JP6969170B2 - Liquid discharge head, liquid discharge device, drive control circuit of liquid discharge device, drive method of liquid discharge device - Google Patents

Description

The present invention relates to a technique for ejecting a liquid such as ink.

In the liquid discharge head that discharges the liquid such as ink from the nozzle by vibrating the pressure in the pressure chamber filled with the liquid such as ink by the drive element, the discharge amount of the liquid changes depending on the natural vibration cycle of the liquid in the pressure chamber. Therefore, the drive waveform of the drive element may be set in consideration of this. However, for example, in Patent Document 1, when UV ink containing a photocurable resin is ejected, the vibrating plate (sealing plate) constituting the wall surface of the pressure chamber is gradually deteriorated by the UV ink, and the compliance is changed. It has been pointed out that the natural vibration cycle of the ink in the pressure chamber fluctuates with time, and the ink cannot be stably ejected with the initially set drive waveform (drive pulse) of the drive element. Therefore, in Patent Document 1, by correcting the drive waveform according to the elapsed time from filling the pressure chamber with ink, even if the natural vibration cycle of the ink in the pressure chamber fluctuates with time, the ink is released. It is designed to be discharged stably.

Japanese Unexamined Patent Publication No. 2010-167724

By the way, if the drive waveform having the resonance frequency of the diaphragm described above is continuously applied to the drive element, cracks may occur in the diaphragm and the drive element and the drive element may be damaged. Therefore, at the time of manufacture, a drive waveform is set so as not to be the resonance frequency of the diaphragm. However, there is a possibility that air bubbles may be mixed in the pressure chamber, the liquid storage chamber, or the like during printing, and if the air bubbles are mixed, the resonance frequency of the diaphragm suddenly fluctuates. Therefore, the frequency of the drive waveform matches the fluctuating resonance frequency, and there is a risk that the diaphragm and the drive element will be cracked and damaged. If the diaphragm or the driving element is damaged, printing cannot be continued anymore, and there is a problem that downtime occurs. However, in Patent Document 1, since the sudden fluctuation of the resonance frequency of the diaphragm due to the mixing of air bubbles or the like is not taken into consideration, there is a possibility that such a problem cannot be completely solved. In consideration of the above circumstances, it is an object of the present invention that stable liquid discharge can be continued regardless of the state of the liquid discharge head such as the presence or absence of air bubbles, and the occurrence of downtime can be suppressed.

[Aspect 1]
In order to solve the above problems, the drive control circuit of the liquid discharge device according to the preferred embodiment (aspect 1) of the present invention discharges the liquid by varying the pressure in the internal space filled with the liquid by the drive element. A drive control circuit for a liquid discharge device including a liquid discharge head, wherein the liquid discharge head has a first terminal to which a drive waveform signal having a drive waveform for driving a drive element is input, and a state of the liquid discharge head. The drive waveform signal includes a first drive waveform signal and a second drive waveform signal having different drive waveforms, and the drive control circuit includes a second terminal for outputting a state signal indicating the above. If the status signal from the second terminal is a predetermined signal, the first drive waveform signal is input to the first terminal, and if the status signal from the second terminal is not a predetermined signal, the first terminal is used. The second drive waveform signal is input.
According to the above aspect, by applying a drive waveform to the drive element to vibrate the diaphragm or the like, the pressure in the internal space of the liquid discharge head can be changed to discharge the liquid. At that time, it is possible to vibrate the diaphragm by applying a different drive waveform to the drive element depending on the state of the liquid discharge head indicated by the state signal. Therefore, stable liquid discharge can be continued, and the occurrence of downtime can be suppressed.
In this case, since the state of the liquid discharge head changes depending on whether or not there are air bubbles or the like in the internal space of the liquid discharge head (pressure chamber, liquid storage chamber, etc.), the state signal can also be changed. For example, it is possible that the state signal with bubbles is a predetermined signal and the state signal without bubbles is not a predetermined signal. Thereby, the presence or absence of air bubbles can be determined depending on whether or not the state signal is a predetermined signal. In this case, when the state signal is a predetermined signal (for example, when there is no bubble), the first drive waveform signal is input to the first terminal, and when the state signal is not a predetermined signal (for example, when there is no bubble). A second drive waveform signal having a drive waveform different from that of the first drive waveform signal is input to the first terminal. In this way, it is possible to vibrate the diaphragm by applying different drive waveforms to the drive element depending on the state of the liquid discharge head (presence or absence of air bubbles). Therefore, even if the resonance frequency of the diaphragm fluctuates depending on the presence or absence of air bubbles, the occurrence of cracks in the diaphragm and the driving element can be suppressed, so that stable liquid discharge can be continued regardless of the presence or absence of air bubbles, and the liquid can be discharged down. The generation of time can be suppressed.

[Aspect 2]
In order to solve the above problems, the drive control circuit of the liquid discharge device according to the preferred embodiment (aspect 2) of the present invention discharges the liquid by varying the pressure in the internal space filled with the liquid by the drive element. A drive control circuit for a liquid discharge device including a liquid discharge head, wherein the liquid discharge head has a first terminal for inputting a drive waveform signal having a plurality of drive waveforms for driving the drive element, and a liquid discharge head. A head drive circuit having a second terminal for outputting a state signal indicating the state of the above, comprising a head drive circuit for outputting a drive signal having a drive waveform selected from the drive waveform signal to a drive element, and driving The signal includes a first drive signal and a second drive signal having different drive waveforms, and the drive control circuit sends the first drive signal to the drive element when the state signal from the second terminal is a predetermined signal. If the status signal from the second terminal is not a predetermined signal, the second drive signal is input to the drive element.
According to the above aspect, by applying a drive waveform to the drive element to vibrate the diaphragm or the like, the pressure in the internal space of the liquid discharge head can be changed to discharge the liquid. At that time, it is possible to vibrate the diaphragm by applying a different drive waveform to the drive element depending on the state of the liquid discharge head indicated by the state signal. Therefore, stable liquid discharge can be continued, and the occurrence of downtime can be suppressed.
In this case, for example, the state signal in the presence of bubbles may be a predetermined signal, and the state signal in the absence of bubbles may not be a predetermined signal. As a result, when the state signal is a predetermined signal (for example, when there is no bubble), the first drive signal is output to the driving element, and when the state signal is not a predetermined signal (for example, when there is no bubble), the first drive signal is output to the drive element. , The second drive signal having a drive waveform different from the drive waveform of the first drive signal is output to the drive element. In this way, different drive waveforms can be applied to the drive element to vibrate the diaphragm depending on the presence or absence of the state of the liquid discharge head (presence or absence of air bubbles). Therefore, even if the resonance frequency of the diaphragm fluctuates depending on the presence or absence of air bubbles, the occurrence of cracks in the diaphragm and the driving element can be suppressed, so that stable liquid discharge can be continued regardless of the presence or absence of air bubbles, and the liquid can be discharged down. The generation of time can be suppressed.

[Aspect 3]
In order to solve the above problems, the drive control circuit of the liquid discharge device according to the preferred embodiment (aspect 3) of the present invention discharges the liquid by varying the pressure in the internal space filled with the liquid by the drive element. A drive control circuit for a liquid discharge device including a liquid discharge head, wherein the liquid discharge head has a first terminal for inputting a drive waveform signal having a plurality of drive waveforms for driving the drive element, and a liquid discharge head. It is provided with a head drive circuit having a second terminal for outputting a state signal indicating the state of, and a third terminal for inputting a selection signal for selecting a drive waveform to be applied to the drive element from the drive waveform signal. The selection signal includes a first selection signal and a second selection signal for selecting different drive waveforms, and the drive control circuit is connected to the third terminal when the state signal from the second terminal is a predetermined signal. The first selection signal is input, and if the state signal from the second terminal is not a predetermined signal, the second selection signal is input to the third terminal.
According to the above aspect, by applying a drive waveform to the drive element to vibrate the diaphragm or the like, the pressure in the internal space of the liquid discharge head can be changed to discharge the liquid. At that time, it is possible to vibrate the diaphragm by applying a different drive waveform to the drive element depending on the state of the liquid discharge head indicated by the state signal. Therefore, stable liquid discharge can be continued, and the occurrence of downtime can be suppressed.
In this case, for example, the state signal in the presence of bubbles may be a predetermined signal, and the state signal in the absence of bubbles may not be a predetermined signal. As a result, when the state signal is a predetermined signal (for example, when there is no bubble), the first selection signal is output to the third terminal, and when the state signal is not a predetermined signal (for example, when there is no bubble). Is output to the third terminal a second selection signal that selects a drive waveform different from the drive waveform selected by the first selection signal. In this way, different drive waveforms can be applied to the drive element to vibrate the diaphragm depending on the presence or absence of the state of the liquid discharge head (presence or absence of air bubbles). Therefore, even if the resonance frequency of the diaphragm fluctuates depending on the presence or absence of air bubbles, the occurrence of cracks in the diaphragm and the driving element can be suppressed, so that stable liquid discharge can be continued regardless of the presence or absence of air bubbles, and the liquid can be discharged down. The generation of time can be suppressed.

