JP3654299B2 - Ink droplet ejection device - Google Patents

Description

  The present invention relates to an ink droplet ejecting apparatus using an ink jet method.

  Conventionally, as an ink jet ink ejecting apparatus, the volume of the ink flow path is changed by deformation of piezoelectric ceramics, and when the volume decreases, ink in the ink flow path is ejected as droplets from the nozzle, and ink is introduced when the volume increases. An apparatus in which ink is introduced into an ink flow path from a mouth is known. In this type of recording head, a plurality of ink chambers separated by partition walls of piezoelectric ceramics are formed, and an ink supply means such as an ink cartridge is connected to one end of the plurality of ink chambers, and an ink is supplied to the other end. An ejection nozzle (hereinafter referred to as a nozzle) is provided, and by reducing the volume of the ink chamber by deformation of the partition wall according to print data, ink droplets are ejected from the nozzle to the recording medium, and characters, graphics, etc. Is recorded.

  In this type of ink jet type ink ejecting apparatus, a drop-on-demand type that ejects ink droplets is widely used due to good ejection efficiency and low running cost. As a drop-on-demand type, there is a shear mode type using a piezoelectric material as disclosed in Japanese Patent Laid-Open No. 63-247051. As shown in FIG. 12, this type of ink droplet ejecting apparatus 600 includes a bottom wall 601, a top wall 602, and a shear mode actuator wall 603 therebetween. The actuator wall 603 includes a lower wall 607 bonded to the bottom wall 601 and polarized in the direction of the arrow 611, and an upper wall 605 made of a piezoelectric material bonded to the top wall 602 and polarized in the direction of the arrow 609. It has become. A pair of actuator walls 603 form an ink chamber 613 therebetween, and a space 615 narrower than the ink chamber 613 is formed between the next pair of actuator walls 603.

  A nozzle plate 617 having nozzles 618 is fixed to one end of each ink chamber 613, and an ink supply source (not shown) is connected to the other end. Electrodes 619 and 621 are provided as metallization layers on both side surfaces of each actuator wall 603. Specifically, an electrode 619 is provided on the actuator wall 603 on the ink chamber 613 side, and an electrode 621 is provided on the actuator wall 603 on the space 615 side. Note that the surface of the electrode 619 is covered with an insulating layer 630 for insulating from the ink. The electrode 621 facing the space 615 is connected to the ground 623, and the electrode 619 provided in the ink chamber 613 is connected to a control device 625 that provides an actuator drive signal.

  Then, when the control device 625 applies a voltage to the electrode 619 of each ink chamber 613, each actuator wall 603 undergoes a piezoelectric thickness slip deformation in the direction of increasing the volume of the ink chamber 613. For example, as shown in FIG. 13, when a voltage E (V) is applied to the electrode 619c of the ink chamber 613c, electric fields in the directions of arrows 631 and 632 are generated on the actuator walls 603e and 603f, respectively, and the actuator walls 603e and 603f are generated. However, the piezoelectric thickness slips in the direction of increasing the volume of the ink chamber 613c. At this time, the pressure in the ink chamber 613c including the vicinity of the nozzle 618c decreases. The application state of the voltage E (V) is maintained for a one-way propagation time T in the ink chamber 613 of the pressure wave. In the meantime, ink is supplied from the ink supply source.

  The one-way propagation time T is a time required for the pressure wave in the ink chamber 613 to propagate in the longitudinal direction of the ink chamber 613, and the length L of the ink chamber 613 and the ink in the ink chamber 613 T = L / a depending on the speed of sound a.

  According to the pressure wave propagation theory, the pressure in the ink chamber 613 reverses and changes to a positive pressure after a time T or an odd multiple of the time since the application of the above voltage, but in accordance with this timing, the pressure in the ink chamber 613c is changed. The voltage applied to the electrode 621c is returned to 0 (V). Then, the actuator walls 603e and 603f return to the state before deformation (FIG. 12), and pressure is applied to the ink. At that time, the pressure turned positive and the pressure generated when the actuator walls 603e and 603f return to the state before deformation are added together, and a relatively high pressure is generated in the vicinity of the nozzle 618c of the ink chamber 613c. Ink droplets are ejected from the nozzle 618c. An ink supply path 626 that communicates with the ink chamber 613 is formed by a member 627 and a member 628.

