JP6951386B2 - Liquid discharge head and recording device using it - Google Patents

Description

The present invention relates to a liquid discharge head and a recording device using the same.

Conventionally, as a printing head, for example, a liquid ejection head that performs various types of printing by ejecting a liquid onto a recording medium is known. The liquid discharge head includes, for example, a discharge hole for discharging the liquid, a pressurizing chamber for pressurizing the liquid so that the liquid is discharged from the discharge hole, and a first common flow path for supplying the liquid to the pressurizing chamber. Those provided with a second common flow path for recovering a liquid from a pressure chamber are known. The liquid flows from the first common flow path to the second common flow path through the pressurizing chamber even when the discharge is not performed so that the flow path is less likely to be clogged due to the retention of the liquid. It is known that the liquid is circulated including the outside. Further, in such a liquid discharge head, the plurality of first common flow paths and the plurality of second common flow paths are formed to extend in the lateral direction of the liquid discharge head, and alternately in the longitudinal direction of the liquid discharge head. It is known to arrange (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2009-143168

In the liquid discharge 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 end in the longitudinal direction of the liquid discharge head is the liquid discharge head. Compared to the pressurizing chamber located in the central part in the longitudinal direction of the above, it is more susceptible to the temperature of the external environment. Since the characteristics of the liquid (for example, viscosity) basically have temperature characteristics, if there is a temperature difference between the liquids in the pressurizing chamber, the discharge characteristics of the liquid discharged from the pressurizing chamber (discharge amount and discharge speed). There is a problem that the recording accuracy is deteriorated due to the difference in the recording accuracy.

Therefore, an object of the present invention is to provide a liquid discharge head capable of reducing the temperature difference in the liquid discharge head, and a recording device using the liquid discharge head.

The liquid discharge head of the present invention has a first flow path member having a plurality of discharge holes and a plurality of pressure chambers connected to the plurality of discharge holes, and a first flow path member for collecting liquid from the plurality of pressure chambers. A second flow path member laminated on the first flow path member having one integrated flow path and a second integrated flow path for supplying liquid to the plurality of pressurizing chambers, and the plurality of pressurizing chambers. A liquid discharge head including a plurality of pressurizing portions for pressurizing each of the above, and when viewed in a plan view, the plurality of pressurizing chambers are arranged in a pressurizing chamber arrangement region, and the first integrated flow The road is arranged in the first direction from the pressure chamber arrangement region, extends in the second direction intersecting with the first direction, and is the second from the pressure chamber arrangement region. The second integrated flow path includes the first end flow path arranged in the direction, and the second integrated flow path is arranged in the third direction opposite to the first direction from the pressure chamber arrangement area. In addition, the second end flow path that extends in the fourth direction, which is the opposite direction to the two directions, and is arranged in the fourth direction from the pressurizing chamber arrangement region, is included. Whether the first flow path member and the second flow path member are joined below the one end, or whether the upper surface of the first flow path member is the lower surface of the first end. The first flow path member and the second flow path member are joined below the second end portion, or the upper surface of the first flow path member is the second end portion. It is characterized in that it is either the lower surface.

Further, the liquid discharge head of the present invention includes a plurality of discharge holes, a plurality of pressure chambers connected to the plurality of discharge holes, a first integrated flow path for collecting liquid from the plurality of pressure chambers, and the plurality of pressure chambers. A liquid discharge head including a flow path member having a second integrated flow path for supplying a liquid to the pressurizing chamber and a plurality of pressurizing portions for pressurizing the plurality of pressurizing chambers, respectively, in a plan view. When this is done, the plurality of pressurizing chambers are arranged in the pressurizing chamber arrangement region, and the first integrated flow path is arranged in the first direction with respect to the pressurizing chamber arrangement region in the plane. At the same time, the first end flow path extending in the second direction intersecting the first direction and being arranged in the second direction from the pressurizing chamber arrangement region is included. The two integrated flow paths are arranged in the third direction opposite to the first direction and extend in the fourth direction opposite to the two directions from the pressurizing chamber arrangement region. Moreover, it is characterized by including a second end flow path arranged in the fourth direction with respect to the pressurizing chamber arrangement region.

Further, the recording device of the present invention is characterized by including the liquid discharge head, a transport unit for transporting the recording medium to the liquid discharge head, and a control unit for controlling the liquid discharge head.

According to the liquid discharge head of the present invention, the temperature difference in the liquid discharge head can be reduced.

(A) is a side view of a recording device including a liquid discharge head according to an embodiment of the present invention, and (b) is a plan view. (A) is a plan view of a head body which is a main part of the liquid discharge head of FIG. 1, and (b) is a plan view of (a) excluding the second flow path member. 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 cross-sectional view taken along the line VV of FIG. 4, and (b) is a partial vertical cross-sectional view of the head body of FIG. 2 (a). (A) is a schematic plan view of FIG. 2 (a), and (b) and (c) are schematic plan views of a liquid discharge head according to another embodiment of the present invention. (A) to (c) are schematic plan views of the liquid discharge head of another embodiment of the present invention.

FIG. 1A is a schematic side view of a (color inkjet) printer 1 which is a recording device including a liquid discharge head 2 according to an embodiment of the present invention, and FIG. 1B is a schematic plan view. Is. The printer 1 conveys the printing paper P, which is a recording medium, from the conveying roller 80A to the conveying roller 80B, so that the printing paper P is moved relative to the liquid ejection head 2. The control unit 88 controls the liquid ejection head 2 based on the image and character data to eject the liquid toward the recording medium P, land the droplets on the printing paper P, and print on the printing paper P. And so on.

In the present embodiment, the liquid discharge head 2 is fixed to the printer 1, and the printer 1 is a so-called line printer. Other embodiments of the recording apparatus of the present invention include an operation of moving the liquid discharge head 2 in a direction intersecting the transport direction of the printing paper P, for example, reciprocating in a direction substantially orthogonal to each other, and a printing paper P. A so-called serial printer, which alternately carries out the transfer of paper, can be mentioned.

A flat plate-shaped (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 discharge heads 2 are mounted on the respective holes, and the portion of the liquid discharge head 2 for discharging the liquid is 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 discharge heads 2 constitute one head group 72, and the printer 1 has four head groups 72.

The liquid discharge head 2 has an elongated long shape 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 arranged along a direction intersecting the conveying direction of the printing paper P, for example, a direction substantially orthogonal to each other, and the other two liquid ejection heads 2 are conveyed. One is lined up between the three liquid discharge heads 2 at positions displaced along the direction. The liquid discharge heads 2 are arranged so that the printable range of each liquid discharge head 2 is connected in the width direction of the printing paper P (in the direction intersecting the transport direction of the printing paper P) or the edges overlap. Therefore, printing without gaps in the width direction of the printing paper P is possible.

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

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

Further, in addition to printing the colored ink, a liquid such as a coating agent may be printed in order to perform a surface treatment on the printing paper P.

