Droplet discharge head, head unit, and droplet discharge device

Abstract

To effectively suppress displacement of a droplet landing position in a nozzle array direction.SOLUTION: A droplet discharge head includes a plurality of nozzles 30 that discharge a droplet 10 to a sheet. When a direction X in which the plurality of nozzles 30 are arrayed is defined as a first direction and a relative movement direction Y in which the sheet and the nozzle 30 relatively move during droplet discharging is defined as a second direction, at least one gas blow port 70 that blows gas 8 is provided between the plurality of nozzles 30 arrayed in the first direction in the droplet discharge head in which the first direction and the second direction cross with each other.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a droplet ejection head, a head unit, and a droplet ejection device. [Background technology]

[0002] 2. Description of the Related Art A droplet ejection head mounted on an inkjet image forming apparatus or the like is known to have a plurality of nozzles arranged in a direction intersecting the sheet transport direction.

[0003] In such droplet ejection heads, there is a problem in that the landing position of the droplets is shifted in the direction of the nozzle arrangement due to the air currents that are generated when droplets are ejected from the nozzles. In particular, in droplet ejection heads in which multiple nozzles are arranged at high density and the ejected droplets are becoming smaller in response to higher image quality, miniaturization, and higher productivity, there is a tendency for the landing position of the droplets to be shifted in the direction of the nozzle arrangement due to the air currents that are generated when the droplets are ejected to be shifted significantly.

[0004] For example, Patent Document 1 (JP 2016-175243 A) proposes a droplet ejection head equipped with gas outlets arranged on either side of the ejection port along the relative movement direction between the medium and the ejection port, in order to suppress adhesion of mist to the droplet ejection surface of the ejection head while allowing droplets to be ejected at the desired position. Summary of the Invention [Problem to be solved by the invention]

[0005] However, Patent Document 1 does not consider a method for effectively suppressing deviation of the landing position of ejected droplets relative to the nozzle arrangement caused by air currents.

[0006] Therefore, an object of the present invention is to effectively suppress deviation of the droplet landing positions in the nozzle arrangement direction. [Means for solving the problem]

[0007] In order to solve the above problem, the present invention provides a droplet ejection head that has a plurality of nozzles that eject droplets onto a sheet, where the direction in which the plurality of nozzles are aligned is defined as a first direction and the direction in which the sheet and the nozzles move relative to each other during droplet ejection is defined as a second direction, and the first direction and the second direction intersect with each other, and the droplet ejection head is characterized in that the droplet ejection head has at least one gas outlet that ejects gas between the plurality of nozzles that are aligned in the first direction. [Effects of the Invention]

[0008] According to the present invention, it is possible to effectively prevent the droplet landing positions from shifting in the nozzle arrangement direction (first direction). [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating the configuration of an image forming apparatus according to a first embodiment of the present invention. [Figure 2] 1 is a block diagram showing a control system of an image forming apparatus according to a first embodiment of the present invention. [Figure 3] 1 is an exploded perspective view of a droplet ejection head according to a first embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view in the short side direction of the droplet ejection head shown in FIG. [Figure 5] FIG. 1 is a plan view showing the configuration of a head unit according to a first embodiment of the present invention. [Figure 6] 1 is a plan view of a nozzle surface of a droplet ejection head according to a first embodiment of the present invention, viewed from a direction perpendicular to the nozzle surface. [Figure 7] 1 is a schematic diagram illustrating the configuration of a gas supply mechanism provided in a droplet ejection head according to a first embodiment of the present invention. [Figure 8] 7 is a cross-sectional view taken along line AA in FIG. 6 showing how gas is blown out from a gas outlet in the first embodiment of the present invention. FIG. [Figure 9] 7 is a cross-sectional view taken along line BB in FIG. 6 showing how gas is blown out from a gas outlet in the first embodiment of the present invention. FIG. [Figure 10]10 is a cross-sectional view taken along the sheet conveying direction, showing how gas is blown out from a gas outlet in a second embodiment of the present invention. FIG. [Figure 11] FIG. 1 is a plan view showing an example of a serial type head unit. [Figure 12] FIG. 10 is a cross-sectional view showing a gas outlet provided in a serial type head unit. [Figure 13] FIG. 10 is a diagram showing the flow of gas when the droplet ejection head moves in one direction. [Figure 14] 10A and 10B are diagrams illustrating the gas flow when the droplet ejection head moves in the opposite direction. [Figure 15] FIG. 10 is a plan view showing an example in which nozzles are arranged in both the sheet conveying direction and a direction intersecting the sheet conveying direction. [Figure 16] 1 is a schematic diagram illustrating an example of an electrode manufacturing apparatus according to an embodiment of the present invention. [Figure 17] 10A and 10B are diagrams illustrating the air flow when droplets are ejected onto a sheet from one nozzle of a droplet ejection head. [Figure 18] FIG. 10 is a diagram showing the air flow when droplets are continuously ejected from one nozzle. [Figure 19] 10A and 10B are diagrams illustrating the air flow when droplets are continuously ejected from the nozzles in a case where a plurality of nozzles are arranged in one direction. [Figure 20] 10A and 10B are diagrams illustrating air flows when droplets are ejected as viewed from the nozzle arrangement direction. [Figure 21] FIG. 10 is a diagram showing how an airflow is generated in an area inside a nozzle row. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described below with reference to the accompanying drawings. In each drawing for explaining the present invention, components such as members and components having the same function or shape are designated by the same reference numerals as far as they can be distinguished, and once they have been described, their description will be omitted.

[0011] <Overall configuration of image forming apparatus> First, the overall configuration of an inkjet image forming apparatus, which is an example of a droplet ejection apparatus, will be described with reference to FIGS.

[0012] Fig. 1 is a schematic diagram of an image forming apparatus according to a first embodiment of the present invention, and Fig. 2 is a block diagram showing a control system of the image forming apparatus according to the first embodiment of the present invention.

[0013] 1, the image forming apparatus 100 according to the first embodiment of the present invention includes a sheet supply unit 1 that supplies a sheet S for image formation, an image forming unit 2 that forms an image on the sheet S, a conveying unit 3 that conveys the sheet S to the image forming unit 2, a drying unit 4 that dries the sheet S, and a sheet recovery unit 5 that recovers the sheet S on which the image has been formed. Also, as shown in FIG. 2, the image forming apparatus 100 according to the first embodiment of the present invention includes a control unit 6 that controls the sheet supply unit 1, the image forming unit 2, the conveying unit 3, the drying unit 4, and the sheet recovery unit 5.

