Liquid ejection head and recording apparatus

Abstract

To provide a liquid discharge head which is excellent in impact resistance, and a recording device.SOLUTION: A liquid discharge head has a flow channel member, a reservoir, and a reinforcement plate. The flow channel member has nozzles for discharging liquid droplets, and pressurization chambers connected to the nozzles. The reservoir supplies a liquid to the pressurization chambers. The reservoir has a first part where a plurality of plate-like members are stacked, and a second part with a width in a direction perpendicular to the stacking direction of the plate-like member larger than that of the first part, in this order from the downstream side. The reinforcement plate has a main surface positioned on the side face of the first part, and an end face positioned on a step surface of the first part and the second part.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The disclosed embodiments relate to a liquid ejection head and a recording apparatus. [Background technology]

[0002] 2. Description of the Related Art Known printing devices include inkjet printers and inkjet plotters that use an inkjet recording method. Such inkjet printing devices are equipped with a liquid ejection head for ejecting liquid droplets.

[0003] Patent Document 1 describes a liquid ejection head having a flow path member with a plurality of nozzles and a reservoir that supplies liquid to the flow path member, in which the reservoir is made of a laminate of a plurality of plate-like members. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-206945 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned prior art has room for further improvement in terms of improving impact resistance.

[0006] One aspect of the embodiment has been made in view of the above, and aims to provide a liquid ejection head and a recording apparatus that are excellent in impact resistance. [Means for solving the problem]

[0007] A liquid ejection head according to one aspect of the embodiment includes a flow path member, a reservoir, and a reinforcing plate. The flow path member includes a nozzle for ejecting droplets and a pressure chamber connected to the nozzle. The reservoir supplies liquid to the pressure chamber. The reservoir includes, in order from the downstream side, a first portion in which a plurality of plate-like members are stacked, and a second portion whose width in a direction perpendicular to the stacking direction of the plate-like members is greater than that of the first portion. The reinforcing plate has a main surface located on a side surface of the first portion and an end face located on a step surface between the first portion and the second portion. [Effects of the Invention]

[0008] According to one aspect of the embodiment, it is possible to provide a liquid ejection head and a recording apparatus that are excellent in impact resistance. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic side view of a printer according to an embodiment. [Figure 2] FIG. 2 is a schematic plan view of the printer according to the embodiment. [Figure 3] FIG. 3 is a schematic exploded perspective view of the liquid ejection head according to the embodiment. [Figure 4] FIG. 4 is an enlarged plan view of the head main body according to the embodiment. [Figure 5] FIG. 5 is an enlarged view of the area surrounded by the dashed line shown in FIG. [Figure 6] 6 is a cross-sectional view taken along the line VI-VI in FIG. [Figure 7] FIG. 7 is a schematic side view of the head main body according to the embodiment as viewed along the longitudinal direction. [Figure 8] FIG. 8 is a schematic side view of the head main body according to the embodiment as viewed along the short side direction. [Figure 9] FIG. 9 is a schematic cross-sectional view taken along the line IX-IX in FIG. [Figure 10] FIG. 10 is a schematic enlarged view of the region X shown in FIG. [Figure 11]FIG. 11 is an explanatory diagram of a method for attaching the reinforcing plate. [Figure 12] FIG. 12 is an explanatory diagram of a method for attaching the reinforcing plate. [Figure 13] FIG. 13 is an explanatory diagram of a method for attaching the reinforcing plate. [Figure 14] FIG. 14 is a schematic side view of the head main body according to the first modified example, viewed along the longitudinal direction. [Figure 15] FIG. 15 is a schematic side view of a head main body according to a second modified example, viewed along the longitudinal direction. [Figure 16] FIG. 16 is a schematic enlarged view of region XVI shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings, with reference to the accompanying drawings. It should be noted that the present invention is not limited to the following embodiments.

[0011] 2. Description of the Related Art Known printing devices include inkjet printers and inkjet plotters that use an inkjet recording method. These inkjet printing devices are equipped with a liquid ejection head for ejecting liquid droplets.

[0012] In such a liquid ejection head, for example, if a jam occurs, a recording medium may come into contact with the nozzle surface of the liquid ejection head. If the contact of the recording medium causes an impact on the liquid ejection head, the multiple plate-like members that make up the reservoir may peel off. Furthermore, if the multiple plate-like members peel off, liquid may leak from the gaps between the plate-like members. Note that the peeling location is not limited to the reservoir. For example, the reservoir may peel off from the flow path member.

[0013] For these reasons, there is a demand for a liquid ejection head and a recording apparatus that are highly shock-resistant.

[0014] <Printer configuration> First, an overview of a printer 1, which is an example of a recording apparatus according to an embodiment, will be described with reference to Figures 1 and 2. Figure 1 is a schematic side view of the printer 1 according to an embodiment. Figure 2 is a schematic plan view of the printer 1 according to an embodiment. The printer 1 according to an embodiment is, for example, a color inkjet printer.

[0015] 1, the printer 1 includes a paper feed roller 2, a guide roller 3, a coater 4, a head case 5, a plurality of transport rollers 6, a plurality of frames 7, a plurality of liquid ejection heads 8, a transport roller 9, a dryer 10, a transport roller 11, a sensor unit 12, and a recovery roller 13. The transport roller 6 is an example of a transport unit.

[0016] Furthermore, the printer 1 has a control unit 14 that controls each part of the printer 1. The control unit 14 controls the operations of the paper feed roller 2, the guide roller 3, the coater 4, the head case 5, the plurality of conveying rollers 6, the plurality of frames 7, the plurality of liquid ejection heads 8, the conveying roller 9, the dryer 10, the conveying roller 11, the sensor unit 12, and the recovery roller 13.

[0017] The printer 1 records images and characters on the recording medium P by causing droplets to land on the recording medium P. The recording medium P is, for example, paper. However, the recording medium P is not limited to this, and may be cloth or the like. Before use, the recording medium P is wound around a paper feed roller 2. The printer 1 transports the recording medium P wound around the paper feed roller 2 into the inside of a head case 5 via a guide roller 3 and a coater 4.

[0018] The coater 4 applies the coating agent uniformly to the recording medium P. This allows the surface of the recording medium P to be treated, thereby improving the printing quality of the printer 1.