The printer 1 prints on the printing paper P which is a recording medium. The printing paper P is in a state of being wound around the paper feed roller 80A, passes between the two guide rollers 82A, passes under the liquid discharge head 2 mounted on the frame 70, and then passes through the lower side of the liquid discharge head 2. It passes between the two transport rollers 82B and is finally collected by the collection roller 80B. When printing, the printing paper P is conveyed at a constant speed by rotating the transfer roller 82B, and is printed by the liquid discharge head 2. The collection roller 80B winds up the printing paper P sent out from the transport roller 82B. The transport 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.

The recording medium may be a cloth or the like in addition to the printing paper P. Further, the printer 1 is in a form of transporting a transport belt instead of the printing paper P, and the recording medium is not only a roll-shaped one, but also a sheet of paper, a cut cloth, wood, etc. placed on the transport belt. It may be a tile or the like. Further, the wiring pattern of the electronic device or the like may be printed by discharging the liquid containing the conductive particles from the liquid discharge head 2. Further, a chemical agent may be produced by discharging a predetermined amount of liquid chemical agent or a liquid containing the chemical agent toward the reaction vessel or the like from the liquid discharge head 2 and reacting the mixture.

Further, a position sensor, a speed sensor, a temperature sensor and the like 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 which can be understood from the information from each sensor. In particular, if the discharge characteristics (discharge amount, discharge speed, etc.) of the liquid discharged from the liquid discharge head 2 are affected by the outside, the temperature of the liquid discharge head 2, the temperature of the liquid in the liquid tank, and the temperature of the liquid tank The drive signal for discharging the liquid in the liquid discharge head 2 may be changed according to the pressure applied to the liquid discharge head 2.

Next, the liquid discharge head 2 according to the embodiment of the present invention will be described. FIG. 2A is a plan view showing a head body 2a, which is a main part of the liquid discharge head 2 shown in FIG. FIG. 2B is a plan view of the head body 2a excluding the second flow path member 6. 3 and 4 are enlarged plan views of FIG. 2 (b). FIG. 5A is a vertical cross-sectional view taken along the line VV of FIG. FIG. 5B 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. 6A is a schematic plan view of the head main body 2a shown in FIG. 2A.

Each figure is drawn as follows for the sake of clarity. In FIGS. 2 to 4, the flow paths and the like below other objects that should be drawn with broken lines are drawn with solid lines. In FIG. 2A, the flow path in the first flow path member 4 is almost omitted, and only the arrangement of the pressurizing chamber 10 is shown.

In addition to the head body 2a, the liquid discharge head 2 may include a metal housing, a driver IC, a wiring board, and the like. Further, the head body 2a is a piezoelectric actuator in which a first flow path member 4, a second flow path member 6 that supplies a liquid to the first flow path member 4, and a displacement element 50 that is a pressurizing portion are incorporated. The substrate 40 and the like are included. The head body 2a has a flat plate shape that is long in one direction, and that direction may be 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 both ends of the second flow path member 6 in the longitudinal direction.

The first flow path member 4 constituting the head main body 2a has a flat plate shape, and the thickness thereof is about 0.5 to 2 mm. A large number of pressure chambers 10 are arranged side by side in the plane direction on the pressure chamber surface 4-1 which is the first main surface of the first flow path member 4. A large number of discharge holes 8 for discharging liquid 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. Each of the discharge holes 8 is connected to the pressurizing chamber 10. Hereinafter, the pressurizing chamber surface 4-1 will be described as being located above the discharge hole surface 4-2.

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

Pressurizing chambers 10 are lined up along both sides of the first common flow path 20, forming a total of two rows of pressurizing chambers 11A, one row 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.

Pressurizing chambers 10 are lined up along both sides of the second common flow path 24, forming a total of two rows of pressurizing chambers 11A, one row on each side. The first integrated flow path 22 and the pressurizing chambers 10 arranged on both sides thereof are connected via a second individual flow path 14. In the following, the first common flow path 20 and the second common flow path 24 may be collectively referred to as a common flow path.

In other words, the pressurizing chambers 10 are arranged side by side on the virtual line, the first common flow path 20 extends along one side of the virtual line, and along the other side of the virtual line. The second common flow path 24 extends. In the present embodiment, the virtual line in which the pressurizing chambers 10 are lined up is a straight line, but it may 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 arranged along the second common flow path 24, and a part thereof. Liquid is discharged from the discharge hole 8, and some of the other liquids flow 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, and the first It is discharged to the outside from the flow path member 4.

The second common flow path 24 is arranged on both sides of the first common flow path 20, and the first common flow path 20 is arranged on both sides of the second common flow path 24. One first common flow path 20 and one second common flow path 24 are connected to another first common flow path 20 and another second common flow path with respect to another pressurizing chamber row 11A. Compared with the case where 24 are connected, the number of the first common flow path 20 and the second common flow path 24 can be reduced to about half, which is preferable. Since the number of the first common flow path 20 and the second common flow path 24 can be reduced, the number of pressurizing chambers 10 can be increased to increase the resolution, or the first common flow path 20 and the second common flow path 24 can be made thicker. Therefore, the difference in discharge characteristics from the discharge hole 8 can be reduced, and the size of the head body 2a in the plane direction can be reduced.

The pressure applied to the portion of the first individual flow path 12 connected to the first common flow path 20 on the first common flow path 20 side is affected by the pressure loss, and the first individual flow path in the first common flow path 20 is affected. It depends on the position of 12. The pressure applied to the portion on the side of the second individual flow path 14 connected to the second common flow path 24 changes depending on the position of the second individual flow path 14 in the second common flow path 24 due to the influence of the 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 due to the arrangement of each of the first individual flow paths 12 and each of the second individual flow paths 14 acts to cancel out, and the difference in pressure applied to each discharge hole 8 can be reduced. Both the opening 20a of the first common flow path 20 and the opening 24a of the second common flow path 24 are open to the pressurizing chamber surface 4-1.

In the non-discharging state, the liquid meniscus is held in the discharge hole 8. Since the pressure of the liquid in the discharge hole 8 is negative (a state in which the liquid is about to be drawn into the first flow path member 4), the meniscus can be held in balance with the surface tension of the liquid. If the positive pressure increases, the liquid overflows, and if the negative pressure increases, the liquid is drawn into the first flow path member 4, and the state in which the liquid can be discharged cannot be maintained. Therefore, it is necessary to prevent the difference in the pressure of the liquid in the discharge hole 8 from becoming too large when the liquid is flowed from the second common flow path 24 to the first common flow path 20.

The wall surface of the first common flow path 20 on the discharge hole surface 4-2 side is the 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 makes the first damper 28A deformable, and the volume of the first common flow path 20 can be changed by deforming the first damper 28A. 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 flow path 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 fluctuates the discharge characteristics of the liquid. Sometimes. When the first damper 28A is present, the vibration of the liquid transmitted to the first common flow path 20 causes the first damper 28A to vibrate and be attenuated, so that the vibration of the liquid in the first common flow path 20 is difficult 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 the liquid.

