JP7366586B2 - Liquid ejection head and liquid ejection device - Google Patents

Description

Embodiments of the present invention relate to a liquid ejection head and a liquid ejection device.

As a liquid ejection head used in various liquid ejection devices, there is a known technology that has a plurality of pressure chambers, drives a drive element to change the volume of the pressure chamber, and ejects the liquid in the pressure chamber from a nozzle. . As a specific example, the liquid ejection head includes a liquid ejection section that has a common chamber on the primary side and the secondary side of a plurality of pressure chambers, respectively. The liquid flowing through the liquid discharge part flows into a common chamber on the primary side of the plurality of pressure chambers, passes through the plurality of pressure chambers, passes through the common chamber on the secondary side of the plurality of pressure chambers, and is discharged. is discharged to the secondary side of the unit. Then, as the volume of the pressure chamber increases or decreases, the liquid within the pressure chamber is discharged as droplets from the nozzle.

The temperature of the liquid in such a liquid discharge section becomes high at a position farthest from a position where the liquid is supplied to a common chamber on the primary side of the plurality of pressure chambers, and a temperature difference occurs in the liquid within the liquid discharge section. Therefore, it is required to equalize the temperature of the liquid within the liquid discharge section.

Japanese Patent Application Publication No. 2015-150740

An object of the present invention is to provide a liquid ejection head and a liquid ejection device that can uniformize the temperature of liquid in a liquid ejection section.

A liquid ejection head according to one embodiment includes a liquid ejection section, an inflow pipe section, an outflow pipe section, and a cooling device. The liquid discharge section includes a first common chamber, an actuator that configures a plurality of pressure chambers connected to the first common chamber, and a second common chamber connected to the plurality of pressure chambers. The inflow pipe section supplies liquid to the first common chamber. The outflow pipe section discharges the liquid from the second common chamber. The cooling device includes a cooling plate and a cooling channel through which a cooling liquid passes. The direction along the longitudinal direction of the actuator is the X direction, the direction in which the first common chamber and the second common chamber face each other via the pressure chamber is the Y direction, and the direction perpendicular to the X direction and the Y direction is the direction. When the Z direction is assumed, the plurality of pressure chambers are provided in line along the X direction at one end of the actuator in the Z direction. The cooling channel includes a first cooling channel provided in the cooling plate and a second cooling channel provided in the actuator. The second cooling flow path is provided at a position where the pressure chamber side furthest from the inflow pipe section side in the X direction is closer to the pressure chamber in the Z direction than the inflow pipe section side in the X direction. It will be done.

FIG. 1 is a perspective view schematically showing the configuration of a liquid ejection head according to a first embodiment. FIG. 3 is a perspective view showing the configuration of a head device used in the liquid ejection head. FIG. 3 is a side view showing the configuration of the head device. FIG. 2 is a perspective view showing the configuration of main parts of the head device. FIG. 3 is a side view showing the configuration of main parts of the head device. FIG. 3 is an exploded perspective view showing the configuration of a liquid ejection section used in the head device. FIG. 3 is a cross-sectional view showing the configuration of the liquid discharge section. FIG. 3 is a perspective view showing the structure of an actuator and a cover plate of the liquid discharge section. FIG. 3 is a perspective view showing the configuration of the actuator. FIG. 2 is an explanatory diagram schematically showing the configuration of a liquid ejection device in which the same liquid ejection head is used. FIG. 3 is an explanatory diagram showing an example of the temperature distribution of liquid in the liquid ejection section of the head device. FIG. 7 is a side view schematically showing the configuration of a head device of a liquid ejection head according to another embodiment.

The liquid ejection head 1 according to the first embodiment will be described below with reference to FIGS. 1 to 11.

FIG. 1 is a perspective view schematically showing the configuration of a liquid ejection head 1 according to the first embodiment. 2 to 5 show the entire configuration and essential parts of the head device 5, with FIGS. 2 and 4 being perspective views, and FIGS. 3 and 5 being side views. 6 and 7 are an exploded perspective view and a cross-sectional view showing the configuration of the liquid ejection section 10 of the head device 5. FIG. FIG. 8 is a perspective view showing the structure of the actuator 21 and cover plate 22 of the liquid discharge section 10, and FIG. 9 is a perspective view showing the structure of the actuator 21. FIG. 10 is an explanatory diagram schematically showing the configuration of a liquid ejection apparatus 100 in which the liquid ejection head 1 is used. FIG. 11 is an explanatory diagram showing an example of the temperature distribution flowing inside the liquid discharge section 10.

In addition, in the figure, X, Y, and Z indicate three directions that are orthogonal to each other. The following description will be made assuming that the direction along the opposing direction of the nozzle plate 24 is the Z direction. Further, in each figure, for convenience of explanation, the configuration is shown enlarged, reduced, or omitted as appropriate.

As shown in FIG. 1, the liquid ejection head 1 includes, for example, an outer case 4 and a plurality of head devices 5 housed in the outer case 4.