[0019] The head case 5 houses a plurality of transport rollers 6, a plurality of frames 7, and a plurality of liquid ejection heads 8. Inside the head case 5, a space is formed that is isolated from the outside except for a portion that is connected to the outside, such as a portion where the recording medium P enters and exits.

[0020] At least one of control factors such as temperature, humidity, and air pressure of the internal space of the head case 5 is controlled by the control unit 14 as necessary. The transport roller 6 transports the recording medium P inside the head case 5 to the vicinity of the liquid ejection head 8.

[0021] The frame 7 is a rectangular flat plate, and is positioned above and in close proximity to the recording medium P being transported by the transport rollers 6. As shown in Fig. 2, the frame 7 is positioned so that its longitudinal direction is perpendicular to the transport direction of the recording medium P. Inside the head case 5, a plurality of (for example, four) frames 7 are positioned at predetermined intervals along the transport direction of the recording medium P.

[0022] In the following description, the transport direction of the recording medium P may be referred to as the "sub-scanning direction," and the direction perpendicular to the sub-scanning direction and parallel to the recording medium P may be referred to as the "main scanning direction."

[0023] A liquid, such as ink, is supplied from a liquid tank (not shown) to the liquid ejection head 8. The liquid ejection head 8 ejects the liquid supplied from the liquid tank.

[0024] The control unit 14 controls the liquid ejection head 8 based on data such as images and characters, and ejects liquid toward the recording medium P. The distance between the liquid ejection head 8 and the recording medium P is, for example, about 0.5 to 20 mm.

[0025] The liquid ejection head 8 is fixed to the frame 7. The liquid ejection head 8 is positioned so that its longitudinal direction is perpendicular to the direction in which the recording medium P is transported.

[0026] That is, the printer 1 according to the embodiment is a so-called line printer in which the liquid ejection head 8 is fixed inside the printer 1. Note that the printer 1 according to the embodiment is not limited to a line printer, and may also be a so-called serial printer.

[0027] A serial printer is a printer that alternates between recording by moving the liquid ejection head 8 back and forth in a direction that intersects the transport direction of the recording medium P, for example, in a direction that is approximately perpendicular to the direction of transport, and transporting the recording medium P.

[0028] As shown in Fig. 2, a plurality of (for example, five) liquid ejection heads 8 are fixed to one frame 7. Fig. 2 shows an example in which three liquid ejection heads 8 are positioned in front and two in the rear in the transport direction of the recording medium P, and the liquid ejection heads 8 are positioned so that the centers of the respective liquid ejection heads 8 do not overlap in the transport direction of the recording medium P.

[0029] A head group 8A is made up of multiple liquid ejection heads 8 positioned on one frame 7. The four head groups 8A are positioned along the transport direction of the recording medium P. The same color ink is supplied to the liquid ejection heads 8 belonging to the same head group 8A. This allows the printer 1 to print with four colors of ink using the four head groups 8A.

[0030] The colors of ink ejected from each head group 8A are, for example, magenta (M), yellow (Y), cyan (C), and black (K). The control unit 14 controls each head group 8A to eject ink of multiple colors onto the recording medium P, thereby printing a color image on the recording medium P.

[0031] In order to perform surface treatment on the recording medium P, a coating agent may be ejected onto the recording medium P from the liquid ejection head 8.

[0032] Furthermore, the number of liquid ejection heads 8 included in one head group 8A and the number of head groups 8A mounted on the printer 1 can be changed as appropriate depending on the object to be printed and the printing conditions. For example, if a single color is printed on the recording medium P and the printing range is to be printed with one liquid ejection head 8, the number of liquid ejection heads 8 mounted on the printer 1 may be one.

[0033] The recording medium P that has been printed inside the head case 5 is transported to the outside of the head case 5 by transport rollers 9 and passes through the inside of a dryer 10. The dryer 10 dries the recording medium P that has been printed. The recording medium P that has been dried in the dryer 10 is transported by transport rollers 11 and collected by a collection roller 13.

[0034] In the printer 1, by drying the recording medium P with the dryer 10, it is possible to prevent the recording media P that are wound up in a stack on the collection roller 13 from adhering to each other and preventing the undried liquid from rubbing against each other.

[0035] The sensor unit 12 is composed of a position sensor, a speed sensor, a temperature sensor, etc. The control unit 14 can determine the state of each part of the printer 1 based on information from the sensor unit 12 and control each part of the printer 1.

[0036] The printer 1 described so far has been shown to use a recording medium P as the printing object (i.e., recording medium), but the printing object in printer 1 is not limited to the recording medium P, and the printing object may also be a roll of cloth, etc.

[0037] Furthermore, the printer 1 may transport the recording medium P on a conveyor belt instead of directly transporting the recording medium P. By using a conveyor belt, the printer 1 can print on sheets of paper, cut pieces of cloth, wood, tiles, and the like.

[0038] The printer 1 may also print wiring patterns for electronic devices by ejecting a liquid containing conductive particles from the liquid ejection head 8. The printer 1 may also produce chemicals by ejecting a predetermined amount of liquid chemicals or liquid containing chemicals from the liquid ejection head 8 toward a reaction vessel or the like.

[0039] <Configuration of liquid ejection head> Next, the configuration of the liquid ejection head 8 according to this embodiment will be described with reference to Fig. 3. Fig. 3 is a schematic exploded perspective view of the liquid ejection head 8 according to this embodiment.

[0040] The liquid ejection head 8 has a head main body 20, a wiring section 30, a housing 40, and a pair of heat sinks 45. The head main body 20 has a flow path member 21, a piezoelectric actuator substrate 22 (see FIG. 4), and a reservoir 23.

[0041] In the following description, for convenience, the direction in which the head main body 20 is provided in the liquid ejection head 8 may be referred to as "downward," and the direction in which the housing 40 is provided relative to the head main body 20 may be referred to as "upward."

[0042] The flow path member 21 of the head main body 20 has a substantially flat plate shape and has a first surface 21a (see FIG. 6) which is one main surface, and a second surface 21b (see FIG. 6) located on the opposite side of the first surface 21a. The first surface 21a has an opening (not shown), and liquid is supplied into the flow path member 21 from a reservoir 23 (described later) through the opening.

