JPH0776084A - Driving method of ink jet device - Google Patents

Abstract

PURPOSE:To reduce driver circuits and patterns to a large extent to relax cross talk and to eliminate the generation of an accidental drop or the mixing with air bubbles. CONSTITUTION:When the injection of ink from the odd number-th ink chamber 4a1 of an A-group is not performed, a brake pulse is applied to an ink chamber 4b1 in the same first timing as a drive pulse. Therefore, the potential difference on both sides of a partition wall 6a1 is kept zero and the partition wall 6a1 is not deformed and no ink is emitted from an ink chamber 4a1. At this time, potential difference is generated in a partition wall 6b1 and the partition wall 6b1 is deformed toward the interior of an ink chamber 4c1 but, since no drive pulse is yet applied to the even number-th ink chamber 4a2, the partition wall 6c1 is not yet deformed and the generation of an accidental drop from the ink chamber 4c1 is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of driving an ink jet device.

[0002]

2. Description of the Related Art Among the non-impact type printers, which have been expanding the market to replace the impact type printers used up to now, the principle is the simplest, and multi-gradation and colorization are possible. Inkjet type printers are mentioned as being easy to use. Above all, a drop that ejects only the ink drops used for printing
The on-demand type is rapidly spreading due to its good injection efficiency and low running cost.

The Kaiser type disclosed in Japanese Patent Publication No. 53-12138 as a drop-on-demand type,
Alternatively, a thermal jet type disclosed in Japanese Patent Publication No. 61-59914 is a typical method.
Of these, the former is difficult to miniaturize, and the latter requires a high heat resistance of the ink in order to apply high heat to the ink, and each has a very difficult problem.

A method proposed to solve the above-mentioned defects at the same time is Japanese Patent Laid-Open No. 252750/1988.
It is the shear mode type disclosed in the publication.

As shown in FIG. 5, the shear mode type ink jet device 1 is composed of a piezoelectric ceramic plate 2, a cover plate 10, a nozzle plate 14 and a substrate 41.

The piezoelectric ceramic plate 2 has a plurality of grooves 3 cut by a diamond blade or the like.
Are formed. In addition, the partition wall 6 that becomes the side surface of the groove 3 is formed.
Is polarized in the direction of arrow 5. The grooves 3 are of the same depth and are parallel. Further, the depths of the grooves 3 gradually become shallower as they approach the one end face 15 of the piezoelectric ceramic plate 2, and a shallow groove 7 is formed near the one end face 15. Then, on the inner surface of the groove 3, metal electrodes 8 are formed by sputtering or the like on the upper halves of both side surfaces thereof. Further, on the inner surface of the shallow groove 7, a metal electrode 9 is formed on the side surface and the bottom surface by sputtering or the like. As a result, the metal electrodes 8 formed on both side surfaces of the groove 3 are electrically connected by the metal electrodes 9 formed in the shallow groove 7.

Next, the cover plate 10 is made of a ceramic material, a resin material, or the like. The cover plate 10 has an ink inlet 16 and a manifold 18 formed by grinding or cutting. Then, the surface of the piezoelectric ceramic plate 2 on the side where the groove 3 is processed and the surface of the cover plate 10 on the side where the manifold 18 is processed are adhered by an epoxy adhesive 20 (see FIG. 7). Therefore, the ink ejecting apparatus 1 is configured with the ink chambers 4 (see FIG. 7) that are the plurality of ink flow paths that are covered with the upper surfaces of the grooves 3 and have the same intervals in the lateral direction. As shown in FIG. 7, the ink chamber 4 has an elongated shape with a rectangular cross section, and ink is filled in all the ink chambers 4.

As shown in FIG. 5, the ink chambers 4 are formed on the end faces of the piezoelectric ceramic plate 2 and the cover plate 10.
The nozzle plate 14 provided with the nozzle 12 is adhered to a position corresponding to the position. This nozzle plate 14
Is formed of a plastic such as polyalkylene (for example, ethylene), terephthalate, polyimide, polyetherimide, polyetherketone, polyethersulfone, polycarbonate, and cellulose acetate.