[0014] The sheet supply unit 1 is provided with a supply roller 11 around which a long sheet S is wound in a roll, and a tension adjustment mechanism 12 that adjusts the tension applied to the sheet S. The supply roller 11 is configured to be rotatable in the direction of the arrow in FIG. 1, and the sheet S is unwound by the rotation of the supply roller 11. The tension adjustment mechanism 12 has multiple rollers across which the sheet S is stretched and which apply tension. The tension of the sheet S is adjusted by moving some of these rollers, and the sheet S is unwound from the supply roller 11 with a constant tension.

[0015] The image forming unit 2 is provided with a head unit 13 having a plurality of droplet ejection heads that eject droplets of ink or the like onto the sheet S, and a platen 14 as a sheet support member that supports the sheet S being transported. An image is formed on the sheet S by ejecting droplets from each droplet ejection head onto the sheet S based on image data generated by the control unit 6. The platen 14 is disposed opposite the head unit 13, and supports the lower surface of the sheet S supplied from the sheet supply unit 1. The platen 14 is also configured to be able to move towards and away from the head unit 13 so that the distance between the head unit 13 and the sheet S can be kept constant.

[0016] The conveying unit 3 is provided with a plurality of conveying rollers 15. With the sheet S stretched between the conveying rollers 15, the conveying rollers 15 rotate, thereby conveying the sheet S to the image forming unit 2. Note that the conveying unit 3 may include other conveying means such as a conveying belt.

[0017] The drying unit 4 is provided with a heating drum 16 that heats the sheet S. The heating drum 16 is a cylindrical member that rotates with the sheet S wrapped around its outer circumferential surface, and has a heat source such as a halogen heater disposed inside. When the sheet S, to which droplets have been applied in the image forming unit 2, is transported while being wrapped around the heating drum 16, the sheet S is heated, accelerating the drying of the sheet S. The heating means for heating the sheet S may be a contact-type heating means such as the heating drum 16, or a non-contact heating means such as a hot air generator that blows hot air onto the sheet S.

[0018] The sheet collection unit 5 is provided with a collection roller 17 that winds up and collects the sheet S, and a tension adjustment mechanism 18 that adjusts the tension applied to the sheet S. The collection roller 17 is configured to be rotatable in the direction of the arrow in FIG. 1, and as the collection roller 17 rotates, the sheet S is wound up into a roll and collected. The tension adjustment mechanism 18 has multiple rollers, similar to the tension adjustment mechanism 12 of the sheet supply unit 1. As some of these rollers move, the tension of the sheet S is adjusted, and the sheet S is wound up by the collection roller 17 at a constant tension.

[0019] The control unit 6 is configured by an information processing device such as a PC (Personal Computer). The control unit 6 generates image data to be formed on the sheet S, and also controls various operations of the sheet supply unit 1, image forming unit 2, conveyance unit 3, drying unit 4, and sheet collection unit 5. For example, the control unit 6 controls the rotation speeds of the supply roller 11, collection roller 17, and each conveyance roller 15, as well as the temperature of the heat source that heats the heating drum 16.

[0020] <Configuration of droplet ejection head> Next, the configuration of the droplet ejection head according to the first embodiment of the present invention will be described with reference to FIGS.

[0021] Fig. 3 is an exploded perspective view of the droplet ejection head according to the first embodiment of the present invention, and Fig. 4 is a cross-sectional view in the width direction of the droplet ejection head shown in Fig. 3.

[0022] As shown in FIG. 3, the droplet ejection head 20 according to the first embodiment of the present invention comprises a plurality of head bodies 21, a base member 22, a cover member 23, a heat dissipation member 24, a manifold 25, a printed circuit board (PCB) 26, and a module case 27.

[0023] The head bodies 21 are held by a base member 22, which serves as a holding member. To attach the head bodies 21 to the base member 22, first, the head bodies 21 are inserted into openings 22c (see FIG. 4) provided in the base member 22. Next, the head bodies 21 are joined to a cover member 23 joined to the base member 22. The cover member 23 has holes 23a (see FIG. 3) formed therein corresponding to the head bodies 21, and the peripheral edge of the head bodies 21 is joined to the edges of the holes 23a. The head bodies 21 are then fixed to the base member 22 by being fastened to the base member 22 with screws. More specifically, flange portions of a common flow path member 35 (see FIG. 4) are provided on the front and back sides of the head bodies 21 in the longitudinal direction (the direction perpendicular to the plane of the paper in FIG. 4), and these flange portions are fastened to the base member 22 with screws. In this way, the common flow path member 35 is held by the base member 22, and the head bodies 21 are fixed. The attachment structure of the head body 21 and the base member 22 is not limited to this, and the head body 21 may be attached by adhesive, caulking, or the like.

[0024] As shown in Figure 4, the head main body 21 includes a nozzle plate 31 on which nozzles 30 are provided, a flow path substrate 32 on which individual liquid chambers 41 communicating with the nozzles 30 are formed, a vibration plate 33 including a piezoelectric element 40, a holding substrate 34 laminated on the vibration plate 33, and a common flow path member 35 as a frame member laminated on the holding substrate 34.

[0025] In addition to the individual liquid chambers 41, the flow path substrate 32 is formed with supply-side individual flow paths 42 that communicate with the individual liquid chambers 41, and recovery-side individual flow paths 43 that communicate with the individual liquid chambers 41. The holding substrate 34 is formed with supply-side intermediate individual flow paths 44 that communicate with the supply-side individual flow paths 42 via openings 33a of the vibration plate 33, and recovery-side intermediate individual flow paths 45 that communicate with the recovery-side individual flow paths 43 via another opening 33b of the vibration plate 33.

[0026] A supply-side common flow path 46 communicating with the supply-side intermediate individual flow path 44 and a recovery-side common flow path 47 communicating with the recovery-side intermediate individual flow path 45 are formed in the common flow path member (frame member) 35. The supply-side common flow path 46 communicates with a supply port 48 via a flow path 51 of the manifold 25. On the other hand, the recovery-side common flow path 47 communicates with a recovery port 49 via another flow path 52 of the manifold 25.

