JP2002127410A - Driving method for ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving method for ink jet head in which ink drops are ejected in various states through low voltage driving by controlling the displacement of a diaphragm variously using a plain driving waveform. SOLUTION: An ink jet head has a diaphragm divided into discrete electrodes being applied with a drive voltage of first voltage waveform using an identical reference signal as a trigger, and applies a drive voltage of second voltage waveform, having a polarity different from that of the first voltage waveform and a specified phase lag behind the first voltage waveform, to the diaphragm. Consequently, the diaphragm is displaced according to the overlapped voltage waveforms and, although the first and second voltage waveforms have plain drive voltage waveforms, intricate displacement of the diaphragm can be controlled by combining first and second voltage waveforms appropriately. Since the displacement amount and the displacement rate of the diaphragm can be controlled optimally to an image being formed, image quality can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving an ink jet head, and more particularly, to controlling a displacement of a diaphragm with a simple driving waveform in various manners to drive ink droplets in various states while performing low voltage driving. The present invention relates to a method of driving an ink jet head that discharges ink in a liquid jet head.

[0002]

2. Description of the Related Art An ink jet recording apparatus does not require processes such as development and fixing, and can perform recording in a non-contact manner. Therefore, noise during recording is extremely low, and high-speed printing is possible. It has many advantages such as a high degree of freedom of ink and the ability to use inexpensive plain paper.
Among ink jet recording apparatuses, a so-called ink-on-demand type ink jet recording apparatus that discharges ink droplets only when recording is necessary does not require collection of ink droplets unnecessary for recording and maintenance is performed. Because of its simplicity, small size, and low cost, it has attracted attention.

As such an ink-on-demand type ink jet head, for example, Japanese Patent Publication No.
As described in Japanese Patent No. 1734, a device using a piezoelectric element as a driving means, and as described in Japanese Patent Publication No. 61-59911, a pressure generated by heating ink to generate bubbles. As a driving unit, there is a so-called electrostatic type in which a diaphragm is vibrated by using an electrostatic force to discharge ink, as described in Japanese Patent Application Laid-Open No. Hei 5-50601.

The electrostatic type ink jet head is disclosed in, for example, US Pat. No. 4,520,375, which comprises a capacitor mainly composed of two capacitor plates facing each other at an interval by an insulating means, and a reservoir for containing ink. One of the capacitor plates forms a thin diaphragm made of, for example, silicon semiconductor, and by applying a time-varying voltage to the capacitor, the diaphragm generates mechanical vibration and responds to the movement of the diaphragm. do it,
A liquid ejecting apparatus that ejects ink from a nozzle is disclosed.

[0005] This electrostatic type ink jet head has:
This is very effective as a method for easily processing a large number of nozzles / liquid chambers / actuators for ejecting a large number of inks. However, an electrostatic ink jet head, for example, has a relatively small electrostatic force, a large applied voltage, and a large vibration, compared to a piezoelectric method using PZT (lead zirconate titanate) as an actuator. There is a problem that it is difficult to obtain a high-speed displacement, a problem that it is difficult to selectively control the displacement state of the diaphragm, and a problem that it is difficult to control ejection of ink droplets in a plurality of different states.

Further, in the electrostatic ink jet head, after a pulse driving voltage is applied between the diaphragm and the individual electrodes, electric charges remain on the dielectric between the diaphragm and the individual electrodes, and the residual electric charges are generated. There is a problem that the relative displacement between the diaphragm and the individual electrodes is reduced by the electric field generated, and the image quality of the formed image is deteriorated.

Therefore, conventionally, an actuator including a nozzle, an ink flow path communicating with the nozzle, a vibration plate provided in a part of the flow path, and an electrode provided to face the vibration plate is provided. In the driving method of a printing apparatus that deforms the diaphragm, ejects ink droplets from the nozzles and performs recording, during normal recording, a first voltage that deforms the diaphragm is applied, At a predetermined time, in order to stabilize the displacement amount of the diaphragm, a second voltage having a different polarity from the first voltage and having a magnitude equal to or greater than a voltage value at which the diaphragm contacts the electrode is applied. A method of driving a printing apparatus characterized by the following is proposed (Japanese Patent Laid-Open No. 7-2147).
No. 75).

That is, in the method of driving the printing apparatus, the electric pulse in the direction opposite to the forward electric pulse and in which the diaphragm abuts on the individual electrode is connected to the diaphragm just before the forward electric pulse is applied. By applying a voltage between the electrodes, the residual polarization is eliminated to improve the printing quality.

[0009]

However, in such a method of driving an ink jet head described in Japanese Patent Application Laid-Open No. Hei 7-214775, the individual electrodes are driven in a direction opposite to the forward electric pulse and in the direction of the vibration plate. Immediately before the application of the forward electric pulse, an electric pulse that is applied between the diaphragm and the electrode is applied to eliminate the residual polarization, so that the residual polarization can be eliminated. Cannot be changed in various ways to improve the image quality. In order to improve the image quality, there is a need for improvement and a problem that the driving voltage is increased.

Therefore, according to the present invention, the vibration plate provided in a part of each of the plurality of liquid chambers to which the ink is supplied from the supply liquid chamber through the ink flow path and the vibration plate provided with a predetermined A first driving voltage of a predetermined first voltage waveform having a predetermined first voltage is applied to the individual electrodes disposed opposite to each other with a gap therebetween, and the diaphragm is Applies a second drive voltage having a predetermined second voltage waveform having a predetermined second voltage, and deforms the diaphragm with electrostatic force generated by the first drive voltage and the second drive voltage When a pressure is generated in the liquid chamber and the ink in the liquid chamber is ejected from the nozzle, the first drive voltage and the second drive voltage are made to have different polarities of their voltage waveforms, and the diaphragm The first drive is performed by applying the voltage within a predetermined synchronization period of the drive period. The diaphragm is displaced in a state corresponding to the voltage waveform in which the first voltage waveform of the voltage and the second voltage waveform of the second drive voltage are superimposed, and the displacement of the diaphragm is complicatedly controlled with a simple voltage waveform. It is an object of the present invention to provide a method of driving an ink-jet head that can change the ink discharge state in various ways to improve image quality, and reduce a power supply voltage value while securing a substantial applied voltage.

According to a second aspect of the present invention, there is provided a vibration plate provided in a part of each of a plurality of liquid chambers to which ink is supplied from a supply liquid chamber through an ink flow path, and a predetermined gap formed between the vibration plates. In this case, one of the individual electrodes disposed to face each other is used as a common electrode, and the individual electrode is provided with a first drive voltage having a predetermined first voltage waveform having a predetermined first voltage. Applying a second drive voltage having a predetermined second voltage waveform having a predetermined second voltage to the diaphragm to generate an electrostatic force generated by the first drive voltage and the second drive voltage When the diaphragm is deformed to generate pressure in the liquid chamber and cause the ink in the liquid chamber to be ejected from the nozzles, the first drive voltage and the second drive voltage are used if the polarities of their voltage waveforms are different from each other. At the same time as applying it within a predetermined synchronization period of the diaphragm driving period. In addition, while at least one of the first drive voltage and the second drive voltage is always applied as long as the nozzle is in the recording area at the time of recording, the diaphragm does not become an individual electrode, and A voltage waveform obtained by superimposing a first voltage waveform of a first drive voltage and a second voltage waveform of a second drive voltage in a simple and inexpensive configuration by simplifying a switching process for applying a voltage. The diaphragm is displaced in a state corresponding to the above, and the displacement of the diaphragm is complicatedly controlled with a simple voltage waveform to change the ink discharge state in various ways, thereby improving the image quality and securing a substantial applied voltage. It is still another object of the present invention to provide an inexpensive and simple method of driving an ink-jet head that can reduce a power supply voltage value.

