JP7110126B2 - Inkjet head, inkjet device, and method for manufacturing inkjet head - Google Patents

Description

Embodiments of the present invention relate to an inkjet head, an inkjet device, and an inkjet head manufacturing method.

A share mode shared wall type inkjet head having a plurality of pressure chambers, in which a plurality of pressure chambers communicating with nozzles and a plurality of air chambers disposed between the pressure chambers are alternately provided in a predetermined parallel direction. configuration is known. In such a liquid ejection head, a nozzle plate is bonded to an actuator base having a plurality of grooves forming pressure chambers and air chambers by, for example, an adhesive.

JP 2010-131939 A

In such an inkjet head, it is difficult to control the application position of the adhesive, and the adhesive may protrude into the pressure chamber. If the protruding adhesive hits the nozzle, it adversely affects the ejection performance of the ink droplets and causes deterioration in print quality. On the other hand, if the amount of adhesive applied is reduced in order to suppress the protrusion of the adhesive, pressure resistance is impaired due to insufficient bonding strength.

The problem to be solved by the present invention is to provide an inkjet head, an inkjet device, and an inkjet head manufacturing method that can ensure ejection performance and pressure resistance.

An inkjet head according to one embodiment includes a nozzle plate and an actuator base. The nozzle plate has multiple nozzles. The actuator base has a plurality of walls, a plurality of first grooves and a plurality of second grooves. The wall has a joint surface that is joined to the nozzle plate. A first groove forms a pressure chamber disposed on one side of the wall portion and communicating with the plurality of nozzles. A second groove is disposed on the other side of the wall. The nozzle plate and the actuator base are joined with an adhesive between the joining surfaces of the plurality of wall portions and the nozzle plate. In a majority of the wall portions among the plurality of wall portions, the adhesive is distributed more to the second groove side than to the first groove side.

1 is an exploded perspective view showing the configuration of an inkjet head according to a first embodiment; FIG. FIG. 2 is a perspective view showing a configuration of part of the inkjet head; Sectional drawing which shows the structure of a part of inkjet head. Explanatory drawing which shows the manufacturing method of the same inkjet head. FIG. 2 is an explanatory diagram showing the configuration of an inkjet printer using the same inkjet head. FIG. 5 is an explanatory diagram showing a method of manufacturing an inkjet head according to another embodiment;

An inkjet head 1, which is a liquid ejection head, and an inkjet printer 100, which is an inkjet device, according to the first embodiment will be described below with reference to FIGS. 1 to 5. FIG. In each figure, for the sake of explanation, the configuration is shown enlarged, reduced, or omitted as appropriate. Arrows X, Y, and Z in the drawing indicate three directions orthogonal to each other. In this embodiment, the first direction of the inkjet head 1 is the X axis, the second direction is the Y axis, and the third direction is the Z axis.

FIG. 1 is an exploded perspective view showing part of the inkjet head 1 according to the first embodiment, FIG. 2 is a perspective view showing the configuration of part of the inkjet head 1, and FIG. It is the same cross-sectional view of.

The inkjet head 1 shown in FIGS. 1 to 6 is a liquid ejection head, and includes an actuator base 20, a nozzle plate 30, and a frame 40. As shown in FIG. The inkjet head 1 is a share mode shared wall type inkjet head.

The actuator base 20 has a substrate 21 and a laminated piezoelectric body 22 . The actuator base 20 is joined to face the nozzle plate 30 with the frame 40 interposed therebetween to form a common chamber C3 with the nozzle plate 30 .

The substrate 21 is configured in a rectangular plate shape. Substrate 21 is preferably made of PZT, ceramics, glass, machinable ceramics, or a material containing these. The substrate 21 has a plurality of supply holes 21a and recovery holes 21b, which are through holes penetrating in the thickness direction.

