JP2003112422A - Ink jet recording head, vibrator unit and method of manufacturing vibrator unit - Google Patents

Abstract

(57) [Problem] To prevent a variation in the amount of ink ejected due to a variation in a displacement amount of a piezoelectric vibrator. A piezoelectric vibrator operating in a longitudinal vibration mode.
In a plurality of vibrator units 8 each having one end fixed to a fixed substrate 27 at a predetermined pitch,
The amount of displacement is adjusted by fixing the elastic member 28 to the piezoelectric vibrator 9 in the vibration region of the piezoelectric vibrator 9. By making the displacements of the plurality of piezoelectric vibrators 9 the same, it is possible to prevent a variation in the ejection of the ink amount in one row.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head for recording images and characters on recording paper by ejecting ink droplets from nozzle openings by expanding and contracting a piezoelectric vibrator in a longitudinal vibration mode.

[0002]

2. Description of the Related Art A part of a pressure generating chamber communicating with a nozzle for ejecting ink droplets is composed of a vibrating plate, and the vibrating plate is deformed by a piezoelectric vibrator to pressurize the ink in the pressure generating chamber to eject ink from the nozzle. An inkjet recording head that ejects droplets has been put into practical use using a piezoelectric vibrator of a longitudinal vibration mode that expands and contracts in the axial direction.

Among the ink jet type recording heads, a recording head using a piezoelectric vibrator of a longitudinal vibration mode which can be driven at high speed has a nozzle plate having a nozzle opening, a pressure generating chamber communicating with the reservoir and a reservoir. A flow path unit is formed by laminating a flow path forming plate and an elastic plate, and is configured to be driven by a vibrator unit in which one end is fixed at a fixed pitch and a piezoelectric vibrator that expands and contracts in the axial direction is fixed to a fixed substrate. There is.

In such an ink jet recording head, a nozzle array in which a plurality of nozzle openings are arranged is constructed by one vibrator unit. The displacements of the piezoelectric vibrators used in the nozzles have variations, and if they are not aligned, the amount of ink discharged from the nozzles will be different, causing uneven color.

[0005]

In order to solve such a problem, measures have been taken to suppress variations in displacement amount by changing the voltage applied to the piezoelectric vibrator of each nozzle. In the method of applying different drive signals to the nozzles, it is necessary to prepare a drive signal generation circuit for each nozzle, which leads to an increase in cost. The present invention has been made in view of such a problem, and its object is to
It is an object of the present invention to provide an inkjet recording head that can make the displacement amount of the piezoelectric vibrator of each nozzle uniform with respect to one drive signal.

[0006]

In order to solve such a problem, according to the present invention, a nozzle plate having a nozzle opening, a flow path forming plate for forming a pressure generating chamber and a reservoir, and an elastic plate are provided. And a vibrator unit having a plurality of piezoelectric vibrators operating in a longitudinal vibration mode, one end of which is fixed to a fixed substrate at a predetermined pitch. An ink jet type recording head for ejecting ink droplets by pressurizing the pressure generating chamber by abutting the tip end face of the elastic plate, wherein elastically deformable members are fixed to respective vibration regions of the piezoelectric vibrator. The present invention provides an ink jet type recording head.

By having a plurality of rows of the vibrator units, different colors can be arranged for each nozzle row.

In a vibrator unit configured by fixing one end of a plurality of piezoelectric vibrators operating in a longitudinal vibration mode to a fixed substrate at a predetermined pitch, at least one of the piezoelectric vibrators is provided with an elastic member. The vibrator unit is characterized in that it is fixed in the vibration region of the vibrator.

It is characterized in that the elastic member is attached to one side or both sides of the vibration region of the piezoelectric vibrator, thereby expanding the design range.

For each piezoelectric vibrator, the range in which the elastic member is attached to the vibration area of the piezoelectric vibrator is different, the thickness of the elastic member is different, and the elastic members having different elastic moduli are the piezoelectric vibrations. It is characterized in that an arbitrary displacement can be set for each of the piezoelectric vibrators by being attached to the vibration region of the child.

