JP7717964B2 - Liquid ejection head and recording apparatus - Google Patents

Description

The disclosed embodiments relate to a liquid ejection head and a recording device.

Inkjet printers and inkjet plotters are well-known printing devices that use the inkjet recording method. These inkjet printing devices are equipped with a liquid ejection head for ejecting liquid.

Such a liquid ejection head has multiple ejection holes, multiple pressure chambers connected to each of the multiple ejection holes, and a manifold connected to all of the multiple pressure chambers. The multiple pressure chambers include pressure chambers that are relatively far from the manifold and pressure chambers that are relatively close to the manifold (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2005-35291

A liquid ejection head according to one embodiment includes a flow path member having a first surface and a second surface located opposite the first surface, and a pressurizing unit located on the first surface. The flow path member includes first and second ejection holes located on the second surface, a first individual flow path connected to the first ejection holes, a first pressure chamber located upstream of the first ejection holes within the first individual flow path, a second individual flow path connected to the second ejection holes, a second pressure chamber located upstream of the second ejection holes within 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 pressure chamber and the first ejection holes. The second individual flow path has a second communication flow path connecting the second pressure chamber and the second ejection holes. The second pressure chamber is located closer to the manifold than the first pressure chamber in a plan view. The width of at least a portion of the second communication flow path is different from the width of the first communication flow path.

FIG. 1 is a side view that schematically shows a side surface of a printer according to an embodiment. FIG. 2 is a plan view that schematically shows a general plane of the printer according to the embodiment. FIG. 3 is an exploded perspective view showing a schematic configuration of the liquid ejection head according to the embodiment. FIG. 4 is an enlarged plan view of the head main body according to the embodiment. FIG. 5 is a schematic cross-sectional view of the head main body according to the embodiment. FIG. 6 is an enlarged view of the area surrounded by the dashed line shown in FIG. FIG. 7 is a diagram illustrating the variation in the amount of displacement between the first pressurizing chamber and the second pressurizing chamber. FIG. 8 is a diagram illustrating an example of the relationship between the width of the second communication flow path and the ejection speed of the liquid ejected from the second ejection hole. FIG. 9 is a diagram showing specific examples of the diameters of the holes in the manifold plate. FIG. 10 is a schematic cross-sectional view of a head main body according to another embodiment 1. As shown in FIG. FIG. 11 is a schematic cross-sectional view of a head main body according to another embodiment 2. As shown in FIG. FIG. 12 is an enlarged plan view of a head main body according to another embodiment 3. As shown in FIG.

Embodiments of the liquid ejection head and recording device disclosed herein will be described below with reference to the accompanying drawings. Note that the present disclosure is not limited to the embodiments described below. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of each element may differ from reality. Furthermore, there may be parts in which the dimensional relationships and ratios differ between the drawings.

In addition, in the embodiments described below, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "perpendicular," or "parallel" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

<Printer configuration>
An overview of a printer 1, which is an example of a recording apparatus according to an embodiment, will be described using Figures 1 and 2. Figure 1 is a side view that schematically shows a general side surface of the printer 1 according to an embodiment. Figure 2 is a plan view that schematically shows a general plan view of the printer 1 according to an embodiment.

As shown in Figure 1, the printer 1 comprises a paper feed roller 2, a guide roller 3, an applicator 4, a head case 5, a plurality of conveying rollers 6, a plurality of frames 7, a plurality of liquid ejection heads 8, a conveying roller 9, a dryer 10, a conveying roller 11, a sensor unit 12, and a recovery roller 13.

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

The printer 1 records images and characters on the printing paper P by depositing droplets onto the printing paper P. Before use, the printing paper P is wound around the paper feed roller 2 in a state where it can be pulled out. The printer 1 transports the printing paper P from the paper feed roller 2 through the guide roller 3 and the coater 4 into the head case 5.

The applicator 4 applies the coating agent evenly to the printing paper P. This allows the printing paper P to be surface treated, thereby improving the printing quality of the printer 1.

The head case 5 houses multiple transport rollers 6, multiple frames 7, and multiple liquid ejection heads 8. Inside the head case 5, a space is formed that is isolated from the outside, except for some areas that are connected to the outside, such as the area where the printing paper P enters and exits.

At least one of the 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 printing paper P inside the head case 5 to the vicinity of the liquid ejection head 8.

The frame 7 is a rectangular flat plate and is positioned close to and above the printing paper P being transported by the transport rollers 6. As shown in Figure 2, multiple frames 7 (e.g., four) are provided inside the head case 5 with their longitudinal directions perpendicular to the transport direction of the printing paper P. Each of the multiple frames 7 is arranged at a predetermined interval along the transport direction of the printing paper P.

In the following description, the transport direction of the printing paper P will be referred to as the "sub-scanning direction," and the direction perpendicular to the sub-scanning direction and parallel to the printing paper P will be referred to as the "main scanning direction."

The liquid ejection head 8 is supplied with liquid, such as ink, from a liquid tank (not shown). The liquid ejection head 8 ejects the liquid supplied from the liquid tank.

The control unit 14 controls the liquid ejection head 8 based on data such as images and characters, causing it to eject liquid toward the printing paper P. The distance between the liquid ejection head 8 and the printing paper P is, for example, approximately 0.5 to 20 mm.

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 ends in the longitudinal direction. The liquid ejection head 8 is fixed to the frame 7 so that the longitudinal direction is parallel to the main scanning direction.

In other words, 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.

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 printing paper P, for example, in a direction that is approximately perpendicular, and transporting the printing paper P.

As shown in Figure 2, multiple (e.g., five) liquid ejection heads 8 are provided on one frame 7. Figure 2 shows an example in which two liquid ejection heads 8 are arranged in the front and three in the rear in the sub-scanning direction, and the liquid ejection heads 8 are arranged so that the centers of each liquid ejection head 8 do not overlap in the sub-scanning direction.

