Liquid ejection device

Abstract

A liquid ejecting apparatus is provided. The liquid ejecting apparatus has a liquid ejecting head having a plurality of individual flow paths provided with nozzles, a common supply flow path that supplies liquid to the plurality of individual flow paths, a common discharge flow path that discharges liquid from the plurality of individual flow paths, and a bypass flow path that bypasses the plurality of individual flow paths and communicates the common supply flow path with the common discharge flow path; a circulation mechanism that circulates liquid supplied from the common supply flow path in a manner that the liquid passes through the plurality of individual flow paths or the bypass flow path and is discharged from the common discharge flow path; and a control section that controls operation of the circulation mechanism, the control section setting a flow rate per unit time of liquid circulated by the circulation mechanism to a first flow rate when performing an ejection operation in which liquid is ejected from the liquid ejecting head, and setting the flow rate per unit time of liquid circulated by the circulation mechanism to a second flow rate that is greater than the first flow rate when performing a recovery operation in which a state of the liquid ejecting head is recovered.

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid ejection apparatus. BACKGROUND

[0002] In a liquid ejection apparatus typified by an inkjet printer, there are cases where a structure is provided to circulate a liquid in a liquid ejection head that ejects a liquid such as ink, as disclosed in Patent Literature 1 and Patent Literature 2, for example.

[0003] The head described in Patent Literature 1 has a plurality of pressure generating chambers that communicate with nozzle openings, a first manifold and a second manifold that communicate with the plurality of pressure generating chambers, and a bypass flow passage that connects these manifolds by a system other than the pressure generating chambers. In this case, in the first manifold, ink is supplied from an ink tank by a driving force of a pump. The ink circulates in a path that returns to the ink tank after flowing into the second manifold from the first manifold via the pressure generating chambers or the bypass flow passage. In Patent Literature 1, when the flow passage resistance of the bypass flow passage is set to R, the flow passage resistance of a flow passage that connects 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] The head described in Patent Literature 2 has a plurality of pressure chambers that communicate with nozzles, a supply-side common flow passage that stores a liquid supplied to the pressure chambers through a liquid supply passage, a circulation-side common flow passage that stores a liquid recovered from the pressure chambers through a liquid circulation passage, and a bypass flow passage that causes the liquid to flow from the supply-side common flow passage to the circulation-side common flow passage. In this case, when the flow passage resistance of the bypass flow passage is set to R, the number of pressure chambers is set to N, and the flow passage resistance from the liquid supply passage to the liquid circulation passage via the pressure chambers is set to r, the relationship of r / N < R < r is satisfied.

[0005] In the above-described structure that circulates a liquid, even if the liquid is circulated at a small flow rate, it is possible to suppress an increase in viscosity of the liquid. However, in order to remove bubbles in the flow passage, it is necessary to increase the flow rate of the circulated liquid compared to the above case. In the related art, since the flow rate of the circulated liquid is fixed, if bubbles in the flow passage are to be removed, a large capacity of the pump is incurred. Therefore, in the related art, there is a problem that it is not possible to reduce thickening of ink or removal of bubbles while achieving cost reduction.

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

[0007] Patent Literature 2: Japanese Patent Application Publication No. 2010-214847 SUMMARY

[0008] To solve the above problems, a liquid ejecting apparatus according to a preferred embodiment of the present application includes: a liquid ejecting head having a plurality of individual flow paths provided with nozzles, a common supply flow path that supplies liquid to the plurality of individual flow paths, a common discharge flow path that discharges liquid from the plurality of individual flow paths, and a bypass flow path that bypasses the plurality of individual flow paths and connects the common supply flow path and the common discharge flow path; a circulation mechanism that circulates liquid supplied from the common supply flow path through the plurality of individual flow paths or the bypass flow path to be discharged from the common discharge flow path; and a control section that controls operation of the circulation mechanism, the control section setting a flow rate per unit time of liquid circulated by the circulation mechanism to a first flow rate when performing an ejection operation of ejecting liquid from the liquid ejecting head, and setting the flow rate per unit time of liquid circulated by the circulation mechanism to a second flow rate that is larger than the first flow rate when performing a recovery operation of recovering a state of the liquid ejecting head.

[0009] A liquid ejecting apparatus according to another preferred embodiment of the present application includes: a liquid ejecting head having a plurality of individual flow paths provided with nozzles, a common supply flow path that supplies liquid to the plurality of individual flow paths, a common discharge flow path that discharges liquid from the plurality of individual flow paths, and a bypass flow path that bypasses the plurality of individual flow paths and connects the common supply flow path and the common discharge flow path; a circulation mechanism that circulates liquid supplied from the common supply flow path through the plurality of individual flow paths or the bypass flow path to be discharged from the common discharge flow path; and a control section that controls operation of the circulation mechanism, the control section setting a flow rate per unit time of liquid circulated by the circulation mechanism to a first flow rate when performing an ejection operation of ejecting liquid from the liquid ejecting head, and setting a flow rate per unit time of liquid supplied to the liquid ejecting head to a third flow rate that is larger than the first flow rate when performing a filling operation of filling the liquid ejecting head with liquid. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 A schematic diagram showing a structure example of a liquid ejecting apparatus according to an embodiment.

[0011] Figure 2 A perspective view of a liquid ejecting module having a liquid ejecting head according to an embodiment.

[0012] Figure 3 A perspective view of a liquid ejecting head according to an embodiment. Figure 2 An exploded perspective view of a liquid ejecting head according to an embodiment.

[0013] Figure 4A plan view of a flow path of a head main body possessed by the liquid ejection head.

[0014] Figure 5 A sectional view of a head main body possessed by the liquid ejection head.

[0015] Figure 6 A plan view of a support.

[0016] Figure 7 A perspective view of a flow path and a head main body provided on the support.

[0017] Figure 8 A sectional view of A-A line in Figure 6

[0018] Figure 9 A plan view of a flow path structure.

[0019] Figure 10 A sectional view of B-B line in Figure 9

[0020] Figure 11 An equivalent circuit diagram of a flow path provided on the liquid ejection head.

[0021] Figure 12 A flowchart showing one example of an operation of the liquid ejection apparatus according to the embodiment. DETAILED DESCRIPTION

[0022] Hereinafter, preferred embodiments according to the present application will be described with reference to the accompanying drawings. In each drawing, the size and the scale of each portion and the scale of proportionality are appropriately different from the actual situation, and some portions are schematically shown for easy understanding. Further, in the following description, the scope of the present application is not limited to these modes as long as there is no description that particularly limits the present application.

[0023] For the convenience of explanation, the following description is made using X axis, Y axis, and Z axis that cross each other. Further, one direction along the X axis is XI direction, and the direction opposite to the XI direction is X2 direction. The XI direction or the X2 direction is one example of a "second direction". Similarly, the directions opposite to each other along the Y axis are Yl direction and Y2 direction. The Yl direction or the Y2 direction is one example of a "third direction". Further, the directions opposite to each other along the Z axis are Zl direction and Z2 direction. The Zl direction or the Z2 direction is one 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 each element of the liquid discharge apparatus 100. The control unit 120 includes, for example, one or a plurality of processing circuits such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array), and one or a plurality of storage circuits such as a semiconductor memory. Various programs and various data are stored in the storage circuit. The processing circuit realizes various controls by executing the programs and appropriately using the data.

[0032] The transport mechanism 130 transports the medium M in the direction DM based on the control performed by the control unit 120. The direction DM of the present embodiment is the Y2 direction. The transport mechanism 130 transports the medium M in the Y2 direction in accordance with the control performed by the control unit 120. Figure 1 In the example illustrated, the transport mechanism 130 includes a transport roller elongated along the X axis, and a motor that rotates the transport roller. In addition, the transport mechanism 130 is not limited to a structure using a transport roller, and can be, for example, a structure using a drum or a endless belt that transports the medium M in a state in which the medium M is adsorbed to the outer peripheral surface by electrostatic force or the like.

[0033] The liquid discharge module 140 discharges the ink supplied from the liquid container 110 via the circulation mechanism 150 from each of the plurality of nozzles in the Z2 direction based on the control performed by the control unit 120. The liquid discharge module 140 is a line head having a plurality of liquid discharge heads 10 that are arranged in a manner such that the plurality of nozzles are distributed across the entire range of the medium M in the direction along the X axis. That is, the collection of the plurality of liquid discharge heads 10 constitutes a line head elongated in the direction along the X axis. By performing the discharge of the ink from the plurality of liquid discharge heads 10 in parallel with the transport of the medium M performed by the transport mechanism 130, an image generated by the ink is formed on the surface of the medium M. In addition, it is also possible to arrange one liquid discharge head 10 in a manner such that the plurality of nozzles possessed by the one liquid discharge head 10 are distributed across the entire range of the medium M in the direction along the X axis, in which case, for example, the liquid discharge module 140 is constituted by the one liquid discharge head 10.

[0034] On the liquid ejection module 140, the liquid container 110 is connected via a circulation mechanism 150. The circulation mechanism 150 is a mechanism that supplies ink to the liquid ejection module 140 based on control performed by the control unit 120, and performs recovery for performing resupply of ink discharged from the liquid ejection module 140 to the liquid ejection module 140. The circulation mechanism 150 has, for example, a sub-tank that stores ink, a supply flow path for supplying ink from the sub-tank to the liquid ejection module 140, a recovery flow path for recovering ink from the liquid ejection module into the sub-tank, and a pump for appropriately flowing ink. These circulation mechanisms are provided for each of the first liquid container and the second liquid container described above. By the operation of the above circulation mechanism 150, it is possible to suppress an increase in viscosity of ink, or reduce the retention of air bubbles in ink.

[0035] 1-2. Liquid ejection module 140

[0036] Figure 2 A perspective view of the liquid ejection module 140 having the liquid ejection head 10 according to the embodiment. As shown in Figure 2 , the liquid ejection module 140 has a support body 41 and a plurality of liquid ejection heads 10. The support body 41 is a member that supports the plurality of liquid ejection heads 10. In Figure 2 the example shown, the support body 41 is a plate-shaped member composed of metal or the like, and mounting holes 41a for mounting the plurality of liquid ejection heads 10 are provided therein. The plurality of liquid ejection heads 10 are inserted into the mounting holes 41a in a state of being arranged in the direction along the X axis, and each liquid ejection head 10 is fixed to the support body 41 by screw fastening or the like. In Figure 2 , two liquid ejection heads 10 are schematically illustrated. In addition, the number of liquid ejection heads 10 in the liquid ejection module 140 is an arbitrary number. Furthermore, the shape or the like of the support body 41 is not limited to the example shown in Figure 2 , but is an arbitrary shape.

