JPH10202872A - Drive device of ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a necessary number of transistors without lowering the integrated degree of ink chambers, to perform high density dot printing and to achieve the miniaturization and cost reduction of constitution. SOLUTION: Polarized piezoelectric members 21, 22 are laminated and a large number of grooves 23 are formed to them and individual electrodes 24 are formed over the range from both side surfaces constituting the partition walls of the respective grooves to the bottom surface crossing them at a right angle and a common electrode 29 is formed on the bottom surface of the piezoelectric members 21 and the upper parts of the grooves 8 are closed by a top plate 26 and the leading ends of the grooves are closed by an orifice plate provided with ink emitting orifices 28 to form ink chambers. The individual electrodes of the ink chambers are respectively earthed through transistors and the transistors connected to the individual electrodes of the ink chambers having to emit ink are turned ON while the transistors connected to the individual electrodes of the ink chambers adjacent thereto are turned OFF to supply drive pulse signal (s) to the common electrode to emit ink from the ink chambers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus for an ink-jet head in which a plurality of ink chambers separated by a partition made of a polarized electromechanical conversion member are arranged.

[0002]

2. Description of the Related Art Heretofore, as this type of ink jet head, one having a configuration shown in FIGS. 8 and 9 has been known. This is achieved by laminating two piezoelectric members 1 and 2 polarized in directions opposite to each other in the thickness direction as shown by arrows as electromechanical conversion members, and cutting the laminated piezoelectric members 1 and 2 by cutting. A large number of long grooves 3, 3,... Having an opening at the front end and a slanting rear end are formed at regular intervals and in parallel. The electrodes 4, 4,... Are formed on the inner surfaces of the grooves 3, 3,... By electroless plating, and the upper portions of the grooves 3, 3,. , And the end of each groove 3, 3,... Is closed with an orifice plate 7.
Are opened at the positions of the grooves 3, 3,..., So that the grooves 3, 3,... Become ink chambers, and ink is supplied from the ink supply grooves 5 to the respective ink chambers. It has a configuration.

As shown in FIG. 10, in the case of a single power supply driving device, the ink jet head driving device connects the electrodes 4, 4,... Of the ink chambers 9a, 9b, 9c,. Are connected to the + VH terminal of the power supply via
Are grounded via N-type transistors 11a, 11b, 11c,...

[0004] This driving device comprises a PNP transistor 1
0a, 10c ON, PNP transistor 10b O
When the FF and NPN transistors 11b are turned on and the NPN transistors 11a and 11c are turned off, the electrodes 4 of the ink chambers 9a and 9c have the + VH potential and the electrode 4 of the ink chamber 9b has the ground potential. An electric field in a direction orthogonal to the polarization direction is generated in the partition wall of the ink chamber 9b and the partition wall of the ink chambers 9b and 9c, and each partition wall is deformed so as to reduce the volume of the ink chamber 9b. As a result, ink droplets are ejected from the ink ejection port 8 of the ink chamber 9b.

However, since this driving device requires two transistors for one ink chamber, if the number of ink chambers is large, the number of transistors required for the driving device becomes enormous, and the configuration is large. However, there is a problem that the cost is increased and the cost is increased.

To solve such a problem, Japanese Patent Application Laid-Open No. 6-64166 is known. This is because ink chambers for ink ejection and dummy grooves not for ink ejection are alternately arranged, the electrodes of the dummy grooves are commonly connected to form a common electrode, and this common electrode is connected to a + VH terminal or a ground terminal. The configuration is such that the electrodes of each ink chamber are connected to the ground terminal or + VH terminal via a transistor, so that the number of transistors required for one ink chamber is reduced to one and the number of transistors required for the entire apparatus is reduced. Thus, the size of the configuration is reduced and the cost is reduced.

