Liquid ejection device and liquid ejection method

Abstract

To enable air bubbles to be discharged from a common liquid chamber.SOLUTION: A liquid jet device includes: a liquid jet head having a jetting surface which jets a liquid; a tank in which the liquid to be supplied to the liquid jet head is stored; a circulation mechanism which performs a circulation operation for circulating the liquid between the liquid jet head and the tank; and a control unit which controls the circulation mechanism. The control unit causes a recording operation to be performed by the liquid jet head in a first attitude at which the jetting surface intersects with a horizontal surface and causes the circulation operation to be performed at a second attitude at which an angle made between the jetting surface and the horizontal surface is smaller than that of the first attitude.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection apparatus and a liquid ejection method. [Background technology]

[0002] For example, a liquid ejection device includes a plurality of head chips that eject liquid. The head chips have a common liquid chamber that communicates with a plurality of nozzles. The liquid ejection device includes a circulation flow path that circulates liquid that is not discharged from the nozzles. After being discharged from the common liquid chamber, the liquid that is not discharged from the nozzles passes through a flow path outside the head chip and is supplied back into the common liquid chamber. In the liquid ejection device described in Patent Document 1, a plurality of head chips are arranged so that the flow directions of liquid in the common liquid chamber of two adjacent head chips are opposite to each other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-49874 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, there is a liquid ejection device that performs a recording operation by ejecting liquid from the nozzles, with a head chip positioned so that the nozzle surface, on which multiple nozzles are provided, intersects with a horizontal plane. When the head chip is positioned in this manner and liquid is circulated through a common liquid chamber, the direction of the liquid flow in the common liquid chamber may be opposite to the direction of gravity. When the direction of the liquid flow in the common liquid chamber is opposite to the direction of gravity, the direction of the buoyancy acting on the air bubbles and the direction of the liquid flow are opposite, making it difficult for the air bubbles to be expelled from the common liquid chamber. The presence of air bubbles in the common liquid chamber poses a problem of affecting the liquid ejection from the nozzles during subsequent recording operations. [Means for solving the problem]

[0005] A liquid ejection device according to one aspect of the present invention comprises a liquid ejection head having an ejection surface for ejecting liquid, a tank for storing liquid to be supplied to the liquid ejection head, a circulation mechanism for performing a circulation operation to circulate the liquid between the liquid ejection head and the tank, and a control unit for controlling the circulation mechanism, wherein the control unit performs a recording operation using the liquid ejection head in a first position in which the ejection surface intersects with a horizontal plane, and performs the circulation operation in a second position in which the angle formed between the ejection surface and the horizontal plane is smaller than the first position.

[0006] A liquid ejection method according to one aspect of the present invention includes supplying liquid from a tank that stores the liquid to a liquid ejection head and ejecting the liquid from the ejection surface of the liquid ejection head to perform a recording operation, and performing a circulation operation to circulate the liquid between the liquid ejection head and the tank, wherein performing the recording operation involves performing the recording operation using the liquid ejection head in a first position in which the ejection surface intersects with a horizontal plane, and performing the circulation operation involves performing the circulation operation in a second position in which the angle formed between the ejection surface and the horizontal plane is smaller than the first position. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram illustrating a liquid ejecting apparatus according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram illustrating an ink flow path in the liquid ejecting apparatus. [Figure 3] FIG. 2 is a schematic diagram showing a common liquid chamber, a pressure chamber, and a nozzle. [Figure 4] FIG. 2 is a schematic diagram showing an arrangement of a plurality of head chips. [Figure 5] FIG. 2 is a perspective view illustrating a plurality of liquid jet heads. [Figure 6] FIG. 2 is an exploded perspective view showing the liquid jet head. [Figure 7] FIG. 2 is a cross-sectional view showing a head chip. [Figure 8] 3A and 3B are schematic diagrams illustrating a first attitude and a second attitude of the liquid jet head. [Figure 9] FIG. 2 is a side view showing the head chip in a first position. [Figure 10] FIG. 10 is a side view showing the head chip in the second position. [Figure 11] 10 is a side view showing a first attitude of a head chip according to Modification 1. FIG. [Figure 12] 10 is a side view showing a second attitude of the head chip according to Modification 2. FIG. [Figure 13] FIG. 10 is a bottom view illustrating a liquid jet head according to a second embodiment. [Figure 14] 10 is a schematic diagram showing an ink flow path in a liquid ejecting device according to a third embodiment. FIG. [Figure 15] FIG. 10 is a side view showing a first attitude of the head chip according to the fourth embodiment. [Figure 16] FIG. 10 is a side view showing a second attitude of the head chip according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, in each drawing, the dimensions and scale of each part may differ appropriately from those in reality. Furthermore, the embodiments described below are preferred specific examples of the present invention, and therefore various technically preferable limitations are applied, but the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description to the effect that the present invention is limited.

[0009] In the following description, the three mutually intersecting directions may be referred to as the X-axis direction, the Y-axis direction, and the Z-axis direction. The X-axis direction includes the X1 direction and the X2 direction, which are opposite directions. The Y-axis direction includes the Y1 direction and the Y2 direction, which are opposite directions. The Z-axis direction includes the Z1 direction and the Z2 direction, which are opposite directions. The X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The Z1 direction is along the ejection direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are based on the attitude of the liquid jet head 10. As will be described later, the X-axis direction, the Y-axis direction, and the Z-axis direction may change with respect to the gravity direction G1 depending on a change in the attitude of the liquid jet head 10.

[0010] In each figure, arrows indicate the X-axis, Y-axis, and Z-axis directions. However, when the posture of the liquid jet head 10 changes, the X-axis, Y-axis, and Z-axis directions may not match the arrangement of components other than the liquid jet head 10. Also, in schematic diagrams such as Figures 1 and 2, the arrangement may not match the actual arrangement. For example, in Figure 2, multiple head chips 20 are shown spaced apart in the Y-axis direction, but as shown in Figure 4, the multiple head chips 20 partially overlap when viewed in the X-axis direction. Other figures are also shown schematically, and may have shapes that differ from the actual ones. Furthermore, the positional relationships of the components may not completely match the actual ones.

[0011] FIG. 1 is a schematic diagram showing a liquid ejection device 1 according to a first embodiment. FIG. 2 is a schematic diagram showing ink flow paths in the liquid ejection device 1. The liquid ejection device 1 is an inkjet printing device that ejects ink, which is an example of a "liquid," as ink droplets onto a medium PA. The liquid ejection device 1 is, for example, a serial printing device. A liquid ejection head 10 ejects ink toward the medium PA while moving in the width direction of the medium PA. The medium PA is typically printing paper. Note that the medium PA is not limited to printing paper and may be a printing target made of any material, such as a resin film or fabric.

[0012] The liquid ejection device 1 includes multiple liquid containers 2, a medium transport mechanism 4, a carriage 5, a carriage transport mechanism 6, a control unit 30, and multiple liquid ejection heads 10. The liquid ejection device 1 includes a circulation mechanism 110. The liquid ejection device 1 may include one liquid ejection head 10 or multiple liquid ejection heads 10. The liquid ejection device 1 can perform a recording operation in which ink is ejected onto the medium PA to adhere to the medium PA. The liquid ejection device 1 can perform a maintenance operation. The maintenance operation includes an operation required to properly eject ink during the recording operation. The maintenance operation includes an operation for removing air bubbles from the ink. The maintenance operation may also include an operation for maintaining the viscosity of the ink at an appropriate level and an operation for maintaining the ejection direction of the ink at an appropriate level.

[0013] The control unit 30 controls the operation of each element of the liquid ejection device 1. The control unit 30 includes, for example, a processing circuit such as a CPU or FPGA, and a storage circuit such as a semiconductor memory. Various programs and data are stored in the storage circuit. The processing circuit executes the programs and uses the data as appropriate to realize various controls. CPU is an abbreviation for Central Processing Unit. FPGA is an abbreviation for Field Programmable Gate Array.

[0014] The medium transport mechanism 4 is controlled by the control unit 30 and transports the medium PA in the transport direction DM. When printing is performed by ejecting ink from the liquid jet head 10 in a printing device, the positional relationship between the transport direction DM of the medium PA and the ejection surface F1 of the liquid jet head 10 is well known. When printing is performed by ejecting ink from the liquid jet head 10, the transport direction DM may be parallel or approximately parallel to the Y-axis direction. The attitude of the liquid jet head 10 changes, and the Y-axis direction also changes along with the attitude of the liquid jet head 10. The medium transport mechanism 4 includes a long transport roller that extends along the width direction of the medium PA and a motor that rotates the transport roller. Note that the medium transport mechanism 4 is not limited to a configuration using a transport roller, and may be configured, for example, to use a drum or endless belt that transports the medium PA while adsorbed to its outer peripheral surface by electrostatic force or the like. The carriage 5 carries multiple liquid jet heads 10.

[0015] The liquid container 2 stores ink. Specific examples of the liquid container 2 include a cartridge that is detachable from the liquid ejecting device 1, a bag-shaped ink pack made of flexible film, and an ink tank that can be refilled with ink. The type of ink stored in the liquid container 2 is arbitrary.

[0016] As shown in FIG. 2, the liquid ejection device 1 includes a circulation mechanism 110. The circulation mechanism 110 includes a sub-tank 111, a pump 112, a temperature adjustment unit 113, an ink supply flow path 114, and an ink discharge flow path 115. The circulation mechanism 110 recovers ink that has not been ejected from the nozzles N of the liquid ejection head 10 and supplies it again to the liquid ejection head 10. The sub-tank 111 is a tank that temporarily stores ink. The sub-tank 111 is connected to a liquid container 2. Ink is supplied to the sub-tank 111 from the liquid container 2. Note that in the flow path through which ink flows, the terms "upstream" and "downstream" may be used relative to the liquid ejection head 10. Specifically, the portion from the liquid jet head 10 to the sub-tank 111 where ink flows from the sub-tank 111 to the liquid jet head 10 during the circulation operation described below is defined as upstream of the liquid jet head 10, and the portion where ink flows from the liquid jet head 10 to the sub-tank 111 is defined as downstream of the liquid jet head 10.

