JP7077192B2 - Liquid injection head, liquid injection recording device and drive signal generation system - Google Patents

Description

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

A liquid injection recording device provided with a liquid injection head is used in various fields, and various types of liquid injection heads have been developed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2-253960

Such a liquid injection head is required to improve convenience for the user. It is desirable to provide a liquid injection head, a liquid injection recording device and a drive signal generation system capable of improving convenience for the user.

The liquid injection head according to the embodiment of the present disclosure is a nozzle by applying a jet unit having a plurality of nozzles for injecting a liquid and a drive signal having one or a plurality of drive waveforms to the injection unit. It is provided with a drive unit that injects a liquid from the surface, an arithmetic processing unit that performs predetermined arithmetic processing, and a signal generation unit that generates the drive signal using a reference drive waveform that serves as a reference for the drive waveform. .. The arithmetic processing unit sets a sampling frequency when generating the drive signal based on the arithmetic processing. The signal generation unit sets the pulse width in the drive waveform by changing the pulse width in the reference drive waveform according to the sampling frequency set in the arithmetic processing unit, and sets the set pulse width. The drive signal is generated using the drive waveform.

The liquid injection recording device according to the embodiment of the present disclosure includes the liquid injection head according to the embodiment of the present disclosure.

The drive signal generation system according to the embodiment of the present disclosure is a system that generates a drive signal having one or more drive waveforms applied to an injection unit having a plurality of nozzles for injecting a liquid. It is provided with an arithmetic processing unit that performs predetermined arithmetic processing and a signal generation unit that generates the driving signal by using a reference driving waveform that is a reference of the driving waveform. The arithmetic processing unit sets a sampling frequency when generating the drive signal based on the arithmetic processing. The signal generation unit sets the pulse width in the drive waveform by changing the pulse width in the reference drive waveform according to the sampling frequency set in the arithmetic processing unit, and sets the set pulse width. The drive signal is generated using the drive waveform.

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

It is a schematic perspective view which shows the schematic structural example of the liquid injection recording apparatus which concerns on one Embodiment of this disclosure. It is a schematic diagram which shows the schematic structural example of the liquid injection head and the circulation mechanism shown in FIG. FIG. 3 is a block diagram showing a detailed configuration example of the liquid injection head and the circulation mechanism shown in FIG. 2. It is a schematic diagram which shows the detailed configuration example of the sound velocity measuring part shown in FIG. It is a figure which shows the structural example of the table shown in FIG. It is a block diagram which shows the detailed configuration example of the PLL circuit shown in FIG. It is a timing diagram which shows the structural example of a drive signal schematically. It is a block diagram which shows the schematic structure example of the liquid injection recording apparatus which concerns on a comparative example. It is a timing diagram which shows the adjustment method of the pulse width which concerns on a comparative example. It is a flow chart which shows an example of the table generation processing which concerns on embodiment. It is a flow chart which shows an example of the generation process of the drive signal which concerns on embodiment. It is a schematic diagram for demonstrating the resonance in a discharge channel. It is a schematic diagram for demonstrating the outline of the pulse width adjustment method which concerns on embodiment. It is a timing diagram which shows an example of the adjustment method of the pulse width which concerns on embodiment. It is a block diagram which shows the schematic structure example of the liquid injection recording apparatus which concerns on modification 1. It is a block diagram which shows the schematic structure example of the liquid injection recording apparatus which concerns on modification 2.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The explanation will be given in the following order.
1. 1. Embodiment (Example in the case where the temperature control mechanism and the sound velocity measuring unit are provided inside the liquid injection head)
2. 2. Deformation example Deformation example 1 (Example when the temperature control mechanism and sound velocity measuring unit are provided outside the liquid injection head)
Modification 2 (Example when the arithmetic processing unit, signal generation unit, etc. are also provided outside the liquid injection head)
3. 3. Other variants

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

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, a circulation mechanism 5, and a scanning mechanism 6. Each of these members is housed in a housing 10 having a predetermined shape. In each drawing used in the description of the present specification, the scale of each member is appropriately changed in order to make each member recognizable.

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

As shown in FIG. 1, the transport mechanisms 2a and 2b are mechanisms for transporting the recording paper P along the transport direction d (X-axis direction), respectively. These transport mechanisms 2a and 2b each have 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 an axis (rotates in the ZX plane), and is configured by, for example, a motor or the like.

(Ink tank 3)
The ink tank 3 is a tank that houses the ink 9 inside. As the ink tank 3, as shown in FIG. 1 in this example, four inks 9 of four colors of yellow (Y), magenta (M), cyan (C), and black (K) are individually stored. There are different types of tanks. That is, the ink tank 3Y containing the yellow ink 9, the ink tank 3M containing the magenta ink 9, the ink tank 3C containing the cyan ink 9, and the ink tank 3K containing the black ink 9 are It is provided. These ink tanks 3Y, 3M, 3C, and 3K are arranged side by side in the housing 10 along the X-axis direction.

Since the ink tanks 3Y, 3M, 3C, and 3K each have the same configuration except for the color of the ink 9 to be accommodated, they will be collectively referred to as the ink tank 3 below.

(Inkjet head 4)
The inkjet head 4 is a head that ejects (discharges) droplet-shaped ink 9 onto the recording paper P from a plurality of nozzles (nozzle holes Hn) described later to record (print) images, characters, and the like. .. As the inkjet head 4, as shown in FIG. 1 in this example, four types of heads individually eject the four color inks 9 contained in the ink tanks 3Y, 3M, 3C, and 3K described above. Is provided. That is, the inkjet head 4Y that ejects the yellow ink 9, the inkjet head 4M that ejects the magenta ink 9, the inkjet head 4C that ejects the cyan ink 9, and the inkjet head 4K that ejects the black ink 9. It is provided. These inkjet heads 4Y, 4M, 4C, and 4K are arranged side by side in the housing 10 along the Y-axis direction.

Since the inkjet heads 4Y, 4M, 4C, and 4K each have the same configuration except for the color of the ink 9 to be used, they will be collectively referred to as the inkjet head 4 below. A detailed configuration example of the inkjet head 4 will be described later (FIGS. 2 to 6).

The circulation mechanism 5 is a mechanism for circulating the ink 9 between the inside of the ink tank 3 and the inside of the inkjet head 4. The circulation mechanism 5 includes a flow path (circulation flow path 50) for circulating the ink 9. A detailed configuration example of the circulation mechanism 5 will be described later (FIG. 2).

(Scanning mechanism 6)
The scanning mechanism 6 is a mechanism for scanning the inkjet head 4 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 these guide rails 61a and 61b. , 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 arranged between the guide rails 61a and 61b, an endless belt 632 wound between these pulleys 631a and 631b, and a drive motor 633 for rotationally driving the pulleys 631a. And have. Further, on the carriage 62, the above-mentioned four types of inkjet heads 4Y, 4M, 4C, and 4K are arranged side by side along the Y-axis direction.