The piezoelectric vibrator is characterized in that it is used in a longitudinal vibration mode capable of high-speed driving because it is constructed by alternately stacking piezoelectric materials and internal electrodes.

A step of measuring displacement of the piezoelectric vibrator in a vibrator unit constituted by fixing one end of a plurality of piezoelectric vibrators operating in a longitudinal vibration mode to a fixed substrate at a predetermined pitch, and displacement data thereof. And a step of fixing an elastic member to the selected piezoelectric vibrator in the vibration region of the piezoelectric vibrator, thereby accurately grasping the suppression amount of the piezoelectric vibrator whose displacement is desired to be suppressed. The present invention provides a method of manufacturing a vibrator unit that can be used.

It is characterized in that the elastic member is formed by applying a thermosetting or ultraviolet curable liquid polymer material to the piezoelectric vibrator and curing it.

An ink jet type liquid coating device is used as a method for coating the polymer material.

[0015]

[Function] It is possible to suppress variations in the displacement of the piezoelectric vibrator within one nozzle row in the ink jet recording head, and to make the amount of ink ejected from each nozzle uniform.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described below with reference to illustrated embodiments. 1 and 2 show an embodiment of an ink jet recording head of the present invention, in which a flow path unit 1 communicates with a nozzle plate 3 in which nozzle openings 2 are formed at a constant pitch, and the nozzle openings 2. Pressure generating chamber 4, a flow path forming substrate 7 having a reservoir 6 that supplies ink to the pressure generating chamber 4 through the ink supply port 5, and the pressure generating chamber by contacting the tips of the piezoelectric vibrators 9 of the vibrator unit 8. The elastic plate 10 for expanding and contracting the volume 4 is integrally laminated.

The flow path unit 1 is formed on the opening surface 12 of a holder 11 formed by injection molding of a polymer material, and the vibration unit 8 is an FPC for transmitting a drive signal from the outside.
(Flexible cable), TCP (tape carrier package), TAB, or other elastically deformable ribbon-shaped cable 13, and then accommodated in the accommodating chamber 14, and the contact surface with each holder 11 is bonded by an adhesive. A frame body 15 which is fixed and also serves as a shield material is inserted on the nozzle plate side and is integrated in the recording head. In this embodiment,
It consists of 6 nozzle rows so that 6 colors of ink can be used. A total of 6 transducer units are installed in each row.

FIGS. 3A and 3B show the vibrator unit 8
FIG. 3 shows an embodiment of the present invention in which a plurality of piezoelectric vibrators 9 are fixed to a fixed substrate 27 so as to match the arrangement pitch of the pressure generating chambers 4 and ink is provided at both ends of the piezoelectric vibrators 9 in the row direction. So-called dummy piezoelectric vibrators 9 ', 9'that do not participate in the ejection of droplets are fixed and configured. In these piezoelectric vibrators 9 and 9 ', an electrode 21 serving as one pole and an electrode 22 serving as the other pole are laminated in a sandwich form with a piezoelectric material 23 interposed therebetween, and one electrode 21 is provided on the free end side. In addition, the other electrode 22 is exposed at the tip on the fixed end side and is connected to the segment electrode 24 and the common electrode 25 at each end face.

In this embodiment, when the elastic member 28 is adhered only to the piezoelectric vibrator 9 whose displacement is desired to be suppressed, the displacement is reduced due to the constraint of the elastic member 28 as shown in FIG. The amount of decrease in displacement of the piezoelectric vibrator 9 is determined by the adhesive area, thickness and elastic modulus of the elastic member 28. By changing the thickness of the elastic member 28, the displacement of the plurality of piezoelectric vibrators 9 can be controlled. In this way, the displacement of the piezoelectric vibrator 9 having a large displacement can be suppressed. Further, in this method, the elastic member 2
Since the amount of displacement suppression is changed by changing the thickness of No. 8, the adhesion area does not change and the adhesion positions can be unified. Further, the elastic member 28 is used for each piezoelectric vibrator 9
By preparing members having different elastic moduli depending on the rank, the shapes of the elastic members 28 can be made uniform, and the design can be facilitated. Further, by attaching the elastic member 28 to one side of the piezoelectric vibrator 9, the manufacturing process can be simplified.

