Liquid ejection head and recording apparatus

Abstract

This liquid discharge head comprises: a flow path member having a first surface and a second surface positioned on the opposite side from the first surface; and a pressurization part positioned on the first surface. The flow path member has: a second discharge hole and a first discharge hole positioned in the second surface; a first discrete flow path connected to the first discharge hole; a first pressurization chamber positioned on the upstream side of the first discharge hole in the first discrete flow path; a second discrete flow path connected to the second discharge hole; a second pressurization chamber positioned on the upstream side of the second discharge hole in the second discrete flow path; and a common manifold connected to the upstream side of the first discrete flow path and to the upstream side of the second discrete flow path. The first discrete flow path has a first communication flow path connecting between the first pressurization chamber and the first discharge hole. The second discrete flow path has a second communication flow path connecting between the second pressurization chamber and the second discharge hole. In a plan view, the second pressurization chamber is positioned closer to the manifold than the first pressurization chamber. At least a portion of the second communication flow path has a width different from the width of the first communication flow path.

Description

Technical Field

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

Background Art

[0002] As printing apparatuses, inkjet printers and inkjet plotters using an inkjet recording method are known. Such inkjet printing apparatuses are equipped with a liquid ejection head for ejecting a liquid.

[0003] Such a liquid ejection head includes a plurality of ejection holes, a plurality of pressure chambers respectively connected to the plurality of ejection holes, and a manifold commonly connected to the plurality of pressure chambers. The plurality of pressure chambers include a pressure chamber relatively far from the manifold and a pressure chamber relatively close to the manifold (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] A liquid ejection head according to an aspect of the embodiment includes a flow path member having a first surface and a second surface located on the opposite side of the first surface, and a pressurizing portion located on the first surface. The flow path member includes a first ejection hole and a second ejection hole located on the second surface, a first individual flow path connected to the first ejection hole, a first pressurizing chamber located upstream of the first ejection hole in the first individual flow path, a second individual flow path connected to the second ejection hole, a second pressurizing chamber located upstream of the second ejection hole in the second individual flow path, and a manifold commonly connected to the upstream side of the first individual flow path and the upstream side of the second individual flow path. The first individual flow path has a first communication flow path connecting the first pressurizing chamber and the first ejection hole. The second individual flow path has a second communication flow path connecting the second pressurizing chamber and the second ejection hole. The second pressurizing chamber is located closer to the manifold than the first pressurizing chamber in a plan view. At least a part of the width of the second communication flow path is different from the width of the first communication flow path.

Brief Description of the Drawings

[0006]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0007] Hereinafter, with reference to the accompanying drawings, embodiments of the liquid ejection head and the recording apparatus disclosed in the present application will be described. Note that the present disclosure is not limited by the embodiments shown below. Also, the drawings are schematic, and it should be noted that the dimensional relationships between elements, the ratios of the elements, etc. may be different from reality. Furthermore, there may be parts where the dimensional relationships and ratios are different between the drawings.

[0008] Also, in the embodiments shown below, expressions such as "constant", "orthogonal", "perpendicular", or "parallel" may be used, but these expressions do not necessarily require strict "constant", "orthogonal", "perpendicular", or "parallel". That is, each of the above expressions allows for deviations such as manufacturing accuracy and installation accuracy.

[0009] <Configuration of Printer> With reference to FIGS. 1 and 2, an overview of a printer 1, which is an example of a recording apparatus according to the embodiment, will be described. FIG. 1 is a side view schematically showing a schematic side of the printer 1 according to the embodiment. FIG. 2 is a plan view schematically showing a schematic plane of the printer 1 according to the embodiment.

[0010] As shown in FIG. 1, the printer 1 includes a paper feed roller 2, a guide roller 3, an applicator 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.

[0011] 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 conveyance rollers 6, the plurality of frames 7, the plurality of liquid ejection heads 8, the conveyance roller 9, the dryer 10, the conveyance roller 11, the sensor unit 12, and the recovery roller 13.

[0012] The printer 1 records images and characters on the printing paper P by landing droplets on the printing paper P. The printing paper P is wound in a state where it can be pulled out by the paper feed roller 2 before use. The printer 1 conveys the printing paper P from the paper feed roller 2 through the guide roller 3 and the coater 4 into the head case 5.

[0013] The coater 4 uniformly applies a coating agent to the printing paper P. As a result, the surface of the printing paper P can be treated, and thus the printing quality of the printer 1 can be improved.

[0014] The head case 5 houses the plurality of conveyance rollers 6, the plurality of frames 7, and the plurality of liquid ejection heads 8. Inside the head case 5, a space is formed that is isolated from the outside, except for a part such as the portion where the printing paper P enters and exits, which is connected to the outside.

[0015] The internal space of the head case 5 has at least one of the control factors such as temperature, humidity, and air pressure controlled by the control unit 14 as needed. The conveyance roller 6 conveys the printing paper P inside the head case 5 near the liquid ejection head 8.

[0016] The frame 7 is a rectangular flat plate and is positioned close above the printing paper P conveyed by the conveyance roller 6. Also, as shown in FIG. 2, a plurality (for example, four) of frames 7 are provided inside the head case 5 such that the longitudinal direction is orthogonal to the conveyance direction of the printing paper P. And each of the plurality of frames 7 is arranged at a predetermined interval along the conveyance direction of the printing paper P.

[0017] In the following description, the conveyance direction of the printing paper P may be referred to as the "sub-scanning direction", and the direction orthogonal to such sub-scanning direction and parallel to the printing paper P may be referred to as the "main scanning direction".

[0018] Liquid is supplied to the liquid ejection head 8 from a liquid tank (not shown), for example, ink. The liquid ejection head 8 ejects the liquid supplied from such liquid tank.

[0019] The control unit 14 controls the liquid ejection head 8 based on data such as images and characters, and causes the liquid to be ejected toward the printing paper P. The distance between the liquid ejection head 8 and the printing paper P is, for example, about 0.5 to 20 mm.

[0020] The liquid ejection head 8 is fixed to the frame 7. The liquid ejection head 8 is fixed to the frame 7, for example, at both longitudinal ends. The liquid ejection head 8 is fixed to the frame 7 such that the longitudinal direction is parallel to the main scanning direction.

[0021] 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 be a so-called serial printer.

[0022] A serial printer is a printer that alternately performs an operation of recording while moving the liquid ejection head 8 in a direction intersecting the conveyance direction of the printing paper P, for example, a direction substantially orthogonal, and the conveyance of the printing paper P.

[0023] As shown in FIG. 2, a plurality (for example, five) of liquid ejection heads 8 are provided on one frame 7. FIG. 2 shows an example in which two liquid ejection heads 8 are arranged in front and three liquid ejection heads 8 are arranged in the rear in the sub-scanning direction, and the liquid ejection heads 8 are arranged such that the centers of the respective liquid ejection heads 8 do not overlap in the sub-scanning direction.

