JP7389089B2 - Liquid ejection head and recording device using it - Google Patents

Description

The present invention relates to a liquid ejection head and a recording apparatus using the same.

2. Description of the Related Art Conventionally, as a printing head, for example, a liquid ejection head that performs various kinds of printing by ejecting liquid onto a recording medium is known. The liquid ejection head includes, for example, an ejection hole that ejects liquid, a pressurization chamber that pressurizes the liquid so that the liquid is ejected from the ejection hole, a first common channel that supplies liquid to the pressurization chamber, and a pressurization chamber that pressurizes the liquid so that the liquid is ejected from the ejection hole. A device is known that includes a second common flow path for recovering liquid from a pressure chamber. In order to prevent clogging of the flow path due to liquid accumulation, the liquid flows from the first common flow path through the pressurizing chamber to the second common flow path even when no discharge is performed. It is known that the liquid is circulated, including the outside. Further, in such a liquid ejection head, the plurality of first common channels and the plurality of second common channels are shaped to extend in the width direction of the liquid ejection head, and are arranged alternately in the longitudinal direction of the liquid ejection head. (For example, see Patent Document 1.)

Japanese Patent Application Publication No. 2009-143168

In the liquid ejection head as described in Patent Document 1, the pressurizing chamber connected to the first common flow path or the second common flow path located at the longitudinal end of the liquid ejection head is Compared to a pressurized chamber located in the longitudinal center of the pressurized chamber, it is more susceptible to the influence of the temperature of the external environment. Liquid characteristics (e.g. viscosity) basically have temperature characteristics, so if there is a temperature difference in the liquid in the pressurized chamber, the discharge characteristics (discharge amount and discharge speed) of the liquid discharged from the pressurized chamber will change. There is a problem in that the recording accuracy deteriorates because of the difference in .

Therefore, an object of the present invention is to provide a liquid ejection head that can reduce the temperature difference within the liquid ejection head, and a recording apparatus using the same.

The liquid ejection head of the present invention includes a first channel member having a plurality of ejection holes and a plurality of pressure chambers respectively connected to the plurality of ejection holes, and a first flow path member that collects liquid from the plurality of pressurization chambers. a second flow path member stacked on the first flow path member, the second flow path member having a first integrated flow path and a second integrated flow path that supplies liquid to the plurality of pressurization chambers; and the plurality of pressurization chambers. The liquid ejection head includes a plurality of pressurizing parts that respectively pressurize, and when viewed in plan, the plurality of pressurizing chambers are arranged in a pressurizing chamber arrangement area, and the first integrated flow The path is arranged in a first direction relative to the pressurization chamber arrangement area, extends in a second direction intersecting the first direction, and is arranged in the second direction relative to the pressurization chamber arrangement area. the second integrated flow path is arranged in a third direction opposite to the first direction, with respect to the pressurization chamber arrangement region; and a second end flow path extending in a fourth direction opposite to the two directions and disposed further in the fourth direction than the pressurizing chamber arrangement area, Is the first flow path member and the second flow path member joined to each other below one end, or is the upper surface of the first flow path member a lower surface of the first end? Either the first flow path member and the second flow path member are joined below the second end, or the upper surface of the first flow path member is above the second end. It is characterized by having either a lower surface or a lower surface.

Further, the liquid ejection head of the present invention includes a plurality of ejection holes, a plurality of pressurizing chambers respectively connected to the plurality of ejection holes, a first integrated flow path for recovering liquid from the plurality of pressurizing chambers, and a plurality of the plurality of pressurizing chambers. A liquid ejection head including a flow path member having a second integrated flow path for supplying liquid to the pressurization chambers, and a plurality of pressurizing parts that pressurize the plurality of pressurization chambers, respectively, the liquid ejection head shown in FIG. At this time, the plurality of pressurizing chambers are arranged in a pressurizing chamber arrangement region, and the first integrated flow path is arranged in a first direction than the pressurizing chamber arrangement region in a plane. and a first end flow path extending in a second direction intersecting the first direction and disposed further in the second direction than the pressurizing chamber arrangement area, The two integrated flow paths are arranged in a third direction opposite to the first direction from the pressurization chamber arrangement area, and extend in a fourth direction opposite to the two directions, Further, it is characterized in that it includes a second end flow path arranged in the fourth direction with respect to the pressurization chamber arrangement region.

Furthermore, the recording apparatus of the present invention is characterized in that it includes the liquid ejection head, a conveyance section that conveys a recording medium to the liquid ejection head, and a control section that controls the liquid ejection head.

According to the liquid ejection head of the present invention, the temperature difference within the liquid ejection head can be reduced.

(a) is a side view of a recording device including a liquid ejection head according to an embodiment of the present invention, and (b) is a plan view. (a) is a plan view of the head main body which is a main part of the liquid ejection head of FIG. 1, and (b) is a plan view from (a) with the second flow path member removed. It is an enlarged plan view of a part of FIG.2(b). It is an enlarged plan view of a part of FIG.2(b). (a) is a partial vertical sectional view taken along the line VV in FIG. 4, and (b) is a partial vertical sectional view of the head main body in FIG. 2(a). 2(a) is a schematic plan view of FIG. 2(a), and FIGS. 2(b) and 2(c) are schematic plan views of a liquid ejection head according to another embodiment of the present invention. (a) to (c) are schematic plan views of a liquid ejection head according to another embodiment of the present invention.

FIG. 1(a) is a schematic side view of a (color inkjet) printer 1, which is a recording device including a liquid ejection head 2 according to an embodiment of the present invention, and FIG. 1(b) is a schematic plan view. It is. The printer 1 moves the printing paper P, which is a recording medium, relative to the liquid ejection head 2 by transporting the printing paper P from the transport roller 80A to the transport roller 80B. The control unit 88 controls the liquid ejection head 2 based on image and character data to eject liquid toward the recording medium P, make droplets land on the printing paper P, and print on the printing paper P. etc. will be recorded.

In this embodiment, the liquid ejection head 2 is fixed to the printer 1, and the printer 1 is a so-called line printer. As another embodiment of the recording apparatus of the present invention, an operation of moving the liquid ejection head 2 by reciprocating in a direction intersecting the conveying direction of the printing paper P, for example, a direction substantially perpendicular to the conveyance direction of the printing paper P; An example of this is a so-called serial printer, which alternately transports images.

A flat (head-mounted) frame 70 is fixed to the printer 1 so as to be substantially parallel to the printing paper P. The frame 70 is provided with 20 holes (not shown), 20 liquid ejection heads 2 are mounted in each hole, and the portion of the liquid ejection head 2 that ejects liquid is connected to the printing paper P. It is designed to face. The distance between the liquid ejection head 2 and the printing paper P is, for example, about 0.5 to 20 mm. The five liquid ejection heads 2 constitute one head group 72, and the printer 1 has four head groups 72.

The liquid ejection head 2 has an elongated shape that is elongated in the direction from the front to the back in FIG. 1(a) and in the vertical direction in FIG. 1(b). This long direction is sometimes called the longitudinal direction. In one head group 72, the three liquid ejection heads 2 are lined up in a direction that intersects the conveyance direction of the printing paper P, for example, in a direction that is almost perpendicular to the conveyance direction, and the other two liquid ejection heads 2 One each is lined up between the three liquid ejection heads 2 at positions shifted along the direction. The liquid ejection heads 2 are arranged so that the range that can be printed by each liquid ejection head 2 is connected in the width direction of the printing paper P (in a direction crossing the conveyance direction of the printing paper P), or so that the edges thereof overlap. This makes it possible to print without gaps in the width direction of the printing paper P.

The four head groups 72 are arranged along the conveyance direction of the recording paper P. Each liquid ejection head 2 is supplied with liquid (ink) from a liquid tank (not shown). The liquid ejection heads 2 belonging to one head group 72 are supplied with ink of the same color, and the four head groups can print with four colors of ink. The colors of ink ejected from each head group 72 are, for example, magenta (M), yellow (Y), cyan (C), and black (K). If such ink is controlled and printed by the control unit 88, a color image can be printed.

The number of liquid ejection heads 2 mounted on the printer 1 may be one as long as the printable range with one liquid ejection head 2 is printed in a single color. The number of liquid ejection heads 2 included in the head group 72 and the number of head groups 72 can be changed as appropriate depending on the object to be printed and printing conditions. For example, the number of head groups 72 may be increased to print in more colors. Further, by arranging a plurality of head groups 72 that print in the same color and printing alternately in the transport direction, the printing speed (transport speed) can be increased. Alternatively, a plurality of head groups 72 that print in the same color may be prepared and arranged so as to be shifted in a direction intersecting the transport direction to increase the resolution in the width direction of the printing paper P.

Furthermore, in addition to printing colored ink, a liquid such as a coating agent may be printed to treat the surface of the printing paper P.

The printer 1 prints on printing paper P, which is a recording medium. The printing paper P is wound around the paper feed roller 80A, passes between the two guide rollers 82A, passes under the liquid ejection head 2 mounted on the frame 70, and then It passes between two transport rollers 82B and is finally collected by collection roller 80B. When printing, the printing paper P is transported at a constant speed by rotating the transport roller 82B, and printed by the liquid ejection head 2. Collection roller 80B winds up printing paper P sent out from conveyance roller 82B. The conveyance speed is, for example, 50 m/min. Each roller may be controlled by the control unit 88 or may be manually operated by a person.

