Film formation method, method for manufacturing electrode, method for manufacturing power storage device, power generation device or photovoltaic device, and film formation apparatus

Abstract

To improve the uniformity of a formed film.SOLUTION: A film formation method according to one embodiment of the invention is a film formation method for forming a film on a coating target, and comprises a coating step in which a liquid is discharged from each of a plurality of discharge heads provided along a conveyance direction of the coating target being conveyed, and is applied to the coating target. Each of the plurality of discharge heads has a plurality of liquid discharge nozzles arranged along a direction intersecting the conveyance direction. In the coating step, each of the plurality of discharge heads applies at least a first liquid, a second liquid, and a third liquid. The second liquid is applied at a position substantially equal to a position where the first liquid is applied along the width direction. The third liquid is applied at a position between the position where the first liquid is applied and the position where the second liquid is applied in the conveyance direction, and at a position different from the position where the first liquid is applied along the width direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a film forming method, an electrode manufacturing method, an electricity storage device, a power generation device or a solar power generation device manufacturing method, and a film forming apparatus. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a film forming method for forming a film on a substrate is known.

[0003] Also disclosed is a method of using a printhead for an inkjet printer that prints multiple pixels on a recording medium in a single pass using a complementary printing mode, the printhead having first and second nozzle arrays arranged within the printhead so that they are substantially parallel to each other and the nozzle positions in the printing process direction are aligned (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the method of Patent Document 1, when liquid is applied by using a plurality of ejection units such as print heads, there is room for improvement in the uniformity of the film that is formed.

[0005] An object of the present invention is to improve the uniformity of the film formed. [Means for solving the problem]

[0006] A film formation method according to one aspect of the present invention is a film formation method for forming a film on a workpiece, comprising a coating step of ejecting liquid from each of a plurality of ejection heads arranged along a transport direction of the workpiece being transported, and applying the liquid to the workpiece, wherein each of the plurality of ejection heads has a plurality of liquid ejection nozzles arranged along a direction intersecting the transport direction, and in the coating step, each of the plurality of ejection heads applies at least a first liquid, a second liquid, and a third liquid, wherein the second liquid is applied at a position along the width direction that is approximately equal to the position where the first liquid is applied, and the third liquid is applied at a position along the transport direction between the position where the first liquid is applied and the position where the second liquid is applied, but different from the position where the first liquid is applied along the width direction. [Effects of the Invention]

[0007] According to the present invention, the uniformity of the formed film can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of the configuration of a film forming apparatus according to an embodiment. [Figure 2] 1 is a diagram illustrating an example of the configuration of an inkjet head according to an embodiment. [Figure 3] FIG. 2 is a block diagram illustrating an example of a functional configuration of a control unit according to the embodiment. [Figure 4] 4 is a flowchart showing an example of the operation of the film forming apparatus according to the embodiment. [Figure 5] 3A to 3C are diagrams illustrating an example of ink application by the film forming method according to the first embodiment. [Figure 6] FIG. 10 is a diagram showing an example in which an even number of pixels are included between the first ink and the second ink. [Figure 7] 7(a) and 7(d) are diagrams showing the operation of the film forming method according to the first embodiment, in which FIG. 7(a) is a diagram of a comparative example, FIG. 7(b) is a diagram showing an application position error in FIG. 7(a), FIG. 7(c) is a diagram of this embodiment, and FIG. 7(d) is a diagram showing an application position error in FIG. 7(c). [Figure 8]10A to 10C are diagrams illustrating an example of ink application by a film forming method according to a second embodiment. [Figure 9] 10A to 10C are diagrams illustrating an example of ink application by a film forming method according to a third embodiment. [Figure 10] 10A to 10C are diagrams illustrating an example of ink application by a film forming method according to a fourth embodiment. [Figure 11] 10A to 10C are diagrams illustrating an example of ink application by a film forming method according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes the embodiments of the present invention with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals, and redundant explanations will be omitted where appropriate.

[0010] Furthermore, the embodiments shown below are intended to exemplify a film formation method and a film formation apparatus for embodying the technical concept of the present invention, and the present invention is not limited to the embodiments shown below. The dimensions, materials, shapes, relative positions, etc. of the components described below are intended to be illustrative, and are not intended to limit the scope of the present invention, unless otherwise specified. Furthermore, the sizes and positional relationships of the components shown in the drawings may be exaggerated for clarity of explanation.

[0011] The film formation method according to the embodiment forms a film on a substrate. The thickness of the film is not particularly limited, as long as it forms a layer on the substrate. Substrates include, for example, electrode substrates (current collectors) used in power storage devices such as batteries, power generation devices such as fuel cells, and solar power generation devices. The film formation method involves applying a liquid in which various materials, including powdered active materials and catalyst compositions, are dispersed to the substrate, followed by fixing and drying, thereby forming an electrode or the like having a film containing the various materials on the substrate.

[0012] Examples of methods for applying a liquid to a substrate to form a film include spraying, dispenser, die coater or lift coating, and printing using an inkjet head.

[0013] However, there is a trade-off between productivity and quality of the above devices, and increasing productivity to meet the demands of an expanding market can sometimes result in a decrease in electrode positioning accuracy or an increase in defects, resulting in a decrease in device quality.

[0014] For example, if defects that occur on the electrode surface, electrode end face, or electrode interface are left as they are and the product is shipped to the market, certain substances may accumulate at the defective area over time or due to vibration, or mechanical contact with the electrode interface may cause a short circuit or leakage, which may lead to fire or a shortened lifespan of the device.

[0015] In the embodiment, a process is performed in which a liquid is applied to the material to be coated by each of a plurality of discharge heads arranged along the transport direction of the material to be coated. Each of the plurality of discharge heads has a plurality of liquid discharge nozzles arranged along the width direction intersecting with the transport direction and for discharging the liquid.

[0016] In the coating process, each of the multiple ejection heads applies a first liquid, a second liquid, and a third liquid. The second liquid is applied at a position along the width direction that is approximately the same as the position where the first liquid is applied, and the third liquid is applied at a position along the transport direction that is between the positions where the first liquid is applied and the second liquid is applied, but is different from the position where the first liquid is applied along the width direction.

