JP2020093487A - Inkjet head and inkjet recording device - Google Patents

Abstract

To provide an inkjet head and an inkjet recording device, which can record a high-quality image.SOLUTION: An inkjet head comprises a flow path main body, a vibration plate, a first piezoelectric element and a second piezoelectric element of laminate types, a first adhesion layer, a second adhesion layer, and a restraint tool. The flow path main body includes a first nozzle and a second nozzle, and further includes an inner flow path therein. The inner flow path includes a first branch flow path through which ink flows to the first nozzle and a second branch flow path through which ink flows to the second nozzle. Heights of surfaces at a second side in a height direction of the first piezoelectric element and the second piezoelectric element are set to be equal, in a state where the first piezoelectric element is provided at a first part through the first adhesion layer and the second piezoelectric element is provided at a second part through the second adhesion layer. The first part is a part of the vibration plate, a part of a wall face of the first branch flow path, and the second part is a part of the vibration plate, a part of a wall face of the second branch flow path.SELECTED DRAWING: Figure 3

Description

The present invention relates to an inkjet head and an inkjet recording device.

Technologies related to an inkjet head of an inkjet recording apparatus have been proposed. For example, Patent Document 1 discloses an inkjet head. In the inkjet head, the vibration plate is bonded to the piezoelectric element via the leg portion with an adhesive. In the diaphragm, the following first and second surfaces are provided with a film treated so as not to get wet with the adhesive. The film is a water repellent layer that has been subjected to a water repellent treatment. The first surface is an exposed surface other than the mounting position of the leg portion on the piezoelectric element side. The second side is the side of the leg.

JP 2001-121694A

In the inkjet head, a plurality of nozzles are provided on the first side in the height direction, and a plurality of piezoelectric elements are provided on the surface of the vibration plate on the second side in the height direction in association with each nozzle. The piezoelectric element is deformed in the height direction according to the application of the drive signal. Further, the inkjet head is provided with a restraint on the second side in the height direction of the piezoelectric element. The restraint restrains the deformation of the piezoelectric element toward the second side in the height direction when the piezoelectric element deforms in the height direction in response to the application of the drive signal. That is, the piezoelectric element deforms to the first side in the height direction according to the application of the drive signal, and deforms the diaphragm to the first side in the height direction. In the inkjet head, ink is ejected from the nozzles corresponding to the deformed piezoelectric element due to this deformation. In an inkjet recording device, an image is recorded on a recording medium with ink ejected from a plurality of nozzles of an inkjet head. The inventor studied an inkjet head capable of recording a high quality image on a recording medium.

An object of the present invention is to provide an inkjet head and an inkjet recording device that can record high quality images.

One aspect of the present invention includes a first nozzle and a second nozzle for ejecting ink on a surface on a first side in a height direction, and a first tributary channel and a first nozzle for internally flowing the ink to the first nozzle. A flow path main body including an internal flow path including a second tributary flow path for flowing the ink to the two nozzles, and a wall surface of the first tributary flow path provided on the second side in the height direction of the flow path main body. And a diaphragm including a second portion that is a part of the wall surface of the second tributary flow path, and a drive provided as a pulse signal provided on the surface of the first portion on the second side in the height direction. Provided on a laminated first piezoelectric element that deforms in the height direction according to the application of a signal and ejects ink from the first nozzle, and a surface of the second portion on the second side in the height direction. A second laminated piezoelectric element that deforms in the height direction in response to the application of the drive signal and ejects ink from the second nozzle; and a resin layer in which an adhesive is hardened, and A first adhesive layer for adhering a part to the first piezoelectric element, a resin layer obtained by curing the same adhesive as the first adhesive layer, and adhering the second part to the second piezoelectric element; Two adhesive layers, provided on the second side in the height direction of the first piezoelectric element and the second piezoelectric element, to the second side in the height direction of the first piezoelectric element and the second piezoelectric element A restraint for restraining deformation of the first piezoelectric element and the second piezoelectric element, wherein the first piezoelectric element is provided in the first portion via the first adhesive layer and the second adhesive is provided. In the inkjet head, the height of each surface on the second side in the height direction is set to be equal in a state where the second piezoelectric element is provided in the second portion via a layer.

According to this ink jet head, the contact state with the restraint tool can be made constant by the first piezoelectric element and the second piezoelectric element. Ink ejection can be stabilized by the first nozzle and the second nozzle.

In the inkjet head, the restraint may be made of metal or ceramics. According to this configuration, the hardness of the restraint can be increased and the restraint with high rigidity can be obtained. The first piezoelectric element and the second piezoelectric element can be constrained from the second side in the height direction, and the first piezoelectric element and the second piezoelectric element can be deformed to the first side in the height direction.

In the inkjet head, the first piezoelectric element includes, on the second side in the height direction, a first spacer that adjusts the height of the surface of the first piezoelectric element on the second side in the height direction. You can In this case, the second piezoelectric element includes, on the second side in the height direction, a second spacer that adjusts the height of the surface of the second piezoelectric element on the second side in the height direction, The two spacers may be made of the same material as the first spacer.

According to each of the above-described configurations, the first spacers or the first spacers and the second spacers can equalize the heights of the respective surfaces on the second side in the height direction of the first piezoelectric element and the second piezoelectric element. it can. The first piezoelectric element and the second piezoelectric element can equalize the contact state of each surface on the second side in the height direction with respect to the restraint.

In the inkjet head, the first spacer may be a resin layer obtained by curing an electrically insulating adhesive. According to this structure, it is possible to prevent conduction through the first spacer. When the second piezoelectric element includes the second spacer, conduction through the second spacer can be prevented.

In the inkjet head, the first spacer may be a resin layer obtained by curing an adhesive having a property of being softened by a specific solvent. According to this structure, the first spacer can be removed. When the second piezoelectric element includes the second spacer, the second spacer can be removed.

In the inkjet head, the first spacer may be a resin layer obtained by curing a thermosetting adhesive. According to this configuration, the adhesive can be hardened by heating to form the first spacer. When the second piezoelectric element includes the second spacer, the adhesive can be hardened by heating to form the second spacer.

In the inkjet head, the first spacer may be a resin layer obtained by curing the same adhesive as the first adhesive layer. According to this configuration, the first spacer, the first adhesive layer, and the second adhesive layer can match various characteristics such as mechanical characteristics and chemical characteristics. That is, when the first spacer is a resin layer obtained by curing an electrically insulating adhesive, the conduction through the first spacer, the conduction through the first adhesive layer, and the conduction through the second adhesive layer are prevented. be able to. Moreover, when the first spacer is a resin layer obtained by curing an adhesive having a property of being softened by a specific solvent, the first spacer, the first adhesive layer and the second adhesive layer can be removed. Furthermore, when the first spacer is a resin layer obtained by curing a thermosetting adhesive, the adhesive can be cured by heating to form the first spacer, the first adhesive layer, and the second adhesive layer. When the second piezoelectric element includes the second spacer, the first spacer, the second spacer, the first adhesive layer, and the second adhesive layer can match various characteristics such as mechanical characteristics and chemical characteristics. However, other explanations regarding this point are the same as the case of the first spacer, the first adhesive layer, and the second adhesive layer described above, and therefore will be omitted.

In the inkjet head, the first spacer may be a metal sheet. According to this configuration, the hardness of the first spacer can be increased, and the first spacer having high rigidity in the height direction can be obtained. It is possible to suppress the first spacer from being deformed (elastically deformed) in the height direction when the first piezoelectric element is deformed in response to the application of the drive signal. It is possible to suppress absorption of the force due to the deformation of the first piezoelectric element by the first spacer. The force associated with the deformation of the first piezoelectric element can be applied to the first portion via the first adhesive layer. When the second piezoelectric element includes the second spacer, the hardness of the second spacer can be increased, and the second spacer having high rigidity in the height direction can be obtained. It is possible to suppress the second spacer from being deformed (elastically deformed) in the height direction when the second piezoelectric element is deformed in response to the application of the drive signal. It is possible to suppress absorption of the force due to the deformation of the second piezoelectric element by the second spacer. The force associated with the deformation of the second piezoelectric element can be applied to the second portion via the second adhesive layer. Metal sheets are widely understood. That is, the metal sheet includes a metal foil as well as a metal sheet material.

