Inkjet head, line head, inkjet device, and method for manufacturing inkjet head

Abstract

The inkjet head includes: a plurality of drive unit rows in which drive units are arranged at a pitch (p); and a plurality of nozzles disposed at positions corresponding to the respective drive units and configured to eject ink by driving of the drive units, the plurality of drive unit rows including a first drive unit row and a second drive unit row disposed on the same straight line, the shortest distance (D) between the drive unit located on the second drive unit row side among the drive units included in the first drive unit row and the drive unit located on the first drive unit row side among the drive units included in the second drive unit row is a non-integer multiple of the pitch (p).

Description

Technical Field

[0001] This disclosure relates to inkjet heads, line printheads, inkjet devices, and methods for manufacturing inkjet heads. Background Technology

[0002] In recent years, the method of manufacturing devices using inkjet equipment has attracted attention. Inkjet equipment has multiple nozzles that eject droplets, and while controlling the positional relationship between the nozzles and the object to be printed, it ejects droplets from the nozzles, thereby coating the object with droplets.

[0003] As one type of inkjet device, there exists an inkjet device having multiple modular heads (i.e., droplet ejector heads with multiple ejection outlets) arranged side by side in the width direction of the printed object, which are called line printheads.

[0004] By arranging the row printheads in a direction orthogonal to the printing direction, ink can be applied to a wide printing object in a single transport step. Furthermore, by mounting multiple row printheads arranged side by side in the printing direction, multiple inks of different colors can be applied to the printing object in a single transport step.

[0005] According to this structure, even for large printed objects of G8 size or larger, multiple inks can be applied in a single transport process. This reduces the production cycle time for applying ink to the printed object and makes it easier to achieve uniform drying conditions after ink application. Therefore, it has advantages in printing process such as the ability to uniformly control ink film thickness.

[0006] To address the increasing precision required for printed objects, it is preferable to increase the nozzle density in the direction orthogonal to the printing direction (i.e., the resolution of the ejector nozzles in a line printhead). On the other hand, from the viewpoint of printing unevenness, it is preferable to have a smaller distance between nozzles in the printing direction (i.e., the depth and width of the printing area in a line printhead). Preferably, the nozzle resolution is, for example, 2400 dpi, and the depth and width of the printing area in the line printhead is 80 mm or less.

[0007] In addition, to improve the resolution of the ejection nozzles, the method of narrowing the spacing between adjacent nozzles is considered. However, due to the mutual influence between adjacent nozzles, known as crosstalk, there is a problem of deterioration in ejection accuracy, and there is a limit to narrowing the nozzle spacing.

[0008] On the other hand, inkjet devices that have studied the configuration of nozzles are known (for example, see Patent Document 1). As described in Patent Document 1, by arranging the inkjet head at an angle relative to the printing direction and arranging the positional relationship of the nozzle rows in a phase-shifted manner, the depth width of the printing area of ​​the line printhead can be reduced, and the nozzle resolution can be increased to about 1200 dpi.

[0009] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 5857205 Summary of the Invention

[0010] The inkjet head disclosed herein comprises: a plurality of drive units arranged at a distance p; and a plurality of nozzles disposed at positions corresponding to the drive units, which eject ink by being driven by the drive units. The plurality of drive units have a first drive unit and a second drive unit arranged on the same straight line. The shortest distance D between the drive unit located on the side of the second drive unit in the first drive unit and the drive unit located on the side of the first drive unit in the second drive unit is a non-integer multiple of the distance p.

[0011] The line printhead disclosed herein has multiple inkjet heads as described above.

[0012] The inkjet apparatus disclosed herein includes: the above-described line printhead; a transport table for holding a printing object to be coated with the ink; and a drive device for moving the line printhead relative to the transport table.

[0013] In the inkjet head manufacturing method disclosed herein, the drive unit and a component constituting the pressure chamber for storing the ink are joined together by sandwiching a thermosetting adhesive that cures at a temperature below 70°C, and the thermosetting adhesive is thermosetting at a temperature below 70°C to manufacture the inkjet head. Attached Figure Description

[0014] Figure 1 This is a diagram of an inkjet device viewed from a plane.

[0015] Figure 2 It is an exploded 3D view showing the overall structure of the inkjet head.

[0016] Figure 3 This is a cross-sectional view of the area near the nozzle of the inkjet head.

[0017] Figure 4A This indicates cutting along the YZ plane. Figure 3 A cross-sectional view of an example of the cross-section obtained by the driving body shown.

[0018] Figure 4B This indicates cutting along the YZ plane. Figure 3 A cross-sectional view of an example of the cross-section obtained by the driving body shown.

[0019] Figure 4C This diagram illustrates an example of a structure where the control wiring is on a flexible printed circuit board.

[0020] Figure 5A This diagram illustrates the machining method of the drive unit when it has a column section.

[0021] Figure 5B This diagram illustrates the machining method of the drive unit when there is no column.

[0022] Figure 6A This is a diagram illustrating the drive unit of the thermal injection method.

[0023] Figure 6B This is a diagram illustrating the drive unit of the shear mode.

[0024] Figure 6C This is a diagram illustrating the drive unit for the exhaust system.

[0025] Figure 6D This diagram illustrates the time-sharing injection control of the drive unit in the shared mode.

[0026] Figure 7 This diagram illustrates the relationship between the inkjet head and the drive unit.

[0027] Figure 8A This is a diagram illustrating the arrangement of the drive unit.

[0028] Figure 8B This indicates the positional relationship between the drive unit and the inkjet head.

[0029] Figure 8C This diagram illustrates the configuration where the inkjet head is tilted relative to the printing direction.

[0030] Figure 8D This diagram illustrates the nozzle array used to achieve high-precision printing.

[0031] Figure 9A This diagram illustrates the relationship between the configuration of the drive unit and the printing resolution.

[0032] Figure 9B This diagram illustrates the nozzle array used to achieve high-precision printing.

[0033] Figure 9C This is a cutout of the four nozzle rows on the drive unit when multiple inkjet heads are arranged side by side.

[0034] Figure 9D It is a diagram showing the position of the nozzles in the Y' direction of each nozzle row.

[0035] Figure 10A This is a diagram showing a first modified example of the structure of the drive body and drive assembly.

[0036] Figure 10B This is a diagram showing a second variation of the structure of the drive body and drive assembly.

[0037] Figure 10C This is a diagram showing a third variation of the structure of the drive body and drive assembly.

[0038] Figure 10D This is a diagram showing a fourth variation of the structure of the drive body and drive assembly.

[0039] Figure 10E This is a diagram illustrating an example of a nozzle array in a case where a drive unit has multiple drive units in the X direction.

[0040] Figure 10F This is a diagram showing the fifth variation of the structure of the drive body and drive assembly.

[0041] Figure 10G This is a diagram showing a sixth variation of the structure of the drive body and drive assembly.

[0042] Figure 11 This diagram illustrates how to deal with the warping of the driving body itself.

[0043] Explanation of reference numerals in the attached figures 1 Inkjet unit; 2 Base; 3 Guide; 4 Transport table; 5 Gantry; 6 Head unit; 7 Printing object; 8 Drive unit; 10 Housing; 20 Vibrating plate; 30 Flow path plate; 33 Pressure chamber; 40 Nozzle plate; 41 Nozzle; 50, 110, 111 Drive body; 52, 53 Electrode layer; 54, 61 Drive section; 55, 62 Column section; 60 Base section; 70 Flow path section; 80 FPC section; 94, 95 Piezoelectric element; 100 Inkjet head; 115, 116, 117, 118 Drive section array. Detailed Implementation

[0044] To achieve even higher resolution, the nozzle array length needs to be increased to steepen the inkjet head tilt angle. This results in a larger inkjet head size and a greater depth and width of the printing area for line printheads. As mentioned above, narrowing the nozzle spacing can also be considered, but there are limitations.

[0045] The purpose of this disclosure is to provide an inkjet head, a line printhead, an inkjet device, and a method for manufacturing an inkjet head, which can achieve both miniaturization of the inkjet head and reduction of the depth and width of the printing area of ​​the line printhead, and can perform high-precision printing.

[0046] The inkjet head in the embodiments of this disclosure will now be described with reference to the accompanying drawings. This disclosure is not limited to the following embodiments, and various modifications can be made without departing from the spirit of this disclosure.