[0007] A drive device for an ink jet head driven by two power supplies is also known. As shown in FIG. 11, the electrodes 4, 4 of the ink chambers 9a, 9b, 9c,.
.. Are respectively PNP transistors 12a, 12b, 1
Are connected to the + VP terminal, which is a positive power supply, through NPN transistors 13a, 13b,.
13c,... Are connected to the -VM terminal which is a negative power supply. The electrodes 4, 4,... Of the ink chambers 9a, 9b, 9c,.
4b, 14c,... And PNP transistors 15a, 15
, 15c,... are grounded through a parallel circuit.

[0008] This driving device comprises a PNP transistor 1
2b and the NPN transistors 14a and 14c are turned on,
PNP transistors 12a, 12c, NPN transistors 13a, 13b, 13c, NPN transistor 14b, and PNP transistors 15a, 15b, 15
When c is turned off, the potential of the electrode 4 of the ink chamber 9b becomes +
VP and the electrodes 4 of the ink chambers 9a and 9c are at the ground potential, so that the partition between the ink chambers 9a and 9b and the ink chamber 9
An electric field in the direction orthogonal to the polarization direction is generated in the partition walls b and 9c, and each partition wall deforms so as to increase the volume of the ink chamber 9b. As a result, the ink supply groove 5 moves from the ink chamber 9b.
Is supplied with ink.

After an appropriate time, an NPN transistor 13b and PNP transistors 15a, 15
c ON, PNP transistors 12a, 12b, 12
c, when the NPN transistors 13a, 13c, the NPN transistors 14a, 14b, 14c and the PNP transistor 15b are turned off, the electrode 4 of the ink chamber 9b is turned off.
Becomes -VM, and the electrodes 4 of the ink chambers 9a and 9c become the ground potential. Therefore, the direction of polarization of the partition between the ink chambers 9a and 9b and the partition between the ink chambers 9b and 9c is orthogonal to the direction of polarization. An electric field in the opposite direction to the previous time is generated, and each partition deforms so as to contract the volume of the ink chamber 9b. As a result, ink droplets are ejected from the ink ejection port 8 of the ink chamber 9b. As described above, the ink discharge performance can be improved by performing the ink discharge by expanding and contracting the ink chamber and then performing the ink discharge. However, this driving device requires four transistors for one ink chamber.

[0010]

As described above, according to the above-mentioned publication, the number of transistors required for one ink chamber is one, and the number of transistors required for the entire apparatus is one that is driven by one power supply. However, since the number of ink chambers and the dummy grooves can be alternately arranged, the degree of integration of the ink chambers for actually ejecting ink is reduced, and the density of the ink chambers is reduced. There was a problem that dot printing was not possible. In the case of driving using the two power supplies described above, four transistors are required for one ink chamber. Therefore, if the number of ink chambers is large, the number of transistors required for the driving device is enormous. Therefore, there is a problem that the configuration becomes large and the cost becomes high.

Therefore, in the invention according to claim 1, when the apparatus is driven by one power supply, the number of transistors required in the entire apparatus can be sufficiently reduced without lowering the degree of integration of the ink chamber, and the high density Provided is an ink-jet head driving device capable of performing dot printing and reducing the size and cost of the configuration.

According to a second aspect of the present invention, in an apparatus driven by two power supplies, the number of transistors required in the entire apparatus can be sufficiently reduced, and the structure can be reduced in size and the cost can be reduced. A head driving device is provided.

[0013]

According to the first aspect of the present invention,
Separated by a partition made of polarized electromechanical conversion members,
A plurality of ink chambers each having an ink discharge port at one end, extending from a partition wall surface of each ink chamber to a surface orthogonal to the partition wall surface, and formed perpendicular to a polarization direction of the partition wall between adjacent ink chambers. Individual electrodes for generating an electric field in the direction of
A common electrode is provided opposite to a part of the individual electrode extending on a surface orthogonal to the partition wall surface of each ink chamber at a predetermined interval, and a switching element connected to the individual electrode of each ink chamber is provided. By selectively turning on and off each switching element, a drive voltage is applied between the individual electrode of the ink chamber to which ink is to be ejected and the common electrode, whereby the individual electrode of the ink chamber to be ejected and ink are ejected. An object of the present invention is to provide a predetermined level of potential difference between the ink chamber adjacent to the ink chamber to be ejected and the individual electrode of the ink chamber, thereby contracting the volume of the ink chamber to be ejected and causing the ink ejection.

