JPH0929964A - Driving method of ink jet device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the driving method of a low cost ink jet device having favorable printing quality, in which the volume of ink drop is changed in response to resolution and the change of ink jetting speed due to driving frequency is small. SOLUTION: Driving waveform 10 used in 360dpi has first pulse signal A, the width Wa of which is 3 times as much as the one-way propagation time T of pressure wave in ink flow passage. Printing, the jetting of ink drop at which of about 40pl, is performed by employing the driving waveform 10. Driving waveform 20 used in 720dpi has pulse signal C for jetting ink and the same crest value as that of the pulse signal A under the condition that the width Wc of the pulse signal C is 0.625 times as much as the one-way propagation time T. Printing, the jetting of ink drop at which of about 25pl, is performed by employing the driving waveform 20. Respective favorable printing qualities are obtained by employing driving frequencies of 360 and 720dpi.

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 The non-impact type printing apparatus which has been replacing the conventional impact type printing apparatus and is now expanding its market greatly is the simplest in principle and has a multi-gradation and color printing. An easy-to-use printing apparatus is an ink jet printing apparatus. 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 defects at the same time is disclosed in Japanese Patent Laid-Open No. 63-247051.
This utilizes the shear mode deformation of the piezoelectric ceramics disclosed in the publication.

As shown in FIG. 6, the shear mode type ink jet device 600 comprises a bottom wall 601, a ceiling wall 602 and a shear mode actuator wall 603 therebetween. The actuator wall 603 is bonded to the bottom wall 601 and is polarized in the direction of arrow 611.
And an upper wall 605 bonded to the ceiling wall 602 and polarized in the direction of arrow 609. The actuator walls 603 are paired to form an ink flow path 613 therebetween, and a space 615 narrower than the ink flow path 613 is formed between the next pair of actuator walls 603.

The nozzle 6 is provided at one end of each ink flow path 613.
A nozzle plate 617 having 18 is fixed, and electrodes 619 and 621 are provided as metal layers on both side surfaces of each actuator wall 603. Each electrode 619, 621 is covered with an insulating layer (not shown) for insulating the ink. The electrode 621 facing the space 615 is connected to the ground 623, and the electrode 619 provided in the ink flow path 613 is connected to the silicon chip 625 which gives an actuator drive signal.

Next, a method of manufacturing the ink ejecting apparatus 600 will be described. First, the piezoelectric ceramic layer polarized in the arrow 611 is bonded to the bottom wall 601, and the piezoelectric ceramic layer polarized in the arrow 609 is bonded to the ceiling wall 602. The thickness of each piezoelectric ceramic layer is equal to the height of the lower wall 607 and the upper wall 605. Next, parallel grooves are formed in the piezoelectric ceramics layer by rotating a diamond cutting disk or the like to form a lower wall 607 and an upper wall 605. The electrode 61 is formed on the side surface of the lower wall 607 by vacuum deposition.
9, 621 are formed, and the insulating layer is provided on the electrodes 619, 621. Similarly, electrodes 619 and 621 and the insulating layer are provided on the side surface of the upper wall 605.

The zenith of the upper wall 605 and the zenith of the lower wall 607 are adhered to each other to form an ink flow path 613 and a space 615. Next, a nozzle plate 617 on which the nozzles 618 are formed is adhered to one end of the ink flow passage 613 and the space 615 so that the nozzles 618 correspond to the ink flow passages 613, and the ink flow passages 613 and the space 615 are connected. The other end is electrically connected to silicon chip 625 and ground 623.