The laminated piezoelectric body 22 is formed on the nozzle plate 30 side surface of the substrate 21 . In this embodiment, two laminated piezoelectric bodies 22 extending along a predetermined first direction are arranged in parallel on the main surface of the substrate 21 . The laminated piezoelectric member 22 is configured by laminating two piezoelectric members. The piezoelectric member is made of, for example, a PZT (lead zirconate titanate) piezoelectric ceramic material. In addition, lead-free piezoelectric ceramics such as KNN (potassium sodium niobate) may be used as the piezoelectric member in consideration of the environment. The two piezoelectric members are polarized so that their polarization directions are opposite to each other, and are adhered via an adhesive layer.

A groove row 23A having a plurality of grooves 23 arranged in the first direction is formed on the end surface of the laminated piezoelectric body 22 facing the nozzle plate 30 . The cross-sectional shape of the laminated piezoelectric body 22 along the first direction and the third direction is a comb shape. Between adjacent grooves 23, column-shaped partitions 25 made of piezoelectric elements are formed. The partition wall 25 serves as a drive element that changes the volume of the groove 23 .

In the groove row 23A, a plurality of first grooves 23a and a plurality of second grooves 23b are alternately arranged in the first direction. The plurality of grooves 23 are arranged in parallel in the first direction, extend in the second direction, and are arranged parallel to each other. The grooves 23a and 23b are formed over the entire length of the laminated piezoelectric body 22 in the second direction. That is, the grooves 23a and 23b are opened on the nozzle plate 30 side. Electrodes 24 are formed on the inner bottom and both side surfaces of the grooves 23a and 23b.

Both ends of the first groove 23a in the second direction are open within the openings 41a of the frame member 41 and communicate with the common chamber C3. The first grooves 23 a are provided at positions facing the nozzles 31 , and are provided in the same number as the nozzles 31 . The first groove 23a constitutes a pressure chamber C1 communicating with the common chamber C3 and communicating with the nozzle 31. As shown in FIG.

Cover walls 27 made of photocurable resin are provided at both ends of the second groove 23b in the second direction. The cover wall 27 closes both ends of the second groove 23b in the second direction. The second groove 23b is closed by a cover wall 27 covering both ends in the second direction, a nozzle plate 30 covering in the third direction, and partition walls 25 arranged on both sides in the first direction. constitute an air chamber C2 separated from.

The partition wall portion 25 is, for example, a rectangular parallelepiped wall-like member arranged between the plurality of grooves 23 and extending along the second direction. The partition wall 25 is composed of piezoelectric elements in which a first piezoelectric element 25a and a second piezoelectric element 25b laminated on the first piezoelectric element 25a are laminated. A joint surface 25 c , which is an end face of the partition wall 25 on the nozzle plate 30 side, is joined to the nozzle plate 30 via an adhesive 50 . By bonding the joint surface 25c of the partition wall 25 to the nozzle plate 30, the air chamber C2 formed by the second groove 23b is closed.

For the adhesive 50, for example, an epoxy-based adhesive effective in ink resistance is used. For example, in this embodiment, an adhesive that is heated to 80° C. during curing is used. The adhesive 50 is distributed closer to the second groove 23b disposed on the other side than the first groove 23a disposed on one side of the partition wall 25 .

In the inkjet head 1, in the majority, for example, 80% or more of the nozzles 31, the position of the adhesive 50 between the opposing partition wall portions 25 is closer to the second groove 23b than the center of the partition wall portion 25. The edge of the application area of the adhesive 50 on the side of the first groove 23 a is retracted from the edge of the partition wall 25 without protruding. In addition, the amount of the adhesive 50 applied is not uniform, and the amount applied on the side of the second groove 23b is large. The amount of protrusion of the adhesive 50 from the joint surface 25c of the partition wall 25 toward the groove side is larger on the second groove 23b side than on the first groove 23a side.

As an example, in the present embodiment, in the partition 25 between the pressure chamber C1 facing 80% or more of the nozzles 31 out of the plurality of nozzles 31 and the adjacent air chamber C2, the adhesive 50 is applied to the area where the adhesive 50 is applied. is closer to the second groove 23b than the center of the partition wall 25, and is positioned so as not to protrude into the first groove 23a.

