JP2001315330A - Ink drop projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of conventional driving method for an ink drop ejector where the pulse width and application period of a pulse for driving an electromechanical conversion means are set equal to an integer times of AL, which is equal to one half of the acoustic resonance period of a pressure generating chamber, that the operation is unstable when the ejector is driven with a high frequency. SOLUTION: The driving pulse is set such that at least one of the pulse width and application period thereof is substantially not equal to an integer times of AL.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink droplet ejecting apparatus for ejecting ink droplets and attaching them to a recording material to form an image, and more particularly to an ink droplet ejecting apparatus for ejecting ink droplets on a drop-on-demand basis. .

[0002]

2. Description of the Related Art Ink droplet ejecting apparatuses for ejecting ink droplets on a drop-on-demand basis are widely used at present. However, high-speed operation and improvement of image quality are desired, and research and development are being carried out therefor. .

[0003] The ink droplet ejecting apparatus includes an electromechanical conversion means, a pressure generating chamber for generating pressure by the operation of the electromechanical conversion means, and a droplet formed at one end of the pressure generating chamber. A nozzle for emitting ink to the pressure generating chamber, and an ink supply unit for supplying ink to the pressure generating chamber. By applying a driving pulse to the electromechanical conversion means, the ink droplet is ejected from the nozzle by the pressure generated in the pressure generating chamber. It is a device which injects.

Various types of ink droplet ejecting devices have been proposed. One of them is a shear mode ink droplet ejecting device, which is described in Japanese Patent No. 2969570 and the like. In these ink droplet ejecting apparatuses, a drive pulse composed of two consecutive pulses for first increasing the volume of the pressure generation chamber and then reducing the volume is utilized by utilizing the acoustic resonance of the pressure generation chamber. A method has been used in which the first pulse and the second pulse of the drive pulse are used together for ejecting ink droplets by applying the first pulse and the second pulse in conformity with the physical resonance period. That is, the pulse width of the first pulse is set to AL which is １ ／ of the acoustic resonance period described later, and the pulse width of the second pulse is set to 2
As the AL, when a piezoelectric element, which is an electromechanical conversion unit, is driven using such a driving pulse, it is used as an ink that can efficiently eject ink droplets.

[0005]

SUMMARY OF THE INVENTION One of a plurality of pulses
If the pulse width of the first drive pulse applied is set to AL, the emission speed for a constant drive voltage becomes maximum, and the droplet can be emitted with high energy efficiency. However, when the viscosity of the ink to be used is low, when a droplet is ejected at a high frequency, or when a large amount of a droplet is ejected, there is a problem that the droplet speed limit at which the ink can be ejected stably becomes low, and the problem is further increased. There has been a demand for a driving method capable of stably ejecting ink droplets up to the ink droplet speed.

When the ejection period of the ink droplet is also set to an integral multiple of AL, the phase of acoustic vibration in the pressure generating chamber due to continuous ejection is matched, and stable and efficient driving can be performed. However, usually, in an ink jet recording apparatus, the ejection cycle of ink droplets is determined by an encoder signal when a carriage on which an ink droplet ejecting apparatus is mounted is scanned. However, there is a problem that the ejection cycle of the ink droplet fluctuates, which causes the ink droplet speed, the droplet amount, and the ejection state to be unstable. Therefore, more stable driving conditions have been desired.

An object of the present invention is to provide an ink droplet ejecting apparatus which solves the above-mentioned problems in the conventional ink droplet ejecting apparatus and which can be driven at a high speed and can form a high quality image. Aim.

[0008]

The above-mentioned object of the present invention is achieved by any of the following inventions.