The wall surface of the second common flow path 24 on the pressurizing chamber surface 4-1 side is the 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. Similar 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 the liquid.

The pressurizing chamber 10 is arranged so as to face the pressurizing chamber surface 4-1. The pressurizing chamber main body 10a that receives the pressure from the displacement element 50 and the discharge hole surface 4-from below the pressurizing chamber main body 10a. It is a hollow region including a descender 10b which is a partial flow path connected to the discharge hole 8 opened in 2. The pressurizing chamber main body 10a has a right cylindrical shape and a planar shape of a circular shape. Since the planar shape is circular, the amount of displacement 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 having a diameter smaller than that of the pressurizing chamber main body 10a, and has a circular cross-sectional shape. Further, the descender 10b is arranged at a position where it fits in 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 pressurizing chambers 10 form a plurality of pressurizing chamber rows 11A along the first direction. In each pressurizing chamber row 11A, the pressurizing chambers 10 are arranged at substantially equal intervals. The pressure chambers 10 belonging to the adjacent pressure chamber rows 11A are arranged in the first direction with a deviation of half of the above interval. In other words, the 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.

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

In the present embodiment, the first common flow path 20 has 51 lines, the second common flow path 24 has 50 lines, and the pressurizing chamber row 11A has 100 rows. (Here, the dummy pressurizing chamber row 11D composed of only the dummy pressurizing chamber 10D described later is not included in the number of the above-mentioned pressurizing chamber rows 11A. Further, the dummy is directly connected. The second common flow path 24, which is only the pressurizing chamber 10D, is not included in the number of the second common flow paths 24 described above.) Further, each pressurizing chamber row 11A includes 16 pressurizing chambers 10. It has been. As described above, since the pressurizing chambers 10 are arranged in a staggered pattern, the number of rows of the pressurizing chamber rows 11B is 32.

The plurality of pressurizing chambers 10 are arranged in a grid pattern along the first direction and the second direction on the discharge hole surface 4-2. The plurality of discharge holes 8 form a plurality of discharge hole rows 9A along the first direction. The discharge hole row 9A and the pressurizing 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 arranged so as to be offset in the first direction. Within one pressurizing chamber row 11A, the shifting directions are the same, and in the adjacent pressurizing chamber rows 11A, the shifting directions are opposite. As a result, the discharge holes 8 connected to the pressure chambers 10 belonging to the two pressure chamber rows 11B constitute one row of discharge hole rows 9B arranged along the second direction.

Therefore, in the present embodiment, the discharge hole columns 9A are 100 columns and the discharge hole rows 9B are 16 rows.

The area center of gravity of the pressurizing chamber main body 10a and the discharge hole 8 connected to the pressurizing chamber main body 10a are substantially displaced in the first direction. The descender 10b is arranged at a position deviated from the pressurizing chamber main body 10a in the direction of the discharge hole 8. 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, whereby it is possible to prevent the liquid from staying in the pressurizing chamber main body 10a.

The discharge hole 8 is arranged at the center of the descender 10b. Here, the central portion is a region within a circle that is half the diameter of the descender 10b, centered on the center of gravity of the area 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 side opposite to the descender 10b with respect to the area center of gravity of the pressurizing chamber main body 10a. As a result, the liquid flowing from the descender 10b flows after spreading over the entire pressurizing chamber main body 10a and toward the first individual flow path 12, so that the liquid is unlikely to stay in the pressurizing chamber main body 10a.

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

The angle formed by the first direction and the second direction (longitudinal direction of the head body 2a) deviates from a right angle. Therefore, the discharge holes 8 belonging to the discharge hole rows 9A arranged along the first direction are arranged so as to be displaced in the second direction by the angle deviated from the right angle. Since the discharge hole rows 9A are arranged side by side in the second direction, the discharge holes 8 belonging to different discharge hole rows 9A are arranged so as to be displaced in the second direction by that amount. Together, the discharge holes 8 of the first flow path member 4 are arranged side by side at regular intervals in the second direction so that the pixels formed by the discharged liquid fill a predetermined range. Can print.

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

In the present embodiment, the arrangement of the discharge holes 8 is as follows. In FIG. 3, when the discharge holes 8 are projected in a direction orthogonal to the second direction, 32 discharge holes 8 are projected in the range of the virtual straight line R, and the discharge holes 8 are arranged at intervals of 360 dpi in the virtual straight line R. .. As a result, if the printing paper P is conveyed and printed in the direction orthogonal to the virtual straight line R, printing can be performed at a resolution of 360 dpi. The discharge holes 8 projected in the virtual straight line R belong to all the discharge holes 8 (16 pieces) belonging to the discharge hole row 9A in one row and the two discharge hole rows 9A located on both sides of the discharge hole row 9A. There are 8 half (8 pieces) of discharge holes. In each discharge hole row 9B, the discharge holes 8 are lined up 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 lines as long as the discharge holes 8 are lined up in a straight line, and the straight lines are displaced in parallel between the discharge holes 8. In the first common flow path 20 and the second common flow path 24, since there are few deviations, the flow path resistance is small. Further, since the portion that is displaced in parallel is arranged at a position that does not overlap with the pressurizing chamber 10, the fluctuation of the discharge characteristic can be reduced for each pressurizing chamber 10.

The pressurizing chamber row 11A in one row (ie, two rows in total) at both ends in the second direction includes a normal pressurizing chamber 10 and a first dummy pressurizing chamber 10D (hence, this). The pressurizing chamber row 11A may be referred to as a dummy pressurizing chamber row 11D). Further, further outside the dummy pressurizing chamber row 11D, one row (that is, two rows in total at both ends) in which only the dummy pressurizing chamber 10D is lined up is arranged. The flow paths, one at each end in the second direction (that is, two in total), have the same shape as the normal first common flow path 24, but are directly different from the pressurizing chamber 10. It is not connected and is only connected to the dummy pressurizing chamber 10D.

The first flow path member 4 is an end flow path 30 extending in the first direction at a position outside the second direction of the common flow path group including the first common flow path 20 and the second common flow path 24. have. The end flow path 30 is lined up with the opening 30c arranged outside the opening 20a of the first common flow path 20 arranged on the pressurizing chamber surface 4-1 and the pressurizing chamber surface 4-1. It is a flow path connecting the opening 30d arranged outside the opening 24a of the second common flow path 24, and the flow path resistance of the end flow path 30 is common to the first common flow path 20 and the second common flow path 20. It is smaller than the flow path resistance of the flow path 24. The end flow path 30 will be described 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 is common to the second integrated flow path 26 that supplies the liquid to the second common flow path 24. It has a first integrated flow path 22 that collects the liquid in the flow path 20. The thickness of the second flow path member 6 is thicker than that of the first flow path member 4, and is about 5 to 30 mm.