In addition to printing paper P, the recording medium may be cloth or the like. In addition, the printer 1 is configured to convey a conveyor belt instead of the printing paper P, and the recording medium may be sheet paper, cut cloth, wood, etc. placed on the conveyor belt in addition to roll-shaped recording media. It may also be made of tiles. Furthermore, a wiring pattern of an electronic device or the like may be printed by ejecting a liquid containing conductive particles from the liquid ejection head 2. Furthermore, a chemical agent may be produced by ejecting a predetermined amount of a liquid chemical agent or a liquid containing a chemical agent from the liquid ejecting head 2 toward a reaction container or the like to cause a reaction.

Alternatively, a position sensor, a speed sensor, a temperature sensor, etc. may be attached to the printer 1, and the control unit 88 may control each part of the printer 1 according to the state of each part of the printer 1 as determined from information from each sensor. In particular, if the ejection characteristics (e.g. ejection amount and ejection speed) of the liquid ejected from the liquid ejection head 2 are affected by external factors, the temperature of the liquid ejection head 2, the temperature of the liquid in the liquid tank, the temperature of the liquid tank, The drive signal for causing the liquid ejection head 2 to eject the liquid may be changed depending on the pressure applied to the liquid ejection head 2 by the liquid.

Next, a liquid ejection head 2 according to an embodiment of the present invention will be described. FIG. 2(a) is a plan view showing a head main body 2a, which is a main part of the liquid ejection head 2 shown in FIG. FIG. 2(b) is a plan view of the head main body 2a with the second flow path member 6 removed. 3 and 4 are enlarged plan views of FIG. 2(b). FIG. 5(a) is a longitudinal cross-sectional view taken along line VV in FIG. 4. FIG. 5(b) is a partial vertical cross-sectional view along the first common flow path 20 in the vicinity of the opening 20a of the first common flow path 20 of the head main body 2a. FIG. 6(a) is a schematic plan view of the head main body 2a shown in FIG. 2(a).

Each figure is drawn as follows to make the drawings easier to understand. In FIGS. 2 to 4, channels that are below other objects and should be drawn with broken lines are drawn with solid lines. In FIG. 2A, most of the flow paths in the first flow path member 4 are omitted, and only the arrangement of the pressurizing chambers 10 is shown.

The liquid ejection head 2 may include a metal housing, a driver IC, a wiring board, etc. in addition to the head main body 2a. The head body 2a also includes a first flow path member 4, a second flow path member 6 that supplies liquid to the first flow path member 4, and a piezoelectric actuator in which a displacement element 50 serving as a pressurizing section is built. A substrate 40 is included. The head main body 2a has a flat plate shape that is long in one direction, and this direction is sometimes referred to as a longitudinal direction. Further, the second flow path member 6 serves as a support member, and the head main body 2a is fixed to the frame 70 at each of both ends of the second flow path member 6 in the longitudinal direction.

The first channel member 4 constituting the head main body 2a has a flat plate shape, and has a thickness of about 0.5 to 2 mm. On the pressurizing chamber surface 4-1, which is the first main surface of the first flow path member 4, a large number of pressurizing chambers 10 are arranged side by side in the plane direction. On the discharge hole surface 4-2, which is the second main surface of the first flow path member 4, a large number of discharge holes 8 through which liquid is discharged are arranged side by side in the plane direction. The discharge holes 8 are each connected to a pressurizing chamber 10. In the following description, it is assumed that the pressurizing chamber surface 4-1 is located above the discharge hole surface 4-2.

A plurality of first common channels 20 and a plurality of second common channels 24 are arranged in the first channel member 4 so as to extend along the first direction. Further, the first common flow path 20 and the second common flow path 24 are arranged alternately in the second direction, which is a direction intersecting the first direction.

The pressurizing chambers 10 are lined up along both sides of the first common channel 20, forming a total of two pressurizing chamber rows 11A, one on each side. The first common flow path 20 and the pressurizing chambers 10 arranged on both sides thereof are connected via the first individual flow path 12.

The pressurizing chambers 10 are lined up along both sides of the second common flow path 24, forming a total of two pressurizing chamber rows 11A, one on each side. The first integrated channel 22 and the pressurizing chambers 10 arranged on both sides thereof are connected via a second individual channel 14. In addition, below, the 1st common flow path 20 and the 2nd common flow path 24 may be collectively called a common flow path.

In other words, the pressurizing chambers 10 are arranged side by side on an imaginary line, the first common flow path 20 extends along one side of the imaginary line, and the first common flow path 20 extends along the other side of the imaginary line. A second common flow path 24 extends therethrough. In this embodiment, the virtual line along which the pressurizing chambers 10 are lined up is a straight line, but it may also be a curved line or a polygonal line.

With the above configuration, in the first flow path member 4, the liquid supplied to the second common flow path 24 flows into the pressurizing chambers 10 lined up along the second common flow path 24, and some of the liquid is The liquid is discharged from the discharge hole 8, and some of the other liquid flows into the first common flow path 20 located on the opposite side of the second common flow path 24 with respect to the pressurizing chamber 10. It is discharged from the channel member 4 to the outside.

By arranging the second common flow path 24 on both sides of the first common flow path 20 and the first common flow path 20 on both sides of the second common flow path 24, for one pressurizing chamber row 11A. , one first common flow path 20 and one second common flow path 24 are connected, and for another pressurizing chamber row 11A, another first common flow path 20 and another second common flow path This is preferable because the number of first common flow paths 20 and second common flow paths 24 can be reduced to about half compared to the case where the first common flow paths 20 and second common flow paths 24 are connected. Since the number of the first common flow path 20 and the second common flow path 24 is small, the number of pressurizing chambers 10 can be increased to achieve high resolution, and the first common flow path 20 and the second common flow path 24 can be made thicker. This makes it possible to reduce the difference in ejection characteristics from the ejection holes 8 and to reduce the size of the head main body 2a in the planar direction.

The pressure applied to the first common flow path 20 side portion of the first individual flow path 12 connected to the first common flow path 20 is reduced by the pressure applied to the first individual flow path 20 in the first common flow path 20 due to the influence of pressure loss. It changes depending on the position of 12. The pressure applied to the portion on the second individual flow path 14 side that is connected to the second common flow path 24 changes depending on the position of the second individual flow path 14 within the second common flow path 24 due to the influence of pressure loss. If the opening 20a to the outside of the first common flow path 20 is arranged at one end in the first direction, and the opening 24a to the outside of the second common flow path 24 is arranged at the other end in the first direction. , the difference in pressure caused by the arrangement of each first individual flow path 12 and each second individual flow path 14 is canceled out, and the difference in pressure applied to each discharge hole 8 can be reduced. Note that both the opening 20a of the first common flow path 20 and the opening 24a of the second common flow path 24 open to the pressurizing chamber surface 4-1.

When the liquid is not being discharged, the discharge hole 8 retains a meniscus of liquid. Since the pressure of the liquid is negative in the discharge hole 8 (a state in which the liquid is trying to be drawn into the first flow path member 4), the meniscus can be maintained in balance with the surface tension of the liquid. If the positive pressure increases, the liquid will overflow, and if the negative pressure increases, the liquid will be drawn into the first channel member 4, making it impossible to maintain a state in which the liquid can be discharged. Therefore, when the liquid flows from the second common flow path 24 to the first common flow path 20, it is necessary to prevent the difference in pressure of the liquid at the discharge hole 8 from becoming too large.

The wall surface of the first common channel 20 on the side of the discharge hole surface 4-2 serves as a first damper 28A. One surface of the first damper 28A faces the first common flow path 20, and the other surface faces the damper chamber 29. The presence of the damper chamber 29 allows the first damper 28A to be deformed, and by deforming, the volume of the first common flow path 20 can be changed. When the liquid in the pressurizing chamber 10 is pressurized to discharge the liquid, a part of the pressure is transmitted to the first common channel 20 through the liquid. As a result, the liquid in the first common flow path 20 vibrates, and the vibration is transmitted to the original pressurizing chamber 10 and other pressurizing chambers 10, causing fluid crosstalk that changes the discharge characteristics of the liquid. Sometimes. When the first damper 28A exists, the vibration of the liquid transmitted to the first common flow path 20 causes the first damper 28A to vibrate and attenuate, making it difficult for the vibration of the liquid in the first common flow path 20 to be sustained. Therefore, the influence of fluid crosstalk can be reduced. The first damper 28A also serves to stabilize the supply and discharge of liquid.

The wall surface of the second common flow path 24 on the pressure chamber surface 4-1 side serves as a second damper 28B. One surface of the second damper 28B faces the second common flow path 24, and the other surface faces the damper chamber 29. Similarly to the first damper 28A, the second damper 28B can also reduce the influence of fluid crosstalk. The second damper 28B also serves to stabilize the supply and discharge of liquid.

