JP4808395B2 - Printing device - Google Patents

Description

The present invention ejects a resin material to a substrate, to a printing device used for printing how to form a resin film.

  Conventionally, a resin film such as a polyimide film has been used for an alignment film of a liquid crystal panel. The resin film is formed by applying a resin material coating liquid onto a substrate with a printing apparatus such as a flexographic printing apparatus or an ink jet printer to form a coating layer.

  The coating liquid is made liquid by dissolving a resin material, which is a polyimide resin, in an organic solvent. When the coating layer is heated and dried, the organic solvent in the coating layer is evaporated and removed. Since the polyimide resin is solid at room temperature, the polyimide resin remains even if the organic solvent is removed, and a polyimide resin film is formed on the substrate.

  Inkjet printers have a limited range in which a coating solution can be applied at one time. Therefore, when forming an alignment film on a large substrate, the substrate and the printer head are moved relative to each other, and the printer head is scanned over the substrate. By doing so, an alignment film is formed in a wide region.

  However, it takes time from the time when the coating solution is applied to the first region on the substrate to the time when the coating solution is applied to the last region, and the first applied coating solution is applied to the remaining region. As the organic solvent begins to evaporate while the ink is printed, uneven drying occurs between the first and last areas of the application.

In addition, when printing is performed for each partial area with an ink jet printer, streaks at the boundary of the application area and defects in the alignment film may occur. In order to solve this problem, there is a method of printing so that the areas to be applied partially overlap, but the film thickness of the overlapping part of the coating layer is thicker than the film thickness of the other part of the coating layer. As a result, the film thickness of the resin film becomes uneven. As described above, the conventional printing method is liable to cause problems such as uneven drying of the alignment film and uneven film thickness. When such an alignment film is used, the liquid crystal device characteristics are deteriorated.
JP 2001-305544 A JP 2002-90740 A JP 2002-296593 A JP 2004-223354 A Japanese Patent Laid-Open No. 11-40358 JP 2003-225600 A

The present invention has been created to solve the disadvantages of the prior art, its object is to provide a formable print device a uniform resin film thickness over a wide area.

In order to solve the above problem, the invention according to claim 1 is a printing table on which a printing object is arranged, and a substrate movement for moving the printing object from a conveyance start position on the printing table to a conveyance end position. A printing apparatus that includes an apparatus and a print head that is disposed on the printing stand and that discharges a coating liquid onto the surface of the print object, the print apparatus being at a position downstream of the print head in the moving direction of the print object. the vapor of the humidifying solution a printing apparatus that have a steam generator that emits, the steam generator includes a steam emission surface facing the surface of the printing object, the steam in the steam-emitting surface When a plurality of releasable small holes are provided and the printing object is located directly below the vapor discharge surface, the outer periphery of the area where the small holes are arranged is outside the printing area of the printing object. The small holes are arranged so that Region is constituted wider than the printing area, the printing area is exposed printing apparatus to the vapor of uniformly moisturizing liquid.
Invention of Claim 2 is the printing apparatus of Claim 1, Comprising: The area | region where the said small hole is arrange | positioned has the length of the said moving direction longer than the length of the said moving direction of the said printing area | region, In the printing apparatus, the length in the direction perpendicular to the moving direction is longer than the length in the direction perpendicular to the moving direction of the printing region.
According to a third aspect of the invention, a printing apparatus of any one of claims 1 or claim 2, wherein the steam generator is placed the object to be printed to the steam generating chamber that can carry the The steam generation chamber is a printing device configured to be filled with steam of the humidifying liquid.
A fourth aspect of the present invention is the printing apparatus according to any one of the first to third aspects, wherein a portion of the printing area where the coating liquid is printed is exposed to the vapor of the humidifying liquid. In this state, the printing head is a printing device configured to print the coating liquid on other portions of the printing area.
According to a fifth aspect of the invention, a printing apparatus according to any one of claims 1 to 4, the head moving device for moving the print head substantially vertically to the movement direction of the object to be printed It is a printing apparatus characterized by having.
A sixth aspect of the present invention is the printing apparatus according to the third aspect , wherein the vapor generating chamber is connected to a pump for discharging the gas in the vapor generating chamber.
A seventh aspect of the present invention is the printing apparatus according to any one of the first to sixth aspects, wherein the vapor generating device includes a vapor discharge portion in which the vapor discharge surface is arranged on one side, And a heating unit configured to heat the vapor discharge unit, wherein the vapor discharge unit is configured to be supplied with small droplets of the humidifying liquid.
The invention according to claim 8 is the printing apparatus according to any one of claims 1 to 6 , wherein the steam generation device has a steam discharge portion in which the steam discharge surface is arranged on one surface. The printing apparatus is configured so that the vapor of the humidifying liquid is supplied to the vapor discharge unit.
A ninth aspect of the present invention is the printing apparatus according to any one of the first to eighth aspects , wherein the printing apparatus includes one or more of the steam generators.

