104 to the relief plate 101, and the viscosity of the ink should be 2 to 120 mPa · s. desirable. In the relief printing method used in the present embodiment, the ink is first transferred from the anilox roll 104 onto the relief plate 101, but after the ink is transferred from the anilox roll 104 onto the relief plate 101 at a viscosity of 120 mPa · s or more, Ink is not leveled sufficiently on the relief plate 101, causing unevenness. In addition, when the pressure is 2 mPa · s or less, the mottling unevenness is likely to occur in the pixel, causing the unevenness.

  The amount of ink transferred from the anilox roll 104 onto the relief plate 101 is determined by the thickness of the film to be formed on the printing substrate 106. By adjusting the ink density and the cell volume of the anilox roll 104, the amount of ink is transferred onto the relief plate 101. It is desirable to make the amount of ink transferred constant.

  In the transfer of ink from the anilox roll 104 to the relief plate 101, if the preliminary transfer portion 200 does not exist, the thickness of the ink thin film supplied onto the relief plate 101 at the initial stage of the printing process is not constant. Therefore, when the transfer to the printing substrate 106 is performed at the initial stage of the printing process, the film thickness uniformity of the ink thin film formed on the printing substrate 106 is low, and the transfer defect is caused. May occur. Therefore, if the preliminary transfer to the printing substrate 106 is performed, the above-mentioned transfer problem at the initial stage of the printing process can be solved. However, in this case, an expensive printing substrate used for the preliminary transfer is used. 106 leads to an increase in cost. Therefore, in the method for manufacturing an organic EL element using the relief printing method of the present invention, the preliminary transfer by the preliminary transfer unit 200 is performed before the transfer to the printing substrate 106, so that the printing substrate 106 is not used. Preliminary transfer can be performed, and problems such as transfer defects at the initial stage of the printing process can be solved.

  FIG. 4 shows a schematic cross-sectional view of an organic EL panel manufactured by the relief printing apparatus of FIG.

  The organic EL panel 400 includes a translucent substrate 401, a transparent conductive layer 402, a hole injection layer 403, an organic light emitting layer 404, a cathode layer 405, and a partition wall 406 that partitions pixels.

In the organic EL panel 400, a glass substrate or a plastic film or sheet can be used as the translucent substrate 401. 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. Also, other gas barrier films such as a ceramic vapor-deposited film, polyvinylidene chloride, polyvinyl chloride, ethylene-vinyl acetate copolymer saponified product, etc. are laminated on the side of the transparent substrate 401 where the transparent conductive layer 402 is not formed. May be.

  As a material for forming the transparent conductive layer 402, a composite oxide of indium and tin (hereinafter referred to as ITO) can be given. In addition, a semi-transparent metal such as aluminum, gold, or silver, or an organic compound such as polyaniline may be used.

  As a material for forming the hole injection layer 403, a conductive polymer material such as a polyaniline derivative, a polythiophene derivative, a polyvinylcarbazole derivative, or a mixture of poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid may be used. good.

  The organic light emitting layer 404 is a layer that emits light when a voltage is applied, and is a layer formed by using the relief plate 101 according to the present invention by the apparatus shown in FIG. 2, and is a layer formed by drying the coating liquid described above. It is.

  As a material for forming the cathode layer 405, a material corresponding to the light emitting characteristics of the organic light emitting layer 404 may be used. For example, simple metals such as lithium, magnesium, calcium, ytterbium, and aluminum, oxides thereof, and gold, silver An alloy with a stable metal such as is used. Alternatively, a conductive oxide such as indium, zinc, or tin can be used.

  In order to form the transparent conductive layer 402 and the hole injection layer 403 on the translucent substrate 401, a known method may be used. After forming these, organic light emission is performed using the apparatus shown in FIG. A layer 404 is formed, and a cathode layer 405 is further formed thereon. The cathode layer 405 can be formed by a known means such as an ink jet method in addition to the vacuum vapor deposition method. The transparent conductive layer 402, the hole injection layer 403, the organic light emitting layer 404, the cathode layer 405, and the partition wall 406 are sealed by a sealing substrate 408 attached to the light transmitting substrate 401 through an adhesive layer 407. .

  The organic EL panel 400 having the above configuration can be manufactured as follows using the printing apparatus shown in FIG. In other words, the translucent substrate 401 is used as the substrate to be printed 106, and the ink for forming the organic light emitting layer 404 is transferred to the substrate 106 as the ink for forming the organic light emitting layer on the preliminary transfer unit 200 by the printing apparatus of FIG. After the preliminary ink transfer, the organic light emitting layer 404 can be formed on the light transmitting substrate 401 by transferring the organic light emitting layer forming ink to the substrate 106 to be printed. Here, the preliminary transfer of the organic light emitting layer forming ink is desirably performed 1 to 20 times.

  Although the Example and comparative example which concern on the manufacturing method of the organic electroluminescent panel 400 of this invention are shown below, it is not restricted to this.

