JP2020044667A - Liquid jet head, liquid jet recording device and driving signal generating system - Google Patents

Abstract

To provide a liquid jet head, a liquid jet recording device and a driving signal generating system which can improve convenience for a user.SOLUTION: The liquid jet head according to an embodiment in the disclosure comprises: a jet part having a plurality of nozzles for jetting liquid; a driving part that jets liquid through the nozzles by applying a driving signal having one or a plurality of pulses to the jet part; a sound measuring part that has a transmitter that transmits an ultrasonic sound signal into liquid and a receiver that receives the ultrasonic sound signal from the inside of liquid; and a signal generating part that generates the driving signal. The signal generating part sets the pulse on the basis of comparison of the signals between the transmitter and the receiver in the sound measuring part, and generates the driving signal using the set pulse.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a liquid ejection head, a liquid ejection recording device, and a drive signal generation system.

  2. Related Art Liquid ejecting recording apparatuses having a liquid ejecting head are used in various fields, and various types of liquid ejecting heads have been developed (for example, see Patent Document 1).

JP 2014-151646 A

  In such a liquid ejecting head, it is required to improve convenience for a user. It is desirable to provide a liquid ejection head, a liquid ejection recording device, and a drive signal generation system that can improve the convenience for the user.

  A liquid ejecting head according to an embodiment of the present disclosure includes an ejecting unit having a plurality of nozzles for ejecting a liquid, and applying a drive signal having one or a plurality of pulses to the ejecting unit, so that the nozzle is ejected from the nozzle. A drive unit for injecting the liquid, a transmitter for transmitting an ultrasonic acoustic signal into the liquid, and a receiver for receiving the ultrasonic acoustic signal from within the liquid; And a signal generation unit that generates The signal generation unit sets a pulse based on a comparison between signals at the transmitter and the receiver in the acoustic measurement unit, and generates the drive signal using the set pulse.

  A liquid jet recording apparatus according to an embodiment of the present disclosure includes the liquid jet head according to the embodiment of the present disclosure.

  A drive signal generation system according to an embodiment of the present disclosure is a system that generates a drive signal having one or more pulses applied to an ejection unit having a plurality of nozzles for ejecting liquid, A transmitter that transmits an ultrasonic acoustic signal into the liquid, a receiver that receives the ultrasonic acoustic signal from within the liquid, and a signal generating unit that generates the drive signal. It is provided. The signal generation unit sets a pulse based on a comparison between signals at the transmitter and the receiver in the acoustic measurement unit, and generates a drive signal using the set pulse.

  According to the liquid ejection head, the liquid ejection recording apparatus, and the drive signal generation system according to an embodiment of the present disclosure, it is possible to improve the convenience for the user.

FIG. 1 is a schematic perspective view illustrating a schematic configuration example of a liquid jet recording apparatus according to an embodiment of the present disclosure. FIG. 2 is a schematic diagram illustrating a schematic configuration example of a liquid ejecting head illustrated in FIG. 1. FIG. 3 is a block diagram illustrating a detailed configuration example of a liquid ejecting head illustrated in FIG. 2. FIG. 4 is a timing chart schematically illustrating a configuration example of a drive signal. FIG. 4 is a block diagram illustrating a detailed configuration example and the like of a signal generation unit illustrated in FIG. 3. FIG. 6 is a block diagram illustrating a detailed configuration example of an analysis signal generation section illustrated in FIG. 5. FIG. 4 is a block diagram illustrating a schematic configuration example of a liquid jet recording apparatus according to a comparative example. 5 is a flowchart illustrating a process of generating a drive signal according to the embodiment; FIG. 9 is a timing chart illustrating waveform examples of various signals during the generation processing of the drive signal illustrated in FIG. 8. FIG. 3 is a schematic diagram for explaining an outline of a pulse width setting method and the like. 9 is a block diagram illustrating a schematic configuration example of a liquid jet recording apparatus according to Modification Example 1. FIG. 13 is a block diagram illustrating a schematic configuration example of a liquid jet recording apparatus according to Modification Example 2. FIG.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be made in the following order.
1. Embodiment (an example in which an acoustic measurement unit and a signal generation unit are provided in a liquid ejection head)
2. Modified example Modified example 1 (example in which a part of the acoustic measurement unit is provided in the ejection unit)
Modification 2 (example in which an acoustic measurement unit and a signal generation unit are provided outside the liquid jet head)
3. Other modifications

<1. Embodiment>
[A. Overall Configuration of Printer 1]
FIG. 1 is a perspective view schematically illustrating a schematic configuration example of a printer 1 as a liquid jet recording apparatus according to an embodiment of the present disclosure. The printer 1 is an ink jet printer that records (prints) images, characters, and the like on recording paper P as a recording medium by using ink 9 described below.

  As shown in FIG. 1, the printer 1 includes a pair of transport mechanisms 2a and 2b, an ink tank 3, an inkjet head 4, an ink supply pipe 50, and a scanning mechanism 6. These members are accommodated in a housing 10 having a predetermined shape. In each drawing used in the description of this specification, the scale of each member is appropriately changed in order to make each member a recognizable size.

  Here, the printer 1 corresponds to a specific example of a “liquid ejection recording device” in the present disclosure, and the inkjet head 4 (the later-described inkjet heads 4Y, 4M, 4C, and 4K) is a “liquid ejecting head” in the present disclosure. Corresponds to one specific example. The ink 9 corresponds to a specific example of “liquid” in the present disclosure.

  As shown in FIG. 1, each of the transport mechanisms 2a and 2b is a mechanism that transports the recording paper P along the transport direction d (X-axis direction). Each of these transport mechanisms 2a and 2b has a grid roller 21, a pinch roller 22, and a drive mechanism (not shown). This drive mechanism is a mechanism that rotates the grid roller 21 around the axis (rotates in the ZX plane), and is configured by, for example, a motor.

(Ink tank 3)
The ink tank 3 is a tank that stores the ink 9 therein. In this example, as shown in FIG. 1, the ink tanks 3 individually store the four color inks 9 of yellow (Y), magenta (M), cyan (C), and black (K). There are different types of tanks. That is, an ink tank 3Y containing yellow ink 9, an ink tank 3M containing magenta ink 9, an ink tank 3C containing cyan ink 9, and an ink tank 3K containing black ink 9 are provided. Is provided. These ink tanks 3Y, 3M, 3C, and 3K are arranged in the housing 10 along the X-axis direction.

  The ink tanks 3Y, 3M, 3C, and 3K have the same configuration except for the color of the ink 9 to be stored.