A substrate 41 is adhered to the surface of the piezoelectric ceramic plate 2 opposite to the processed side of the groove 3 with an epoxy adhesive or the like. Its substrate 41
A conductive layer pattern 42 is formed at a position corresponding to the position of each ink chamber 4. The conductive layer pattern 42
And the metal electrode 9 on the bottom surface of the shallow groove 7 are connected by a conductive wire 43 by known wire bonding.

Next, the configuration of the control unit will be described with reference to FIG. 6 which is a block diagram of the control unit. The conductive layer patterns 42 formed on the substrate 41 are individually connected to the LSI chip 51. The clock line 52, the data line 53, the voltage line 54, and the ground line 55 are also LS.
It is connected to the I-chip 51. The LSI chip 51 is
Based on the continuous clock pulse supplied from the clock line 52, it is determined from which nozzle 12 the ink droplet should be ejected according to the data appearing on the data line 53. Then, the voltage line 5 is formed on the pattern 42 of the conductive layer that is electrically connected to the metal electrode 8 in the driven ink chamber 4.
The voltage V of 4 is applied. Further, the voltage 0V of the earth line 55 is applied to the pattern 42 of the conductive layer which is electrically connected to the metal electrode 8 other than the driven ink chamber 4.

Next, the operation of the ink ejecting apparatus 1 will be described with reference to FIG. The state of each partition wall 6 before the drive voltage is applied is shown in FIG. The LSI chip 51 is configured to, for example, use the ink chamber 4 of the ink ejecting apparatus 1 according to required data.
It is determined that ink is to be ejected from c. Then, the positive drive voltage V is applied to the ink chamber 4c, that is, to the metal electrodes 8d and 8e, and the metal electrodes 8c and 8f are grounded. As shown in FIG. 7B, the partition wall 6b has an arrow 13b.
A drive electric field in the direction of arrow 13c is generated in the partition wall 6c. Then, the driving electric field direction 13
Since b and 13c are orthogonal to the polarization direction 5, the partition walls 6b and 6c are rapidly deformed in the inward direction of the ink chamber 4c due to the piezoelectric thickness sliding effect. Due to this deformation, the volume of the ink chamber 4c is reduced, the ink pressure is rapidly increased, a pressure wave is generated, and an ink droplet is ejected from the nozzle 12 (see FIG. 5) communicating with the ink chamber 4c.

When the application of the driving voltage V is stopped,
Since the partitions 6b and 6c return to the positions before deformation (see FIG. 7A), the ink pressure in the ink chamber 4c gradually decreases. Then, ink is supplied from an ink tank (not shown) into the ink chamber 4c through the ink supply port 16 (FIG. 5) and the manifold 18 (FIG. 5).

In order to improve the efficiency of ink ejection, normally, the polarization 5 is made opposite to each other as shown by an arrow 71 in FIG. 9 and a positive voltage is applied, so that the partitions 6b and 6c are first separated from each other. The partition walls 6b and 6c are returned to the positions before the deformation by ejecting ink droplets by deforming them apart and then stopping the application of voltage.

Here, referring to the timing chart of FIG. 8 and the sectional view of the ink ejecting apparatus of FIG. 9, regarding the behavior of the pressure wave at the time of ink ejection in each ink chamber 4 when the above-described driving method is used. While explaining concretely.

First, in order to eject ink from the ink chamber 4c of FIG. 9B, the ink chamber 4c of FIG.
An ejection voltage pulse C shown in (a) is applied (here, applying a voltage to a certain ink chamber 4 means applying a voltage to the electrode 8 facing the ink chamber 4). Then, at the first rising, the partitions 6b and 6c move away from each other (see FIG. 9B). The volume of the ink chamber 4c increases, and the pressure inside the ink chamber 4c including the vicinity of the nozzle 12 decreases (FIG. 8B). This state is L / in FIG.
It is maintained only during the period indicated by a. Then, ink is supplied from the manifold 18 (FIG. 5) during that time.