1. Electro-mechanical conversion means, a pressure generation chamber for generating pressure by operation of the electro-mechanical conversion means, a nozzle formed at one end of the pressure generation chamber, for emitting ink droplets by the action of pressure, An ink supply unit for supplying the ink, and an ink droplet ejecting apparatus having a drive pulse generation unit for driving the electro-mechanical conversion unit,
A drive pulse including a first drive pulse for generating a negative pressure in the pressure generation chamber, and a second drive pulse for subsequently generating a positive pressure in the pressure generation chamber,
At least one of the pulse width of the first drive pulse and the application cycle of the drive pulse is equal to the AL of the pressure generation chamber.
The drive pulse generation unit outputs the drive pulse set to be substantially deviated from an integral multiple of (a half of the resonance cycle of the pressure wave generated in the pressure generation chamber) by the electric pulse.
An ink droplet ejecting apparatus, wherein the ink droplet is ejected from the nozzle by applying to a mechanical conversion unit.

[0010] 2. The drive pulse generating means includes:
2. The ink droplet ejecting apparatus according to claim 1, wherein the driving pulse has a pulse width longer than the AL of the pressure generating chamber.

3. The driving pulse generating means may be arranged such that AL <W
Pulse width W1 of the first drive pulse of 1 <1.3AL
3. The ink droplet ejecting apparatus according to claim 2, wherein the first driving pulse having the following is generated.

4. The drive pulse generating means may generate the first drive pulse having a pulse width that maximizes a critical flight speed at which a stable flight without emitting bubbles from the nozzle can be stably emitted. 3. The ink droplet ejection device according to the item 2, wherein

5. The drive pulse generating means includes:
Generating the second drive pulse having a pulse width substantially twice as large as that of the first to fourth drive pulses.
The ink droplet ejecting apparatus according to any one of claims 1 to 7.

6. The ink droplet ejecting apparatus according to any one of claims 1 to 4, wherein the driving pulse generating unit generates the second driving pulse having a pulse width of substantially 2AL.

[0015] 7. 2. The ink droplet ejecting apparatus according to claim 1, wherein the driving pulse generating unit generates the driving pulse whose application cycle is set to be substantially deviated from an integral multiple of the AL.

8. The driving pulse generating means generates the driving pulse having the application period T substantially set in a range of nAL <T <(n + 2/3) AL (where n is an integer of 3 or more). 8. The ink droplet ejecting apparatus according to the item 7, wherein

9. The drive pulse generating means includes:
9. The ink droplet ejecting apparatus according to the item 7 or 8, wherein the second driving pulse having a pulse width substantially twice as large as the driving pulse is generated.

10. 9. The ink droplet ejecting apparatus according to 7 or 8, wherein the driving pulse generating means generates the second driving pulse having a pulse width of substantially 2AL.

11. The electric-mechanical conversion means includes a first
An electrode and a second electrode are provided, and the driving pulse generating means applies the first driving pulse to the first electrode and the second driving pulse having the same polarity as the first driving pulse to the second electrode. 2. The method according to item 1, wherein two drive pulses are applied.
11. The ink droplet ejection device according to any one of items 10 to 10.

[12] The driving pulse generating means is 2 μs
Any one of the above items 1 to 11, wherein the first drive pulse and the second drive pulse each comprising a rectangular wave having the following rise and fall times are applied.
Item 8. An ink droplet ejecting apparatus according to Item 1.

13. The drive pulse generating means applies the first drive pulse and the second drive pulse, each of which is a rectangular wave having a rise and fall time of 1/4 or less of a pulse width. 12. The ink droplet ejection device according to any one of items 11 to 11.

[0022]

1 and 2 show an example of an ink droplet ejecting apparatus according to an embodiment of the present invention.

FIG. 1 is a schematic diagram of an ink droplet ejecting apparatus according to an embodiment of the present invention, and FIG. 2 is a view showing the operation of the ink droplet ejecting apparatus.

In FIG. 1, 1 is an ink tube, 2 is a nozzle forming member, 3 is a nozzle, S is a side wall as electromechanical conversion means, 6 is a cover plate, 7 is an ink supply port, and 8 is a substrate. As shown in FIG. 2, the pressure generating chamber A, which is an ink flow path, is formed by the side wall S, the cover plate 6, and the substrate 8. The nozzle is formed in each pressure generating chamber, but is omitted in a part of FIG.