In the inkjet head, the first adhesive layer may be a resin layer having a durometer hardness of D70 or more. With this configuration, it is possible to prevent the force associated with the deformation of the first piezoelectric element from being absorbed by the first adhesive layer. The force associated with the deformation of the first piezoelectric element can be applied to the first portion via the first adhesive layer. It is possible to suppress absorption of the force due to the deformation of the second piezoelectric element by the second adhesive layer. The force associated with the deformation of the second piezoelectric element can be applied to the second portion via the second adhesive layer. When the first spacer is a resin layer obtained by curing the same adhesive as the first adhesive layer, it is possible to prevent the force due to the deformation of the first piezoelectric element from being absorbed by the first spacer. The force associated with the deformation of the first piezoelectric element can be applied to the first portion via the first adhesive layer. When the first spacer is a resin layer obtained by curing the same adhesive as the first adhesive layer and the second piezoelectric element includes the second spacer, the force due to the deformation of the second piezoelectric element is absorbed by the second spacer. Can be suppressed. The force associated with the deformation of the second piezoelectric element can be applied to the second portion via the second adhesive layer.

Another aspect of the present invention is an inkjet recording apparatus including any of the inkjet heads described above and a head drive unit that generates the drive signal. According to this inkjet recording device, an inkjet recording device having the above-described functions can be provided.

According to the present invention, it is possible to obtain an inkjet head and an inkjet recording device that can record a high-quality image.

It is a perspective view showing an example of a schematic structure of an ink jet recording device. FIG. 3 is a plan view showing an example of a schematic configuration of an inkjet head. A part of the signal line is shown. It is a sectional view showing an example of a schematic structure of an inkjet head. The cutting position corresponds to the line JJ shown in FIG. Illustration of signal lines connecting the head drive unit and the piezoelectric elements is omitted. It is a sectional view showing an example of a schematic structure of an inkjet head. The cutting position corresponds to the KK line shown in FIG. A part of the signal line is shown. The first state is a state in which the piezoelectric element and the diaphragm are not deformed. The second state is a state in which the piezoelectric element and the vibration plate are deformed to the first side in the height direction. It is a perspective view showing an example of schematic composition of a piezoelectric element, an adhesion layer, a part of diaphragm, and a pressure chamber. A part of the signal line is shown and a state where two signal lines are connected to the piezoelectric element is shown. 3 shows a piezoelectric element including a spacer. The illustrated range is a part of the inkjet head and corresponds to the piezoelectric element provided on the fifth side in the sub-scanning direction among the four piezoelectric elements shown in FIGS. FIG. 3 is a partial perspective view showing an example of a schematic configuration of an inkjet head. 6 shows a state in which the piezoelectric element, the adhesive layer, a part of the vibration plate, and the pressure chamber shown in FIG. 5 are assembled. A part of the signal line is shown and a state where two signal lines are connected to the piezoelectric element is shown. The illustrated range corresponds to FIG. It is a top view which shows the other example of schematic structure of an inkjet head. A part of the signal line is shown.

Embodiments for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to the configurations described below, and various configurations can be adopted within the same technical idea. For example, some of the configurations shown below may be omitted or replaced with other configurations. Other configurations may be included. Each drawing of the embodiment schematically shows a predetermined configuration. Therefore, in each drawing of the embodiment, the correspondence with other drawings or the numerical values described later that specify the configuration in the drawings may not be accurate. In each of the drawings of the embodiments, a broken line is a hide-and-seek line, a one-dot chain line is a cutting line, and a two-dot chain line is an imaginary line. Further, in each of the drawings of the embodiments, hatching indicates a cut surface.

<Inkjet recording device>
The inkjet recording device 10 will be described with reference to FIGS. In the inkjet recording apparatus 10, various recording media 15 are conveyed and an image is recorded on the recording media 15 (see FIG. 1). As the recording medium 15, a cloth or a building material is exemplified. In the embodiment, the recording medium 15 is long. However, the recording medium may be short. The ink used for recording the image is, for example, four colors of black, magenta, yellow and cyan. However, an ink of a color different from each of these color inks may be used. The number of ink colors may be 3 or less or 5 or more.

The inkjet recording apparatus 10 includes a carrier 20, inkjet heads 30K, 30M, 30Y, 30C, a carriage 70, a moving machine 75, main tanks 80K, 80M, 80Y, 80C, and supply channels 81K, 81M, 81Y. , 81C, sub-tanks 82K, 82M, 82Y, 82C, connection channels 83K, 83M, 83Y, 83C, and a controller 90 (see FIG. 1).

The carrier 20 carries the recording medium 15. In the inkjet recording apparatus 10, the conveyance of the recording medium 15 by the conveyance device 20 is performed intermittently. The carrier 20 is a belt conveyor. The carrier 20 is the same as the carrier of a known inkjet recording apparatus. Therefore, the other description of the carrier 20 will be omitted.

In the embodiment, the direction in which the transport device 20 transports the recording medium 15 is referred to as the “transport direction”. The direction orthogonal to the carrying direction is called the "main scanning direction", and the direction along the carrying direction is called the "sub scanning direction". In this case, the main scanning direction is also orthogonal to the sub scanning direction. The carrying direction, the main scanning direction, and the sub-scanning direction are horizontal. One side in the main scanning direction is called "third side", and the other side in the main scanning direction is called "fourth side". One side in the sub-scanning direction is called "fifth side", and the other side in the sub-scanning direction is called "sixth side". The fifth side in the sub-scanning direction is the upstream side in the transport direction, and the sixth side in the sub-scanning direction is the downstream side in the transport direction. Further, a direction orthogonal to the main scanning direction and the sub scanning direction is referred to as "height direction". The height direction is the vertical direction. One side in the height direction is called "first side", and the other side in the height direction is called "second side". The first side in the height direction is the lower side in the vertical direction, and the second side in the height direction is the upper side in the vertical direction.

The inkjet heads 30K, 30M, 30Y, 30C have the same configuration. The inkjet head 30K ejects black ink. The inkjet head 30M ejects magenta ink. The inkjet head 30Y ejects yellow ink. The inkjet head 30C ejects cyan ink. The inkjet heads 30K, 30M, 30Y, and 30C can record a full-color image on the recording medium 15. In FIG. 1, the pattern attached to the portion of the recording medium 15 illustrated on the downstream side of the inkjet heads 30K, 30M, 30Y, and 30C in the transport direction corresponds to the image recorded on the recording medium 15.

In the embodiment, the inkjet heads 30K, 30M, 30Y, and 30C are referred to as "inkjet head 30" when they are not distinguished from each other or when they are collectively referred to. The surface of the inkjet head 30 on the first side in the height direction is referred to as a “first end surface 32 ”. In the inkjet head 30, a plurality of nozzles 31 are formed on the first end surface 32 (see FIGS. 2 and 3). In the inkjet head 30, the plurality of nozzles 31 are arranged in the sub-scanning direction. In the inkjet head 30, each color ink is ejected from a plurality of nozzles 31. Other description of the inkjet head 30 will be given later. In FIG. 1, the illustration of the inkjet heads 30K, 30M, 30Y, and 30C is simplified.

The inkjet heads 30K, 30M, 30Y, and 30C are mounted on the carriage 70. On the carriage 70, the inkjet heads 30K, 30M, 30Y, 30C are adjacent to each other in the main scanning direction. The arrangement order of the inkjet heads 30K, 30M, 30Y, and 30C in the main scanning direction may be different from that in FIG. The arrangement order of these is appropriately determined in consideration of various conditions.

The moving machine 75 reciprocates the carriage 70 in the main scanning direction. The mobile device 75 includes two pulleys 76 and 77, a timing belt 78, and a motor 79. The pulley 76 is provided on the third side in the main scanning direction with respect to the transport device 20. The pulley 77 is provided on the fourth side in the main scanning direction with respect to the transport device 20. The pulley 77 is rotatably supported. The timing belt 78 is stretched over the pulleys 76 and 77 while tension is applied. The motor 79 is connected to the pulley 76. As the motor 79, for example, a servomotor with an encoder is adopted. The motor 79 rotates the pulley 76. In FIG. 1, the arrow inside the pulley 76 indicates the rotation direction of the pulley 76. The carriage 70 is attached to the timing belt 78 via a stay 71.