  Conventionally, in this type of ink droplet ejecting apparatus 600, if the control is performed such as lowering the drive voltage in order to fly a small volume of ink droplets in order to increase the recording resolution, the ink droplet speed is decreased. There was a problem. It has also been proposed to add a low voltage level pulse after applying the ejection pulse and before ink ejection is completed so that a small volume droplet can be obtained without reducing the speed of the ink droplet. Yes.

  In the present invention, after a drive waveform for main ejection for one dot, a non-ejection pulse is added accompanying the drive waveform, thereby obtaining a small volume of ink droplets, and the size of the ink droplets. An ink droplet ejecting apparatus capable of improving gradation by arbitrarily changing the above is provided.

In order to achieve the above object, according to the first aspect of the present invention, a pressure wave is generated in an ink chamber by applying an ejection pulse signal to an actuator for changing the volume of the ink chamber filled with ink. In the ink droplet ejecting apparatus that ejects ink droplets from the nozzles, applying a first ejection pulse signal and a second ejection pulse signal as the ejection pulse signal in response to a 1-dot printing command, As the accompanying non-ejection pulse, an additional pulse signal for pulling back a part of the flying ink droplet by the ejection pulse signal to reduce the size of the ink droplet is used as the first ejection pulse signal and the second ejection pulse signal. It is one that applied between the first injection pulse signal, to generate a pressure wave in the ink chamber increases the volume of the ink chamber, the pressure Has a pulse width for decreasing the volume from the increased state and applying pressure to the ink after the passage of the time T or the odd multiple of the one-way propagation through the ink chamber, and the second ejection pulse signal is 0. The pulse width is 4T to 1.3T, the additional pulse signal has a pulse width of approximately 0.2T to 0.4T, and the falling edge of the first injection pulse signal and the rising edge of the additional pulse signal The time difference from the timing is 0.4T to 0.7T, the time difference between the fall of the additional pulse signal and the rise timing of the second injection pulse signal is 0.2T to 0.4T, and the first injection pulse signal, the peak value of the second injection pulse signal and the additional pulse signal is in the drop ejection device according to claim same der Rukoto.

Also, an ink droplet that ejects an ink droplet from a nozzle by applying a pressure wave to the ink chamber by applying an ejection pulse signal to an actuator for changing the volume of the ink chamber filled with ink, thereby applying pressure to the ink. In the ejection device, in response to a 1-dot printing command, a first ejection pulse signal and a subsequent second ejection pulse signal are applied as the ejection pulse signal, and the ejection pulse signal as a non-ejection pulse associated therewith is applied. the additional pulse signal to miniaturize the ink droplet is pulled back a portion of the flying ink droplets by, there is applied after the second injection pulse signal, increasing the volume of the ink chamber ink When the pressure wave is generated in the chamber and the time for which the pressure wave propagates almost one way in the ink chamber is T, the first ejection pulse signal rises. The time difference between the fall and the rising timing of the second injection pulse signal is 0.5T to 1.2T, the pulse width of the second injection pulse signal is 0.5T to 1.3T, and the second The time difference between the fall of the injection pulse signal and the rise timing of the additional pulse signal is 0.7T to 1.0T, and the peak values of the first injection pulse signal, the second injection pulse signal, and the additional pulse signal are the same. In the ink droplet ejecting apparatus,

  According to the present invention, the first and second ejection pulse signals and the additional pulse signal are applied as a one-dot printing command, and a part of the ink droplets that have jumped out of the nozzle by the ejection pulse signal is pulled back by the additional pulse signal. Reduce ink droplets. Furthermore, gradation can be improved by another ink droplet.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The configuration of the mechanical part in the ink droplet ejecting apparatus of the present embodiment is the same as that shown in FIG.

