JP4379128B2 - Inkjet head - Google Patents

Description

The present invention relates to an ink jet heads for ejecting liquid.

  Ink jet printers that spray ink droplets directly onto recording paper are widely used. Ink jet heads used in ink jet printers include a thermal method and a piezoelectric method, but the piezoelectric method is superior in terms of ink droplet ejection stability and flexibility in ink selection.

  The piezoelectric inkjet head has a structure as shown in FIG. In the ink jet head of FIG. 10, the pressure plate 106 is formed by joining the nozzle plate 101 to one end of the wall member 103 and joining the diaphragm 105 to the other end of the wall member 103. Here, a nozzle 102 is formed in the center of the nozzle plate 101, and an ink supply port 107 is formed in the wall member 103.

  The pressure generating means 110 is a piezoelectric element and bends the diaphragm 105 by displacement due to electric distortion. Due to this bending, the volume of the pressure chamber 106 filled with ink is reduced, and ink is ejected from the nozzle 102. After the ink is ejected, the application of voltage to the pressure generating means 110 is stopped, and the volume of the pressure chamber 106 is restored, whereby the ink is refilled into the pressure chamber 106 from the ink supply port 107.

  On the other hand, in recent years, development has been carried out in which inkjet technology is applied to surface mounting of ultrafine wiring, and further small droplet ejection and high viscosity ink ejection are required. In order to realize small droplet discharge and high viscosity ink discharge, it is necessary to apply a high pressure to the ink in the pressure chamber 106. For this purpose, it is necessary to increase the force generated by the pressure generating means 110. However, since the ink is compressible, not only does the force generated by the pressure generating unit 110 increase, but the amount of deflection of the diaphragm 105 does not increase as the volume of the pressure chamber 106 increases, It is not possible to generate a large pressure on the surface. That is, in order to realize small droplet discharge and high viscosity ink discharge, the force transmitted from the diaphragm 105 to the ink in the pressure chamber 106 is increased, and the volume change rate (volume change amount / original volume) of the pressure chamber 106 is increased. It is important to increase the volume.

  However, in the configuration of FIG. 10, the force transmitted from the vibration plate 105 to the ink in the pressure chamber 106 is obtained by subtracting the force necessary to bend the vibration plate 105 from the force applied from the pressure generating means 110 to the vibration plate 105. Power. For this reason, the force that deflects the diaphragm 105 is lost, and it is difficult to efficiently transmit the force to the ink.

  Furthermore, in the configuration of FIG. 10, when the volume change rate of the pressure chamber 106 is to be increased, it is necessary to increase the curvature of the deflection of the diaphragm 105, and a large stress is applied to the connection portion between the diaphragm 105 and the wall member 103. Is generated, and the connection portion is easily damaged.

A method for solving this problem is proposed in Patent Document 1, and the contents thereof will be described with reference to FIG. The difference from FIG. 10 is that the structure has the elastic member 104 in a part of the wall member 103 and the thickness of the diaphragm 105 is increased to make it difficult to bend. In the configuration of FIG. 11, the main volume change of the pressure chamber 106 is caused not by the bending of the diaphragm 105 but by the compression of the elastic member 104. As a result, a force for bending the diaphragm 105 is not necessary, and the force applied to the diaphragm 105 by the pressure generating means 110 is efficiently transmitted to the ink in the pressure chamber 106. Further, even when the volume change rate of the pressure chamber 106 is increased, the vibration of the diaphragm 105 is small, so that there is no concern about the damage of the diaphragm 105.
JP-A-8-156250

  However, in order to achieve further small droplet ejection and high viscosity ink ejection, it is necessary to further increase the force applied to the diaphragm 105 by the pressure generating means 110, but this is difficult to achieve with the configuration of FIG. The reason will be described below.

  As a method for increasing the force applied to the diaphragm 105 in the configuration of FIG. 1. a method for increasing the voltage applied to the pressure generating means 110; 2. a method of increasing the cross-sectional area by forming the pressure generating means 110 in a laminated structure as shown in FIG. A method of increasing the number of stacked layers by considering the pressure generating means 110 as a stacked structure as shown in FIG. However, in the method 1 described above, since there is an upper limit to the voltage applied to the pressure generating means 110, the force generated in the pressure generating means 110 cannot be increased freely. In the above methods 2 and 3, in any of the lamination methods, the generated force does not increase and only the displacement increases, which is not effective.