[0043] A plurality of ejection holes 63 (see FIG. 6) that eject liquid onto the recording medium P are located on the second surface 21b. In other words, the second surface 21b is the nozzle surface of the head main body 20. The flow path member 21 has a flow path therein that allows liquid to flow from the first surface 21a to the second surface 21b. The ejection holes 63 are an example of a nozzle.

[0044] The piezoelectric actuator substrate 22 is located on the first surface 21a of the flow path member 21. The piezoelectric actuator substrate 22 has a plurality of displacement elements 70 (see FIG. 6). The flexible substrate 31 of the wiring section 30 is electrically connected to the piezoelectric actuator substrate 22. The configuration of the piezoelectric actuator substrate 22 will be described later with reference to FIGS. 4 to 6.

[0045] A reservoir 23 is disposed on the piezoelectric actuator substrate 22. Specifically, the reservoir 23 is located on the first surface 21a of the flow path member 21 so as to cover the piezoelectric actuator substrate 22.

[0046] The reservoir 23 supplies liquid to a pressurizing chamber 62 (described later) of the flow path member 21. Specifically, the reservoir 23 has openings 23a at both ends in the longitudinal direction. The reservoir 23 has a flow path therein, and liquid is supplied from the outside through the openings 23a. The reservoir 23 has the function of supplying liquid to the pressurizing chamber 62 of the flow path member 21 and the function of storing the supplied liquid.

[0047] The wiring section 30 has a flexible substrate 31, a head substrate 32, a driver IC 33, a pressing member 34, and an elastic member 35. The flexible substrate 31 has a function of transmitting a predetermined signal sent from the outside to the head main body 20. As shown in FIG. 3, the liquid ejection head 8 according to the embodiment has two flexible substrates 31.

[0048] One end of the flexible substrate 31 is electrically connected to the piezoelectric actuator substrate 22 of the head body 20. The other end of the flexible substrate 31 is drawn upward so as to pass through the opening 23b of the reservoir 23, and is electrically connected to the head substrate 32.

[0049] This allows electrical connection between the piezoelectric actuator substrate 22 of the head body 20 and the outside. The flexible substrate 31 is, for example, a film-like substrate (COF) made of polyimide, and a driver IC 33 and the like are mounted on the substrate.

[0050] The head substrate 32 is located above the head main body 20. The head substrate 32 has the function of distributing signals to the driver IC 33. The driver IC 33 is provided on one main surface of the flexible substrate 31. The driver IC 33 drives the piezoelectric actuator substrate 22 of the head main body 20 based on signals sent from the control unit 14 (see FIG. 1). In this way, the driver IC 33 drives the liquid ejection head 8.

[0051] The pressing member 34 has a substantially U-shape in cross section, and presses the driver IC 33 on the flexible substrate 31 from the inside toward the heat sink 45. As a result, in this embodiment, heat generated when the driver IC 33 is driven can be efficiently dissipated to the heat sink 45 on the outside.

[0052] The elastic member 35 is positioned so as to contact the outer wall of the pressing portion (not shown) of the pressing member 34. By providing such an elastic member 35, it is possible to reduce the possibility that the pressing member 34 will damage the flexible substrate 31 when pressing the driver IC 33.

[0053] The elastic member 35 is made of, for example, a double-sided foam tape. Also, by using, for example, a non-silicon heat conductive sheet as the elastic member 35, it is possible to improve the heat dissipation of the driver IC 33. However, the elastic member 35 is not necessarily required.

[0054] The housing 40 is disposed on the head main body 20 so as to cover the wiring portion 30. This allows the housing 40 to seal the wiring portion 30. The housing 40 is made of, for example, resin or metal.

[0055] The housing 40 has a box shape that extends long in the main scanning direction, and has a first opening 40a and a second opening 40b on a pair of side surfaces that face each other in the main scanning direction. The housing 40 also has a third opening 40c on its bottom surface and a fourth opening 40d on its top surface.

[0056] One side of the heat sink 45 is positioned in the first opening 40a so as to cover the first opening 40a, and the other side of the heat sink 45 is positioned in the second opening 40b so as to cover the second opening 40b.

[0057] The heat sink 45 is provided to extend in the main scanning direction and is made of a highly heat-dissipating metal, alloy, etc. The heat sink 45 is provided to be in contact with the driver IC 33 and dissipates heat generated by the driver IC 33.

[0058] The pair of heat sinks 45 are each fixed to the housing 40 with screws (not shown). Therefore, the housing 40 to which the heat sinks 45 are fixed has a box shape in which the first opening 40a and the second opening 40b are closed and the third opening 40c and the fourth opening 40d are open.

[0059] The third opening 40c is positioned so as to face the reservoir 23. The flexible substrate 31 and the pressing member 34 are inserted into the third opening 40c.

[0060] The fourth opening 40d is provided for inserting a connector (not shown) provided on the head substrate 32. If the space between the connector and the fourth opening 40d is sealed with resin or the like, it becomes difficult for liquid, dust, and the like to enter the inside of the housing 40.

[0061] The housing 40 also has a heat insulating portion 40e. The heat insulating portion 40e is disposed adjacent to the first opening 40a and the second opening 40b, and is provided so as to protrude outward from the side surface of the housing 40 along the main scanning direction.

[0062] The heat insulating portion 40e is formed to extend in the main scanning direction. That is, the heat insulating portion 40e is located between the heat sink 45 and the head main body 20. By providing the heat insulating portion 40e in the housing 40 in this way, heat generated in the driver IC 33 is less likely to be transmitted to the head main body 20 via the heat sink 45.

[0063] It should be noted that the configuration of the liquid ejection head 8 shown in FIG. 3 is merely an example, and the configuration of the liquid ejection head 8 is not limited to the configuration shown in FIG.

[0064] <Head body configuration> Next, the configuration of the head main body 20 according to this embodiment will be described with reference to Figs. 4 to 6. Fig. 4 is an enlarged plan view of the head main body 20 according to this embodiment. Fig. 5 is an enlarged view of an area V surrounded by a dashed line shown in Fig. 4. Fig. 6 is a cross-sectional view taken along the line VI-VI shown in Fig. 4.

[0065] 4, the head main body 20 has a flow path member 21 and a piezoelectric actuator substrate 22. The flow path member 21 has a supply manifold 61, a plurality of pressure chambers 62, and a plurality of discharge holes 63.