The main tank 80K stores black ink. The supply channel 81K connects the main tank 80K and the sub tank 82K. The sub tank 82K is provided on the carriage 70 on the second side in the height direction of the inkjet head 30K. The sub-tank 82K secondarily stores the black ink supplied to the inkjet head 30K. The connection channel 83K connects the sub tank 82K and the inkjet head 30K. The black ink stored in the main tank 80K flows out from the main tank 80K, flows through the supply passage 81K, and is supplied to the sub tank 82K. After that, the black ink flows through the connection channel 83K and is supplied to the inkjet head 30K.

The main tank 80M stores magenta ink. The supply channel 81M connects the main tank 80M and the sub tank 82M. The sub tank 82M is provided on the carriage 70 on the second side in the height direction of the inkjet head 30M. The sub-tank 82M secondarily stores the magenta ink supplied to the inkjet head 30M. The connection channel 83M connects the sub tank 82M and the inkjet head 30M. The magenta ink stored in the main tank 80M flows out from the main tank 80M, flows through the supply passage 81M, and is supplied to the sub tank 82M. Then, the magenta ink flows through the connection channel 83M and is supplied to the inkjet head 30M.

The main tank 80Y stores yellow ink. The supply channel 81Y connects the main tank 80Y and the sub tank 82Y. The sub tank 82Y is provided on the carriage 70 on the second side in the height direction of the inkjet head 30Y. The sub tank 82Y secondarily stores the yellow ink supplied to the inkjet head 30Y. The connection channel 83Y connects the sub tank 82Y and the inkjet head 30Y. The yellow ink stored in the main tank 80Y flows out from the main tank 80Y, flows through the supply passage 81Y, and is supplied to the sub tank 82Y. After that, the yellow ink flows through the connection channel 83Y and is supplied to the inkjet head 30Y.

The main tank 80C stores cyan ink. The supply channel 81C connects the main tank 80C and the sub tank 82C. The sub tank 82C is provided on the carriage 70 on the second side in the height direction of the inkjet head 30C. The sub-tank 82C secondarily stores the cyan ink supplied to the inkjet head 30C. The connection channel 83C connects the sub tank 82C and the inkjet head 30C. The cyan ink stored in the main tank 80C flows out from the main tank 80C, flows through the supply passage 81C, and is supplied to the sub tank 82C. After that, the cyan ink flows through the connection channel 83C and is supplied to the inkjet head 30C. In FIG. 1, the supply channels 81K, 81M, 81Y, 81C are simplified. The supply channels 81K, 81M, 81Y, and 81C are provided in a state capable of coping with the movement of the carriage 70 in the main scanning direction by the moving machine 75.

The control device 90 includes a controller 91, a head drive unit 92, and a switch unit 93. In FIG. 1, the controller 91, the head drive unit 92, and the switch unit 93 are illustrated as a unitized state as a control device 90. However, these respective units of the control device 90 may not be provided in a single housing such as a control box. For example, the switch unit 93 may be provided at positions close to the inkjet heads 30K, 30M, 30Y, 30C for the inkjet heads 30K, 30M, 30Y, 30C, respectively.

The controller 91 controls various operations executed by the inkjet recording apparatus 10. The controller 91 includes, for example, a processor, a storage, and a memory. The head drive unit 92 is a head drive circuit electrically connected to the plurality of piezoelectric elements 50. The head drive unit 92 outputs a drive signal at a predetermined cycle. The drive signal output from the head drive unit 92 is applied to a predetermined piezoelectric element 50 among the plurality of piezoelectric elements 50. The drive signal is a pulse signal having a predetermined voltage value. The switch unit 93 is a switch circuit electrically connected to each of the plurality of piezoelectric elements 50. The switch unit 93 includes switches corresponding to some or all of the plurality of piezoelectric elements 50. For example, assume that one inkjet head 30 is provided with four piezoelectric elements 50. When two switches are included in one switch unit 93, two switch units 93 are provided for one inkjet head 30. When the number of switches included in one switch unit 93 is four, one switch unit 93 is provided for each inkjet head 30. The piezoelectric element 50 will be described later.

When an image is recorded on the recording medium 15 by the inkjet recording device 10, the mobile device 75 and the transport device 20 operate as follows. In the mobile device 75, the motor 79 reciprocates and rotates clockwise and counterclockwise. With the rotation of the motor 79, the pulley 76 reciprocates and rotates on both left and right sides. When the pulley 79 rotates counterclockwise as the motor 79 rotates in a predetermined direction, the timing belt 78 also rotates counterclockwise. The pulley 77 rotates following the timing belt 78 that rotates counterclockwise. Along with this, the carriage 70 moves from the fourth side to the third side in the main scanning direction. When the carriage 70 reaches the moving end on the third side in the main scanning direction, the rotation direction of the motor 79 is reversed, and the pulley 76 rotates right. When the pulley 76 rotates to the right, the timing belt 78 also rotates to the right. The pulley 77 rotates following the timing belt 78 that rotates clockwise. Along with this, the carriage 70 moves from the third side to the fourth side in the main scanning direction. When the carriage 70 reaches the moving end on the fourth side in the main scanning direction, the rotation direction of the motor 79 is reversed again, and the pulley 76 rotates left again.

The carrier 20 moves the recording medium 15 in correspondence with the movement of the carriage 70 from the fourth side to the third side in the main scanning direction and the movement of the carriage 70 from the third side to the fourth side in the main scanning direction. Transport in the transport direction. That is, the conveyance of the recording medium 15 by the conveyance device 20 is intermittently performed according to the arrival of each of the moving ends of the carriage 70 in the main scanning direction. The ink of each color is ejected toward the recording medium 15 from each nozzle 31 of the inkjet heads 30K, 30M, 30Y, 30C at a predetermined timing when the carriage 70 is moving in the main scanning direction. The ink of each color ejected from each nozzle 31 of the inkjet heads 30K, 30M, 30Y, 30C lands on the surface of the recording medium 15. Along with this, an image is recorded on the surface of the recording medium 15.

The mobile device 75 operates until the recording of the image is completed. Therefore, the reciprocating movement of the carriage 70 in the main scanning direction is repeated until the recording of the image is completed. The carrier 20 stops at a predetermined timing after the image recording is completed. The conveyance of the recording medium 15 is also ended as the conveyance device 20 is stopped.

<Inkjet head>
The inkjet head 30 will be described with reference to FIGS. In this description, each direction used to specify the inkjet head 30 is based on the direction in which the inkjet head 30 is provided in the inkjet recording device 10.

The inkjet head 30 includes a flow path body 33, a vibration plate 45, a plurality of piezoelectric elements 50, a plurality of adhesive layers 60, and a restraint 61 (see FIGS. 2 to 4 ). In the inkjet head 30, the flow path body 33 and the vibrating plate 45 are integrated. One vibration plate 45 is provided for one flow path body 33 and a plurality of piezoelectric elements 50. One restraint tool 61 is provided for each of the plurality of piezoelectric elements 50. One piezoelectric element 50 is provided for each nozzle 31. One adhesive layer 60 is provided for each piezoelectric element 50.

In the inkjet head 30, the number of nozzles 31 is four (see FIGS. 2 and 3). Therefore, the inkjet head 30 includes four piezoelectric elements 50. The four piezoelectric elements 50 are piezoelectric elements having the same specifications. However, the plurality of piezoelectric elements 50 have variations in the dimension of the main body in the height direction. The main body of the piezoelectric element 50 will be described later. In the embodiment, when distinguishing the four piezoelectric elements 50, they are referred to as “piezoelectric element 50A”, “piezoelectric element 50B”, “piezoelectric element 50D”, and “piezoelectric element 50E”. When the piezoelectric elements 50A, 50B, 50D and 50E are not distinguished, or when they are collectively referred to, they are referred to as "piezoelectric elements 50". The adhesive layer 60 corresponding to the piezoelectric element 50A is referred to as "adhesive layer 60A", the adhesive layer 60 corresponding to the piezoelectric element 50B is referred to as "adhesive layer 60B", and the adhesive layer 60 corresponding to the piezoelectric element 50D is referred to as "adhesive layer 60A". The layer 60D" is referred to, and the adhesive layer 60 corresponding to the piezoelectric element 50E is referred to as the "adhesive layer 60E" (see FIG. 3). When the adhesive layers 60A, 60B, 60D, and 60E are not distinguished, or when they are collectively referred to, the "adhesive layer 60" is referred to.