[0017] This allows for dispersion of the application position error even when multiple ejection heads apply liquid to the workpiece, thereby reducing gap areas where the liquid is not applied to the workpiece, thereby improving the uniformity of the film that is formed.

[0018] Here, "equal positions" means that the approximate centers of the liquid applied to the substrate are approximately equal. "Different positions" means that the approximate centers of the liquid applied to the substrate are different. "Application position error" means the error from the desired position where the ink ejected by the ejection head is applied to the substrate. "Different positions" means that the centers of the liquid are separate, so long as the liquids are partially overlapping.

[0019] The film forming method and film forming apparatus according to the embodiment will be described in detail below.

[0020] [Embodiment] <Configuration example of film forming apparatus 100> First, the configuration of a film forming apparatus 100 according to an embodiment will be described. Fig. 1 is a diagram illustrating an example of the configuration of the film forming apparatus 100. Fig. 1 shows the inside of the film forming apparatus 100 seen through from a direction substantially perpendicular to the conveyance direction 10 of a material 102 to be coated.

[0021] 1, the film forming apparatus 100 includes an unwinding section 101, an inkjet head 103, a platen 104, a heat drum 105, a hot air drying section 106, a conveying roller 107, a winding section 108, and a control section 400. These are arranged in this order from upstream to downstream along the conveying direction 10 of the material 102 to be coated.

[0022] The film forming device 100 applies ink ejected from an inkjet head 103 to the material 102 to be coated while transporting the material 102 by an unwinding unit 101 and a winding unit 108, thereby forming a uniform film of ink on the material 102. Each component will be described in detail below.

[0023] (unwinding means, winding means) In this embodiment, an unwinding unit 101 is used as the unwinding means for the material to be coated 102, and a winding unit 108 is used as the winding means for the material to be coated 102. The unwinding unit 101 supplies the material to be coated 102 to the conveying path of the film forming device 100 by rotating the material to be coated 102 stored in a roll form.

[0024] The winding section 108 winds up the material 102 on which the ink has been applied to form a film, and stores it in a roll.

[0025] (Transportation means) The platen 104 guides the material 102 to be coated so that it is transported along the transport path. In addition to the transport roller 107, transport rollers not indicated with a reference numeral are also used as transport means. The transport means, unwinding means, and winding means constitute the transport means for the material 102 to be coated.

[0026] Although this also applies to other processes, the coating speed in the film forming apparatus 100 is preferably 30 [m / min] to 100 [m / min], which makes it suitable for use in cases where high-speed film formation is required.

[0027] The material to be coated 102 is a substrate that is continuous along the conveying direction 10. The film forming device 100 conveys the material to be coated 102 along a conveying path between an unwinding section 101 and a winding section 108. The length of the material to be coated 102 along the conveying direction 10 is at least longer than the conveying path between the unwinding section 101 and the winding section 108. The film forming device 100 is configured to be able to continuously form a film on the material to be coated 102 that is continuous along the conveying direction 10.

[0028] (ink) The ink is composed of a liquid that realizes the function of a film and is an example of a liquid that is ejected from each of the multiple inkjet heads. There are no particular limitations on the ink, as long as it has a viscosity and surface tension that allows it to be ejected from the inkjet head, but it is preferable that the viscosity of the ink is 30 mPa s or less at room temperature and normal pressure, or when heated or cooled.

[0029] More specifically, these include solutions, suspensions, emulsions, etc. containing solvents such as water and organic solvents, electrode materials such as dyes, pigments, and active materials, functionality-imparting materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium, edible materials such as natural pigments, etc. These can be used, for example, in applications such as printing inks, surface treatment solutions, and liquids for forming components of electronic elements and light-emitting elements, and various devices such as electronic circuit resist patterns.

[0030] Furthermore, when the ink contains a large amount of non-volatile components or when ink containing metal oxide particles as the main component is used, it is particularly difficult to form a uniform film, and therefore this embodiment is particularly effective.

[0031] (Liquid application means) The liquid application means is a means for ejecting ink and applying the ink onto the material to be applied 102. As shown in Fig. 1, the film forming apparatus 100 is provided with an inkjet head 103 as the liquid application means.

[0032] The film forming apparatus 100 is provided with inkjet heads 103A, 103B, 103C, and 103D arranged along the transport direction 10 of the material to be coated 102. However, the present invention is not limited to this, and the film forming apparatus 100 may be provided with two or more inkjet heads arranged along the transport direction 10. Note that the inkjet heads 103A, 103B, 103C, and 103D have the same configuration, and inkjet head 103 is a general term used when there is no particular distinction between the inkjet heads 103A, 103B, 103C, and 103D.

[0033] The inkjet head 103 has a plurality of nozzle rows in which a plurality of nozzles are arranged along the width direction (a direction substantially perpendicular to the transport direction 10) of the material 102 to be coated. The film forming device 100 is provided with the inkjet head 103 so that the direction of ink ejection from the nozzles is directed toward the material 102 to be coated. The inkjet heads 103A, 103B, 103C, and 103D are examples of a plurality of ejection heads provided along the transport direction 10 of the material 102 to be coated being transported.

[0034] The inkjet head 103 is a line-type inkjet head. A "line-type inkjet head" is an inkjet head in which nozzles that eject ink are arranged across the entire width of the material 102. The width of the inkjet head 103 does not necessarily have to be the entire width of the material 102 and can be determined appropriately.

[0035] In industrial applications, the inkjet method using a line-type inkjet head, as shown in Figure 1, is preferred for high-speed film formation on large amounts of substrate. However, in industrial applications, film formation is required continuously for long periods of time, so when a line-type head is used, some nozzles may not eject ink for long periods of time, depending on the film shape. In these nozzles, ink components may become uneven due to drying of the ink in the nozzle or settling of particle components in the ink, resulting in ejection failure.

[0036] Therefore, in the ink application process, it is preferable to vibrate the ink interface in the nozzle or constantly circulate the ink in the ejection head in nozzles that do not eject ink. By vibrating the ink interface in the nozzle or constantly circulating the ink in the ejection head, the ink in the nozzle and the ink in the ink flow path of the inkjet head, such as a pressure chamber connected to the nozzle, can be made uniform, thereby suppressing non-uniformity of the ink in the nozzle. This further suppresses the occurrence of abnormal films due to ejection defects. The ink interface in the nozzle refers to the interface of the ink that comes into contact with the atmosphere or gas.

