Liquid ejection head and liquid ejection apparatus

Abstract

The invention provides a liquid ejecting head and a liquid ejecting apparatus capable of suppressing a water attack phenomenon. A liquid ejection head according to an embodiment includes a nozzle plate and a liquid flow path. The nozzle plate has nozzles. The liquid flow path has a plurality of actuator grooves that constitute pressure chambers that communicate with the plurality of nozzles, and one or more common flow paths that extend in the first direction and communicate with the plurality of actuator grooves, and the liquid flow path has a supply port to which a liquid is supplied. When the thickness of the nozzle plate is Tmm, the relationship between the maximum supply distance Lmm, which is the distance in the first direction from a supply unit that supplies liquid to the common flow path to the farthest actuator groove in the common flow path, and the flow path width Wmm, which is the dimension of the common flow path in a second direction that intersects the first direction, satisfies # imgabs0 # nozzle plate is configured from a flexible film. And the Young's modulus is 9.1 Gpa or more.

Description

Technical Field

[0001] Embodiments of the present invention relate to a liquid ejection head and a liquid ejection device. Background Art

[0002] Liquid ejection devices such as inkjet printers are required to be small and have a large ink ejection volume and high productivity. Therefore, there is a device that ensures the ink flow rate and corresponds to high productivity by supplying ink from both sides of the actuator groove of the side-injection type inkjet head. In order to miniaturize the liquid ejection head, restrictions are set on the size of the ink flow path that supplies ink. On the other hand, when the state of switching from a large ink flow rate flowing in the head to a small ink flow rate printing due to the size of the ink flow path, water hammer phenomenon (water hammer phenomenon) sometimes occurs, which affects the stability of the curved liquid surface required for stable ejection. Summary of the invention

[0003] Technical problem to be solved by the invention

[0004] The technical problem to be solved by the present invention is to provide a liquid ejection head and a liquid ejection device capable of suppressing the water hammer phenomenon.

[0005] Solutions for solving technical problems

[0006] The liquid ejection head involved in the embodiment includes a nozzle plate and a liquid flow path. The nozzle plate has a nozzle. The liquid flow path has a plurality of actuator grooves constituting pressure chambers respectively connected to the plurality of nozzles and one or more common flow paths extending along a first direction and connected to the plurality of actuator grooves, and the liquid flow path has a supply port to which liquid is supplied. When the thickness of the nozzle plate is Tmm, the distance in the first direction from the supply portion for supplying liquid to the common flow path to the farthest actuator groove in the common flow path, i.e., the maximum supply distance Lmm, and the dimension of the common flow path in a second direction intersecting the first direction, i.e., the flow path width Wmm, satisfy the relationship:

[0007] L≥(-372.02T+26.0415)W 2 +(47.616T-4.7618)W+7.1429

[0008] …(Formula 1).

[0009] The nozzle plate is formed of a flexible film and has a Young's modulus of 9.1 GPa or more. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a perspective view showing the structure of the liquid ejecting head according to the first embodiment.

[0011] Figure 2It is a perspective view showing the structure of a head main body of the liquid ejecting head.

[0012] Figure 3 It is a bottom view showing the structure of the same liquid ejection head.

[0013] Figure 4 It is a cross-sectional view showing a partial structure of the same liquid ejecting head.

[0014] Figure 5 It is a cross-sectional view showing a partial structure of the same liquid ejecting head.

[0015] Figure 6 It is an explanatory diagram showing the structure of the flow path of the same liquid ejection head.

[0016] Figure 7 It is an explanatory diagram showing the structure of the liquid ejecting device according to the embodiment.

[0017] Figure 8 It is an explanatory diagram showing the structure of a flow path of a liquid ejection head according to another embodiment.

[0018] Fig. 9 It is an explanatory diagram showing the structure of a flow path of a liquid ejection head according to another embodiment.

[0019] Description of Reference Numerals

[0020] 1: liquid ejection head; 2: liquid ejection device; 11: head body; 12: manifold unit; 15: cover; 16: ink flow path (liquid flow path); 111: substrate; 112: frame; 113: actuator; 114: nozzle plate; 116: common flow path portion; 117: supply portion; 121: manifold; 123: ink supply pipe; 1111: supply port; 1131: pressure chamber; 1132: air chamber; 1133: piezoelectric body; 1134: inclined surface; 1135: actuator groove; 1141: nozzle; 1142: nozzle array; 1161: first common flow path; 1162: second common flow path (common flow path); 1211: supply path; 2001: conveying path; 2111: casing; 2112: medium supply unit; 2113: image forming unit; 2114: medium discharge unit; 2115: conveying device; 2116: cooling device; 2117: maintenance device; 2118: control unit; 2120: support unit; 2130: head unit; 2132: supply tank; 2134: pump; 2135: connecting flow path; 21121: paper supply box; 21141: paper discharge tray; 21181: CPU; 21201: conveyor belt; 21202: support plate; 21203: belt roller; 21211~21218: guide plate pair; 21221~21228: conveying roller. DETAILED DESCRIPTION

