JP2003145750A - Inkjet device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve quality of a printed image by a method wherein three or more ink drops are stably ejected with respect to one printing command and the ink drops are stably ejected without varying the printed density in a wide temperature range. SOLUTION: Diagram (A) shows a driving signal in the case where three drops of ink are ejected with respect to one print command and the driving signal satisfies expressions of 0.8T <= T1 <= 1.2T, 0.4T <= T2 <= 0.8T, 0.4T <=T3 <= 0.8T, 1.8T <= W2 <= 2.2T, W1 > W2, W1 >2T. T represents a propagating time period in one way that a pressure wave of ink in an ink chamber propagates in one way. When the expressions of T1 = T2 = T3 = T and W1 = W2 = 2T are satisfied as in diagram (C), the ink drops tend to be united during the flying. By setting T1, T2, T3, W1 and W2 in the above ranges, it is possible to stably eject a plurality of the ink drops and to prevent the ink drops from being united.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink ejecting apparatus for ejecting ink from a nozzle by driving an actuator to generate pressure wave vibration in an ink chamber, and more specifically, three ink droplets for one print command. The present invention relates to an ink ejecting device capable of ejecting ink.

[0002]

2. Description of the Related Art Conventionally, a nozzle that ejects ink, an ink chamber that is provided behind the nozzle and that is filled with ink, an actuator that changes the volume of the ink chamber, and an actuator that drives the actuator. An ink ejecting apparatus has been conceived, which includes: a driving unit that generates a pressure wave vibration in the ink chamber and ejects ink from the nozzle. In this type of ink ejecting apparatus, ink can be ejected from the nozzle by driving the actuator by the driving unit to generate pressure wave vibration in the ink chamber.

Here, as the actuator, for example, a piezoelectric element which is deformed by application of a drive voltage can be considered. In this case, a pulsed voltage (hereinafter referred to as a drive pulse) is applied to the piezoelectric element from a drive circuit as a drive means. As a result, ink is ejected. In addition, in this type of ink ejecting apparatus, a plurality of drops of ink are ejected by repeatedly applying drive pulses to one print command.
It is also conceivable to form dots. In this case, one dot can be composed of a large amount of ink, and a dark color image can be formed.

[0004]

However, in the prior art, as shown in FIG.
When three or more drops of ink are ejected for one print command as in the drive waveform shown in (C), T1 = T2 = T3 = TW1 = W2 = 2T. However, T is a one-way propagation time in which the pressure wave of the ink propagates one way in the ink chamber. Further, T1 is the pulse width of the driving pulse P1 for ejecting the first ink, T2 is the pulse width of the driving pulse P2 for ejecting the second ink, and T3 is the third ink. The pulse width of the drive pulse P3 for jetting is set to W1
Represents the interval between the drive pulse P1 and the drive pulse P2, and W2 represents the interval between the drive pulse P2 and the drive pulse P3.

In this case, the timing of application and removal of pressure to the ink chamber coincides with the cycle in which the pressure wave of ink propagates in the ink chamber in one way, that is, coincides with the rising point of the ink pressure wave. , The pressure wave is gradually amplified because the pressure is removed in accordance with the descent point of the pressure wave, so that injection with high pressure efficiency can be performed, but the second and second drops are more effective than the first drop. As compared with the third drop, the pressure applied to the ink at the time of ejection becomes larger, and the flight speed becomes faster for the later ejected ink drops. Therefore, due to the influence of the pressure wave, when ink is ejected from the adjacent nozzles, the ejection becomes unstable when the print commands for the same nozzle continue, or the front and rear ink droplet ejection intervals become smaller. In addition, FIG.
As shown in (B), the ink drops 99 may coalesce during flight. When the ink droplets 99 coalesce during flight in this manner, the print quality deteriorates due to bending in the flight direction. Further, when the temperature of the ink changes, the time T during which the pressure wave of the ink propagates in the ink chamber one way
May change with respect to the timing of application and removal of pressure to the ink chamber, the size of ink droplets may fluctuate, the print density may change, and ejection may become unstable.