The head group 8A is made up of multiple liquid ejection heads 8 mounted on one frame 7. The four head groups 8A are positioned along the sub-scanning direction. 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.

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 multiple colors of ink onto the printing paper P, thereby printing a color image on the printing paper P.

In addition, to treat the surface of the printing paper P, a coating agent may be ejected onto the printing paper P from the liquid ejection head 8.

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 printing paper P and the printing area 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.

The printing paper P that has been printed inside the head case 5 is transported outside the head case 5 by the transport rollers 9 and passes through the inside of the dryer 10. The dryer 10 dries the printing paper P that has been printed. The printing paper P that has been dried in the dryer 10 is transported by the transport rollers 11 and collected by the collection rollers 13.

In the printer 1, by drying the printing paper P in the dryer 10, it is possible to prevent the printing paper P that is wound up in a stack on the recovery roller 13 from sticking together or the undried liquid from rubbing against each other.

The sensor unit 12 is composed of a position sensor, a speed sensor, a temperature sensor, etc. Based on information from the sensor unit 12, the control unit 14 can determine the status of each part of the printer 1 and control each part of the printer 1.

The printer 1 described so far has been shown to use printing paper P as the printing target (i.e., recording medium), but the printing target in printer 1 is not limited to printing paper P, and rolls of cloth, etc. may also be used as the printing target.

Furthermore, the above-mentioned printer 1 may transport the printing paper P on a conveyor belt instead of directly. By using a conveyor belt, the printer 1 can print on sheets of paper, cut pieces of cloth, wood, tiles, etc.

Furthermore, the above-mentioned printer 1 may be configured to eject liquid containing conductive particles from the liquid ejection head 8 to print wiring patterns for electronic devices, etc.

The above-mentioned 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.

The above-mentioned printer 1 may also be provided with a cleaning unit that cleans the liquid ejection head 8. The cleaning unit cleans the liquid ejection head 8, for example, by wiping or capping.

The wiping process is a process in which, for example, a flexible wiper is used to rub the surface of the area where the liquid is ejected, such as the second surface 24b (see Figure 3) of the flow path member 24 (see Figure 3), thereby removing liquid that has adhered to the second surface 24b.

Capping is a process for clearing blockages in the first discharge hole 46 (see Figure 5) and the second discharge hole 56 (see Figure 5), for example, by covering the area from which liquid is discharged with a cap and repeatedly discharging liquid. It is performed as follows: First, a cap is placed over the area from which liquid is discharged, for example, the second surface 24b of the flow path member 24 (this process is called capping). This creates a nearly sealed space between the second surface 24b and the cap. Next, liquid is repeatedly discharged into this sealed space. This allows liquid with a higher viscosity than normal and foreign matter that have been clogging the first discharge hole 46 and the second discharge hole 56 to be removed.

<Configuration of Liquid Ejection Head>
FIG. 3 is an exploded perspective view showing a schematic configuration of the liquid ejection head 8 according to the embodiment.

As shown in Figure 3, the liquid ejection head 8 comprises a head main body 20, a reservoir 21, an electrical board 22, and a head cover 23. The head main body 20 also has a flow path member 24, a piezoelectric actuator board 25, a signal transmission unit 26, and a drive IC 27.

The flow path member 24 of the head body 20 is generally flat and has one main surface, the first surface 24a, and a second surface 24b located on the opposite side of the first surface 24a. The first surface 24a has an opening 40a (see Figure 4), and liquid is supplied from the reservoir 21 to the inside of the flow path member 24 through this opening 40a.

The second surface 24b is provided with a plurality of first discharge holes 46 (see Figure 4) and a plurality of second discharge holes 56 (see Figure 4) that discharge liquid onto the printing paper P. A flow path is formed inside the flow path member 24, allowing liquid to flow from the first surface 24a to the second surface 24b. Details of the flow path member 24 will be described later.

The piezoelectric actuator substrate 25 is located on the first surface 24a of the flow path member 24. The piezoelectric actuator substrate 25 has a plurality of displacement elements 38 (see Figure 5). The displacement elements 38 are an example of a pressure applying section. Details of the piezoelectric actuator substrate 25 will be described later.

Two signal transmission units 26 are electrically connected to the piezoelectric actuator substrate 25. Each signal transmission unit 26 includes multiple driving ICs (Integrated Circuits) 27. Note that in Figure 3, one of the signal transmission units 26 is not shown for ease of understanding.

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

The driving IC 27 is mounted on the signal transmission unit 26. The driving IC 27 controls the driving of each displacement element 38 on the piezoelectric actuator substrate 25.

The head body 20 has an ejection surface that ejects liquid and an opposite surface located on the opposite side of the ejection surface. In the following, the 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.

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

An electrical board 22 is erected on the surface of the reservoir 21 opposite the head body 20. Multiple connectors 28 are located at the end of the electrical board 22 facing the reservoir 21. Each connector 28 houses an end of a signal transmission unit 26.

A power supply connector 29 is located at the end of the electrical board 22 opposite the reservoir 21. The electrical board 22 distributes the current supplied from the outside via the connector 29 to the connector 28 and supplies the current to the signal transmission unit 26.

The head cover 23 is located on the opposite side of the head body 20 and covers the signal transmission unit 26 and the electrical board 22. This allows the liquid ejection head 8 to seal the signal transmission unit 26 and the electrical board 22.

The head cover 23 also has an opening 23a. The connector 29 of the electrical board 22 is inserted through this opening 23a so that it is exposed to the outside.

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. This allows heat generated by the drive IC 27 to be dissipated (radiated) from the contact portion on the side surface of the head cover 23.