  An example of specific dimensions of the ink droplet ejecting apparatus 600 will be described. The length L of the ink chamber 613 is 7.5 mm. The nozzle 618 has a diameter of 40 μm on the ink droplet ejection side, a diameter of 72 μm on the ink chamber 613 side, and a length of 100 μm. The viscosity of the ink used in the experiment at 25 ° C. is about 2 mPa · s, and the surface tension is 30 mN / m. The ratio L / a (= T) between the speed of sound a in the ink in the ink chamber 613 and L was 8 μsec.

  Next, various drive waveforms applied to the electrode 619 in the ink chamber 613 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an ejection pulse signal (drive waveform) for making a small droplet, which is a premise of the present invention. The drive waveform in FIG. 1 is a pulse for printing one dot, and an ejection pulse signal A for ejecting an ink droplet, followed by one of the ink droplets ejected from the nozzle by the ejection pulse signal A. Non-ejection pulse that is additionally applied at a timing at which the portion can be pulled back, and has an additional pulse signal (droplet miniaturization pulse) B that has a smaller pulse width than the ejection pulse signal A and makes the flying ink droplets smaller. It consists of. Both the ejection pulse signal A and the additional pulse signal B have the same peak value (voltage value) (for example, 20 V).

  The wave width of the ejection pulse signal A is a value that coincides with the ratio L / a (= T) between the sound speed a and the L in the ink in the ink chamber 613 or an odd multiple thereof (a value unique to the head). The time difference between the falling edge of the ejection pulse signal A and the rising timing of the additional pulse signal B is 0.55T. The wave width of the additional pulse signal B is 0.35T. The additional pulse signal B does not eject ink droplets at this wave width. Note that the pulse period when the next dot is continuously printed is 100 μsec when the driving frequency is 10 kHz. With this drive waveform, as will be described later, the injection may become unstable at high temperatures.

  FIG. 2 shows drive waveforms according to Reference Example 1 of the present invention. The drive waveform is equivalent to that shown in FIG. 1 and is an ejection pulse signal A and a first additional pulse signal (hereinafter referred to as droplet miniaturization pulse) B. The second additional pulse signal (hereinafter referred to as injection stabilization pulse) C is added.

  The ejection pulse signal A has the same pulse width as the signal A in FIG. The droplet miniaturization pulse B and the ejection stabilization pulse C each have a pulse width of 0.2T to 0.4T with respect to the ejection pulse signal A, preferably the pulse B is 0.35T and the pulse C is 0.3T. In addition, the time difference between the fall of the ejection pulse signal A and the rise timing of the droplet miniaturization pulse B is set to 0.4T to 0.7T, preferably 0.55T. The time difference from the rising timing of the activating pulse C is set to 0.9T to 1.3T, preferably 1.1T. The effect of adding the injection stabilization pulse C will be described later with reference to FIG. 11 in contrast to the case of the drive waveform of FIG. These numerical values and numerical ranges are obtained by experiments.

  FIG. 3 shows drive waveforms according to the first embodiment of the present invention. This drive waveform is the same as that in FIG. 2 described above, and the ejection pulse signal A is divided into two ejection pulses A1 and A2, and the droplet miniaturization pulse B is located between these ejection pulses A1 and A2. Is different. Compared with that of FIG. 2, by dividing the ejection pulse into two, the droplet volume can be arbitrarily adjusted, and the gradation can be improved. The ejection pulse A1 has the same pulse width as the ejection pulse A in FIG. 1, and the ejection pulse A2 has a pulse width of 0.4T to 1.3T, preferably 0.5T. The time difference between the fall of the ejection pulse signal A1 and the rise timing of the droplet miniaturization pulse B is 0.4T to 0.7T, preferably 0.55T, as in FIG. The pulse width is 0.2T to 0.4T, preferably 0.35T. The time difference between the falling edge of the droplet miniaturization pulse B and the rising timing of the ejection pulse signal A2 is 0.2T to 0.4T, preferably 0.35T. The time difference between the falling edge of the injection pulse signal A2 and the rising timing of the injection stabilization pulse C is 2.25T to 2.45T, or 1.7T to 1.95T, preferably 2.35T. The pulse width of C is 0.3T to 0.7T, or 1.3T to 1.8T, preferably 0.5T. The droplet volume by this driving waveform is 40 pl (picoliter).