The above L / a is the time required for the pressure wave in the ink chamber 4 to propagate one way in the longitudinal direction of the ink chamber 4 (from the manifold 18 to the nozzle plate 14 or vice versa). , The length L of the ink chamber 4 and the speed of sound a in the ink. According to the theory of pressure wave propagation, the pressure in the ink chamber 4c reverses and rises to a positive pressure when the time of L / a rises just after the rise.
At this timing, the voltage applied to the ink chamber 4c is returned to 0V (FIG. 8A). Then, the partition wall 6b
6c returns to the state before deformation (FIG. 9A), and pressure is applied to the ink. At that time, the positively turned pressure and the partition walls 6b and 6c return to the state before the deformation, and the generated pressure is added, so that a relatively high pressure Pc as shown in FIG. 8B is generated in the ink chamber 4c. The ink is ejected from the nozzle 12 by being applied to the ink.

When the image information is formed on the storage medium by using the ink ejecting apparatus 1 having the above-described structure, it is obviously impossible to eject ink simultaneously from at least the adjacent ink chambers 4. Therefore, for example, as described in JP-A-2-150355, a method is used in which the ink chambers 4 are divided into two groups of an odd number and an even number and are alternately ejected. Further, in the case where the above-mentioned Japanese Laid-Open Patent Application uses such a method, when mutual interference between the ink chambers 4, so-called crosstalk, is large, as a method of improving it, three or more groups (for example, when there are three groups) that cross the ink chambers with each other are used. , The ink chamber 4 in FIG.
a and 4d, ink chambers 4b and 4e, and ink chambers 4c and 4
It is proposed that each ink chamber 4 be driven by applying a drive voltage to each of the ink chambers 4 by sequentially rotating them by dividing them into f).

Next, a case in which the ink chamber 4 is divided into three groups that cross each other and sequentially rotated and driven will be described with reference to FIGS. 10 and 11. In FIG. 11, the ink chambers 4a1 and 4a2 are grouped into A, the ink chambers 4b1 and 4b2 are grouped into B, and the ink chambers 4c0, 4c1 and 4c2 are grouped into C in FIG. Note that FIG. 11 shows the ink chamber 4 in order to simplify notation and description.
The electrodes, adhesive layers, etc. were omitted to limit the number of cells.

FIG. 10 is a timing chart showing drive voltage waveforms. The waveforms in (a), (b), (c) and (d) are drive voltages applied to the ink chambers 4a1, 4b1, 4c1 and 4a2, respectively. It is a waveform. FIG. 11 shows the deformation of each partition wall 6 when such a drive voltage waveform is applied to each ink chamber 4. First, the ink chambers 4a1 and 4a
In order to eject the ink from 2, the respective ink chambers 4a
Voltage pulses Va1 and Va2 are simultaneously applied to 1, 4a2. Then, each partition wall 6 is displaced as shown in FIG.
Due to the above displacement, the ink chambers 4a1 and 4a2 of the A group are
Negative pressure is generated. Such displacement is maintained only during the time t1 to t2, that is, during the above L / a. Then, at time t2, the negative pressure wave generated in the ink chambers 4a1 and 4a2 reverses to positive pressure by the pressure propagation theory. In accordance with this, voltage pulses Va1 and Va2
Falls, and each of the deformed partition walls 6 returns to the shape before deformation (FIG. 11A).

By this operation, the ink chambers 4a1 and 4a
The volume of 2 is reduced and a positive pressure is created. The positive pressure is combined with the negative pressure to positive pressure, and becomes a large positive pressure, and the ink in the ink chambers 4a1 and 4a2 is pushed out from the nozzle.

It should be noted that the above voltage pulse may not be applied to the ink chamber in which ink is not ejected, depending on the print pattern. Further, the operations of the groups B and C are explained in exactly the same manner as the group A, but FIG.
(C) shows a deformed state of the partition wall 6 when a drive voltage waveform is applied to the B group.

[0022]

However, when the above driving method is used as it is, all the ink chambers are ejected in order to eject the ink corresponding to the print pattern, although the driving is divided into three groups. The drive voltages to be applied to all four must be applied independently, the same number of drive circuits as the number of ink chambers 4 is required, and the same number of patterns 42 as the number of ink chambers 4 are required.