[0037] 1-3. Liquid ejection head 10

[0038] Figure 3 An exploded perspective view of the liquid ejection head 10 shown in Figure 2 . As shown in Figure 3As 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 substrate 12 is a mounting member for electrically connecting the plurality of head bodies 14 and the collective substrate 16b described later. The wiring substrate 12 is, for example, a rigid wiring substrate. The wiring substrate 12 is disposed between the flow channel structure 11 and the holder 13, and a connector 12c is provided on a surface of the wiring substrate 12 that faces the flow channel structure 11. The connector 12c is a connecting member that connects with the collective substrate 16b described later. Further, a plurality of holes 12a and a plurality of opening portions 12b are provided on the wiring substrate 12. Each hole 12a is a hole for allowing connection of the flow channel structure 11 and the holder 13. Each opening portion 12b is a hole through which a wiring substrate 14h that connects the head body 14 and the wiring substrate 12 passes. The wiring substrate 14h is connected to a surface of the wiring substrate 12 that faces the Z1 direction. The wiring substrate 14h is a member that includes a wiring that is electrically connected to the piezoelectric element 14e described later, and is, for example, an FPC (Flexible Printed Circuits) or a COF (Chip On Film), or the like.

[0043] The holder 13 is a structure that houses and supports the plurality of head bodies 14. The holder 13 is, for example, composed of a resin material or a metal material, or the like. The holder 13 is in the shape of a plate that extends in a direction perpendicular to the Z axis. Further, a connection pipe 13a, a connection pipe 13b, a plurality of connection pipes 13c, a plurality of connection pipes 13d, and a plurality of wiring holes 13e are provided on the holder 13. Further, although not illustrated, a plurality of recesses that house the plurality of head bodies 14 are provided on a surface of the holder 13 that faces the Z2 direction.

[0044] In the present embodiment, six head bodies 14_1 to 14_6 are held on the holder 13. These head bodies are arranged in the X2 direction in the order of the head bodies 14_1, 14_4, 14_2, 14_5, 14_3, 14_6. Here, the head bodies 14_1 to 14_3 are disposed at positions that are offset in the Y1 direction with respect to the head bodies 14_4 to 14_6. However, the head bodies 14_1 to 14_6 have portions that overlap each other when viewed in the X1 direction or the X2 direction. Further, arrangement directions DN of the plurality of nozzles N of the head bodies 14_1 to 14_6 described later are parallel to each other. Also, the head bodies 14_1 to 14_6 are each disposed in a manner in which the arrangement direction DN is inclined with respect to a direction DM that is the transport direction of the medium M.

[0045] Here, although in the present embodiment, the head bodies 14_1 to 14_6 are arranged in the X2 direction in the order of the head bodies 14_1, 14_4, 14_2, 14_5, 14_3, 14_6, the head bodies 14_1 to 14_6 can be arranged in the X1 direction in the order of the head bodies 14_6, 14_3, 14_5, 14_2, 14_4, 14_1. Figure 3The first distribution supply flow passage is a flow passage having branches for supplying the first ink to the plurality of head bodies 14. The second distribution supply flow passage is a flow passage having branches for supplying the second ink to the plurality of head bodies 14. The first individual discharge flow passage is a flow passage provided for each head body 14 that discharges the first ink, and for introducing the first ink discharged from the head body 14 to the first discharge flow passage of the flow passage structure 11. The second individual discharge flow passage is a flow passage provided for each head body 14 that discharges the second ink, and for introducing the second ink discharged from the head body 14 to the second discharge flow passage of the flow passage structure 11. The bypass flow passage is a flow passage provided with two for each head body 14, and communicates the first common liquid chamber R1 and the second common liquid chamber R2 described later. In addition, regarding the flow passages of the bracket 13, explanation will be made based on the Figures 6 to 8

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

[0047] The connection pipes 13a, 13b, 13c, and 13d are tubular projections projecting in the Z1 direction. More specifically, the connection pipe 13a is a pipe body constituting a flow passage for supplying the first ink to the first distribution supply flow passage, and communicates with the first supply flow passage of the flow passage structure 11. Further, the connection pipe 13b is a pipe body constituting a flow passage for supplying the second ink to the second distribution supply flow passage, and communicates with the second supply flow passage of the flow passage structure 11. On the other hand, the connection pipe 13c is a pipe body constituting a flow passage for discharging the first ink from the first individual discharge flow passage, and communicates with the first discharge flow passage of the flow passage structure 11. Further, the connection pipe 13d is a pipe body constituting a flow passage for discharging the second ink from the second individual discharge flow passage, and communicates with the second discharge flow passage of the flow passage structure 11. The wiring hole 13e is a hole through which a wiring substrate 14h for connecting the head body 14 and the wiring substrate 12 passes.

[0048] Each head body 14 ejects ink. Specifically, although illustration is omitted in Figure 3 Each head body 14 has a plurality of nozzles that eject the first ink, and a plurality of nozzles that eject the second ink. These nozzles are provided on a face of each head body 14 that faces the Z2 direction, that is, a nozzle face FN. Regarding the details of the head body 14, explanation will be made based on the Figure 4

[0049] ​​The fixing plate 15 is a plate member for fixing the plurality of head bodies 14 to the bracket 13. Specifically, the fixing plate 15 is configured in a state of sandwiching the plurality of head bodies 14 between the bracket 13, and is fixed to the bracket 13 by an adhesive. The fixing plate 15 is composed of, for example, a metal material or the like. A plurality of opening portions 15a for exposing the nozzles of the plurality of head bodies 14 are provided in the fixing plate 15. In the example shown, the plurality of opening portions 15a are provided individually for each head body 14. Alternatively, the opening portions 15a can be in a form shared by two or more head bodies 14. Figure 3 In the example shown, the plurality of opening portions 15a are provided individually for each head body 14. Alternatively, the opening portions 15a can be in a form shared by two or more head bodies 14.

[0050] The base 16 is a member for fixing the flow channel structure 11, the wiring substrate 12, the bracket 13, the plurality of head bodies 14, and the fixing plate 15 to the support body 41 described above. The base 16 has a main body 16a, a collective substrate 16b, and a cover 16c.

[0051] The main body 16a is fixed to the bracket 13 by screw fastening or the like, thereby holding the flow channel structure 11 and the wiring substrate 12 disposed between the base 16 and the bracket 13. The main body 16a is composed of, for example, a resin material or the like. The main body 16a has a plate-shaped portion opposed to the plate-shaped portion of the flow channel structure 11 described above, and a plurality of holes 16d for inserting the connection pipes 11a, 11b, 11c, and 11d described above are provided in the plate-shaped portion. Further, the main body 16a has a portion extending from the plate-shaped portion in the Z2 direction, and a flange 16e for fixing to the support body 41 described above is provided at the tip end of the portion.

[0052] The collective substrate 16b is a mounting member for electrically connecting the control unit 120 and the wiring substrate 12 described above. The collective substrate 16b is, for example, a rigid wiring substrate. The cover 16c is a plate-shaped member for protecting the collective substrate 16b and fixing the collective substrate 16b to the main body 16a. The cover 16c is composed of, for example, a resin material or the like, and is fixed to the main body 16a by screw fastening or the like.

[0053] 1-4. Head body 14

[0054] Figure 4 A plan view schematically showing a flow channel of the head body 14 possessed by the liquid ejection head 10. For ease of explanation, the following explanation is made using the V axis and the W axis in addition to the X axis, the Y axis, and the Z axis. Further, one direction along the V axis is the V1 direction, and the direction opposite to the V1 direction is the V2 direction. Similarly, the directions opposite to each other 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 4 As 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, the plurality of pressure chambers Ca are arranged along the V-axis. Similarly, the plurality of pressure chambers Cb are arranged along the V-axis. In addition, in each individual flow path P, the positions of the pressure chambers Ca and the pressure chambers Cb in the direction along the V-axis are different. Figure 4 In the example shown, the pressure chambers Ca and the pressure chambers Cb are identical to each other, but can also be different from each other. In addition, hereinafter, in the case where the pressure chambers Ca and the pressure chambers Cb are not particularly distinguished from each other, each of them will be sometimes referred to as "pressure chamber C".

[0062] A nozzle flow path Nf is arranged between the pressure chamber Ca and the pressure chamber Cb of each individual flow path P. Here, the pressure chamber Ca communicates with the nozzle flow path Nf via a first communication flow path Nal extending along the Z-axis. The pressure chamber Cb communicates with the nozzle flow path Nf via a second communication flow path Na2 extending along the Z-axis.

[0063] In each individual flow path P, the nozzle flow path Nf is a space extending along the W-axis. In addition, a plurality of nozzle flow paths Nf are arranged along the V-axis at intervals from each other. A nozzle N is provided in each nozzle flow path Nf. In each nozzle flow path Nf, ink is ejected from the nozzle N by changing the pressure in the pressure chamber Ca and the pressure chamber Cb described above.

[0064] The first communication flow path Nal and the second communication flow path Na2 are each a space extending along the Z-axis. In addition, the first communication flow path Nal and the second communication flow path Na2 need only be provided as required, and can be omitted.

[0065] A first common liquid chamber Rl and a second common liquid chamber R2 communicate with a plurality of individual flow paths P. Here, the pressure chamber Ca communicates with the first common liquid chamber Rl via an individual supply flow path Ral extending along the Z-axis. The pressure chamber Cb communicates with the second common liquid chamber R2 via an individual discharge flow path Ra2 extending along the Z-axis.

[0066] The first common liquid chamber Rl and the second common liquid chamber R2 are each a space extending along the V-axis across the entire range in which the plurality of nozzles N are distributed. Here, the first common liquid chamber Rl is connected to one end in the W2 direction of each individual flow path P. In the first common liquid chamber Rl, ink for supplying to each individual flow path P is stored. On the other hand, the second common liquid chamber R2 is connected to one end in the Wl direction of each individual flow path P. In the second common liquid chamber R2, ink that is not used for ejection but is discharged from each individual flow path P is stored.