[0037] In the inkjet head 103, means for applying a stimulus to ink to cause it to be ejected can be appropriately selected depending on the purpose, and examples of such means include a pressure device, a piezoelectric element, a vibration generator, an ultrasonic oscillator, a light, etc. Specific examples include a piezoelectric actuator such as a piezoelectric element, a shape memory alloy actuator that uses a metal phase change due to a temperature change, and an electrostatic actuator that uses electrostatic force.

[0038] Among these, it is particularly preferable to use a method of applying a voltage to a piezoelectric element attached to a position called a pressure chamber (also called a liquid chamber, etc.) in an ink flow path inside the inkjet head 103. When a voltage is applied to this inkjet head 103, the piezoelectric element bends, and the volume of the pressure chamber decreases, thereby pressurizing the ink in the pressure chamber and ejecting the ink from the nozzle as droplets.

[0039] The inkjet head 103 includes an inkjet ejection unit, which is a collection of functional parts and mechanisms related to ink ejection from the inkjet head 103. The inkjet ejection unit includes a combination of the inkjet head 103 with at least one of a supply mechanism, a maintenance and recovery mechanism, and a liquid ejection head movement mechanism.

[0040] (material to be coated) A layer mainly composed of particles provided on an impermeable substrate such as a metal sheet can be used as the substrate 102. The layer mainly composed of particles provided on the impermeable substrate is, for example, a layer mainly composed of graphite.

[0041] The impermeable substrate includes metal sheets such as aluminum, aluminum oxide, copper, stainless steel, nickel, and platinum, and resin films such as polypropylene film, polyethylene terephthalate film, and nylon film.

[0042] (Drying means) The drying means is a means for drying the ink on the coating target material 102 after the ink has been ejected. In FIG. 1, the drying means 200 includes the heat drum 105 and the hot air drying unit 106.

[0043] The heat drum 105 is a rotatable drum. The heat drum 105 is an example of a temperature control member that heats or cools the material 102 to be coated by bringing the outer circumferential surface into contact with the material 102 to be coated and conveyed while ink is being applied thereto.

[0044] Methods of temperature adjustment using the heat drum 105 include a method of heating or cooling the material to be coated 102 using a liquid or gas filled inside the heat drum 105 as a heat exchange medium, or a method of providing a heat source device inside the heat drum 105. The drying means 200 uses the liquid or gas filled inside the heat drum 105 as a heat exchange medium and maintains the heat exchange medium at a predetermined temperature by circulating it between the heat drum 105 and an external device such as a chiller provided outside the heat drum 105. The drying means 200 heats or cools the material to be coated 102 by heat exchange with this heat exchange medium, adjusting the temperature to a predetermined level.

[0045] There are no particular restrictions on the liquid that flows inside the heat drum 105, as long as it is fluid, such as water or oil, but water is preferable because it is easy to handle. From the standpoint of cost and safety, it is preferable to use heated air as the gas that flows inside the heat drum 105.

[0046] The drying means 200 sucks liquid or gas circulating between the heat drum 105 and an external device such as a chiller into the heat drum 105 and discharges it to the outside through valves provided at both ends of the heat drum 105 (ends perpendicular to the conveying direction 10).

[0047] The method of providing a heat source device inside the heat drum 105 includes a halogen heater, an infrared heater, a nichrome heater, or the like.

[0048] The hot air drying unit 106 is provided opposite the outer peripheral surface of the heat drum 105 and includes a nozzle with an opening extending in the width direction. The hot air drying unit 106 heats the material 102 to dry the ink on the material 102 by blowing hot air from the nozzle onto the material 102 to be coated that is wrapped around the heat drum 105. Alternatively, instead of or in addition to the hot air drying unit 106, an infrared heater may be provided, and the surface of the material 102 to be coated may be irradiated with infrared rays to dry the ink on the material 102 to be coated.

[0049] When the temperature of the heat drum 105, the temperature of the hot air from the hot air drying section 106, and the wind speed of the hot air blown by the hot air drying section 106 are set within an appropriate range depending on the drying properties of the solvent used in the ink and the effect of damage to the coated material, the power consumption required for drying can be reduced.

[0050] (Control unit) The control unit 400 controls the operation of the film forming apparatus 100. The control unit 400 can be installed at any position inside or outside the film forming apparatus 100.

[0051] <Configuration example of inkjet head 103> Next, the configuration of the inkjet head 103 will be described with reference to Fig. 2. Fig. 2 is a diagram illustrating an example of the configuration of the inkjet head 103. Fig. 2 is a schematic enlarged view of inkjet heads 103A and 103B arranged along the transport direction 10, viewed from the ink ejection direction side.

[0052] 2, the inkjet head 103A has a nozzle plate 302A on which a plurality of nozzles 301 are formed, the nozzles 301 being arranged at a substantially constant nozzle interval d along the width direction 11. The plurality of nozzles 301 constitute two nozzle rows, nozzle rows 303A1 and 303A2. In the inkjet head 103A, the nozzle rows 303A1 and 303A2 are arranged so as to be offset from each other along the width direction 11 by a distance substantially half the nozzle interval d.

[0053] Similarly, inkjet head 103B has a nozzle plate 302B in which a plurality of nozzles 301 are formed and arranged at approximately regular intervals along the width direction 11. Two nozzle rows each including a plurality of nozzles 301 are formed in nozzle plate 302B. The plurality of nozzles 301 constitute two nozzle rows, nozzle rows 303B1 and 303B2. In inkjet head 103B, nozzle row 303B1 and nozzle row 303B2 are arranged so as to be offset from each other along the width direction 11 by a distance approximately half the nozzle spacing d.

[0054] In the film forming apparatus 100, the nozzle rows 303A1 and 303B1 are arranged at approximately equal positions in the width direction 11, and the nozzle rows 303A2 and 303B2 are arranged at approximately equal positions in the width direction 11.

