Liquid nozzle and liquid ejection device

Abstract

This invention provides a liquid ejector head and a liquid ejector device that reduce ink viscosity while achieving cost reduction in the liquid ejection device. The liquid ejector head has: multiple individual flow channels with nozzles; a common supply flow channel that supplies liquid to the multiple individual flow channels; a common discharge flow channel that discharges liquid from the multiple individual flow channels; and a bypass flow channel that bypasses the multiple individual flow channels and connects the common supply flow channel and the common discharge flow channel. The combined flow channel resistance of the bypass flow channel and the multiple individual flow channels is larger than the flow channel resistance of the common supply flow channel and larger than the flow channel resistance of the common discharge flow channel.

Description

Technical Field

[0001] This invention relates to a liquid ejector head and a liquid ejection device. Background Technology

[0002] In liquid ejection devices, such as inkjet printers, there are cases where a structure exists that circulates the liquid within a liquid ejection head that ejects liquids such as ink, as disclosed in Patent Documents 1 and 2.

[0003] Patent Document 1 describes a head having multiple pressure generating chambers communicating with nozzle openings, a first manifold and a second manifold communicating with the multiple pressure generating chambers, and a bypass channel connecting these manifolds using a system other than the pressure generating chambers. Here, ink is supplied from the ink cartridge in the first manifold by the driving force of a pump. The ink circulates from the first manifold through the pressure generating chambers or the bypass channel into the second manifold and then returns to the ink cartridge. In Patent Document 1, when the flow resistance of the bypass channel is set to R, the flow resistance of the channel connecting the two manifolds, including the pressure generating chambers, is set to r, and the number of nozzle openings is set to N, R < r / N is satisfied.

[0004] Patent Document 2 describes a head having multiple pressure chambers connected to a nozzle, a supply-side common flow channel for storing liquid supplied to the pressure chambers via a liquid supply channel, a circulation-side common flow channel for storing liquid recovered from the pressure chambers via a liquid circulation channel, and a bypass flow channel for allowing liquid to flow from the supply-side common flow channel to the circulation-side common flow channel. Here, when the flow resistance of the bypass flow channel is set to R, the number of pressure chambers is set to N, and the flow resistance from the liquid supply channel through the pressure chambers to the liquid circulation channel is set to r, the relationship r / N < R < r is satisfied.

[0005] In the structures described in Patent Documents 1 and 2 mentioned above, there is a problem that it is impossible to reduce the viscosity of the ink while achieving cost reduction.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2013-184372

[0007] Patent Document 2: Japanese Patent Application Publication No. 2010-214847 Summary of the Invention

[0008] To address the above-mentioned issues, the preferred embodiment of the present invention relates to a liquid ejector head comprising: a plurality of individual flow channels provided with nozzles; a common supply flow channel supplying liquid to the plurality of individual flow channels; a common discharge flow channel discharging liquid from the plurality of individual flow channels; and a bypass flow channel that bypasses the plurality of individual flow channels and connects the common supply flow channel with the common discharge flow channel; wherein the combined flow channel resistance of the bypass flow channel and the plurality of individual flow channels is greater than the flow channel resistance of the common supply flow channel and greater than the flow channel resistance of the common discharge flow channel.

[0009] The liquid ejection device according to a preferred embodiment of the present invention includes: a liquid ejection head as described above; and a control unit that controls the liquid ejection action performed by the liquid ejection head. Attached Figure Description

[0010] Figure 1 This is a schematic diagram illustrating a structural example of the liquid ejection device according to the embodiment.

[0011] Figure 2 This is a perspective view of a liquid ejection module having the liquid ejection head according to the embodiment.

[0012] Figure 3 for Figure 2 An exploded perspective view of the liquid ejector head shown.

[0013] Figure 4 A top view schematically illustrating the flow channel of the head body of a liquid ejector head.

[0014] Figure 5 This is a cross-sectional view of the head body of a liquid ejector head.

[0015] Figure 6 This is a top view of the support frame.

[0016] Figure 7 A perspective view showing the flow channel and head body mounted on the support.

[0017] Figure 8 for Figure 6 Sectional view along line AA in the diagram.

[0018] Figure 9 This is a top view of the flow channel structure.

[0019] Figure 10 for Figure 9 BB line section view.

[0020] Figure 11 The equivalent circuit diagram is shown for the flow channel set in the liquid nozzle.

[0021] Figure 12 This is a flowchart illustrating an example of the operation of the liquid ejection device according to an embodiment. Detailed Implementation

[0022] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the dimensions and scales of the various parts in the drawings differ appropriately from actual dimensions, and some parts are shown schematically for ease of understanding. Furthermore, unless otherwise specified in the following description, the scope of the present invention is not limited to these embodiments.

[0023] For ease of explanation, the following description will appropriately use intersecting X-axis, Y-axis, and Z-axis. Furthermore, one direction along the X-axis is the X1 direction, and the direction opposite to the X1 direction is the X2 direction. The X1 or X2 direction is an example of a "second direction." Similarly, opposite directions along the Y-axis are the Y1 and Y2 directions. The Y1 or Y2 direction is an example of a "third direction." Furthermore, opposite directions along the Z-axis are the Z1 and Z2 directions. The Z1 or Z2 direction is an example of a "first direction."

[0024] Here, typically, the Z-axis is a vertical axis, and the Z2 direction corresponds to the downward direction in the vertical direction. However, the Z-axis may not be a vertical axis, and it may be inclined relative to the vertical axis. Furthermore, although the X-axis, Y-axis, and Z-axis are typically orthogonal to each other, this is not a limitation; for example, they may intersect at an angle between 80° and 100°. Additionally, the "second direction" only needs to be a direction orthogonal to the Z-axis, and may be, for example, the Y1 or Y2 direction. The "third direction" only needs to be orthogonal to both the "first direction" and the "second direction," for example, if the "second direction" is the Y1 or Y2 direction, the "third direction" may be the X1 or X2 direction.

[0025] 1. Implementation Method

[0026] 1-1. Liquid ejection device 100

[0027] Figure 1 This is a schematic diagram illustrating a structural example of the liquid ejection apparatus 100 according to the embodiment. The liquid ejection apparatus 100 is an inkjet printing apparatus that ejects ink, an example of a liquid, as droplets onto a medium M. The liquid ejection apparatus 100 of this embodiment is a so-called row-type printing apparatus in which multiple nozzles for ejecting ink are distributed across the entire width direction of the medium M. The medium M is typically printing paper. However, the medium M is not limited to printing paper; for example, it can be any printing material such as resin film or fabric.

[0028] like Figure 1 As shown, the liquid ejection device 100 includes a liquid container 110, a control unit 120 (as an example of a "control unit"), a conveying mechanism 130, a liquid ejection module 140, and a circulation mechanism 150.

[0029] Liquid container 110 is a container for storing ink. Examples of specific types of liquid container 110 include ink cartridges that are detachable from the liquid dispensing device 100, ink pouches formed of a flexible film, and ink cans capable of being refilled. Furthermore, the type of ink stored in liquid container 110 can be any type.

[0030] Although not illustrated, the liquid container 110 of this embodiment includes a first liquid container and a second liquid container. A first ink is stored in the first liquid container. A second ink of a different type than the first ink is stored in the second liquid container. For example, the first ink and the second ink may be inks of different colors. Alternatively, the first ink and the second ink may be inks of the same type.

[0031] The control unit 120 controls the operation of various elements of the liquid dispensing device 100. The control unit 120 includes, for example, one or more processing circuits such as a CPU (Central Processing Unit) or FPGA (Field Programmable Gate Array), and one or more storage circuits such as semiconductor memory. Various programs and data are stored in the storage circuits. The processing circuits execute the programs and appropriately use the data to achieve various controls.

[0032] The conveying mechanism 130 conveys the medium M in the direction DM based on control implemented by the control unit 120. In this embodiment, the direction DM is the Y2 direction. Figure 1 In the example shown, the conveying mechanism 130 includes a conveying roller that is elongated along the X-axis and a motor that rotates the conveying roller. Furthermore, the conveying mechanism 130 is not limited to a structure using a conveying roller; for example, it can also be a structure using a roller or a seamless belt to convey the medium M in a state where the medium M is adsorbed onto the outer peripheral surface by electrostatic force or the like.

[0033] The liquid ejection module 140, based on control implemented by the control unit 120, ejects ink supplied from the liquid container 110 via the circulation mechanism 150 from each of a plurality of nozzles along the Z2 direction onto the medium M. The liquid ejection module 140 is a row head having a plurality of liquid ejection heads 10, which are configured such that the nozzles span the entire range of the medium M in the X-axis direction. That is, the assembly of the plurality of liquid ejection heads 10 constitutes an elongated row head extending in the X-axis direction. The ejection of ink from the plurality of liquid ejection heads 10 is performed in parallel with the transport of the medium M implemented by the transport mechanism 130, thereby forming an ink-generated image on the surface of the medium M. Alternatively, it may be configured such that the plurality of nozzles of a single liquid ejection head 10 span the entire range of the medium M in the X-axis direction, in which case, for example, the liquid ejection module 140 is constituted by that single liquid ejection head 10.

[0034] A liquid container 110 is connected to the liquid ejection module 140 via a circulation mechanism 150. The circulation mechanism 150 is a mechanism that supplies ink to the liquid ejection module 140 based on control implemented by the control unit 120, and recycles ink discharged from the liquid ejection module 140 back to the liquid ejection module 140. The circulation mechanism 150 includes, for example, a secondary tank for storing ink, a supply channel for supplying ink from the secondary tank to the liquid ejection module 140, a recovery channel for recovering ink from the liquid ejection module back to the secondary tank, and a pump for properly circulating the ink. These circulation mechanisms are provided for each of the first and second liquid containers described above. Through the operation of the circulation mechanism 150, the increase in ink viscosity can be suppressed, or the retention of air bubbles within the ink can be reduced.

[0035] 1-2. Liquid ejection module 140

[0036] Figure 2 This is a perspective view of a liquid ejection module 140 having the liquid ejection head 10 according to the embodiment. Figure 2 As shown, the liquid ejection module 140 has a support body 41 and a plurality of liquid ejection heads 10. The support body 41 is a component that supports the plurality of liquid ejection heads 10. Figure 2 In the example shown, the support 41 is a plate-shaped component made of metal or the like, and it has mounting holes 41a for mounting a plurality of liquid nozzles 10. The plurality of liquid nozzles 10 are inserted into the mounting holes 41a in a configuration along the X-axis, and each liquid nozzle 10 is fixed to the support 41 by screws or the like. Figure 2The diagram illustrates two liquid nozzles 10. The number of liquid nozzles 10 in the liquid ejection module 140 is arbitrary. Furthermore, the shape of the support 41 is not limited to any particular type. Figure 2 The example shown is not for any shape.