[0017] The sub-tank 111 is provided with a pressure adjusting section 111b. The pressure adjusting section 111b is, for example, a compressor, and can adjust the pressure inside the sub-tank 111. The pressure adjusting section 111b can make the pressure inside the sub-tank 111 negative.

[0018] The ink supply flow path 114 is a flow path that supplies ink in the subtank 111 to the liquid jet head 10. The ink supply flow path 114 includes, for example, a flow path member in which a groove, a recess, a through-hole, etc. is formed, a pipe, a tube, etc. The ink supply flow path 114 includes a flow path provided upstream of the liquid jet head 10.

[0019] The pump 112 is provided in the ink supply flow path 114 and is a pump for supplying ink in the subtank 111 to the liquid ejection head 10. The pump 112 may be, for example, a tube pump. The pump 112 may also be other pumps, such as a syringe pump or a diaphragm pump.

[0020] The temperature adjustment unit 113 is connected to the ink supply flow path 114 and adjusts the temperature of the ink. The temperature adjustment unit 113 is disposed, for example, downstream of the pump 112. For example, the temperature adjustment unit 113 includes a tank for temporarily storing ink and a heater for heating the temperature of the ink in the tank. The ink whose temperature has been adjusted by the temperature adjustment unit 113 is supplied to the liquid jet head 10. The heater of the temperature adjustment unit 113 may be configured to be controlled by the control unit 30 based on information detected by a temperature sensor 135, which will be described later, for example.

[0021] The ink flow path within the liquid jet head 10 will be described later. The ink discharge flow path 115 is a flow path that discharges ink within the liquid jet head 10 to the subtank 111. The ink discharge flow path 115 includes, for example, a flow path member in which a groove, a recess, a through-hole, etc. are formed, a pipe, a tube, etc. The ink discharge flow path 115 includes a flow path provided downstream of the liquid jet head 10.

[0022] Next, the flow of ink inside the liquid jet head 10 will be described. The liquid jet head 10 includes a plurality of head chips 20. Each head chip 20 is provided with a plurality of nozzles N. The nozzles N are illustrated in FIGS. 3 and 4. The plurality of head chips 20 include head chips 20A, 20B, 20C, and 20D. The arrangement of the plurality of head chips 20A, 20B, 20C, and 20D will be described later. When there is no need to distinguish between the plurality of head chips 20A, 20B, 20C, and 20D, they may be referred to as head chips 20.

[0023] Head chip 20A is provided with a common liquid chamber RA. Head chip 20B is provided with a common liquid chamber RB. Head chip 20C is provided with a common liquid chamber RC. Head chip 20D is provided with a common liquid chamber RD. When the common liquid chambers RA to RD are not to be distinguished, they may be referred to as common liquid chamber R.

[0024] As shown in FIG. 3, the multiple nozzles N communicate with a common liquid chamber R. The common liquid chamber R extends in the longitudinal direction of the head chip 20. The head chip 20 is provided with an ink supply port 46 for supplying ink to the common liquid chamber R and an ink discharge port 47 for discharging ink from the common liquid chamber R. As shown in FIG. 2, the head chip 20A is provided with an ink supply port 46A and an ink discharge port 47A. The head chip 20B is provided with an ink supply port 46B and an ink discharge port 47B. The head chip 20C is provided with an ink supply port 46C and an ink discharge port 47C. The head chip 20D is provided with an ink supply port 46D and an ink discharge port 47D. When the ink supply ports 46A to 46D are not distinguished, they may be referred to as ink supply port 46. When the ink discharge ports 47A to 47D are not distinguished, they may be referred to as ink discharge port 47.

[0025] The liquid jet head 10 includes a flow path 116, flow paths 117A to 117D, flow paths 118A to 118D, and a flow path 119. The liquid jet head 10 also includes a temperature sensor 135 that detects information related to the temperature of ink flowing through the flow paths in the liquid jet head 10, filters 136A to 136D, and a check valve 137.

[0026] Flow path 116 and flow paths 117A to 117D are connected to ink supply flow path 114. Flow path 116 and flow paths 117A to 117D are flow paths that supply ink to a plurality of head chips 20A to 20D. Flow paths 117A to 117D are flow paths branched off from flow path 116.

[0027] Flow path 117A is connected to ink supply port 46A of head chip 20A. Flow path 117B is connected to ink supply port 46B of head chip 20B. Flow path 117C is connected to ink supply port 46C of head chip 20C. Flow path 117D is connected to ink supply port 46D of head chip 20D.

[0028] The flow path 116 and the flow paths 117A to 117D include, for example, flow path members in which grooves, recesses, through-holes, etc. are formed, as well as pipes, tubes, etc. The ink supplied to the liquid jet head 10 flows through the flow path 116 and into each of the flow paths 117A to 117D.

[0029] The ink in flow path 117A is supplied to a common liquid chamber RA of head chip 20A. The ink in flow path 117B is supplied to a common liquid chamber RB of head chip 20B. The ink in flow path 117C is supplied to a common liquid chamber RC of head chip 20C. The ink in flow path 117D is supplied to a common liquid chamber RD of head chip 20D.

[0030] FIG. 3 is a schematic diagram showing a common liquid chamber R, pressure chambers C, and nozzles N. FIG. 3 shows the arrangement of the common liquid chamber R, pressure chambers C, and nozzles N when viewed in the Z1 direction. Also, FIG. 3 omits illustration of some of the multiple pressure chambers C and nozzles N. The head chip 20 has a common liquid chamber R, pressure chambers C, and nozzles N. The head chip 20 has multiple pressure chambers C lined up in the Y-axis direction. The multiple nozzles N are each connected to multiple pressure chambers C. The common liquid chamber R is connected to multiple pressure chambers C. The common liquid chamber R extends in the Y-axis direction.

[0031] An ink supply port 46 and an ink discharge port 47 are connected to the common liquid chamber R. Ink supplied to the head chip 20 passes through the ink supply port 46 and flows into the common liquid chamber R. The ink in the common liquid chamber R is supplied into multiple pressure chambers C. The ink in the pressure chambers C is ejected from the nozzles N. Ink that is not discharged from the nozzles N flows through the common liquid chamber R and is discharged from the ink discharge port 47. The ink in the common liquid chamber R flows in the Y-axis direction, from the ink supply port 46 toward the ink discharge port 47.

[0032] Ink discharged from common liquid chamber RA of head chip 20A flows through flow path 118A and into flow path 119. Ink discharged from common liquid chamber RB of head chip 20B flows through flow path 118B and into flow path 119. Ink discharged from common liquid chamber RC of head chip 20C flows through flow path 118C and into flow path 119. Ink discharged from common liquid chamber RD of head chip 20D flows through flow path 118D and into flow path 119. The ink flows in flow paths 118A to 118D are joined together.

[0033] A check valve 137 is connected to the flow path 119. The check valve 137 prevents the ink from flowing backward from the flow path 119 to the flow paths 118A to 118D. The ink in the flow path 119 is discharged to the outside of the liquid jet head 10. The ink in the flow path 119 flows through the ink discharge flow path 115 and into the sub-tank 111. The ink discharged from the liquid jet head 10 is collected in the sub-tank 111. The ink in the sub-tank 111 flows through the ink supply flow path 114 and is supplied to the liquid jet head 10. In this manner, the ink is circulated.

[0034] Next, the liquid jet head 10 will be described. Fig. 5 is a perspective view showing a plurality of liquid jet heads 10. Fig. 6 is an exploded perspective view showing the liquid jet head 10. As described above, the plurality of liquid jet heads 10 are mounted on the carriage 5. As shown in Fig. 6, the liquid jet head 10 includes a fixing plate 11, a plurality of head chips 20 each provided with a nozzle N, a holder 13 that holds the fixing plate 11 and the head chips 20, a flow path structure 14 that forms an ink flow path, a relay substrate 15 arranged on top of the flow path structure 14, a connector 16 provided on the relay substrate 15, and an upper cover 17.

[0035] The fixed plate 11 constitutes the bottom surface of the liquid jet head 10. The fixed plate 11 has openings 11a formed therein for exposing the nozzles N of the head chip 20.

[0036] The multiple head chips 20 are arranged at the bottom of the liquid jet head 10 and are held by a holder 13. The head chip 20 is provided with multiple nozzles N that eject liquid. The multiple nozzles N are aligned in the Y-axis direction to form a nozzle row NL. Note that the size, number, positional relationship, etc. of the nozzles N shown in the drawing are not the same as those in reality. To reiterate, the drawing is a schematic representation and may differ from the actual situation.

[0037] The flow path structure 14 is disposed on the holder 13. Flow paths through which ink flows are formed in the flow path structure 14. The flow path structure 14 includes a plurality of flow path substrates 19. The plurality of flow path substrates 19 are stacked in the thickness direction. For example, grooves and openings are formed in the flow path substrates 19. These grooves and openings form the flow paths. The flow path 116, flow paths 117A to 117D, flow paths 118A to 118D, and flow path 119 shown in FIG. 2 are formed in the flow path structure 14.

[0038] The flow path structure 14 is provided with an ink supply port 14a for introducing ink into the flow path structure 14 and an ink discharge port 14b for discharging ink from the flow path structure 14. In this embodiment, the ink supply port 14a and the ink discharge port 14b are provided so as to protrude in the Z2 direction from the flow path substrate 19 that is disposed at the uppermost position in the Z axis direction, that is, in the Z2 direction.