Here, as an example of the manufacturing process of the inkjet head 1, a method of bonding the actuator base 20 and the nozzle plate 30 by biasing the adhesive 50 toward the second groove 23b will be described. In the manufacturing process of the inkjet head 1, the bonding process for bonding the actuator base 20 and the nozzle plate 30 includes a coating process of coating the bonding surface 25c of the partition wall portion 25 with the adhesive 50, and a bonding process of the actuator base 20 after the coating of the adhesive 50. and a curing step of curing the adhesive 50 .

In this embodiment, as an example, as shown in FIG. 4, in the application process of applying the adhesive 50 to the bonding surface 25c, the adhesive 50 is applied to the bonding surface 25c of the partition wall 25 on the second groove side. Apply to the position of As a specific example, for example, the center of the application area of the adhesive 50 is positioned closer to the second groove 23b than the center of the bonding surface 25c. In this embodiment, the coating is applied to half the area on the second groove side of the center. As described above, by applying the adhesive by shifting the application position, the ink jet head 1 in which the position of the adhesive 50 is biased is obtained.

The electrode 24 is a conductive film made of a conductive material such as nickel. The electrode 24 is formed on the bottom of the first groove 23 a and connected to the wiring pattern 26 on the substrate 21 . The electrodes 24 are formed by, for example, a vacuum deposition method, an electroless nickel plating method, or the like. The electrodes 24 may be made of gold, copper, or the like, for example. Alternatively, two or more conductive films may be laminated.

The wiring pattern 26 (wiring electrode) is a conductive film formed of a conductive material such as nickel similar to the electrode 24 and having a predetermined pattern shape. The wiring pattern 26 is formed on the main surface of the substrate 21 . The wiring pattern 26 is formed at the same time when the electrodes 24 are formed by a technique such as vacuum deposition or electroless plating. The wiring pattern 26 is formed outside the frame member 41, and a drive circuit can be connected to the portion exposed outside the frame member 41 by FPC or the like.

A manifold that forms a predetermined ink flow path is connected to the surface of the actuator base 20 opposite to the nozzle plate 30 . The manifold includes a supply channel, which is a channel that communicates with the common chamber C3 and the supply channel 133a, and a recovery channel that communicates with the common chamber C3 and with the recovery channel 133b. For example, a circuit board mounted with, for example, a driving IC is provided on the outer surface of the manifold, and the driving IC is electrically connected to the electrodes 24 via FPCs (Flexible Printed Circuits) and wiring patterns.

The nozzle plate 30 is formed in a rectangular plate shape from a resin material such as a polyimide film. A plurality of nozzles 31 are formed through the nozzle plate 30 in the thickness direction. A plurality of nozzles 31 communicate with each pressure chamber C1. In this embodiment, the nozzles 31 are arranged in two rows, and 600 nozzles 31 are arranged in parallel in each row. The nozzle plate 30 is arranged to face the actuator base 20 and covers the groove row 23A on the substrate 21 to close the opening of the second groove 23b and to form the pressure chamber C1 formed by the first groove 23a into the nozzle. 31.

The frame 40 has a rectangular frame shape and includes a frame member 41 forming a rectangular opening 41a in the center. The frame member 41 has a predetermined thickness and is arranged between the actuator base 20 and the nozzle plate 30 to form a common chamber communicating with the first groove 23a of the actuator base 20 arranged in the opening 41a. Form C3.

The inkjet head 1 configured as described above has a plurality of pressure chambers C1 communicating with the nozzles 31 and a plurality of pressure chambers C1 communicating with the nozzles 31 in the openings 41a of the frame member 41 in a state in which the actuator base 20, the nozzle plate 30, and the frame 40 are assembled. , a plurality of air chambers C2 closed by the nozzle plate 30 and the cover wall 27, and a common chamber C3 communicating with the plurality of pressure chambers C1 are formed. The pressure chambers C1 and the air chambers C2 are arranged alternately in the first direction and partitioned by a partition wall portion 25 made of a piezoelectric element.

Next, an inkjet printer 100 having the inkjet head 1 will be described with reference to FIG. FIG. 5 is an explanatory diagram showing the configuration of the inkjet printer 100. As shown in FIG. As shown in FIG. 5, the inkjet printer 100 includes a housing 111, a medium supply section 112, an image forming section 113, a medium discharge section 114, a conveying device 115, and a control section .