[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 pipe for introducing ink from the distribution supply flow passage SP of the holder 13 to the first common liquid chamber R1. The discharge port IO3a is a pipe for discharging ink from the first common liquid chamber R1 to the bypass flow passage BP1. The discharge port IO3b is a pipe for discharging ink from the first common liquid chamber R1 to the bypass flow passage BP2. In addition, the distribution supply flow passage SP is the first distribution supply flow passage SP1 or the second distribution supply flow passage SP2 described later.

[0068] Here, the distribution supply flow passage SP is connected to the circulation mechanism 150 via the supply flow passage CC of the flow passage structure 11. Therefore, the flow passage from the connection pipe 11a or the connection pipe 11b to the first common liquid chamber R1 is provided in common for the plurality of pressure chambers C, and constitutes a common supply flow passage CF1 that supplies ink to the plurality of individual flow passages P. In addition, the supply flow passage CC is the first supply flow passage CC1 or the second supply flow passage CC2 described later. Furthermore, although not illustrated in Figure 4 In the common supply flow passage CF1, in addition to the first common liquid chamber R1, the distribution supply flow passage SP, and the supply flow passage CC, the first filter chamber RF1 or the second filter chamber RF2 described later is included. In more detail, the common supply flow passage CF1 refers to the flow passage in the range from immediately after the portion (connection pipe 11a, connection pipe 11b) to which a hose for supplying liquid from the outside of the liquid ejecting head 10 is connected to immediately before the individual flow passage P among the components that constitute the liquid ejecting head 10. That is, the supply flow passage CF1 is the flow passage 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, a guide port IO4a, and a guide port IO4b. The discharge port IO2 is a pipe for discharging ink from the second common liquid chamber R2 to the individual discharge flow passage DS of the holder 13. The guide port IO4a is a pipe for introducing ink from the bypass flow passage BP1 to the second common liquid chamber R2. The guide port IO4b is a pipe for introducing ink from the bypass flow passage BP2 to the second common liquid chamber R2. In addition, the individual discharge flow passage DS is the first individual discharge flow passage DS1 or the second individual discharge flow passage DS2 described later.

[0070] Here, the individual discharge flow passage DS is connected to the circulation mechanism 150 via the discharge flow passage CM of the flow passage structure 11. Therefore, the flow passage from the second common liquid chamber R2 to the connection pipe 11a or the connection pipe 11b is provided in common for the plurality of pressure chambers C, and constitutes a common discharge flow passage CF2 that discharges ink from the plurality of individual flow passages P. In addition, the discharge flow passage CM is the first discharge flow passage CM1 or the second discharge flow passage CM2 described later. The common discharge flow passage CF2 refers to a path in a range from immediately after the individual flow passage P to immediately before a portion (connection pipe 11c, connection pipe 11d) to which a hose for discharging liquid to the outside of the liquid ejecting head 10 is connected, among the components that constitute the liquid ejecting head 10.

[0071] Figure 5 A cross-sectional view of the head body 14 possessed by the liquid ejecting head 10 is shown in FIG. 1. In FIG. 1, a cross section of the head body 14 cut by a plane including the W axis and the Z axis is shown. As shown in FIG. 1, the head body 14 has a nozzle substrate 14a, a flow passage substrate 14b, a pressure chamber substrate 14c, and a vibration plate 14d, a plurality of piezoelectric elements 14e, a case 14f, a protection plate 14g, and a wiring substrate 14h. Figure 5 Figure 5 As shown in FIG. 1, the head body 14 has the nozzle substrate 14a, the flow passage substrate 14b, the pressure chamber substrate 14c, and the vibration plate 14d, the plurality of piezoelectric elements 14e, the case 14f, the protection plate 14g, and the wiring substrate 14h.

[0072] The nozzle substrate 14a, the flow passage substrate 14b, the pressure chamber substrate 14c, and the vibration plate 14d are laminated in this order in the Zl direction. These components extend along the V axis, and are manufactured, for example, by processing a single-crystal substrate of silicon using a semiconductor processing technique. In addition, these components are joined to each other by an adhesive or the like. In addition, other layers or substrates such as an adhesive layer can be appropriately interposed between adjacent two of these components.

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

[0074] On the flow passage substrate 14b, a portion of each of the first common liquid chamber Rl and the second common liquid chamber R2, and a portion of each of the plurality of individual flow passages P other than the pressure chamber Ca and the pressure chamber Cb are provided. That is, on the flow passage substrate 14b, a nozzle flow passage Nf, a first communication flow passage Nal, a second communication flow passage Na2, an individual supply flow passage Ral, and an individual discharge flow passage Ra2 are provided.

[0075] The portion of each of the first common liquid chamber Rl and the second common liquid chamber R2 is a space that penetrates the flow passage substrate 14b. On a surface of the flow passage substrate 14b facing the Z2 direction, a vibration absorbing body 14j that closes an opening formed by the space is provided.

[0076] ​The damper 14j is a layered member made of an elastic material. The damper 14j constitutes a part of the wall surface of each 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 flow channel Nf is a space provided in a groove on the face of the flow channel substrate 14b facing the Z2 direction. Here, the nozzle substrate 14a constitutes a part of the wall surface of the nozzle flow channel Nf.

[0078] The first communication flow channel Na1 and the second communication flow channel Na2 are each a space that penetrates the flow channel substrate 14b.

[0079] The individual supply flow channel Ra1 and the individual discharge flow channel Ra2 are each a space that penetrates the flow channel substrate 14b. The individual supply flow channel Ra1 communicates the first common liquid chamber R1 with the pressure chamber Ca, and supplies ink from the first common liquid chamber R1 to the pressure chamber Ca. Here, one end of the individual supply flow channel Ra1 opens on the face of the flow channel substrate 14b facing the Z1 direction. On the other hand, the other end of the individual supply flow channel Ra1 is the end on the upstream side of the individual flow channel P, and opens on the wall surface of the first common liquid chamber R1 of the flow channel substrate 14b. In contrast, the individual discharge flow channel Ra2 communicates the second common liquid chamber R2 with the pressure chamber Cb, and discharges ink from the pressure chamber Cb to the second common liquid chamber R2. Here, one end of the individual discharge flow channel Ra2 opens on the face of the flow channel substrate 14b facing the Z1 direction. On the other hand, the other end of the individual discharge flow channel Ra2 is the end on the downstream side of the individual flow channel P, and opens on the wall surface of the second common liquid chamber R2 of the flow channel substrate 14b.

[0080] The pressure chamber Ca and the pressure chamber Cb, in which a plurality of individual flow channels P are provided, are provided on the pressure chamber substrate 14c. The pressure chamber Ca and the pressure chamber Cb each penetrate the pressure chamber substrate 14c, and are each a gap between the flow channel substrate 14b and the vibration plate 14d.

[0081] The vibration plate 14d is a plate-shaped member that can elastically vibrate. The vibration plate 14d is, for example, a laminate including a first layer made of silicon oxide (SiO2) and a second layer made of zirconium oxide (ZrO2). Here, another layer of a metal oxide or the like can be interposed between the first layer and the second layer. In addition, a part or all of the vibration plate 14d can be made of the same material as the pressure chamber substrate 14c so as to be integrated. For example, by selectively removing a part in the thickness direction of a plate-shaped member of a predetermined thickness with respect to a region corresponding to the pressure chamber C, the vibration plate 14d and the pressure chamber substrate 14c can be integrally formed. Furthermore, the vibration plate 14d can be made of a single layer of a material.

[0082] On the surface of the vibration plate 14d facing the Zl direction, a plurality of piezoelectric elements 14e corresponding to mutually different pressure chambers C are provided. Each piezoelectric element 14e is configured, for example, by lamination of a first electrode and a second electrode, 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 causing a pressure fluctuation of the ink in the pressure chamber C. The piezoelectric element 14e is caused to vibrate by being supplied with a drive signal Com, thereby causing the vibration plate 14d to vibrate in conjunction with deformation thereof. The pressure chamber C expands and contracts in conjunction with this vibration, thereby causing a pressure fluctuation of the ink in the pressure chamber C.

[0083] The housing 14f is a housing for storing ink. On the housing 14f, a space constituting the remaining portion of the first common liquid chamber Rl and the second common liquid chamber R2 other than the portion provided on the flow channel substrate 14b is provided.

[0084] The protection plate 14g is a plate-shaped member provided on the surface of the vibration plate 14d facing the Zl direction, which protects the plurality of piezoelectric elements 14e and reinforces the mechanical strength of the vibration plate 14d. Here, a space in which the plurality of piezoelectric elements 14e are accommodated is formed between the protection plate 14g and the vibration plate 14d.

[0085] The wiring substrate 14h is mounted on the surface of the vibration plate 14d facing the Zl direction, and is a mounting member for electrically connecting the control unit 120 and the head main body 14. It is preferable, for example, to use a flexible wiring substrate 14h such as an FPC (Flexible Printed Circuit) or an FFC (Flexible Flat Cable). The drive circuit 14i described above is mounted on the wiring substrate 14h.

[0086] In the head main body 14 of the above structure, the ink is circulated in the first common liquid chamber Rl, the individual supply flow channel Ral, the pressure chamber Ca, the nozzle flow channel Nf, the pressure chamber Cb, the individual discharge flow channel Ra2, and the second common liquid chamber R2 in that order by the operation of the circulation mechanism 150 described above.

[0087] Further, the piezoelectric elements 14e corresponding to both the pressure chamber Ca and the pressure chamber Cb are simultaneously driven by the drive signal Com from the drive circuit 14i, thereby causing a pressure fluctuation of the pressure chamber Ca and the pressure chamber Cb, and ejecting the ink from the nozzle N in conjunction with this pressure fluctuation. In addition, the operation of the circulation mechanism 150 will be described based on the description below. Figure 12

[0088] 1-5. Support 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 7 As 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. In Figure 8 In addition to the bracket 13, the diagram also shows the head body 14 and the fixing plate 15. Figure 8As shown, the bracket 13 is in a plate shape that expands in a direction perpendicular to the Z axis. The bracket 13 has a layer 31 and a layer 32 that are laminated in this order in the Z2 direction. The layers 31 and 32 are each composed of, for example, a resin material and are formed by injection molding. The layers 31 and 32 are joined to each other by, for example, an adhesive.