On the other hand, in the patent application of the same date, the applicant of the present invention applies to each ink chamber of one group when the ink chambers are divided into three or more groups and sequentially rotated to eject the ink. It was proposed to control the ink ejection from all ink chambers by applying all the voltage, but the braking pulse applied to control the ink ejection from the adjacent ink chambers was applied to both partition walls, The same amount of crosstalk as when ejecting the ink in the ink chamber to the adjacent adjacent ink chamber on the opposite side to the control is generated by dividing into two groups according to the conventional technology, causing an accidental drop, mixing air bubbles, etc. There is a problem that there is a fear of.

The present invention has been made in order to solve the above-mentioned problems, and can drastically reduce the number of drive circuits and patterns, alleviate crosstalk, and prevent the occurrence of accidental drops and the inclusion of bubbles. An object of the present invention is to provide a method of driving an ink ejecting apparatus that can be eliminated.

[0025]

In order to achieve this object, according to a first aspect of the present invention, a partition wall at least a part of which is formed by a polarized piezoelectric element, and a plurality of ink chambers separated by the partition wall are provided. And an electrode provided on both sides of the partition wall for generating an electric field that is applied with a voltage and is substantially orthogonal to the polarization direction of the piezoelectric element, and applies a voltage to both electrodes of the ink chamber. In a method of driving an ink ejecting apparatus that deforms a partition wall to generate a pressure wave to eject ink, the plurality of ink chambers are divided into at least three groups of first, second, and third according to ink ejection timing. However, the ejection timings of the adjacent ink chambers in the same group are shifted by an amount smaller than the deviation of the ejection timing between the groups, and the first group or the second group is moved. When ejecting ink from the ink chambers of the first or second group, a voltage is applied to the electrodes of the ink chambers of the first or second group by shifting the displacement amount, and the ink chambers of the first or second group that should not be ejected. , The voltage is applied to the electrodes of the ink chambers of the third group adjacent to the ink chamber, and the ink chambers of the first or second group to be ejected are adjacent to the ink chamber of the third group. By not applying voltage to the electrodes of the ink chambers of the three groups, ink is ejected from the ink chambers corresponding to the print pattern, and when ejecting ink from the ink chambers of the third group, It is characterized in that a voltage is applied to the electrodes of the ink chambers of the three groups to eject the ink.

According to a second aspect of the present invention, the deviation amount of the injection timing in the same group is equal to the application time of the voltage.

According to a third aspect of the present invention, the deviation amount of the ejection timing in the same group is substantially the same as the time for the pressure wave generated in the ink chamber to propagate one way in the longitudinal direction of the ink chamber. .

[0028]

In the method of driving the ink ejecting apparatus of the present invention having the above characteristics, the plurality of ink chambers are divided into at least three groups of first, second and third according to the ink ejection timing, and the same group is formed. When ejecting ink from the ink chambers of the first group or the second group, the ejection timing is shifted with respect to the adjacent ink chambers of the ink chambers by an amount smaller than the deviation of the ejection timing between the groups. , The voltage is applied to the electrodes of the ink chambers of the first or second group while being displaced by the amount of the displacement, so that the pressure fluctuation propagated to the ink chambers of other groups existing between the adjacent ink chambers. Is dispersed, and for the ink chambers of the first or second group that should not be ejected, the third group adjacent to the ink chambers By applying a voltage to the electrode of the ink chamber,
By setting the electric potentials of the electrodes on both sides of the partition that are shared by the ink chambers of the first or second group and the ink chamber of the third group that should not be ejected to the same potential, the partition is not deformed and For the ink chambers of the first or second group, by applying no voltage to the electrodes of the ink chambers of the third group adjacent to the ink chamber, the ink chambers of the first or second group to be ejected on both sides are ejected. When the partition walls are deformed and ink is ejected from the ink chambers corresponding to the print pattern, and when ejecting ink from the ink chambers of the third group, a voltage is applied to the electrodes of the ink chambers of the third group corresponding to the print pattern. When applied, the partition walls of the ink chambers of the third group are deformed and ink is ejected.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same parts as those of the conventional technique are designated by the same reference numerals, and the description thereof will be omitted. Further, the basic structure of the ink ejecting apparatus is the same as that of the conventional technique shown in FIG. 5, but the pattern 42 of the conductive layer formed on the substrate 41 and the connection of the wire bonding for electrical connection to the outside. The method differs from the prior art. The polarization direction is shown in Fig. 5.
The direction of the arrow 71 (FIG. 9) opposite to the arrow 5 of FIG. The basic operation of this embodiment is the same as that of the above-mentioned conventional art.
It is based on a method in which the ink chamber 4 is divided into three groups A, B, and C, which cross each other, and sequentially rotated and driven.