[0066] The plurality of pressurizing chambers 62 are connected to the supply manifold 61. The plurality of discharge holes 63 are connected to the plurality of pressurizing chambers 62, respectively.

[0067] The pressurizing chamber 62 opens to a first surface 21a (see FIG. 6) of the flow path member 21. The first surface 21a of the flow path member 21 has an opening 61a that connects to the supply manifold 61. Liquid is supplied from the reservoir 23 (see FIG. 2) to the inside of the flow path member 21 through the opening 61a.

[0068] 4, the head main body 20 has four supply manifolds 61 inside the flow path member 21. The supply manifolds 61 have an elongated shape extending along the longitudinal direction of the flow path member 21 (i.e., the main scanning direction), and openings 61a of the supply manifolds 61 are formed on the first surface 21a of the flow path member 21 at both ends thereof.

[0069] A plurality of pressure chambers 62 are formed in the flow path member 21, spreading two-dimensionally. As shown in Fig. 5, the pressure chambers 62 are hollow regions having, for example, a generally diamond-shaped planar shape with rounded corners. The shape of the pressure chambers 62 is not limited to the example shown in the figure. The pressure chambers 62 open to the first surface 21a of the flow path member 21, and are closed by bonding the piezoelectric actuator substrate 22 to the first surface 21a.

[0070] The pressure chambers 62 form pressure chamber rows arranged in the longitudinal direction. The pressure chambers 62 in a pressure chamber row are arranged in a staggered pattern between two adjacent pressure chamber rows. Four pressure chamber rows connected to one supply manifold 61 form one pressure chamber group. In the example of FIG. 4, the flow path member 21 has four such pressure chamber groups.

[0071] Furthermore, the relative arrangement of the pressure chambers 62 within each pressure chamber group is the same, and the pressure chamber groups are arranged with a slight shift in the longitudinal direction.

[0072] The discharge holes 63 are arranged at positions that avoid an area of ​​the flow path member 21 that faces the supply manifold 61. In other words, when the flow path member 21 is seen through from the first surface 21a side, the discharge holes 63 do not overlap with the supply manifold 61.

[0073] Furthermore, in plan view, the discharge holes 63 are arranged so as to fit within the mounting area of ​​the piezoelectric actuator substrate 22. Such discharge holes 63 as a group occupy an area of ​​approximately the same size and shape as the piezoelectric actuator substrate 22.

[0074] In the liquid ejection head 8, the driver IC 33 displaces the displacement elements 70 (see FIG. 6) of the piezoelectric actuator substrate 22 based on a signal sent from the control unit 14 (see FIG. 1). This causes the pressure chamber 62 to be pressurized, and the liquid in the pressure chamber 62 is ejected from the ejection hole 63.

[0075] 6, the flow path member 21 has a laminated structure in which multiple plates are stacked. For example, the flow path member 21 has, in order from the top surface of the flow path member 21, a cavity plate 21A, a base plate 21B, an aperture plate 21C, a supply plate 21D, manifold plates 21E, 21F, and 21G, a cover plate 21H, and a nozzle plate 21I.

[0076] A large number of holes are formed in the plate. The thickness of the plate is approximately 10 μm to 300 μm. This allows for high accuracy in forming the holes. The plates are aligned and stacked so that the holes communicate with each other to form predetermined flow paths.

[0077] In the flow path member 21, the supply manifold 61 and the discharge holes 63 are connected by individual flow paths 64. The supply manifold 61 is located on the second surface 21b side inside the flow path member 21, and the discharge holes 63 are located on the second surface 21b of the flow path member 21.

[0078] The individual flow path 64 has a pressurizing chamber 62 and an individual supply flow path 65. The pressurizing chamber 62 is located on the first surface 21a of the flow path member 21, and the individual supply flow path 65 is a flow path that connects the supply manifold 61 and the pressurizing chamber 62.

[0079] Furthermore, the individual supply flow path 65 includes a restriction 66 that is narrower than the other portions. The restriction 66 has a high flow path resistance because it is narrower than the other portions of the individual supply flow path 65. When the flow path resistance of the restriction 66 is high in this way, the pressure generated in the pressurizing chamber 62 is less likely to escape to the supply manifold 61.

[0080] The piezoelectric actuator substrate 22 has piezoelectric ceramic layers 22A and 22B, a common electrode 71, individual electrodes 72, a connection electrode 73, a dummy connection electrode 74, and a surface electrode 75 (see FIG. 4). The piezoelectric ceramic layer 22B, the common electrode 71, the piezoelectric ceramic layer 22A, and the individual electrodes 72 are stacked in this order from the bottom up, i.e., from the flow path member 21 side.

[0081] The piezoelectric ceramic layers 22A and 22B each extend on the first surface 21a of the flow path member 21 so as to straddle the multiple pressure chambers 62. The piezoelectric ceramic layers 22A and 22B each have a thickness of approximately 20 μm. The piezoelectric ceramic layers 22A and 22B are made of, for example, a ferroelectric ceramic material such as lead zirconate titanate (PZT).

[0082] The common electrode 71 is formed over substantially the entire surface in the plane direction in the region between the piezoelectric ceramic layer 22A and the piezoelectric ceramic layer 22B. In other words, the common electrode 71 overlaps with all of the pressure chambers 62 in the region facing the piezoelectric actuator substrate 22.

[0083] The common electrode 71 has a thickness of about 2 μm and is made of, for example, a metal material such as Ag—Pd.

[0084] The individual electrodes 72 include a main electrode 72a and an extraction electrode 72b. The main electrode 72a is located on the piezoelectric ceramic layer 22A in an area facing the pressure chamber 62. The main electrode 72a is slightly smaller than the pressure chamber 62 and has a shape that is approximately similar to the pressure chamber 62.

[0085] The extraction electrode 72b is extracted from the main electrode 72a to the outside of the region facing the pressure chamber 62. The individual electrodes 72 are made of, for example, a metal material such as an Au-based material.

[0086] The connection electrode 73 is located on the extraction electrode 72b and is formed in a convex shape with a thickness of about 15 μm. The connection electrode 73 is electrically connected to an electrode provided on the flexible substrate 31 (see FIG. 3). The connection electrode 73 is made of, for example, silver-palladium containing glass frit.