[0021] Refer to the following Figures 1 to 7 A liquid ejecting head 1 according to a first embodiment and a liquid ejecting apparatus 2 using the liquid ejecting head 1 will be described. Figure 1 2 is a perspective view showing the structure of the liquid ejection head according to the present embodiment. Figure 2 It is a perspective view showing the structure of the head body. Figure 3 2 is a bottom view showing the structure of the liquid ejection head. Figure 4 It is a cross-sectional view showing a partial structure of the liquid ejecting head. Figure 5 2 is a cross-sectional view showing a partial structure of the same liquid ejection head. Figure 6 This is an explanatory diagram showing the structure of the flow path of the liquid ejection head. Figure 7 The following is an explanatory diagram showing the structure of the liquid ejection device involved in the present embodiment. In the figure, X, Y, and Z respectively show a first direction, a second direction, and a third direction that are orthogonal to each other. It should be noted that in each figure, for the sake of convenience of explanation, the structure will be appropriately shown in an enlarged, reduced, or omitted manner.

[0022] The liquid ejection head 1 is provided, for example, at Figure 7 The inkjet head of the shared mode of the liquid ejection device 2 such as the inkjet recording device shown. The liquid ejection head 1 is, for example, an independently driven structure that alternately includes a pressure chamber 1131 and an air chamber 1132. The liquid ejection head 1 is provided in a head unit 2130, and the head unit 2130 includes a supply tank 2132 as a liquid storage portion provided in the liquid ejection device 2.

[0023] The liquid ejection head 1 is supplied with ink as a liquid stored in the supply tank 2132. It should be noted that the liquid ejection head 1 may be a non-circulating head that does not circulate the ink, or a circulating head that circulates the ink. In this embodiment, the liquid ejection head 1 is described using an example of a non-circulating head.

[0024] like Figures 1 to 7 As shown, the liquid ejection head 1 includes a head body 11, a manifold unit 12, and a cover 15. For example, the liquid ejection head 1 is a side-shooter type four-row integrated structure head having two sets of head bodies 11 each having a pair of actuators 113.

[0025] The head body 11 ejects liquid. The head body 11 includes a substrate 111, a frame 112, an actuator 113 having a plurality of pressure chambers 1131 and a plurality of air chambers 1132, and a nozzle plate 114. A predetermined ink flow path 16 is formed inside the head body 11, passing through the pressure chamber 1131 communicating with the nozzle 1141. The ink flow path 16 is a liquid flow path.

[0026] As a part of the ink flow path 16, the head body 11 has a common flow path portion 116 that communicates with the plurality of pressure chambers 1131 of the actuator 113. The primary side of the plurality of pressure chambers 1131 refers to the upstream side of the plurality of pressure chambers 1131 in the direction of liquid flow. The secondary side of the plurality of pressure chambers 1131 refers to the downstream side of the plurality of pressure chambers 1131 in the direction of liquid flow.

[0027] In addition, the head body 11 has an electrode portion composed of an electrode film formed on the substrate 111 and the actuator 113. Specifically, the head body 11 has a plurality of individual electrodes for driving the plurality of pressure chambers 1131 of the actuator 113, and a single or multiple common electrodes for driving the plurality of pressure chambers 1131 simultaneously as the electrode portion.

[0028] In the example of the present embodiment, the head body 11 includes two actuators 113, and the common flow path portion 116 includes one first common flow path 1161 and two second common flow paths 1162. The common flow path portion 116 includes, for example, the first common flow path 1161 communicating with one opening of the plurality of pressure chambers 1131 of the actuator 113 (the inlet of the pressure chamber 1131), and the second common flow path 1162 communicating with the secondary opening of the plurality of pressure chambers 1131 of the actuator 113 (the outlet of the pressure chamber 1131).

[0029] That is, the first common flow path 1161 is arranged on one end side of the plurality of actuator grooves 1135 extending in the second direction (Y direction), and the second common flow path 1162 is arranged on the other end side of the actuator grooves 1135 in the pair of actuators 113. In addition, the first common flow path 1161 and the second common flow path 1162 are connected to each other through both ends in the first direction.