The applicant of the present application has previously proposed a method for stably ejecting three or more drops of ink for one print command and preventing coalescence during flight (Japanese Patent Application No. 11- 1
No. 94518), but in this case, after ejecting two drops, a non-ejection pulse with a short pulse width is inserted to suppress pressure fluctuations, and two drops are ejected, resulting in a longer ejection cycle and high-speed printing. Will be difficult. Therefore, the present invention, in an ink ejecting apparatus capable of ejecting three or more drops of ink for one print command, ejects ink drops stably without variation in print density in a wide temperature range, and The purpose is to easily and stably prevent the ink droplets from coalescing during flight, and to improve the print image quality.

[0007]

In order to achieve the above object, the invention according to claim 1 is provided with a nozzle for ejecting ink and a nozzle provided behind the nozzle and filled with ink. An ink chamber, an actuator that changes the volume of the ink chamber, and a drive unit that drives the actuator to generate pressure wave vibration in the ink chamber and perform an ejection operation of ejecting ink from the nozzle. When the driving means ejects three or more drops of ink in response to one print command,
The pulse width of the drive pulse P1 for ejecting the drop ink is T1, the pulse width of the drive pulse P2 for ejecting the ink of the second drop is T2, and the drive pulse P3 for ejecting the ink of the third drop. Is T3, the drive pulse P1 and the drive pulse P2 have an interval W1, and the drive pulse P2 and the drive pulse P3 have an interval W2, T1, T2, T
3, W1 and W2 satisfy the following equation with respect to one-way propagation time T in which the pressure wave of the ink propagates one way in the ink chamber.

0.8T ≤ T1 ≤ 1.2T 0.4T ≤ T2 ≤ 1.2T 0.4T ≤ T3 ≤ 0.8T W1> W2 W1> 2T
When three or more drops of ink were ejected for each print command, the change in image quality was measured by variously changing the pulse widths T1, T2, T3 and the intervals W1, W2.
As a result, by setting 0.8T ≦ T1 ≦ 1.2T 0.4T ≦ T2 ≦ 1.2T 0.4T ≦ T3 ≦ 0.8T W1> W2 W1> 2T, non-injection between pulses as in the conventional case It has been discovered that, without inserting a pulse, a plurality of ink droplets can be stably ejected and their coalescence can be easily and stably prevented in a wide temperature range without variations in print density. There are various possible causes for this, and there are some points that have not yet been elucidated.
First, because T3 is set shorter than the one-way propagation time T and W1 is set longer than 2T, it is difficult for the second and third drops to be affected by the first drop. The reason is that it is possible to suppress the pressure applied to the ink at the time of jetting. Thus, in the present invention, T1, T2, T3
, W1 and W2 are set as described above,
It is possible to easily and stably prevent a plurality of ink droplets from being stably ejected and coalescing during flight. Therefore, the influence of the front and rear ink ejection and the ink ejection from the adjacent nozzles can be eliminated, and the print image quality can be improved satisfactorily and stably. In addition, since it is not necessary to insert a non-ejection pulse between pulses as in the conventional case, high-speed printing can be favorably supported. Furthermore, it is possible to stably eject a plurality of ink droplets in a wide temperature range and to obtain a predetermined print density in a stable manner.

The invention according to claim 2 is characterized in that, in addition to the structure according to claim 1, T2, T3, W1 and W2 further satisfy the following equation. 0.4T ≤ T2 = T3 ≤ 0.8T 1.8T ≤ W2 ≤ 2.2T 2.2T ≤ W1 ≤ 2.8T The inventor has conducted various experiments and found that the above-mentioned T2, T3, W1,
It has been discovered that when W2 satisfies the above equation, the print image quality can be improved more favorably and stably. In the present invention, since T2, T3, W1 and W2 satisfy the above formula, in addition to the effect of the invention according to claim 1, there is an effect that the print image quality can be improved more satisfactorily and stably. Occurs.