[0087] The dummy connection electrodes 74 are located on the piezoelectric ceramic layer 22B so as not to overlap with various electrodes such as the individual electrodes 72. The dummy connection electrodes 74 connect the piezoelectric actuator substrate 22 and the flexible substrate 31, increasing the connection strength.

[0088] Furthermore, the dummy connection electrodes 74 stabilize the electrical connection by uniformly distributing the contact positions between the piezoelectric actuator substrates 22. The dummy connection electrodes 74 are preferably made of the same material as the connection electrodes 73, and are preferably formed in the same process as the connection electrodes 73.

[0089] 4 is formed on the piezoelectric ceramic layer 22B at a position that avoids the individual electrodes 72. The surface electrode 75 is connected to the common electrode 71 through a via hole formed in the piezoelectric ceramic layer 22A.

[0090] As a result, the surface electrode 75 is grounded and maintained at the ground potential. The surface electrode 75 is preferably made of the same material as the individual electrodes 72 and is preferably formed in the same process as the individual electrodes 72.

[0091] In order to individually control the potential of the individual electrodes 72, each individual electrode is electrically connected to the control unit 14 (see FIG. 1) via the flexible substrate 31 and wiring. When the individual electrodes 72 and the common electrode 71 are set to different potentials and an electric field is applied in the polarization direction of the piezoelectric ceramic layer 22A, the portion of the piezoelectric ceramic layer 22A to which the electric field is applied operates as an active portion that is distorted by the piezoelectric effect.

[0092] That is, in the piezoelectric actuator substrate 22, the individual electrodes 72, the piezoelectric ceramic layer 22A, and the portions of the common electrode 71 that face the pressure chambers 62 function as displacement elements .

[0093] When the displacement element 70 undergoes unimorph deformation, the pressure chamber 62 is pressed, and droplets are ejected from the ejection hole 63 .

[0094] Here, the driving procedure of the liquid ejection head 8 according to the embodiment will be described. The individual electrodes 72 are set in advance to a higher potential (hereinafter referred to as "high potential") than the common electrode 71. Then, each time an ejection request is made, the individual electrodes 72 are temporarily set to the same potential as the common electrode 71 (hereinafter referred to as "low potential"), and then are set to the high potential again at a predetermined timing.

[0095] As a result, when the individual electrode 72 becomes low potential, the piezoelectric ceramic layers 22A, 22B return to their original shapes, and the volume of the pressure chamber 62 increases from the initial state, i.e., the state of high potential. At this time, a negative pressure is applied within the pressure chamber 62, so that the liquid within the supply manifold 61 is sucked into the pressure chamber 62.

[0096] Thereafter, when the individual electrode 72 is again set to a high potential, the piezoelectric ceramic layers 22A and 22B deform so as to convexly protrude toward the pressure chamber 62. In other words, the volume of the pressure chamber 62 decreases, and the pressure inside the pressure chamber 62 becomes positive. This increases the pressure of the liquid inside the pressure chamber 62, and droplets are ejected from the ejection holes 63.

[0097] That is, the control unit 14 uses the driver IC 33 to supply a drive signal including a pulse based on a high potential to the individual electrode 72 in order to eject droplets from the ejection hole 63. The pulse width may be set to AL (Acoustic Length), which is the time length for a pressure wave to propagate from the restriction 66 to the ejection hole 63.

[0098] As a result, when the pressure inside the pressure chamber 62 changes from a negative pressure state to a positive pressure state, the two pressures are combined, and droplets can be ejected with a stronger pressure.

[0099] In gradation printing, gradation is expressed by the number of droplets continuously ejected from the ejection holes 63, i.e., the amount (volume) of droplets adjusted by the number of liquid ejections. Therefore, liquid is ejected continuously from the ejection holes 63 corresponding to the specified gradation expression a number of times corresponding to the specified dot region.

[0100] <Reinforcing plate> The head main body 20 further includes a reinforcing plate. The configuration of the reinforcing plate will be described with reference to Figs. 7 to 10. Fig. 7 is a schematic side view of the head main body 20 according to the embodiment as seen along the longitudinal direction. Fig. 8 is a schematic side view of the head main body 20 according to the embodiment as seen along the lateral direction. Fig. 9 is a schematic cross-sectional view taken along the arrows IX-IX shown in Fig. 8. Fig. 10 is a schematic enlarged view of region X shown in Fig. 7.

[0101] Prior to describing the reinforcing plate, the specific configuration of the reservoir 23 will be described with reference to FIGS. 7 and 8. As shown in FIGS. 7 and 8, the reservoir 23 has a plurality of plate-like members 231 to 233. The plurality of plate-like members 231 to 233 are stacked in the order of plate-like member 231, plate-like member 232, and plate-like member 233, starting from the downstream side. Each of the plate-like members 231 to 233 has a shape that is elongated in the main scanning direction. By stacking the plate-like members 231 to 233, the reservoir 23 is formed with flow paths such as an introduction path and branch paths for liquid (flow path 238a, described later), a recessed portion in which the piezoelectric actuator substrate 22 is housed (cavity 237, described later), and the like.

[0102] The shapes of the plate-like members 231 and 232 are rectangular in side view. A side view refers to a viewpoint parallel to the second surface 21b (nozzle surface) of the head main body 20. In contrast, the plate-like member 233 has a shape like two overlapping rectangles of different sizes.

[0103] Specifically, the plate-shaped member 233 has, in order from the downstream side, a narrow portion 233a and a wide portion 233b. The narrow portion 233a has the same horizontal width as the plate-shaped member 231 and the narrow portion 233a, specifically, a width W1 in the sub-scanning direction and a width W3 in the main scanning direction. The wide portion 233b has a larger width in the main scanning direction and a larger width in the sub-scanning direction than the narrow portion 233a. Specifically, the width W2 in the main scanning direction of the wide portion 233b is larger than the width W1 in the main scanning direction of the narrow portion 233a. Furthermore, the width W4 in the sub-scanning direction of the wide portion 233b is larger than the width W2 in the sub-scanning direction of the narrow portion 233a.