The pressurizing chamber 10 is arranged facing the pressurizing chamber surface 4-1, and includes a pressurizing chamber main body 10a that receives pressure from the displacement element 50, and a discharge hole surface 4-1 from below the pressurizing chamber main body 10a. This is a hollow region including a descender 10b which is a partial flow path connected to the discharge hole 8 which is open to the discharge hole 8. The pressurizing chamber main body 10a has a right cylindrical shape and a circular planar shape. Since the planar shape is circular, the displacement amount when the displacement element 50 is deformed by the same force and the volume change of the pressurizing chamber 10 caused by the displacement can be increased. The descender 10b has a right cylindrical shape with a smaller diameter than the pressurizing chamber main body 10a, and has a circular cross-sectional shape. Further, the descender 10b is arranged at a position that fits within the pressurizing chamber main body 10a when viewed from the pressurizing chamber surface 4-1.

The plurality of pressurizing chambers 10 are arranged in a staggered manner on the pressurizing chamber surface 4-1. The plurality of pressurization chambers 10 constitute a plurality of pressurization chamber rows 11A along the first direction. In each pressurizing chamber row 11A, pressurizing chambers 10 are arranged at approximately equal intervals. The pressurizing chambers 10 belonging to the adjacent pressurizing chamber rows 11A are arranged to be shifted by half the interval in the first direction. In other words, a pressurizing chamber 10 belonging to a certain pressurizing chamber row 11A is in the first direction with respect to two consecutive pressurizing chambers 10 belonging to the pressurizing chamber row 11A located next to it. It is located almost in the center.

Thereby, the pressurizing chambers 10 belonging to every other pressurizing chamber row 11A are arranged along the second direction, forming a pressurizing chamber row 11B.

In this embodiment, there are 51 first common channels 20, 50 second common channels 24, and 100 pressurizing chamber rows 11A. (Here, the dummy pressurizing chamber row 11D, which is composed only of the dummy pressurizing chambers 10D described later, is not included in the number of the above-mentioned pressurizing chamber rows 11A.In addition, the dummy pressurizing chamber row 11D, which is described later, is not included in the number of the pressurizing chamber rows 11A. The second common flow path 24, which is only the pressurization chamber 10D, is not included in the number of second common flow paths 24 mentioned above.) Furthermore, each pressurization chamber row 11A includes 16 pressurization chambers 10. It is. As described above, since the pressurizing chambers 10 are arranged in a staggered manner, the number of pressurizing chamber rows 11B is 32.

The plurality of pressurizing chambers 10 are arranged in a lattice shape along the first direction and the second direction on the discharge hole surface 4-2. The plurality of ejection holes 8 constitute a plurality of ejection hole rows 9A along the first direction. The discharge hole row 9A and the pressurization chamber row 11A are arranged at substantially the same position.

The area center of gravity of the pressurizing chamber 10 and the discharge hole 8 connected to the pressurizing chamber 10 are shifted in the first direction. Within one pressurization chamber row 11A, the directions of displacement are the same, and in the adjacent pressurization chamber rows 11A, the directions of displacement are opposite. Thereby, the discharge holes 8 connected from the pressurizing chambers 10 belonging to the two pressurizing chamber rows 11B constitute one discharge hole row 9B arranged along the second direction.

Therefore, in this embodiment, there are 100 ejection hole columns 9A and 16 ejection hole rows 9B.

The area center of gravity of the pressurizing chamber main body 10a and the discharge hole 8 connected from the pressurizing chamber main body 10a are substantially shifted in position in the first direction. The descender 10b is arranged at a position shifted in the direction of the discharge hole 8 with respect to the pressurizing chamber main body 10a. The side wall of the pressurizing chamber main body 10a and the side wall of the descender 10b are arranged so as to be in contact with each other, thereby making it difficult for liquid to stagnate within the pressurizing chamber main body 10a.

The discharge hole 8 is arranged at the center of the descender 10b. Here, the central portion refers to a region within a circle half the diameter of the descender 10b, centered on the area gravity center of the descender 10b.

The connection portion between the first individual flow path 12 and the pressurizing chamber main body 10a is arranged on the opposite side of the descender 10b with respect to the area center of gravity of the pressurizing chamber main body 10a. Thereby, the liquid flowing from the descender 10b spreads over the entire pressurizing chamber main body 10a and then flows toward the first individual flow path 12, so that it is difficult for the liquid to stagnate within the pressurizing chamber main body 10a.

The second individual flow path 14 is drawn out in the plane direction from the surface of the descender 10b on the discharge hole surface 4-2 side and is connected to the second common flow path 24. The direction in which the descender 10b is pulled out is the same as the direction in which the descender 10b is shifted with respect to the pressurizing chamber main body 10a.

The angle formed by the first direction and the second direction (the longitudinal direction of the head main body 2a) is deviated from a right angle. For this reason, the discharge holes 8 belonging to the discharge hole row 9A arranged along the first direction are arranged offset in the second direction by the angle deviated from the right angle. Since the ejection hole rows 9A are arranged side by side in the second direction, the ejection holes 8 belonging to different ejection hole rows 9A are arranged with a corresponding shift in the second direction. In combination, the discharge holes 8 of the first flow path member 4 are arranged at regular intervals in the second direction, so that pixels formed by the discharged liquid fill a predetermined range. Can print.

If the ejection holes 8 belonging to one ejection hole row 9A are arranged completely in a straight line along the first direction, printing can be performed to fill a predetermined range as described above. However, in such an arrangement, the misalignment between the direction orthogonal to the second direction and the conveyance direction that occurs when the liquid ejection head 2 is installed in the printer 1 has a greater effect on printing accuracy. Therefore, it is preferable to replace the arrangement of the ejection holes 8 between the adjacent ejection hole rows 9A from the above-described arrangement of the ejection holes 8 in a straight line.

In this embodiment, the arrangement of the discharge holes 8 is as follows. In FIG. 3, when the discharge holes 8 are projected in a direction perpendicular to the second direction, 32 discharge holes 8 are projected within the range of the virtual straight line R, and each discharge hole 8 is lined up at an interval of 360 dpi within the virtual straight line R. . Thereby, if the printing paper P is conveyed in a direction perpendicular to the virtual straight line R and printed, printing can be performed at a resolution of 360 dpi. The discharge holes 8 projected within the virtual straight line R belong to all (16) discharge holes 8 belonging to one discharge hole row 9A and two discharge hole rows 9A located on both sides of the discharge hole row 9A. There are eight half discharge holes (eight pieces) each. In each discharge hole row 9B, the discharge holes 8 are arranged at intervals of 22.5 dpi (because 360/16=22.5).

The first common flow path 20 and the second common flow path 24 are straight in the range where the discharge holes 8 are lined up in a straight line, and are shifted in parallel between the discharge holes 8 where the straight lines are shifted. In the first common flow path 20 and the second common flow path 24, since there are few places where this deviation occurs, the flow path resistance is reduced. Moreover, since this parallel shifted portion is arranged at a position that does not overlap with the pressurizing chambers 10, it is possible to reduce variations in discharge characteristics for each pressurizing chamber 10.

One row (that is, two rows in total) of pressurizing chamber rows 11A at both ends in the second direction includes the normal pressurizing chamber 10 and the first dummy pressurizing chamber 10D (therefore, this The pressurizing chamber row 11A is sometimes referred to as a dummy pressurizing chamber row 11D). Moreover, one row (that is, two rows in total at both ends) of dummy pressurizing chamber row 11D in which only dummy pressurizing chambers 10D are lined up is arranged further outside the dummy pressurizing chamber row 11D. The flow channels, one at each end in the second direction (that is, two in total), have the same shape as the normal first common flow channel 24, but are not directly connected to the pressurizing chamber 10. It is not connected and is only connected to the dummy pressurizing chamber 10D.

The first flow path member 4 includes an end flow path 30 extending in the first direction at a position outside in the second direction of the common flow path group consisting of the first common flow path 20 and the second common flow path 24. have. The end flow path 30 is lined up with an opening 30c located further outside of the opening 20a of the first common flow path 20 that is lined up with the pressurization chamber side 4-1. The flow path connects the opening 24a of the second common flow path 24 with the opening 30d located further outside, and the flow path resistance of the end flow path 30 is the same as that of the first common flow path 20 and the second common flow path 30. It is smaller than the flow path resistance of the flow path 24. The end flow path 30 will be explained in detail later.

The second flow path member 6 is joined to the pressurizing chamber surface 4-1 of the first flow path member 4, and has a second integrated flow path 26 that supplies liquid to the second common flow path 24, and a first common flow path 26 that supplies liquid to the second common flow path 24. It has a first integrated flow path 22 for recovering the liquid in the flow path 20. The thickness of the second flow path member 6 is thicker than the first flow path member 4, and is about 5 to 30 mm.

The second flow path member 6 is joined to the pressure chamber surface 4-1 of the first flow path member 4 in a region to which the piezoelectric actuator substrate 40 is not connected. More specifically, they are joined so as to surround the piezoelectric actuator substrate 40. By doing so, it is possible to suppress a portion of the discharged liquid from adhering to the piezoelectric actuator substrate 40 in the form of mist. Furthermore, since the first flow path member 4 is fixed at the outer periphery, it is possible to suppress vibration of the first flow path member 4 due to the drive of the displacement element 50, and occurrence of resonance or the like.

Further, a through hole 6c vertically passes through the center of the second flow path member 6. A wiring member such as an FPC (Flexible Printed Circuit) that transmits a drive signal for driving the piezoelectric actuator board 40 is passed through the through hole 6c. Note that the through hole 6c on the side of the first flow path member 4 is a widened portion 6ca which is wider in the transverse direction, and the wiring members extending from the piezoelectric actuator substrate 40 to both sides in the transverse direction are widened. It is bent at the portion 6ca, goes upward, and passes through the through hole 6. In addition, since the convex part of the part which widens to widened part 6ca may damage a wiring member, it is preferable to make it R-shaped.

