JP2011148114A - Inkjet head and inkjet apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the cross talk between ink chambers in an inkjet head. <P>SOLUTION: The inkjet head has an ink supply channel with a supply port for supplying the ink from outside, and two or more ink chambers connected with the ink supply channel. The ink chamber has a piezoelectric element which applies a pressure to the ink, and a nozzle for ejecting the ink. The ink jet head further includes a piezoelectric plate to which two or more piezoelectric elements are fixed and which constitutes a top surface of the ink chamber, a nozzle plate in which two or more nozzles are formed and which constitutes a bottom surface of the ink chamber, and partition walls which constitute the side surfaces of the ink chambers and are arranged between the ink chambers. The piezoelectric element is not in contact with the partition wall, and the partition wall is not connected with the piezoelectric plate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an inkjet head and an inkjet apparatus including the inkjet head.

  A drop-on-demand ink jet head is known as an ink jet head that can apply a necessary amount of ink when necessary according to an input signal. In particular, piezoelectric drop-on-demand ink jet heads are being actively developed because they can apply a wide variety of inks with fine control. A piezo-type drop-on-demand ink jet head generally includes an ink supply channel, a plurality of ink chambers connected to the ink supply channel, and a nozzle that applies pressure to the ink filled in the ink chamber. An element.

  In a piezo-type inkjet head, pressure is applied to ink in an ink chamber due to mechanical distortion of the piezo element caused by applying a drive voltage to the piezo element, and ink droplets are ejected from nozzles. Piezo-type ink jet heads can be roughly classified into three types: a shear mode type, a push mode type, and a bend mode type, depending on how the piezoelectric element is distorted. In particular, the bend mode using a piezo element with a laminated structure can generate a strong force at a low voltage, so it can eject highly viscous ink and is expected to be developed for manufacturing electronic devices such as organic EL displays and liquid crystal panels. (For example, refer to Patent Document 1).

  FIG. 1 is a cross-sectional view of an ink jet head described in Patent Document 1. In FIG. As shown in FIG. 1, an inkjet head 1 described in Patent Document 1 includes a plurality of ink chambers 10 having nozzles (not shown), and a piezo element 11 having a stacked structure that applies pressure to the ink in the ink chamber 10. Have Each ink chamber is connected to an ink supply channel (not shown).

  As shown in FIG. 1, the inkjet head 1 includes a lid 13, a partition wall 15, and a substrate 17. The piezo element 11 is fixed to the substrate 17. The lid 13 and the partition wall 15 are composed of one member. The partition wall 15 and the piezo element 11 are in contact with each other, and the partition wall 15 is bonded to the substrate 17.

  In addition, air may be mixed into the ink inside the inkjet head, or the nozzles of the inkjet head may be clogged, making it impossible to discharge ink appropriately. In view of this, a technique for reducing air contamination and nozzle clogging by circulating ink in the inkjet head (supplying ink to the inkjet head from the outside and discharging the ink from the inkjet head) has been proposed (Patent Document 2). reference). In order to circulate the ink in the ink jet head, there are a mode in which only the ink in the ink supply channel is circulated and a mode in which the ink in the ink supply channel and the ink in the ink chamber are circulated together.

Japanese Patent Application Laid-Open No. 07-266559 JP 2008-254196 A

  As described above, in the ink jet head described in Patent Document 1, the piezo element 11 is in contact with the partition wall 15. As described above, when the piezo element is in contact with the partition disposed between the ink chambers, vibration due to mechanical distortion of the piezo element 11 may be transmitted to the adjacent ink chamber 10B through the partition 15. It was. Thus, the fact that the vibration of the piezo element in one ink chamber affects other ink chambers is called crosstalk. When such crosstalk occurs, the amount of ink droplets ejected between the ink chambers becomes unstable, and the ink ejection pitch becomes unstable.

  SUMMARY An advantage of some aspects of the invention is that it provides a piezo-type inkjet head free from crosstalk.

  The present inventor has found that a sufficient pressure can be applied to the ink so that the piezo element can eject ink without separating the piezo element and the partition and connecting the partition and the piezo plate. To complete the present invention.

