JP2004291543A - Ink jet printer head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet printer head which improves a printing quality by reducing a crosstalk between adjacent pressure chambers. <P>SOLUTION: A cavity unit obtained by laminating a plurality of plates, and a plate-like actuator 20 selectively drivable at respective pressure chambers 16-1, 16-2 and having extensively deformable active part 50 in a pressure chamber direction to inject an ink are laminated. A spacer plate 13 is provided at the opposite side to the actuator 20 via a base plate 14 adjacently formed to the pressure chambers aligned in a row state via a partition wall 14a. The thickness of the space plate 13 is set so that the bottom sectional change quantity Z2 of the pressure chamber 16-2 due to the deformation of the spacer plate 13 adjacent to the pressure chambers 16-1, 16-2 corresponding to selectively driven active part 50 and opposed to the pressure chamber 16-2 corresponding to the selectively driven active part 50, and the side sectional change quantity Z1 due to the deformations of a pair of partition walls 14a in association with the drive of the active part become substantially equal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flat cavity unit in which a plurality of plates are stacked, a pressure chamber and an ink flow passage are formed in the stacked plate, and a nozzle for ink ejection is formed on one surface (surface). The present invention relates to a structure of an ink jet printer head formed by joining a plate-type actuator disposed to a chamber.
[0002]
[Prior art]
Conventionally, in an on-demand type ink jet printer head, a plate type piezoelectric actuator formed by laminating piezoelectric layers is joined to a pressure chamber of a cavity unit so as to be joined, and the ink chamber is expanded and contracted by the expansion and contraction of the piezoelectric actuator. Ink jetting with a reduced volume is known (Patent Documents 1 and 2).
[0003]
In this case, as a cavity unit, for example, in Patent Document 1, a space is formed such that a pressure chamber functioning as an ink chamber is opened on one surface (upper side) of one plate, and ink is ejected on a lower surface side of the plate. Nozzles are formed, and the narrow sides of the pressure chambers arranged in the row direction of the nozzles are arranged adjacent to each other with a partition wall interposed therebetween. On the other hand, in Patent Document 2, the cavity unit is formed by laminating a plurality of plates on one surface (the side opposite to the piezoelectric actuator) of the base plate in which the pressure chamber is formed, and these plates are provided with the nozzle. A plate having a flow passage communicating from each pressure chamber to each nozzle, a plate having a common ink chamber formed therein for storing ink from an ink supply source and then refilling the pressure chamber.
[0004]
[Patent Document 1]
JP 2001-162796 A (see FIG. 1)
[Patent Document 2]
JP 2001-260349 A (see FIGS. 2 and 4)
[0005]
[Problems to be solved by the invention]
By the way, in the piezoelectric actuator, an electrode layer of an individual electrode that selectively applies a voltage to each of the ink chambers and an electrode layer of a common electrode that is electrically common to the plurality of ink chambers are made of a piezoelectric material. The piezoelectric layers, which are alternately arranged in the laminating direction of the piezoelectric layers and are sandwiched such that the individual electrodes and the common electrode face each other, become active portions that expand and contract by a voltage applied between the electrodes.
[0006]
When the active portion extends in the laminating direction of the piezoelectric layers, the volume of the pressure chamber at the position facing the active portion decreases. At this time, the partition on the narrow side of the pressure chamber is elastically deformed so that the side closer to the joint with the piezoelectric actuator falls down into the volume of the pressure chamber, in other words, the cross-sectional area of the pressure chamber is reduced. Then, the pressure chamber adjacent to the pressure chamber via the partition (the active portion corresponding to this pressure chamber is in the non-drive state) is close to the joint with the piezoelectric actuator in response to the collapse deformation of the partition. The side becomes larger than the cross-sectional area (volume) of the original pressure chamber.
[0007]
On the other hand, the bottom surface of the pressure chamber, that is, one plate or the laminated plate on the side opposite to the side on which the piezoelectric actuator is disposed is bent upward by elasticity so as to reduce the cross-sectional area (volume) of the pressure chamber. Will be.