  FIG. 4 shows drive waveforms according to the second embodiment of the present invention. This driving waveform is different from that shown in FIG. 3 in that the droplet miniaturization pulse B and the ejection stabilization pulse C are positioned after the two ejection pulses A1 and A2 of the ejection pulse signal A. Compared to that of FIG. 2, the same operational difference as that of FIG. 3 is obtained. The time difference between the falling edge of the injection pulse signal A1 and the rising timing of the injection pulse signal A2 is 0.5T to 1.2T, preferably 0.8T, and the pulse width of the injection pulse signal A2 is 0.5T to 1. 3T, preferably 0.8T. The time difference between the falling edge of the ejection pulse signal A2 and the rising timing of the droplet miniaturization pulse B is 0.7T to 1.0T, preferably 0.85T. The pulse width of the droplet miniaturization pulse B is 0. 2T to 0.4T, preferably 0.35T. The time difference between the falling edge of the droplet miniaturization pulse B and the rising timing of the ejection stabilization pulse C is 1.0T to 1.2T, or 0.45T to 0.7T, preferably 1.1T. The pulse width of the activating pulse C is 0.3T to 0.7T, or 1.3T to 1.8T, preferably 0.5T. The droplet volume by this driving waveform is also 40 pl.

  FIG. 5 shows drive waveforms according to Reference Example 2 of the present invention. This drive waveform basically has the same form as in FIG. 2, and the pulse width of the ejection pulse signal is 1T or an odd multiple thereof in the above embodiment, but the drive waveform of this embodiment is the ejection pulse signal. A pulse width Wa of A is set between 0.5T and 1.5T, the time difference d between the falling edge of the ejection pulse signal A and the rising timing of the droplet miniaturization pulse B, and the pulse of the droplet miniaturization pulse B By setting the width Wb to a predetermined value, it is possible to prevent the occurrence of splashing or defective ejection during ink ejection. Splashing is a phenomenon in which ink scatters without becoming one droplet. FIG. 6 shows an experimental result obtained by changing the combination of the time difference d and the pulse width Wb when the pulse width Wa of the injection pulse signal A is changed from 0.5T to 1.5T. There was no turbulence or splash, and a cross indicates that splash or defective ejection occurred. Accordingly, the time difference d between the falling edge of the ejection pulse signal A and the rising timing of the droplet miniaturization pulse B is 0.3T to 1.0T, and the pulse width Wb of the droplet miniaturization pulse B is 0.3T to 1.T. It can be seen that printing failure does not occur if 0T is set and the sum of the time difference d and the pulse width Wb falls within 0.7T to 1.3T. The time difference between the falling edge of the droplet miniaturization pulse B and the rising timing of the ejection stabilization pulse C is 0.7T to 1.3T, preferably 0.9T, and the pulse width of the ejection stabilization pulse C is 0.2T to 0.4T, preferably 0.35T.

  FIGS. 7 and 8 are provided for comparison with the present invention, and both show drive waveforms by single pulse and multi-pulse that the applicant has proposed previously. The single pulse drive waveform in FIG. 7 includes an injection pulse signal A and an injection stabilization pulse C. The droplet volume by this driving waveform is 30 pl. The multi-pulse drive waveform in FIG. 8 includes injection pulses A1 and A2 and an injection stabilization pulse C. The droplet volume by this driving waveform is 50 pl.