That is, the first of the present invention relates to the following inkjet head.
[1] An ink supply channel having a supply port for supplying ink from the outside, and two or more ink chambers connected to the ink supply channel, and the ink chamber applies pressure to the ink An inkjet head having a piezo element and a nozzle for ejecting the ink, wherein two or more piezo elements are fixed and a piezo plate constituting the top surface of the two or more ink chambers; The above-mentioned nozzle is formed, and further includes a nozzle plate constituting the bottom surface of the two or more ink chambers, and a partition wall constituting the side surface of the ink chamber and disposed between the ink chambers, The element is not in contact with the partition, and the partition is not connected to the piezo plate.
[2] The ink jet head according to [1], wherein the piezo element is a laminated piezo element.
[3] The interval between the partition walls on the nozzle plate side is narrower than the interval between the partition walls on the piezo plate side. The ink jet head according to [2], wherein the element contacts the partition wall.
[4] The piezo plate has an elastic member for each ink chamber, the piezo element is fixed on the elastic member, and a part of the elastic member is disposed on the partition wall. [1] The inkjet head described in 1.
[5] The ink jet head according to any one of [1] to [4], wherein the ink supply channel has an ink discharge port for discharging ink.
[6] Any one of [1] to [4], further including an ink discharge channel having a discharge port for discharging ink to the outside, wherein the ink discharge channel is connected to two or more ink chambers. An ink jet head according to claim 1.

A second aspect of the present invention relates to the following ink jet apparatus.
[7] An ink jet apparatus comprising the ink jet head according to any one of [1] to [6].

  According to the present invention, crosstalk between ink chambers can be suppressed. Therefore, according to the present invention, an ink jet head capable of stably ejecting ink droplets is provided.

Cross-sectional view of a conventional inkjet head 1 is a perspective view of an inkjet head according to a first embodiment. Sectional drawing of the inkjet head of Embodiment 1 Partial enlarged view of a cross section of the ink jet head of Embodiment 1. Sectional drawing of the inkjet head of Embodiment 1 Sectional drawing of the inkjet head of Embodiment 2. FIG. Partial enlarged view of a cross section of the inkjet head of the second embodiment Sectional drawing of the inkjet head of Embodiment 3 Partial enlarged view of the cross section of the inkjet head of Embodiment 3. Sectional drawing of the inkjet head of Embodiment 3 A perspective view of an inkjet head according to a fourth embodiment. Sectional drawing of the inkjet head of Embodiment 4. FIG. A perspective view of an ink jet head according to a fifth embodiment. Sectional drawing of the inkjet head of Embodiment 5

1. About the inkjet head of the present invention The inkjet head of the present invention is a drop-on-demand type piezoelectric inkjet head having a plurality of ink chambers. The present invention is characterized in that crosstalk between ink chambers is reduced by devising the positional relationship of the constituent members of the inkjet head.

  The inkjet head of the present invention includes an ink supply channel and a plurality of ink chambers connected to the ink supply channel.

  The ink supply channel has at least an ink supply port through which ink is supplied from the outside, and is a channel through which ink supplied to the ink chamber flows. The ink supply channel may have an ink discharge port in addition to the ink supply port (see Embodiment 4, FIG. 11). When the ink supply channel has a discharge port, the discharge port is preferably arranged on the most downstream side of the ink supply channel. By providing the ink discharge port in the ink supply channel, the ink in the ink supply channel can be circulated.

  The ink supply amount supplied to the ink supply channel is not particularly limited, and may be several ml / min or more. The ink supplied to the ink supply channel through the supply port is distributed and provided to each of the plurality of ink chambers.

  The ink chamber is a space for storing ink ejected from the nozzles. The ink supply channel and the ink chamber are connected to each other through an ink communication hole. The maximum number of ink chambers connected to one ink supply channel is usually 1024.

  The ink chamber has a nozzle and a piezo element. The nozzle is a tube that communicates with the outside and has a discharge hole. One ink chamber may have one nozzle or two or more nozzles. The ink in the ink chamber passes through the inside of the nozzle and is discharged to the outside from the discharge hole. The diameter of the discharge hole is not particularly limited, and may be about 10 to 100 μm, for example.

  Piezo elements are actuating devices that convert control signals into actual motion. By applying a voltage to the piezo element, the volume of the piezo element expands and pressure is applied to the ink in the ink chamber. As a result, ink is ejected from the ejection holes of the nozzles.