[0047] First, refer to Figure 1 Instructions for inkjet device 1. Figure 1 This is a diagram of the inkjet device 1 as viewed from a planar perspective. (See diagram below.) Figure 1 As shown, the long side direction of the inkjet device 1 is set as the X' direction, the short side direction is set as the Y' direction, and the direction perpendicular to the X' and Y' directions is set as the Z direction.

[0048] The inkjet unit 1 includes a base 2, a guide 3, a conveyor 4, a gantry 5, a head unit 6, and a drive unit 8.

[0049] The base 2 is a rectangular planar platform with a long strip in the scanning direction (X' direction) of the head unit 6.

[0050] The guide 3 is fixed to the upper surface of the base 2 along the scanning direction of the head unit 6. As an example, the guide 3 is a cuboid component with a rectangular cross-section orthogonal to the scanning direction.

[0051] The transport stage 4 has a rectangular shape, and its lower surface (the surface on the -Z side) contacts the guide member 3. The transport stage 4 is guided by the guide member 3 and transported in the scanning direction of the base 2. The substrate or other printing objects 7 are placed on the transport stage 4.

[0052] The gantry 5 has a gantry shape and is a supporting component of the support head unit 6. When viewed in a plane (from the +Z side), the gantry 5 is fixed to a predetermined position, such as the middle position, of the base 2 in a manner that spans the short side of the base 2.

[0053] Head unit 6 is an example of an ink ejector head, supported by gantry 5. Head unit 6 ejects ink toward the printing object 7 according to the timing of the object 7 passing below it. Thus, ink is applied to the coating area of ​​the printing object 7.

[0054] For example, head unit 6 is a line printhead having multiple inkjet heads 100 described later.

[0055] Furthermore, in this structure, such as Figure 1 As shown, two head units 6 are respectively arranged on both sides of the gantry 5. However, only one head unit 6 may be arranged on the gantry 5, or two head units 6 may be arranged on both sides of each gantry 5. The number and arrangement of head units 6 can also be changed according to the processing of the printing object 7 by the head units 6.

[0056] In addition, in order to drive the transport stage 4 in the scanning direction, at least one drive device 8 is disposed on the base 2 along the scanning direction and connected to the transport stage 4 to drive the transport stage 4 in the scanning direction.

[0057] exist Figure 1 In this embodiment, as an example of a drive device 8, two drive devices 8 extending along the scanning direction are arranged near both ends of the base 2 in the short side direction. Each drive device 8 can be a linear motor, or it can be a ball screw or the like connected to a rotary motor. In this structure, the case where the drive device 8 is a linear motor is illustrated.

[0058] Here, the drive unit 8 moves the conveyor table 4 relative to the head unit 6, but the inkjet unit 1 only needs to move the head unit 6 relative to the conveyor table 4.

[0059] In addition, such as Figure 1 As shown, when the head unit 6 is a row printhead type head unit arranged across the entire width of the inkjet device 1 in the Y' direction, the head unit 6 can apply ink to the printing object 7 at the same time, thus enabling efficient printing of a large number of printed materials.

[0060] On the other hand, there are also cases where the head unit 6 is not configured to cover the entire width of the inkjet unit 1 in the Y' direction. In this case, the inkjet unit 1 performs printing in a multi-pass scanning manner.

[0061] In multi-pass scanning printing, the head unit 6 reciprocates multiple times over the printing object 7 to print multiple lines. Therefore, the inkjet unit 1 can precisely print specific areas, suppress ink waste, and reduce costs. This type of multi-pass scanning printing is sometimes referred to as strip coating.

[0062] Next, the overall structure of the inkjet head 100 mounted on the head unit 6 will be explained. Figure 2 This is an exploded perspective view showing the overall structure of the inkjet head 100. Figure 2 In this example, an orthogonal coordinate system represented by (X, Y, Z) is used for illustration.

[0063] exist Figure 2 In the diagram, the +Z direction is the direction in which the ink is ejected from the inkjet head 100, the Y direction is the direction of the long side of the inkjet head 100 (the direction in which the nozzles are arranged), and the X direction is the width direction of the inkjet head 100. Additionally, the Z direction is the stacking direction of the plates that form the components of the inkjet head 100.

[0064] The inkjet head 100 has a housing part 10, a vibrating plate 20, a flow path plate 30, a nozzle plate 40, a drive body 50, a base part 60, and an FPC (flexible printed circuit board) part 80.

[0065] The drive unit 50 is located at the lower end of the base portion 60. The upper part of the housing portion 10 has an opening through which the drive unit 50 and the base portion 60 are housed. The FPC portion 80 is connected to the drive unit 50, and an electrical connection is made between each drive portion provided on the drive unit 50 and a control portion (not shown).

[0066] A flow path 70 is provided on the lower surface of the housing portion 10, separated by a vibrating plate 20. The flow path 70 includes a flow path plate 30 and a nozzle plate 40. The vibrating plate 20, the flow path plate 30, and the nozzle plate 40 are fixed in a stacked manner.

[0067] The nozzle plate 40 and the flow path plate 30, the flow path plate 30 and the vibrating plate 20, the vibrating plate 20 and the housing part 10, the vibrating plate 20 and the drive body 50, the base part 60 and the vibrating plate 20, and the base part 60 and the drive body 50 are respectively fixed by adhesives or the like.

[0068] As an adhesive, for example, an epoxy-based adhesive with thermosetting properties can be used. Alternatively, the same adhesive can be used as the adhesive for joining the various components, or different adhesives can be used separately. For example, a combination of rubber-based adhesives and epoxy-based adhesives can also be used.

[0069] Next, the structure near the nozzle of the inkjet head 100 will be described. Figure 3 This is a cross-sectional view of the area near nozzle 41 of inkjet head 100.

[0070] The nozzle plate 40 is formed, for example, by etching and stamping a 100 μm thick stainless steel plate. Multiple nozzles 41 are disposed throughout the nozzle plate 40 in the Y direction.

[0071] The flow path plate 30 is rectangular in shape. The flow path plate 30 is formed, for example, by stacking stainless steel plate components with a thickness of 10 to 100 μm, which are formed by etching and stamping. The number of layers is, for example, 3 to 10.

[0072] The flow path plate 30 has a plurality of pressure chambers 33 that are connected one-to-one with a plurality of nozzles 41, and a silo section 36 that connects the pressure chambers 33 with the nozzles 41.

[0073] The pressure chamber 33 is formed in the flow path plate 30 as a cuboid extending in the X direction, and the upper wall forming the upper side (-Z direction) is formed by the vibrating plate 20. Alternatively, the pressure chamber 33 may not be a cuboid, but may have multiple steps inside.

[0074] The silo section 36 connects the pressure chamber 33 and the nozzle 41, and stores ink. The silo section 36 is formed along the Z direction.

[0075] The flow path plate 30 has: an upstream individual flow path section 32, which is connected to the pressure chamber 33 in a one-to-one manner on the upstream side; an upstream common flow path section 31, which is connected to a plurality of upstream individual flow path sections 32; a downstream individual flow path section 34, which is connected to the pressure chamber 33 in a one-to-one manner on the downstream side; and a downstream common flow path section 35, which is connected to a plurality of downstream individual flow path sections 34.

[0076] The vibrating plate 20 is, for example, a thin film with a thickness of 5 to 50 μm, formed of Ni. In addition, the vibrating plate 20 has an upstream opening 21 disposed directly above the upstream common flow path 31 (in the -Z direction) and a downstream opening 22 disposed directly above the downstream common flow path 35 (in the -Z direction).

[0077] The housing portion 10 is formed in a cuboid shape. The housing portion 10 is formed by machining alloy steel such as stainless steel. The thickness of the housing portion 10 in the Z direction is, for example, about 1 cm.

[0078] The housing portion 10 has an upstream common flow path 12 disposed directly above the upstream opening portion 21 (in the -Z direction) and a downstream common flow path 14 disposed directly above the downstream opening portion 22 (in the -Z direction).

[0079] An upstream common flow path L1 is formed by the upstream common flow path 12 of the housing portion 10, the upstream opening 21 of the vibrating plate 20, and the upstream common flow path 31 of the flow path plate 30. A downstream common flow path L2 is formed by the downstream common flow path 14 of the housing portion 10, the downstream opening 22 of the vibrating plate 20, and the downstream common flow path 35 of the flow path plate 30.