In the embodiment, the dimension of the main body of the piezoelectric element 50A in the height direction is “dimension A1”, the dimension of the main body of the piezoelectric element 50B in the height direction is “dimension B1”, and the height of the main body of the piezoelectric element 50D is high. The dimension in the depth direction is "dimension D1", and the dimension in the height direction of the main body portion of the piezoelectric element 50E is "dimension E1" (see FIG. 3). The relationship among the dimensions A1, B1, D1, and E1 is “B1>A1>D1>E1”. The dimension of the adhesive layer 60A in the height direction is "dimension A2", the dimension of the adhesive layer 60B in the height direction is "dimension B2", and the dimension of the adhesive layer 60D in the height direction is "dimension D2". The dimension of the adhesive layer 60E in the height direction is referred to as “dimension E2” (see FIG. 3). The relationship between the dimensions A2, B2, D2 and E2 is “E2>B2>A2>D2”.

The surface of the flow path body 33 on the first side in the height direction serves as the first end surface 32 of the inkjet head 30. Therefore, in the embodiment, the surface of the flow path body 33 on the first side in the height direction is also referred to as the “first end surface 32 ”. The surface on the second side in the height direction of the flow path body 33, which is the side opposite to the first end surface 32, is referred to as the "second end surface 34". A plurality of nozzles 31 are formed on the first end surface 32 of the flow path body 33 (see FIG. 3 ). In the inkjet head 30, four nozzles 31 are arranged in one line at equal intervals in the sub-scanning direction (see FIGS. 2 and 3). However, the number and arrangement of such nozzles 31 are examples. The number and arrangement of the nozzles 31 are appropriately determined in consideration of various conditions. A supply port 35 and an internal flow path 36 are formed in the flow path body 33 (see FIGS. 2 and 4). The supply port 35 is connected to the connection channel of the corresponding color among the connection channels 83K, 83M, 83Y, and 83C. The ink passes through the supply port 35 and is supplied to the inkjet head 30. The internal flow path 36 connects the supply port 35 and the plurality of nozzles 31. The ink flowing in from the supply port 35 flows through the internal flow path 36 and reaches the plurality of nozzles 31.

The internal flow path 36 includes a main flow path 37 and a plurality of tributary flow paths 38 (see FIG. 4). That is, in the inkjet head 30, the main channel 37 and the plurality of tributary channels 38 form the internal channel 36. The main flow path 37 is a flow path continuous from the supply port 35. The main flow path 37 is formed in a state corresponding to the plurality of nozzles 31. That is, the main flow path 37 is formed in the sub-scanning direction like the plurality of nozzles 31. The ink flowing in from the supply port 35 flows in the main flow path 37. The plurality of tributary channels 38 are channels branched from the main channel 37. The plurality of tributary channels 38 are connected to the plurality of nozzles 31, respectively. The ink flowing from the main flow path 37 flows through the tributary flow paths 38 and reaches the nozzles 31.

The tributary channel 38 includes a pressure chamber 39, a first channel section 42, and a second channel section 43. That is, the pair of pressure chambers 39, the first flow path portion 42, and the second flow path portion 43 form one tributary flow path 38. The pressure chamber 39 includes an inflow port 40 and an outflow port 41. The inflow port 40 serves as an ink inlet to the pressure chamber 39. The outlet 41 serves as an outlet for the ink from the pressure chamber 39. The outlet 41 is provided on the third side in the main scanning direction with respect to the inlet 40. The ink that has flowed in through the inflow port 40 flows through the pressure chamber 39 from the fourth side to the third side in the main scanning direction, and then flows out through the outflow port 41. In the flow path body 33, a part of the internal flow path 36 is in an open state at the second end face 34. That is, the second side of the pressure chamber 39 in the height direction is opened at the second end face 34 (see FIG. 5).

The first flow path portion 42 is connected to the main flow path 37 and the inflow port 40 (see FIG. 4 ). That is, the first flow path portion 42 connects the main flow path 37 and the pressure chamber 39. The ink flowing from the main flow path 37 flows through the first flow path portion 42 and flows into the pressure chamber 39. The second flow path portion 43 is connected to the outflow port 41 and the nozzle 31. That is, the second flow path portion 43 connects the pressure chamber 39 and the nozzle 31. The ink flowing out of the pressure chamber 39 flows through the second flow path portion 43 and reaches the nozzle 31.

The vibration plate 45 is provided on the second side of the flow path body 33 in the height direction. For example, the diaphragm 45 is attached to the second end surface 34. The vibration plate 45 covers the second side in the height direction of the pressure chamber 39 in the above-described open state on the second end face 34 (see FIGS. 3 to 6). Along with this, the portion P of the vibration plate 45 becomes a part of the wall surface of the internal flow path 36. That is, the portion P of the vibration plate 45 forms a wall surface on the second side in the height direction of the pressure chamber 39. In the diaphragm 45 shown in FIGS. 5 and 6, a three-dimensional portion (two-dot chain line) with a dot pattern corresponds to the portion P of the diaphragm 45. The diaphragm 45 is formed of, for example, a sheet made of a conductive material. Stainless steel is exemplified as the conductive material forming the diaphragm 45. However, the diaphragm 45 may be made of a conductive material that is different from this. Further, the diaphragm 45 may be formed of a sheet made of an electrically insulating material. The material of the sheet forming the vibration plate 45 is appropriately determined in consideration of various conditions. The thickness (dimension in the height direction) of the vibration plate 45 is set to several tens to several hundreds μm.

The piezoelectric element 50 has the shape of a regular square prism that is vertically long in the height direction in the following state (see FIGS. 2, 5 and 6). In the above-described state, the drive signal is not applied to the piezoelectric element 50, and the piezoelectric element 50 is in an undeformed state (see “first state” in FIG. 4). However, the piezoelectric element 50 may have a shape different from the regular square pole shape. For example, the piezoelectric element 50 may have a quadrangular prism shape different from the regular quadrangular prism shape. Further, the piezoelectric element 50 may have a polygonal column shape or a column shape different from the quadrangular column shape. The bottom shape of the columnar piezoelectric element 50 is appropriately determined in consideration of various conditions.

Although not described above, the inkjet recording device 10 is provided with the same number of signal lines 65 and 66 as the plurality of piezoelectric elements 50 (see FIG. 2 ). In other words, one set of signal lines 65 and 66 is provided for one piezoelectric element 50. The plurality of piezoelectric elements 50 are electrically connected to the head drive unit 92 and each switch in the switch unit 93 via a plurality of sets of signal lines 65 and 66 (see FIGS. 2, 5 and 6). That is, the piezoelectric element 50 is electrically connected to the signal line 65 electrically connected to the head drive unit 92. Further, the piezoelectric element 50 is electrically connected to the signal line 66 electrically connected to the switch in the switch section 93. A drive signal flows through the signal lines 65 and 66. That is, the drive signal output from the head drive unit 92 flows to the next signal line 65, 66 of the plurality of sets of signal lines 65, 66. The above-mentioned signal lines 65 and 66 are a combination of the signal line 66 connecting the switch in the closed state and the piezoelectric element 50, and the signal line 65 connecting the piezoelectric element 50 and the head drive unit 92.

The piezoelectric element 50 is a d33 mode laminated piezoelectric element (see FIGS. 3 to 6). The piezoelectric element 50 includes a plurality of internal electrodes 51, a plurality of internal electrodes 52, a plurality of piezoelectric layers 53, and external electrodes 54 and 55. The piezoelectric element 50 also includes a spacer 56. However, in the inkjet head 30, the piezoelectric elements 50 that do not include the spacer 56 may be included in the plurality of piezoelectric elements 50. The piezoelectric element 50A includes a spacer 56A, the piezoelectric element 50B does not include the spacer 56, the piezoelectric element 50D includes a spacer 56D, and the piezoelectric element 50E includes a spacer 56E (see FIG. 3 ). In the embodiment, the spacers 56A, 56D, and 56E are referred to as "spacers 56" when they are not distinguished from each other or when they are collectively referred to. Further, the portion next to the piezoelectric element 50 is referred to as a "main body portion". In the piezoelectric element 50 including the spacer 56 (see “Piezoelectric elements 50A, 50D, and 50E”), the main body portion is a portion of the piezoelectric element 50 excluding the spacer 56 and does not include the spacer 56 (“the piezoelectric element 50B”). )), the piezoelectric element 50 itself (see FIG. 3). The piezoelectric element 50B does not include the spacer 56 and is formed by the main body portion. Therefore, the “main body portion of the piezoelectric element 50B” is substantially synonymous with the “piezoelectric element 50B”. In the piezoelectric element 50, the plurality of inner electrodes 51, the plurality of inner electrodes 52, the plurality of piezoelectric layers 53, and the outer electrodes 54 and 55 are provided in the main body portion.