[0030] The substrate 111 is formed into a rectangular plate shape by a ceramic material such as alumina. The substrate 111 is formed into a rectangular shape that is long in one direction (X direction), for example. The electrode film is formed on a surface that is a main surface of one side of the substrate 111 and constitutes a grinding surface. A pair of actuators 113 are arranged on the surface of the substrate 111 in a manner arranged along the short side direction (Y direction) of the substrate 111. The substrate 111 has a single supply port 1111 as an opening for liquid to pass through. The supply port 1111 is a through hole that passes through the two main surfaces of the substrate 111.

[0031] It should be noted that the inner surface of the substrate 111 faces the manifold 121 and covers a groove forming a cooling flow path formed on the surface facing the manifold 121 and through which cooling water flows. That is, the substrate 111 and the manifold 121 together form a cooling flow path.

[0032] The supply port 1111 is an inlet for supplying ink to the first common flow path 1161. The supply port 1111 is a through hole formed in the center of the substrate 111 in the short side direction. The supply port 1111 extends along the length direction of the substrate 111. In other words, the supply port 1111 is, for example, a long hole that is long in one direction along the length direction of the actuator 113 and the length direction of the first common flow path 1161. The supply port 1111 is provided between the pair of actuators 113 and opens at a position opposite to the first common flow path 1161. A portion of the common electrode may also be formed on the inner wall surface of the supply port 1111.

[0033] An actuator 113 and a frame 112 are provided on the substrate 111. The inside of the frame 112 in the substrate 111 is a liquid contact area where ink is arranged, and the outside of the frame 112 in the substrate 111 is a mounting area where various electronic components can be connected.

[0034] The frame 112 is fixed to one main surface of the substrate 111 by an adhesive or the like. The frame 112 surrounds the supply port 1111 and the actuator 113 provided on the substrate 111 .

[0035] For example, the frame 112 is formed into a rectangular frame shape to form an opening that is long in one direction along the length direction of the frame 112. The frame 112 may also have a step structure in which a portion of the surface is recessed. A pair of actuators 113 and a supply port 1111 are arranged at the opening of the frame 112. The frame 112 surrounds the actuator 113 between the nozzle plate 114 and the substrate 111, and is configured to be able to hold the liquid inside. That is, a prescribed ink flow path including a pressure chamber 1131, common flow paths 1161, 1162 is formed in the head body 11 by the frame 112, the nozzle plate 114, the substrate 111, and the actuator 113.

[0036] A pair of actuators 113 are bonded to the surface of the substrate 111. A pair of actuators 113 are arranged in two rows on the substrate 111 with the supply port 1111 sandwiched therebetween. The actuators 113 are plate-shaped components that are long in one direction. The actuators 113 are arranged in the opening of the frame 112 and bonded to the surface of the substrate 111.

[0037] The actuator 113 has a plurality of pressure chambers 1131 arranged at equal intervals in the longitudinal direction and air chambers 1132 arranged at equal intervals in the longitudinal direction and arranged between adjacent pressure chambers 1131 on the central side in the longitudinal direction. In other words, the plurality of pressure chambers 1131 and the air chambers 1132 are alternately arranged in the longitudinal direction of the actuator 113. The plurality of pressure chambers 1131 and the plurality of air chambers 1132 extend in a direction intersecting the arrangement direction, for example, in the short side direction of the actuator 113.

[0038] The top surface portion of the actuator 113, which is the surface on the side opposite to the substrate 111, is bonded to the nozzle plate 114. A plurality of actuator grooves 1135 are formed in the actuator 113, which are arranged at equal intervals in the longitudinal direction and along a direction perpendicular to the longitudinal direction. The plurality of actuator grooves 1135 form a plurality of pressure chambers 1131 and a plurality of air chambers 1132. In other words, the actuator 113 has a plurality of piezoelectric bodies 1133 arranged at equal intervals in the longitudinal direction, and the piezoelectric bodies 1133 are driving elements constituting the walls that form the actuator grooves 1135 at intervals. The plurality of piezoelectric bodies 1133 form a plurality of pressure chambers 1131 and a plurality of air chambers 1132 between adjacent piezoelectric bodies 1133, and the volume of the pressure chamber 1131 is changed by applying a driving voltage.

[0039] In the actuator 113, for example, the width in the short-side direction gradually increases from the top side toward the substrate 111 side. The cross-sectional shape of the actuator 113 along the direction (short-side direction) perpendicular to the longitudinal direction forms a trapezoidal shape. That is, the actuator 113 has an inclined surface 1134 on the side portion in the short-side direction. The side portion (inclined surface 1134) is arranged opposite to the first common flow path 1161 and the second common flow path 1162. The electrode film is formed on the inclined surface 1134 in a predetermined pattern.