(Inkjet head 4)
The inkjet head 4 is a head that records (prints) images, characters, and the like by ejecting (discharging) droplet-shaped ink 9 from a plurality of nozzles (nozzle holes Hn) described below onto the recording paper P. . In this example, as shown in FIG. 1, four types of heads which individually eject the four color inks 9 stored in the ink tanks 3Y, 3M, 3C, and 3K, respectively, are also used as the ink jet heads 4. Is provided. That is, an inkjet head 4Y that ejects the yellow ink 9, an inkjet head 4M that ejects the magenta ink 9, an inkjet head 4C that ejects the cyan ink 9, and an inkjet head 4K that ejects the black ink 9. Is provided. These inkjet heads 4Y, 4M, 4C, and 4K are arranged in the housing 10 along the Y-axis direction.

  The ink-jet heads 4Y, 4M, 4C, and 4K have the same configuration except for the color of the ink 9 to be used. A detailed configuration example of the inkjet head 4 will be described later (FIGS. 2 to 6).

  The ink supply pipe 50 is a pipe to which the ink 9 is supplied from the inside of the ink tank 3 to the inside of the inkjet head 4. The ink supply tube 50 is formed of, for example, a flexible hose having a degree of flexibility that can follow the operation of the scanning mechanism 6 described below.

(Scanning mechanism 6)
The scanning mechanism 6 is a mechanism that causes the inkjet head 4 to scan along the width direction (Y-axis direction) of the recording paper P. As shown in FIG. 1, the scanning mechanism 6 includes a pair of guide rails 61a and 61b extending along the Y-axis direction, and a carriage 62 movably supported by the guide rails 61a and 61b. And a drive mechanism 63 for moving the carriage 62 along the Y-axis direction.

  The drive mechanism 63 includes a pair of pulleys 631a and 631b disposed between the guide rails 61a and 61b, an endless belt 632 wound between the pulleys 631a and 631b, and a drive motor 633 for driving the pulley 631a to rotate. And The four types of inkjet heads 4Y, 4M, 4C, and 4K described above are arranged on the carriage 62 along the Y-axis direction.

  The scanning mechanism 6 and the above-described transport mechanisms 2a and 2b constitute a moving mechanism for relatively moving the inkjet head 4 and the recording paper P.

[B. Detailed configuration of inkjet head 4]
Subsequently, a detailed configuration example of the inkjet head 4 will be described with reference to FIGS.

  Here, FIG. 2 schematically illustrates a schematic configuration example of the inkjet head 4. FIG. 3 is a block diagram showing a detailed configuration example of the inkjet head 4 shown in FIG.

  As shown in FIGS. 2 and 3, the inkjet head 4 includes a nozzle plate 41, an actuator plate 42, a temperature detection unit 45, an acoustic measurement unit 47, a signal generation unit 48, and a drive unit 49.

  Note that the nozzle plate 41 and the actuator plate 42 correspond to a specific example of the “ejection unit” in the present disclosure. In addition, the signal generation unit 48 corresponds to a specific example of a “drive signal generation system” in the present disclosure.

(Nozzle plate 41)
The nozzle plate 41 is a plate made of a film material such as polyimide or a metal material, and has a plurality of nozzle holes Hn for ejecting the ink 9 as shown in FIGS. 2 and 3 (FIG. 2). , See dashed arrows in FIG. 3). These nozzle holes Hn are formed side by side at predetermined intervals on a straight line (along the X-axis direction in this example). Each nozzle hole Hn corresponds to a specific example of “nozzle” in the present disclosure.

(Actuator plate 42)
The actuator plate 42 is a plate made of a piezoelectric material such as PZT (lead zirconate titanate). The actuator plate 42 has a plurality of channels (not shown). These channels are portions that function as pressure chambers for applying pressure to the ink 9, and are arranged side by side at predetermined intervals so as to be parallel to each other. Each channel is respectively defined by a driving wall (not shown) made of a piezoelectric material, and has a concave groove portion in a sectional view.

  Such channels include a discharge channel for discharging the ink 9 (discharge channel Ce described later: see FIG. 10) and a dummy channel (non-discharge channel) for not discharging the ink 9. In other words, the ejection channel is filled with the ink 9 while the dummy channel is not filled with the ink 9. Each discharge channel communicates with the nozzle hole Hn in the nozzle plate 41, while each dummy channel does not communicate with the nozzle hole Hn. These ejection channels and dummy channels are alternately arranged along a predetermined direction.

  Driving electrodes (not shown) are provided on opposing inner surfaces of the driving wall. The drive electrode includes a common electrode (common electrode) provided on the inner surface facing the ejection channel, and an active electrode (individual electrode) provided on the inner surface facing the dummy channel. These drive electrodes and a drive circuit on a drive board (not shown) are electrically connected via a plurality of lead electrodes formed on a flexible board (not shown). Thereby, a drive voltage Vd (drive signal Sd) described later is applied to each drive electrode from a drive circuit including a drive unit 49 described later via the flexible substrate.

(Temperature detector 45)
The temperature detector 45 detects the temperature (actuator temperature Tpzt) in the vicinity of the actuator plate 42 in the inkjet head 4 as shown in FIG. The actuator temperature Tpzt detected by the temperature detection unit 45 in this manner is output to a signal generation unit 48 described later.

(Acoustic measurement unit 47)
As shown in FIG. 3, the acoustic measurement unit 47 performs a predetermined measurement (acoustic measurement) on the ink 9 flowing in the ink supply pipe 50 described above, and includes an ultrasonic transmitter 471 and an ultrasonic receiver. 472.

  As shown in FIG. 3, the ultrasonic transmitter 471 is a device that transmits an ultrasonic acoustic signal Sac toward the ink 9 as an acoustic signal Sacout. The transmission of such an acoustic signal Sacout is performed, for example, based on an electric signal output from the signal generation unit 48 using electro-mechanical conversion (see FIG. 3).

  The ultrasonic receiver 472 is a device that receives an acoustic signal Sac of the ultrasonic wave from the ink 9 as shown in FIG. Specifically, the ultrasonic receiver 472 receives, as the acoustic signal Sacin, the acoustic signal Sac output from the ultrasonic transmitter 471 and traveling through the ink 9. The reception of such an acoustic signal Sacin is performed using, for example, mechanical-electrical conversion, and the acoustic signal Sacin thus obtained is output to the signal generation unit 48. (See FIG. 3).

  Incidentally, in the present embodiment, each of such acoustic signals Sac (Sacout, Sacin) is configured using a sine wave, for example, as described later (see FIG. 9). By configuring the acoustic signal Sac using such a sine wave, the frequency component in the acoustic signal Sac becomes single, and therefore, for example, a pulse-like waveform (rectangular wave) having a non-single frequency component is used. As compared with the case where the acoustic signal Sac is configured as described above, the result is as follows. That is, for example, it is not necessary to separate frequency components such as Fast Fourier Transform (FFT), so that the analysis signal generation unit 482 in the signal generation unit 48, which will be described later, simplifies the analysis process. It has become possible.

