Inkjet head and inkjet recording device

Abstract

To secure positioning accuracy of an inkjet head relative to an attachment base stably and improve heat radiation performance of the inkjet head.SOLUTION: An inkjet head includes: a head body having attached parts each of which is placed on and attached to an edge part of a through-hole of an attachment base; and a holder which is provided below the head body and integrally holds nozzle chips having nozzles for discharging an ink. The holder has positioning parts each of which may contact with a reference member provided at the attachment base so as to serve as a positioning reference. Heat conductivity of the head body is larger than heat conductivity of the holder. A heat expansion coefficient of the holder is smaller than a heat expansion coefficient of the head body.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an inkjet head and an inkjet recording apparatus. [Background technology]

[0002] Prior art inkjet heads are disclosed in, for example, Patent Documents 1 and 2. The inkjet heads described in Patent Documents 1 and 2 employ the following configuration to position the inkjet head relative to the mounting base and to release heat generated within the inkjet head to the mounting base side.

[0003] The inkjet head described in Patent Document 1 (referred to as an inkjet recording head in Patent Document 1) has a metal base plate at its bottom. The inkjet head can be positioned relative to the mounting base (referred to as a carriage in Patent Document 1) by abutting the base plate against a reference member (referred to as a positioning member in Patent Document 1) provided on the mounting base to serve as a reference for positioning. In addition, by placing the base plate on (contacting) the mounting base, heat generated within the inkjet head can be dissipated toward the mounting base.

[0004] In the inkjet head described in Patent Document 2, the inkjet head can be positioned relative to the mounting base by positioning the fixed body of the inkjet head on a reference plate fixed to the mounting base (referred to as a mounting plate in Patent Document 2). In addition, a heat sink is thermally connected to the reference plate, so that heat generated within the inkjet head can be dissipated to the mounting base. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-028844 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-150741 Summary of the Invention [Problem to be solved by the invention]

[0006] In the inkjet head described in Patent Document 1, the base plate has a positioning function for positioning the inkjet head on the mounting base and a heat dissipation function for dissipating heat generated in the inkjet head toward the mounting base. In other words, the base plate serves both as a positioning member with a positioning function and a heat dissipation member with a heat dissipation function. Therefore, if the thermal conductivity of the base plate is increased to improve the heat dissipation performance of the inkjet head, the thermal expansion coefficient of the base plate will increase, and the positioning accuracy of the inkjet head relative to the mounting base will decrease.

[0007] Furthermore, in the inkjet head described in Patent Document 2, the heat sink is not in contact with the mounting base, which means that heat generated inside the inkjet head cannot be efficiently dissipated to the mounting base, making it difficult to improve the heat dissipation performance of the inkjet head.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an inkjet head and an inkjet printing apparatus that can improve the heat dissipation of the inkjet head while stably ensuring the positioning accuracy of the inkjet head relative to the mounting base. [Means for solving the problem]

[0009] One aspect of the inkjet head according to the present invention is a head body having an attachment portion that is placed on an edge of the through hole of the attachment base and attached; a holder provided below the head body and integrally holding a nozzle tip having a nozzle for ejecting ink, the holder has a positioning portion that can come into contact with a reference member that is provided on the mounting base so as to serve as a reference for positioning, The thermal conductivity of the head body is greater than that of the holder, and the thermal expansion coefficient of the holder is smaller than that of the head body.

[0010] One aspect of the inkjet recording apparatus according to the present invention is The inkjet head is provided. [Effects of the Invention]