  The piezo element in the present invention may be a thin film piezo element or a laminated piezo element. Thin film piezos have a fast output response to input but tend to have low output. For this reason, the thin film piezo tends to vary in ejection depending on the ink pressure and viscosity in the ink chamber to be ejected. Therefore, depending on the type of ink, proper ejection may not be possible. On the other hand, the laminated piezo has a slow output response to the input, but it is easy to increase the output. Therefore, the laminated piezo is less affected by the ink pressure in the ink chamber to be ejected, and can realize stable ejection. Therefore, the piezo element of the present invention is preferably a laminated piezo element. The height (length in the stacking direction) of the laminated piezoelectric element is usually 100 to 1000 μm.

  The type of ink stored in the ink chamber is not particularly limited, and is appropriately selected depending on the type of product. For example, when the product is an organic EL panel, an example of ink stored in the ink chamber includes a solution containing an organic light emitting substance such as a light emitting material. In the case of manufacturing a liquid crystal panel, examples of ink include a high-viscosity functional liquid such as a liquid crystal material.

  The ink jet head of the present invention may have an ink discharge channel (see Embodiment 5 and FIG. 13). One ink discharge channel may be provided for one ink supply channel, or a plurality of ink discharge channels may be provided. A plurality of the aforementioned ink chambers are connected to the ink discharge channel along the ink flow. By providing the ink discharge channel connected to the ink chamber, the ink in the ink chamber can be circulated. Thereby, it is possible to prevent ink ejection failure and the like.

  The ink discharge channel has an ink discharge port for discharging ink to the outside, for example, an ink tank of an ink jet apparatus. Ink is supplied to the ink discharge channel from a plurality of ink chambers, and the ink is discharged to the outside through the ink discharge port.

  As described above, the present invention is characterized in that crosstalk between ink chambers is reduced by devising the positional relationship of the constituent members of the inkjet head. Hereinafter, the positional relationship of the constituent members of the ink chamber of the ink jet head of the present invention will be described.

  The components of the inkjet head include a piezo plate that forms the top surface of the ink chamber, a nozzle plate that forms the bottom surface of the ink chamber, and a partition wall that forms the side surface of the ink chamber and is disposed between the ink chambers. It is. Thus, an inkjet head having a plurality of ink chambers is configured by arranging a plurality of partition walls between the piezo plate and the nozzle plate.

  The piezo plate is a plate on which a plurality of piezo elements are fixed. The material of the piezo plate is, for example, ceramic. By making the material of the piezo plate ceramic, the thermal expansion coefficient of the piezo element and the piezo plate can be made the same. Further, the piezo element may be fixed to an elastic member formed on the piezo plate (see Embodiment 3).

  The nozzle plate is a plate on which a plurality of nozzles are formed. The nozzle plate is, for example, a stainless (for example, SUS304 stainless steel) plate having a thickness of 10 to 100 μm.

  The partition walls are arranged between the ink chambers and divide the ink chambers. The material of the partition wall is, for example, stainless steel (for example, SUS304 stainless steel). The partition wall may be rectangular (see Embodiment 1) or tapered (see Embodiment 2). The height of the partition wall may be 5 to 100 μm higher than the height of the piezoelectric element, and is usually 105 to 1100 μm. In the present invention, the partition wall is connected to the nozzle plate. The partition wall may be affixed to the nozzle plate with an adhesive or may be affixed by welding, or may be affixed by thermal diffusion bonding (thermocompression bonding).

  The present invention is characterized in that each piezoelectric element does not contact the partition wall. For this reason, a gap is formed between the piezoelectric element and the partition. The width of the gap between the piezoelectric element and the partition wall is preferably 5 to 100 μm, and more preferably 5 to 20 μm. If the width of the gap between the piezo element and the partition is 5 μm or less, the piezo element may come into contact with the partition when the piezo element expands due to voltage application. On the other hand, when the width of the gap between the piezoelectric element and the partition is 20 μm or more, when pressure is applied to the ink, the ink escapes into the gap between the piezoelectric element and the partition and applies sufficient pressure to the ink. It may not be possible.

  The present invention is further characterized in that the partition wall is not connected to the piezo plate. Here, “not connecting the partition wall and the piezo plate” means that the partition wall and the piezo plate are separate members, and the partition wall and the piezo plate are not joined.