[0039] The relay substrate 15 covers the upper part of the central portion in the Y-axis direction of the flow path structure 14. A plurality of electrical wirings are provided on the relay substrate 15. The relay substrate 15 is electrically connected to the COF 60 of the head chip 20, which will be described in detail later, via a wiring member (not shown).

[0040] The connector 16 protrudes upward from the relay substrate 15. The connector 16 is electrically connected to electrical components outside the liquid jet head 10. The head chip 12 is electrically connected to the control unit 30 via the connector 16.

[0041] The upper cover 17 abuts the Z2-direction surface of the holder 13 at its Z1-direction end, and houses the flow path structure 14, relay board 15, and connector 16 between itself and the Z2-direction surface of the holder 13. The upper surface of the upper cover 17 on the Z2-direction side is provided with a wiring opening 17a for inserting an external wiring member into the connector 16, and openings 17b and 17c for connecting the ink supply port 14a and the ink discharge port 14b to a flow path member external to the liquid jet head 10, such as a tube. An ink supply flow path 114 and an ink discharge flow path 115 are formed inside this flow path member external to the liquid jet head 10.

[0042] 4, the outer shape of the liquid jet head 10 is indicated by a two-dot chain line. In a plan view seen in the Z1 direction, which is the jetting direction, the outer shape of the liquid jet head 10 has a central portion 81 and protruding portions 82 and 83. The protruding portion 82 protrudes in the Y2 direction from the central portion 81 when viewed in the Z-axis direction. The protruding portion 83 protrudes in the Y1 direction from the central portion 81 when viewed in the Z-axis direction.

[0043] Among the multiple liquid jet heads 10 lined up in the Y-axis direction, the protrusion 82 of the liquid jet head 10 positioned in the Y1 direction and the protrusion 83 of the liquid jet head 10 positioned in the Y2 direction are arranged so as to overlap when viewed in the X-axis direction.

[0044] Next, the arrangement of head chips 20A to 20D will be described with reference to Figure 4. Head chips 20A and 20C are aligned in the Y-axis direction. Head chips 20B and 20D are aligned in the Y-axis direction. When viewed in the Y-axis direction, head chips 20A and 20C are aligned so as to overlap. When viewed in the Y-axis direction, head chips 20B and 20D are aligned so as to overlap. When viewed in the Y-axis direction, head chips 20A and 20C do not overlap with head chips 20B and 20D. Head chips 20B and 20D are positioned in the X1 direction of head chips 20A and 20C.

[0045] When viewed in the X-axis direction, the Y2-direction end of head chip 20A and the Y1-direction end of head chip 20B are arranged to overlap. When viewed in the X-axis direction, a portion of the nozzle array NL of head chip 20A and a portion of the nozzle array NL of head chip 20B overlap. When viewed in the X-axis direction, the Y2-direction end of head chip 20B and the Y1-direction end of head chip 20C are arranged to overlap. When viewed in the X-axis direction, a portion of the nozzle array NL of head chip 20B and a portion of the nozzle array NL of head chip 20C overlap. When viewed in the X-axis direction, the Y2-direction end of head chip 20C and the Y1-direction end of head chip 20D are arranged to overlap. When viewed in the X-axis direction, a portion of the nozzle array NL of head chip 20C and a portion of the nozzle array NL of head chip 20D overlap. When viewed in the X-axis direction, the head chip 20D of one liquid jet head 10 is arranged so that an end portion in the Y2 direction of the head chip 20A of the other liquid jet head 10 overlaps with an end portion in the Y1 direction of the head chip 20A of the other liquid jet head 10. A portion of the nozzle row of the head chip 20D of one liquid jet head 10 overlaps with a portion of the nozzle row NL of the head chip 20A of the other liquid jet head 10 when viewed in the X-axis direction.

[0046] In head chip 20A, ink supply port 46A is arranged at the end in the Y2 direction, and ink discharge port 47A is arranged at the end in the Y1 direction. In head chip 20B, ink discharge port 47B is arranged at the end in the Y2 direction, and ink supply port 46B is arranged at the end in the Y1 direction. In head chip 20C, ink supply port 46C is arranged at the end in the Y2 direction, and ink discharge port 47C is arranged at the end in the Y1 direction. In head chip 20D, ink discharge port 47D is arranged at the end in the Y2 direction, and ink supply port 46D is arranged at the end in the Y1 direction.

[0047] In head chips 20A and 20B adjacent to each other in the X-axis direction, ink supply ports 46A and 46B are arranged close to each other. Ink supply ports 46A and 46B are arranged close to each other in the Y-axis direction. Ink supply port 46A is arranged closer to ink supply port 46B than ink discharge port 47B.

[0048] In head chips 20B and 20C adjacent to each other in the X-axis direction, ink discharge ports 47B and 47C are arranged close to each other. Ink discharge ports 47B and 47C are arranged close to each other in the Y-axis direction. Ink discharge port 47B is arranged closer to ink discharge port 47C than ink supply port 46C.

[0049] In head chips 20C and 20D adjacent to each other in the X-axis direction, ink supply ports 46C and 46D are arranged close to each other. Ink supply ports 46C and 46D are arranged close to each other in the Y-axis direction. Ink supply port 46C is arranged closer to ink supply port 46D than ink discharge port 47D.

[0050] Head chips 20B and 20C are arranged so as to overlap with central portion 81 when viewed in the Z-axis direction. The Y2-direction end of head chip 20A is arranged so as to overlap with central portion 81 when viewed in the Z-axis direction. The Y1-direction end of head chip 20A is arranged so as to overlap with protruding portion 83 when viewed in the Z-axis direction. The Y1-direction end of head chip 20D is arranged so as to overlap with central portion 81 when viewed in the Z-axis direction. The Y2-direction end of head chip 20D is arranged so as to overlap with protruding portion 82 when viewed in the Z-axis direction.

[0051] Next, the internal structure of the head chip 20 will be described with reference to Fig. 7. Fig. 7 is a cross-sectional view showing a cross section along the XZ plane of the head chip 20. The XZ plane is a plane along the X-axis direction and the Z-axis direction. The head chip 20 includes a common liquid chamber R, a relay flow path 42, a pressure chamber C, a communication flow path 44, a piezoelectric element 50, and a nozzle N. The head chip 20 also has a nozzle plate 21, a compliance substrate 23, a communication plate 24, a pressure chamber forming plate 25, a vibration plate 26, a sealing plate 27, and a case 28.

[0052] The thickness direction of the nozzle plate 21, compliance substrate 23, communication plate 24, pressure chamber forming plate 25, diaphragm 26, sealing plate 27, and case 28 is along the Z-axis direction. The nozzle plate 21, communication plate 24, pressure chamber forming plate 25, diaphragm 26, and sealing plate 27 are stacked in this order in the Z-axis direction. The compliance substrate 23 is located outside the nozzle plate 21 in the X-axis direction. The compliance substrate 23 is located in the Z1 direction of the communication plate 24.

[0053] The nozzle plate 21 extends in the Y-axis direction and has a predetermined length. A plurality of nozzles N are formed in the nozzle plate 21. The nozzles N are holes that penetrate the nozzle plate 21 in the thickness direction. The plurality of nozzles N form nozzle rows NL that are aligned in the Y-axis direction. The plurality of nozzle rows NL are spaced apart in the X-axis direction.

[0054] A part of the common liquid chamber R, a relay flow path 42, and a communication flow path 44 are formed in the communication plate 24. The Z1 direction portion of the common liquid chamber R is formed in the communication plate 24. The communication flow path 44 communicates with the nozzle N. The multiple communication flow paths 44 communicate with each of the multiple nozzles N. The nozzle plate 21 is arranged in the Z1 direction of the communication plate 24. The nozzles N are each arranged in the Z1 direction of the communication flow path 44. The communication plate 24 is made of a metal such as silicon or stainless steel.

[0055] The compliance substrate 23 is formed to cover the opening formed in the communicating plate 24. The space within the opening formed in the communicating plate 24 is included in the common liquid chamber R. The compliance substrate 23 is supported by the fixed plate 11 via a support plate 22. The support plate 22 is formed to surround the common liquid chamber R and the relay flow path 42 when viewed from the Z-axis direction. The support plate 22 is made of a metal such as stainless steel. A gap is formed between the common liquid chamber R and the fixed plate 11 in the Z-axis direction. The compliance substrate 23 is made of a flexible member such as a resin film or a thin metal plate, and reduces pressure fluctuations of the ink in the common liquid chamber R by deforming in the Z1 and Z2 directions so as to move toward and away from the fixed plate 11.

[0056] The pressure chamber forming plate 25 is located in the Z2 direction of the communication plate 24. A plurality of pressure chambers C are formed in the pressure chamber forming plate 25. The plurality of pressure chambers C are formed corresponding to the plurality of nozzles N, respectively. The pressure chambers C communicate with the relay flow paths 42 and the communication flow paths 44.

[0057] The vibration plate 26 is disposed in the Z2 direction of the pressure chamber forming plate 25. The vibration plate 26 constitutes the wall surface of the pressure chamber C in the Z2 direction. A plurality of piezoelectric elements 50 are disposed on the Z2 direction surface of the vibration plate 26. The plurality of piezoelectric elements 50 are provided corresponding to the plurality of pressure chambers C, respectively. The piezoelectric element 50 includes a plurality of electrodes and a piezoelectric layer disposed between the electrodes.

[0058] A sealing plate 27 is disposed in the Z2 direction of the vibration plate 26. The sealing plate 27 covers the plurality of piezoelectric elements 50. The sealing plate 27 reinforces the vibration plate 26 and also protects the plurality of piezoelectric elements 50.