In the piezoelectric element 50, the same number of internal electrodes 51 and 52 are provided. The internal electrodes 51, 52 are made of a conductive material. The piezoelectric layer 53 is made of a piezoelectric material. As a conductive material forming the internal electrodes 51 and 52, silver palladium (Ag/Pd) is exemplified. Examples of the piezoelectric material forming the piezoelectric layer 53 include piezoelectric ceramics. An example of piezoelectric ceramics is lead zirconate titanate (PZT). However, in the piezoelectric element 50, known conductive materials and piezoelectric materials are used as the conductive material and the piezoelectric material.

In the piezoelectric element 50, the internal electrodes 51 and 52 and the piezoelectric layer 53 are alternately stacked in the height direction. For example, the internal electrodes 51, 52 and the piezoelectric layer 53 are the internal electrode 51, the piezoelectric layer 53, the internal electrode 52, the piezoelectric layer 53, the internal electrode 51,... Are alternately laminated in this order (see FIGS. 4 to 6). In the piezoelectric element 50, the internal electrodes 51 and 52 are provided alternately in the main scanning direction. In the piezoelectric element 50, the piezoelectric layer 53 sandwiched between the internal electrodes 51 and 52 is deformed in the stacking direction in response to the application of the drive signal. The stacking direction is the direction in which the internal electrodes 51, 52 and the piezoelectric layer 53 are stacked on the piezoelectric element 50. Therefore, in the inkjet head 30, the piezoelectric element 50 is deformed in the height direction (see FIG. 4).

The piezoelectric element 50 is a large piezoelectric element that can be deformed by 100 nm or more. As a reference example, in a known inkjet head, the amount of deformation of the piezoelectric element is about several tens of nm. The plurality of piezoelectric elements 50 are deformed in the height direction by a predetermined amount of 100 nm or more according to the application of the drive signal. The piezoelectric element 50 generates a force of about 300 N when deformed in the height direction according to the application of the drive signal. Therefore, the inkjet head 30 can eject high-viscosity ink from the nozzle 31. In the main body portion of the piezoelectric element 50, non-deformable portions are provided on the first side and the second side in the height direction (for the "non-deformable portion" of the piezoelectric element 50A, see FIG. 5). The non-deformed portion is made of the same piezoelectric material as the piezoelectric layer 53. The two non-deformed portions do not include the internal electrodes 51 and 52. Therefore, the two non-deformable portions do not deform in the height direction when a drive signal is applied to the piezoelectric element 50.

The external electrode 54 is provided along the height direction on the side surface of the main body portion of the piezoelectric element 50 on the third side in the main scanning direction (see FIGS. 4 to 6 ). The outer electrode 54 is electrically connected to the next portion of the inner electrode 51. The aforementioned portion is the outer peripheral portion of the internal electrode 51 on the third side in the main scanning direction. In the piezoelectric element 50, the outer peripheral portion of the internal electrode 51 on the third side in the main scanning direction is exposed on the side surface of the main body portion on the third side in the main scanning direction. The outer electrode 54 is not electrically connected to any of the inner electrodes 52. The external electrode 55 is provided along the height direction on the side surface of the main body portion of the piezoelectric element 50 on the fourth side in the main scanning direction (see FIGS. 4 to 6 ). The outer electrode 55 is electrically connected to the next part of the inner electrode 52. The aforementioned portion is the outer peripheral portion of the internal electrode 52 on the fourth side in the main scanning direction. In the piezoelectric element 50, the outer peripheral portion of the internal electrode 52 on the fourth side in the main scanning direction is exposed on the side surface of the main body portion on the fourth side in the main scanning direction. The external electrode 55 is not electrically connected to any of the internal electrodes 51. The side surface of the main body portion of the piezoelectric element 50 is the surface (wall surface) of the main body portion along the height direction.

The external electrode 54 is electrically connected to the signal line 65, and the external electrode 55 is electrically connected to the signal line 66 (see FIG. 2). Brazing, for example, is adopted as a method of joining the above-mentioned respective connections. An example of brazing is soldering. However, the above-mentioned respective connections may be performed by a joining method different from brazing. As a joining method different from brazing, a method using a conductive adhesive is exemplified.

The piezoelectric elements 50A, 50B, 50D, and 50E are provided on the surface of the diaphragm 45 on the second side in the height direction with the stacking direction aligned with the height direction (see FIG. 3 ). Further, the piezoelectric elements 50A, 50B, 50D, and 50E are provided on the second surface in the height direction of the diaphragm 45, one at each of the four portions P of the diaphragm 45. Therefore, in the inkjet head 30, the piezoelectric elements 50A, 50B, 50D and 50E are provided side by side at equal intervals in the sub-scanning direction. In the embodiment, of the four portions P of the vibration plate 45, the portion P corresponding to the piezoelectric element 50A is referred to as "portion PA", and the portion P corresponding to the piezoelectric element 50B is referred to as "portion PB". The part P corresponding to 50D is called "part PD", and the part P corresponding to the piezoelectric element 50E is called "part PE" (see FIG. 3). When the portions PA, PB, PD, PE of the diaphragm 45 are not distinguished, or are collectively referred to, they are referred to as “portion P” of the diaphragm 45.

The adhesive layer 60 is a resin layer obtained by curing an adhesive. The adhesive layer 60 is preferably a resin layer having a durometer hardness of D70 or more. As the adhesive forming the adhesive layer 60, the following adhesives can be adopted. That is, the adhesive layer 60 may be made of an electrically insulating adhesive. In this case, the adhesive layer 60 is a resin layer obtained by curing an electrically insulating adhesive. The adhesive layer 60 may be made of an adhesive having the following properties. The above-mentioned property is a property of being softened by a specific solvent. In this case, the adhesive layer 60 is a resin layer obtained by curing an adhesive having the above-mentioned properties. Examples of the adhesive having the above-mentioned properties include anaerobic curable adhesives, moisture curable adhesives, and ultraviolet curable adhesives. However, the epoxy resin adhesive is not included in the adhesive having the above-mentioned properties. Further, the adhesive layer 60 may be a thermosetting adhesive. In this case, the adhesive layer 60 is a resin layer obtained by curing a thermosetting adhesive. The adhesive forming the adhesive layer 60 is appropriately determined in consideration of various conditions. However, the plurality of adhesive layers 60A, 60B, 60D, 60E are formed by the same adhesive.

The adhesive layer 60 is provided between the portion P of the vibration plate 45 and the piezoelectric element 50 (see FIGS. 3 to 6). The adhesive layer 60 is formed between the surface of the vibration plate 45 on the second side in the height direction of the portion P and the surface of the piezoelectric element 50 on the first side in the height direction (bottom surface of the piezoelectric element 50). The portion P and the piezoelectric element 50 are bonded. That is, the adhesive layer 60A bonds the portion PA of the vibration plate 45 and the piezoelectric element 50A. The adhesive layer 60B bonds the portion PB of the vibration plate 45 and the piezoelectric element 50B. The adhesive layer 60D bonds the portion PD of the vibration plate 45 and the piezoelectric element 50D. The adhesive layer 60E bonds the portion PE of the vibration plate 45 and the piezoelectric element 50E.

As described above, the adhesive layers 60A, 60B, 60D, and 60E have variations in the height-direction dimensions A2, B2, D2, and E2. That is, when the inkjet head 30 is manufactured, a predetermined amount of adhesive is applied to the portions PA, PB, PD, PE of the vibration plate 45. After that, the main body of the piezoelectric element 50A is placed on the adhesive applied to the portion PA of the vibration plate 45, and is pressed to the first side in the height direction. Further, the main body portion of the piezoelectric element 50B is placed on the adhesive applied to the portion PB of the vibration plate 45 and pressed against the first side in the height direction. Further, the main body portion of the piezoelectric element 50D is placed on the adhesive applied to the portion PD of the vibration plate 45 and is pressed against the first side in the height direction. Furthermore, the main body portion of the piezoelectric element 50E is placed on the adhesive applied to the portion PE of the vibration plate 45 and is pressed against the first side in the height direction. The aforementioned variation is caused by, for example, one or both of a slight change in the amount of adhesive applied and a slight change in the pressing force.