According to a second aspect of the present invention, there are provided a plurality of ink chambers which are separated by a partition made of a polarized electromechanical conversion member and provided with an ink discharge port at one end; Individual electrodes for forming an electric field in a direction perpendicular to the direction of polarization of the partition wall between adjacent ink chambers and extending to a plane orthogonal to the ink chamber, and extending to a plane orthogonal to the partition wall surface of each ink chamber. And a plurality of first electrodes connected between the individual electrode of each ink chamber and the positive potential terminal, respectively.
And a plurality of second switching elements respectively connected between the individual electrodes of each ink chamber and the negative potential terminal, and the individual ink chambers to be ejected with the common electrode at the ground potential. The first switching element connected to the electrode is turned on, the second switching element connected to the individual electrode of the ink chamber from which ink is to be discharged is turned off, and the ink chamber adjacent to the ink chamber from which ink is to be discharged is turned off. The first switching element and the second switching element connected to the individual electrodes are turned off to increase the volume of the ink chamber in which ink is to be ejected, and the ink to be ejected with the common electrode at the ground potential. The first switching element connected to the individual electrode of the chamber is turned off, and the second switching element connected to the individual electrode of the ink chamber from which ink is to be ejected.
Ink chamber for discharging ink by turning on the first switching element and turning off the first and second switching elements connected to the individual electrodes of the ink chamber adjacent to the ink chamber for discharging ink In order to discharge ink by reducing the volume.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) This embodiment is an embodiment corresponding to the first aspect, as shown in FIGS. 1 to 3, as shown by arrows in FIG. The two polarized piezoelectric members 21 and 22 are used as electromechanical conversion members, and the piezoelectric member 21 is attached to the lower side and the piezoelectric member 22 is attached to the upper side, and the bonded piezoelectric members 21 and 22 are cut from the upper side. A large number of long grooves 23, 23,... Having an opening at the front end and an oblique rear end inclined upward are formed at regular intervals and in parallel. Each of the grooves 23, 23,...
The individual electrodes 24, 24, 24, 24, 24,
Are formed, and the upper portions of the grooves 23, 23,... Are closed with a top plate 26 formed inside and behind the ink supply grooves 25, and the tips of the grooves 23, 23,.
7 and each groove 2 of this orifice plate 27
Are opened at the positions of 3, 23,.... Each groove 23 surrounded by the top plate 26 and the orifice plate 27 forms an ink chamber for discharging ink.

A common electrode 29 is formed on the bottom surface of the piezoelectric member 21 by electroless plating, and the piezoelectric members 21 and 22 having the common electrode 29 formed thereon are bonded and fixed on a substrate 30. The substrate 30 may be a dielectric such as a piezoelectric member or a non-dielectric. Each of the grooves 23, 2
Lead electrodes 31, 31, ... extending from the individual electrodes 24 are formed by electroless nickel plating on the rear upper surface of the piezoelectric member 22 from the rear ends of the piezoelectric members. Then, a PC board 32 is bonded and fixed to the rear side on the substrate 30,
A drive IC 33 having a built-in drive circuit is mounted on a C plate 32, and conductive patterns 34, 34,... Connected to the drive IC 33 are formed. The conductive patterns 34, 34,. Are connected by conducting wires 35, 35,... By wire bonding.

As shown in FIG. 4, the drive IC 33 has ink chambers 36a, 36 formed of grooves 23, 23,.
, 36c,..., NPN transistors 37a, 37b, 3
, And a driving pulse signal s generating circuit (not shown) connected to the common electrode 29, and the like.