  Next, an embodiment of a control device for realizing the drive waveforms as shown in FIGS. 2 to 5 will be described with reference to FIGS. The control device 625 shown in FIG. 9 includes a charging circuit 182, a discharging circuit 184, and a pulse control circuit 186. The piezoelectric material of the actuator wall 603 and the electrodes 619 and 621 are equivalently represented by a capacitor 191. 191A and 191B are terminals thereof.

  The input terminals 181 and 182 are input terminals for inputting pulse signals for setting voltages applied to the electrodes 619 in the ink chamber 613 to E (V) and 0 (V), respectively. The charging circuit 182 includes resistors R101, R102, R103, R104, R105, and transistors TR101, TR102.

  When an ON signal (+5 V) is input to the input terminal 181, the transistor TR 101 becomes conductive through the resistor R 101, and current flows from the positive power source 187 through the resistor R 103 to the emitter from the collector of the transistor TR 101. Therefore, the voltage division across the resistors R104 and R105 connected to the positive power supply 187 increases, the current flowing through the base of the transistor TR102 increases, and the emitter and collector of the transistor TR102 are conducted. A voltage of 20 (V) from the positive power supply 187 is applied to the capacitor 191 and the terminal 191A via the collector and emitter of the transistor TR102 and the resistor R120.

  Next, the discharging circuit 184 will be described. The discharging circuit 184 includes resistors R106 and R107 and a transistor TR103. When an ON signal (+ 5V) is input to the input terminal 182, the transistor TR103 is turned on via the resistor R106, and the resistor R120 side terminal 191A of the capacitor 191 is grounded via the resistor R120. Therefore, the electric charge applied to the actuator wall 603 of the ink chamber 613 shown in FIGS. 12 and 13 is discharged.

  Next, the pulse control circuit 186 that generates pulse signals input to the input terminal 181 of the charging circuit 182 and the input terminal 182 of the discharging circuit 184 will be described. The pulse control circuit 186 is provided with a CPU 110 that performs various arithmetic processes. The CPU 110 generates an on / off signal according to the control program and timing of the RAM 112 and the pulse control circuit 186 that store print data and various data. A ROM 114 storing sequence data is connected. Here, the ROM 114 is provided with an ink droplet ejection control program storage area 114A and a drive waveform data storage area 114B as shown in FIG. . Therefore, the drive waveform sequence data is stored in the drive waveform data storage area 114B.

  Although not shown, the control device 625 includes means for detecting a temperature related to ink such as an ambient temperature. In the control program storage area 114A, as shown in FIG. 14, the CPU 110 determines whether the temperature is equal to or higher than a predetermined value (S1), and is stored in the waveform data storage area 114B based on the determination result. A program for determining whether or not to add the first and second additional pulses B and C (droplet miniaturization pulse and stabilization pulse) to the ejection pulse signal A (S2, S3) is stored.

  Further, the CPU 110 is connected to an I / O bus 116 for exchanging various data, and a print data receiving circuit 118 and pulse generators 120 and 122 are connected to the I / O bus 116. The output of the pulse generator 120 is connected to the input terminal 181 of the charging circuit 182, and the output of the pulse generator 122 is connected to the input terminal 182 of the discharging circuit 184.

  The CPU 110 controls the pulse generators 120 and 122 according to the sequence data stored in the drive waveform data recording area 114B of the ROM 114. Therefore, by storing the various patterns of the timing in the drive waveform data storage area 114B in the ROM 114 in advance, the drive pulse having the drive waveform shown in FIG.

  Note that the pulse generators 120 and 122, the charging circuit 182 and the discharging circuit 184 are provided in the same number as the number of nozzles. In the present embodiment, the control of one nozzle has been described as a representative, but the same control applies to the control of other nozzles.