The second flow path member 6 is joined in a region where the piezoelectric actuator substrate 40 on the pressurizing chamber surface 4-1 of the first flow path member 4 is not connected. More specifically, they are joined so as to surround the piezoelectric actuator substrate 40. By doing so, it is possible to prevent a part of the discharged liquid from adhering to the piezoelectric actuator substrate 40 as mist. Further, since the first flow path member 4 is fixed on the outer periphery, it is possible to prevent the first flow path member 4 from vibrating with the driving of the displacement element 50 and causing resonance or the like.

Further, a through hole 6c penetrates vertically in the central portion 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. The first flow path member 4 side of the through hole 6c is a widening portion 6ca whose width in the lateral direction is widened, and the wiring member extending from the piezoelectric actuator substrate 40 to both sides in the lateral direction is widened. It is bent by the portion 6ca, heads upward, and passes through the through hole 6. The convex portion of the portion extending over the widened portion 6ca may damage the wiring member, so it is preferable to make the convex portion R-shaped.

By arranging the first integrated flow path 22 in the second flow path member 6 which is thicker than the first flow path member 4 and separate from the first flow path member 4, the cross-sectional area of the first integrated flow path 22 is 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 accurately, the flow path resistance in 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 common flow path 20. It is preferably 1/100 or less.

By arranging the second integrated flow path 26 in the second flow path member 6 which is thicker than the first flow path member 4 and separate from the first flow path member 4, the cross-sectional area of the second integrated flow path 26 is 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 accurately, the flow path resistance in the range connected to the first integrated flow path 22 in the second integrated flow path 26) is the flow path resistance of the second common flow path 24. It is preferably 1/100 or less.

The first integrated flow path 22 is arranged at one end of the second flow path member 6 in the lateral direction, and the second integrated flow path 26 is arranged at the other end of the second flow path member 6 in the lateral direction. Each flow path is directed toward the first flow path member 4, 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 used with the first flow path member 4 The outer circumference of the wiring member can be fixed to increase the rigidity, and a through hole 6c through which the wiring member passes can be provided.

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

A plurality of first connection flow paths 22b extend downward (in the direction of the first flow path member 4) from the groove serving as the first integrated flow path main body 22a, and open on the pressurizing chamber surface 4-1. It is connected to the opening 20a of the first common flow path. Each of the first connection flow paths 22b is separated by a partition 6ba (that is, the first common flow path 20 side of the first connection flow path 22b is branched). As a result, the rigidity of the connection between the second flow path member 6 and the first flow path member 4 can be increased. Further, in the second direction, the length of the partition 6ba is longer than the length of the first connection flow path 22b, so that the rigidity of the connection between the second flow path member 6 and the first flow path member 4 is increased. Can be high.

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

The plate 6a is provided with an opening 22c at one end of the first integrated flow path 22 in the second direction. The plate 6a is provided with an opening 26c at the other end of the second integrated flow path 26 in the second direction. 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, but the supply and recovery may be reversed.

Dampers 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 discharge amount of the liquid. Further, by providing a filter in the first integrated flow path 22 and the second integrated flow path 26, it may be difficult for foreign matter and air bubbles to enter the first flow path member 4.

A piezoelectric actuator substrate 40 including a displacement element 50 is joined to a pressurizing chamber surface 4-1 which is an upper surface of the first flow path member 4, so that each displacement element 50 is located on the pressurizing chamber 10. Have been placed. The piezoelectric actuator substrate 40 occupies a region having substantially the same shape as the pressurizing chamber group formed by the pressurizing chamber 10. Further, the openings of the respective pressurizing chambers 10 are 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 long in the same direction as the head body 2a. Further, a signal transmission unit such as an FPC for supplying a signal to each displacement element 50 is connected to the piezoelectric actuator substrate 40. The second flow path member 6 has a through hole 6c penetrating up and down in the center, and the signal transmission unit is electrically connected to the control unit 88 through the through hole 6c. The signal transmission unit has a shape extending in the lateral direction from one long side end of the piezoelectric actuator substrate 40 toward the other long side end, and the wiring arranged in the signal transmission unit extends along the lateral direction. It is preferable to extend the wires and arrange them in the longitudinal direction because it is easy to keep a 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 flow path member 4 has a laminated structure in which a plurality of plates are laminated. Twelve plates from the plate 4a to the plate 4l are laminated in order from the pressure chamber surface 4-1 side of the flow path member 4. Many holes and grooves are formed in these plates. Holes and grooves can be formed, for example, by making each plate out of metal and etching. The thickness of each plate is 10 to 300 μ
When it is about m, the accuracy of forming the holes to be formed can be increased. The plates 4f to i are plates having the same shape, and they may be composed of one plate, but they are composed of four plates in order to form holes with high accuracy. The plates are aligned and laminated so that these holes communicate with each other to form a flow path such as the first common flow path 20.

The pressurizing chamber main body 10a is open to the pressurizing chamber surface 4-1 of the flat plate-shaped flow path member 4, and the piezoelectric actuator substrate 40 is joined to the pressurizing chamber main body 10a. Further, the pressurizing chamber surface 4-1 has an opening 24a for supplying the liquid to the second common flow path 24 and an opening 20a for collecting the liquid from the first common flow path 20. A discharge hole 8 is opened in the discharge hole surface 4-2, which is a surface of the flow path member 4 opposite to the pressure chamber surface 4-1. A plate may be further laminated on the pressure chamber surface 4-1 to close the opening of the pressure chamber main body 10a, and the piezoelectric actuator substrate 40 may be bonded thereto. By doing so, the possibility that the discharged liquid comes into contact with the piezoelectric actuator substrate 40 can be reduced, and the reliability can be further increased.

The structure for discharging the 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 cross-sectional area smaller than that of the pressurizing chamber main body 10a. The pressurizing chamber main body 10a is formed on the plate 4a, and the descender 10b is formed by overlapping the holes formed in the plates 4b to k, and is further closed by the nozzle plate 4l (the portion other than the discharge hole 8). It is made up.

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

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

To summarize the flow of the liquid, 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 liquids are discharged. It is discharged from the discharge hole 8. The liquid that has not been discharged enters the first common flow path 20 through the first individual flow path 12, then enters the first integrated flow path 22, and is discharged to the outside of the head main body 2.

The piezoelectric actuator substrate 40 has a laminated structure composed of two piezoelectric ceramic layers 40a and 40b, which are piezoelectric materials. Each of these piezoelectric ceramic layers 40a and 40b has a thickness of about 20 μm. That is, the thickness from the upper surface of the piezoelectric ceramic layer 40a of the piezoelectric actuator substrate 40 to the lower surface of the piezoelectric ceramic layer 40b is about 40 μm. The thickness ratio of the piezoelectric ceramic layer 40a to the piezoelectric ceramic layer 40b is 3: 7 to 7: 3, preferably 4: 6 to 6: 4. Each of the piezoelectric ceramic layers 40a and 40b extends so as to straddle the plurality of pressure chambers 10. The piezoelectric ceramic layers 40a, 40b may, for example, strength with a dielectric, lead zirconate titanate (PZT), NaNbO ₃ system, BaTiO ₃ system, (BiNa) NbO ₃ system, such as BiNaNb ₅ O ₁₅ system Made of ceramic material.