[0008]
Due to such elastic deformation, the pressure chamber (non-ejection pressure chamber) adjacent to the pressure chamber from which the ink was ejected also expands its volume and then performs an operation of returning to its original state. This causes pressure fluctuations. After that, when the ejection operation is performed in the adjacent pressure chamber, the pressure fluctuation for the ejection is caused to be superimposed on the pressure fluctuation, so that the ink ejection speed and the droplet size are smaller than predetermined values. , Or so-called crosstalk. In particular, in the case of a pressure chamber (a non-ejection pressure chamber) sandwiched between two pressure chambers that have ejected ink, pressure fluctuations may be large and ink may be ejected undesirably.
[0009]
SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet printer head capable of solving such problems and improving print quality by devising the thickness and material of a plate constituting one surface of a pressure chamber. .
[0010]
[Means for Solving the Problems]
In order to achieve the above object, an ink jet printer head according to the invention according to claim 1, wherein a plurality of nozzles arranged in a row, pressure chambers arranged in a row corresponding to each nozzle, A cavity unit formed by stacking a plurality of plates each having a flow passage communicating with each of the nozzles, and a common ink chamber for storing ink from an ink supply source and then refilling the pressure chamber, and the pressure chamber In an ink jet printer head which is selectively drivable every time and has a plate-shaped actuator for ejecting ink having an active portion capable of expanding and contracting in the pressure chamber direction, the base plate has a longitudinal direction parallel to the base plate. The pressure chambers arranged in a row are formed so as to be adjacent to each other with a partition wall interposed therebetween, and are stacked on the opposite side of the base plate from the actuator. A pressure plate adjacent to the pressure chamber corresponding to the active part and facing the pressure chamber corresponding to the non-driven active part when the active part is selectively driven. The thickness of the spacer plate is set so that the amount of change in the bottom cross-section of the chamber and the amount of change in the side cross-section due to the deformation of the partition wall due to the driving of the active portion are substantially equal.
[0011]
According to a second aspect of the present invention, in the ink jet printer head according to the first aspect, a plate material of the base plate and the spacer plate is a 42% nickel alloy steel plate.
[0012]
According to a third aspect of the present invention, in the ink jet printer head according to the first or second aspect, the thickness of the spacer plate is set to approximately twice the thickness of the base plate.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view showing a piezoelectric type ink jet printer head according to an embodiment of the present invention, FIG. 2 is a perspective view showing a piezoelectric actuator and one end of a cavity unit, FIG. Is a partially enlarged perspective view of the cavity unit, FIG. 5 is an exploded perspective view of the piezoelectric actuator, FIG. 6 is an enlarged sectional view of the ink jet printer head, FIG. 7 is an operation explanatory view, and FIG. FIG.
[0014]
The plate-type piezoelectric actuator 20 shown in FIG. 1 is joined to the cavity unit 10, and a flexible flat cable 40 is overlapped on the upper surface of the piezoelectric actuator 20 for connection with an external device. ing. Then, ink is ejected downward from nozzles opened on the lower surface side of the lowermost cavity unit 10.
[0015]
The cavity unit 10 is configured as shown in FIGS. That is, five thin plates of the nozzle plate 11, two manifold plates 12, the spacer plate 13, and the base plate 14 are laminated.
[0016]
In the embodiment, each of the plates 12, 13, and 14 is made of a 42% nickel alloy steel plate (longitudinal modulus of elasticity: 147 GPa) and has a thickness of about 50 μm to 250 μm, except for the nozzle plate 11 made of a synthetic resin. In the nozzle plate 11, a large number of nozzles 15 for ink ejection having a minute diameter (about 25 μm in the embodiment) are formed at minute intervals. The nozzles 15 are arranged in two rows in a staggered arrangement along the first direction (long side direction) of the nozzle plate 11.