  Here, such an ultrasonic transmitter 471 and an ultrasonic receiver 472 respectively correspond to specific examples of “transmitter” and “receiver” in the present disclosure.

(Signal generator 48)
The signal generation unit 48, which will be described in detail later, performs one or more pulses (pulse width) in the drive signal Sd based on the comparison between the signals from the ultrasonic transmitter 471 and the ultrasonic receiver 472 in the acoustic measurement unit 47 described above. Wp, voltage value Vp), and the drive signal Sd is generated using the set pulse.

  Here, FIG. 4A to FIG. 4C each schematically show a configuration example of such a drive signal Sd in a timing chart. In FIGS. 4A to 4C, the horizontal axis represents time t, and the vertical axis represents the drive voltage Vd (positive voltage in this example) of the drive signal Sd.

  First, the drive signal Sd shown in FIG. 4A has one pulse (pulse Pa), which is an example of a so-called “one drop”. The pulse Pa is an ON period provided between the rising timing and the falling timing, and has a pulse width Wpa1 and a voltage value Vp1 as an example of the above-described pulse width Wp and voltage value Vp.

  On the other hand, the drive signal Sd shown in FIG. 4B has the following two pulses (pulses Pa and Pb) as pulses to which a so-called “multi-pulse method” is applied (so-called “2 drop”). Example). That is, two pulses Pa and Pb are provided as such a pulse (ON period). Note that an OFF period (“OFF1”) is provided between these two pulses Pa and Pb. In addition, as an example of the above-described pulse width Wp and voltage value Vp, pulse Pa has pulse width Wpa2 and voltage value Vp2, and pulse Pb has pulse width Wpb2 and voltage value Vp2.

  Similarly, the drive signal Sd shown in FIG. 4C has the following three pulses (pulses Pa, Pb, and Pc) as pulses to which the above-described “multi-pulse method” is applied (so-called “pulse Pa”, “Pb”, “Pc”). Example of "3 drop"). That is, three pulses Pa, Pb, and Pc are provided as such a pulse (ON period). An OFF period (“OFF1”) is provided between the pulses Pa and Pb, and an OFF period (“OFF2”) is provided between the pulses Pb and Pc. As an example of the above-described pulse width Wp and voltage value Vp, pulse Pa has pulse width Wpa3 and voltage value Vp3, pulse Pb has pulse width Wpb3 and voltage value Vp3, and pulse Pc has pulse width Wpc3 and voltage value Vp3. It has a voltage value Vp3.

  Each of the pulses Pa, Pb, and Pc in the drive signal Sd is a positive pulse that causes the above-described ejection channel to expand during a high (High) state and causes the ejection channel to contract during a low (Low) state. It has become.

  Here, although the details will be described later, the signal generation unit 48 obtains the pulse width Wp and the voltage value Vp in such pulses (pulses Pa, Pb, Pc), and has the obtained pulse width Wp and voltage value Vp. The drive signal Sd is generated using a pulse. The details of the process of generating the drive signal Sd by the signal generation unit 48 will be described later (FIGS. 8 to 10).

  Here, the above-described voltage value Vp corresponds to a specific example of “peak value” in the present disclosure. The above-mentioned “pulse” has a concept including not only a rectangular wave as shown in FIG. 4 but also a waveform such as a trapezoidal wave, a triangular wave, and a step wave, and so on.

(Drive unit 49)
The drive unit 49 applies the above-described drive voltage Vd (drive signal Sd) to the actuator plate 42 to expand or contract the above-described ejection channel, thereby ejecting the ink 9 from each nozzle hole Hn (ejection). (See FIG. 2 and FIG. 3). Specifically, the driving section 49 performs such an ejection operation using the driving signal Sd generated by the signal generation section 48 described above.

[C. Detailed Configuration of Signal Generation Unit 48]
Subsequently, a detailed configuration example of the above-described signal generation unit 48 will be described with reference to FIGS. FIG. 5 is a block diagram showing a detailed configuration example of the signal generation unit 48 together with the above-described sound measurement unit 47. FIG. 6 is a block diagram illustrating a detailed configuration example of the analytic signal generation unit 482 (described later) illustrated in FIG.

  As shown in FIG. 5, the signal generator 48 includes a bandpass filter 481, an analysis signal generator 482, an amplitude signal generator 483, a counter circuit 484, an acoustic signal generator 485, an attenuation calculator 486, and a waveform setting unit. 487.

(Band pass filter 481)
As shown in FIG. 5, the band pass filter 481 performs a predetermined band pass filter process on the acoustic signal Sacin obtained from the ultrasonic receiver 472. This band pass filter processing is a filter processing for suppressing noise in the acoustic signal Sacin, and for example, a sine wave band used for measurement by the acoustic measurement unit 47 is a pass band. The acoustic signal Sacin after such band pass filter processing is output to the analysis signal generation unit 482 as a signal S0 (sine wave signal).

(Analysis signal generator 482)
The analytic signal generation section 482 performs a predetermined analytic process on the signal S0 to output two analytic signals S1a and S1b, respectively, as shown in FIG. In this example, the analysis signal S1b is a signal whose phase is delayed by 90 ° with respect to the analysis signal S1b.

  The analytic signal generator 482 includes a Hilbert transform circuit 482a and a delay circuit 482b as shown in FIG.

  The Hilbert transform circuit 482a is a circuit that performs a Hilbert transform on the input sine wave signal S0 and outputs an analysis signal S1b composed of a cosine wave.

  The delay circuit 482b is a circuit that performs a predetermined delay process on the input sine wave signal S0 and outputs an analysis signal S1a consisting of a sine wave. Specifically, the delay circuit 482b performs a delay process on the signal S0 for the same time as the time from when the signal S0 is input to when the analysis signal S1b is output. .

(Amplitude signal generator 483)
As shown in FIG. 5, the amplitude signal generation unit 483 performs a predetermined arithmetic process on the two analysis signals S1a and S1b to obtain a signal indicating the value of the amplitude A2 in the acoustic signal Sacin. This is a circuit for outputting an instantaneous amplitude signal S2.

Here, the two analysis signals S1a and S1b are a sine wave and a cosine wave, respectively, as described above. Therefore, the above-described amplitude A2 is obtained by using the following equation (1), which is the formula of the trigonometric function, and using the following equation (2).
^{(Sinθ) 2 + (cоsθ)} 2 = 1 ...... (1)
A2 = {(S1a) ² + (S1b) ² } ^1/2 (2)

(Counter circuit 484)
As shown in FIG. 5, the counter circuit 484 is a circuit that performs a predetermined counter process based on the instantaneous amplitude signal S2. By performing such a counter process, the generation timing of the acoustic signal Sacout from the ultrasonic transmitter 471 and the timing of the peak value (amplitude A2) of the instantaneous amplitude signal S2 will be described later in detail (see FIG. 9). And a time difference signal S3 indicating a time difference (arrival time Δt) between.