The piezoelectric actuator substrate 40 has a common electrode 42 made of a metal material such as Ag-Pd and an individual electrode 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 electrode 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 have an individual electrode body 44a whose planar shape is one size smaller than that of the pressurizing chamber body 10a and which has a shape substantially similar to that of the pressurizing chamber body 10a, and an extraction electrode drawn from the individual electrode body 44a. 44b and is included. A connection electrode 46 is formed at one end of the extraction electrode 44b, which is drawn out of the region facing the pressurizing chamber 10. The connection electrode 46 is a conductive resin containing conductive particles such as silver particles, and is formed to have a thickness of about 5 to 200 μm. Further, the connection electrode 46 is electrically joined to an electrode provided in the signal transmission unit.

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

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

The common electrode 42 is formed in a region between the piezoelectric ceramic layer 40a and the piezoelectric ceramic layer 40b over substantially the entire surface direction. That is, the common electrode 42 extends so as to cover all the pressurizing chambers 10 in the region 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 an electrode group composed of individual electrodes 44 via a via hole formed through the piezoelectric ceramic layer 40a. It is grounded and held at the ground potential. The surface electrode for the common electrode is directly or indirectly connected to the control unit 88, like the plurality of individual electrodes 44.

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

Next, the liquid discharge operation will be described. The displacement element 50 is driven (displaced) by a drive signal supplied to the individual electrodes 44 via a driver IC or the like under the control of the control unit 88. In the present embodiment, the liquid can be discharged by various drive signals, but here, a so-called pulling drive method will be described.

The individual electrode 44 is 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 electrode 44 is once set to the same potential as the common electrode 42 (hereinafter referred to as low potential). After that, 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) shapes (beginning) at the timing when the individual electrodes 44 become low potentials, and the volume of the pressurizing chamber 10 is in the initial state (the potentials of both electrodes are different). State) increases compared to. As a result, a negative pressure is applied to the liquid in the pressurizing chamber 10. Then, the liquid in the pressurizing chamber 10 starts to vibrate in the natural vibration cycle. Specifically, at first, the volume of the pressurizing chamber 10 begins to increase, and the negative pressure gradually decreases. The volume of the pressurizing chamber 10 is then maximized and the pressure is almost zero. Then the volume of the pressurizing chamber 10 begins to decrease and the pressure increases. After that, the individual electrode 44 is set to a high potential at the timing when the pressure becomes almost maximum. Then, the vibration applied first and the vibration applied next overlap, and a larger pressure is applied to the liquid. This pressure propagates in the descender and discharges the liquid from the discharge hole 8.

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

The head body 2a is controlled to keep the temperature constant in order to stabilize the liquid discharge characteristics. Further, the lower the viscosity of the liquid, the more stable the discharge and the circulation of the liquid, so that the temperature is basically set to room temperature or higher. Therefore, it is basically heated, but if the environmental temperature is high, it may be cooled. The case of heating with respect to the environmental temperature will be described below, but the same applies to the case of cooling.

In order to keep the temperature constant, the liquid discharge head 2 is provided with a heater, or the liquid to be supplied is temperature-controlled. In any case, if there is a difference between the ambient temperature and the target temperature, heat is dissipated from the end of the head body 2a in the longitudinal direction (second direction), so that it is located in the center of the second direction. The temperature of the pressurizing chamber 10 located at the end in the second direction and the end 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 of the pressurizing chambers 10 or the temperature of the displacement element 50, they cause a difference in the ejection characteristics of the droplets, which may reduce the printing accuracy.

The details of this embodiment will be described with reference to FIG. 6A. The pressurizing chamber arrangement area 11C is an area in which the pressurizing chamber 10 is arranged. More specifically, it is the region having the smallest area among the convex regions including all the pressurizing chambers 10 existing in the head body 2a. FIG. 6A shows a schematic parallelogram region.

The first integrated flow path 22 is arranged in the first direction with respect to the pressurizing chamber arrangement region 11C in the range where the pressurizing chamber 10 exists (that is, the range of the pressurizing chamber arrangement region 11C) at least in the second direction. It contains 22 g of the first extending portion. 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 the first end portion 22h which is a part of the first integrated flow path 22. The first end portion 22h is arranged so as to extend in the second direction from the pressurizing chamber arrangement region 11C.

The second integrated flow path 26 is a pressurizing chamber arrangement region in a range in which the pressurizing chamber 10 exists (that is, a range of the pressurizing chamber arrangement region 11C) at least in the fourth direction (direction opposite to the second direction). It contains 26 g of a second extending portion arranged in a third direction (direction opposite to the first direction) with respect to 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 the second end portion 26h which is a part of the second integrated flow path 26. The second end portion 26h is arranged so as to extend in the fourth direction from 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 warmed. Further, the heat spreads from the warmed portion to the surroundings by heat conduction, and the entire head body 2a is warmed.

Since the end portion of the head body 2a in the second direction and the end portion in the fourth direction have a large surface area due to the short side of the head body 2a when viewed in a plan view, heat can easily escape, and the end portion of the head body 2a in the second direction The temperature tends to be lower than that in the central part. Further, the end portion of the head body 2a in the second direction and the end portion in the fourth direction are often portions to be attached to the printer, and the temperature is lowered by heat transfer to the printer.

At the end of the head body 2a in the second direction, the 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 form the first end. It is joined below 22h. Therefore, the heat of the liquid flowing through the first end portion 22h is transferred 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 the present embodiment, the second flow path member 6 below the first end portion 22h is solid without any gaps such as for a damper. As a result, the thermal conductivity is increased, so that the temperature of the first flow path member 4 can be made more uniform. It should be noted that the solid content referred to here may include minute voids having a width of 1 mm or 500 μm or less and a depth of 500 μm or less, such as an adhesive relief groove. 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.

Further, if the lower surface of the first end portion 22h is the upper surface (pressurizing chamber surface 4-1) of the first flow path member 4, the heat of the liquid flowing through the first end portion 22h will be the first. By directly transmitting from the 2 flow path member 6 to the 1st flow path member 4, the temperature of the 1st flow path member 4 can be made more uniform because the transmission becomes easier. In this case, the first end portion 22h is formed in a groove-like structure that opens below the second flow path member 6, and by joining the first flow path member 4 to the second flow path member 6, the first end portion 22h is formed. The groove is closed by the first flow path member 4 to form a tubular first end portion 22h.

Further, the flow path of the first end portion 22h is directed downward (first flow path member 4), connected to the flow path once provided in the first flow path member 4, and again in the second flow path member 6. After connecting to the flow path of, it may be connected to the outside through the opening 22c.

At the end of the head body 2a in the fourth direction, the 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 form the second end. It is joined below 26h. Therefore, the heat of the liquid flowing through the second end portion 26h is transferred 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 the present embodiment, the second flow path member 6 below the second end portion 26h is solid. As a result, the thermal conductivity is high, so that 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.