[0027] The printed circuit board 26 and the piezoelectric element 40 of the head main body 21 are connected via a flexible wiring member 50. In addition, a driver IC (drive circuit) 53 is mounted on the flexible wiring member 50.

[0028] The base member 22 is preferably made of a material with a low linear expansion coefficient. Examples of materials with a low linear expansion coefficient include 42 alloy (iron alloy) with added nickel, and invar. When the base member 22 is made of such a material, even if the temperature of the base member 22 rises due to heat generation from the droplet ejection head 20, the amount of expansion of the base member 22 is small, making it less likely for the nozzles to shift position, and thus suppressing deviation of the ink ejection position. Furthermore, by making the nozzle plate 31 and the diaphragm 33 from a silicon single crystal substrate and making their linear expansion coefficients approximately the same as that of the base member 22, it is possible to further reduce nozzle position deviation due to thermal expansion.

[0029] FIG. 5 is a plan view showing the configuration of the head unit 13 according to the first embodiment of the present invention.

[0030] 5, the head unit 13 according to the first embodiment of the present invention includes two droplet ejection heads 20. When viewed from a direction perpendicular to the nozzle surface 31a having the nozzles 30, each droplet ejection head 20 is arranged so that its short side faces the sheet transport direction Y and its long side faces the direction X perpendicular to the sheet transport direction Y. Furthermore, the nozzles 30 are arranged in a row in the longitudinal direction of the droplet ejection head 20, i.e., in the direction X perpendicular to the sheet transport direction Y.

[0031] The head unit 13 according to the first embodiment of the present invention is a so-called line-type head unit. In this case, when the sheet S is transported in the direction of arrow Y in Fig. 5 and the sheet S reaches an image forming position facing the head unit 13, droplets are ejected from the head unit 13. At this time, the head unit 13 does not move relative to the transported sheet S, and droplets are ejected from the nozzles 30 of each head main body 21, thereby forming an image on the sheet S.

[0032] <The issue of misaligned droplet landing positions> However, in an image forming apparatus equipped with a head unit that ejects droplets, there is a problem in that when droplets are ejected from the nozzles, the landing position of the droplets may be shifted due to air currents that are generated by the ejection of the droplets. The mechanism of the landing position shift when droplets are ejected will be explained in detail below.

[0033] First, the mechanism by which an airflow is generated by droplet ejection will be described.

[0034] 17 is a diagram showing the air flow (air current 9) when a droplet 10 is ejected onto a sheet S from one nozzle 300 of the droplet ejection head 200. In FIG. 17, the white arrow indicates the ejection direction of the droplet 10, and the black arrow indicates the direction of the air flow (air current 9).

[0035] As shown in FIG. 17, when one droplet 10 is ejected from the nozzle 300, the droplet 10 slows down due to air resistance. At this time, as the momentum of the droplet 10 decreases, the momentum of the air increases by the amount corresponding to the decrease in the momentum of the droplet 10. This causes the air to move in the ejection direction of the droplet 10. As a result, the amount of air decreases near the nozzle 300, and in order to compensate for the decrease in the amount of air, an airflow 9 is generated near the nozzle 300 from the surrounding area toward the nozzle 300. Furthermore, on the sheet S side, air moves due to the ejection of the droplet 10, and the amount of air increases in the opposite direction from the nozzle 300 side, and in order to reduce this increase, an airflow 9 is generated in a direction away from the landing position of the droplet 10.

[0036] FIG. 18 is a diagram showing the air flow (air flow 9) when droplets 10 are continuously ejected from one nozzle 300. As shown in FIG.

[0037] 18, when droplets 10 are continuously ejected from the nozzle 300, the airflow 9 is continuously generated by the above mechanism. Then, when the ejection of droplets 10 continues for a certain period of time, the airflow 9 on the nozzle 300 side and the airflow 9 on the sheet S side join together, generating a circulating airflow 9.

[0038] FIG. 19 is a diagram showing the air flow (air flow 9) when droplets 10 are continuously ejected from each nozzle 300 in a case where a plurality of nozzles 300 are arranged in one direction (the direction of arrow X).

[0039] As shown in Figure 19, when droplets 10 are continuously ejected from multiple nozzles 300, airflows 9, indicated by dashed arrows in the figure, are generated near each nozzle 300 and on the sheet 300 side. Here, the airflows 9 generated between adjacent nozzles 300 are canceled out by the adjacent airflows 9, so almost no airflows 9 that affect the landing position of droplets 10 are generated in the inner region of the nozzle row. In contrast, at both ends of the nozzle row, there are no nozzles 300 further outward, so the adjacent airflows 9 do not cancel out each other, and airflows 9, indicated by solid arrows in the figure, are generated. That is, at both ends of the nozzle row, airflows 9 (9A) are generated that flow from the outside to the inside of the nozzle row relative to the nozzles 30 at both ends, and airflows 9 (9B) are generated that flow from both ends of the nozzle row to the outside on the sheet S side. Therefore, at both ends of the nozzle row, the droplets 10 are affected by the air currents 9 (9A, 9B), causing deviations in the landing positions of the droplets in the nozzle arrangement direction X.

[0040] FIG. 20 is a diagram showing the air flow (air flow 9) when droplets 10 are ejected as viewed from the nozzle arrangement direction (X direction).

[0041] As shown in FIG. 20 , when the sheet S is transported in a direction perpendicular to the nozzle arrangement direction X (the direction of the arrow Y), an airflow 9 (9C) is generated in the sheet transport direction Y perpendicular to the nozzle arrangement direction X as the sheet S is transported. Therefore, upstream of the nozzles 300 in the sheet transport direction Y, the airflow 9 (9B) on the sheet S side, which is generated as the droplets 10 are ejected, collides with the airflow 9 (9C) in the sheet transport direction Y. A portion of the airflow generated by this collision is returned toward the droplets 10 by the airflow (9C) in the sheet transport direction Y. As a result, as shown in FIG. 21 , an airflow 9 (9D) in the nozzle arrangement direction X may be generated in an area inside the nozzle array. Note that the generation of such an airflow 9 (9D) in an area inside the nozzle array is not limited to when the nozzle arrangement direction X and the sheet transport direction Y are perpendicular to each other, but may also occur when they intersect in a manner other than perpendicular.