By bonding the elastic member 28 to each piezoelectric vibrator 9 and suppressing the displacement amount of the piezoelectric vibrator 9 having a large displacement, it is possible to manufacture a head in which the displacement of each piezoelectric vibrator 9 can be aligned. it can. When the same drive signal is applied by using this head, it is possible to equalize the ink ejection amount of each nozzle by obtaining the same displacement.

From the above, it is possible to obtain high-quality printing quality by making the ink ejection amount uniform.

FIGS. 5A and 5B show another embodiment of the present invention. In this embodiment, an elastic member 28 having a different range is bonded to the vibration area of the piezoelectric vibrator 9. This controls the amount of displacement suppression. As an implementation method, a liquid polymer is applied to the piezoelectric vibrator 9, and then heat is applied to cure the polymer, whereby the elastic member 28 is formed. An ultraviolet curable material can also be used as the polymer. For coating the polymer, there is a method of preparing a member having a hole in the coating region and coating the hole with the polymer.

FIG. 6 shows a manufacturing method according to an embodiment of the present invention. In this embodiment, the displacement of the piezoelectric vibrator 9 is measured using a laser Doppler microvibration measuring machine 101. These piezoelectric vibrators 9 are, for example, ranks 1 and 1 with displacements of + 0% to 1%, based on the smallest piezoelectric vibrator 9.
The ranks are classified from the displacements measured by the displacement data processing device 102, such as rank 2 of% to 2%, rank 3 of 2% to 3%, and so on. According to these ranks, the piezoelectric vibrator 9 that suppresses displacement is selected and the polymer application range is determined. The polymer coating range is not coated when the piezoelectric vibrator 9 has a rank of 1. If the rank is 2, the displacement of the piezoelectric vibrator 9 is reduced by 1%, and if the rank is 3, the displacement of the piezoelectric vibrator 9 is reduced by 2%. The displacement of the child 9 can be controlled. In this way, the displacement of the piezoelectric vibrator 9 having a large displacement can be suppressed. The coating range is sent to the inkjet liquid coating device 103, and is coated on the piezoelectric vibrator from the inkjet head 104. As described above, by using the ink jet type liquid coating device, accurate coating can be performed without waste. After that, the polymer is cured to become the elastic member 28. The displacement of the piezoelectric vibrator 9 of the vibrator unit 8 to which the elastic member 28 is attached can be set between 0% and + 1%, and the variation in the displacement of each piezoelectric vibrator 9 can be suppressed.

FIG. 7 shows another embodiment of the present invention. In this embodiment, elastic members 28 are attached to both sides of the piezoelectric vibrator 9. When the elastic member 28 is attached to one side, the side of the piezoelectric vibrator 9 to which the elastic member 28 is attached is constrained and the displacement is reduced. In addition, since the side without the elastic member 28 is less likely to be restrained, the displacement is biased.
As shown in, the piezoelectric vibrator 9 oscillates in a cycle of longitudinal vibration fa and flexural vibration fb. On the other hand, when the elastic members 28 are attached to both sides of the piezoelectric vibrator 9, since the displacement is not biased, the flexural vibration fb does not oscillate as shown in FIG. 8 and the residual vibration can be reduced. it can.

[0025]

As described above, in the present invention, a nozzle plate having a plurality of nozzle openings formed therein, a flow path forming plate forming a plurality of pressure generating chambers and a reservoir, and an elastic plate are laminated. In an ink jet recording head composed of a formed flow path unit and a vibrator unit configured by fixing one end of a plurality of piezoelectric vibrators operating in a longitudinal vibration mode to a fixed substrate at a predetermined pitch, a piezoelectric element having a large displacement Since the elastic member is fixed to the vibration region of the piezoelectric vibrator on the vibrator, the displacement can be suppressed by the elastic member, and the displacement can be matched with the piezoelectric vibrator having a small displacement. As a result, the displacement of each piezoelectric vibrator becomes equal to a single drive signal, and the amount of ink ejected from the nozzles can be made uniform, enabling high-quality printing.