[0059] A portion of the common liquid chamber R is formed in the case 28. The portion of the common liquid chamber R facing the Z2 direction is formed in the case 28, and the portion facing the Z1 direction is formed in the communication plate 24. An ink supply port 46 and an ink discharge port 47 are also formed in the case 58. As described above, the common liquid chamber R extends in the Y-axis direction and is commonly connected to a plurality of pressure chambers C. As shown in FIG. 4, the ink supply port 46 and the ink discharge port 47 are spaced apart in the Y-axis direction.

[0060] As shown in FIG. 7, ink passes through the ink supply port 46 and flows into the common liquid chamber R. The ink in the common liquid chamber R passes through the relay flow path 42 and flows into the pressure chamber C. The ink in the pressure chamber C passes through the communication flow path 44 and is ejected from the nozzle N.

[0061] The head chip 20 includes a COF 60. COF is an abbreviation for Chip on Film. The COF 60 includes a flexible wiring board 61 and a drive circuit 62. The flexible wiring board 61 is a flexible wiring board. The flexible wiring board 61 is, for example, an FPC. The flexible wiring board 61 may also be, for example, an FFC. FPC is an abbreviation for Flexible Printed Circuit. FFC is an abbreviation for Flexible Flat Cable.

[0062] The piezoelectric element 50 is electrically connected to a flexible wiring board 61 via a lead electrode (not shown). The drive circuit 62 is electrically connected to the flexible wiring board 61. The flexible wiring board 61 is electrically connected to the control unit 30 shown in FIG.

[0063] The piezoelectric element 50 is electrically connected to the control unit 30. The piezoelectric element 50 is controlled and driven by the control unit 30. The piezoelectric element 50 deforms the vibration plate 26 that forms the wall surface of the pressure chamber C, thereby changing the volume inside the pressure chamber 43. This causes the piezoelectric element 50 to eject ink inside the pressure chamber C from the nozzle N. Note that the liquid jet head 10 may be configured to include other driving elements, such as a heating element, instead of the piezoelectric element 50.

[0064] Each head chip 20 of this embodiment includes two nozzle rows NL. The two nozzle rows NL provided on the head chip 20 may eject the same type of liquid or different types of ink. Furthermore, the common liquid chambers RA to RD communicating with one of the two nozzle rows NL provided on each of the plurality of head chips 20 and the common liquid chambers RA to RD communicating with the other of the two nozzle rows NL provided on each of the plurality of head chips 20 may be independent flow paths. In other words, the liquid ejecting device 1 may include two sets of flow paths, each set of flow paths consisting of the flow path 116, the flow paths 117A to 117D, the flow paths 118A to 118D, the flow path 119, the liquid container 2, and the circulation mechanism 110, corresponding to each of the two nozzle rows NL. The number of nozzle rows NL provided on the head chip 20 and the number of flow path sets provided on the liquid ejecting device 1 are arbitrary.

[0065] Next, a change in the attitude of the liquid jet head 10 will be described with reference to FIG. 8. FIG. 8 is a schematic diagram showing the liquid jet head 10. In FIG. 8, the liquid jet head 10 in a first attitude P1 in which the ejection surface F1 is inclined with respect to the horizontal plane F0 is illustrated by a solid line, and the liquid jet head 10 in a second attitude P2 in which the ejection surface F1 is disposed along the horizontal plane F0 is illustrated by a two-dot chain line. The ejection surface F1 being inclined with respect to the horizontal plane F0 includes a case in which the ejection surface F1 intersects with the horizontal plane F0, and also a case in which the ejection surface F1 is perpendicular to the horizontal plane F0. The liquid jet head 10 can rotate about a rotation axis 151 extending in the X-axis direction. The ejection surface F1 is a surface 21a of the nozzle plate 21 on which the opening of the nozzle N is formed, as shown in FIG. 7. The surface 21a is a surface of the nozzle plate 21 facing the Z1 direction, which is the ejection direction in which the nozzle N ejects ink. In other words, the surface of the nozzle plate 21 opposite to the pressure chamber C in the Z-axis direction is the surface 21a.

[0066] 8, the attitude of the liquid jet head 10 is changeable to a plurality of attitudes including a first attitude P1 and a second attitude P2. The liquid jet device 1 has an attitude change mechanism 150 that changes the attitude of the liquid jet head 10. The attitude change mechanism 150 includes a bearing 152 that holds a rotation shaft 151 that extends in the X-axis direction, and a drive mechanism 153 that rotates the rotation shaft 151. The bearing 152 rotatably supports the rotation shaft 151. The drive mechanism 153 includes, for example, a motor. The rotation shaft 151 is connected to a carriage 5 that holds the liquid jet head 10.

[0067] It should be noted that the rotation shaft 151 may be located at the same position or at different positions in the first posture P1 and the second posture P2. The change in posture of the liquid jet head 10 from the first posture P1 to the second posture P2 may include linear movement of the liquid jet head 10. The liquid jet device 1 can linearly move the bearing 152 that holds the rotation shaft 151. For example, a rack and pinion can linearly move the rotation shaft 151 and the bearing 152. The liquid jet head 10 can also be linearly moved using other mechanisms such as a ball screw, a guide groove, an actuator, or a belt mechanism.

[0068] The liquid ejection device 1 performs a recording operation using the liquid ejection head 10 in the first position P1, and performs a circulation operation in the second position P2. A "recording operation" refers to ejecting ink from the nozzles N and depositing the ink on a medium to record characters, images, etc. A printing operation is an example of a recording operation. The liquid ejection device 1 can collect and circulate ink that was not ejected from the nozzles N during the recording operation.

[0069] When the liquid jet head 10 is in the first orientation P1, the ejection surface F1 intersects with the horizontal plane F0. In this embodiment, when the liquid jet head 10 is in the first orientation P1, the ejection surface F1 and the horizontal plane F0 intersect with each other at a substantially right angle. More specifically, in this embodiment, the angle θ1 formed between the ejection surface F1 and the horizontal plane F0 in the first orientation P1 is 90 degrees. Note that "substantially perpendicular" also includes orthogonal. Furthermore, when the angle θ1 formed between the ejection surface F1 and the horizontal plane F0 in the first orientation P1 is between 80 degrees and 100 degrees, the ejection surface F1 and the horizontal plane F0 may be considered to intersect with each other "substantially perpendicular." Note that the angle θ1 in the first orientation P1 may be an angle less than 80 degrees, such as 30 degrees, 45 degrees, or 60 degrees. With the liquid jet head 10 in this first orientation P1, ink is ejected from the nozzles N to perform a recording operation.

[0070] The angle θ2 between the ejection surface F1 and the horizontal plane F0 in the second attitude P2 of the liquid jet head 10 is smaller than the angle θ1. In this embodiment, the ejection surface F1 is substantially parallel to the horizontal plane F0 in the second attitude P2. More specifically, in this embodiment, the ejection surface F1 is parallel to the horizontal plane F0 in the second attitude P2. Note that "substantially parallel" includes "parallel." Furthermore, when the angle θ2 in the second attitude P2 is greater than or equal to -10 degrees and less than or equal to +10 degrees, the ejection surface F1 and the horizontal plane F0 may be considered "substantially parallel." The angle θ2 is, for example, a rotation angle around the X axis, where a clockwise rotation is considered positive and a counterclockwise rotation is considered negative. The angle θ2 may also be considered positive and negative in the counterclockwise rotation. In FIG. 8, the angle θ2 is not illustrated because the ejection surface F1 is disposed along the horizontal plane F0 in the second attitude P2. The angle θ2 is not limited to 0 degrees and may be a value greater than 0 degrees. The angles θ1 and θ2 may be the smaller of the angles formed between the horizontal plane F0 and the ejection surface F1. The difference between the angles θ1 and θ2 may be, for example, 5 degrees or more and 90 degrees or less.

[0071] The circulation operation performed in the second posture P2 includes, for example, a filling operation for filling ink into the liquid jet head 10. The filling operation for filling ink into the liquid jet head 10 includes an operation for filling ink into the plurality of head chips 20 and the flow paths 116, 117A to 117D, 118A to 118D, and 119. This filling operation is performed, for example, before using the liquid jet head 10 for the first time. For example, the filling operation is also performed after replacing the liquid jet head 10. The filling operation is also performed after periodic inspection of the liquid jet head 10 and before using the liquid jet head 10. The filling operation is also performed after maintenance such as ink replacement or cleaning of the flow paths. The filling operation may also include refilling the ink. These filling operations are sometimes referred to as "initial filling."

[0072] The circulation operation performed in the second posture P2 includes a cleaning operation for the liquid jet head 10. In the cleaning operation, ink is circulated. Other cleaning liquids may also be circulated in the cleaning operation. The cleaning operation may be performed periodically, for example. The cleaning operation may be performed when the duration of the recording operation exceeds a certain period of time, for example. The cleaning operation may be performed after the power of the liquid jet device 1 is turned on. The cleaning operation may be performed before or after the recording operation. The cleaning operation may also be performed when an abnormality is detected in the liquid jet head 10.

[0073] The circulation operation is not limited to the filling operation and the cleaning operation. The circulation operation may include other operations that circulate ink when a printing operation is not being performed. Other maintenance operations may be performed during the circulation operation.

[0074] In the circulation operation, as described above, the ink in the subtank 111 flows through the ink supply flow path 114 and is supplied to the liquid jet head 10. The ink discharged from the liquid jet head 10 flows through the ink discharge flow path 115 and is collected into the subtank 111.

[0075] In the circulation operation, ink introduced into the liquid jet head 10 flows through the flow paths 116 and the flow paths 117A to 117D and is supplied to the head chips 20A to 20D. The ink discharged from the head chips 20A to 20D flows through the flow paths 118A to 118D and the flow path 119 and is discharged into the ink discharge flow path 115.