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

[B. Detailed configuration of the inkjet head 4 and the circulation mechanism 5]
Subsequently, a detailed configuration example of the inkjet head 4 and the circulation mechanism 5 will be described with reference to FIGS. 2 to 6.

Here, FIG. 2 schematically shows a schematic configuration example of the inkjet head 4 and the circulation mechanism 5. Further, FIG. 3 is a block diagram showing a detailed configuration example of the inkjet head 4 and the circulation mechanism 5 shown in FIG.

(B-1. Circulation mechanism 5)
As shown in FIGS. 1 to 3, the circulation mechanism 5 includes a circulation flow path 50 composed of an ink supply pipe 50a and an ink discharge pipe 50b, a pressurizing pump 52a provided in the ink supply pipe 50a, and ink. It is provided with a suction pump 52b provided in the discharge pipe 50b. Each of the ink supply pipe 50a and the ink discharge pipe 50b is composed of, for example, a flexible hose having flexibility enough to follow the operation of the scanning mechanism 6 described above.

The pressurizing pump 52a pressurizes the inside of the ink supply pipe 50a and sends out the ink 9 to the inkjet head 4 through the ink supply pipe 50a. On the other hand, the suction pump 52b decompresses the inside of the ink discharge pipe 50b and sucks the ink 9 from the inkjet head 4 through the ink discharge pipe 50b. The ink 9 can be circulated between the inkjet head 4 and the ink tank 3 through the circulation flow path 50 by driving the pressurizing pump 52a and the suction pump 52b (broken line in FIGS. 2 and 3). See the arrow).

(B-2. Inkjet head 4)
As shown in FIGS. 2 and 3, the inkjet head 4 includes a nozzle plate 41, an actuator plate 42, a temperature control mechanism 43, a sound velocity measurement unit 44, a temperature detection unit 45, an arithmetic processing unit 46, and a PLL (Phase Locked Loop). It has a circuit 47, a fixed frequency oscillator 40, a signal generation unit 48, and a drive unit 49.

The nozzle plate 41 and the actuator plate 42 correspond to a specific example of the "injection unit" in the present disclosure. Further, the arithmetic processing unit 46 and the signal generation unit 48 correspond to a specific example of the "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 ink 9 as shown in FIGS. 2 and 3 (FIG. 2). , See the dashed arrow in Figure 3). Each of these nozzle holes Hn is formed side by side in a straight line (in this example, along the X-axis direction) at predetermined intervals. Each nozzle hole Hn corresponds to a specific example of the "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 is provided with 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 so as to be parallel to each other at predetermined intervals. Each channel is defined by a drive wall (not shown) made of a piezoelectric material, and is a concave groove in a cross-sectional view.

In such a channel, there are a ejection channel for ejecting the ink 9 (ejection channel Ce described later: see FIG. 12) and a dummy channel (non-ejection channel) for not ejecting 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. Further, 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 discharge channels and dummy channels are arranged alternately side by side along a predetermined direction.

Drive electrodes (not shown) are provided on the opposite inner side surfaces of the above-mentioned drive wall. The drive electrode includes a common electrode (common electrode) provided on the inner surface facing the discharge channel and an active electrode (individual electrode) provided on the inner surface facing the dummy channel. These drive electrodes and the drive circuit in the drive substrate (not shown) are electrically connected via a plurality of drawer electrodes formed on the flexible substrate (not shown). As a result, the drive voltage Vd (drive signal Sd) described later is applied to each drive electrode from the drive circuit including the drive unit 49 described later via this flexible substrate.

(Temperature control mechanism 43)
As shown in FIG. 3, the temperature control mechanism 43 is a mechanism for adjusting the temperature (temperature Ti, which will be described later) of the ink 9 flowing in the ink supply tube 50a described above. Such a temperature control mechanism 43 is configured by using, for example, a temperature raising mechanism (heater), a temperature lowering mechanism (cooler), or the like, and operation control is performed by an arithmetic processing unit 46 described later.

(Sound velocity measuring unit 44)
As shown in FIG. 3, the sound velocity measuring unit 44 performs predetermined measurement (acoustic measurement, measurement of sound velocity Vs in the ink 9) with respect to the ink 9 flowing in the ink supply tube 50a described above. The operation control for the sound velocity measuring unit 44, the input / output of various data, and the like are performed by the arithmetic processing unit 46, which will be described later.

FIG. 4 schematically shows a detailed configuration example of such a sound velocity measuring unit 44. Specifically, FIG. 4A schematically shows a detailed configuration example of the sound velocity measuring unit 44. Further, FIGS. 4 (B) and 4 (C) show examples of waveforms in the acoustic signal Sac (Sacout) and the acoustic signal Sac (Sacin) described below in a timing diagram, respectively. The horizontal axis in FIGS. 4 (B) and 4 (C) indicates time t.

As shown in FIG. 4A, the sound velocity measuring unit 44 includes the flow path 440 of the ink 9 connected to the ink supply tube 50a, the sound wave transmitter 441a, the sound wave receiver 441b, and the inside of the flow path 440. It has a temperature detection unit 442 and a temperature detection unit 442 for detecting the temperature of the ink 9 (temperature Ti described later).

The sound wave transmitter 441a is a device that transmits an acoustic signal Sac of a sound wave (ultrasonic wave) as an acoustic signal Sacout toward the ink 9 flowing in the flow path 440. It should be noted that such an acoustic signal Sacout is transmitted by using an electric-mechanical conversion based on, for example, an electric signal output from the arithmetic processing unit 46 described later (see FIG. 3).

The sound wave receiver 441b is a device that receives an acoustic signal Sac of a sound wave (ultrasonic wave) from the ink 9 flowing in the flow path 440. Specifically, the sound wave receiver 441b receives the acoustic signal Sac output from the sound wave transmitter 441a and traveling through the ink 9 as the acoustic signal Sacin. It should be noted that such reception of the acoustic signal Sacin is performed by using, for example, a machine-electrical conversion, and the acoustic signal Sacin thus obtained is output to the arithmetic processing unit 46 described later. (See Fig. 3).

Incidentally, each of such acoustic signals Sac (Sacout, Sacin) is configured by using a sine wave in the present embodiment (see FIGS. 4 (B) and 4 (C)). Further, as the ink 9 progresses, the amplitude of the acoustic signal Sacin is attenuated with respect to the amplitude of the acoustic signal Sacout.

Further, as shown in FIG. 4, the physical distance Δd from the sound wave transmitter 441a to the sound wave receiver 441b and the acoustic signal Sac in the ink 9 from the sound wave transmitter 441a to the sound wave receiver 441b. Using the propagation time Δt, the sound wave Vs in the ink 9 is defined as the following equation (1).
Vs = (Δd / Δt) …… (1)

(Temperature detection unit 45)
As shown in FIG. 3, the temperature detection unit 45 detects the temperature (actuator temperature Tpzt) in the vicinity of the actuator plate 42 in the inkjet head 4. The actuator temperature Tpzt detected by the temperature detection unit 45 in this way is output to the arithmetic processing unit 46, which will be described later.