The invention according to claim 3 is characterized in that, in addition to the structure according to claim 1, T1, T2 and T3 further satisfy the following equation. T1 ≧ T2> T3 The inventor conducted various experiments to more stably eject a plurality of ink droplets in a wide temperature range when T1, T2 and T3 described above satisfy the above formula, and perform predetermined printing. It was discovered that the concentration can be stably obtained. In the present invention, T1, T2, and T3 satisfy the above formula, and in addition to the effect of the invention of claim 1, a predetermined print density can be stably obtained in a wide temperature range, The image quality can be improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view showing the configuration of an inkjet printer head as an example of the ink ejecting apparatus of the invention. As shown in FIG. 1, the ink jet printer head includes a cavity plate 10 made of a metal plate, a plate type piezoelectric actuator 20,
Also, the flexible flat cable 30 for connecting the external device is sequentially laminated and fixed.

As shown in the exploded perspective view of FIG. 2, the cavity plate 10 is made up of five substantially rectangular thin metal plates consisting of a nozzle plate 11, a manifold plate 12, a spacer plate 13, and a base plate 14. It is constructed by stacking. The nozzle plate 11 is provided with a large number of minute-diameter ink jet nozzles 15 along the longitudinal centerline 11a of the nozzle plate 11 at a minute pitch P. Ink passages 12a are formed in the two manifold plates 12 so as to extend along both sides of the row of the nozzles 15, and the ink passages 12a are formed in both the manifold plates 12.
The nozzle plate 11 and the spacer plate 13 described above.
It has a structure in which it is sealed by stacking.

The base plate 14 is provided with a large number of narrow ink chambers 16 extending in a direction orthogonal to the longitudinal centerline 14a. This ink chamber 16 is shown in an enlarged perspective view of FIG. 3 and a sectional view of FIG.
As shown in the BCD staircase sectional view), the tip ends 16a are located on the center line 14a and are alternately provided so as to extend in opposite directions from the tip end 16a at every other position. The tip 16a of the ink chamber 16 communicates with the nozzle 15 of the nozzle plate 11 described above through a minute through hole 17 formed in the spacer plate 13 and each manifold plate 12. On the other hand, the other end 16b of the ink chamber 16
Are communicated with the above-described ink passage 12a through a through hole 18 formed in the spacer plate 13.

With this structure, the spacer plate 13,
A supply hole 19a formed at one end of the base plate 14,
The ink flowing from 19b into the ink passage 12a is distributed from the ink passage 12a into the ink chambers 16 through the through holes 18, and then from the ink chambers 16 through the through holes 17. To the nozzle 15 corresponding to. It should be noted that each ink chamber 16 is provided with a throttle portion 16c for restricting the flow rate, the plate thickness of which is partially thinned, in a portion adjacent to the other end 16b, and the plate thickness for reinforcement is provided in a substantially central portion for reinforcement. A connecting piece 16d, which is partially thinned, is integrally provided.

On the other hand, the piezoelectric actuator 20, as shown in FIG. 5, has a structure in which three piezoelectric sheets 21, 22 and 23 are laminated, and the piezoelectric sheet 21 in the lowermost stage (closest to the cavity plate 10) among them. On the upper surface, a narrow drive electrode 24 is formed at each location of each ink chamber 16 of the cavity plate 10. Further, the drive electrode 24 is
The one end 24a is formed so as to be exposed on both left and right side surfaces 20c (see FIG. 3) along the longitudinal direction of the piezoelectric actuator 20.

A common electrode 25 common to the ink chambers 16 is formed on the upper surface of the next-stage piezoelectric sheet 22 so that a part 25a of the common electrode 25 is exposed on the left and right side surfaces 20c. ing. Further, on the upper surface of the uppermost piezoelectric sheet 23, the surface electrodes 26 individually facing the drive electrodes 24 and the surface electrodes 27 facing the part 25a of the common electrode 25 are provided on the left and right side surfaces described above. It is provided so as to line up along 20c. Incidentally, reference numerals 24 ', 2
Reference numeral 5'denotes an electrode having a discard pattern.