[0017]
As shown in FIGS. 3, 4 and 6, common ink passages 12a and 12b are formed in the two manifold plates 12 on both sides of the rows of the nozzles 15 substantially along the long sides of the manifold plates 12. It is drilled to extend. However, the common ink passage 12b in the lower manifold plate 12 is formed so as to be open only on the upper side of the manifold plate 12. The common ink passages 12a and 12b are sealed by stacking the spacer plates 13 on the two manifold plates 12, and have a structure that functions as a common ink supply passage for a plurality of pressure chambers 16 arranged in a row.
[0018]
As shown in FIGS. 3 and 4, a plurality of pressure chambers 16 are formed in the base plate 14 in two rows in a staggered arrangement along the long side (the first direction) of the base plate 14. . Each pressure chamber 16 is formed in an elongated shape so that its longitudinal direction is orthogonal to the longitudinal direction of the base plate 14.
[0019]
A partition 14a having a width L2 is formed between the pressure chambers 16 arranged in a row, and the width of the pressure chamber 16 in the narrow direction is L1 at the center. In the embodiment, as shown in FIG. 7, L1> L2, and specifically, the thickness of the base plate 14 is set to 50 μm, L2 = 89 μm, and L1 = 250 μm. The thickness of the spacer plate 13 is about 50 μm to 250 μm.
[0020]
The distal end 16a of each pressure chamber 16 is located at a substantially central portion in the short side direction of the base plate 14, and each distal end 16a is formed in the spacer plate 13 and the two manifold plates 12 in the same staggered arrangement. The nozzle plate 11 communicates with the staggered nozzles 15 in the nozzle plate 11 via a small diameter through hole 17 as an ink flow path.
[0021]
On the other hand, the other end portions 16b of the pressure chambers 16 are connected to common ink passages 12a and 12b (common ink chambers) of the two manifold plates 12 through through holes 18 formed in both right and left portions of the spacer plate 13. ). The other end 16b is formed to be concave so as to open downward as shown in FIG. A filter 29 for removing dust in the ink supplied from the ink tank above the supply hole 19a (see FIG. 3) is formed on one end of the uppermost base plate 14. Have been.
[0022]
Thus, the ink flowing into the common ink passages 12a and 12b from the supply holes 19a and 19b formed in one end of the base plate 14 and the spacer plate 13 passes through the through holes 18 from the common ink passage 12a. After being distributed into each of the pressure chambers 16 through the pressure chambers 16, the pressure chambers 16 pass through the through holes 17 to reach the nozzles 15 corresponding to the pressure chambers (FIGS. 3 and 6). reference).
[0023]
On the other hand, in the piezoelectric actuator 20, a plurality of piezoelectric layers and electrode layers are alternately stacked, and the piezoelectric layer is formed of a single piezoelectric sheet having a thickness of about 30 μm made of piezoelectric ceramics. In this embodiment, as shown in FIG. 5, the piezoelectric actuator 20 has a structure in which a plurality of piezoelectric sheets 21 are stacked, and a top sheet 22 is stacked on the top surface thereof. The electrode layer is formed on the upper surface (wide surface) of the piezoelectric sheet as an electrode pattern of a metal film as described later.
[0024]
Of the plurality of piezoelectric sheets 21, the plurality of piezoelectric sheets on the cavity unit 10 side (which is referred to as a lower side) include an active portion provided to be capable of expanding and contracting corresponding to each pressure chamber 16. Construct an active layer. Note that the plurality of piezoelectric sheets on the upper layer side may form a constrained layer including a constrained portion for restricting the active portion from expanding and contracting upward.
[0025]
In the active layer, each electrode layer sandwiched between the piezoelectric layers is alternately positioned in the laminating direction, corresponding to each of the pressure chambers 16, and selectively applied with a voltage. It has a wide shape extending over the plurality of pressure chambers 16 and is an electrode layer of a common electrode 25 connected to a common potential.