Further, if the lower surface of the second end portion 26h is the upper surface (pressurizing chamber surface 4-1) of the first flow path member 4, the heat of the liquid flowing to the second end portion 26h will be the second. By directly transmitting from the 2 flow path member 6 to the 1st flow path member 4, the temperature of the 1st flow path member 4 can be made more uniform because the transmission becomes easier.

Further, the flow path of the second end portion 26h is once connected to the flow path provided in the first flow path member 4, and then connected to the flow path in the second flow path member 6 again, and then externally connected through the opening 26c. You may try to connect with.

The structure of the second flow path member 6 and the first flow path member 4 in the vicinity of the first end portion 22h and the second end portion 26h is not only below the first end portion 22h and the second end portion 26h, but at least the first. Somewhere in the range where the first end 22h and the second end exist in the two directions, a solid part is provided in the lateral direction of the head body 2a to equalize the temperature. On the other hand, it is preferable.

The first end portion 22h not only extends in the second direction from the pressurizing 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 less likely to be transmitted to the pressurizing chamber arrangement region 11C. Here, extending in the third direction means extending in the third direction instead of the first direction, and more specifically, it 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 pressurizing chamber arrangement region 11C, it is difficult for the influence from the end portion of the head body 2a in the second direction to be transmitted to the pressurizing chamber arrangement region 11C. can. Extending in the third direction from the center of the pressurizing chamber arrangement region 11C means that there is a portion of the pressurizing chamber arrangement region 11C located in the third direction from the center in the direction orthogonal to the second direction. It means that. Specifically, as shown in FIG. 6B, the first end portion 122h is located in the third direction from the virtual straight line L1 indicating the center of the pressure chamber arrangement region 11C in the direction orthogonal to the second direction. It shows that there is a part that is.

Similarly, for the second end portion 26h, if the second end portion 26h extends in the first direction from the center of the pressurizing chamber arrangement region 11C, the influence from the end portion of the head body 2a in the fourth direction is exerted. , It can be difficult to transmit to the pressurizing chamber arrangement area 11C. In FIG. 6B, there is a portion where the first end portion 126h is located in the first direction with respect to the virtual straight line L1 indicating the center of the pressure chamber arrangement region 11C in the direction orthogonal to the second direction. Shows the morphology.

Further, as shown in FIG. 6C, if the first end portion 222h extends in the third direction from the pressurizing chamber arrangement region 11C, the influence from the end portion of the head body 2a in the second direction is exerted. , The pressure chamber arrangement area 11C makes it difficult to transmit. Extending in the third direction from the pressurizing chamber arrangement region 11C means that the pressure chamber arrangement region 11C is located in the third direction from the farthest virtual straight line L2 in the direction orthogonal to the second direction. It means that there is a part.

Similarly for the second end portion 26h, as shown in FIG. 6C, if the second end portion 226h extends in the first direction from the pressurizing chamber arrangement region 11C, the fourth head body 2a The influence from the end of the direction can be made difficult to be transmitted by the pressurizing chamber arrangement region 11C. Extending in the first direction from the pressurizing chamber arrangement region 11C means that the pressure chamber arrangement region 11C is located in the first direction from the farthest virtual straight line L3 in the direction orthogonal to the second direction. It means that there is a part.

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 the second two opposing sides of the rectangular shape, which are different from the first two opposing sides. And the inclination is toward the second direction. As a result, the pressurizing chamber 10 arranged at the end in the second direction is arranged in the fourth direction at the end in the third direction rather than 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, it is a portion of the head body 2a that is more susceptible to the temperature of the end in the second direction, and since that portion is recessed in the fourth direction, it can be less affected by the temperature. Since the relationship of such arrangement is the same at the end in the fourth direction, it can be less affected by the temperature even at the end in the fourth direction.

The first extending portion 22g extends in the second direction along the pressurizing chamber arrangement region 11C. The first extending portion 22g preferably extends over at least the side on the first direction side of the pressurizing chamber arrangement region 11C. Thereby, the temperature of the pressurizing chamber arrangement region 11C can be more equalized. If the first extending portion 22g extends in the fourth direction from the side of the pressurizing chamber arrangement region 11C on the first direction side, it is affected by the temperature from the end portion of the head body 2a in the fourth direction. It is preferable because it becomes difficult to handle. However, even if the portion extends in the fourth direction from the opening 20a of the first common flow path 20, the portion deviates from the circulation path of the liquid, so that the liquid does not change much and the contribution to temperature equalization is also compared. Small. In addition, the retention of the liquid may cause an effect that the pigment in the liquid tends to settle.

Therefore, the end flow path 30 is provided on the fourth direction side of the pressure chamber arrangement region 11C of the flow path member 4. The opening 30c of the end flow path 30 is arranged on the fourth direction side of the opening 20a of the first common flow path 20, and extends in the fourth direction from the opening 20a of the first common flow path 20. 1 The liquid flowing through the extending portion 22g can be made to circulate through the end flow path 30.

The same can be applied to the second extending portion 26 g. That is, the end flow path 30 is provided on the second direction side of the pressure chamber arrangement region 11C of the flow path member 4. The opening 30d of the end flow path 30 is arranged on the second direction side of the opening 24a of the second common flow path 24, and extends in the second direction from the opening 24a of the second common flow path 24. 2 The liquid flowing through the extending portion 26g can be made to circulate through the end flow path 30.

FIG. 7A is a schematic plan view of the head body of another embodiment of the present invention, and shows the same part as that of FIG. 6A. 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 portion 322h is the distance D11 [mm] along the second direction on the first direction side of the first end portion 322h. Is shorter than. As a result, the portion of the head body that is easily affected by the temperature of the end portion in the second direction due to the interruption on the third direction side of the first end portion 322h is the portion that is easily affected by the temperature of the first end portion 322h that is close in distance. Therefore, it can be made less susceptible to the influence of temperature.

The distance D21 [mm] along the second direction on the first direction side of the second end portion 326h is the distance D23 [mm] along the second direction on the third direction side of the second end portion 326h. Is shorter than. As a result, the portion that is easily affected by the temperature of the end portion in the fourth direction of the head body due to the interruption on the first direction side of the second end portion 326h is the second end portion 326h that is close in distance. Therefore, it can be made less susceptible to the influence of temperature.

FIG. 7B is a schematic plan view of the head body of another embodiment of the present invention, and shows the same part as that of FIG. 6A.

The distance D1 [mm] along the second direction between the first end portion 422h and the pressurizing chamber arrangement region 11C is along the second direction between the second end portion 426h and the pressurizing chamber arrangement region 11C. It 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 collected to the outside. Therefore, after passing through the second end portion 426h, the liquid whose temperature has dropped passes through the first end portion 422h. Therefore, by arranging as described above, even if the temperature of the liquid passing through the first end portion 422h is slightly lowered, the difference can hardly affect the pressure chamber arrangement region 11C.