  The present invention is configured as described above, and the steam generator is disposed on the downstream side of the print head, so that the coating liquid printed on the printing object is exposed to the steam of the humidifying liquid.

  For example, if a vapor discharge surface is arranged in the vicinity of the coating liquid on the object to be printed, the vapor released from the small holes fills between the coating liquid and the vapor discharge surface, but the vapor generator is arranged in the vapor generation chamber. If the steam generation chamber is filled with steam, the printing object is more efficiently exposed to the steam.

  According to the present invention, when printing is performed on a part of the printing area, the previously printed coating liquid is exposed to the vapor of the humidifying liquid and does not dry, so that the entire printing area is uniformly wet. The coating layer is formed. In addition, even if the previously printed coating liquid is not exposed to the humidifying liquid, if the coating liquid is placed in a humidified atmosphere after the printing of the entire printing area is finished, the whole becomes wet, and the drying process It is hard to cause uneven drying. Moreover, even if the film thickness of the coating layer is not uniform immediately after printing, the coating liquid spreads by its own weight and becomes uniform by making it wet. Thus, according to the present invention, it is possible to form a resin film with good film quality and uniform film thickness.

Reference numeral 1 in FIGS. 1 and 2A denotes a printing apparatus according to the present invention. The printing apparatus 1 includes a printing stand 3, an inkjet unit 50, and a steam generation device 20.
The printing table 3 is elongated, and the planar shape when the printing table 3 is viewed from directly above is a rectangle. One end of the printing table 3 in the longitudinal direction is set as a transfer start position, and the other end is set as a transfer end position. A substrate moving device (not shown) is arranged between the transfer start position and the transfer end position. The substrate 11 (printing object) placed at the transfer start position is transferred to the transfer end position by the substrate moving device.

  The inkjet unit 50 is disposed above the printing table 3 and in the vicinity of the conveyance start position. A vapor generation chamber 26 is disposed adjacent to the ink jet unit 50 above the printing table 3 and on the transport end position side of the ink jet unit 50. The steam generator 20 is disposed in the steam generation chamber 26 at a predetermined distance from the printing table 3, and the substrate 11 sent from the inkjet unit 50 is placed between the printing table 3 and the steam generation device 20. By being inserted, it is configured to be accommodated in the steam generation chamber 26.

  The inkjet unit 50 includes a head moving device 51 and one or more print heads 55. The head moving device 51 moves the print head 55 to a position on the mounting table 3 with respect to the moving direction of the substrate 11. It is configured to reciprocate in the orthogonal direction.

  The print head 55 has a nozzle that discharges the coating liquid. Assuming that the direction in which the print head 55 moves by the head moving device 51 is the Y direction, when the application liquid is applied from the nozzles of the print head 55 with the print head 55 stationary, the maximum application area in the Y direction can be obtained. The length A is shorter than the length B in the Y direction of the area (printing area) to be printed on the substrate 11.

  Accordingly, when the print head 55 is moved forward or backward in the Y direction while the substrate 11 is stationary at the position below the inkjet unit 50, the coating liquid is printed from end to end in the print area along the Y direction. The

  When the substrate 11 is moved in the X direction by the substrate moving device after finishing the coating solution from end to end along the Y direction, the portion where the coating solution is applied is sent into the vapor generation chamber 26. At the same time, the portion where the coating liquid is not applied is disposed below the print head 55.

  Since the width C of the coating liquid printed from end to end in the print area along the Y direction is shorter than the length D in the X direction of the print area, the movement distance of the substrate 11 is the same as the size of the width C. When the above-described coating liquid is printed, the coating liquid having the same width is printed without a gap at a position upstream of the already printed coating liquid. Accordingly, when the above-described printing of the coating liquid and the movement of the substrate 11 are repeated, the coating liquid is printed on the entire surface of the printing area.

The steam generator 20 includes a steam discharge portion 21 and a steam discharge surface 22 which is a surface of the steam discharge portion 21 and is parallel to the substrate 11 moving on the printing table 3.
FIG. 3 is a cross-sectional view of a portion of the printing apparatus 1 where the steam generator 20 is located, cut in the Y direction.

  The vapor discharge part 21 is connected to a humidifying liquid supply system 29. The humidifying liquid of the humidifying liquid supply system 29 is atomized in the humidifying liquid supply system 29, and the droplets (mist) are supplied to the internal space of the vapor discharge unit 21.