  Specifically, first, as described above, when the acoustic signal Sac of the ultrasonic wave advances in the ink 9, the speed of the acoustic signal Sac, that is, the sound speed Vs in the ink 9, increases The arrival time Δt of the acoustic signal Sac from the sound wave transmitter 471 to the ultrasonic wave receiver 472 changes. The instantaneous amplitude signal S2 indicates “0” when the acoustic signal Sac is not received, and indicates a peak value (peak value) corresponding to the amplitude A2 when the acoustic signal Sac is received. The signal becomes a bend signal (see FIG. 9 described later). Therefore, the time difference (arrival time Δt) between the timing of the peak value (amplitude A2) in the instantaneous amplitude signal S2 and the timing of generation of the acoustic signal Sacout is measured by the counter processing in the counter circuit 484, thereby making the above described. A time difference signal S3 is generated. Note that the value of the time difference signal S3 changes according to the magnitude of the sound speed Vs in the ink 9 described above.

(Acoustic signal generator 485)
As shown in FIG. 5, the acoustic signal generation unit 485 adjusts the acoustic signal period Tac of the acoustic signal Sacout transmitted from the ultrasonic transmitter 471 based on the time difference signal S3, and transmits the ultrasonic signal Sacout. Output to the device 471. Specifically, the sound signal generation unit 485 adjusts the sound wave period Tac in the sound signal Sacout so that the value of the time difference signal S3 is always kept constant even when the sound speed Vs in the ink 9 changes. It has become. The sound wave period Tac adjusted in this way is output to the waveform setting unit 487 as shown in FIG.

(Attenuation calculation unit 486)
As shown in FIG. 5, the attenuation calculating unit 486 calculates the acoustic signals Sacout (based on the amplitude A2 of the instantaneous amplitude signal S2 (corresponding to the amplitude of the acoustic signal Sacin) and the amplitude A1 of the acoustic signal Sacout. It calculates the degree of attenuation At between the transmission signal) and the acoustic signal Sacin (reception signal). Such attenuation of the amplitude between the acoustic signals Sacout and Sacin is caused by the viscous resistance of the ink 9 and the like, which will be described later in detail. The attenuation At obtained in this way is output to the waveform setting section 487 as shown in FIG.

Incidentally, such a degree of attenuation At is defined using the difference or ratio between the amplitudes A1 and A2 as shown in the following equations (3) and (4), for example.
At = (A1-A2) (3)
At = (A2 / A1) (4)

(Waveform setting unit 487)
As shown in FIG. 5, the waveform setting unit 487 determines a predetermined value in the drive signal Sd based on the sound wave period Tac output from the acoustic signal generation unit 485 and the attenuation At output from the attenuation calculation unit 486. This is for setting the waveform. Specifically, the waveform setting unit 487 calculates the pulse width Wp and the voltage value Vp of the pulse (the above-described pulses Pa, Pb, Pc, etc.) in the drive signal Sd based on the sound wave period Tac and the attenuation At. To be set. The details of the process of generating the drive signal Sd including such a waveform setting process will be described later (FIGS. 8 to 10).

[Operation and Action / Effect]
(A. Basic Operation of Printer 1)
In the printer 1, a recording operation (printing operation) of an image, a character, or the like on the recording paper P is performed as described below. In the initial state, it is assumed that the four types of ink tanks 3 (3Y, 3M, 3C, 3K) shown in FIG. 1 are each sufficiently filled with the ink 9 of the corresponding color (four colors). . Further, the ink 9 in the ink tank 3 is in a state of being filled in the ink jet head 4 via the ink supply pipe 50.

  When the printer 1 is operated in such an initial state, the grid rollers 21 in the transport mechanisms 2a and 2b rotate, respectively, so that the recording paper P is transported between the grid rollers 21 and the pinch rollers 22 in the transport direction d (X (Axial direction). At the same time as the transport operation, the drive motor 633 of the drive mechanism 63 rotates the pulleys 631a and 631b to operate the endless belt 632. Accordingly, the carriage 62 reciprocates along the width direction (Y-axis direction) of the recording paper P while being guided by the guide rails 61a and 61b. At this time, the ink jet heads 4 (4Y, 4M, 4C, 4K) appropriately discharge the four color inks 9 onto the recording paper P, thereby performing the operation of recording images, characters, and the like on the recording paper P. You.

(B. Detailed operation in the inkjet head 4)
Subsequently, a detailed operation (ejection operation of the ink 9) in the inkjet head 4 will be described. That is, in the ink jet head 4, the operation of ejecting the ink 9 using the shear (share) mode is performed as follows.

  First, the drive unit 49 applies a drive voltage Vd (drive signal Sd) to the drive electrodes (common electrode and active electrode) in the actuator plate 42 (see FIGS. 2 and 3). Specifically, the drive unit 49 applies the drive voltage Vd to each drive electrode disposed on the pair of drive walls that define the above-described ejection channel. As a result, each of the pair of driving walls is deformed so as to project toward the dummy channel adjacent to the ejection channel.

  At this time, the driving wall bends and deforms in a V-shape around an intermediate position in the depth direction of the driving wall. Then, due to such bending deformation of the drive wall, the discharge channel is deformed as if expanding. As described above, the volume of the discharge channel increases due to the bending deformation of the pair of drive walls due to the piezoelectric thickness slip effect. Then, as the volume of the ejection channel increases, the ink 9 is guided into the ejection channel.

  Next, the ink 9 guided into the ejection channel in this manner becomes a pressure wave and propagates inside the ejection channel. Then, at the timing when the pressure wave reaches the nozzle holes Hn of the nozzle plate 41 (or at a timing in the vicinity thereof), the driving voltage Vd applied to the driving electrode becomes 0 (zero) V. Thereby, as a result of the drive wall being restored from the above-mentioned bending deformation state, the volume of the discharge channel which has been once increased returns to the original state again.

  In this way, in the process of returning the volume of the ejection channel to its original state, the pressure inside the ejection channel increases, and the ink 9 in the ejection channel is pressurized. As a result, the ink 9 in the form of droplets is ejected to the outside (toward the recording paper P) through the nozzle holes Hn (see FIGS. 2 and 3). In this way, the ink 9 is ejected by the ink jet head 4 (ejection operation), and as a result, the recording operation (printing operation) of the image or the character on the recording paper P is performed.

(C. Operation of Generating Drive Signal Sd)
Next, with reference to FIGS. 7 to 10 in addition to FIGS. 1 to 6, the operation (generation processing) of generating the drive signal Sd by the signal generation unit 48 described above will be described in detail while comparing with a comparative example. I do.