In the inkjet head 30, the dimensions A1, B1, D1, and E1 vary, and the dimensions A2, B2, D2, and E2 vary. Therefore, in the inkjet head 30, the heights of the respective surfaces on the second side in the height direction of the main body portions of the piezoelectric elements 50A, 50B, 50D, and 50E vary in the bonded state (see FIG. 3). In the bonded state, the main body of the piezoelectric element 50A is provided on the portion PA of the diaphragm 45 via the adhesive layer 60A, and the main body of the piezoelectric element 50B is provided on the portion PB of the diaphragm 45 via the adhesive layer 60B. The main body of the piezoelectric element 50D is provided on the portion PD of the diaphragm 45 via the adhesive layer 60D, and the main body of the piezoelectric element 50E is provided on the portion PE of the diaphragm 45 via the adhesive layer 60E. It can be said that the bonded state is a state in which all the piezoelectric elements 50 are provided on the portion P of the vibration plate 45 via the bonding layer 60. The above-mentioned variations that occur in the bonded state include variations in the dimensions A1, B1, D1, and E1 and variations in the dimensions A2, B2, D2, and E2, as well as during assembly of the main body portions of the piezoelectric elements 50A, 50B, 50D, and 50E. It is also caused by the inclination of the main body portion that occurs in some or all of the main body portions.

In the embodiment, the relationship between the heights of the surfaces of the piezoelectric elements 50A, 50B, 50D, and 50E on the second side in the height direction of the main body of the piezoelectric elements 50A, 50B, 50D, and 50E in the adhering state is as follows. Second surface in the height direction “B1+B2”, height of the second side surface in the height direction of the body portion of the piezoelectric element 50E “E1+E2”, second height direction of the body portion of the piezoelectric element 50A. The height of the side surface is “A1+A2” and the height of the second side surface in the height direction of the main body of the piezoelectric element 50D is “D1+D2” (B1+B2>E1+E2>A1+A2>D1+D2 See FIG. 3).

The inventor conducted various studies in developing the inkjet head 30. In this examination, the following variations were observed in the following dimensions. That is, a variation of about 10 μm was observed in the dimension of the main body portion of the plurality of piezoelectric elements 50 in the height direction (see “Dimensions A1, B1, D1, E1”). In addition, a variation of about 40 μm was observed in the dimension in the height direction of the plurality of adhesive layers 60 (see “Dimensions A2, B2, D2, E2”). Furthermore, a variation of about 70 to 80 μm was observed in the height of each surface on the second side in the height direction of the main body portion of the plurality of piezoelectric elements 50 in the bonded state.

In the inkjet head 30, the following operation is performed when the heights of the surfaces on the second side in the height direction of the main body portions of the plurality of piezoelectric elements 50 are not equal in the bonded state. That is, a predetermined one main body portion of the piezoelectric element 50 is selected from the plurality of main body portions of the piezoelectric element 50 as a reference. Then, the height of the surface of the other piezoelectric element 50 on the second side in the height direction is adjusted to the height of the reference surface of the piezoelectric element 50 on the second side in the height direction. .. For example, in the piezoelectric elements 50A, 50B, 50D, and 50E, the height of each surface on the second side in the height direction of the body portions of the piezoelectric elements 50A, 50D, and 50E is based on the body portion of the piezoelectric element 50B having the highest height. Adjusted. In this case, the piezoelectric element 50A includes the spacer 56A on the second side in the height direction. The spacer 56A is a member having a dimension A3 in the height direction of "(B1+B2)-(A1+A2)". The piezoelectric element 50D includes a spacer 56D on the second side in the height direction. The spacer 56D is a member whose dimension D3 in the height direction is "(B1+B2)-(D1+D2)". The piezoelectric element 50E includes a spacer 56E on the second side in the height direction. The spacer 56E is a member having a height dimension E3 of "(B1+B2)-(E1+E2)". As described above, in the piezoelectric elements 50A, 50B, 50D, and 50E, the heights of the respective surfaces on the second side in the height direction are set equal by the spacers 56A, 56D, and 56E.

The spacer 56 may be a resin layer obtained by curing an adhesive. In this case, the spacer 56 is preferably a resin layer having a durometer hardness of D70 or more, like the adhesive layer 60. As the adhesive forming the spacer 56, the same adhesive as the adhesive layer 60 may be adopted. In addition, the spacer 56 may be a metal sheet. In this case, the metal sheet includes a metal foil. For example, a stainless steel sheet can be used as the spacer 56. In addition, as the spacer 56, a sheet made of aluminum, copper, or brass may be adopted. Whether the spacer 56 is a resin layer or a metal sheet is appropriately determined in consideration of various conditions. However, the plurality of spacers 56 may have the same aspect. Further, the plurality of spacers 56 may be formed of the same material in any of the modes.

The restraint tool 61 is provided on the second side in the height direction of each piezoelectric element 50A, 50B, 50D, 50E in a state of being associated with the plurality of piezoelectric elements 50A, 50B, 50D, 50E (see FIGS. 2 and 3). ). The restraint tool 61 has the above-mentioned surfaces of the plurality of piezoelectric elements 50A, 50B, 50D, 50E (the plurality of piezoelectric elements 50A, 50B, 50D, Touch each top surface of 50E). In the inkjet head 30, the restraint tool 61 is integrated with the flow path body 33. The restraint tool 61 is fixed to, for example, the outer edge portion of the flow path body 33. A fastener is used for this fixing. A screw is illustrated as a fastener. 2-4, illustration of a fastener is abbreviate|omitted.

When the plurality of piezoelectric elements 50A, 50B, 50D, 50E are deformed in the height direction in response to the application of the drive signal, the restraint tool 61 receives the force generated by the piezoelectric elements 50A, 50B, 50D, 50E. Therefore, the restraint tool 61 may be made of a material having high hardness. Further, the restraint tool 61 may be formed of a highly rigid material. For example, the restraint tool 61 may be made of metal. Examples of the metal forming the restraint tool 61 include aluminum and stainless steel. In addition, the restraint tool 61 may be made of ceramics.

5 and 6, the range corresponding to the piezoelectric element 50A is shown. Here, the difference between the ranges corresponding to the piezoelectric elements 50A, 50B, 50D, 50E is the presence or absence of the spacer 56 in the piezoelectric element 50 (see "Piezoelectric elements 50A, 50B") and the shapes of the spacers 56A, 56D, 56E ( “Piezoelectric elements 50A, 50D, 50E”) and adhesive layers 60A, 60B, 60D, 60E. Therefore, the illustration of the range corresponding to the piezoelectric elements 50B, 50D, and 50E corresponding to FIGS. 5 and 6 is substantially the same as or similar to FIGS. Therefore, in the embodiment, the illustration of the range corresponding to the piezoelectric elements 50B, 50D, and 50E corresponding to FIGS.

<Ink ejection>
Ink ejection from the nozzles 31 will be described with reference to FIG. FIG. 4 shows a range corresponding to the piezoelectric element 50A. However, in the inkjet head 30, the ejection of ink by the piezoelectric elements 50 of the piezoelectric elements 50A, 50B, 50D, and 50E is similarly performed. Therefore, in the following, the ejection of ink by the piezoelectric elements 50 of the piezoelectric elements 50A, 50B, 50D, and 50E will be described without distinction.

At the time of recording an image, the controller 91 controls the output of the drive signal. In response to this control, the head drive unit 92 starts outputting the drive signal. The head drive unit 92 outputs a drive signal at a predetermined cycle. Further, the controller 91 generates an ejection signal according to the image data. The image data is data corresponding to the image recorded on the recording medium 15. The image data is generated using a predetermined application program and stored in the storage of the controller 91. The controller 91 acquires image data from the storage. However, the image data may be input from an external device (not shown) connected to the control device 90. The generated ejection signal is input to the switch unit 93. The ejection signal is a pulse signal having a predetermined voltage value. In the switch unit 93, a predetermined switch among the built-in switches is closed according to the inputted discharge signal.