(Arithmetic processing unit 46)
The arithmetic processing unit 46 sets a frequency division ratio (multiplier) N when generating a drive signal Sd applied to the actuator plate 42 from the drive unit 49 described later based on a predetermined arithmetic process described later. (N: integer). Specifically, the arithmetic processing unit 46 determines the division ratio N when generating the sampling frequency fsamp based on the sound velocity Vs in the ink 9, which will be described in detail later, as such arithmetic processing. It is designed to be set. Further, the arithmetic processing unit 46 uses the table TB that defines a predetermined correspondence relationship to obtain the sound velocity Vs in the ink 9.

FIG. 5 shows a configuration example of such a table TB. As shown in FIG. 5, in the table TB, the correspondence between the temperature Ti of the ink 9 and the speed of sound Vs in the ink 9 is defined. Such a table TB is generated by using the temperature control mechanism 43 and the sound velocity measuring unit 44 described above. Specifically, although the details will be described later (FIG. 10), the sound velocity Vs in the ink 9 is measured by using the sound velocity measuring unit 44 while adjusting the temperature Ti of the ink 9 by using the temperature adjusting mechanism 43. As a result, the table TB is generated.

(PLL circuit 47)
As shown in FIG. 3, the PLL circuit 47 has a drive signal Sd in the signal generation unit 48, which will be described later, based on the frequency division ratio N set in the arithmetic processing unit 46 and the reference frequency f0 (reference clock CLKr). It is a circuit which generates a sampling frequency fsamp at the time of generating. The reference frequency f0 is a fixed frequency, and is supplied from the fixed frequency oscillator 40 to the PLL circuit 47. Specifically, the PLL circuit 47 is adapted to generate a sampling frequency fsamp (= N × f0) by performing N-fold multiplication processing (N-multiplication) with respect to the reference frequency f0.

FIG. 6 is a block diagram showing a detailed configuration example of such a PLL circuit 47. As shown in FIG. 6, the PLL circuit 47 includes a frequency divider 470, a phase comparator 471, a loop filter 472, and a voltage controlled oscillator 473.

The frequency divider 470 is a circuit that functions as a so-called programmable divider, and divides the sampling frequency fsamp (= N × f0) described above by a frequency division ratio N. The phase comparator 471 is a circuit that performs phase comparison processing between the reference clock CLKr having a reference frequency f0 and the output signal from the frequency divider 470. The loop filter 472 is a filter circuit configured by using a so-called LPF (Low Pass Filter). The voltage controlled oscillator 473 is a circuit configured as a so-called VCO (Voltage Controlled Oscillator).

With such a configuration, in the PLL circuit 47, a sampling frequency fsamp (= N × f0) obtained by multiplying the reference frequency f0 by N is generated.

(Signal generator 48)
Although the details will be described later, the signal generation unit 48 generates a drive signal Sd having one or a plurality of drive waveforms by using a reference drive waveform that is a reference of the drive waveform in the drive signal Sd. It should be noted that such a "(one or a plurality of) drive waveforms" includes one or a plurality of "pulses" (pulse width Wp, voltage value Vp) described below, respectively.

Here, FIGS. 7 (A) to 7 (C) schematically show a configuration example of the drive signal Sd in a timing diagram. In FIGS. 7 (A) to 7 (C), the horizontal axis represents the time t, and the vertical axis represents the drive voltage Vd (positive voltage in this example) in the drive signal Sd.

First, the drive signal Sd shown in FIG. 7A has one pulse (pulse Pa), which is an example of a so-called “1 drop”. This pulse Pa is an ON period provided between the rising timing and the falling timing, and has the pulse width Wpa1 and the voltage value Vp1 as an example of the pulse width Wp and the voltage value Vp described above.

On the other hand, the drive signal Sd shown in FIG. 7B has the following two pulses (pulses Pa and Pb) as pulses to which the so-called "multi-pulse method" is applied (so-called "2 drops"). Example of the case). That is, two pulses Pa and Pb are provided as such a pulse (ON period). An OFF period (“OFF1”) is provided between these two pulses Pa and Pb. Further, as an example of the pulse width Wp and the voltage value Vp described above, the pulse Pa has the pulse width Wpa2 and the voltage value Vp2, and the pulse Pb has the pulse width Wpb2 and the voltage value Vp2.

Similarly, the drive signal Sd shown in FIG. 7C has the following three pulses (pulses Pa, Pb, Pc) as pulses to which the above-mentioned "multi-pulse method" is applied (so-called). Example of "3 drops"). That is, three pulses Pa, Pb, and Pc are provided as such pulses (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. Further, as an example of the pulse width Wp and the voltage value Vp described above, the pulse Pa has the pulse width Wpa3 and the voltage value Vp3, the pulse Pb has the pulse width Wpb3 and the voltage value Vp3, and the pulse Pc has the pulse width Wpc3 and the voltage value Vp3. It has a voltage value Vp3.

It should be noted that each pulse Pa, Pb, Pc in these drive signals Sd is a positive pulse that expands the above-mentioned discharge channel in the high state period and contracts the discharge channel in the low state period. It has become.

Here, although the details will be described later, the signal generation unit 48 sets the pulse width Wp in such a pulse (pulse Pa, Pb, Pc), and uses a drive waveform (pulse) having the set pulse width Wp. , The drive signal Sd is generated. Further, at this time, the signal generation unit 48 has a pulse width in the reference drive waveform (reference pulse width Wps: see FIG. 3) according to the sampling frequency fsamp set in the arithmetic processing unit 46 (and the PLL circuit 47) described above. The pulse width Wp is set by changing. The details of the process of generating the drive signal Sd by the signal generation unit 48 will be described later (FIGS. 10 to 14).

Here, the above-mentioned reference pulse width Wps corresponds to a specific example of the "pulse width in the reference drive waveform" in the present disclosure. Further, the "pulse" in the present disclosure is a concept including not only a rectangular wave as shown in FIG. 7, but also a waveform such as a trapezoidal wave, a triangular wave, and a step wave, and the same applies hereinafter.

(Drive unit 49)
The drive unit 49 applies the drive voltage Vd (drive signal Sd) described above to the actuator plate 42 to expand or contract the discharge channel described above, thereby injecting ink 9 from each nozzle hole Hn (spraying). (See FIGS. 2 and 3). Specifically, the drive unit 49 is configured to perform such an injection operation by using the drive signal Sd generated by the signal generation unit 48 described above.

[Operation and action / effect]
(A. Basic operation of printer 1)
In this printer 1, the recording operation (printing operation) of images, characters, etc. on the recording paper P is performed as follows. As an initial state, it is assumed that the ink 9 of the corresponding color (4 colors) is sufficiently filled in each of the four types of ink tanks 3 (3Y, 3M, 3C, 3K) shown in FIG. .. Further, the ink 9 in the ink tank 3 is filled in the inkjet head 4 via the circulation mechanism 5.