[0080] Additionally, the housing portion 10 has an ink inlet path (not shown) for introducing ink from the outside and an ink outlet path (not shown) for discharging ink from the outside. The ink introduced into the upstream common flow path L1 via the ink inlet path is sequentially discharged from the ink outlet path via the upstream common flow path L1, the upstream individual flow path portion 32, the pressure chamber 33, the downstream individual flow path portion 34, and the downstream common flow path L2.

[0081] The drive unit 50 is disposed inside the housing portion 10 and imparts pressure variation to the ink in the pressure chamber 33. This pressure variation is transmitted toward the nozzle 41, from which ink is ejected.

[0082] Furthermore, a protrusion 24 protruding in the -Z direction is formed on the vibrating plate 20, through which the movement of the drive body 50 is input. Multiple protrusions 24 are formed in a Y-direction arrangement at positions corresponding to the nozzle 41.

[0083] The drive unit 50 is composed of a piezoelectric element. Specifically, the drive unit 50 has a drive section (not shown) that is driven by inserting electrode layers 52 and 53 into the piezoelectric element and providing electrical signals to the electrode layers 52 and 53. The drive section is provided in a one-to-one correspondence with the nozzle 41 and is separated into multiple channels by a cutout (not shown).

[0084] The drive unit 50 is a piezoelectric element supported by a base portion 60. The base portion 60 is a support for the drive unit 50. Furthermore, a control wiring 51 for controlling the drive unit 50 is mounted on the drive unit 50. The control wiring 51 is electrically connected to the drive unit 50. The control wiring 51 is equivalent to... Figure 2 The FPC section 80 is shown.

[0085] The actuator 50 is configured to contact the protrusion 24 of the vibrating plate 20, which forms the upper sidewall (-Z direction sidewall) of the pressure chamber 33, via an adhesive. The actuator 50 deforms in a stretching-extension manner along the Z direction when a voltage is applied. The actuator 50 is, for example, a stacked piezoelectric actuator of the D33 mode.

[0086] The drive body 50 deforms in a manner extending along the Z direction, pressing the protrusion 24 downward (in the +Z direction). As a result, the upper sidewall (in the -Z direction) of the pressure chamber 33 deforms, generating pressure fluctuations in the ink within the pressure chamber 33.

[0087] The pressure change is transmitted to the nozzle 41 via the silo section 36, thereby ejecting ink from the nozzle 41 to the outside. In this way, the ink ejection is controlled by the operation of the drive body 50.

[0088] Next, use Figures 4A-4C The structure of the drive body 50 and the flexible substrate that enables the drive body 50 to conduct with the control wiring 51 will be explained. Figure 4A and Figure 4B It means to Figure 3 A cross-sectional view of an example of the cross-section of the drive body 50 after it has been cut by the YZ plane. Figure 4C This is a diagram illustrating an example of the structure of a flexible substrate.

[0089] The drive body 50 is a piezoelectric element such as a PZT element. Furthermore, the drive body 50 is not limited to pressure elements such as PZT elements; it can be any structure capable of displacing ink based on digital electrical signals.

[0090] like Figure 4A As shown, in this drive body 50, multiple electrode layers 52 and 53 are inserted into the piezoelectric element. For example, electrode layer 52 is connected to GND, and electrode layer 53 is connected to a control unit that applies a voltage of 0 to 50V, thereby applying a voltage between electrode layer 52 and electrode layer 53.

[0091] By applying voltage, the piezoelectric element expands and contracts in the Z-direction, thus applying a force to compress the ink in the +Z direction. Furthermore, by adjusting the applied voltage, the amount and speed of droplet ejection can be adjusted. This function is known as DPN (Drive Per Nozzle).

[0092] The drive unit 50 has a drive portion 54, a pillar portion 55, and a cutout portion 56. The drive portion 54 and the pillar portion 55 are each held by two cutout portions 56. The drive portion 54 is a piezoelectric element that is electrically connected to the control wiring 51 and has an electrode layer 53 with which a voltage is applied inserted. The pillar portion 55 is a non-drive portion and is a piezoelectric element that is not electrically connected to the control wiring 51 and has an electrode layer 52 with no voltage applied inserted.

[0093] In addition, a pressure chamber 33 and a nozzle 41, which are composed of a vibrating plate 20, a flow path plate 30 and a nozzle plate 40, are each arranged at a position corresponding to a plurality of drive units 54.

[0094] The drive unit 54 is driven by an electrical signal supplied from the control wiring 51. Preferably, the control wiring 51 and the drive unit 50 are joined by an anisotropic conductive film (ACF) or the like. The cut portion 56 is formed by a cutting device or the like. The thickness of the cutting blade is, for example, 30 μm.

[0095] In this structure, the drive section 54 and the pillar section 55 are arranged alternately. By providing such a pillar section 55, a phenomenon called crosstalk that occurs when voltages are applied to adjacent drive sections 54 simultaneously can be mitigated.

[0096] In addition, such as Figure 4B As shown, the drive section 54 can also be arranged continuously without the column section 55. In this case, it is also consistent with... Figure 4A Similarly, pressure chamber 33 and nozzle 41 are each arranged at a position corresponding to the plurality of drive units 54.

[0097] Figure 4C This diagram illustrates an example of the structure when the control wiring 51 is a flexible printed circuit board. The flexible printed circuit board has a connection portion 51a connected to the drive body 50 and a connection portion 51b connected to control portions such as the control board. Furthermore, a wiring pattern is formed on a flexible material such as polyimide in the portion between the connection portion 51a and the connection portion 51b.

[0098] Furthermore, as shown in the enlarged view of the connection portion 51a, wiring is formed in the drive channel portion 57 connected to the drive body 50 to match the configuration of the drive unit 54, and each wiring is connected to the electrode layer 53 of the drive unit 54. Similarly, multiple wirings are also formed in the GND portion 58, which are connected to the electrode layer 52 of the drive unit 54.

[0099] For example, preferably, the electrode layer 52 is connected to the GND portion 58 via a GND electrode and an ACF (Anisotropic Conducting Film) applied to the side or inside of the drive body 50, and the electrode layer 53 is connected to the drive channel portion 57 via the ACF. However, the method of connection with the GND portion 58 is not limited to this.

[0100] Next, the machining method of the drive unit 54 will be explained. Figure 5A This diagram illustrates the machining method of the drive unit 54 when it has a column portion 55. Figure 5B This diagram illustrates the machining method of the drive unit 54 when the column 55 is not present.

[0101] like Figure 5A As shown, a cut portion is formed by using a cutting device or the like, and selectively connected to a control wiring 51 (not shown), thereby forming a drive body 50 in which the drive portion 54 and the column portion 55 are alternately arranged.

[0102] Furthermore, the cutting blade 59 rotates and moves along the X direction to form a notch by penetrating the drive body 50, so the drive part 54 and the column part 55 are arranged along the Y direction.

[0103] For example, 100 to 800 drive units 54 are arranged along the Y direction, most of these drive units 54 are arranged at equal intervals with a spacing p, and at least some of them are arranged at a spacing p' different from the spacing p.

[0104] Thus, the drive body 50 has a drive unit array, which includes a plurality of drive units 54 arranged on the same straight line at equal intervals p, except for a portion thereof.

[0105] By configuring it in this way, when using an inkjet head 100 of the line printhead type including multiple drive units 54, it is possible to improve the performance in the direction perpendicular to the printing direction. Figure 1 The printing resolution in the Y' direction (sub-scanning direction). This will be explained in detail later.

[0106] Furthermore, regarding the portion with a spacing of p', it is preferable that the width of the column portion 55 located between the drive portions 54 is different from the width of the other column portions 55. This allows the same cutting blade 59 to be used to process the portions of the drive portions 54 with different spacing.

[0107] Furthermore, the different spacing of the drive section 54 can also be formed by changing the thickness of the cutting blade 59, while keeping the width of the column section 55 the same. By making the width of the column section 55 the same, differences in the rigidity of the column section 55 can be prevented.

[0108] In addition, such as Figure 5B As shown, the column portion 55 may not be arranged between the drive portions 54, and the drive portions 54 may be arranged continuously along the Y direction. In this case, for example, 100 to 800 drive portions 54 are also arranged along the Y direction, most of these drive portions 54 are arranged at equal intervals with a spacing p, and at least a portion of them are arranged at a spacing p' different from the spacing p.