[0055] 2 illustrates a configuration in which inkjet heads 103A and 103B each have two nozzle rows, but the number of nozzle rows is not limited to this. Inkjet heads 103A and 103B may each have one nozzle row or three or more nozzle rows. Also, while FIG. 2 illustrates only inkjet heads 103A and 103B of inkjet head 103, the same applies to inkjet heads 103C and 103D.

[0056] <Example of functional configuration of control unit 400> Next, the functional configuration of the control unit 400 will be described with reference to Fig. 3. Fig. 3 is a block diagram illustrating an example of the functional configuration of the control unit 400.

[0057] 3, the control unit 400 has a transport control unit 401 and a discharge control unit 402. These functions are realized by electric circuits, and some of these functions can also be realized by software (CPU: Central Processing Unit). These functions may also be realized by multiple circuits or multiple pieces of software.

[0058] The transport control unit 401 controls the start and stop of transport of the material to be coated 102 by the unwinding unit 101 and the winding unit 108, or the transport speed, etc. The ejection control unit 402 controls the timing of ejection of ink by the inkjet head 103.

[0059] <Operation Example of Film Forming Apparatus 100> Next, we will explain the operation of the film forming apparatus 100. When forming a film by the film forming apparatus 100, inkjet heads 103A, 103B, 103C, and 103D provided in the transport direction 10 sequentially eject the same type of ink to apply the ink onto the coating target material 102.

[0060] Fig. 4 is a flowchart showing an example of the operation of the film forming apparatus 100. Fig. 4 shows the operation starting from the point in time when a user operates the operation unit of the film forming apparatus 100 to start formation and the film forming apparatus 100 accepts the operation.

[0061] First, in step S41, the film forming apparatus 100 causes the unwinding section 101 to start unwinding the material to be coated 102, causes the winding section 108 to start winding the material to be coated 102, and starts conveying the material to be coated 102.

[0062] Next, in step S42, the inkjet head 103A ejects ink from all nozzles in parallel toward the transported material 102, and after the material 102 has been transported a predetermined distance, all nozzles stop ejecting ink. As a result, the inkjet head 103A applies ink to an area on the material 102 that corresponds to a predetermined distance in the transport direction 10 and the entire width in the width direction.

[0063] Next, in step S43, the film forming apparatus 100 determines whether to terminate film formation. The film forming apparatus 100 determines whether to terminate film formation by determining whether a predetermined termination condition is satisfied, or by determining whether the film forming apparatus 100 has received a termination operation from the user via the operation unit. This also applies to the termination determination described below.

[0064] If it is determined in step S43 that the film formation is to be ended (step S43, Yes), the operation proceeds to step S50. On the other hand, if it is determined that the film formation is not to be ended (step S43, No), the operation proceeds to step S44.

[0065] Next, in step S44, inkjet head 103B ejects ink from all nozzles in parallel toward the transported material 102, and stops ejecting ink from all nozzles after the material 102 has been transported a predetermined distance. As a result, inkjet head 103B applies ink to an area on the material 102 that corresponds to a predetermined distance in the transport direction 10 and to the entire width in the width direction, downstream in the transport direction 10 from the area where ink was applied by inkjet head 103A.

[0066] Inkjet head 103B applies ink to a position different from that of inkjet head 103A in the transport direction 10, so that the ink is applied intermittently, not continuously, onto the material 102. Inkjet head 103B applies ink without any gaps to the area where ink was applied by inkjet head 103A.

[0067] Furthermore, the inkjet head 103B applies ink onto the material 102 so that the area of ​​the region onto which the ink is applied by the inkjet head 103B is equal to the area of ​​the region onto which the ink is applied by the inkjet head 103A.

[0068] Subsequently, in step S45, the film forming apparatus 100 determines whether or not to end the film formation.

[0069] If it is determined in step S45 that the film formation is to be ended (step S45, Yes), the operation proceeds to step S50. On the other hand, if it is determined that the film formation is not to be ended (step S45, No), the operation proceeds to step S46.

[0070] Next, in step S46, inkjet head 103C ejects ink from all nozzles in parallel toward the transported material 102, and stops ejecting ink from all nozzles after the material 102 has been transported a predetermined distance. As a result, inkjet head 103C applies ink to an area on the material 102 that corresponds to a predetermined distance in the transport direction 10 and to the entire width in the width direction, downstream in the transport direction 10 from the area to which ink was applied by inkjet head 103B.

[0071] Inkjet head 103C applies ink to a position different from that of inkjet head 103B along the transport direction 10, so that the ink is applied intermittently, not continuously, onto the material to be coated 102. Inkjet head 103C applies ink without any gaps to the area where ink was applied by inkjet head 103B.

[0072] Furthermore, the inkjet head 103C applies ink onto the material 102 so that the area of ​​the region onto which the ink is applied by the inkjet head 103C is equal to the area of ​​the region onto which the ink is applied by the inkjet head 103B.

[0073] Subsequently, in step S47, the film forming apparatus 100 determines whether or not to end the film formation.

[0074] If it is determined in step S47 that the film formation is to be ended (step S47, Yes), the operation proceeds to step S50. On the other hand, if it is determined that the film formation is not to be ended (step S47, No), the operation proceeds to step S48.

[0075] Next, in step S48, the inkjet head 103D ejects ink from all nozzles in parallel toward the transported material 102, and stops ejecting ink from all nozzles after the material 102 has been transported a predetermined distance. As a result, the inkjet head 103D applies ink to an area on the material 102 that corresponds to a predetermined distance in the transport direction 10 and to the entire width in the width direction, downstream in the transport direction 10 from the area to which the inkjet head 103C applied ink.

[0076] Inkjet head 103D applies ink at a different position along transport direction 10 from inkjet head 103C, so that ink is applied intermittently, not continuously, onto material 102. Inkjet head 103D applies ink without gaps to the area where ink was applied by inkjet head 103C.

[0077] Furthermore, the inkjet head 103D applies ink onto the material 102 so that the area of ​​the region onto which the ink is applied by the inkjet head 103D is equal to the area of ​​the region onto which the ink is applied by the inkjet head 103C.

[0078] Subsequently, in step S49, the film forming apparatus 100 determines whether or not to end the film formation.