[0076] In the circulation operation, ink introduced into head chips 20A to 20D passes through ink supply port 46 and is supplied into common liquid chamber R. The ink supplied into common liquid chamber R flows in the Y-axis direction within common liquid chamber R. The ink that has flowed within common liquid chamber R passes through ink outlet 47 and is discharged from head chips 20A to 20D. The ink that has been discharged from head chips 20A to 20D flows into flow paths 118A to 118D. The ink that has flowed through common liquid chamber R of head chips 20A to 20D is collected in subtank 111 as described above. In this manner, the ink is circulated.

[0077] The control unit 30 controls the circulation mechanism 110. The control unit 30 controls the pump 112 to perform the circulation operation. The control unit 30 controls the attitude change mechanism 150 to change the attitude of the liquid jet head 10. The control unit 30 controls the drive mechanism 153 to change the liquid jet head 10 to a first attitude P1 or a second attitude P2.

[0078] FIG. 9 is a side view showing the head chip 20 in the first orientation P1. In the first orientation P1, the position of the ink discharge port 47 relative to the ink supply port 46 is the same for the head chip 20A and the head chip 20C. Therefore, for convenience, FIG. 9 illustrates either the head chip 20A or 20C in the first orientation P1. In the head chip 20A in the first orientation P1, the ink discharge port 47A is positioned lower than the ink supply port 46A in the direction of gravity G1. In the head chip 20C in the first orientation P1, the ink discharge port 47C is positioned lower than the ink supply port 46C in the direction of gravity G1. In the head chips 20A and 20C in the first orientation P1, the ink flowing in the common liquid chambers RA and RC flows downward in the direction of gravity G1. In this embodiment, the ink in the common liquid chamber R flows along the Y axis. In the first orientation P1, the Y axis is parallel to the direction of gravity G1, so the ink flowing in the common liquid chambers RA and RC flows in the direction of gravity G1. The direction of gravity G1 is an example of a "first flow direction." The Y1 direction in the first attitude P1, which is the same direction as the direction of gravity G1, is also an example of a "first flow direction." Here, "downward in the direction of gravity G1" refers to facing downward with respect to the horizontal plane F0 when the direction of gravity G1 is defined as downward and the direction opposite to the direction of gravity G1 is defined as upward, and is not limited to the direction of gravity G1. Similarly, "upward in the direction of gravity G1" refers to facing upward with respect to the horizontal plane F0, and is not limited to the direction opposite to the direction of gravity G1.

[0079] Although not shown in FIG. 9, head chips 20B and 20D in first orientation P1 are upside down relative to head chips 20A and 20C. In head chip 20B in first orientation P1, ink supply port 46B is positioned lower than ink discharge port 47B in the direction of gravity G1. In head chip 20D in first orientation P1, ink supply port 46D is positioned lower than ink discharge port 47D in the direction of gravity G1. In head chips 20B and 20D in first orientation P1, ink flows in the common liquid chambers RB and RD upward in the direction of gravity G1. In this embodiment, ink flows in common liquid chamber R along the Y axis, and since the Y axis in first orientation P1 is parallel to the direction of gravity G1, ink flows in the common liquid chambers RB and RD in the direction opposite to the direction of gravity G1. The Y2 direction in first orientation P1, which is opposite to the direction of gravity G1, is an example of a "second flow direction."

[0080] 10 is a side view showing head chip 20 in second orientation P2. In second orientation P2, head chip 20A and head chip 20C have the same position of ink outlet 47 relative to ink supply port 46, so for convenience, FIG. 10 illustrates either head chip 20A or 20C in second orientation P2. In head chips 20A and 20C in second orientation P2, ink supply ports 46A and 46C and ink outlets 47A and 47C are arranged in the same position in the direction of gravity G1. In head chips 20A and 20C in second orientation P2, ink flowing in common liquid chambers RA and RC flows along horizontal plane F0 in the direction Y1 in second orientation P2.

[0081] Although not shown in FIG. 10, in the second orientation P2, the head chips 20B and 20D are oriented left and right inverted relative to the head chips 20A and 20C. For example, when viewed in the X1 direction, the Y1 direction is right and the Y2 direction is left. In the head chips 20B and 20D in the second orientation P2, the ink supply ports 46B and 46D and the ink discharge ports 47B and 47D are arranged in the same position in the direction of gravity G1. In the head chips 20B and 20D in the second orientation P2, the ink flowing in the common liquid chambers RB and RD flows in the Y2 direction in the second orientation P2 along the horizontal plane F0.

[0082] Such a liquid ejection device 1 includes a liquid ejection head 10 having an ejection surface F1 that ejects ink, a sub-tank 111 that stores ink to be supplied to the liquid ejection head 10, a circulation mechanism 110 that performs a circulation operation to circulate the ink between the liquid ejection head 10 and the sub-tank 111, and a control unit 30 that controls the circulation mechanism 110. The control unit 30 performs a recording operation with the liquid ejection head 10 at a first attitude P1 in which the ejection surface F1 intersects with a horizontal plane F0, and performs the circulation operation at a second attitude P2 in which the angle formed between the ejection surface F1 and the horizontal plane F0 is smaller than that of the first attitude P1.

[0083] In the liquid ejection device 1 of this embodiment, the circulation operation is performed in the second attitude P2, so the flow direction of the ink in the common liquid chamber R is in a direction that forms a smaller angle with respect to the horizontal plane F0 than in the first attitude P1. This makes it easier for air bubbles to be expelled from the common liquid chamber R compared to when the circulation operation is performed in the first attitude P1. Therefore, the risk of air bubbles remaining in the common liquid chamber R after the circulation operation is reduced, and the risk of air bubbles in the common liquid chamber R being drawn into the nozzles N or pressure chambers C during the subsequent recording operation, which could cause ejection defects, is suppressed. As a result, the reliability of the recording operation in the liquid ejection head 10 is improved.

[0084] For example, in the head chips 20A and 20C in the first posture P1 shown in FIG. 9, the Y1 direction of ink flow in the common liquid chambers RA and RC is the direction of gravity G1. The buoyancy acting on bubbles in the common liquid chambers RA and RC is opposite to the direction of gravity G1. Therefore, even if an ink circulation operation is performed for the head chips 20A and 20C in this first posture P1, bubbles in the common liquid chambers RA and RC are unlikely to be discharged from the ink outlets 47A and 47C. On the other hand, in the liquid ejection device 1, as shown in FIG. 10, the circulation operation is performed in the second posture P2. Therefore, the buoyancy acting on bubbles in the direction opposite to the Y1 direction of ink flow in the common liquid chambers RA and RC of the head chips 20A and 20C is smaller than in the first posture P1, and therefore bubbles in the common liquid chamber R are likely to be discharged from the ink outlets 47.

[0085] The circulation operation performed in the second attitude P2 includes a filling operation for filling the liquid jet head 10 with ink. With the liquid jet head 10 in the second attitude P2, the liquid jet head 10 can be filled with ink while circulating the ink. This allows the common liquid chamber R to be filled with ink, and also allows air bubbles in the common liquid chamber R to be discharged to the outside of the liquid jet head 10. This reduces the risk of air bubbles remaining in the common liquid chamber R. This prevents air bubbles from being drawn into the nozzles N or pressure chambers C during the subsequent recording operation.

[0086] The circulation operation performed in the second posture P2 includes a cleaning operation for the liquid jet head 10. In the liquid jet head 10 in the second posture P2, a cleaning operation can be performed while circulating ink. This cleans the ink flow paths in the liquid jet device 1 and also discharges air bubbles in the common liquid chamber R to the outside of the liquid jet head 10. This reduces the risk of air bubbles remaining in the common liquid chamber R. This prevents air bubbles in the common liquid chamber R from being drawn into the nozzles N or pressure chambers C during a subsequent recording operation. For example, by periodically performing a cleaning operation, air bubbles can be discharged from the common liquid chamber R. Furthermore, by performing a cleaning operation when an abnormality in the liquid jet head 10 is detected, the condition of the ink in the flow paths can be improved and air bubbles can be discharged from the common liquid chamber R. For example, the viscosity of the ink can be improved by performing a cleaning operation.

[0087] In the second attitude P2, the ejection surface F1 is approximately parallel to the horizontal plane F0. As a result, the flow direction of the ink in the common liquid chamber R is aligned with the horizontal plane F0, making it easier to expel air bubbles from the common liquid chamber R. In the liquid ejecting device 1, in the second attitude P2, the ejection surface F1 is approximately parallel to the horizontal plane F0, making it possible to make the air bubble expulsion performance uniform across the multiple head chips 20A to 20D.

[0088] The liquid jet head 10 has a head chip 20A and a head chip 20B. In this case, the head chip 20A is an example of a "first head chip", and the head chip 20B is an example of a "second head chip". The head chip 20A has a common liquid chamber RA that communicates with the multiple nozzles NA, an ink supply port 46A for introducing ink into the common liquid chamber RA, and an ink discharge port 47A for discharging ink from the common liquid chamber RA. The ink supply port 46A is an example of a "first supply port," and the ink discharge port 47A is an example of a "first discharge port." The head chip 20B has a common liquid chamber RB that communicates with the multiple nozzles NB, an ink supply port 46B for introducing ink into the common liquid chamber RB, and an ink discharge port 47B for discharging ink from the common liquid chamber RB. The ink supply port 46B is an example of a "second supply port," and the ink discharge port 47B is an example of a "second discharge port." The head chips 20A and 20B are arranged such that, in the first orientation P1, a first flow direction in which ink flows from the ink supply port 46A to the ink discharge port 47B and a second flow direction in which ink flows from the ink supply port 46B to the ink discharge port 47B are opposite to each other. As shown in FIG. 4, the first flow direction is the Y1 direction, and the second flow direction is the Y2 direction. The Y1 direction is opposite to the Y2 direction. The same is true for the head chips 20C and 20D. In the liquid ejection device 1, in the first orientation P1, the first and second flow directions intersect with the extension direction of the intersection line between the ejection surface F1 and the horizontal plane F0. In this embodiment, the extension direction of the intersection line between the ejection surface F1 and the horizontal plane F0 is the X-axis direction. As shown in FIG. 8, in the first orientation P1, the extension direction of the intersection line between the ejection surface F1 and the horizontal plane F0 is the X-axis direction.