The liquid ejection head 8 may further include components other than those shown in Figure 3.

<Configuration of head body>
Next, the configuration of the head main body 20 according to the embodiment will be described with reference to Figures 4 to 6. Figure 4 is an enlarged plan view of the head main body 20 according to the embodiment, Figure 5 is a schematic cross-sectional view of the head main body 20 according to the embodiment, and Figure 6 is an enlarged view of the area surrounded by the dashed line shown in Figure 4.

As shown in FIG. 4, the head main 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 pressure chambers 44, a plurality of second pressure 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.

The plurality of first pressurized chambers 44 and the plurality of second pressurized chambers 54 are connected to the supply manifold 40. The plurality of first discharge holes 46 are connected to each of the plurality of first pressurized chambers 44. The plurality of second discharge holes 56 are connected to each of the plurality of second pressurized chambers 54.

The first pressurized chamber 44 and the second pressurized chamber 54 are open to the first surface 24a of the flow path member 24 (see Figure 5). The first surface 24a of the flow path member 24 also has an opening 40a that connects to the supply manifold 40. Liquid is supplied from the reservoir 21 (see Figure 2) into the interior of the flow path member 24 through this opening 40a.

In the example of Figure 4, the head body 20 has four supply manifolds 40 located inside the flow path member 24. The supply manifolds 40 have an elongated shape extending along the longitudinal direction of the flow path member 24, and openings 40a of the supply manifolds 40 are formed on the first surface 24a of the flow path member 24 at both ends.

A plurality of first pressure chambers 44 and a plurality of second pressure chambers 54 are formed in the flow path member 24, spreading out two-dimensionally. The first pressure chambers 44 and the second pressure chambers 54 are hollow regions having a roughly diamond-shaped planar shape with rounded corners. The first pressure chambers 44 and the second pressure chambers 54 open to the first surface 24a of the flow path member 24 and are closed by bonding the piezoelectric actuator substrate 25 to this first surface 24a.

The first pressurized chambers 44 constitute a first pressurized chamber row arranged in the longitudinal direction of the flow path member 24 (supply manifold 40), and the second pressurized chambers 54 constitute a second pressurized chamber row arranged in the longitudinal direction of the flow path member 24 (supply manifold 40). The first pressurized chambers 44 belonging to the first pressurized chamber row and the second pressurized chambers 54 belonging to the second pressurized chamber row adjacent to the first pressurized chamber row are arranged in a staggered pattern.

A single pressure chamber group is formed by two rows of first pressure chambers and two rows of second pressure chambers connected to one supply manifold 40. In the example of Figure 4, the flow path member 24 has four such pressure chamber groups.

In addition, the relative arrangement of the first pressure chamber 44 and the second pressure chamber 54 within each pressure chamber group is the same, and each pressure chamber group is arranged slightly offset in the longitudinal direction.

The first discharge hole 46 and the second discharge hole 56 are positioned in a position that avoids the area of the flow path member 24 that faces the supply manifold 40. In other words, 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.

Furthermore, in plan view, the first discharge holes 46 and the second discharge holes 56 are arranged to fit within the mounting area of the piezoelectric actuator substrate 25. As a group, these first discharge holes 46 and second discharge holes 56 occupy an area of approximately the same size and shape as the piezoelectric actuator substrate 25.

Then, by displacing the displacement element 38 (see Figure 5) of the corresponding piezoelectric actuator substrate 25, droplets are ejected from the first ejection hole 46 and the second ejection hole 56.

As shown in Figure 5, the supply manifold 40 and the first discharge hole 46 are connected by a first connection flow path 41, a first restriction 42, a first supply flow path 43, a first pressure chamber 44, and a first communication flow path 45.

That is, the flow path member 24 has a first individual flow path C1 including a first connecting flow path 41, a first restriction 42, a first supply flow path 43, a first pressurizing chamber 44, and a first communication flow path 45. In the first individual flow path C1, the first connecting flow path 41 is located near the supply manifold 40 in the liquid flow direction, and the first communication flow path 45 is located near the first discharge holes 46.

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 restriction 42 extends in a direction perpendicular to the first direction D1, and the first supply flow path 43 extends in the first direction D1. Furthermore, 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.

Similarly, the supply manifold 40 and the second discharge hole 56 are connected by a second connection flow path 51, a second restriction 52, a second supply flow path 53, a second pressure chamber 54, and a second communication flow path 55.

That is, the flow path member 24 has a second individual flow path C2 including a second connecting flow path 51, a second restriction 52, a second supply flow path 53, a second pressurizing chamber 54, and a second communication flow path 55. In the second individual flow path C2, the second connecting 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 in the liquid flow direction.

The second connection flow path 51 extends in the first direction D1, the second restriction 52 extends in a direction perpendicular to the first direction D1, and the second supply flow path 53 extends in the first direction D1. 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.

The first individual flow path C1 has a first restriction 42 upstream of the first pressurized chamber 44, which is narrower than other parts. Because this first restriction 42 is narrower than other parts of the first individual flow path C1, the flow path resistance is high.

As a result, in this embodiment, the pressure generated in the first pressurized chamber 44 can be prevented from escaping to the supply manifold 40 rather than the first discharge hole 46. Therefore, according to this embodiment, liquid can be efficiently discharged from the first discharge hole 46.

The second individual flow path C2 has a second restriction 52 upstream of the second pressurized chamber 54, which is narrower than other portions. Because the second restriction 52 is narrower than other portions of the second individual flow path C2, the flow path resistance is high.

As a result, in this embodiment, the pressure generated in the second pressurized chamber 54 can be prevented from escaping to the supply manifold 40 rather than the second discharge hole 56. Therefore, according to this embodiment, liquid can be efficiently discharged from the second discharge hole 56.