[0024] A head group 8A is constituted by a plurality of liquid ejection heads 8 provided on one frame 7. The four head groups 8A are positioned along the sub-scanning direction. The liquid ejection heads 8 belonging to the same head group 8A are supplied with the same color ink. Thereby, the printer 1 can perform printing with four-color ink using the four head groups 8A.

[0025] The colors of the ink ejected from each head group 8A are, for example, magenta (M), yellow (Y), cyan (C), and black (K). The control unit 14 can print a color image on the printing paper P by controlling each head group 8A to eject a plurality of colors of ink onto the printing paper P.

[0026] Note that, in order to perform surface treatment on the printing paper P, a coating agent may be ejected from the liquid ejection head 8 onto the printing paper P.

[0027] Also, 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 appropriately changed according to the object to be printed and the printing conditions. For example, if the color to be printed on the printing paper P is single color and within the printable range of one liquid ejection head 8, the number of liquid ejection heads 8 mounted on the printer 1 may be one.

[0028] The printing paper P that has undergone printing processing inside the head case 5 is conveyed outside the head case 5 by the conveying roller 9 and passes through the inside of the dryer 10. The dryer 10 dries the printed printing paper P. The printing paper P dried by the dryer 10 is conveyed by the conveying roller 11 and collected by the collecting roller 13.

[0029] In the printer 1, by drying the printing paper P with the dryer 10, it is possible to suppress the adhesion between the printing papers P wound up overlapping each other and the rubbing of the undried liquid at the collecting roller 13.

[0030] The sensor unit 12 is composed of a position sensor, a speed sensor, a temperature sensor, etc. The control unit 14 can judge the states of the respective parts of the printer 1 based on the information from such a sensor unit 12 and control the respective parts of the printer 1.

[0031] In the printer 1 described so far, the case where printing paper P is used as the printing target (i.e., the recording medium) has been shown. However, the printing target in the printer 1 is not limited to the printing paper P, and a roll-shaped cloth or the like may be used as the printing target.

[0032] Further, instead of directly conveying the printing paper P, the above-described printer 1 may convey it by placing it on a conveying belt. By using the conveying belt, the printer 1 can use a single-sheet paper, a cut cloth, wood, a tile, etc. as the printing target.

[0033] Further, the above-described printer 1 may print a wiring pattern of an electronic device or the like by discharging a liquid containing conductive particles from the liquid discharge head 8.

[0034] Further, the above-described printer 1 may produce a chemical by discharging a predetermined amount of a liquid chemical agent or a liquid containing a chemical agent from the liquid discharge head 8 toward a reaction vessel or the like.

[0035] Further, the above-described printer 1 may be provided with a cleaning unit for cleaning the liquid discharge head 8. The cleaning unit performs cleaning of the liquid discharge head 8 by, for example, a wiping process or a capping process.

[0036] The wiping process is, for example, a process of removing the liquid adhering to the second surface 24b (see FIG. 3) of a flow path member 24 (see FIG. 3), which is the surface of the portion where the liquid is discharged, by wiping it with a flexible wiper.

[0037] The capping process is a process of covering the part where the liquid is discharged with a cap and repeating the discharge of the liquid to eliminate clogging of the first discharge hole 46 (see FIG. 5) and the second discharge hole 56 (see FIG. 5), and is carried out as follows. First, a cap is placed so as to cover the part where the liquid is discharged, for example, the second surface 24b of the flow path member 24 (this is called capping). As a result, a substantially sealed space is formed between the second surface 24b and the cap. Next, the discharge of the liquid is repeated in such a sealed space. Thereby, it is possible to remove the liquid having a higher viscosity than the standard state and foreign matters that were clogging the first discharge hole 46 and the second discharge hole 56.

[0038] <Configuration of liquid discharge head> FIG. 3 is an exploded perspective view showing a schematic configuration of the liquid discharge head 8 according to the embodiment.

[0039] As shown in FIG. 3, the liquid discharge head 8 includes a head body 20, a reservoir 21, an electric component substrate 22, and a head cover 23. Further, the head body 20 has a flow path member 24, a piezoelectric actuator substrate 25, a signal transmission part 26, and a drive IC 27.

[0040] The flow path member 24 of the head body 20 has a substantially flat plate shape, and has a first surface 24a which is one main surface and a second surface 24b located on the opposite side of the first surface 24a. The first surface 24a has an opening 40a (see FIG. 4), and the liquid is supplied from the reservoir 21 into the flow path member 24 through the opening 40a.

[0041] A plurality of first discharge holes 46 (see FIG. 4) and a plurality of second discharge holes 56 (see FIG. 4) for discharging the liquid onto the printing paper P are located on the second surface 24b. And inside the flow path member 24, a flow path for flowing the liquid from the first surface 24a to the second surface 24b is formed. Details of such a flow path member 24 will be described later.

[0042] The piezoelectric actuator substrate 25 is positioned on the first surface 24a of the flow path member 24. The piezoelectric actuator substrate 25 has a plurality of displacement elements 38 (see FIG. 5). The displacement element 38 is an example of a pressurizing unit. Details of such a piezoelectric actuator substrate 25 will be described later.

[0043] Two signal transmission parts 26 are electrically connected to the piezoelectric actuator substrate 25. Each signal transmission part 26 includes a plurality of drive ICs (Integrated Circuits) 27. In FIG. 3, for ease of understanding, illustration of one of the signal transmission parts 26 is omitted.

[0044] The signal transmission part 26 supplies signals to each displacement element 38 of the piezoelectric actuator substrate 25. The signal transmission part 26 is formed by, for example, an FPC (Flexible Printed Circuit) or the like.

[0045] The drive IC 27 is mounted on the signal transmission part 26. The drive IC 27 controls the drive of each displacement element 38 in the piezoelectric actuator substrate 25.

[0046] Note that the head body 20 has a liquid ejection surface for ejecting liquid and an opposite surface located on the opposite side of this liquid ejection surface. In the following, the liquid ejection surface will be described as the second surface 24b of the flow path member 24, and the opposite surface will be described as the first surface 24a of the flow path member 24.

[0047] The reservoir 21 is located on the opposite surface side of the head body 20 and is in contact with the first surface 24a other than the piezoelectric actuator substrate 25. Openings 21a are provided at both ends in the main scanning direction of the reservoir 21. The reservoir 21 has a flow path inside, and liquid is supplied from the outside through the openings 21a. The reservoir 21 has a function of supplying liquid to the flow path member 24 and a function of storing the supplied liquid.

[0048] On the surface of the reservoir 21 opposite to the head body 20, an electrical equipment substrate 22 is erected. At the end of the electrical equipment substrate 22 on the side of the reservoir 21, a plurality of connectors 28 are located. The end of the signal transmission part 26 is accommodated in each connector 28.

[0049] At the end of the electrical equipment substrate 22 opposite to the reservoir 21, a power supply connector 29 is located. The electrical equipment substrate 22 distributes the current supplied from the outside via the connector 29 to the connector 28 and supplies the current to the signal transmission part 26.