[0011] According to the present invention, it is possible to improve the heat dissipation of the inkjet head while stably ensuring the positioning accuracy of the inkjet head relative to the mounting base. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic front view of an inkjet recording apparatus according to this embodiment. [Figure 2] FIG. 2 is a schematic bottom view of the head unit according to this embodiment, showing a state in which a plurality of inkjet heads are attached to a carriage. [Figure 3] FIG. 3 is a schematic plan view of the inkjet head according to this embodiment, showing the inkjet head attached to the carriage. [Figure 4] FIG. 4 is a view taken along line IV-IV in FIG. [Figure 5] FIG. 5 is a view taken along line VV in FIG. [Figure 6] FIG. 6 is a schematic exploded view of the inkjet head according to this embodiment. [Figure 7] FIG. 7 is a schematic perspective view of the inkjet head according to this embodiment, as viewed from the bottom side of the inkjet head. [Figure 8A] FIG. 8A is a schematic perspective view of the holder. [Figure 8B] FIG. 8B is a schematic plan view of the holder. [Figure 9A]FIG. 9A is a schematic diagram showing another aspect of the inkjet head according to this embodiment, showing the inkjet head attached to the carriage. [Figure 9B] FIG. 9B is a schematic diagram showing another aspect of the inkjet head according to this embodiment, showing the inkjet head attached to the carriage. DETAILED DESCRIPTION OF THE INVENTION

[0013] This embodiment will be described below with reference to the drawings. In this embodiment, the transport direction refers to the transport direction in which the recording medium is transported. The downstream side refers to the downstream side in the transport direction, and the upstream side refers to the upstream side in the transport direction. In this embodiment, the X-axis direction refers to the main scanning direction, which is a direction perpendicular to the transport direction. The Y-axis direction refers to the sub-scanning direction, which is the transport direction. The Z-axis direction refers to the direction perpendicular to the X-axis direction and the Y-axis direction. The XZ plane refers to a virtual plane perpendicular to the Y-axis direction. The YZ plane refers to a virtual plane perpendicular to the X-axis direction.

[0014] The overall configuration of an inkjet recording apparatus 10 according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a schematic front view of the inkjet recording apparatus 10 according to this embodiment. Figure 2 is a schematic bottom view of a head unit 42 according to this embodiment, showing a state in which multiple inkjet heads 46 are attached to a carriage 44.

[0015] As shown in FIG. 1, the inkjet recording apparatus 10 according to this embodiment is a single-pass recording apparatus that forms a color image on the recording medium P by ejecting four color inks toward the recording medium P at appropriate timing while moving the recording medium P in the transport direction. The recording medium P can be any medium, such as plain paper, coated paper, fabric, or resin film, on whose surface the ink can be fixed. The inkjet recording apparatus 10 uses ink that changes phase between a gel state and a sol state (liquid state) depending on the temperature. For example, energy beam irradiation-type ink, such as UV ink, can be used, which is in a gel state at room temperature, changes to a sol state when heated, and solidifies when irradiated with energy beams during image formation.

[0016] The inkjet recording device 10 includes a device main body 12 that extends in the left-right direction in Fig. 1. The device main body 12 includes a center frame 14, a first side frame 16 disposed on one side of the center frame 14, and a second side frame 18 disposed on the other side of the center frame 14.

[0017] The first side frame 16 is provided with a paper feed section 20 for feeding recording media P. The paper feed section 20 has a plate-shaped paper feed tray 22 for placing the recording media P on it, and the paper feed tray 22 is provided on the first side frame 16 so as to be movable in the vertical direction. The paper feed tray 22 is configured to move up and down depending on the amount of recording media P to be placed on it, and the uppermost recording medium P is held at a predetermined height position.

[0018] The paper feed unit 20 has a transport unit 24 for transporting the recording medium P sent out from the paper feed tray 22 in the transport direction, and the transport unit 24 is provided from the first side frame 16 to the center frame 14. The transport unit 24 has a plurality of rotatable support rollers 26 and an endless belt 28 that is provided so as to be wound around the plurality of support rollers 26. The belt 28 is caused to circulate by the rotation of the plurality of support rollers 26, thereby transporting the recording medium P sent out from the paper feed tray 22 in the transport direction.

[0019] The center frame 14 is provided with an image forming unit 30 for ejecting ink onto the recording medium P to form an image. The image forming unit 30 has an image forming drum 32 that supports the recording medium P, and the image forming drum 32 is rotatably mounted on the center frame 14. With the recording medium P supported on the outer circumferential surface (conveyance surface) of the image forming drum 32, the image forming drum 32 is rotated by driving a motor (not shown) for the image forming drum, thereby transporting the recording medium P in the transport direction. The image forming drum 32 has claw portions (not shown) that press the edges of the recording medium P and an adsorption portion (not shown) that adsorbs the recording medium P.