[0079] If it is determined in step S49 that the film formation is to be ended (step S49, Yes), the operation proceeds to step S50. On the other hand, if it is determined that the film formation is not to be ended (step S49, No), the operation returns to step S42, and the operations from step S42 onwards are performed again.

[0080] Subsequently, in step S50, the film forming apparatus 100 causes the unwinding section 101 to stop unwinding the material to be coated 102, causes the winding section 108 to stop winding the material to be coated 102, and stops conveying the material to be coated 102.

[0081] In this manner, the film forming apparatus 100 can apply ink onto the substrate 102 .

[0082] [First embodiment] <Example of ink application by the film forming method according to the first embodiment> Next, the application of ink to a coating target 102 by the film forming method according to the first embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram for explaining an example of ink application according to this embodiment, with Fig. 5(a) showing a comparative example and Fig. 5(b) showing this embodiment. The comparative example is an example to which this embodiment is not applied.

[0083] 5 also shows positions where ink ejected from inkjet head 103A and inkjet head 103B of inkjet head 103 is applied to substrate 102. Each square shown in FIG. 5 represents a pixel 51 where ink is applied one drop at a time on substrate 102. Multiple pixels 51 are arranged along both transport direction 10 and width direction 11, forming a matrix with transport direction 10 as columns and width direction 11 as rows. Note that pixel 51 is a collective term for multiple pixels. Also, while a square-shaped pixel 51 is shown as an example of pixel 51, the shape of pixel 51 is not limited to this and may be any shape.

[0084] The "A" shown in pixel 51 indicates that the pixel is coated with ink by inkjet head 103A, and the "B" shown in pixel 51 indicates that the pixel is coated with ink by inkjet head 103B. This also applies hereinafter.

[0085] 5(a), in the comparative example, in order from the downstream side (top side in the figure) along the transport direction 10, inkjet head 103A applies ink to the first row, inkjet head 103B applies ink to the second row, inkjet head 103A applies ink to the third row, and inkjet head 103B applies ink to the fourth row. Different inkjet heads apply ink to each row. The same applies to inkjet heads 103C and 103D.

[0086] In contrast to this, as shown in FIG. 5(b), in this embodiment, each of the inkjet heads 103A and 103B applies ink in a staggered pattern.

[0087] Applying ink in a staggered pattern will be described in more detail. As shown in Fig. 5(b), the inkjet head 103A applies a first ink 511, a second ink 512, and a third ink 513. Note that the first ink 511, the second ink 512, and the third ink 513 in Fig. 5(b) represent the inks applied to the pixels 51, respectively.

[0088] The second ink 512 is applied at the same position as the first ink 511 along the width direction 11. In other words, the pixels to which the second ink 512 is applied and the pixels to which the first ink 511 is applied have the same coordinates along the width direction 11.

[0089] The third ink 513 is applied at a position intermediate between the first ink 511 and the second ink 512 along the transport direction 10, and at a different position from the first ink 511 along the width direction 11. In other words, the pixel to which the third ink 513 is applied and the pixel intermediate between the first ink 511 and the second ink 512 along the transport direction 10 have the same coordinates along the transport direction 10. The pixel to which the third ink 513 is applied and the pixel to which the first ink 511 is applied have different coordinates along the width direction 11.

[0090] As explained above, "applying ink in a staggered pattern" means applying the first ink 511, the second ink 512, and the third ink 513. Here, the first ink 511 is an example of the first liquid, the second ink 512 is an example of the second liquid, and the third ink 513 is an example of the first liquid.

[0091] Although only the first ink 511, the second ink 512, and the third ink 513 have been described among the inks applied by the inkjet head 103A, the inkjet head 103A also applies inks other than the first ink 511, the second ink 512, and the third ink 513 in a staggered pattern to the material 102 to be coated.

[0092] Inkjet head 103B also applies ink in a staggered pattern to the material 102. However, as shown in Fig. 5(b), the ink is applied so that the pixels 51 do not overlap with the ink applied by inkjet head 103A. Inkjet heads 103C and 103D also apply ink in a staggered pattern to the material 102 so that the pixels 51 do not overlap with the other inkjet heads.

[0093] Furthermore, although an example has been shown in which the pixel to which the first ink 511 is applied and the pixel to which the third ink is applied are adjacent along the width direction 11, one or more pixels may be included between the two pixels along the width direction 11.

[0094] Furthermore, Figure 5(b) shows an example in which one pixel is interposed between the pixel to which the first ink 511 is applied along the transport direction 10 and the pixel to which the second ink 512 is applied, but this is not limited to this, and two or more pixels may be interposed between the two pixels.

[0095] Here, when an odd number of pixels are interposed between a pixel to be coated with the first ink 511 and a pixel to be coated with the second ink 512 along the transport direction 10, the third ink 513 is applied to a pixel interposed between the two pixels. In the example of Fig. 5(b), there is one pixel, which is an odd number, interposed between a pixel to be coated with the first ink 511 and a pixel to be coated with the second ink 512 along the transport direction 10, and the third ink 513 is applied to this pixel.

[0096] However, if there is an even number of pixels between a pixel to be coated with the first ink 511 and a pixel to be coated with the second ink 512 along the transport direction 10, there is no pixel whose center is located midway between the two pixels. In this case, the third ink 513 is applied to a pixel whose center is located 0.5 pixels upstream or downstream along the transport direction 10 from the midway between the two pixels.

[0097] Fig. 6 is a diagram showing a case where an even number of pixels are interposed between a pixel to be coated with a first ink 511 and a pixel to be coated with a second ink 512 along the transport direction 10. In the example of Fig. 6, an even number of pixels, that is, two pixels, are interposed between a pixel to be coated with the first ink 511 and a pixel to be coated with the second ink 512. A third ink 513 is applied to a pixel whose center is shifted 0.5 pixels downstream along the transport direction 10 from the midpoint M between the two pixels.

[0098] In other words, the third ink 513, which is applied midway between the first ink 511 and the second ink 512 along the transport direction 10, includes ink applied to a pixel centered at a position shifted 0.5 pixels upstream or downstream along the transport direction 10 from the midpoint M between the two pixels.