According to a third aspect of the present invention, the first drive voltage and the second drive voltage are applied to the individual electrodes corresponding to the nozzles required to discharge ink among the plurality of individual electrodes and the plurality of diaphragms. And the diaphragm are individually selected and applied, thereby displacing the diaphragm with a plurality of different displacement amounts and displacement speeds in accordance with a combination of the first voltage waveform and the second voltage waveform to form dots. It is an object of the present invention to provide a method of driving an ink jet head that can further improve the image quality by multiplying the values.

According to a fourth aspect of the present invention, the first drive voltage and the second drive voltage having the first voltage waveform and the second voltage waveform having mutually opposite polarities are synchronized with each other, and simultaneously, the individual electrode By applying to the diaphragm, the rise / fall time of the effective pulse is prevented from becoming long, and the diaphragm is displaced at high speed to print at high speed even when multi-nozzles and high density are used. It is an object of the present invention to provide a method for driving an ink-jet head capable of performing processing.

According to a fifth aspect of the present invention, the first voltage waveform and the second voltage waveform have opposite polarities, and the absolute value of the first voltage and the absolute value of the second voltage are the same. Accordingly, an object of the present invention is to provide a method of driving an ink jet head that can generate a first voltage waveform and a second voltage waveform with a simple configuration and can improve image quality with an inexpensive and simple configuration. I have.

According to a sixth aspect of the present invention, there is provided an ink for forming one dot, wherein at least one of the first voltage waveform and the second voltage waveform is a voltage waveform composed of a plurality of pulse groups. A plurality of ink droplets corresponding to the number of pulses, and by controlling the number of pulses, the dot formation is multi-valued, thereby providing a method of driving an inkjet head that can further improve image quality. The purpose is.

According to a seventh aspect of the present invention, the first voltage waveform and the second voltage waveform have mutually opposite polarities, and the polarities thereof are alternately changed. It is an object of the present invention to provide a method of driving an ink jet head capable of appropriately removing residual charges remaining between diaphragms, appropriately displacing the diaphragm, and further improving image quality.

According to the present invention, the first voltage waveform and the second voltage waveform have the same absolute value of the first voltage and the absolute value of the second voltage of the same polarity. By doing
The first voltage waveform and the second voltage waveform are generated with a simple configuration, and the residual charge remaining between the individual electrodes and the diaphragm is appropriately removed to optimize the displacement of the diaphragm. Accordingly, it is an object of the present invention to provide a method of driving an ink jet head which can further improve the image quality.

According to a ninth aspect of the present invention, the first voltage waveform and the second voltage waveform are the same waveform, have mutually different polarities and different phases, so that the first voltage waveform and the second voltage waveform are different from each other. The second voltage waveform is generated with a simple configuration, and the residual charge remaining between the individual electrodes and the diaphragm is appropriately removed, the displacement of the diaphragm is optimized, and the image quality is further improved with a cheap and simple configuration. It is an object of the present invention to provide a method of driving an inkjet head that can be improved.

According to a tenth aspect of the present invention, the first drive voltage and the second drive voltage having the same voltage as the first voltage waveform and opposite polarities are synchronized with each other. In addition, by applying to the individual electrodes and the diaphragm at the same time, the rise / fall time of the effective pulse is prevented from being lengthened, and the diaphragm is displaced at high speed to achieve multi-nozzle and high density. In addition, an ink jet printer that can perform a printing process at a high speed, generates a first voltage waveform and a second voltage waveform with a simple configuration, and can further improve image quality with a cheap and simple configuration. It is an object of the present invention to provide a head driving method.

[0020]

According to a first aspect of the present invention, there is provided a method of driving an ink-jet head, comprising: a plurality of liquid chambers filled with ink; A plurality of nozzles for discharging, a common liquid chamber that communicates with each of the liquid chambers through an ink flow path and supplies the ink to the liquid chamber, a diaphragm provided in a part of each of the liquid chambers, and the respective vibration plates An actuator unit having an individual electrode disposed opposite to the first electrode with a predetermined gap, and a first drive voltage having a predetermined first voltage waveform having a predetermined first voltage applied to the individual electrode. And a second driving voltage having a predetermined second voltage waveform having a predetermined second voltage is applied to the diaphragm, and an electrostatic force generated by the first driving voltage and the second driving voltage is applied. Deforms the diaphragm to generate pressure in the liquid chamber A method for driving an ink jet head for discharging the ink in the liquid chamber from the nozzles, wherein the first drive voltage and the second drive voltage are different in polarity of their voltage waveforms from each other. The above object is achieved by applying the voltage within a predetermined synchronization period of the driving period of the diaphragm.

According to the above configuration, the diaphragm provided in a part of each of the plurality of liquid chambers to which the ink is supplied from the supply liquid chamber through the ink flow path, and a predetermined gap is provided between the diaphragms. A first drive voltage having a predetermined first voltage waveform having a predetermined first voltage is applied to the individual electrodes disposed opposite to each other, and a predetermined drive voltage is applied to the diaphragm. A second driving voltage having a predetermined second voltage waveform having a second voltage is applied, and the diaphragm is deformed by an electrostatic force generated by the first driving voltage and the second driving voltage to form a liquid chamber. When the pressure is generated and the ink in the liquid chamber is ejected from the nozzles, the first drive voltage and the second drive voltage are changed in polarity of their voltage waveforms from each other, and during the drive period of the diaphragm. Since it is applied within a predetermined synchronization period, the first voltage of the first drive voltage The diaphragm can be displaced in a state corresponding to the voltage waveform in which the shape and the second voltage waveform of the second drive voltage are superimposed, and the displacement of the diaphragm is complicatedly controlled with a simple voltage waveform to eject ink. The image quality can be improved by changing the state in various ways, and the power supply voltage value can be reduced while ensuring the substantial applied voltage.