Then, the electrode 619 of each ink flow path 613
By applying a voltage to the recon chip 625, each actuator wall 603 undergoes piezoelectric thickness slip deformation in the direction of increasing the volume of the ink flow path 613. For example, as shown in FIG. 7, when a voltage V is applied to the ink flow path 613c, electric fields in the directions of arrows 627 and 629 are generated in the actuator walls 603e and 603f, and the actuator walls 603d and 603e cause the volume of the ink flow path 613c to change. The piezoelectric thickness undergoes slip deformation in the direction of increasing. At this time, the pressure in the ink flow path 613c including the vicinity of the nozzle 618c decreases. This state is maintained for the time T of one-way propagation of the pressure wave in the ink flow path 613. Then, ink is supplied from a manifold (not shown) during that time. The one-way propagation time T is the time required for the pressure wave in the ink flow path 613 to propagate in the longitudinal direction of the ink flow path 613, and the length L of the ink flow path 613 and this ink flow path 613.
T = L / a is determined by the sound velocity a in the ink inside. According to the theory of pressure wave propagation, the pressure in the ink flow path 613 reverses and changes to a positive pressure just after a lapse of T time from the application of the above voltage, but the electrode 619c of the ink flow path 613c coincides with this timing. The voltage applied to is reset to zero.

Then, the actuator walls 603e, 60
3f returns to the state before deformation (FIG. 6), and pressure is applied to the ink. At that time, the positive pressure and the pressure generated by the actuator walls 603e and 603f returning to the state before the deformation are added, and a relatively high pressure is generated in a portion of the ink flow path 613c near the nozzle 618c. Ink is ejected from the nozzle 618c.

After the ink is ejected, if the ink flow path 6
Unless a new voltage pulse is applied to the electrodes 619e and 619f of 13c, the pressure in the ink flow path 613c is 2
It keeps changing for a while with T as a cycle. This is the residual pressure fluctuation. Due to this residual pressure fluctuation, when the frequency of the voltage pulse is changed, the ink ejection speed fluctuates, and the landing position shifts, which impairs print quality and makes ejection impossible.

On the other hand, for example, JP-A-62-2993
As disclosed in Japanese Laid-Open Patent Publication No. 43-43, it is considered to reduce the residual pressure fluctuation in the ink flow path 613 by applying a cancel pulse after the print pulse for ejecting ink. That is, a cancel pulse for generating a pressure wave having a phase opposite to the residual pressure fluctuation in the ink flow path 613 is applied after a fixed time from the ink ejection. As shown in FIG. 8, the ink flow path 6
A cancel pulse G having a width T and a phase opposite to that of the ejection pulse is applied to the 13 electrode 619 after T from the trailing edge of the ejection pulse F. The voltage value is set according to the amplitude of the residual pressure fluctuation so that the fluctuation is just canceled (for example, 0.6 times the injection pulse). By applying this cancel pulse, the actuator wall 603 is deformed in the opposite manner to that at the time of ink ejection, and a pressure wave having a phase opposite to the residual pressure fluctuation is applied to cancel the residual pressure fluctuation. As a result, fluctuations in the ink ejection speed when the frequency of the voltage pulse is changed are eliminated, and printing quality is improved.

Next, a drive circuit for realizing the cancellation of the residual pressure fluctuation will be described. The output signals X, Y, and Z shown in FIG.
Is a signal for setting the voltage to be applied to V, 0, −0.6 × V. When the output signal X is turned on, a voltage pulse (F in FIG. 8) for ejecting ink is generated. Also,
When the output signal Z is turned on, a voltage pulse (G in FIG. 8) for causing a pressure fluctuation for cancellation is generated.
In other cases than the above, the output signal Y is turned on and the output voltage is set to zero. The capacitor 91 includes the actuator wall 603 of the ink flow path 613 and the electrodes 6 formed on both sides thereof.
15, 619.

The drive circuit is composed of three blocks surrounded by a broken line, and each of them is an injection charging circuit 82, a discharging circuit 84 and a canceling pressure generating circuit 86.
When the input signal X turns on, the transistor Tc
Becomes conductive, and a voltage of V is applied from the positive power source 87 to the electrode E of the capacitor 91 via the resistor R12. Input signal Y
Is turned on, the transistor Tg is turned on, and the resistor R1
The electrode E of the condenser 91 is grounded via 2. When the input signal Z is turned on, the transistor Ts becomes conductive, and the negative power source 88 applies a voltage of −0.6 × V to the electrode E of the capacitor 91 via the resistor R12.