[0099] <Action of the Film Forming Method According to the First Embodiment> Next, the operation of the film forming method according to this embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram for explaining the operation according to this embodiment. Fig. 7(a) is a diagram showing ink applied to a coating target 102 according to a comparative example, and Fig. 7(b) is a diagram showing a case where an application position error occurs in Fig. 7(a). Figs. 7(a) and 7(b) correspond to ink applied to the position shown in Fig. 5(a).

[0100] 7 shows a case where an error in the coating position occurs along the transport direction 10. Since the inkjet heads 103A, 103B, 103C, and 103D are arranged at a distance from each other along the transport direction 10, such an error in the coating position along the transport direction 10 is likely to occur.

[0101] 7(c) is a diagram showing an example of ink applied to the application target material 102 according to this embodiment, and FIG. 7(d) is a diagram showing a case where an application position error occurs in FIG. 7(c). FIG. 7(c) and FIG. 7(d) correspond to ink applied to the position shown in FIG. 5(b).

[0102] 7, dots 61 shown with halftone hatching represent ink applied by inkjet head 103A to material 102. Dots 62 shown with diagonal hatching represent ink applied by inkjet head 103B to material 102.

[0103] When ideal application is performed without any application position error, there is no difference in the state of the ink applied to the material to be applied 102 between the comparative example shown in Figure 7(a) and the present embodiment shown in Figure 7(c), and there is no difference in the film formed on the material to be applied 102.

[0104] However, when an application position error occurs, in the comparative example, gap regions 63 where ink is not applied appear as streaks extending along the width direction 11, as shown in FIG. 7(b).

[0105] In contrast, in this embodiment, as shown in Fig. 7(d), the area of ​​the gap region 64 is smaller than that of the gap region 63. This is because applying ink in a staggered pattern on the substrate 102 distributes application position errors and reduces the gap region. By reducing the gap region 64, the thickness of the film formed on the substrate 102 becomes uniform.

[0106] For example, let us say that the dot spacing along each of the transport direction 10 and the width direction 11 corresponds to a resolution of 1200 dpi (dots per inch), and the diameter of each dot is 30 μm. If the ink applied by inkjet head 103B is misaligned by 15 μm along the transport direction 10 relative to the ink applied by inkjet head 103A, the ink coverage rate on the substrate 102 will be approximately 78% in the comparative example. In contrast, this is 97% in this embodiment. Thus, in this embodiment, even when an application position error occurs, the coverage rate can be maintained high compared to the comparative example, and gap regions can be reduced.

[0107] <Effects of the film forming method according to the first embodiment> Next, the effects of the film forming method according to this embodiment will be described.

[0108] As described above, in this embodiment, a process is performed in which ink (liquid) ejected from each of inkjet heads 103A, 103B, 103C and 103D (multiple ejection heads) arranged along the transport direction 10 of the transported material 102 to be coated is applied to the material 102.

[0109] Each of the inkjet heads 103A, 103B, 103C, and 103D has a plurality of nozzles 301 that are arranged along the width direction 11 and eject ink. In the coating step, each of the inkjet heads 103A, 103B, 103C, and 103D coats a first ink 511 (first liquid), a second ink 512 (second liquid), and a third ink 513 (third liquid).

[0110] The second ink 512 is applied at a position along the width direction 11 that is approximately the same as the position where the first ink 511 is applied, and the third ink 513 is applied at a position along the transport direction 10 that is between the position where the first ink 511 is applied and the position where the second ink 512 is applied, and is different from the position where the first ink 511 is applied along the width direction 11.

[0111] This allows the inkjet heads 103A, 103B, 103C, and 103D to distribute the coating position error and reduce gaps, even if the inkjet heads 103A, 103B, 103C, and 103D apply the liquid to the substrate, thereby improving the uniformity of the film formed.

[0112] For example, when defects in a film formed on the material to be coated 102 are detected and the detected results are repaired, the repair processing time can be shortened, the amount of ink used for repair can be reduced, and the film can be formed at low cost.

[0113] [Second embodiment] Next, a film forming method according to a second embodiment will be described. The film forming apparatus 100 can be applied to the film forming methods according to this embodiment and each of the following embodiments. Furthermore, the same components as those described in the above embodiment will be assigned the same part numbers, and duplicated descriptions will be omitted as appropriate. This also applies to each of the following embodiments.

[0114] In this embodiment, the liquid ejected by multiple ejection heads is applied in overlapping fashion to the same area on the workpiece, thereby increasing the amount of liquid applied within a specified area on the workpiece, and enabling the formation of a thick film.

[0115] 8 is a diagram illustrating an example of ink application by the film forming method according to the present embodiment. Fig. 8 shows a state in which, of the four inkjet heads 103A, 103B, 103C, and 103D, inkjet heads 103A and 103C apply ink within the same pixel 51 on the substrate 102, and inkjet heads 103B and 103D apply ink within the same pixel 51 on the substrate 102.

[0116] The "C" shown in pixel 51 indicates that the pixel is coated with ink by inkjet head 103C, and the "D" shown in pixel 51 indicates that the pixel is coated with ink by inkjet head 103D. This also applies hereinafter.

[0117] The inks ejected from the four inkjet heads 103A, 103B, 103C, and 103D are applied onto the material 102 in a staggered pattern.

[0118] In this embodiment, of the four inkjet heads 103A, 103B, 103C, and 103D, the inks ejected by the inkjet heads 103A and 103C are applied to the same area on the material to be coated 102 in an overlapping manner.

[0119] This makes it possible to increase the amount of ink applied to the substrate 102 and form a thicker film than when ink ejected from each of the four inkjet heads 103A, 103B, 103C, and 103D is applied onto the substrate 102 without overlapping. For example, in applications where an insulating layer that requires high insulation is to be formed on an electrode, this embodiment is particularly suitable because high insulation can be ensured by increasing the amount of ink applied and forming a thicker film.

[0120] The effects other than those described above are the same as those described in the first embodiment.

[0121] [Third embodiment] Next, a film forming method according to a third embodiment will be described.