According to a second aspect of the present invention, there is provided a method for driving an ink jet head, comprising: a plurality of liquid chambers filled with ink; and a plurality of nozzles communicating with the respective liquid chambers and discharging the ink in the liquid chambers. A common liquid chamber that communicates with each of the liquid chambers via an ink flow path and supplies the ink to the liquid chambers; a diaphragm provided in a part of each of the liquid chambers; and a predetermined gap between the respective vibration plates. And an actuator unit having an individual electrode disposed to face each other, wherein one of the individual electrode and the diaphragm is a common electrode, and a predetermined first voltage having a predetermined first voltage is applied to the individual electrode. Applying a first drive voltage of one voltage waveform and applying a second drive voltage of a predetermined second voltage waveform having a predetermined second voltage to the diaphragm, And the electrostatic force generated by the second drive voltage Rotation plate is deformed to generate a pressure in the liquid chamber, a driving method for an ink jet head for discharging the ink of the liquid chamber from the nozzle,
The first driving voltage and the second driving voltage are applied within a predetermined synchronization period of the driving period of the diaphragm while making the polarities of the voltage waveforms different from each other, and at least the nozzles perform recording. The above-mentioned object is achieved by applying one of the first drive voltage and the second drive voltage at all times during the recording area.

According to the above arrangement, the diaphragm provided in a part of each of the plurality of liquid chambers to which the ink is supplied from the supply liquid chamber through the ink flow path and a predetermined gap is provided between the respective vibration plates. One of the individual electrodes disposed to face each other is used as a common electrode, and a first drive voltage having a predetermined first voltage waveform having a predetermined first voltage is applied to the individual electrode. A second driving voltage having a predetermined second voltage waveform having a predetermined second voltage is applied to the diaphragm, and the diaphragm is vibrated by an electrostatic force generated by the first driving voltage and the second driving voltage. When the pressure is generated in the liquid chamber by deforming the plate and the ink in the liquid chamber is ejected from the nozzle, the first drive voltage and the second drive voltage are made to have different polarities of their voltage waveforms. Is applied within a predetermined synchronization period of the diaphragm driving period. Since at least one of the first drive voltage and the second drive voltage is always applied while at least the nozzle is in the recording area at the time of printing, it is possible to apply the drive voltage without using the diaphragm as an individual electrode. Switching processing for the simple, inexpensive configuration, corresponding to the voltage waveform of the first voltage of the first drive voltage and the second voltage waveform of the second drive voltage overlapped The diaphragm can be displaced in a state, and the displacement of the diaphragm can be complicatedly controlled with a simple voltage waveform to change the ink ejection state in various ways, thereby improving the image quality and realizing a low-cost and easy realization. The power supply voltage value can be reduced while ensuring a proper applied voltage.

In each of the above cases, for example, as set forth in claim 3, in the method of driving an ink jet head, the first drive voltage and the second drive voltage are set to the plurality of individual electrodes and the plurality of individual electrodes. Of the diaphragms, the individual electrode and the diaphragm corresponding to the nozzle required to discharge the ink may be individually selected and applied.

According to the above configuration, the first drive voltage and the second drive voltage are applied to the plurality of individual electrodes and the plurality of diaphragms.
Since individual electrodes and diaphragms corresponding to the nozzles required to discharge ink are individually selected and applied,
The diaphragm can be displaced with a plurality of different displacement amounts and displacement speeds in accordance with a combination of the first voltage waveform and the second voltage waveform, so that dot formation is multi-valued and image quality is further improved. be able to.

Also, for example, as described in claim 4, in the method of driving an ink jet head, the first voltage waveform and the second voltage waveform may be opposite to each other with the first drive voltage having the opposite polarities. The second drive voltage may be applied to the individual electrodes and the diaphragm in synchronization with each other and simultaneously.

According to the above configuration, the first drive voltage and the second drive voltage having the first voltage waveform and the second voltage waveform having mutually opposite polarities are synchronized with each other and simultaneously vibrate with the individual electrode. Since it is applied to the plate, it is possible to prevent the rise / fall time of the effective pulse from becoming long, and even when the diaphragm is displaced at a high speed to achieve multi-nozzle and high density,
Printing can be performed at high speed.

Further, for example, as described in claim 5, the first voltage waveform and the second voltage waveform have opposite polarities, and the absolute value of the first voltage and the second voltage waveform are different from each other. The absolute values of the two voltages may be the same value.

According to the above configuration, the first voltage waveform and the second voltage waveform have opposite polarities, and the absolute value of the first voltage and the absolute value of the second voltage are the same. Therefore, the first voltage waveform and the second voltage waveform can be generated with a simple configuration, and image quality can be improved with a cheap and simple configuration.

Further, for example, at least one of the first voltage waveform and the second voltage waveform may be a voltage waveform composed of a plurality of pulse groups. .

According to the above configuration, at least one of the first voltage waveform and the second voltage waveform is a voltage waveform composed of a plurality of pulse groups. Can be ejected as a plurality of ink droplets corresponding to the above, and by controlling the number of pulses, the dot formation can be multi-valued and the image quality can be further improved.

Further, for example, as described in claim 7, the first voltage waveform and the second voltage waveform have opposite polarities, and even if their polarities alternately change. Good.

According to the above configuration, the first voltage waveform and the second voltage waveform have mutually opposite polarities, and their polarities are alternately changed. The residual charge remaining can be appropriately removed, the displacement of the diaphragm can be optimized, and the image quality can be further improved.

For example, as described in claim 8, the first voltage waveform and the second voltage waveform have an absolute value of the first voltage and an absolute value of the second voltage having the same polarity. The values may be the same value.

According to the above configuration, the first voltage waveform and the second voltage waveform have the same absolute value of the first voltage and the absolute value of the second voltage of the same polarity. The first voltage waveform and the second voltage waveform can be generated with a simple configuration, and the displacement of the diaphragm can be optimized by appropriately removing the residual charges remaining between the individual electrodes and the diaphragm. The image quality can be further improved with a cheap and simple configuration.

Further, for example, as described in claim 9, the first voltage waveform and the second voltage waveform are the same waveform, and may have different polarities and different phases.

According to the above configuration, the first voltage waveform and the second voltage waveform are the same waveform, have mutually different polarities and different phases, so that the first voltage waveform and the second voltage waveform are different from each other. The voltage waveform can be generated with a simple configuration, the residual charge remaining between the individual electrodes and the diaphragm can be appropriately removed, and the displacement of the diaphragm can be optimized. The quality can be further improved.

For example, in the method for driving an ink jet head, the first voltage waveform and the second voltage waveform may have the same waveform and have opposite polarities. The first drive voltage and the second drive voltage may be applied to the individual electrodes and the diaphragm in synchronization with each other and simultaneously.

According to the above configuration, the first voltage waveform and the second voltage waveform are the same waveform, and the first drive voltage and the second drive voltage having opposite polarities are synchronized with each other, and At the same time, since the voltage is applied to the individual electrodes and the diaphragm, it is possible to prevent the rise / fall time of the effective pulse from being lengthened. In addition, high-speed printing can be performed, and the first voltage waveform and the second voltage waveform can be generated with a simple configuration, and the image quality can be further improved with a cheap and simple configuration. Can be.

[0040]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are preferred embodiments of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. The embodiments are not limited to these embodiments unless otherwise specified.

FIGS. 1 to 15 show an embodiment of a method for driving an ink jet head according to the present invention.
1 is an exploded perspective view of an electrostatic inkjet head 1 to which an embodiment of the inkjet head driving method of the present invention is applied, and FIG. 2 is a sectional view of a main part of the inkjet head 1 of FIG.