The distance D1 [mm] along the second direction between the first end portion 422h and the pressurizing chamber arrangement region 11C is along the second direction between the first end portion 422h and the pressurizing chamber arrangement region 11C. It is the average distance of the distance. More specifically, the distance D1 [mm] is a distance along the second direction in the 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 portion 422h and the first direction side of the first end portion 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 pressurizing chamber arrangement region 11C is along the second direction between the second end portion 426h and the pressurizing chamber arrangement region 11C. It is the average distance of the distance. In FIG. 7B, the distance D2 [mm] is the distance D21 [mm] along the second direction on the first direction side of the second end portion 426h and the third direction side of the second end portion 426h. Is the arithmetic average of the distance D23 [mm] along the second direction.

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

The cross-sectional area of the first end portion 522h is smaller on the downstream side of the opening to the outside than on the upstream side of the first extending portion. Further, the cross-sectional area of the second end portion 526h is smaller on the downstream side of the second extending portion than on the upstream side of the opening to the outside. Therefore, the average cross-sectional area of the first end portion 522h is smaller than the average cross-sectional area of the second end portion 526h. Since the liquid has a smaller thermal conductivity than the second flow path member 6, the heat loss to the outside due to the heat conduction can be reduced in the thick portion. As a result, it is possible to suppress the temperature drop on the downstream side where the temperature drop becomes large.

In the head main body 2a, end flow paths 30 are provided on the outside of the first flow path member 4 in the second direction and the outside of the fourth direction of the pressure chamber arrangement region 11C. The end flow path 30 has a lower flow path resistance than the common flow path (the first common flow path 20 and the second common flow path). Since the flow path resistance of the end flow path 30 is low, the flow rate of the liquid flowing in the end flow path 30 per hour is larger than the flow rate of the liquid flowing in the common flow path per hour. Therefore, even if the heat radiation from the end portion of the head body 2a in the second direction is large, the temperature is difficult to be transmitted so as to cross the end flow path 30, so that the temperature difference in the pressurizing chamber arrangement region 11C can be reduced. The flow path resistance of the common flow path is preferably twice or more, particularly three times or more, of the flow path resistance of the end flow path 30.

Further, not only can the temperature drop be suppressed by 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 staying in the first flow path 30 so that the first extension is prevented. The portion 22g can be extended and arranged on the fourth direction side, and the second extending portion 26g can be extended and arranged on the second direction side so that the liquid is less likely to stay.

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 the present embodiment, the liquid supplied to one second common flow path 24 flows into the pressurizing chambers of the two rows of pressurizing chamber rows 11A, and further flows into the two first common flow paths 20. On the contrary, the liquid from the two second common flow paths 24 flows into the one first common flow path 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 pressurizing chamber of the two rows of pressurizing chamber rows 11A, and further, the first common flow path It becomes the same as the flow path resistance when flowing into the flow path resistance twice that of 20. That is, the flow path resistance of the common flow path is the flow path resistance of the second common flow path 24 + (flow path resistance of the individual flow path / 16 + flow path resistance of the first common flow path 24 × 2) / 2. The flow path resistance of the first common flow path 20 + the flow path resistance of the second common flow path 24 + the flow path resistance of the individual flow paths / 32, and the flow path resistance of the first common flow path 20 + the second common flow path. It is the flow path resistance of 24 + 2 rows of pressurizing chamber rows 11A.

In the present embodiment, the end flow paths 30 are provided on both sides of the pressurizing chamber arrangement region 11C, respectively, and it is better to provide them on both sides for temperature stabilization. The temperature can be stabilized on one side of it.

When the head body 2a and the printer 1 are fixed 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 becomes large. 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. Has been done. One surface of the third damper 28C faces the wide portion 30a, and the other surface faces the damper chamber 29, so that the third damper 28C can be deformed. The damping ability of the damper is greatly affected by the part where the crossing of the deformable area is the narrowest. Since the size of the head body 2a that widens the width of the common flow path becomes large, the width of the common flow path cannot be increased so much, and only the first damper 28A and the second damper 28B provided in the common flow path are used. , Damping ability may not be sufficient. By increasing the width of the wide portion 30a, the damping capacity of the third damper 28C can be increased. The width of the wide portion 30a is preferably twice as large as, particularly three times or more as wide as the width of the common flow path.

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

Further, in the above embodiment, 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. The invention is not limited to such a form. That is, the common flow path may directly connect the first integrated flow path 22 and the second integrated flow path 26.

Further, in the above embodiment, by allowing the liquid to pass through the head body 2a, the liquid circulates in the entire printer 1, but the first integrated flow path 22 and the second integrated flow path 22 The liquid may be supplied from both of the 26 and used without circulation.

Further, the first integrated flow path 22 and the second integrated flow path 26 may be arranged in the first flow path member 4 instead of being arranged in the second flow path 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 in the first flow path member 4. And the temperature in the plane direction can be more averaged. However, if an attempt is made to flow a liquid for printing and a liquid for suppressing retention and enabling temperature control to flow through the first integrated flow path 22 and the second integrated flow path 26, the first flow path member 4 The height of the cross section of the first integrated flow path 22 and the second integrated flow path 26 is increased, or the size of the head body 2a in the lateral direction is increased to increase the size of the first integrated flow path 22. It is necessary to increase the width of the cross section of the flow path 22 and the second integrated flow path 26. In the former case, it may be difficult to increase the drive frequency due to the lengthening of AL, and in the latter case, the head body 2a becomes large, so that the interval when using a plurality of head bodies 2a becomes wide. Printing accuracy may be low. Therefore, it is preferable that the first integrated flow path 22 and the second integrated flow path 26 are arranged in the second flow path member 6.

1 ... Printer 2 ... Liquid discharge head 2a ... Head body 4 ... First flow path member 4a to 4l ... Plate (of first flow path member) 4-1 ... Pressurization Chamber surface 4-2 ... Discharge hole surface 6 ... Second flow path member 6a, 6b ... Plate 6ba, 6bb ... (second flow path member) ... Partition 6c ... (Second flow) Through hole 6ca ・ ・ ・ Widening part of through hole 8 ・ ・ ・ Discharge hole 9A ・ ・ ・ Discharge hole row 9B ・ ・ ・ Discharge hole line 10 ・ ・ ・ Pressurization chamber 10a ・ ・ ・ Pressurization chamber body 10b ... Partial flow path (descender)
10D ... Dummy pressurizing chamber 11A ... Pressurizing chamber row 11B ... Pressurizing chamber line 11C ... Pressurizing chamber arrangement area 12 ... 1st individual flow path 14 ... 2nd individual flow Road 20 ... 1st common flow path (common flow path)
20a ... (1st common flow path) opening 22 ... 1st integrated flow path 22a ... 1st integrated flow path main body 22b ... 1st connection flow path 22c ... (1st integrated flow path) (Road) opening 22g ・ ・ ・ 1st extending part 22h ・ ・ ・ 1st end part 24 ・ ・ ・ 2nd 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 ・ ・ ・ 2nd extension part 26h ・ ・ ・ 2nd end part 28A ・ ・ ・ 1st damper 28B ・ ・ ・ 2nd damper 28C ・ ・ ・ 3rd damper 29 ・ ・ ・ Damper room 30 ・・ ・ End flow path 30a ・ ・ ・ Wide part 30b ・ ・ ・ Constricted part 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 ... Drawer electrode 46 ... Connection electrode 50 ... Displacement element (pressurizing part)
60 ... Signal transmission unit 70 ... (with head) Frame 72 ... Head group 80A ... Paper feed roller 80B ... Recovery roller 82A ... Guide roller 82B ... Conveyor roller 88 ...・ Control unit P ・ ・ ・ Printing paper