(C-1. Comparative example)
FIG. 7 is a block diagram illustrating a schematic configuration example of a printer 101 as a liquid jet recording apparatus according to a comparative example. The printer 101 of the comparative example includes an inkjet head 104 as a liquid ejecting head according to the comparative example. The inkjet head 104 of this comparative example includes a driving unit 109 having a waveform information storage unit 108, in addition to the nozzle plate 41, the actuator plate 42, and the temperature detection unit 45 described above. That is, in the inkjet head 104, the acoustic measurement unit 47 and the signal generation unit 48 described above are not provided (omitted) in the inkjet head 4 (see FIG. 3) of the present embodiment, and the inkjet head 4 is replaced with the drive unit 49. In which the driving unit 109 is provided.

  The waveform information storage unit 108 in the driving unit 109 stores various types of waveform information (for example, the pulse width Wp and the voltage value Vp described above) for setting the pulses (see the pulses Pa to Pc in FIG. 4) in the driving signal Sd. Information) is stored in advance. Such waveform information is, for example, information calculated by manually observing the ejection of the ink 9 from each nozzle hole Hn in the nozzle plate 41 in advance. The drive unit 109 sets a drive signal Sd based on print data and the like input from the main body of the printer 101 using waveform information stored in advance in the waveform information storage unit 108, and sets the drive signal Sd to an actuator. The voltage is applied to the plate 42.

  By the way, in an ink jet head, it is generally known that the optimal pressure generation timing (on-pulse peak described later) and the pressure setting condition (drive voltage) greatly differ depending on the shape of the ejection channel and the physical property value of the ink 9 described above. Have been. Therefore, in this comparative example, in order to optimize the pressure generation timing and the pressure setting conditions, it is necessary to manually perform the above-described ink 9 ejection observation (flying observation) in advance. is there. However, since such waveform information using the observation of the ejection of the ink 9 is created in advance by repeating trial and error, an enormous amount of time is required, or sufficient experience and knowledge are required. In some cases, the above-described waveform information needs to be created for each type of ink 9.

  In addition, although there is a demand for a printer user (end user or the like) to freely change the ink 9, in the printer 101 of this comparative example, when the ink 9 is changed, the above-described waveform information can be appropriately used. Will be gone. That is, the pressure generation timing and the pressure setting conditions described above cannot be optimized, and there is a possibility that the print image quality may deteriorate. Therefore, in consideration of such a risk of a decrease in print image quality, it can be said that the user of the printer 101 has a very small degree of freedom in selecting the ink 9 in practice.

  As described above, in this comparative example, it is necessary to manually observe the ejection of the ink 9 from the nozzle holes Hn in advance in order to set the pulse in the drive signal Sd, which requires an enormous amount of time and labor. Therefore, it becomes as follows. That is, the convenience for the user may be impaired.

(C-2. Embodiment)
Therefore, in the inkjet head 4 of the present embodiment, the signal generation unit 48 generates the drive signal Sd as needed (automatically generates). Specifically, the signal generation unit 48 determines the pulse width Wp and the voltage value Vp of the pulses (the above-described pulses Pa, Pb, Pc, etc.) in the drive signal Sd, and has the determined pulse width Wp and voltage value Vp. The drive signal Sd is generated using a pulse. Hereinafter, the generation processing of the drive signal Sd will be described in detail.

  FIG. 8 is a flowchart illustrating a process of generating the drive signal Sd according to the present embodiment. Note that among the series of processes (steps S10 to S17 to be described later) illustrated in FIG. 8, the processes of steps S11 to S16 to be described later correspond to the generation process of the drive signal Sd.

  FIG. 9 is a timing chart showing waveform examples of various signals in the process of generating the drive signal Sd shown in FIG. Specifically, in FIG. 9, (A) shows the measurement start signal Sm indicating the measurement start timing in the sound measurement unit 47, (B) and (C) show the above-described sound signals Sacout and Sacin, respectively, D) and (E) show the instantaneous amplitude signal S2 and the time difference signal S3, respectively. In FIG. 9, the horizontal axis indicates time t.

  In the series of processes illustrated in FIG. 8, first, as a previous step, the signal generation unit 48 determines whether it is necessary to generate (update) the drive signal Sd (step S10). Here, when it is determined that the generation of the drive signal Sd is necessary (Step S10: Y), the process proceeds to the drive signal Sd generation processing (Steps S11 to S16) described below. On the other hand, when it is determined that the generation of the drive signal Sd is not necessary (Step S10: N), the process proceeds to Step S17 described later, and the ejection operation of the ink 9 is performed based on the drive signal Sd at the current stage. Will be.

  The case where the drive signal Sd needs to be generated includes, for example, the following cases. That is, for example, when a predetermined time has elapsed, when the cartridge of the ink tank 3 is mounted, when a predetermined operation signal is input from the user to the printer 1, a non-ejection period (idle period) of the ink 9 is set. For example, when the predetermined time is exceeded.

  Next, in the generation processing of the drive signal Sd (steps S11 to S16), the signal generation unit 48 calculates the pulse width Wp of the pulse (steps S11 to S13) and calculates the voltage value Vp of the pulse (steps S14 to S13). S15) is performed in parallel (see FIG. 8).

(Steps S11 to S13: Pulse width Wp calculation processing)
Here, in the calculation processing of the pulse width Wp, first, the signal generation unit 48 obtains the arrival time Δt of the acoustic signal Sac in the ink 9 (step S11). That is, as shown in FIG. 9, for example, the signal generation unit 48 starts from the rising timing (timing t1) of the measurement start signal Sm to the timing (timing t2) indicating the peak value (amplitude A2) in the instantaneous amplitude signal S2. An arrival time Δt corresponding to the time difference is obtained. Specifically, the counter circuit 484 in the signal generator 48 calculates such an arrival time Δt by the above-described method (see FIG. 5).

  Next, the signal generation unit 48 obtains the sound speed Vs in the ink 9 based on the arrival time Δt thus obtained (step S12). More specifically, the sound signal period Tac (see FIG. 9B) is obtained by the above-described method in the sound signal generation unit 485 of the signal generation unit 48, so that the sound wave period Tac and the ultrasonic wave transmitter 471 are obtained. The sound velocity Vs in the ink 9 is obtained based on the physical distance from the ultrasonic receiver 472 to the ultrasonic receiver 472.

  Subsequently, the signal generation unit 48 obtains a pulse width Wp of the pulse based on the sound speed Vs in the ink 9 thus obtained (step S13). Specifically, the waveform setting section 487 in the signal generation section 48 sets the pulse width Wp based on the sound speed Vs (see FIG. 5).

  Here, a method of setting the pulse width Wp and the like will be described with reference to FIG. FIG. 10 schematically shows an outline of a setting method of the pulse width Wp and the like.