[0109] In this case, the drive body 50 also has a drive section array comprising a plurality of drive sections 54 arranged in the same straight line with equal intervals p except for a portion thereof.

[0110] Additionally, regarding the part with spacing p', and Figure 5A Similarly, in the case of the drive body 50 with column portion 55 shown, the width of the drive portion 54 arranged at a distance p' can be different from that of the other drive portions 54. Alternatively, the drive portions 54 can be arranged at a distance p' by changing the thickness of the cutting blade 59 and changing the width of the notch portion.

[0111] In addition, up to this point, the case where the drive unit 54 is a stacked piezoelectric element having multiple electrode layers 52, 53 has been described, but the structure of the drive unit 54 is not limited to this.

[0112] For example, the drive unit 54 can be a heating unit that heats the ink to make it expand and be ejected, a structure with a structure called a shared mode, or a structure that uses a thin-film PZT piezoelectric element.

[0113] In any configuration, the drive unit 54 functions to expel ink from the nozzle by compressing the ink. Hereinafter, the drive unit 54 will be described as being located at a point where a force is applied to the ink, either directly or via another component between the ink and the drive unit 54, to expel the ink from the nozzle 41.

[0114] Figure 6A This diagram illustrates the drive unit 54 in a thermal spraying process. In the case of thermal spraying, the ink 93 inside the pressure chamber 91 is compressed by the expansion force of the bubbles generated by heat, thereby ejecting the ink 93 from the nozzle 92. That is, the point of force that compresses the ink 93 is the heat source unit that generates heat, and the heat source unit is the drive unit 54.

[0115] Figure 6B This diagram illustrates the drive unit 54 in the shared mode configuration. In the shared mode configuration, the piezoelectric element 94 deforms, and ink 93 is clamped in from both sides and compressed, thereby ejecting the ink 93 from the nozzle. In this case, the midpoint of the line connecting the apex portions of each piezoelectric element 94 at the point of deformation becomes the drive unit 54. Furthermore, the ink 93 is ejected towards the front side of the paper surface.

[0116] Figure 6C This diagram illustrates the drive unit 54 in the venting mode. In the venting mode, the vertex portion of the piezoelectric element 95 during deformation becomes the drive unit 54. Furthermore, the piezoelectric element 95 can be constructed from a thin-film PZT element, or it can be constructed from a block PZT element as in this embodiment.

[0117] Furthermore, it is preferable that the drive unit 54 is positioned at the center of the pressure chamber 91 in the X direction. This is because if the deflection of the drive unit 54 and the vibrating plate 20 becomes uneven, the ejection may become unstable. On the other hand, in the Y direction, the drive unit 54 may be located at the center of the pressure chamber 91 or it may be located offset from the center. The configuration of the drive unit 54 can be designed with the balance of the configuration of the nozzle 92 and the pressure chamber 91 in mind.

[0118] Figure 6D This diagram illustrates the time-sharing injection control of the drive unit 54 in shared mode. In this time-sharing injection control, with... Figure 6D The two piezoelectric elements 94 corresponding to A, B, and C in the figure are compressed by clamping the ink from both sides in sequence, so that the ink 93 is ejected from the nozzle.

[0119] Even in this case, the situation remains unchanged: the drive unit 54 applies force to the ink directly or via other components between the ink and the drive unit 54, causing the ink to be ejected from the nozzle; therefore, the drive unit 54 is present in all channels.

[0120] Next, use Figure 7 This will explain the relationship between the inkjet head 100 and the drive units 110 and 111. Figure 7 This diagram illustrates the relationship between the inkjet head 100 and the drive units 110 and 111.

[0121] In this structure, two drive bodies 110 and 111 are configured for one inkjet head 100. Furthermore, each drive body 110 and 111 includes a drive section 54 of approximately 600 ch, most of which are arranged at a distance p along the Y direction, and at least a portion of which are arranged at a distance p'. Here, the drive section 54 arranged at a distance p' and the drive section 54 arranged at equal distance p are located on the same straight line.

[0122] Specifically, in the drive body 110, the drive section row 115 of the drive section 54 with approximately 300ch intervals p and the drive section row 116 of the drive section 54 with approximately 300ch intervals p are arranged on the same straight line.

[0123] Furthermore, the number of ch for each drive unit 54 can be any number, such as 300ch, 450ch, 900ch, or 1200ch, depending on the desired head size and nozzle spacing.

[0124] Furthermore, the distance between the drive unit 54 located on the drive unit 116 side of the drive unit included in the drive unit row 115 and the drive unit 54 located on the drive unit row 115 side of the drive unit 54 included in the drive unit row 116 is p'.

[0125] The inkjet head 100 configured in this way is arranged at an angle relative to the printing direction (X' direction), and the multiple inkjet heads 100 are arranged in parallel at fixed intervals along the Y' direction (sub-scanning direction) which is perpendicular to the X' direction.

[0126] Figure 8A This is a diagram illustrating the arrangement of the drive unit 54. Figure 8A This is a diagram of the drive body 110, which is formed by cutting and processing a piezoelectric element to create a drive section 54 and a column section 55, viewed from the +Z direction.

[0127] As described above, most of the drive units 54 are arranged with column units 55 sandwiched in the middle at equal intervals p. Near the center of the drive body 110, at least one part of the drive units 54 is provided with column units 55 of different widths sandwiched in the middle at a distance p' different from the distance p.

[0128] Figure 8B This diagram shows the positional relationship between the drive bodies 110 and 111 and the inkjet head 100. The inkjet head 100 has two drive bodies 110 and 111. In addition, the drive body 110 has a drive portion 54 and a pillar portion 55, and the drive body 111 has a drive portion 61 and a pillar portion 62.

[0129] The drive body 110 and drive body 111 are preferably configured such that the center of one of the drive portions 61 of the drive body 111 is located on the perpendicular bisector of the straight line connecting the center of one drive portion 54 of the drive body 110 and the center of another drive portion 54 adjacent to that drive portion 54.

[0130] Therefore, when using the inkjet heads 100 individually without arranging multiple inkjet heads side by side, most of the drive units 54 can be arranged at equal intervals in a direction perpendicular to the printing direction. Furthermore, the drive units 54 can be arranged at intervals of p / 2 along the Y direction. Although the portion with interval p' is not evenly spaced, its practical impact is minor.

[0131] Furthermore, row printheads, which arrange the inkjet heads 100 side by side, are mostly used in the mass production of large panels. On the other hand, in the early stages of mass production, for the purpose of performance verification and printing process condition debugging without considering the production cycle of the equipment, printing is sometimes carried out using the smallest possible inkjet head 100 to reduce costs. In addition, printing is sometimes carried out using small devices with one or a few inkjet heads 100.

[0132] For this reason, as shown below Figure 8D In that way, multiple inkjet heads 100 are basically arranged side by side for use, but they also have the advantage of being used individually.

[0133] In addition, the following explains why the effect of the portion with a spacing of p' is negligible in practical applications when verifying printing performance using a single or a few inkjet heads 100.

[0134] For example, in the case of manufacturing display panels by inkjet printing, it is important to drop ink onto the units of the display panel. In the case of manufacturing high-resolution display panels, printing is performed using an ejection channel with coordinates consistent with both, based on the control unit recognizing the unit position and the landing position of the ejection channel.

[0135] That is, it is not based on the premise of equally spaced ejection channels, but rather the ink is ejected at the same time as the ejection position data of each ejection channel is generated during printing. Therefore, even if the spacing p' is, for example, 4 / 5p, the practical impact is slight. On the other hand, if the spacing p' is a large value such as 3p, the software executed by the control unit cannot be fully corrected, resulting in non-ejection areas and hindering the verification of printing performance.

[0136] Furthermore, regarding the case of using the inkjet head 100 alone, when the long side of the inkjet head 100 is parallel to the Y' direction and multiple drive units 54 are arranged in the Y' direction for printing, the printing width can be maximized, so the inkjet head 100 is mostly used in this configuration.

[0137] In contrast, to improve nozzle resolution, the inkjet head 100 can be configured at an angle relative to the printing direction. That is, the inkjet head 100 can be rotated for alignment to match the nozzle spacing with the unit spacing, depending on the unit spacing of the printed object, and then the inkjet head 100 can be configured at an angle.