In FIG. 1, the ink jet head 1
A filter 3 on a joint 2 for supplying ink from an ink supply tank or an ink cartridge.
The heat-welded frame 4 is adhesively bonded to the
As shown in FIG. 2, an actuator unit 7 in which a nozzle plate 6 is adhesively bonded to an electrostatic actuator 5 is bonded thereto.

The electrostatic actuator 5 is formed by etching silicon, and a plurality of individual electrodes 8 are formed on the upper surface of the electrostatic actuator 5 as shown in FIG. A pressurized liquid chamber (liquid chamber) 9 is formed at an opposing position on the individual electrode 8, and a diaphragm 10 is formed on the bottom surface of the pressurized liquid chamber 9. A common liquid chamber channel 11 is formed in the center of the electrostatic actuator 5. Electrostatic actuator 5 and nozzle plate 6
A fluid resistance (ink flow path) 12 that communicates the common liquid chamber flow path 11 and each pressurized liquid chamber 9 is defined between the fluid resistance 12 and the common liquid chamber 12. The ink in the flow path 11 is supplied to each pressurized liquid chamber 9.

The nozzle plate 6 is generally formed by a Ni electroforming method, and the nozzle plate 6 is formed with a nozzle hole 13 communicating with each pressurized liquid chamber 9. The nozzle plate 6 discharges the ink in the pressurized liquid chamber 9 from the nozzle holes 13 onto a recording medium such as paper.

The frame 4 has an ink flow path 14 communicating with the common liquid chamber flow path 11 and an insertion groove 15. The ink flow path 14 has an ink supply tank or an ink cartridge. To joint 2
Is supplied through the ink passage 14, and the ink flow path 14 supplies the supplied ink to the common liquid chamber flow path 11 of the electrostatic actuator 5.

The insertion groove 15 of the frame 4 has a driver I
FPC with C16 mounted by wire bonding
The cable 17 is inserted, and the FPC cable 17 is electrically connected to the individual electrodes 8 of the electrostatic actuator 5 by an anisotropic conductive film.

In order to seal a pressure chamber between the individual electrode 8 and the diaphragm 10, a diaphragm gap sealing is provided on an outer portion of the diaphragm 10 between the electrostatic actuator 5 and the nozzle plate 6. Agent 18 is applied and the nozzle plate 6
A nozzle plate sealant 19 is applied between the corners of the frame and the frame 4.

Next, an example of assembling the actuator unit 7 in which the electrostatic actuator 5 and the nozzle plate 6 are joined will be described.

The electrostatic actuator 5 and the nozzle plate 6
An adhesive is applied to the upper surface of the electrostatic actuator 5 in order to join the nozzles. However, if the adhesive overflows at the time of joining with the nozzle plate 6, the ink ejection characteristics are affected. To about 1 μm. In this case, as a method of applying an adhesive to the upper surface of the electrostatic actuator 5 where the pressurized liquid chamber 9 is formed, for example, a transfer method can be used. In the transfer method, for example, the adhesive is thinned to a roller with a doctor blade, the adhesive is transferred from the roller to a transfer pad, and the adhesive is further transferred from the transfer pad to the upper surface of the electrostatic actuator 5.

Next, the diaphragm gap sealant 18 is applied to the outer portion of the diaphragm 10 between the electrostatic actuator 5 and the nozzle plate 6 as described above. The diaphragm gap sealant 18 is applied to seal the gap (the entrance of the vibration chamber) of the diaphragm 10 to prevent moisture from entering the inside of the vibration chamber and displacing the diaphragm 10. It is.

A nozzle plate sealant 19 is applied between the corners of the nozzle plate 6 and the frame 4 to position the nozzle plate 6 and the electrostatic actuator 5. As the nozzle plate sealant 19, an ultraviolet-curing adhesive or an instant adhesive for temporary joining is used.

Then, the nozzle plate 6 formed by Ni electroforming and the electrostatic actuator 5 having the adhesive applied on its upper surface are aligned with each other, and a temporary pressurization is performed. In this case, if the adhesive to be used is an ultraviolet-curable adhesive, the adhesive is cured by irradiating ultraviolet rays, and is subjected to main pressure to be heated and cured, thereby joining the nozzle plate 6 and the electrostatic actuator 5. Then, the actuator unit 7 is assembled. If the electrostatic actuator 5 is long at the time of the heat bonding, the silicon forming the electrostatic actuator 5 and the nozzle plate 6 usually formed of Ni or SUS are warped due to a difference in linear expansion coefficient. appear. When this warpage occurs, the electrostatic actuator 5 may be broken due to internal stress. Therefore, as the adhesive, it is preferable that the curing temperature is lower. Therefore, a two-component mixed type (room temperature curing type) epoxy adhesive is desirable. As the curing temperature of the adhesive, the lower the better, the better, but preferably from 40C to 100C.

When the actuator unit 7 is assembled by joining the electrostatic actuator 5 and the nozzle plate 6 as described above, next, the joint 2 and the frame 4 to which the filter 3 is heat-welded are bonded and joined. An adhesive is applied to the upper surface of the frame 4 that has been joined to the joint portion 2 to align the actuator 4 with the actuator unit 7.
The actuator unit 7 is adhesively bonded to the upper surface of the frame 4.

When the ink-jet head 1 is assembled in the above procedure, the ink-jet head 1 is usually deformed toward the individual electrode 8 by an electrostatic force when a pulse driving voltage is applied to the individual electrode 8 and the volume of the ink-jet head 1 is increased. Ink flows into the increased pressurized liquid chamber 9 from the common liquid chamber flow path 11 through the fluid resistance 12. Here, when the pulse voltage applied to the individual electrode 8 is released, the electrostatic force acting on the diaphragm 10 disappears, and the diaphragm 10 returns to the original state. The pressure in the pressurized liquid chamber 9 increases due to the elastic force of the vibration plate 10, and ink is ejected from the nozzle holes 13.

Next, the operation of the present embodiment will be described. In the inkjet head 1, when the pulse voltage is applied to the individual electrode 8 and then the application of the pulse voltage is released, the diaphragm 10 that has been deformed in the direction of the individual electrode 8 due to the electrostatic force returns. Due to the pressure increase in the pressurized liquid chamber 9, ink is ejected from the nozzle holes 13.

Conventionally, as shown in FIG. 3, a drive waveform generation circuit of the driver IC is used to generate a drive voltage waveform at an effective maximum drive frequency at least according to a reference signal of an ink jet head in a print recording area. Generate. Then, when ejection of ink droplets from the nozzle corresponding to the print pattern is requested in accordance with the printing pattern, the switching circuit applies the drive voltage of the generated drive voltage waveform to the actuator corresponding to the nozzle in the switching circuit. The voltage is applied to the individual electrode corresponding to the nozzle required to be driven.

When a driving voltage is applied to the individual electrode, the diaphragm disposed opposite to the individual electrode is grounded, and therefore, the electrostatic force generated by the driving voltage applied to the individual electrode causes the diaphragm to be grounded. When the diaphragm is displaced in the direction of the individual electrode and the application of the drive voltage is released, the diaphragm returns and the displacement amount
An ink droplet corresponding to the displacement speed is ejected from the nozzle.