FIG. 1 is a sectional view of one pressure generating chamber having one nozzle. FIG. 2A shows an ink droplet ejecting apparatus H which operates in an actual shearing mode. Thus, between the cover plate 6 and the substrate 8, a plurality of side walls S as electric-mechanical conversion means, that is, S1, S2,.
+1 pressure generating chambers A, ie, A1, A2,.
-Many An are comprised. Pressure generating chambers A1, A2,
.. An has one end connected to a nozzle 3 formed in the nozzle forming member 2 and the other end connected to an ink tank (not shown) by a supply port 7 and an ink tube 1 constituting an ink supply unit. Reference numeral 3 denotes an ink meniscus formed by ink. For example, electrodes Q1 and Q2 formed in close contact with the side wall S1 and electrodes Q3 and Q4 formed in close contact with the side wall S2 are provided. Similarly, electrodes are formed in close contact with the respective side walls. FIG.
As shown in (b), for example, the electrode Q as the second electrode
1 is connected to the ground, and the electrode Q2 as the first electrode is connected to a drive pulse generation circuit DRC as drive pulse generation means, as shown in FIG. 7, with a peak value V1, a pulse width W1 and a positive voltage. Pulse P which is the first drive pulse
1. A pulse P2, which is a peak value V2, a pulse P2 which is a second driving pulse of a negative voltage with a pulse W2, and a driving pulse P0 including a period E of zero voltage are applied. The drive pulse P0 in FIG.
Although the absolute values of 1 and V2 are equal, it is not a condition that the voltages V1 and V2 are equal. Similarly, the electrode Q4 as the second electrode is connected to the ground, and the electrode Q3 as the first electrode is connected.
When the drive pulse P0 is applied to the nozzle 3, the ink droplet flies from the nozzle 3 by the operation described below. In the prior art, assuming that the half of the acoustic resonance period of the pressure generating chamber A is AL (time), the drive pulse P0 shown in FIG. The pulse width W of the second pulse P2 substantially equal to AL and subsequent
2 is substantially equal to 2AL, and the pulse width during the zero (earth) voltage period E is substantially an integer multiple of AL (eg, 2A).
L). Such a driving pulse P
With the configuration of 0, the pressure generating chamber A operates efficiently and the flying speed of the ink is maximized. AL corresponds to the length of the pressure generating chamber.

The side walls S1, S2,... Are composed of two side walls S1a, S2a,... And S1b, S2b,. Have been. When the driving pulse is not applied to the electrodes Q2 and Q3, the side walls S1 and S2 do not deform as shown in FIG. 2A, but when the first pulse P1 is applied to the electrodes Q2 and Q3, the polarization direction of the piezoelectric material is changed. An electric field is generated in a direction perpendicular to the side walls, so that the side walls S1a and S1b undergo shear deformation in the joint surfaces of the side walls, and the side walls S2a and S2b similarly undergo shear deformation in the opposite direction, as shown in FIG. 2 (b). S1a,
S1b and the side walls S2a, S2b are deformed outwardly from each other, and in this example, the volume of the pressure generating chamber A1 is increased, and a negative pressure is generated in the pressure chamber A1. Next, as shown in FIG. 2C, the side walls S1a and S1b are generated by the subsequent second pulse P2.
S2a and S2b are deformed in opposite directions to each other, the volume of the pressure generating chamber A1 is rapidly reduced, a positive pressure is generated in the pressure generating chamber A1, and one of the inks filling the pressure generating chamber A1 is removed. The ink meniscus in the nozzle 3 is changed by the unit, and an ink droplet is ejected from the nozzle 3. Each of the pressure generating chambers also operates by applying a drive pulse, and ejects ink droplets.

As described above, when the side walls S1 and S2 of the pressure generating chamber A1 are deformed, the adjacent pressure generating chamber A2 is affected, and therefore, usually, for example, A1, A4, A7,.
Are driven by pulses of the same cycle, and A2, A
5, A8... Are driven.