[0037] 1-3. Liquid ejector head 10

[0038] Figure 3 for Figure 2 An exploded perspective view of the liquid ejector head 10 shown. Figure 3 As shown, the liquid ejector head 10 includes a flow channel structure 11, a wiring board 12, a support 13, multiple head bodies 14_1, 14_2, 14_3, 14_4, 14_5, and 14_6, a fixing plate 15, and a base 16. These components are arranged in the Z2 direction in the following order: base 16, flow channel structure 11, wiring board 12, support 13, multiple head bodies 14_1, 14_2, 14_3, 14_4, 14_5, and 14_6, and fixing plate 15. The various parts of the liquid ejector head 10 will be described in turn below. In the following text, each of the head bodies 14_1, 14_2, 14_3, 14_4, 14_5, and 14_6 will sometimes be referred to as head body 14.

[0039] The flow channel structure 11 is a structure with internally provided flow channels for allowing ink to flow between the circulation mechanism 150 and the multiple head bodies 14. For example... Figure 3 As shown, the flow channel structure 11 is provided with connecting pipes 11a, 11b, 11c, 11d and holes 11e.

[0040] Here, although Figure 3 While the diagram is omitted, the flow channel structure 11 contains a first supply flow channel, a second supply flow channel, a first discharge flow channel, and a second discharge flow channel. The first supply flow channel supplies first ink to the multiple head bodies 14. The second supply flow channel supplies second ink to the multiple head bodies 14. Filters for capturing foreign objects are provided midway through each of these supply flow channels. The first discharge flow channel discharges the first ink from the multiple head bodies 14. The second discharge flow channel discharges the second ink from the multiple head bodies 14. Furthermore, the flow channels of the flow channel structure 11 will be discussed based on the description below. Figure 9 as well as Figure 10 Let me explain.

[0041] Connecting tubes 11a, 11b, 11c, and 11d are tubes protruding in the Z1 direction. More specifically, connecting tube 11a forms a channel for supplying the first ink to the first supply channel. Connecting tube 11b forms a channel for supplying the second ink to the second supply channel. Connecting tube 11c forms a channel for discharging the first ink from the first discharge channel. Connecting tube 11d forms a channel for discharging the second ink from the second discharge channel. Hole 11e is a hole for inserting the connector 12c, described later. Flexible hoses connected to the outside are respectively connected to connecting tubes 11a, 11b, 11c, and 11d. Liquid is supplied from the outside into the liquid nozzle 10 via connecting tubes 11a and 11b. Liquid is discharged from the inside of the liquid nozzle 10 to the outside via connecting tubes 11c and 11d.

[0042] The wiring board 12 is a mounting component for electrically connecting multiple head bodies 14 to the assembly board 16b described later. The wiring board 12 is, for example, a rigid wiring board. The wiring board 12 is disposed between the flow channel structure 11 and the support 13, and a connector 12c is provided on the surface of the wiring board 12 opposite to the flow channel structure 11. The connector 12c is a connecting component that connects to the assembly board 16b described later. Furthermore, the wiring board 12 has multiple holes 12a and multiple openings 12b. Each hole 12a is a hole for allowing connection between the flow channel structure 11 and the support 13. Each opening 12b is a hole through which a wiring board 14h, for connecting the head body 14 to the wiring board 12, passes. This wiring board 14h is connected to the surface of the wiring board 12 facing the Z1 direction. The wiring substrate 14h is a component that includes wiring electrically connected to the piezoelectric element 14e described below, such as an FPC (Flexible Printed Circuits) or COF (Chip On Film).

[0043] The bracket 13 is a structure that houses and supports multiple head bodies 14. The bracket 13 is made of, for example, resin or metal. The bracket 13 is plate-shaped and extends in a direction perpendicular to the Z-axis. Furthermore, the bracket 13 is provided with connecting pipes 13a, 13b, multiple connecting pipes 13c, multiple connecting pipes 13d, and multiple wiring holes 13e. Additionally, although not shown, multiple recesses for housing the multiple head bodies 14 are provided on the Z2-facing surface of the bracket 13.

[0044] In this embodiment, six head bodies 14_1 to 14_6 are held on the support 13. These head bodies are arranged in the X2 direction in the order of head bodies 14_1, 14_4, 14_2, 14_5, 14_3, and 14_6. Here, head bodies 14_1 to 14_3 are positioned offset from head bodies 14_4 to 14_6 in the Y1 direction. However, head bodies 14_1 to 14_6 have overlapping portions when viewed in the X1 or X2 direction. Furthermore, the arrangement directions DN of the plurality of nozzles N of head bodies 14_1 to 14_6, which will be described later, are parallel to each other. In addition, each of head bodies 14_1 to 14_6 is arranged such that its arrangement direction DN is inclined relative to the direction DM, which is the conveying direction of the medium M.

[0045] Here, although Figure 3 The diagram is omitted, but the support 13 contains a first distribution supply channel, a second distribution supply channel, multiple first individual discharge channels, multiple second individual discharge channels, and multiple bypass channels. The first distribution supply channel has branches for supplying first ink to multiple head bodies 14. The second distribution supply channel has branches for supplying second ink to multiple head bodies 14. The first individual discharge channel is provided for each head body 14 discharging first ink and is used to introduce the first ink discharged from the head body 14 into the first discharge channel of the channel structure 11. The second individual discharge channel is provided for each head body 14 discharging second ink and is used to introduce the second ink discharged from the head body 14 into the second discharge channel of the channel structure 11. The bypass channels are two for each head body 14, connecting the first common liquid chamber R1 and the second common liquid chamber R2 described later. Regarding the channels of the support 13, the following will be based on... Figures 6 to 8 Let me explain.

[0046] In this embodiment, a first ink is supplied to head bodies 14_1 to 14_3 among head bodies 14_1 to 14_6, and a second ink is supplied to head bodies 14_4 to 14_6.

[0047] Connecting pipes 13a, 13b, 13c, and 13d are tubular protrusions extending in the Z1 direction. More specifically, connecting pipe 13a is a pipe body that forms a channel for supplying the first ink to the first dispensing supply channel and communicates with the first supply channel of the channel structure 11. Furthermore, connecting pipe 13b is a pipe body that forms a channel for supplying the second ink to the second dispensing supply channel and communicates with the second supply channel of the channel structure 11. On the other hand, connecting pipe 13c is a pipe body that forms a channel for discharging the first ink from the first separate discharge channel and communicates with the first discharge channel of the channel structure 11. Furthermore, connecting pipe 13d is a pipe body that forms a channel for discharging the second ink from the second separate discharge channel and communicates with the second discharge channel of the channel structure 11. Wiring hole 13e is a hole through which the wiring substrate 14h, through which the connector body 14 connects to the wiring substrate 12, passes.

[0048] Each head body 14 ejects ink. Specifically, although in Figure 3 The illustrations are omitted, but each head body 14 has multiple nozzles for ejecting a first ink and multiple nozzles for ejecting a second ink. These nozzles are disposed on the Z2-oriented surface of each head body 14, i.e., the nozzle surface FN. Detailed information about the head body 14 will be provided later. Figure 4 Let me explain.

[0049] The fixing plate 15 is a plate component used to fix a plurality of head bodies 14 to the bracket 13. Specifically, the fixing plate 15 is configured to sandwich a plurality of head bodies 14 between itself and the bracket 13, and is fixed to the bracket 13 by adhesive. The fixing plate 15 is made of, for example, a metal material. A plurality of openings 15a are provided on the fixing plate 15 to expose the nozzles of the plurality of head bodies 14. Figure 3 In the example shown, the plurality of openings 15a are provided individually for each head body 14. Alternatively, the openings 15a may also be in a form shared by two or more head bodies 14.

[0050] The base 16 is a component used to fix the flow channel structure 11, wiring board 12, bracket 13, multiple head bodies 14, and fixing plate 15 onto the support 41 described above. The base 16 has a body 16a, a collection board 16b, and a cover 16c.

[0051] The main body 16a is fixed to the bracket 13 by means of screws or the like, thereby holding the flow channel structure 11 and the wiring board 12 disposed between the base 16 and the bracket 13. The main body 16a is made of, for example, resin material. The main body 16a has a plate-shaped portion opposite to the plate-shaped portion of the flow channel structure 11 described above, and a plurality of holes 16d are provided on the plate-shaped portion for insertion of the connecting pipes 11a, 11b, 11c and 11d described above. In addition, the main body 16a has a portion extending in the Z2 direction from the plate-shaped portion, and a flange 16e for fixing to the support body 41 described above is provided at the top end of the portion.

[0052] The mounting base 16b is a mounting component for electrically connecting the control unit 120 to the aforementioned wiring base 12. The mounting base 16b is, for example, a rigid wiring base. The cover 16c is a plate-shaped component for protecting the mounting base 16b and fixing it to the main body 16a. The cover 16c is made of, for example, resin material and is fixed to the main body 16a by screws or the like.

[0053] 1-4. Head body 14

[0054] Figure 4 This is a top view schematically illustrating the flow channel of the head body 14 of the liquid ejector head 10. For ease of explanation, the following description will use the V-axis and W-axis appropriately in addition to the X-axis, Y-axis, and Z-axis. Furthermore, one direction along the V-axis is the V1 direction, and the direction opposite to the V1 direction is the V2 direction. Similarly, the opposite directions along the W-axis are the W1 direction and the W2 direction.

[0055] Here, the V-axis is the axis along the arrangement direction of the plurality of nozzles N, as described later, and is the axis after the Y-axis has been rotated about the Z-axis by a predetermined angle. The W-axis is the axis after the X-axis has been rotated about the Z-axis by the predetermined angle. Therefore, although the V-axis and W-axis are typically orthogonal to each other, they are not limited to this; for example, they may intersect at an angle in the range of 80° to 100°. Furthermore, this predetermined angle, i.e., the angle between the V-axis and the Y-axis, or the angle between the W-axis and the X-axis, is, for example, in the range of 40° to 60°.

[0056] like Figure 4 As shown, the head body 14 is provided with multiple nozzles N, multiple individual flow channels P, a first common liquid chamber R1, and a second common liquid chamber R2. Here, the first common liquid chamber R1 and the second common liquid chamber R2 are connected via multiple individual flow channels P. Furthermore, as shown by... Figure 4As shown by the double-dotted lines, bypass channels BP1 and BP2 are connected to the first common liquid chamber R1 and the second common liquid chamber R2. Bypass channels BP1 and BP2 are channels that bypass multiple individual channels P and connect the first common liquid chamber R1 and the second common liquid chamber R2, and they are mounted on the support 13. Detailed information about bypass channels BP1 and BP2 will be provided later. Figure 6 , Figure 7 as well as Figure 8 Let me explain.

[0057] The head body 14 has a surface opposite to the medium M, on which, for example Figure 4 As shown, multiple nozzles N are arranged. The multiple nozzles N are arranged along the V-axis. The multiple nozzles N eject ink in the Z2 direction.