By arranging the first integrated flow path 22 in a second flow path member 6 that is separate from the first flow path member 4 and that is thicker than the first flow path member 4, the cross-sectional area of the first integrated flow path 22 can be increased. As a result, the difference in pressure loss due to the difference in the position where the first integrated flow path 22 and the first common flow path 20 are connected can be reduced. The flow path resistance of the first integrated flow path 22 (more precisely, the flow path resistance of the range connected to the first common flow path 20 in the first integrated flow path 22) is the flow path resistance of the first integrated flow path 20. It is preferable to make it 1/100 or less.

By arranging the second integrated flow path 26 in a second flow path member 6 that is separate from the first flow path member 4 and is thicker than the first flow path member 4, the cross-sectional area of the second integrated flow path 26 can be increased. As a result, the difference in pressure loss due to the difference in the position where the second integrated flow path 26 and the second common flow path 24 are connected can be reduced. The flow path resistance of the second integrated flow path 26 (more precisely, the flow path resistance of the range of the second integrated flow path 26 that is connected to the first integrated flow path 22) is the flow path resistance of the second integrated flow path 24. It is preferable to make it 1/100 or less.

The first integrated flow path 22 is arranged at one end of the second flow path member 6 in the width direction, and the second integrated flow path 26 is arranged at the other end of the second flow path member 6 in the width direction, The structure is such that each flow path faces the first flow path member 4 side and is connected to the first common flow path 20 and the second common flow path 24, respectively. By doing so, the cross-sectional area of the first integrated flow path 22 and the second integrated flow path 26 can be increased (that is, the flow path resistance can be reduced), and the second flow path member 6 can be connected to the first flow path member 26. It is possible to increase the rigidity by fixing the outer periphery of the wiring member, and to provide a through hole 6c through which the wiring member passes.

The second flow path member 6 is configured by laminating plates 6a and 6b of the second flow path member. On the upper surface of the plate 6b, there is a groove that becomes the first integrated flow path main body 22a, which is a part of the first integrated flow path 22 that extends in the second direction and has a low flow resistance, and a groove that becomes the first integrated flow path main body 22a, which is a part of the first integrated flow path 22 that extends in the second direction. A groove extending in the second direction and serving as the second integrated flow path body 26a, which is a portion with low flow path resistance, is arranged.

A plurality of first connecting channels 22b extend downward (in the direction of the first channel member 4) from the groove that becomes the first integrated channel body 22a, and open onto the pressurizing chamber surface 4-1. It is connected to the opening 20a of the first common flow path. The first connection channels 22b are separated by partitions 6ba (that is, the first connection channels 22b are branched on the first common channel 20 side). Thereby, the rigidity of the connection between the second flow path member 6 and the first flow path member 4 can be increased. Furthermore, in the second direction, the length of the partition 6ba is longer than the length of the first connection flow path 22b, thereby increasing the rigidity of the connection between the second flow path member 6 and the first flow path member 4. Can be made high.

A plurality of second connecting channels 26b extend downward (in the direction of the first channel member 4) from the groove that becomes the second integrated channel main body 26a, and open onto the pressurizing chamber surface 4-1. It is connected to the opening 24a of the second common flow path. Each of the second connection flow paths 26b is separated by a partition 6bb (that is, the second connection flow path 26b is branched on the second common flow path 24 side). Thereby, the rigidity of the connection between the second flow path member 6 and the first flow path member 4 can be increased. Furthermore, in the second direction, the length of the partition 6bb is longer than the length of the second connection flow path 26b, thereby increasing the rigidity of the connection between the second flow path member 6 and the first flow path member 4. Can be made high.

An opening 22c is provided in the plate 6a at one end of the first integrated channel 22 in the second direction. An opening 26c is provided in the plate 6a at the other end of the second integrated channel 26 in the second direction. Although the liquid is supplied from the opening 26c of the second integrated flow path 26 and recovered from the opening 22c of the first integrated flow path 22, the supply and recovery may be reversed.

A damper may be provided in the first integrated flow path 22 and the second integrated flow path 26 to stabilize the supply or discharge of the liquid against fluctuations in the amount of liquid discharged. Furthermore, filters may be provided in the first integrated flow path 22 and the second integrated flow path 26 to make it difficult for foreign objects and air bubbles to enter the first flow path member 4.

A piezoelectric actuator substrate 40 including displacement elements 50 is bonded to the pressure chamber surface 4-1, which is the upper surface of the first flow path member 4, so that each displacement element 50 is positioned above the pressure chamber 10. It is located. The piezoelectric actuator substrate 40 occupies an area having approximately the same shape as the pressurizing chamber group formed by the pressurizing chambers 10 . Further, the opening of each pressurizing chamber 10 is closed by joining the piezoelectric actuator substrate 40 to the pressurizing chamber surface 4-1 of the flow path member 4. The piezoelectric actuator substrate 40 has a rectangular shape that is elongated in the same direction as the head main body 2a. Furthermore, a signal transmission section such as an FPC for supplying signals to each displacement element 50 is connected to the piezoelectric actuator board 40. The second flow path member 6 has a through hole 6c extending vertically in the center thereof, and the signal transmission section is electrically connected to the control section 88 through the through hole 6c. The signal transmission section has a shape extending in the short direction from one long side end to the other long side end of the piezoelectric actuator board 40, and the wiring arranged in the signal transmission section extends along the short side direction. It is preferable to extend the wires and line them up in the longitudinal direction, as this makes it easier to maintain the distance between the wires.

Individual electrodes 44 are arranged at positions facing each pressurizing chamber 10 on the upper surface of the piezoelectric actuator substrate 40 .

The channel member 4 has a laminated structure in which a plurality of plates are laminated. Twelve plates from plate 4a to plate 4l are stacked in order from the pressure chamber surface 4-1 side of the flow path member 4. These plates have a large number of holes and grooves formed therein. The holes and grooves can be formed, for example, by etching each plate made of metal. The thickness of each plate is 10-300μ
By setting the diameter to about m, the accuracy of forming holes can be increased. The plates 4f to 4i have the same shape, and although they may be composed of one plate, in order to form the holes with high accuracy, they are composed of four plates. The plates are aligned and stacked such that the holes communicate with each other to form a flow path such as the first common flow path 20.

A pressurizing chamber main body 10a is open on the pressurizing chamber surface 4-1 of the flat flow path member 4, and a piezoelectric actuator substrate 40 is bonded to the pressurizing chamber main body 10a. Furthermore, an opening 24a for supplying liquid to the second common flow path 24 and an opening 20a for recovering liquid from the first common flow path 20 are opened in the pressurizing chamber surface 4-1. A discharge hole 8 is opened in a discharge hole surface 4-2 of the flow path member 4, which is a surface opposite to the pressure chamber surface 4-1. Note that a plate may be further laminated on the pressurizing chamber surface 4-1 to close the opening of the pressurizing chamber main body 10a, and the piezoelectric actuator substrate 40 may be bonded thereon. By doing so, it is possible to reduce the possibility that the ejected liquid comes into contact with the piezoelectric actuator substrate 40, and the reliability can be further improved.

The structure for discharging liquid includes a pressurizing chamber 10 and a discharge hole 8. The pressurizing chamber 10 includes a pressurizing chamber main body 10a facing the displacement element 50, and a descender 10b having a smaller cross-sectional area than the pressurizing chamber main body 10a. The pressurizing chamber main body 10a is formed in a plate 4a, and the descender 10b has holes formed in the plates 4b to 4k overlapped with each other, and further closed (other than the discharge holes 8) with a nozzle plate 4l. It is made.

A first individual flow path 12 is connected to the pressurization chamber main body 10a, and the first individual flow path 12 is connected to a first common flow path 20. The first individual flow path 12 includes a circular hole passing through the plate 4b, a through groove extending in the planar direction in the plate 4c, and a circular hole passing through the plate 4d. The first common flow path 20 is formed by overlapping holes formed in the plates 4f to 4i, and further closing the upper side with a plate 4e and the lower side with a plate 4j.

A second individual flow path 14 is connected to the descender 10b, and the second individual flow path 14 is connected to a second common flow path 24. The second individual flow path 14 is a through groove extending in the planar direction in the plate 4j. The second common flow path 24 is formed by overlapping holes formed in the plates 4f to 4i, and further closing the upper side with a plate 4e and the lower side with a plate 4j.

Regarding the flow of liquid, to summarize, the liquid supplied to the second integrated flow path 26 passes through the second common flow path 24 and the second individual flow path 14 in order and enters the pressurizing chamber 10, and some of the liquid is It is discharged from the discharge hole 8. The liquid that has not been ejected passes through the first individual flow path 12 and enters the first common flow path 20, then enters the first integrated flow path 22, and is discharged to the outside of the head body 2.