For example, the liquid ejection head 1 is provided in a liquid ejection apparatus 100 such as an inkjet recording apparatus shown in FIG. The liquid ejection head 1 is a circulation type head that is connected to a circulation device 2 that includes a supply tank 132 as a liquid storage section provided in the liquid ejection apparatus 100 and circulates ink between the supply tank 132 and the supply tank 132 .

As shown in FIGS. 2 to 6, the head device 5 includes a liquid discharge section 10, a base plate 11, a circuit board 12, and a cooling device 13. For example, in the head device 5, the liquid discharge section 10, the base plate 11, the circuit board 12, and the cooling device 13 are assembled together. The head device 5 is, for example, a share mode share wall type head. For example, the plurality of head devices 5 are arranged in a stacked manner with adjacent head devices 5. The head device 5 is configured as a liquid ejection head 1, and when installed in the liquid ejection apparatus 100, it is arranged such that, for example, a nozzle 24a, which will be described later, of the liquid ejection section 10 faces downward in the direction of gravity.

As shown in FIGS. 2 to 6, the liquid discharge unit 10 includes an actuator 21, a pair of cover plates 22 that cover both main surfaces of the actuator 21, and a pair of flow streams that cover both main surfaces of the actuator 21 and the cover plate 22. It includes a passage cover 23 and a nozzle plate 24. Note that in FIGS. 2 and 3, the nozzle plate 24 is omitted.

The actuator 21 is formed into a plate shape that is long in one direction. The actuator 21 is configured in a plate shape using a laminated piezoelectric body in which a pair of piezoelectric members are laminated, for example. For example, PZT (lead zirconate titanate) is used as the piezoelectric member. The pair of piezoelectric members are polarized.

As shown in FIGS. 4 to 9, the end of the actuator 21 facing the nozzle plate 24 has a plurality of grooves 21a, a plurality of wall-shaped drive element portions 21b, and an electrode 21c. The end portion of the actuator 21 is configured in a comb-like shape in which a plurality of grooves 21a and drive element portions 21b are arranged alternately in the longitudinal direction of the actuator 21. That is, a plurality of drive element parts 21b are formed on the end surface of the actuator 21 on the nozzle plate 24 side, and the plurality of drive element parts 21b are spaced apart and adjacent to each other in the X direction, so that there is a gap between the adjacent drive element parts 21b. A groove 21a is formed respectively.

As shown in FIG. 7, the electrode 21c is formed on the inner wall of each groove 21a. For example, each electrode 21c is wired to the drive element section 21b on the actuator 21. Each electrode 21c is electrically connected to the driver IC 43 via, for example, a flexible wiring board 42 (described later) of the plurality of circuit boards 12.

Further, as shown in FIG. 9, the actuator 21 has a channel groove 21d that constitutes a second cooling channel 52b of the cooling device 13, which will be described later.

The pair of cover plates 22 cover the main surface of the actuator 21 in a direction perpendicular to the longitudinal direction of the actuator 21 and in a direction perpendicular to the direction in which the actuator 21 and the nozzle plate 24 face each other. That is, the pair of cover plates 22 cover the main surface of the actuator 21 in the Y direction.

As shown in FIGS. 4 to 8, the cover plate 22 has a plurality of notches 22a formed in the same shape as the groove 21a provided in the actuator 21 in the direction facing the actuator 21. As shown in FIGS. One of the pair of cover plates 22 forms a first cover plate 22A provided on the main surface of the actuator 21 on the primary side in the liquid flow direction along the Y direction within the groove 21a, and the other forms a first cover plate 22A provided on the main surface of the actuator 21 on the primary side in the liquid flow direction along the Y direction within the groove 21a. A second cover plate 22B is provided on the main surface of the actuator 21 on the secondary side in the liquid flow direction along the Y direction.

The plurality of notches 22a face the plurality of grooves 21a provided in the actuator 21 every other time in the direction in which the grooves 21a are arranged. That is, the cover plate 22 opens the openings in the Y direction of every other groove 21a among the plurality of grooves 21a by the notch 22a, and opens the openings in the Y direction of every other groove 21a in the Y direction. is closed by a region where the notch 22a is not provided.

In other words, as shown in FIGS. 5, 7, and 8, the actuator 21 and the cover plate 22 have a plurality of air chambers C1 in which openings at both ends of the groove 21a in the Y direction are closed by a pair of cover plates 22, The notches 22a of the pair of cover plates 22 constitute a plurality of pressure chambers C2 in which openings at both ends of the groove 21a in the Y direction are open. These air chambers C1 and pressure chambers C2 are alternately arranged in parallel along the X direction.

As shown in FIGS. 2 to 6, the channel cover 23 is formed into a plate shape. A pair of channel covers 23 cover the outer surfaces of the actuator 21 and the cover plate 22 in the Y direction.