[0138] In both cases, there will be parts with a spacing of p' that are not equally spaced, but for the reasons mentioned above, the impact on practicality is minor.

[0139] Furthermore, considering factors such as uneven printing and printing cycle time, in a mass production apparatus for large panels, it is preferable to configure multiple inkjet heads to be arranged in parallel, with the drive units 54 arranged at equal intervals and the printing dots arranged at equal intervals in the Y' direction.

[0140] Figure 8C This diagram shows the case where the inkjet head 100 is configured at an angle relative to the printing direction. Additionally, Figure 8D This diagram shows a configuration where multiple inkjet heads 100 are arranged side by side.

[0141] like Figure 8D As shown, to make have Figure 8C Multiple inkjet heads 100a-100h of the drive bodies 110a-110h and 111a-111h shown are arranged side by side at an angle relative to the printing direction to form a row printhead. Therefore, for reasons explained later, the number of print dots (dpi) in the direction perpendicular to the printing direction can be increased, and high resolution can be achieved.

[0142] Next, the relationship between the configuration of the drive unit 54 and the printing resolution will be explained. Figure 9A This diagram illustrates the relationship between the configuration of the drive unit 54 and the printing resolution. Printing resolution refers to... Figure 1 The number of dots (dpi) printed by the inkjet head 100 in the Y' direction.

[0143] exist Figure 9A The diagram shows drive bodies 110 and 111 with drive sections 54 and 61 and column sections 55 and 62, lines α and β parallel to the Y-axis, and intersection points 130 to 133 of lines α and β with each drive section 54 and 61. Here, the positions of the intersection points 130 to 133 in the direction of lines α and β correspond to the center positions in the width direction of drive sections 54 and 61.

[0144] Intersection points 130 and 131 are arranged at equal intervals p on line α. If the shortest distance between intersection points 130 and 131 is set as D, then the interval p and the shortest distance D satisfy the following equation 1.

[0145] Here, constant m is an integer greater than or equal to 0, and constant n is a value calculated using the following formula 2 based on the number a of the drive bodies 110 and 111 in the inkjet head 100 and the total number b of the number of pitches p' that are different from the pitch p contained in each drive body 110 and 111. Constant i is a natural number smaller than constant n. Furthermore, constant n will be explained in detail later.

[0146] Similarly, intersection points 132 and 133 are arranged at equal intervals p on line β. If the shortest distance between intersection points 132 and 133 is set as D, then the shortest distance D satisfies Equation 1 and Equation 2 above.

[0147] In addition, Figure 9A In the example, the number a of the driving bodies 110 and 111 is 2, and the total number b of the number of spacings p' that are different from the spacing p contained in each driving body 110 and 111 is 1. Therefore, n = 2 × (1 + 1) = 4. Moreover, if m = 1 and i = 1, then the shortest distance D is (5 / 4)p.

[0148] Here, Figure 9A This is a conceptual diagram. For example, preferably, the spacing p is 50 μm or more and 200 μm or less, the shortest distance D is 300 μm or less, the multiple drive units of each inkjet head are arranged at an angle of 45 degrees or more and 80 degrees or less relative to the printing direction, and the number of inkjet heads is 20 or more and 120 or less.

[0149] In addition, although Figure 9A Not shown in the image, but formed in Figure 3 The protrusion 24 of the vibrating plate 20, the pressure chamber 33 of the flow path plate 30, and the nozzle 41 provided on the nozzle plate 40 are each provided on a straight line extending in the Z direction through the intersection points 130-133, corresponding to the intersection points 130-133 respectively. That is, a portion of the protrusion 24, the pressure chamber 33, and the nozzle 41 are penetrated by the straight line extending in the Z direction through the intersection points 130-133.

[0150] In particular, the landing position of the ink ejected from the inkjet head 100 is basically determined by the position of the nozzle 41, so a straight line passing through the intersection points 130-133 and extending in the Z direction needs to penetrate a portion of the nozzle 41. On the other hand, depending on the structure of the inkjet head 100, the protrusion 24 and the pressure chamber 33 are sometimes not connected.

[0151] In addition, the lines α and β can be located on the driving body 110 and the driving body 111 respectively, and their positions in the X direction are arbitrary.

[0152] In other words, the nozzle 41 can be located anywhere in the X direction, and the drive unit 54 can also be located anywhere in the X direction, but the nozzle 41 and the drive unit 54 are positioned in the Y direction. Therefore, the straight lines α and β only need to pass through the nozzle 41 at any position in the X direction, and must pass through a portion of the drive unit 54 that extends linearly along the X direction.

[0153] Next, the nozzle array used to achieve high-precision printing will be explained. Figure 9B This is a diagram illustrating the nozzle array used to achieve high-precision printing.

[0154] exist Figure 9B In this text, nozzle rows a~h containing nozzles 41 and nozzles 41 contained in each nozzle row a~h are designated as nozzles 130a~133a, 130b~133b. As described above, nozzles 130a~133a, 130b~133b are used... Figure 9A The intersection point obtained as described is located on a straight line extending along the Z direction.

[0155] In addition, Figure 9A In the middle, the position of the intersection points 130-133 is defined by the position of the center of the two straight lines α and β and the width direction of the drive parts 54 and 61, but... Figure 9B In this case, the position of the intersection point is determined by the position of the four straight lines α~δ parallel to the Y-axis and the center of the drive unit in the width direction.

[0156] like Figure 9B As shown, nozzles 130a and 131a are arranged on the same straight line α. Nozzles 132a and 133a are arranged on the same straight line β. Nozzles 130b and 131b are arranged on the same straight line γ. Nozzles 130b and 131b are arranged on the same straight line δ.

[0157] The nozzles 130a~133a and 130b~133b contained in each nozzle row a~h are arranged at equal intervals p.

[0158] Furthermore, when the shortest distance between the nozzle located on the side of nozzle group b in nozzle group a and the nozzle located on the side of nozzle group a in nozzle group b is set as D, the shortest distance D satisfies the aforementioned Equation 1. For example, in the case of m=1, i=1, n=4, D=(5 / 4)p.

[0159] Similarly, the shortest distance D between the nozzles in nozzle c located on the d side and the nozzles in nozzle d located on the c side, the shortest distance D between the nozzles in nozzle e located on the f side and the nozzles in nozzle f located on the e side, and the shortest distance D between the nozzles in nozzle g located on the h side and the nozzles in nozzle h located on the g side also satisfy the aforementioned Equation 1.

[0160] Next, the relationship between the positions of nozzles 130a, 130b, 131a, 131b and the positions of nozzles 132a, 132b, 133a, 133b will be explained. Nozzle 132a exists on a straight line ε that passes through the center point of the line connecting the positions of two adjacent nozzles 130a and extends along the X' direction. Furthermore, nozzle 132a exists on the perpendicular bisector of the straight line connecting the positions of two adjacent nozzles 130a.

[0161] Similarly, nozzle 132b exists on a straight line ζ that passes through the center point of the straight line connecting the positions of two adjacent nozzles 130b and extends along the X' direction. In addition, nozzle 132b exists on the perpendicular bisector of the straight line connecting the positions of two adjacent nozzles 130b.

[0162] Furthermore, nozzle 133a exists on a straight line η that passes through the center point of the straight line connecting the positions of two adjacent nozzles 131a and extends along the X' direction. Additionally, nozzle 133a exists on the perpendicular bisector of the straight line connecting the positions of two adjacent nozzles 131a.

[0163] Similarly, nozzle 133b exists on a straight line θ that passes through the center point of the straight line connecting the positions of two adjacent nozzles 131b and extends along the X' direction. In addition, nozzle 133b exists on the perpendicular bisector of the straight line connecting the positions of two adjacent nozzles 131b.

[0164] Furthermore, as described above, nozzles 132a, 132b, 133a, and 133b exist on the perpendicular bisector of the straight line connecting the positions of two adjacent nozzles 130a, 130b, 131a, and 131b. This allows for the equal arrangement of nozzle spacing in the Y' direction when the inkjet head 100 is used individually in a configuration parallel to the Y' direction.

[0165] However, in the inkjet head 100 that is configured to be tilted relative to the X' direction, it is also possible to configure it so that there are no nozzles 130a~133a, 130b~133b on the vertical bisector.