[0040] As a specific example, the actuator 113 is formed by a stacked piezoelectric component, which is formed by bonding two rectangular plate-shaped piezoelectric materials that are longer in one direction in a manner that their polarization directions are opposite to each other. Here, the piezoelectric material is, for example, PZT (lead zirconate titanate). The actuator 113 is bonded to the surface of the substrate 111 by, for example, an adhesive. In addition, the actuator 113 has an inclined surface 1134. In the actuator 113, a plurality of actuator grooves 1135 are formed, and the plurality of actuator grooves 1135 form a plurality of pressure chambers 1131 and a plurality of air chambers 1132, and form a piezoelectric body (driving element) 1133 as a side wall that divides adjacent actuator grooves 1135.

[0041] In addition, an electrode film constituting an individual electrode and a common electrode is formed in a predetermined pattern on the actuator 113 .

[0042] The pressure chamber 1131 is deformed when the liquid ejection head 1 performs printing or other operations, so that the ink is ejected from the nozzle 1141. The inlet of the pressure chamber 1131 opens to the first common flow path 1161, and the outlet opens to the second common flow path 1162. The ink of the pressure chamber 1131 flows in from the inlet, and the ink flows out from the outlet. It should be noted that the pressure chamber 1131 may also be a structure in which the ink flows in from two openings described as the inlet and the outlet. The individual electrodes are respectively formed in the actuator grooves 1135 constituting the pressure chamber 1131.

[0043] The air chamber 1132 is separated from the first common flow path 1161 and the second common flow path 1162 by blocking the inlet and outlet sides with a liquid-proof wall formed of a photosensitive resin or the like. In the actuator groove 1135 forming the air chamber 1132, after injecting an ultraviolet curing resin onto the electrode, the liquid-proof wall of the air chamber 1132 is formed by irradiating ultraviolet light to the area to be exposed, for example, both ends of the inlet and outlet sides of the actuator groove 1135 using an exposure mask or the like. Such a liquid-proof wall prevents the ink from invading the air chamber 1132. In addition, the air chamber 1132 is blocked by the nozzle plate 114, and the nozzle 1141 is not arranged. Therefore, the ink does not flow into the air chamber 1132.

[0044] The nozzle plate 114 is formed in a plate shape. The nozzle plate 114 is made of a flexible film such as a polyimide film. The Young's modulus of the nozzle plate 114 is greater than 9.1 GPa. The nozzle plate 114 is arranged opposite to one side of the actuator 113 in the third direction (Z direction). For example, when the pressure of the opposing pressure chamber 1131 changes, the nozzle plate 114 functions as a pressure buffer damper. The nozzle plate 114 is fixed to the surface of the frame 112 on the side opposite to the substrate 111 by an adhesive or the like. The nozzle plate 114 has a plurality of nozzles 1141 formed at positions opposite to the plurality of pressure chambers 1131. In the present embodiment, the nozzle plate 114 has two rows of nozzle columns 1142 formed by a plurality of nozzles 1141 arranged in one direction.

[0045] The first common flow path 1161 is formed between the central sides of the pair of actuators 113 excluding both ends, and constitutes a flow path of ink from the supply port 1111 to the opening (inlet) of the primary side of the plurality of pressure chambers 1131 of each actuator 113. The first common flow path 1161 extends along the longitudinal direction of the actuator 113. The first common flow path 1161 constitutes a part of the ink flow path 16.

[0046] The second common flow path 1162 is formed between each actuator 113 and the frame 112. The second common flow path 1162 forms a flow path of ink starting from the opening (outlet) on the secondary side of the plurality of pressure chambers 1131. The second common flow path 1162 extends along the longitudinal direction of the actuator 113. The second common flow path 1162 constitutes a part of the ink flow path 16.

[0047] In the liquid ejection head 1, as in Figure 6, the ink flows to the second common flow path 1162 as the side flow path, the liquid flows into the supply port 1111, and flows from the central first common flow path 1161 through the outer sides of both ends of the actuator 113 in the first direction to the second common flow path 1162. That is, the ink supplied from the supply port 1111 passes through the first common flow path 1161 as the central flow path close to the supply port 1111 and the second common flow path 1162 as the side flow path away from the supply port 1111, and the ink is supplied to the actuator groove 1135 forming the pressure chamber 1131 from both sides of the Y direction as the extension direction of the actuator groove 1135.

[0048] That is, the inlet of the actuator groove 1135 located at the center of the arrangement direction of the side flow path on the opposite side sandwiching the supply port 1111 and the actuator 113 becomes the inlet of the actuator groove 1135 at the farthest position from the supply port 1111.