The flying of the ink droplets utilizes the acoustic resonance (hereinafter referred to as resonance) of the pressure generating chamber, and first expands the volume of the pressure generating chamber by a positive voltage pulse P1 as a first drive pulse. A pulse P as a subsequent second drive pulse
2, a method of reducing the volume of the pressure generating chamber to fly ink droplets is used. That is, in the prior art, the pulse width W1 of the pulse P1 is changed to the pressure generation chambers A1, A1.
By setting the pulse width W2 of the pulse P2 to 2AL and the length of the zero-voltage period E to AL, which is substantially equal to AL which is one half of the resonance period of 2,.
It is common practice to increase the flying efficiency of ink.

As described above, in general, when the pressure generating chamber has a simple hollow structure and the pressure generated by driving the electromechanical conversion means repeatedly propagates and reflects in the pressure generating chamber as a pressure wave to cause acoustic resonance. When the driving of the electromechanical conversion means is performed at an interval of の of the acoustic resonance period, that is, at AL, efficient driving utilizing acoustic resonance can be performed. Is often set to be substantially an integral multiple of AL.

In order to perform the drive utilizing such acoustic resonance, the pressure generated by the drive of the electromechanical conversion means must propagate as a pressure wave. As shown in FIG. The drive waveform applied to the means must be constituted by a square wave with a rise time ΔT and a fall time δT sufficiently short compared to the acoustic resonance period. It is preferable that the rise and fall times, ΔT, and δT of the rectangular wave are set to values equal to or less than １ ／ of the pulse width in relation to the pulse width of the rectangular wave.

Further, the amount of ink in the nozzle 3 and the pressure generating chambers A1, A2,... Decreases due to the flying of the ink droplet, but the amount of decrease in the amount of ink is reduced by the nozzle 3 and the ink supply unit due to the capillary force of the ink. Are supplied from the ink tube 1 and the ink inlet 7 to the pressure generating chambers A1, A2,...

FIGS. 1 and 2 show an example of such a mechanical configuration of the embodiment of the present invention. FIGS. 3, 4, 5, and 6 show other examples.

FIG. 3 is a sectional view taken along the ink flow path of the pressure generating chamber of the ink droplet ejecting apparatus. The same components as those shown in FIG. 1 are denoted by the same reference numerals.

L in FIG. 3 is the length of the pressure generating chamber A, and is A which is one half of the acoustic resonance period of the pressure generating chamber A.
L is represented by AL ≒ L / AC. AC is the velocity of the pressure wave in the pressure generating chamber. Note that the length of the pressure generation chamber A does not exactly match the geometric length L of FIG. 3, but is the effective length of the pressure generation chamber A, that is, A1, A2,. . ≒ in the above formula has such a meaning.

The AL of the pressure generating chamber A measures the velocity of an ink droplet emitted by applying a rectangular wave to the side wall S as an electromechanical conversion means of the ink droplet ejecting apparatus, and keeps the voltage value of the rectangular wave constant. When the pulse width of the rectangular wave is changed, the pulse width is determined as the pulse width at which the flying speed of the ink droplet becomes maximum.

FIG. 4 shows the arrangement of the pressure generating chambers of the ink droplet ejecting apparatus shown in FIG. 3 and the operation of each pressure generating chamber when a drive pulse is applied.

The pressure generating chambers, that is, A1, A2,... Are formed with an air channel D formed as an air gap therebetween, and serve as electromechanical conversion means made of a piezoelectric material forming the pressure generating chamber A. An electrode Qa as a first electrode is formed on a side wall S of the substrate, and an electrode Qd as a second electrode is formed on a side wall forming an air channel D.

First, as shown in FIG. 4B, as a first stage, the volume of the pressure generating chamber A is enlarged, and a first driving pulse of a positive voltage + V for generating a negative pressure in the pressure chamber A is performed. Is applied to the electrode Qa. Then, FIG.
As shown in (a), a pulse P2 as a second drive pulse of a negative voltage -V for reducing the volume of the pressure generation chamber A and generating a positive pressure in the pressure chamber A is applied to the electrode Qa. .

As described above, by applying the driving pulse P0 composed of the pulses P1 and P2 to the electrode Qa, the ink droplet is emitted from the nozzle 3.