[Aspect 4]
In any of the preferred examples of any of aspects 1 to 3 (aspect 4), the different drive waveform is a waveform of a voltage signal, which is the slope of the waveform, the maximum value of the potential, the minimum value of the potential, the amplitude of the waveform, and the waveform. At least one or more of the frequencies are different. According to the above aspects, by switching a drive waveform in which at least one of the waveform gradient, the maximum value of the potential, the minimum value of the potential, the amplitude of the waveform, and the frequency of the waveform is different, the presence or absence of bubbles and the amount of bubbles can be determined. It is possible to discharge the liquid with different drive waveforms. Further, by making the inclination of the waveform different, it is possible to change the discharge amount of the liquid to be discharged and the size of the droplet when there is a liquid. Further, if the amplitude of the drive waveform is increased when the amount of bubbles is large, droplets can be ejected even if the pressure fluctuation is absorbed by the bubbles. Further, by preventing the amplitude of the drive waveform from becoming too small, it is possible to prevent pressure fluctuations from being absorbed and forming mist.

[Aspect 5]
In any of the preferred examples (aspect 5) of any one of aspects 1 to 4, the liquid discharge head is arranged between the drive element, the pressure chamber, and the pressure chamber and the drive element to form a wall surface of the internal space. A diaphragm that vibrates depending on the drive element is provided, and the different drive waveforms are waveforms in which the presence or absence of resonance of the diaphragm is switched. According to the above aspect, since the different drive waveforms are waveforms in which the presence or absence of resonance of the vibrating plate is switched, even if the vibrating plate resonates with one driving waveform, the vibrating plate does not resonate with the other driving waveform. can do. Further, according to this aspect, since the resonance of the diaphragm can be suppressed, the occurrence of cracks can be suppressed even if the diaphragm is made into a thin film. Therefore, by making the diaphragm a thin film, high-speed and high-quality printing becomes possible, and the liquid discharge head can be easily miniaturized.

[Aspect 6]
In any of the preferred examples (Aspect 6) of Aspects 1 to 5, the liquid discharge device includes a display unit that displays the operation mode of the liquid discharge device, and changes the operation mode to be displayed on the display unit according to the status signal. do. According to the above aspect, since the operation mode displayed on the display unit is changed according to the state signal, the operation mode that can be executed by the user can be limited according to the state signal. Examples of the operation mode of this embodiment include a high-quality mode and a high-speed mode, a mode with complementary printing and a mode without complementary printing. For example, when the state signal is a predetermined signal (without bubbles), one mode is displayed, and when the state signal is not a predetermined signal (with bubbles), the other mode is displayed. Since the drive waveform used differs depending on the operation mode, it is possible to prevent the diaphragm from resonating even if the resonance frequency of the diaphragm fluctuates.

[Aspect 7]
In any of the preferred examples (Aspect 7) of Aspects 1 to 6, different drive waveforms are applied to the drive element according to the amount of air bubbles in the internal space of the liquid discharge head. According to the above aspect, since different drive waveforms are applied to the drive element according to the amount of air bubbles in the internal space of the liquid discharge head, stable liquid discharge is continued regardless of the amount of air bubbles. Can be done.

[Aspect 8]
In any of the preferred examples (aspect 8) of aspects 1 to 7, different drive waveforms are applied to the drive element according to the continuous application time of the drive waveform to the drive element. According to the above aspect, since different drive waveforms are applied to the drive element according to the continuous application time of the drive waveform to the drive element, the temperature of the liquid discharge head rises due to the continuous application time of the drive waveform to generate bubbles. Even if the resonance frequency of the diaphragm fluctuates due to the increase in the value, the occurrence of cracks due to the resonance of the diaphragm can be suppressed.

[Aspect 9]
In a preferred example of the eighth aspect (aspect 9), a different drive waveform is applied to the drive element according to the position of the bubble contained in the internal space of the liquid discharge head. According to the above aspect, since different drive waveforms are applied to the drive element according to the position of the bubble contained in the internal space of the liquid discharge head, even if the resonance frequency of the diaphragm changes depending on the position of the bubble, The generation of cracks due to the resonance of the diaphragm can be suppressed.

[Aspect 10]
In a preferred example (aspect 10) of any one of aspects 1 to 9, the liquid discharge device has a maximum width capable of serial printing of 24 inches or more and 75 inches or less. According to the above aspect, even when the maximum width in which serial printing is possible is 24 inches or more and 75 inches or less, the generation of cracks due to the resonance of the diaphragm can be suppressed. Further, since the maximum width capable of serial printing is 24 inches or more and 75 inches or less, the total length of the signal line through which the drive signal or the like propagates can be about 1 m to 3 m, so that the maximum width capable of serial printing is increased. Compared with the case of 75 inches or more, the impedance and inductance of the signal line can be reduced. Therefore, it is possible to suppress the occurrence of failure or malfunction due to overshoot or undershoot of the drive signal.

[Aspect 11]
In a preferred example of aspect 10 (aspect 11), the liquid ejection device corresponds to any medium of 24 inches, 36 inches, 44 inches, and 64 inches as a width capable of serial printing. According to the above aspect, since it is compatible with any of 24 inch, 36 inch, 44 inch, and 64 inch media, it is possible to suppress the generation of cracks due to the resonance of the diaphragm even when printing on these media. ..

[Aspect 12]
In any of the preferred examples of Aspects 1 to 11 (Aspect 12), the liquid discharge head discharges the liquid with a drive waveform having a frequency of 30 kHz or higher. According to the above aspect, since the liquid is discharged with a drive waveform having a high frequency of 30 kHz or more, printing can be performed at high speed, and even when the resonance frequency of the diaphragm is generated at 30 kHz or more, the diaphragm does not resonate. Can be. Therefore, even in the case of high-speed printing in which the frequency of the drive waveform is 30 kHz or more, stable liquid discharge can be continued regardless of the presence or absence of air bubbles, and the occurrence of downtime can be suppressed.

[Aspect 13]
In order to solve the above problems, the liquid discharge device according to the preferred embodiment (aspect 13) of the present invention is a liquid discharge head that discharges a liquid by varying the pressure in the internal space filled with the liquid by a driving element. And a drive control circuit that applies a drive waveform to the drive element, and the drive control circuit switches the drive waveform applied to the drive element according to the amount of air bubbles in the internal space of the liquid discharge head. According to the above aspect, since the drive control circuit switches the drive waveform applied to the drive element according to the amount of air bubbles in the internal space of the liquid discharge head, a different drive waveform is applied to the drive element according to the amount of air bubbles. The diaphragm can be vibrated. Therefore, stable liquid discharge can be continued regardless of the amount of air bubbles in the internal space of the liquid discharge head, and the occurrence of downtime can be suppressed.

[Aspect 14]
In order to solve the above problems, the liquid discharge head according to the preferred embodiment (aspect 14) of the present invention is a liquid discharge head that discharges a liquid by varying the pressure in the internal space filled with the liquid by a driving element. Therefore, the drive waveform applied to the drive element is switched according to the amount of air bubbles in the internal space of the liquid discharge head. According to the above aspect, since the drive waveform applied to the drive element is switched according to the amount of air bubbles in the internal space of the liquid discharge head, a different drive waveform is driven according to the amount of air bubbles in the internal space of the liquid discharge head. The diaphragm can be vibrated by applying it to the element. Therefore, stable liquid discharge can be continued regardless of the amount of air bubbles in the internal space of the liquid discharge head, and the occurrence of downtime can be suppressed.

[Aspect 15]
In order to solve the above problems, the method according to a preferred embodiment (aspect 15) of the present invention is a method for driving a liquid discharge device, in which the liquid discharge device drives the pressure in the internal space filled with the liquid. A liquid discharge head that discharges a liquid by fluctuating depending on the element and a drive control circuit that applies a drive waveform to the drive element are provided, and the drive control circuit is provided according to the amount of air bubbles in the internal space of the liquid discharge head. The drive waveform applied to the drive element is switched. According to the above aspect, since the drive control circuit switches the drive waveform applied to the drive element according to the amount of air bubbles in the internal space of the liquid discharge head, a different drive waveform is applied to the drive element according to the amount of air bubbles. The diaphragm can be vibrated. Therefore, stable liquid discharge can be continued regardless of the amount of air bubbles in the internal space of the liquid discharge head, and the occurrence of downtime can be suppressed.