When driving is performed with such a driving voltage waveform,
As described above, the diaphragm cannot be displaced in various states, and improvement is required to improve image quality.

Therefore, in the ink jet head 1 of the present embodiment, as shown in FIG. 4, pulses of opposite polarities out of phase are applied from the driver IC 16 to the individual electrodes 8 and the diaphragm 10. FIG. 4 corresponds to claim 1.

That is, the diaphragm 10 is made into an individual electrode, and the same reference signal is used as a trigger to drive the driving voltage (first driving voltage) of the first voltage waveform (first voltage waveform) shown in FIG. In the same manner as in the above case, the second voltage waveform (second voltage waveform) is applied to the individual electrode 8 to have a polarity different from that of the first voltage waveform and a phase delayed by a predetermined amount from the first voltage waveform. A voltage (second drive voltage) is applied to diaphragm 10.

In this case, the driving voltage generating circuit of the driver IC 16 generates the first voltage waveform for the individual electrode 8 and the second voltage waveform for the diaphragm 10, and converts the driving voltage of the first voltage waveform to the first voltage waveform. In other words, the switching circuit for the individual electrode 8 selects and applies the individual electrode 8 to which the driving voltage of the first voltage waveform is applied, and applies the driving voltage of the second voltage waveform to the second voltage waveform, that is, Diaphragm 10 for applying a drive voltage having the second voltage waveform by a switching circuit for diaphragm 10
Is selected and applied.

Therefore, the first voltage waveform and the second voltage waveform are applied in synchronization with each other, and the diaphragm 10 is displaced in a state corresponding to the voltage waveform obtained by superposing the respective voltage waveforms.

The first voltage waveform and the second voltage waveform are
Although the driving voltage waveform is simple, a complicated displacement of the diaphragm 10 can be controlled by appropriately combining the first voltage waveform and the second voltage waveform.

Therefore, the displacement amount and the displacement speed of the vibration plate 10 can be controlled to be optimal for the image to be formed, and the image quality can be improved.

Further, the power supply voltage value can be reduced while substantially applying the applied voltage.

Hereinafter, examples of driving waveforms in the case where the first voltage waveform and the second voltage waveform are variously changed as the voltage waveform of the driving voltage will be described.

First, FIG. 5 shows that the individual electrodes 8 are
7 shows a driving waveform when a driving voltage of a second voltage waveform of the opposite polarity synchronized with the above is applied every time a reference signal is generated, that is, at an effective maximum driving frequency. is there.

In this example of the driving waveform, a voltage waveform is constantly applied at least when the ink jet head 1, especially the nozzle hole 13 is in the printing recording area during printing, and the diaphragm 10 is connected to the common electrode. Has become. And
A drive voltage having a first voltage waveform is applied to the individual electrode 8 corresponding to the nozzle hole 13 for which ink ejection is required, and a drive voltage having a second voltage waveform having a polarity different from that of the first voltage waveform is Each time the reference signal is generated, it is applied to the diaphragm 10.

Accordingly, the diaphragm 10 is displaced in a state corresponding to a voltage waveform obtained by superimposing each of the first voltage waveform and the second voltage waveform having a polarity different from that of the first voltage waveform. When a drive voltage having a voltage waveform is applied, the displacement amount and the displacement speed of the vibration plate 10 necessary for ink ejection are secured, and ink droplets are ejected from the nozzle holes 13.

When only the drive voltage having the second voltage waveform is applied alone, the diaphragm 10 does not undergo displacement required for ink ejection, and no ink droplets are ejected from the nozzle holes 13. .

Further, in this case, it is not necessary to form the diaphragm 10 into individual electrodes as in the case of FIG. 4, so that the electrode configuration can be simplified and the switching for applying the second voltage waveform is performed. The circuit can be simplified as compared with the case of FIG.

FIG. 6 shows a case where a driving voltage having a first voltage waveform is applied to the individual electrodes 8 and the diaphragms 10 which are individual electrodes are individually selected to drive a second voltage waveform having a polarity opposite to that of the first voltage waveform. This applies a voltage, and corresponds to claim 3.

In the case of this driving waveform example, the driving voltage of the first voltage waveform is applied to the individual electrode 8 corresponding to the nozzle hole 13 for which ink ejection is required.

The vibrating plate 10 is formed as an individual electrode, and the vibrating plate 1 corresponding to the nozzle hole 13 for discharging ink droplets by a switching circuit capable of individually selecting the vibrating plate 10.
By selecting 0, a drive voltage having a second voltage waveform having a polarity different from that of the first voltage waveform is applied to the diaphragm 10 selected by the switching circuit.

Therefore, when the respective voltage waveforms are superimposed on the diaphragm 10, a voltage waveform different from the case where the first voltage waveform and the second voltage waveform are applied independently is applied. The diaphragm 10 is displaced as if the first voltage waveform and each of the second voltage waveforms having different polarities from the first voltage waveform are superimposed, and the driving voltage of the first voltage waveform is applied. Then, the amount of displacement and the displacement speed of the vibration plate 10 necessary for ink ejection are secured, and ink droplets are ejected from the nozzle holes 13.

When only the drive voltage having the second voltage waveform is applied alone, the diaphragm 10 does not undergo displacement required for ink ejection, and no ink droplets are ejected from the nozzle holes 13. .

As a result, although the first voltage waveform and the second voltage waveform are simple driving voltage waveforms, the complex displacement of the diaphragm 10 is controlled by appropriately combining the first voltage waveform and the second voltage waveform. can do.

Therefore, the displacement amount and the displacement speed of the vibration plate 10 can be controlled to the optimum state for the image to be formed, and the image quality can be improved.

Further, the power supply voltage value can be reduced while the substantial applied voltage is secured.

FIG. 7 is a diagram in which a first voltage waveform and a second voltage waveform having a polarity opposite to that of the first voltage waveform are simultaneously applied to the individual electrode 8 and the diaphragm 10 in synchronization with the reference signal.
This corresponds to claim 4.

In the case of this example of the drive waveform, the drive voltage of the first voltage waveform is applied to the individual electrode 8 corresponding to the nozzle hole 13 for which ink ejection is required.

Then, a driving voltage of a second voltage waveform having a polarity opposite to that of the first voltage waveform is applied to the diaphragm 10 in synchronization with the reference signal and simultaneously with the first voltage waveform.

Therefore, the rise / fall of the voltages of the first voltage waveform and the second voltage waveform, which are pulses of opposite polarities, can be performed simultaneously, and the rise / fall time of the effective pulse becomes longer. Can be prevented.

As a result, the displacement speed of the diaphragm 10 can be improved, and even when a large number of nozzle holes 13 are formed at a high density, the inkjet head 1 is driven at a high speed to achieve multi-nozzle operation. It can respond to density increase.

FIGS. 8 and 9 show the first voltage waveform applied to the individual electrode 8 and the second voltage waveform applied to the diaphragm 10 having different polarities but the same absolute value of the voltage. This corresponds to claim 5.