FIG. 1 is a diagram showing a pattern of a conductive layer formed on a head substrate and a connection method of wire bonding according to this embodiment. The substrate 49 has four common conductive layers 4
4, 45, 47, 48 and a plurality of independent conductive layers 46 are patterned. A conductive wire 43 is used to connect the electrode 9 that is electrically connected to the electrode 8 of the partition wall 6 on both sides of each ink chamber 4 and the conductive layer.
Are used, but the connection methods are in the order shown. That is, A
Each of the ink chambers 4 of the group alternates with the common conductive layers 44 and 45.
In addition, the ink chambers 4 of the C group are alternately arranged with the common conductive layer 4
The ink chambers 4 and 7 are connected to the independent conductive layer 46 independently of each other. The ones connected to the common conductive layer 44 are the odd-numbered ink chambers 4 of the A group, and the ones connected to the common conductive layer 45 are the even-numbered ink chambers 4 of the A group. Similarly, for the C group, the ones connected to the common conductive layers 47 and 48 are the odd-numbered and even-numbered ink chambers 4 of the C group, respectively.

The drive voltage waveform of this embodiment and the operation of the injection device when the drive voltage waveform is applied will be described with reference to FIGS. 2, 3 and 4.

FIG. 2 shows a timing chart of the drive voltage applied to the injection device of this embodiment. The voltage waveform Lam shown in FIG. 2A is applied to the common conductive layer 44 that is electrically connected to the odd-numbered ink chambers 4 of the A group, and the voltage waveform Lam shown in FIG.
The voltage waveform Lan in (b) is applied to the common conductive layer 45 that is electrically connected to the even-numbered ink chambers 4 of the A group. These voltage waveforms Lam or Lan are applied to all the ink chambers 4 of the A group regardless of the print pattern.

Similarly, the voltage waveform L of FIGS. 2 (e) and 2 (f)
cm and Lcn are applied to the common conductive layers 47 and 48 that are electrically connected to the odd-numbered and even-numbered ink chambers 4 of the C group. The voltage waveform Lcm or Lcn is applied.

The voltage waveforms Lb1 and Lb of FIGS. 2 (c) and 2 (d)
b2 is applied to the independent conductive layer 46 that is electrically connected to the odd-numbered and even-numbered ink chambers 4 of the B group, and independent voltage waveforms are used for the individual ink chambers 4 of the B group to perform printing. A voltage pulse based on the pattern is applied. Here, the voltage waveform Lb1 is applied to the ink chamber 4b1 (FIG. 3) of the B group, and the voltage waveform Lb2 (FIG. 3) is applied to the ink chamber 4b2.

FIG. 3 shows the movement of the partition wall 6 of each ink chamber 4 when the drive voltage waveforms of FIG. 2 are applied to the ink chamber 4. Here, the operation of ejecting ink will be described with reference to the timing chart of FIG.

First, FIG. 3A shows the state of each partition wall 6 when the drive pulse is not applied to any ink chamber 4. Subsequently, at the first timing, the drive pulse Vam having the voltage waveform Lam is applied to the odd-numbered ink chambers 4 of the group A including the ink chambers 4a1, and the state of each partition wall 6 is changed as shown in FIG.
As shown in (b), both partitions 6c of the ink chamber 4a1
0 and 6a1 are deformed so as to be separated from each other, and this pulse Va
When m is finished, the deformed partition walls 6c0 and 6a1 are
Return to the state before the deformation (FIG. 3C), and the ink chamber 4a1
Ink is ejected from. Here, the width of the drive pulse is
L / a as in the conventional case. Simultaneously with the end of the pulse Vam, that is, after L / a time from the start of the application of the pulse Vam, the drive pulse Van of the voltage waveform Lan is changed to the ink chamber 4a.
Applied to the even-numbered ink chambers 4 of the A group including 2
The state of each partition wall 6 is as shown in FIG. 3C, and both partition walls 6c1 and 6a2 of the ink chamber 4a2 are deformed so as to be separated from each other, and when the pulse Van ends, the above-described deformed partition walls 6c1 and 6a2. Returns to the state before deformation (FIG. 3A), and ink is ejected from the ink chamber 4a2.