[0095] The bracket 13 has the flow passages described above provided on the laminate composed of the layers 31 and 32, and has a recess 13f that receives the head body 14 provided on a surface of the layer 32 facing the Z2 direction. In Figure 8 In the example shown, the layer 32 is thicker than the layer 31. Therefore, the thickness of the layer 32 required for formation of the recess 13f can be easily ensured.

[0096] Here, the first distribution supply flow passage SP1 has a longitudinal flow passage SPa and a lateral flow passage SPb. The longitudinal flow passage SPa extends in a direction along the Z axis and is composed of a hole that penetrates the layer 32. The lateral flow passage SPb extends in a direction orthogonal to the Z axis and is provided between the layers 31 and 32. In Figure 8 In the example shown, the lateral flow passage SPb is composed of a groove provided on a surface of the layer 31 facing the Z2 direction and a groove provided on a surface of the layer 32 facing the Z1 direction. In addition, although not shown in Figure 8 The second distribution supply flow passage SP2 is also composed in the same manner as the first distribution supply flow passage SP1, although not shown in

[0097] The bypass flow passage BP1 has a first portion BP1a, a second portion BP1b, and a third portion BP1c. The first portion BP1a and the second portion BP1b each extend in a direction along the Z axis and are composed of a hole that penetrates the layer 32. The third portion BP1c extends in a direction orthogonal to the Z axis and is provided between the layers 31 and 32. In Figure 8 In the example shown, the third portion BP1c is composed of a groove provided on a surface of the layer 31 facing the Z2 direction and a groove provided on a surface of the layer 32 facing the Z1 direction.

[0098] Similarly, the bypass flow passage BP2 has a first portion BP2a, a second portion BP2b, and a third portion BP2c. The first portion BP2a and the second portion BP2b each extend in a direction along the Z axis and are composed of a hole that penetrates the layer 32. The third portion BP2c extends in a direction orthogonal to the Z axis and is provided between the layers 31 and 32. In Figure 8 In the example shown, the third portion BP2c is composed of a groove provided on a surface of the layer 31 facing the Z2 direction and a groove provided on a surface of the layer 32 facing the Z1 direction.

[0099] 1-6. Flow path structure 11

[0100] Figure 9 is a plan view of the flow path structure 11. In Figure 9 , one example of the structure inside the flow path structure 11 when viewed in the Z2 direction is shown by a broken line. As Figure 9 indicated, the first supply flow path CC1, the second supply flow path CC2, the first discharge flow path CM1, the second discharge flow path CM2, the first filter chamber RF1, and the second filter chamber RF2 are provided inside the flow path structure 11.

[0101] The first supply flow path CC1 is a flow path for supplying the first ink introduced into the connection pipe 11a to the cradle 13 described above. Here, the first supply flow path CC1 communicates with the internal space of the connection pipe 11a via the first filter chamber RF1. The discharge port CE1 connected to the connection pipe 13a described above is communicated on the first supply flow path CC1.

[0102] The second supply flow path CC2 is a flow path for supplying the second ink introduced into the connection pipe 11b to the cradle 13 described above. Here, the second supply flow path CC2 communicates with the internal space of the connection pipe 11b via the second filter chamber RF2. The discharge port CE2 connected to the connection pipe 13b described above is communicated on the second supply flow path CC2.

[0103] The first discharge flow path CM1 is a flow path for discharging the first ink from the cradle 13 described above from the connection pipe 11c. The introduction port CI1 connected to the three connection pipes 13c described above is communicated on the first discharge flow path CM1.

[0104] The second discharge flow path CM2 is a flow path for discharging the second ink from the cradle 13 described above from the connection pipe 11d. The introduction port CI2 connected to the three connection pipes 13d described above is communicated on the second discharge flow path CM2.

[0105] Figure 10 is a plan view of the flow path structure 11. In Figure 9 , one example of the structure inside the flow path structure 11 when viewed in the Z2 direction is shown by a broken line. As Figure 10 indicated, the first supply flow path CC1, the second supply flow path CC2, the first discharge flow path CM1, the second discharge flow path CM2, the first filter chamber RF1, and the second filter chamber RF2 are provided inside the flow path structure 11.

[0106] As Figure 10 indicated, the flow path structure 11 is in a plate shape that expands in a direction perpendicular to the Z axis. The flow path structure 11 has the layers 21, 22, and 23, and the fixing member 24 and the filter 25 interposed between the layer 21 and the layer 22.

[0107] The layers 21, 22, and 23 are laminated in this order in the Z2 direction. The layers 21, 22, and 23 are, for example, each composed of a resin material, and are formed by injection molding. The layers 21, 22, and 23 are, for example, joined to each other by an adhesive. In addition, the thicknesses of the layers 21, 22, and 23 along the Z axis can be the same as each other or different from each other.

[0108] The recessed surface 21a, the introduction port 21b, and the groove 21c are provided on the layer 21. The recessed surface 21a is provided on a surface of the layer 21 facing the Z2 direction, and constitutes a part of a wall surface of the first filter chamber RF1. The recessed surface 21a is, for example, formed by injection molding. The recessed surface 21a is, for example, joined to the layer 21 by an adhesive. Figure 10 In the example shown, the recessed surface 21a is in a shape that continuously deepens toward the introduction port 21b. The introduction port 21b is a through-hole that is opened on the recessed surface 21a and communicates with the internal space of the connection pipe 11a. The introduction port 21b is, for example, formed by injection molding. The introduction port 21b is, for example, joined to the layer 21 by an adhesive. Figure 10 In the example shown, the connection pipe 11a is integrally constituted with the layer 21. Therefore, the connection pipe 11a is also composed of a resin material, like the layer 21. The groove 21c is provided on a surface of the layer 21 facing the Z2 direction along the outer periphery of the recessed surface 21a, and constitutes a space that accommodates a part of the fixing member 24 described later. The groove 21c can also function as a retreat portion of an adhesive.

[0109] In addition, the connection pipe 11a can also be constituted in a separate manner from the layer 21. In this case, the connection pipe 11a can also be composed of a metal material or the like, and is fixed to the layer 21 by an adhesive or the like. Furthermore, the groove 21c need only be provided as necessary, and can be omitted. Furthermore, like the connection pipe 11a, the connection pipes 11b to 11c can be integrally constituted with the layer 21 or constituted in a separate manner from the layer 21.

[0110] The recessed portion 22a, the groove 22b, the hole 22c, and the hole 22d are provided on the layer 22. The recessed portion 22a is provided on a surface of the layer 22 facing the Z1 direction, and constitutes a space that accommodates a part of the fixing member 24 described later. The groove 22b is provided on a surface of the layer 22 facing the Z2 direction, and constitutes a part of the first supply flow passage CC1. In the example shown, the recessed portion 22a is in a shape that continuously deepens toward the hole 22c. Figure 10 In the example shown, the first supply flow passage CC1 is in a shape that extends along the Y axis and has a portion in which the area of the X-Z plane narrows toward the Y2 direction. The hole 22c and the hole 22d are each a hole that is opened on the recessed portion 22a and the groove 22b and penetrates the layer 22. In the example shown, the hole 22c is connected to one end in the Y2 direction of the groove 22b. Figure 10 In the example shown, the hole 22c is connected to one end in the Y2 direction of the groove 22b. The hole 22d is connected to the groove 22b at a position in the Y1 direction with respect to the hole 22c.

[0111] A groove 23a is provided on the layer 23. The groove 23a is provided on a surface of the layer 23 facing the Zl direction, and constitutes a part of the first supply flow passage CC1. In Figure 10 In the example shown, the groove 23a has a shape extending along the Y axis. Also, although the first supply flow passage CC1 is constituted by the groove 22b of the layer 22 and the groove 23a of the layer 23 in the example shown, the first supply flow passage CC1 can be constituted by one of the groove 22b and the groove 23a. Figure 10 In the example shown, the first supply flow passage CC1 is constituted by the groove 22b of the layer 22 and the groove 23a of the layer 23, but the first supply flow passage CC1 can be constituted by one of the groove 22b and the groove 23a.

[0112] The fixing member 24 is a substantially plate-shaped member that fixes the filter 25 to at least one of the layers 21 and 22 and constitutes a part of a wall surface of the first filter chamber RF1. In Figure 10 In the example shown, the fixing member 24 is provided on the recess 22a described above. The fixing member 24 is constituted by, for example, a resin material, and is formed by injection molding. Here, the fixing member 24 is formed by insert molding using the filter 25 as an insert, so that the filter 25 can be fixed to the fixing member 24. Further, the fixing member 24 is fixed to at least one of the layers 21 and 22 by, for example, an adhesive.

[0113] Thus, by fixing the filter 25 to at least one of the layers 21 and 22 via the fixing member 24, it is possible to expand the range of selection of the structural material of the layers 21 and 22, or to reduce the case where an adhesive is unintentionally attached to the filter 25, as compared with a structure in which the filter 25 is directly fixed to at least one of the layers 21 and 22. Also, the constituent material of the fixing member 24 can be the same as or different from the constituent material of the layer 21 or the layer 22.

[0114] A bottom wall 24a, a frame portion 24b, a first discharge port 24c, and a second discharge port 24d are provided on the fixing member 24.

[0115] The bottom wall 24a is provided on a surface of the fixing member facing the Zl direction, and constitutes a part of a wall surface of the first filter chamber RF1. In Figure 10 In the example shown, the bottom wall 24a has a shape that continuously deepens toward the first discharge port 24c and the second discharge port 24d, respectively. The frame portion 24b is a ring-shaped wall portion along the outer periphery of the bottom wall 24a, and constitutes a side wall of the first filter chamber RF1. More specifically, a part of the inner peripheral surface of the frame portion 24b constitutes a side wall 24i of the downstream chamber RFb. In Figure 10In the illustrated example, a portion of the frame portion 24b is inserted into the groove 21c described above. By this insertion, the fixing member 24 is positioned with respect to the layer 21. Further, a gap is formed between the outer peripheral surface of the frame portion 24b and the recessed portion 22a. This gap can function as a retreat portion for an adhesive. The first discharge port 24c and the second discharge port 24d are holes that open in the bottom wall 24a and that pass through the fixing member 24. Further, the first discharge port 24c is connected to the hole 22c described above and constitutes the first flow passage C1 together with the hole 22c. The second discharge port 24d is connected to the hole 22d described above and constitutes the second flow passage C2 together with the hole 22d.