[0058] Here, a collection of multiple nozzles N constitutes a nozzle array Ln. Furthermore, the multiple nozzles N are arranged at predetermined intervals. This predetermined interval is the distance between the centers of the multiple nozzles N along the V-axis.

[0059] Each of the multiple nozzles N is connected to a separate flow channel P. Each of the multiple flow channels P extends along the W-axis and connects to a different nozzle N. The multiple flow channels P are arranged along the V-axis.

[0060] like Figure 4 As shown, each individual flow channel P has a pressure chamber Ca, a pressure chamber Cb, a nozzle flow channel Nf, a separate supply flow channel Ra1, a separate discharge flow channel Ra2, a first connecting flow channel Na1, and a second connecting flow channel Na2.

[0061] The pressure chambers Ca and Cb of each individual flow channel P are spaces extending along the W axis and storing ink ejected from the nozzle N connected to that individual flow channel P. Figure 4 In the example shown, multiple pressure chambers Ca are arranged along the V-axis. Similarly, multiple pressure chambers Cb are arranged along the V-axis. Furthermore, in each individual flow channel P, although the positions of the pressure chambers Ca and Cb along the V-axis are... Figure 4 The examples shown are identical, but they can also be different. Furthermore, in the following text, unless a specific distinction is made between pressure chamber Ca and pressure chamber Cb, they will sometimes be referred to as "pressure chamber C".

[0062] A nozzle flow channel Nf is disposed between the pressure chambers Ca and Cb of each individual flow channel P. Here, pressure chamber Ca is connected to nozzle flow channel Nf via a first connecting flow channel Na1 extending along the Z-axis. Pressure chamber Cb is connected to nozzle flow channel Nf via a second connecting flow channel Na2 extending along the Z-axis.

[0063] In each individual flow channel P, the nozzle flow channel Nf is a space extending along the W axis. Furthermore, multiple nozzle flow channels Nf are arranged along the V axis at intervals between each other. A nozzle N is provided in each nozzle flow channel Nf. In each nozzle flow channel Nf, ink is ejected from the nozzle N by changing the pressure within the pressure chambers Ca and Cb described above.

[0064] The first connecting channel Na1 and the second connecting channel Na2 are spaces extending along the Z-axis. Furthermore, the first connecting channel Na1 and the second connecting channel Na2 can be set only as needed and can also be omitted.

[0065] A first common liquid chamber R1 and a second common liquid chamber R2 are connected through multiple individual flow channels P. Here, pressure chamber Ca is connected to the first common liquid chamber R1 via a separate supply flow channel Ra1 extending along the Z-axis. Pressure chamber Cb is connected to the second common liquid chamber R2 via a separate discharge flow channel Ra2 extending along the Z-axis.

[0066] The first common liquid chamber R1 and the second common liquid chamber R2 are spaces extending along the V-axis, spanning the entire area distributed across the multiple nozzles N. The first common liquid chamber R1 is connected to one end of each individual flow channel P in the W2 direction. The first common liquid chamber R1 stores ink for supplying to each individual flow channel P. On the other hand, the second common liquid chamber R2 is connected to one end of each individual flow channel P in the W1 direction. The second common liquid chamber R2 stores ink that is not used for ejection but is discharged from each individual flow channel P.

[0067] The first common liquid chamber R1 is provided with a supply port IO1, a discharge port IO3a, and a discharge port IO3b. The supply port IO1 is a conduit for introducing ink from the distribution supply channel SP of the support 13 into the first common liquid chamber R1. The discharge port IO3a is a conduit for discharging ink from the first common liquid chamber R1 into the bypass channel BP1. The discharge port IO3b is a conduit for discharging ink from the first common liquid chamber R1 into the bypass channel BP2. Furthermore, the distribution supply channel SP is either the first distribution supply channel SP1 or the second distribution supply channel SP2, as described later.

[0068] Here, the supply channel SP is connected to the circulation mechanism 150 via the supply channel CC of the channel structure 11. Therefore, the channel from the connecting pipe 11a or connecting pipe 11b to the first common liquid chamber R1 is provided in a shared manner for multiple pressure chambers C, forming a common supply channel CF1 that supplies ink to multiple individual channels P. Furthermore, the supply channel CC is either the first supply channel CC1 or the second supply channel CC2, as described later. Additionally, although in Figure 4Although not illustrated, the common supply channel CF1 includes, in addition to the first common liquid chamber R1, the distribution supply channel SP, and the supply channel CC, either the first filter chamber RF1 or the second filter chamber RF2, as described later. More specifically, the common supply channel CF1 refers to the channel constituting the liquid nozzle 10, extending immediately after the portion (connecting pipe 11a, connecting pipe 11b) connected to the hose for supplying liquid from the outside of the liquid nozzle 10, and immediately before the individual channel P. That is, the supply channel CF1 is the channel extending from the first filter chamber RF1, the second filter chamber RF2, to the first common liquid chamber R1.

[0069] The second common liquid chamber R2 is provided with a discharge port IO2, an inlet IO4a, and an inlet IO4b. Discharge port IO2 is a conduit for discharging ink from the second common liquid chamber R2 to the separate discharge channel DS of the support 13. Inlet IO4a is a conduit for introducing ink from the bypass channel BP1 to the second common liquid chamber R2. Inlet IO4b is a conduit for introducing ink from the bypass channel BP2 to the second common liquid chamber R2. Furthermore, the separate discharge channel DS is either the first separate discharge channel DS1 or the second separate discharge channel DS2, as described later.

[0070] Here, the individual discharge channel DS is connected to the circulation mechanism 150 via the discharge channel CM of the channel structure 11. Therefore, the channel from the second common liquid chamber R2 to the connecting pipe 11a or connecting pipe 11b is provided in a common form for multiple pressure chambers C, and forms a common discharge channel CF2 for discharging ink from multiple individual channels P. In addition, the discharge channel CM is either the first discharge channel CM1 or the second discharge channel CM2 described later. The common discharge channel CF2 refers to the path of the components constituting the liquid nozzle 10 from immediately following the individual channel P to immediately preceding the portion (connecting pipe 11c, connecting pipe 11d) connected to the hose for discharging liquid to the outside of the liquid nozzle 10.

[0071] Figure 5 This is a cross-sectional view of the head body 14 of the liquid ejection head 10. Figure 5 The image shows a cross-section of the head body 14, which is cut by planes including the W-axis and Z-axis. (See image for details.) Figure 5 As shown, the head body 14 has a nozzle substrate 14a, a flow channel substrate 14b, a pressure chamber substrate 14c, a vibrating plate 14d, multiple piezoelectric elements 14e, a housing 14f, a protective plate 14g, and a wiring substrate 14h.

[0072] The nozzle substrate 14a, flow channel substrate 14b, pressure chamber substrate 14c, and vibrating plate 14d are laminated in the Z1 direction in this order. These components extend along the V-axis and are manufactured, for example, by processing a single-crystal silicon substrate using semiconductor processing techniques. Furthermore, these components are bonded together by adhesives or the like. Alternatively, other layers or substrates, such as adhesive layers, may be appropriately placed between adjacent components.

[0073] A plurality of nozzles N are provided on the nozzle substrate 14a. Each nozzle N is a through hole that penetrates the nozzle substrate 14a to allow ink to pass through. The plurality of nozzles N are arranged in a direction along the V-axis.

[0074] A portion of each of the first common liquid chamber R1 and the second common liquid chamber R2, and portions of a plurality of individual flow channels P excluding pressure chambers Ca and Cb are provided on the flow channel substrate 14b. That is, a nozzle flow channel Nf, a first connecting flow channel Na1, a second connecting flow channel Na2, an individual supply flow channel Ra1, and an individual discharge flow channel Ra2 are provided on the flow channel substrate 14b.

[0075] A portion of each of the first common liquid chamber R1 and the second common liquid chamber R2 forms a space penetrating the flow channel substrate 14b. On the Z2-oriented surface of the flow channel substrate 14b, a vibration absorber 14j is provided to close the opening formed by the space.

[0076] The vibration absorber 14j is a layered component made of elastic material. The vibration absorber 14j forms part of the wall of the first common liquid chamber R1 and the second common liquid chamber R2, and absorbs pressure fluctuations in the first common liquid chamber R1 and the second common liquid chamber R2.

[0077] The nozzle channel Nf is a space provided in a groove on the surface of the channel substrate 14b facing the Z2 direction. Here, the nozzle substrate 14a constitutes part of the wall surface of the nozzle channel Nf.

[0078] The first connecting channel Na1 and the second connecting channel Na2 are spaces that penetrate the channel substrate 14b.

[0079] Separate supply channel Ra1 and separate discharge channel Ra2 are spaces penetrating the flow channel substrate 14b. Separate supply channel Ra1 connects the first common liquid chamber R1 to the pressure chamber Ca, supplying ink from the first common liquid chamber R1 to the pressure chamber Ca. One end of separate supply channel Ra1 opens on the Z1-oriented surface of the flow channel substrate 14b. The other end of separate supply channel Ra1 is the upstream end of separate channel P and opens on the wall of the first common liquid chamber R1 of the flow channel substrate 14b. Conversely, separate discharge channel Ra2 connects the second common liquid chamber R2 to the pressure chamber Cb, discharging ink from the pressure chamber Cb to the second common liquid chamber R2. One end of separate discharge channel Ra2 opens on the Z1-oriented surface of the flow channel substrate 14b. The other end of separate discharge channel Ra2 is the downstream end of separate channel P and opens on the wall of the second common liquid chamber R2 of the flow channel substrate 14b.

[0080] Pressure chambers Ca and Cb, each with a separate flow channel P, are provided on the pressure chamber substrate 14c. Pressure chambers Ca and Cb penetrate the pressure chamber substrate 14c and are respectively the gaps between the flow channel substrate 14b and the vibrating plate 14d.

[0081] The vibrating plate 14d is a plate-shaped component capable of elastic vibration. The vibrating plate 14d is, for example, a laminate comprising a first layer of silicon oxide (SiO2) and a second layer of zirconium oxide (ZrO2). Alternatively, other layers such as metal oxides may be interposed between the first and second layers. Furthermore, part or all of the vibrating plate 14d may be integrally formed from the same material as the pressure chamber substrate 14c. For example, by selectively removing a portion of the plate-shaped component of a predetermined thickness in the thickness direction from the region corresponding to the pressure chamber C, the vibrating plate 14d and the pressure chamber substrate 14c can be integrally formed. Furthermore, the vibrating plate 14d may also be composed of a single layer of material.

[0082] On the Z1-oriented surface of the vibrating plate 14d, a plurality of piezoelectric elements 14e, each corresponding to a different pressure chamber C, are provided. Each piezoelectric element 14e is constructed, for example, by laminating a first electrode and a second electrode facing each other, and a piezoelectric layer disposed between the two electrodes. Each piezoelectric element 14e causes the ink in the pressure chamber C to be ejected from the nozzle N by changing the pressure of the ink in the pressure chamber C. The piezoelectric element 14e is supplied with a drive signal Com, which causes the vibrating plate 14d to vibrate along with its own deformation. The pressure chamber C expands and contracts with this vibration, thereby changing the pressure of the ink in the pressure chamber C.