[0104] In this way, reservoir 23 is a laminated body formed by stacking a plurality of plate-like members 231 to 233. From another perspective, reservoir 23 has, in order from the downstream side (the second surface 21b side), a first region 23A formed by stacking a plurality of plate-like members (here, plate-like members 231, 232 and narrow portion 233a of plate-like member 233), and a second region 23B (here, wide portion 233b of plate-like member 233) whose width in a direction perpendicular to the stacking direction of the plate-like members is larger than that of the first region.

[0105] The reservoir 23 has a step surface 236 between the first portion 23A and the second portion 23B. The step surfaces 236 are located on both sides of the reservoir 23 in the longitudinal direction and on both sides of the reservoir 23 in the lateral direction.

[0106] Here, an example has been shown in which the narrow portion 233a and the wide portion 233b are integral and form a single plate-like member 233, but the narrow portion 233a and the wide portion 233b may each be separate plate-like members. Also, here, an example has been shown in which the reservoir 23 has three plate-like members 231 to 233, but the reservoir 23 may have at least two or more plate-like members. For example, the reservoir 23 may have four or more plate-like members.

[0107] As shown in FIGS. 7 to 10 , the head main body 20 has a plurality of (here, two) reinforcing plates 25. The reinforcing plates 25 are plate-shaped members. A main surface 250 of the reinforcing plate 25 is located on a side surface 235 of the first portion 23A of the reservoir 23. More specifically, the main surface 250 of the reinforcing plate 25 is located across the side surface 235 of the first portion 23A and the side surface 215 of the flow path member 21. The side surface 235 of the first portion 23A is specifically the side surface of the plate-shaped member 231, the side surface of the plate-shaped member 232, and the side surface of the narrow portion 233a. Note that the side surface here refers to a surface that is perpendicular to the second surface 21b of the flow path member 21.

[0108] The side surfaces 215, 235 on which the reinforcing plate 25 is located are the side surfaces of the first portion 23A and the flow path member 21 that include the long sides of the first portion 23A and the flow path member 21. A main surface 250 of the reinforcing plate 25 extends along the long sides of the first portion 23A and the flow path member 21.

[0109] 9, part of the long side of the first portion 23A is a thin portion 239. Specifically, the first portion 23A has a hollow portion 237. The hollow portion 237 functions as a storage space for the piezoelectric actuator substrate 22. The hollow portion 237 penetrates the plate-like members 231, 232 and the narrow portion 233a of the plate-like member 233, and extends along the longitudinal direction (main scanning direction) of the first portion 23A.

[0110] A thick portion 238 of the first portion 23A is located on the side of the hollow portion 237 in the longitudinal direction (main scanning direction) of the reservoir 23. A flow path 238a connected to the flow path member 21 is located in the thick portion 238. On the other hand, a thin portion 239 that is thinner than the thick portion 238 is located on the side of the hollow portion 237 in the lateral direction (sub-scanning direction) of the reservoir 23. The reinforcing plate 25 is located in the thin portion 239. That is, the reinforcing plate 25 reinforces the thin portion 239 of the first portion 23A.

[0111] The width of the reinforcing plate 25 in the longitudinal direction (main scanning direction) of the reservoir 23 may be the same as, for example, the width W5 of the thin portion 239 in the main scanning direction. However, the present invention is not limited to this. The width of the reinforcing plate 25 in the longitudinal direction (main scanning direction) of the reservoir 23 may be shorter than the width W3 of the first portion 23A in the main scanning direction and longer than the width W5 of the thin portion 239 in the main scanning direction. Furthermore, the width of the reinforcing plate 25 in the longitudinal direction (main scanning direction) of the reservoir 23 may be shorter than the width W5 of the thin portion 239 in the main scanning direction. In this case, the reinforcing plate 25 only needs to be located at least in the center of the thin portion 239, which is likely to be subjected to large stress. The center of the thin portion 239 is, for example, the center when the thin portion 239 is divided into three in the main scanning direction.

[0112] The reinforcing plate 25 is bonded to the reservoir 23 and the side surfaces including the long sides of the first portion 23A via an adhesive 100. The adhesive 100 is located between the main surface 250 of the reinforcing plate 25 and the side surface 235 of the first portion 23A. The adhesive 100 may be, for example, an epoxy-based thermosetting resin.

[0113] The adhesive 100 may be the same as the adhesive used to bond the plate-like members 231-233 of the reservoir 23 together, the adhesive used to bond the plates 21A-21I of the flow path member 21 together, and the adhesive used to bond the flow path member 21 and the reservoir 23. However, without being limited thereto, the adhesive 100 may be different from the adhesive used to bond the plate-like members 231-233 together, the adhesive used to bond the plates 21A-21I of the flow path member 21 together, and the adhesive used to bond the flow path member 21 and the reservoir 23. This point will be described later.

[0114] An upper end surface 251 of the reinforcing plate 25 is located on a step surface 236 between the first portion 23A and the second portion 23B. Specifically, the reinforcing plate 25 is joined to a side surface 235 of the first portion 23A and a side surface 215 of the flow path member 21 in a state of contact with the step surface 236, in other words, in a state of being abutted against the step surface 236.

[0115] As described above, in the liquid ejection head 8 according to the embodiment, the reinforcing plate 25 is located on the side surface 235 of the first portion 23A. The reinforcing plate 25 is located across the plurality of plate-like members 231 to 233 that make up the reservoir 23. Therefore, in the liquid ejection head 8 according to the embodiment, even if an impact is applied to the head main body 20 due to contact with the recording medium P, the plurality of plate-like members 231 to 233 that make up the reservoir 23 are unlikely to peel off.

[0116] Furthermore, in the liquid ejection head 8 according to the embodiment, the upper end surface 251 of the reinforcing plate 25 is in a state of abutting against the step surface 236 between the first portion 23A and the second portion 23B. With this configuration, the contact area between the reinforcing plate 25 and the reservoir 23 is larger compared to when the upper end surface 251 of the reinforcing plate 25 is away from the step surface 236, making it easier to disperse the impact.

[0117] Therefore, the liquid ejection head 8 according to this embodiment has excellent impact resistance.

[0118] Furthermore, if there is a gap between the upper end surface 251 of the reinforcing plate 25 and the step surface 236, there is a risk that mist of ink will accumulate in the gap and soil the head main body 20. In contrast, in the liquid ejection head 8 according to this embodiment, the upper end surface 251 of the reinforcing plate 25 is in a state of abutting against the step surface 236 between the first portion 23A and the second portion 23B, and therefore soiling of the head main body 20 can be suppressed.