[0116] The filter 25 is a plate-shaped or sheet-shaped member that allows the passage of ink and captures foreign matter and the like mixed in the ink. The filter 25 is composed of, for example, metal fibers of oblique weave or flat weave. In addition, the filter 25 is not limited to a structure using metal fibers, and can be composed of, for example, resin fibers of nonwoven fabric or the like. The filter 25 is typically disposed in parallel with the nozzle face FN. However, the filter 25 can also be disposed so as to be inclined in a range of 0 degrees or more and 45 degrees or less with respect to the nozzle face FN.

[0117] The filter 25 is fixed to the frame portion 24b of the fixing member 24 described above. 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 with respect to the filter 25 and having the recessed face 21a as part of a wall face. The downstream chamber RFb is a space located in the Z2 direction with respect to the filter 25 and having the side wall 24i and the bottom wall 24a as part of a wall face.

[0118] Figure 11 Equivalent circuit diagram of a flow passage provided on the liquid discharge head 10. In Figure 11 Here, the flow passage resistance of each portion of the flow passage is shown.

[0119] As described above, the liquid discharge head 10 has a plurality of individual flow passages P, a common supply flow passage CF1, a common discharge flow passage CF2, and bypass flow passages BP1, BP2. The nozzles N are respectively provided on the plurality of individual flow passages P. The common supply flow passage CF1 supplies ink, which is an example of a "liquid", to the plurality of individual flow passages P. The common discharge flow passage CF2 discharges the ink from the plurality of individual flow passages P. The bypass flow passages BP1, BP2 bypass the plurality of individual flow passages P and connect the common supply flow passage CF1 and the common discharge flow passage CF2.

[0120] Here, the combined flow passage resistance Rs of the bypass flow passages BP1, BP2 and the plurality of individual flow passages P is larger than the flow passage resistance Rin of the common supply flow passage CF1 and larger than the flow passage resistance Rout of the common discharge flow passage CF2. Hereinafter, the effects obtained by the size relationship of the combined flow passage resistance Rs, the flow passage resistance Rin, and the flow passage resistance Rout will be described.

[0121] In the liquid discharge head 10, although the image quality can be improved by arranging the nozzles N at high density, the individual flow passages P also need to be densified in conjunction therewith. Therefore, for the improvement of the image quality, the cross-sectional area of the individual flow passages P has to be made small, and if it is assumed that the bypass flow passages BP1, BP2 are not provided in the liquid discharge head 10, the liquid will not be able to circulate sufficiently, and thus the tackiness of the ink cannot be properly eliminated.

[0122] In contrast to this, since the combined flow passage resistance Rs of the plurality of individual flow passages P and the bypass flow passages BP1, BP2 is reduced by providing the bypass flow passages BP1, BP2 in the liquid discharge head 10 and reducing the flow passage resistance RBP of the bypass flow passages BP1, BP2, if the overall flow rate of the ink circulated by the circulation mechanism 150 is increased to some extent, the tackiness elimination of the ink can be optimized. In addition, the flow passage resistance RBP is the combined flow passage resistance of the bypass flow passage BP1 and the bypass flow passage BP2.

[0123] However, if the flow passage resistance RBP of the bypass flow passages BP1, BP2 is made too small in order to emphasize the tackiness elimination of the ink, the combined flow passage resistance Rs of the plurality of individual flow passages P and the bypass flow passages BP1, BP2 becomes smaller than the flow passage resistance Rin of the common supply flow passage CF1 or the flow passage resistance Rout of the common discharge flow passage CF2. As a result, the flow passage resistance of the flow passages in the liquid discharge head 10 is determined by the flow passage resistance Rin of the common supply flow passage CF1 or the flow passage resistance Rout of the common discharge flow passage CF2. On the other hand, the common supply flow passage CF1 and the common discharge flow passage CF2 are connected to the plurality of individual flow passages P in common. Therefore, in general, each of the common supply flow passage CF1 and the common discharge flow passage CF2 needs to increase the flow rate to some extent, and thus the cross-sectional area has to be increased to some extent. Therefore, the flow passage resistance Rin and the flow passage resistance Rout are decreased to some extent. As described above, since the flow passage resistance Rin and the flow passage resistance Rout become the determining factors of the flow passage resistance of the flow passages in the liquid discharge head 10 when the flow passage resistance RBP of the bypass flow passages BP1, BP2 is made too small, as a result of decreasing the flow passage resistance Rin or the flow passage resistance Rout, there is a disadvantage that the amount of circulation of the ink by the circulation mechanism 150 increases, and thus the capacity of the pump used in the circulation mechanism 150 has to be increased or the number of pumps has to be increased.

[0124] On the other hand, while having the difficulty described above, if the flow passage resistance Rin and the flow passage resistance Rout can be increased respectively, the circulation flow of the ink realized by the circulation mechanism 150 itself can be reduced. However, since if so, the amount of the ink flowing in the individual flow passage P also becomes less, the effect of viscosity elimination of the ink cannot be obtained appropriately.

[0125] Therefore, in the liquid ejecting head 10, the flow passage resistances of the bypass flow passages BP1, BP2 are adjusted in such a manner that the resultant flow passage resistance Rs of the flow passage resistance of the resultant flow passage constituted by the bypass flow passages BP1, BP2 and the plurality of individual flow passages P is larger than each of the flow passage resistance Rin of the common supply flow passage CF1 and the flow passage resistance Rout of the common discharge flow passage CF2. Thus, since the flow passage resistances of the bypass flow passages BP1, BP2 are adjusted, the overall circulation flow of the ink realized by the circulation mechanism 150 does not need to be increased so much, and therefore the capacity of the pump used in the circulation mechanism 150 or the number of the pumps does not need to be increased. Further, since the flow in the individual flow passage P does not need to be reduced so much, the effect of viscosity elimination of the ink can also be obtained appropriately.

[0126] Here, it is preferable that the combined flow passage resistance Rs of the bypass flow passages BP1, BP2 and the plurality of individual flow passages P be 50% or more and 70% or less with respect to the combined flow passage resistance Rall of the bypass flow passages BP1, BP2, the plurality of individual flow passages P, the common supply flow passage CF1, and the common discharge flow passage CF2, that is, the flow passage resistance of the entire flow passage of the liquid ejecting head 10. As described above, in the case where the combined flow passage resistance Rs, which is the flow passage resistance of the combined flow passage constituted by the bypass flow passages BP1, BP2 and the plurality of individual flow passages P, is larger than each of the flow passage resistance Rin of the common supply flow passage CF1 and the flow passage resistance Rout of the common discharge flow passage CF2, if the investigation is made in units of 1%, the minimum value and the maximum value of the combined flow passage resistance Rs will be as described below. The minimum value of the combined flow passage resistance Rs is 34% with respect to the combined flow passage resistance Rall (the flow passage resistances of the common supply flow passage CF1 and the common discharge flow passage CF2 are 33% respectively). Further, the maximum value of the combined flow passage resistance Rs is 98% with respect to the combined flow passage resistance Rall (the flow passage resistances of the common supply flow passage CF1 and the common discharge flow passage CF2 are 1% respectively). That is, when the combined flow passage resistance Rs is 34% or more and 98% or less with respect to the combined flow passage resistance Rall, the effects of the present application can be obtained. However, in reality, in the entire flow passage of the liquid ejecting head 10, if the common supply flow passage CF1 or the common discharge flow passage CF2 becomes a decisive factor for the flow of ink, even if the flow passage resistances of the plurality of individual flow passages P and the bypass flow passages BP1, BP2 are adjusted as in each embodiment, it can be impossible to properly control the entire flow of ink. Therefore, it is preferable that the combined flow passage resistance of the common supply flow passage CF1 and the common discharge flow passage CF2 be less than 50% of the combined flow passage resistance Rall, or in other words, the combined flow passage resistance Rs be 50% or more of the combined flow passage resistance Rall. On the other hand, if the combined flow passage resistance Rs is too large, the flow of ink from the plurality of individual flow passages P and the bypass flow passages BP1, BP2 can be extremely restricted, and as a result, it can be impossible to sufficiently eliminate the viscosity of ink depending on the kind of ink. Specifically, if the combined flow passage resistance Rs is 70% or less of the combined flow passage resistance Rall, the viscosity of ink can be properly eliminated in various kinds of ink. That is, although it is necessary in the present application that the combined flow passage resistance Rs be 34% or more and 98% or less with respect to the combined flow passage resistance Rall, it is particularly preferable that the combined flow passage resistance Rs be 50% or more and 70% or less. This effect resulting from being 50% or more and 70% or less can be obtained in Examples 2, 3, 4, 5, 6, 12, 13, 14, and 15 among each of the examples in Table 1 described later. These examples correspond to the examples in which "A" is described in the "Others" column shown in Table 1.

[0127] Further, it is more preferable that the flow passage resistance RBP of the bypass passage BP1, BP2 be 25% or more and 55% or less with respect to the resultant flow passage resistance RP of the plurality of individual passages P. If the flow passage resistance RBP of the bypass passage BP1, BP2 is too small with respect to the resultant flow passage resistance RP of the plurality of individual passages P, there is a possibility that too much ink flows in the bypass passage BP1, BP2 compared to the individual passages P, and thus the entire flow rate has to be increased in order to remove the air bubbles mixed in the individual passages P. On the other hand, if the flow passage resistance RBP of the bypass passage BP1, BP2 is too large with respect to the resultant flow passage resistance RP of the plurality of individual passages P, the flow passage resistance of the individual passages P becomes relatively small, and thus the cross-sectional area of the individual passages P increases to some extent, and the density of the nozzles N decreases, and thus it can be impossible to obtain a satisfactory image quality. In order to properly balance the high density of the nozzles N and the reduction of the entire flow rate of the ink circulated by the circulation mechanism 150, it is preferable that the flow passage resistance RBP of the bypass passage BP1, BP2 be smaller than the resultant flow passage resistance RP of the plurality of individual passages P. This effect can be obtained in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 13, 14, and 15 among the examples in Table 1 described later. These examples correspond to the examples in which "B" is described in the "Others" column in Table 1. Further, in order to more properly balance the high density of the nozzles N and the reduction of the entire flow rate of the ink circulated by the circulation mechanism 150, it is more preferable that the flow passage resistance RBP of the bypass passage BP1, BP2 be 25% or more and 55% or less with respect to the resultant flow passage resistance RP of the plurality of individual passages P. This effect can be obtained in Examples 2, 3, 4, 5, 6, 7, 12, 13, 14, and 15 among the examples in Table 1 described later. These examples correspond to the examples in which "C" is described in the "Others" column in Table 1.