FIGS. 6A and 6B show the voltages of the electrodes Qa and Qd in driving the pressure generating chamber A described above. FIG. 6 (a)
As apparent from (b), in this driving, a positive pulse P1 and a negative pulse P2 are applied to the electrode Qa.

As a driving method of the ink droplet ejecting apparatus, there is another method described below. FIGS. 6C and 6D show the voltages of the electrodes Qa and Qd in the other method. In this method, as shown in FIGS. 6C and 6D, a positive voltage pulse P1 is applied to the electrode Qa. On the other hand, a positive voltage pulse P2 is applied to the electrode Qd.

The expansion of the volume of the pressure generating chamber A is described in FIG.
In the driving step performed in the same manner as shown in FIG. 5A and reducing the volume of the pressure generating chamber A, as shown in FIG. 5B, a positive + V voltage is applied to the electrode Qd of the air channel. FIG. 5A in which a negative voltage is applied to the electrode Qa
Driving is performed with the same effect as in the case of.

The driving methods shown in FIGS. 5B, 6C and 6D are advantageous in terms of circuit design in that they can be driven by using only positive voltage pulses.

In the embodiment of the present invention, the side wall S is driven by a pulse generating circuit DRC as a driving pulse generating means.
Includes a pulse P1 and a subsequent pulse P2. At least one of the pulse width of the pulse P1 and the application cycle of the drive pulse P0 is set substantially out of an integral multiple of AL which is one half of the resonance cycle of the pressure generating chamber A.

As a result, the droplet speed limit at which stable ejection can be performed is increased, and a more stable ejection state can be realized. Thus, a small number of dots having small size and position fluctuations are formed on the recording material, and a high quality image can be formed.

In particular, it is desirable to set the pulse width W1 of the pulse P1 to be larger than AL.
By setting the pulse width W1 of AL to WAL <W1 <1.3AL, it is possible to increase the limit value of the flying speed of the ink droplet, to further stabilize the flying of the ink droplet, and to form a better image. It becomes possible. When the pulse width W1 of the pulse P1 is out of the range of the above inequality, the limit value of the flying speed decreases.

Another feature of the embodiment of the present invention is that
The purpose of the present invention is to enable high-quality image recording by stabilizing the flight of ink droplets. The pulse width of the pulse P1 is adjusted so that the ink droplets can be ejected from the nozzles 3 without causing air entrainment. This is realized by setting the pulse width at which the speed limit value becomes maximum.

By setting the pulse width of the pulse P2, the pressure wave generated by the pulse P1 can be canceled and calmed down after ejection of the droplet. In the present embodiment, it has been confirmed that by applying the pulse P2 having a pulse width substantially twice as large as the pulse P1, the pressure wave generated by the pulse P1 can be effectively canceled and calmed down after ejection of the droplet. . More preferably, by setting the pulse width of the pulse P2 to be substantially 2AL, more stable droplet ejection becomes possible.

In addition to the means for setting the pulse width of the pulse P1 to be larger than AL, the flying of the ink droplet can also be performed by setting the application cycle of the drive pulse P0 to be substantially shifted from an integral multiple of AL. , And a high-quality image can be formed.

In particular, the application period T of the drive pulse P0 is nA
When L <T <(n + 2/3) AL (where n is an integer of 3 or more), the ink droplets fly stably and high image quality is obtained. When the application cycle of the drive pulse P0 is out of the range of the above inequality, the influence of the variation of the application cycle of the drive pulse due to the variation of the scanning speed of the carriage tends to appear on the flying speed of the ink droplet.

Means for setting the pulse width of the pulse P1 to be larger than AL and the application cycle of the drive pulse P0 to AL
The means for setting the values so as not to be substantially equal to an integral multiple of the above is effective either independently or in combination, and a high-quality image can be formed.