Further, as shown in FIG. 10, the width T is the same as the phase of the injection pulse 2T 2T after the fall of the injection pulse F, and the voltage value corresponding to the amplitude of the residual pressure fluctuation (for example, 0.5 of the injection pulse). It is also possible to cancel the residual pressure fluctuation by applying a cancellation pulse H of 2 times. The drive circuit in this case does not require the negative power source 88 as shown in FIG. 9, but the voltage V × 0.
Prepare a second positive power source (not shown) that generates 5
It may be used while switching to the positive power source 87.

Here, when the print density is changed, for example, when the print density is lowered, it is necessary to increase the ink droplet volume in order to maintain the print quality. A method of increasing the driving voltage and increasing the volume of the ink droplet is disclosed in Japanese Patent Laid-Open No. 62-1 / 1987.
It is disclosed in Japanese Patent Publication No. 99450.

[0017]

However, in the method of driving the ink ejecting apparatus having the above-mentioned configuration, when the volume of the ink droplet is increased, the drive voltage is increased, so that two or more kinds of power supplies having different voltage values are required. Therefore, there is a problem that the cost increases. Further, Japanese Patent Laid-Open No. 62-199450 discloses changing the ink drop volume by changing the voltage width, but the specific width is not disclosed.

In order to suppress the residual pressure oscillation, the pressure wave propagates in the ink flow path 613 after the ejection pulse F having a positive voltage V is applied, and the pressure wave propagates back and forth once, or after one and a half cycles back and forth. In order to cancel the fluctuation, it is necessary to give a cancel pulse G having a negative voltage or a cancel pulse H having a positive voltage but different voltage values. For this reason, a positive power source and a negative power source, or two types of positive power sources with different voltages are required, which complicates the drive circuit,
There was a problem that the cost would go up.

According to the present invention, the ink droplet volume is switched according to the print density with only a single driving power source, and the fluctuation of the ink ejection speed is suppressed when the frequency of the voltage pulse is changed, thereby obtaining a good print quality. It is an object of the present invention to present a low-cost method of driving an ink ejecting apparatus that can be obtained.

[0020]

In order to achieve this object, according to a first aspect of the present invention, an ink chamber filled with ink, an actuator for changing the volume of the ink chamber, and an electric actuator for the actuator are provided. A single drive power source for applying a signal, and a control unit for applying a pulse signal from the single drive power source to the actuator to change the volume of the ink chamber and eject ink droplets. In the driving method of the ink ejecting apparatus, the control means has a first resolution and a pulse width that is three times or more and one-odd times the one-way propagation time T of the pressure wave in the ink chamber. A waveform signal is applied to the actuator from the single drive power supply to eject a first volume of ink droplets at a second resolution that is higher than the first resolution and a pulse width of the first resolution. One-way propagation time T of pressure wave in the ink chamber
A second drive signal having a peak value of 0.6 to 0.9 times or 1.1 to 1.4 times the same as that of the first drive waveform signal to the actuator. Is applied to eject an ink droplet having a second volume smaller than the first volume.

According to a second aspect of the present invention, the first drive waveform signal has a pulse signal A having a pulse width of 3T or more and an odd multiple, and the same crest value as the pulse signal A, and has a pulse width of 0. .3T to 1.7T, and the delay time Td from the falling timing Tp of the pulse signal A to the central timing Tm of the rising timing Ts and the falling timing Te is 2.25T to 2.75T.
And a pulse signal B that is

In the third aspect, the pulse signal B of the first drive waveform signal has a pulse width of 0.5T or 1.3T.
It is characterized in that it is 1.7T and the delay time Td is 2.5.

In the present invention, the second drive waveform signal has a pulse width of 0.6T to 0.9T or 1.1T.
The pulse signal C of 1.4T has the same peak value as that of the pulse signal C and the pulse width of 0.3T to 1.7T.
And the delay time Td from the falling timing Tp of the pulse signal C to the central timing Tm of the rising timing Ts and the falling timing Te.
Of the pulse signal D is 2.25T to 2.75T.

According to a fifth aspect of the present invention, the pulse signal D of the second drive waveform signal has a pulse width of 0.5T or 1.5T and a delay time Td of 2.5.