When a drive signal is output from the head drive unit 92 at the timing when a predetermined switch built in the switch unit 93 is closed, one of the plurality of piezoelectric elements 50A, 50B, 50D, and 50E on the diaphragm 45 is output. A drive signal is applied to the next piezoelectric element 50. The above-mentioned piezoelectric element 50 is a piezoelectric element connected to the closed switch via the signal line 66. The piezoelectric element 50 to which the drive signal is applied is deformed in the height direction (see “second state” in FIG. 4). However, the piezoelectric element 50 contacts the restraint tool 61 on the second side in the height direction. Therefore, the direction in which the piezoelectric element 50 is deformed is the first side in the height direction. The amount of deformation of the piezoelectric element 50 is a predetermined amount of 100 nm or more, as described above. The piezoelectric element 50 to which the drive signal is applied is deformed toward the first side in the height direction by a predetermined amount of 100 nm or more, so that the portion P of the vibration plate 45 that is in contact with the piezoelectric element 50 corresponds to the deformation amount of the piezoelectric element 50. It deforms to the first side in the height direction. Along with this, the volume of the pressure chamber 39 having the portion P of the diaphragm 45 as an inner wall is reduced by an amount corresponding to the amount of deformation of the portion P of the diaphragm 45. The pressure due to the reduction of the volume of the pressure chamber 39 acts on the ink inside the reduced pressure chamber 39. As a result, ink is ejected from the nozzles 31 connected to the pressure chambers 39 via the second flow path 43. In the second state of FIG. 4, the black circle near the nozzle 31 corresponds to the ink ejected from the nozzle 31.

The piezoelectric element 50 returns to the pre-deformation state due to one or both of the opening of the closed switch and the non-output of the drive signal (see “first state” in FIG. 4 ). The piezoelectric element 50 is repeatedly deformed each time the closing of the switch of the switch unit 93 connected to the piezoelectric element 50 via the signal line 66 and the application of the drive signal of a predetermined cycle match (see FIG. 4). See "Second state"). The switch is closed when the discharge signal is input. When the deformation of the piezoelectric element 50 is repeated, the portion P of the vibration plate 45 corresponding to the piezoelectric element 50, which is repeatedly deformed, is also repeatedly deformed. As a result, ink is repeatedly ejected from the nozzle 31 connected to the pressure chamber 39 having the deformed portion P of the vibration plate 45 as the inner wall via the second flow path portion 43.

<Effects of the embodiment>
According to the embodiment, the following effects can be obtained.

(1) In the inkjet head 30, the restraint tool 61 is provided on the second side in the height direction of the plurality of piezoelectric elements 50A, 50B, 50D, 50E (see FIGS. 3 and 4). The restraint tool 61 restrains deformation of the plurality of piezoelectric elements 50A, 50B, 50D, 50E toward the second side in the height direction (see FIG. 4). In the installed state, the plurality of piezoelectric elements 50A, 50B, 50D, and 50E are set to have the same height on each surface on the second side in the height direction (see FIG. 3 ). The installed state is a state in which all the piezoelectric elements 50 are provided on the portion P of the vibration plate 45 via the adhesive layer 60 (see FIG. 3 ). The plurality of piezoelectric elements 50A, 50B, 50D, 50E are deformed to the first side in the height direction according to the application of the drive signal. Therefore, the plurality of piezoelectric elements 50A, 50B, 50D, and 50E can keep the contact state with the restraint tool 61 constant. Ink ejection can be stabilized by the plurality of nozzles 31. The inkjet recording device 10 can record high-quality images.

(2) In the inkjet head 30, the restraint tool 61 is made of metal or ceramics. Therefore, the hardness of the restraint tool 61 can be increased and the restraint tool 61 with high rigidity can be obtained. The piezoelectric element 50 can be constrained from the second side in the height direction, and the piezoelectric element 50 can be deformed to the first side in the height direction.

(3) In the inkjet head 30, the piezoelectric elements 50A, 50D, 50E include spacers 56A, 56D, 56E (see FIG. 3). Therefore, in the piezoelectric elements 50A and 50B, the height of the second side surface of the piezoelectric element 50A in the height direction is made equal to the height of the second side surface of the piezoelectric element 50B by the spacer 56A in the installed state. Can be done (A1+A2+A3=B1+B2). In the piezoelectric elements 50B and 50D, the height of the second side surface of the piezoelectric element 50D in the height direction is made equal to the height of the second side surface of the piezoelectric element 50B by the spacer 56D in the installed state. (D1+D2+D3=B1+B2). In the piezoelectric elements 50B and 50E, in the installed state, the height of the second side surface of the piezoelectric element 50E in the height direction is made equal to the height of the second side surface of the piezoelectric element 50B by the spacer 56E. Can be obtained (E1+E2+E3=B1+B2). In this case, even in the piezoelectric elements 50A, 50D, 50E, the heights of the respective surfaces on the second side in the height direction can be made equal by the spacers 56A, 56D, 56E in the installed state. That is, in the inkjet head 30, the plurality of piezoelectric elements 50A, 50B, 50D, and 50E can equalize the heights of the surfaces on the second side in the height direction (A1+A2+A3=B1+B2=D1+D2+D3=E1+E2+E3). The plurality of piezoelectric elements 50A, 50B, 50D, and 50E can equalize the contact state of each surface on the second side in the height direction with respect to the restraint tool 61.

By forming the spacer 56 as a resin layer obtained by curing an electrically insulating adhesive, conduction through the spacer 56 can be prevented. The restraint tool 61 can be made of a conductive material. For example, the restraint tool 61 can be made of metal. The spacer 56 can be removed by using a resin layer obtained by curing an adhesive having a property of softening the spacer 56 with a specific solvent. Further, by forming the spacer 56 as a resin layer obtained by curing a thermosetting adhesive, the adhesive can be cured by heating to form the spacer 56.

By using the spacer 56 as a metal sheet, the hardness of the spacer 56 can be increased and the spacer 56 having high rigidity in the height direction can be obtained. It is possible to suppress the spacer 56 from being deformed (elastically deformed) in the height direction when the piezoelectric element 50 is deformed in response to the application of the drive signal. It is possible to prevent the spacer 56 from absorbing the force associated with the deformation of the piezoelectric element 50. The force associated with the deformation of the piezoelectric element 50 can be applied to the portion P of the vibration plate 45 via the adhesive layer 60. When the spacer 56 is a metal sheet, the restraint tool 61 may be formed of an electrically insulating material or a material whose surface is covered with an electrically insulating film. Conduction to the restraint tool 61 side through the spacer 56 can be suppressed.

(4) In the inkjet head 30, the plurality of adhesive layers 60A, 60B, 60D and 60E are resin layers obtained by curing the same adhesive. Therefore, the hardness can be made constant among the plurality of adhesive layers 60A, 60B, 60D, 60E. By making the adhesive layer 60 a resin layer having a durometer hardness of D70 or more, it is possible to prevent the force associated with the deformation of the piezoelectric element 50 from being absorbed by the adhesive layer 60. The force associated with the deformation of the piezoelectric element 50 can be applied to the portion P of the vibration plate 45 via the adhesive layer 60. Further, by forming the adhesive layer 60 as a resin layer obtained by curing an electrically insulating adhesive, it is possible to prevent conduction through the adhesive layer 60. Furthermore, the adhesive layer 60 can be removed by forming the adhesive layer 60 into a resin layer obtained by curing an adhesive having a property of being softened by a specific solvent. The inkjet head 30 may fail. In such a case, the spacer 56 and the adhesive layer 60 are both resin layers made of the above-mentioned adhesive, so that the spacer 56 and the adhesive layer 60 can be removed and the main body portion of the piezoelectric element 50 can be removed from the inkjet head 30. .. The main body of the removed piezoelectric element 50 can be reused for a new inkjet head 30. In addition, by forming the spacer 56 and the adhesive layer 60 with the same adhesive, the spacer 56 and the adhesive layer 60 can match various characteristics such as mechanical characteristics and chemical characteristics.

<Modification>
The embodiment may also be as follows. Some of the configurations of the modified examples described below can be appropriately combined and employed. Hereinafter, points different from the above will be described, and description of the same points will be appropriately omitted.