[0122] In this embodiment, the multiple ejection heads include four or more ejection heads, including a first ejection head and a second ejection head adjacent to the first ejection head along the transport direction, and the liquid ejected by the first ejection head is applied at a position along the transport direction different from that of the liquid ejected by the second ejection head, thereby making the formed film uniform.

[0123] 9A and 9B are diagrams illustrating an example of ink application using the film forming method according to this embodiment. Fig. 9A shows the example, and Fig. 9B shows this embodiment. Note that this example is a case where none of the first to third embodiments is applied.

[0124] In FIG. 9, pixels indicated by halftone hatching indicate pixels onto which ink is applied by ejecting ink from either the inkjet head 103A or 103B.

[0125] 9(a), in the example, inkjet heads 103A and 103B apply ink to the same row, and inkjet heads 103C and 103D apply ink to the same row. The rows applied by inkjet heads 103A and 103B are different from the rows applied by inkjet heads 103C and 103D.

[0126] 9(b), in this embodiment, inkjet head 103A and inkjet head 103B apply ink to different rows, and inkjet head 103C and inkjet head 103D apply ink to different rows.

[0127] In other words, the inkjet head 103 has four or more ejection heads including the inkjet head 103A and the inkjet head 103B adjacent to the inkjet head 103A along the transport direction 10. The ink ejected by the inkjet head 103A is applied at a position along the transport direction 10 that is different from the position of the ink ejected by the inkjet head 103B.

[0128] The first ink 511, the second ink 512, and the third ink 513 are applied to the material 102 in a staggered pattern.

[0129] Here, the distance between inkjet head 103A and inkjet head 103B is shorter than the distance between inkjet head 103A and inkjet head 103C or 103D. Therefore, the coating position error of inkjet head 103B with respect to inkjet head 103A tends to be smaller than the coating position error of inkjet head 103C or 103D with respect to inkjet head 103A.

[0130] For example, when the entire film forming apparatus 100 thermally expands, the positions of inkjet heads 103B, 103C, and 103D relative to inkjet head 103A also shift as a result of the expansion. In this case, the amount of shift is proportional to the distance between the inkjet heads, so the amount of shift of inkjet head 103B is smaller than that of inkjet heads 103C and 103D.

[0131] This deviation directly results in an error in the coating position. Therefore, by having inkjet head 103A and inkjet head 103B apply ink at different positions along transport direction 10, the coating position error can be reduced, and the coating position error across all inkjet heads 103A, 103B, 103C, and 103D can be suppressed. This allows the formed film to be uniform.

[0132] The above-described effects are also obtained between inkjet head 103C and inkjet head 103D adjacent to inkjet head 103C in transport direction 10. Effects other than those described above are the same as those described in the first embodiment.

[0133] [Fourth embodiment] Next, a film forming method according to a fourth embodiment will be described.

[0134] In this embodiment, the multiple ejection heads include N ejection heads, and liquid ejected by M ejection heads adjacent to each other in the transport direction among the N ejection heads is applied to at least one pixel among all pixels arranged in the width direction, where N is an integer and M is an integer equal to or greater than N / 2 and less than N / 2+1.

[0135] The film forming apparatus 100 can also be applied to this embodiment, but here we will explain as an example a case where the film forming apparatus 100 has five inkjet heads 103A, 103B, 103C, 103D, and 103E arranged along the transport direction 10.

[0136] 10 is a diagram illustrating an example of ink application using the film forming method according to this embodiment. The letter "E" shown in a pixel 51 indicates that the pixel is coated with ink by inkjet head 103E. In addition, in FIG. 10, the pixels 51 coated with ink by inkjet heads 103A, 103B, and 103C are indicated by halftone hatching.

[0137] Here, inkjet heads 103A, 103B, 103C, 103D, and 103E are an example of N ejection heads. Therefore, N=5. Furthermore, inkjet heads 103A, 103B, and 103C are an example of M ejection heads that are adjacent to each other in the transport direction among the N ejection heads. Therefore, M=3.

[0138] As shown in FIG. 10, inkjet heads 103A, 103B, and 103C apply ink to at least one pixel out of all pixels arranged along width direction 11.

[0139] In the example shown in Fig. 10, the total number of pixels arranged along the width direction 11 is four. In the first row, starting from the downstream side (top in the figure) along the transport direction 10, the inkjet head 103A applies ink to two pixels, and in the second row, the inkjet head 103B applies ink to two pixels. In the third row, the inkjet heads 103A and 103C apply ink to four pixels. In this way, in each row, the inkjet heads 103A, 103B, and 103C apply ink to at least one pixel.

[0140] In this way, inkjet heads adjacent to each other in the transport direction 10 can apply ink at different positions in the transport direction 10. Therefore, as in the third embodiment, it is possible to suppress application position errors across the inkjet heads 103A, 103B, 103C, 103D, and 103E, and to form uniform films. Other effects are the same as in the first embodiment.

[0141] In this embodiment, the case of N=5 and M=3 is exemplified, but this is not limited to this and can be changed as appropriate within the range of conditions that N is an integer and M is an integer greater than or equal to N / 2 and less than N / 2+1.

[0142] [Fifth embodiment] Next, a film forming method according to a fifth embodiment will be described.

[0143] By leaving some of the pixels to which ink is to be applied uncoated, it is possible to reduce the amount of ink to be applied to the coating target material 102 and form a thin film. Here, "uncoated" means that no ink is applied.

[0144] However, if pixels to be left uncoated are concentrated locally, the thickness of the film in the concentrated areas will be thin, which may reduce the uniformity of the film.

[0145] Therefore, in this embodiment, the multiple ejection heads are capable of applying liquid to each of the multiple pixels, and in the application process, at least one of the first to third liquids is not applied, and the pixels corresponding to the liquid that is not applied are separated by one or more pixels.

[0146] FIG. 11 is a diagram illustrating an example of ink application using the film formation method according to this embodiment. A first ink 511 corresponds to the first liquid, and a second ink 512 corresponds to the second liquid. A non-coated pixel 514 is a pixel to which a third ink corresponding to a third liquid should be applied, but because the third ink is not applied, no ink is applied. The non-coated pixel 514 is a collective term for a plurality of non-coated pixels. In FIG. 11, the non-coated pixel 514 is indicated by halftone hatching.