[0166] By configuring the nozzles 130a~133a and 130b~133b in this way, the nozzles 130a~133a and 130b~133b can be formed alternately at equal intervals in the Y' direction. By ejecting ink from such nozzles 130a~133a and 130b~133b, high-precision printing dots 134 can be achieved, thereby improving printing resolution.

[0167] Here, Figure 9BThe printed point 134 shown represents the intersection of a straight line extending along the X' direction through nozzles 130a~133a, 130b~133b and any straight line extending along the Y' direction. From the printed point 134, it can be seen that the printed points corresponding to each nozzle 130a~133a, 130b~133b are formed sequentially at equal intervals.

[0168] Thus, as shown in Equation 1 above, by setting the shortest distance D to a non-integer multiple of the spacing p, and setting the spacing of multiple nozzles in the Y' direction perpendicular to the printing direction to be equal, the printing resolution can be improved.

[0169] Furthermore, the inkjet unit 1 performs printing while moving the object to be printed 7 or the inkjet head 100 along the X' direction. At this time, the inkjet unit 1 controls the printing timing based on encoder information from the transport table 4, etc. Therefore, the positions of the nozzles 130a~133a and 130b~133b in the X' direction can be staggered. Importantly, the nozzles 130a~133a and 130b~133b are arranged at equal and narrow intervals in the Y' direction.

[0170] Next, Equations 1 and 2 above, which relate to the shortest distance D, will be explained in further detail. Additionally, for ease of explanation, the case of n=4 will be discussed below.

[0171] (1) Regarding the constant i The constant i can be any natural number smaller than the constant n. When n = 4, the constant i can be any value among 1, 2, and 3. The shortest distance D is set based on the value of the constant i.

[0172] When the constant i is set to 1 or 3, and Figure 9B Similarly, in the example shown, the distance between nozzle line a and nozzle line c can be determined by the structure in which the nozzle 132a contained in nozzle line c exists on a straight line extending in the X' direction through the center point of the straight line connecting the adjacent nozzles 130a contained in nozzle line a.

[0173] Thus, the nozzles 130a in nozzle column a and nozzles 132a in nozzle column c are staggered by 1 / 2 phase. When the constant i is 1 or 3, the nozzles 130a and 131a in nozzle columns a and b, and the nozzles 132a and 133a in nozzle columns c and d are staggered by 1 / 4 phase. Therefore, it is possible to set each column of nozzle columns a to d to be staggered by 1 / 4 phase. Furthermore, the definition of phase described in this embodiment will be explained later.

[0174] The same can be said for nozzle 133a in nozzle row d and adjacent nozzle 131a in nozzle row b, nozzle 132b in nozzle row g and adjacent nozzle 130b in nozzle row e, and nozzle 133b in nozzle row h and adjacent nozzle 131b in nozzle row f.

[0175] Furthermore, with the constant i set to 2, the distance between nozzle column a and nozzle column c can be determined by the structure in which the nozzle 132a contained in nozzle column c exists on a straight line extending in the X' direction, other than the center point of the point that is the point that is the center of the line that is the line that is the fourth to the point that is the adjacent nozzle 130a contained in nozzle column a.

[0176] Therefore, nozzle 130a in nozzle column a and nozzle 132a in nozzle column c are staggered by 1 / 4 phase. When the constant i is 2, each nozzle 130a and 131a in nozzle columns a and b, and each nozzle 132a and 133a in nozzle columns c and d are staggered by 1 / 2 phase. As a result, it is possible to set each column of nozzle columns a to d to be staggered by 1 / 4 phase.

[0177] In this case, the same can be said about the nozzle 133a included in nozzle row d and the adjacent nozzle 131a included in nozzle row b, the nozzle 132b included in nozzle row g and the adjacent nozzle 130b included in nozzle row e, and the nozzle 133b included in nozzle row h and the adjacent nozzle 131b included in nozzle row f.

[0178] (2) Regarding the spacing p The spacing p of nozzles 130a~133a and 130b~133b is, for example, 50μm or more and 200μm or less. However, the spacing p can be set arbitrarily, as long as it is appropriately determined according to the required printing resolution.

[0179] Although reducing the spacing p can improve printing resolution, reducing the spacing p can sometimes worsen crosstalk in the inkjet head 100, so this should also be taken into account when determining the appropriate spacing p.

[0180] (3) Regarding the constant m The constant m can be an integer greater than or equal to 0, but the constant m is preferably 0 or 1. This is because by minimizing the space where nozzles 130a~133a and 130b~133b are not present, the nozzle density in the inkjet head 100 can be increased. When the nozzle density is increased, the inkjet head 100 can also be miniaturized, or the arrangement width of the nozzles in the X' direction (i.e., the depth width of the printing area in the line printhead) can be reduced. This has the effects of suppressing uneven printing, miniaturizing the inkjet device 1, and reducing costs.

[0181] Furthermore, when using a single inkjet head 100 for the aforementioned applications, the impact on printing performance caused by the different spacing of nozzles 130a~133a and 130b~133b can be minimized.

[0182] Furthermore, by arranging multiple drive bodies and setting multiple drive columns on the same straight line on each drive body, when ink is ejected from the nozzle column corresponding to each drive column, if the shortest distance D becomes longer, for example, 3 to 10 mm, it becomes difficult to suppress uneven printing, miniaturize the inkjet device 1, reduce costs, and effectively utilize the inkjet device 1 in a single inkjet head 100.

[0183] Therefore, it is preferable that the shortest distance D between multiple drive units arranged on the same straight line is 300 μm or less. Moreover, in order to make the shortest distance D less than 300 μm, it is preferable that multiple drive units located directly above multiple nozzles in the Z direction are arranged in a single drive body.

[0184] In other words, for example, multiple nozzle rows a~h are used for... Figure 9B The arrangement of nozzles according to their positional relationships is preferred. At least two or more nozzle rows a to h arranged on the same straight line are preferably structures in which the force of ink ejection is applied by a single driving body, that is, part of the same driving body that applies displacement to the ink.

[0185] Here, the drive body has multiple drive units arranged on the same straight line. Each drive body has drive units arranged at equal intervals p. In two adjacent first drive units and second drive units arranged on the same straight line, the drive units in the first drive unit that are located on the side of the second drive unit and the drive units in the second drive unit that are located on the side of the first drive unit are arranged at a distance p' different from the distance p. This distance p' is equal to the shortest distance D calculated by Equation 1.

[0186] In addition, the smaller the shortest distance D is, the better. However, if the shortest distance D is too small, problems such as deterioration of machining accuracy and increased crosstalk will occur.

[0187] In view of these, the constant m is 0 or 1. When the constant n is 4, the shortest distance D is preferably 3 / 4p or more and 5 / 4p or less. Furthermore, when the constant n is 2, the shortest distance D is preferably 1 / 2p or more and 3 / 2p or less. In particular, when the constant m is 0, the constant i in Equation 1 above is preferably a value obtained by subtracting 1 from the constant n, or a value obtained by adding 1 to the constant n.

[0188] (4) Regarding the constant n The constant n is determined using Equation 2 based on the number a of driving elements that the inkjet head 100 has and the number b of pitches p' different from the pitch p in the driving elements. In other words, the constant n can be said to be the number of phases in the nozzle rows that the inkjet head 100 has.

[0189] Use Figure 9C And Figure 9D To explain the number of phases in this nozzle row. Figure 9C Is a diagram obtained by cutting out four nozzle rows a to d provided in the driving elements in the case where a plurality of inkjet heads 100 are arranged side by side as Figure 8D Shown. As Figure 9C Shown, in each of the nozzle rows a to d, each row is continuously formed without interruption in the Y' direction.

[0190] Figure 9D Is a diagram showing the positions in the Y' direction of the nozzles included in each of the nozzle rows a to d. As Figure 9D Shown, the nozzles included in the same nozzle rows a to d are arranged at equal pitches in the Y' direction. In addition, the nozzles included in each of the nozzle rows a to d are arranged in the Y' direction in the order of the nozzles included in nozzle row c, the nozzles included in nozzle row b, the nozzles included in nozzle row a, and the nozzles included in nozzle row d. In addition, the order of the nozzle rows a to d in which the nozzles are arranged in the Y' direction varies depending on the value of the above-mentioned constant i, the distance between the nozzle rows a to d, etc., and is not limited to Figure 9D The order shown but is arbitrary.