[0083] The housing 14f is a housing for storing ink. On the housing 14f, spaces are respectively provided that constitute the remaining portion of the first common liquid chamber R1 and the second common liquid chamber R2, excluding the portion provided on the flow channel substrate 14b.

[0084] The protective plate 14g is a plate-shaped component disposed on the Z1-oriented surface of the vibrating plate 14d. It protects the multiple piezoelectric elements 14e and strengthens the mechanical strength of the vibrating plate 14d. Here, a space is formed between the protective plate 14g and the vibrating plate 14d to house the multiple piezoelectric elements 14e.

[0085] The wiring board 14h is mounted on the Z1-oriented surface of the vibrating plate 14d and serves as a mounting component for electrically connecting the control unit 120 and the head body 14. For example, a flexible wiring board 14h, such as an FPC (Flexible Printed Circuit) or FFC (Flexible Flat Cable), is preferably used. The aforementioned drive circuit 14i is mounted on the wiring board 14h.

[0086] In the head body 14 of the above structure, the operation of the circulation mechanism 150 described above causes the ink to flow in the first common liquid chamber R1, the individual supply channel Ra1, the pressure chamber Ca, the nozzle channel Nf, the pressure chamber Cb, the individual discharge channel Ra2, and the second common liquid chamber R2 in this order.

[0087] Furthermore, by utilizing the drive signal Com from the drive circuit 14i, the piezoelectric elements 14e corresponding to both pressure chambers Ca and Cb are simultaneously driven, thereby causing pressure changes in pressure chambers Ca and Cb, and ink is ejected from nozzle N along with these pressure changes. Regarding the operation of the circulation mechanism 150, it will be based on the description below. Figure 12 Let me explain.

[0088] 1-5. Bracket 13

[0089] Figure 6 This is a top view of bracket 13. Figure 7 This is a perspective view showing the flow channel and head body 14 mounted on the support 13. Additionally, in Figure 6 In the image, a dashed line illustrates an example of the structure within the support 13 when viewed in the Z2 direction. Figure 7 In addition to showing the flow channel of the bracket 13 and multiple head bodies 14, the mounting plate 15 is also shown.

[0090] like Figure 6 as well as Figure 7As shown, the bracket 13 is provided with a first distribution supply channel SP1, a second distribution supply channel SP2, three first separate discharge channels DS1, three second separate discharge channels DS2, six bypass channels BP1 and six bypass channels BP2.

[0091] The first distribution supply channel SP1 has three branching sections for supplying the first ink introduced into the connecting tube 13a to the three head bodies 14. The second distribution supply channel SP2 has three branching sections for supplying the second ink introduced into the connecting tube 13b to the three head bodies 14.

[0092] The first separate discharge channel DS1 is provided for each head body 14 using the first ink and is used to discharge the first ink introduced from the head body 14 through the connecting pipe 13c. The second separate discharge channel DS2 is provided for each head body 14 using the second ink and is used to discharge the second ink introduced from the head body 14 through the connecting pipe 13d.

[0093] Bypass channels BP1 and BP2 are respectively provided for each head body 14 and connect the aforementioned first common liquid chamber R1 and second common liquid chamber R2. However, bypass channels BP1 and BP2 are located on opposite sides of the center of the first common liquid chamber R1 or the second common liquid chamber R2 along the X-axis. Figure 6 In the example shown, bypass channel BP1 is located in the V2 direction relative to bypass channel BP2. Furthermore, both bypass channels BP1 and BP2 are U-shaped when viewed along the Z-axis.

[0094] Figure 8 for Figure 6 A sectional view along line AA. Figure 8 In addition to the bracket 13, the diagram also shows the head body 14 and the fixing plate 15. Figure 8 As shown, the support 13 is plate-shaped, extending in a direction perpendicular to the Z-axis. The support 13 has layers 31 and 32, which are laminated in the Z2 direction in this order. Layers 31 and 32 are made of resin material, for example, and are formed by injection molding. Layers 31 and 32 are bonded together, for example, by an adhesive.

[0095] The laminate composed of layers 31 and 32 has the aforementioned flow channels of the support 13, and a recess 13f for accommodating the head body 14 is provided on the Z2-oriented surface of layer 32. Figure 8In the example shown, the thickness of layer 32 is greater than that of layer 31. Therefore, the thickness of layer 32 required for the formation of recess 13f can be easily ensured.

[0096] Here, the first distribution supply channel SP1 has a longitudinal channel SP1 and a transverse channel SP1. The longitudinal channel SP1 extends along the Z-axis and is formed by a hole penetrating layer 32. The transverse channel SP1 extends in a direction orthogonal to the Z-axis and is disposed between layer 31 and layer 32. Figure 8 In the example shown, the crossflow channel SPb is composed of grooves provided on the surface of layer 31 facing the Z2 direction and grooves provided on the surface of layer 32 facing the Z1 direction. Furthermore, although in Figure 8 Although not illustrated, the second distribution supply channel SP2 is constructed in the same manner as the first distribution supply channel SP1.

[0097] The bypass channel BP1 has a first portion BP1a, a second portion BP1b, and a third portion BP1c. The first portion BP1a and the second portion BP1b extend along the Z-axis and are formed by holes penetrating layer 32. The third portion BP1c extends in a direction orthogonal to the Z-axis and is disposed between layer 31 and layer 32. Figure 8 In the example shown, the third part BP1c is composed of a groove provided on the surface of layer 31 facing the Z2 direction and a groove provided on the surface of layer 32 facing the Z1 direction.

[0098] Similarly, the bypass channel BP2 has a first portion BP2a, a second portion BP2b, and a third portion BP2c. The first portion BP2a and the second portion BP2b extend along the Z-axis and are formed by holes penetrating layer 32. The third portion BP2c extends in a direction orthogonal to the Z-axis and is disposed between layer 31 and layer 32. Figure 8 In the example shown, the third part BP2c is composed of a groove provided on the surface of layer 31 facing the Z2 direction and a groove provided on the surface of layer 32 facing the Z1 direction.

[0099] 1-6. Flow channel structure 11

[0100] Figure 9 This is a top view of the flow channel structure 11. Figure 9 In the image, a dashed line illustrates an example of the structure within the flow channel structure 11 when viewed in the Z2 direction. (See image for details.) Figure 9 As shown, a first supply channel CC1, a second supply channel CC2, a first discharge channel CM1, a second discharge channel CM2, a first filter chamber RF1, and a second filter chamber RF2 are provided inside the flow channel structure 11.

[0101] The first supply channel CC1 is a channel for supplying the first ink, which is introduced into the connecting tube 11a, to the aforementioned support 13. Here, the first supply channel CC1 communicates with the internal space of the connecting tube 11a via the first filter chamber RF1. An outlet CE1, which is connected to the aforementioned connecting tube 13a, is connected to the first supply channel CC1.

[0102] The second supply channel CC2 is used to supply the second ink introduced into the connecting tube 11b via the aforementioned support 13. Here, the second supply channel CC2 communicates with the internal space of the connecting tube 11b via the second filter chamber RF2. An outlet CE2, connected to the aforementioned connecting tube 13b, is connected to the second supply channel CC2.

[0103] The first discharge channel CM1 is for discharging the first ink from the aforementioned support 13 from the connecting tube 11c. An inlet CI1, which is connected to the three connecting tubes 13c mentioned above, is connected to the first discharge channel CM1.

[0104] The second discharge channel CM2 is for discharging the second ink from the aforementioned support 13 from the connecting tube 11d. An inlet CI2, which is connected to the three connecting tubes 13d mentioned above, is connected to the second discharge channel CM2.

[0105] Figure 10 for Figure 9 A sectional view along the BB line. Figure 10 In the diagram, a representative structure corresponding to the connecting pipe 11a is shown for the flow channel structure 11. The structure corresponding to the connecting pipe 11b is the same as the structure corresponding to the connecting pipe 11a.

[0106] like Figure 10 As shown, the flow channel structure 11 is plate-shaped and extends in a direction perpendicular to the Z-axis. The flow channel structure 11 has layers 21, 22 and 23, a fixing component 24 between layers 21 and 22, and a filter 25.

[0107] Layers 21, 22, and 23 are laminated in this order along the Z2 direction. Layers 21, 22, and 23 are made of resin material, for example, and are formed by injection molding. Layers 21, 22, and 23 are bonded together, for example, by an adhesive. Furthermore, the thicknesses of layers 21, 22, and 23 along the Z-axis can be the same or different from each other.

[0108] A concave surface 21a, an inlet 21b, and a groove 21c are provided on layer 21. The concave surface 21a is provided on the surface of layer 21 facing the Z2 direction and forms part of the wall of the first filter chamber RF1. Figure 10In the example shown, the concave surface 21a has a shape that continuously deepens towards the inlet 21b. The inlet 21b is a through hole that opens into the concave surface 21a and communicates with the internal space of the connecting pipe 11a. Figure 10 In the example shown, the connecting tube 11a and the layer 21 are integrally formed. Therefore, the connecting tube 11a and the layer 21 are both made of resin material. The groove 21c is provided along the outer periphery of the concave surface 21a on the surface of the layer 21 facing the Z2 direction, and forms a space for receiving a part of the fixing member 24 described later. The groove 21c can also function as a recess for the adhesive.

[0109] Alternatively, the connecting tube 11a can be separately constructed from the layer 21. In this case, the connecting tube 11a can also be made of a metal material or the like and fixed to the layer 21 by an adhesive or the like. Furthermore, the groove 21c can be provided only as needed and can also be omitted. In addition, similar to the connecting tube 11a, the connecting tubes 11b to 11c can be integrally constructed with the layer 21 or separately constructed from the layer 21.

[0110] A recess 22a, a groove 22b, a hole 22c, and a hole 22d are provided on layer 22. The recess 22a is provided on the surface of layer 22 facing the Z1 direction and forms a space for receiving a portion of the fixing member 24 described later. The groove 22b is provided on the surface of layer 22 facing the Z2 direction and forms a portion of the first supply channel CC1. Figure 10 In the example shown, the first supply channel CC1 is shaped as a portion extending along the Y-axis and narrowing towards the Y2 direction, with an area in the XZ plane. Holes 22c and 22d are openings in the recess 22a and trench 22b, respectively, and penetrate layer 22. Figure 10 In the example shown, hole 22c is connected to one end of groove 22b in the Y2 direction. Hole 22d is connected to groove 22b at a position relative to hole 22c in the Y1 direction.