[0052]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS AL which is a characteristic value of a pressure generating chamber, that is, a value of 1/2 of an acoustic resonance period of the pressure generating chamber, is obtained by applying a driving pulse having a repetition period T sufficiently long in the above driving waveform to an ink droplet. By applying the voltage to the piezoelectric element of the ejection device and measuring the velocity of the ink droplet when the pulse width W1 of the rectangular wave is changed while keeping the voltage value V of the rectangular wave constant, the pulse at which the velocity of the ink droplet becomes maximum is measured. Required as width.

Example 1 The characteristic value AL of the ink droplet ejection device of this example was 8.8 μs from the measurement results shown in FIG. That is, by setting the pulse width W1 of the drive waveform to this AL, the droplet speed can be obtained most efficiently with respect to the drive voltage.

In the ink droplet ejecting apparatus H shown in FIG. 3, the repetition period T is set to 5AL in the above driving waveform, the pulse width W1 of the rectangular wave is changed, and the driving voltage value V is increased in the driving waveform of each pulse width. FIG. 9 shows the result of measurement of the critical droplet speed at which ejection is possible immediately before bubbles are entrained from the nozzle. The limit droplet speed is defined by the pulse width W1 as A
It becomes maximum at 9.7 μs (1.1 AL), which is larger than L, and can be stably emitted up to a larger droplet velocity than when W1 is set to AL in the range of AL <W1 <1.3AL. Was.

Embodiment 2 In a droplet ejecting apparatus in which the characteristic value AL of the pressure generating chamber is 4.8 μs, the pulse width W1 of the driving waveform is set to 5.2 μs.
s, the drive voltage value V is fixed at 15 V, and the speed and volume of the ejected droplets are measured by repeatedly changing the ejection period T. FIG. 10 shows the results. from this result,
In the case where the emission cycle (equal to the application cycle of the drive pulse P0) fluctuates, the fluctuations in the flying speed of the ink droplet and the volume of the ink droplet can be reduced to maintain a stable emission state. It can be seen that it is preferable to set (n + ／) AL which is the maximum point or the minimum point of the inflection curve.

In the above embodiment, the rise time ΔT and the fall time δT of the pulse P1 and the pulse P2 are set.
Is constituted by a 0.5 μs rectangular wave, the above condition can be satisfied.

[0057]

According to the first aspect of the present invention, a high and stable flying speed of ink droplets is realized, and a high quality image can be formed at high speed.

According to the second, third or fourth aspect of the present invention,
Ink droplets can be made to fly at high speed, and high-quality images can be stably formed.

According to the fifth or sixth aspect of the present invention, in particular, when the ink droplets are continuously and rapidly flown at a high speed, the emission state can be kept stable and a high quality image can be stably formed.

According to the seventh aspect of the present invention, it is possible to suppress the fluctuation of the ink droplet interval due to the fluctuation of the scanning speed of the carriage, and to form a high quality image.

According to the eighth aspect of the invention, it is possible to form a high-quality image by suppressing the fluctuation of the ink droplet interval particularly well.

According to the ninth and tenth aspects of the present invention, especially when the ink droplets are continuously and rapidly flown, the emission state can be kept stable and a high-quality image can be stably formed.

According to the eleventh aspect of the present invention, a high-speed and high-quality shear mode ink droplet ejecting apparatus is realized.
Since the drive pulse generating means can be constituted by a drive circuit having only a single-polarity power supply, circuit design and manufacture are easy.

According to the twelfth or thirteenth aspect of the present invention, efficient driving utilizing acoustic resonance can be performed, and power consumption for driving can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an ink droplet ejecting apparatus.

FIG. 2 is a diagram illustrating the operation of the ink droplet ejection device.

FIG. 3 is a cross-sectional view along an ink flow path of a pressure generating chamber of the ink droplet ejecting apparatus.

FIG. 4 is a diagram showing the operation of a pressure generating chamber.

FIG. 5 is a diagram showing the operation of a pressure generating chamber.

FIG. 6 is a diagram showing a driving pulse.

FIG. 7 is a diagram showing a waveform of a driving pulse.

FIG. 8 is a graph showing a relationship between a pulse width of a first drive pulse and a flying speed of an ink droplet.

FIG. 9 is a graph showing a relationship between a pulse width of a first drive pulse and a limit flying speed of an ink droplet.