[0128] As described above, each of the plurality of individual passages P includes a pressure chamber C to which pressure is applied in order to eject ink from the nozzle N, an individual supply passage Ra1 that supplies ink to the pressure chamber C, and an individual discharge passage Ra2 that discharges ink from the pressure chamber C.

[0129] Here, it is preferable that the flow passage resistance RBP of the bypass passage BP1, BP2 be smaller than the resultant flow passage resistance RCa of the individual supply passages Ra1 included in the plurality of individual passages P. In this case, the entire flow rate of the ink circulated by the circulation mechanism 150 can be properly reduced.

[0130] Further, it is preferable that the flow passage resistance RBP of the bypass flow passages BP1, BP2 be smaller than the resultant flow passage resistance RCb of the plurality of individual discharge flow passages Ra2. In this case, the overall flow rate of the ink that is circulated through the circulation mechanism 150 can be appropriately reduced.

[0131] This effect resulting from making the flow passage resistance RBP of the bypass flow passages BP1, BP2 smaller than the resultant flow passage resistance RCa of the plurality of individual supply flow passages Ra1 and the resultant flow passage resistance RCb of the plurality of individual discharge flow passages Ra2 can be obtained in Embodiments 1, 2, 3, 4, 5, 6, 7, 12, 13, 14, and 15 among the examples in Table 1 described later. These embodiments correspond to the examples in which "D" is described in the "Others" column shown in Table 1.

[0132] Further, it is preferable that the flow passage resistance of each of the individual supply flow passages Ra1 included in the plurality of individual flow passages P be substantially equal to the flow passage resistance of each of the individual discharge flow passages Ra2 included in the plurality of individual flow passages P. If the flow passage resistances of the individual supply flow passages Ra1 and the individual discharge flow passages Ra2 are different, even if the piezoelectric element 14e is driven in the same manner, the flow (momentum) of the liquid can differ between the pressure chambers Ca and Cb during the period until reaching the nozzle. Thus, it can be necessary to adjust the driving of the piezoelectric element 14e to be different between the pressure chambers Ca and Cb. By making these flow passage resistances substantially equal, this adjustment can be omitted. This effect can be obtained in Embodiments 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 among the examples in Table 1 described later. These embodiments correspond to the examples in which "E" is described in the "Others" column shown in Table 1.

[0133] Further, although the magnitude relationship between the flow passage resistance Rin of the common supply flow passage CF1 and the flow passage resistance Rout of the common discharge flow passage CF2 is not particularly limited, it is preferable that the flow passage resistance Rin of the common supply flow passage CF1 be larger than the flow passage resistance Rout of the common discharge flow passage CF2. For example, in a case where the filter 25 that becomes an element of the flow passage resistance that increases the flow passage resistance is provided in the common supply flow passage CF1 to capture foreign matter that goes to the nozzle N as described above, it is easy to make the flow passage resistance Rin of the common supply flow passage CF1 large. On the other hand, since the common discharge flow passage CF2 is at the downstream side compared to the nozzle N, the effect of providing the filter 25 in the common discharge flow passage CF2 is lower than that of providing it in the common supply flow passage CF1, and it is more desirable to be able to reduce the cost and the like by not providing the filter 25. At this time, the flow passage resistance Rin is made larger than the flow passage resistance Rout by the presence or absence of the filter. This effect can be obtained in Embodiments 1, 2, 3, 5, 7, 8, 9, 10, and 11 among the embodiments in Table 1 described later. These embodiments correspond to examples in which "F" is described in the "Others" column shown in Table 1.

[0134] Further, the flow passage resistance RBP of the bypass flow passages BP1 and BP2 differs depending on the kind of ink used and the like, and although it is not particularly limited as long as the magnitude relationship of the flow passage resistance Rin, the flow passage resistance Rout, and the flow passage resistance RBP described above can be satisfied, it is preferable that, for example, in a case where the viscosity of the ink is 6.00 [m·Pa / s], the flow passage resistance RBP be 2.23 x 10 10 [N·s / m 5 ] or more and 6.69 x 10 10 [N·s / m 5 ] or less. When the flow passage resistance RBP is within this range, the bypass flow passages BP1 and BP2 that are suitable for a case where ordinary ink is used can be obtained.

[0135] Further, the flow passage resistance RBP of the bypass flow passages BP1 and BP2 differs depending on the kind of ink used and the like, and although it is not particularly limited as long as the magnitude relationship of the flow passage resistance Rin, the flow passage resistance Rout, and the flow passage resistance RBP described above can be satisfied, it is preferable that, for example, in a case where the viscosity of the ink is 6.00 [m·Pa / s], the flow passage resistance RBP be 2.23 x 10 10 [N·s / m 5 ] or more and 6.69 x 10 10 [N·s / m 5When the channel resistance Rjn is in such a range, the bypass channel BP1, BP2, and the individual channel P suitable for the case where ordinary ink is used can be obtained.

[0136] Further, the channel resistance Rjn of the common feed channel CF1 differs depending on the kind of ink used, etc., and although it is not particularly limited as long as the magnitude relation of the channel resistance Rjn, the channel resistance Rjn, and the channel resistance Rout described above can be satisfied, it is preferably, for example, 9.76 x 10 9 [N-s / m 5 ] or more and 2.93 x 10 10 [N-s / m 5 or less. When the channel resistance Rjn is in such a range, the common feed channel CF1 suitable for the case where ordinary ink is used can be obtained.

[0137] Further, the channel resistance Rout of the common discharge channel CF2 differs depending on the kind of ink used, etc., and although it is not particularly limited as long as the magnitude relation of the channel resistance Rjn, the channel resistance Rjn, and the channel resistance Rout described above can be satisfied, it is preferably, for example, 1.39 x 10 9 [N-s / m 5 ] or more and 4.18 x 10 9 [N-s / m 5 or less. When the channel resistance Rout is in such a range, the common discharge channel CF2 suitable for the case where ordinary ink is used 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 the Z1 direction or the Z2 direction which is an example of a "first direction", and is connected to the common feed channel CF1. The second portion BP1b extends along the Z1 direction or the Z2 direction, and is connected to the common discharge channel CF2. The third portion BP1c extends along a plane parallel to both the X1 direction or the X2 direction which is an example of a "second direction", and the Y1 direction or the Y2 direction which is an example of a "third direction", and is connected to the first portion BP1a and the second portion BP1b, respectively. Here, the "first direction" is a 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 flow path BP1, since the portions in which bending or curving occurs are provided between each of the first portion BP1a and the second portion BP1b and the third portion BP1c, it has an advantage that the flow path resistance is easily increased. Further, at least a part of the bypass flow paths BP1, BP2 can be provided on the holder 13 which is a member different from the head main body 14. In addition, as described above, the bypass flow path BP2 has a first portion BP2a, a second portion BP2b, and a third portion BP2c, and is configured in the same manner as the bypass flow path BP1, and thus has the same effect as the bypass flow path BP1.

[0140] Here, as described above, the third portion BP1c has a U-shaped form when viewed in the Z1 direction or the Z2 direction. In such a third portion BP1c of this form, it has an advantage that the flow path resistance is easily increased.

[0141] Further, it is preferable that the flow path resistance of each of the first portion BP1a and the second portion BP1b be larger than the flow path resistance of the third portion BP1c. Since the first portion BP1a and the second portion BP1b each extend along the Z1 direction or the Z2 direction which is the thickness direction of the holder 13, it is easier to reduce the cross-sectional area with good precision. Therefore, by making the flow path resistance of each of the first portion BP1a and the second portion BP1b larger than the flow path resistance of the third portion BP1c, it is possible to easily manufacture a bypass flow path BP1 of a desired flow path resistance.

[0142] As described above, the liquid discharge apparatus 100 described above has the liquid discharge head 10, and the control unit 120 which is an example of the "control section" that controls the discharge operation of the ink performed by the liquid discharge head 10.

[0143] In the present embodiment, the control unit 120 controls, in addition to the discharge operation of discharging the ink from the liquid discharge head 10, a recovery operation of recovering the state of the liquid discharge head 10, and a filling operation of filling the ink into the liquid discharge head 10. Here, the discharge operation is, for example, an operation of printing an image based on image information on the medium M by causing the liquid discharge head 10 to operate based on the image information. The recovery operation is, for example, an operation of causing the ink discharge characteristics realized by the liquid discharge head 10 to approach target characteristics by eliminating the thickening of the ink in the liquid discharge head 10 and the like by causing the circulation mechanism 150 to operate. The filling operation is, for example, an operation of filling the ink into the liquid discharge head 10 by causing the circulation mechanism 150 to operate at the initial use of the liquid discharge head 10.

[0144] Here, as described above, the liquid ejecting apparatus 100 has the 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 manner that the flow rate of the ink per unit time realized by the circulation mechanism 150 at the time of the recovery operation or the filling operation is more than the flow rate of the ink per unit time realized by the circulation mechanism 150 at the time of the ejecting operation. Hereinafter, the operation of the liquid ejecting apparatus 100 will be described.

[0145] Figure 12 A flowchart showing one example of the operation of the liquid ejecting apparatus 100 according to the embodiment. As shown in the flowchart, first, the control unit 120 determines whether or not an instruction of the ejecting operation is present in step S1. The instruction is given, for example, by the user's operation on an input device such as an operation panel not shown. Figure 12

[0146] In the case where the instruction of the ejecting operation is present, the control unit 120 sets the flow rate of the ink per unit time realized by the circulation mechanism 150 to the first flow rate in step S2.

[0147] Thereafter, the control unit 120 executes the ejecting operation in step S3. At the time of the execution of the ejecting operation, the control unit 120 controls the operation of the circulation mechanism 150 in such a manner that the first flow rate set in step S2 described above is realized. Here, from the viewpoint of realizing stable ejecting characteristics, it is preferable that the first flow rate be constant over the execution period of the ejecting operation.