  The present invention solves the above-described conventional problems, and increases the force generated in the pressure generating means and efficiently transmits the generated force to the ink in the pressure chamber without damaging the diaphragm. It is an object of the present invention to provide an ink jet head that can perform further small droplet discharge and high viscosity ink discharge.

In order to solve the above-described conventional problems, an ink jet head according to the present invention includes a wall member having a nozzle, a diaphragm pressed against the wall member via an elastic member, a wall member, the elastic member, and the diaphragm. A pressure chamber that stores ink and communicates with the nozzle, and a pressure generating member that moves the diaphragm relative to the wall member to change the volume of the pressure chamber, and is perpendicular to the displacement direction of the diaphragm. With regard to a simple cross section, the cross-sectional area of the pressure generating member is made larger than the cross-sectional area of the pressure chamber, and an ink supply port that communicates with the pressure chamber is provided in the diaphragm .

In this configuration, the main volume change of the pressure chamber is not caused by the vibration of the diaphragm but by the compression of the elastic member. As a result, the force that bends the diaphragm is minimized, and the force applied by the pressure generating means to the diaphragm is efficiently transmitted to the ink in the pressure chamber. Further, since the bending of the diaphragm is minimized, there is no need to worry about damage to the diaphragm. Further, regarding the cross section perpendicular to the displacement direction of the diaphragm, the cross-sectional area of the pressure generating member is made larger than the cross-sectional area of the pressure chamber, so that the generated force is increased without increasing the relative displacement of the diaphragm with respect to the wall member. Can do. Accordingly, it is possible to provide an ink jet head capable of increasing the force generated in the pressure generating means and efficiently transmitting the generated force to the ink in the pressure chamber without damaging the diaphragm. Droplet ejection and high viscosity ink ejection are possible. In addition, since the ink supply port is provided on the diaphragm, the flow path resistance of the ink supply port can be easily set to a desired value, and the flow of ink can be made smooth when the volume of the pressure chamber is small. . Accordingly, it is possible to provide an ink jet head that has high ejection performance and is less likely to cause non-ejection.

  In the inkjet head, the diaphragm includes a convex portion corresponding to the shape of the diaphragm-side opening of the wall member on the surface in contact with the elastic member.

  In this configuration, the convex portion increases the contact pressure between the elastic member around the opening and the diaphragm, and improves the sealing performance of the pressure chamber. Therefore, it is possible to provide an ink jet head in which ink leakage hardly occurs.

  In the ink jet head, the convex portion corresponding to the shape of the opening on the diaphragm side of the wall member has a closed curve shape including the opening.

  Also in this configuration, the contact pressure between the elastic member around the opening and the diaphragm is increased, and the sealing performance of the pressure chamber is improved. Therefore, it is possible to provide an ink jet head in which ink leakage hardly occurs.

  Further, in the inkjet head, the wall member is provided with a convex portion around the opening on the diaphragm side of the wall member, and has a closed curve shape including the opening.

  Also in this configuration, the contact pressure between the elastic member around the opening and the wall member is increased, and the sealing performance of the pressure chamber is improved. Therefore, it is possible to provide an ink jet head in which ink leakage hardly occurs.

  In the ink jet head, both the nozzle and the pressure chamber have an axisymmetric shape, and their axes are on substantially the same axis.

  In this configuration, since the nozzle axis and the pressure chamber axis are substantially on the same axis, the ink flow is very smooth and the ink filling property is good. In addition, since it is axially symmetric, it is possible to provide an ink jet head in which the straightness of the ink is not disturbed by the influence of residual vibration.

  In the ink jet head, the nozzle also serves as a pressure chamber.