FIG. 10 is a graph showing a relationship between an application cycle of a driving pulse, a flying speed of an ink droplet, and a volume of the ink droplet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink tube 3 Nozzle 4 Ink meniscus 7 Ink supply port 8 Substrate A, A1, A2 Pressure generating chamber H Ink droplet ejecting device P0 Drive pulse P1 First pulse P2 Second pulse

Claims (13)

[Claims] An electro-mechanical conversion means, a pressure generating chamber for generating pressure by operation of the electro-mechanical conversion means, a nozzle formed at one end of the pressure generating chamber, and emitting an ink droplet by the action of pressure. An ink supply unit that supplies ink to a pressure generating chamber; and an ink droplet ejecting apparatus that includes a driving pulse generating unit that drives the electromechanical conversion unit. A first driving pulse that generates a negative pressure in the pressure generating chamber. And a second drive pulse that subsequently generates a positive pressure in the pressure generation chamber,
At least one of the pulse width of the first drive pulse and the application cycle of the drive pulse is equal to the AL of the pressure generation chamber.
The drive pulse generation unit outputs the drive pulse set to be substantially deviated from an integral multiple of (a half of the resonance cycle of the pressure wave generated in the pressure generation chamber) by the electric pulse.
An ink droplet ejecting apparatus, wherein the ink droplet is ejected from the nozzle by applying to a mechanical conversion unit. 2. The ink droplet according to claim 1, wherein the driving pulse generating unit generates the driving pulse in which a pulse width of the first driving pulse is longer than the AL of the pressure generating chamber. Injection device. 3. The driving pulse generating means according to claim 1, wherein AL <W1
The apparatus according to claim 2, wherein the first drive pulse having a pulse width W1 of <1.3AL is generated. 4. The first driving pulse having a pulse width at which a critical flight speed at which a bubble can be stably emitted without causing entrainment of air bubbles from the nozzle is substantially maximized. 3. The ink droplet ejecting apparatus according to claim 2, wherein: 5. The driving pulse generating means according to claim 2, wherein said driving pulse generating means has a pulse width substantially twice as large as said first driving pulse.
5. A driving pulse according to claim 1, wherein
The ink droplet ejecting apparatus according to any one of claims 1 to 7. 6. The ink droplet according to claim 1, wherein the drive pulse generating means generates the second drive pulse having a pulse width of substantially 2AL. Injection device. 7. The ink droplet ejection apparatus according to claim 1, wherein the driving pulse generating means generates the driving pulse whose application cycle is set to be substantially deviated from an integral multiple of the AL. apparatus. 8. The driving pulse generating means substantially comprises n
8. The ink according to claim 7, wherein the driving pulse having the application cycle T set in a range of AL <T <(n + 2/3) AL (where n is an integer of 3 or more) is generated. Drop ejection device. 9. The driving pulse generator according to claim 2, wherein the driving pulse generating means has a pulse width substantially twice as large as the first driving pulse.
9. The ink droplet ejecting apparatus according to claim 7, wherein the driving pulse is generated. 10. The ink droplet ejecting apparatus according to claim 7, wherein the driving pulse generating means generates the second driving pulse having a pulse width of substantially 2AL. . 11. The electro-mechanical conversion means is provided with a first electrode and a second electrode, and the drive pulse generation means sends the first drive pulse to the first electrode and the second drive pulse to the second electrode. The ink droplet ejecting apparatus according to any one of claims 1 to 10, wherein the second driving pulse having the same polarity as the first driving pulse is applied to an electrode. 12. The driving pulse generator according to claim 1, wherein the driving pulse generator applies the first driving pulse and the second driving pulse each composed of a rectangular wave having a rise and fall time of 2 μs or less. Any one of ~ 11
Item 8. An ink droplet ejecting apparatus according to Item 1. 13. The driving pulse generating means applies the first driving pulse and the second driving pulse each consisting of a rectangular wave having a rise and fall time of 1/4 or less of a pulse width. The ink droplet ejection device according to any one of claims 1 to 11, wherein