  As described above, in the conventional ink jet head, the partition walls that divide the ink chambers are in contact with the piezo elements (see FIG. 1). For this reason, the vibration of the piezo element is transmitted to the adjacent ink chamber through the partition wall, and crosstalk may occur between the ink chambers. When crosstalk occurs between the ink chambers, the ink ejection pitch becomes unstable, or the amount of ink droplets ejected between the ink chambers becomes unstable.

  On the other hand, in the present invention, the partition walls that separate the ink chambers and the piezo elements are not in contact as described above. For this reason, the vibration of the piezo element is not transmitted to the partition wall, and the crosstalk between the ink chambers is reduced.

  As described above, the present invention is characterized in that the piezo element and the partition wall do not contact each other. However, when the piezo element is a laminated piezo element, the piezo element is provided only when the laminated piezo element becomes high by application of a driving voltage. May contact the partition (see Embodiment 3). In order to bring the laminated piezo element into contact with the partition only when a drive voltage is applied, the interval between the partition walls on the nozzle plate side may be narrower than the interval between the partition walls on the piezoelectric plate side (see FIGS. 7A and 7B). ).

  Furthermore, the present inventor has found that when a piezo plate to which a piezo element is fixed and a partition are connected, vibration of the piezo element is transmitted to the partition through the piezo plate, causing crosstalk. For this reason, in this invention, a partition and a nozzle plate are not connected. By not connecting the partition wall and the nozzle plate in this way, the vibration of the nozzle plate is not transmitted to the partition wall, and crosstalk between the ink chambers can be further reduced.

  Thus, the crosstalk between the ink chambers can be suppressed by separating the piezo element and the partition and not connecting the partition and the nozzle plate. Therefore, according to the present invention, an ink jet head capable of stably ejecting ink droplets is provided.

2. About the manufacturing method of the inkjet head of this invention The inkjet head of this invention mentioned above is manufactured by arbitrary methods, unless the effect of this invention is impaired. Preferred examples of the method for manufacturing an inkjet head of the present invention include 1) a first step of preparing a piezo plate, 2) a second step of laminating a frame on the piezo plate, and 3) a partition wall connected on the frame. And a third step of laminating the nozzle plates.

  1) In the first step, a piezo plate to which a plurality of piezo elements are fixed is prepared. For example, when the piezo element is a laminated piezo element, the plurality of piezo elements are: i) First, a driver is manufactured by laminating a plurality of sheets of lead zirconate titanate (PZT) and a conductive film on a piezo plate. Ii) Then, it may be produced by dividing the drive body. In order to divide the drive body, a dicing apparatus incorporating a rotating blade may be used.

  2) In the second step, a frame is stacked on the piezo plate. Here, the “frame” is a member constituting the outer wall of the ink jet (see FIGS. 2, 3, and 160). The frame may be affixed to the piezo plate with an adhesive or may be affixed by welding, but may be affixed by thermal diffusion bonding (thermocompression bonding).

  3) In the third step, a nozzle plate to which a plurality of partition walls are connected is stacked on the frame. An ink chamber having a bottom surface, a side surface, and a top surface is configured by stacking a nozzle plate having a plurality of partition walls connected on a frame on a piezo plate.

  The partition walls are arranged to be inserted between the piezo elements. The partition wall may be affixed to the nozzle plate by an adhesive or may be affixed by welding, but may be affixed by thermal diffusion bonding (thermocompression bonding). The nozzle plate may be attached to the frame with an adhesive or may be attached by welding, but may be attached by thermal diffusion bonding (thermocompression bonding). On the other hand, as described above, the partition is not connected to the nozzle plate.

3. About the inkjet device of the present invention The inkjet device of the present invention is characterized by comprising the above-described inkjet head, but otherwise has members of known inkjet devices as appropriate. For example, it has a member for fixing the ink jet head, a moving stage for placing and moving an object to which ink is applied, and the like.

  The ink jet device includes an ink circulation device when the ink of the ink jet head is circulated. The ink is circulated by a driving pressure of a pump or the like, but is preferably circulated through a circulation tank so that the supply pressure is constant. The ink jet device may circulate ink of the ink jet head constantly during operation of the device; it may circulate intermittently.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to these embodiments.

(Embodiment 1)
FIG. 2 is a perspective view of the inkjet head 100 according to the first embodiment of the present invention. As shown in FIG. 2, the inkjet head 100 includes an ink supply channel 101 and an ink chamber 110. The ink supply channel 101 is connected to the ink tank 105 via the ink supply port 103.