  The steam generator 20 has a heating means 25 for heating the steam discharge part 21. Here, the heating means 25 is disposed inside the vapor discharge section 21, and when a small droplet of the humidifying liquid is supplied to the internal space while the vapor discharge section 21 is energized in advance and the vapor discharge section 21 is heated, The humidifying liquid in the droplets evaporates in the internal space, and the vapor of the humidifying liquid is generated.

A plurality of small holes are formed in the vapor discharge surface 22, and the vapor of the humidifying liquid generated in the internal space of the vapor discharge portion 21 is uniformly discharged from each small hole. In the region where the small holes of the vapor discharge surface 22 are provided, the length in the X direction is longer than the length in the X direction of the printing region, and the length in the Y direction is longer than the length in the Y direction of the printing region. 2 ( b ), when the substrate 11 is positioned directly below the vapor discharge surface 22, the outer periphery of the area where the small holes are arranged is positioned outside the printing area, and is located in each part of the printing area. Is uniformly exposed to the vapor of the humidifying liquid. The steam generated from the steam discharge surface 22 fills the internal space of the steam generation chamber 26 and a humidified atmosphere is formed.

Next, a process of forming a resin film on the substrate 11 using the printing apparatus 1 will be described.
When a humidified atmosphere is formed in the steam generation chamber 26 in advance and the above-described coating liquid is printed, the previously printed coating liquid is humidified when printing is performed on the remaining portion of the printing area. Placed in. Reference numeral 14 in FIG. 3 indicates a coating solution placed in a humidified atmosphere.

  The coating solution 14 is composed of a non-volatile resin material such as a polyimide resin dissolved in a coating solution solvent that dissolves the resin material, whereas the humidifying solution is a low-boiling component of the coating solution solvent. Alternatively, the solvent is composed of a solvent having a boiling point equal to or lower than that of the coating solution solvent, and the humidified atmosphere prevents the coating solution solvent from evaporating even if the humidifying solution evaporates.

  Accordingly, the coating liquid 14 printed earlier is not dried while the coating liquid is printed on the remaining portion of the printing area, and remains wet. For example, the coating liquid 14 is printed in an overlapping manner. Even so, the coating liquid 14 spreads by its own weight, and a coating layer of the coating liquid 14 having a uniform film thickness is formed in the printing region.

  When the substrate 11 on which the coating layer has been formed is carried into the drying device (not shown) from the printing device 1 (not shown) and heated to a temperature higher than the boiling point of the solvent for the coating solution, A certain polyimide resin does not evaporate, but the solvent for the coating liquid and the humidifying liquid, which are volatile components, evaporate.

  Since the coating layer after being swollen in a humidified atmosphere has a uniform distribution of the evaporation component in the coating layer, when the volatile component evaporates, the drying proceeds uniformly in each part of the coating layer, and uneven drying does not occur. . Since the drying unevenness does not occur, the coating layer after drying is not only uniform in film thickness, but also the film quality is excellent.If the coating layer is further heat-treated, the film quality is good and a polyimide resin film with a uniform film thickness is obtained. can get.

In general, since the polyimide resin after heat treatment is solid at room temperature, the resin film after the solvent for the coating layer and the humidifying liquid are removed does not have fluidity and is solid at room temperature.
If this resin film is subjected to an alignment treatment such as a rubbing treatment, it can be used as an alignment film for a liquid crystal panel.

  The above describes the case where a humidified atmosphere is formed in the steam generation chamber 26 in advance, and the portion on which the coating liquid has been printed is placed in the humidified atmosphere while printing the coating liquid on the other portion of the printing area. However, the present invention is not limited to this.

After sequentially printing in the print area, the print area may be positioned in the steam generation chamber 26, and the coating liquid printed in the print area may be exposed to the vapor of the humidifying liquid all at once.
In addition, after printing the coating liquid in order on the print area, the part that was printed early is printed earlier than the part without printing on the print area. It is also possible to place the part where the is performed in a humidified atmosphere at a later time.

  The case where the printed coating liquid is exposed all at once to the vapor of the humidifying liquid will be described in detail. The above-mentioned coating liquid is printed without forming a humidified atmosphere inside the steam generation chamber 26, and is applied to all the printing areas. When the coating liquid is printed and the entire print area is disposed in the steam generation chamber 26, the humidified liquid is discharged to form a humidified atmosphere.