[0089] The first flow direction and the second flow direction are directions along the ejection surface F1. As shown in FIG. 9, the ejection surface F1 is along the XY plane. The XY plane is a plane along the X-axis direction and the Y-axis direction. The first flow direction and the second flow direction are along the Y-axis direction. Also, as shown in FIG. 3, the direction in which the nozzle row NL extends is the Y-axis direction.

[0090] As shown in FIG. 4, in the liquid jet head 10, the head chip 20A and the head chip 20B are adjacent to each other, and the ink supply port 46A is disposed closer to the ink supply port 46B than to the ink discharge port 47B. In the liquid jet head 10, the head chip 20B and the head chip 20C are adjacent to each other, and the ink discharge port 47B is disposed closer to the ink discharge port 47C than the ink supply port 46C. In the liquid jet head 10, the head chip 20C and the head chip 20D are adjacent to each other, and the ink supply port 46C is disposed closer to the ink supply port 46D than the ink discharge port 47D. In liquid jet heads 10 adjacent to each other in the Y-axis direction, head chip 20D of one liquid jet head 10 is adjacent to head chip 20C of head chip 20A of the other liquid jet head 10, and ink discharge port 47D of one liquid jet head 10 is positioned closer to ink discharge port 47A than ink supply port 46A of the other liquid jet head 10.

[0091] According to the liquid ejection device 1 equipped with such a liquid ejection head 10, the ink supply ports 46A to 46D are arranged close to each other and the ink ejection ports 47A to 47D are arranged close to each other, thereby reducing the variation in the weight of ink ejected from the nozzles N of adjacent head chips 20. By doing so, the ink flows in opposite directions within the common liquid chamber R of adjacent head chips 20, but by performing the circulation operation in the second posture P2, air bubbles can be uniformly discharged from the common liquid chamber R of adjacent head chips 20.

[0092] Next, the first orientation P3 of the liquid jet head 10 according to Modification 1 will be described with reference to FIG. 11. FIG. 11 is a side view showing the first orientation P3 of the head chip 20 according to Modification 1. FIG. 11 illustrates head chips 20A and 20C in the first orientation P3. The head chip 20 in the first orientation P3 according to Modification 1 is tilted at an angle θ3 different from the head chip 20 in the first orientation P1 according to the first embodiment. The angle θ3 formed between the ejection surface F1 and the horizontal plane F0 in the first orientation P3 may be, for example, 45 degrees. The angle θ3 is larger than the angle θ2 and smaller than the angle θ1. In this way, the angle θ3 of the first orientation P3 may be an angle less than 90 degrees.

[0093] Next, the second orientation P4 of the liquid jet head 10 according to Modification 2 will be described with reference to FIG. 12. FIG. 12 is a side view showing the head chip 20 in the second orientation P4 according to Modification 2. FIG. 12 illustrates the head chips 20A and 20C in the second orientation P4. The head chip 20 in the second orientation P4 according to Modification 2 is inclined at an angle θ4 different from the head chip 20 in the second orientation P2 according to Embodiment 1. The angle θ4 between the ejection surface F1 and the horizontal plane F0 in the second orientation P4 may be, for example, 10 degrees. The angle θ4 may be greater than the angle θ2 or less than the angle θ3. In this way, the angle θ4 in the second orientation P4 may be greater than 0 degrees. In the liquid jet device 1 according to the modification, a circulation operation can be performed with the head chip 20 in the second orientation P4. When the angle θ4 is smaller than the angles θ1 and θ3, air bubbles are more easily discharged from the common liquid chamber R when the head chip 20 is in the second attitude P4 than when it is in the first attitudes P1 and P3.

[0094] Next, a liquid jet head 10B according to a second embodiment will be described. FIG. 13 is a bottom view showing the liquid jet head 10B according to the second embodiment. Note that the liquid jet head 10B shown in FIG. 13 is a bottom view showing the liquid jet head 10B in a state in which it is in the first posture P1. FIG. 13 shows the V-axis direction and the W-axis direction. The V-axis direction and the W-axis direction intersect with each other when viewed from the Z-axis direction. The V-axis direction is inclined at a predetermined angle with respect to the Y-axis direction. The V-axis direction includes the V1 direction and the V2 direction, which are opposite directions. The W-axis direction is inclined at a predetermined angle α with respect to the X-axis direction. The W-axis direction includes the W1 direction and the W2 direction.

[0095] The liquid ejecting apparatus 1B according to the second embodiment includes a plurality of liquid ejecting heads 10B. The liquid ejecting apparatus 1 according to the second embodiment differs from the liquid ejecting apparatus 1 according to the first embodiment in that the liquid ejecting apparatus 1B includes a liquid ejecting head 10B instead of the liquid ejecting head 10. Note that in the description of the second embodiment, the same description as in the first embodiment may be omitted.

[0096] The liquid jet head 10B includes a plurality of head chips 20E, 20F. The head chips 20E, 20F extend in the V-axis direction. The head chips 20E, 20F each have a plurality of nozzles N. The plurality of nozzles N form a nozzle row NL aligned in the V-axis direction. Although not shown, the common liquid chambers RE, RF of the head chips 20E, 20F extend in the V-axis direction and are commonly connected to the plurality of nozzles N. In other words, the ink in the common liquid chambers RE, RF flows along the V-axis.

[0097] Head chips 20E and 20F are arranged alternately in the X-axis direction. Head chip 20E has ink supply port 46E and ink discharge port 47E that communicate with common liquid chamber RE. Head chip 20F has ink supply port 46F and ink discharge port 47F that communicate with common liquid chamber RF.

[0098] The ink supply port 46E is located further in the Y2 direction than the ink discharge port 47E. The ink discharge port 47F is located further in the Y2 direction than the ink supply port 46F.

[0099] In the first orientation P1 of the liquid jet head 10B of this embodiment, as in the first embodiment, the Y1 direction is aligned with the direction of gravity G1. In the first orientation P1 of the liquid jet head 10B, ink in the common liquid chamber RE of the head chip 20E flows in the direction of gravity G1 when viewed in the X-axis direction, in other words, flows downward in the direction of gravity G1. Specifically, in the first orientation P1 of the liquid jet head 10B, ink in the common liquid chamber RE of the head chip 20E flows along the V1 direction in the first orientation P1. In the first orientation P1 of the liquid jet head 10B, ink in the common liquid chamber RF of the head chip 20F flows in the direction opposite to the direction of gravity G1 when viewed in the X-axis direction, in other words, flows upward in the direction of gravity G1. Specifically, in the first orientation P1 of the liquid jet head 10B, ink in the common liquid chamber RF of the head chip 20F flows along the V2 direction in the first orientation P1.

[0100] In the second attitude P2 of the liquid jet head 10B of this embodiment, similar to the first embodiment, the Y-axis direction is arranged to be along the horizontal plane F0. The horizontal plane F0 is shown in FIG. 10. In the second attitude P2 of the liquid jet head 10B, the ejection surface F2 is aligned with the horizontal plane F0. The flow of ink in the common liquid chambers RE, RF in the head chips 20E, 20F is aligned with the horizontal plane F0.

[0101] The liquid ejecting apparatus 1B including such a liquid ejecting head 10B also performs a recording operation in the first attitude P1 and a circulating operation in the second attitude P2. The liquid ejecting apparatus 1B according to the second embodiment also achieves the same effects as the liquid ejecting apparatus 1 according to the first embodiment.

[0102] Next, a liquid ejecting apparatus 1C according to embodiment 3 will be described with reference to Fig. 14. Fig. 14 is a schematic diagram showing an ink flow path in liquid ejecting apparatus 1C according to embodiment 3. Liquid ejecting apparatus 1C of embodiment 3 differs from embodiment 1 shown in Fig. 1 in that it includes a blocking member 121, a negative pressure generating unit 122, and a tank 123.

[0103] The liquid ejection device 1C includes a closing member 121. The closing member 121 is, for example, plate-shaped and closes the multiple nozzles N formed on the ejection surface F1. The closing member 121 can come into contact with the ejection surface F1. The closing member 121 may be made of, for example, rubber or other materials. The closing member 121 may have a structure having multiple protrusions that can be inserted into the multiple nozzles N. For example, the liquid ejection head 10 moves, thereby allowing the closing member 121 to come into contact with the ejection surface F1. The closing member 121 may be moved to come into contact with the ejection surface F1.

[0104] The liquid ejecting device 1C includes a negative pressure generating unit 122. The negative pressure generating unit 122 of this embodiment is connected to the subtank 111 and can create a negative pressure inside the subtank 111. The negative pressure generating unit 122 may have a configuration similar to that of the pressure adjusting unit 111b of the first embodiment. The negative pressure generating unit 122 includes, for example, a compressor. The negative pressure generating unit 122 may be directly connected to the subtank 111 or may be connected to the subtank 111 via another flow path. The negative pressure generating unit 122 may also be provided in the ink discharge flow path 115 rather than in the subtank 111. The negative pressure generating unit 122 is not limited to a compressor and may be another suction pump such as a tube pump, a syringe pump, or a diaphragm pump.

[0105] The liquid ejection device 1C includes a tank 123. The tank 123 is connected, for example, between the pump 112 and the temperature adjustment unit 113. The tank 123 temporarily stores ink. The ink in the tank 123 is supplied to the liquid ejection head 10 via an ink supply channel 114. The tank 123 may be connected between the temperature adjustment unit 113 and the liquid ejection head 10.