[Aspect 16]
In order to solve the above problems, the method according to a preferred embodiment (aspect 16) of the present invention is a method for driving a liquid discharge device, in which the liquid discharge device drives the pressure in the internal space filled with the liquid. A liquid discharge head that discharges liquid by fluctuating depending on the element, and a first mode and a second mode as operation modes in which different drive waveforms are applied to the drive element according to the amount of bubbles in the internal space of the liquid discharge head. The first step of storing the drive waveform of the first mode in the storage device and the second step of storing the drive waveform of the second mode in the storage device are provided with a drive control circuit for switching and a storage device for storing the drive waveform. And have. According to the above aspect, the drive waveform of the first mode and the drive waveform of the second mode can be freely stored in the storage device, which is convenient. Further, since the liquid can be discharged in the mode of the drive waveform stored in the storage device, it is possible to print according to the user's preference while suppressing the occurrence of downtime.

It is a block diagram of the liquid discharge apparatus which concerns on 1st Embodiment of this invention. It is a functional block diagram for demonstrating the drive control circuit of a liquid discharge device. It is sectional drawing of the liquid discharge part. It is a figure for demonstrating the operation mode of 1st Embodiment. It is a flowchart which shows the control at the time of printing of a liquid discharge device. It is a figure for demonstrating the operation mode of 2nd Embodiment. It is a figure for demonstrating the operation mode of 3rd Embodiment. It is a figure for demonstrating the drive waveform signal of the operation mode of 4th Embodiment. It is a figure for demonstrating the drive waveform selected in the operation mode of 4th Embodiment. It is a figure for demonstrating the drive waveform signal of the operation mode of 5th Embodiment. It is a figure for demonstrating the drive waveform selected in the operation mode of 5th Embodiment.

<First Embodiment>
FIG. 1 is a partial configuration diagram of a liquid discharge device 10 according to a first embodiment of the present invention. The liquid ejection device 10 of the present embodiment is an inkjet printing apparatus that ejects ink, which is an example of a liquid, onto a medium 12 such as printing paper. The liquid discharge device 10 shown in FIG. 1 includes a control unit 20, a transfer mechanism 22, a carriage 24, and a liquid discharge head 26. Although FIG. 1 illustrates a case where one liquid discharge head 26 is mounted on the carriage 24, the present invention is not limited to this, and a plurality of liquid discharge heads 26 may be mounted on the carriage 24. A liquid container (cartridge) 14 for storing ink is attached to the liquid ejection device 10.

The liquid container 14 is an ink tank type cartridge composed of a box-shaped container that can be attached to and detached from the main body of the liquid ejection device 10. The liquid container 14 is not limited to the box-shaped container, and may be an ink pack type cartridge composed of a bag-shaped container. Ink is stored in the liquid container 14. The ink may be black ink or color ink. The ink stored in the liquid container 14 is supplied (pumped) to the liquid discharge head 26 by a pump (not shown).

The control unit 20 includes a control device 202 such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array) and a storage device 203 such as a semiconductor memory, and stores a control program in the storage device 203. By executing the control device 202, each element of the liquid discharge device 10 is comprehensively controlled. As shown in FIG. 1, print data G representing an image to be formed on the medium 12 is input to the control unit 20 from an external device (not shown) such as a host computer. The control unit 20 controls each element of the liquid ejection device 10 so that the image specified by the print data G is formed on the medium 12.

The transport mechanism 22 transports the medium 12 in the Y direction under the control of the control unit 20. The liquid ejection head 26 is mounted on a substantially box-shaped carriage 24, and ejects ink supplied from the liquid container 14 to the medium 12 under the control of the control unit 20. The control unit 20 reciprocates the carriage 24 along the X direction intersecting the Y direction. A desired image is formed on the surface of the medium 12 by the liquid ejection head 26 ejecting ink to the medium 12 in parallel with the transfer of the medium 12 by the transport mechanism 22 and the repetitive reciprocation of the carriage 24. It is also possible to mount the liquid container 14 on the carriage 24 together with the liquid discharge head 26.

A nozzle row is arranged on the discharge surface (the surface facing the medium 12) 260 of the liquid discharge head 26. The nozzle row is a set of a plurality of nozzles N arranged linearly along the Y direction. The ink supplied from the liquid container 14 is ejected from the nozzle N. The number and arrangement of the nozzle rows are not limited to those exemplified, and two or more nozzle rows may be arranged on the discharge surface 260 of the liquid discharge head 26, for example, a plurality of nozzle rows may be arranged in a staggered arrangement or staggered. It can also be an array. The direction perpendicular to the XY plane (plane parallel to the surface of the medium 12) is referred to as the Z direction.

FIG. 2 is a functional configuration diagram for explaining the drive control circuit 21 of the liquid discharge device 10. In FIG. 2, the transport mechanism 22, the carriage 24, and the like are not shown for convenience. The liquid discharge device 10 includes a drive control circuit 21. The drive control circuit 21 is electrically connected to the head drive circuit 262 by terminals P1 to P6 described later. The drive control circuit 21 is provided in the control unit 20, and the head drive circuit 262 is provided in the liquid discharge head 26. However, the head drive circuit 262 may be provided in addition to the liquid discharge head 26. When the control device 202 executes the control program, the control device 202 functions as a drive signal generation unit 40, a control unit 50, and a determination unit 52. The drive signal generation unit 40, the control unit 50, and the determination unit 52 may be configured by an electronic circuit. The control unit 50 may be a processor 50. The control unit 50 controls the drive signal generation unit 40. The data table C is stored in the storage device 203. The data table C may be stored in the memory included in the storage device 203. The drive signal generation unit 40 generates a drive waveform signal COM. The drive waveform signal COM is, for example, a waveform of a voltage signal including drive waveforms W1 and W2 as shown in FIG. 4, that is, a plurality of potentials (VL, VH, etc.) having a potential difference with respect to a reference potential (intermediate potential) VM. .. The drive waveform of the drive waveform signal COM is generated every predetermined period T. The period T of the drive waveform signal COM corresponds to one pixel.

The piezoelectric element 74 of the present embodiment is driven by a plurality of operation modes, and a drive waveform of a drive waveform signal COM different for each operation mode is applied to the piezoelectric element 74. FIG. 4 illustrates the drive waveform W1 of the first drive waveform signal COM1 in the first mode and the drive waveform W2 of the second drive waveform signal COM2 in the second mode as operation modes. The data for generating the drive waveform signal COM (for example, voltage data) is stored in the data table C. When the drive waveform signal COM is generated, the control unit 50 reads the data corresponding to the drive waveform included in the drive waveform signal COM from the data table C and generates it by the drive signal generation unit 40. The details of these operation modes and the drive waveforms W1 and W2 will be described later.

The operation mode is not limited to the first mode and the second mode, and each operation mode can be freely selected and executed by the user. For example, as shown in FIG. 2, the liquid discharge device 10 includes an operation panel 60 composed of a touch panel, and the operation panel 60 includes a display unit 62. The operation panel 60 is an operation panel on which various operations can be performed by the user, and a plurality of buttons (not shown) are displayed on the display unit 62. The display unit 62 also displays an operation mode selection button, and the user touches the operation mode button displayed on the display unit 62 to execute the operation mode.

As shown in FIG. 2, the liquid discharge head 26 includes a head drive circuit 262 and a liquid discharge unit 264. The head drive circuit 262 drives the liquid discharge unit 264 under the control of the control unit 20. The liquid ejection unit 264 ejects the ink supplied from the liquid container 14 from the plurality of nozzles N to the medium 12. The liquid discharge unit 264 includes a plurality of discharge units 266 corresponding to the plurality of nozzles N. Each ejection unit 266 ejects ink according to the drive signal V output from the head drive circuit 262.

The drive control circuit 21 includes a drive waveform signal COM generated by the drive signal generation unit 40 and a selection signal (print signal) SI that specifies the presence or absence of ink ejection for each nozzle N according to the drive waveform signal COM and the print data G. Is input to the head drive circuit 262. The selection signal SI includes data for specifying selection and non-selection of the drive waveform W included in the drive waveform signal COM. The drive waveform signal COM is input from the fourth terminal P4, which is the output terminal of the drive control circuit 21, to the first terminal P1 which is the input terminal of the head drive circuit 262. For this input, the fourth terminal P4 and the first terminal P1 may be electrically connected to each other, and another circuit element may be provided between the two terminals. The selection signal SI is input from the sixth terminal P6, which is the output terminal of the drive control circuit 21, to the third terminal P3, which is the input terminal of the head drive circuit 262. For this input, the sixth terminal P6 and the third terminal P3 may be electrically connected to each other, and another circuit element may be provided between the two terminals. The head drive circuit 262 generates a drive signal V corresponding to the drive waveform signal COM and the selection signal SI for each discharge unit 266 and outputs the drive signal V to the piezoelectric elements 74 of the plurality of discharge units 266 in parallel. Specifically, the head drive circuit 262 outputs the drive waveform W of the drive waveform signal COM to the ejection unit 266 in which the selection signal SI indicates the ejection of ink among the plurality of ejection units 266, and selects the drive waveform W. The reference potential VM is output as the drive signal V to the ejection unit 266 in which the signal SI indicates that the ink is not ejected.