[0042] Furthermore, during the droplet ejection operation, droplets 10 are not necessarily ejected from all nozzles 300, and therefore, if droplets 10 are not ejected from some nozzles 300, an airflow 9 (9D) similar to that shown in Figure 21 may occur. That is, if there are nozzles 300 in the nozzle row that do not eject droplets 10, the airflows 9 of adjacent nozzles 300 do not cancel each other out, and the same situation occurs in the inner region of the nozzle row as on both ends, and an airflow 9 (9D) may occur in the nozzle arrangement direction X.

[0043] As described above, in a configuration in which multiple nozzles 300 are arranged in a direction X perpendicular to or intersecting the sheet conveying direction Y, when droplets 10 are ejected from the nozzles 300 onto the sheet S, airflows 9 (9A, 9B) are generated in the nozzle arrangement direction X at least on both ends of the nozzle array, and in some cases, an airflow 9 (9D) in the nozzle arrangement direction X is also generated in an inner region of the nozzle array. As a result, the ejected droplets 10 are affected by the airflows 9 (9A, 9B, 9D) in the nozzle arrangement direction X, causing the landing positions of the droplets 10 to shift in the nozzle arrangement direction X. Furthermore, depending on the ejection conditions for each image to be formed, the combination of nozzles 300 that eject (or do not eject) droplets 10 and the amount of droplets 10 ejected also change, and therefore the airflows 9 generated as the droplets 10 are ejected also change. As a result, the landing positions of the droplets 10 that are affected by the airflows 9 also vary.

[0044] Therefore, in the present invention, the following droplet ejection head is proposed to effectively suppress deviation of droplet landing positions in the nozzle arrangement direction. Below, the characteristic features of the present invention will be described using a first embodiment of the present invention as an example.

[0045] <Characteristics of the present invention> FIG. 6 is a plan view of the nozzle surface 31a of the droplet ejection head 20 according to the first embodiment of the present invention, viewed from a direction perpendicular to the nozzle surface 31a.

[0046] 6, in the droplet ejection head 20 according to the first embodiment of the present invention, a plurality of nozzles 30 are arranged in a direction X that intersects with the sheet transport direction Y. Here, the nozzle arrangement direction X in which the plurality of nozzles 30 are arranged is defined as a "first direction," and the relative movement direction Y in which the sheet S and the nozzles 30 move relative to each other during droplet ejection is defined as a "second direction." In this case, the "first direction" and the "second direction" are perpendicular to each other. Note that in this case, the relative movement direction Y between the sheet S and the nozzles 30 during droplet ejection refers to the sheet transport direction Y in which the sheet S is transported.

[0047] Furthermore, in the droplet ejection head 20 according to the first embodiment of the present invention, gas outlets 70 for blowing out gas are arranged between the multiple nozzles 30 aligned in the nozzle arrangement direction X (first direction) and at positions outside the nozzles 30 at both ends that are positioned at the outermost sides in the nozzle arrangement direction X.

[0048] FIG. 7 is a schematic diagram showing the configuration of a gas supply mechanism provided in the droplet ejection head 20 according to the first embodiment of the present invention.

[0049] As shown in FIG. 7 , the gas supply mechanism 71 includes a gas supply unit 72 that supplies gas and a supply pipe 74 that connects a gas supply port 73 provided in the droplet discharge head 20 to the gas supply unit 72. The gas supply port 73 is connected to a plurality of gas outlets 70 provided in the droplet discharge head 20. Therefore, when gas is supplied from the gas supply unit 72 to the droplet discharge head 20 via the supply pipe 74 and the gas supply port 73, the gas is blown out from each gas outlet 70. The gas blown out from the gas outlets 70 may be air or a gas other than air. The gas supply unit 72 has at least the function of adjusting the amount of gas supplied. Furthermore, the gas supply unit 72 preferably has the function of suppressing fluctuations in the amount of gas supplied and the function of starting and stopping the gas supply as needed.

[0050] FIG. 8 is a cross-sectional view taken along line AA (nozzle arrangement direction X) in FIG. 6, showing how gas 8 is blown out from gas outlet 70 in the first embodiment of the present invention.

[0051] As shown in FIG. 8 , when droplets 10 are ejected from multiple nozzles 30, the air around the droplets 10 moves in the droplet ejection direction as the droplets 10 are ejected, as described above. At this time, the amount of air near the nozzles 30 decreases due to the movement of air, but the gas 8 blown out from the gas outlets 70 suppresses the air flow near the nozzles 30. That is, the air that has been removed is replaced with an equal amount of gas 8, thereby suppressing the air flow from around the nozzles 30 toward the nozzles 30. This suppresses the generation of airflows 9 (9A) in the nozzle arrangement direction X that flow from the outside to the inside of the nozzle array for the nozzles 30 at both ends, as shown in FIG. 19 or 21 . Furthermore, because the gas 8 is blown out from both sides of one nozzle 30, even if droplets 10 are not ejected from a nozzle 30 adjacent to a certain nozzle 30 or the amount of droplets 10 ejected from the adjacent nozzle 30 changes, the influence of changes in the airflow due to changes in droplet ejection or the amount of droplets is suppressed. For this reason, the generation of airflow 9 (9D) in the nozzle arrangement direction X in the region inside the nozzle row as shown in FIG. 21 is also suppressed.

[0052] In this way, in the first embodiment of the present invention, by blowing out gas 8 from gas outlet 70 during droplet ejection, it is possible to suppress the generation of airflow 9 (9A) in nozzle arrangement direction X that flows from the outside to the inside of the nozzle array with respect to nozzles 30 at both ends as shown in Figure 19 or Figure 21, and the generation of airflow 9 (9D) in nozzle arrangement direction X in the inner region of the nozzle array as shown in Figure 21. Therefore, with the configuration according to the first embodiment of the present invention, it is possible to effectively suppress deviation of droplet landing positions in nozzle arrangement direction X, thereby improving the landing accuracy of droplets 10.

[0053] Furthermore, the generation of the airflows 9 (9A, 9D) in the nozzle arrangement direction X is not limited to when the nozzle arrangement direction X is perpendicular to the sheet conveying direction Y, but can also occur when the nozzle arrangement direction X intersects with the sheet conveying direction Y at a direction other than perpendicular, and therefore the present invention is also applicable to cases where the nozzle arrangement direction X and the sheet conveying direction Y intersect at a direction other than perpendicular. Therefore, the nozzle arrangement direction X (first direction) and the relative movement direction Y (second direction) in which the sheet S and the nozzles 30 move relatively during droplet ejection may intersect at a direction other than perpendicular to each other, as well as when they are perpendicular to each other.