Referring back to FIGS. 3 and 4, the left and right side surfaces 2 described above
0c includes the drive electrodes 24 and the surface electrodes 2 facing the drive electrodes 24.
A side surface electrode 28 for electrically connecting 6 and 6 and a side surface electrode 29 for electrically connecting a part 25a of the common electrode 25 and the surface electrode 27 are respectively formed. In the above description, the case where only one set of the piezoelectric sheet 21 having the drive electrode 24 and the piezoelectric sheet 22 having the common electrode 25 is laminated has been described.
A plurality of sets of 1 and 22 may be laminated.

The piezoelectric actuator 20 having the above-described structure is laminated and fixed to the cavity plate 10 described above. In addition, this lamination is such that the ink chambers 16 are formed on the lower surface of the portion of the piezoelectric sheet 21 where the driving electrodes 24 are provided on the upper surface.
It is designed to close each of them individually. Further, a flexible flat cable 30 is provided on the upper surface of the piezoelectric actuator 20, and a wiring pattern (not shown) exposed on the lower surface thereof.
Are laminated and fixed so as to be electrically connected to the surface electrodes 26 and 27.

In the ink jet printer head having such a structure, before the ejection command is input, the driving voltage is applied to all the driving electrodes 24 in advance, and the driving electrodes 24 and the common electrode 25 are supplied to all the ink chambers 16. Distortion in the stacking direction is generated by the piezoelectric force at the portion of the piezoelectric sheet 22 that is sandwiched between and, and the inner volume of the ink chamber 16 is reduced. The inner volume of the ink chamber 16 is expanded by releasing the application of the voltage to the drive electrode corresponding to the ink chamber 16 in which the ink is ejected in each drive electrode 24 to eliminate the distortion, and then the drive electrode 24 By applying a voltage to the piezoelectric sheet 22, the piezoelectric sheet 22 is returned to the distorted state, and the ink chamber 1
It is possible to apply pressure to the ink in 6 and eject the ink in the form of droplets from the nozzle 15. Note that the ink chamber 16 is always expanded and the voltage is applied to the drive electrode 24 to reduce the ink chamber 16 to reduce the ink chamber 1.
It is also possible to apply a pressure for ejecting to the ink inside 6.

In the ink jet printer head of this embodiment, the side surface electrodes 28 of the base plate 14,
Punching holes 41 and 42 are formed in a portion facing 29. Therefore, as shown in FIG. 6, when the piezoelectric actuator 20 is laminated on the cavity plate 10, it is possible to favorably prevent the side electrode 28 or 29 from coming into contact with the base plate 14 and short-circuiting.

Next, in the present embodiment, since the drive voltage is applied to the drive electrode 24, the piezoelectric actuator 20
A drive circuit 100 described below is connected to the surface electrodes 26 and 27 of the above through a flexible flat cable 30. FIG. 7 is a circuit diagram showing the configuration of a drive circuit 100 as a drive unit used in the inkjet printer head of this embodiment.

As shown in FIG. 7, the drive circuit 100 comprises a charging circuit 182, a discharging circuit 184, and a pulse control circuit 186. Further, in FIG. 7, the piezoelectric sheet 22, the driving electrode 24, and the common electrode 25 are represented by a capacitor 191, and the terminals 191A and 191B of the capacitor 191 correspond to the driving electrode 24 and the common electrode 25, respectively. As shown in FIG.
A is the drive circuit 100, and the terminal 191B is the ground 623.
, Respectively.

Input terminal 18 provided in charging circuit 182
7 and the input terminal 188 provided in the discharge circuit 184,
The drive electrode 24 (terminal 191) of each ink chamber 16
A) E (V) drive voltage (eg 20V) or 0
This is a terminal for inputting a signal for applying a voltage of (V) from a pulse control circuit 186 described later.