FIG. 3 is a cross-sectional view of the liquid discharge unit 264 focusing on any one discharge unit 266. In the liquid discharge section 264 shown in FIG. 3, the pressure chamber substrate 72, the diaphragm 73, the piezoelectric element 74, and the support 75 are arranged on one side of the flow path substrate 71, and the nozzle plate 76 is arranged on the other side. It is a structure. The flow path substrate 71, the pressure chamber substrate 72, and the nozzle plate 76 are formed of, for example, a silicon flat plate material, and the support 75 is formed, for example, by injection molding of a resin material. The plurality of nozzles N are formed on the nozzle plate 76. In the configuration of FIG. 3, the surface of the nozzle plate 76 facing the medium 12 constitutes the discharge surface 260 of the liquid discharge head.

An opening 712, a branch flow path 714, and a communication flow path 716 are formed in the flow path substrate 71. The branch flow path 714 and the communication flow path 716 are through holes formed for each nozzle N, and the opening 712 is a continuous opening over a plurality of nozzles N. The space in which the accommodating portion (recess) 752 formed in the support 75 and the opening 712 of the flow path substrate 71 communicate with each other is supplied from the liquid container 14 via the introduction flow path 754 of the support 75. It functions as a liquid storage chamber (reservoir) SR that stores ink.

An opening 722 is formed in the pressure chamber substrate 72 for each nozzle N. The diaphragm 73 is an elastically deformable flat plate material installed on the surface of the pressure chamber substrate 72 opposite to the flow path substrate 71. The space sandwiched between the diaphragm 73 and the flow path substrate 71 inside each opening 722 of the pressure chamber substrate 72 is a pressure chamber filled with ink supplied from the liquid storage chamber SR via the branch flow path 714. (Cavity) Functions as SC. Each pressure chamber SC communicates with the nozzle N via the communication flow path 716 of the flow path substrate 71. The space composed of the pressure chamber SC, the liquid storage chamber SR, the branch flow path 714 communicating these, the communication flow path 716, and the nozzle N constitutes the internal space of the liquid discharge head 26.

The diaphragm 73 is arranged between the pressure chamber SC and the piezoelectric element 74 to form a wall surface (upper surface) of the pressure chamber SC (internal space of the liquid discharge head 26). Specifically, a piezoelectric element 74 is formed for each nozzle N on the surface of the diaphragm 73 opposite to the pressure chamber substrate 72. Each piezoelectric element 74 is a driving element in which a piezoelectric body 744 is interposed between the first electrode 742 and the second electrode 746. The drive waveform of the drive signal V is applied to one of the first electrode 742 and the second electrode 746, and a predetermined reference potential VM is applied to the other. When the diaphragm 73 vibrates due to the deformation of the piezoelectric element 74 due to the drive waveform of the drive signal V, the pressure in the pressure chamber SC fluctuates and the ink in the pressure chamber SC is ejected from the nozzle N. Specifically, the ink of the ejection amount corresponding to the amplitude of the driving waveform of the driving signal V is ejected from the nozzle N. One discharge portion 266 exemplified in FIG. 3 is a portion including a piezoelectric element 74, a diaphragm 73, a pressure chamber SC, and a nozzle N.

Of the first electrode 742 and the second electrode 746, the electrode to which the reference potential VM is applied can be used as a common electrode across a plurality of piezoelectric elements 74. As described above, in the configuration of FIG. 3, the piezoelectric element 74 is deformed by the drive waveform of the drive signal V to fluctuate the pressure of the pressure chamber SC, so that the pressure in the internal space of the liquid discharge head 26 fluctuates, and the nozzle N Ink can be ejected from.

By the way, if a drive waveform having a resonance frequency of the diaphragm 73 is continuously applied to the piezoelectric element 74, cracks may occur in the diaphragm 73 and the piezoelectric element 74 and be damaged. Therefore, at the time of manufacture, a drive waveform is set so as not to be the resonance frequency of the diaphragm 73. However, there is a possibility that bubbles may be mixed in the pressure chamber SC, the liquid storage chamber SR, or the like during printing, and if the bubbles are mixed, the resonance frequency of the diaphragm 73 suddenly fluctuates. Therefore, the frequency of the drive waveform matches the fluctuating resonance frequency, and the vibration 73 and the piezoelectric element 74 may be cracked and damaged. If the diaphragm 73 or the piezoelectric element 74 is damaged, printing cannot be continued any more and downtime occurs.

Therefore, in the liquid discharge device 10 of the present embodiment, the operation mode is switched by the drive control circuit 21 depending on the presence or absence of air bubbles in the internal space of the liquid discharge head 26 (in the pressure chamber SC, the liquid storage chamber SR, etc.). , A different drive waveform is applied to the piezoelectric element 74. According to such a configuration, the piezoelectric element 74 can be driven with different drive waveforms depending on the presence or absence of air bubbles to vibrate the diaphragm 73. Therefore, even if the resonance frequency of the diaphragm 73 fluctuates depending on the presence or absence of bubbles, stable ink ejection can be continued regardless of the presence or absence of bubbles, and the occurrence of downtime can be suppressed. The timing of switching the operation mode may be before the start of printing or after (in the middle) of the start of printing. When switching before the start of printing, the longer the printing time, the higher the temperature of the head and the larger the bubbles tend to be. Therefore, the switching may be performed according to the length of the printing time.

FIG. 4 is a diagram for explaining the operation mode of the present embodiment. As shown in FIG. 4, the operation mode of the present embodiment includes a first mode and a second mode in which different drive waveforms W1 and W2 are applied to the piezoelectric element 74. The first mode is an operation mode in which the drive waveform W1 is applied to the piezoelectric element 74 to eject ink. The second mode is an operation mode in which a drive waveform W2 different from the drive waveform W1 is applied to the piezoelectric element 74 to eject ink. The drive waveform W1 of the first mode shown in FIG. 4 is included in the first drive waveform signal COM1, and the drive waveform W2 of the second mode is included in the second drive waveform signal COM2. The drive waveform W1 and the drive waveform W2 are generated at predetermined period T, respectively. The drive waveform W1 is applied by outputting the first drive signal V1 to the piezoelectric element 74 instructed to eject ink, and the second drive signal V2 is output to the piezoelectric element 74 instructed to eject ink. The drive waveform W2 is applied at.

In FIG. 4, the drive waveform W1 in the first mode is shown on the left side, and the drive waveform W2 in the second mode is shown on the right side. The drive waveform W1 transitions from the reference potential VM to the potential VL during the period T, and after the potential VL is held for a certain period of time, the transition from the potential VL which is the minimum value of the potential to the potential VH which is the maximum value of the potential. Then, the potential VH is held for a certain period of time. After that, the potential VH shifts to the reference potential VM. The drive waveform W2 transitions from the reference potential VM to the potential VL during the period T, and after the potential VL is held for a certain period of time, the transition from the potential VL, which is the minimum value of the potential, to VH', which is the maximum value of the potential. Then, the potential VH'is held for a certain period of time. After that, the potential VH'is changed to the reference potential VM.

According to such drive waveforms W1 and W2, the meniscus in the nozzle N is once drawn to the pressure chamber SC side by transitioning from the reference potential VM to the potential VL. After that, by transitioning from the potential VL to the potential VH or VH', the meniscus in the nozzle N moves at once toward the opening of the nozzle N (the opening of the nozzle N from which the ink is ejected), and the opening of the nozzle N is opened. Ink is pushed out from the part. Then, by transitioning from the potential VH or VH'to the reference potential VM, the meniscus in the nozzle N is drawn toward the pressure chamber SC side, and the ink extruded from the opening of the nozzle N can be torn off. The droplet is ejected from the opening of the nozzle N.

The drive waveform W1 and the drive waveform W2 are different waveforms. The drive waveform W1 and the drive waveform W2 are waveforms in which the presence or absence of resonance of the diaphragm 73 is switched depending on, for example, which of the drive waveform W1 and the drive waveform W2 is applied to the piezoelectric element 74. As described above, the resonance frequency of the vibrating plate 73 changes depending on the presence or absence of air bubbles. Therefore, for example, the drive waveform W1 is set to a waveform in which the frequency of the piezoelectric element 74 does not match the resonance frequency of the vibrating plate 73 when there are no air bubbles. W2 has a waveform in which the frequency of the piezoelectric element 74 matches the resonance frequency of the vibrating plate 73 when there is no bubble. By doing so, if the ink is ejected by the drive waveform W1 of the first mode when there is no bubble, and the ink is ejected by the drive waveform W2 of the second mode when there is an bubble, in either case. The piezoelectric element 74 can be driven with a drive waveform in which the frequency of the piezoelectric element 74 does not match the resonance frequency of the vibrating plate 73. Therefore, regardless of the presence or absence of air bubbles, the ink can be ejected with a drive waveform in which the frequency of the piezoelectric element 74 does not match the resonance frequency of the diaphragm 73, so that the occurrence of cracks in the diaphragm 73 and the piezoelectric element 74 can be suppressed.