[0054] Furthermore, in the first embodiment of the present invention, the gas outlets 70 are disposed not only between the nozzles 30 but also at positions outside the nozzles 30 at both ends. This suppresses the generation of the airflows 9 (9B) on the sheet S side that flow outward from both ends of the nozzle array, as shown in FIG. 19 or 21 . This effectively suppresses deviations in the landing positions of the droplets at both ends of the nozzle array. In particular, when multiple gas outlets 70 are disposed at positions outside the nozzles 30 at both ends, as in the first embodiment of the present invention, deviations in the landing positions of the droplets 10 at both ends of the nozzle array can be more effectively suppressed. That is, when multiple gas outlets 70 are disposed at positions outside the nozzles 30 at both ends, the positions at which the airflows 9 (9B) on the sheet S side that flow outward from both ends of the nozzle array can be moved outward away from the positions of the nozzles 30 at both ends. This suppresses the generation of the outward airflows 9 (9B) at both ends of the nozzle array, thereby improving the landing accuracy of the droplets 10. In the example of Figure 6, three gas outlets 70 are arranged at positions outside the nozzles 30 on both ends, but the number of gas outlets 70 arranged outside the nozzles 30 on both ends may be one or two, or may be four or more.

[0055] The number of gas outlets 70 arranged between adjacent nozzles 30 can also be changed as appropriate. Therefore, the gas outlets 70 may be arranged only between the plurality of nozzles 30 arranged in a direction perpendicular or intersecting the sheet conveying direction Y, or at least one gas outlet 70 may be arranged between the plurality of nozzles 30. However, as shown in FIG. 6, it is preferable that the gas outlets 70 are arranged between all of the plurality of nozzles 30 arranged in the nozzle arrangement direction X (first direction). In this case, even if droplets 10 are not ejected from some of the plurality of nozzles 30, gas 8 is blown out from both sides of the nozzles 30 that eject droplets 10, thereby suppressing the effect of changes in the airflow 9 due to the presence or absence of droplet ejection, and reducing variation in the droplet landing positions.

[0056] Furthermore, in order to suppress the influence of changes in the airflow 9 due to the presence or absence of droplet ejection, it is preferable to control so that the gas 8 is always blown out during the droplet ejection operation or the sheet transport operation. In this case, even if some of the nozzles 30 stop ejecting droplets 10 during the droplet ejection operation or the sheet transport operation, or conversely, some of the nozzles 30 start ejecting droplets 10, the gas 8 is always blown out, so the influence of changes in the airflow due to the presence or absence of droplet ejection can be suppressed, and the landing accuracy of the droplets 10 can be improved.

[0057] Furthermore, to suppress the influence of changes in the airflow 9 due to the presence or absence of droplet ejection, it is preferable that the difference between the ejection speed of the droplets 10 ejected from the nozzle 30 and the blowing speed (speed in the blowing direction) of the gas 8 ejected from the gas outlet 70 be small. The impact of the ejection of the droplets 10 on the surrounding air is proportional to the speed difference between the ejection speed (speed in the ejection direction) of the droplets 10 and the speed of the airflow (gas 8). Therefore, it is preferable that the average blowing speed of the gas 8 be approximately the same as the average ejection speed of the droplets 10. Here, the ejection speed of the droplets 10 varies depending on the frequency value for opening and closing the nozzle 30 as well as on each nozzle 30. Therefore, considering the general variation in the ejection speed of the droplets 10, it is preferable to adjust the blowing speed of the gas 8 so that the average ejection speed of the droplets 10 is within ±20% of the average ejection speed of the gas 8. Furthermore, the average discharge speed of the droplets 10 varies depending on the specifications of the droplet discharge head 20, but is generally about 5 m / s or more and 10 m / s or less, so it is preferable that the average discharge speed of the gas 8 is 4 m / s or more and 12 m / s or less. Note that the average discharge speed of the droplets 10 here refers to the value obtained by dividing the distance in the droplet discharge direction between the nozzle 30 and the sheet S by the time from when the droplets 10 are discharged until they land on the sheet S.

[0058] FIG. 9 is a cross-sectional view taken along line BB (sheet conveying direction Y) in FIG. 6, showing how the gas 8 is blown out from the gas outlet 70 in the first embodiment of the present invention.

[0059] 9, in the first embodiment of the present invention, the gas outlet 70 is formed to extend longer in the sheet conveying direction Y (second direction) than the nozzle 30. In other words, if the downstream side of the nozzle 30 in the sheet conveying direction Y is defined as the "positive side," and the upstream side of the nozzle 30 in the sheet conveying direction Y is defined as the "negative side," the gas outlet 70 extends from the position of the nozzle 30 in the sheet conveying direction Y (second movement direction) to both the positive side and the negative side.

[0060] As described above, in the first embodiment of the present invention, the gas outlet 70 extends both downstream (positive side) and upstream (negative side) from the position of the nozzle 30 in the sheet conveying direction Y. Therefore, as shown in FIG. 9 , when the nozzle 30 is viewed from the nozzle arrangement direction X, the gas 8 is blown out not only from the position corresponding to (overlapping with) the nozzle 30, but also from positions upstream and downstream of that position. Here, the blown out gas 8 is influenced by the airflow 9 (9C) in the sheet conveying direction Y and flows downstream in the sheet conveying direction Y. However, even if the gas 8 blown out from the upstream side of the nozzle 30 flows in the sheet conveying direction Y, it flows through the droplet landing position and its vicinity. Therefore, the gas 8 flowing through the droplet landing position and its vicinity suppresses the generation of the airflow 9 in the nozzle arrangement direction X, and thus the deviation of the droplet landing position in the nozzle arrangement direction X is also effectively suppressed. Furthermore, since such an effect is obtained particularly by the gas 8 blown from upstream of the position of the nozzle 30, the gas outlet 70 may be arranged to extend only upstream from the position of the nozzle 30 in the sheet conveying direction Y.