Next, test results of ink droplet ejection under various temperature conditions (ink droplet velocity) when driven with the pulse having the drive waveform shown in FIG. 2 of the reference example and when driven with the pulse with the drive waveform shown in FIG. M / s) is shown in FIGS. 11 (a) and 11 (b). The numbers (1 to 10) in the upper part of each figure indicate the dot numbers when driven at a predetermined frequency (16 kHz), the numbers 5 to 40 in the leftmost column indicate the temperature (° C.), and here, 5 ( After 1 to 5) continuous dots, pause for 1 dot (No. 6), and then again, after 2 consecutive dots (7, 8), pause for 1 dot (No. 9), and then One dot (No. 10) was ejected. A pulse having the driving waveform shown in FIG. 2 or 1 is applied to each dot. A numerical value in parentheses adjacent to the temperature is a voltage value applied when ejecting a droplet at 8 m / s at each temperature.

  As can be seen from FIG. 11, as the temperature increases, the second droplet velocity of two consecutive dots after a pause after successive dots has a tendency to decrease. In particular, the drive waveform of FIG. In the case where only the droplet miniaturization pulse B is applied as shown in FIG. This is presumably because the ink viscosity decreases in the high temperature range and the meniscus vibration cannot be suppressed. In particular, when the droplet miniaturization pulse B rises in a state where the ink meniscus is retracted from the nozzle, the meniscus further tends to retract, and the ejection speed is further decreased. As a result, the ink landing position is shifted, and the print quality is deteriorated. On the other hand, since the injection stabilization pulse C is further added as shown in the drive waveform of FIG. 2, the speed reduction at the portion corresponding to the above is suppressed, and the above problem is solved. In the measurement of FIG. 11, the droplet miniaturization pulse B and the ejection stabilization pulse C are added to all the dots regardless of the temperature. As shown in the above, it should be added only when the temperature is higher than a predetermined temperature (for example, 25 ° C.). X in FIG. 11 is an unmeasured part. In the low temperature range where the ink viscosity is relatively high, the load of the control device 625 is reduced by the absence of the additional pulses B and C, and the ejection of the ejection pulse A can be reduced to enable ejection at a high cycle. .

  As shown in FIG. 1 or FIG. 2, a state in which the droplet can be miniaturized by adding the droplet miniaturization pulse B to the ejection pulse signal A will be described. The volume of the ink chamber temporarily increases, the ink meniscus temporarily retracts inward of the nozzle, and then the ejection pulse signal A falls after the passage of time for the pressure wave to propagate one way through the ink chamber. As the ink decreases from the increased state to the natural state, ink tends to be ejected from the nozzles. At this time, when the droplet miniaturization pulse B is applied, a part of the ink droplet ejected from the nozzle becomes a meniscus pulled back, so that the ink droplet ejected from the nozzle is miniaturized. In this way, it is possible to obtain ejection of a small volume of ink droplets by simply adding a non-ejection pulse after the main driving waveform without changing the driving voltage and therefore without increasing the cost.

Although one embodiment has been described above, the present invention is not limited to this. For example, in the above-described reference example , the one in which the droplet miniaturization pulse B and the ejection stabilization pulse C are always added to one ejection pulse A which is the main driving signal is shown. However, when there are no dots before and after the dot, For the dots, only one ejection pulse A, which is the main drive signal, may be used. In addition, the ink droplet ejecting apparatus 600 is not limited to the configuration of the above-described embodiment, and a piezoelectric material whose polarization direction is reversed may be used.

  In this embodiment, the air chambers 615 are provided on both sides of the ink chamber 613. However, the ink chambers may be adjacent to each other without providing the air chamber. Furthermore, in this embodiment, a shear mode type actuator is used. However, a piezoelectric material may be stacked and a pressure wave may be generated by deformation in the stacking direction. Anything that generates waves can be used.