[0119] Furthermore, by configuring the upper end surface 251 of the reinforcing plate 25 to abut against the step surface 236 between the first portion 23A and the second portion 23B, it is possible to facilitate the alignment of the reinforcing plate 25 when manufacturing the liquid ejection head 8. This point will be described later.

[0120] Furthermore, the reinforcing plate 25 is positioned across the first portion 23A and the side surfaces 215, 235 of the flow path member 21. Therefore, in the liquid ejection head 8 according to this embodiment, separation between the flow path member 21 and the reservoir 23 is less likely to occur.

[0121] 8, the upper end surface 251 of the reinforcing plate 25 extends linearly in parallel with the stepped surface 236. The upper end surface 251 of the reinforcing plate 25 contacts the stepped surface 236 over the entire area from one end to the other in the longitudinal direction. This configuration can further improve impact resistance.

[0122] 10, a protruding distance D1 of the reinforcing plate 25 based on the side surface 235 of the first portion 23A is shorter than a protruding distance D2 of the second portion 23B based on the side surface 235 of the first portion 23A. In other words, the reinforcing plate 25 is contained within the step of the reservoir 23. With this configuration, the reinforcing plate 25 is less likely to come into contact with the outside, and peeling of the reinforcing plate 25 due to contact with the outside can be suppressed.

[0123] The protruding distance D3 of the reinforcing plate 25 with respect to the step surface 236 as the reference is shorter than the protruding distance of the flow path member 21 with respect to the step surface 236 as the reference, specifically, the sum D4 of the protruding distances of the first portion 23A and the flow path member 21. In other words, the lower end surface 252 of the reinforcing plate 25 is located higher than the second surface 21b of the flow path member 21. That is, the lower end surface 252 of the reinforcing plate 25 is located at a location farther away from the recording medium P. With this configuration, the reinforcing plate 25 is less likely to come into contact with the recording medium P. Therefore, peeling of the reinforcing plate 25 due to contact with the recording medium P can be suppressed.

[0124] The reinforcing plate 25 may be formed of the same material as the flow path member 21 and the reservoir 23. For example, the reinforcing plate 25, the flow path member 21, and the reservoir 23 may be formed of SUS (stainless steel). Specifically, the reinforcing plate 25, the flow path member 21, and the reservoir 23 may be formed of the same type of SUS. As an example, the reinforcing plate 25, the flow path member 21, and the reservoir 23 may be formed of martensitic SUS. The reinforcing plate 25, the flow path member 21, and the reservoir 23 may be formed of a metal other than SUS.

[0125] In this way, by using the same type of material for the reinforcing plate 25 as for the flow path member 21 and the reservoir 23, it is possible to match their linear expansion coefficients. This makes it less likely that the reinforcing plate 25 will peel off from the flow path member 21 and the reservoir 23 due to the difference in linear expansion coefficients when a temperature change occurs in the liquid ejection head 8.

[0126] <How to attach the reinforcing plate> Next, a method for attaching the reinforcing plate 25 will be described with reference to Figures 11 to 13. Figures 11 to 13 are explanatory diagrams of a method for attaching the reinforcing plate 25.

[0127] 11, first, the flow path member 21 and the reservoir 23 are placed so that the first portion 23A and the side surfaces 215, 235 of the flow path member 21 face upward. Then, adhesive 100 is applied to the first portion 23A and the side surfaces 215, 235 of the flow path member 21.

[0128] 12, the reinforcing plate 25 is placed on the first portion 23A to which the adhesive 100 has been applied and the side surfaces 215, 235 of the flow path member 21. At this time, the reinforcing plate 25 is placed on the first portion 23A and the side surfaces 215, 235 of the flow path member 21 while the upper end surface 251 of the reinforcing plate 25 is abutted against the step surface 236.

[0129] 13, a fixing jig J is used to fix the reinforcing plate 25 to the first portion 23A and the side surfaces 215, 235 of the flow path member 21. After this series of operations is performed for the remaining reinforcing plates 25, the adhesive 100 is cured by, for example, heat treatment. As a result, the reinforcing plate 25 is attached to the first portion 23A and the side surfaces 215, 235 of the flow path member 21 in a state where it abuts against the step surface 236.

[0130] In this way, the liquid ejection head 8 according to this embodiment is configured so that the upper end surface 251 of the reinforcing plate 25 abuts against the step surface 236, and therefore the reinforcing plate 25 can be easily positioned when attaching the reinforcing plate 25.

[0131] (First Modification) Fig. 14 is a schematic side view of the head main body 20 according to the first modified example, viewed along the longitudinal direction. As shown in Fig. 14, the adhesive 100 may be located not only between the main surface 250 of the reinforcing plate 25 and the side surface 235 of the first portion 23A, but also between the upper end surface 251 of the reinforcing plate 25 and the step surface 236. With this configuration, the bond between the reinforcing plate 25 and the reservoir 23 can be made stronger.

[0132] Furthermore, the adhesive 100 may also be located on the lower end surface 252 of the reinforcing plate 25. With this configuration, the contact area between the reinforcing plate 25 and the adhesive 100 increases, making it more difficult for the reinforcing plate 25 to peel off. Note that while Fig. 14 shows an example in which the entire lower end surface 252 of the reinforcing plate 25 is covered with the adhesive 100, it is sufficient that the adhesive 100 covers at least a portion of the lower end surface 252 of the reinforcing plate 25.

[0133] A protruding distance D5 of the adhesive 100 based on the step surface 236 is shorter than a protruding distance D4 of the flow path member 21 based on the step surface 236. In other words, the adhesive 100 is located above the second surface 21b of the flow path member 21. With this configuration, the adhesive 100 is less likely to come into contact with the recording medium P. Therefore, peeling of the reinforcing plate 25 due to contact of the adhesive 100 with the recording medium P can be suppressed.

[0134] (Second Modification) 15 is a schematic side view of the head main body 20 according to the second modification, viewed along the longitudinal direction. As shown in FIG. 15, the side surfaces of the plate-like members 231 and 232 and the narrow portion 233a that constitute the side surface 235 of the first portion 23A may be misaligned with each other in a direction perpendicular to the stacking direction. In this case, the side surface 235 of the first portion 23A has a recess 235a formed by the misalignment of the plate-like members 231 and 232 and the narrow portion 233a. A portion of the adhesive 100 may be located in this recess 235a.