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 transferred between the grid rollers 21 and the pinch rollers 22 in the transport direction d (X). It is conveyed along the axial direction). Further, at the same time as such a transfer operation, the drive motor 633 in the drive mechanism 63 rotates the pulleys 631a and 631b to operate the endless belt 632. As a result, 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, each inkjet head 4 (4Y, 4M, 4C, 4K) appropriately ejects the four colors of ink 9 onto the recording paper P to record images, characters, and the like on the recording paper P. To.

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

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

At this time, the drive wall is bent and deformed in a V shape around the intermediate position in the depth direction of the drive wall. Then, due to such bending deformation of the drive wall, the discharge channel is deformed as if it were inflated. In this way, the volume of the discharge channel increases due to the bending deformation due to the piezoelectric thickness slip effect on the pair of drive walls. Then, as the volume of the ejection channel increases, the ink 9 is guided into the ejection channel.

Then, the ink 9 thus guided into the ejection channel becomes a pressure wave and propagates inside the ejection channel. Then, at the timing when the pressure wave reaches the nozzle hole Hn of the nozzle plate 41 (or the timing in the vicinity thereof), the drive voltage Vd applied to the drive electrode becomes 0 (zero) V. As a result, the drive wall is restored from the above-mentioned bending deformation state, and as a result, the volume of the discharge channel once increased is restored to the original volume.

In this way, in the process of returning the volume of the ejection channel to the original volume, the pressure inside the ejection channel increases, and the ink 9 in the ejection channel is pressurized. As a result, the droplet-shaped ink 9 is ejected to the outside (toward the recording paper P) through the nozzle hole Hn (see FIGS. 2 and 3). In this way, the ink jet head 4 ejects the ink 9 (ejection operation), and as a result, the recording operation (printing operation) of images, characters, etc. on the recording paper P is performed.

(C. Drive signal Sd generation operation)
Next, with reference to FIGS. 8 to 14 in addition to FIGS. 1 to 7, the operation (generation processing) of the drive signal Sd by the signal generation unit 48 described above will be described in detail in comparison with the comparative example. do.

(C-1. Comparative example)
FIG. 8 is a block diagram showing a schematic configuration example of the printer 101 as a liquid injection recording device according to a comparative example. The printer 101 of this comparative example corresponds to the printer 1 (see FIG. 3) of the present embodiment provided with the liquid injection head (inkjet head 104) according to the comparative example instead of the inkjet head 4. .. Further, the inkjet head 104 of this comparative example includes a drive unit 109 having a waveform information storage unit 108 together with the nozzle plate 41, the actuator plate 42, and the temperature detection unit 45 described above. That is, the inkjet head 104 is provided with the temperature control mechanism 43, the sound velocity measurement unit 44, the arithmetic processing unit 46, the PLL circuit 47, the frequency fixed oscillator 40, and the signal generation unit 48 in the inkjet head 4 (see FIG. 3). It corresponds to the case where the drive unit 109 is provided instead of the drive unit 49 while making it absent (omitted).

In the waveform information storage unit 108 of the drive unit 109, waveform information for setting a pulse (see pulses Pa to Pc in FIG. 7) in the drive signal Sd (for example, information on a drive waveform such as the reference drive waveform described above). However, it is stored in advance. Such waveform information is, for example, information calculated by manually observing the injection of ink 9 from each nozzle hole Hn in the nozzle plate 41 in advance. Then, the drive unit 109 sets the drive signal Sd using the waveform information stored in advance in the waveform information storage unit 108 based on the print data or the like input from the printer 101 main body, and sets the drive signal Sd as the actuator. It is designed to be applied to the plate 42.

By the way, in an inkjet head, it is generally known that the optimum pressure generation timing (on-pulse peak described later) and the pressure setting condition (driving voltage) differ greatly depending on the shape of the ejection channel and the physical property value of the ink 9 described above. Has been done. Therefore, in order to optimize such pressure generation timing and pressure setting conditions, in this comparative example, it is necessary to manually perform the ink injection observation (flying observation) as described above in advance. be. However, since waveform information using such ink 9 injection observation is created in advance by repeating trial and error, a huge amount of time is required, and sufficient experience and knowledge are required. Or, it is necessary to create the above-mentioned waveform information for each type of ink 9.

Further, in this comparative example, as described below, since the sampling frequency fsamp is fixed, it becomes as follows. That is, it is necessary to rewrite the information related to the drive waveform (information of the waveform information storage unit 108 described above) every time the pulse width Wp in the drive signal Sd is changed when the drive signal Sd is generated using the reference drive waveform. Occurs. While such information is being rewritten, the drive signal Sd cannot be set (drive waveform is switched), and the ink 9 injection operation cannot be performed, so that a printing dead time occurs. ..

Here, FIGS. 9 (A) to 9 (C) each show the adjustment method of the pulse width Wp according to the comparative example in a timing diagram. In FIGS. 9A to 9C, the horizontal axis represents time t and the vertical axis represents voltage (drive voltage Vd).

As shown in FIGS. 9A to 9C, in this comparative example, since the sampling frequency fsamp and the sampling period Tsamp (= 1 / fsamp) are fixed, the results are as follows. That is, the pulse width Wp can be adjusted only in this sampling period Tsamp unit. Specifically, for example, when the pulse width Wp = Wp101 shown in FIG. 9 (A) is used as a reference, the pulse width Wp = Wp102 shown in FIG. 9 (B) is a pulse for one unit of the sampling cycle Tsamp. The width Wp is adjusted to be small. Further, in the pulse width Wp = Wp103 shown in FIG. 9C, the pulse width Wp is adjusted to be larger by one unit of the sampling period Tsamp. As an example, when Wp = 7 [μs] and Tsamp = 100 [ns], the pulse width Wp can be adjusted only with a coarse width in (1/70) units of the pulse width Wp. become.

Further, although there is a demand for the printer user (end user, etc.) to freely change the ink 9, in the printer 101 of this comparative example, if the ink 9 is changed, the above-mentioned waveform information can be appropriately used. It will disappear. That is, the above-mentioned pressure generation timing and pressure setting conditions cannot be optimized, and the print image quality may deteriorate. Therefore, considering the risk of such deterioration of print quality, it can be said that the degree of freedom in selecting the ink 9 is practically very small for the user of the printer 101.

In this way, in this comparative example, in order to set the drive waveform (reference drive waveform, etc. described above) in the drive signal Sd, it is necessary to manually observe the injection of the ink 9 from the nozzle hole Hn in advance. There is a huge amount of time, effort, and dead time for printing, so it is as follows. That is, the convenience for the user may be impaired.

(C-2. Embodiment of this present)
Therefore, in the inkjet head 4 of the present embodiment, the signal generation unit 48 is designed to generate (automatically generate) the drive signal Sd at any time. Specifically, the signal generation unit 48 sets the pulse width Wp of the pulse (pulses Pa, Pb, Pc, etc. described above) in the drive signal Sd, and uses a pulse (drive waveform) having the set pulse width Wp. , The drive signal Sd is generated. Further, at this time, the signal generation unit 48 generates the drive signal Sd by using the above-mentioned table TB (see FIG. 5). Hereinafter, such a drive signal Sd generation process and the like will be described in detail.