  FIG. 3A is a cross-sectional view taken along line A of the inkjet head 100 shown in FIG. FIG. 3B is a cross-sectional view taken along line B of the inkjet head 100 shown in FIG. 3C is a cross-sectional view taken along line C of the inkjet head 100 shown in FIG.

  As shown in FIGS. 3A to 3C, the ink chamber 110 includes a nozzle 111 and a laminated piezo element (hereinafter, also simply referred to as “piezo element”) 113. The ink chamber 110 contains ink to be ejected from the ejection hole 112 of the nozzle 111. Further, as shown in FIG. 3B, the ink chamber 110 is connected to the ink supply channel 101 through the ink communication hole 107.

  3A and 3B, the inkjet head 100 includes a nozzle plate 150 that forms the bottom surface of the ink chamber 110, a partition wall 130 that forms the side surface of the ink chamber 110, and a top surface of the ink chamber 110. It has a piezo plate 140 that constitutes and a frame 160 that constitutes the outer wall of the inkjet head 100.

  The width X of the partition wall 130 shown in FIG. 3A is 50 to 200 μm, and the height Z is 105 to 1100 μm. Moreover, the length Y of the partition 130 shown by FIG. 3C is 100-2000 micrometers.

  The piezo element 113 is fixed to a piezo plate 140 constituting the top surface of the ink chamber as shown in FIG. 3B.

  FIG. 4 is an enlarged view of a region surrounded by a square M in FIG. 3A. As shown in FIG. 4, the piezo element 113 is not in contact with the partition wall 130. Further, the partition wall 130 is not connected to the piezo plate 140. The width D of the gap between the piezo element 113 and the partition wall 130 is 5 to 100 μm. The width D ′ of the gap between the partition wall 130 and the piezo plate 140 may be 0 to 20 μm.

  Next, the operation of the inkjet head 100 according to Embodiment 1 will be described with reference to FIGS. 5A and 5B. 5A and 5B are enlarged views of the ink chamber 110 shown in FIG. 3A, and the right side views of FIGS. 5A and 5B are the ink chamber 110 shown in FIG. 3B.

  First, ink is supplied from the ink tank 105 to the ink supply channel 101. The ink supplied to the ink supply channel 101 is supplied to each ink chamber 110 through the ink communication hole 107 (see FIG. 5A).

  Next, a driving voltage is applied to the piezo element 113. Thereby, the height of the piezo element 113 is increased and the capacity of the ink chamber 110 is reduced (FIG. 5B). As a result, pressure is applied to the ink in the ink chamber 110. When pressure is applied to the ink, the ink is pushed out in the direction of the arrow in FIG. 5B. As a result, ink droplets are ejected from the ejection holes 112.

  As described above, in the present embodiment, the piezo element 113 and the partition wall 130 are separated from each other. For this reason, even when the height of the piezo element 113 is increased as shown in FIG. 5B, vibration of the piezo element 113 is not transmitted to the partition wall 130. Further, since the partition wall 130 and the piezo plate 140 are not connected, the vibration of the piezo element 113 is not transmitted to the partition wall through the piezo plate. For this reason, crosstalk between the ink chambers 110 can be reduced.

  On the other hand, since the partition wall 130 and the piezo plate 140 may be separated from each other, it is conceivable that the pressurized ink passes through the gap between the partition wall 130 and the piezo plate 140 and enters the adjacent ink chamber. However, since the gap between the partition wall 130 and the piezo plate 140 is sufficiently narrow, the pressurized ink escapes only to the nozzle 111 or the ink communication hole 107 which is wider than the gap between the partition wall 130 and the piezo plate 140 and is adjacent. It does not flow into the ink chamber.

  Thereafter, when a voltage opposite to the drive voltage is applied to the piezo element 113, the height of the piezo element is reduced and the capacity of the ink chamber 110 is reduced. As a result, the ink flows again from the ink supply channel 101 into the ink chamber 110.

  Thus, according to the ink jet head of the present embodiment, crosstalk between the ink chambers is suppressed, so that ink can be ejected stably.

(Embodiment 2)
In the second embodiment, a mode in which the laminated piezo element contacts the partition only when a driving voltage is applied will be described.