  In this configuration, since the nozzle also serves as the pressure chamber, the volume of the portion to which pressure is applied by the pressure generating member is very small. Therefore, the absolute value of the ink compression amount can be reduced, and the influence of compression can be reduced. Therefore, with this configuration, it is possible to provide an inkjet head that facilitates small droplet ejection and high viscosity ink ejection. In this configuration, since the nozzle also serves as the pressure chamber, the wall member is thin, and the wall member is easily deformed by the pressure applied by the pressure generating member. Therefore, for the purpose of eliminating the deformation of the wall member, it is preferable to provide a reinforcing member on at least one surface of the wall member.

  In the ink jet head, the elastic member uses an O-ring.

  In this configuration, an O-ring having good sealing performance and load resistance is used as the elastic member. Therefore, it is possible to provide a highly reliable inkjet head that is unlikely to cause ink leakage or the like. Note that a commercially available product can be used for the O-ring, which can be cheaper than a configuration in which an elastic member is formed on the wall member.

  The ink jet head includes a preliminary liquid chamber structure having a preliminary liquid chamber communicating with the ink supply port at an upper portion of the ink supply port, and the pressure generating member is joined to the preliminary liquid chamber structure. is there.

  With this configuration, the ink supply port and the auxiliary liquid chamber can be smoothly communicated with each other.

  In the ink jet head, a preliminary liquid chamber structure including a preliminary liquid chamber communicating with the ink supply port is provided above the ink supply port, and the pressure generating member is directly joined to the diaphragm.

  Also with this configuration, the ink supply port and the preliminary liquid chamber can be smoothly communicated.

  In the ink jet head, the preliminary liquid chamber structure is connected to the diaphragm via an elastic member.

  In this configuration, when the diaphragm is vibrated by the pressure generating means, it is not necessary to operate the preliminary liquid chamber structure and the diaphragm as one body, and the preliminary liquid chamber structure and the diaphragm can be operated separately. It is. Therefore, it is possible to efficiently use the force generated in the pressure generating means for operating the diaphragm. Thereby, an inkjet head with high ejection performance can be provided.

  In the ink jet head, the preliminary liquid chamber structure and the pressure generating member are pressed against the diaphragm by the same pressing member.

  With this configuration, since only one means for pressurizing the preliminary liquid chamber structure and the pressure generating means to the diaphragm is required, the cost and size of the inkjet head can be reduced.

  Moreover, the inkjet head manufacturing method by this invention has the process of forming an elastic member in the single side | surface of a wall member in the said inkjet head, and the process of forming a pressure chamber from the surface in which the elastic member of the wall member was formed. It is.

  With this manufacturing method, an elastic member can be accurately provided at the edge of the opening of the pressure chamber, and an ink jet head that is less likely to cause ink leakage can be manufactured.

  According to the present invention, it is possible to provide an ink jet head capable of increasing the force generated in the pressure generating means and efficiently transmitting the generated force to the ink in the pressure chamber without damaging the diaphragm. Thus, further small droplet discharge and high viscosity ink discharge are possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a schematic configuration of the ink jet head according to the first embodiment.

The nozzle plate 1 is a stainless steel plate having a thickness of 50 μm, and a nozzle 2 is formed at a substantially central portion of the plate. Nozzle 2 has an outlet side diameter of φ10 μm and an inlet side diameter of φφ
It has a taper shape of 50 μm.

  The wall member 3 is made of stainless steel, and a cylindrical hole of φ200 μm is formed in a substantially central portion. The outlet side surface of the wall member 3 is joined to the inlet side surface of the nozzle plate 1.

  The elastic member 4 is a rubber material such as silicone rubber or fluorine rubber, and has a thickness of about 10 μm. The elastic member 4 is first formed on the surface of the wall member 3 having no holes by spin coating, casting or the like. Thereafter, through holes are formed in the elastic member 4 and the wall member 3 from the elastic member 4 side in the same process by laser processing, drilling, or the like.