[0106] The liquid ejection device 1C has a check valve 138. The check valve 138 is provided in the ink supply flow path 114 between the sub-tank 111 and the pump 112. The check valve 138 can prevent ink from flowing back from the pump 112 to the sub-tank 111. This makes it possible to effectively create a negative pressure inside the liquid ejection head 10 via the sub-tank 111 by driving the negative pressure generating unit 122.

[0107] The liquid ejecting device 1C does not necessarily have to include the check valve 138. The liquid ejecting device 1C may be configured to include an on-off valve instead of the check valve 138. When the negative pressure generating unit 122 is driven, the on-off valve is closed to prevent ink from flowing back into the subtank 111. Furthermore, the pump 112 may be capable of preventing ink from flowing back into the subtank 111. For example, if the pump 112 is a tube pump, it can prevent ink from flowing back into the subtank 111.

[0108] The liquid ejecting device 1C according to the third embodiment includes a closing member 121 that can come into contact with the ejection surface F1. The liquid ejecting head 10 includes a filter 136A that is disposed upstream of the ink supply port 46A, and a filter 136B that is disposed upstream of the ink supply port 46B. The filter 136A is an example of a "first filter," and the filter 136B is an example of a "second filter." The circulation mechanism 110B has a negative pressure generating unit 122 disposed downstream of the ink outlets 47A and 47B. The circulation operation in the second attitude P2 includes an operation of generating negative pressure in the common liquid chambers RA and RB through the ink outlets 47A and 47B by driving the negative pressure generating unit 122 while the plurality of nozzles N are blocked by the blocking member 121.

[0109] According to this liquid ejecting device 1C, the filters 136A-136D are provided for the head chips 20A-20D, which provide resistance to the flow of ink, and the multiple nozzles N are blocked by the blocking member 121, so that the pressure inside the common liquid chambers RA-RD can be efficiently reduced by driving the negative pressure generating unit 122. This allows the air bubbles inside the common liquid chambers RA-RD to become larger, and the bubbles with increased volume are more likely to be pulled toward the ink outlet 47. Larger bubbles are more likely to be pulled by the negative pressure generating unit 122 than smaller bubbles. Therefore, the air bubbles are more likely to be discharged from the common liquid chambers RA-RD.

[0110] During the circulation operation in the second posture P2, the control unit 30 does not apply pressure from the upstream of the head chips 20A to 20D. The upstream of the head chips 20A to 20D includes the upstream of the liquid jet head 10. The upstream of the liquid jet head 10 includes the ink supply flow path 114 between the sub-tank 111 and the liquid jet head 10. During the circulation operation in the second posture P2, the control unit 30 does not apply pressure by the pump 112 provided upstream of the head chips 20A to 20D. This reduces the inflow of ink from the upstream of the head chips 20A to 20D compared to when the circulation operation is performed while pressurizing with the pump 112, making it easier to reduce the pressure inside the common liquid chambers RA to RD. Therefore, by increasing the volume of air bubbles in the common liquid chambers RA to RD, the air bubbles are more likely to be sucked toward the negative pressure generating unit 122 and are more likely to be discharged from the common liquid chambers RA to RD.

[0111] In the liquid ejection device 1C, no filters are present between the ink discharge ports 47A-47D and the negative pressure generator 122. In the liquid ejection head 10, filters 136A-136D are disposed upstream of the head chips 20A-20D, and no filters are present downstream of the head chips 20A-20D. The flow paths 118A-118D, the flow path 119, and the ink discharge flow path 115 are not provided with a filter 136. If filters 136A-136D were present between the ink discharge ports 47A-47D and the negative pressure generator 122, it would be difficult to reduce the pressure inside the common liquid chambers RA-RD. However, in the liquid ejection device 1C, since no filters 136A-136D are present in the flow paths between these paths, the negative pressure generator 122 can easily reduce the pressure inside the common liquid chambers RA-RD. As a result, in the liquid ejection device 1C, air bubbles can be easily removed from the common liquid chambers RA-RD.

[0112] Next, a liquid ejecting device 1G according to a fourth embodiment will be described with reference to FIGS. 15 and 16. FIG. 15 is a side view showing a first attitude P1 of a head chip 20G according to the fourth embodiment. FIG. 16 is a side view showing a second attitude P2 of a head chip 20G according to the fourth embodiment. The liquid ejecting device 1G includes a liquid ejecting head 10G having a plurality of head chips 20G. The liquid ejecting device 1G differs from the liquid ejecting device 1 according to the first embodiment in that the liquid ejecting device 1G includes a liquid ejecting head 10G having a head chip 20G instead of the liquid ejecting head 10 having head chips 20A to 20D. Note that in the description of the liquid ejecting device 1G according to the fourth embodiment, descriptions similar to those of the first embodiment may be omitted.

[0113] The liquid jet head 10G may be configured to include one head chip 20G or multiple head chips 20G. The head chip 20G includes a common liquid chamber RG that is in common communication with multiple nozzles N. The configuration of the head chip 20G is substantially the same as that of the head chip 20 shown in FIG. 7, except for the supply port 46G, the discharge ports 47G and 47H, and the common liquid chamber RG.

[0114] As shown in Figures 15 and 16, the head chip 20G has a supply port 46G, a discharge port 47G, and a discharge port 47H. These supply port 46G, discharge port 47G, and discharge port 47H are connected to a common liquid chamber RG. An ink supply flow path is connected to the supply port 46G. An ink discharge flow path is connected to the discharge ports 47G and 47H. Ink in the ink supply flow path is supplied from the supply port 46G into the common liquid chamber RG. Ink in the common liquid chamber RG is discharged from the discharge ports 47G and 47H and flows into the ink discharge flow path.

[0115] Supply port 46G is located between discharge port 47G and discharge port 47H in the Y-axis direction. Discharge port 47G is located on the Y2 side of supply port 46G. Discharge port 47H is located on the Y1 side of supply port 46G.

[0116] A portion of the ink flowing in from the supply port 46G flows in the common liquid chamber RG in the Y2 direction and is discharged from the discharge port 47G. A portion of the ink flowing in from the supply port 46G flows in the common liquid chamber RG in the Y1 direction and is discharged from the discharge port 47H. In the liquid ejecting device 1G, a printing operation is performed in the first attitude P1, and a circulation operation is performed in the second attitude P2. In the liquid ejecting device 1G, by performing a circulation operation in the second attitude P2, air bubbles in the common liquid chamber RG are discharged from the discharge ports 47G and 47H.

[0117] The liquid ejection device 1G includes a liquid ejection head 10G. The liquid ejection head 10G has a common liquid chamber RG that communicates with a plurality of nozzles N, a supply port 46G for introducing ink into the common liquid chamber RG, and outlets 47G and 47H for discharging ink from the common liquid chamber RG. In the first orientation P1, the supply port 46G is disposed between the outlets 47G and 47H in the direction of gravity G1. In this manner, the liquid ejection device 1G may be configured to include the liquid ejection head 10G. In the liquid ejection device 1G, a circulation operation can be performed in the second orientation P2, so that the flow of ink in the common liquid chamber RG is along the horizontal plane F0. This makes it easier to discharge air bubbles from the common liquid chamber RG.

[0118] When the ink is circulated in the first orientation P1 shown in FIG. 15, ink flowing in from the supply port 46G flows into the common liquid chamber RG at the center in the Y-axis direction and is divided. A portion of the ink flowing in from the supply port 46G flows in the common liquid chamber RG in the Y2 direction, i.e., the direction opposite to the direction of gravity G1, while the remaining portion of the ink flowing in from the supply port 46G flows in the common liquid chamber RG in the Y1 direction, i.e., the direction of gravity G1. For example, air bubbles present in the lower portion of the common liquid chamber RG are pushed in the Y1 direction by the ink flow in the Y1 direction, but buoyancy acts on the air bubbles in the Y2 direction. Therefore, air bubbles in the common liquid chamber RG are subject to buoyancy in the direction opposite to the ink flow in the Y1 direction, making them difficult to expel from the common liquid chamber RG. For example, air bubbles may accumulate in the center of the common liquid chamber RG where the ink flowing in from the supply port 46G meets. In the liquid ejection device 1G according to the fourth embodiment, the circulation operation is performed in the second attitude P2 shown in FIG. 16, so that the air bubbles in the common liquid chamber RG flow in a direction along the horizontal plane F0 and are easily discharged from the discharge ports 47G, 47H.

[0119] It should be noted that the above-described embodiment merely shows a typical form of the present invention, and the present invention is not limited to the above-described embodiment, and various modifications and additions are possible within the scope that does not deviate from the gist of the present invention.

[0120] In the above embodiment, the flow direction of ink in the common liquid chamber R in the second attitude P2 is described as being along the horizontal plane F0, but the flow direction of ink in the common liquid chamber R is not limited to this. The flow of ink in the common liquid chamber R in the second attitude P2 does not have to be along the horizontal plane F0. The flow of ink in the common liquid chamber R in the second attitude P2 may include a flow in a direction that is not along the horizontal plane F0.

[0121] In the above embodiment, the case where ink supply port 46B is located near ink supply port 46A is illustrated, but the location of head chips 20A, 20B is not limited to this. Ink discharge port 47B may be located near ink supply port 46A, or ink discharge port 47A may be located near ink supply port 46B.

[0122] In the liquid ejection device 1C shown in Figure 14, a case is described in which multiple blocking members 121 are arranged corresponding to each head chip 20, but the blocking members 121 may also be arranged so as to abut against the ejection surfaces F1 of multiple head chips 20.