[0050] The head cover 23 is located on the opposite side of the head body 20 and covers the signal transmission part 26 and the electrical equipment substrate 22. Thereby, the liquid ejection head 8 can seal the signal transmission part 26 and the electrical equipment substrate 22.

[0051] Also, the head cover 23 has an opening 23a. The connector 29 of the electrical equipment substrate 22 is inserted so as to be exposed to the outside from the opening 23a.

[0052] The drive IC 27 is in contact with the inner side surface of the head cover 23. The drive IC 27 is, for example, pressed against the inner side surface of the head cover 23. Thereby, the heat generated by the drive IC 27 can be dissipated from the contact part on the side surface of the head cover 23.

[0053] Note that the liquid ejection head 8 may further include members other than the members shown in FIG. 3.

[0054] <Configuration of the head body> Next, the configuration of the head body 20 according to the embodiment will be described with reference to FIGS. 4 to 6. FIG. 4 is an enlarged plan view of the head body 20 according to the embodiment, FIG. 5 is a schematic cross-sectional view of the head body 20 according to the embodiment, and FIG. 6 is an enlarged view of the region surrounded by the dashed-dotted line shown in FIG. 4.

[0055] As shown in FIG. 4, the head body 20 has a flow path member 24 and a piezoelectric actuator substrate 25. The flow path member 24 has a supply manifold 40, a plurality of first pressurizing chambers 44, a plurality of second pressurizing chambers 54, a plurality of first discharge holes 46, and a plurality of second discharge holes 56. The supply manifold 40 is an example of a manifold.

[0056] The plurality of first pressurizing chambers 44 and the plurality of second pressurizing chambers 54 are connected to the supply manifold 40. The plurality of first discharge holes 46 are respectively connected to the plurality of first pressurizing chambers 44. The plurality of second discharge holes 56 are respectively connected to the plurality of second pressurizing chambers 54.

[0057] The first pressurizing chamber 44 and the second pressurizing chamber 54 open to the first surface 24a (see FIG. 5) of the flow path member 24. The first surface 24a of the flow path member 24 has an opening 40a that is connected to the supply manifold 40. Then, liquid is supplied from the reservoir 21 (see FIG. 2) into the interior of the flow path member 24 through such an opening 40a.

[0058] In the example of FIG. 4, four supply manifolds 40 are located inside the flow path member 24 of the head body 20. The supply manifold 40 has an elongated shape extending along the longitudinal direction of the flow path member 24, and openings 40a of the supply manifold 40 are formed in the first surface 24a of the flow path member 24 at both ends thereof.

[0059] In the flow path member 24, a plurality of first pressurizing chambers 44 and a plurality of second pressurizing chambers 54 are formed to extend two-dimensionally. The first pressurizing chamber 44 and the second pressurizing chamber 54 are hollow regions having a substantially rhombic planar shape with rounded corners. The first pressurizing chamber 44 and the second pressurizing chamber 54 open to the first surface 24a of the flow path member 24, and are closed by joining the piezoelectric actuator substrate 25 to such a first surface 24a.

[0060] The first pressurizing chamber 44 constitutes a first row of pressurizing chambers arranged in the longitudinal direction of the flow path member 24 (supply manifold 40), and the second pressurizing chamber 54 constitutes a second row of pressurizing chambers arranged in the longitudinal direction of the flow path member 24 (supply manifold 40). The first pressurizing chamber 44 belonging to the first row of pressurizing chambers and the second pressurizing chamber 54 belonging to the second row of pressurizing chambers adjacent to such first row of pressurizing chambers are arranged in a staggered manner.

[0061] And one pressurizing chamber group is constituted by two rows of first pressurizing chambers and two rows of second pressurizing chambers connected to one supply manifold 40. In the example of FIG. 4, the flow path member 24 has four such pressurizing chamber groups.

[0062] Also, the relative arrangements of the first pressurizing chamber 44 and the second pressurizing chamber 54 within each pressurizing chamber group are the same, and each pressurizing chamber group is arranged with a slight shift in the longitudinal direction.

[0063] The first discharge hole 46 and the second discharge hole 56 are arranged at positions avoiding the region of the flow path member 24 facing the supply manifold 40. That is, when the flow path member 24 is viewed through from the first surface 24a side, the first discharge hole 46 and the second discharge hole 56 do not overlap with the supply manifold 40.

[0064] Furthermore, in a plan view, the first discharge hole 46 and the second discharge hole 56 are arranged so as to fit within the mounting region of the piezoelectric actuator substrate 25. These first discharge hole 46 and second discharge hole 56 occupy a region having substantially the same size and shape as the piezoelectric actuator substrate 25 as one group.

[0065] And by displacing the displacement element 38 (see FIG. 5) of the corresponding piezoelectric actuator substrate 25, droplets are discharged from the first discharge hole 46 and the second discharge hole 56.

[0066] As shown in FIG. 5, the space between the supply manifold 40 and the first discharge hole 46 is connected by a first connection flow path 41, a first squeezing portion 42, a first supply flow path 43, a first pressurizing chamber 44, and a first communication flow path 45.

[0067] That is, the flow path member 24 has a first individual flow path C1 including a first connection flow path 41, a first squeezing portion 42, a first supply flow path 43, a first pressure chamber 44, and a first communication flow path 45. In the first individual flow path C1, in the liquid flow direction, the first connection flow path 41 is located near the supply manifold 40, and the first communication flow path 45 is located near between the first discharge holes 46.

[0068] When the direction from the first surface 24a to the second surface 24b is defined as the first direction D1, the first connection flow path 41 extends in the first direction D1, the first squeezing portion 42 extends in a direction perpendicular to the first direction D1, and the first supply flow path 43 extends in the first direction D1. Also, the first pressure chamber 44 extends in a direction perpendicular to the first direction D1, and the first communication flow path 45 extends in the first direction D1.

[0069] Similarly, between the supply manifold 40 and the second discharge hole 56, there are connections through a second connection flow path 51, a second squeezing portion 52, a second supply flow path 53, a second pressure chamber 54, and a second communication flow path 55.

[0070] That is, the flow path member 24 has a second individual flow path C2 including a second connection flow path 51, a second squeezing portion 52, a second supply flow path 53, a second pressure chamber 54, and a second communication flow path 55. In the second individual flow path C2, in the liquid flow direction, the second connection flow path 51 is located near the supply manifold 40, and the second communication flow path 55 is located near the second discharge hole 56.

[0071] The second connection flow path 51 extends in the first direction D1, the second squeezing portion 52 extends in a direction perpendicular to the first direction D1, and the second supply flow path 53 extends in the first direction D1. Also, the second pressure chamber 54 extends in a direction perpendicular to the first direction D1, and the second communication flow path 55 extends in the first direction D1.