[0020] The image forming section 30 has a transfer unit 34 for transferring the recording medium P from the transport section 24 to the image forming drum 32, and the transfer unit 34 is provided in the center frame 14 between the transport section 24 and the image forming drum 32. The transfer unit 34 has a swing arm 36 that supports one end of the recording medium P transported by the transport section 24, and a transfer drum 38 that transfers the recording medium P supported by the swing arm 36 to the image forming drum 32. One end of the recording medium P on the transport section 24 is supported by the swing arm 36 and transferred to the transfer drum 38, thereby transferring the recording medium P from the transfer drum 38 to the image forming drum 32.

[0021] The image forming unit 30 has a media heating unit 40 for heating the recording medium P carried on the image forming drum 32, and the media heating unit 40 is provided downstream of the delivery drum 38 on the center frame 14. The media heating unit 40 is disposed opposite the outer circumferential surface of the image forming drum 32. The media heating unit 40 has, for example, an infrared heater or the like, and heats the image forming drum 32 and the recording medium P so that the temperature of the recording medium P transported by the image forming drum 32 falls within a predetermined range.

[0022] As shown in FIGS. 1 and 2, the image forming section 30 has a plurality of head units 42 that form an image by ejecting ink onto a recording medium P carried on an image forming drum 32, and the plurality of head units 42 are arranged downstream of the medium heating section 40. The plurality of head units 42 correspond to four colors of ink: yellow (Y), magenta (M), cyan (C), and black (K). The plurality of head units 42 corresponding to the four colors of ink, Y, M, C, and K, are arranged at intervals from the upstream side along the transport direction. Each head unit 42 is held by a respective carriage 44 that is mounted on the center frame 14 so as to be movable in the main scanning direction. In other words, each head unit 42 is mounted on the center frame 14 so as to be movable in the main scanning direction via the respective carriage 44. Each carriage 44 is made of, for example, an aluminum alloy.

[0023] Each head unit 42 has a plurality of inkjet heads 46 that eject ink onto the recording medium P, and the plurality of inkjet heads 46 are mounted on a carriage 44 that serves as a mounting base. The plurality of inkjet heads 46 are arranged, for example, in a staggered pattern along the main scanning direction (X-axis direction). In other words, each head unit 42 constitutes a line head that includes a plurality of inkjet heads 46. Note that FIG. 2 conceptually illustrates the plurality of inkjet heads 46.

[0024] As shown in FIG. 1 , the image forming unit 30 has a fixing unit 48 for fixing ink onto the recording medium P, and the fixing unit 48 is provided downstream of the multiple head units 42 on the center frame 14. The fixing unit 48 is disposed opposite the outer circumferential surface of the image forming drum 32. The fixing unit 48 has a light-emitting unit that irradiates energy rays such as ultraviolet rays. The light-emitting unit of the fixing unit 48 imparts a predetermined energy to the ink ejected onto the recording medium P, thereby curing the ink and fixing it to the recording medium P.

[0025] The image forming unit 30 has a delivery unit 50 that transports the recording medium P irradiated with energy rays from the image forming drum 32 in the transport direction. The delivery unit 50 is provided across the center frame 14 and the second side frame 18. The delivery unit 50 has a plurality of rotatable support rollers 52, an endless belt 54 that is provided so as to be wound around the plurality of support rollers 52, and a delivery drum 56 that transfers the recording medium P from the image forming drum 32 to the belt 54. The belt 54 is caused to travel in a circular motion by the rotation of the plurality of support rollers 52, thereby transporting the recording medium P sent out from the image forming drum 32 in the transport direction.

[0026] The second side frame 18 is provided with a paper discharge section 58 for discharging the recording medium P on which an image has been formed. The paper discharge section 58 has a plate-shaped paper discharge tray 60 on which the recording medium P on which an image has been formed is placed. The paper discharge section 58 stores the recording medium P until the user removes the recording medium P from the paper discharge tray 60.