In the driving device having such a configuration, for example, the transistor 37b connected to the individual electrode 24 of the ink chamber 36b for discharging ink is turned on, and the ink chamber 36b is turned on.
When the transistors 37a and 37c connected to the individual electrodes 24 of the ink chambers 36a and 36c adjacent to are turned off,
The individual electrode 24 of the ink chamber 36b is at the ground potential, and the individual electrodes 24 of the adjacent ink chambers 36a and 36c are in a floating state.

When a drive pulse signal s of a voltage VH is applied to the common electrode 29 in this state, the potential of the common electrode 29 becomes VH.
Since the individual electrode 24 of the ink chamber 36b remains at the ground potential, the potential of the individual electrode 24 of the adjacent ink chambers 36a and 36c becomes an intermediate potential between the voltages VH and 0V.
For this reason, a potential difference occurs between the individual electrodes 24 of the ink chambers 36a and 36c and the individual electrodes 24 of the ink chamber 36b, and a partition between the ink chambers 36a and 36c and the ink chamber 36b has
An electric field is generated in a direction perpendicular to the polarization direction of the partition.

As a result, a shear strain is generated in the partition between the ink chambers 36a and 36c and the ink chamber 36b, and each partition is deformed in a direction to reduce the volume of the ink chamber 36b. By this contraction operation, ink droplets are ejected from the ink ejection port 28 of the ink chamber 36b. Thereafter, when the energization of the drive pulse signal s ends, the potential of the common electrode 29 becomes 0V, and the potential of the individual electrodes 24 of the ink chambers 36a and 36c also becomes 0V. When ink is not ejected from the ink chamber 36b, the transistor 37b connected to the individual electrode 24 of the ink chamber 36b is turned off.

In this way, the individual electrodes 24 of the ink chamber 36b are also in a floating state, so that when the drive pulse signal s is applied to the common electrode 29, the ink chambers 36a, 36b, 36
The potentials of the individual electrodes 24c are all intermediate between the voltages VH and 0V. Therefore, no potential difference occurs between the individual electrodes 24 of the ink chambers 36a and 36c and the individual electrodes 24 of the ink chamber 36b, and the partition walls between the ink chambers 36a and 36c and the ink chamber 36b do not deform. That is, ink is not ejected from the ink chamber 36b. When the ink discharge from the ink chamber is prohibited as described above, the transistor connected to the individual electrode 24 of this ink chamber is turned on similarly to the transistor connected to the individual electrode 24 of the adjacent ink chamber.
What is necessary is just to make it into F state.

When the ink jet head having such a configuration is driven, it is desirable to drive the ink jet head in three or more divisions. The 3n + 1th ink chamber is contracted and driven, and then the 3n + 2nd ink chamber is contracted and driven.
Line printing is performed, and this is sequentially repeated to print one page.

This is because, when the individual electrode 24 of a certain ink chamber is in a floating state, of the individual electrodes 24 of the adjacent ink chamber, one of the individual electrodes 24 is grounded, and the other of the individual electrodes 24 on both sides is grounded. The potential of the individual electrode 24 in the ink chamber when the drive pulse signal s is applied to the common electrode 29 is different from that in the case where is grounded. In this case, the driving pattern of the ink chamber is different, and the ink ejection speed varies. In order to eliminate the variation in the ink ejection speed, driving of three or more divisions is required. For example, the drive pulse signal s
Is 24 V, and the diameter of the ink ejection port 28 is 35 μm.
In the case of m, ink can be ejected at an ejection speed of 6 m / sec or more by three-division driving.

As described above, only one transistor may be connected to the individual electrode 24 of each ink chamber, and the common electrode 29 may be connected to one circuit for generating the drive pulse signal s. Therefore, the number of required transistors can be reduced to half that of the conventional one, and the configuration of the entire driving device can be downsized even if a circuit for generating the driving pulse signal s is added.
Cost reduction can also be achieved. Moreover, since all the grooves can be used as ink chambers for ejecting ink without using the dummy grooves, the degree of integration of the ink chambers is not reduced. That is, high-density dot printing can be performed.