<Example 1>
(Process for producing printed substrate 106)
A thin film transistor functioning as a switching element provided on a support, a planarizing layer formed thereabove, and a planarized layer formed as a planarized layer and connected to the thin film transistor through a contact hole is provided as a substrate 106 to be printed. An active matrix substrate having a pixel electrode is used. One side of the pixel size is 150 μm square, and the size of the RGB sub-pixel is 50 × 150 μm.

  A partition wall was formed so as to cover the end of the pixel electrode provided on the active matrix substrate and partition the pixel. The partition walls are formed by depositing a positive resist ZWD6216-6 manufactured by ZEON Corporation on the entire surface of the active matrix substrate with a spin coater so that the film thickness after drying is 1 μm, and then by photolithography. Partition walls having a line width of 20 μm were formed on four sides.

  A poly- (3,4) -ethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) 1.5 wt% aqueous solution with a film thickness of 100 nm is formed on the pixel electrode as a hole transport layer by spin coating. did. Further, the PEDOT / PSS thin film thus formed was dried at 100 ° C. under reduced pressure for 1 hour to produce a substrate to be printed 106.

(Process for producing organic light-emitting layer forming ink)
The following polymeric organic light-emitting inks comprising three colors of red, green, and blue (R, G, B) were prepared.
Red luminescent ink (R): 1 wt% xylene solution of polyfluorene derivative
(Red light-emitting material manufactured by Sumitomo Chemical Co., Ltd., trade name Red1100)
Green luminescent ink (G): 1 wt% xylene solution of polyfluorene derivative
(Green light-emitting material manufactured by Sumitomo Chemical Co., Ltd., trade name Green 1300)
Blue luminescent ink (B): 1 wt% xylene solution of polyfluorene derivative
(Blue light-emitting material manufactured by Sumitomo Chemical Co., Ltd., trade name Blue 1100)

(Manufacturing process of letterpress 101)
An antireflective layer was formed by applying an acrylic binder resin solution kneaded with a black pigment onto a 42 nickel material having a thickness of 250 μm as a base material and applying a dry film thickness of 10 μm.

Next, a photosensitive resin composition was prepared by kneading materials having the following composition, and melt-coated on the antireflection layer of the base material so that the total thickness was 310 μm.
Main agent: Water-soluble polyamide resin Radical polymerizable monomer: Dipentaerythritol hexakisacrylate Photopolymerization initiator: 2,2-dimethoxy-1,2-diphenylethane-1-one
(Ciba Specialty Chemicals)

  Next, a polyvinyl alcohol solution is applied to a 125 μm-thick polyethylene terephthalate film (manufactured by Teijin DuPont Films Co., Ltd.) so as to have a dry film thickness of 1 μm, and laminated with the surface on which the photosensitive resin composition is melt-coated. A photosensitive relief printing plate was prepared.

  Using a synthetic quartz-based chromium mask as the original pattern of the relief plate 101, and exposing the photosensitive relief plate using this mask set in a proximity exposure apparatus, the relief plate 101 on which the desired pattern is formed is produced. did.

(Printing process of organic light emitting layer forming ink)
The relief plate 101 was fixed to the plate cylinder 102 of the sheet-fed printing apparatus. Next, the polymer organic light-emitting ink was supplied to the inking unit tank 103, and the anilox roll 104 was rotated to ink the entire surface. The anilox roll 104 was a 600 line / inch anilox roll. Thereafter, excess ink on the anilox roll 104 was scraped off by a doctor 105 and inked into the convex pattern portion of the relief plate 101.

Before the ink on the relief printing plate 101 inked as described above is transferred to the printing substrate 106, the ink is preliminarily transferred onto a rotating roll 201 that has been rotated. The rotating roll used was a rotating roll whose surface was patterned in the same shape as the substrate to be printed, and whose surface was coated with the same material as the outermost surface of the substrate to be printed. After the preliminary transfer, the convex pattern portion of the relief plate 101 was inked in the same manner as in the printing process of the organic light emitting layer forming ink. In this example, such preliminary transfer was performed 10 times.

  After carrying out the preliminary transfer as described above, the printing process of the ink for forming the organic light emitting layer is repeated again, and the inked relief plate 101 is pressed against the substrate to be printed 106, whereby the stripe pattern is formed on the substrate to be printed 106. Printed. By repeating this step for each of the red organic light emitting layer, the green organic light emitting layer, and the blue organic light emitting layer, an organic light emitting layer pattern was obtained. After printing for each color, drying was performed in an oven at 130 ° C. for 1 hour.

  The average film thickness in the first printed panel for each color of the pattern formed as described above was about 70 nm, and the film thicknesses 3 and 3σ in the panel were both about 8 nm.

  Further, an organic EL panel 400 was fabricated by forming a calcium film of 10 nm and a silver film of 300 nm by vacuum deposition on a polymer organic light emitting layer formed by printing, and then sealing with a glass cap.

  When the lighting display of the organic EL panel 400 was confirmed, good light emission was obtained on the entire panel surface.

<Comparative Example 1>
An organic EL panel was produced in the same manner as in Example 1 by using a preliminary transfer roll 201 that was made of the same material as the outermost surface of the substrate to be printed but was not patterned.