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

Note that Figure 5 shows an example of the stacked structure of each plate according to the embodiment, and the example shown in Figure 5 does not necessarily have to be limiting. For example, manifold plates 24F, 24G, and 24H may be configured by stacking three or more plates. Also, cover plate 24I may be configured by stacking multiple plates.

A large number of holes are formed in the multiple plates that make up the flow path member 24, and by connecting these holes, a supply manifold 40, a first individual flow path C1 and a second individual flow path C2 are formed inside the flow path member 24.

In an embodiment, the thickness of these plates can be made to be approximately 10 to 300 μm, thereby increasing the precision of the holes formed.

The first individual flow path C1 has a first communication flow path 45 downstream of the first pressurizing chamber 44 that connects the first pressurizing chamber 44 and the first discharge hole 46. Furthermore, the second individual flow path C2 has a second communication flow path 55 downstream of the second pressurizing chamber 54 that connects the second pressurizing chamber 54 and the second discharge hole 56.

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

In the embodiment, as shown in Figures 5 and 6, the width of the second communication flow path 55 is different from the width of the first communication flow path 45. For example, the width of the second communication flow path 55 is larger than the width of the first communication flow path 45.

In the liquid ejection head 8, the second pressure chamber 54, which is relatively closer to the supply manifold 40, has lower rigidity than the first pressure chamber 44, which is relatively far from the supply manifold 40, and is therefore more susceptible to displacement due to pressure from the displacement element 38. As such, variations in the amount of displacement between the first pressure chamber 44 and the second pressure chamber 54 may result in variations in the liquid ejection speed between the first ejection hole 46 and the second ejection hole 56.

Figure 7 is a diagram illustrating the variation in displacement between the first pressure chamber 44 and the second pressure chamber 54. Figure 7 shows the displacement of the first pressure chamber 44 belonging to the first pressure chamber row and the displacement of the second pressure chamber 54 belonging to the second pressure chamber row.

The row numbers shown in Figure 7 indicate the positions of the first and second pressurizing chamber rows in the short direction of the flow path member 24. For example, the eight first pressurizing chamber rows and eight second pressurizing chamber rows shown in Figure 4 are assigned row numbers 1 to 16, starting from the left. Row numbers 1, 4, 5, 8, 9, 12, 13, and 16 correspond to the first pressurizing chamber rows, and row numbers 2, 3, 6, 7, 10, 11, 14, and 15 correspond to the second pressurizing chamber rows. The column numbers shown in Figure 7 indicate the positions of the first pressurizing chambers 44 belonging to the first pressurizing chamber row and the second pressurizing chambers 54 belonging to the second pressurizing chamber row in the long direction of the flow path member 24.

As shown in Figure 7, the second pressurizing chamber 54, which is relatively closer to the supply manifold 40, has a larger displacement amount than the first pressurizing chamber 44, which is relatively farther from the supply manifold 40. In this way, if there is variation in the displacement amount between the first pressurizing chamber 44 and the second pressurizing chamber 54, the second discharge hole 56 connected to the second pressurizing chamber 54 will have a higher liquid discharge speed than the first discharge hole 46 connected to the first pressurizing chamber 44. This impairs the uniformity of the liquid discharge speed between the first discharge hole 46 and the second discharge hole 56.

Therefore, in an embodiment, as shown in Figures 5 and 6, the width of the second communication flow path 55 is made larger than the width of the first communication flow path 45, thereby making the liquid ejection speed between the first ejection hole 46 and the second ejection hole 56 uniform.

Figure 8 is a diagram illustrating an example of the relationship between the width of the second communication flow path 55 and the ejection speed of the liquid ejected from the second ejection hole 56. The inventors varied the width (flow path width) of the second communication flow path 55, supplied liquid to the inside of the flow path member 24, and conducted a simulation to investigate the ejection speed of the liquid ejected from the second ejection hole 56. Figure 8 shows the results of this simulation.

As shown in Figure 8, the discharge speed of the liquid discharged from the second discharge hole 56 reached its maximum when the width of the second communication flow path 55 was approximately 200 μm, and decreased from its maximum value when the width of the second communication flow path 55 was greater or less than approximately 200 μm. When the width of the second communication flow path 55 was small, the flow path resistance of the second communication flow path 55 increased, and the pressure wave generated in the second pressure chamber 54 was not efficiently transmitted to the second discharge hole 56, which is thought to result in a decrease in the discharge speed of the liquid. Furthermore, when the width of the second communication flow path 55 was large, the pressure wave generated in the second pressure chamber 54 was absorbed and attenuated by the liquid, which is thought to result in a decrease in the discharge speed of the liquid. Although not explained here, simulation results similar to those shown in Figure 8 were obtained for the discharge speed of the liquid discharged from the first discharge hole 46 as the width of the first communication flow path 45 changed.

In the liquid ejection head 8, the widths of the first communication flow path 45 and the second communication flow path 55 are generally set so that the ejection speed of the liquid ejected from the ejection holes (first ejection hole 46 and second ejection hole 56) is maximized. For example, in the example shown in Figure 8, the widths of the first communication flow path 45 and the second communication flow path 55 are set to a common set value of approximately 200 μm, which maximizes the ejection speed of the liquid. Setting the widths of the first communication flow path 45 and the second communication flow path 55 to a common set value theoretically should result in no variation in the ejection speed of the liquid between the first ejection hole 46 and the second ejection hole 56. However, as described above, in practice, due to variations in the amount of displacement between the first pressure chamber 44 and the second pressure chamber 54, the ejection speed of the liquid from the second ejection hole 56 is increased compared to the first ejection hole 46. This impairs the uniformity of the ejection speed of the liquid between the first ejection hole 46 and the second ejection hole 56.