[0111] A groove 23a is provided on layer 23. The groove 23a is provided on the surface of layer 23 facing the Z1 direction and forms part of the first supply channel CC1. Figure 10 In the example shown, groove 23a has a shape that extends along the Y-axis. Additionally, although in Figure 10 In the example shown, the first supply channel CC1 is formed by the trench 22b of layer 22 and the trench 23a of layer 23, but the first supply channel CC1 can also be formed by either the trench 22b or the trench 23a.

[0112] The fixing component 24 is a generally plate-shaped component that fixes the filter 25 to at least one of the layers 21 and 22 and forms part of the wall of the first filter chamber RF1. Figure 10 In the example shown, the fixing member 24 is disposed on the recess 22a described above. The fixing member 24 is made of, for example, resin material and is formed by injection molding. Here, by using insert molding with the filter 25 as an insert, the fixing member 24 is formed, thereby fixing the filter 25 to the fixing member 24. Furthermore, the fixing member 24 is fixed to at least one of layer 21 and layer 22, for example, by adhesive.

[0113] Thus, by fixing the filter 25 to at least one of layers 21 and 22 via the fixing member 24, compared to a structure where the filter 25 is directly fixed to at least one of layers 21 and 22, the range of choices for the structural materials of layers 21 and 22 can be expanded, or the situation where adhesive is unintentionally adhered to the filter 25 can be reduced. Furthermore, the material of the fixing member 24 can be the same as or different from the material of layers 21 or 22.

[0114] The fixed component 24 is provided with a bottom wall 24a, a frame 24b, a first outlet 24c, and a second outlet 24d.

[0115] The bottom wall 24a is disposed on the surface of the fixed component facing the Z1 direction and forms part of the wall of the first filter chamber RF1. Figure 10 In the example shown, the bottom wall 24a has a shape that continuously deepens towards the first outlet 24c and the second outlet 24d, respectively. The frame portion 24b is an annular wall portion along the outer periphery of the bottom wall 24a and constitutes the sidewall of the first filter chamber RF1. More specifically, a portion of the inner peripheral surface of the frame portion 24b constitutes the sidewall 24i of the downstream chamber RFb. Figure 10 In the example shown, a portion of the frame portion 24b is inserted into the groove 21c described above. This insertion positions the fixing member 24 relative to the layer 21. Furthermore, a gap is formed between the outer peripheral surface of the frame portion 24b and the recess 22a. This gap functions as a receptacle for the adhesive. The first outlet 24c and the second outlet 24d are holes that open into the bottom wall 24a and penetrate the fixing member 24. The first outlet 24c connects to the hole 22c described above and together with the hole 22c forms a first flow channel C1. The second outlet 24d connects to the hole 22d described above and together with the hole 22d forms a second flow channel C2.

[0116] The filter 25 is a plate-shaped or sheet-shaped component that allows ink to pass through and captures foreign matter mixed in with the ink. The filter 25 is constructed, for example, of metal fibers in a diagonal or flat weave. However, the filter 25 is not limited to a structure using metal fibers; it may also be constructed of resin fibers such as non-woven fabric. The filter 25 is typically arranged parallel to the nozzle surface FN. However, the filter 25 may also be configured to be inclined relative to the nozzle surface FN at an angle of 0 degrees or more but less than 45 degrees.

[0117] The filter 25 is fixed to the frame portion 24b of the aforementioned fixing member 24. Here, the first filter chamber RF1 is divided into an upstream chamber RFa and a downstream chamber RFb by the filter 25. The upstream chamber RFa is a space located in the Z1 direction relative to the filter 25, with the concave surface 21a as part of the wall. The downstream chamber RFb is a space located in the Z2 direction relative to the filter 25, with the side wall 24i and the bottom wall 24a as part of the wall.

[0118] Figure 11 The equivalent circuit diagram is shown for the flow channel disposed on the liquid ejector head 10. Figure 11 The diagram shows the flow resistance of each part of the flow channel.

[0119] As described above, the liquid ejector head 10 has multiple individual flow channels P, a common supply flow channel CF1, a common discharge flow channel CF2, and bypass flow channels BP1 and BP2. Nozzles N are respectively provided on the multiple individual flow channels P. The common supply flow channel CF1 supplies ink, as an example of "liquid," to the multiple individual flow channels P. The common discharge flow channel CF2 discharges the ink from the multiple individual flow channels P. The bypass flow channels BP1 and BP2 bypass the multiple individual flow channels P and connect the common supply flow channel CF1 and the common discharge flow channel CF2.

[0120] Here, the combined flow resistance Rs of the bypass channels BP1, BP2, and multiple individual channels P is larger than the flow resistance Rin of the common supply channel CF1 and larger than the flow resistance Rout of the common discharge channel CF2. The effects obtained by establishing such a relationship between the combined flow resistance Rs, the flow resistance Rin, and the flow resistance Rout will be explained below.

[0121] In the liquid ejector head 10, although the image quality can be improved by arranging the nozzles N in a high density, this also requires that the individual flow channels P also be made in a high density. Therefore, in order to improve the image quality, the cross-sectional area of ​​the individual flow channels P must be reduced. If it is assumed that bypass flow channels BP1 and BP2 are not provided in the liquid ejector head 10, the liquid will not be able to circulate sufficiently, and thus the viscosity of the ink cannot be properly eliminated.

[0122] In contrast, by providing bypass channels BP1 and BP2 in the liquid ejector head 10 and reducing the flow resistance RBP of the bypass channels BP1 and BP2, the combined flow resistance Rs of the multiple individual channels P and the bypass channels BP1 and BP2 is also reduced. Therefore, if the overall flow rate of the ink circulated by the circulation mechanism 150 is increased to some extent, the elimination of ink viscosity can be optimized. Furthermore, the flow resistance RBP is the combined flow resistance of the bypass channels BP1 and BP2.

[0123] However, if only ink viscosity reduction is prioritized and the flow resistance RBP of bypass channels BP1 and BP2 is made too small, the combined flow resistance Rs of the multiple individual channels P and bypass channels BP1 and BP2 will become less than the flow resistance Rin of the common supply channel CF1 or the flow resistance Rout of the common discharge channel CF2. Consequently, the flow resistance within the liquid nozzle 10 will be determined by the flow resistance Rin of the common supply channel CF1 or the flow resistance Rout of the common discharge channel CF2. On the other hand, the common supply channel CF1 and the common discharge channel CF2 are connected to multiple individual channels P in a shared manner. Therefore, generally, each of the common supply channel CF1 and the common discharge channel CF2 needs to increase its flow rate to some extent, thus necessitating an increase in cross-sectional area. This, in turn, causes the flow resistances Rin and Rout to decrease to some extent. As mentioned above, when the flow resistance RBP of the bypass channels BP1 and BP2 is too small, the flow resistances Rin and Rout become the decisive factors in the flow resistance of the channels within the liquid nozzle 10. Therefore, reducing the flow resistances Rin or Rout results in the disadvantage that the amount of ink circulated by the circulation mechanism 150 increases, thus requiring an increase in the capacity of the pumps used in the circulation mechanism 150 or an increase in the number of pumps.

[0124] On the other hand, despite the difficulties mentioned above, if the flow channel resistance Rin and the flow channel resistance Rout can be increased respectively, the ink circulation flow rate itself achieved by the circulation mechanism 150 can be reduced. However, since this obviously reduces the amount of ink flowing in the individual flow channel P, the effect of eliminating ink viscosity cannot be properly obtained.

[0125] Therefore, in the liquid ejector head 10, the flow resistance of the bypass channels BP1 and BP2 is adjusted such that the combined flow resistance Rs, which is the flow resistance of the combined flow channel consisting of bypass channels BP1 and BP2 and multiple individual channels P, is greater than each of the flow resistance Rin of the common supply channel CF1 and the flow resistance Rout of the common discharge channel CF2. In this way, since the flow resistance of the bypass channels BP1 and BP2 is adjusted, it is not necessary to significantly increase the overall ink circulation flow rate achieved by the circulation mechanism 150, thus eliminating the need to increase the capacity of the pump used in the circulation mechanism 150 or increase the number of pumps. Furthermore, since it is not necessary to significantly reduce the flow rate in the individual channels P, the effect of ink viscosity reduction can also be appropriately obtained.

[0126] Preferably, the combined flow channel resistance Rs of the bypass channels BP1, BP2 and the multiple individual channels P is 50% to 70% less than the combined flow channel resistance Rall of the bypass channels BP1, BP2, the multiple individual channels P, the common supply channel CF1 and the common discharge channel CF2, which is the overall flow channel resistance of the liquid nozzle 10. As mentioned above, when the combined flow channel resistance Rs, which is the flow channel resistance of the combined flow channel composed of the bypass channels BP1, BP2 and the multiple individual channels P, is greater than each of the flow channel resistance Rin of the common supply channel CF1 and the flow channel resistance Rout of the common discharge channel CF2, if we study it in units of 1%, the minimum and maximum values ​​of the combined flow channel resistance Rs will be as described below. The minimum value of the combined flow channel resistance Rs is 34% of the combined flow channel resistance Rall (the flow channel resistances of the common supply channel CF1 and the common discharge channel CF2 are 33% respectively). Furthermore, the maximum value of the combined flow channel resistance Rs is 98% of the combined flow channel resistance Rall (the flow channel resistances of the common supply flow channel CF1 and the common discharge flow channel CF2 are each 1%). That is, the effects of the present invention can be obtained when the combined flow channel resistance Rs is 34% or more and 98% or less of the combined flow channel resistance Rall. However, in reality, in the overall flow channel of the liquid ejector head 10, if the common supply flow channel CF1 or the common discharge flow channel CF2 becomes the decisive factor for ink flow, even if the flow channel resistances of the multiple individual flow channels P and the bypass flow channels BP1 and BP2 are adjusted as in each embodiment, it may not be possible to properly control the overall ink flow rate. Therefore, it is preferable to make the combined flow channel resistance of the common supply flow channel CF1 and the common discharge flow channel CF2 less than 50% of the combined flow channel resistance Rall, in other words, to set the combined flow channel resistance Rs to be 50% or more of the combined flow channel resistance Rall. On the other hand, if the combined flow channel resistance Rs is too large, the flow rate of ink flowing through the multiple individual flow channels P and the bypass flow channels BP1, BP2 will be extremely limited. As a result, it may be impossible to sufficiently eliminate ink viscosity depending on the type of ink. Specifically, if the combined flow channel resistance Rs is 70% or less of the combined flow channel resistance Rall, ink viscosity can be appropriately eliminated in various inks. That is, although it is necessary in the present invention for the combined flow channel resistance Rs to be 34% or more and 98% or less relative to the combined flow channel resistance Rall, it is particularly preferred to be 50% or more and 70% or less. This effect resulting from setting it to 50% or more and 70% or less can be obtained in Examples 2, 3, 4, 5, 6, 12, 13, 14, and 15 of the various embodiments in Table 1 described below. These embodiments correspond to the examples marked "A" in the "Other" column shown in Table 1.