[0049] When the thickness of the nozzle plate in the Z direction is Tmm, when the distance in the first direction from the supply unit 117 for supplying liquid to the second common flow path 1162 to the farthest actuator groove 1135 is set to the maximum supply distance Lmm, and the width dimension of the second common flow path 1162 in the second direction is set to the flow path width Wmm, the relationship between L, T and W satisfies:

[0050] L≥(-372.02T+26.0415)W 2 +(47.616T-4.7618)W+7.1429

[0051] …(Formula 1).

[0052] It should be noted that if Figure 5 As shown, when the shape is such that the width varies according to the depth direction, the width dimension W of the cross section of the second common flow path 1162 in the second direction is set to the width dimension of the portion of the second common flow path 1162 facing the nozzle plate 114.

[0053] For example, when the supply port 1111 is arranged at a position different from the second common flow path 1162, the supply portion 117 is set as the end of the primary side of the second common flow path 1162. That is, the end of the actuator 113 in the first direction (X direction) and the connecting portion that becomes the entrance for the liquid to flow into the second common flow path 1162 is set as the supply portion 117, and the maximum supply distance L becomes the distance from the supply portion 117 to the actuator groove 1135 at the farthest position.

[0054] The plurality of individual electrodes individually apply driving voltages to the plurality of piezoelectric bodies 1133 as driving elements. The plurality of individual electrodes individually deform the pressure chambers 1131. The individual electrodes are formed by a wiring pattern formed on the substrate 111 and a wiring pattern formed on the actuator 113.

[0055] The common electrode applies the same driving voltage to all the plurality of piezoelectric bodies 1133. The common electrode simultaneously deforms the plurality of pressure chambers 1131. The common electrode is formed by a wiring pattern formed on the substrate 111 and a wiring pattern formed on the actuator 113.

[0056] The individual electrodes or the common electrodes of the actuator 113 are connected to a circuit substrate mounted with a driver IC and arranged in the cover 15. For example, the circuit substrate drives the actuator 113 by applying a driving voltage to the wiring pattern of the actuator 113 using the driver IC, and increases or decreases the volume of the pressure chamber 1131, so that droplets are ejected from the nozzle 1141.

[0057] The manifold unit 12 includes a manifold 121 and an ink supply pipe 123. The manifold unit 12 may further include a cooling water supply pipe and a cooling water discharge pipe.

[0058] The manifold 121 is formed in a plate shape or a block shape. The manifold 121 is formed by, for example, integrally assembling a plurality of components, and forms a supply path 1211 and a cooling flow path.

[0059] For example, the manifold 121 includes a supply path 1211 connected to the supply port 1111 of the substrate 111 and forming a liquid supply path and a cooling path forming a flow path for a cooling fluid. The manifold 121 includes a pair of supply paths 1211 because it is connected to a pair of head bodies 11 .

[0060] One main surface of the manifold 121 is fixed to the main surface of the substrate 111. In addition, in the manifold 121, a top plate is provided on the main surface opposite to the main surface on which the substrate 111 is fixed. Ink supply tubes 123 are fixed to the manifold 121 via the top plate.

[0061] The supply path 1211 is fluidically connected to the ink supply tube 123 and the supply port 1111 of the substrate 111. The supply path 1211 is a flow path of liquid between the ink supply tube 123 and the supply port 1111.

[0062] The ink supply tube 123 is connected to the supply path 1211. In the present embodiment, since the liquid ejection head 1 includes a pair of head main bodies 11, a pair of ink supply tubes 123 are provided.

[0063] The cover 15 includes, for example, a body that covers the side surfaces of the pair of head main bodies 11 and the outline of the manifold unit 12 , and a mask plate that covers a portion of the pair of head main bodies 11 on the nozzle plate 114 side.

[0064] In addition, the outline body exposes, for example, the ink supply tube 123 in the manifold unit 12 to the outside.

[0065] The mask plate covers the pair of head main bodies 11 except for the plurality of nozzles 1141 and the areas around the plurality of nozzles 1141 of the nozzle plate 114 .

[0066] The liquid ejection head 1 configured in this manner has, in the head body 11 , a plurality of individual electrodes capable of applying a driving voltage to each piezoelectric body 1133 , and a common electrode capable of applying a driving voltage to all the piezoelectric bodies 1133 .

[0067] Therefore, the liquid ejection head 1 can selectively drive the plurality of pressure chambers 1131 individually or in common. In addition, when the pressure chambers 1131 are driven, the pressure chambers 1131 are deformed in a shared mode, and the ink supplied into the pressure chambers 1131 is pressurized. Therefore, the liquid ejection head 1 can selectively eject the pressurized ink from the nozzles 1141 opposite to the pressure chambers 1131.

[0068] The liquid ejection head 1 cools a head main body 11 as a liquid ejection portion by means of a manifold unit 12 .