The charging circuit 182 includes resistors R101 and R10.
2, R103, R104, R105, and transistors TR101, TR102. The base of the transistor TR101 is connected to the input terminal 187 via the resistor R101 and grounded via the resistor R102. The emitter of the transistor TR101 is directly grounded, and the collector is a positive power source 18 of E (V).
9 through a resistor R103. The base of the transistor TR102 is connected to the positive power source 189 via the resistor R104, and is connected to the collector of the transistor TR101 via the resistor R105. The emitter of the transistor TR102 is the positive power source 18
9 and the collector is connected to the terminal 191A via the resistor R120.

Therefore, the ON signal (+
5 V) is input, the transistor TR101 becomes conductive, and the current from the positive power source 189 is applied to the transistor TR10.
1 flows from the collector to the emitter. Therefore, the resistors R104 and R105 connected to the positive power source 189
Voltage of the transistor TR102 increases,
The current flowing to the base of the transistor TR10 increases,
There is conduction between the emitter and collector of No.2. The voltage of E (V) from the positive power source 189 is applied to the transistor TR10.
Terminal 191A of the capacitor 191 (that is, the drive electrode 24) via the collector and emitter of R2, and the resistor R120.
Applied to.

Next, the discharge circuit 184 will be described.
The discharge circuit 184 is composed of resistors R106 and R107 and a transistor TR103. Transistor TR1
The base of 03 is connected to the input terminal 188 via the resistor R106.
And is grounded via a resistor R107. The emitter of the transistor TR103 is directly grounded, and the collector is connected to the terminal 19 via the resistor R120.
It is connected to 1A. Therefore, when an ON signal (+ 5V) is input to the input terminal 188, the transistor TR10
3 becomes conductive, and the terminal 191A (that is, the drive electrode 24) of the capacitor 191 is grounded via the resistor R120.

Therefore, the pulse control circuit 186
When an ON signal is input from the input terminal 187 to the input terminal 187 and an OFF signal is input to the input terminal 188, E
If the drive electrode of (V) can be applied and the OFF signal is input from the pulse control circuit 186 to the input terminal 187 and the ON signal is input to the input terminal 188, the drive electrode 24 is 0 (like the common electrode 25). V).

The charging circuit 182 and the discharging circuit 18
Although the change of the voltage applied to the drive electrode 24 via 4 has a delay according to the electrostatic capacity of the piezoelectric sheet 22 in reality, in the following description, it is input to the input terminals 187 and 188. It is assumed that the change in the signal applied to the drive electrode 24 and the change in the voltage applied to the drive electrode 24 coincide in timing.

Next, the pulse control circuit 186 is provided with a CPU 210 for performing various arithmetic processes. The CPU 210 has a RAM 212 for storing print data and various data, a control program for the pulse control circuit 186, and a later-described program. ROM 214 for storing sequence data for generating ON / OFF signals of the waveform of FIG.
And are connected.

Further, the CPU 210 is connected to an I / O bus 216 for exchanging various data, and a print data receiving circuit 218 and pulse generators 220 and 222 are connected to the I / O bus 216. The output of the pulse generator 220 is the input terminal 1 of the charging circuit 182.
87, and the output of the pulse generator 222 is input to the input terminal 188 of the discharge circuit 184.

In the pulse control circuit 186 thus configured, the CPU 210 controls the pulse generators 220 and 222 according to the sequence data stored in the ROM 214, and supplies the drive voltage to the drive electrode 24 at the timing corresponding to the sequence data. Apply. The pulse generators 220 and 222, the charging circuit 182, and the discharging circuit 184 are provided in the same number as the nozzles 15 of the inkjet printer head.
The CPU 210 outputs a drive signal to the drive electrode 24 according to the print data, and ejects ink from the corresponding nozzle 15.