The piezoelectric actuator substrate 40 has a laminated structure consisting of two piezoelectric ceramic layers 40a and 40b that are piezoelectric bodies. These piezoelectric ceramic layers 40a and 40b each have a thickness of about 20 μm. That is, the thickness from the top surface of the piezoelectric ceramic layer 40a of the piezoelectric actuator substrate 40 to the bottom surface of the piezoelectric ceramic layer 40b is about 40 μm. The thickness ratio of the piezoelectric ceramic layer 40a and the piezoelectric ceramic layer 40b is 3:7 to 7:3, preferably 4:6 to 6:4. Both piezoelectric ceramic layers 40a and 40b extend across the plurality of pressurizing chambers 10. These piezoelectric ceramic layers 40a and 40b are made of, for example, lead zirconate titanate (PZT) based, NaNbO ₃ based, BaTiO ₃ based, (BiNa)NbO ₃ based, BiNaNb ₅ O ₁₅ based, etc., which have ferroelectric properties. Made of ceramic material.

The piezoelectric actuator substrate 40 has a common electrode 42 made of a metal material such as Ag--Pd, and individual electrodes 44 made of a metal material such as Au. The thickness of the common electrode 42 is about 2 μm, and the thickness of the individual electrodes 44 is about 1 μm.

The individual electrodes 44 are arranged at positions facing each pressurizing chamber 10 on the upper surface of the piezoelectric actuator substrate 40 . The individual electrodes 44 include an individual electrode body 44a whose planar shape is one size smaller than the pressurization chamber main body 10a and a substantially similar shape to the pressurization chamber main body 10a, and an extraction electrode drawn out from the individual electrode main body 44a. 44b. A connection electrode 46 is formed in a portion of one end of the extraction electrode 44b that is extracted outside the area facing the pressurizing chamber 10. The connection electrode 46 is made of conductive resin containing conductive particles such as silver particles, and is formed to have a thickness of about 5 to 200 μm. Furthermore, the connection electrode 46 is electrically connected to an electrode provided in the signal transmission section.

Further, a common electrode surface electrode (not shown) is formed on the upper surface of the piezoelectric actuator substrate 40. The common electrode surface electrode and the common electrode 42 are electrically connected through a through conductor (not shown) arranged in the piezoelectric ceramic layer 40a.

Although details will be described later, a drive signal is supplied from the control section 88 to the individual electrodes 44 through a signal transmission section. The drive signal is supplied at regular intervals in synchronization with the conveyance speed of the print medium P.

The common electrode 42 is formed over almost the entire surface in the area between the piezoelectric ceramic layer 40a and the piezoelectric ceramic layer 40b. That is, the common electrode 42 extends so as to cover all the pressurizing chambers 10 in the area facing the piezoelectric actuator substrate 40. The common electrode 42 is connected to a surface electrode for a common electrode formed on the piezoelectric ceramic layer 40a at a position avoiding the electrode group consisting of the individual electrodes 44 via a via hole formed through the piezoelectric ceramic layer 40a. is grounded and held at ground potential. The common electrode surface electrode, like the plurality of individual electrodes 44, is directly or indirectly connected to the control section 88.

The portion of the piezoelectric ceramic layer 40a sandwiched between the individual electrode 44 and the common electrode 42 is polarized in the thickness direction, and becomes a displacement element 50 with a unimorph structure that is displaced when a voltage is applied to the individual electrode 44. There is. More specifically, when an electric field is applied to the piezoelectric ceramic layer 40a in the polarization direction with the individual electrodes 44 at a different potential than the common electrode 42, the part to which this electric field is applied becomes an active part that is distorted due to the piezoelectric effect. Work as. In this configuration, when the individual electrode 44 is set to a predetermined positive or negative potential with respect to the common electrode 42 by the control unit 88 so that the electric field and polarization are in the same direction, the portion of the piezoelectric ceramic layer 40a sandwiched between the electrodes (active part) contracts in the plane direction. On the other hand, since the piezoelectric ceramic layer 40b, which is an inactive layer, is not affected by the electric field, it does not shrink spontaneously and tries to restrict the deformation of the active region. As a result, a difference in strain in the polarization direction occurs between the piezoelectric ceramic layer 40a and the piezoelectric ceramic layer 40b, and the piezoelectric ceramic layer 40b is deformed so as to be convex toward the pressurizing chamber 10 (unimorph deformation).

Next, the liquid ejection operation will be explained. The displacement element 50 is driven (displaced) by a drive signal supplied to the individual electrode 44 via a driver IC or the like under control from the control unit 88 . In this embodiment, liquid can be ejected using various drive signals, but here, a so-called pull drive method will be described.

The individual electrodes 44 are set to a higher potential (hereinafter referred to as high potential) than the common electrode 42 in advance, and each time there is a discharge request, the individual electrodes 44 are once set to the same potential as the common electrode 42 (hereinafter referred to as low potential), Thereafter, the potential is set to high again at a predetermined timing. As a result, the piezoelectric ceramic layers 40a and 40b return to their original (flat) shape at the timing when the individual electrode 44 becomes low potential, and the volume of the pressurizing chamber 10 returns to its initial state (the potentials of both electrodes are different). state). As a result, negative pressure is applied to the liquid within the pressurizing chamber 10. Then, the liquid in the pressurizing chamber 10 begins to vibrate at the natural vibration period. Specifically, first, the volume of the pressurizing chamber 10 begins to increase, and the negative pressure gradually decreases. Then, the volume of the pressurized chamber 10 becomes maximum and the pressure becomes almost zero. Then, the volume of the pressurizing chamber 10 begins to decrease, and the pressure increases. Thereafter, the individual electrodes 44 are brought to a high potential at a timing when the pressure is approximately at its maximum. Then, the first vibration applied and the next vibration overlap, and greater pressure is applied to the liquid. This pressure propagates inside the descender and causes the liquid to be discharged from the discharge hole 8.

That is, droplets can be ejected by supplying the individual electrodes 44 with a pulsed drive signal that keeps the potential low for a certain period of time with a high potential as a reference. If this pulse width is set to AL (Acoustic Length), which is half the natural vibration period of the liquid in the pressurizing chamber 10, in principle, the ejection speed and amount of the liquid can be maximized. The natural vibration period of the liquid in the pressurizing chamber 10 is largely influenced by the physical properties of the liquid and the shape of the pressurizing chamber 10, but is also influenced by the physical properties of the piezoelectric actuator substrate 40 and the flow path connected to the pressurizing chamber 10. It is also influenced by the characteristics of

In order to stabilize the liquid ejection characteristics, the head main body 2a is controlled to keep the temperature constant. Furthermore, since discharge and circulation of the liquid are more stable when the viscosity of the liquid is lower, the temperature is basically set to above room temperature. Therefore, it is basically heated, but if the environmental temperature is high, it may be cooled. In the following, a case of heating to an environmental temperature will be explained, but the same applies to a case of cooling.

In order to keep the temperature constant, the liquid ejection head 2 may be provided with a heater, or the temperature of the liquid to be supplied may be adjusted. In any case, if there is a difference between the environmental temperature and the target temperature, more heat will be radiated from the ends of the head body 2a in the longitudinal direction (second direction), so the head body 2a will be located at the center in the second direction. The temperature of the pressurizing chambers 10 located at the ends in the second direction and the ends in the fourth direction tends to be lower than the temperature of the liquid in the pressurizing chamber 10. If there is a difference in the temperature of the liquid in each pressurizing chamber 10 or the temperature of the displacement element 50, this causes a difference in the ejection characteristics of droplets, so that printing accuracy may be reduced.

Details of this embodiment will be explained using FIG. 6(a). The pressurizing chamber arrangement area 11C is an area where the pressurizing chamber 10 is arranged. More specifically, it is the region with the smallest area among the convex regions including all the pressurizing chambers 10 present in the head main body 2a. FIG. 6A shows a schematic parallelogram area.

The first integrated flow path 22 is arranged at least in the second direction in the range where the pressurizing chamber 10 exists (that is, the range of the pressurizing chamber arranging area 11C) than the pressurizing chamber arranging area 11C. The first extending portion 22g includes a first extending portion 22g. The first extending portion 22g extends in the second direction. The end of the first extending portion 22g in the second direction is connected to a first end portion 22h that is a part of the first integrated flow path 22. The first end portion 22h is arranged extending further in the second direction than the pressurizing chamber arrangement region 11C.

The second integrated flow path 26 is located in the pressurizing chamber arrangement area in at least the fourth direction (the opposite direction to the second direction) in the range where the pressurizing chamber 10 exists (i.e., the range of the pressurizing chamber arrangement area 11C). It includes a second extending portion 26g that is disposed in a third direction (a direction opposite to the first direction) from 11C. The second extending portion 26g extends in the fourth direction. The end of the second extending portion 26g in the fourth direction is connected to a second end portion 26h that is a part of the second integrated flow path 26. The second end portion 26h is arranged extending further in the fourth direction than the pressurizing chamber arrangement region 11C.

When the liquid circulates in the flow path, the first flow path member 4 and the second flow path member 6 around the flow path are directly heated. Further, the heat spreads from the heated portion to the surroundings by thermal conduction, and the entire head body 2a is warmed.

The end portions in the second direction and the end portions in the fourth direction of the head body 2a have a large surface area corresponding to the short side of the head body 2a when viewed from above, so heat can easily escape. The temperature tends to be lower than that in the center. Further, the end portions in the second direction and the end portions in the fourth direction of the head body 2a are often attached to a printer, and the temperature also decreases due to heat being transferred to the printer.