The drive waveform W1 and the drive waveform W2 can be made different waveforms by making at least one of the waveform gradient, the maximum value of the potential, the minimum value of the potential, the amplitude of the waveform, and the frequency of the waveform different. .. The drive waveform W2 in FIG. 4 is obtained by making the maximum potential value VH'smaller than the drive waveform W1. According to the drive waveform W2, the force for pushing out the meniscus in the nozzle N is weaker than that of the drive waveform W1, so that the amount of ink ejected can be reduced as compared with the drive waveform W1. By making the maximum value of the voltage of the drive waveform W2 different in this way, it is possible to change the ejection amount of the ink to be ejected and the size of the droplet when there are bubbles. By changing the amount of ink ejected and the size of the droplets, it is possible to prevent the frequency of the piezoelectric element 74 from matching the resonance frequency of the diaphragm 73.

It is also possible to change the slope of the waveform so as not to change the amount of ink ejected or the size of the droplets. Further, if the amplitude of the drive waveform W2 is increased when the amount of bubbles is large, droplets can be ejected even if the pressure fluctuation is absorbed by the bubbles. Further, by preventing the amplitudes of the drive waveforms W1 and W2 from becoming too small, it is possible to prevent pressure fluctuations from being absorbed and forming mist. The drive waveform in which the frequency of the piezoelectric element 74 does not match the resonance frequency of the vibrating plate 73 may be a waveform in which the frequency of the piezoelectric element 74 shifts to the high frequency side, or a waveform in which the frequency shifts to the low frequency side. May be good.

A state signal VS indicating the state of the liquid discharge head 26 is output from the second terminal P2, which is the output terminal of the head drive circuit 262 shown in FIG. The state signal VS is input to the fifth terminal P5, which is an input terminal of the drive control circuit 21. For this input, the second terminal P2 and the fifth terminal P5 may be electrically connected to each other, and another circuit element may be provided between the two terminals. Since the state of the liquid discharge head 26 changes depending on whether or not there are air bubbles or the like in the internal space of the liquid discharge head 26 (in the pressure chamber SC, the liquid storage chamber SR, etc.), the state signal VS also changes. Therefore, the presence or absence of air bubbles can be determined depending on whether or not the state signal VS is a predetermined signal. For example, it can be assumed that the state signal VS with bubbles is a predetermined signal and the state signal VS without bubbles is not a predetermined signal.

The determination unit 52 shown in FIG. 2 determines whether or not there are bubbles in the pressure chamber SC by such a state signal VS. Specifically, it is determined whether the state signal VS is a signal that does not exceed the threshold value (whether it is a predetermined signal) or a signal that exceeds the threshold value (whether it is not a predetermined signal). The state signal VS is, for example, a signal including a period or amplitude of residual vibration detected by applying a predetermined drive waveform to the piezoelectric element 74. Since the cycle or amplitude of the residual vibration differs between the case where the pressure chamber SC has bubbles and the case where there are no bubbles, it can be determined whether or not there are bubbles in the pressure chamber SC by using this as the state signal VS. The threshold value of the state signal VS is calculated based on the period or amplitude of the residual vibration detected when there are bubbles, and is stored in the data table C in advance. The determination unit 52 reads the threshold value from the data table C and makes a determination. Since the cycle or amplitude of the residual vibration changes according to the amount of bubbles, the amount of bubbles can also be determined by setting a plurality of thresholds of the cycle or amplitude of the residual vibration. Further, the state signal VS is not limited to the case of the period or amplitude of the residual vibration, and any value can be used as the state signal VS as long as it is an index that can show the difference between the residual vibration with and without bubbles. good.

If the state signal VS does not exceed the threshold value, the determination unit 52 determines that there is no bubble, and if the state signal VS exceeds the threshold value, determines that there is a bubble. When the state signal VS does not exceed the threshold value (no bubbles), the first drive waveform signal COM1 in the first mode is input to the head drive circuit 262, and the head drive circuit 262 applies the drive waveform W1 to the piezoelectric element 74. Discharge the ink. On the other hand, when the state signal VS exceeds the threshold value (with bubbles), the second drive waveform signal COM2 in the second mode is input to the head drive circuit 262, and the head drive circuit 262 applies the drive waveform W2 to the piezoelectric element 74. Injects ink.

When it is determined that there are bubbles in this way, the mode is switched from the first mode to the second mode, and the drive waveform applied to the piezoelectric element 74 of the pressure chamber SC is switched from the drive waveform W1 to the drive waveform W2. Therefore, even if the resonance frequency of the diaphragm 73 fluctuates due to air bubbles, the ink can be ejected with a drive waveform so that the diaphragm 73 does not resonate, so that the occurrence of cracks in the diaphragm 73 can be effectively suppressed. Therefore, stable liquid discharge can be continued regardless of the presence or absence of air bubbles, and the occurrence of downtime can be suppressed.

Next, the driving method of the liquid discharge device 10 of the present embodiment will be described with reference to the drawings. FIG. 5 is a flowchart showing the control of the liquid discharge device 10 at the time of printing. As shown in FIG. 5, in step S11, the control unit 50 detects bubbles. Specifically, the control unit 50 causes the head drive circuit 262 to output a drive waveform signal COM including a drive waveform for bubble detection from the drive signal generation unit 40. The head drive circuit 262 drives the piezoelectric element 74 with a drive waveform for detecting bubbles, and outputs the period or amplitude of the residual vibration as a state signal VS to the determination unit 52.

In step S12, the determination unit 52 determines whether or not the state signal VS exceeds the threshold value. When the determination unit 52 determines in step S12 that the state signal VS does not exceed the threshold value, that is, when it is determined that there is no bubble, the drive control circuit 21 controls to eject ink in the first mode in step S13. I do. Specifically, the first drive waveform signal COM1 and the selection signal SI in the first mode are input to the head drive circuit 262, and the head drive circuit 262 is first driven by the piezoelectric element 74 instructed to discharge by the selection signal SI. By outputting the signal V1, the drive waveform W1 is applied to the piezoelectric element 74 to eject the ink.

Further, when the determination unit 52 determines in step S12 that the state signal VS exceeds the threshold value, that is, when it is determined that there are bubbles, the drive control circuit 21 ejects ink in the second mode in step S14. Take control. Specifically, the second drive waveform signal COM2 and the selection signal SI according to the second mode are input to the head drive circuit 262, and the head drive circuit 262 is second driven to the piezoelectric element 74 instructed to discharge by the selection signal SI. By outputting the signal V2, the drive waveform W2 is applied to the piezoelectric element 74 to eject the ink. As described above, according to the present embodiment, the piezoelectric element 74 can be driven with different drive waveforms to vibrate the diaphragm 73 depending on the presence or absence of air bubbles in the pressure chamber SC. Therefore, regardless of the presence or absence of air bubbles, the occurrence of cracks in the diaphragm 73 and the piezoelectric element 74 can be suppressed, stable ink ejection can be continued, and the occurrence of downtime can be suppressed.

<Second Embodiment>
A second embodiment of the present invention will be described. For the elements whose actions and functions are the same as those of the first embodiment in each of the embodiments exemplified below, the reference numerals used in the description of the first embodiment will be diverted and detailed description of each will be omitted as appropriate. In the first embodiment, the case where a plurality of drive waveform signals COM1 and 2 are used is exemplified, but in the second embodiment, the case where a single drive waveform signal COM including a plurality of drive waveforms is used is exemplified.

FIG. 6 is a diagram for explaining the operation mode of the second embodiment. As shown in FIG. 6, the drive waveform signal COM of the second embodiment is a drive waveform signal common to the first mode and the second mode. The period T of the drive waveform signal COM of FIG. 6 includes the drive waveform W1 and the drive waveform W2 similar to those in the first embodiment. The selection signal SI of the second embodiment includes a first selection signal SI1 for selecting the drive waveform W1 and a second selection signal SI2 for selecting the drive waveform W2. The first selection signal SI1 and the second selection signal SI2 are generated based on the print data G.

Also in the drive control circuit 21 of the second embodiment, the control as shown in FIG. 5 is performed. However, in the second embodiment, when it is determined that no air bubbles have entered the pressure chamber SC and the ink is ejected in the first mode in step S13, the first selection signal SI1 and the drive waveform signal COM in the first mode are headed. Input to the drive circuit 262. The head drive circuit 262 outputs the first drive signal V1 including the drive waveform W1 selected by the first selection signal SI1 to the piezoelectric element 74 instructed to discharge by the first selection signal SI1 to output the piezoelectric element V1. The drive waveform W1 is applied to the 74 to eject the ink.