It is a figure which shows the ejection pulse signal (driving waveform) for setting it as the small droplet which is a premise of this invention. It is a figure which shows the drive waveform by the reference example 1 of this invention. It is a figure which shows the drive waveform by Example 1 of this invention. It is a figure which shows the drive waveform by Example 2 of this invention. It is a figure which shows the drive waveform by the reference example 2 of this invention. It is a figure which shows the experimental result when changing the time difference of the fall of an ejection pulse signal and the rise timing of a droplet miniaturization pulse, and the value of the pulse width of a droplet miniaturization pulse. It is a figure which shows the single pulse drive waveform which the present applicant has proposed previously. It is a figure which shows the multipulse drive waveform which the present applicant has proposed previously. It is a figure which shows the drive circuit of an ink droplet ejecting apparatus. It is a figure which shows the memory area of ROM of the control apparatus of an ink droplet ejecting apparatus. (A) is a diagram showing ink droplet ejection speeds under various temperature conditions when driven by pulses of the drive waveform shown in FIG. 2 of the present embodiment, and (b) is driven by pulses of the drive waveform of FIG. It is a figure which shows the ink droplet jetting speed on various temperature conditions at the time of doing. (A) is a longitudinal sectional view of an ink ejection portion of the recording head, and (b) is a transverse sectional view thereof. FIG. 6 is a longitudinal sectional view illustrating an operation of an ink ejecting portion of a recording head. It is a flowchart explaining the control content of ROM of the control apparatus of the ink droplet ejection apparatus of this invention.

Explanation of symbols

A1 jet pulse signal A2 jet pulse signal B first additional pulse signal (droplet miniaturization pulse)
600 Inkjet head 603 Actuator wall 613 Ink chamber 625 Control device

Claims (2)

An ink droplet ejecting apparatus that generates a pressure wave in an ink chamber by applying an ejection pulse signal to an actuator for changing the volume of the ink chamber filled with ink, thereby applying pressure to the ink and ejecting ink droplets from a nozzle. In
In response to a 1-dot printing command, a first ejection pulse signal and a second ejection pulse signal are applied as the ejection pulse signal, and an associated non-ejection pulse is used as one of the flying ink droplets by the ejection pulse signal. Applying an additional pulse signal for pulling back the portion to reduce the size of the ink droplet between the first ejection pulse signal and the second ejection pulse signal ,
The first ejection pulse signal increases the volume of the ink chamber to generate a pressure wave in the ink chamber, and after the time T when the pressure wave propagates almost one way in the ink chamber or an odd multiple thereof, The second ejection pulse signal has a pulse width of 0.4T to 1.3T, and has a pulse width for decreasing the volume from the increased state and applying pressure to the ink;
The additional pulse signal has a pulse width of approximately 0.2T to 0.4T, and a time difference between the falling edge of the first injection pulse signal and the rising timing of the additional pulse signal is 0.4T to 0.7T. The time difference between the fall of the additional pulse signal and the rise timing of the second injection pulse signal is 0.2T to 0.4T,
It said first injection pulse signal, the ink droplet ejection device crest value of the second injection pulse signal and the additional pulse signal, wherein the same der Rukoto. An ink droplet ejecting apparatus that generates a pressure wave in an ink chamber by applying an ejection pulse signal to an actuator for changing the volume of the ink chamber filled with ink, thereby applying pressure to the ink and ejecting ink droplets from a nozzle. In
In response to a one-dot printing command, a first ejection pulse signal and a second ejection pulse signal following the first ejection pulse signal are applied as the ejection pulse signal, and a flying ink droplet based on the ejection pulse signal is used as an accompanying non-ejection pulse. the ink droplet is pulled back a portion of the additional pulse signal to miniaturize, there is applied after the second injection pulse signal,
When the volume of the ink chamber is increased to generate a pressure wave in the ink chamber and the time for the pressure wave to propagate almost one way in the ink chamber is T, the falling edge of the first ejection pulse signal and the second The time difference from the rising timing of the injection pulse signal is 0.5T to 1.2T, the pulse width of the second injection pulse signal is 0.5T to 1.3T, and the second injection pulse signal The time difference between the fall and the rise timing of the additional pulse signal is 0.7T to 1.0T.
It said first injection pulse signal, wherein the to Louis ink droplet ejecting device that the peak value of the second injection pulse signal and the additional pulse signal are the same.

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