Thereafter, at the second timing, the voltage waveform Lb1
Driving pulse Vb1 of the voltage waveform Lb2 is applied to the ink chamber 4b1 at the same time as the end of the pulse Vb1.
b2 is applied to the ink chamber 4b2, and the ink chambers 4b1 and 4b
Ink is ejected from b2 in the same manner as described for the ink chambers 4a1 and 4a2. At the next third timing, the drive pulse Vcm of the voltage waveform Lcm changes to the ink chamber 4c1.
Is applied to the voltage waveform L at the same time as the end of the pulse Vcm.
The drive pulse Vcn of cn is applied to the ink chamber 4c2,
Ink is ejected in the same manner as above.

In the above, an example in which ink is ejected from the ink chambers 4 of each of A, B, and C groups in order has been described, but next, ink is ejected from only a specific ink chamber 4 based on a print pattern. The driving method to be performed will be described with reference to FIG. In this embodiment, all the ink chambers 4 of the A group and the C group are connected to the common conductive layers 44, 45 and 47, 48, respectively. It is not possible not to apply a drive pulse to. Therefore, for example, even when the ink ejection from the ink chamber 4a1 of FIG. 3 is not performed, the drive pulse Vam having the voltage waveform Lam is applied at the first timing.

In this embodiment, the braking pulse Vbam is applied to the ink chamber 4b1 at the same first timing as the drive pulse Vam so that the ink is not ejected from the ink chamber 4a1. By applying the braking pulse Vbam, the potential difference on both sides of the partition wall 6a1 is maintained at 0, and the partition wall 6a1 is braked and is not deformed as shown in FIG. 4B.

Therefore, the pressure generated in the ink chamber 4a1 is only due to the partition wall 6c0, the pressure in the ink chamber 4a1 is only half of the pressure at the time of normal ink ejection, and ink is not ejected. At this time, a potential difference is generated in the partition wall 6b1,
The partition 6b1 is deformed into the ink chamber 4c1.
Since c1 has not been deformed yet, the generation of accidental from the ink chamber 4c1 is suppressed.

With the same principle, the braking pulse Vban can be used to control the deformation of the partition wall 6a2 and control the ejection of ink from the ink chamber 4a2 (FIG. 4 (c)). Ink ejection in the ink chamber 4 of the C group can be performed in the same manner as in the A group. Further, the ink ejection in the ink chambers 4b1 and 4b2 of the B group can be controlled in the same manner as in the conventional case depending on whether the drive pulse Vb1 or Vb2 is applied. Since each ink chamber 4 of the B group is connected to the independent conductive layer 46, an independent voltage waveform Lb can be applied to each ink chamber 4. Therefore, in the ink ejecting apparatus of this embodiment, ink ejection from all the ink chambers 4 can be controlled.

As described above, according to the driving method of the ink ejecting apparatus of the present embodiment, the first timing, the L / a of the first timing, and the third timing are set in all the ink chambers 4 of the A group and the C group. L / a of timing and third timing
After that, drive pulses Vam, Van, Vcm and Vcn are applied, and braking pulses Vbam, Vban, Vbcm and Vbcn and B group for controlling ejection from the ink chambers 4 of the A group and C group are applied to the ink chambers 4 of the B group. Drive pulses Vb1 and V ejected from the ink chamber 4 of
Since b2 is applied, the ink chambers 4 of the A group and the C group are electrically connected to the common conductive layers 44, 45, 47, and 48, and the ink chambers 4 of the B group are connected to the independent conductive layers 46, respectively. . Therefore, the number of drive circuits for applying the drive pulse and the braking pulse to the ink chambers 4 of the B group is as many as the number of the ink chambers 4 of the B group, but the drive pulse is applied to all the ink chambers 4 of the A group and the C group. There are two drive circuits to apply
Two for a group.