[0147] As shown in Figure 11, four non-coated pixels 514 are separated by one pixel. This disperses the non-coated pixels 514, preventing localized concentration of non-coated pixels. As a result, it is possible to prevent a decrease in film uniformity. Furthermore, in the case of an insulating layer formed on an electrode as an example of a film, increasing the film uniformity can reduce the risk of short circuits.

[0148] 11 illustrates a case where one pixel is sandwiched between the non-coated pixels 514, but the present invention is not limited to this and may have one or more pixels. For example, when there are few non-coated pixels 514, more pixels may be sandwiched between the non-coated pixels 514. Furthermore, effects other than those described above are the same as those shown in the first embodiment.

[0149] Although the embodiments have been described above, the present invention is not limited to the specifically disclosed above embodiments, and various modifications and changes are possible without departing from the scope of the claims.

[0150] In the above-described embodiment, a configuration in which a uniform film is formed on a substrate is exemplified, but a predetermined pattern can also be formed on the substrate by ejecting ink from an inkjet head. This pattern includes, for example, an identification code such as a barcode or two-dimensional code that indicates information about the substrate or the electrodes to be manufactured by applying ink to the substrate. This allows information about the substrate to be formed or the electrodes to be manufactured to be efficiently added without performing a separate process.

[0151] Furthermore, all ordinal numbers, quantitative numbers, and other figures used in the description of the embodiments are merely examples for specifically explaining the technology of the present invention, and the present invention is not limited to the exemplified figures. Furthermore, the connection relationships between the components are merely examples for specifically explaining the technology of the present invention, and the connection relationships for realizing the functions of the present invention are not limited to these.

[0152] Furthermore, each function of the above-described embodiments can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to perform each function by software, such as a processor implemented by an electronic circuit, as well as devices such as an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or a conventional circuit module designed to perform each function described above. [Explanation of symbols]

[0153] 10 Conveying direction 11 Width direction 51 pixels 511 First ink (an example of the first liquid) 512 Second ink (an example of the second liquid) 513 Third ink (an example of a third liquid) 514 Uncoated pixels 100 Film forming equipment 101 Unwinding section 102 Material to be coated 103 Inkjet head 104 Platen 105 Heat Drum 106 Warm air drying section 107 Conveyor roller 108 Winding section 400 control section 401 Transport control unit 402 Discharge control section d Nozzle spacing M intermediate position [Prior art documents] [Patent documents]

[0154] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-130922

Claims

1. A film forming method for forming a film on a transported electrode, comprising: a coating step of discharging a liquid from at least a first discharge head and a second discharge head provided along a transport direction of the electrode and coating the liquid on the electrode; each of the first ejection head and the second ejection head has a plurality of nozzles aligned along a width direction that is a direction intersecting the transport direction; the first ejection head has a first nozzle and a third nozzle that is disposed at a position different from the first nozzle in the width direction; the second ejection head has a second nozzle; In the application step, the liquids ejected from the first ejection head and the second ejection head are applied to different positions on the electrode along the transport direction, The first nozzle comprises: a first region of the electrode; The liquid is applied to a second region of the electrode, the second region being spaced apart from the first region in the transport direction; the second nozzle applies the solution to a third region of the electrode, the third region being located between the first region and the second region; a third nozzle applying a coating to a fourth region of the electrode, the fourth region being located at a position different from the first region and the second region in the width direction and between the first region and the second region in the transport direction.

2. the second nozzle applies the solution to a fifth region of the electrode, the fifth region being spaced apart from the third region in the transport direction, and the second region being located between the fifth region and the third region; 2. The film forming method according to claim 1, wherein a fourth nozzle of the second ejection head applies the coating to a sixth region of the electrode, the sixth region being located at a position different from the third region and the fifth region in the width direction and between the third region and the fifth region in the transport direction.

3. The film forming method according to claim 1 , wherein the second nozzle is located at a position substantially equal to that of the first nozzle in the width direction.

4. The film forming method according to claim 1 , wherein the third region is located between the first region and the second region in the transport direction.

5. The film forming method according to claim 2 , wherein the fourth nozzle is located at a position substantially equal to that of the third nozzle in the width direction.

6. The film forming method according to claim 1 , wherein the type of the liquid ejected from the first ejection head and the type of the liquid ejected from the second ejection head are the same.

7. The film forming method according to claim 1 , wherein a functional layer is formed on the electrode by the liquid ejected from each of the first ejection head and the second ejection head.

8. The film forming method according to claim 7 , wherein the functional layer is an insulating layer.

9. The film forming method according to claim 1 , wherein the plurality of nozzles includes at least two nozzle rows offset from one another along the width direction.

10. The film forming method according to claim 1 , wherein each of the plurality of nozzles is arranged at a constant nozzle interval along the width direction and includes at least two nozzle rows that are offset by a distance of half the nozzle interval along the width direction.

11. A method for producing an electrode having a film, comprising the film formation method according to claim 1.

12. A method for manufacturing an electricity storage device, a power generation device, or a solar power generation device, comprising the method for manufacturing an electrode according to claim 11.

13. a conveying means for conveying the electrode; a liquid application means for discharging a liquid onto the electrode being transported and applying the liquid to the electrode; a control unit that controls the liquid application means to discharge the liquid onto the electrode, the liquid applying means includes at least a first ejection head and a second ejection head; each of the first ejection head and the second ejection head has a plurality of nozzles arranged along a width direction that is a direction intersecting a transport direction of the electrode; the first ejection head has a first nozzle and a third nozzle that is disposed at a position different from the first nozzle in the width direction; the second ejection head has a second nozzle; When the liquid applying means applies the liquid to the electrode, the control unit the liquid ejected from the first ejection head and the liquid ejected from the second ejection head are applied to different positions of the electrode along the transport direction; The first nozzle comprises: a first region of the electrode; The liquid is applied to a second region of the electrode, the second region being spaced apart from the first region in the transport direction; the second nozzle applies the solution to a third region of the electrode, the third region being located between the first region and the second region; The film forming device controls the third nozzle to apply the liquid to a fourth region of the electrode, the fourth region being located at a position different from the first region and the second region in the width direction and between the first region and the second region in the transport direction.

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