FIG. 10 is a flow chart showing an example of such a table TB generation process (creation process). Further, FIG. 11 is a flow chart showing an example of the drive signal Sd generation processing and the like according to the present embodiment. Of the series of processes shown in FIG. 11 (steps S20 to S27 described later), each process of steps S21 to S26 described later corresponds to the process of generating the drive signal Sd.

(Steps S11 to S17: Table TB generation process)
First, in the series of processes shown in FIG. 10 (table TB generation process), first, the above-mentioned pumps (pressurizing pump 52a and suction pump 52b) are started to be between the ink tank 3 and the inkjet head 4. Then, the ink 9 is circulated (step S11). Next, using the temperature control mechanism 43, the temperature Ti of the ink 9 flowing in the ink supply tube 50a is set to the lower limit temperature Tmin within the predetermined temperature range ΔT (step S12).

Subsequently, in a state where the temperature Ti of the ink 9 is stable, the sound wave measuring unit 44 measures the propagation time Δt of the sound wave (acoustic signal Sac) described above and the temperature Ti of the ink 9 at that time, respectively (step S13). ). The temperature Ti of the ink 9 is set by the temperature detecting unit 442 in the sound velocity measuring unit 44.

Next, the arithmetic processing unit 46 is based on the propagation time Δt thus obtained and the above-mentioned distance Δd (physical distance from the sound wave transmitter 441a to the sound wave receiver 441b) known in advance. , The sound wave velocity Vs in the ink 9 is obtained by using the above-mentioned equation (1) (step S14). Then, the arithmetic processing unit 46 writes the correspondence relationship between the sound velocity Vs thus obtained and the temperature Ti of the ink 9 obtained in step S13 in the table TB (step S15).

Subsequently, the temperature Ti of the ink 9 flowing in the ink supply tube 50a is raised by a predetermined temperature from the above-mentioned lower limit temperature Tmin by using the temperature control mechanism 43 (step S16). Then, the arithmetic processing unit 46 determines whether or not the temperature Ti of the ink 9 after the temperature is raised is higher than the upper limit temperature Tmax within the temperature range ΔT described above (Ti> Tmax) (step S17). ).

Here, when it is determined that the temperature Ti of the ink 9 is equal to or less than the upper limit temperature Tmax (Ti ≦ Tmax) (step S17: N), the process is as follows. That is, in this case, it is determined that the table TB is incomplete (the table TB cannot be created from the lower limit temperature Tmin within the temperature range ΔT to the upper limit temperature Tmax), and the processes of steps S11 to S16 are performed. Will be repeated again.

On the other hand, when it is determined that the temperature Ti of the ink 9 is higher than the upper limit temperature Tmax (Ti> Tmax) (step S17: Y), the process is as follows. That is, in this case, it is determined that the table TB is completed (the table TB is created from the lower limit temperature Tmin within the temperature range ΔT to the upper limit temperature Tmax), and a series of processes (table) shown in FIG. 10 is determined. The TB generation process) is completed.

(Steps S20 to S27: Drive signal Sd generation processing, etc.)
On the other hand, in the series of processes shown in FIG. 11 (such as the process of generating the drive signal Sd), as a preliminary step, the arithmetic processing unit 46 determines whether or not the generation (update) of the drive signal Sd is necessary. (Step S20). Here, when it is determined that the drive signal Sd needs to be generated (step S20: Y), the process proceeds to the drive signal Sd generation process (steps S21 to S26) described below. On the other hand, when it is determined that the generation of the drive signal Sd is not necessary (step S20: N), the process proceeds to step S27 described later, and the ink 9 injection operation is performed based on the drive signal Sd at the current stage. It will be.

The case where the drive signal Sd needs to be generated (updated) 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 attached, or when a predetermined operation signal from the user is input to the printer 1, the non-ejection period (idle period) of the ink 9 is set. When it becomes more than a predetermined time, etc. may be mentioned.

Next, in the drive signal Sd generation process (steps S21 to S26), the signal generation unit 48 and the like perform the pulse width Wp setting process in the drive waveform as follows (see FIG. 11).

Here, in such a pulse width Wp setting process, first, the temperature detection unit 45 measures the actuator temperature Tpzzt (≈ temperature Ti of the ink 9) described above (step S21). Next, the arithmetic processing unit 46 uses the table TB generated by the series of processing shown in FIG. 10 while also considering the actuator temperature Tpzt thus obtained, and also uses a predetermined interpolation method. The sound velocity Vs in the ink 9 is obtained (step S22).

Subsequently, the arithmetic processing unit 46 obtains a pulse width Wp to be set in the drive waveform (pulse) of the drive signal Sd based on the sound velocity Vs in the ink 9 thus obtained (step S23). ).

Here, with reference to FIGS. 12 and 13, such a pulse width Wp setting method and the like will be described. 12 (A) to 12 (C) are schematic views for explaining the resonance in the discharge channel (discharge channel Ce) described above, respectively. Further, FIG. 13 is a schematic diagram showing an outline of a method for adjusting the pulse width Wp according to the embodiment of the present embodiment. In FIG. 13, the horizontal axis represents time t, and the vertical axis represents voltage (drive voltage Vd).

First, FIGS. 12 (A) to 12 (C) show the resonance states in the discharge channel Ce in the cases of M = 0, 1 and 2 described below, respectively.

Here, when considering to maximize the injection speed (discharge speed) of the ink 9, the drive is performed with respect to the channel length L (see FIGS. 12A to 12C) in the discharge channel Ce. The pulse width Wp in the signal Sd is defined by the following equation (2). Then, by using this equation (2), the pulse width Wp (on-pulse peak (AP): see FIG. 13) for maximizing the injection speed of the ink 9 is the sound velocity Vs or the like in the ink 9. Will be required based on. As specified by Eq. (2), in the case of resonance using an odd multiple of the speed of sound Vs, it is considered that the mechanical transmission efficiency is increased and the injection speed of the ink 9 is maximized, and in particular, M =. When it is 0, it is considered that the injection speed of the ink 9 becomes maximum.
AP = (2 x L) / {Vs x (2M + 1) (M = 0, 1, 2, ...) …… (2)

Incidentally, the above-mentioned AP corresponds to a period of 1/2 of the natural vibration cycle of the ink 9 in the ejection channel Ce (1 AP = (natural vibration cycle of the ink 9) / 2). When the pulse width Wp is set to this AP, the ejection speed (ejection efficiency) of the ink 9 is maximized when the normal one drop of ink 9 is ejected (one drop is ejected) as described above. Maximum). It should be noted that this AP is defined by, for example, the shape of the ejection channel Ce, the physical property value (specific gravity, etc.) of the ink 9.