[Brief description of drawings]

FIG. 1 is an assembled perspective view showing an embodiment of an ink jet recording head of the present invention.

FIG. 2 is a view showing a cross-sectional structure of the same device.

3A and 3B are a perspective view and a cross-sectional view, respectively, showing an embodiment of a vibrator unit.

FIG. 4 is a displacement characteristic diagram showing a difference depending on the presence or absence of an elastic member.

FIG. 5 is a cross-sectional view showing an example of a vibrator unit.

FIG. 6 is a diagram illustrating a method of manufacturing a vibrator unit using an inkjet liquid coating device.

FIG. 7 is a cross-sectional view showing an example of a vibrator unit.

FIG. 8 is a displacement characteristic diagram showing a difference when elastic members are attached to one side and both sides.

[Explanation of symbols]

1 flow path unit 8 transducer unit 9 Piezoelectric vibrator 11 holder 13 cables 27 Fixed board 28 Elastic member 101 Laser Doppler Micro Vibration Measuring Machine 102 Displacement data processing device 103 Ink jet type liquid coating device 104 inkjet head

Claims (14)

[Claims] 1. A nozzle plate having a plurality of nozzle openings, a flow path forming plate forming a plurality of pressure generating chambers and a reservoir, and a flow path unit formed by laminating elastic plates, and a vertical vibration. A piezoelectric unit which has a plurality of piezoelectric vibrators operating in a mode and which is fixed at one end to a fixed substrate at a predetermined pitch. An inkjet recording head for pressurizing a generation chamber to eject ink droplets, comprising: a vibrator unit in which an elastic member is fixed to a vibration region of the piezoelectric vibrator in each of at least one of the piezoelectric vibrators. An inkjet recording head characterized by: 2. The ink jet recording head according to claim 1, wherein the vibrator unit has a plurality of rows. 3. A vibrator unit constituted by fixing a plurality of piezoelectric vibrators operating in a longitudinal vibration mode at one end to a fixed substrate at a predetermined pitch, wherein at least one of the piezoelectric vibrators has an elastic member. A vibrator unit, wherein the vibrator unit is fixed to a vibration region of the piezoelectric vibrator. 4. The vibrator unit according to claim 3, wherein the elastic member is attached to one side of a vibration region of the piezoelectric vibrator. 5. The vibrator unit according to claim 3, wherein the elastic members are attached to both sides of a vibration region of the piezoelectric vibrator. 6. The vibrator unit according to claim 3, wherein a range in which the elastic member is attached to a vibration region of the piezoelectric vibrator is different for each of the piezoelectric vibrators. 7. The vibrator unit according to claim 3, wherein the thickness of the elastic member is different for each of the piezoelectric vibrators. 8. The vibrator unit according to claim 3, wherein the elastic member having a different elastic modulus for each of the piezoelectric vibrators is attached to a vibration region of the piezoelectric vibrator. 9. The vibrator unit according to claim 3, wherein the piezoelectric vibrator is configured by alternately stacking piezoelectric materials and internal electrodes. 10. A method of manufacturing a vibrator unit comprising a plurality of piezoelectric vibrators operating in a longitudinal vibration mode, one end of which is fixed to a fixed substrate at a predetermined pitch, and displacement of the piezoelectric vibrator is measured. And a step of performing selection based on the displacement data thereof, and a step of fixing an elastic member to the selected piezoelectric vibrator in a vibration region of the piezoelectric vibrator, a method of manufacturing a vibrator unit. . 11. The method of manufacturing a vibrator unit according to claim 10, wherein the elastic member is formed by applying a liquid-state polymer material to the piezoelectric vibrator and curing the same. . 12. The method according to claim 10, wherein a thermosetting material is used as the polymer material. 13. The method of manufacturing a vibrator unit according to claim 10, wherein an ultraviolet curable material is used as the polymer material. 14. The method of manufacturing a vibrator unit according to claim 10, wherein an ink jet type liquid applying device is used as a method of applying the polymer material.