[0148] On the other hand, in the case where the instruction of the ejecting operation is not present, or after the end of the ejecting operation, the control unit 120 determines whether or not an instruction of the recovery operation is present in step S4. The instruction is given, for example, by the user's operation on an input device such as an operation panel not shown.

[0149] In the case where the instruction of the recovery operation is present, the control unit 120 sets the flow rate of the ink per unit time realized by the circulation mechanism 150 to the second flow rate in step S5. The second flow rate is an amount larger than the first flow rate described above.

[0150] ​Thereafter, the control unit 120 implements a recovery operation in step S6. In performing this recovery operation, the control unit 120 controls the operation of the circulation mechanism 150 in such a manner that the second flow rate set in the aforementioned step S5 is attained. Further, this recovery operation is implemented over a predetermined period until the ejection characteristics of the ink implemented by the liquid ejection head 10 become the desired characteristics. Here, while the second flow rate need only be greater than the first flow rate, it is preferable that the ink not be ejected from the nozzles N, and further, from the viewpoint of preventing ejection of the ink from the nozzles N, it is preferable that the second flow rate be fixed over the period during which the recovery operation is performed.

[0151] On the other hand, in the case where the instruction of the recovery operation is not present, or after the end of the recovery operation, the control unit 120 judges the presence or absence of an instruction of a filling operation in step S7. This instruction is implemented, for example, by the user operating an unillustrated operation panel or the like.

[0152] In the case where the instruction of the filling operation is present, the control unit 120 sets the flow rate of the ink per unit time implemented by the circulation mechanism 150 to a third flow rate in step S8. This third flow rate is an amount greater than the aforementioned first flow rate. Here, while the third flow rate can be the same as or different from the second flow rate, it is preferable that it be equal to or greater than the second flow rate. In this case, it is possible to shorten the period required for the filling operation, or prevent the case where the ink leaks from the nozzles N when the recovery operation is performed.

[0153] Thereafter, the control unit 120 implements the filling operation in step S9. In performing this filling operation, the control unit 120 controls the operation of the circulation mechanism 150 in such a manner that the third flow rate set in the aforementioned step S8 is attained. Further, this filling operation is implemented over a predetermined period until a predetermined amount of ink is filled to the liquid ejection head 10. Here, the third flow rate need only be greater than the first flow rate, and it can be fixed over the period during which the filling operation is performed, or it can change.

[0154] On the other hand, in the case where the instruction of the filling operation is not present, or after the end of the filling operation, the control unit 120 judges the presence or absence of an end instruction in step S10. This end instruction is implemented, for example, by the user operating an unillustrated operation panel or the like.

[0155] The control unit 120 returns to the aforementioned step S1 in the case where the end instruction is not present, and on the other hand, ends the processing in the case where the end instruction is present.

[0156] As described above, the liquid ejecting apparatus 100 has the liquid ejecting head 10, the circulation mechanism 150, and the control unit 120 as an example of the "control section". The liquid ejecting head 10 has a plurality of individual flow paths P, a common supply flow path CF1, a common discharge flow path CF2, and bypass flow paths BP1, BP2. The nozzles N are respectively provided in the plurality of individual flow paths P. The common supply flow path CF1 supplies ink as an example of the "liquid" to the plurality of individual flow paths P. The common discharge flow path CF2 discharges the ink from the plurality of individual flow paths P. The bypass flow paths BP1, BP2 bypass the individual flow paths P and communicate the common supply flow path CF1 with the common discharge flow path CF2. The circulation mechanism 150 circulates the ink supplied from the common supply flow path CF1 in a manner that the ink passes through the plurality of individual flow paths P or the bypass flow paths BP1, BP2 and is discharged from the common discharge flow path CF2. The control unit 120 controls the operation of the circulation mechanism 150.

[0157] Here, the control unit 120 implements a process of setting a flow rate per unit time of the ink circulated by the circulation mechanism 150 to a first flow rate when performing an ejecting operation of ejecting the ink from the liquid ejecting head 10, and setting the flow rate per unit time of the ink circulated by the circulation mechanism 150 to a second flow rate that is larger than the first flow rate when performing a recovery operation of recovering the state of the liquid ejecting head 10. In addition, as described above, the ejecting operation is an operation of ejecting the ink from the liquid ejecting head 10. The recovery operation is an operation of recovering the state of the liquid ejecting head 10.

[0158] In the liquid ejecting apparatus described above, the flow rate per unit time of the ink circulated by the circulation mechanism 150 is larger when performing the recovery operation than when performing the ejecting operation. Therefore, when performing the ejecting operation, the circulation mechanism 150 can be appropriately operated to the extent necessary for the ink to be ejected from the liquid ejecting head 10, by thickening the ink or the like that has a large influence on the ejecting characteristics. On the other hand, when performing the recovery operation, the circulation mechanism 150 can be operated to the extent necessary for the state of the liquid ejecting head 10 to be recovered, by removing bubbles or the like. Thus, since it is only necessary to increase the flow rate of the ink only when necessary, it is not necessary to increase the number of pumps used in the circulation mechanism 150 or to increase the capacity of the pumps. As a result, it is possible to reduce thickening of the ink or removal of bubbles while achieving cost reduction of the liquid ejecting apparatus.

[0159] Further, the control unit 120 sets the flow rate per unit period of the ink supplied to the liquid discharge head 10 to a third flow rate that is larger than the first flow rate when the filling operation is performed. Thus, when the filling operation is performed, the circulation mechanism 150 can be caused to operate to the extent necessary to fill the liquid discharge head 10 with ink. In addition, as described above, the filling operation is an operation to fill the liquid discharge head 10 with ink.

[0160] Here, in a case where the third flow rate is equal to or larger than the second flow rate, the period required for the filling operation can be shortened, or a case where ink leaks from the nozzle N when the recovery operation is performed can be prevented.

[0161] 2. Modified Example

[0162] The above-described modes can be modified in various ways. Hereinafter, specific modified modes that can be applied to the above-described modes will be described. Two or more modes arbitrarily selected from the following examples can be appropriately combined within a range where they do not contradict each other.

[0163] 2-1. Modified Example 1

[0164] In the above-described modes, a structure in which the combined flow passage resistance Rs of the bypass flow passages BP1, BP2 and the plurality of individual flow passages P is larger than the flow passage resistance Rin of the common supply flow passage CF1 is exemplified, but is not limited to this structure. Thus, the combined flow passage resistance Rs of the bypass flow passages BP1, BP2 and the plurality of individual flow passages P can be equal to or smaller than the flow passage resistance Rin of the common supply flow passage CF1. However, as described above, it is preferable that the combined flow passage resistance Rs of the bypass flow passages BP1, BP2 and the plurality of individual flow passages P be larger than the flow passage resistance Rin of the common supply flow passage CF1.

[0165] 2-2. Modified Example 2

[0166] In the above-described modes, a structure in which the combined flow passage resistance Rs of the bypass flow passages BP1, BP2 and the plurality of individual flow passages P is larger than the flow passage resistance Rout of the common discharge flow passage CF2 is exemplified, but is not limited to this structure. Thus, the combined flow passage resistance Rs of the bypass flow passages BP1, BP2 and the plurality of individual flow passages P can be equal to or smaller than the flow passage resistance Rout of the common discharge flow passage CF2. However, as described above, it is preferable that the combined flow passage resistance Rs of the bypass flow passages BP1, BP2 and the plurality of individual flow passages P be larger than the flow passage resistance Rout of the common discharge flow passage CF2.

[0167] 2-3. Modified 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 flow passage resistance Rs of the bypass passage and the plurality of individual passages was 2.51 x 10 10 [N-s / m 5 ] The flow passage resistance Rjn of the common supply passage was 1.95 x 10 10 [N-s / m 5 ] The flow passage resistance Rout of the common discharge passage was 1.12 x 10 10 [N-s / m 5 ].

[0180] With respect to these flow passage resistances, each value was described on the basis of rounding off the first digit after the decimal point, in the case where the total value of the combined flow passage resistance Rs, the flow passage resistance Rjn, and the flow passage resistance Rout of the common discharge passage was set to 100. The combined flow passage resistance RCa of the plurality of individual supply passages was 115. The combined flow passage resistance RCb of the plurality of individual discharge passages was 115. The flow passage resistance RBP of the bypass passage was 56. The combined flow passage resistance Rs of the bypass passage and the plurality of individual passages was 45. The flow passage resistance Rjn of the common supply passage was 35. The flow passage resistance Rout of the common discharge passage was 20.

[0181] Here, the combined flow passage resistance RCa+RCb of the combined flow passage resistance of the plurality of individual supply passages RCa and the combined flow passage resistance of the plurality of individual discharge passages RCb was 229. In addition, since the individual passage P is constituted by the individual supply passage and the individual discharge passage, the combined flow passage resistance RCa+RCb is equal to the combined flow passage resistance RP of the plurality of individual passages P. As a result, the flow passage resistance RBP=56 of the bypass passage BP1, BP2 is smaller than the combined flow passage resistance RP=229 of the individual passage P.

[0182] Also, the ratio RBP / (RCa+RCb) of the flow passage resistance RBP of the bypass passage BP1, BP2 to the combined flow passage resistance RP of the plurality of individual passages P was 0.24. As a result, the flow passage resistance RBP of the bypass passage BP1, BP2 was 25% smaller than the combined flow passage resistance RP of the individual passage P.

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

[0184] Examples 2 to 15 and Reference Examples 1 to 12 were manufactured in the same manner as in Example 1 described above, except that the combined flow passage resistance RCa, the combined flow passage resistance RCb, the flow passage resistance RBP, the combined flow passage resistance Rs, the flow passage resistance Rjn, and the flow passage resistance Rout were set in the manner shown in Table 1.

[0185] Table 1 Table 1

[0186]

[0187] B. Evaluation

[0188] B-1. Evaluation of flow rate

[0189] The flow rate of ink for the entire flow path of the liquid ejection head was evaluated in accordance with the following criteria.

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

[0191] B: The ink flow rate was slightly excessive.

[0192] C: The ink flow rate was excessive.

[0193] The evaluation results are as described in the "Overall flow rate" column of Table 1.