Therefore, the number of independent control signals for printing an arbitrary print pattern is only 1/3 + 4 of the number of all ink chambers 4 of the ink ejecting apparatus 1, and the number of independent drive circuits is increased. It can be reduced to 1/3 + 4 of the conventional technique, and the drive circuit can be downsized and the cost can be reduced. Also,
The number of electrical contacts between the drive circuit and the ink ejecting apparatus 1 can be reduced to 1/3 + 4 of the conventional technique, and the number of troubles such as electrical connection failure and short circuit can be reduced, and reliability is improved. To be done. Furthermore, the substrate 49 of the injection device
The number of conductive layers formed above can be reduced to 1/3 + 4 of the conventional technique, and the processing cost can be reduced in the process of forming the conductive layer pattern.

As described above, when the number of drive circuits is reduced, especially in the case of a line head in which the ink chambers are arranged in a line in the paper width, several thousand ink chambers are provided. Is very effective.

Further, in the present embodiment, since the ejection timings of the odd-numbered ink chambers 4 and the even-numbered ink chambers 4 of the same group are displaced by L / a, the braking pulse Vbam is generated.
Is applied to the ink chamber 4b1, the ink chamber 4a2
Is not applied with the drive pulse Van. For this reason,
At this time, only the pressure due to the deformation of the partition wall 6b1 is generated in the ink chamber 4c1. Also, L / of the first timing
After “a”, the partition wall 6b1 returns to its original state, and the drive pulse Van is applied to the ink chamber 4a2 to cause the ink chamber 4a2 to move.
Only pressure due to the deformation of the partition wall 6c1 for ejecting ink from the ink chamber 4a2 is applied to c1. Therefore,
The pressure in the ink chamber 4c1 is L / due to the partition wall 6 on one side.
The ink is not ejected because it is given with a deviation. Therefore, it is possible to prevent the occurrence of crosstalk in the ink chamber 4c1 which is almost the same as in the case of ejecting the ink into the two groups of the related art, to generate an accidental drop from the ink chamber 4c1 and to mix air bubbles into the ink chamber 4c1. Is prevented.

Although a simple rectangular pulse is used as the driving pulse for ejecting ink in the above-mentioned embodiment, a driving pulse other than the simple rectangular pulse may be used. As another embodiment of the present invention, for example, a drive pulse that swings both positive and negative may be used. In this case, if the drive pulse and the braking pulse have the same waveform and the timing is correct, the partition wall 6 to be braked is not deformed. Therefore, the ejection of ink can be controlled as in the above embodiment.

The shape of the braking pulse does not necessarily have to be the same as that of the driving pulse. In this case, although the partition wall 6 to be braked is not always completely deformed, the shape of the braking pulse does not matter as long as the ink is not ejected when the braking pulse is applied.

Further, the application timing of the braking pulse does not necessarily have to coincide with the drive pulse. In this case, the partition wall 6 to be braked is not always completely deformed, but the braking pulse application timing does not matter as long as the ink is not ejected when the braking pulse is applied.

Further, by using the braking pulse set by the most suitable combination of the shape of the braking pulse and the application timing of the braking pulse, the control for ink ejection can be optimized.

Further, although the ink chamber 4 is divided into three groups in this embodiment, it may be divided into three or more groups. For example, in the case of four groups A, B, C, and D, groups A and C are connected to a common conductive layer, and groups B and D are connected to independent conductive layers for driving. Also,
For the five groups A, B, C, D, E, A,
The C and D groups are connected to a common conductive layer, and the B and E groups are connected to independent conductive layers for driving.