(Second Embodiment) This embodiment is an embodiment corresponding to the first aspect, and as shown in FIG.
A constant voltage VH is applied to the line 38 to which the emitters of the PN transistors 37a, 37b, 37c,... Are connected, and a constant voltage VH is also applied to the common electrode 29. The ground potential (0 V) is applied to the line 38 during the ink discharging operation. The negative driving pulse signal s1 is given.

In this driving device, for example, when ink is to be ejected from the ink chamber 36b, the NPN transistor 37b is turned on and the NPN transistor 37 is turned on.
a, 37c are turned off. When the drive pulse signal s1 is applied to the line 38 in this state, the individual electrode 24 of the ink chamber 36b is set to the ground potential, and the individual electrodes 24 of the ink chambers 36a and 36c adjacent to the ink chamber 36b are floating and set to the voltage VH. The potential becomes an intermediate potential from the potential.

For this reason, each partition of the ink chamber 36b is deformed in a direction in which the volume of the ink chamber 36b is contracted by receiving an electric field in a direction perpendicular to the polarization direction. By this contraction operation, ink droplets are ejected from the ink ejection port 28 of the ink chamber 36b.

Also in this embodiment, only one transistor is required to be connected to the individual electrode 24 of each ink chamber, and the number of required transistors can be reduced to half that of the conventional one. Can be downsized, and the cost can be reduced. Moreover, since all grooves can be used as ink chambers for ink ejection without using dummy grooves,
There is no decrease in the degree of integration of the ink chamber. That is,
High-density dot printing is possible.

(Third Embodiment) This embodiment is an embodiment corresponding to claim 2 and has a common electrode 29 grounded as shown in FIG. In addition, the ink chambers 36a, 36
Are connected to + VP power supply terminals which are positive power supplies via PNP transistors 39a, 39b, 39c,.
.. Are connected to a negative power supply terminal -VM power supply via PN transistors 40a, 40b, 40c,.

In this driving device, for example, when ink is to be ejected from the ink chamber 36b, first, P
The NP transistor 39b is turned ON, and the PNP transistors 39a and 39c and the NPN transistor 40
a, 40b, and 40c are turned off. As a result, the potential of the individual electrode 24 of the ink chamber 36b becomes + VP, and the individual electrodes 24 of the adjacent ink chambers 36a and 36c are in a floating state, so that the potential of the individual electrode 24 is intermediate between + VP and the ground potential. Potential. Thereby, the ink chamber 3
Each partition 6b receives an electric field in a direction perpendicular to the polarization direction and deforms in a direction to increase the volume of the ink chamber 36b, so that ink is supplied from the ink supply groove.

Next, the NPN transistor 40b is turned on.
Then, the PNP transistors 39a, 39B, 39c and the NPN transistors 40a, 40c are turned off. As a result, the potential of the individual electrode 24 of the ink chamber 36b becomes -VM, and the individual electrodes 24 of the adjacent ink chambers 36a and 36c are in a floating state.
The potential of 4 is an intermediate potential between -VM and the ground potential. As a result, each partition of the ink chamber 36b is deformed in a direction perpendicular to the polarization direction and in a direction in which the volume of the ink chamber 36b is contracted by receiving an electric field in a direction opposite to that of the previous time.
The ink is ejected from the ink ejection port 28 of b.

As described above, in the case of using two power supplies of the + VP power supply and the -VM power supply, the individual electrodes 24 of each ink chamber are used.
The number of required transistors can be reduced by half compared with the conventional dual power supply driving circuit, the configuration of the entire driving device can be reduced, and the cost can be reduced. it can.