Further, when it is determined that there are bubbles in the pressure chamber SC and the ink is ejected in the first mode in step S14, the second selection signal SI2 and the drive waveform signal COM according to the second mode are input to the head drive circuit 262. The head drive circuit 262 outputs the second drive signal V2 including the drive waveform W2 selected by the second selection signal SI2 to the piezoelectric element 74 instructed to discharge by the second selection signal SI2, thereby outputting the piezoelectric element V2. The drive waveform W2 is applied to the 74 to eject the ink.

Also in the second embodiment, as in the first embodiment, the piezoelectric element 74 can be driven with different drive waveforms to vibrate the diaphragm 73 depending on the presence or absence of air bubbles in the pressure chamber SC. Therefore, since the piezoelectric element 74 can be driven so that the diaphragm 73 does not resonate regardless of the presence or absence of air bubbles, the occurrence of cracks can be suppressed, stable ink ejection can be continued, and the occurrence of downtime can be suppressed. ..

<Third Embodiment>
A third embodiment of the present invention will be described. In the third embodiment, a case where the dot size (the size of the dots of the ink landed on the medium 12) can be changed is illustrated. FIG. 7 is a diagram for explaining the operation mode of the third embodiment. As shown in FIG. 7, in the third embodiment as well, the case where a plurality of drive waveform signals COM1 and 2 are used will be exemplified as in the first embodiment. The period T of the first drive waveform signal COM1 in FIG. 7 includes a drive waveform W11 having a dot size of “large”, a drive waveform W12 having a dot size of “medium”, and a drive waveform W13 having a dot size of “small”.

The period T of the second drive waveform signal COM2 in FIG. 7 includes a drive waveform W21 having a dot size of “large”, a drive waveform W22 having a dot size of “medium”, and a drive waveform W23 having a dot size of “small”. The drive waveform W11 having a dot size of "large" and the drive waveform W21 are different waveforms, and the drive waveform W12 having a dot size of "medium" and the drive waveform W22 are different waveforms from the drive waveform W13 having a dot size of "large". It is a waveform different from the drive waveform W23. The drive waveforms W11, W12, W13 and the drive waveforms W21, W22, and W23 are different from each other in at least one of the waveform gradient, the maximum value of the potential, the minimum value of the potential, the amplitude of the waveform, and the frequency of the waveform.

Also in the drive control circuit 21 of the third embodiment, the control as shown in FIG. 5 is performed. However, in the third embodiment, when it is determined that there are no bubbles in the pressure chamber SC and the ink is ejected in the first mode in step S13, the first drive waveform signal COM1 and the selection signal SI according to the first mode are headed. Input to the drive circuit 262. The head drive circuit 262 outputs the first drive signal V1 including any of the drive waveforms W11, W12, and W13 selected by the selection signal SI to the piezoelectric element 74 instructed to discharge by the selection signal SI. Discharge.

Further, when it is determined that there are bubbles in the pressure chamber SC and the ink is ejected in the second mode in step S14, the second drive waveform signal COM2 and the selection signal SI according to the second mode are input to the head drive circuit 262. .. The head drive circuit 262 outputs the second drive signal V2 including any of the drive waveforms W21, W22, and W23 selected by the selection signal SI to the piezoelectric element 74 instructed to discharge by the selection signal SI. Discharge.

According to the third embodiment, even if the dot size is different, the piezoelectric element 74 is driven with a different drive waveform to vibrate the diaphragm 73 depending on the presence or absence of air bubbles in the pressure chamber SC, as in the first embodiment. be able to. Therefore, since the piezoelectric element 74 can be driven so that the diaphragm 73 does not resonate regardless of the presence or absence of air bubbles, the occurrence of cracks can be suppressed, stable ink ejection can be continued, and the occurrence of downtime can be suppressed. ..

<Fourth Embodiment>
A fourth embodiment of the present invention will be described. In the third embodiment, the case where a plurality of drive waveform signals COM1 and 2 are used when the dot size can be changed is illustrated, but in the fourth embodiment, a plurality of drive waveforms are included in the case where the dot size can be changed. The case where a single drive waveform signal COM is used is illustrated. 8 and 9 are diagrams for explaining the operation mode of the fourth embodiment. FIG. 8 is an example of a drive waveform signal COM common to the first mode and the second mode. FIG. 9 illustrates a drive waveform selected in each mode according to the dot size.

The period T of the drive waveform signal COM in FIG. 8 includes the drive waveforms W11, W12, and W13 and the drive waveforms W21, W22, and W23. The shapes of the drive waveforms W11, W12, W13 and the drive waveforms W21, W22, and W23 are the same as those in FIG. 7. The period T of the drive waveform signal COM in FIG. 8 corresponds to one pixel, and one pixel is obtained from the drive waveforms W11, W12, W13 and the drive waveforms W21, W22, and W23 included in the period T. Minutes of ink are ejected. The selection signal SI of the fourth embodiment includes the first selection signal SI1 for selecting any of the drive waveforms W11, W12, and W13, and the second selection signal SI for selecting any of the drive waveforms W21, W22, and W23. The selection signal SI2 is included. The first selection signal SI1 and the second selection signal SI2 are generated based on the print data G.

Also in the drive control circuit 21 of the fourth embodiment, the control as shown in FIG. 5 is performed. However, in the fourth embodiment, when it is determined that there are no bubbles in the pressure chamber SC and the ink is ejected in the first mode in step S13, the first selection signal SI1 and the drive waveform signal COM in the first mode are head-driven. Input to circuit 262. The head drive circuit 262 outputs a first drive signal V1 including a drive waveform selected from the drive waveforms W11, W12, and W13 by the first selection signal SI1 to the piezoelectric element 74 instructed to discharge by the first selection signal SI1. By doing so, the ink is ejected. As shown in the first mode of FIG. 9, the drive waveform W11 is selected by the first selection signal SI1 at the dot size “large”, the drive waveform W12 is selected at the dot size “medium”, and the drive waveform W12 is selected at the dot size “small”. The drive waveform W13 is selected.

Further, when it is determined that there are bubbles in the pressure chamber SC and the ink is ejected in the first mode in step S14, the second selection signal SI2 and the drive waveform signal COM according to the second mode are input to the head drive circuit 262. The head drive circuit 262 outputs a second drive signal V2 including a drive waveform selected from the drive waveforms W21, W22, and W23 by the second selection signal SI2 to the piezoelectric element 74 instructed to discharge by the second selection signal SI2. By doing so, the ink is ejected. As shown in the second mode of FIG. 9, the drive waveform W21 is selected by the second selection signal SI2 at the dot size “large”, the drive waveform W22 is selected at the dot size “medium”, and the drive waveform W22 is selected at the dot size “small”. The drive waveform W23 is selected.

According to the fourth embodiment, as in the third embodiment, even if the dot size is different, the piezoelectric element 74 is driven with a different drive waveform depending on the presence or absence of air bubbles in the pressure chamber SC to vibrate the diaphragm 73. be able to. Therefore, since the piezoelectric element 74 can be driven so that the diaphragm 73 does not resonate regardless of the presence or absence of air bubbles, the occurrence of cracks can be suppressed, stable ink ejection can be continued, and the occurrence of downtime can be suppressed. ..

<Fifth Embodiment>
A fifth embodiment of the present invention will be described. In the first to fourth embodiments, a case where different drive waveforms are applied to the piezoelectric element 74 depending on the presence or absence of air bubbles in the pressure chamber SC is illustrated, but in the fifth embodiment, the pressure is applied. An example is an example in which a different drive waveform is applied to the piezoelectric element 74 according to the amount of air bubbles in the chamber SC. The amount of bubbles here indicates the amount and size of bubbles in the pressure chamber SC. However, when there are no bubbles in the pressure chamber SC, the amount of bubbles is set to zero “0”, so that the fifth embodiment is applied not only when there are bubbles but also when there are no bubbles.

10 and 11 are diagrams for explaining the operation mode of the fifth embodiment. FIG. 10 is an example of a drive waveform signal COM common to the first mode and the second mode, and has the same drive waveforms as the drive waveforms W11, W12, and W13 of FIG. FIG. 11 illustrates a drive waveform selected in each mode according to the dot size.