[0051]

According to the ink jet device using the driving device and the driving method of the present invention, the number of independent control signals for printing an arbitrary printing pattern is smaller than the number of all ink chambers and independent. The number of drive circuits can be reduced as compared with the prior art, and the drive circuits can be downsized and the cost can be reduced. Also, the number of electrical contacts between the drive circuit and the injection device can be reduced as compared with the conventional technique, the number of occurrences of troubles such as electrical connection failure and short circuit can be reduced, and reliability can be improved. Further, the number of conductive layers formed on the substrate of the ejector can be reduced as compared with the prior art,
In the process of forming the conductive layer pattern, the processing cost can be reduced. Further, since the ejection timings of the adjacent ink chambers in the same group of ink chambers are shifted by an amount smaller than the deviation of the ejection timings of the respective groups, the ink chambers of the first or second group of the third group When controlling the ink ejection from the ink chambers, the pressure to the ink chambers that should not be ejected is dispersed, and the occurrence of crosstalk, which is almost the same as in the case of ejecting ink in two groups of the related art, is eliminated. It is possible to prevent the occurrence of accidental drops and the inclusion of air bubbles.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing electrical connection of an injection device according to an embodiment of the present invention.

FIG. 2 is a timing chart showing a waveform of a voltage applied to the injection device according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an operation of the ink ejecting apparatus according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing an operation of the ink ejecting apparatus according to the embodiment of the present invention.

FIG. 5 is a perspective view showing a conventional shear mode type ink jet device.

FIG. 6 is an explanatory diagram showing a conventional control unit.

FIG. 7 is an explanatory diagram showing an operation of a conventional shear mode type ink jet device.

FIG. 8 is a timing chart showing another voltage waveform of the conventional ink ejecting apparatus.

FIG. 9 is an explanatory diagram showing another operation of the conventional ink ejecting apparatus.

FIG. 10 is a timing chart showing voltage waveforms when ink chambers of a conventional ink ejecting apparatus are divided into three groups. It is explanatory drawing which shows operation.

FIG. 11 is an explanatory diagram showing an operation when the ink chambers of the conventional ink ejecting apparatus are divided into three groups.

[Explanation of symbols]

 1 Ink Ejector 2 Piezoelectric Ceramic Plate 4 Ink Chamber 6 Partition 8 Electrode 9 Electrode 44 Common Conductive Layer 45 Common Conductive Layer 46 Independent Conductive Layer 47 Common Conductive Layer 48 Common Conductive Layer 71 Polarization Direction

Claims (3)

[Claims] 1. A partition wall, at least a part of which is formed by a polarized piezoelectric element, a plurality of ink chambers separated by the partition wall, and an electric field which is applied with a voltage and is substantially orthogonal to the polarization direction of the piezoelectric element. An ink ejecting device that has electrodes provided on both sides of the partition wall for generating the ink, and applies a voltage to both electrodes of the ink chamber to deform both partition walls to generate a pressure wave and eject ink. In the driving method, the plurality of ink chambers are divided into at least three groups of first, second, and third groups according to ink ejection timing, and ink is ejected to adjacent ink chambers in the same group of ink chambers. When the timing is shifted by an amount smaller than the deviation of the ejection timing between the groups, and when ejecting ink from the ink chambers of the first group or the second group, In addition to applying a voltage to the electrodes of the ink chambers of the first group by shifting the displacement amount, and for the ink chambers of the first or second group that should not be ejected, the inks of the third group adjacent to the ink chambers are applied. For the ink chambers of the first or second group to be ejected by applying a voltage to the electrodes of the chambers, the voltage is not applied to the electrodes of the ink chambers of the third group adjacent to the ink chambers, so that the printing pattern When the ink is ejected from the ink chamber corresponding to, and the ink is ejected from the ink chamber of the third group, a voltage is applied to the electrode of the ink chamber of the third group corresponding to the print pattern to eject the ink. A method for driving an ink ejecting apparatus, comprising: 2. The method of driving an ink ejecting apparatus according to claim 1, wherein the deviation amount of the ejection timing in the same group is equal to the application time of the voltage. 3. The deviation amount of the ejection timing in the same group is substantially the same as the time for one-way propagation of the pressure wave generated in the ink chamber in the longitudinal direction of the ink chamber. A method for driving an ink ejection device as described above.