At the end of the head main body 2a in the second direction, a first end 22h extends into the second flow path member 6, and the second flow path member 6 and the first flow path member 4 are connected to each other at the first end. It is joined below 22h. Therefore, the heat of the liquid flowing to the first end 22h is transmitted from the second flow path member 6 to the first flow path member 4, so that the temperature of the first flow path member 4 can be equalized.

Further, in this embodiment, the second flow path member 6 below the first end portion 22h is solid without a gap for a damper or the like. Since thermal conductivity is thereby increased, the temperature of the first flow path member 4 can be made more uniform. Note that the solid here may include a small gap such as an adhesive escape groove, for example, a width of 1 mm or 500 μm or less and a depth of 500 μm or less. Further, if the first flow path member 4 below the first end portion 22h is solid, the temperature of the first flow path member 4 can be made more uniform.

Furthermore, if the lower surface of the first end 22h is made to be the upper surface (pressure chamber surface 4-1) of the first flow path member 4, the heat of the liquid flowing to the first end 22h can be transferred to the first end 22h. Since the heat is transmitted directly from the second flow path member 6 to the first flow path member 4, the temperature of the first flow path member 4 can be made more equal. In this case, the first end portion 22h is formed in a groove-like structure that opens on the lower side of the second flow path member 6, and by joining the first flow path member 4 to the second flow path member 6, The groove is closed by the first flow path member 4 and becomes a tubular first end portion 22h.

Further, the flow path of the first end portion 22h is directed downward (first flow path member 4) side, is once connected to the flow path provided in the first flow path member 4, and is then re-introduced into the second flow path member 6. After connecting to the flow path, it may be connected to the outside via the opening 22c.

At the end of the head main body 2a in the fourth direction, a second end 26h extends into the second flow path member 6, and the second flow path member 6 and the first flow path member 4 are connected to each other at the second end. It is joined below 26h. Therefore, the heat of the liquid flowing to the second end 26h is transmitted from the second flow path member 6 to the first flow path member 4, so that the temperature of the first flow path member 4 can be equalized.

Further, in this embodiment, the second flow path member 6 below the second end portion 26h is solid. This increases thermal conductivity, so the temperature of the first flow path member 4 can be made more uniform. Further, if the first flow path member 4 below the second end portion 26h is solid, the temperature of the first flow path member 4 can be made more uniform.

Furthermore, if the lower surface of the second end 26h is made to be the upper surface (pressure chamber surface 4-1) of the first flow path member 4, the heat of the liquid flowing to the second end 26h can be transferred to the second end 26h. Since the heat is transmitted directly from the second flow path member 6 to the first flow path member 4, the temperature of the first flow path member 4 can be made more equal.

Further, the flow path at the second end portion 26h is once connected to the flow path provided in the first flow path member 4, and then connected again to the flow path in the second flow path member 6, and then externally through the opening 26c. It may also be connected to

The structure of the second flow path member 6 and the first flow path member 4 in the vicinity of the first end 22h and the second end 26h is such that the structure of the second flow path member 6 and the first flow path member 4 in the vicinity of the first end 22h and the second end 26h is not limited to the lower part of the first end 22h and the second end 26h. Providing a solid portion in the short direction of the head main body 2a somewhere in the range where the first end 22h and the second end exist in the two directions helps to equalize the temperature. preferred against.

The first end portion 22h not only extends in the second direction beyond the pressurization chamber arrangement region 11C, but also extends in the third direction, so that the influence from the end portion of the head body 2a in the second direction can be made difficult to be transmitted to the pressurizing chamber arrangement region 11C. Here, extending in the third direction means extending not in the first direction but in the third direction, and more specifically, means that the angle with respect to the third direction is smaller than 90 degrees.

If the first end portion 22h extends in the third direction from the center of the pressurization chamber arrangement region 11C, the influence from the end of the head body 2a in the second direction is difficult to be transmitted to the pressure chamber arrangement region 11C. can. Extending in the third direction from the center of the pressurization chamber arrangement area 11C means that there is a portion of the pressurization chamber arrangement area 11C that is located in the third direction from the center in the direction perpendicular to the second direction. That is what it means. Specifically, as shown in FIG. 6(b), the first end 122h is located in the third direction from the virtual straight line L1 indicating the center of the pressurizing chamber arrangement region 11C in the direction orthogonal to the second direction. This indicates that there are some parts that are

Similarly, for the second end 26h, if the second end 26h extends in the first direction from the center of the pressurizing chamber arrangement region 11C, the influence from the end of the head main body 2a in the fourth direction can be reduced. , it is possible to make it difficult for the pressure to be transmitted to the pressurization chamber arrangement area 11C. In FIG. 6(b), there is a portion where the first end 126h is located in the first direction relative to the virtual straight line L1 indicating the center of the pressurizing chamber arrangement region 11C in the direction orthogonal to the second direction. It shows the form.

Further, as shown in FIG. 6(c), if the first end 222h extends in the third direction beyond the pressurizing chamber arrangement region 11C, the influence from the end of the head body 2a in the second direction can be reduced. , it can be made difficult to transmit by the pressurization chamber arrangement area 11C. Extending in the third direction beyond the pressurization chamber arrangement area 11C means that it is located in the third direction from the furthest imaginary straight line L2 in the direction perpendicular to the second direction in the pressurization chamber arrangement area 11C. It means that there are parts.

Similarly, as for the second end 26h, as shown in FIG. The influence from the end of the direction can be made less likely to be transmitted through the pressurizing chamber arrangement region 11C. Extending in the first direction beyond the pressurization chamber arrangement area 11C means that it is located in the first direction from the farthest imaginary straight line L3 in the direction orthogonal to the second direction in the pressurization chamber arrangement area 11C. It means that there are parts.

The second flow path member 6 has a rectangular shape, and the second direction is substantially parallel to the first two opposing sides of the rectangular shape. Here, "substantially parallel" means that the angle formed is 5 degrees or less. The first direction is inclined with respect to two second opposing sides of the rectangular shape that are different from the first two opposing sides. And the slope is toward the second direction. As a result, the pressurizing chamber 10 disposed at the end in the second direction is disposed in the fourth direction at the end in the third direction rather than at the end in the first direction (see FIG. 3). This portion corresponds to a portion where there is no flow path between the first integrated flow path 22 and the second integrated flow path 26 even if the first end portion 22h extends in the third direction. That is, the end of the head main body 2a in the second direction is a part that is more susceptible to the influence of temperature, and since that part is arranged recessed in the fourth direction, it can be made less susceptible to the influence of temperature. Since this arrangement relationship is the same at the end in the fourth direction, the end in the fourth direction can also be made less susceptible to the influence of temperature.

The first extending portion 22g extends in the second direction along the pressurizing chamber arrangement region 11C. It is preferable that the first extending portion 22g extends over at least the first direction side of the pressurizing chamber arrangement region 11C. Thereby, the temperature of the pressurizing chamber arrangement region 11C can be made more uniform. If the first extending portion 22g extends in the fourth direction beyond the side of the pressurizing chamber arrangement region 11C in the first direction, it is not affected by the temperature from the end of the head body 2a in the fourth direction. This is preferable because it makes it difficult to However, even if it extends in the fourth direction from the opening 20a of the first common flow path 20, that part is out of the liquid circulation path, so the liquid is not replaced much, and the contribution to temperature equalization is also comparatively low. The target is small. Furthermore, the stagnation of the liquid may also have an effect, such as making it easier for the pigment in the liquid to settle.

Therefore, the end flow path 30 is provided in the flow path member 4 on the fourth direction side from the pressurizing chamber arrangement region 11C. The opening 30c of the end flow path 30 is disposed closer to the fourth direction than the opening 20a of the first common flow path 20, and the opening 30c of the end flow path 30 is located closer to the fourth direction than the opening 20a of the first common flow path 20. The liquid flowing into the first extension portion 22g can be circulated through the end channel 30.

The same can be done for the second extending portion 26g. That is, the end flow path 30 is provided in the flow path member 4 on the second direction side from the pressurizing chamber arrangement region 11C. The opening 30d of the end flow path 30 is located closer to the second direction than the opening 24a of the second common flow path 24, and the opening 30d of the end flow path 30 is located closer to the second direction than the opening 24a of the second common flow path 24. The liquid flowing into the second extension 26g can be circulated through the end channel 30.

FIG. 7(a) is a schematic plan view of a head main body according to another embodiment of the present invention, and shows the same portion as FIG. 6(a). Here, consider the distance along the second direction in the region where the first end portion 322h and the pressurizing chamber arrangement region 11C overlap in the second direction.

The distance D13 [mm] along the second direction on the third direction side of the first end 322h is the distance D11 [mm] along the second direction on the first direction side of the first end 322h. It is shorter than . As a result, since the first end 322h is interrupted on the third direction side, the part that is easily affected by the temperature at the end of the head main body in the second direction is changed to the first end 322h, which is close to the other end. This makes it less susceptible to temperature effects.

The distance D21 [mm] along the second direction on the first direction side of the second end 326h is the distance D23 [mm] along the second direction on the third direction side of the second end 326h. It is shorter than . As a result, since the second end 326h is interrupted on the first direction side, the part that is easily affected by the temperature at the end of the head main body in the fourth direction is changed to the second end 326h, which is close to the other end. This makes it less susceptible to temperature effects.