[0061] Next, another embodiment of the present invention will be described. In the following description, differences from the first embodiment of the present invention will be mainly described, and descriptions of the same parts will be omitted as appropriate.

[0062] <Second embodiment of the present invention> FIG. 10 is a cross-sectional view taken along the sheet conveying direction Y, showing how the gas 8 is blown out from the gas blowout port 70 in the second embodiment of the present invention.

[0063] 10, when the gas outlet 70 is viewed from the nozzle arrangement direction X, the direction in which the gas 8 is blown out from the gas outlet 70 is inclined toward the downstream side of the sheet conveyance direction Y with respect to the direction in which the droplets 10 are ejected from the nozzles 30. On the other hand, in the first embodiment of the present invention, the direction in which the gas 8 is blown out is the same as the direction in which the droplets 10 are ejected (see FIG. 9).

[0064] In the first embodiment of the present invention, the blowing direction of the gas 8 is the same as the ejection direction of the droplets 10, so as shown in Fig. 9, part of the gas 8 blown onto the sheet S heads upstream in the sheet conveying direction Y and collides with the airflow 9 (9C) in the sheet conveying direction Y. Part of the airflow generated by this collision is returned toward the droplets 10 by the airflow (9C) in the sheet conveying direction Y. Therefore, when the blowing force of the gas 8 is particularly strong, this may cause the generation of an airflow 9 (9D) in the nozzle arrangement direction X in the region inside the nozzle array as shown in Fig. 21.

[0065] In contrast, in the second embodiment of the present invention, the blowing direction of the gas 8 is inclined toward the downstream side in the sheet conveying direction Y with respect to the ejection direction of the droplets 10 ejected from the nozzles 30, so that the gas 8 blown onto the sheet S is prevented from moving upstream in the sheet conveying direction Y. This makes it possible to avoid or prevent collision between the gas 8 and the airflow 9 (9C) in the sheet conveying direction Y upstream of the landing position of the droplets 10 in the sheet conveying direction Y, so that it is possible to more reliably prevent the generation of the airflow 9 (9D) in the nozzle arrangement direction X in the region inside the nozzle array as shown in FIG. 21 . Therefore, according to the second embodiment of the present invention, the blowing force of the gas 8 can be strengthened and the generation of the airflow 9 in the nozzle arrangement direction X can be more effectively prevented, so that further improvement in the landing accuracy of the droplets 10 can be expected.

[0066] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate within the scope of the gist of the invention.

[0067] In the above embodiment, the head unit according to the present invention has been described as a line-type head unit, but the present invention can also be applied to a so-called serial-type head unit in which ink is ejected while the droplet ejection head is moved in the main scanning direction (sheet width direction), in addition to the line-type head unit. Below, an example in which the present invention is applied to a serial-type head unit will be described.

[0068] <Configuration of serial type head unit> FIG. 11 is a plan view showing an example of a serial type head unit.

[0069] The serial type head unit 60 shown in Figure 11 includes a carriage 62 carrying a droplet ejection head 61, a guide member (guide rod) 63 for guiding the carriage 62 in the main scanning direction Z, which is the sheet width direction, and a drive device 64 for moving the carriage 62.

[0070] The drive device 64 has, for example, a motor 65 as a drive source, and a timing belt 68 wound around a drive pulley 66 and a driven pulley 67. When the motor 65 is driven and the drive pulley 66 rotates, the timing belt 68 moves in an orbit, causing the carriage 62 to move in the main scanning direction along the guide member 63. In addition, by switching the rotation direction of the motor 65 between one direction and the opposite direction, the carriage 62 can move back and forth in the main scanning direction Z.

[0071] 11, the sheet S is conveyed in the direction of the arrow Y, and when the sheet S reaches a predetermined image formation position, the carriage 62 moves in the main scanning direction Z while ejecting droplets (ink) from the droplet ejection head 61, thereby forming a line of image on the stationary sheet S. Thereafter, images are formed sequentially on the sheet S by repeating the movement and stopping of the sheet S in the direction of the arrow Y, the reciprocating movement of the droplet ejection head 61 (carriage 62), and the ejection operation of the droplet ejection head 61.

[0072] In this case, a plurality of nozzles 69 that eject droplets are arranged in a row in the sheet conveyance direction Y. In other words, the plurality of nozzles 69 are arranged in a direction perpendicular to or intersecting with the movement direction Z of the carriage 62. Here, in the serial type head unit 60, droplets are ejected from the nozzles 69 when the carriage 62 moves in the main scanning direction Z, so the relative movement direction in which the sheet S and the nozzles 69 move relative to each other during droplet ejection is the reciprocating movement direction Z of the carriage 62. Therefore, if the "first direction" is the nozzle arrangement direction X and the "second direction" is the relative movement direction Z between the sheet S and the nozzles 69 during droplet ejection, then the "first direction" is perpendicular to or intersects with the "second direction."

[0073] In this way, even in a serial type head unit 60 in which the "first direction" and the "second direction" are perpendicular to or intersect with each other, by applying the present invention, it is possible to effectively suppress deviation of the droplet landing position in the nozzle arrangement direction X, thereby improving the landing accuracy of the droplets 10.

[0074] 6, in the serial type head unit 60, by arranging gas outlets 70 between a plurality of nozzles 69 aligned in the nozzle arrangement direction X (first direction), it becomes possible to effectively suppress deviation of the landing positions of droplets 10 in the nozzle arrangement direction X by the gas 8 blown out from each gas outlet 70. Furthermore, as in the first embodiment of the present invention, in addition to being arranged between the nozzles 69, gas outlets 70 may also be arranged at positions outside the nozzles 30 on both ends.