[0135] In this way, a portion of the adhesive 100 enters the recess 235a of the side surface 235 of the first portion 23A, thereby increasing the contact area between the adhesive 100 and the first portion 23A, thereby strengthening the bond between the reinforcing plate 25 and the reservoir 23. Furthermore, the uneven side surface 235 of the first portion 23A is smoothed by the adhesive 100, which makes it easier to attach the reinforcing plate 25 to the side surface 235 of the first portion 23A.

[0136] The reservoir 23 may have adhesive 101 (an example of a second adhesive) between the plurality of plate-like members 231 to 233 for bonding them together. In this case, the adhesive 100 (an example of a first adhesive) may have a higher viscosity than the adhesive 101. With this configuration, it is easy to fill the recess 235a with the adhesive 100. Note that the adhesive 100 may have a higher viscosity than the adhesive 102 for bonding the first portion 23A and the flow path member 21 together.

[0137] Fig. 16 is a schematic enlarged view of region XVI shown in Fig. 15. As shown in Fig. 16, the side surface of plate-like member 232 constituting side surface 235 of first portion 23A may have recessed portion 232a recessed in a direction perpendicular to the stacking direction. Furthermore, plate-like member 232 may have multiple (for example, two) recessed portions 232a.

[0138] With this configuration, the contact area between the adhesive 100 and the first portion 23A is increased, so that the bond between the reinforcing plate 25 and the reservoir 23 can be made stronger.

[0139] Although the example shown here is one in which the recessed portion 232a is located on the side surface of the plate-like member 232, the other plate-like members 231 and 233 may also have recessed portions 232a on their side surfaces in the same manner.

[0140] As described above, the liquid ejection head according to the embodiment (for example, the liquid ejection head 8) includes a flow path member (for example, the flow path member 21), a reservoir (for example, the reservoir 23), and a reinforcing plate (for example, the reinforcing plate 25). The flow path member includes a nozzle (for example, the ejection hole 63) that ejects droplets and a pressure chamber (for example, the pressure chamber 62) that is connected to the nozzle. The reservoir supplies liquid to the pressure chamber. The reservoir includes, in order from the downstream side, a first region (for example, the first region 23A) in which a plurality of plate-like members (for example, the plate-like members 231 and 232 and the narrow portion 233a) are stacked, and a second region (for example, the second region 23B) whose width in a direction perpendicular to the stacking direction of the plate-like members is larger than that of the first region. The reinforcing plate has a main surface (for example, main surface 250) located on the side surface (for example, side surface 235) of the first portion, and an end surface (for example, upper end surface 251) located on the step surface (for example, step surface 236) between the first portion and the second portion.

[0141] Therefore, the liquid ejection head according to the embodiment has high impact resistance, and the reinforcing plate can be easily positioned.

[0142] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0143] 1. Printer 8 Liquid ejection head 20 Head body 21 Flow path member 22 Piezoelectric actuator substrate 23 Reservoir 23A 1st part 23B 2nd part 25 Reinforcement plate 62 Pressure Chamber 63 Discharge hole 100~102 Adhesive 215 Side of flow path member 231~233 Plate-shaped members 233a Narrow section 233b Wide part 235 Side of the first part 236 Step surface 250 Main surface of reinforcing plate 251 Upper end surface of reinforcing plate 252 Lower end surface of reinforcing plate J Fixture P Recording medium

Claims

1. a flow path member having a nozzle for ejecting droplets and a pressure chamber connected to the nozzle; a reservoir for supplying liquid to the pressure chamber; Reinforcement plate and and The reservoirs are, in order from the downstream side, a first portion in which a plurality of plate-like members are stacked; a second portion having a width in a direction perpendicular to the stacking direction of the plate-like members that is larger than that of the first portion; and A liquid ejection head, wherein the reinforcing plate has a main surface positioned on a side surface of the first portion and an end surface positioned on a step surface between the first portion and the second portion.

2. The liquid ejection head according to claim 1 , wherein the main surface of the reinforcing plate is positioned across a side surface of the first portion and a side surface of the flow path member.

3. The liquid ejection head according to claim 1 , wherein the end surface of the reinforcing plate extends parallel to the step surface.

4. The liquid ejection head according to claim 1 , wherein a protruding distance of the reinforcing plate from the side surface of the first portion is shorter than a protruding distance of the second portion from the side surface of the first portion.

5. The liquid ejection head according to claim 1 , wherein a protruding distance of the reinforcing plate from the step surface is shorter than a protruding distance of the flow path member from the step surface.

6. an adhesive positioned between the main surface of the reinforcing plate and a side surface of the first portion; The liquid ejection head according to claim 1 , wherein a portion of the adhesive is located in a recess formed by shifting the side surfaces of the plurality of plate-like members constituting the side surface of the first portion in a direction perpendicular to the stacking direction.

7. an adhesive positioned between the main surface of the reinforcing plate and a side surface of the first portion; The liquid ejection head according to claim 1 , wherein the adhesive is further positioned between the end face of the reinforcing plate and the step face.

8. an adhesive positioned between the main surface of the reinforcing plate and a side surface of the first portion; The liquid ejection head according to claim 1 , wherein the adhesive is further applied to an end surface of the reinforcing plate opposite to the end surface that is positioned on the stepped surface.

9. The liquid ejection head according to claim 8 , wherein a protruding distance of the adhesive from the step surface is shorter than a protruding distance of the flow path member from the step surface.

10. a first adhesive positioned between the main surface of the reinforcing plate and the side surface of the first portion; a second adhesive positioned between the plurality of plate-like members; and The liquid ejection head according to claim 1 , wherein the first adhesive has a higher viscosity than the second adhesive.

11. The liquid ejection head according to claim 1 , wherein the side surface of the plate-like member that constitutes the side surface of the first portion has a recessed portion recessed in a direction perpendicular to the stacking direction.

12. The liquid ejection head according to claim 1 , wherein the reinforcing plate, the flow path member, and the reservoir are made of the same type of metal member.

13. A liquid ejection head according to any one of claims 1 to 12 is provided. Recording device.

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