[0127] Furthermore, preferably, the flow resistance RBP of the bypass channels BP1 and BP2 is smaller than the combined flow resistance RP of the multiple individual channels P. More preferably, the flow resistance RBP of the bypass channels BP1 and BP2 is 25% or more and 55% or less of the combined flow resistance RP of the multiple individual channels P. If the flow resistance RBP of the bypass channels BP1 and BP2 is too small compared to the combined flow resistance RP of the multiple individual channels P, there is a possibility that too much ink flows in the bypass channels BP1 and BP2 compared to the individual channels P, thus requiring an increase in the overall flow rate to remove air bubbles mixed into the individual channels P. On the other hand, if the flow resistance RBP of the bypass channels BP1 and BP2 is too large compared to the combined flow resistance RP of the multiple individual channels P, the flow resistance of the individual channels P will be relatively smaller, thus increasing the cross-sectional area of ​​the individual channels P to some extent and decreasing the density of the nozzles N, potentially resulting in unsatisfactory image quality. To appropriately balance the high density of nozzles N and the reduction of the overall flow rate of ink circulated through the circulation mechanism 150, it is preferable that the flow resistance RBP of the bypass channels BP1 and BP2 is less than the combined flow resistance RP of the multiple individual channels P. This effect can be obtained in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 13, 14, and 15 of the various embodiments described in Table 1 below. These embodiments correspond to the examples marked "B" in the "Others" column of Table 1. Furthermore, to more appropriately balance the high density of nozzles N and the reduction of the overall flow rate of ink circulated through the circulation mechanism 150, it is more preferable that the flow resistance RBP of the bypass channels BP1 and BP2 is set to be 25% or more and 55% or less relative to the combined flow resistance RP of the multiple individual channels P. This effect can be obtained in Examples 2, 3, 4, 5, 6, 7, 12, 13, 14, and 15 of the various embodiments described in Table 1 below. These examples correspond to the examples listed under "C" in the "Other" column of Table 1.

[0128] As mentioned above, each of the plurality of individual flow channels P includes a pressure chamber C for applying pressure to eject ink from the nozzle N, a separate supply flow channel Ra1 for supplying ink to the pressure chamber C, and a separate discharge flow channel Ra2 for discharging ink from the pressure chamber C.

[0129] Preferably, the flow resistance RBP of the bypass channels BP1 and BP2 is smaller than the combined flow resistance RCa of the individual supply channels Ra1 included in the plurality of individual channels P. In this case, the overall flow rate of ink circulated through the circulation mechanism 150 can be appropriately reduced.

[0130] Furthermore, preferably, the flow resistance RBP of the bypass channels BP1 and BP2 is smaller than the combined flow resistance RCb of the multiple individual discharge channels Ra2. In this case, the overall flow rate of ink circulated through the circulation mechanism 150 can be appropriately reduced.

[0131] The effect achieved by making the flow resistance RBP of the bypass channels BP1 and BP2 less than the combined flow resistance RCa of the multiple individual supply channels Ra1 and the combined flow resistance RCb of the multiple individual discharge channels Ra2 can be obtained in Examples 1, 2, 3, 4, 5, 6, 7, 12, 13, 14, and 15 of the embodiments described below in Table 1. These embodiments correspond to the examples marked "D" in the "Other" column of Table 1.

[0132] Furthermore, preferably, the flow resistance of each individual supply channel Ra1 included in the plurality of individual flow channels P is approximately equal to the flow resistance of each individual discharge channel Ra2 included in the plurality of individual flow channels P. If the flow resistances of the individual supply channel Ra1 and the individual discharge channel Ra2 are different, even if the piezoelectric element 14e is driven in the same manner, the flow (momentum) of the liquid will differ in the pressure chambers Ca and Cb before reaching the nozzle. Therefore, it may be necessary to adjust the driving of the piezoelectric element 14e to be unequal in the pressure chambers Ca and Cb. By making these flow resistances approximately equal, this adjustment can be omitted. This effect can be obtained in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 of the embodiments described below in Table 1. These embodiments correspond to the examples marked "E" in the "Other" column shown in Table 1.

[0133] Furthermore, while the relationship between the flow resistance Rin of the common supply channel CF1 and the flow resistance Rout of the common discharge channel CF2 is not particularly limited, it is preferable that the flow resistance Rin of the common supply channel CF1 is larger than the flow resistance Rout of the common discharge channel CF2. For example, when a filter 25, which increases flow resistance, is provided in the common supply channel CF1 to capture foreign objects heading towards the nozzle N, as described above, the flow resistance Rin of the common supply channel CF1 is easily increased. On the other hand, since the common discharge channel CF2 is located downstream of the nozzle N, the effect of providing the filter 25 in the common discharge channel CF2 is lower than that in the common supply channel CF1, and it is less cost-effective to not provide the filter 25. In this case, the presence or absence of a filter results in a larger flow resistance Rin compared to the flow resistance Rout. This effect can be obtained in Examples 1, 2, 3, 5, 7, 8, 9, 10, and 11 of the embodiments described in Table 1 below. These embodiments correspond to the examples marked with "F" in the "Other" column of Table 1.

[0134] Furthermore, the flow resistance RBP of the bypass channels BP1 and BP2 varies depending on the type of ink used. Although it is not particularly limited as long as the relationship between the combined flow resistance Rs, flow resistance Rin, and flow resistance Rout as described above is met, it is preferable, for example, that the flow resistance RBP is 2.23 × 10 when the ink viscosity is 6.00 [m·Pa / s]. 10 [N·s / m 5 The above and 6.69×10 10 [N·s / m 5 The following applies. When the flow channel resistance RBP is within such a range, bypass flow channels BP1 and BP2 suitable for using ordinary inks can be obtained.

[0135] Furthermore, the combined flow resistance Rs of the bypass channels BP1, BP2, and multiple individual channels P varies depending on the type of ink used. While it is not particularly limited as long as the relationship between the combined flow resistance Rs, flow resistance Rin, and flow resistance Rout as described above is met, it is preferable, for example, that the combined flow resistance Rs is 1.67 × 10⁻⁶ when the ink viscosity is 6.00 [m·Pa / s]. 10 [N·s / m 5 Above and 5.02×10 10 [N·s / m 5The following applies. When the synthetic flow channel resistance Rs is within such a range, it is possible to obtain bypass channels BP1, BP2, and individual channels P suitable for using ordinary inks.

[0136] Furthermore, the flow resistance Rin of the common supply channel CF1 varies depending on the type of ink used. While it is not particularly limited as long as the combined flow resistance Rs, flow resistance Rin, and flow resistance Rout as described above are satisfied, it is preferable, for example, that the flow resistance Rin is 9.76 × 10⁻⁶ when the ink viscosity is 6.00 [m·Pa / s]. 9 [N·s / m 5 The above and 2.93×10 10 [N·s / m 5 The following applies. When the flow channel resistance Rin is within such a range, a common supply flow channel CF1 suitable for using ordinary inks can be obtained.

[0137] Furthermore, the flow resistance Rout of the shared discharge channel CF2 varies depending on the type of ink used. While it is not particularly limited as long as the combined flow resistance Rs, flow resistance Rin, and flow resistance Rout as described above are satisfied, it is preferable, for example, that the flow resistance Rout is 1.39 × 10⁻⁶ when the ink viscosity is 6.00 [m·Pa / s]. 9 [N·s / m 5 The above and 4.18×10 9 [N·s / m 5 The following applies. When the flow channel resistance Rout is within such a range, a common discharge flow channel CF2 suitable for the use of common inks can be obtained.

[0138] As described above, the bypass channel BP1 has a first portion BP1a, a second portion BP1b, and a third portion BP1c. The first portion BP1a extends along either the Z1 or Z2 direction (an example of a "first direction") and connects to the common supply channel CF1. The second portion BP1b extends along either the Z1 or Z2 direction and connects to the common discharge channel CF2. The third portion BP1c extends along a plane parallel to both the X1 or X2 direction (an example of a "second direction") and the Y1 or Y2 direction (an example of a "third direction"), and connects to both the first portion BP1a and the second portion BP1b. Here, the "first direction" is the direction in which ink is ejected from the nozzle N. The "second direction" is a direction orthogonal to the "first direction." The "third direction" is a direction orthogonal to both the "first direction" and the "second direction."

[0139] In such a bypass channel BP1, since the first part BP1a and the second part BP1b each have buckled or bent portions between them and the third part BP1c, it has the advantage of easily increasing the flow channel resistance. Furthermore, at least a portion of the bypass channels BP1 and BP2 can be mounted on the support 13, which is a component different from the head body 14. Additionally, as described above, the bypass channel BP2 has a first part BP2a, a second part BP2b, and a third part BP2c. Since it is constructed in the same manner as the bypass channel BP1, it achieves the same effect as the bypass channel BP1.

[0140] Here, as mentioned earlier, the third part BP1c appears U-shaped when viewed in the Z1 or Z2 direction. This shape of the third part BP1c has the advantage of easily increasing flow channel resistance.

[0141] Furthermore, preferably, the flow resistance of each of the first portion BP1a and the second portion BP1b is greater than the flow resistance of the third portion BP1c. Since the first portion BP1a and the second portion BP1b extend along the Z1 or Z2 direction, which serves as the thickness direction of the support 13, respectively, it is easier to reduce the cross-sectional area with good precision. Therefore, by making the flow resistance of each of the first portion BP1a and the second portion BP1b greater than the flow resistance of the third portion BP1c, it is possible to easily manufacture a bypass flow channel BP1 with the required flow resistance.

[0142] As described above, the liquid ejection device 100 has a liquid ejection head 10 and a control unit 120, which controls the ejection of ink performed by the liquid ejection head 10, as an example of a "control unit".

[0143] In this embodiment, the control unit 120 controls not only the ejection action that causes ink to be ejected from the liquid ejector head 10, but also the recovery action that restores the state of the liquid ejector head 10 and the filling action that fills the liquid ejector head 10 with ink. Here, the ejection action is, for example, the action of operating the liquid ejector head 10 based on image information to print an image based on that image information on the medium M. The recovery action is, for example, the action of eliminating ink thickening or other defects within the liquid ejector head 10 by operating the circulation mechanism 150, thereby making the ink ejection characteristics achieved by the liquid ejector head 10 approach the target characteristics. The filling action is, for example, the action of filling the liquid ejector head 10 with ink by operating the circulation mechanism 150 during the initial use of the liquid ejector head 10.

[0144] As described above, the liquid ejection device 100 includes a circulation mechanism 150, and the control unit 120 controls the operation of the circulation mechanism 150. Specifically, the control unit 120 controls the operation of the circulation mechanism 150 in such a way that the flow rate of ink per unit time achieved by the circulation mechanism 150 during the recovery or filling operation is greater than the flow rate of ink per unit time achieved by the circulation mechanism 150 during the ejection operation. The operation of the liquid ejection device 100 will be described below.