[0075] 12, in the case of a serial type, when the gas outlet 70 is viewed from the nozzle arrangement direction X, it is preferable that the gas outlet 70 extend both to the positive side and the negative side from the position of the nozzle 30 in the reciprocating movement direction Z (second direction) of the droplet discharge head 61. Since the gas outlet 70 extends both to the positive side and the negative side in this manner, for example, as shown in FIG. 13, when the droplet discharge head 61 moves in one direction Z1, the relative movement direction of the sheet S with respect to the nozzle 69 is the direction indicated by the dashed arrow in the figure, which is opposite to the movement direction Z1 of the droplet discharge head 61, and therefore the gas 8 is blown out from the upstream side (left side of the figure) of the position of the nozzle 69 in the relative movement direction of the sheet S (direction of the dashed arrow). Conversely, when the droplet discharge head 61 moves in the opposite direction Z2 as shown in FIG. 14, the gas 8 is blown out from the upstream side (right side of the figure) of the position of the nozzle 69 in the relative movement direction of the sheet S indicated by the dashed arrow in the figure. In this way, the gas outlet 70 extends to the positive and negative sides from the position of the nozzle 69 in the relative movement direction (second direction) of the sheet S, so that the gas 8 can be blown out from the upstream side of the nozzle 69 on both the outward and return paths when the droplet ejection head 61 moves back and forth. This has the effect of suppressing deviation of the droplet landing positions in the nozzle arrangement direction X by the gas 8 blown out from the upstream side, so that the landing accuracy of the droplets 10 can be improved even in the serial type head unit 60.

[0076] 15, the nozzles 30 may be arranged so as to line up in both the sheet transport direction Y (second direction) and a direction intersecting the sheet transport direction Y. In such an example, by providing gas outlets 70 between the nozzles 30 arranged in the direction intersecting the sheet transport direction Y (the direction of the arrow X in the figure), it becomes possible to effectively suppress deviation of the landing positions of the droplets 10 in the nozzle arrangement direction X (first direction), as in the above-described embodiment of the present invention.

[0077] Furthermore, the droplet ejection head and head unit according to the present invention can be applied to image forming apparatuses, which are an example of droplet ejection devices, as well as other droplet ejection devices.

[0078] For example, the droplet ejection head and head unit according to the present invention can also be applied to an electrode and electrochemical element manufacturing apparatus that manufactures electrodes by ejecting a liquid composition. That is, the "droplet ejection apparatus" according to the present invention includes not only an image forming apparatus that forms an image on a sheet, but also an electrode and electrochemical element manufacturing apparatus. The electrode manufacturing apparatus will be described below.

[0079] <Electrode manufacturing equipment> FIG. 16 is a schematic diagram showing an example of an electrode manufacturing apparatus according to an embodiment of the present invention.

[0080] The electrode manufacturing apparatus of FIG. 16 is an apparatus for manufacturing an electrode including a layer having an electrode material by ejecting a liquid composition using a head unit including a droplet ejection head.

[0081] <Means for forming layer containing electrode material, and process for forming layer containing electrode material> The discharge means provided in the electrode manufacturing apparatus shown in FIG. 16 is configured with a head unit having the same configuration as the head unit according to the embodiment of the present invention. However, the droplet discharge head provided in the head unit discharges a liquid composition for manufacturing an electrode, rather than ink. When the liquid composition is discharged from the liquid discharge head onto a target, a liquid composition layer is formed. The target onto which the liquid composition is discharged (hereinafter, sometimes referred to as the "discharge target") is not particularly limited as long as it is an object on which a layer containing an electrode material is to be formed, and can be appropriately selected depending on the purpose. For example, the target may be an electrode substrate (current collector), an active material layer, a layer containing a solid electrode material, etc. Alternatively, the target may be an electrode mixture layer containing an active material on an electrode substrate (current collector). Alternatively, the discharge means and discharge step may be a means and step for directly discharging a liquid composition to form a layer containing an electrode material on the discharge target, as long as it is possible to form a layer containing an electrode material on the discharge target. Alternatively, the discharge means and discharge step may be a means and step for indirectly discharging a liquid composition to form a layer containing an electrode material.

[0082] <Other components and processes> Other components included in the manufacturing apparatus for an electrode mixture layer are not particularly limited as long as they do not impair the effects of the present invention, and can be selected appropriately depending on the purpose. Furthermore, other steps included in the manufacturing method for an electrode mixture layer are also not particularly limited as long as they do not impair the effects of the present invention, and can be selected appropriately depending on the purpose. For example, components and steps included in the manufacturing apparatus and manufacturing method for an electrode mixture layer include a heating means and a heating step.

[0083] <Heating means, heating process> The heating means included in the manufacturing device for the electrode mixture layer is a means for heating the liquid composition ejected by the ejection means. Also, the heating step included in the manufacturing method for the electrode mixture layer is a step of heating the liquid composition ejected in the ejection step. By heating the liquid composition, the liquid composition layer can be dried.

[0084] <Configuration for forming a layer containing an electrode material by directly ejecting a liquid composition> Here, as an example of an electrode manufacturing apparatus, an electrode manufacturing apparatus that forms an electrode mixture layer containing an active material on an electrode substrate (current collector) will be described. As shown in Fig. 16, the electrode manufacturing apparatus includes a discharge process unit 110 that includes a process of applying a liquid composition to a printing substrate 704 having an object to be discharged to form a liquid composition layer, and a heating process unit 130 that includes a heating process of heating the liquid composition layer to obtain an electrode mixture layer.

[0085] The electrode manufacturing apparatus also includes a transport unit 705 that transports the printing substrate 704. The transport unit 705 transports the printing substrate 704 at a preset speed through the discharge process unit 110 and then the heating process unit 130. There are no particular limitations on the method for manufacturing the printing substrate 704 having a discharge target such as an active material layer, and any known method can be selected as appropriate. The discharge process unit 110 includes a droplet discharge head 281a that performs the application step of applying a liquid composition onto the printing substrate 704, a storage container 281b that stores the liquid composition 707, and a supply tube 281c that supplies the liquid composition 707 stored in the storage container 281b to the droplet discharge head 281a.

[0086] In the discharge process unit 110, the liquid composition 707 is discharged from the droplet discharge head 281a and applied to the printing substrate 704, thereby forming a thin film of the liquid composition layer. The storage container 281b may be configured as an integral part of the manufacturing apparatus for the electrode mixture layer, or may be configured as a removable part from the manufacturing apparatus for the electrode mixture layer. The storage container 281b may be a container used for adding the liquid to a storage container that is integrated with the manufacturing apparatus for the electrode mixture layer, or a storage container that is removable from the manufacturing apparatus for the electrode mixture layer.

[0087] The storage container 281b and the supply tube 281c can be arbitrarily selected as long as they can stably store and supply the liquid composition 707.

[0088] In the heating process section 130, a solvent removal step is carried out in which the solvent remaining in the liquid composition layer is heated and removed. Specifically, the solvent remaining in the liquid composition layer is heated and dried by the heating device 703 in the heating process section 130, thereby removing the solvent from the liquid composition layer. This results in the formation of an electrode mixture layer. The solvent removal step in the heating process section 130 may also be carried out under reduced pressure.