The inkjet printer 100 conveys a recording medium, such as paper P, which is an object to be ejected, along a predetermined conveying path A1 from the medium supplying unit 112 through the image forming unit 113 to the medium discharging unit 114, while feeding ink or the like. It is a liquid ejection device that performs an image forming process on a sheet of paper P by ejecting liquid.

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

The support portion 117 includes a conveying belt 118 provided in a loop shape in a predetermined area for image formation, a support plate 119 supporting the conveying belt 118 from the back side, and a plurality of belt rollers 120 provided on the back side of the conveying belt 118 . , provided.

The head unit 130 includes a plurality of inkjet heads 1, a plurality of ink tanks 132 as liquid tanks mounted on each inkjet head 1, a connection flow path 133 connecting the inkjet heads 1 and the ink tanks 132, and a circulation pump 134 that is a circulation unit. The head unit 130 is a circulation type head unit that circulates liquid.

In this embodiment, the ink jet heads 1C, 1M, 1Y, and 1B of four colors of cyan, magenta, yellow, and black are used as the ink jet heads 1, and ink tanks 132C and 132M are used as the ink tanks 132 that respectively contain the inks of these colors. , 132Y, 132B. The ink tank 132 is connected to the inkjet head 1 by a connection channel 133 . The connection channel 133 includes a supply channel 133 a connected to the supply port of the inkjet head 1 and a recovery channel 133 b connected to the discharge port of the inkjet head 1 .

The ink tank 132 is also connected to a negative pressure control device such as a pump (not shown). The negative pressure in the ink tank 132 is controlled by the negative pressure control device corresponding to the head pressure of the ink jet head 1 and the ink tank 132, so that the ink supplied to each nozzle of the ink jet head 1 is formed into a predetermined shape. A meniscus is formed.

The circulation pump 134 is, for example, a liquid feed pump configured by a piezoelectric pump. The circulation pump 134 is provided in the supply channel 133a. The circulation pump 134 is connected to the drive circuit of the controller 116 by wiring. A CPU (Central Processing Unit) 116 a is configured to be able to control a circulation pump 134 . A circulation pump 134 circulates the liquid in a circulation channel including the inkjet head 1 and the ink tank 132 .

The transport device 115 transports the paper P along a transport path A1 from the paper feed cassette 112 a of the medium supply unit 112 to the paper discharge tray 114 a of the medium discharge unit 114 through the image forming unit 113 . The conveying device 115 includes a plurality of guide plate pairs 121a to 121h arranged along the conveying path A1 and a plurality of conveying rollers 122a to 122h.

The control unit 116 includes a CPU 116a as a controller, a ROM (Read Only Memory) for storing various programs, a RAM (Random Access Memory) for temporarily storing various variable data, image data, and the like. and an interface unit for inputting data from and outputting data to the outside.

When the inkjet head 1 and the inkjet printer 100 are driven to eject liquid from the nozzles 31 , the control unit 116 applies a driving voltage via the wiring pattern 26 by the driving circuit. When a potential difference is applied between the electrodes in the pressure chamber C1 driven by voltage application and the electrodes in the air chambers C2 on both sides, the first piezoelectric element 25a and the second piezoelectric element 25b are deformed in opposite directions, and both piezoelectric elements are deformed. The deformation of the element bends and deforms the driving element. For example, first, the pressure chamber C1 to be driven is deformed in the opening direction to make the inside of the pressure chamber C1 have a negative pressure, thereby introducing the ink into the pressure chamber C1. Subsequently, the pressure chamber C<b>1 is deformed in a closing direction to pressurize the inside of the pressure chamber C<b>1 , thereby ejecting an ink droplet from the nozzle 31 .