[0069] Refer to the following Figure 7 The liquid ejection device 2 having the liquid ejection head 1 is described. The liquid ejection device 2 includes a housing 2111, a medium supply unit 2112, an image forming unit 2113, a medium discharge unit 2114, a conveying device 2115 as a support device, a maintenance device 2117, and a control unit 2118. In addition, the liquid ejection device 2 includes a cooling device for adjusting the temperature of the ink supplied to the liquid ejection head 1.

[0070] The liquid ejection device 2 is an inkjet printer that performs image formation processing on paper P by ejecting liquid such as ink while transporting a recording medium such as paper P as a ejection object along a prescribed conveying path 2001 from a medium supply section 2112 through an image forming section 2113 to a medium discharge section 2114.

[0071] The medium supply unit 2112 includes a plurality of paper supply cassettes 21121. The image forming unit 2113 includes a support unit 2120 for supporting paper and a plurality of head units 2130 disposed above the support unit 2120 to face each other. The medium discharge unit 2114 includes a paper discharge tray 21141.

[0072] The support unit 2120 includes a conveyor belt 21201 provided in an annular shape in a predetermined area where image formation is performed, a support plate 21202 supporting the conveyor belt 21201 from the inside, and a plurality of belt rollers 21203 provided on the inside of the conveyor belt 21201 .

[0073] The head unit 2130 includes a plurality of liquid ejection heads 1 as inkjet heads, a plurality of supply tanks 2132 as liquid tanks respectively mounted on the liquid ejection heads 1 , a pump 2134 for supplying ink, and a connecting flow path 2135 connecting the liquid ejection heads 1 and the supply tanks 2132 .

[0074] In this embodiment, the liquid ejection heads 1 include four colors of cyan, magenta, yellow, and black and four color supply tanks 2132 for storing inks of these colors. The supply tanks 2132 are connected to the liquid ejection heads 1 via connection channels 2135 .

[0075] The pump 2134 is a liquid delivery pump composed of, for example, a piezoelectric pump. The pump 2134 is connected to the control unit 2118 and driven and controlled by the control unit 2118.

[0076] The connection flow path 2135 includes a supply flow path connected to the ink supply tube 123 of the liquid ejecting head 1 .

[0077] The conveying device 2115 conveys the paper P along the conveying path 2001 from the paper supply cassette 21121 of the medium supply unit 2112 through the image forming unit 2113 to the paper discharge tray 21141 of the medium discharge unit 2114. The conveying device 2115 includes a plurality of guide plate pairs 21211 to 21218 and a plurality of conveying rollers 21221 to 21228 arranged along the conveying path 2001. The conveying device 2115 supports the paper P so as to be relatively movable with respect to the liquid ejection head 1.

[0078] The cooling device 2116 includes a cooling water tank, a cooling circuit such as a pipe and a hose for supplying cooling water, a pump for supplying cooling water, and a cooler for adjusting the temperature of cooling water. The cooling device 2116 uses a pump to deliver water, and supplies the cooling water in the cooling water tank adjusted to a specified temperature by the cooler to the cooling flow path in the manifold through the cooling circuit, or recovers the water that passes through the cooling flow path in the manifold and is discharged. It should be noted that the cooler is, for example, a refrigeration device.

[0079] The maintenance device 2117, for example, sucks and recovers the ink remaining on the outer surface of the nozzle plate 114 during maintenance. In addition, when the liquid ejection head 1 is a non-circulating type, the maintenance device 2117 recovers the ink in the head body 11 during maintenance. Such a maintenance device 2117 has a tray, a tank, etc. for storing the recovered ink.

[0080] The control unit 2118 includes a CPU 21181 which is an example of a processor having a processing circuit, a ROM (Read Only Memory) for storing various programs, a RAM (Random Access Memory) for temporarily storing various variable data, image data, etc., and an interface unit for inputting and outputting data from the outside.

[0081] According to the liquid ejection head 1 and the liquid ejection device 2 thus constructed, the influence of water hammer can be suppressed by using the nozzle plate forming the nozzle as a pressure buffer damper. In addition, for example, in a high-productivity inkjet head with a large ink ejection amount, since it is desired to supply ink from both sides of the actuator groove 1135 that ejects ink, the ink ejection amount can be ensured by passing through the second common flow path 1162 on the side in a roundabout manner from both ends of the actuator substrate forming the actuator groove 1135 and supplying ink from both sides of the groove. At this time, in the case of a high-productivity inkjet head with a large ink supply amount that prints at high speed and drives at high speed, because the ink flow rate suddenly decreases when the DUTY decreases sharply from the high DUTY, a water hammer phenomenon (water hammer phenomenon) may occur, and the stability of the curved liquid surface required for stable printing is affected. Then, when the thickness of the nozzle plate 114 is Tmm, by setting the relationship between the distance Lmm between the supply port and the farthest actuator 113 and the ink flow path width Wmm to satisfy

[0082] L≥(-372.02T+26.0415)W′+(47.616T4.7618)W+7.1429

[0083] The dimension setting of (Formula 1) can maintain the desired discharge performance even in the pressure chamber at the farthest position.