  The diaphragm 5 is made of stainless steel and is pressed against the elastic member 4 by being pressed by the preliminary liquid chamber structure 8. The diaphragm 5 has a convex portion at a portion facing the pressure chamber on the elastic member 4 side, and the pressing force of the elastic member is concentrated on the convex portion. Thus, by increasing the contact pressure between the diaphragm 5 and the elastic member 4, the sealing performance of the pressure chamber 6 is improved. Further, the diaphragm 5 includes an ink supply port 7 that communicates between the pressure chamber 6 and the auxiliary liquid chamber 9.

  The pressure chamber 6 is formed by the nozzle plate 1, the wall member 3, the elastic member 4, and the diaphragm 5.

  The preliminary liquid chamber structure 8 is bonded to the vibration plate 5 so as to cover the ink supply port 7, and the preliminary liquid chamber 9 is formed by the vibration plate 5. The preliminary liquid chamber 9 communicates with an ink supply unit (not shown).

The pressure generating means 10 is a piezoelectric element, and an electrode (not shown) is formed so that an electric field is applied. Regarding the cross section perpendicular to the displacement direction of the diaphragm, the cross sectional area of the pressure generating means is made larger than the cross sectional area of the pressure chamber. Specifically, the pressure generating means has a cross-sectional area of 1 mm ² and a thickness of 30 μm. Further, a voltage of 30 V is applied to the pressure generating means 10. The pressurizing member 11 displaces the diaphragm 5 to the wall member 3 side via the preliminary liquid chamber structure 8 by suppressing the pressure generating means 10 from moving upward in FIG. The pressurizing member 11 is connected to the preliminary liquid chamber structure 8 via the pressure generating means 10.

  Next, the operation will be described. First, the ink is filled in an ink supply section (not shown) → the reserve liquid chamber 9 → the ink supply port 7 → the pressure chamber 6 → the nozzle 2. Next, when a voltage is applied to the pressure generating means 10, the pressure generating means 10 expands in the vertical direction of FIG. Here, since the upward movement in FIG. 1 is suppressed by the pressure member 11, the pressure generation means 10 cannot expand to the pressure member 11 side. Therefore, the preliminary liquid chamber structure 8 and the diaphragm 5 move to the wall member 3 side while compressing the elastic member 4. By this movement, the volume of the pressure chamber 6 is reduced, pressure is applied to the ink held in the pressure chamber 6, and the ink is ejected from the nozzle 2. Then, when the application of the electric field to the pressure generating means 10 is released, the expanded pressure generating means 10 is restored and the volume of the pressure chamber 6 is also restored. At this time, ink is replenished from the ink supply port 7 to the pressure chamber 6, and preparation for the next ink discharge is completed.

  Ink was actually ejected, and the amount and ejection speed of the droplets were measured. In the ink jet field where the viscosity of the ink is 50 cP, even when a very high viscosity ink was used, the discharge amount was 0.3 picoliter and the discharge speed was 8 m / s. From this result, it was found that it is possible to discharge a considerably small droplet as compared with a droplet discharged from an inkjet head used in a general printer (several picoliters). The discharge speed was defined as the average flying speed at a distance of 1 mm from the nozzle.

  According to such a configuration, the main volume change of the pressure chamber 6 is not caused by the bending of the diaphragm 5 but by the compression of the elastic member 4. Thereby, the force applied to the diaphragm 5 by the pressure generating means 10 is efficiently transmitted to the ink in the pressure chamber 6. Further, since the bending of the diaphragm 5 is minimized, there is no fear of the diaphragm 5 being damaged. Further, regarding the cross section perpendicular to the displacement direction of the diaphragm, the cross-sectional area of the pressure generating means is larger than the cross-sectional area of the pressure chamber, so that the force generated without increasing the relative displacement of the diaphragm 5 with respect to the wall member 3 is increased. can do. Therefore, it is possible to provide an ink jet head that can efficiently transmit the generated force to the ink in the pressure chamber 6 without increasing the force generated in the pressure generating means 10 and damaging the diaphragm. , Small droplet ejection and high viscosity ink ejection are possible.

  Further, according to such a configuration, the diaphragm 5 includes the convex portion corresponding to the shape of the opening of the wall member 3 on the surface that contacts the elastic member 4. Therefore, the contact pressure between the elastic member 4 and the diaphragm 5 around the opening is increased, the sealing performance of the pressure chamber 6 can be improved, and ink leakage hardly occurs.