  The average film thickness in the second panel printed for each color of the formed pattern, the range, and 3σ were all the same as in the example, but the film thickness was the first in the organic EL panel printing after the preliminary transfer. As a result, the transfer was unstable. Moreover, when the lighting display was confirmed about the organic electroluminescent panel produced in this way, favorable light emission was obtained in the whole panel surface.

<Comparative Example 2>
Preliminary transfer was performed not on the rotating roll 201 but on a glass substrate, and an organic EL panel was produced in the same manner as in Example 1.

  The average film thickness in the third panel printed for each color of the formed pattern, the range, and 3σ all obtained the same results as in the examples, but the film thickness up to the second sheet in organic EL panel printing after preliminary transfer As a result, the transfer was unstable. Moreover, when the lighting display was confirmed about the organic electroluminescent panel produced in this way, favorable light emission was obtained in the whole panel surface.

<Comparative Example 3>
An organic EL element was produced in the same manner as in the previous examples without performing preliminary transfer.

  It was confirmed that the average film thickness in the panel, the range, and 3σ of each color of the formed pattern were deteriorated as compared with the examples. Moreover, when the lighting display confirmation was performed about the organic electroluminescent panel produced in this way, the light emission failure and light emission nonuniformity resulting from the transfer defect were confirmed.

  Table 1 shows the printing characteristic evaluation results of Example 1 and Comparative Examples 1 to 3.

DESCRIPTION OF SYMBOLS 100 ... Letterpress printing part 101 ... Letterpress 102 ... Plate cylinder 103 ... Inking unit 104 ... Anilox roll 105 ... Doctor 106 ... Printed substrate 107 ... Moving surface plate 200 ... Preliminary transfer part 201 ... Rotating roll 202 ... Cleaning liquid supply nozzle 203 ... In-cleaning doctor 204 ... Doctor holder 205 ... External cleaning liquid doctor 206 ... Doctor holder 207 ... Drying nozzle 208 ... storage tank 209 ... overflow pipe 210 ... cleaning liquid supply valve 211 ... drain valve 212 ... nitrogen or clean air supply valve 213 ... cleaning liquid 214 ... transferred Ink 215 ... Drain tube 300 ... Support base 400 ... Organic EL panel 401 ... Translucent substrate 402 ... Transparent conductive layer 403 ... the hole injection layer 404 ... organic emission layer 405 ... cathode layer 406 ... partition wall 407 ... adhesive layer 408 ... sealing substrate

Claims (6)

On the support base, a relief plate, a rotary plate cylinder that installs the relief plate, an ink supply unit that supplies ink to the relief plate, and a substrate to be printed are placed and the ink on the relief plate is transferred to the substrate to be printed. A letterpress printing apparatus comprising: a letterpress printing unit;
A preliminary transfer portion is provided for transferring ink on the relief printing plate in place of the substrate to be printed at the time of preliminary transfer, and the material of the surface to be transferred of the preliminary transfer portion is the same material as the surface of the substrate to be printed. Ah is, relief printing device pattern shape of the transfer surface, characterized in that it is a pattern the same shape of the surface of the printed substrate. The preliminary transfer unit includes a liquid storage tank for storing the cleaning liquid, a rotating roll whose upper surface is exposed from the cleaning liquid and a lower surface is immersed in the cleaning liquid, and a doctor in the cleaning liquid disposed in the cleaning liquid so as to rub the surface of the rotating roll. And a cleaning liquid external doctor disposed outside the cleaning liquid so as to further rub the surface of the rotating roll rubbed by the cleaning liquid doctor, and a drying nozzle for blowing nitrogen or clean air onto the surface of the rotating roll rubbed by the cleaning liquid external doctor, wherein the the upper surface of the rotating roll, letterpress device according to claim 1, wherein the relief plate is brought into contact with it, characterized in that to transfer the ink supplied onto the convex plate. The relief printing apparatus according to claim 2 , comprising a cleaning liquid supply nozzle for supplying a cleaning liquid into the liquid storage tank and an overflow pipe for overflowing the cleaning liquid from the liquid storage tank. When transferring the ink by bringing the relief plate into contact with the upper surface of the rotating roll, the cleaning liquid supply nozzle discharges the cleaning liquid supplied into the liquid storage tank onto the surface of the rotating roll to which the ink has been transferred. The relief printing apparatus according to claim 3, wherein The transfer surface of the preliminary transfer portion, a pixel electrode provided on the substrate constituting the organic EL panel, barrier ribs, according to any one of claims 1 to 4 which is a pattern the same shape by a hole transport layer An organic EL panel manufacturing method comprising forming an organic light emitting layer constituting an organic EL panel using a relief printing apparatus. Using the relief printing device, after the pre-transfer of ink for forming the organic light-emitting layer was performed 1-20 times for the pre-transfer part from the relief plate, transferring the organic light emitting layer forming ink to the substrate to be printed The method for producing an organic EL panel according to claim 5 .