[0027] Next, a specific configuration of the inkjet head 46 according to this embodiment will be described with reference to FIGS. 3 to 8. FIG. 3 is a schematic plan view of the inkjet head 46 according to this embodiment, showing the inkjet head 46 attached to the carriage 44. FIG. 4 is a view taken along line IV-IV in FIG. 3. FIG. 5 is a view taken along line VV in FIG. 3. In FIG. 5, cross sections of the nozzle tip 70 and the manifold 74 are not shown. FIG. 6 is a schematic exploded view of the inkjet head 46 according to this embodiment. FIG. 7 is a schematic perspective view of the inkjet head 46 according to this embodiment, seen from the bottom side of the inkjet head 46. FIG. 8A is a schematic perspective view of the holder 72. FIG. 8B is a schematic plan view of the holder 72. FIGS. 9A and 9B are schematic views showing another aspect of the inkjet head 46 according to this embodiment, showing the inkjet head 46 attached to the carriage 44.

[0028] 3 to 7, the inkjet head 46 according to this embodiment is mounted on a carriage 44 serving as a mounting base, and closes a through-hole 44h formed in the carriage 44. The inkjet head 46 also includes a head body 62, which is made of, for example, an aluminum alloy. Note that FIG. 3 shows one inkjet head 46 as a representative example.

[0029] As shown in FIGS. 3 to 5, the head main body 62 has flange portions 64 as mounting portions on both sides of its upper portion in the X-axis direction (main scanning direction). Each flange portion 64 of the head main body 62 is placed on the edge of a through-hole 44h on the upper surface (mounting surface) of the carriage 44 and mounted with a mounting bolt 66. Each flange portion 64 of the head main body 62 has an insertion hole 64h for inserting the mounting bolt 66. One flange portion 64 has a first notch 64n formed therein, and each flange portion 64 has a second notch 64v formed therein. In one flange portion 64, the first notch 64n and the second notch 64v are arranged at an interval in the Y-axis direction.

[0030] Instead of having flange portions 64 on both sides of the upper part of the head body 62 in the X-axis direction, flange portions may be provided on both sides of the upper part of the head body 62 in the Y-axis direction, or rectangular frame-shaped flange portions may be provided on the outer periphery of the upper part of the head body 62.

[0031] 4 to 6, a box-shaped cover member 68 is provided on the upper side of the head main body 62. The cover member 68 is made of, for example, an aluminum alloy. The cover member 68 is also thermally connected to the head main body 62.

[0032] As shown in FIGS. 6 to 8B, a box-shaped holder 72 that integrally holds the nozzle tip 70 is provided on the lower side (lower surface) of the head main body 62. The holder 72 is arranged inside the through-hole 44h of the carriage 44. The holder 72 is made of, for example, carbon fiber reinforced resin. The holder 72 has an accommodation space 72s inside. A through-hole 72h is formed in the bottom surface of the holder 72, and the through-hole 72h communicates with the accommodation space 72s. The holder 72 is configured so as not to come into contact with the upper surface of the carriage 44.

[0033] As shown in Figures 4, 5, and 7, the nozzle tip 70 has a plurality of nozzles 70n for ejecting ink. The nozzle tip 70 is disposed inside a through-hole 72h of the holder 72. A manifold 74 extending in the X-axis direction is provided above the nozzle tip 70, and the manifold 74 is disposed in an accommodation space 72s of the holder 72. A common ink chamber (not shown) for storing ink is formed inside the manifold 74. A supply port 76 for supplying ink to the ink supply chamber is provided at one side in the X-axis direction on the top surface of the head main body 62. A discharge port 78 for discharging ink from the ink supply chamber is provided at the other side in the X-axis direction on the top surface of the head main body 62.

[0034] The nozzle tip 70 is formed with a plurality of pressure chambers (not shown) for each nozzle 70n, and each pressure chamber is connected to a common ink chamber and the corresponding nozzle 70n. Each pressure chamber is configured to be pressurized by driving a driving element (not shown), such as a piezoelectric element or a heating element. Each nozzle 70n is configured to eject (send) ink when the corresponding pressure chamber is pressurized. In addition, a wiring board 80 for supplying power to the plurality of driving elements is provided within the cover member 68. In other words, the wiring board 80 for causing the ejection operation of the plurality of nozzles 70n is provided within the cover member 68. The wiring board 80 is thermally connected to the head main body 62.