First, when it is considered that the ejection speed (ejection speed) of the ink 9 is maximized, for example, as shown in FIG. 10, the pulse length of the drive signal Sd corresponds to the channel length L of the ejection channel Ce described above. Is defined as the following equation (5). Then, by using the equation (5), the pulse width Wp (on-pulse peak (AP): see FIG. 10) for maximizing the ejection speed of the ink 9 can be obtained.
(2 × Wp) = (2 × L) / (N × Vs) (N = 1, 2, 3,...) (5)

  Incidentally, this AP corresponds to a period (1AP = (natural vibration period of ink 9) / 2) of the natural vibration period of ink 9 in ejection channel Ce. Then, when the pulse width Wp is set to this AP, as described above, the ejection speed (ejection efficiency) of the ink 9 is maximized when ejecting the ink 9 for one ordinary droplet (ejection of one droplet). Become. The AP is defined, for example, by the shape of the ejection channel Ce and the physical property value (specific gravity and the like) of the ink 9.

(Steps S14 to S15: Voltage Value Vp Calculation Processing)
On the other hand, in the calculation process of the voltage value Vp, first, the signal generation unit 48 obtains the degree of attenuation At of the acoustic signal Sac in the ink 9 (step S14). Specifically, the attenuation calculating unit 486 in the signal generating unit 48 calculates the difference between the amplitude A2 of the instantaneous amplitude signal S2 (corresponding to the amplitude of the acoustic signal Sacin) and the amplitude A1 of the acoustic signal Sacout by the above-described method. (See FIG. 9).

  Next, the signal generation unit 48 obtains the voltage value Vp of the pulse based on the attenuation At obtained in this manner (step S15). Specifically, the waveform setting section 487 in the signal generation section 48 sets the voltage value Vp based on the attenuation At (see FIG. 5). At this time, the signal generator 48 may control the voltage value Vp (voltage control) in consideration of the actuator temperature Tpzt detected by the temperature detector 45.

  Here, the attenuation of the amplitude between the acoustic signals Sacout and Sacin is caused by the viscous resistance of the ink 9 as described above, and when the acoustic signal Sac passes through the ink 9. Represents the amount of energy loss. In general, examples of such energy loss of ultrasonic waves include scattering attenuation caused by non-uniformity of a medium due to bubbles in a liquid and absorption attenuation caused by viscous resistance. In general, the ink used in the printer is often degassed, and thus the main factor of energy loss in this case is viscous resistance.

  Further, for example, when the ejection speed of the ink falls within a predetermined range, there is a very strong correlation between the temperature dependence of the viscosity of the ink and the temperature dependence of the driving voltage required at that time. It has been known. This also indicates that the viscous resistance of the ink has a strong relationship with the loss of ultrasonic energy.

  From these facts, it can be said that an appropriate drive voltage (pulse voltage value Vp) can be obtained based on the attenuation At that represents the energy loss of the ultrasonic wave.

  When setting the voltage value Vp based on the attenuation At, for example, the physical characteristics of the means for obtaining acoustic energy for discharging the ink 9 and the electromechanical characteristic values of the actuator plate 42 (piezoelectric body) Such information is required. Therefore, when setting the voltage value Vp based on the degree of attenuation At, a predetermined correction function, a lookup table for correction, or the like may be used. Alternatively, information defining the relationship between the attenuation degree At and the voltage value Vp may be stored in the signal generator 48 in advance, and the rate of change of the voltage value Vp may be determined from the rate of change of the attenuation degree At. .

(Steps S16 and S17: Generation of Drive Signal Sd, Operation of Injecting Ink 9)
Subsequently, the signal generation unit 48 generates the drive signal Sd as shown in FIG. 4 described above, for example, using the pulse having the pulse width Wp and the voltage value Vp obtained in this manner (step S16). ). Then, the signal generation unit 48 applies such a drive signal Sd to the actuator plate 42 to eject the ink 9 from the nozzle holes Hn (Step S17). In this way, the above-described ejection operation of the ink 9 is performed.

  This is the end of the series of processes illustrated in FIG.

(C-3. Action / Effect)
Thus, in the ink jet head 4 of the present embodiment, the transmitter (ultrasonic transmitter 471) and the receiver (ultrasonic receiver 472) of the ultrasonic acoustic signal Sac in the ink 9 in the acoustic measuring unit 47 are provided. The pulse of the drive signal Sd is set based on the comparison of the signals in ()). Then, the drive signal Sd is generated using the set pulse, and the generated drive signal Sd is applied to the actuator plate 42, so that the ink 9 is ejected from the nozzle holes Hn in the nozzle plate 41. . That is, the ejection operation of the ink 9 is performed using the drive signal Sd automatically generated in the inkjet head 4 using the ultrasonic acoustic signal Sac.

  Thus, in the present embodiment, unlike the above-described comparative example and the like, the following is achieved. That is, it is not necessary to manually observe the ejection of the ink 9 from the nozzle holes Hn in advance for setting the pulse in the drive signal Sd. Therefore, a pulse (drive signal Sd) suitable for the drive condition at each time can be automatically generated in the inkjet head 4 at any time without requiring an enormous amount of time and labor.

  As described above, in the present embodiment, it is possible to improve the convenience for the user (end user or the like) as compared with the above-described comparative example and the like. Further, for example, it is also possible to significantly reduce investment in measurement equipment and fixed costs, which are separately required when observing the ejection of the ink 9 described above. Further, the degree of freedom in selecting the ink 9 can be greatly improved, and the degree of freedom in using the printer 1 by the user can also be improved.

  Further, in the present embodiment, the sound speed Vs in the ink 9 is obtained based on the arrival time Δt in the ultrasonic acoustic signal Sac, and the pulse width Wp of the pulse is determined based on the sound speed Vs in the ink 9. It is as follows because it is required. That is, a pulse more appropriately set for the driving condition is generated, so that the ejection stability of the ink 9 can be improved.

  Further, in the present embodiment, the degree of attenuation At in the acoustic signal Sac of the ultrasonic wave is obtained, the voltage value Vp of the pulse is obtained based on the degree of attenuation At, and the obtained voltage value Vp and the pulse width Wp are obtained. The drive signal Sd is generated using the pulse. That is, a pulse having a pulse width Wp obtained based on the sound speed Vs in the ink 9 and a voltage value Vp obtained based on the attenuation At is automatically generated in the inkjet head 4. In this manner, in addition to the above-described pulse width Wp, the voltage value Vp that contributes to the ejection characteristics of the ink 9 is also automatically adjusted. It will be automatically generated. Therefore, the convenience for the user can be further improved.

<2. Modification>
Next, modified examples (modified examples 1 and 2) of the above embodiment will be described. It is to be noted that the same components as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

[Modification 1]
FIG. 11 is a block diagram illustrating a schematic configuration example of a printer 1a as a liquid jet recording apparatus according to the first modification. The printer 1a of the first modification corresponds to the printer 1 of the embodiment in which an inkjet head 4a described below is provided instead of the inkjet head 4.