The operations of the inkjet head 1 and the inkjet printer 100 configured as described above will be described. The control unit 116 detects a print instruction based on, for example, a user's operation input or an external instruction. When the print instruction is detected, the control unit 116 drives the transport device 115 to transport the paper P, and outputs a print signal to the head unit 130 at a predetermined timing, thereby driving the inkjet head 1. do. As an ejection operation, the inkjet head 1 selectively drives the piezoelectric elements in response to an image signal corresponding to image data to eject ink from the nozzles 31 to form an image on the paper P held on the transport belt 118 . .

As the liquid ejecting operation, the CPU 116a deforms the laminated piezoelectric body 22 by applying a driving voltage to the electrodes 24 on the laminated piezoelectric body 22 via the wiring pattern 26 by the driving circuit. For example, by deforming in a direction to increase the volume of the pressure chamber C1 to be driven and creating a negative pressure in the pressure chamber C1, the ink is guided into the pressure chamber C1. On the other hand, an ink droplet is ejected from the nozzle 31 by deforming in a direction in which the volume of the pressure chamber C<b>1 decreases and pressurizing the inside of the pressure chamber C<b>1 . A droplet Id is ejected from a pair of nozzles 31 arranged to face the pressure chamber C1 due to the change in the volume of the pressure chamber C1. Then, the droplets Id are jetted onto the sheet of paper P that is arranged to face them.

According to the inkjet head 1 and the inkjet printer 100 according to the present embodiment, it is possible to provide an inkjet head, an inkjet device, and an inkjet head manufacturing method that can ensure ejection performance and pressure resistance. That is, by biasing the adhesive 50 to the dummy air chamber C2 that does not communicate with the nozzle 31, the required amount of the adhesive 50 can be applied, and pressure resistance can be ensured by ensuring high adhesive strength. At the same time, it is possible to prevent the adhesive 50 from entering the pressure chamber C1 side, thereby avoiding the influence on the liquid ejection performance. Moreover, since it can be realized only by changing the coating position, existing manufacturing equipment and manufacturing processes can be used.

It should be noted that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying constituent elements without departing from the scope of the present invention at the implementation stage.

In the above-described first embodiment, as an example, an example of adjusting the application area in the application process of applying the adhesive 50 to the joint surface 25c was shown, but the present invention is not limited to this. For example, as another embodiment, as shown in FIG. 6, the position of the adhesive is controlled by providing a pressure difference between the first groove 23a and the second groove 23b in the curing step after the application process. good too. Specifically, in the manufacturing process of the inkjet head 1, the bonding process for bonding the actuator base 20 and the nozzle plate 30 includes an application step of applying an adhesive to the bonding surface 25c of the partition wall 25, and a step of applying the adhesive to the bonding surface 25c. It includes a bonding step of bonding the nozzle plate 30 to the actuator base 20 and a curing step of curing the adhesive.

In this embodiment, as the adhesive 50, an epoxy-based adhesive that is effective in ink resistance and that is heated to 80° C. during curing is used. In this embodiment, after the adhesive 50 is applied to the joint surface 25c and the nozzle plate 30 is adhered to the partition wall portion 25 and assembled, the assembled parts are placed in a pressure heating chamber when heating and curing the assembled parts. . That is, by exposing the assembled parts to a high-pressure environment, the pressure in the closed air chamber C2 is made lower than the pressure in the pressure chamber C1 communicating with the outside. Therefore, the adhesive 50 flows toward the lower pressure air chamber C2 until the adhesive 50 is completely hardened, and the position of the adhesive 50 is biased. For example, in the coating process, even when the adhesive is applied to the center of the joint surface 25c of the partition wall 25, the pressure difference can cause the adhesive to be biased. Also in this embodiment, as in the first embodiment, it is possible to prevent the adhesive from entering the first groove 23a, ie, the pressure chamber C1 side, and to ensure pressure resistance and ejection performance. In addition, the pressure difference can be generated between the pressure chamber C1 and the air chamber C2 only by putting the assembly parts into the pressure chamber, and the area of the adhesive can be easily controlled.

Further, in the above-described embodiment, the actuator base 20 having the laminated piezoelectric member 22 made of a piezoelectric member on the substrate 21 was exemplified, but the present invention is not limited to this. For example, the actuator base 20 may be formed using only piezoelectric members without using the substrate 21 . Also, instead of using two piezoelectric members, one piezoelectric member may be used.