Subsequently, the arithmetic processing unit 46 (and the PLL circuit 47) sets the sampling frequency fsamp based on the pulse width Wp to be set thus obtained (step S24). Then, the signal generation unit 48 sets the pulse width Wp by changing the pulse width (reference pulse width Wps) in the reference drive waveform according to the sampling frequency fsamp set in this way (step S25). ..

Here, FIGS. 14 (A) to 14 (C) each show an example of the pulse width Wp adjusting method according to the present embodiment in a timing diagram. In FIGS. 14 (A) to 14 (C), the horizontal axis represents time t, and the vertical axis represents voltage (drive voltage Vd).

As shown in FIGS. 14 (A) to 14 (C), in the present embodiment, unlike the above-mentioned comparative examples (FIGS. 9 (A) to 9 (C)), the sampling frequency fsamp and the sampling period Each Tsamp (= 1 / fsamp) is variable. Therefore, in the present embodiment, as described above, the pulse width Wp is adjusted by changing the reference pulse width Wps by utilizing the change in the sampling frequency fsamp.

Specifically, for example, when the pulse width Wp = Wp1 shown in FIG. 14 (A) is used as a reference (reference pulse width Wps = Wp1), the pulse width Wp = Wp2 shown in FIG. 14 (B) is as follows. In this way, the pulse width Wp is adjusted. That is, the value of the sampling frequency fsamp increases from fsamp1 to fsamp2, and the value of the sampling period Tsamp decreases accordingly from Tsamp1 to Tsamp2, so that the value of the pulse width Wp decreases from Wp1 to Wp2. (See FIGS. 14 (A) and 14 (B)).

On the other hand, in this case, in the pulse width Wp = Wp3 shown in FIG. 14C, the pulse width Wp is adjusted as follows. That is, the value of the sampling frequency fsamp decreases from fsamp1 to fsamp3, and the value of the sampling period Tsamp increases accordingly from Tsamp1 to Tsamp3, so that the value of the pulse width Wp increases from Wp1 to Wp3. (See FIGS. 14 (A) and 14 (C)).

In this way, in the present embodiment, unlike the above-mentioned comparative example (a method of adjusting the pulse width Wp by changing the number of units of the sampling period Tsamp), the following is achieved. That is, in the present embodiment, the magnitude of each sampling cycle Tsamp (sampling frequency fsamp) is changed (reference pulse width Wps is changed) while the unit number (reference drive waveform) of the sampling cycle Tsamp itself is fixed. Then, the pulse width Wp is adjusted.

Here, the magnitude of the sampling frequency fsamp (= f0 × N) can be adjusted in units of the reference frequency f0 (frequency of the reference clock CLKr: for example, about 1 [kHz]) input to the PLL circuit 47. Therefore, as described above, in the present embodiment, the pulse width Wp is adjusted with a fine width, as compared with the case of the above comparative example in which the pulse width Wp can be adjusted only with a coarse width in the sampling period Tsamp unit. (Fine adjustment) will be realized.

Next, the signal generation unit 48 uses the pulse (drive waveform) having the pulse width Wp set in this way to generate the drive signal Sd, for example, as shown in FIG. 7 described above (step S26). ). Then, the signal generation unit 48 applies such a drive signal Sd to the actuator plate 42 to inject ink 9 from the nozzle hole Hn (step S27). In this way, the ink spraying operation described above is performed.

This completes the series of processes shown in FIG. 11 (such as the process of generating the drive signal Sd).

(C-3. Action / effect)
In this way, in the inkjet head 4 of the present embodiment, the sampling frequency fsamp is set based on the predetermined arithmetic processing described above, and the reference pulse width Wps is changed according to the set sampling frequency fsamp. , The pulse width Wp of the drive waveform in the drive signal Sd is set. Then, a drive signal Sd is generated using a drive waveform (pulse) having a set pulse width Wp, and the generated drive signal Sd is applied to the actuator plate 42 to form a nozzle hole in the nozzle plate 41. Ink 9 is ejected from Hn. That is, a drive signal Sd is automatically generated in the inkjet head 4 by utilizing the fact that the pulse width Wp changes according to the setting of the sampling frequency fsamp, and the automatically generated drive signal Sd is used to generate ink 9. The injection operation is performed.

In this way, in the present embodiment, unlike the case of the above-mentioned comparative example and the like, the result is as follows. That is, in order to set the drive waveform (reference drive waveform and the like described above) in the drive signal Sd, it is not necessary to manually observe the injection of the ink 9 from the nozzle hole Hn in advance.

Further, in the present embodiment, unlike the case where the sampling frequency fsamp is fixed as in the comparative example (see FIGS. 9A to 9C), the result is as follows. That is, every time the pulse width Wp in the drive signal Sd is changed when the drive signal Sd is generated using the reference drive waveform, information on the drive waveform (information on the waveform information storage unit 108 in the comparative example, etc .: see FIG. 8). ) Does not need to be rewritten.

For these reasons, in the present embodiment, a huge amount of time, labor, and printing dead time are not required, and a drive waveform (drive signal Sd) suitable for the drive conditions at each time is automatically generated in the inkjet head 4 at any time. Will be generated.

From the 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-mentioned comparative example or the like. Further, for example, it is possible to significantly reduce the investment in measurement equipment and the fixed cost, which are separately required for the above-mentioned injection observation of the ink 9. 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. In addition, since it is not necessary to rewrite the information related to the drive waveform, the control becomes easy and the drive waveform can be switched quickly.

Further, in the present embodiment, the pulse width Wp to be set in the drive waveform (pulse) is obtained based on the sound velocity Vs in the ink 9, and the sampling frequency fsamp is based on the pulse width Wp to be set. Is set, so it becomes as follows. That is, as a result of generating a drive waveform more appropriately set with respect to the drive conditions, it is possible to improve the ejection stability of the ink 9.

Further, in the present embodiment, the sound velocity Vs in the ink 9 is obtained by using the table TB that defines the correspondence between the temperature Ti of the ink 9 and the sound velocity Vs in the ink 9, so that the driving condition is obtained. A more appropriately set drive waveform will be generated easily and quickly. Therefore, it is possible to further improve the convenience for the user.

In addition, in the present embodiment, the table TB is generated by measuring the sound velocity Vs in the ink 9 using the sound velocity measuring unit 44 while adjusting the temperature of the ink 9 by using the temperature adjusting mechanism 43. So, it will be as follows. That is, by setting the drive waveform (pulse) of the drive signal Sd using the table TB automatically generated in this way, the drive signal Sd that immediately responds to the change in the drive condition can be easily automatically performed. Can be generated. Therefore, it is possible to further improve the convenience for the user.

Further, in the present embodiment, since the sound velocity measuring unit 44 and the temperature adjusting mechanism 43 are provided in the inkjet head 4, respectively, the results are as follows. That is, the inkjet head 4 can automatically generate the table TB by itself, and the table TB is generated in a place close to the ink ejection environment (actuator plate 42 and nozzle plate 41). Therefore, the drive signal Sd suitable for the ink 9 can be easily generated in the inkjet head 4, and the convenience for the user can be further improved.