One of the pair of flow path covers 23 forms a first flow path cover 23A that covers the main surface of the actuator 21 on the primary side and the cover plate 22 in the flow direction of the liquid along the Y direction in the groove 21a. One of the pair of flow path covers 23 forms a second flow path cover 23B that covers the main surface of the actuator 21 on the secondary side and the cover plate 22 in the flow direction of the liquid along the Y direction in the groove 21a.

As shown in FIGS. 4 and 5, the first flow path cover 23A forms a first common chamber C3 communicating with the pressure chamber C2 between the first flow path cover 23A and the first cover plate 22A that covers the actuator 21. The first common chamber C3 extends in the X direction and is fluidly connected to all the pressure chambers C2. The first common chamber C3 communicates with an inflow pipe section 31 of the base plate 11, which will be described later. The first common chamber C3 constitutes an inflow path that communicates the inflow pipe section 31 and the plurality of pressure chambers C2.

As a specific example, the first common chamber C3 communicates with a pair of inflow pipe sections 31 provided on the base plate 11 at both ends in the longitudinal direction. Further, the first common chamber C3 is arranged on the primary side of the plurality of pressure chambers C2, and supplies liquid flowing into the plurality of pressure chambers C2 from the pair of inflow pipe sections 31.

As shown in FIGS. 4 and 5, the second flow path cover 23B forms a second common chamber C4 communicating with the pressure chamber C2 between the second flow path cover 23B and the second cover plate 22B that covers the actuator 21. The second common chamber C4 extends in the X direction and is fluidly connected to all the pressure chambers C2. The second common chamber C4 communicates with an outflow pipe section 32 of the base plate 11, which will be described later. The second common chamber C4 constitutes an outflow path that communicates the plurality of pressure chambers C2 and the outflow pipe section 32.

As a specific example, the second common chamber C4 communicates with a pair of outflow pipe sections 32 provided on the base plate 11 at both ends in the longitudinal direction. Further, the second common chamber C4 is arranged on the secondary side of the plurality of pressure chambers C2, and discharges the liquid flowing out from the plurality of pressure chambers C2 to the pair of outflow pipe sections 32.

As shown in FIGS. 4 to 9, the nozzle plate 24 has a plate shape that is long in one direction. The nozzle plate 24 has, for example, a plurality of nozzles 24a arranged in parallel in the X direction, facing the pressure chamber C2. The nozzle plate 24 includes one or more nozzle rows each including a plurality of nozzles 24a. Each nozzle 24a is a through hole that penetrates between both main surfaces of the nozzle plate 24.

As shown in FIGS. 2 to 6, the base plate 11 is made of a material such as resin or aluminum alloy and has a plate shape. The base plate 11 holds the liquid discharge section 10, the circuit board 12, and the cooling device 13.

In this embodiment, the base plate 11 includes, for example, a pair of first base parts 11a, a pair of second base parts 11b, one third base part 11c, and one base part 11d. The base plate 11 is configured by connecting base parts 11a, 11b, 11c, and 11d.

A circuit board 12 is provided on one main surface of the base plate 11 . Furthermore, a cooling device 13 is provided in a region of the base plate 11 where the circuit board 12 is provided. As a specific example, a part of the base plate 11 is provided so as to be spaced apart in the X direction, and a cooling plate 51 of the cooling device 13, which will be described later, is provided in this spaced apart area.

Further, as shown in FIGS. 2 and 3, the base plate 11 includes an inflow pipe section 31 connected to the primary side of the liquid discharge section 10 and an outflow pipe section 32 connected to the secondary side of the liquid discharge section 10. , is provided. As a specific example, a pair of inflow pipe portions 31 and a pair of outflow pipe portions 32 are provided. The inflow pipe section 31 and the outflow pipe section 32 are provided adjacent to each other.

In this embodiment, one inflow pipe section 31 and one outflow pipe section 32 are provided at both ends of the base plate 11 in the X direction, and the pair of outflow pipe sections 32 are connected to the pair of inflow pipe sections 31. Also arranged on the cooling plate 51 side of the cooling device 13.

As shown in FIGS. 2 and 3, the inflow pipe section 31 is a hole that penetrates the base parts 11a, 11b, 11c, and 11d in the direction that connects the base parts 11a, 11b, 11c, and 11d, in other words, in the Z direction. The first base part 11a includes one inflow channel 31a and a first supply pipe 31b provided in the first base part 11a.

The inflow channel 31a has, for example, a circular channel cross-section perpendicular to the flow direction of the liquid, and is configured to have a constant channel cross-sectional area. The inflow channel 31a is connected to the first supply pipe 31b on the primary side, and communicates with the first common chamber C3 formed in the liquid discharge section 10 on the secondary side. The first supply pipe 31b is connected to the supply tank 132 via a connection channel 133 of the circulation device 2, for example.