Claims (18)

A first flow path member having a plurality of discharge holes and a plurality of pressure chambers connected to the plurality of discharge holes, a first integrated flow path for collecting liquid from the plurality of pressure chambers, and the plurality of pressure chambers. A second flow path member laminated on the first flow path member having a second integrated flow path for supplying a liquid to the pressurizing chamber, and a plurality of pressurizations for pressurizing the plurality of pressurizing chambers, respectively. It is a liquid discharge head that includes a part,
When viewed in a plane
The plurality of pressure chambers are arranged in the pressure chamber arrangement area, and the plurality of pressure chambers are arranged in the pressure chamber arrangement area.
The first integrated flow path is arranged in the first direction with respect to the pressurizing chamber arrangement region, includes a portion extending in the second direction intersecting the first direction, and pressurizes. It includes the first end portion that is arranged in the second direction with respect to the chamber arrangement area.
The second integrated flow path is arranged in a third direction opposite to the first direction and extends in a fourth direction opposite to the second direction with respect to the pressurizing chamber arrangement region. A portion is included, and a second end portion that is arranged in the fourth direction from the pressurization chamber arrangement region is included.
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. Is 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. Is either
The pressurizing chamber has a pressurizing chamber main body and a descender connecting the pressurizing chamber main body and the discharge hole.
A first individual flow path connected to the pressurizing chamber and through which a liquid collected from the pressurizing chamber to the first integrated flow path passes.
A second individual flow path connected to the pressurizing chamber and through which the liquid supplied from the second integrated flow path to the pressurizing chamber passes.
Have and
The distance from the connection position between the pressure chamber and the first individual flow path to the discharge hole, the different and the distance to the discharge hole from the connection position between the second individual flow path and the pressure chamber Yes ,
A liquid discharge head characterized by that. The liquid discharge head according to claim 1, wherein the second individual flow path is connected to the descender. The liquid discharge head according to claim 1 or 2, wherein the second flow path member located below the first end portion and the second end portion is solid. When viewed in a plan view, the first end portion extends in a direction between the third direction and the second direction, and the angle formed by the third direction and the second direction is an acute angle. The liquid discharge head according to any one of claims 1 to 3. The liquid discharge head according to claim 4, wherein the first end portion extends in the third direction from the central portion of the pressurizing chamber arrangement region when viewed in a plan view. When viewed in a plan view, the second end portion extends in a direction between the first direction and the fourth direction, and the angle formed by both the first direction and the fourth direction is an acute angle. The liquid discharge head according to any one of claims 1 to 5, wherein the liquid discharge head is provided. The liquid discharge head according to claim 6, wherein the second end portion extends in the first direction from the central portion of the pressurizing chamber arrangement region when viewed in a plan view. Claims 1 to 7 are characterized in that 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 when viewed in a plan view. The liquid discharge head according to any one of. The first flow path member is a plurality of common flows that connect the first integrated flow path and the plurality of pressurizing chambers, or connect the second integrated flow path and the plurality of pressurizing chambers. Including the road,
The liquid discharge head according to any one of claims 1 to 8, wherein the plurality of common flow paths extend in the first direction and are arranged in the second direction when viewed in a plan view. .. When viewed in a plane
The second flow path member has a rectangular shape and has a rectangular shape.
The second direction is substantially parallel to the first two opposing sides of the rectangular shape.
The ninth aspect of the present invention is characterized in that the first direction is inclined in the second direction as compared with the second two opposing sides having a rectangular shape, which is different from the first two opposing sides. The liquid discharge head described. A plurality of discharge holes, a plurality of pressure chambers connected to the plurality of discharge holes, and a flow path member having a first integrated flow path and a second integrated flow path connected to the plurality of pressure chambers. , A liquid discharge head including a plurality of pressurizing portions for pressurizing the plurality of pressurizing chambers, respectively.
When viewed in a plane
The plurality of pressure chambers are arranged in the pressure chamber arrangement area, and the plurality of pressure chambers are arranged in the pressure chamber arrangement area.
In the plane
The first integrated flow path is arranged in the first direction with respect to the pressurizing chamber arrangement region, includes a portion extending in the second direction intersecting the first direction, and pressurizes. It includes the first end portion that is arranged in the second direction with respect to the chamber arrangement area.
The second integrated flow path is arranged in a third direction opposite to the first direction and extends in a fourth direction opposite to the second direction with respect to the pressurizing chamber arrangement region. A portion is included, and a second end portion that is arranged in the fourth direction from the pressurization chamber arrangement region is included.
The pressurizing chamber has a pressurizing chamber main body and a descender connecting the pressurizing chamber main body and the discharge hole.
A first individual flow path connected to the pressurizing chamber and through which a liquid collected from the pressurizing chamber to the first integrated flow path passes.
A second individual flow path connected to the pressurizing chamber and through which the liquid supplied from the second integrated flow path to the pressurizing chamber passes.
Have and
The distance from the connection position between the pressure chamber and the first individual flow path to the discharge hole, the different and the distance to the discharge hole from the connection position between the second individual flow path and the pressure chamber Yes ,
A liquid discharge head characterized by that. The liquid discharge head according to claim 11, wherein the second individual flow path is connected to the descender. The liquid discharge head according to claim 11 or 12, wherein a portion located below at least one of the first end portion and the second end portion is solid. In the plane, the first end extends in a direction between the third direction and the second direction, and the angle formed by the third direction and the second direction is an acute angle. The liquid discharge head according to any one of claims 11 to 13. The liquid discharge head according to claim 14, wherein the first end portion extends in the third direction from the central portion of the pressurizing chamber arrangement region in the plane. In the plane, the second end extends in a direction between the first direction and the fourth direction, and the angle formed by both the first direction and the fourth direction is an acute angle. The liquid discharge head according to any one of claims 11 to 15. The liquid discharge head according to claim 16, wherein the second end portion extends in the first direction from the central portion of the pressurizing chamber arrangement region in the plane. The liquid discharge head according to any one of claims 1 to 17, a transport unit for transporting a recording medium to the liquid discharge head, and a control unit for controlling the liquid discharge head are provided. Recording device.

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