[0072] The first individual flow path C1 has a first squeezing portion 42 that is narrower in width than other portions and is upstream of the first pressure chamber 44. Since such a first squeezing portion 42 is narrower in width than other portions in the first individual flow path C1, the flow path resistance is high.

[0073] Accordingly, in the embodiment, it is possible to suppress the pressure generated in the first pressure chamber 44 from escaping to the supply manifold 40 instead of the first discharge hole 46. Therefore, according to the embodiment, it is possible to efficiently discharge the liquid from the first discharge hole 46.

[0074] The second individual flow path C2 has a second constriction 52 that is narrower in width than other portions on the upstream side of the second pressure chamber 54. Since such a second constriction 52 is narrower in width than other portions in the second individual flow path C2, the flow path resistance is high.

[0075] Accordingly, in the embodiment, it is possible to suppress the pressure generated in the second pressure chamber 54 from escaping to the supply manifold 40 instead of the second discharge hole 56. Therefore, according to the embodiment, it is possible to efficiently discharge the liquid from the second discharge hole 56.

[0076] As shown in FIG. 5, the flow path member 24 has a laminated structure in which a plurality of plates are laminated. These plates are, in order from the first surface 24a of the flow path member 24, a cavity plate 24A, a base plate 24B, an aperture (constriction) plate 24C, 24D, a supply plate 24E, a manifold plate 24F, 24G, 24H, a cover plate 24I, and a nozzle plate 24J.

[0077] Note that FIG. 5 shows an example of the laminated structure of each plate according to the embodiment, and the example shown in FIG. 5 does not need to be particularly limited. For example, the manifold plates 24F, 24G, 24H may be configured by laminating three or more plates. Further, the cover plate 24I may be configured by laminating a plurality of plates.

[0078] A large number of holes are formed in the plurality of plates constituting the flow path member 24, and by connecting such a large number of holes, the supply manifold 40, the first individual flow path C1, and the second individual flow path C2 are configured inside the flow path member 24.

[0079] In the embodiment, by setting the thickness of these plates to about 10 to 300 μm, the accuracy of the formed holes can be increased.

[0080] The first individual flow path C1 has a first connecting flow path 45 that connects the first pressure chamber 44 and the first discharge hole 46 on the downstream side of the first pressure chamber 44. Further, the second individual flow path C2 has a second connecting flow path 55 that connects the second pressure chamber 54 and the second discharge hole 56 on the downstream side of the second pressure chamber 54.

[0081] Here, in the embodiment, as shown in FIG. 6, the second pressure chamber 54 is located closer to the supply manifold 40 than the first pressure chamber 44 in a plan view. That is, in the embodiment, in a plan view, the first pressure chamber 44 is relatively far from the supply manifold 40, and the second pressure chamber 54 is relatively close to the supply manifold 40. In the example of FIG. 6, in a plan view, the first pressure chamber 44 is located away from the supply manifold 40 and does not overlap with the supply manifold 40, but the second pressure chamber 54 has a portion that overlaps with the supply manifold 40.

[0082] And, in the embodiment, as shown in FIGS. 5 and 6, the width of the second connecting flow path 55 is different from the width of the first connecting flow path 45. For example, the width of the second connecting flow path 55 is larger than the width of the first connecting flow path 45.

[0083] By the way, in the liquid discharge head 8, the second pressure chamber 54 that is relatively close to the supply manifold 40 has lower rigidity than the first pressure chamber 44 that is relatively far from the supply manifold 40, and is more likely to be displaced by the pressure from the displacement element 38. Thus, due to the variation in the displacement amount between the first pressure chamber 44 and the second pressure chamber 54, the discharge speed of the liquid may vary between the first discharge hole 46 and the second discharge hole 56.

[0084] FIG. 7 is a diagram for explaining the variation in the displacement amount between the first pressure chamber 44 and the second pressure chamber 54. FIG. 7 shows the displacement amount of the first pressure chamber 44 belonging to the first pressure chamber row and the displacement amount of the second pressure chamber 54 belonging to the second pressure chamber row.

[0085] The row numbers shown in FIG. 7 are numbers indicating the positions in the short direction of the flow path member 24 of the first pressurizing chamber row and the second pressurizing chamber row. For example, for the 8 rows of the first pressurizing chamber row and the 8 rows of the second pressurizing chamber row shown in FIG. 4, numbers 1 to 16 are assigned as row numbers in order from the left side. Row numbers 1, 4, 5, 8, 9, 12, 13, 16 correspond to the first pressurizing chamber row, and row numbers 2, 3, 6, 7, 10, 11, 14, 15 correspond to the second pressurizing chamber row. The column numbers shown in FIG. 7 are numbers indicating the positions in the longitudinal direction of the flow path member 24 of the first pressurizing chamber 44 belonging to the first pressurizing chamber row and the second pressurizing chamber 54 belonging to the second pressurizing chamber row.

[0086] As shown in FIG. 7, the displacement amount of the second pressurizing chamber 54 relatively close to the supply manifold 40 is larger than that of the first pressurizing chamber 44 relatively far from the supply manifold 40. Thus, when there is a variation in the displacement amount between the first pressurizing chamber 44 and the second pressurizing chamber 54, the discharge speed of the liquid at the second discharge hole 56 connected to the second pressurizing chamber 54 increases compared to the first discharge hole 46 connected to the first pressurizing chamber 44. As a result, the uniformity of the discharge speed of the liquid between the first discharge hole 46 and the second discharge hole 56 is impaired.

[0087] Therefore, in the embodiment, as shown in FIGS. 5 and 6, by making the width of the second communication flow path 55 larger than the width of the first communication flow path 45, the discharge speed of the liquid between the first discharge hole 46 and the second discharge hole 56 is made uniform.

[0088] FIG. 8 is a diagram for explaining an example of the relationship between the width of the second communication flow path 55 and the discharge speed of the liquid discharged from the second discharge hole 56. The inventors of the present invention supplied liquid into the flow path member 24 while changing the width (flow path width) of the second communication flow path 55, and examined the discharge speed of the liquid discharged from the second discharge hole 56 by simulation. The results of such simulation are shown in FIG. 8.

[0089] As shown in FIG. 8, the discharge velocity of the liquid discharged from the second discharge hole 56 reaches its maximum value when the width of the second communication channel 55 is approximately 200 μm, and decreases from the maximum value when the width of the second communication channel 55 is smaller or larger than approximately 200 μm. When the width of the second communication channel 55 is small, the flow resistance of the second communication channel 55 increases, and the pressure wave generated in the second pressure chamber 54 is not efficiently propagated to the second discharge hole 56, so it is considered that the discharge velocity of the liquid decreases. Also, when the width of the second communication channel 55 is large, the pressure wave generated in the second pressure chamber 54 is absorbed by the liquid and attenuates, so it is considered that the discharge velocity of the liquid decreases. Although the explanation is omitted here, regarding the discharge velocity of the liquid discharged from the first discharge hole 46 as well, simulation results similar to those in FIG. 8 can be obtained according to the change in the width of the first communication channel 45.