In the case of this driving waveform example, first, in FIG.
A drive voltage having a first voltage waveform is applied to the individual electrode 8 corresponding to the nozzle hole 13 for which ink ejection is required.

Then, a driving voltage of a second voltage waveform having a polarity opposite to that of the first voltage waveform and having the same absolute value but a larger pulse width than the first voltage waveform is applied to the diaphragm 10. You.

In FIG. 9, as in the case of FIG. 8, the individual electrodes 8 corresponding to the nozzle holes 13 for which ink ejection is required
The driving voltage having the first voltage waveform is applied to the diaphragm 1
To 0, a drive voltage of a second voltage waveform having a polarity opposite to that of the first voltage waveform and having the same absolute value but a smaller pulse width than the first voltage waveform is applied for each reference signal.

Therefore, although the first voltage waveform and the second voltage waveform are simple driving voltage waveforms, the complex displacement of the diaphragm 10 can be controlled by appropriately combining the first voltage waveform and the second voltage waveform. As a result, the displacement amount and the displacement speed of the diaphragm 10 can be controlled to be optimal for the image to be formed, and the image quality can be improved.

Further, since the absolute values of the first voltage waveform and the second voltage waveform are the same, the driving waveform generating circuit can be simplified.

FIG. 10 shows an example of a driving waveform for applying a first voltage waveform composed of a plurality of pulse groups to the individual electrodes 8, which corresponds to claim 6.

In the case of this driving waveform example, a driving voltage having a first voltage waveform composed of a plurality of pulse groups is applied to the individual electrode 8 corresponding to the nozzle hole 13 for which ink ejection is required, and A drive voltage having a second voltage waveform composed of one pulse having a polarity different from that of the first voltage waveform is applied.

The first voltage waveform is a waveform in which a plurality of ink droplets corresponding to the number of pulses of the plurality of pulses constituting the first voltage waveform are ejected from the nozzle holes 13 and is composed of a plurality of pulses. A plurality of ink droplets ejected from the nozzle holes 13 with the driving voltage of the first voltage waveform is a voltage waveform that combines as one dot.

Therefore, by variably controlling the number of pulses of the pulse group constituting the first voltage waveform, it is possible to variably control the number of dots formed and to further improve image quality.

In FIG. 10, the drive voltage of the second voltage waveform is applied at the timing of applying the drive voltage of the first voltage waveform, as in the case of FIG. , FIG. 10 to FIG.
Any of the above may be used. Also, in FIG. 10, the first voltage waveform is a waveform composed of a group of pulses, but the second voltage waveform may be a waveform composed of a group of pulses,
Both the first voltage waveform and the second voltage waveform may be a waveform composed of a pulse group.

FIGS. 11 and 12 show examples of driving waveforms in which the first voltage waveform applied to the individual electrode 8 and the second voltage waveform applied to the diaphragm 10 are applied by alternately changing the polarity for each reference signal. This corresponds to claim 7.

In the case of this driving waveform example, the driving voltage of the first voltage waveform is applied to the individual electrode 8 corresponding to the nozzle hole 13 for which ink ejection is required, and the first voltage waveform and the polarity are applied to the diaphragm 10. Are applied to each other.

In FIG. 11, the drive voltage of the second voltage waveform is applied only when the drive voltage of the first voltage waveform is applied. In FIG. 12, the drive voltage of the second voltage waveform is applied. The polarity is inverted for each reference signal.

Therefore, although the first voltage waveform and the second voltage waveform are simple driving voltage waveforms, the complex displacement of the diaphragm 10 can be controlled by appropriately combining the first voltage waveform and the second voltage waveform. Thus, the displacement amount and the displacement speed of the vibration plate 10 can be controlled to be optimal for an image to be formed, image quality can be improved, and the drive waveform generation circuit can be simplified. In addition, the inkjet head 1 can be inexpensive.

Further, since the polarity of the first voltage waveform and the polarity of the second voltage waveform are alternately inverted for each reference signal, the residual charge can be further reduced, and the ink discharge performance can be further improved. As a result, the image quality can be further improved.

FIG. 13 shows that the first voltage waveform applied to the individual electrode 8 and the second voltage waveform applied to the diaphragm 10 are alternately inverted in polarity for each reference signal, and the absolute value of the voltage is changed for each reference signal. This is a driving waveform example in which the magnitudes of the voltages of the same polarity are switched alternately and the absolute values of the voltages of the same polarity are set to the same value.

In the case of this driving waveform example, the individual electrodes 8
A drive voltage having a first voltage waveform in which the polarity is alternately inverted for each reference signal and the absolute value of the voltage alternates between large and small for each reference signal is applied.

The diaphragm 10 has a polarity opposite to that of the first voltage waveform and is alternately inverted for each reference signal, and the absolute value of the voltage alternates between large and small for each reference signal. A drive voltage having a second voltage waveform is applied.

Then, the first voltage waveform and the second voltage waveform are
At the same polarity, the absolute value of the voltage is the same value.

Therefore, although the first voltage waveform and the second voltage waveform are simple driving voltage waveforms, a complicated displacement of the diaphragm 10 can be controlled by appropriately combining the first voltage waveform and the second voltage waveform. In addition, the displacement amount and the displacement speed of the diaphragm 10 can be controlled to an optimum state for an image to be formed, and the image quality can be improved. The head 1 can be inexpensive.

The polarity of the first voltage waveform and the polarity of the second voltage waveform are alternately inverted for each reference signal, and the absolute value of the voltage is changed for each reference signal, and has the same value with the same polarity. Therefore, the residual charges can be further alleviated, the ink ejection performance can be further improved, and the image quality can be further improved.

FIG. 14 shows an example of a driving waveform in which the first voltage waveform applied to the individual electrode 8 and the second voltage waveform applied to the diaphragm 10 have the same waveform, and the polarity is inverted for each reference signal. Which corresponds to claim 9.

In this example of the drive waveform, the drive voltage of the first voltage waveform whose polarity is inverted is applied to the individual electrode 8 corresponding to the nozzle hole 13 for which ink ejection is required for each reference signal.

A drive voltage having a second voltage waveform having the same waveform as the first voltage waveform and opposite in polarity to the first voltage waveform is applied to the diaphragm 10.

The first voltage waveform is synchronized with the reference signal, but the second voltage waveform is later than the second voltage waveform by a predetermined phase.

Therefore, the first voltage waveform and the second voltage waveform are simple driving voltage waveforms, but by appropriately combining the first voltage waveform and the second voltage waveform, complicated displacement of the diaphragm 10 can be controlled. Thus, the displacement amount and the displacement speed of the vibration plate 10 can be controlled to be optimal for an image to be formed, image quality can be improved, and the drive waveform generation circuit can be simplified. In addition, the inkjet head 1 can be made inexpensive.

Further, since the first voltage waveform and the second voltage waveform have the same waveform and the polarity is inverted for each reference signal, the residual charge can be further reduced, and the ink can be further reduced. By improving the ejection performance, the image quality can be further improved.