  Moreover, according to this structure, both the nozzle 2 and the pressure chamber 6 are axisymmetric shapes, and those axes are on substantially the same axis. As a result, the ink flow becomes very smooth, which makes it possible to provide an ink jet head that has good ink filling properties and is less likely to disturb the straightness of the ink due to the influence of residual vibration.

  On the other hand, regarding the cross section perpendicular to the displacement direction of the diaphragm, the ink supply port 7 is arranged in a direction perpendicular to the displacement direction of the diaphragm 5 because the cross sectional area of the pressure generating means is larger than the cross sectional area of the pressure chamber. In this case, the length of the ink supply port 7 becomes long, and the flow path resistance increases.

  However, according to this configuration, since the ink supply port 7 is provided in the diaphragm 5, the flow path resistance of the ink supply port 7 can be easily set to a desired value, and the volume of the pressure chamber 6 is small. The ink flow can be made smooth. Accordingly, it is possible to provide an ink jet head that has high ejection performance and is less likely to cause ejection defects.

  In addition, according to this configuration, the preliminary liquid chamber structure 8 including the preliminary liquid chamber 9 communicating with the ink supply port 7 is disposed above the ink supply port 7, and the pressure is supplied via the preliminary liquid chamber structure 8. The diaphragm 5 is moved by the generating member 10, and the ink supply port 7 and the preliminary liquid chamber 9 can be smoothly communicated. Accordingly, it is possible to provide an ink jet head that easily removes bubbles and the like mixed during ink filling and is less likely to cause ejection failure.

  Further, according to the manufacturing method of the present embodiment, the elastic member 4 is formed on one surface of the wall member 3, and then the through hole is formed in the wall member 3 and the elastic member 4 in the same process, whereby the pressure chamber The elastic member 4 can be accurately provided at the edge portion of the opening 6, and an ink jet head in which ink leakage hardly occurs can be manufactured.

  In the present embodiment, the diaphragm 5 includes a convex portion corresponding to the shape of the inlet opening of the wall member 3, and this convex portion is an opening of the wall member 3 as shown in FIG. The shape of the closed curve may be included. In FIG. 2, the illustration of the configuration above the diaphragm 5 is omitted to facilitate understanding of the drawing. Also in this configuration, the contact pressure between the elastic member 4 and the diaphragm 5 around the opening of the wall member 3 can be increased, and the sealing performance of the pressure chamber 6 can be improved.

  In the present embodiment, a single layer piezoelectric element is used for the pressure generating means 10, but a piezoelectric element having a laminated structure may be used. Furthermore, as the pressure generating means 10, a so-called electrostatic actuator using electrostatic force or a magnetostrictive element using magnetic force may be used.

  In this embodiment, the pressure member 11 is bonded to the wall member 3, but it may be bonded to the nozzle plate 1.

  Note that the nozzle plate 1 may be omitted by forming the nozzle 2 on the wall member 3.

(Embodiment 2)
As shown in FIG. 3, the inkjet head according to the second embodiment is provided with a convex portion around the opening of the wall member 3 on the diaphragm 5 side. In addition, in order to make an understanding of a figure easy, illustration of the structure above the diaphragm 5 is abbreviate | omitted. The difference from the first embodiment is that the projection around the opening is provided not on the diaphragm 5 but on the wall member 3 and that the elastic member 4 is formed on the diaphragm 5 side.

  The formation method of a convex part is demonstrated using FIG. First, a convex part is formed in the approximate center part of the wall member 3 in which the pressure chamber 6 is not formed by etching or the like. Thereafter, the pressure chamber 6 is formed in the inner region of the convex portion by electric discharge machining, laser processing, or the like, and at the same time, the convex portion is formed around the opening of the pressure chamber 6.

  Also in the second embodiment, as in the first embodiment, the contact pressure between the elastic member 4 around the opening and the wall member 3 can be increased, and the sealing performance of the pressure chamber 6 can be improved. It is possible to provide an ink-jet head in which the occurrence of the ink is difficult.