[0025]

In the method for driving the ink ejecting apparatus according to the present invention having the above-described configuration, the control means causes the control means to have a one-way propagation time T of the pressure wave of the ink chamber having a pulse width at the first resolution.
Is applied to the actuator from the single drive power source to eject an ink droplet of a first volume. Then, at the second resolution which is higher than the first resolution, the control means determines that the pulse width is 0.6 to 0.9 times the one-way propagation time T of the pressure wave in the ink chamber or 1.1 to 1. The second that is four times the same and has the same crest value as the first drive waveform signal
Is applied to the actuator from the single drive power source to eject an ink droplet having a second volume smaller than the first volume. Ink droplets having a volume corresponding to each of the first resolution and the second resolution are ejected.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

The ink ejecting apparatus 600 of this embodiment is shown in FIG.
Like the conventional ink ejecting apparatus 600 shown in FIG.
1, a top wall 602 and a shear mode actuator wall 603 therebetween. The actuator wall 603 is
A lower wall 607 bonded to the bottom wall 601 and polarized in the direction of arrow 611, and a top wall 602, and the arrow 6
The upper wall 605 is polarized in the 09 direction. A pair of actuator walls 603 form an ink flow path 613 therebetween, and a space 61 narrower than the ink flow path 613 is formed between the next pair of actuator walls 603.
5 are formed.

The nozzle 6 is provided at one end of each ink flow path 613.
A nozzle plate 617 having 18 is fixed, and electrodes 619 and 621 are provided as metal layers on both side surfaces of each actuator wall 603. Each electrode 619, 621 is covered with an insulating layer (not shown) for insulating the ink. The electrode 621 facing the space 615 is connected to the ground 623, and the electrode 619 provided in the ink flow path 613 is connected to the silicon chip 625 which gives an actuator drive signal.

An example of specific dimensions of the ink ejecting apparatus of this embodiment will be described. The length L of the ink flow path 613 is 7.5.
mm. The nozzle 618 has a diameter of 40 μm on the ink ejection side, a diameter of 72 μm on the ink flow path 613 side, and a length of 100 μm. The viscosity of the ink used in the experiment is 2 mPa / s and the surface tension is 30 mN / m. The speed of sound in the ink in the ink flow path 613 is a ratio of a to L, L / a (= one-way propagation time T of pressure wave).
Is 8 μsec.

Next, driving waveforms 10 and 20 applied to the electrode 619 in the ink flow path 613 of this embodiment are shown in FIG. The first drive waveform 10 is a waveform for obtaining a first ink drop having a large volume, and the second drive waveform 20 is a waveform for obtaining a second ink drop having a small volume. For example, when the resolution is low. The drive waveform 10 is selected, and when the resolution is high, the drive waveform 20 is selected, so that the volume of the ink droplet suitable for the resolution can be selected.

The first drive waveform 10 is a first pulse signal A for ejecting ink and the ink flow path 6 after ejection.
And a second pulse signal B for compensating the residual pressure fluctuation in 13 and both the first pulse signal A and the second pulse signal B have the same crest value (voltage value) (for example, 22
v). The width Wa of the first pulse signal A coincides with three times the one-way propagation time T (L / a) of the pressure wave in the ink flow path 613, that is, 24 μsec. The width Wb of the second pulse signal B corresponds to 1.5 times the one-way propagation time T of the pressure wave in the ink flow path 613, that is, 12 μsec. Falling timing Tp of the first pulse signal A
From 1 to the rising timing T of the second pulse signal B
The delay time Td1 until the intermediate timing Tm1 between s1 and the falling timing Te1 is the ink flow path 61.
It corresponds to 2.5 times the one-way propagation time T of the pressure wave in 3, ie, 20 μsec.

The second drive waveform 20 has a first pulse signal C for ejecting ink and the ink flow path 6 after ejection.
And a second pulse signal D for compensating the residual pressure fluctuation in 13 and both the first pulse signal C and the second pulse signal D have the same peak value (voltage value) (for example, 22
v). The width Wc of the first pulse signal C is 0 .. of the one-way propagation time T (L / a) of the pressure wave in the ink flow path 613.
625 times, that is, 5 μsec, and the width Wd of the second pulse signal D matches 0.5 times the one-way propagation time T of the pressure wave in the ink flow path 613, that is, 4 μse.
c.