[0194] B-2. Evaluation of tackiness

[0195] The tackiness of ink in the vicinity of the nozzle of the liquid ejection head was evaluated in accordance with the following criteria.

[0196] A: No tackiness occurred.

[0197] B: There was a tendency toward tackiness, but no problems in actual use.

[0198] C: Tackiness occurred that was problematic in actual use.

[0199] The evaluation results are as described in the "Tackiness" column of Table 1.

[0200] B-3. Comprehensive evaluation

[0201] A comprehensive evaluation of the evaluations of flow rate and tackiness described above was performed in accordance with the following criteria.

[0202] A: Both the evaluations of flow rate and tackiness were not problematic.

[0203] B: At least one of the evaluations of flow rate and tackiness was problematic.

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

[0205] B-4. Other evaluations

[0206] Other evaluations of each example were performed in accordance with the following criteria.

[0207] A: The balance between the tackiness and flow rate of ink was particularly excellent.

[0208] B: The balance between the nozzle density and the overall flow rate of ink was appropriate.

[0209] C: The balance between the nozzle density and the overall flow rate of ink is more appropriate.

[0210] D: The overall flow rate of ink is particularly small.

[0211] E: The deviation between the two pressure chambers is reduced.

[0212] F: The balance between the foreign matter capturing property and cost reduction is achieved.

[0213] The evaluation results are as described in the "Others" column of Table 1. In addition, there are cases where multiple criteria are satisfied in the present evaluation, and the more the number of satisfied criteria, the more excellent the evaluation.

[0214] As is clear from the results shown in Table 1, each of the examples achieved an excellent result compared with each of the reference examples. In addition, the same results were achieved for the ejection operation, the recovery operation, and the filling operation, respectively. Here, it was confirmed for the recovery operation and the filling operation, respectively, that when the flow rate of ink per unit time was made larger than that of the ejection operation, the bubbles in the flow path could be appropriately removed.

[0215] Explanation of Symbols

[0216] 10…liquid ejection head; 11…flow passage structure; 11a…connection pipe; 11b…connection pipe; 11c…connection pipe; 11d…connection pipe; 11e…hole; 12…wiring substrate; 12a…hole; 12b…opening portion; 12c…connector; 13…holder; 13a…connection pipe; 13b…connection pipe; 13c…connection pipe; 13d…connection pipe; 13e…wiring hole; 13f…recess; 14…head main body; 14_1…head main body; 14_2…head main body; 14_3…head main body; 14_4…head main body; 14_5…head main body; 14_6…head main body; 14a…nozzle substrate; 14b…flow passage substrate; 14c…pressure chamber substrate; 14d…vibration plate; 14e…piezoelectric element; 14f…case; 14g…protective plate; 14h…wiring substrate; 14i…drive circuit; 14j…vibration absorbing body; 15…fixing plate; 15a…opening portion; 16…base; 16a…main body; 16b…collective substrate; 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 member; 24a…bottom wall; 24b…frame portion; 24c…first discharge port; 24d…second discharge port; 24i…side wall; 25…filter; 31…layer; 32…layer; 41…support body; 41a…mounting hole; 100…liquid ejection apparatus; 110…liquid container; 120…control unit (control section); 130…transport mechanism; 140…liquid ejection module; 150…circulation mechanism; BP1…bypass flow passage; BP1a…first portion; BP1b…second portion; BP1c…third portion; BP2…bypass flow passage; BP2a…first portion; BP2b…second portion; BP2c…third portion; C…pressure chamber; C1…first flow passage; C2…second flow passage; CC…supply flow passage; CC1…first supply flow passage; CC2…second supply flow passage; CE1…discharge port; CE2…discharge port; CF1…common supply flow passage; CF2…common discharge flow passage; CI1…inlet; CI2…inlet; CM…discharge flow passage; CM1…first discharge flow passage; CM2…second discharge flow passage; Ca…pressure chamber; Cb…pressure chamber; Com…drive signal; DM…direction; DN…arrangement direction; DS…individual discharge flow passage; DS1…first individual discharge flow passage; DS2…second individual discharge flow passage; FN…nozzle face; IO1…supply port; IO2…discharge port; IO3a…discharge port; IO3b…discharge port; IO4a…inlet; IO4b…inlet; Ln…nozzle row; M…medium; N…nozzle; Na1…first communication flow passage; Na2…second communication flow passage; Nf…nozzle flow passage; P…individual flow passage; R1…first common liquid chamber; R2…second common liquid chamber; RBP…flow passage resistance; RCa…combined flow passage resistance;RCb... synthetic flow passage resistance; RF1... first filter chamber; RF2... second filter chamber; RFa... upstream chamber; RFb... downstream chamber; RP... synthetic flow passage resistance; Ra1... separate supply flow passage; Ra2... separate discharge flow passage; Rm... flow passage resistance; Rout... flow passage resistance; Rs... synthetic flow passage resistance; S1... step; S10... step; S2... step; S3... step; S4... step; S5... step; S6... step; S7... step; S8... step; S9... step; SP... distribution supply flow passage; SP1... first distribution supply flow passage; SP2... second distribution supply flow passage; SPa... vertical flow passage; SPb... horizontal flow passage.

Claims

1. A liquid discharge apparatus characterized by comprising: has: a liquid ejection head having a plurality of individual flow channels provided with nozzles, a common supply flow channel that supplies liquid to the plurality of individual flow channels, a common discharge flow channel that discharges 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 and the common discharge flow channel; a circulation mechanism that circulates liquid supplied from the common supply flow channel through the plurality of individual flow channels or the bypass flow channel to be discharged from the common discharge flow channel; a control section that controls the operation of the circulation mechanism, the control section sets the flow rate per unit time of liquid circulated by the circulation mechanism to a first flow rate when performing an ejection operation of ejecting liquid from the liquid ejection head, and sets the flow rate per unit time of liquid circulated by the circulation mechanism to a second flow rate that is larger than the first flow rate when performing a recovery operation of recovering the state of the liquid ejection head, the control section sets the flow rate per unit time of liquid supplied to the liquid ejection head to a third flow rate that is equal to or larger than the second flow rate when performing a filling operation of filling the liquid ejection head with liquid.

2. The liquid ejection apparatus according to claim 1, wherein the combined flow channel resistance of the bypass flow channel and the plurality of 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.

3. The liquid ejection apparatus according to claim 1, wherein the flow channel resistance of the bypass flow channel is smaller than the combined flow channel resistance of the plurality of individual flow channels.

4. The liquid ejection apparatus according to claim 1, wherein when a direction in which liquid is ejected from the nozzles is set as a first direction, a direction orthogonal to the first direction is set as a second direction, and a direction orthogonal to both the first direction and the second direction is set as a third direction, the bypass flow channel has a first portion that extends along the first direction and is connected to the common supply flow channel, a second portion that extends along the first direction and is connected to the common discharge flow channel, and a third portion that extends along a plane parallel to both the second direction and the third direction and is connected to the first portion and the second portion, respectively.

5. A liquid discharge apparatus characterized by comprising: has: a liquid ejection head having a plurality of individual flow channels provided with nozzles, a common supply flow channel that supplies liquid to the plurality of individual flow channels, a common discharge flow channel that discharges 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 and the common discharge flow channel; a circulation mechanism that circulates liquid supplied from the common supply flow channel through the plurality of individual flow channels or the bypass flow channel to be discharged from the common discharge flow channel; a control section that controls the operation of the circulation mechanism, the control section sets the flow rate per unit time of liquid circulated by the circulation mechanism to a first flow rate when performing an ejection operation of ejecting liquid from the liquid ejection head, and sets the flow rate per unit time of liquid circulated by the circulation mechanism to a second flow rate that is larger than the first flow rate when performing a recovery operation of recovering the state of the liquid ejection head, the control section sets the flow rate per unit time of liquid supplied to the liquid ejection head to a third flow rate that is equal to or larger than the second flow rate when performing a filling operation of filling the liquid ejection head with liquid. The bypass flow passage has a first portion, a second portion, and a third portion, when a direction in which liquid is ejected from the nozzle is set as a first direction, a direction orthogonal to the first direction is set as a second direction, and a direction orthogonal to both the first direction and the second direction is set as a third direction, the first portion extends along the first direction and is connected to the common supply flow passage, the second portion extends along the first direction and is connected to the common discharge flow passage, and the third portion extends along a plane parallel to both the second direction and the third direction and is connected to the first portion and the second portion, respectively, The third portion has a U shape when viewed in the first direction, The control section sets a flow rate per unit time of liquid circulated by the circulation mechanism to a first flow rate when performing an ejection operation of ejecting liquid from the liquid ejection head, and sets the flow rate per unit time of liquid circulated by the circulation mechanism to a second flow rate larger than the first flow rate when performing a recovery operation of recovering a state of the liquid ejection head.

6. A liquid discharge apparatus characterized by comprising: Having: A liquid ejection head having a plurality of individual flow passages provided with nozzles, a common supply flow passage that supplies liquid to the plurality of individual flow passages, a common discharge flow passage that discharges liquid from the plurality of individual flow passages, and a bypass flow passage that bypasses the plurality of individual flow passages and connects the common supply flow passage and the common discharge flow passage; A circulation mechanism that circulates liquid in a manner that liquid supplied from the common supply flow passage is discharged from the common discharge flow passage through the plurality of individual flow passages or the bypass flow passage; A control section that controls an operation of the circulation mechanism, The bypass flow passage has a first portion, a second portion, and a third portion, when a direction in which liquid is ejected from the nozzle is set as a first direction, a direction orthogonal to the first direction is set as a second direction, and a direction orthogonal to both the first direction and the second direction is set as a third direction, the first portion extends along the first direction and is connected to the common supply flow passage, the second portion extends along the first direction and is connected to the common discharge flow passage, and the third portion extends along a plane parallel to both the second direction and the third direction and is connected to the first portion and the second portion, respectively, The first portion and the second portion each have a larger flow passage resistance than the third portion, The control section sets a flow rate per unit time of liquid circulated by the circulation mechanism to a first flow rate when performing an ejection operation of ejecting liquid from the liquid ejection head, and sets the flow rate per unit time of liquid circulated by the circulation mechanism to a second flow rate larger than the first flow rate when performing a recovery operation of recovering a state of the liquid ejection head.

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