As shown in FIGS. 2 and 3, the outflow pipe section 32 includes an outflow channel 32a formed of holes penetrating the base parts 11a, 11b, 11c, and 11d in the Z direction, and an outflow channel 32a provided in the first base part 11a. It has a first discharge pipe 32b.

The outflow channel 32a has, for example, a circular cross-sectional shape perpendicular to the flow direction of the liquid, and has a constant cross-sectional area. The outflow channel 32a may be formed by one hole, or may be formed by a plurality of channels each formed by a plurality of holes. The outflow channel 32a has a secondary side connected to the first discharge pipe 32b, and a primary side communicates with a second common chamber C4 formed in the liquid discharge section 10. The first discharge pipe 32b is connected to the supply tank 132 via a connection channel 133 of the circulation device 2, for example.

As shown in FIGS. 3 to 5, the circuit board 12 includes a control board 41, a plurality of flexible wiring boards 42 provided on the control board 41, and a driver IC 43 provided on each of the flexible wiring boards 42. Be prepared. The control board 41 has a rectangular plate shape, for example. The control board 41 is arranged on one main surface of the base plate 11 in a region where the cooling plate 51 of the cooling device 13 is provided.

A plurality of flexible wiring boards 42 are arranged in parallel in the X direction. The flexible wiring board 42 has one end connected to the control board 41 and the other end connected to the plurality of electrodes 21c of the actuator 21. The driver IC 43 is mounted on the main surface of the flexible wiring board 42 on the side facing the base plate 11 in the Y direction. The driver IC 43 is placed in contact with the cooling plate 51 of the cooling device 13 via, for example, grease or a sheet having high thermal conductivity. The driver IC 43 is electrically connected to the wiring on the control board 41 and the electrode 21c via the flexible wiring board 42.

As shown in FIGS. 2 to 5, the cooling device 13 includes a cooling plate 51, a cooling channel 52, a second supply pipe 53 provided at the primary end of the cooling channel 52, and a cooling channel 52. A second discharge pipe 54 provided at the end of the secondary side of the cooling liquid supply circuit 52 and a coolant supply circuit 55 are provided. The cooling device 13 uses, for example, water as a cooling liquid to cool the members that come into contact with the cooling plate 51, in this embodiment, the components mounted on the control board 41, the driver IC 43, and a part of the liquid discharge section 10.

The cooling plate 51 is made of a metal material with excellent thermal conductivity, such as aluminum material, for example. The cooling plate 51 is, for example, formed in a rectangular shape. The cooling plate 51 contacts at least the driver IC 43. For example, when the cooling plate 51 is placed on the base plate 11, it is formed in a shape that faces the heat-generating electronic components and the driver IC 43 mounted on the control board 41, and comes into contact with the electronic components and the driver IC 43.

The cooling channel 52 is provided in the cooling plate 51 and the liquid discharge part 10, for example. Further, for example, in order to connect a part of the cooling channel 52 provided in the cooling plate 51 and a part of the cooling channel 52 provided in the liquid discharge part 10, the other part of the cooling channel 52 is It is provided on the base plate 11.

As shown in FIG. 3, the cooling channel 52 is close to a first cooling channel 52a formed by holes provided in the cooling plate 51 and a pressure chamber C2 furthest from the inflow pipe section 31 of the actuator 21, for example. It includes a second cooling channel 52b provided in a region including the position, and a third cooling channel 52c that connects the first cooling channel 52a and the second cooling channel 52b.

The first cooling channel 52a has, for example, an end on the primary side and a secondary side facing the liquid discharge part 10 in the Y direction of the cooling plate 51 with the cooling plate 51 disposed on the base plate 11. The end portion is located on the opposite side to the end portion and is arranged on both end sides in the X direction. The first cooling channel 52a extends in the Z direction from one end through a position adjacent to one of the outflow pipe portions 32 toward the end of the cooling plate 51 adjacent to the liquid discharge portion 10, and It extends in the X direction from the end side facing the liquid discharge section 10 . Further, the first cooling channel 52a passes through the center side of the cooling plate 51 at the center side in the X direction of the end facing the liquid discharge part 10 of the cooling plate 51, and further connects to the liquid discharge part 10 of the cooling plate 51. It returns to the opposite end side and extends in the X direction. Further, the first cooling channel 52a extends from the end side of the cooling plate 51 in the X direction to the Z direction through a position adjacent to the other outflow pipe section 32 toward the other end.

As shown in FIGS. 3 and 9, the primary and secondary ends of the second cooling channel 52b are connected to the first cooling channel 52a and the third cooling channel 52c of the cooling plate 51. connected. The second cooling flow path 52b is provided at least in a portion of the actuator 21 at a position away from the inflow pipe portion 31. A portion of the second cooling flow path 52b is arranged close to the pressure chamber C2 that is farthest from the inflow pipe portion 31 of the actuator 21.