By setting the width Wc of the first pulse signal C to 5 μs which is 0.625 times the one-way propagation time T, the same ink droplet ejection speed as the ink droplet ejection speed by the first drive waveform 10 can be obtained. Can be obtained. The width Wc of the first pulse signal C is changed from 0.6 to 1 of the one-way propagation time T of the pressure wave according to the change of the type of ink, the ink flow path shape, the nozzle shape, and the like.
It may be adjusted to 0.9 times or 1.1 to 1.4 times so as to obtain the same ink droplet ejection speed as the first drive waveform 10. The delay time Td2 from the falling timing Tp2 of the first pulse signal C to the intermediate timing Tm2 between the rising timing Ts2 and the falling timing Te2 of the second pulse signal D is as shown in the first drive waveform 10. It is equal to 2.5 times the one-way propagation time T of the pressure wave that is the same as the delay time Td1, that is, 20 μ
sec.

An embodiment of a drive circuit for realizing the drive waveforms 10 and 20 will be described with reference to FIGS. FIG.
The output signals X and Y shown in are signals for setting the voltages applied to the electrodes 619 in the ink flow path 613 to V and 0, respectively. When the output signal X turns on, the voltage V is generated, and when the output signal Y turns on, the voltage becomes 0. Capacitor 1
91 is composed of an actuator wall 603 of the ink flow path 613 and electrodes 619 and 621 formed on both sides thereof.

The drive circuit is composed of two blocks surrounded by a broken line, and each is a charging circuit 182 for injection and a circuit 184 for discharging. Then, when the input signal X is turned on, the transistor Tc becomes conductive, and a voltage of V, for example, 22v is applied from the positive power source 187 to the electrode E of the capacitor 191 via the resistor R120. When the input signal Y is turned on, the transistor Tg becomes conductive, and the voltage E of the capacitor 191 is grounded via the resistor R120.

The timing charts 11 and 12 of the input signals X and Y of the first drive waveform 10 and the output voltage waveform 13 of the electrode E are shown in FIG. Second drive waveform 20
Timing chart 1 for each input signal X, Y
4 and 15 and the output voltage waveform 16 of the electrode E are shown in FIG.

As shown in the timing chart 11 of the input signal X, the input signal X is normally off, and is turned on at a predetermined timing T1 for injection and turned off at timing T2. Thereafter, it is turned on at timing T3 and turned off at timing T4. The second drive waveform 20 is turned on at timing T5 and turned off at timing T6. Thereafter, it is turned on at timing T7 and turned off at timing T8. The timing chart 12 of the input signal Y is turned off when the input signal X is on, and turned on when the input signal X is off.

Output waveforms 13 and 16 at the electrode E at that time
Is normally 0 V, but the charge to the capacitor 191 is charged at timings T1 and T5, and the charging time T determined by the transistor Tc, the resistor R120, and the capacitor 191.
After a, the voltage becomes V (for example, 22v), and the charges of the capacitor 191 are discharged at timings T2 and T6, and become 0v after a discharge time Tb determined by the transistor Tg, the resistor R120, and the capacitor 191. Subsequently, at timings T3 and T7, the electric charge to the capacitor 191 is charged,
After the charging time Ta determined by the transistor Tc, the resistor R120, and the capacitor 191, the voltage becomes V (for example, 22v). Further, the electric charge of the capacitor 191 is discharged at timings T4 and T8, and becomes 0v after a discharge time Tb determined by the transistor Tg, the resistor R120 and the capacitor 191.

As described above, since the actual drive waveforms 13 and 16 are delayed by Ta and Tb at the rising edge and the falling edge, respectively, the first and second drive waveforms 10 and 20 at the voltage of ½ × V (for example, 11 v) are generated. 1 pulse signal A,
Widths Wa and Wc of C and widths W of the second pulse signals B and D
b, Wd and the delay time Td are set to the values shown in FIG. 1 at the respective timings T1, T2, T3, T4, T5, T.
6, T7 and T8 are set.