[0026]
Specifically, the individual electrodes 24 are formed on the electrode layers on the upper surfaces of the even-numbered piezoelectric sheets 21 counted from the lowermost end of the piezoelectric sheets. Further, a common electrode 25 is formed on an electrode layer on each upper surface of the odd-numbered piezoelectric sheets 2 counted from the lowermost end of the piezoelectric sheets. Each end of the long side of the piezoelectric sheet 21 having the common electrode 25 is connected to the common electrode 25 by a lead portion 25a extending over substantially the entire length near the pair of short sides of the piezoelectric sheet 21. ing.
[0027]
In the piezoelectric sheet 21 on which the common electrode 25 is formed, the individual electrodes 24 are located on the upper surface near the edges of the long sides of the pair where the common electrode 25 is not formed. At the same vertical position (corresponding position), a dummy individual electrode 26 having a width substantially equal to that of the individual electrode 24 and a short length is formed.
[0028]
In addition, on the upper surface of the piezoelectric sheet 21 on which the individual electrodes 24 are formed, a dummy common is located at a position corresponding to the lead-out portion 25a (the same vertical position, near the short edge of the pair of piezoelectric sheets). An electrode 27 is formed.
[0029]
The individual electrode 24, the common electrode 25, the dummy individual electrode 26, and the dummy common electrode 27 described above are screen-printed with a conductive paste made of a silver-palladium alloy on the upper surface of the piezoelectric sheet, so that the individual electrodes 24, the common electrode 25, and the dummy common electrode 27 are respectively formed at predetermined locations. Is formed.
[0030]
On the upper surface of the top sheet 22, surface electrodes 30 and 31 are printed and formed, and the flexible flat cable 40 is overlapped and joined to form various wiring patterns (not shown) in the flexible flat cable 40. It is electrically connected to each surface electrode 30, 31.
[0031]
Except for the lowermost piezoelectric sheet 21, all the other piezoelectric sheets 21 include the surface electrodes 30 and the individual electrodes 24 and the dummy individual electrodes 26 at the corresponding positions (the same vertical position). A through hole 32 is formed so as to communicate. Similarly, the at least one surface electrode 31 (in the embodiment, the surface electrodes 31 at the four corner positions of the uppermost piezoelectric sheet 21) and the lead portion 25 a of the common electrode 25 at the corresponding position (the same vertical position). Also, a through hole 33 is formed so that the dummy common electrode 27 communicates with each other. The individual electrodes 24 of each layer and the surface electrode 30 at a corresponding position are electrically connected to each other through the conductive material filled in the through holes 32 and 33, and the individual electrodes 24 of the respective layers are similarly connected. The first common electrode 25a, the second common electrode 25b, and the surface electrode 31 at a corresponding position are electrically connected.
[0032]
In manufacturing, a through hole is formed in a ceramic green sheet constituting each piezoelectric sheet, and each electrode pattern is formed on the green sheet by screen printing of a conductive paste using a silver-palladium alloy material. At the same time, the conductive material forming the electrode pattern penetrates and fills the through hole. As a result, conduction can be achieved through the through holes on the upper and lower surfaces of the piezoelectric sheet. Then, the green sheets are laminated so that the lower electrode pattern or dummy electrode and the upper layer through hole overlap, are pressed and integrated in the laminating direction, and are baked to form the piezoelectric actuator 20 in a known manner. .
[0033]
As described above, in the piezoelectric layer sandwiched between the individual electrode 24 and the common electrode 25, the common electrode 25 is grounded in a known manner through a conductive material in the through holes 32 and 33, and all the individual electrodes 24 When a positive high voltage for polarization is applied, the regions of the piezoelectric sheet of each layer sandwiched between the electrodes are polarized in the direction from the individual electrodes 24 to the common electrode 25 to become active portions. That is, the second to seventh piezoelectric sheets from the bottom constitute an active layer. Then, when the common electrode 25 is grounded and a positive low voltage for driving is selectively applied to the individual electrodes 24 as is well known, the active portion is elongated and deformed by the piezoelectric longitudinal effect. That is, the piezoelectric layer sandwiched between the individual electrode 24 to which the voltage is applied and the common electrode 25 is distorted in the stacking direction. Then, a large amount of displacement due to the distortion is generated on the pressure chamber 16 side corresponding to each of the individual electrodes 24, the volume of the pressure chamber 16 is reduced, and the ink is ejected from the nozzles 15 in the form of droplets. Printing is performed.