[0035] A heater 82, such as a polyimide heater, that heats the ink in the common ink chamber is provided on the outside of the manifold 74. The heater 82 is thermally connected to the head main body 62. By heating the ink in the common ink chamber with the heater 82, the viscosity of the ink in the common ink chamber can be adjusted to a viscosity that allows it to be ejected from the nozzle 70n.

[0036] 4 and 6, a holder 72 is provided below the head main body 62, and the head main body 62 and the holder 72 are joined together with an adhesive. The type of adhesive is not particularly limited, but examples include epoxy adhesives, acrylic adhesives, fluorine adhesives, rubber adhesives, urethane adhesives, and silicone adhesives.

[0037] As shown in FIGS. 8A and 8B, an endless filling groove 72g for filling with adhesive is formed in the joining surface 72f of the holder 72 so as to surround the storage space 72s. As shown in FIG. 3, each flange portion 64 is formed with a plurality of air escape holes 64b for releasing air to the outside, the air escape holes 64b communicating with the filling groove 72g of the holder 72. The air escape holes 64b of each flange portion 64 penetrate the corresponding flange portion 64. Note that instead of forming the filling groove 72g in the joining surface 72f of the holder 72, an endless filling groove (not shown) may be formed in the joining surface 62f of the head main body 62 so as to surround the storage space 72s. In this case, instead of forming the air escape holes 64b in the flange portion 64, the air escape holes (not shown) are formed in the holder 72.

[0038] 7 to 8B, a first protruding piece 84 protruding in the X direction is formed on one side in the X axis direction at the top of holder 72. Second protruding pieces 86 protruding in the X axis direction are formed on both sides in the X axis direction at the top of holder 72. The first protruding piece 84 and one of the second protruding pieces 86 are arranged with a gap in the Y axis direction.

[0039] 3, 4, and 6 to 8B, a first positioning portion 88 for positioning the inkjet head 46 (holder 72) in the X-axis direction (main scanning direction) is provided at the tip of the first protruding piece 84. In other words, the holder 72 has the first positioning portion 88 integrally formed on one side of its upper portion in the X-axis direction. The first positioning portion 88 can come into contact with a pin-shaped first reference member 90 provided on the top surface of the carriage 44 as a reference for positioning the inkjet head 46 in the X-axis direction.

[0040] 3, 8A, and 8B, the first positioning portion 88 has a first contact surface 88f that can contact the first reference member 90, and the first contact surface 88f is parallel to the YZ plane. The first positioning portion 88 is disposed closer to the carriage 44 than the center position of the flange portion 64 in the thickness direction. The first contact surface 88f of the first positioning portion 88 is disposed inside the first cutout portion 64n of the flange portion 64 in a plan view. The position of the first contact surface 88f of the first positioning portion 88 is adjusted in the X-axis direction with respect to the nozzle tip 70 (nozzle 70n).

[0041] 3, 4, and 6 to 8B, a second positioning portion 92 for positioning the inkjet head 46 (holder 72) in the Y-axis direction (sub-scanning direction) is provided on the tip side of each second protruding piece 86. In other words, the holder 72 has a second positioning portion 92 integrally formed on both sides of its upper portion in the X-axis direction. The second positioning portions 92 can come into contact with a pin-shaped second reference member 94 provided on the top surface of the carriage 44 as a reference for positioning the inkjet head 46 in the Y-axis direction.

[0042] 3, 8A, and 8B, each second positioning portion 92 has a second contact surface 92f that can contact the second reference member 94, and each second contact surface 92f is parallel to the XZ plane. Each second positioning portion 92 is disposed closer to the carriage 44 than the center position of the flange portion 64 in the thickness direction. In plan view, the second contact surface 92f of each second positioning portion 92 is disposed inside the second cutout portion 64v of the flange portion 64. The position of the second contact surface 92f of each second positioning portion 92 is adjusted in the Y-axis direction with respect to the nozzle tip 70 (nozzle 70n).