An ink jet test was carried out when the device was driven by the driving method of this embodiment described above. The driving voltage was 22 v, at which the ink ejection speed was 5 m / s when the driving frequency was very slow, for example, 60 Hz. When the drive frequency was changed from 5 kHz to 15 kHz, stable ejection was possible with an ink ejection speed of 4.5 to 5.3 m / s for both the first drive waveform 10 and the second drive waveform 20. It was As a comparative experiment, when only the first pulse signal A of the first drive waveform 10 of this embodiment is used for driving, the ink ejection speed varies between 4.5 and 6.5 m / s, and the driving frequency is 8 kHz. In the above case, the injection becomes impossible, and when the driving is performed only by the first pulse signal C of the second driving waveform 20,
The ink ejection speed varied between 4 and 7 m / s, and ejection was impossible at a drive frequency of 6 kHz or higher. The result is shown in FIG. From this result, it is understood that the driving method of the present embodiment suppresses the fluctuation of the ink ejection speed when the frequency of the voltage pulse is changed. Further, the ink droplet volume is about 40 pl when driven by the first drive waveform 10 and is about 25 pl when driven by the second drive waveform 20, regardless of the frequency. Drive waveform 2
The ink droplet volume was increased by about 60% from the case of 0.

If this first drive waveform 10 is used during printing at a resolution of 360 dpi and the second drive waveform 20 is used during printing at a resolution of 720 dpi, for example, good print quality can be obtained at each resolution. be able to.

Further, in the method of driving the ink ejecting apparatus of the present embodiment, the electrode 619 of the ink flow path 613 has the first pulse signal A, the second pulse signal B and the second drive waveform in the first drive waveform 10. Since the same positive voltage V is applied to all of the first pulse signal C and the second pulse signal D in 20, the driving power source is only the positive power source 187. Alternatively, the control circuit becomes simpler and the cost can be reduced as compared with the case of using two types of positive power supplies having different voltages.

Next, the widths Wb and Wd of the second pulse signals B and D in the respective drive waveforms 10 and 20 and the falling timings Tp1 and Tp2 of the first pulse signals A and C.
From the intermediate timing Tm1 of the second pulse signals B and D,
The result of an experiment conducted to find an appropriate range with the delay time Td up to Tm2 will be described.

FIG. 5 shows the width W of the second pulse signals B and D.
b and Wd are changed to 0.3T to 2.0T and the delay time Td is changed to 2.0T to 3.0T. The results for the first drive waveform 10 are shown on the left side, and the results for the second drive waveform 20 are shown on the right side. The evaluation method is from 5 kHz
The drive frequency was changed up to 15 kHz and the change in the ink ejection speed was examined. The driving voltage was a very slow driving frequency, for example, 22 v at which the ink ejection speed was 5 m / s when the driving frequency was 60 Hz.

The double circle evaluated here has a speed fluctuation of 1 m.
/ S is less than 1.0, and the speed fluctuation of the circle is 1.0 or more and 2.0 m /
Less than s, triangle has speed fluctuation of 2.0 or more and less than 3 m / s, ×
Indicates that injection is impossible at a certain frequency. From this result, the delay time Td is in the range of 2.25T to 2.75T, and the widths Wb and Wd of the second pulse signals B and D are set to 0.
When 3T to 1.7T, the speed fluctuation is small, and the width Wb of the second pulse signal B is 0.5T or 1.3 to.
When 1.7T and the width Wd of the second pulse signal D is 0.5T or 1.5T, it is possible to eject ink with better printing quality.

Although one embodiment has been described in detail above, the present invention is not limited to this embodiment. For example, in the above embodiment, the positive power source 187 was used, but the negative power source may be used by reversing the polarization directions of 609 and 611 in FIG. With respect to other configurations, the present invention can be implemented in variously modified and improved modes based on the knowledge of those skilled in the art without departing from the scope of the claims.

In this embodiment, the actuator wall 60
Although the volume of the ink flow path 613 was deformed by the piezoelectric deformation of the lower wall 607 and the upper wall 605 of No. 3 to eject ink, one of the lower wall and the upper wall is formed of a material that does not cause piezoelectric deformation, and the other piezoelectric The ink may be ejected so that the ink is deformed along with the deformation.