[0034]
During non-ejection, a voltage is applied between all the individual electrodes 24 and the common electrode 25 as described above to reduce the volume of all the pressure chambers 16 so as to correspond to the pressure chambers in which ink is to be ejected. The voltage applied to the individual electrode 24 is selectively released to increase the volume of the pressure chamber 16, and then a voltage is applied again between the individual electrode 24 and the common electrode 25 to reduce the volume of the pressure chamber 16. By returning to the state, ink can be ejected.
[0035]
The operation described below is common to both of the two injection operations.
[0036]
As shown in FIGS. 7 and 8, when the active portion 50 extends in the direction in which the piezoelectric layers are stacked, the volume of the pressure chamber 16-1 at the position facing the active portion 50 decreases. Thereby, the partition wall 14a on the narrow side of the pressure chamber 16-1 is configured such that the side closer to the joint with the piezoelectric actuator 20 falls into the volume of the pressure chamber 16-1, in other words, the pressure chamber 16-1. Are elastically deformed so as to reduce the cross-sectional area (see the solid state in FIGS. 7 and 8). Then, the narrow side surface of the pressure chamber 16-2 in which the active part is adjacent to the driven state and the corresponding active part is in the non-driven state corresponds to the collapse deformation of the partition wall 14a, The side close to the joint with the pressure chamber 16-2 is surrounded by the original cross-sectional area of the pressure chamber 16-2 (shown by a dashed line in FIG. 7, a rectangular area shown by a broken line in FIG. 8, and points A1, C1, C2, and A2 in FIG. 8). (Rectangular area). A triangular area surrounded by points A1, B1, and C1 (or points A2, B2, and C2) in FIG.
[0037]
On the other hand, the spacer plate 13 on the bottom surface of the pressure chamber 16-2, that is, the spacer plate 13 on the side opposite to the side on which the piezoelectric actuator 20 is disposed is bent upward by elasticity so as to reduce the volume of the pressure chamber 16-2. (See the upwardly convex curved area surrounded by points A1, D, A2, and E in FIG. 8). This convex curved region is referred to as a bottom cross-sectional change amount Z2.
[0038]
If the volume of the pressure chamber 16-2 in which the active portion is not driven fluctuates in the decreasing or increasing direction due to such elastic deformation, the pressure in the ink in the pressure chamber 16-2 fluctuates. In particular, the amount of change [Z2 + (2 ×) in the volume of the pressure chamber 16-2 in which the active part located between the two pressure chambers 16-1 and 16-1 corresponding to the active part in the driven state is in the non-driven state. Z1)], there is a problem that the pressure fluctuation becomes large, undesired ink may be ejected, and the print quality is extremely deteriorated.
[0039]
Therefore, in the present invention, when the active portion is selectively driven, the active portion faces the pressure chamber 16-2 corresponding to the active portion which is adjacent to the pressure chamber 16-1 corresponding to the active portion and which is not driven. In other words, the amount of change Z2 in the bottom cross section of the pressure chamber 16-2 due to the deformation of the spacer plate 13 and the amount of change Z1 in the side cross section due to the deformation of the partition 14a due to the driving of the active portion are substantially cancelled. Then, even when the ink is ejected from the adjacent pressure chamber, the thickness of the spacer plate 13 is reduced so that the volume of the pressure chamber 16-2 in which the active portion is not driven is substantially equal to the original state. To set.