In contrast, in the embodiment, the width of the second communication flow path 55 is made larger than the width of the first communication flow path 45, thereby reducing the discharge speed of the liquid discharged from the second discharge hole 56 to approach the discharge speed of the liquid discharged from the first discharge hole 46. 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 improved.

In the embodiment, the width of the second communication flow path 55 is greater than the width of the first communication flow path 45, but the width of the second communication flow path 55 may be smaller than the width of the first communication flow path 45. In short, it is sufficient that the width of the second communication flow path 55 is different from the width of the first communication flow path 45. Furthermore, the overall width of the second communication flow path 55 does not necessarily have to be different from the width of the first communication flow path 45. For example, the width of a portion of the second communication flow path 55 may be different from the width of the first communication flow path 45, and the width of another portion of the second communication flow path 55 may be the same as the width of the first communication flow path 45. In short, it is sufficient that the width of at least a portion of the second communication flow path 55 is different from the width of the first communication flow path 45.

In addition, in the embodiment, the width of the second communication flow path 55 is preferably 0.5 to 2.5% larger than the width of the first communication flow path 45. For example, when the width of the first communication flow path 45 is approximately 200 μm, the width of the second communication flow path 55 is preferably approximately 1 to 5 μm larger than the width of the first communication flow path 45. This makes it possible to prevent the ejection speed of the liquid ejected from the second ejection hole 56 from decreasing excessively. Therefore, according to the embodiment, the uniformity of the ejection speed of the liquid between the first ejection hole 46 and the second ejection hole 56 can be further improved.

In addition, in an embodiment, as shown in Figure 5, in each of the manifold plates 24F, 24G, and 24H, the diameter r2 of the hole for forming the second communication flow path 55 is preferably larger than the diameter r1 of the hole for forming the first communication flow path 45.

Figure 9 shows specific examples of hole diameters in the manifold plate 24H. Figure 9 shows the diameter r1 of the hole for forming the first communication flow path 45 and the diameter r2 of the hole for forming the second communication flow path 55. The row numbers in Figure 9 indicate the positions of the holes for forming the first communication flow path 45 and the holes for forming the second communication flow path 55 in the short direction of the flow path member 24. The same numbers as the row numbers of the corresponding first pressure chamber row and second pressure chamber row are assigned to these holes. Row numbers 1, 4, 5, 8, 9, 12, 13, and 16 correspond to the holes for forming the first communication flow path 45, and row numbers 2, 3, 6, 7, 10, 11, 14, and 15 correspond to the holes for forming the second communication flow path 55. As shown in Figure 9, in the manifold plate 24H, 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. Although not described here, in each of the manifold plates 24F, 24G, 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. That is, in each of the manifold plates 24F, 24G, 24H, 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. As a result, by stacking the manifold plates 24F, 24G, 24H in position so that the holes communicate with each other, the first communication flow path 45 and the second communication flow path 55 can be easily formed in the flow path member 24.

In addition, in the embodiment, as shown in FIG. 5, the thickness of each of the manifold plates 24F, 24G, and 24H may be thicker than the other plates included in the multiple 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 thicker than the other plates, such as the cavity plate 24A. By making the thickness of each of the manifold plates 24F, 24G, and 24H thicker than the other plates, the volume of the second communication flow paths 55 in the manifold plates 24F, 24G, and 24H can be made larger than the volume of the second communication flow paths 55 in the other plates. This allows pressure waves generated in the second pressure chamber 54 to be absorbed and efficiently attenuated by the liquid in the second communication flow paths 55 in the manifold plates 24F, 24G, and 24H, thereby expanding the adjustment range of the discharge velocity of the liquid discharged from the second discharge holes. Therefore, according to the embodiment, the uniformity of the liquid discharge velocity between the first discharge holes 46 and the second discharge holes 56 can be further improved.

In addition, in the embodiment, as shown in FIG. 5, the diameter r2 of the hole forming the second communication flow path 55 in each of the manifold plates 24F, 24G, and 24H and other plates may be larger than the diameter r1 of the hole forming the first communication flow path 45. For example, in each of the base plate 24B, aperture plates 24C and 24D, supply plate 24E, and cover plate 24I, the diameter r2 of the hole forming the second communication flow path 55 is larger than the diameter r1 of the hole forming the first communication flow path 45. This allows for an increase in the volume of the second communication flow path 55 not only in the manifold plates 24F, 24G, and 24H but also in the other plates. As a result, pressure waves generated in the second pressure chamber 54 are absorbed and efficiently attenuated by the liquid in the second communication flow path 55 in the manifold plates 24F, 24G, and 24H and other plates, thereby widening the adjustment range of the discharge speed of the liquid discharged from the second discharge hole 56. Therefore, according to the embodiment, the uniformity of the liquid ejection speed between the first ejection holes 46 and the second ejection holes 56 can be further improved.

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

In addition, the piezoelectric actuator substrate 25 has a piezoelectric ceramic layer 25B, a common electrode 33, a piezoelectric ceramic layer 25A, and an individual electrode 34 stacked in this order.

The piezoelectric ceramic layers 25A and 25B each extend across multiple first pressure chambers 44 and second pressure chambers 54. Each of the piezoelectric ceramic layers 25A and 25B has a thickness of approximately 20 μm. The piezoelectric ceramic layers 25A and 25B are made of, for example, a ferroelectric ceramic material such as lead zirconate titanate (PZT).

The common electrode 33 is formed over almost the entire surface of the region between the piezoelectric ceramic layer 25A and the piezoelectric ceramic layer 25B. In other words, the common electrode 33 overlaps with all of the first pressure chambers 44 and second pressure chambers 54 within the region facing the piezoelectric actuator substrate 25.

The thickness of the common electrode 33 is approximately 2 μm. The common electrode 33 is made of a metal material such as an Ag-Pd system.