  In this case, the coating liquid of the previously printed part dries while the remaining part is printed, but later swells and wets by being placed in a humidified atmosphere together with the remaining part of the coating liquid. Thus, a coating layer having a uniform thickness is formed by spreading due to its own weight. Even if the entire printing area is placed in a humidified atmosphere after printing is completed, the film quality and film thickness are uniform even when the whole is in a wet state so that drying unevenness does not occur in the subsequent drying process. A membrane is obtained.

  The above is a case where one steam generator 20 is provided. However, the number of steam generators is not limited to one, and two or more steam generators are provided on one printing stand 3. It can also be provided.

  For example, the printing apparatus 2 having two or more vapor generation apparatuses will be described. As shown in FIG. 4, the substrate conveyance direction of the first vapor generation chamber 26 that is above the printing table 3 and adjacent to the inkjet unit 50 is illustrated. A second steam generation chamber 46 is disposed on the downstream side, and the second steam generation device 40 is disposed in the second steam generation chamber 46.

  The substrate 11 is inserted between the printing table 3 and the first steam generation device 20, accommodated in the first steam generation chamber 26, and then moved in the X direction. It is inserted between the steam generator 40 and accommodated in the second steam generation chamber 46.

  Since the board | substrate 11 is put in order in the 1st humidification atmosphere formed with the 1st steam generation apparatus 20, and the 2nd humidification atmosphere formed with the 2nd steam generation apparatus 40, the 1st, 2nd If the conditions of the humidified atmosphere (for example, the type, temperature, and vapor pressure of the humidified liquid) are changed, the coating liquid can be processed sequentially in different humidified atmospheres.

The steam generator 20 is not particularly limited as long as it can discharge steam uniformly from the steam discharge surface 22.
Specifically, the vapor discharge part 21 can be composed of a porous ceramic or a porous material such as a sponge-like resin film. In this case, a humidifying liquid supplied from the humidifying liquid supply system 29, The mist of the humidified liquid or the vapor of the humidified liquid is supplied to the internal space having a porous structure. Vapor is released.

  In addition to the porous body, the vapor discharge part is constituted by an internal hollow shower head, the nozzle plate which is one side of the vapor discharge part is used as a vapor discharge surface, and the vapor of the humidifying liquid is generated from the region where the small holes of the nozzle plate are formed. Released.

  The above has described the case where the mist of the humidifying liquid is supplied to the vapor discharge unit 21, but the present invention is not limited to this, and the humidifying liquid is not supplied to the mist but supplied to the vapor discharge unit 21 in a liquid state. May be.

  Further, without generating the vapor of the humidification liquid inside the vapor discharge unit 21, for example, the vapor of the humidification liquid is generated by the humidification liquid supply system 29, and the vapor is supplied to the vapor discharge unit 21, The case of releasing is also included in the present invention. When supplying steam to the steam discharge section 21, if the steam discharge section 21 is heated in advance by the heating means 25, the steam of the humidified liquid is not cooled by the steam discharge section 21, so that the steam is in its internal space. Without being liquefied, it is discharged from the vapor discharge surface 22 as vapor.

  As described above, the state of the humidifying liquid supplied to the vapor discharge unit 21 is not particularly limited. However, when the liquid is supplied in a mist state as compared with the case where it is supplied in a liquid state or supplied as a vapor, the vapor discharge unit 21 is particularly provided. When the is made of a porous body, the humidified liquid easily spreads in the internal space, and as a result, the distribution of the vapor discharge amount becomes uniform on the vapor discharge surface 22.

  If temperature control means such as a temperature raising heater is provided in the steam generation chambers 20 and 40 and the steam generation chambers 20 and 40 are heated to increase the temperature of the humidified atmosphere, the streaks during printing are eliminated. It becomes easy.

  The type of the humidifying liquid is selected according to the solvent for the coating liquid. When the solvent for the coating liquid is a mixed solvent in which two or more kinds of solvents are mixed, the boiling point of the constituent components is for the coating liquid. Low boiling point components below the boiling point of the solvent can be used.

  The resin material is not limited to the polyimide resin, and for example, a polyimide precursor (polyamic acid) can be used as the resin material. When a polyimide precursor is used for the resin material, the coating layer solvent or humidifying liquid is applied to the coating layer by heating the coating layer to a temperature higher than the polymerization temperature at which the polyimide precursor is polymerized in the step of drying the coating layer. In addition to being removed from the polyimide, the polyimide precursor is polymerized, and a resin film of a polyimide resin as the polymer is obtained. The resin material may contain both a polyimide resin and a polyimide precursor, and other types of resins and additives may be added.

  In the above, the case where the coating liquid is printed while moving the print head 55 with respect to the traveling direction of the substrate 11 has been described. However, the present invention is not limited to this. By using a plurality of print heads 55, if the size in the Y direction at which the coating liquid can be applied to the maximum is larger than the size in the Y direction of the print area, printing is performed with the print head 55 fixed. Also good.