Specifically, when a drive voltage is applied to the electrode 21c of the head device 5 and the drive element section 21b is driven, the drive element section 21b and the electrode 21c generate heat, and the liquid passing through the pressure chamber C2 is heated. Therefore, the temperature of the liquid in the liquid discharge section 10 increases as the distance from the inflow pipe section 31 increases.

To explain a specific example, according to the head device 5 of this embodiment, a pair of inflow pipe portions 31 are provided at both ends in the longitudinal direction of the first common chamber C3. Therefore, as shown in FIG. 11, the temperature of the liquid in the liquid discharge section 10 is low at both ends in the longitudinal direction of the liquid discharge section 10, and high at the center. Further, the temperature of the liquid in the liquid discharge section 10 is low on the first common chamber C3 side in the lateral direction of the liquid discharge section 10, and heated in the pressure chamber C2, and high on the second common chamber C4 side.

Therefore, in the head device 5 according to the present embodiment, the temperature of the liquid in the liquid discharge section 10 is highest at the center in the longitudinal direction of the second common chamber C4.

Therefore, as shown in FIG. 3, FIG. 8, and FIG. 9, the second cooling channel 52b is, for example, a channel groove provided on the main surface of the actuator 21 facing the second channel cover 23B in the Y direction. 21d and a second cover plate 22B that covers the channel groove 21d. In addition, the second cooling flow path 52b includes, for example, a pressure chamber C2 furthest from the pair of inflow pipe sections 31 of the second cooling flow path 52b and several adjacent pressure chambers C2 furthest from the pair of inflow pipe sections 31. The portion facing the pressure chamber C2 is closest to the pressure chamber C2 than other portions of the second cooling flow path 52b.

As a specific example, as shown in FIG. 9, the channel grooves 21d of the actuator 21 constituting the second cooling channel 52b include a plurality of first grooves 21d1 along the Z direction and a plurality of second grooves along the X direction. 21d2 and one third groove 21d3. The plurality of second grooves 21d2 and one third groove 21d3 are provided at two positions at different distances in the Z direction from the end of the actuator 21 facing the cooling plate 51. The third groove 21d3 is provided at a position farther from the end of the actuator 21 facing the cooling plate 51 than the second groove 21d2 in the Z direction. The third groove 21d3 is provided in a range facing several pressure chambers C2 including the pressure chamber C2 furthest from at least one pair of inflow pipe portions 31 in the center of the actuator 21.

As shown in FIG. 3, the third cooling channel 52c is provided on the primary side and the secondary side of the second cooling channel 52b, respectively. A pair of third cooling channels 52c fluidly connects the first cooling channel 52a and the second cooling channel 52b. For example, the pair of third cooling channels 52c are configured by holes formed in the third base part 11c and the fourth base part 11d of the base plate 11. Note that the shape and arrangement of the cooling channel 52 are set as appropriate.

The second supply pipe 53 and the second discharge pipe 54 are fixed to the base 51a and connected to one end and the other end of the first cooling channel 52a. The second supply pipe 53 and the second discharge pipe 54 are connected to, for example, a coolant supply circuit 55. The coolant supply circuit 55 includes, for example, a flow path such as a pipe or a tube for supplying the coolant, and a pump.

Next, a liquid ejection apparatus 100 having the liquid ejection head 1 will be described using FIG. 10. As shown in FIG. 10, the liquid ejection apparatus 100 includes a housing 111, a medium supply section 112, an image forming section 113, a medium discharge section 114, a transport device 115 as a support device, a control section 116, Equipped with

The liquid ejection device 100 is, for example, an inkjet printer. The liquid ejection apparatus 100 transports, for example, a paper P as a recording medium, which is an object to be ejected, along a predetermined transport path A1 from a medium supply section 112 through an image forming section 113 to a medium discharge section 114. Then, the liquid ejection device 100 performs an image forming process on the transported paper P by ejecting ink as a liquid.

The medium supply unit 112 includes a plurality of paper feed cassettes 112a. The medium discharge section 114 includes a paper discharge tray 114a. The image forming section 113 includes a support section 117 that supports paper, and a plurality of head units 130 arranged above the support section 117 and facing each other.

The support unit 117 includes a conveyor belt 118 provided in a loop shape in a predetermined area where image formation is performed, a support plate 119 that supports the conveyor belt 118 from the back side, and a plurality of belt rollers 120 provided on the back side of the conveyor belt 118. , is provided.

The head unit 130 includes a liquid ejection head 1, which is a plurality of liquid ejection heads, and a circulation device 2. The circulation device 2 includes, for example, a plurality of supply tanks 132 as liquid tanks mounted on each liquid ejection head 1, a connection channel 133 connecting the liquid ejection head 1 and the supply tank 132, and a circulation section. A certain circulation pump 134 is provided. The head unit 130 is a circulation type head unit that circulates liquid.