[0084] It should be noted that the embodiments of the present invention are not limited to the above-mentioned configurations.

[0085] For example, in the above example, a configuration is illustrated in which a supply port 1111 which is a long hole is arranged between a pair of actuators 113, and a supply port is not arranged in the second common flow path 1162 on both sides, but the present invention is not limited to this. The shape, number and arrangement of the supply port 1111 can be appropriately set. For example, a supply port 1111 which is a through hole and through which liquid flows may be formed in the common flow path 1162. For example, when the supply port 1111 is arranged in the central part of the second common flow path 1162 on both sides in the first direction, the length of the maximum supply distance L becomes half, and if the interval at which the supply port 1111 is arranged is reduced, the length L of the ink flow path also becomes smaller.

[0086] For example, in the common flow path 1162 where the actuator groove 1135 farthest from the supply port is present, the position of the supply portion 117, which is the reference position of the maximum supply distance L, changes depending on the position of the supply port 1111 or the supply port 1111 not being formed. That is, the supply portion 117 that supplies the liquid to the common flow path 1162 may be the supply port 1111 formed in the common flow path 1162 or the end of the common flow path 1162 in the first direction. Therefore, the maximum supply distance L may be 1 / 2 of the distance between the plurality of supply ports 1111 arranged in the same common flow path 1162 in the first direction, or 1 / 2 of the distance from the end of the common flow path 1162 in the first direction to the supply port 1111 arranged in the same common flow path 1162. In addition, the maximum supply distance L may be 1 / 2 of the length of the common flow path 1162 in the first direction.

[0087] For example, as another embodiment, Figure 8 As shown in FIG. 1 , in addition to the supply port 1111 formed in the center of the first common flow path 1161, supply ports 1111 may also be provided in the second common flow paths 1162 on both sides. Figure 8 , Fig. 9 As shown in FIG. 1 , when the supply port 1111 and the inlet of the farthest actuator groove 1135 are arranged in the same common flow path 1162, the supply port 1111 becomes the supply portion 117. Figure 8 As shown, in the case of a flow path configuration in which the supply port 1111 is provided at the center of the common flow path 1162, L is 1 / 2 times the distance between two supply portions 117 arranged along the common flow path 1162, for example, 1 / 2 times the distance between the supply portion 117 at the end of the common flow path 1162 and the supply portion 117 at the center. For example, in the case where the supply port 1111 is located at the center of the second common flow path 1162, L becomes 1 / 2 times the case where there is no supply port 1111 in the common flow path 1162 of the actuator groove 1135 farthest from the supply port 1111 and the end of the actuator 113 in the first direction is used as a reference. In addition, when the flow path length from the supply port 1111 to the farthest actuator groove 1135 varies depending on the location, when the longest distance is set to L and the thickness of the nozzle plate 114 is set to Tmm, the relationship between the distance Lmm between the supply port 1111 or the supply portion 117 and the farthest actuator groove 1135 and the ink flow path width Wmm satisfies:

[0088] L≥(-372.02T+26.0415)W 2 +(47.616T--4.7618)W+7.1429

[0089] …(Formula 1). Even in this embodiment, the water hammer effect on the ink flow path can be suppressed. For example, as another embodiment, Fig. 9 As shown, the supply port 1111 may be provided at multiple locations in the common flow path 1162. In addition, when the distance from the supply port 1111 or the supply portion 117 as the end of the common flow path 1162 to the farthest actuator groove 1135 varies depending on the location, the longest distance is set to L. For example, in the case of Fig. 9 In the case of the flow path configuration shown in FIG. 1 , the distance from the supply ports 1111 at two locations on the common flow path 1162 to the actuator groove 1135 located at a position in between is L. Even in this embodiment, when the thickness of the nozzle plate 114 is T mm, the relationship between the distance L mm between the supply port 1111 or the supply portion 117 and the farthest actuator groove 1135 and the ink flow path width W mm satisfies:

[0090] L≥(-372.02T+26.0415)W 2 +(47.616T-4.7618)W+7.1429

[0091] …(Formula 1).

[0092] In this embodiment as well, the influence of water hammer on the ink flow path can be suppressed.