  In the above, the case where the resin film is formed in one printing region on the substrate has been described, but the present invention is not limited to this, and a substrate having a plurality of printing regions on the surface is used as a printing object. After forming a coating layer in one or more printing areas, the substrate and the print head 55 are moved relative to each other so that the print head is positioned on the new printing area. A layer is formed. By repeating the printing of the coating layer and the relative movement between the substrate and the print head 55, the coating layer can be formed in all the print areas on the substrate.

  Also in this case, if the printing area where printing has been completed is immediately placed in a humidified atmosphere, while the remaining printing area is being printed, the application liquid in the previously printed printing area will not dry, After printing all the print areas, if each print area is placed in a humidified atmosphere and the coating liquid is swollen, the coating layer of each print area becomes wet, and in each case, the film quality is in each print area. A coating layer having a uniform film thickness is formed.

  For example, when printing two or more colors of ink (for example, red, green, blue) on each pixel of a color filter on a substrate on which a plurality of printing regions (pixels) are arranged, the printing apparatus and printing method of the present invention are used. If used, a dry filter does not cause unevenness in printing, and a color filter with good film quality and uniform film thickness is formed. In addition, when an organic material (for example, a hole injection material or a light emitting material) is printed on each pixel of a substrate on which a transistor (for example, TFT) is arranged in each printing region (pixel), the printing apparatus and the printing method of the present invention. Is used, an organic layer having a good film quality and a uniform film thickness (for example, a hole injection layer or a light emitting layer) is formed.

Side view of an example printing apparatus of the present invention (A), (b): Process drawing explaining the printing method of the present invention Sectional drawing explaining the structure of a steam generator The top view of the printing apparatus of the other example of this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printing apparatus 3 ... Printing stand 11 ... Print object (board | substrate) 20, 40 ... Steam generator (1st, 2nd steam generator) 22, 42 ... Steam discharge surface 26, 46 ... ... Steam generation chamber (first and second steam generation chambers) 50 ... Inkjet section 55 ... Print head

Claims (9)

A printing stand on which a print object is placed;
A substrate moving device for moving the print object from a transfer start position on the printing table toward a transfer end position;
A printing apparatus disposed on the printing table and having a print head for discharging a coating liquid onto the surface of the printing object;
A printing apparatus that have a steam generator which emits steam humidification liquid downstream position than the print head in the moving direction of the printing object,
The steam generator has a steam discharge surface facing the surface of the printing object,
The vapor discharge surface is provided with a plurality of small holes capable of discharging the vapor, and when the object to be printed is located directly below the vapor discharge surface, the outer periphery of the region where the small holes are arranged is the print The printing apparatus is configured such that the area where the small holes are arranged is wider than the printing area so as to be located outside the printing area of the object, and the inside of the printing area is uniformly exposed to the vapor of the humidifying liquid. The region in which the small holes are arranged has a length in the moving direction longer than a length in the moving direction of the printing region, and a length in a direction perpendicular to the moving direction in the moving direction of the printing region. The printing apparatus according to claim 1, wherein the printing apparatus is longer than a length in a direction perpendicular to the direction. The steam generation device is disposed in a steam generation chamber capable of carrying the print object,
The steam generating chamber is the moisturizing liquid printing apparatus according to any one of claims 1 or claim 2, characterized in that it is configured to be filled with steam. The print head can print the coating liquid on the other part of the printing area in a state where the part where the coating liquid is printed on the tip of the printing area is exposed to the vapor of the humidifying liquid. The printing apparatus according to claim 1, wherein the printing apparatus is configured as described above. Printing apparatus according to any one of claims 1 to 4, characterized in that it has a head moving device for moving substantially in a vertical direction to the moving direction of the print head and the printing object. The printing apparatus according to claim 3, wherein a pump for discharging the gas in the steam generation chamber is connected to the steam generation chamber. The steam generation device includes a steam discharge section in which the steam discharge surface is disposed on one surface, and a heating unit that heats the steam discharge section,
Printing apparatus according to any one of claims 1 to 6 wherein the steam-emitting portion, characterized in that the droplets of the moisturizing liquid is configured to be supplied. The steam generation device includes a steam discharge portion in which the vapor discharge surface is disposed on one surface, and the vapor discharge portion is configured to be supplied with steam of the humidifying liquid. The printing apparatus according to any one of claims 1 to 6 . The printing apparatus according to claim 1, wherein the printing apparatus includes one or two or more steam generation apparatuses.

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