In this embodiment, the liquid ejection head 1 includes liquid ejection heads 1C, 1M, 1Y, and 1B that eject ink of four colors cyan, magenta, yellow, and black as liquid, and a supply tank that accommodates the ink of each of these colors. As 132, supply tanks 132C, 132M, 132Y, and 132B are provided. The supply tank 132 is connected to the liquid ejection head 1 by a connection channel 133. The connection channel 133 includes a supply channel 133a connected to the inflow pipe section 31 of the liquid ejection head 1, and a recovery channel 133b connected to the outflow pipe section 32 of the liquid ejection head 1.

Further, a negative pressure control device such as a pump (not shown) is connected to the supply tank 132. The liquid supplied to each nozzle 24a of the liquid ejection head 1 is then It is formed into a meniscus of a predetermined shape.

The circulation pump 134 is, for example, a liquid pump made up of a piezoelectric pump. The circulation pump 134 is provided in the supply channel 133a. The circulation pump 134 is connected to the control unit 116 by wiring, and is configured to be controllable under the control of a CPU (Central Processing Unit) 116a. The circulation pump 134 circulates the liquid in a circulation flow path that includes the liquid discharge head 1 and the supply tank 132.

The transport device 115 transports the paper P along a transport path A1 from the paper feed cassette 112a of the medium supply section 112 through the image forming section 113 to the paper discharge tray 114a of the medium discharge section 114. The conveyance device 115 includes a plurality of guide plate pairs 121a to 121h arranged along the conveyance path A1 and a plurality of conveyance rollers 122a to 122h. The transport device 115 supports the paper P so as to be movable relative to the liquid ejection head 1 .

The control unit 116 includes a CPU (central control unit) 116a as an example of a processor, a ROM (Read Only Memory) that stores various programs, and a RAM (RAM) that temporarily stores various variable data, image data, etc. Random Access Memory), and an interface unit that inputs data from the outside and outputs data to the outside.

According to the liquid ejection head 1 and the liquid ejection device 100 configured in this way, the circulation pump 134 of the circulation device 2 is driven, so that the liquid is transferred from the supply tank 132 and the connection channel 133 to the inflow pipe section 31. and reaches the plurality of pressure chambers C2 through the first common chamber C3.

When ejecting liquid from the nozzle 24a, the control section 116 controls the driver IC 43, applies a drive voltage to the drive element section 21b, and ejects the liquid from the nozzle 24a. As a specific example, the driver IC 43 applies a driving voltage to the electrodes 21c provided in the plurality of grooves 21a of the actuator 21. At this time, the driver IC 43 applies a potential difference between the electrode 21c in the pressure chamber C2 to be driven and the electrodes 21c in the air chambers C1 on both sides. Then, as shown in one drive element section 21b in FIG. 7, the pair of piezoelectric materials forming the actuator 21 are deformed in opposite directions, and the drive element section 21b is bent and deformed. The driver IC 43 increases or decreases the volume of the pressure chamber C2 by alternately repeating bending deformation in different directions, and discharges liquid as droplets from the nozzle 24a facing the pressure chamber C2.

Further, the liquid that has not been discharged from the nozzle 24a is collected from the pressure chamber C2 into the supply tank 132 through the second common chamber C4, the outflow pipe section 32, and the connection channel 133. In this way, the liquid supplied to the liquid ejection head 1 circulates within the circulation device 2 and the liquid ejection head 1.

Note that when a drive voltage is applied to the electrode 21c and the drive element section 21b is driven, the drive element section 21b and the electrode 21c generate heat, so that the liquid passing through the pressure chamber C2 is heated. However, the liquid ejection head 1 of the present embodiment is configured to include a second cooling flow path 52b that flows through the actuator 21 of the liquid ejection section 10 as a part of the cooling flow path 52 through which the cooling liquid of the cooling device 13 flows.

Therefore, the cooling device 13 cools the actuator 21 and the second cover plate 22B by passing the cooling liquid through the second cooling channel 52b. Thereby, the liquid ejection head 1 can cool the liquid in the area including the farthest position from the pair of inflow pipe sections 31 and the pressure chamber C2 and the second common chamber C4 in this area.

Therefore, the liquid on the discharge surface, which is the surface of the nozzle plate 24, in some pressure chambers C2 located far from the inflow pipe section 31 among the plurality of pressure chambers C2 is cooled, and the liquid on the discharge surface of the plurality of discharge surfaces is cooled. The difference between the maximum and minimum liquid temperature can be reduced. In this way, the liquid ejection head 1 can equalize the temperature of the liquid on the ejection surfaces of the plurality of pressure chambers C2 and reduce the temperature of the liquid. As a result, the liquid ejection head 1 can suppress viscosity differences due to variations in the temperature of the liquid (ink) on the ejection surface in the plurality of pressure chambers C2, and can prevent the high definition of printing from deteriorating.