In the fifth embodiment, the piezoelectric element 74 is driven so that the diaphragm 73 does not resonate by limiting the drive waveform that can be selected according to the amount of air bubbles in the pressure chamber SC. Specifically, the drive waveform of the dot size that can be selected is limited according to the amount of bubbles. For example, as shown in FIG. 11, it is divided into a first mode (selection signal SI11) when the amount of bubbles is zero (without bubbles) and a second mode when the amount of bubbles is not zero (with bubbles). Further, in the second mode, it is divided into a selection signal SI21 when the bubble amount is "small", a selection signal SI22 when the bubble amount is "medium", and a selection signal SI23 when the bubble amount is "large". The amount of bubbles is not limited to "small", "medium", and "large", and may be divided into two, "small" and "large", or may be divided into four or more.

In the first mode of FIG. 11, the drive waveform W11 having a dot size of "large", the drive waveform W12 having a dot size of "medium", and the drive waveform W13 having a dot size of "small" can be selected as in the case of the fourth embodiment. And. On the other hand, when the bubble amount is "small" in the second mode of FIG. 11, the drive waveform W11 having a dot size "large" and the drive waveform W13 having a dot size "small" can be selected, and the dot size is "medium". The drive waveform W12 of is limited to "-" which cannot be selected. When the bubble amount is "medium", the drive waveform W12 with a dot size "medium" and the drive waveform W13 with a dot size "small" can be selected, and the drive waveform W11 with a dot size "large" cannot be selected. do. When the amount of bubbles is "small", the drive waveform W11 with a dot size of "large" can be selected, and the drive waveform W12 with a dot size of "medium" and the drive waveform W13 with a dot size of "small" cannot be selected. do.

Also in the drive control circuit 21 of the fifth embodiment, the control as shown in FIG. 5 is performed. However, in the fifth embodiment, in step S11, the bubble amount is detected and the bubble amount is determined by the state signal VS. Specifically, when a plurality of threshold values, for example, a first threshold value, a second threshold value, and a third threshold value are provided in the case of the state signal VS, the bubble amount is set to zero when the state signal VS does not exceed the first threshold value. (No air bubbles) can be set. Further, when the first threshold value is exceeded but the second threshold value is not exceeded, the bubble amount is set to "small", and when the second threshold value is exceeded but the third threshold value is not exceeded, the bubble amount is set to "medium" and exceeds the third threshold value. The case can be set to "many" bubbles.

If the state signal VS does not exceed the first threshold value in step S12, it is determined that there is no bubble amount in the pressure chamber SC, and in step S13, the drive control circuit 21 controls to eject ink in the first mode. .. Specifically, the first selection signal SI11 by the first mode and the drive waveform signal COM are input to the head drive circuit 262. The head drive circuit 262 includes a first drive waveform selected from the drive waveforms W11, W12, and W13 by the first selection signal SI11 according to the dot size in the piezoelectric element 74 instructed to discharge by the first selection signal SI11. Ink is ejected by outputting the drive signal V1.

When the state signal VS exceeds the first threshold value in step S12, the determination unit 52 determines that the pressure chamber SC has an amount of air bubbles, and in step S14, the drive control circuit 21 ejects ink in the second mode. Control to do. In this case, the second selection signal SI21, SI22, or SI23 and the drive waveform signal COM are head-driven according to the amount of air bubbles in the pressure chamber SC determined as described above. It is input to the circuit 262. The head drive circuit 262 is a second drive including a drive waveform selected from the drive waveforms W21, W22, and W23 according to the amount of bubbles with respect to the piezoelectric element 74 instructed to be discharged by the input second selection signal SI2. Ink is ejected by outputting the signal V2. For example, when the amount of bubbles is "small" in the second mode, the drive waveform W12 with a dot size of "medium" cannot be selected. Therefore, in the pixel with a dot size of "medium", for example, instead of the drive waveform W12, the dot size is "large". Ink is ejected by the drive waveform W11 of the above and the drive waveform W13 of the dot size "small".

As described above, in the fifth embodiment, the piezoelectric element 74 can be driven so that the diaphragm 73 does not resonate by limiting the drive waveform to be used according to the amount of bubbles in the pressure chamber SC. Therefore, since the piezoelectric element 74 can be driven so that the diaphragm 73 does not resonate regardless of the amount of bubbles, the occurrence of cracks can be suppressed, stable ink ejection can be continued, and the occurrence of downtime can be suppressed. In the fifth embodiment, the case where the selectable drive waveform is limited according to the amount of bubbles in the pressure chamber SC has been illustrated, but the present invention is not limited to this, and the resolution is changed according to the amount of bubbles in the pressure chamber SC. You may do it. For example, in FIG. 11, in the portion where the drive waveform is not selectable “−”, the drive waveform may be selectable and the resolution may be increased. As the resolution changes, the number of pixels and the period T of the drive waveform signal COM change. Therefore, the piezoelectric element 74 can be driven so that the diaphragm 73 does not resonate by changing the resolution according to the amount of bubbles.

In each of the above embodiments, the case where ink is ejected with different drive waveforms according to the state signal VS (presence or absence of bubbles and amount of bubbles) is illustrated, but the mode that can be selected by the user is further limited. It is also good. For example, the operation mode selection button displayed on the display unit 62 can be changed according to the status signal VS from the second terminal P2 shown in FIG. Examples of such an operation mode include a high-quality mode and a high-speed mode, a mode with complementary printing and a mode without complementary printing. For example, when the state signal VS is a predetermined signal (without bubbles), one mode is displayed, and when the state signal is not a predetermined signal (with bubbles), the other mode is displayed. Since the drive waveform used differs depending on the operation mode, it is possible to prevent the diaphragm from resonating even if the resonance frequency of the diaphragm 73 fluctuates.

Further, different drive waveforms may be applied to the piezoelectric element 74 according to the continuous application time of the drive waveform to the piezoelectric element 74. As the continuous application time of the drive waveform becomes longer, the temperature of the liquid discharge head 26 rises, and the resonance frequency of the diaphragm 73 also fluctuates due to the increase in bubbles in the pressure chamber SC of the liquid discharge head 26. Therefore, by allowing different drive waveforms to be applied to the piezoelectric element 74 according to the continuous application time of the drive waveform to the piezoelectric element 74, vibration occurs even if the resonance frequency of the vibrating plate 73 fluctuates due to a temperature rise. The generation of cracks due to the resonance of the plate 73 can be suppressed. The continuous application time of the drive waveform is not only when the ink is ejected from the nozzle N, but also when the drive waveform for slight vibration is applied without ejecting the ink from the nozzle N. Since the temperature rises, the time for applying such a drive waveform may be added to the continuous application time. Further, when the amount of ink discharged is large, such as the flushing operation of the liquid ejection head 26 performed as the maintenance process of the nozzle N, the ink in the pressure chamber SC is easily replaced with new ink at a low temperature, so that the liquid is liquid. The rise in temperature of the discharge head 26 is alleviated. Therefore, the time for applying the drive waveform in such a case may be subtracted from the continuous application time of the drive waveform.

In the liquid discharge device 10 of the above embodiment, the maximum width capable of serial printing while moving the liquid discharge head 26 in the X direction is 24 inches or more and 75 inches or less, and the width capable of serial printing is 24 inches. , 36 inch, 44 inch, 64 inch medium 12 is supported. According to such a configuration, when the maximum width capable of serial printing is 24 inches or more and 75 inches or less, the generation of cracks due to the resonance of the diaphragm 73 can be effectively suppressed. Further, since the maximum width capable of serial printing is 24 inches or more and 75 inches or less, the total length of the signal line through which the drive signal or the like propagates can be about 1 m to 3 m, so that the maximum width capable of serial printing is increased. Compared with the case of 75 inches or more, the impedance and inductance of the signal line can be reduced. Therefore, it is possible to suppress the occurrence of failure or malfunction due to overshoot or undershoot of the drive signal or the like. The maximum width at which serial printing is possible and the size of the medium 12 are not limited to the above cases.

Further, the liquid ejection head 26 of the above embodiment ejects ink with a drive waveform having a frequency of 30 kHz or higher. In this way, printing can be performed at high speed by ejecting ink with a drive waveform having a high frequency of 30 kHz or more, so that the diaphragm 73 does not resonate even when the resonance frequency of the diaphragm 73 occurs at 30 kHz or higher. Can be. Therefore, even in the case of high-speed printing in which the frequency of the drive waveform is 30 kHz or more, stable ink ejection can be continued regardless of the presence or absence of bubbles, and the occurrence of downtime can be suppressed. The frequency of the drive waveform is not limited to the above case.

Further, the drive waveform of the first mode and the drive waveform of the second mode of the above embodiment can be freely stored in the data table C (storage device 203). The operation method of the liquid discharge device 10 for storing the drive waveform is a first step of storing the drive waveform of the first mode in the data table C and a second step of storing the drive waveform of the second mode in the data table C. And have. According to this, the drive waveform of the first mode and the drive waveform of the second mode can be freely stored in the data table C, which is convenient. Further, in the first mode and the second mode, the ink can be ejected by the drive waveform stored in the data table C, so that it is possible to print according to the user's preference while suppressing the occurrence of downtime. Become.