[0090] In the liquid discharge head 8, the widths of the first communication channel 45 and the second communication channel 55 are generally set so that the discharge velocity of the liquid discharged from the discharge holes (the first discharge hole 46 and the second discharge hole 56) reaches its maximum value. For example, in the example of FIG. 8, the widths of the first communication channel 45 and the second communication channel 55 are set in the vicinity of 200 μm, which is a common set value at which the discharge velocity of the liquid reaches its maximum value. By setting the widths of the first communication channel 45 and the second communication channel 55 to a common set value, theoretically, there should be no variation in the discharge velocity of the liquid between the first discharge hole 46 and the second discharge hole 56. However, in reality, as described above, due to the variation in the displacement amount between the first pressure chamber 44 and the second pressure chamber 54, the discharge velocity of the liquid at the second discharge hole 56 increases compared to the first discharge hole 46. As a result, the uniformity of the discharge velocity of the liquid between the first discharge hole 46 and the second discharge hole 56 is impaired.

[0091] In contrast, in the embodiment, by making the width of the second communication channel 55 larger than the width of the first communication channel 45, the discharge velocity of the liquid discharged from the second discharge hole 56 is decreased so as to approach the discharge velocity of the liquid discharged from the first discharge hole 46. Therefore, according to the embodiment, the uniformity of the discharge velocity of the liquid between the first discharge hole 46 and the second discharge hole 56 can be improved.

[0092] In the embodiment, the case where the width of the second communication channel 55 is larger than the width of the first communication channel 45 is taken as an example. However, the width of the second communication channel 55 may be smaller than the width of the first communication channel 45. In short, it is only necessary that the width of the second communication channel 55 is different from the width of the first communication channel 45. Also, it is not always necessary that the entire width of the second communication channel 55 is different from the width of the first communication channel 45. For example, the width of a part of the second communication channel 55 may be different from the width of the first communication channel 45, and the width of another part of the second communication channel 55 may be the same as the width of the first communication channel 45. In short, it is only necessary that the width of at least a part of the second communication channel 55 is different from the width of the first communication channel 45.

[0093] Also, in the embodiment, the width of the second communication channel 55 is preferably 0.5 to 2.5% larger than the width of the first communication channel 45. For example, when the width of the first communication channel 45 is about 200 μm, the width of the second communication channel 55 is preferably about 1 to 5 μm larger than the width of the first communication channel 45. Thereby, it is possible to suppress an excessive decrease in the discharge speed of the liquid discharged from the second discharge hole 56. Therefore, according to the embodiment, the uniformity of the discharge speed of the liquid between the first discharge hole 46 and the second discharge hole 56 can be further improved.

[0094] Also, in the embodiment, as shown in FIG. 5, in each of the manifold plates 24F, 24G, and 24H, the diameter r2 of the hole for forming the second communication channel 55 is preferably larger than the diameter r1 of the hole for forming the first communication channel 45.

[0095] FIG. 9 is a diagram showing a specific example of the diameter of the holes in the manifold plate 24H. In FIG. 9, the diameter r1 of the holes for forming the first communication channel 45 and the diameter r2 of the holes for forming the second communication channel 55 are shown. The line numbers shown in FIG. 9 are numbers indicating the positions in the short side direction of the flow path member 24 of the holes for forming the first communication channel 45 and the holes for forming the second communication channel 55. Numbers similar to the line numbers of the corresponding first pressure chamber rows and second pressure chamber rows are assigned as line numbers to these holes. The line numbers 1, 4, 5, 8, 9, 12, 13, 16 correspond to the holes for forming the first communication channel 45, and the line numbers 2, 3, 6, 7, 10, 11, 14, 15 correspond to the holes for forming the second communication channel 55. As shown in FIG. 9, in the manifold plate 24H, the diameter r2 of the holes for forming the second communication channel 55 is larger than the diameter r1 of the holes for forming the first communication channel 45. Although the explanation is omitted here, in each of the manifold plates 24F and 24G, the diameter r2 of the holes for forming the second communication channel 55 is larger than the diameter r1 of the holes for forming the first communication channel 45. That is, in each of the manifold plates 24F, 24G, and 24H, the diameter r2 of the holes for forming the second communication channel 55 is larger than the diameter r1 of the holes for forming the first communication channel 45. Thereby, by aligning and laminating the manifold plates 24F, 24G, and 24H so that the respective holes communicate with each other, the first communication channel 45 and the second communication channel 55 can be easily formed in the flow path member 24.

[0096] In addition, in the embodiment, as shown in FIG. 5, the thickness of each of the manifold plates 24F, 24G, and 24H may be greater than that of the other plates included in the plurality of plates constituting the flow path member 24. For example, in the embodiment, the thickness of each of the manifold plates 24F, 24G, and 24H is greater than that of the other plates such as the cavity plate 24A. Since the thickness of each of the manifold plates 24F, 24G, and 24H is greater than that of the other plates, the volume of the second communication flow path 55 in the manifold plates 24F, 24G, and 24H can be made larger than the volume of the second communication flow path 55 in the other plates. As a result, the pressure wave generated in the second pressure chamber 54 is absorbed by the liquid in the second communication flow path 55 in the manifold plates 24F, 24G, and 24H and attenuates efficiently, so that the adjustment range of the discharge speed of the liquid discharged from the second discharge hole can be widened. Therefore, according to the embodiment, the uniformity of the discharge speed of the liquid between the first discharge hole 46 and the second discharge hole 56 can be further improved.

[0097] In addition, in the embodiment, as shown in FIG. 5, in each of the manifold plates 24F, 24G, 24H and the other plates, the diameter r2 of the hole for forming the second communication flow path 55 may be larger than the diameter r1 of the hole for forming the first communication flow path 45. For example, in each of the base plate 24B, the aperture (squeezing) plates 24C, 24D, the supply plate 24E, and the cover plate 24I, the diameter r2 of the hole for forming the second communication flow path 55 is larger than the diameter r1 of the hole for forming the first communication flow path 45. Thereby, not only the volume of the second communication flow path 55 in the manifold plates 24F, 24G, 24H but also the volume of the second communication flow path 55 in the other plates can be increased. For this reason, the pressure wave generated in the second pressure chamber 54 is absorbed by the liquid in the second communication flow path 55 in the manifold plates 24F, 24G, 24H and the other plates and attenuates efficiently, so that the adjustment range of the discharge speed of the liquid discharged from the second discharge hole 56 can be widened. Therefore, according to the embodiment, the uniformity of the discharge speed of the liquid between the first discharge hole 46 and the second discharge hole 56 can be further improved.

[0098] Continue the description of other parts of the head body 20. As shown in FIG. 5, the piezoelectric actuator substrate 25 has piezoelectric ceramic layers 25A and 25B, a common electrode 33, individual electrodes 34, connection electrodes 35, dummy electrodes 36, and surface electrodes 37 (see FIG. 4).