FIG. 7(b) is a schematic plan view of a head main body according to another embodiment of the present invention, and shows the same portion as FIG. 6(a).

The distance D1 [mm] along the second direction between the first end 422h and the pressurizing chamber arrangement region 11C is the distance D1 [mm] along the second direction between the second end 426h and the pressurizing chamber arrangement region 11C. This distance is shorter than the distance D2 [mm]. The liquid is supplied from the outside to the second integrated flow path, passes through the first flow path member, passes through the first integrated flow path, and is recovered to the outside. Therefore, after passing through the second end 426h, the liquid whose temperature has decreased will pass through the first end 422h. Therefore, by arranging as described above, even if the temperature of the liquid passing through the first end portion 422h becomes slightly lower, the difference can be made less likely to affect the pressurizing chamber arrangement region 11C.

The distance D1 [mm] along the second direction between the first end 422h and the pressurizing chamber arrangement region 11C is the distance D1 [mm] along the second direction between the first end 422h and the pressurizing chamber arrangement region 11C. This is the average distance. More specifically, the distance D1 [mm] is a distance along the second direction in a region where the first end portion 422h and the pressurizing chamber arrangement region 11C overlap in the second direction. In FIG. 7B, the distance D1 [mm] is the distance D13 [mm] along the second direction on the third direction side of the first end 422h, and the distance D13 [mm] on the first direction side of the first end 422h. is the arithmetic mean of the distance D11 [mm] along the second direction.

The distance D2 [mm] along the second direction between the second end portion 426h and the pressurization chamber arrangement region 11C is the distance D2 [mm] along the second direction between the second end portion 426h and the pressurization chamber arrangement region 11C. This is the average distance. In FIG. 7(b), the distance D2 [mm] is the distance D21 [mm] along the second direction on the first direction side of the second end 426h, and the distance D21 [mm] on the third direction side of the second end 426h. is the arithmetic mean of the distance D23 [mm] along the second direction.

FIG. 7(c) is a schematic plan view of a head main body according to another embodiment of the present invention, and shows the same portion as FIG. 6(a).

The first end portion 522h has a smaller cross-sectional area on the downstream side, which is the opening to the outside, than on the first extension portion side, which is the upstream side. Further, the second end portion 526h has a smaller cross-sectional area on the downstream side of the second extension portion than on the upstream side that opens to the outside. Therefore, the average cross-sectional area of the first end 522h is smaller than the average cross-sectional area of the second end 526h. Since the liquid has a lower thermal conductivity than the second flow path member 6, the thick portion can reduce the loss of heat to the outside due to thermal conduction. Thereby, it is possible to suppress the temperature drop on the downstream side where the temperature drop is large.

In the head main body 2a, end channels 30 are provided in the first channel member 4 on the outside in the second direction and the outside in the fourth direction of the pressurizing chamber arrangement region 11C. The end flow path 30 has lower flow path resistance than the common flow path (the first common flow path 20 and the second common flow path). Since the flow resistance of the end flow path 30 is low, the flow rate per hour of the liquid flowing into the end flow path 30 is greater than the flow rate per time of the liquid flowing through the common flow path. Therefore, even if the heat dissipation from the end of the head main body 2a in the second direction is large, the temperature is difficult to be transmitted across the end flow path 30, so the temperature difference in the pressurizing chamber arrangement region 11C can be reduced. It is preferable that the flow path resistance of the common flow path is twice or more, particularly three times or more, the flow path resistance of the end flow path 30.

Moreover, not only can temperature drop be suppressed due to the liquid flowing through the end flow path 30 in the first flow path member 4, but also the presence of the end flow path 30 prevents the liquid from stagnation. The portion 22g can be arranged to extend in the fourth direction, and the second extending portion 26g can be arranged to extend in the second direction so that liquid retention is less likely to occur.

Note that the flow path resistance of the common flow path is the flow path resistance from the opening 24b of one second common flow path 24 to the opening 20a of one first common flow path 20. In this embodiment, the liquid supplied to one second common channel 24 flows into the pressurizing chambers of the two rows of pressurizing chambers 11A, and further flows into the two first common channels 20. Conversely, liquid from the two second common channels 24 flows into one first common channel 20 . From this relationship, the flow path resistance of the common flow path is such that the liquid supplied to one second common flow path 24 flows into the pressurization chambers of the two rows of pressurization chamber rows 11A, and then flows through the first common flow path. The flow path resistance is the same as that when flowing into a flow path resistance twice as high as 20. That is, the channel resistance of the common channel is the channel resistance of the second common channel 24 + (channel resistance of the individual channel / 16 + channel resistance of the first common channel 24 x 2) / 2, The channel resistance of the first common channel 20 + the channel resistance of the second common channel 24 + the channel resistance of the individual channels/32, and the channel resistance of the first common channel 20 + the second common channel 24 + the flow path resistance of the two pressurizing chamber rows 11A.

In this embodiment, the end channels 30 are provided on both sides of the pressurizing chamber arrangement region 11C, and although it is better to provide them on both sides in order to stabilize the temperature, even if only on one side, On one side of it the temperature can be stabilized.

When fixing the head body 2a and the printer 1 at the ends of the head body 2a in the second direction, heat conduction from both ends of the head body 2a to the printer 1 increases. The need to provide the end flow path 30 increases.

The end flow path 30 is provided with a wide portion 30a in which the width of the flow path is wider than the width of the common flow path, and a third damper 28c is provided on the pressurizing chamber side 4-1 of the wide portion 30a. It is being The third damper 28C has one surface facing the wide portion 30a and the other surface facing the damper chamber 29, making it deformable. The damping ability of a damper is largely influenced by the part of the deformable region where the width is the narrowest. Since the size of the head main body 2a that increases the width of the common flow path becomes large, the width of the common flow path cannot be made very large, and the first damper 28A and the second damper 28B provided in the common flow path alone are insufficient. , the damping capacity may not be sufficient. By increasing the width of the wide portion 30a, the damping ability of the third damper 28C can be increased. The width of the wide portion 30a is preferably twice or more, particularly three times or more, the width of the common flow path.

A damper may also be provided on the discharge hole surface 4-2 side of the wide portion 30a to further increase the damping ability.

Further, in the above embodiments, the first common flow path 20 is not directly connected to the second integrated flow path 26, and the second common flow path 24 is not directly connected to the first integrated flow path 22, but the main The invention is not limited to this form. That is, the common flow path may directly connect the first integrated flow path 22 and the second integrated flow path 26.

Furthermore, in the embodiments described above, the liquid circulates throughout the printer 1 by allowing the liquid to pass through the inside of the head body 2a, but the first integrated flow path 22 and the second integrated flow path It is also possible to supply liquid from both 26 and 26 and use it without circulation.

Further, the first integrated channel 22 and the second integrated channel 26 may be arranged in the first channel member 4 instead of in the second channel member 6. In this way, the first integrated flow path 22, the second integrated flow path 26, the first common flow path 20, and the second common flow path 24 are arranged in the same plane within the first flow path member 4. This allows the temperature in the plane direction to be more averaged. However, if you try to flow the liquid for printing and the liquid for suppressing retention and making temperature control possible through the first integrated flow path 22 and the second integrated flow path 26, the first flow path member 4 Either increase the thickness of the cross section of the first integrated flow path 22 and the second integrated flow path 26, or increase the size of the width direction of the head main body 2a to increase the height of the first integrated flow path 22 and the second integrated flow path 26. It is necessary to increase the cross-sectional widths of the flow path 22 and the second integrated flow path 26. In the former case, the AL becomes longer, which may make it difficult to increase the drive frequency, and in the latter case, the head body 2a becomes larger, so the spacing when using a plurality of head bodies 2a becomes wider. Printing accuracy may decrease. Therefore, the first integrated flow path 22 and the second integrated flow path 26 are preferably arranged in the second flow path member 6.

1... Printer 2... Liquid ejection head 2a... Head main body 4... First channel member 4a to 4l... Plate (of the first channel member) 4-1... Pressure Chamber surface 4-2... Discharge hole surface 6... Second flow path member 6a, 6b... (Second flow path member) plate 6ba, 6bb... Partition 6c... (Second flow path member) Passage member) through hole 6ca...widened portion of through hole 8...discharge hole 9A...discharge hole row 9B...discharge hole row 10...pressure chamber 10a...pressure chamber main body 10b...Partial flow path (descender)
10D... Dummy pressurizing chamber 11A... Pressurizing chamber row 11B... Pressurizing chamber row 11C... Pressurizing chamber arrangement area 12... First individual flow path 14... Second individual flow Path 20...first common flow path (common flow path)
20a... (first common flow path) opening 22... first integrated flow path 22a... first integrated flow path main body 22b... first connection flow path 22c... (first integrated flow path) opening 22g...first extension part 22h...first end 24...second common flow path (common flow path)
24a...(Second common flow path) opening 26...Second integrated flow path 26a...Second integrated flow path main body 26b...Second connection flow path 26c...(Second integrated flow path) ) opening 26g...second extension part 26h...second end part 28A...first damper 28B...second damper 28C...third damper 29...damper chamber 30. ... End flow path 30a... Wide portion 30b... Narrow portion 30c, 30d... Opening (of end flow path) 40... Piezoelectric actuator substrate 40a... Piezoelectric ceramic layer 40b... Piezoelectric ceramic layer (diaphragm)
42...Common electrode 44...Individual electrode 44a...Individual electrode body 44b...Leader electrode 46...Connection electrode 50...Displacement element (pressure part)
60... Signal transmission unit 70... (Head mounted) frame 72... Head group 80A... Paper feed roller 80B... Collection roller 82A... Guide roller 82B... Conveyance roller 88...・Control unit P...Printing paper