[0043] As described above, the holder 72 has one first positioning portion 88 and two second positioning portions 92. The holder 72 may have two or more first positioning portions 88. The holder 72 may have three or more second positioning portions 92. When the holder 72 has two or more first positioning portions 88, the number of second positioning portions 92 may be one.

[0044] The first positioning portion 88 is brought into contact with the first reference member 90, and the second positioning portion 92 is brought into contact with the second reference member 94. This allows the inkjet head 46 to be positioned relative to the carriage 44 so that the nozzle tip 70 is located at a predetermined position in the X-axis direction and the Y-axis direction.

[0045] 4, the holder 72 may be configured to be in contact with the upper surface of the carriage 44, as shown in Figures 9A and 9B. Also, as shown in Figure 9B, a sheet-like elastic body 96 made of rubber or the like may be interposed between the joint surface 62f of the head main body 62 and the joint surface 72f of the holder 72.

[0046] Next, the physical properties of the head main body 62 and the holder 72 will be described with reference to FIGS.

[0047] 4 and 6, the thermal conductivity of the head main body 62 is greater than that of the holder 72. The thermal conductivity of the head main body 62 is smaller than that of the carriage 44.

[0048] The thermal expansion coefficient of the holder 72 is smaller than that of the head body 62. Specifically, in a temperature environment of 20° C. or higher and 100° C. or lower, the thermal expansion coefficient of the head body 62 is 18×10 -6 The thermal expansion coefficient of the holder 72 is 18×10 -6 The longitudinal elastic modulus of the adhesive (adhesive layer of the adhesive) after the head body 62 and the holder 72 are joined is less than 70.6 KN / mm 2 The following is the result.

[0049] According to the configuration of the inkjet head 46 of this embodiment, the flange portions 64 of the head body 62 are mounted on the edges of the through-holes 44h on the upper surface of the carriage 44 and are thermally connected to the carriage 44. The thermal conductivity of the head body 62 is greater than that of the holder 72. Therefore, heat generated within the inkjet head 46, such as heat generated from the wiring board 80 or the heater 82, can be efficiently dissipated to the carriage 44 side via the head body 62, thereby improving the heat dissipation performance of the inkjet head 46.

[0050] As described above, the thermal expansion coefficient of the holder 72 is smaller than that of the head main body 62. Therefore, it is possible to reduce the amount of displacement of the first positioning portion 88 and the second positioning portion 92 due to changes in environmental temperature. Furthermore, the holder 72 integrally holds the nozzle chip 70 having the nozzle 70n. Therefore, it is possible to suppress misalignment of the nozzle chip 70 (nozzle 70n) relative to the first positioning portion 88 and the second positioning portion 92. This makes it possible to stably ensure the positioning accuracy of the inkjet head 46 relative to the carriage 44.

[0051] That is, according to this embodiment, the positioning accuracy of the inkjet head 46 relative to the carriage 44 can be stably ensured, while the heat dissipation performance of the inkjet head 46 can be improved.

[0052] Furthermore, according to the configuration of the inkjet head 46 of this embodiment, the thermal conductivity of the head main body 62 is smaller than that of the carriage 44. In other words, the thermal conductivity of the carriage 44 is greater than that of the head main body 62. Therefore, according to this embodiment, heat generated within the inkjet head 46 can be dissipated more efficiently to the carriage 44 side, thereby further improving the heat dissipation performance of the inkjet head 46.

[0053] Furthermore, according to the configuration of the inkjet head 46 of this embodiment, the wiring board 80 is thermally connected to the head body 62. Therefore, according to this embodiment, heat generated from the wiring board 80 can be efficiently dissipated to the carriage 44 side via the head body 62.

[0054] Furthermore, according to the configuration of the inkjet head 46 of this embodiment, the heater 82 is thermally connected to the head main body 62. Therefore, according to this embodiment, heat generated from the heater 82 can be efficiently dissipated to the carriage 44 side via the head main body 62.