The individual electrodes 34 include a main electrode 34a and an extraction electrode 34b. The main electrode 34a is located on the piezoelectric ceramic layer 25A in an area facing the first pressure chamber 44 and the second pressure chamber 54. The main electrode 34a is slightly smaller than the first pressure chamber 44 and the second pressure chamber 54, and has a shape that is roughly similar to the first pressure chamber 44 and the second pressure chamber 54.

The extraction electrode 34b is extended from the main electrode 34a to outside the area 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.

The connection electrode 35 is located on the extraction electrode 34b and is formed in a convex shape with a thickness of approximately 15 μm. The connection electrode 35 is also electrically connected to an electrode provided in the signal transmission unit 26 (see Figure 3). The connection electrode 35 is made of, for example, silver-palladium containing glass frit.

The dummy electrode 36 is located on the piezoelectric ceramic layer 25A so as not to overlap with various electrodes such as the individual electrode 34. The dummy electrode 36 connects the piezoelectric actuator substrate 25 and the signal transmission section 26, increasing the connection strength.

The dummy electrodes 36 also uniformly distribute the contact positions between the piezoelectric actuator substrate 25 and the signal transmission section 26, stabilizing the electrical connection. The dummy electrodes 36 are preferably made of the same material as the connection electrodes 35 and are preferably formed using the same process as the connection electrodes 35.

The surface electrode 37 shown in Figure 4 is formed on the piezoelectric ceramic layer 25A in a position that avoids the individual electrodes 34. The surface electrode 37 is connected to the common electrode 33 through a via hole formed in the piezoelectric ceramic layer 25A.

As a result, the surface electrode 37 is grounded and maintained at ground potential. The surface electrode 37 is preferably made of the same material as the individual electrodes 34 and is preferably formed using the same process as the individual electrodes 34.

To individually control the potential of each of the multiple individual electrodes 34, each is electrically connected to the control unit 14 (see Figure 1) via the signal transmission unit 26 and wiring. When the individual electrodes 34 and the common electrode 33 are set to different potentials and an electric field is applied in the polarization direction of the piezoelectric ceramic layer 25A, the portion of the piezoelectric ceramic layer 25A to which the electric field is applied operates as an active portion that distorts due to the piezoelectric effect.

In other words, on the piezoelectric actuator substrate 25, the individual electrodes 34, the piezoelectric ceramic layers 25A, 25B, and the portions of the common electrode 33 that face the first pressure chamber 44 and the second pressure chamber 54 function as displacement elements 38.

When the displacement element 38 undergoes unimorph deformation, the first pressure chamber 44 and the second pressure chamber 54 are pressed, and liquid is ejected from the first ejection hole 46 and the second ejection hole 56.

Next, the driving procedure for the liquid ejection head 8 according to the embodiment will be explained. The individual electrodes 34 are set in advance to a higher potential (hereinafter also referred to as a high potential) than the common electrode 33. Then, each time an ejection request is received, the control unit 14 temporarily sets the individual electrodes 34 to the same potential as the common electrode 33 (hereinafter also referred to as a low potential), and then sets them to a high potential again at a predetermined timing.

As a result, when the individual electrode 34 becomes low potential, the piezoelectric ceramic layers 25A, 25B return to their original shape, and the volume of the first pressure chamber 44 and the second pressure chamber 54 increases compared to their initial state, i.e., the high potential state.

At this time, negative pressure is applied to the first pressure chamber 44 and the second pressure chamber 54, causing the liquid in the supply manifold 40 to be sucked into the first pressure chamber 44 and the second pressure chamber 54.

Then, when the individual electrode 34 is again set to a high potential, the piezoelectric ceramic layers 25A, 25B deform so as to become convex toward the first pressure chamber 44 and the second pressure chamber 54.

In other words, as the volume of the first pressure chamber 44 and the second pressure chamber 54 decreases, the pressure inside the first pressure chamber 44 and the second pressure chamber 54 becomes positive. This increases the pressure of the liquid inside the first pressure chamber 44 and the second pressure chamber 54, causing droplets to be ejected from the first ejection hole 46 and the second ejection hole 56.

In other words, the control unit 14 supplies a drive signal including a pulse based on a high potential to the individual electrode 34 to eject droplets from the first ejection hole 46 and the second ejection hole 56. The pulse width may be set to the acoustic length (AL), which is the length of time it takes for a pressure wave to propagate from the first connection flow path 41 to the first ejection hole 46 (or from the second connection flow path 51 to the second ejection hole 56).

As a result, when the pressure inside the first pressure chamber 44 and the second pressure chamber 54 reverses from a negative pressure state to a positive pressure state, the pressures inside the two chambers combine, allowing droplets to be ejected with stronger pressure.

In addition, in gradation printing, gradation is expressed by the number of droplets continuously ejected from the first ejection hole 46 and the second ejection hole 56, i.e., the droplet amount (volume) is adjusted by the number of droplet ejections. Therefore, droplets are continuously ejected the number of times corresponding to the specified gradation expression from the first ejection hole 46 and the second ejection hole 56 corresponding to the specified dot area.

Generally, when liquid is continuously ejected, the interval between pulses supplied to eject droplets may be set to AL. This ensures that the period of the residual pressure wave generated when ejecting a previously ejected droplet matches the period of the pressure wave generated when ejecting a subsequent droplet.

As a result, the residual pressure wave and the pressure wave overlap, amplifying the pressure required to eject droplets. In this case, the speed of the droplets ejected later increases, and the impact points of multiple droplets become closer.

<Embodiments of Various Types of Head Main Body>
Each type of head main body 20 according to the embodiment will be described with reference to Figures 10 to 12. Figure 10 is a schematic cross-sectional view of the head main body 20 according to another embodiment 1.