FIG. 15 is an example of a driving waveform in which the first voltage waveform applied to the individual electrode 8 and the second voltage waveform applied to the diaphragm 10 are the same waveform, have opposite polarities, and are synchronized. , Corresponding to claim 10.

In the case of this driving waveform example, the first voltage waveform applied to the individual electrode 8 and the second voltage waveform applied to the diaphragm 10 have the same waveform pulse, and only the polarity is the driving waveform of the opposite polarity. With the reference signal as a trigger, the first voltage waveform and the second voltage waveform are respectively changed to the individual electrode 8 and the diaphragm 1.
0 are applied simultaneously.

Therefore, the first voltage waveform and the second voltage waveform are simple driving voltage waveforms, but by appropriately combining the first voltage waveform and the second voltage waveform, complicated displacement of the diaphragm 10 can be controlled. Thus, the displacement amount and the displacement speed of the vibration plate 10 can be controlled to be optimal for an image to be formed, image quality can be improved, and the drive waveform generation circuit can be simplified. In addition, the inkjet head 1 can be inexpensive.

Further, since the rise and fall of the voltage of the same waveform pulse having the opposite polarities are performed simultaneously, it is possible to prevent the rise and fall time of the effective pulse from being lengthened. The displacement speed at the time of starting the displacement of No. 10 can be improved. Therefore, even when a large number of nozzle holes 13 are formed with high density, the inkjet head 1 can be driven at a high speed to cope with multi-nozzle and high density.

Although the invention made by the inventor has been specifically described based on the preferred embodiments, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the invention. It goes without saying that it is possible.

[0118]

According to the ink jet head driving method of the first aspect of the present invention, the vibration provided in a part of each of the plurality of liquid chambers to which ink is supplied from the supply liquid chamber through the ink flow path is provided. For the individual electrodes disposed opposite the plate and each diaphragm with a predetermined gap, the individual electrodes have a first voltage waveform of a predetermined first voltage having a predetermined first voltage. A drive voltage is applied, a second drive voltage having a predetermined second voltage waveform having a predetermined second voltage is applied to the diaphragm, and the first drive voltage and the second drive voltage are used. The generated electrostatic force deforms the diaphragm to generate pressure in the liquid chamber,
When discharging the ink in the liquid chamber from the nozzle,
Since the first driving voltage and the second driving voltage are applied within a predetermined synchronization period of the driving period of the diaphragm while making the polarities of their voltage waveforms different from each other, the first driving voltage and the second driving voltage The diaphragm can be displaced in a state corresponding to the voltage waveform in which the voltage waveform of the second drive voltage and the second voltage waveform of the second drive voltage are superimposed, and the displacement of the diaphragm is complicatedly controlled by a simple voltage waveform. The image quality can be improved by variously changing the ink ejection state, and the power supply voltage value can be reduced while ensuring the substantial applied voltage.

According to the ink jet head driving method of the present invention, the diaphragm provided in a part of each of the plurality of liquid chambers to which the ink is supplied from the supply liquid chamber through the ink flow path is provided. One of the individual electrodes disposed opposite to each diaphragm with a predetermined gap therebetween is set as a common electrode, and the individual electrode has a predetermined first voltage having a predetermined first voltage. A first drive voltage having a waveform is applied, and a second drive voltage having a predetermined second voltage waveform having a predetermined second voltage is applied to the diaphragm. When the diaphragm is deformed by the electrostatic force generated by the second drive voltage to generate pressure in the liquid chamber and the ink in the liquid chamber is ejected from the nozzle, the first drive voltage and the second drive voltage The polarities of the voltage waveforms are made different from each other, Since the voltage is applied within a predetermined synchronization period of the moving period and at least one of the first driving voltage and the second driving voltage is always applied at least while the nozzle is in the recording area at the time of recording, the diaphragm is individually applied. Without switching to an electrode, the switching process for applying the driving voltage is simplified, and the first voltage waveform of the first driving voltage and the second voltage of the second driving voltage are formed in a simple and inexpensive configuration. The diaphragm can be displaced in a state corresponding to the superimposed voltage waveform, and the displacement of the diaphragm is complicatedly controlled with a simple voltage waveform to change the ink discharge state in various ways to improve image quality. It is possible to lower the power supply voltage value while securing a substantial applied voltage easily and inexpensively while improving the power supply voltage.

According to the ink jet head driving method of the third aspect of the present invention, the first driving voltage and the second driving voltage are changed to a value required for ink ejection among a plurality of individual electrodes and a plurality of diaphragms. The individual electrode and the diaphragm corresponding to the nozzle that is being selected are individually selected and applied, so that the diaphragm is subjected to a plurality of different displacement amounts and displacements according to the combination of the first voltage waveform and the second voltage waveform. The displacement can be performed at a speed, and the dot formation can be multi-valued, so that the image quality can be further improved.

According to the ink jet head driving method of the invention, the first driving voltage and the second driving voltage having the first voltage waveform and the second voltage waveform having mutually opposite polarities are applied to each other. Since the voltage is applied to the individual electrodes and the diaphragm at the same time as the vibration, the rise / fall time of the effective pulse can be prevented from being lengthened. Even when density is increased, printing processing can be performed at high speed.

According to the ink jet head driving method of the present invention, the first voltage waveform and the second voltage waveform have opposite polarities, and the absolute value of the first voltage and the second voltage waveform are different from each other. Since the absolute values of the voltages are the same, the first voltage waveform and the second voltage waveform can be generated with a simple configuration, and the image quality can be improved with a cheap and simple configuration.

According to the ink jet head driving method of the present invention, at least one of the first voltage waveform and the second voltage waveform is a voltage waveform composed of a plurality of pulse groups. The ink forming one dot can be ejected as a plurality of ink droplets corresponding to the number of pulses, and by controlling the number of pulses, the dot formation can be multi-valued and the image quality can be further improved. .

According to the ink jet head driving method of the present invention, the first voltage waveform and the second voltage waveform have mutually opposite polarities, and the polarities thereof alternately change. Accordingly, the residual charges remaining between the individual electrodes and the diaphragm can be appropriately removed, the displacement of the diaphragm can be optimized, and the image quality can be further improved.

According to the ink jet head driving method of the present invention, the first voltage waveform and the second voltage waveform are converted into the absolute value of the first voltage and the absolute value of the second voltage having the same polarity. However, since it has the same value, the first voltage waveform and the second voltage waveform can be generated with a simple configuration, and the residual charges remaining between the individual electrodes and the diaphragm are appropriately removed, The displacement of the diaphragm can be made appropriate, and the image quality can be further improved with an inexpensive and simple configuration.

According to the ink-jet head driving method of the ninth aspect, the first voltage waveform and the second voltage waveform are the same waveform, have different polarities and different phases. In addition, the first voltage waveform and the second voltage waveform can be generated with a simple configuration, and the displacement of the diaphragm is appropriately adjusted by appropriately removing the residual charges remaining between the individual electrodes and the diaphragm. Thus, the image quality can be further improved with an inexpensive and simple configuration.