In addition, since the liquid that becomes high temperature in the liquid discharge section 10 is cooled by the cooling device 13, the liquid discharge head 1 is connected to the circulation device 2, and in the liquid discharge device 100 that circulates the liquid, the liquid returns to the supply tank 132. The temperature of the liquid can be reduced. Therefore, even when the liquid is circulated by the circulation device 2, it is possible to suppress the temperature of the liquid from increasing. In addition, the cooling device 13 can also cool the electrical components of the control board 41 and the driver IC 43 using the cooling plate 51.

As described above, according to the liquid ejection head 1 and the liquid ejection apparatus 100 according to one embodiment, the temperature of the liquid in the liquid ejection section 10 can be equalized. To be more specific, the cooling channel 52 of the cooling device 13 is located in the pressure chamber C2 furthest from the inflow pipe section 31 in the liquid discharge section 10 and in a region close to several pressure chambers C2 close to this pressure chamber C2. It has a third groove 21d3 through which the cooling liquid passes. Therefore, the cooling device 13 can cool a region of the liquid discharging section 10 that includes a position farthest from the inflow pipe section 31 of the liquid discharging section 10 where the temperature of the liquid is relatively high. As a result, the liquid whose temperature is relatively high on the plurality of discharge surfaces is cooled. Therefore, the liquid ejection head 1 and the liquid ejection apparatus 100 can equalize the temperature of the liquid on the ejection surfaces of the plurality of pressure chambers C2, and can reduce the temperature of the liquid.

It should be noted that the present invention is not limited to the above-described embodiments as they are, but can be implemented by modifying the constituent elements within the scope of the invention at the implementation stage.

In the example described above, the head device 5 of the liquid ejection head 1 has a configuration having a pair of inflow pipe sections 31 and a pair of outflow pipe sections 32, but the present invention is not limited to this. For example, it may be configured to have one inflow pipe section 31 and one outflow pipe section 32, like a head device 5A of a liquid ejection head 1 according to another embodiment shown in FIG. In the case of the head device 5A having such a configuration, since the temperature of the liquid is high at the end of the second flow path cover 23B farthest from the inflow pipe portion 31, the second cooling flow path of the cooling device 13 is 52b may be brought closer to a part of the pressure chamber C2 on the end side opposite to the inflow pipe part 31 in the X direction of the actuator 21, which is farthest from one inflow pipe part 31. Furthermore, instead of arranging one inflow pipe section 31 and one outflow pipe section 32 adjacent to each other, one inflow pipe section 31 is arranged at one end in the longitudinal direction of the liquid discharge section 10, and one inflow pipe section 31 is arranged at the other end in the longitudinal direction of the liquid discharge section 10. It is also possible to have a configuration in which one outflow pipe section 32 is provided.

Further, in the above-described example, the second cooling flow path 52b is configured by the flow path groove 21d provided in the actuator 21 and the second cover plate 22B, but the present invention is not limited thereto. For example, the second cooling flow path 52b may be provided in the second flow path cover 23B.

Further, for example, in the above-described example, the liquid ejection head 1 is configured to have a plurality of head devices 5, but the present invention is not limited to this, and the liquid ejection head 1 is configured to include only one head device 5. Good too.

According to at least one embodiment described above, it is possible to provide a liquid ejection head and a liquid ejection apparatus that can uniformize the temperature of liquid.

Although several embodiments of the invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention, as well as within the scope of the invention described in the claims and its equivalents.
Below, descriptions equivalent to the invention stated in the original claims of the present application will be added.
[1] A liquid ejection unit including a first common chamber, an actuator forming a plurality of pressure chambers connected to the first common chamber, and a second common chamber connected to the plurality of pressure chambers;
an inflow pipe section that supplies liquid to the first common chamber;
an outflow pipe section for discharging the liquid from the second common chamber;
a cooling device including a cooling plate, and a cooling flow path provided in a portion of the liquid discharge portion closest to the pressure chamber farthest from the inflow pipe portion and the cooling plate and through which the cooling liquid passes;
A liquid ejection head comprising:
[2] The part of the liquid discharge part that is closest to the pressure chamber that is farthest from the inflow pipe part is a part that includes the position that is closest to the pressure chamber that is farthest from the inflow pipe part of the actuator. The liquid ejection head described in ].
[3] The liquid ejection head according to [1] or [2], wherein the cooling channel provided in the actuator is a groove provided on the second common chamber side of the actuator.
[4] a cover plate that covers the groove provided on the second common chamber side of the actuator;
a channel cover that covers the actuator and the cover plate and forms the second common chamber;
The liquid ejection head according to [3], comprising:
[5] The liquid ejection head according to any one of [1] to [4], wherein the cooling plate contacts a driver IC that drives the actuator.
[6] The liquid ejection head according to any one of [1] to [5], including a plurality of head devices in which the liquid ejection section, the inflow pipe section, the outflow pipe section, and the cooling device are integrally assembled. .
[7] A liquid discharge section including a first common chamber, an actuator forming a plurality of pressure chambers connected to the first common chamber, and a second common chamber connected to the plurality of pressure chambers; an inflow pipe section that supplies liquid to the first common chamber; an outflow pipe section that discharges liquid from the second common chamber; a cooling plate; a cooling device including a cooling channel provided on the cooling plate and through which a cooling liquid passes;
a support device that supports an object to which the liquid is to be ejected;
A liquid ejection device comprising:

DESCRIPTION OF SYMBOLS 1...Liquid discharge head, 2...Circulation device, 4...Outer case, 5...Head device, 10...Liquid discharge part, 11...Base plate, 11a...First base part, 11b...Second base part, 11c...Third base Parts, 11d... Fourth base part, 12... Circuit board, 13... Cooling device, 21... Actuator, 21a... Groove, 21b... Drive element section, 21c... Electrode, 21d... Channel groove, 21d1... First groove, 21d2...Second groove, 21d3...Third groove, 22...Cover plate, 22A...First cover plate, 22B...Second cover plate, 22a...Notch, 23...Flow path cover, 23A...First flow path cover, 23B ...Second channel cover, 24...Nozzle plate, 24a...Nozzle, 31...Inflow pipe section, 31a...Inflow channel, 31b...First supply pipe, 32...Outflow pipe section, 32a...Outflow channel, 32b...First 1 exhaust pipe, 41... control board, 42... flexible wiring board, 51... cooling plate, 51a... base, 52... cooling channel, 52a... first cooling channel, 52b... second cooling channel, 52c... third Cooling channel, 53... Second supply pipe, 54... Second discharge pipe, 55... Coolant supply circuit, 100... Liquid discharge device, 111... Housing, 112... Medium supply unit, 112a... Paper feed cassette, 113... Image forming section, 114... Medium discharge section, 114a... Paper discharge tray, 115... Conveyance device, 116... Control section, 117... Support section, 118... Conveyance belt, 119... Support plate, 120... Belt roller, 130... Head unit , 132... Supply tank, 133... Connection flow path, 133a... Supply flow path, 133b... Recovery flow path, 134... Circulation pump, C1... Air chamber, C2... Pressure chamber, C3... First common chamber, C4... Second Common room, P...Paper.

Claims (6)

a liquid ejection unit including a first common chamber, an actuator that configures a plurality of pressure chambers connected to the first common chamber, and a second common chamber connected to the plurality of pressure chambers;
an inflow pipe section that supplies liquid to the first common chamber;
an outflow pipe section for discharging the liquid from the second common chamber;
a cooling device including a cooling plate and a cooling channel through which a cooling liquid passes;
Equipped with
The direction along the longitudinal direction of the actuator is the X direction, the direction in which the first common chamber and the second common chamber face each other via the pressure chamber is the Y direction, and the direction perpendicular to the X direction and the Y direction is the direction. When in the Z direction,
The plurality of pressure chambers are provided in line along the X direction at one end of the actuator in the Z direction,
The cooling channel includes a first cooling channel provided in the cooling plate and a second cooling channel provided in the actuator,
The second cooling flow path is provided such that the pressure chamber side furthest from the inflow pipe section side in the X direction is closer to the pressure chamber in the Z direction than the inflow pipe section side in the X direction. , liquid ejection head. The liquid ejection head according to claim 1, wherein the second cooling channel is a groove fluidly connected to the first cooling channel and provided on the second common chamber side of the actuator. a cover plate that covers the groove provided on the second common chamber side of the actuator;
a channel cover that covers the actuator and the cover plate and forms the second common chamber;
The liquid ejection head according to claim 2, comprising: The liquid ejection head according to any one of claims 1 to 3, wherein the cooling plate contacts a driver IC that drives the actuator. The liquid ejection head according to any one of claims 1 to 4, comprising a plurality of head devices in which the liquid ejection section, the inflow pipe section, the outflow pipe section, and the cooling device are integrally assembled. a liquid discharge section including a first common chamber, an actuator forming a plurality of pressure chambers connected to the first common chamber, and a second common chamber connected to the plurality of pressure chambers, and the first common chamber. a liquid discharge head comprising: an inflow pipe section for supplying liquid to the second common chamber; an outflow pipe section for discharging the liquid from the second common chamber; and a cooling device including a cooling plate and a cooling channel through which the cooling liquid passes. ,
a support device that supports an object to which the liquid is to be ejected;
Equipped with
The direction along the longitudinal direction of the actuator is the X direction, the direction in which the first common chamber and the second common chamber face each other via the pressure chamber is the Y direction, and the direction perpendicular to the X direction and the Y direction is the direction. When in the Z direction,
The plurality of pressure chambers are provided in line along the X direction at one end of the actuator in the Z direction,
The cooling channel includes a first cooling channel provided in the cooling plate and a second cooling channel provided in the actuator,
The second cooling flow path is provided such that the pressure chamber side furthest from the inflow pipe section side in the X direction is closer to the pressure chamber in the Z direction than the inflow pipe section side in the X direction. , liquid ejection device.