[0099] Also, in the piezoelectric actuator substrate 25, the piezoelectric ceramic layer 25B, the common electrode 33, the piezoelectric ceramic layer 25A, and the individual electrode 34 are laminated in this order.

[0100] The piezoelectric ceramic layers 25A and 25B both extend so as to straddle a plurality of first pressure chambers 44 and second pressure chambers 54. The piezoelectric ceramic layers 25A and 25B each have a thickness of about 20 μm. The piezoelectric ceramic layers 25A and 25B are made of, for example, a lead zirconate titanate (PZT)-based ceramic material having ferroelectricity.

[0101] The common electrode 33 is formed over substantially the entire surface in the plane direction in the region between the piezoelectric ceramic layer 25A and the piezoelectric ceramic layer 25B. That is, the common electrode 33 overlaps all of the first pressure chambers 44 and the second pressure chambers 54 in the region facing the piezoelectric actuator substrate 25.

[0102] The thickness of the common electrode 33 is about 2 μm. The common electrode 33 is made of, for example, a metal material such as an Ag-Pd system.

[0103] The individual electrode 34 has a main body electrode 34a and a lead-out electrode 34b. The main body electrode 34a is located in the region on the piezoelectric ceramic layer 25A that faces the first pressure chamber 44 and the second pressure chamber 54. The main body electrode 34a is slightly smaller than the first pressure chamber 44 and the second pressure chamber 54 and has a shape substantially similar to the first pressure chamber 44 and the second pressure chamber 54.

[0104] The lead-out electrode 34b is drawn out from the main body electrode 34a to an area outside the regions facing the first pressure chamber 44 and the second pressure chamber 54. The individual electrode 34 is made of a metal material such as an Au-based material, for example.

[0105] The connection electrode 35 is located on the lead-out electrode 34b, has a thickness of about 15 μm, and is formed in a convex shape. Also, the connection electrode 35 is electrically connected to an electrode provided in the signal transmission part 26 (see FIG. 3). The connection electrode 35 is made of, for example, silver-palladium containing glass frit.

[0106] The dummy electrode 36 is located on the piezoelectric ceramic layer 25A and is positioned so as not to overlap various electrodes such as the individual electrode 34. The dummy electrode 36 connects the piezoelectric actuator substrate 25 and the signal transmission part 26 and enhances the connection strength.

[0107] Also, the dummy electrode 36 equalizes the distribution of the contact positions between the piezoelectric actuator substrate 25 and the signal transmission part 26 and stabilizes the electrical connection. The dummy electrode 36 is preferably made of the same material as the connection electrode 35 and is preferably formed in the same process as the connection electrode 35.

[0108] The surface electrode 37 shown in FIG. 4 is formed on the piezoelectric ceramic layer 25A at a position avoiding the individual electrode 34. The surface electrode 37 is connected to the common electrode 33 through a via hole formed in the piezoelectric ceramic layer 25A.

[0109] Thereby, the surface electrode 37 is grounded and held at the ground potential. The surface electrode 37 is preferably made of the same material as the individual electrode 34 and is preferably formed in the same process as the individual electrode 34.

[0110] The plurality of individual electrodes 34 are each electrically connected to the control unit 14 (see FIG. 1) individually via the signal transmission unit 26 and wiring in order to control the potential individually. Then, when the individual electrode 34 and the common electrode 33 are set to different potentials to apply an electric field in the polarization direction of the piezoelectric ceramic layer 25A, the portion in the piezoelectric ceramic layer 25A where the electric field is applied operates as an active portion that is distorted by the piezoelectric effect.

[0111] That is, in the piezoelectric actuator substrate 25, the portions of the individual electrode 34, the piezoelectric ceramic layers 25A and 25B, and the common electrode 33 that face the first pressurizing chamber 44 and the second pressurizing chamber 54 function as the displacement element 38.

[0112] Then, when the displacement element 38 undergoes unimorph deformation, the first pressurizing chamber 44 and the second pressurizing chamber 54 are pressed, and liquid is discharged from the first discharge hole 46 and the second discharge hole 56.

[0113] Next, the driving procedure of the liquid discharge head 8 according to the embodiment will be described. The individual electrode 34 is set in advance to a potential higher than that of the common electrode 33 (hereinafter also referred to as a high potential). Then, each time there is a discharge request, the control unit 14 temporarily sets the individual electrode 34 to the same potential as the common electrode 33 (hereinafter also referred to as a low potential), and then sets it to the high potential again at a predetermined timing.

[0114] Thereby, at the timing when the individual electrode 34 becomes the low potential, the piezoelectric ceramic layers 25A and 25B return to their original shapes, and the volumes of the first pressurizing chamber 44 and the second pressurizing chamber 54 increase from the initial state, that is, the state of the high potential.

[0115] At this time, since a negative pressure is applied to the first pressurizing chamber 44 and the second pressurizing chamber 54, the liquid in the supply manifold 40 is sucked into the first pressurizing chamber 44 and the second pressurizing chamber 54.

[0116] After that, at the timing when the individual electrode 34 is set to the high potential again, the piezoelectric ceramic layers 25A and 25B are deformed so as to protrude toward the first pressurizing chamber 44 and the second pressurizing chamber 54.

[0117] That is, as the volumes of the first pressure chamber 44 and the second pressure chamber 54 decrease, the pressures in the first pressure chamber 44 and the second pressure chamber 54 become positive pressures. As a result, the pressure of the liquid inside the first pressure chamber 44 and the second pressure chamber 54 rises, and droplets are discharged from the first discharge hole 46 and the second discharge hole 56.

[0118] That is, in order to discharge droplets from the first discharge hole 46 and the second discharge hole 56, the control unit 14 supplies a drive signal including a pulse referenced to a high potential to the individual electrodes 34. This pulse width may be set as AL (Acoustic Length), which is the time length for the pressure wave to propagate from the first connection flow path 41 to the first discharge hole 46 (or from the second connection flow path 51 to the second discharge hole 56).

[0119] As a result, when the interiors of the first pressure chamber 44 and the second pressure chamber 54 invert from a negative pressure state to a positive pressure state, the pressures of both are combined, and droplets can be discharged with a stronger pressure.

[0120] In addition, in halftone printing, halftone representation is performed by adjusting the amount (volume) of droplets, that is, the number of droplets continuously discharged from the first discharge hole 46 and the second discharge hole 56, namely, the droplet discharge frequency. For this reason, droplet discharges of the number corresponding to the specified halftone representation are continuously performed from the first discharge hole 46 and the second discharge hole 56 corresponding to the specified dot area.

[0121] Generally, when continuously performing liquid discharge, the interval between pulses supplied to discharge droplets may be set as AL. As a result, the cycle of the residual pressure wave of the pressure generated when discharging the previously discharged droplets matches the cycle of the pressure wave of the pressure generated when discharging the subsequently discharged droplets.