Further, in this embodiment, the air chambers 615 are provided on both sides of the ink flow passage 613, but the ink flow passages may be adjacent to each other without providing the air chambers.

[0049]

As described above, according to the driving method of the ink jet apparatus of the present invention, the control means, at the first resolution, sends the first drive waveform signal to the actuator from the single drive power supply. In the second resolution, the control means applies the second drive signal to the actuator from the single drive power source, and the first ink droplet having a volume corresponding to each of the first resolution and the second resolution. , The second ink droplet is ejected, so that the print quality of both the first resolution and the second resolution is good. Furthermore, it can be driven by a single drive power supply, which makes the drive circuit simpler than before,
Lower costs.

[Brief description of drawings]

FIG. 1 is a diagram showing drive waveforms of an ink ejecting apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a drive circuit of the ink ejecting apparatus.

FIG. 3 is a timing chart of a driving method of the ink ejecting apparatus.

FIG. 4 is a diagram showing a result of an experiment in which a frequency of a driving method of the ink ejecting apparatus is changed.

FIG. 5 is a diagram showing a result of an experiment in which the width and application timing of the second pulse signal in the method of the ink ejecting apparatus are changed.

FIG. 6 is a diagram showing a conventional example and an ink ejecting apparatus according to the invention.

FIG. 7 is a diagram illustrating an operation of a conventional example and an ink ejecting apparatus according to the present invention.

FIG. 8 is a diagram showing a driving method of a conventional example.

FIG. 9 is a diagram showing a conventional drive circuit.

FIG. 10 is a diagram showing another example of the driving method of the conventional example.

[Explanation of symbols]

 10 First Drive Waveform 20 Second Drive Waveform 187 Positive Power Supply 600 Ink Ejection Device 603 Actuator Wall 613 Ink Flow Path 619 Electrode 621 Electrode

Claims (5)

[Claims] 1. An ink chamber filled with ink, an actuator for changing the volume of the ink chamber, a single driving power source for applying an electric signal to the actuator, and the single actuator for the actuator. And a control unit configured to change the volume of the ink chamber to eject an ink droplet by applying a pulse signal from the driving power source, the control unit comprising: A first drive waveform signal having a pulse width that is three times or more the one-way propagation time T of the pressure wave in the ink chamber and is an odd multiple is applied to the actuator from the single drive power source, A volume of ink droplets is ejected, and the pulse width is 0.6 times the one-way propagation time T of the pressure wave in the ink chamber at the second resolution which is higher than the first resolution.
A second drive signal having a peak value equal to that of the first drive waveform signal is applied to the actuator from the single drive power source. ,
A method for driving an ink ejecting apparatus, comprising ejecting a second volume of ink droplets smaller than the first volume. 2. The first drive waveform signal has a pulse signal A having a pulse width of 3T or more and an odd multiple, and the same crest value as the pulse signal A, and a pulse width of 0.3.
A pulse signal of T to 1.7T and a delay time Td from the falling timing Tp of the pulse signal A to the central timing Tm of the rising timing Ts and the falling timing Te is 2.25T to 2.75T. The method for driving an ink ejecting apparatus according to claim 1, wherein the method comprises: 3. A pulse signal B of the first drive waveform signal.
Is a pulse width of 0.5T or 1.3T to 1.7T, and a delay time Td is 2.5. 4. The second drive waveform signal has a pulse signal C having a pulse width of 0.6T to 0.9T or 1.1T to 1.4T, and the same crest value as the pulse signal C. , The pulse width is 0.3T to 1.7T, and the delay time Td from the falling timing Tp of the pulse signal C to the central timing Tm between the rising timing Ts and the falling timing Te is 2.25T to.
The method for driving an ink ejecting apparatus according to claim 1, wherein the pulse signal D is 2.75T. 5. A pulse signal D of the second drive waveform signal.
5. The method according to claim 4, wherein the pulse width is 0.5T or 1.5T, and the delay time Td is 2.5.