[0191] As described above, the nozzles included in the same nozzle rows a to d are continuously arranged at equal pitches in the Y' direction, and a state in which each nozzle included in the second nozzle row is arranged at the same position as each nozzle included in the first nozzle row in the Y' direction is defined as a state in which the second nozzle row is arranged in the same phase as the first nozzle row.

[0192] In addition, a state in which the positions of each nozzle included in the second nozzle row are offset by M / n (M is an integer satisfying M < n) of the pitch of the nozzles with respect to the positions of each nozzle included in the first nozzle row is defined as a state in which the second nozzle row is arranged with an offset of M / n phases with respect to the first nozzle row.

[0193] For example, in Figure 9D The nozzle rows shown, nozzle rows b and d are arranged with an offset of 1 / 4 phase from nozzle row a, and nozzle row c is arranged with an offset of 1 / 2 phase from nozzle row a.

[0194] Here, the number of nozzle rows with different phases among the multiple nozzle rows is 4, so in Figure 9DIn the example shown, the constant n is 4. Furthermore, since the drive unit and the nozzle are arranged in a one-to-one correspondence, the constant n can also be described as the number of drive unit rows with different phases among the multiple drive unit rows.

[0195] In addition, such as Figure 9C As shown, the nozzle rows a~d that form a phase need to be continuously formed without interruption in the Y' direction. That is, the nozzles contained in each nozzle row a~d need to be arranged at equal intervals in the Y' direction.

[0196] Therefore, the steeper the angle of nozzle arrays a~d, the narrower the nozzle spacing in the Y' direction, thus enabling high-resolution row nozzles. On the other hand, when the angle of nozzle arrays a~d is made steep, in order to continuously form nozzle arrays a~d in the Y' direction, it is necessary to make... Figure 9C The length of the nozzle columns a to d shown is increased, or the width of each nozzle column a to d is narrowed.

[0197] The width of the nozzle rows a~d is limited by the width of the inkjet head 100, so there is a limit to narrowing them. Basically, it is necessary to increase the row length, but this may lead to an expansion of the size of the inkjet head 100 and the printing width.

[0198] In contrast, by using the structure described in this embodiment, even if the nozzle rows a to d are lengthened to make the angle of the nozzle rows a to d steeper, the space where there are no nozzles in the Y direction can be reduced, and the four nozzle rows a to d are arranged in the Y' direction at equal intervals in sequence. Therefore, it is possible to achieve both improved nozzle resolution and miniaturization of the inkjet head 100.

[0199] In addition, Figure 9C as well as Figure 9D The description specifies that the number of phases in the nozzle arrangement of an inkjet head 100 is 4, but a number of phases of 2 or more is acceptable. The number of phases in an inkjet head 100 is determined by the product of the number of phases in a driver and the number of drivers, but these values ​​can be set arbitrarily.

[0200] (First variation) Next, a modified example of the structure of the drive body and drive unit will be described. Figure 10A This is a diagram showing a first modified example of the structure of the drive body and drive assembly.

[0201] In this structure, each inkjet head 100a~100d has a driver 110a~110d, and each driver 110a~110d has two driving segments 115a~115d and 116a~116d, with a phase number of 2.

[0202] Based on this structure, the width of the inkjet head 100a to 100d can be reduced. Furthermore, since the width of the same nozzle array can be reduced, the length of the nozzle array can be kept shorter when the tilt of the nozzle array is steepened.

[0203] (Second variation) A single inkjet head 100 can also have more than three actuators. Figure 10B This is a diagram showing a second variation of the structure of the drive body and drive assembly.

[0204] In this structure, each inkjet head 100a~100c has three drive bodies 110a~112a, 110b~112b, and 110c~112c, and each drive body 110a~112a, 110b~112b, and 110c~112c has two drive units 115a~115c and 116a~116c, with a phase number of 6.

[0205] In this structure, due to the increase in the number of phases, when the spacing between the nozzles in each nozzle row is p, the nozzles contained in each nozzle row can be arranged in the Y' direction with their positions staggered by p / 6.

[0206] In addition, in order to continuously arrange the nozzles at equal intervals in the Y' direction, it is necessary to lengthen the long side of the inkjet heads 100a~100c and their driving bodies 110a~112a, 110b~112b, 110c~112c, or to obtuse the tilt angle of the inkjet heads 100a~100c.

[0207] In particular, the length of the inkjet head 100 and its drive bodies 110a~112a, 110b~112b, 110c~112c in the long side direction is subject to manufacturing constraints, but if these constraints are met, the nozzle configuration density in the Y' direction can be increased.

[0208] (Third variation) Alternatively, an inkjet head can be constructed using a single driver with a phase number of 3 or more. Figure 10C This is a diagram showing a third variation of the structure of the drive body and drive assembly.

[0209] In this structure, each inkjet head 100a~100c has two drive bodies 110a~110c and 111a~111c, and each drive body 110a~110c and 111a~111c has three drive segments 115a~120a, 115b~120b and 115c~120c arranged in a straight line, with a phase number of 6.

[0210] In this structure, the number of phases is also increased, so that when the spacing between the nozzles in each nozzle row is p, the nozzles contained in each nozzle row can be arranged in the Y' direction with their positions staggered by p / 6.

[0211] In addition, similar to the second variation, in order to arrange the nozzles continuously at equal intervals in the Y' direction, it is necessary to lengthen the long side of the inkjet heads 100a~100c and their drive bodies 110a~110c, 111a~111c, or to make the tilt angle of the inkjet heads 100a~100c obtuse. However, if the aforementioned constraints are met, the nozzle arrangement density in the Y' direction can be increased.

[0212] (Fourth variation) A single driving unit can also have multiple driving units in the X direction. Figure 10D This is a diagram showing a fourth variation of the structure of the drive body and drive assembly.

[0213] In this structure, each inkjet head 100a and 100b has two drive bodies 110a, 111a, 110b, and 111b. Each drive body 110a, 111a, 110b, and 111b has four drive units 115a~118a, 115b~118b, 115c~118c, and 115d~118d. The number of phases in one drive body 110a, 111a, 110b, and 111b is 4, and the number of phases in each inkjet head 100a and 100b is 8.

[0214] Here, each of the four drive units 110a, 111a, 110b, and 111b has four drive units 115a~118a, 115b~118b, 115c~118c, and 115d~118d arranged in two on the same straight line to form a first drive unit and a second drive unit. The second drive unit is located at the position after the first drive unit has been moved parallel to the first drive unit in the X direction.

[0215] Even with this structure, it is possible to achieve both miniaturization of the inkjet head 100 and reduction of the depth and width of the printing area of ​​the line printhead, and to perform high-precision printing.

[0216] Figure 10E It means as Figure 10D The diagram shows an example of a nozzle array in which a single drive unit, such as the inkjet heads 100a and 100b, has multiple drive units in the X direction.

[0217] exist Figure 10EIn the diagram, a common circulation path 140a-140c is shown together with inkjet heads 100a and 100b. Additionally, inkjet heads 100a and 100b are shown to have separate circulation paths 141a and 141b, pressure chambers 142a and 142b, and nozzles 143a and 143b.

[0218] Ink flows into pressure chambers 142a and 142b via ink supply paths not shown in the diagram, and is ejected from nozzles 143a and 143b. Additionally, ink not ejected from nozzles 143a and 143b flows into common circulation paths 140a to 140c via separate circulation paths 141a and 141b.

[0219] In this structure, it is difficult to narrow the pitch p of the nozzle array, requiring approximately twice the pitch compared to the case with only one nozzle array in the X direction, thus resulting in a lower effect on increasing the nozzle density in the Y' direction. However, the ejection performance of the inkjet heads 100a and 100b can be improved due to reasons such as the ease of increasing the upper surface area of ​​the pressure chambers 142a and 142b.

[0220] Even in such a structure, by having the drive units included in the drive unit column arranged at equal intervals p in a single drive unit, and at least one of them arranged at a different interval p', it is possible to increase the nozzle density in the Y' direction while taking into account the miniaturization of the inkjet heads 100a and 100b.

[0221] (Fifth variation) In the case where a driving body has multiple driving units in the X direction, Figure 10D In the example, the phases of multiple drive units are different, but it is also possible to make the phases of multiple drive units the same. Figure 10F This is a diagram showing the fifth variation of the structure of the drive body and drive assembly.