[0122] Therefore, the residual pressure wave and the pressure wave can be superimposed to amplify the pressure for discharging droplets. In this case, the speed of the subsequently discharged droplets becomes faster, and the landing points of a plurality of droplets become closer.

[0123] <Embodiments of Each Type of Head Body> Regarding the embodiments of each type of the head body 20 according to the embodiment, reference will be made to FIGS. 10 to 12 for description. FIG. 10 is a schematic cross-sectional view of the head body 20 according to another embodiment 1.

[0124] In the following embodiments of each type, the same parts as those in the embodiment are denoted by the same reference numerals, and redundant descriptions are omitted.

[0125] As shown in FIG. 10, in another embodiment 1, at least one of the manifold plates 24F, 24G, 24H and the other manifold plates have different diameters of the holes for forming the second communication flow path 55. For example, the diameter r21 of the holes for forming the second communication flow path 55 of the manifold plates 24F, 24G is larger than the diameter r22 of the holes for forming the second communication flow path 55 of the manifold plate 24H. Thereby, since the volume of the second communication flow path 55 in the manifold plates 24F, 24G, 24H can be finely adjusted, the adjustment range of the discharge speed of the liquid discharged from the second discharge hole 56 can be widened. Therefore, according to another embodiment 1, the uniformity of the discharge speed of the liquid between the first discharge hole 46 and the second discharge hole 56 can be further improved.

[0126] Also, in another embodiment 1, the central axes of the holes (holes for forming the second communication flow path 55) of the manifold plates 24F, 24G, 24H coincide. Thereby, even when the diameters of the holes (holes for forming the second communication flow path 55) of the manifold plates 24F, 24G, 24H are different, the liquid can flow along the central axes of such holes in the second communication flow path 55. Therefore, according to another embodiment 1, the turbulence of the liquid flow in the second communication flow path 55 can be suppressed.

[0127] FIG. 11 is a schematic cross-sectional view of the head body 20 according to another embodiment 2.

[0128] As shown in FIG. 11, in another Embodiment 2, the diameters of the holes for forming the second communication flow path 55 in the manifold plates 24F, 24G, and 24H are different from each other. Thereby, since the volume of the second communication flow path 55 in the manifold plates 24F, 24G, and 24H can be finely adjusted, the adjustment range of the discharge speed of the liquid discharged from the second discharge hole 56 can be widened. Therefore, according to another Embodiment 2, the uniformity of the discharge speed of the liquid between the first discharge hole 46 and the second discharge hole 56 can be further improved.

[0129] Also, in another Embodiment 2, the diameters of the holes (holes for forming the second communication flow path 55) of the manifold plates 24F, 24G, and 24H become smaller as the position of the holes (holes for forming the second communication flow path 55) in the first direction D1 approaches the second surface 24b. That is, the diameter r22 of the hole of the manifold plate 24G is smaller than the diameter r21 of the hole of the manifold plate 24F, and the diameter r23 of the hole of the manifold plate 24H is smaller than the diameter r22 of the hole of the manifold plate 24G. Thereby, since the volume of the second communication flow path 55 in the manifold plates 24F, 24G, and 24H can be gradually reduced toward the downstream side of the liquid, the flow velocity of the liquid in the second communication flow path 55 can be increased as it approaches the second discharge hole 56. Therefore, according to another Embodiment 2, the discharge of air and foreign matter from the second discharge hole 56 can be promoted.

[0130] Also, in another Embodiment 2, similar to another Embodiment 1, the central axes of the holes (holes for forming the second communication flow path 55) of the manifold plates 24F, 24G, and 24H coincide. Therefore, according to another Embodiment 2, similar to another Embodiment 1, the disturbance of the flow of the liquid in the second communication flow path 55 can be suppressed.

[0131] FIG. 12 is an enlarged plan view of the head body 20 according to another Embodiment 3.

[0132] As shown in FIG. 12, in the flow path member 24 of the head body 20 according to another Embodiment 3, the position of the first pressurization chamber 44 is different from that in the embodiment. Specifically, in a plan view, the first pressurization chamber 44 is positioned so as to be closer to the supply manifold 40 as a whole compared to the embodiment, and has a portion overlapping with the supply manifold 40.

[0133] And in another Embodiment 3, in a plan view, the area of the portion of the first pressurization chamber 44 overlapping with the supply manifold 40 is smaller than the area of the portion of the second pressurization chamber 54 overlapping with the supply manifold 40. Thereby, the first pressurization chamber 44 and the second pressurization chamber 54 can be arranged in the flow path member 24 with good space efficiency. Therefore, according to another Embodiment 3, since the flow path member 24 can be miniaturized, the head body 20 can be miniaturized.

[0134] As described above, the embodiments of the present disclosure have been described. However, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the spirit thereof. For example, in the above-described embodiment, an example in which the flow path member 24 is composed of a plurality of laminated plates has been shown. However, the flow path member 24 is not limited to the case where it is composed of a plurality of laminated plates.

[0135] For example, the flow path member 24 may be configured by forming the supply manifold 40, the first individual flow path C1, the second individual flow path C2, etc. by an etching process.

[0136] As described above, the liquid ejection head (e.g., liquid ejection head 8) according to the embodiment includes a flow path member (e.g., flow path member 24) having a first surface (e.g., first surface 24a) and a second surface (e.g., second surface 24b) located on the opposite side of the first surface, and a pressurizing portion (e.g., displacement element 38) located on the first surface. The flow path member includes a first ejection hole (e.g., first ejection hole 46) and a second ejection hole (e.g., second ejection hole 56) located on the second surface, a first individual flow path (e.g., first individual flow path C1) connected to the first ejection hole, a first pressurizing chamber (e.g., first pressurizing chamber 44) located upstream of the first ejection hole in the first individual flow path, a second individual flow path (e.g., second individual flow path C2) connected to the second ejection hole, a second pressurizing chamber (e.g., second pressurizing chamber 54) located upstream of the second ejection hole in the second individual flow path, and a manifold (e.g., supply manifold 40) commonly connected to the upstream sides of the first individual flow path and the second individual flow path. The first individual flow path has a first communication flow path (e.g., first communication flow path 45) connecting the first pressurizing chamber and the first ejection hole. The second individual flow path has a second communication flow path (e.g., second communication flow path 55) connecting the second pressurizing chamber and the second ejection hole. The second pressurizing chamber is located closer to the manifold than the first pressurizing chamber in a plan view. At least a part of the width of the second communication flow path is different from the width of the first communication flow path. Thus, according to the liquid ejection head according to the embodiment, the uniformity of the liquid ejection speed can be improved.

[0137] Also, at least a part of the width of the second communication flow path may be larger than the width of the first communication flow path. Thus, according to the liquid ejection head according to the embodiment, since the ejection speed of the liquid ejected from the second ejection hole can be reduced so as to approach the ejection speed of the liquid ejected from the first ejection hole, the uniformity of the liquid ejection speed can be improved.