[0093] Furthermore, in the above-described embodiment, a side-shooting type inkjet head is exemplified, but the present invention is not limited thereto, and a tip-shooting type inkjet head may also be used.

[0094] For example, although the common flow path on both sides of the pressure chamber 1131 is set as the supply side and the ink flows in from both sides, it is not limited to this. As an example, the following inkjet head may be used, that is, one side of the pressure chamber 1131 is the supply side and the other side is the discharge side, and the ink flows in from one side of the pressure chamber 1131 and flows out from the other side. Alternatively, the supply side and the discharge side may be opposite, or may be configured to be switchable.

[0095] In addition, in the above example, a non-circulating type example is described for the liquid ejection head 1, but a circulating type may also be used. For example, as a configuration in which a flow path is also formed on the discharge side, the following configuration may be used, that is, a discharge port is formed at both ends of the substrate 111, for example, in the first direction, a liquid discharge path connected to the discharge port of the substrate 111 is formed in the manifold, and further, a recovery flow path connected to the liquid discharge path is provided as a connecting flow path 2135.

[0096] For example, in this embodiment, the cross section of the actuator 113 is a trapezoidal shape and the cross section of the second common flow path 1162 is also a trapezoidal shape inclined on one side, but the present invention is not limited thereto. For example, other cross-sectional shapes such as a rectangular shape may be used.

[0097] Furthermore, for example, the liquid to be discharged is not limited to ink for printing, and for example, a device that discharges a liquid containing conductive particles for forming a wiring pattern of a printed wiring board may be used.

[0098] In addition, in the above-mentioned embodiment, although an example of an inkjet head being used in a liquid ejecting device such as an inkjet printer is shown, it is not limited to this, and for example, it can also be used in a 3D printer, industrial manufacturing machinery, and medical use, and can achieve miniaturization, lightness, and low cost.

[0099] According to at least one of the embodiments described above, water hammer can be suppressed.

[0100] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the purpose of the invention. These embodiments and their variations are included in the scope and purpose of the invention, and are also included in the invention described in the claims and their equivalents.

Claims

1. A liquid ejection head, comprising: a nozzle plate having nozzles; and a liquid flow path, the liquid flow path having a plurality of actuator grooves constituting pressure chambers respectively connected to the plurality of nozzles and one or more common flow paths extending in a first direction and connected to the plurality of actuator grooves, and the liquid flow path having a supply port to which liquid is supplied, When the thickness of the nozzle plate is Tmm, the relationship between the distance in the first direction from the supply portion for supplying liquid to the common flow path to the farthest actuator groove in the common flow path, i.e., the maximum supply distance Lmm, and the dimension of the common flow path in the second direction intersecting the first direction, i.e., the flow path width Wmm, satisfies: L≥(-372.02T+26.0415)W 2 +(47.616T-4.7618)W+7.1429 …(Formula 1), The nozzle plate is formed of a flexible film and has a Young's modulus of 9.1 GPa or more.

2. The liquid ejection head according to claim 1, wherein: The liquid ejection head has one or more common flow paths, and the supply port is formed in at least any one of the common flow paths. The supply portion that supplies liquid to the common flow channel is the supply port, or an end portion of the common flow channel in the first direction.

3. The liquid ejection head according to claim 2, wherein: The maximum supply distance L is 1 / 2 of the distance in the first direction between multiple supply ports arranged in the same common flow path, or 1 / 2 of the distance from the end of the common flow path in the first direction to the supply port arranged on the same common flow path, or 1 / 2 of the length of the common flow path in the first direction.

4. The liquid ejection head according to claim 1, wherein: A plurality of the nozzles are arranged at least in the first direction, The liquid ejection head includes an actuator in which a plurality of actuator grooves are formed, and the actuator is arranged to face the nozzle plate in a third direction intersecting the first direction and the second direction. The actuator has a plurality of actuator grooves in the first direction, each of the actuator grooves extending along the second direction intersecting the first direction, The common flow paths are formed along the first direction at one end side and the other end side of the plurality of actuator grooves in the second direction.

5. The liquid ejection head according to claim 1, wherein The liquid ejection head further includes a manifold unit and a cover.

6. The liquid ejection head according to claim 5, wherein: The cover includes an outline body and a mask plate.

7. The liquid ejection head according to claim 5, wherein: The manifold unit includes a manifold and an ink supply tube.

8. The liquid ejection head according to claim 7, wherein: The manifold is formed in a plate shape or a block shape.

9. The liquid ejection head according to claim 7, wherein: The ink supply tube is fixed to the manifold via a top plate.

10. A liquid ejection device comprising: The liquid ejection head according to any one of claims 1 to 9.

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