[0089] The heating device 703 is not particularly limited and can be appropriately selected depending on the purpose. For example, the heating device 703 can be a substrate heater, an IR heater, a hot air heater, or the like. The heating device 703 may also be a combination of at least two of the substrate heater, the IR heater, and the hot air heater. The heating temperature and heating time can be appropriately selected depending on the boiling point of the solvent contained in the liquid composition 707 or the thickness of the formed film.

[0090] By using the electrode manufacturing apparatus according to an embodiment of the present invention, a liquid composition can be ejected onto a target object. The electrode mixture layer can be suitably used, for example, as part of the configuration of an electrochemical element. The components other than the electrode mixture layer in the electrochemical element are not particularly limited, and known components can be appropriately selected. For example, components other than the electrode mixture layer include a positive electrode, a negative electrode, a separator, and the like.

[0091] Furthermore, the sheet used in the present invention may be any material that can at least temporarily adhere to a liquid, and that can adhere and solidify to or penetrate the liquid. Specifically, examples of the sheet include paper, resin films, wallpaper, electronic substrates, and the like. Examples of the material of the sheet include paper, leather, metal, plastic, glass, wood, and ceramics. Furthermore, the sheet is not limited to a long sheet that is transported continuously and without interruption from the sheet supply unit to the sheet recovery unit, but may also be a short sheet that is transported individually and not continuously from the sheet supply unit to the sheet recovery unit.

[0092] The liquid applied to the sheet is not particularly limited, but includes solutions, suspensions, emulsions, etc. containing solvents such as water and organic solvents, colorants such as dyes and pigments, functional 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 are used, for example, in inkjet inks, surface treatment solutions, components of electronic elements and light-emitting elements, liquids for forming electronic circuit resist patterns, and material liquids for 3D modeling.

[0093] To summarize the above-described aspects of the present invention, the present invention includes at least the following aspects.

[0094] [First aspect] The first aspect is a droplet ejection head having a plurality of nozzles that eject droplets onto a sheet, where the direction in which the plurality of nozzles are arranged is defined as a first direction and the direction in which the sheet and the nozzles move relative to each other during droplet ejection is defined as a second direction, and the first direction and the second direction intersect with each other, and the droplet ejection head has at least one gas outlet for ejecting gas between the plurality of nozzles that are arranged in the first direction.

[0095] [Second aspect] In a second aspect, in the first aspect, the gas outlet is arranged between the plurality of nozzles lined up in the first direction, and also outside the nozzle positioned at the outermost position in the first direction.

[0096] [Third aspect] A third aspect is the first or second aspect, wherein the gas outlets are arranged between all of the nozzles among the plurality of nozzles aligned in the first direction.

[0097] [Fourth aspect] A fourth aspect is any one of the first to third aspects, wherein the gas outlet extends upstream from the position of the nozzle in the direction of relative movement of the sheet.

[0098] [Fifth aspect] In a fifth aspect, in the fourth aspect, the direction in which the gas is blown out from the gas outlet is inclined toward the downstream side of the relative movement direction of the sheet with respect to the ejection direction of the droplets ejected from the nozzle.

[0099] [Sixth aspect] A sixth aspect is any one of the first to third aspects, wherein the gas outlet extends from the position of the nozzle in the second direction to at least one of the positive side and the negative side.

[0100] [Seventh aspect] A seventh aspect is any one of the first to third aspects, wherein the gas outlet extends to both the positive side and the negative side from the position of the nozzle in the second direction.

[0101] [Eighth aspect] An eighth aspect is any one of the first to seventh aspects, wherein the average speed of the gas blown out from the gas outlet in the blowing direction is 4 m / s or more and 12 m / s or less.

[0102] [Ninth aspect] A ninth aspect is a head unit including a plurality of droplet ejection heads according to any one of the first to eighth aspects.

[0103] [Tenth aspect] A tenth aspect is a droplet ejection device comprising any one of the droplet ejection heads according to the first to eighth aspects, or the head unit according to the ninth aspect. [Explanation of symbols]

[0104] 8. Gas 9. Airflow 10 droplets 13 Head Unit 20 Droplet ejection head 30 nozzles 70 Gas outlet 100 Image forming device (liquid ejection device) S seat X Nozzle arrangement direction (first direction) Y Sheet transport direction (second direction) Z: Reciprocating movement direction of the droplet ejection head (second direction) [Prior art documents] [Patent documents]

[0105] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-175243

Claims

1. a plurality of nozzles for ejecting droplets onto a sheet; In a droplet ejection head in which a direction in which the plurality of nozzles are arranged is defined as a first direction, and a direction in which the sheet and the nozzles move relatively to each other during droplet ejection is defined as a second direction, the first direction and the second direction intersect with each other, A droplet ejection head comprising at least one gas outlet for ejecting gas between the plurality of nozzles aligned in the first direction.

2. The droplet ejection head according to claim 1 , wherein the gas outlets are arranged between the plurality of nozzles aligned in the first direction and also outside the nozzles positioned at the outermost positions in the first direction.

3. The droplet ejection head according to claim 1 , wherein the gas outlets are arranged between all of the plurality of nozzles aligned in the first direction.

4. The droplet ejection head according to claim 1 , wherein the gas outlet extends upstream from the position of the nozzle in the direction of relative movement of the sheet.

5. 5. The droplet ejection head according to claim 4, wherein the direction of gas ejected from the gas ejection port is inclined toward a downstream side in the relative movement direction of the sheet with respect to the ejection direction of droplets ejected from the nozzle.

6. The droplet ejection head according to claim 1 , wherein the gas outlet extends from the position of the nozzle in the second direction to at least one of the positive side and the negative side.

7. The droplet ejection head according to claim 1 , wherein the gas outlet extends from the position of the nozzle in the second direction to both the positive side and the negative side.

8. 2. The droplet ejection head according to claim 1, wherein the average speed in the direction of gas ejected from the gas ejection port is 4 m / s or more and 12 m / s or less.

9. A head unit comprising a plurality of droplet ejection heads according to claim 1.

10. A droplet ejection device comprising the droplet ejection head according to claim 1.

Images