In addition, in the various embodiments below, parts that are the same as those in the embodiments will be given the same symbols, and duplicate explanations will be omitted.

As shown in FIG. 10 , in another embodiment 1, the diameter of the holes forming the second communication flow paths 55 in at least one of the manifold plates 24F, 24G, and 24H is different from that in the other manifold plates. For example, the diameter r21 of the holes forming the second communication flow paths 55 in the manifold plates 24F and 24G is larger than the diameter r22 of the holes forming the second communication flow paths 55 in the manifold plates 24H. This allows for fine adjustment of the volume of the second communication flow paths 55 in the manifold plates 24F, 24G, and 24H, thereby widening the adjustment range for the ejection speed of the liquid ejected from the second ejection holes 56. Therefore, according to another embodiment 1, the uniformity of the ejection speed of the liquid between the first ejection holes 46 and the second ejection holes 56 can be further improved.

In another embodiment 1, the central axes of the holes (holes for forming the second communication flow paths 55) in the manifold plates 24F, 24G, and 24H are aligned. This allows liquid to flow along the central axes of the holes (holes for forming the second communication flow paths 55) in the manifold plates 24F, 24G, and 24H, even if the diameters of the holes are different. Therefore, according to another embodiment 1, turbulence in the flow of liquid in the second communication flow paths 55 can be suppressed.

Figure 11 is a schematic cross-sectional view of a head body 20 relating to another embodiment 2.

As shown in Figure 11, in another embodiment 2, the manifold plates 24F, 24G, and 24H have different diameters for the holes that form the second communication flow paths 55. This allows for fine adjustment of the volume of the second communication flow paths 55 in the manifold plates 24F, 24G, and 24H, thereby widening the range of adjustment for the ejection speed of the liquid ejected from the second ejection holes 56. Therefore, according to another embodiment 2, the uniformity of the ejection speed of the liquid between the first ejection holes 46 and the second ejection holes 56 can be further improved.

In another embodiment 2, the diameters of the holes (holes for forming the second communication flow paths 55) in the manifold plates 24F, 24G, and 24H become smaller as the position of the holes (holes for forming the second communication flow paths 55) in the first direction D1 approaches the second surface 24b. That is, the diameter r22 of the holes in the manifold plate 24G is smaller than the diameter r21 of the holes in the manifold plate 24F, and the diameter r23 of the holes in the manifold plate 24H is smaller than the diameter r22 of the holes in the manifold plate 24G. This allows the volume of the second communication flow paths 55 in the manifold plates 24F, 24G, and 24H to gradually decrease toward the downstream side of the liquid, thereby increasing the flow velocity of the liquid in the second communication flow paths 55 as it approaches the second discharge holes 56. Therefore, according to another embodiment 2, the discharge of air and foreign matter from the second discharge holes 56 can be facilitated.

Furthermore, in Alternative Embodiment 2, similar to Alternative Embodiment 1, the central axes of the holes (holes for forming the second communication flow path 55) in the manifold plates 24F, 24G, and 24H are aligned. Therefore, according to Alternative Embodiment 2, similar to Alternative Embodiment 1, turbulence in the flow of liquid within the second communication flow path 55 can be suppressed.

Figure 12 is an enlarged plan view of the head body 20 relating to another embodiment 3.

As shown in Figure 12, in the flow path member 24 of the head main body 20 according to another embodiment 3, the position of the first pressurizing chamber 44 differs from that of the embodiment. Specifically, in a plan view, the first pressurizing chamber 44 is positioned closer to the supply manifold 40 overall than in the embodiment, and has a portion that overlaps with the supply manifold 40.

In another embodiment 3, the area of the portion of the first pressurized chamber 44 that overlaps with the supply manifold 40 is smaller than the area of the portion of the second pressurized chamber 54 that overlaps with the supply manifold 40 in a plan view. This allows the first pressurized chamber 44 and the second pressurized chamber 54 to be arranged with efficient space utilization within the flow path member 24. Therefore, according to another embodiment 3, the flow path member 24 can be made smaller, and therefore the head main body 20 can be made smaller.

The above describes an embodiment of the present disclosure, but the present disclosure is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present disclosure. For example, in the above embodiment, an example was shown in which the flow path member 24 was composed of multiple stacked plates, but the flow path member 24 is not limited to being composed of multiple stacked plates.

For example, the flow path member 24 may be constructed by forming the supply manifold 40, the first individual flow path C1, the second individual flow path C2, etc. by etching.

As described above, the liquid ejection head (e.g., liquid ejection head 8) according to the embodiment comprises 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 opposite the first surface, and a pressure applying section (e.g., displacement element 38) located on the first surface. The flow path member has a first discharge hole (e.g., first discharge hole 46) and a second discharge hole (e.g., second discharge hole 56) located on the second surface, a first individual flow path (e.g., first individual flow path C1) connected to the first discharge hole, a first pressurizing chamber (e.g., first pressurizing chamber 44) located upstream of the first discharge hole in the first individual flow path, a second individual flow path (e.g., second individual flow path C2) connected to the second discharge hole, a second pressurizing chamber (e.g., second pressurizing chamber 54) located upstream of the second discharge hole in the second individual flow path, and a manifold (e.g., supply manifold 40) 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 (e.g., first communication flow path 45) connecting the first pressurizing chamber and the first discharge hole. The second individual flow path has a second communication flow path (for example, second communication flow path 55) that connects the second pressure chamber and the second ejection hole. In a plan view, the second pressure chamber is located closer to the manifold than the first pressure chamber. The width of at least a portion of the second communication flow path is different from the width of the first communication flow path. As a result, the liquid ejection head according to the embodiment can improve the uniformity of the liquid ejection speed.