[0055] Furthermore, according to the configuration of the inkjet head 46 of this embodiment, the head main body 62 and the holder 72 are bonded together with an adhesive. Therefore, the gap between the bonding surface 62f of the head main body 62 and the bonding surface 72f of the holder 72 can be sealed with the adhesive (an adhesive layer). Therefore, according to this embodiment, it is possible to prevent ink from entering the inkjet head 46 from between the bonding surface 62f of the head main body 62 and the bonding surface 72f of the holder 72.

[0056] Furthermore, according to the configuration of the inkjet head 46 of this embodiment, a filling groove 72g is formed on the joining surface 72f of the holder 72 so as to surround the accommodation space 72s. Therefore, with the filling groove 72g filled with adhesive, the head main body 62 and the holder 72 can be easily joined by butting the joining surface 62f of the head main body 62 against the joining surface 72f of the holder 72. In particular, if the head main body 62 has an air escape hole 64b formed in communication with the filling groove 72g of the holder 72, the head main body 62 and the holder 72 can be joined even more easily. Therefore, according to this embodiment, the assembly of the inkjet head 46 can be improved.

[0057] Furthermore, according to the configuration of the inkjet head 46 according to this embodiment, the longitudinal elastic modulus of the adhesive after the head body 62 and the holder 72 are joined is 70.6 KN / mm 2 Therefore, according to this embodiment, distortion of the head main body 62 and the holder 72 due to the difference in thermal expansion between the head main body 62 and the holder 72 can be absorbed by the adhesive layer of the adhesive.

[0058] Furthermore, according to the configuration of the inkjet head 46 of this embodiment, the first positioning portion 88 and each second positioning portion 92 are disposed closer to the carriage 44 than the center position in the thickness direction of the flange portion 64. Therefore, according to this embodiment, the heights of the first reference member 90 and the second reference member 94 can be reduced, thereby improving the usability of the inkjet recording apparatus 10.

[0059] Furthermore, according to the configuration of the inkjet head 46 of this embodiment, the first contact surface 88f of the first positioning portion 88 is disposed, in plan view, inside the first cutout portion 64n of the flange portion 64. The second contact surface 92f of each second positioning portion 92 is disposed, in plan view, inside the second cutout portion 64v of the flange portion 64. Therefore, according to this embodiment, even if the user accidentally collides the inkjet head 46 with an obstacle, deformation of the first positioning portion 88 and the second positioning portion 92 can be suppressed.

[0060] Furthermore, according to the configuration of the inkjet head 46 of this embodiment, the holder 72 is configured so as not to come into contact with the upper surface of the carriage 44. Therefore, according to this embodiment, it is possible to prevent the holder 72 from being distorted due to thermal expansion of the head main body 62.

[0061] Furthermore, according to the configuration of the inkjet head 46 of this embodiment, the elastic body 96 is interposed between the joint surface 62f of the head main body 62 and the joint surface 72f of the holder 72. Therefore, according to this embodiment, the elastic body 96 can absorb distortion of the head main body 62 and the holder 72 caused by the difference in thermal expansion between the head main body 62 and the holder 72.

[0062] Although the present embodiment has been specifically described above, the present invention is not limited to the specific embodiment described above. Various modifications and changes to the specific examples described in the above embodiment are possible within the scope of the gist of the present invention as defined in the claims. [Industrial Applicability]

[0063] The present invention is useful as an inkjet head and an inkjet recording apparatus that can improve the heat dissipation of the inkjet head while stably ensuring the positioning accuracy of the inkjet head relative to the mounting base. [Explanation of symbols]