According to the ink jet head driving method of the present invention, the first voltage waveform and the second voltage waveform are mutually the same, and the first driving voltage and the second driving voltage having opposite polarities are mutually opposite. Are applied to the individual electrodes and the diaphragm in synchronization with each other and at the same time.
It is possible to prevent the fall time from becoming longer, and to perform high-speed printing even when the diaphragm is displaced at high speed to increase the number of nozzles and increase the density. The waveform and the second voltage waveform can be generated with a simple configuration, and the image quality can be further improved with a cheap and simple configuration.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an inkjet head to which an embodiment of a method for driving an inkjet head according to the present invention is applied.

FIG. 2 is a partially enlarged cross-sectional view of the inkjet head of FIG.

FIG. 3 is a diagram showing a voltage waveform of a driving voltage of a conventional inkjet head and a reference signal.

FIG. 4 is a diagram showing an example of a voltage waveform of a drive voltage of the inkjet head of FIG. 1 and a reference signal.

FIG. 5 is a diagram showing another example of a voltage waveform of a drive voltage of the inkjet head of FIG. 1 and a reference signal.

FIG. 6 is a diagram showing still another example of a voltage waveform of a drive voltage of the inkjet head of FIG. 1 and a reference signal.

FIG. 7 is a diagram showing still another example of a voltage waveform of a drive voltage of the inkjet head of FIG. 1 and a reference signal.

FIG. 8 is a diagram showing still another example of a voltage waveform of a drive voltage of the inkjet head of FIG. 1 and a reference signal.

FIG. 9 is a diagram showing still another example of a voltage waveform of a drive voltage of the inkjet head of FIG. 1 and a reference signal.

FIG. 10 is a diagram showing still another example of a voltage waveform of a drive voltage of the inkjet head of FIG. 1 and a reference signal.

FIG. 11 is a diagram showing still another example of a voltage waveform of a drive voltage of the inkjet head of FIG. 1 and a reference signal.

FIG. 12 is a diagram showing still another example of a voltage waveform of a drive voltage of the inkjet head of FIG. 1 and a reference signal.

FIG. 13 is a diagram showing still another example of a voltage waveform of a drive voltage of the inkjet head of FIG. 1 and a reference signal.

FIG. 14 is a diagram showing still another example of a voltage waveform of a drive voltage of the inkjet head of FIG. 1 and a reference signal.

FIG. 15 is a diagram showing still another example of a voltage waveform of a drive voltage of the inkjet head of FIG. 1 and a reference signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink jet head 2 Joint part 3 Filter 4 Frame 5 Electrostatic actuator 6 Nozzle plate 7 Actuator unit 8 Individual electrode 9 Pressurized liquid chamber 10 Vibrating plate 11 Common liquid chamber flow path 12 Fluid resistance 13 Nozzle hole 14 Ink flow path 15 Insertion groove Reference Signs List 16 driver IC 17 FPC cable 18 diaphragm gap sealant 19 nozzle plate sealant

Claims (10)

[Claims] A plurality of liquid chambers filled with ink, a plurality of nozzles communicating with the respective liquid chambers and discharging the ink in the liquid chambers, and communicating with the respective liquid chambers via ink flow paths. A common liquid chamber that supplies the ink to the liquid chamber, a diaphragm provided in a part of each of the liquid chambers, and an individual electrode disposed to face each of the vibration plates with a predetermined gap therebetween. An actuator unit, wherein a first drive voltage having a predetermined first voltage waveform having a predetermined first voltage is applied to the individual electrode, and a predetermined voltage having a predetermined second voltage is applied to the diaphragm. Applying a second drive voltage of the second voltage waveform, deforming the diaphragm with electrostatic force generated by the first drive voltage and the second drive voltage to generate pressure in the liquid chamber, An inkjet head for discharging the ink in the liquid chamber from the nozzle. A driving method for driving the diaphragm, wherein the first driving voltage and the second driving voltage are applied in a predetermined synchronization period of the driving period of the diaphragm while making the polarities of their voltage waveforms different from each other. A method for driving an ink jet head. 2. A plurality of liquid chambers filled with ink, a plurality of nozzles communicating with the respective liquid chambers and discharging the ink in the liquid chambers, and communicating with the respective liquid chambers via ink flow paths. A common liquid chamber for supplying the ink to the liquid chamber, a vibration plate provided in a part of each of the liquid chambers, and an individual electrode disposed to face each of the vibration plates at a predetermined gap. An actuator unit, wherein one of the individual electrode and the diaphragm is used as a common electrode, and a first drive voltage having a predetermined first voltage waveform having a predetermined first voltage is applied to the individual electrode. And applying a second drive voltage having a predetermined second voltage waveform having a predetermined second voltage to the diaphragm, and applying the electrostatic force generated by the first drive voltage and the second drive voltage to the vibration plate. The diaphragm is deformed to generate pressure in the liquid chamber, and the liquid chamber is A method of driving an ink jet head that discharges the ink from the nozzles, wherein the first driving voltage and the second driving voltage are driven with the polarities of their voltage waveforms being different from each other. A voltage is applied within a predetermined synchronization period of a period, and at least one of the first drive voltage and the second drive voltage is always applied while at least the nozzle is in a print area during printing. Method for driving an inkjet head. 3. The method of driving an ink jet head according to claim 1,
The first drive voltage and the second drive voltage, the plurality of individual electrodes and the plurality of diaphragms, the individual electrodes and the diaphragm corresponding to the nozzles required to discharge the ink. 2. The method of driving an ink jet head according to claim 1, wherein each of these is individually selected and applied. 4. The method of driving an ink-jet head according to claim 1,
The first voltage waveform and the second voltage waveform are applied with the first drive voltage and the second drive voltage having mutually opposite polarities to the individual electrode and the diaphragm in synchronization with each other and simultaneously. 2. The method for driving an ink jet head according to claim 1, wherein: 5. The first voltage waveform and the second voltage waveform have opposite polarities, and the absolute value of the first voltage and the absolute value of the second voltage are the same. 3. The method for driving an ink jet head according to claim 1, wherein: 6. The method according to claim 1, wherein at least one of the first voltage waveform and the second voltage waveform is a voltage waveform composed of a plurality of pulse groups. Driving method of inkjet head. 7. The method according to claim 1, wherein the first voltage waveform and the second voltage waveform have mutually opposite polarities, and the polarities thereof change alternately. 3. The method for driving an ink-jet head according to claim 1. 8. The first voltage waveform and the second voltage waveform are characterized in that the absolute value of the first voltage and the absolute value of the second voltage having the same polarity are the same value. Claim 7
The method for driving an inkjet head according to the above description. 9. The driving method according to claim 7, wherein the first voltage waveform and the second voltage waveform have the same waveform, and have mutually different polarities and different phases. Method. 10. The method of driving an ink-jet head according to claim 1, wherein the first voltage waveform and the second voltage waveform have the same waveform, and the first drive voltage and the second drive voltage having opposite polarities. The voltage is applied to the individual electrodes and the diaphragm in synchronization with each other and simultaneously.
A method for driving an ink jet head according to claim 2.