  Note that the printer 1a corresponds to a specific example of “liquid jet recording apparatus” in the present disclosure. Further, the inkjet head 4a corresponds to a specific example of “liquid jet head” in the present disclosure.

  In the ink jet head 4a of the first modification, as shown in FIG. 11, the arrangement position of the sound measuring unit 47 is changed in the ink jet head 4 of the embodiment (see FIG. 3), and a part of the sound measuring unit 47 is It is provided inside the actuator plate 42. Specifically, in the example of FIG. 11, the ultrasonic transmitter 471 and the ultrasonic receiver 472 in the acoustic measurement unit 47 are respectively arranged in the actuator plate 42. Incidentally, other parts (for example, a predetermined amplifier, a digital-to-analog conversion circuit (DAC: Digital to Analog Converter), an analog-digital conversion circuit (ADC: Analog to Digital Converter), etc.) in the sound measurement unit 47 are actuators. It is arranged outside the plate 42.

  In the first modification of such a configuration, basically, the same effect can be obtained by the same operation as that of the embodiment.

  In particular, in the first modification, since a part of the acoustic measurement unit 47 is provided in the actuator plate 42, the acoustic signal Sac of the ultrasonic wave The transmission and the reception are performed respectively. As a result, the drive signal Sd suitable for the ink 9 is easily generated as compared with the ink jet head 4 of the embodiment, so that the convenience for the user can be further improved.

  In the first modification, the case where a part of the acoustic measurement unit 47 is provided in the actuator plate 42 has been described as an example. It may be made to be provided inside. Further, for example, a part or the whole of the acoustic measurement unit 47 may be arranged inside both the actuator plate 42 and the nozzle plate 41.

[Modification 2]
FIG. 12 is a block diagram illustrating a schematic configuration example of a printer 1b as a liquid jet recording apparatus according to Modification Example 2. The printer 1b of the second modification corresponds to the printer 1 of the embodiment in which an inkjet head 4b described below is provided instead of the inkjet head 4.

  Note that the printer 1b corresponds to a specific example of “liquid jet recording apparatus” in the present disclosure.

  As shown in FIG. 12, the inkjet head 4b according to the second modification is different from the inkjet head 4 according to the embodiment (see FIG. 3) in that the acoustic measurement unit 47 and the signal generation unit 48 are respectively provided outside the inkjet head 4b. It corresponds to what is provided. That is, both the acoustic measurement unit 47 and the signal generation unit 48 are arranged outside the inkjet head 4b in the printer 1b. Therefore, only the nozzle plate 41, the actuator plate 42, the temperature detecting unit 45, and the driving unit 49 are provided in the inkjet head 4b of the second modification (see FIG. 12).

  Also in the modified example 2 having such a configuration, since the printer 1b as a whole has the same configuration as the printer 1 or the printer 1a described above, the same operation as the embodiment or the modified example 1 is performed. The same effect can be obtained.

  In particular, in the second modification, the acoustic measurement unit 47 and the signal generation unit 48 are provided outside the ink jet head 4b, respectively, so that, for example, the following effects can be obtained. That is, for example, even when the inkjet head 4b having an existing configuration is used, the acoustic signal measuring unit 47, the signal generating unit 48, and the like are arranged in the printer 1b to generate the driving signal Sd as described above. Processing and the like can be realized.

<3. Other Modifications>
As described above, the present disclosure has been described with reference to the embodiments and the modifications, but the present disclosure is not limited to these embodiments and the like, and various modifications are possible.

  For example, in the above-described embodiment and the like, the configuration examples (shape, arrangement, number, and the like) of each member in the printer and the ink-jet head have been specifically described, but are not limited to those described in the above-described embodiment and the like. , Other shapes, arrangements, numbers, and the like. Specifically, for example, the measurement is performed by the ultrasonic transmitter 471 and the ultrasonic receiver 472 using the nozzle hole Hn on the nozzle plate 41 or the dummy nozzle hole separately provided on the nozzle plate 41. It may be. Further, in the above-described embodiments and the like, the shuttle type printer in which the inkjet head moves is described as an example. However, the invention is not limited to this example. For example, a single-pass type printer to which the inkjet head is fixed may be used. Is also good. Further, in the above-described embodiments and the like, the case where the ink tank is housed in a predetermined housing has been described as an example. However, the present invention is not limited to this example, and the ink tank is arranged outside the housing. It may be. In addition, one of the acoustic measurement unit 47 and the signal generation unit 48 may be arranged inside the printer (outside the inkjet head), and the other may be arranged inside the inkjet head.

  Further, as the structure of the inkjet head, each type can be applied. That is, for example, a so-called side chute type ink jet head that discharges the ink 9 from the center of the actuator plate in the extending direction of each discharge channel may be used. Alternatively, for example, a so-called edge shoot type ink jet head that discharges the ink 9 along the extending direction of each discharge channel may be used. Further, the method of the printer is not limited to the method described in the above embodiment, and various methods such as a thermal method (thermal type on demand type) and a MEMS (Micro Electro Mechanical Systems) method are applied. It is possible to

  Further, in the above-described embodiments and the like, a description has been given of an example of the non-circulation type ink jet head which uses the ink 9 without circulating between the ink tank and the ink jet head, but is not limited to this example. . That is, for example, the present disclosure can be applied to a circulating inkjet head that circulates and uses the ink 9 between the ink tank and the inkjet head.

  In addition, in the above-described embodiment and the like, the example of the processing of generating the drive signal Sd by the signal generation unit 48 is specifically described. However, the present invention is not limited to the example of the above-described embodiment and the like. The generation processing of the drive signal Sd may be performed by using a technique. Specifically, for example, in the above-described embodiment and the like, the case where the drive signal Sd is generated after setting (automatically adjusting) both the pulse width Wp and the voltage value (peak value) Vp of the pulse will be described as an example. Although described, the present invention is not limited to this example. That is, for example, the drive signal Sd may be generated after setting only one of the pulse width Wp and the voltage value Vp among the pulse width Wp and the voltage value Vp of the pulse. Further, in the above-described embodiment and the like, a sine wave is used as the acoustic signal Sac. However, the present invention is not limited to this example. For example, the acoustic signal Sac may be configured using a pulse-like waveform. In this case, it is possible to perform measurement in the acoustic measurement unit 47 using the actual waveform shape used for discharging the ink 9.

  Further, in the above-described embodiment and the like, the case where the pulse (pulse Pa, Pb, Pc) for expanding the volume in each ejection channel is a pulse (positive pulse) for expanding in the period of the High state is described. However, this is not a limitation. That is, not only a pulse that expands during the high state and contracts during the low state, but also a pulse that expands during the low state and contracts during the high state (negative pulse). It may be.