Claims (14)

multiple discharge holes;
a plurality of pressurized chambers each connected to the plurality of discharge holes;
a plurality of pressurizing parts that respectively pressurize the plurality of pressurizing chambers;
a first integrated flow path that collects liquid from the plurality of pressurized chambers;
a second integrated flow path that supplies liquid to the plurality of pressurized chambers;
an end flow path connecting the first integrated flow path and the second integrated flow path;
Equipped with
The end flow path is provided in the first flow path member,
The first integrated flow path and the second integrated flow path are provided in a second flow path member different from the first flow path member,
The pressurization chamber includes a pressurization chamber main body and a descender connected from the pressurization chamber main body to the discharge hole,
A side wall of the pressurizing chamber main body and a side wall of the descender are arranged so as to be in contact with each other.
Liquid ejection head. A plurality of discharge holes, a plurality of pressurized chambers each connected to the plurality of discharge holes, a first common channel for recovering liquid from the plurality of pressurized chambers, and a supply of liquid to the plurality of pressurized chambers. a first flow path member having a second common flow path;
a second flow path member having a first integrated flow path that collects liquid from the first common flow path, and a second integrated flow path that supplies liquid to the second common flow path;
a plurality of pressurizing parts that respectively pressurize the plurality of pressurizing chambers;
Equipped with
The first channel member is composed of a plurality of plates and is located below the second channel member,
The plate located at the uppermost side of the plurality of plates in which the pressurizing chamber is provided is higher than the plate located at the lowermost side among the plurality of plates in which the first common flow path is provided. is also located on the upper side,
The pressurization chamber includes a pressurization chamber main body and a descender connected from the pressurization chamber main body to the discharge hole,
A side wall of the pressurizing chamber main body and a side wall of the descender are arranged so as to be in contact with each other.
Liquid ejection head. multiple discharge holes;
a plurality of pressurized chambers each connected to the plurality of discharge holes;
a plurality of pressurizing parts that respectively pressurize the plurality of pressurizing chambers;
a first integrated flow path that collects liquid from the plurality of pressurized chambers;
a second integrated flow path that supplies liquid to the plurality of pressurized chambers;
an end flow path connecting the first integrated flow path and the second integrated flow path;
Equipped with
The end flow path is provided in the first flow path member,
The first integrated flow path and the second integrated flow path are provided in a second flow path member different from the first flow path member,
When viewed from above,
The plurality of pressurizing chambers are arranged in a pressurizing chamber arrangement area,
The first integrated flow path is arranged in a first direction relative to the pressurization chamber arrangement region,
The second integrated flow path is arranged in a third direction opposite to the first direction, with respect to the pressurization chamber arrangement region,
The first integrated flow path extends in a second direction that intersects with the first direction, and includes a first end that is located further in the second direction than the pressurization chamber arrangement area. Ori,
The second integrated flow path extends in a fourth direction opposite to the second direction beyond the pressurization chamber arrangement area, and is arranged in the fourth direction beyond the pressurization chamber arrangement area. a second end that is
Below the first end, the first flow path member and the second flow path member are joined, or the upper surface of the first flow path member is the lower surface of the first end. Either
Below the second end, the first flow path member and the second flow path member are joined, or the upper surface of the first flow path member is the lower surface of the second end. A liquid ejection head that is either A plurality of discharge holes, a plurality of pressurized chambers each connected to the plurality of discharge holes, a first common channel for recovering liquid from the plurality of pressurized chambers, and a supply of liquid to the plurality of pressurized chambers. a first flow path member having a second common flow path;
a second flow path member having a first integrated flow path that collects liquid from the first common flow path, and a second integrated flow path that supplies liquid to the second common flow path;
a plurality of pressurizing parts that respectively pressurize the plurality of pressurizing chambers;
Equipped with
The first channel member is composed of a plurality of plates and is located below the second channel member,
The plate located at the uppermost side of the plurality of plates in which the pressurizing chamber is provided is higher than the plate located at the lowermost side among the plurality of plates in which the first common flow path is provided. is also located on the upper side,
When viewed from above,
The plurality of pressurizing chambers are arranged in a pressurizing chamber arrangement area,
The first integrated flow path is arranged in a first direction relative to the pressurization chamber arrangement region,
The second integrated flow path is arranged in a third direction opposite to the first direction, with respect to the pressurization chamber arrangement region,
The first integrated flow path extends in a second direction that intersects with the first direction, and includes a first end that is located further in the second direction than the pressurization chamber arrangement area. Ori,
The second integrated flow path extends in a fourth direction opposite to the second direction beyond the pressurization chamber arrangement area, and is arranged in the fourth direction beyond the pressurization chamber arrangement area. a second end that is
The first flow path member and the second flow path member are joined below the first end.
or, the upper surface of the first flow path member is a lower surface of the first end,
Below the second end, the first flow path member and the second flow path member are joined, or the upper surface of the first flow path member is the lower surface of the second end. A liquid ejection head that is either A plurality of discharge holes, a plurality of pressurized chambers each connected to the plurality of discharge holes, a first common channel for recovering liquid from the plurality of pressurized chambers, and a supply of liquid to the plurality of pressurized chambers. a first flow path member having a second common flow path;
a second flow path member having a first integrated flow path that collects liquid from the first common flow path, and a second integrated flow path that supplies liquid to the second common flow path;
a plurality of pressurizing parts that respectively pressurize the plurality of pressurizing chambers;
Equipped with
The first channel member is composed of a plurality of plates and is located below the second channel member,
The plate located at the uppermost side of the plurality of plates in which the pressurizing chamber is provided is higher than the plate located at the lowermost side among the plurality of plates in which the first common flow path is provided. is also located on the upper side,
The second flow path member is thicker than the first flow path member.
Liquid ejection head. A plurality of discharge holes, a plurality of pressurized chambers each connected to the plurality of discharge holes, a first common channel for recovering liquid from the plurality of pressurized chambers, and a supply of liquid to the plurality of pressurized chambers. a first flow path member having a second common flow path;
a second flow path member having a first integrated flow path that collects liquid from the first common flow path, and a second integrated flow path that supplies liquid to the second common flow path;
a plurality of pressurizing parts that respectively pressurize the plurality of pressurizing chambers;
Equipped with
The first channel member is composed of a plurality of plates and is located below the second channel member,
The plate located at the uppermost side of the plurality of plates in which the pressurizing chamber is provided is higher than the plate located at the lowermost side among the plurality of plates in which the first common flow path is provided. is also located on the upper side,
When viewed from above,
The plurality of pressurizing chambers are arranged in a pressurizing chamber arrangement area,
The first integrated flow path is arranged in a first direction relative to the pressurization chamber arrangement region,
The second integrated flow path is arranged in a third direction opposite to the first direction, with respect to the pressurization chamber arrangement region,
The second flow path member is a liquid ejection head having a through hole between the first integrated flow path and the second integrated flow path in the first direction. The plate located at the uppermost side of the plurality of plates in which the pressurizing chamber is provided is higher than the plate located at the lowermost side among the plurality of plates in which the second common flow path is provided. is also located at the top
The liquid ejection head according to any one of claims 2 and 4 to 6 . The pressurization chamber includes a pressurization chamber main body and a descender connected from the pressurization chamber main body to the discharge hole,
A side wall of the pressurizing chamber main body and a side wall of the descender are arranged so as to be in contact with each other.
The liquid ejection head according to any one of claims 3 to 6 . The second flow path member is thicker than the first flow path member.
The liquid ejection head according to any one of claims 1 to 4 and 6 . When viewed from above,
The plurality of pressurizing chambers are arranged in a pressurizing chamber arrangement area,
The first integrated flow path is arranged in a first direction relative to the pressurization chamber arrangement region,
The second integrated flow path is arranged in a third direction opposite to the first direction, with respect to the pressurization chamber arrangement region.
The liquid ejection head according to any one of claims 1, 2 and 5 . The first integrated flow path extends in a second direction that intersects with the first direction, and includes a first end that is located further in the second direction than the pressurization chamber arrangement area. Ori,
The second integrated flow path extends in a fourth direction opposite to the second direction beyond the pressurization chamber arrangement area, and is arranged in the fourth direction beyond the pressurization chamber arrangement area. a second end that is
Below the first end, the first flow path member and the second flow path member are joined, or the upper surface of the first flow path member is the lower surface of the first end. Either
Below the second end, the first flow path member and the second flow path member are joined, or the upper surface of the first flow path member is the lower surface of the second end. either
The liquid ejection head according to claim 6 or 10 . The liquid ejection head according to any one of claims 3, 4 and 11 , wherein the second flow path member located below the first end and the second end is solid. When viewed from above,
The second flow path member has a through hole between the first integrated flow path and the second integrated flow path in the first direction. The liquid ejection head described. A recording apparatus comprising: the liquid ejection head according to any one of claims 1 to 13; a transport section that transports a recording medium to the liquid ejection head; and a control section that controls the liquid ejection head.

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