Further, in the present embodiment, since the circulation type inkjet head 4 that circulates and uses the ink 9 between the ink tank 3 and the inkjet head 4 is used, the result is as follows. That is, since the sound velocity Vs in the ink 9 can be measured in a state where the temperature Ti of the ink 9 is raised or lowered while the ink 9 is circulated, there is no waste due to the disposal of the ink 9, and the ink 9 is not wasted. Can be effectively used.

<2. Modification example>
Subsequently, a modification (modification examples 1 and 2) of the above embodiment will be described. The same components as those in the above embodiment are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

[Modification 1]
FIG. 15 is a block diagram showing a schematic configuration example of the printer 1a as the liquid injection recording device according to the modified example 1. The printer 1a of the modification 1 corresponds to the printer 1 of the embodiment in which the inkjet head 4a described below is provided instead of the inkjet head 4.

The printer 1a corresponds to a specific example of the "liquid injection recording device" in the present disclosure. Further, the inkjet head 4a corresponds to a specific example of the "liquid injection head" in the present disclosure.

In the inkjet head 4a of the modification 1, as shown in FIG. 15, in the inkjet head 4 (see FIG. 3) of the embodiment, the temperature control mechanism 43 and the sound velocity measuring unit 44 are respectively outside the inkjet head 4a. It corresponds to the one that is provided. That is, both the temperature control mechanism 43 and the sound velocity measuring unit 44 are arranged outside the inkjet head 4a in the printer 1a. Therefore, the inkjet head 4a of the modification 1 includes a nozzle plate 41, an actuator plate 42, a temperature detection unit 45, an arithmetic processing unit 46, a PLL circuit 47, a frequency fixed oscillator 40, a signal generation unit 48, and a drive unit 49. It will be provided (see FIG. 15).

Even in the modified example 1 having such a configuration, it is possible to obtain the same effect by basically the same operation as that of the embodiment.

Further, in particular, in this modification 1, since the temperature control mechanism 43 and the sound velocity measuring unit 44 are provided outside the inkjet head 4a, the configuration of the inkjet head 4a is simpler than that of the inkjet head 4 of the embodiment. It becomes possible to.

[Modification 2]
FIG. 16 is a block diagram showing a schematic configuration example of the printer 1b as the liquid injection recording device according to the modified example 2. The printer 1b of the modification 2 corresponds to the printer 1 of the embodiment in which the inkjet head 4b described below is provided instead of the inkjet head 4.

The printer 1b corresponds to a specific example of the "liquid injection recording device" in the present disclosure.

The inkjet head 4b of the modification 2 corresponds to the inkjet head 4 (see FIG. 3) of the embodiment as follows. That is, as shown in FIG. 16, in addition to the temperature control mechanism 43 and the sound velocity measurement unit 44, the arithmetic processing unit 46, the PLL circuit 47, the frequency fixed oscillator 40, and the signal generation unit 48 are also provided outside the inkjet head 4b. Has been done. That is, these temperature control mechanism 43, sound velocity measurement unit 44, arithmetic processing unit 46, PLL circuit 47, frequency fixed oscillator 40, and signal generation unit 48 are all arranged outside the inkjet head 4b in the printer 1b. .. Therefore, the inkjet head 4b of the second modification is provided with only the nozzle plate 41, the actuator plate 42, the temperature detection unit 45, and the drive unit 49 (see FIG. 16).

Even in the modified example 2 having such a configuration, since the printer 1b as a whole has the same configuration as the printer 1 and the printer 1a described so far, the same operations as those of the embodiment and the modified example 1 can be applied. , It is possible to obtain the same effect.

Further, in particular, in this modification 2, in addition to the temperature control mechanism 43 and the sound velocity measurement unit 44, the arithmetic processing unit 46, the PLL circuit 47, the frequency fixed oscillator 40, and the signal generation unit 48 are also provided outside the inkjet head 4b, respectively. Therefore, for example, the following effects can be obtained. That is, for example, even when an inkjet head 4b having an existing configuration is used, the temperature control mechanism 43, the sound velocity measurement unit 44, the arithmetic processing unit 46, the PLL circuit 47, the frequency fixed oscillator 40, and the signal generation unit are contained in the printer 1b. By arranging the 48, it is possible to realize the drive signal Sd generation processing and the like as described above.

<3. Other variants>
Although the present disclosure has been described above with reference to embodiments and modifications, 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, etc.) of each member in the printer and the inkjet head have been specifically described, but the description is not limited to the one described in the above-described embodiment and the like. , Other shapes, arrangements, numbers, etc. may be used. Specifically, in the above-described embodiment and the like, a shuttle type printer in which the inkjet head moves has been described as an example, but the present invention is not limited to this example, and for example, a single pass type printer in which the inkjet head is fixed is described. It may be. Further, in the above-described embodiment and the like, the case where the ink tank is housed in a predetermined housing has been described as an example, but the present invention is not limited to this example, and it seems that the ink tank is arranged outside the housing. You may do it. Further, at least one of the arithmetic processing unit 46, the PLL circuit 47, the fixed frequency oscillator 40, and the signal generation unit 48 is arranged in the printer (outside the inkjet head), and the rest is arranged in the inkjet head. You may do it.

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

Further, in the above-described embodiment and the like, a circulation type inkjet head in which the ink 9 is circulated and used between the ink tank and the inkjet head has been described as an example, but the present invention is not limited to this example. That is, for example, the present disclosure can be applied to a non-circulating inkjet head that uses ink 9 without circulating it.

In addition, in the above-described embodiment and the like, an example of the generation process of the drive signal Sd by the signal generation unit 48 and the like has been specifically described, but the example is not limited to the example given in the above-mentioned embodiment and the like. The driving signal Sd may be generated and the like may be performed by using the above method. Specifically, for example, in the above embodiment, the case where the drive signal Sd is generated after setting (automatically adjusting) the pulse width Wp in the drive waveform (pulse) has been described as an example. Not limited to. That is, for example, the drive signal Sd may be generated after setting both the pulse width Wp and the voltage value (peak value) Vp in the drive waveform.

Further, in the above embodiment, the case where the pulse (pulse Pa, Pb, Pc) that expands the volume in each discharge channel is a pulse (positive pulse) that expands in the high state period has been described. However, this is not the case. That is, not only in the case of a pulse that expands in the high state period and contracts in the low state period, but conversely, a pulse that expands in the low state period and contracts in the high state period (negative pulse). May be.

Further, for example, during the OFF period immediately after the ON period, a pulse for assisting the ejection of the droplet may be additionally applied. 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 for pulling back a part of the ejected droplet (auxiliary pulse). .. Further, 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). Even if a pulse for assisting the ejection of such droplets is added, it does not affect the contents (driving method, etc.) of the present disclosure described so far.