Further, the liquid to be ejected is not limited to ink, and liquids other than ink can also be ejected. A liquid ejecting apparatus that ejects other than ink may be, for example, an apparatus that ejects a liquid containing conductive particles for forming a wiring pattern of a printed wiring board.

In addition to the above, the inkjet head 1 may have a structure that ejects ink droplets by deforming a vibration plate, or a structure that ejects ink droplets from nozzles using thermal energy such as a heater.

Although the inkjet head 1 has an example of a configuration in which every other pressure chamber C1 is arranged, the configuration is not limited to this. For example, two or more dummy air chambers C2 may be arranged between the pair of pressure chambers C1, C1. By shifting the position of to the air chamber C2 side, it is possible to maintain the liquid ejection performance of the nozzle while ensuring adhesive strength and pressure resistance.

Further, in the above-described embodiments, an example in which the liquid ejecting apparatus is used in an inkjet recording apparatus is shown, but the present invention is not limited to this. For example, it can be used for 3D printers, industrial manufacturing machines, and medical applications, and can be made smaller, lighter, and less expensive.

According to at least one embodiment described above, it is possible to provide an inkjet head, an inkjet apparatus, and a method for manufacturing an inkjet head that can ensure ejection performance and pressure resistance.

Additionally, while several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

1 (1C, 1M, 1Y, 1B)... Inkjet head 20... Actuator base 21... Substrate 21a... Supply hole 21b... Recovery hole 22... Laminated piezoelectric body 23... Groove 23A... Groove row 23a... First groove 23b Second groove 24 Electrode 25 Partition (wall) 25a First piezoelectric element 25b Second piezoelectric element 25c Joint surface 26 Wiring pattern , 27... cover wall, 30... nozzle plate, 31... nozzle, 40... frame, 41... frame member, 41a... opening, 50... adhesive, 100... inkjet printer, 111... housing, 112... medium supply unit, DESCRIPTION OF SYMBOLS 112a... Paper feed cassette, 113... Image formation part, 114... Medium discharge part, 114a... Paper discharge tray, 115... Conveying apparatus, 116... Control part, 116a... CPU, 117... Support part, 118... Conveying belt, 119... Support plate 120 Belt roller 121a to 121h Guide plate pair 122a to 122h Transport roller 130 Head unit 132 Ink tank 133 Connection channel 133a Supply channel 133b Recovery flow Path 134 Circulation pump A1 Transfer path C1 Pressure chamber C2 Air chamber C3 Common chamber.

Claims (5)

a nozzle plate having a plurality of nozzles;
a plurality of wall portions having a joint surface to be joined to the nozzle plate; a plurality of first grooves arranged on one side of the wall portion and forming pressure chambers communicating with the plurality of nozzles; an actuator base having a plurality of second grooves arranged on the other side;
The nozzle plate and the actuator base are joined with an adhesive between the joining surfaces of the plurality of wall portions and the nozzle plate, and the wall portions of a majority of the plurality of wall portions are An inkjet head in which an adhesive is distributed more toward the second groove side than toward the first groove side. The inkjet head according to claim 1;
and a conveying device that conveys a recording medium along a predetermined conveying path. a nozzle plate having nozzles; a wall portion having a joint surface joined to the nozzle plate; a first groove disposed on one side of the wall portion and communicating with the nozzle; and an actuator base having a plurality of second grooves, respectively, on the joint surface of the wall portion via an adhesive that is arranged more toward the second groove side than the first groove side. How the head is made. 4. The method of manufacturing an inkjet head according to claim 3, wherein when the adhesive is applied to the wall portion or the nozzle plate, the application area or application amount is biased toward the second groove side. In a state in which the nozzle plate and the actuator base are attached with the adhesive disposed between the wall portion and the nozzle plate, the pressure in the first groove is applied to the pressure in the second groove. 4. The method of manufacturing an inkjet head according to claim 3, wherein the adhesive is biased toward the second groove side by increasing the height of the adhesive.

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