Next, FIG. 8A shows an example of the waveform of the drive signal (hereinafter referred to as the drive waveform) in the drive circuit 100 of the present embodiment. The drive circuit 100 outputs these drive signals while being moved by the carriage. Fig. 8 (A) shows that 3 prints for one print command.
The drive waveforms for ejecting a drop of ink are shown as T
1 is the pulse width of the drive pulse P1 for ejecting the first drop of ink, T2 is the pulse width of the drive pulse P2 for ejecting the second drop of ink, and T3 is the ejection of the third drop of ink. Is the pulse width of the drive pulse P3, W1 is the interval between the drive pulse P1 and the drive pulse P2, and W2 is the interval between the drive pulse P2 and the drive pulse P3. Further, the peak value (voltage value) of each of the drive pulses P1, P2, P3 is E (V).

Here, the applicant of the present application has found that 0.8T≤T1≤1.2T 0.4T≤T2≤1.2T 0.4T≤T3≤0.8T W1> W2 W1> 2T (where T is an ink). By setting the pressure wave of the ink to propagate one way in the chamber 16), the ink droplet 99 (FIG. 9) can be obtained without inserting a non-ejection pulse between the pulses as in the conventional case.
It has been discovered that coalescence of can be easily and stably prevented. There are various possible causes for this, and there are unclear points.
For example, the following causes are possible. First, because T3 is set shorter than the one-way propagation time T and W1 is set longer than 2T, it is difficult for the second and third drops to be affected by the first drop. The reason is that it is possible to suppress the pressure applied to the ink at the time of jetting.

Therefore, in the present embodiment, T1, T2, T3, W1, W2 are set by setting the sequence data.
Is set within the above range. Therefore, the ink droplets 99 ejected from the nozzles 15 do not coalesce during flight as shown in FIG. 9A, and the print image quality can be improved satisfactorily. Moreover, since the above-mentioned coalescence can be stably prevented, the influence of the previous ink ejection in the nozzle 15 or the ink ejection from the adjacent nozzle 15 is also eliminated, and the print image quality is improved satisfactorily and stably. be able to.
In addition, since it is not necessary to insert a non-ejection pulse between pulses as in the conventional case, high-speed printing can be favorably supported.

Further, T1 = T, W2 = 2.0T, T2
= T3 is fixed, various values of W1, T2 and T3 are changed, various test patterns are printed, and the print quality is compared. Table 1 shows the results. In Table 1, ◯ indicates that printing could be performed satisfactorily, and x indicates that ink was bent in the ejection direction and dots could not be formed at the target position, or satellite (following the main ink droplet 99). It shows that the dots could not be formed neatly due to the generation of extra ink droplets that jumped out.

[0036]

[Table 1]

T1 is 0.8T≤T1≤1.2T
Further, it has been confirmed by experiments that substantially the same results as above can be obtained even when W2 is 1.8T≤W2≤2.2T. Therefore, as shown in Table 1, 0.8T≤T1≤1.2T 0.4T≤T2 = T3≤0.8T 1.2T≤W1≤2.8T 1.8T≤W2≤2.2T W1> W2 Good print image quality was obtained in the range of W1> 2T, but good print image quality was not obtained in the region outside this range.
In this case, T2 and T3 are shorter than the one-way propagation time T, and W
Since 1 is set to be longer than 2T, it is difficult for the second and third drops behind to be affected by the first drop, and it is possible to suppress the pressure applied to the ink when ejecting the second and third drops. it can,
it is conceivable that.

Further, by changing the ambient temperature stepwise, T1,
An experiment was conducted to find the optimum range of T2 and T3. here,
W1 and W2 were the same as in the above experiment. Table 2 shows the results. ○ indicates that the jetting was stable and high-density printing image quality was obtained, △ indicates that the jetting was stable, but the density was slightly inferior, and × indicates that the jetting was unstable (curving or satellite formation occurred. ).

[0039]

[Table 2]

Therefore, as shown in Table 2, 0.8T≤T1≤1.2T 0.4T≤T2≤1.2T 0.4T≤T3≤0.8T T1≥T2> T3 1.2T≤W1≤ 2.8T 1.8T ≦ W2 ≦ 2.2T In the range of W1> W2 W1> 2T, good print image quality was obtained in a wide temperature range.