Further, the series of processes described in the above-described embodiment or the like may be performed by hardware (circuit) or software (program). When it is done by software, the software is composed of a group of programs for executing each function by a computer. Each program may be used by being preliminarily incorporated in the computer, for example, or may be installed and used in the computer from a network or a recording medium.

Further, in the above-described embodiment and the like, the printer 1 (inkjet printer) has been described as a specific example of the "liquid injection recording device" in the present disclosure, but the present invention is not limited to this example, and other than the inkjet printer. The present disclosure can also be applied to the device. In other words, the "liquid injection head" (inkjet head) of the present disclosure may be applied to devices other than the inkjet printer. Specifically, for example, the "liquid injection 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 so far may be applied in any combination.

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

In addition, the present disclosure may have the following structure.
(1)
An injection unit having multiple nozzles for injecting liquid,
A drive unit that injects the liquid from the nozzle by applying a drive signal having one or more drive waveforms to the injection unit.
An arithmetic processing unit that performs predetermined arithmetic processing, and
It is provided with a signal generation unit that generates the drive signal by using the reference drive waveform that is the reference of the drive waveform.
The arithmetic processing unit sets a sampling frequency at the time of generating the drive signal based on the arithmetic processing.
The signal generation unit
By changing the pulse width in the reference drive waveform according to the sampling frequency set in the arithmetic processing unit, the pulse width in the drive waveform is set and the pulse width is set.
A liquid injection head that generates the drive signal using the drive waveform having the set pulse width.
(2)
The arithmetic processing unit is used as the arithmetic processing.
The liquid injection according to (1) above, wherein the pulse width to be set in the drive waveform is obtained based on the speed of sound in the liquid, and the sampling frequency is set based on the pulse width to be set. head.
(3)
The liquid injection head according to (2) above, wherein the arithmetic processing unit obtains the speed of sound in the liquid by using a table that defines the correspondence between the temperature of the liquid and the speed of sound in the liquid.
(4)
The liquid injection head according to (3) above, wherein the table is generated by using the sound velocity measuring unit for measuring the sound velocity in the liquid and the temperature adjusting mechanism for adjusting the temperature of the liquid.
(5)
The liquid injection head according to (4) above, further comprising the sound velocity measuring unit and the temperature control mechanism.
(6)
A liquid injection recording device provided with the liquid injection head according to any one of (1) to (5) above.
(7)
A system that generates a drive signal having one or more drive waveforms applied to an injection unit having a plurality of nozzles for injecting a liquid.
An arithmetic processing unit that performs predetermined arithmetic processing, and
It is provided with a signal generation unit that generates the drive signal by using the reference drive waveform that is the reference of the drive waveform.
The arithmetic processing unit sets a sampling frequency at the time of generating the drive signal based on the arithmetic processing.
The signal generation unit
By changing the pulse width in the reference drive waveform according to the sampling frequency set in the arithmetic processing unit, the pulse width in the drive waveform is set and the pulse width is set.
A drive signal generation system that generates the drive signal using the drive waveform having the set pulse width.

1,1a, 1b ... Printer, 10 ... Housing, 2a, 2b ... Conveyance mechanism, 21 ... Grid roller, 22 ... Pinch roller, 3 (3Y, 3M, 3C, 3K) ... Ink tank, 4 (4Y, 4M, 4C) , 4K), 4a, 4b ... inkjet head, 40 ... fixed frequency oscillator, 41 ... nozzle plate, 42 ... actuator plate, 43 ... temperature control mechanism, 44 ... sound velocity measuring unit, 440 ... flow path, 441a ... sound transmitter, 441b ... Sonic receiver, 442, 45 ... Temperature detector, 46 ... Arithmetic processing unit, 47 ... PLL circuit, 470 ... Divider (programmable divider), 471 ... Phase comparator, 472 ... Loop filter, 473 ... Voltage Control oscillator, 48 ... signal generation unit, 49 ... drive unit, 5 ... circulation mechanism, 50 ... circulation flow path, 50a ... ink supply pipe, 50b ... ink discharge pipe, 52a ... pressurizing pump, 52b ... suction pump, 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, Tpzz ... actuator temperature, Ti ... temperature, Tmin ... lower limit temperature, Tmax ... upper limit temperature, ΔT ... temperature range, Wp (Wp1, Wp2, Wp3) ) ... Pulse width, Wps ... Reference pulse width, Vp ... Voltage value (peak value), Vs ... Sound velocity, Pa, Pb, Pc ... Pulse, Sac, Sacin, Sacout ... Acoustic signal, f0 ... Reference frequency, fsamp (fsamp1, fsamp1, fsamp2, fsamp3) ... sampling frequency, Tsamp (Tsamp1, Tsamp2, Tsamp3) ... sampling cycle, CLKr ... reference clock, N ... frequency division ratio (multiplication), Δd ... distance, L ... channel length, TB ... table, t ... Time, t1, t2 ... Timing, Δt ... Propagation time.

Claims (7)

An injection unit having multiple nozzles for injecting liquid,
A drive unit that injects the liquid from the nozzle by applying a drive signal having one or more drive waveforms to the injection unit.
An arithmetic processing unit that performs predetermined arithmetic processing, and
It is provided with a signal generation unit that generates the drive signal by using the reference drive waveform that is the reference of the drive waveform.
The arithmetic processing unit sets a sampling frequency at the time of generating the drive signal based on the arithmetic processing.
The signal generation unit
By changing the pulse width in the reference drive waveform according to the sampling frequency set in the arithmetic processing unit, the pulse width in the drive waveform is set and the pulse width is set.
A liquid injection head that generates the drive signal using the drive waveform having the set pulse width. The arithmetic processing unit is used as the arithmetic processing.
The liquid injection head according to claim 1, wherein the pulse width to be set in the drive waveform is obtained based on the sound velocity in the liquid, and the sampling frequency is set based on the pulse width to be set. .. The liquid injection head according to claim 2, wherein the arithmetic processing unit uses a table that defines a correspondence between the temperature of the liquid and the speed of sound in the liquid to obtain the speed of sound in the liquid. The liquid injection head according to claim 3, wherein the table is generated by using the sound velocity measuring unit for measuring the sound velocity in the liquid and the temperature adjusting mechanism for adjusting the temperature of the liquid. The liquid injection head according to claim 4, further comprising the sound velocity measuring unit and the temperature adjusting mechanism. A liquid injection recording device including the liquid injection head according to any one of claims 1 to 5. A system that generates a drive signal having one or more drive waveforms applied to an injection unit having a plurality of nozzles for injecting a liquid.
An arithmetic processing unit that performs predetermined arithmetic processing, and
It is provided with a signal generation unit that generates the drive signal by using the reference drive waveform that is the reference of the drive waveform.
The arithmetic processing unit sets a sampling frequency at the time of generating the drive signal based on the arithmetic processing.
The signal generation unit
By changing the pulse width in the reference drive waveform according to the sampling frequency set in the arithmetic processing unit, the pulse width in the drive waveform is set and the pulse width is set.
A drive signal generation system that generates the drive signal using the drive waveform having the set pulse width.

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