  FIG. 6 is a cross-sectional view of the inkjet head 200 according to the second embodiment. The inkjet head 200 is the same as the inkjet head 100 of Embodiment 1 except that the shape of the partition is different. The same components as those of the ink jet head 100 of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 6, the inkjet head 200 according to the second embodiment includes a partition wall 131 that forms the side surface of the ink chamber 110. As shown in FIG. 6, the interval W between the partition walls 131 on the nozzle plate 150 side is narrower than the interval W ′ between the partition walls 131 on the piezoelectric plate 140 side. The partition wall 131 has a tapered shape, and the width of the partition wall 131 decreases from the nozzle plate 150 toward the piezo plate 140.

  Thus, by making the interval W narrower than the interval W ′, the piezo element 113 can be brought into contact with the partition wall 131 only when the drive voltage is applied. In addition, by bringing the piezo element 113 into contact with the partition wall 131 only when the drive voltage is applied, it is possible to apply a stronger pressure to the ink in the ink chamber 110. Hereinafter, the relationship between bringing the piezo element 113 into contact with the partition wall 131 when applying the drive voltage and increasing the pressure applied to the ink will be described.

  FIG. 7A is an enlarged view of a region surrounded by a square M in FIG. FIG. 7B shows a state in which a driving voltage is applied to the piezo element 113 shown in FIG. 7A and the height of the piezo element 113 is increased.

  As shown in FIG. 7B, when the height of the piezo element 113 is increased by the application of the driving voltage, the upper surface of the piezo element 113 comes into contact with the partition wall 131. For this reason, in the ink chamber 110, the ink in the region 110 a surrounded by the upper surface of the piezo element 113 and the partition wall 131 whose height has increased cannot escape between the piezo element 113 and the partition wall 131. Thereby, a stronger pressure can be applied to the ink in the region 110a.

  Thus, according to the present embodiment, ink can be pushed out with a strong force. For this reason, even when ink with high viscosity is stored in the ink chamber, the ink can be pushed out from the ejection holes.

(Embodiment 3)
In Embodiment 3, a mode in which the piezo plate has an elastic member and the piezo element is fixed on the elastic member will be described.

  FIG. 8 is a cross-sectional view of the inkjet head 300 according to the third embodiment. The inkjet head 300 is the same as the inkjet head 100 of Embodiment 1 except that the shape of the piezo plate is different. The same components as those of the ink jet head 100 of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 8, in the inkjet head 300 according to the third embodiment, the piezo plate 141 has an elastic member 143 for each ink chamber 110. The elastic member 143 is, for example, conductive rubber. The elastic member 143 is arranged not only on the ink chamber 110 but also on the partition wall 130. The piezo element 113 is fixed on the elastic member 143.

  In this way, by fixing the piezo element 113 on the elastic member 143 partially disposed on the partition wall 130, it becomes possible to apply a stronger pressure to the ink in the ink chamber 110. Hereinafter, the relationship between fixing the piezo element 113 on the elastic member 143 and increasing the pressure applied to the ink will be described.

  FIG. 9A is an enlarged view of a region surrounded by a square M in FIG. FIG. 9B shows a state in which a driving voltage is applied to the piezo element 113 shown in FIG. 9A and the height of the piezo element 113 is increased.

  As shown in FIG. 9B, when the height of the piezo element 113 increases, the elastic member 143 follows the movement of the piezo 113, and the elastic member 143 rises to the ink chamber 110 side. As a result, the elastic member 143 contacts the partition wall 130 and closes the gap between the partition wall 130 and the piezo plate 141. For this reason, the pressure applied to the ink chamber 110 cannot escape to the gap between the partition wall 130 and the piezo plate 141. Thereby, a strong pressure can be applied to the ink in the ink chamber 110.

  Thus, according to the present embodiment, ink can be pushed out with a strong force. For this reason, even when ink with high viscosity is stored in the ink chamber, the ink can be pushed out from the ejection holes.

  8 and 9 show examples of the conductive rubber or the like in which the elastic member is arranged on the piezo plate. As shown in FIG. 10, the region of the piezo plate 142 is thinned until elasticity occurs. 144 may be an elastic member.

(Embodiment 4)
In the fourth embodiment, a mode in which ink in the ink supply channel circulates will be described.

  FIG. 11 is a perspective view of the inkjet head 400 according to the fourth embodiment. The ink jet head 400 of the fourth embodiment is the same as the ink jet head 100 of the first embodiment except that the ink supply channel 101 has the ink discharge port 104. Constituent elements that are the same as those of the inkjet head 100 of the first embodiment are given the same reference numerals, and descriptions thereof are omitted.