[0222] In this structure, the inkjet head 100 has two drive bodies 110 and 111, and each drive body 110 and 111 has two drive segments 115a~118a and 115b~118b arranged in a straight line. In this case, the number of phases in one drive body 110 and 111 is 2, and the number of phases in one inkjet head 100 is 4.

[0223] Even with this structure, it can still achieve miniaturization of the inkjet head 100 and shorten the depth and width of the printing area of ​​the line printhead, while also enabling high-precision printing, thus playing a significant role in... Figure 7 The structure shown has the same effect. Additionally, with... Figure 10E Similarly, the ejection performance of the inkjet head 100 can be improved because it is easy to increase the upper surface area of ​​the pressure chamber.

[0224] (Sixth variation) In the case where a driving body has multiple driving units in the X direction, Figure 10D In the example, the phases of multiple drive units are different, but it is also possible to make the phases of multiple drive units the same. Figure 10G This is a diagram showing the sixth variation of the structure of the drive body and drive assembly.

[0225] In this structure, the inkjet head 100 has a driver 110, which has two drive columns 115-118 arranged in a straight line. Furthermore, drive columns 115 and 117 are in the same phase, and drive columns 116 and 118 are in the same phase. That is, in this case, the number of phases is 2.

[0226] (Inkjet head manufacturing process) To manufacture the inkjet head 100 of this embodiment, a longer drive unit is required compared to cases where multiple drive units are arranged in a straight line. Furthermore, for... Figure 2 When the drive body 50 shown is heated and joined with other components such as the vibrating plate 20 and flow path plate 30 that constitute the pressure chamber for storing ink, peeling may occur due to the difference in the coefficient of thermal expansion.

[0227] Therefore, it is preferable to use a low-temperature thermosetting adhesive that cures at a relatively low heating temperature, such as below 70 degrees Celsius, for heat bonding. In practice, a low-temperature thermosetting adhesive that cures at 60 degrees Celsius is used to bond the pre-bonded components, namely the vibrating plate 20, the flow path plate 30, and the nozzle plate 40, to the drive body 50.

[0228] In addition, when using a relatively long drive body 50, the warping of the drive body 50 itself can sometimes become a problem. Figure 11 This diagram illustrates how to deal with the warping of the drive body 50 itself.

[0229] like Figure 11 As shown, to address the warping of the drive body 50 itself, it is preferable to insert electrode layers 52 and 53 near the center of the drive body 50, and also insert dummy electrode layers 150a and 150b near the upper and lower end faces of the drive body 50 away from this location. Furthermore, the inserted dummy electrode layers 150a and 150b can be removed during processing before joining with other components, or they can be effectively utilized as GND electrode layers.

[0230] In addition, the manufacturing method of the nozzle also needs to be studied. For example, in the case of using laser to process nozzles, the method of forming multiple nozzles at the same time using a diffraction grating element called DOE (Diffractive Optical Element) is often used.

[0231] In this case, if processing is performed sequentially from the end side along the long side of the inkjet head 100, it becomes difficult to process portions having a spacing p' different from the spacing p of the drive section. Therefore, for example, when processing the second nozzle row on the same straight line as the first nozzle row, it is preferable to process sequentially starting from the nozzles closest to the first nozzle row.

[0232] In addition, the structure of the flow path section that allows ink to flow into or out of the inkjet head 100 can also be designed to achieve an effective configuration of the nozzle and the drive section.

[0233] Specifically, the number of connectors for allowing ink to flow into or out of the inkjet head 100 is preferably minimized. In practice, it is preferable to provide only one connector for allowing ink to flow into the inkjet head 100 and one connector for allowing ink to flow out of the inkjet head 100, with each connector located on the outside of all drive units.

[0234] For example, these connectors are configured in the Y direction at positions where the Y coordinate is greater than the Y coordinate value of all drive units, or at positions where the Y coordinate is smaller than the Y coordinate value of all drive units.

[0235] As explained above, the inkjet head structure described in this embodiment includes: a plurality of drive units arranged at a distance p; and a plurality of nozzles disposed at positions corresponding to the drive units, which eject ink by being driven by the drive units. The plurality of drive units have a first drive unit and a second drive unit arranged on the same straight line. The shortest distance D between the drive unit located on the second drive unit side of the first drive unit and the drive unit located on the first drive unit side of the second drive unit is a non-integer multiple of the distance p.

[0236] Therefore, when multiple inkjet heads 100 are arranged at an angle relative to the printing direction to form a line printhead, a line printhead with a high resolution such as 2,400 dpi can be achieved.

[0237] Furthermore, even when used at resolutions such as 600 to 1,200 dpi, the drive unit and nozzles can be arranged effectively, thus reducing the number of inkjet heads used, achieving an obtuse tilt angle, reducing costs, and minimizing printing unevenness.

[0238] According to the inkjet head, line printhead, inkjet device, and inkjet head manufacturing method disclosed herein, it is possible to achieve both miniaturization of the inkjet head and reduction of the depth and width in the printing area of ​​the line printhead, and to perform high-precision printing.

[0239] Industrial applicability This disclosure can be used for inkjet heads, line printheads, inkjet devices, and methods for manufacturing inkjet heads.

Claims

1. An inkjet head, have: Multiple drive units are arranged in rows, with a spacing p between them; and Multiple nozzles are configured at positions corresponding to the drive unit, and ink is ejected by the drive unit. The plurality of drive units have a first drive unit and a second drive unit arranged on the same straight line, wherein the shortest distance D between the drive unit located on the side of the second drive unit in the first drive unit and the drive unit located on the side of the first drive unit in the second drive unit is a non-integer multiple of the spacing p.

2. The inkjet head according to claim 1, The first drive unit and the second drive unit are part of the same drive body that imparts displacement to the ink.

3. The inkjet head according to claim 1, The shortest distance D is an integer multiple of the value obtained by dividing the spacing p by a constant n, where the constant n is the number of drive units with different phases among the plurality of drive units.

4. The inkjet head according to claim 1, When the constant m is set to an integer greater than or equal to 0, the constant n is set to the number of drive units with different phases among the plurality of drive units, and the constant i is set to a natural number smaller than the constant n, the following conditions apply. The shortest distance D is (m + i / n)p.

5. The inkjet head according to claim 1, The plurality of drive units have a third drive unit and a fourth drive unit arranged on the same straight line parallel to the same straight line. The first drive unit and the second drive unit are part of a first drive body. The third drive unit and the fourth drive unit are part of a second drive body that is different from the first drive body. The first drive body and the second drive body each have 2 phases, and the total number of phases is 4.

6. The inkjet head according to claim 4, The constant m is 0, and the constant i is the value obtained by subtracting 1 from the constant n, or by adding 1 to the constant n.

7. The inkjet head according to claim 1, Regarding the driving units included in the first driving unit column of one of the two adjacent driving unit columns arranged in parallel among the plurality of driving unit columns, the driving units are located on the perpendicular bisector of the line connecting the adjacent driving units included in the first driving unit column of the other driving unit column, and regarding the driving units included in the second driving unit column of the one driving unit column, the driving units are located on the perpendicular bisector of the line connecting the adjacent driving units included in the second driving unit column of the other driving unit column.

8. The inkjet head according to claim 1, The plurality of driving units are arranged between adjacent driving units and have non-driving units. The driving units are piezoelectric elements with an electrode layer to which a voltage is applied, and the non-driving units are piezoelectric elements with an electrode layer to which no voltage is applied.

9. A row-type sprinkler head, It has multiple inkjet heads as described in claim 1.

10. The row nozzle according to claim 9, The spacing p is 50 μm or more and 200 μm or less, the shortest distance D is 300 μm or less, the plurality of drive units are arranged at an angle of 45° or more and 80° or less relative to the printing direction, and the number of inkjet heads is 20 or more and 120 or less.

11. An inkjet device, have: The row nozzle as described in claim 9; A conveyor table that holds the printed object to be coated with the ink; and A drive device causes the row nozzle to move relative to the conveyor table.

12. A method for manufacturing an inkjet head, as described in claim 1. The drive unit and the component constituting the pressure chamber for storing the ink are joined together by sandwiching them with a thermosetting adhesive that cures at a temperature below 70 degrees Celsius. The thermosetting adhesive is thermosetting at a temperature below 70 degrees Celsius.

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