[0145] Figure 12 This is a flowchart illustrating an example of the operation of the liquid ejection device 100 according to an embodiment. Figure 12 As shown, firstly, the control unit 120 determines whether there is an indication of an ejection action in step S1. This indication is implemented, for example, through the user's operation of an input device such as an operation panel (not shown).

[0146] When there is an indication of an ejection action, the control unit 120 sets the flow rate of ink per unit time implemented by the circulation mechanism 150 to a first flow rate in step S2.

[0147] Subsequently, the control unit 120 performs the ejection operation in step S3. During this ejection operation, the control unit 120 controls the operation of the circulation mechanism 150 to achieve the first flow rate set in step S2 described above. From the viewpoint of achieving stable ejection characteristics, it is preferable that the first flow rate is fixed throughout the execution period of the ejection operation.

[0148] On the other hand, in the absence of an indication for a spraying action, or after the spraying action has ended, the control unit 120 determines in step S4 whether an indication for a recovery action exists. This indication may be implemented, for example, through user operation of an input device such as an operation panel (not shown).

[0149] When an indication of a recovery action is received, the control unit 120 sets the flow rate of ink per unit time, implemented by the circulation mechanism 150, to a second flow rate in step S5. This second flow rate is a larger amount compared to the first flow rate described above.

[0150] Subsequently, the control unit 120 performs a recovery operation in step S6. During this recovery operation, the control unit 120 controls the operation of the circulation mechanism 150 to achieve the second flow rate set in step S5 described above. Furthermore, this recovery operation is performed for a predetermined period until the ink ejection characteristics achieved by the liquid ejection head 10 reach the desired characteristics. Here, although the second flow rate only needs to be larger than the first flow rate, it is preferable to achieve a level where ink is not ejected from the nozzle N. Moreover, from the viewpoint of preventing ink from being ejected from the nozzle N, it is preferable that the second flow rate remains fixed throughout the execution period of the recovery operation.

[0151] On the other hand, in the absence of an indication for a recovery action, or after the recovery action has ended, the control unit 120 determines in step S7 whether an indication for a filling action exists. This indication may be implemented, for example, through user operation of an input device such as an operation panel (not shown).

[0152] When a filling action is indicated, the control unit 120 sets the ink flow rate per unit time implemented by the circulation mechanism 150 to a third flow rate in step S8. This third flow rate is a larger amount than the first flow rate described above. Here, although the third flow rate may be the same as or different from the second flow rate, it is preferably higher than the second flow rate. In this case, the period required for the filling action can be shortened, or leakage of ink from the nozzle N can be prevented during the recovery action.

[0153] Subsequently, the control unit 120 performs a filling operation in step S9. During this filling operation, the control unit 120 controls the operation of the circulation mechanism 150 to achieve the third flow rate set in step S8 described above. Furthermore, this filling operation is performed over a predetermined period until a predetermined amount of ink is filled into the liquid nozzle 10. Here, the third flow rate only needs to be greater than the first flow rate; it can be fixed throughout the execution period of the filling operation or it can vary.

[0154] On the other hand, in the absence of an indication of a filling action, or after the filling action has ended, the control unit 120 determines whether an end indication exists in step S10. This end indication may be implemented, for example, through user operation of an input device such as an operation panel (not shown).

[0155] If there is no end indication, the control unit 120 returns to step S1 as described above; on the other hand, if there is an end indication, it terminates the process.

[0156] As described above, the liquid ejection device 100 includes a liquid ejection head 10, a circulation mechanism 150, and a control unit 120, which is an example of a "control unit". The liquid ejection head 10 has multiple individual flow channels P, a common supply flow channel CF1, a common discharge flow channel CF2, and bypass flow channels BP1 and BP2. Nozzles N are respectively provided in the multiple individual flow channels P. The common supply flow channel CF1 supplies ink, which is an example of a "liquid", to the multiple individual flow channels P. The common discharge flow channel CF2 discharges the ink from the multiple individual flow channels P. The bypass flow channels BP1 and BP2 bypass the individual flow channels P and connect the common supply flow channel CF1 and the common discharge flow channel CF2. The circulation mechanism 150 circulates the ink supplied from the common supply flow channel CF1 by passing through the multiple individual flow channels P or the bypass flow channels BP1 and BP2 and discharging it from the common discharge flow channel CF2. The control unit 120 controls the operation of the circulation mechanism 150.

[0157] Here, the control unit 120 performs the following processing: when performing the ejection action that causes ink to be ejected from the liquid ejector head 10, the flow rate of the ink circulated by the circulation mechanism 150 per unit time is set to a first flow rate; and when performing the recovery action that restores the state of the liquid ejector head 10, the flow rate of the ink circulated by the circulation mechanism 150 per unit time is set to a second flow rate that is greater than the first flow rate. Furthermore, as described above, this ejection action is the action of ejecting ink from the liquid ejector head 10. The recovery action is the action of restoring the state of the liquid ejector head 10.

[0158] In the above-described liquid ejection device, the flow rate of ink circulated by the circulation mechanism 150 during the recovery operation is higher than that during the ejection operation. Therefore, during the ejection operation, the circulation mechanism 150 can be operated appropriately to the extent required for ink to be ejected from the liquid ejection head 10 by eliminating ink thickening, which significantly affects ejection characteristics. On the other hand, during the recovery operation, the circulation mechanism 150 can be operated to the extent required for restoring the state of the liquid ejection head 10 by removing air bubbles. Thus, since the ink flow rate only needs to be increased when necessary, there is no need to increase the number of pumps used in the circulation mechanism 150 or improve pump capacity. As a result, it is possible to reduce the cost of the liquid ejection device while reducing ink thickening or removing air bubbles.

[0159] Furthermore, during the filling operation, the control unit 120 sets the flow rate of ink supplied to the liquid nozzle 10 per unit period to a third flow rate that is greater than the first flow rate. Therefore, during the filling operation, the circulation mechanism 150 can operate to the extent required to fill the liquid nozzle 10 with ink. Additionally, as mentioned above, this filling operation is the operation of filling the liquid nozzle 10 with ink.

[0160] Here, when the third flow rate is higher than the second flow rate, the time required for the filling action can be shortened, or ink leakage from nozzle N can be prevented during the recovery action.

[0161] 2. Variations

[0162] The methods illustrated above can be modified in a variety of ways. The following sections illustrate specific modifications that can be applied to the methods described above. Any two or more methods selected from the following examples can be appropriately combined within the bounds of mutual non-contradiction.

[0163] 2-1. Variation Example 1

[0164] In the manner described above, a structure in which the flow rate of ink per unit time achieved by the circulation mechanism 150 during the recovery or filling operation is greater than that during the ejection operation has been exemplified. However, this structure is not limited to this one, and it is also possible to make the flow rate of ink per unit time achieved by the circulation mechanism 150 during the recovery or filling operation less than that during the ejection operation.

[0165] 2-2. Variation Example 2

[0166] In the manner described above, a structure in which the liquid ejection device 100 performs a recovery action and a filling action in addition to the ejection action has been illustrated, but it is not limited to this structure, and one or both of the recovery action and the filling action may be omitted.

[0167] 2-3. Variation Example 3

[0168] In the manner described above, a structure in which the liquid ejector head 10 has six head bodies 14 has been illustrated, but it is not limited to this structure. The number of head bodies 14 in the liquid ejector head 10 may be one or more and five or less, or even seven or more.

[0169] 2-4. Variation Example 4

[0170] In the manner described above, an example of using a first ink and a second ink of different types was given, but the method is not limited to this structure. The number of types of ink used in the liquid ejector head 10 may be one or more.

[0171] 2-5. Variation Example 5

[0172] The shape and other configuration of the ink flow channels within the liquid ejector head 10 are not limited to those described above, and can be appropriately modified depending on the configuration of the head body 14. Furthermore, the support 13 and the flow channel structure 11 constituting each part of the flow channel can be integrally formed.

[0173] 2-6. Variation Example 6

[0174] The liquid ejection apparatus 100 illustrated in the foregoing embodiments can be used not only in printing equipment but also in various other devices such as fax machines or copiers. Of course, the application of the liquid ejection apparatus of the present invention is not limited to printing. For example, the liquid ejection apparatus for ejecting a solution of color material is used as a manufacturing apparatus for forming a color filter in a liquid crystal display device. Furthermore, the liquid ejection apparatus for ejecting a solution of conductive material is used as a manufacturing apparatus for forming wiring and electrodes on a wiring board.

[0175] Example

[0176] The following describes specific embodiments of the present invention. However, the present invention is not limited to these embodiments.

[0177] A. Manufacturing of liquid nozzles

[0178] A-1. Example 1

[0179] Manufactured as described above Figures 3 to 10 The liquid ejector head shown has the following structure. Here, the combined flow resistance RCa of the individual supply channels included in the multiple individual flow channels is 6.39 × 10⁻⁶. 10 [N·s / m 5 The combined flow resistance RCb of the individual discharge channels contained within multiple individual flow channels is 6.39 × 10⁻⁶. 10 [N·s / m 5 The flow resistance RBP of the bypass channel is 3.12 × 10⁻⁶. 10 [N·s / m 5 The combined flow resistance Rs of the bypass channel and multiple individual channels is 2.51 × 10⁻⁶. 10 [N·s / m 5 The flow resistance Rin of the shared supply channel is 1.95 × 10⁻⁶. 10 [N·s / m 5 The flow resistance Rout of the shared discharge channel is 1.12 × 10⁻⁶. 10 [N·s / m 5 ].

[0180] Regarding these flow channel resistances, the values ​​are recorded after rounding to the first decimal place, assuming the total value of the combined flow channel resistance Rs, flow channel resistance Rin, and the flow channel resistance Rout of the shared discharge flow channel is set to 100. The combined flow channel resistance RCa of a separate supply flow channel is 115. The combined flow channel resistance RCb of a separate discharge flow channel is 115. The flow channel resistance RBP of a bypass flow channel is 56. The combined flow channel resistance Rs of the bypass flow channel and multiple separate flow channels is 45. The flow channel resistance Rin of the shared supply flow channel is 35. The flow channel resistance Rout of the shared discharge flow channel is 20.

[0181] Here, the combined flow resistance RCa+RCb of the combined flow resistance of multiple individual supply channels and the combined flow resistance RCb of multiple individual discharge channels is 229. Furthermore, since each individual channel P consists of an individual supply channel and an individual discharge channel, its combined flow resistance RCa+RCb is equal to the combined flow resistance RP of the multiple individual channels P. Therefore, the flow resistance RBP = 56 of the bypass channels BP1 and BP2 is smaller compared to the combined flow resistance RP = 229 of the individual channel P.

[0182] Furthermore, the ratio of the flow resistance RBP of bypass channels BP1 and BP2 to the combined flow resistance RP of multiple individual channels P, RBP / (RCa+RCb), is 0.24. Therefore, the flow resistance RBP of bypass channels BP1 and BP2 is 25% smaller than the combined flow resistance RP of the individual channels P.