[0040]
<Experimental results>
The plate material of the base plate 14 and the spacer plate 13 is the same material of 42% nickel alloy steel plate (longitudinal modulus of elasticity = 147 GPa.), The plate thickness of the base plate 14, that is, the height of the partition 14a is 50 μm, and the thickness of the partition 14a is The width L2 is set to 89 μm. The dimension L1 in the narrow width direction of the pressure chambers 16-1 and 16-2 was set to 250 μm. Further, the longitudinal elastic modulus of the piezoelectric actuator 20 = 68.6 GPa. And
[0041]
With the above conditions being kept constant, the thickness of the spacer plate 13 is changed between 50 μm and 200 μm, and both activities corresponding to the left and right pressure chambers 16-1 and 16-1 sandwiching the pressure chamber 16-2 are performed. FIG. 9A is a table showing the change in the value of the bottom cross-section change amount Z2 and the value of twice the side cross-section change amount Z1 (both right and left sides of the pressure chamber 16-2) when the units are simultaneously driven. FIG. 9B shows a graph. As can be understood from the experimental results, when the thickness of the spacer plate 13 is 100 μm, the change in the cross-sectional area of the pressure chamber 16-2 in which the active portion is not driven is −0.049 (× 10 ^−6). mm ² ).
[0042]
That is, since the change in the bottom cross-sectional change amount Z2 due to the change in the plate thickness of the spacer plate 13 is larger than the change in the side cross-sectional change amount Z1, when the plate thickness of the spacer plate 13 is reduced, the warpage of the spacer plate 13 is caused. , The cross-sectional area of the pressure chamber 16-2 decreased. When the thickness of the spacer plate 13 was increased, the amount of change in the bottom cross section (Z2) was reduced, and the amount of change in the bottom cross section was smaller than the amount of change in the side cross section (Z1).
[0043]
Accordingly, the above-mentioned condition, that is, the ratio of the longitudinal elastic modulus between the spacer plate 13 and the piezoelectric actuator 20 is set to 2: 1, and the thickness of the spacer plate 13 is set to approximately twice the thickness of the base plate 14; The sectional area of the partition wall 14a is set to about one third of the sectional area of the pressure chambers 16-1 and 16-2 in a direction perpendicular to the longitudinal direction, and the thickness of the spacer plate 13 is reduced. In the case of about 100 μm, even if the active portions corresponding to the pressure chambers on both sides are driven, the cross-sectional area of the pressure chamber corresponding to the portion where the active portion is not driven hardly changes from the original value. The ink had almost no pressure fluctuation, and the printing quality was good.
[0044]
From the consideration of the experimental results, the material of the piezoelectric actuator 20, the material of the spacer plate 13, the material and the plate thickness of the base plate 14 for forming the pressure chamber 16, the dimension L1 and the arrangement interval of the pressure chamber 16 in the narrow width direction. Without changing specifications that directly affect the performance of the ink jet printer head, such as (the width L2 of the partition wall 14a), a simple design change that only changes the thickness of the spacer plate 13 that covers one side of the pressure chamber is possible. It was found that the interference (crosstalk) between adjacent pressure chambers during ink ejection was drastically reduced, and that the printing quality could be greatly improved.
[0045]
In the present invention, in addition to the type in which the nozzle is opened in the plate stacking direction of the cavity unit 10, the nozzle is formed in the thickness of the pace plate in a direction perpendicular to the stacking direction, and Needless to say, the present invention can also be applied to a type in which ink is ejected in a direction parallel to the above.
[0046]
[Action and Effect of the Invention]
As described in detail above, the inkjet printer head according to the first aspect of the present invention includes a plurality of nozzles arranged in a row, pressure chambers arranged in a row corresponding to each of the nozzles, A cavity unit formed by stacking a plurality of plates having a flow passage communicating from the chamber to each of the nozzles, and a common ink chamber for storing ink from an ink supply source and then refilling the pressure chamber, In an ink jet printer head that can be selectively driven for each chamber and has a plate-shaped actuator that has an active portion that can expand and contract in the pressure chamber direction and that ejects ink, the base plate has a longitudinal direction. The pressure chambers arranged in parallel and arranged in a row are formed so as to be adjacent to each other with a partition wall interposed therebetween, and are stacked on the opposite side to the actuator with the base plate interposed therebetween. A pressure plate adjacent to the pressure chamber corresponding to the active part and facing the pressure chamber corresponding to the non-driven active part when the active part is selectively driven. The thickness of the spacer plate is set so that the amount of change in the bottom cross-section of the chamber and the amount of change in the side cross-section due to the deformation of the partition wall due to the driving of the active portion are substantially equal.