Furthermore, the width of at least a portion of the second communication flow path may be greater than the width of the first communication flow path. As a result, with the liquid ejection head according to the embodiment, the ejection speed of the liquid ejected from the second ejection holes can be reduced to approach the ejection speed of the liquid ejected from the first ejection holes, thereby improving the uniformity of the ejection speed of the liquid.

Furthermore, the width of at least a portion of the second communication flow path may be 0.5 to 2.5% larger than the width of the first communication flow path. As a result, the liquid ejection head according to the embodiment can prevent the ejection speed of the liquid ejected from the second ejection holes from decreasing excessively, thereby further improving the uniformity of the ejection speed of the liquid.

The flow path member may also have a laminated structure in which multiple plates are stacked. The multiple plates may include multiple manifold plates (e.g., manifold plates 24F, 24G, and 24H), each having multiple holes for forming a manifold, a first communication flow path, and a second communication flow path. In each of the multiple manifold plates, the diameter of the hole for forming the second communication flow path (e.g., diameter r2) may be larger than the diameter of the hole for forming the first communication flow path (e.g., diameter r1). As a result, with the liquid ejection head according to the embodiment, the first communication flow path and the second communication flow path can be easily formed within the flow path member by stacking multiple manifold plates in alignment so that their respective holes are in communication with each other.

Furthermore, the thickness of each of the multiple manifold plates may be thicker than the other plates included in the multiple plates. As a result, with the liquid ejection head according to the embodiment, pressure waves generated in the second pressure chambers are absorbed by the liquid in the second communication flow paths in the multiple manifold plates and are efficiently attenuated, thereby widening the range of adjustment for the ejection speed of the liquid ejected from the second ejection holes.

Furthermore, the diameter of the holes forming the second communication flow paths may be different between at least one of the multiple manifold plates and the other manifold plates. This allows the liquid ejection head according to the embodiment to finely adjust the volume of the second communication flow paths in the multiple manifold plates, thereby expanding the range of adjustment for the ejection speed of the liquid ejected from the second ejection holes.

Furthermore, the multiple manifold plates may have different diameters of holes for forming the second communication flow paths. As a result, according to the liquid ejection head of the embodiment, the volume of the second communication flow paths in the multiple manifold plates can be finely adjusted, thereby widening the range of adjustment for the ejection speed of the liquid ejected from the second ejection holes.

Furthermore, when the direction from the first surface toward the second surface is defined as the first direction (for example, first direction D1), the diameter of the holes in the multiple manifold plates may become smaller as the position of the hole in the first direction approaches the second surface. This allows the liquid ejection head according to the embodiment to promote the expulsion of air and foreign matter from the second ejection holes.

In addition, the central axes of the holes in the multiple manifold plates may be aligned. This allows the liquid ejection head according to the embodiment to suppress turbulence in the flow of liquid within the second communication channel.

The multiple plates may also include other plates different from the multiple manifold plates, having multiple holes for forming the first and second communication channels (e.g., base plate 24B, aperture plates 24C and 24D, supply plate 24E, and cover plate 24I). In each of the multiple 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. As a result, with the liquid ejection head according to the embodiment, the pressure wave generated in the second pressure chamber is absorbed and attenuated by the liquid in the second communication channels in the multiple manifold plates and the other plates, thereby widening the adjustment range of the ejection speed of the liquid ejected from the second ejection hole.

Further advantages and alternative embodiments may readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

1 Printer 8 Liquid ejection head 14 Control unit 20 Head main 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 restriction 43 First supply flow path 44 First pressure chamber 45 First communication flow path 46 First discharge hole 51 Second connection flow path 52 Second restriction 53 Second supply flow path 54 Second pressure chamber 55 Second communication flow path 56 Second discharge hole C1 First individual flow path C2 Second individual flow path D1 First direction

Claims (11)

a flow path member having a first surface and a second surface located opposite to the first surface;
a pressure applying portion located on the first surface;
Equipped with
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;
and
the first individual flow path includes a first communication flow path that connects the first pressurizing chamber and the first discharge hole,
the second individual flow path includes a second communication flow path that connects 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 ejection head, wherein the width of at least a part of the second communication flow path is different from the width of the first communication flow path. The liquid ejection head according to claim 1, wherein the width of at least a portion of the second communication flow path is greater than the width of the first communication flow path. A liquid ejection head according to claim 2, wherein the width of at least a portion of the second communication flow path is 0.5 to 2.5% larger than the width of the first communication flow path. the flow path member has a laminated structure in which a plurality of plates are stacked,
the plurality of plates include a plurality of manifold plates each having a plurality of holes for forming the manifold, the first communication flow path, and the second communication flow path;
3. The liquid ejection head according to claim 2, wherein 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. A liquid ejection head as described in claim 4, wherein the thickness of each of the plurality of manifold plates is greater than the other plates included in the plurality of plates. 5. The liquid ejection head according to claim 4, wherein at least one of the plurality of manifold plates has holes for forming the second communication flow paths that have different diameters from the other manifold plates. The liquid ejection head according to claim 4 , wherein the plurality of manifold plates have holes for forming the second communication flow paths with different diameters. When a direction from the first surface toward the second surface is defined as a first direction,
The liquid ejection head according to claim 7 , wherein the diameter of the holes in the plurality of manifold plates decreases as the position of the holes in the first direction approaches the second surface. The liquid ejection head according to claim 6 , wherein the central axes of the holes of the plurality of manifold plates are aligned. the plurality of plates includes another plate different from the plurality of manifold plates, the other plate having a plurality of holes for forming the first communication flow path and the second communication flow path;
5. The liquid ejection head according to claim 4, wherein in each of the plurality of manifold plates and the other plate, 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. A recording device equipped with the liquid ejection head described in any one of claims 1 to 10.