[0064] 10. Inkjet recording device 12 Device body 14 Center Frame 16 First side frame 18 Second side frame 20 Paper feed section 22 Paper tray 24 Conveyor 26 Support roller 28 Belt 30 Image forming unit 32 Image forming drum 34 Delivery Unit 36 Swingarm 38 Transfer drum 40 Medium heating section 42 Head Unit 44 Carriage (mounting base) 44h through hole 46 Inkjet head 48 Fixing section 50 Delivery Department 52 Support roller 54 Belt 56 Transfer drum 58 Paper output section 60 Output tray 62 Head body 62f joint surface 64 Flange 64h insertion hole 64b Air escape hole 64n First notch 64v Second notch 66 Mounting bolt 68 Cover member 70 nozzle tip 70n nozzle 72 Holder 72f joint surface 72g filling groove 72h through hole 72s Storage Space 74 Manifold 76 Supply Port 78 Exhaust port 80 Wiring board 82 Heater 84 1st protruding piece 86 Second protruding piece 88 First positioning part (positioning part) 88f 1st contact surface 90 First reference member (reference member) 92 Second positioning part (positioning part) 92f 2nd contact surface 94 Second reference member (reference member) 96 Elastic Body

Claims

1. a head body having an attachment portion that is placed on an edge of the through hole of the attachment base and attached; a holder provided below the head body and integrally holding a nozzle tip having a nozzle for ejecting ink, the holder has a positioning portion that can come into contact with a reference member that is provided on the mounting base so as to serve as a reference for positioning, The thermal conductivity of the head body is greater than the thermal conductivity of the holder, and the thermal expansion coefficient of the holder is smaller than the thermal expansion coefficient of the head body. Inkjet head.

2. The holder has the positioning portion integrally therewith.

2. The ink jet head according to claim 1.

3. The positioning unit is a first positioning portion that can come into contact with a first reference member that is provided on the mounting base so as to serve as a reference for positioning in the main scanning direction; a second positioning portion that can come into contact with a second reference member that is provided on the mounting base so as to serve as a reference for positioning in the sub-scanning direction; 2. The ink jet head according to claim 1.

4. The head body and the holder are joined together with an adhesive.

2. The ink jet head according to claim 1.

5. The holder has an accommodation space therein, a filling groove for filling an adhesive is formed on a joining surface of one of the head body and the holder so as to surround the accommodation space; 5. The ink jet head according to claim 4.

6. an air escape hole for releasing air to the outside formed in the other of the head body and the holder and communicating with the filling groove; 6. The ink jet head according to claim 5.

7. The longitudinal elastic modulus of the adhesive after joining the head body and the holder is 70.6 KN / mm ２ Below is the 5. The ink jet head according to claim 4.

8. the positioning portion is disposed closer to the mounting base than the center position of the mounting portion in the thickness direction.

2. The ink jet head according to claim 1.

9. one of the first positioning portion and the second positioning portion is two or more, and the other of the first positioning portion and the second positioning portion is one or more; 4. The ink jet head according to claim 3.

10. a notch is formed in the holder, and the positioning portion is disposed inside the notch in a plan view; 2. The ink jet head according to claim 1.

11. The holder is configured to be in no contact with the mounting base.

2. The ink jet head according to claim 1.

12. The holder is configured to contact the mounting base.

2. The ink jet head according to claim 1.

13. The head further includes an elastic body interposed between the head body and the holder. The ink jet head according to claim 12.

14. In a temperature environment of 20°C or higher and 100°C or lower, the thermal expansion coefficient of the head body is 18×10 －６ The thermal expansion coefficient of the holder is 18×10 －６ is less than 2. The ink jet head according to claim 1.

15. The holder is made of resin.

2. The ink jet head according to claim 1.

16. further comprising a heater for heating the ink; 2. The ink jet head according to claim 1.

17. The heater is thermally connected to the head body.

17. The ink jet head according to claim 16.

18. a position of the first positioning portion in a main scanning direction is adjusted with respect to the nozzle tip, and a position of the second positioning portion in a sub-scanning direction is adjusted with respect to the nozzle tip; 4. The ink jet head according to claim 3.

19. The thermal conductivity of the head body is lower than the thermal conductivity of the mounting base.

2. The ink jet head according to claim 1.

20. a box-shaped cover member provided on the upper side of the head main body; a wiring board provided inside the cover member for causing the nozzles to perform a discharge operation, 2. The ink jet head according to claim 1.

21. An ink jet head comprising: an ink jet head according to any one of claims 1 to 20; Inkjet recording device.

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