[0047]
According to such a configuration, the material of the piezoelectric actuator, the material of the spacer plate, the material and the plate thickness of the base plate for forming the pressure chamber, and the narrowness of the partition in the narrow width direction and the arrangement interval of the pressure chamber. Without changing the specifications that directly affect the performance of the ink jet printer head, such as the width dimension, a simple design change that only changes the thickness of the spacer plate that covers one side of the pressure chamber, The remarkable effect that the interference (crosstalk) between the adjacent pressure chambers is drastically reduced and the printing quality can be greatly improved.
[0048]
According to a second aspect of the present invention, in the ink jet printer head according to the first aspect, the base plate and the spacer plate are made of a 42% nickel alloy steel plate, whereby the entire material of the cavity unit 10 is formed. And a cavity unit having a small thickness and a high rigidity can be provided.
[0049]
Further, according to a third aspect of the present invention, in the ink jet printer head according to the first or second aspect, the cavity unit is formed by merely setting the thickness of the spacer plate to approximately twice the thickness of the base plate. It is not necessary to increase the thickness of the other plates in the above, and it is possible to provide a highly rigid cavity unit with a small thickness.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a piezoelectric inkjet printer head according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view of a cavity unit and a piezoelectric actuator.
FIG. 3 is an exploded perspective view of a cavity unit.
FIG. 4 is a partially enlarged perspective view of a cavity unit.
FIG. 5 is a perspective view showing one end of a piezoelectric actuator.
FIG. 6 is a sectional view of the ink jet printer head.
FIG. 7 is an explanatory diagram showing a change in a cross section of a pressure chamber in a narrow width direction.
FIG. 8 is an enlarged cross-sectional view of a main part showing a cross-sectional change of the pressure chamber.
FIG. 9A is a diagram showing a table of experimental results, and FIG. 9B is a diagram showing a graph.
[Explanation of symbols]
Reference Signs List 10 Cavity unit 11 Nozzle plate 12 Manifold plate 13 Spacer plate 14 Base plate 14a Partition wall 15 Nozzle 16 (16-1, 16-2) Pressure chamber 20 Piezoelectric actuator 21 Piezoelectric sheet 24 Individual electrode 25 Common electrode 50 Active part Z1 Side sectional variation Z2 bottom section change

Claims (3)

A plurality of nozzles arranged in a row, pressure chambers arranged in a row corresponding to each nozzle, a flow passage communicating from each pressure chamber to each nozzle, and after storing ink from an ink supply source. A cavity unit formed by laminating a plurality of plates each having a common ink chamber for replenishing the pressure chamber, and an active part that can be selectively driven for each of the pressure chambers and that can expand and contract in the direction of the pressure chamber. In an inkjet printer head having a plate-shaped actuator that has and ejects ink,
In the base plate, the pressure chambers arranged in a row in parallel with each other in the longitudinal direction are formed so as to be adjacent to each other via a partition wall,
Having a spacer plate laminated on the opposite side of the actuator across the base plate,
When the active portion is selectively driven, a bottom cross-sectional change of the pressure chamber due to deformation of the spacer plate adjacent to the pressure chamber corresponding to the active portion and facing the pressure chamber corresponding to the non-driven active portion. Amount, so that the amount of change in the side cross-section due to the deformation of the partition wall accompanying the driving of the active portion is substantially equal,
An ink jet printer head, wherein the thickness of the spacer plate is set. 2. The ink jet printer head according to claim 1, wherein the plate material of the base plate and the spacer plate is a 42% nickel alloy steel plate. 3. The ink jet printer head according to claim 1, wherein the thickness of the spacer plate is set to approximately twice the thickness of the base plate.

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