(Fourth Embodiment) This embodiment shows a modification of the ink jet head. As shown in FIG. 7, one piezoelectric member 41 polarized in the thickness direction is used as an electromechanical conversion member. The piezoelectric member 41 has a plurality of elongated grooves 42, 42,... Of which the front end is opened by cutting and the rear end of the piezoelectric member 41 is inclined upward. The grooves 42, 42,.
A plate-shaped insulator 43 is adhesively fixed to the upper surface which is the opening of
The individual electrodes 44, 44,... Are formed by electroless plating from the upper halves of both sides, which are the partition walls of the grooves 42, 42,. A common electrode 45 is formed on the upper surface of 43 by electroless plating, and a top plate 46 is fixed on the common electrode 45. An ink supply groove (not shown) is formed in the top plate 46 as in the first embodiment, and ink discharge ports 47, 47,... Are provided at the tips of the grooves 42, 42,. An ink chamber is formed by closing with an orifice plate (not shown).

In the ink-jet head having such a configuration, when driven by one power supply as shown in the first embodiment, the individual electrodes 44 of the ink chamber for discharging ink are turned on by setting the transistors to ON and setting the voltage to 0V. When a drive pulse signal s of a voltage VH is applied to the common electrode 45 in this state, the potential of the common electrode 45 becomes VH. , And the individual electrode 44 of the ink chamber from which ink is ejected remains at the ground potential. Therefore, the potential of the individual electrode 44 of the adjacent ink chamber becomes an intermediate potential between the voltages VH and 0V. For this reason, a potential difference occurs between the individual electrode 44 of the adjacent ink chamber and the individual electrode 44 of the ink chamber that discharges ink, and each partition between the ink chamber that discharges ink and the adjacent ink chamber deforms. The volume of the ink chamber in which ink is discharged contracts, and ink is discharged.

Therefore, even in the case where the ink-jet head is driven by one power supply, similarly to the first embodiment, the number of transistors connected to the individual electrodes 44 of each ink chamber can be reduced to one. Even if a pulse signal s generating circuit is added, the configuration of the entire driving device can be reduced in size and cost can be reduced. Moreover, since all the grooves can be used as ink chambers for ejecting ink without using the dummy grooves, the degree of integration of the ink chambers is not reduced. That is, high-density dot printing can be performed.

When the ink-jet head is driven by two power supplies as shown in the third embodiment, the individual electrodes 44 of the ink chamber for discharging ink are connected to the PNP.
Type transistor ON, NPN type transistor OFF
To the + VP potential, and the individual electrodes 44 in the ink chamber adjacent to this ink chamber are turned off by turning off the PNP transistor and the NPN transistor, so that each partition of the ink chamber for discharging ink is orthogonal to the polarization direction. In this case, an electric field is applied in a direction to increase the volume of the ink chamber 36b, thereby supplying the ink.
F, the NPN type transistor is turned on to set the potential at -VM, and the individual electrode 44 of the ink chamber adjacent to this ink chamber is set to the PNP type transistor and the NPN type transistor to the OF potential.
F to make it in a floating state, an electric field is applied to each partition of the ink chamber where ink is ejected in a direction perpendicular to the polarization direction and in a direction opposite to that of the previous time to reduce the volume of the ink chamber 36b. Ink is ejected from the ink chamber where the ink is ejected.

Therefore, in the case of driving with two power supplies using this ink jet head, as in the third embodiment, only two transistors are required to be connected to the individual electrodes 24 of each ink chamber, respectively. The number of required transistors can be reduced to half that of the conventional two-power-supply driving circuit, and the overall configuration of the driving device can be reduced in size and cost can be reduced.

[0038]

As described above, according to the first aspect of the present invention, 1
In a device driven by one power supply, there is no need to provide a dummy groove, so that the integration degree of the ink chamber is not reduced, and one transistor may be connected to one electrode of the ink chamber. The required number of transistors can be sufficiently reduced, whereby high-density dot printing can be performed, and the size of the configuration can be reduced and the cost can be reduced. According to the second aspect of the present invention, in a device driven by two power supplies, the number of transistors required in the entire device can be sufficiently reduced, so that the configuration can be downsized and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a partially exploded perspective view showing a configuration of an inkjet head according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of the inkjet head according to the embodiment.