  As shown in FIG. 11, the ink supply channel 101 of the inkjet head 400 has an ink discharge port 104. FIG. 12 is a cross-sectional view taken along line A of the inkjet head 400 shown in FIG. As shown in FIG. 12, by providing an ink discharge port 104 in the ink supply flow channel 101, ink can flow in the ink supply flow channel 101 from the supply port 103 toward the discharge port 104. The ink in the path 101 can be circulated. As a result, it is possible to prevent stagnation of ink in the ink supply channel 101 and mixing of air. Further, by circulating the ink in the ink supply channel 101, the temperature of the ink in the ink supply channel 101 can be made uniform, and the temperature of the ink supplied to each ink chamber 110 can be made uniform.

(Embodiment 5)
In the fifth embodiment, an ink jet head having an ink discharge channel will be described.

  FIG. 13 is a perspective view of an inkjet head 500 according to the fifth embodiment. The inkjet head 500 according to the fifth embodiment is the same as the inkjet head 100 according to the first embodiment except that the inkjet head 500 includes the ink discharge channel 102. Constituent elements that are the same as those of the inkjet head 100 of the first embodiment are given the same reference numerals, and descriptions thereof are omitted.

  As shown in FIG. 13, the inkjet head 500 has an ink discharge channel 102. Each ink chamber 110 is connected to the ink discharge channel 102. Further, the ink discharge channel 102 has an ink discharge port 104. FIG. 14A is a cross-sectional view taken along line A of the inkjet head 500 shown in FIG. 14B is a cross-sectional view taken along line B of the inkjet head 500 shown in FIG.

  As shown in FIGS. 14A and 14B, by providing the ink discharge channel 102 in the inkjet head 500, ink can flow from the ink supply channel 101 through the ink chamber 110 to the ink discharge channel 102, The ink in the ink chamber 110 can be circulated. Thereby, it is possible to suppress stagnation and air of ink in the ink chamber 110, and it becomes possible to discharge ink stably.

  In the ink jet head of the present invention, the crosstalk between the ink chambers is small. Therefore, the ink jet head of the present invention can uniformly apply ink to an object to be coated. Therefore, for example, it is preferably used as an inkjet head for coating and forming an organic light emitting material in the production of an organic EL display panel.

100, 200, 300, 400, 500 Inkjet head 101 Ink supply channel 102 Ink discharge channel 103 Ink supply port 104 Ink discharge port 105 Ink tank 107 Ink communication hole 110 Ink chamber 111 Nozzle 112 Ejection hole 113 Laminated piezo element 130, 131 Partition 140, 141, 142 Piezo plate 143, 144 Elastic member 150 Nozzle plate 160 Frame

Claims (7)

An ink supply channel having a supply port for supplying ink from the outside;
An ink jet head having two or more ink chambers connected to the ink supply channel, the ink chamber having a piezo element that applies pressure to the ink and a nozzle for ejecting the ink. And
Two or more piezoelectric elements are fixed, and two or more piezoelectric plates constituting the top surface of the ink chamber;
Two or more nozzles are formed, and two or more nozzle plates constituting the bottom surface of the ink chamber;
A side wall of the ink chamber, and a partition wall disposed between the ink chambers; and
The piezo element does not contact the partition,
The partition wall is an inkjet head not connected to the piezo plate.   The inkjet head according to claim 1, wherein the piezo element is a laminated piezo element. The interval between the partition walls on the nozzle plate side is narrower than the interval between the partition walls on the piezoelectric plate side,
The inkjet head according to claim 2, wherein when the driving voltage is applied to the piezo element and the laminated piezo element is raised, the laminated piezo element contacts the partition wall. The piezo plate has an elastic member for each ink chamber,
The inkjet head according to claim 1, wherein the piezoelectric element is fixed on the elastic member, and a part of the elastic member is disposed on the partition wall.   The ink jet head according to claim 1, wherein the ink supply channel has an ink discharge port for discharging ink.   The inkjet head according to claim 1, further comprising an ink discharge channel having a discharge port for discharging ink to the outside, wherein the ink discharge channel is connected to two or more ink chambers.   An ink jet apparatus comprising the ink jet head according to claim 1.

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