The present invention is not limited to the above-described embodiments, and can be implemented in various forms without departing from the scope of the present invention. For example, in the above embodiment, the ink jet printer head is provided with the cavity plate 10 and the plate type piezoelectric actuator 2.
However, the present invention can also be applied to an ink ejecting apparatus of the type in which the side wall of the ink chamber is formed of a piezoelectric element (for example, see Japanese Patent Laid-Open No. 10-296975). Further, although a rectangular drive waveform is used in the above embodiment, a trapezoidal drive waveform may be used. In this case, T1, T2, T3, W1, and W2 may be calculated with reference to the center of the hypotenuse, as shown in FIG. Furthermore, the present invention can be similarly applied to the case of ejecting four or more drops of ink. Furthermore, after ejecting the above-mentioned three drops of ink, a non-ejection pulse for suppressing pressure fluctuation is added, whereby the cycle of the print command can be shortened and high-speed printing can be performed.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a configuration of an inkjet printer head as an example of an ink ejecting apparatus of the invention.

FIG. 2 is an exploded perspective view showing a configuration of a cavity plate of the head.

FIG. 3 is an enlarged perspective view showing a configuration of a main part of the cavity plate.

FIG. 4 is an ABC showing the structure of the cavity plate.
It is a D stairway sectional view.

FIG. 5 is an exploded perspective view showing a configuration of a piezoelectric actuator of the head.

FIG. 6 is the above ABC when a piezoelectric actuator is laminated.
It is a D stairway sectional view.

FIG. 7 is a circuit diagram showing a configuration of a drive circuit used in the head.

FIG. 8 is an explanatory diagram showing drive waveforms in the head and a conventional device.

FIG. 9 is an explanatory diagram showing a difference in effects based on the difference in the drive waveform.

[Explanation of symbols]

10 cavity plate 11 nozzle plate 12 Manifold plate 13 Spacer plate 14 Base plate 15 nozzles 16 ink chamber 20 Piezoelectric actuator 21,22,23 Piezoelectric sheet 24 Drive electrode 25 common electrode 26,27 surface electrode 28,29 Side electrode 30 flexible flat cable 99 ink drops 100 drive circuit 182 charging circuit 184 discharge circuit 186 pulse control circuit

Claims (3)

[Claims] 1. A nozzle that ejects ink, an ink chamber that is provided behind the nozzle and that is filled with ink, an actuator that changes the volume of the ink chamber, and the actuator that is driven to drive the ink. An ink ejecting apparatus comprising: a driving unit configured to generate a pressure wave vibration in a chamber to eject ink from the nozzle, wherein the driving unit has three or more drops for one print command. When ejecting the first ink, the pulse width of the drive pulse P1 for ejecting the first ink is T1, the pulse width of the drive pulse P2 for ejecting the second ink is T2, and the third ink The pulse width of the drive pulse P3 for injecting the liquid is T3, and the interval between the drive pulse P1 and the drive pulse P2 is W1.
, And when the interval between the drive pulse P2 and the drive pulse P3 is W2, T1, T2, T3, W1, and W2 are one-way propagation time T in which the pressure wave of the ink propagates one way in the ink chamber.
An ink jet device characterized by satisfying the following equation. 0.8T≤T1≤1.2T 0.4T≤T2≤1.2T 0.4T≤T3≤0.8T W1> W2 W1> 2T 2. The ink ejecting apparatus according to claim 1, wherein T2, T3, W1 and W2 further satisfy the following equation. 0.4T ≤ T2 = T3 ≤ 0.8T 1.8T ≤ W2 ≤ 2.2T 2.2T ≤ W1 ≤ 2.8T 3. The ink ejecting apparatus according to claim 1, wherein T1, T2, and T3 further satisfy the following equation. T1 ≧ T2> T3