[0138] Further, the width of at least a part of the second communication channel may be 0.5 to 2.5% larger than the width of the first communication channel. Thus, according to the liquid ejection head according to the embodiment, since it is possible to suppress an excessive decrease in the ejection speed of the liquid ejected from the second ejection hole, the uniformity of the ejection speed of the liquid can be further improved.

[0139] Further, the flow path member may have a laminated structure in which a plurality of plates are laminated. The plurality of plates may include a plurality of manifold plates (for example, manifold plates 24F, 24G, 24H) each having a plurality of holes for forming a manifold, a first communication channel, and a second communication channel. In each of the plurality of manifold plates, the diameter (for example, diameter r2) of the hole for forming the second communication channel may be larger than the diameter (for example, diameter r1) of the hole for forming the first communication channel. Thus, according to the liquid ejection head according to the embodiment, by aligning and laminating the plurality of manifold plates so that the respective holes communicate with each other, the first communication channel and the second communication channel can be easily formed in the flow path member.

[0140] Further, the thickness of each of the plurality of manifold plates may be thicker than other plates included in the plurality of plates. Thus, according to the liquid ejection head according to the embodiment, since the pressure wave generated in the second pressure chamber is absorbed by the liquid in the second communication channel in the plurality of manifold plates and efficiently attenuated, the adjustment range of the ejection speed of the liquid ejected from the second ejection hole can be widened.

[0141] Further, the diameter of the hole for forming the second communication channel in at least one of the plurality of manifold plates may be different from that of the other manifold plates. Thus, according to the liquid ejection head according to the embodiment, since the volume of the second communication channel in the plurality of manifold plates can be finely adjusted, the adjustment range of the ejection speed of the liquid ejected from the second ejection hole can be widened.

[0142] Further, the diameters of the holes for forming the second communication channels in the plurality of manifold plates may be different from each other. According to the liquid ejection head according to the embodiment, since the volume of the second communication channels in the plurality of manifold plates can be finely adjusted, the adjustment range of the ejection speed of the liquid ejected from the second ejection holes can be widened.

[0143] Also, when the direction from the first surface to the second surface is defined as the first direction (for example, the first direction D1), the diameters of the holes in the plurality of manifold plates may become smaller as the position of the holes in the first direction approaches the second surface. According to the liquid ejection head according to the embodiment, the discharge of air and foreign matter from the second ejection holes can be promoted.

[0144] Also, the central axes of the holes in the plurality of manifold plates may coincide. According to the liquid ejection head according to the embodiment, the turbulence of the liquid flow in the second communication channels can be suppressed.

[0145] Also, the plurality of plates may be other plates different from the plurality of manifold plates, and may include other plates (for example, the base plate 24B, the aperture (squeezing) plates 24C and 24D, the supply plate 24E, and the cover plate 24I) having a plurality of holes for forming the first communication channel and the second communication channel. In each of the plurality of manifold plates and the other plates, the diameter of the hole for forming the second communication channel may be larger than the diameter of the hole for forming the first communication channel. According to the liquid ejection head according to the embodiment, since the pressure wave generated in the second pressure chamber is absorbed and attenuated by the liquid in the second communication channels in the plurality of manifold plates and the other plates, the adjustment range of the ejection speed of the liquid ejected from the second ejection holes can be widened.

[0146] Further effects and other embodiments can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the specific details and representative embodiments presented and described as above. Accordingly, various modifications are possible without departing from the spirit or scope of the general inventive concept defined by the appended claims and their equivalents.

Explanation of Signs

[0147] 1 Printer 8 Liquid ejection head 14 Control unit 20 Head body 24 Flow path member 24A Cavity plate 24B Base plate 24C, 24D Aperture plate 24E Supply plate 24F, 24G, 24H Manifold plate 24I Cover plate 24J Nozzle plate 25 Piezoelectric actuator substrate 38 Displacement element 40 Supply manifold 41 First connection flow path 42 First squeezing 43 First supply flow path 44 First pressurization chamber 45 First communication flow path 46 First ejection hole 51 Second connection flow path 52 Second squeezing 53 Second supply flow path 54 Second pressurization chamber 55 Second communication flow path 56 Second ejection hole C1 First individual flow path C2 Second individual flow path D1 First direction

Claims

1. A flow path member having a first surface and a second surface located on the opposite side of the first surface, A pressurizing portion located on the first surface, Comprising, The flow path member is, A first discharge hole and a second discharge hole located on the second surface, A first individual flow path connected to the first discharge hole, A first pressurizing chamber located upstream of the first discharge hole in the first individual flow path, A second individual flow path connected to the second discharge hole, A second pressurizing chamber located upstream of the second discharge hole in the second individual flow path, A manifold commonly connected to the upstream side of the first individual flow path and the upstream side of the second individual flow path, Having, The first individual flow path has a first communication flow path connecting the first pressurizing chamber and the first discharge hole, The second individual flow path has a second communication flow path connecting the second pressurizing chamber and the second discharge hole, The second pressurizing chamber is located closer to the manifold than the first pressurizing chamber in a plan view, A liquid discharge head in which at least a part of the width of the second communication flow path is different from the width of the first communication flow path.

2. The liquid discharge head according to claim 1, wherein at least a part of the width of the second communication flow path is larger than the width of the first communication flow path.

3. The liquid discharge head according to claim 2, wherein at least a part of the width of the second communication flow path is 0.5 to 2.5% larger than the width of the first communication flow path.

4. The flow path member has a laminated structure in which a plurality of plates are laminated, The plurality of plates each include a plurality of manifold plates having a plurality of holes for forming the manifold, the first communication flow path, and the second communication flow path, In each of the plurality of manifold plates, the diameter of the hole for forming the second communication flow path is larger than the diameter of the hole for forming the first communication flow path. The liquid discharge head according to claim 2.

5. The liquid discharge head according to claim 4, wherein the thickness of each of the plurality of manifold plates is thicker than other plates included in the plurality of plates.

6. The liquid discharge head according to claim 4, wherein the diameter of the hole for forming the second communication flow path is different between at least one manifold plate of the plurality of manifold plates and other manifold plates.

7. The liquid discharge head according to claim 4, wherein the diameters of the holes for forming the second communication flow path in the plurality of manifold plates are different from each other.

8. When the direction from the first surface toward the second surface is defined as the first direction, The diameter of the holes of the plurality of manifold plates decreases as the position of the holes in the first direction approaches the second surface. The liquid discharge head according to claim 7.

9. The central axes of the holes of the plurality of manifold plates coincide. The liquid discharge head according to claim 6.

10. The plurality of plates are other plates different from the plurality of manifold plates and include other plates having a plurality of holes for forming the first communication flow path and the second communication flow path. In each of the plurality of manifold plates and the other plates, the diameter of the holes for forming the second communication flow path is larger than the diameter of the holes for forming the first communication flow path. The liquid discharge head according to claim 4.

11. A recording apparatus comprising the liquid discharge head according to any one of claims 1 to 10.

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