  Note that the nozzle plate 1 may be omitted by forming the nozzle 2 on the wall member 3.

(Embodiment 3)
As shown in FIG. 5, in the ink jet head according to the third embodiment, the nozzle plate 1 and the wall member 3 are formed from the same member, and the nozzle 2 also serves as the pressure chamber 6. In addition, in order to make an understanding of a figure easy, illustration of the structure above the diaphragm 5 is abbreviate | omitted.

  A method for forming the elastic member 4 will be described. First, the elastic member 4 is formed in a substantially central portion of the wall member 3 having no hole by spin coating, casting or the like. Thereafter, the nozzle 2 that also serves as a pressure chamber is formed from the elastic member 4 side by laser processing, drilling, or the like.

  In this configuration, since the nozzle 2 also serves as a pressure chamber, the volume of the portion to which pressure is applied by the pressure generating means 10 becomes very small. Therefore, the absolute value of the ink compression amount can be reduced, and the influence of compression can be reduced. In addition, when discharging high-viscosity ink, it is necessary to increase the pressure applied to the pressure chamber, thereby increasing the influence of ink compression. In this case as well, the volume of the pressure chamber should be as small as possible. . Therefore, with this configuration, it is possible to provide an inkjet head that facilitates small droplet ejection and high viscosity ink ejection.

  Further, according to the present manufacturing method, the elastic member 4 can be accurately provided at the edge portion of the opening of the nozzle 2, and an ink jet head in which ink leakage hardly occurs can be manufactured.

  In the third embodiment, since the nozzle 2 also serves as a pressure chamber, the wall member 3 is thin, and the wall member is easily deformed by the pressure applied by the pressure generating member. Therefore, as shown in FIG. 6, in order to eliminate the deformation of the wall member 3, it is preferable to provide the reinforcing member 12 on the surface opposite to the pressure generating means.

(Embodiment 4)
As shown in FIG. 7, the ink jet head in the fourth embodiment uses an O-ring as the elastic member 4. In addition, in order to make an understanding of a figure easy, illustration of the structure above the diaphragm 5 is abbreviate | omitted. The difference from the first embodiment is that an O-ring is used as the elastic member 4 and a step for holding the O-ring is provided on the wall member 3.

  The O-ring has good sealing properties against liquids and gases, and load resistance, and further has excellent solvent resistance if a material is selected. Moreover, it is not necessary to form the elastic member 4 by using the O-ring.

  Therefore, by using an O-ring as the elastic member 4, it is possible to provide a highly reliable ink jet head in which ink leakage or the like hardly occurs.

(Embodiment 5)
As shown in FIG. 8, the ink jet head according to the fifth embodiment includes a preliminary liquid chamber structure 8 including a preliminary liquid chamber 9 above the ink supply port 7, and the pressure generating means 10 is connected to the diaphragm 5. It is joined. The difference from the first embodiment is that the pressure generating means 10 is directly connected to the diaphragm 5 without using the preliminary liquid chamber structure 8.

  According to the fifth embodiment, as in the first embodiment, the ink supply port 7 and the auxiliary liquid chamber 9 can be smoothly communicated with each other. Accordingly, it is possible to provide an ink jet head that easily removes bubbles and the like that are generated during ink filling and that is less likely to cause ejection failure.

(Embodiment 6)
As shown in FIG. 9, the inkjet head according to the sixth embodiment is different from the fifth embodiment in that the preliminary liquid chamber structure 8 is connected to the diaphragm 5 via the elastic body 13 and the pressurizing member 11. Thus, the pressure generating means 10 and the preliminary liquid chamber structure 9 are simultaneously pressed against the diaphragm 5.

  In this configuration, when the vibration plate 5 is vibrated by the pressure generating means 10, it is not necessary to operate the preliminary liquid chamber structure 8 integrally with the vibration plate 5, so that the substantial mass is smaller than that of the fifth embodiment. Is driven by the pressure generating means 10. Thereby, the force generated by the pressure generating means 10 can be efficiently transmitted to the ink in the pressure chamber 6. Thereby, an inkjet head with high ejection performance can be provided.