FIG. 3 is a partial vertical cross-sectional view of the inkjet head according to the embodiment.

FIG. 4 is a diagram showing a partial configuration of a driving device of the inkjet head according to the embodiment.

FIG. 5 is a diagram showing a partial configuration of an inkjet head driving device according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a partial configuration of a driving device of an inkjet head according to a third embodiment of the present invention.

FIG. 7 is a partial cross-sectional view of an inkjet head according to a fourth embodiment of the present invention.

FIG. 8 is a partial cross-sectional view of a conventional inkjet head.

FIG. 9 is a partial longitudinal sectional view of the conventional inkjet head.

FIG. 10 is a diagram showing a partial configuration of a conventional inkjet head driving device using one power supply.

FIG. 11 is a diagram showing a partial configuration of a conventional inkjet head driving device using two power supplies.

[Explanation of symbols]

 21, 22: Piezoelectric member (electromechanical conversion member) 24: Individual electrode 26: Top plate 27: Orifice plate 28: Ink ejection port 29: Common electrode 37a, 37b, 37c: NPN transistor

Claims (2)

[Claims] A plurality of ink chambers separated by a partition made of a polarized electromechanical conversion member and provided with an ink discharge port at one end, and extending from a partition wall surface of each ink chamber to a surface orthogonal to the partition wall surface. An individual electrode for generating an electric field in a direction perpendicular to the polarization direction of the partition wall between the adjacent ink chambers, and an individual electrode extending on a surface orthogonal to the partition wall surface of each ink chamber. A common electrode disposed at a predetermined interval with respect to the unit, and switching elements respectively connected to the individual electrodes of the ink chambers, and selectively turning on and off the switching elements to form an ink. A drive voltage is applied between the individual electrode of the ink chamber to be ejected and the common electrode, whereby the individual electrode of the ink chamber to be ejected and the individual electrode of the ink chamber adjacent to the ink chamber to be ejected. A driving device for an ink-jet head, wherein a predetermined level of potential difference is applied to reduce the volume of an ink chamber in which ink is to be ejected so that ink is ejected. 2. A plurality of ink chambers separated by a partition made of a polarized electromechanical conversion member and provided with an ink discharge port at one end, and extending from the partition wall surface of each ink chamber to a surface orthogonal to the partition wall surface. An individual electrode for generating an electric field in a direction perpendicular to the polarization direction of the partition wall between the adjacent ink chambers, and an individual electrode extending on a surface orthogonal to the partition wall surface of each ink chamber. A common electrode disposed at a predetermined interval with respect to the unit, a plurality of first switching elements respectively connected between the individual electrode of each ink chamber and a positive potential terminal, and an individual electrode of each ink chamber. A plurality of second switching elements respectively connected between the negative potential terminals, and the first switching element connected to the individual electrode of the ink chamber to which ink is to be ejected is turned on with the common electrode at the ground potential. Do A second switching element connected to an individual electrode of an ink chamber to which ink is to be ejected, and a first switching element connected to an individual electrode of an ink chamber adjacent to the ink chamber to which ink is to be ejected. A second switching element connected to an individual electrode of the ink chamber to discharge ink while the common electrode is at a ground potential by turning off the switching element of No. 2 to increase the volume of the ink chamber to discharge ink. A second element connected to an individual electrode of an ink chamber for discharging ink while turning off the element.
Ink chamber for discharging ink by turning on the first switching element and turning off the first and second switching elements connected to the individual electrodes of the ink chamber adjacent to the ink chamber for discharging ink An ink jet head driving device, characterized in that the volume of the ink is reduced and ink is ejected.