[0123] In the above embodiment, the circulation operation may be performed during the printing operation in the first attitude P1. In other words, both the circulation operation in the second attitude P2 for discharging air bubbles from the common liquid chamber R and the circulation operation performed during the printing operation in the first attitude P1 may be performed.

[0124] In the above-described embodiment, a serial-type liquid ejection device 1 is exemplified, in which a carriage carrying a liquid ejection head 10 is moved back and forth in the width direction of the medium PA, but the present invention may also be applied to a line-type liquid ejection device equipped with multiple liquid ejection heads 10.

[0125] The liquid ejection device 1 illustrated in the above-described embodiment can be employed in various devices such as facsimile machines and copiers, as well as devices dedicated to printing. However, the use of the liquid ejection device of the present invention is not limited to printing. For example, a liquid ejection device that ejects a solution of a coloring material is used as a manufacturing device for forming color filters for display devices such as liquid crystal display panels. Furthermore, a liquid ejection device that ejects a solution of a conductive material is used as a manufacturing device for forming wiring and electrodes on a wiring board. Furthermore, a liquid ejection device that ejects a solution of an organic substance related to a living organism is used as a manufacturing device for manufacturing biochips, for example. [Explanation of symbols]

[0126] 1, 1B, 1C, 1G...liquid ejection device, 10, 10B...liquid ejection head, 20, 20A to 20G...head chip, 21...nozzle plate, 30...control unit, 110...circulation mechanism, 46, 46A to 46F...ink supply port, 46G...supply port, 47, 47A to 47F...ink discharge port, 47G, 47H...discharge port, 110, 110B...circulation mechanism, 111...subtank, 136A to 136D...filter, F0...horizontal surface, F1...ejection surface, G1...direction of gravity, N...nozzle, NL...nozzle row, P1, P3...first position, P2, P4...second position, R, RA to RG...common liquid chamber, X...X-axis direction, Y...Y-axis direction, Y1...Y1 direction, Y2...Y2 direction, Z...Z-axis direction.

Claims

1. a liquid ejection head having an ejection surface that ejects liquid; a tank that stores a liquid to be supplied to the liquid jet head; a circulation mechanism for circulating the liquid between the liquid ejection head and the tank; Structure and a control unit that controls the circulation mechanism; Equipped with The control unit rotates the liquid jet head around a rotation axis perpendicular to the direction of gravity. The ejection surface is in a first position where it intersects with the horizontal plane, or the ejection surface and the horizontal plane form a first position. The angle can be changed to a second attitude having a smaller angle than the first attitude, The liquid jet head includes: a plurality of first individual flow paths connected to the plurality of first nozzles, respectively; a first common liquid chamber connected to the plurality of first individual flow paths; a first supply port for introducing liquid into the first common liquid chamber; a first discharge port for discharging liquid from the first common liquid chamber; Pu and, a plurality of second individual flow paths connected to the plurality of second nozzles, respectively; a second common liquid chamber connected to the plurality of second individual flow paths; a second supply port for introducing liquid into the second common liquid chamber; a second discharge port for discharging the liquid from the second common liquid chamber; and the first head chip and the second head chip are adjacent to each other, In the first position, the first discharge port is lower than the first supply port in the direction of gravity. and is located toward the first supply port and the first discharge port as viewed in a direction along the rotation axis. a first flow direction in which liquid flows and a second flow direction in which liquid flows from the second supply port to the second discharge port; The direction of the light is opposite to that of the light source. The distance between the first supply port and the first discharge port in the gravity direction in the second attitude is a distance between the first supply port and the first discharge port in the direction of gravity in the first attitude; and the distance in the direction of gravity between the second supply port and the second discharge port in the second attitude. The distance is greater than the distance in the direction of gravity between the second supply port and the second discharge port in the first posture. It is smaller than The control unit executes a recording operation by the liquid ejection head in the first attitude, and The liquid ejecting apparatus is characterized in that the circulation operation is performed in a posture.

2. The circulation operation includes an operation of supplying liquid from the tank to the liquid jet head and an operation of supplying liquid to the head. The liquid ejection device according to claim 1 , further comprising: an operation of recovering the liquid from the head into the tank.

3. The circulation operation performed in the second posture is a filling operation of filling the liquid into the liquid jet head. The liquid ejection device according to claim 1 or 2, further comprising an operation.

4. The circulation operation performed in the second posture is a cleaning operation for the liquid ejection head. The liquid ejection device according to claim 1 , further comprising:

5. In the first attitude, the ejection surface and the horizontal plane intersect substantially perpendicularly.

10. The liquid ejection apparatus according to claim 1 ,

6. In the second attitude, the ejection surface is substantially parallel to a horizontal plane. The liquid ejection apparatus according to any one of claims 1 to 14,

7. The first flow direction and the second flow direction are directions along the ejection surface. The liquid ejection apparatus according to any one of claims 1 to 14,

8. The first discharge port is disposed closer to the second discharge port than the second supply port. Or, The first supply port is disposed closer to the second supply port than the second discharge port. The liquid ejection device according to any one of claims 1 to 7.

9. a blocking member that can contact the ejection surface, the liquid jet head includes: a first filter disposed upstream of the first supply port; a second filter disposed upstream of the second supply port, the circulation mechanism has a negative pressure generating unit disposed downstream of the first and second outlets, The circulation operation in the second position is performed by closing the first nozzles and the second nozzles with the closing member. By driving the negative pressure generating unit in a state where the second nozzle is closed, the first and second 9. The method according to claim 1, further comprising the step of applying a negative pressure to the first and second common liquid chambers through a discharge port. The liquid ejection apparatus according to any one of claims 1 to 14,

10. The control unit controls the first and second head chips in the circulation operation in the second posture. The liquid ejection device according to claim 9 , wherein pressure is not applied from upstream of the pump.

11. There is no filter between the first and second outlets and the negative pressure generating unit. The liquid ejection apparatus according to claim 9 or 10.

12. a liquid ejection head having an ejection surface that ejects liquid; a tank that stores a liquid to be supplied to the liquid jet head; a circulation mechanism for circulating the liquid between the liquid ejection head and the tank; Structure and a control unit that controls the circulation mechanism; a blocking member that can come into contact with the ejection surface; Equipped with The control unit controls the liquid ejection head in a first attitude in which the ejection surface intersects with a horizontal plane. a recording operation is performed by the ejection surface, and an angle formed by the ejection surface and a horizontal plane is smaller than that of the first attitude; The circulation operation is performed in two positions, The liquid jet head includes: a first common liquid chamber communicating with the plurality of first nozzles; a first supply port for introducing liquid into the first common liquid chamber; a first discharge port for discharging liquid from the first common liquid chamber; Top and a first filter disposed upstream of the first supply port, the circulation mechanism has a negative pressure generating unit disposed downstream of the first discharge port, The circulation operation in the second position is performed in a state where the plurality of first nozzles are blocked by the blocking member. By driving the negative pressure generating unit in this state, a negative pressure is generated in the first common liquid chamber through the first outlet. Including pressing actions, The control unit is configured to control the upstream side of the first head chip during the circulation operation in the second posture. A liquid ejection device characterized in that pressure is not applied from the outside.

13. a liquid ejection head having an ejection surface that ejects liquid; a tank that stores a liquid to be supplied to the liquid jet head; a circulation mechanism for circulating the liquid between the liquid ejection head and the tank; Structure and a control unit that controls the circulation mechanism; Equipped with The liquid jet head includes a plurality of individual flow paths connected to the plurality of nozzles, and a common liquid chamber connected to the individual flow paths; a supply port for introducing liquid into the common liquid chamber; a first outlet and a second outlet for discharging the liquid from the common liquid chamber; In a first attitude in which the ejection surface intersects with a horizontal plane, the supply port is and is disposed between the first exhaust port and the second exhaust port, The control unit executes a recording operation by the liquid ejection head in the first attitude, The circulating motion is performed in a second posture in which the angle formed between the surface and the horizontal plane is smaller than that in the first posture. , liquid injection device.

14. A liquid is supplied from a tank that stores the liquid to a liquid ejection head, and the liquid is ejected from the liquid ejection head. performing a recording operation by ejecting a liquid from the surface; performing a circulation operation for circulating liquid between the liquid ejection head and the tank; 、 The liquid ejection head is rotated around a rotation axis perpendicular to the direction of gravity, thereby a first attitude in which the surface intersects with a horizontal plane, or an angle formed by the ejection surface and the horizontal plane is and changing the orientation of the target object to a second orientation that is smaller than the orientation of the target object, The liquid jet head includes: a plurality of first individual flow paths connected to the plurality of first nozzles, respectively; a first common liquid chamber connected to the plurality of first individual flow paths; a first supply port for introducing liquid into the first common liquid chamber; a first discharge port for discharging liquid from the first common liquid chamber; Pu and, a plurality of second individual flow paths connected to the plurality of second nozzles, respectively; a second common liquid chamber connected to the plurality of second individual flow paths; a second supply port for introducing liquid into the second common liquid chamber; a second discharge port for discharging the liquid from the second common liquid chamber; and the first head chip and the second head chip are adjacent to each other, In the first position, the first discharge port is lower than the first supply port in the direction of gravity. and is located toward the first supply port and the first discharge port as viewed in a direction along the rotation axis. a first flow direction in which liquid flows and a second flow direction in which liquid flows from the second supply port to the second discharge port; The direction of the light is opposite to that of the light source. The distance between the first supply port and the first discharge port in the gravity direction in the second attitude is a distance between the first supply port and the first discharge port in the direction of gravity in the first attitude; and the distance in the direction of gravity between the second supply port and the second discharge port in the second attitude. The distance is greater than the distance in the direction of gravity between the second supply port and the second discharge port in the first posture. It is smaller than The execution of the recording operation is performed by the liquid ejection head in the first attitude. Run, performing the circulating motion in the second posture; A liquid injection method.

Images