  Further, for example, a pulse for assisting the ejection of the droplet may be additionally applied during the OFF period immediately after the ON period. Examples of the pulse for assisting the ejection of the droplet include a pulse for contracting the volume in each ejection channel and a pulse (auxiliary pulse) for pulling back a part of the ejected droplet. . The pulse (main pulse) applied immediately before the latter auxiliary pulse has, for example, a pulse width equal to or less than the width of the on-pulse peak (AP). Note that the addition of such a pulse for assisting the ejection of the droplet does not affect the contents of the present disclosure (driving method and the like) described above.

  Further, a series of processes described in the above embodiments and the like may be performed by hardware (circuit) or may be performed by software (program). When performed by software, the software includes a group of programs for causing a computer to execute each function. Each program may be used by being incorporated in the computer in advance, for example, or may be used by being installed in the computer from a network or a recording medium.

  Furthermore, in the above-described embodiment and the like, the printer 1 (inkjet printer) has been described as a specific example of the “liquid jet recording apparatus” in the present disclosure. The present disclosure can be applied to an apparatus. In other words, the “liquid jet head” (ink jet head) of the present disclosure may be applied to another device other than the ink jet printer. Specifically, for example, the “liquid ejecting head” of the present disclosure may be applied to an apparatus such as a facsimile or an on-demand printing machine.

  In addition, the various examples described above may be applied in any combination.

  It should be noted that the effects described in this specification are merely examples and are not limited, and may have other effects.

In addition, the present disclosure may have the following configurations.
(1)
An ejection unit having a plurality of nozzles for ejecting a liquid,
A drive unit that ejects the liquid from the nozzle by applying a drive signal having one or more pulses to the ejection unit,
A transmitter that transmits an ultrasonic acoustic signal into the liquid, and a receiver that receives the ultrasonic acoustic signal from the liquid,
A signal generation unit that generates the drive signal,
The signal generator,
Based on the comparison of the signal in the transmitter and the receiver in the acoustic measurement unit, set the pulse,
A liquid ejecting head that generates the drive signal using the set pulse.
(2)
The signal generator,
Based on the arrival time in the liquid from the transmitter to the receiver in the acoustic signal of the ultrasonic wave, to determine the sound speed in the liquid,
Based on the determined sound velocity in the liquid, determine the pulse width of the pulse,
The liquid ejection head according to (1), wherein the drive signal is generated using the pulse having the determined pulse width.
(3)
The signal generator,
Determine the degree of attenuation in the liquid from the transmitter to the receiver in the ultrasonic acoustic signal,
Based on the obtained degree of attenuation, further obtain a peak value in the pulse,
The liquid ejection head according to (2), wherein the drive signal is generated using the pulse having the obtained peak value and the pulse width.
(4)
The liquid ejection head according to any one of (1) to (3), wherein at least a part of the acoustic measurement unit is provided in the ejection unit.
(5)
A liquid jet recording apparatus comprising the liquid jet head according to any one of the above (1) to (4).
(6)
A system for generating a drive signal having one or a plurality of pulses applied to an ejection unit having a plurality of nozzles for ejecting a liquid,
A transmitter that transmits an ultrasonic acoustic signal into the liquid, and a receiver that receives the ultrasonic acoustic signal from the liquid,
A signal generation unit that generates the drive signal,
The signal generator,
Based on the comparison of the signal in the transmitter and the receiver in the acoustic measurement unit, set the pulse,
A drive signal generation system that generates the drive signal using the set pulse.

  1, 1a, 1b printer, 10 housing, 2a, 2b transport mechanism, 21 grid roller, 22 pinch roller, 3 (3Y, 3M, 3C, 3K) ink tank, 4 (4Y, 4M, 4C) , 4K), 4a, 4b: inkjet head, 41: nozzle plate, 42: actuator plate, 45: temperature detector, 47: acoustic measuring unit, 471: ultrasonic transmitter, 472: ultrasonic receiver, 48: signal Generator 481 bandpass filter 482 analytic signal generator 482a Hilbert transform circuit 482b delay circuit 483 amplitude signal generator 484 counter circuit 485 acoustic signal generator 486 attenuation Arithmetic operation unit, 487: waveform setting unit, 49: drive unit, 50: ink supply tube, 6: scanning mechanism, 61a, 61b: guide rail, 62: carriage , 63 drive mechanism, 631a, 631b pulley, 632 endless belt, 633 drive motor, 9 ink, P recording paper, d transport direction, Hn nozzle hole, Ce discharge channel, Sd drive signal , Vd: drive voltage, Tpzt: actuator temperature, Wp: pulse width, Vp: voltage value (peak value), Vs: sound speed, Pa, Pb, Pc: pulse, Sac, Sacin, Sacout: sound signal, S0: signal, S1a, S1b: analysis signal, S2: instantaneous amplitude signal, S3: time difference signal, Sm: measurement start signal, A1, A2: amplitude, At: attenuation, L: channel length, t: time, t1, t2: timing, Δt: arrival time, Tac: sound wave period.

Claims (6)

An ejection unit having a plurality of nozzles for ejecting a liquid,
A drive unit that ejects the liquid from the nozzle by applying a drive signal having one or more pulses to the ejection unit,
A transmitter that transmits an ultrasonic acoustic signal into the liquid, and a receiver that receives the ultrasonic acoustic signal from the liquid,
A signal generation unit that generates the drive signal,
The signal generator,
Based on the comparison of the signal in the transmitter and the receiver in the acoustic measurement unit, set the pulse,
A liquid ejecting head that generates the drive signal using the set pulse. The signal generator,
Based on the arrival time in the liquid from the transmitter to the receiver in the acoustic signal of the ultrasonic wave, to determine the sound speed in the liquid,
Based on the determined sound velocity in the liquid, determine the pulse width of the pulse,
The liquid ejecting head according to claim 1, wherein the drive signal is generated using the pulse having the determined pulse width. The signal generator,
Determine the degree of attenuation in the liquid from the transmitter to the receiver in the ultrasonic acoustic signal,
Based on the obtained degree of attenuation, further obtain a peak value in the pulse,
The liquid ejecting head according to claim 2, wherein the drive signal is generated using the pulse having the obtained peak value and the pulse width. The liquid ejecting head according to any one of claims 1 to 3, wherein at least a part of the acoustic measuring unit is provided in the ejecting unit. A liquid jet recording apparatus comprising the liquid jet head according to claim 1. A system for generating a drive signal having one or a plurality of pulses applied to an ejection unit having a plurality of nozzles for ejecting a liquid,
A transmitter that transmits an ultrasonic acoustic signal into the liquid, and a receiver that receives the ultrasonic acoustic signal from the liquid,
A signal generation unit that generates the drive signal,
The signal generator,
Based on the comparison of the signal in the transmitter and the receiver in the acoustic measurement unit, set the pulse,
A drive signal generation system that generates the drive signal using the set pulse.

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