[0183] A-2. Examples 2-15 and Reference Examples 1-12

[0184] Except that the synthetic flow channel resistance RCa, synthetic flow channel resistance RCb, flow channel resistance RBP, synthetic flow channel resistance Rs, flow channel resistance Rin and flow channel resistance Rout were set as shown in Table 1, the liquid nozzles of Examples 2 to 15 and Reference Examples 1 to 12 were manufactured in the same manner as in Example 1 described above.

[0185] Table 1

[0186]

[0187] B. Evaluation

[0188] B-1. Evaluation of Traffic Flow

[0189] The overall ink flow rate of the liquid ejector head was evaluated according to the following criteria.

[0190] A: The ink flow rate is appropriate.

[0191] B: The ink flow rate is slightly too high.

[0192] C: Excessive ink flow.

[0193] The evaluation results are as shown in the “Overall Flow” column of Table 1.

[0194] B-2. Evaluation of viscosity enhancement

[0195] The viscosity increase of ink near the nozzle of the liquid ejector head was evaluated according to the following criteria.

[0196] A: No thickening occurred.

[0197] B: Although there are no problems in actual use, there is a tendency for it to become stickier.

[0198] C: Thickening caused by problems in actual use.

[0199] The evaluation results are as shown in the “Tackification” column of Table 1.

[0200] B-3. ​​Overall Evaluation

[0201] The comprehensive evaluation of the flow rate and viscosity enhancement described above was conducted based on the following criteria.

[0202] A: There are no issues with the evaluations of traffic and user engagement from both sides.

[0203] B: There are problems with the evaluation of at least one of traffic and stickiness.

[0204] The evaluation results are as shown in the "Comprehensive" column of Table 1.

[0205] B-4. Other evaluations

[0206] Further evaluations of the various embodiments were conducted based on the following criteria.

[0207] A: The balance between the ink's viscosity and flow rate is exceptionally good.

[0208] B: A proper balance between nozzle density and overall ink flow rate.

[0209] C: A better balance between nozzle density and overall ink flow rate is more appropriate.

[0210] D: The overall ink flow rate is extremely low.

[0211] E: Reduce the deviation between the two pressure chambers.

[0212] F: Balancing foreign object capture and cost reduction.

[0213] The evaluation results are as shown in the "Other" column of Table 1. Furthermore, this evaluation may have met multiple criteria; the more criteria met, the better the evaluation.

[0214] As shown in Table 1, the embodiments achieved superior results compared to the reference examples. Furthermore, the same results were obtained for the ejection, recovery, and filling actions. Specifically, for the recovery and filling actions, it was confirmed that when the ink flow rate per unit time is greater than that of the ejection action, air bubbles in the flow channel can be appropriately removed.

[0215] Symbol Explanation

[0216] 10…Liquid ejector head; 11…Flow channel structure; 11a…Connecting pipe; 11b…Connecting pipe; 11c…Connecting pipe; 11d…Connecting pipe; 11e…Hole; 12…Wiring board; 12a…Hole; 12b…Opening; 12c…Connector; 13…Bracket; 13a…Connecting pipe; 13b…Connecting pipe; 13c…Connecting pipe; 13d…Connecting pipe; 13e…Wiring hole; 13f…Recess; 14…Head body; 14_1…Head body; 14_2…Head body; 14_3…Head body; 14_4…Head body; 14_5…Head body; 14_6…Head body; 14a…Nozzle board; 14b…Flow channel board; 14c…Pressure chamber board; 14d…Vibrating plate; 14e…Piezoelectric element; 14f… Housing; 14g…protective plate; 14h…wiring board; 14i…drive circuit; 14j…vibration absorber; 15…fixed plate; 15a…opening; 16…base; 16a…main body; 16b…assembly board; 16c…cover; 16d…hole; 16e…flange; 21…layer; 21a…concave surface; 21b…inlet; 21c…groove; 22…layer; 22a…recess; 22b…groove; 22c…hole; 22d…hole; 23…layer; 23a…groove; 24…fixing component; 24a…bottom wall; 24b…frame; 24c…first outlet; 24d…second outlet; 24i…side wall; 25…filter; 31…layer; 32…layer; 41…support; 41a…mounting hole; 100…liquid 110…Liquid container; 120…Control unit (control section); 130…Conveying mechanism; 140…Liquid ejection module; 150…Circulation mechanism; BP1…Bypass channel; BP1a…First section; BP1b…Second section; BP1c…Third section; BP2…Bypass channel; BP2a…First section; BP2b…Second section; BP2c…Third section; C…Pressure chamber; C1…First channel; C2…Second channel; CC…Supply channel; CC1…First supply channel; CC2…Second supply channel; CE1…Outlet; CE2…Outlet; CF1…Common supply channel; CF2…Common discharge channel; CI1…Inlet; CI2…Inlet; CM…Discharge channel CM1…First discharge channel; CM2…Second discharge channel; Ca…Pressure chamber; Cb…Pressure chamber; Com…Drive signal; DM…Direction; DN…Arrangement direction; DS…Individual discharge channel; DS1…First individual discharge channel; DS2…Second individual discharge channel; FN…Nozzle face; IO1…Inlet; IO2…Outlet; IO3a…Outlet; IO3b…Outlet; IO4a…Inlet; IO4b…Inlet; Ln…Nozzle array; M…Medium; N…Nozzle; Na1…First connecting channel; Na2…Second connecting channel; Nf…Nozzle channel; P…Individual channel; R1…First common liquid chamber; R2…Second common liquid chamber; RBP…Channel resistance; RCa…Combined channel resistance;RCb…Synthetic flow channel resistance; RF1…First filter chamber; RF2…Second filter chamber; RFa…Upstream chamber; RFb…Downstream chamber; RP…Synthetic flow channel resistance; Ra1…Individual supply channel; Ra2…Individual discharge channel; Rin…Flow channel resistance; Rout…Flow channel resistance; Rs…Synthetic flow channel resistance; S1…Step; S10…Step; S2…Step; S3…Step; S4…Step; S5…Step; S6…Step; S7…Step; S8…Step; S9…Step; SP…Distribution supply channel; SP1…First distribution supply channel; SP2…Second distribution supply channel; SPa…Longitudinal channel; SPb…Cross channel.

Claims

1. A liquid ejector head, characterized in that, have: Multiple individual flow channels, each equipped with a nozzle; A common supply channel supplies liquid to the plurality of individual channels; A common discharge channel is provided, which allows liquid to be discharged from the plurality of individual channels; A bypass channel that detours through the plurality of individual channels and connects the common supply channel with the common discharge channel; The combined flow resistance of the bypass channel and the plurality of individual channels is greater than the flow resistance of the common supply channel and also greater than the flow resistance of the common discharge channel. The flow resistance of the bypass channel is smaller compared to the combined flow resistance of the plurality of individual channels. The flow resistance of the bypass channel is more than 25% relative to the combined flow resistance of the plurality of individual channels.

2. The liquid ejector head as described in claim 1, characterized in that, The flow resistance of the bypass channel is less than 55% relative to the combined flow resistance of the plurality of individual channels.

3. A liquid ejector head, characterized in that, have: Multiple individual flow channels, each equipped with a nozzle; A common supply channel supplies liquid to the plurality of individual channels; A common discharge channel is provided, which allows liquid to be discharged from the plurality of individual channels; A bypass channel that detours through the plurality of individual channels and connects the common supply channel with the common discharge channel; The combined flow resistance of the bypass channel and the plurality of individual channels is greater than the flow resistance of the common supply channel and also greater than the flow resistance of the common discharge channel. When the direction in which liquid is ejected from the nozzle is defined as the first direction, the direction orthogonal to the first direction is defined as the second direction, and the direction orthogonal to both the first and second directions is defined as the third direction, the bypass channel has the following first, second, and third portions: the first portion extends along the first direction and is connected to the common supply channel; the second portion extends along the first direction and is connected to the common discharge channel; and the third portion extends along a plane parallel to both the second and third directions and is connected to the first and second portions respectively. The flow resistance of the first and second parts is greater than that of the third part.

4. The liquid ejector head as described in claim 3, characterized in that, The third part appears U-shaped when viewed along the first direction.

5. The liquid ejector head as described in claim 1, characterized in that, The combined flow resistance of the bypass channel and the plurality of individual channels is 50% or more and 70% or less relative to the combined flow resistance of the bypass channel, the plurality of individual channels, the common supply channel, and the common discharge channel.

6. The liquid ejector head as described in claim 3, characterized in that, The flow resistance of the bypass channel is smaller compared to the combined flow resistance of the plurality of individual channels.

7. The liquid ejector head as described in any one of claims 1 to 4, characterized in that, Each of the plurality of individual flow channels includes a pressure chamber for applying pressure to eject liquid from the plurality of nozzles, a separate supply flow channel for supplying liquid to the pressure chamber, and a separate discharge flow channel for discharging liquid from the pressure chamber.

8. The liquid ejector head as described in claim 7, characterized in that, The flow resistance of the bypass channel is smaller than the combined flow resistance of the individual supply channels included in the plurality of individual channels.

9. The liquid ejector head as described in claim 7, characterized in that, The flow resistance of the bypass channel is smaller compared to the combined flow resistance of the individual discharge channels included in the plurality of individual channels.

10. The liquid ejector head as described in claim 7, characterized in that, The flow resistance of each individual supply channel included in the plurality of individual flow channels is approximately equal to the flow resistance of each individual discharge channel included in the plurality of individual flow channels.

11. The liquid ejector head as described in claim 1 or 3, characterized in that, The flow resistance of the shared supply channel is greater than that of the shared discharge channel.

12. The liquid ejector head as described in claim 1 or 3, characterized in that, With a liquid viscosity of 6.00 mPa / s, the flow resistance of the bypass channel is 2.23 × 10⁻⁶. 10 N·s / m 5 The above and 6.69×10 10 N·s / m 5 the following.

13. The liquid ejector head as described in claim 1 or 3, characterized in that, With a liquid viscosity of 6.00 mPa / s, the combined flow resistance of the bypass channel and the plurality of individual channels is 1.67 × 10⁻⁶. 10 N·s / m 5 Above and 5.02×10 10 N·s / m 5 the following.

14. The liquid ejector head as described in claim 1 or 3, characterized in that, With a liquid viscosity of 6.00 mPa / s, the flow resistance of the common supply channel is 9.76 × 10⁻⁶. 9 N·s / m 5 Above and 2.93×10 10 N·s / m 5 the following.

15. The liquid ejector head as described in claim 1 or 3, characterized in that, With a liquid viscosity of 6.00 mPa / s, the flow resistance of the common discharge channel is 1.39 × 10⁻⁶. 9 N·s / m 5 The above and 4.18×10 9 N·s / m 5 the following.

16. A liquid ejection device, characterized in that, have: The liquid ejector head as described in any one of claims 1 to 15; The control unit controls the liquid ejection action performed by the liquid ejection head.

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