(1) In the inkjet recording apparatus 10, the recording of an image on the recording medium 15 is performed while the carriage 70 is reciprocally moved in the main scanning direction by the moving device 75 (see FIG. 1). As the inkjet recording apparatus, an apparatus of a type different from the inkjet recording apparatus 10 has been put into practical use. This different type of inkjet recording apparatus includes an inkjet head called a line type. Similar to the above, the following configuration can also be adopted for a line type inkjet head. The above-described configuration is a configuration in which the heights of the surfaces of the plurality of piezoelectric elements 50 on the second side in the height direction are set to be equal in the installed state (see FIG. 3 ). However, in an inkjet recording apparatus including a line-type inkjet head, for example, a plurality of nozzles are arranged in a direction that is the main scanning direction described above, and inkjet heads of each color are arranged on the carriage in a direction that is the sub-scanning direction. Mounted next to each other. The carrying direction is a direction along the direction referred to above as the sub-scanning direction. The line type ink jet head and the ink jet recording apparatus provided with the line type ink jet head have a known configuration which has already been put into practical use. Therefore, other explanations regarding these are omitted.

(2) In the inkjet head 30, the restraint tool 61 is fixed to the outer edge portion of the flow path body 33 (see FIGS. 2 and 4). In the inkjet head, the flow path main body and the restraint tool may be fixed as follows. In this case, the inkjet head includes a frame having a predetermined shape. The flow path body and the restraint tool are fixed to this frame.

(3) In the inkjet head 30, the plurality of piezoelectric elements 50 are provided on the surface of the vibration plate 45 on the second side in the height direction with the stacking direction aligned with the height direction (FIGS. 2 to 4, 6 ). reference). The vibrating plate 45 is integrated and is provided for one of the plurality of piezoelectric elements 50 (see FIGS. 2 and 3). In the inkjet head 30, a plurality of piezoelectric elements 50A, 50B, 50D, 50E are provided on the surface of the integrated diaphragm 45 on the second side in the height direction. The diaphragm 45 may be divided corresponding to one or a predetermined number of piezoelectric elements 50 of two or more. For example, when the piezoelectric element 50 is the four piezoelectric elements 50A, 50B, 50D, and 50E as described above, the vibrating plate 45 has the dividing plates 95, 96, 97, in the sub-scanning direction, as shown in FIG. It is also possible to divide into 98. In FIG. 7, in order to clarify the correspondence with FIGS. 2 to 6, the reference numerals for the respective parts are the same as above.

The division plates 95, 96, 97, 98 are provided on the second end face 34 side by side in the sub-scanning direction in a state of being associated with each pressure chamber 39. The dividing plates 95, 96, 97, 98 form the wall surface on the second side in the height direction of each pressure chamber 39, similarly to the vibrating plate 45 shown in FIGS. Each part of the division plates 95, 96, 97, 98 forming the above-mentioned wall surface of the pressure chamber 39 corresponds to the parts PA, PB, PD, PE (see FIG. 3) of the diaphragm 45 described above. The division plates 95, 96, 97, 98 are sheets similar to the diaphragm 45 shown in FIGS. One piezoelectric element 50 of the plurality of piezoelectric elements 50A, 50B, 50D, 50E is provided on each of the division plates 95, 96, 97, 98 in the same manner as described above. It is possible to suppress transmission of vibration caused by deformation of any one of the plurality of piezoelectric elements 50A, 50B, 50D, and 50E between the division plates 95, 96, 97, 98. When the inkjet head 30 shown in FIG. 7 is cut at the position corresponding to the line KK shown in FIG. 2, the structure is the same as that in FIG.

Unlike FIG. 7, the diaphragm may be divided into two in the sub-scanning direction (not shown), for example. In this case, the divided plates of the diaphragm divided into two are provided on the second end face 34 side by side in the sub-scanning direction in a state of corresponding to the pressure chambers 39. Like the diaphragm 45 shown in FIGS. 2 to 6, each of the two divided diaphragms forms a wall surface on the second side in the height direction of each pressure chamber 39. Each of the two divided diaphragms is a sheet similar to the diaphragm 45 shown in FIGS. When the piezoelectric element 50 is the four piezoelectric elements 50A, 50B, 50D, and 50E as described above, the piezoelectric elements 50A and 50B and the piezoelectric elements 50D and 50E are respectively provided on the respective divided plates of the diaphragm divided into two. It is provided in the same manner as above. It is possible to suppress the vibration caused by the deformation of any one of the plurality of piezoelectric elements 50A, 50B, 50D, and 50E from being transmitted between the diaphragms divided into two. When the diaphragm is divided into a plurality of division plates, the number of divisions is appropriately determined in consideration of various conditions.

10 inkjet recording device, 15 recording medium, 20 carrier 30, 30K, 30M, 30Y, 30C inkjet head, 31 nozzle 32 first end face, 33 flow passage body, 34 second end face, 35 supply port 36 internal flow passage, 37 Main channel, 38 tributary channels, 39 pressure chamber, 40 inflow port 41 outflow port, 42 first flow channel part, 43 second flow channel part, 45 vibration plate 50, 50A, 50B, 50D, 50E piezoelectric element, 51, 52 inside Electrode 53 Piezoelectric layer, 54, 55 External electrode, 56, 56A, 56D, 56E Spacer 60, 60A, 60B, 60D, 60E Adhesive layer, 61 Restraint tool 65, 66 Signal line, 70 Carriage, 71 Stay, 75 Mobile machine 76 , 77 pulley, 78 timing belt, 79 motor 80K, 80M, 80Y, 80C main tank 81K, 81M, 81Y, 81C supply channel 82K, 82M, 82Y, 82C sub-tank 83K, 83M, 83Y, 83C connection channel, 90 control Device, 91 Controller 92 Head drive part, 93 Switch part, 95, 96, 97, 98 Dividing plate A1, A2, A3, B1, B2, D1, D2, D3, E1, E2, E3 Dimensions P, PA, PB , PD, PE diaphragm (45) part

Claims (11)

It includes a first nozzle and a second nozzle for ejecting ink on the surface on the first side in the height direction, and internally supplies the ink to the first tributary channel and the second nozzle for flowing the ink to the first nozzle. A flow path body including an internal flow path including a second tributary flow path,
Vibration provided on the second side of the flow path body in the height direction and including a first portion which is a part of a wall surface of the first tributary flow path and a second portion which is a part of a wall surface of the second tributary flow path. A board,
It is provided on the surface of the first portion on the second side in the height direction, is deformed in the height direction in response to the application of a drive signal that is a pulse signal, and ejects ink from the first nozzle. A first piezoelectric element,
The second laminated portion is provided on a surface of the second portion on the second side in the height direction, is deformed in the height direction according to the application of the drive signal, and ejects ink from the second nozzle. A piezoelectric element,
A resin layer obtained by curing an adhesive, and a first adhesive layer that adheres the first portion and the first piezoelectric element,
A resin layer obtained by curing the same adhesive as the first adhesive layer, and a second adhesive layer for bonding the second portion and the second piezoelectric element,
It is provided on the second side in the height direction of the first piezoelectric element and the second piezoelectric element, and restrains the deformation of the first piezoelectric element and the second piezoelectric element to the second side in the height direction. And a restraint,
In the first piezoelectric element and the second piezoelectric element, the first piezoelectric element is provided in the first portion via the first adhesive layer, and the second portion is provided in the second portion via the second adhesive layer. An inkjet head in which a height of each surface on the second side in the height direction is set to be equal in a state where a piezoelectric element is provided. The inkjet head according to claim 1, wherein the restraint is made of metal or ceramics. The first piezoelectric element includes, on the second side in the height direction, a first spacer that adjusts the height of a surface of the first piezoelectric element on the second side in the height direction. Item 2. The inkjet head according to item 2. The second piezoelectric element, on the second side in the height direction, includes a second spacer for adjusting the height of the surface of the second piezoelectric element on the second side in the height direction,
The inkjet head according to claim 3, wherein the second spacer is made of the same material as the first spacer. The inkjet head according to claim 3 or 4, wherein the first spacer is a resin layer obtained by curing an electrically insulating adhesive. The inkjet head according to any one of claims 3 to 5, wherein the first spacer is a resin layer obtained by curing an adhesive having a property of being softened by a specific solvent. The inkjet head according to any one of claims 3 to 5, wherein the first spacer is a resin layer obtained by curing a thermosetting adhesive. The inkjet head according to any one of claims 3 to 7, wherein the first spacer is a resin layer obtained by curing the same adhesive as the first adhesive layer. The inkjet head according to claim 3 or 4, wherein the first spacer is a metal sheet. The inkjet head according to any one of claims 1 to 9, wherein the first adhesive layer is a resin layer having a durometer hardness of D70 or more. An inkjet head according to any one of claims 1 to 10,
An inkjet recording apparatus, comprising: a head drive unit that generates the drive signal.

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