  Further, since only one pressurizing member 11 for pressurizing the preliminary liquid chamber structure 8 and the pressure generating means 10 to the diaphragm 5 is required, the cost and size of the ink jet head can be reduced.

  The ink jet head according to the present invention can eject high viscosity droplets and small droplets. Therefore, the inkjet head according to the present invention not only ejects ink onto recording paper to record characters and images, but also, for example, forms wiring patterns by ejecting various metal inks and ejects color filter materials. It can also be applied to industrial applications such as color filter formation by, discharge of various materials for EL (electroluminescence) emission, and discharge of various materials for organic TFT creation.

1 is a schematic cross-sectional view of an inkjet head according to Embodiment 1 of the present invention. Schematic configuration diagram of an ink jet head having another configuration according to Embodiment 1 of the present invention. Schematic configuration diagram of an inkjet head according to Embodiment 2 of the present invention. The figure which shows the formation method of the inkjet head in FIG. Schematic configuration diagram of an inkjet head according to Embodiment 3 of the present invention. Schematic configuration diagram of ink jet head according to Embodiment 3 of the present invention (with reinforcing member) Schematic configuration diagram of an inkjet head according to Embodiment 4 of the present invention. Schematic sectional view of an ink jet head according to Embodiment 5 of the present invention. Schematic configuration diagram of an inkjet head according to Embodiment 6 of the present invention. Schematic configuration diagram of a conventional inkjet head Schematic configuration diagram of a conventional inkjet head Schematic configuration diagram of a conventional inkjet head

DESCRIPTION OF SYMBOLS 1 Nozzle plate 2 Nozzle 3 Wall member 4 Elastic member 5 Vibration plate 6 Pressure chamber 7 Ink supply port 8 Preliminary liquid chamber structure 9 Preliminary liquid chamber 10 Pressure generating means 11 Pressure member 12 Reinforcing member 13 Elastic body

Claims (12)

A wall member having a nozzle;
A diaphragm pressed against the wall member via an elastic member;
A pressure chamber formed of the wall member, the elastic member and the diaphragm, storing ink and communicating with the nozzle;
A pressure generating member that moves the diaphragm relative to the wall member and changes a volume of the pressure chamber;
Regarding the cross section perpendicular to the displacement direction of the diaphragm, the cross sectional area of the pressure generating member is larger than the cross sectional area of the pressure chamber,
An ink jet head according to claim 1, wherein the diaphragm is provided with an ink supply port communicating with the pressure chamber . 2. The inkjet head according to claim 1, wherein the diaphragm includes a convex portion corresponding to the shape of the diaphragm side opening of the wall member on a surface that contacts the elastic member. The inkjet head according to claim 2, wherein the convex portion has a closed curve shape including the opening. The wall member is
The inkjet head according to claim 1, wherein the inkjet head has a convex curve around an opening on the diaphragm side and has a closed curve shape including the opening. 5. The inkjet head according to claim 1, wherein both the nozzle and the pressure chamber have an axisymmetric shape, and their axes are on substantially the same axis. . The ink jet head according to claim 1, wherein the nozzle also serves as a pressure chamber. The inkjet head according to claim 1, wherein the wall member is provided with a reinforcing member on a surface opposite to the pressure generating unit. The inkjet head according to claim 1, wherein the elastic member is an O-ring. Wherein the ink supply port upper comprises a preliminary liquid chamber structure with a preliminary liquid chamber communicating with the ink supply port, and said pressure generating member is characterized in that it is joined to the preliminary liquid chamber structure The inkjet head according to claim 1 . Claim 1 wherein the ink supply port upper comprises a preliminary liquid chamber structure with a preliminary liquid chamber communicating with the ink supply port, and the pressure generating member, characterized in that it is directly bonded to the diaphragm The inkjet head described in 1. The inkjet head according to claim 10 , wherein the preliminary liquid chamber structure is connected to a diaphragm via an elastic body. The inkjet head according to claim 11 , wherein the preliminary liquid chamber structure and the pressure generating member are pressed against the diaphragm by the same pressing member.

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