<Modification example>
The embodiments and embodiments exemplified above can be variously modified. Specific modes of modification are illustrated below. Two or more embodiments arbitrarily selected from the following examples and the above embodiments can be appropriately merged to the extent that they do not contradict each other.

(1) In the above-described embodiment, the case where the determination unit 52 determines the presence / absence of bubbles or the amount of bubbles in the pressure chamber SC has been exemplified, but the present invention is not limited to this, and the inside of the liquid ejection head 26 filled with ink is not limited to this. The presence or absence of air bubbles or the amount of air bubbles in the space, for example, the liquid storage chamber SR may be determined. For example, by providing the piezoelectric element 74 on the support 75 or the like on which the liquid storage chamber SR is formed and setting the cycle or amplitude of the residual vibration of the piezoelectric element 74 as the state signal VS, the presence or absence of air bubbles in the liquid storage chamber SR or The amount of air bubbles can be determined.

The resonance frequency of the diaphragm 73 also fluctuates depending on the presence or absence of bubbles in the liquid storage chamber SR or the amount of bubbles. Therefore, by ejecting ink by changing the drive waveform according to the presence or absence of bubbles or the amount of bubbles in the liquid storage chamber SR, stable liquid ejection can be continued regardless of the presence or absence of bubbles, and the liquid is down. The generation of time can be suppressed.

The position of the bubble can also be determined by the period or amplitude of the residual vibration between the piezoelectric element 74 of the liquid storage chamber SR and the piezoelectric element 74 of the pressure chamber SC. Therefore, it is possible to apply different drive waveforms to the piezoelectric element 74 according to the position of the bubble. For example, when there are bubbles in the liquid storage chamber SR, it is possible to determine which of the plurality of pressure chambers SCs is closer to the pressure chamber SC. The resonance frequency of the diaphragm 73 is more likely to fluctuate as the piezoelectric element 74 of the pressure chamber SC closer to the position where the air bubbles are in the liquid storage chamber SR. Therefore, it is also possible to drive the piezoelectric element 74 of the close pressure chamber SC in the second mode. According to such a configuration, even if the resonance frequency of the diaphragm 73 changes depending on the position of the bubble, the generation of cracks due to the resonance of the diaphragm 73 can be suppressed.

(2) In the above-described embodiment, in the liquid discharge head 26, a state signal for determining whether or not there are bubbles in the internal space filled with ink (in the pressure chamber SC, in the liquid storage chamber SR, etc.). The case where residual vibration is used as VS is illustrated, but the present invention is not limited to this. For example, in the liquid ejection head 26, the presence or absence of bubbles and the amount of bubbles can be determined by a sensor that detects the liquid level of the bubble chamber provided in the ink flow path. Further, when the ink is circulated in the liquid ejection head 26, the presence or absence of bubbles and the amount of bubbles can be estimated from the circulation flow velocity and the non-circulation time.

(3) In the above-described embodiment, the serial head in which the carriage 18 on which the liquid discharge head 26 is mounted is repeatedly reciprocated along the X direction is exemplified, but the line head in which the liquid discharge heads 26 are arranged over the entire width of the medium 12 is illustrated. The present invention can also be applied to the above.

(4) In the above-described embodiment, the piezoelectric liquid discharge head 26 using a piezoelectric element that applies mechanical vibration to the pressure chamber is exemplified, but a heat generating element that generates air bubbles inside the pressure chamber by heating is illustrated. It is also possible to adopt the thermal type liquid discharge head used.

(5) The liquid discharge device 10 exemplified in the above-described embodiment can be adopted in various devices such as a facsimile machine and a copier, in addition to a device dedicated to printing. However, the application of the liquid ejection device 10 of the present invention is not limited to printing. For example, a liquid discharge device that discharges a solution of a coloring material is used as a manufacturing device for forming a color filter of a liquid crystal display device, an organic EL (Electroluminescence) display, an FED (field emission display), and the like. Further, a liquid discharge device that discharges a solution of a conductive material is used as a manufacturing device for forming wiring and electrodes on a wiring substrate. It is also used as a chip manufacturing device that discharges a solution of a bio-organic substance as a kind of liquid.

10 ... liquid discharge device, 12 ... medium, 14 ... liquid container, 18 ... carriage, 20 ... control unit, 202 ... control device, 203 ... storage device, 21 ... drive control circuit, 22 ... transfer mechanism, 24 ... carriage, 26. ... Liquid discharge head, 260 ... Discharge surface, 262 ... Head drive circuit, 264 ... Liquid discharge unit, 266 ... Discharge unit, 40 ... Drive signal generation unit, 50 ... Control unit, 52 ... Judgment unit, 60 ... Operation panel, 62 ... Display unit, 71 ... Flow path board, 712 ... Opening, 714 ... Branch flow path, 716 ... Communication flow path, 72 ... Pressure chamber board, 722 ... Opening, 73 ... Vibration plate, 74 ... Piezoelectric element, 742 ... 1st electrode, 744 ... piezoelectric body, 746 ... second electrode, 75 ... support, 754 ... introduction flow path, 76 ... nozzle plate, C ... data table, COM ... drive waveform signal, COM1 ... first drive waveform signal, COM2 ... 2nd drive waveform signal, G ... print data, N ... nozzle, P1 ... 1st terminal, P2 ... 2nd terminal, P3 ... 3rd terminal, SC ... pressure chamber, SI ... selection signal, SI1, SI11 ... 1 selection signal, SI2, SI21, SI22, SI23 ... 2nd selection signal, SR ... liquid storage chamber, T ... period, V ... drive signal, V1 ... 1st drive signal, V2 ... 2nd drive signal, VL, VH, VH'... potential, VM ... reference potential, VS ... state signal, W drive waveform, W1, W11, W12, W13 ... drive waveform, W2, W21, W22, W23 ... drive waveform.

Claims (17)

A drive control circuit for a liquid discharge device including a liquid discharge head that discharges the liquid by varying the pressure in the internal space filled with the liquid by a drive element.
The liquid discharge head has a first terminal into which a drive waveform signal having a drive waveform for driving the drive element is input, and a second terminal in which a state signal indicating the state of the liquid discharge head is output. Equipped with a head drive circuit that has
The drive waveform signal includes a first drive waveform signal and a second drive waveform signal having different drive waveforms.
The drive control circuit is
When the state signal from the second terminal is a predetermined signal, the first drive waveform signal is input to the first terminal.
When the state signal from the second terminal is not the predetermined signal, the second drive waveform signal is input to the first terminal.
The liquid discharge head includes a drive element, a pressure chamber, a diaphragm arranged between the pressure chamber and the drive element to form a wall surface of the internal space, and vibrated by the drive element.
The different drive waveform is a drive control circuit in which the presence or absence of resonance of the diaphragm is switched.
A drive control circuit for a liquid discharge device including a liquid discharge head that discharges the liquid by varying the pressure in the internal space filled with the liquid by a drive element.
The liquid discharge head has a first terminal for inputting a drive waveform signal having a plurality of drive waveforms for driving the drive element, and a second terminal for outputting a state signal indicating the state of the liquid discharge head. A head drive circuit comprising, and comprising a head drive circuit for outputting a drive signal having a drive waveform selected from the drive waveform signal to the drive element.
The drive signal includes a first drive signal and a second drive signal having different drive waveforms.
The drive control circuit is
When the state signal from the second terminal is a predetermined signal, the first drive signal is input to the drive element.
When the state signal from the second terminal is not the predetermined signal, the second drive signal is input to the drive element.
The liquid discharge head includes a drive element, a pressure chamber, a diaphragm arranged between the pressure chamber and the drive element to form a wall surface of the internal space, and vibrated by the drive element.
The different drive waveform is a drive control circuit in which the presence or absence of resonance of the diaphragm is switched.
A drive control circuit for a liquid discharge device including a liquid discharge head that discharges the liquid by varying the pressure in the internal space filled with the liquid by a drive element.
The liquid discharge head has a first terminal for inputting a drive waveform signal having a plurality of drive waveforms for driving the drive element, and a second terminal for outputting a state signal indicating the state of the liquid discharge head. A head drive circuit comprising a third terminal into which a selection signal for selecting a drive waveform applied to the drive element from the drive waveform signal is input.
The selection signal includes a first selection signal and a second selection signal for selecting different drive waveforms.
The drive control circuit is
When the state signal from the second terminal is a predetermined signal, the first selection signal is input to the third terminal.
When the state signal from the second terminal is not the predetermined signal, the second selection signal is input to the third terminal.
The liquid discharge head includes a drive element, a pressure chamber, a diaphragm arranged between the pressure chamber and the drive element to form a wall surface of the internal space, and vibrated by the drive element.
The different drive waveform is a drive control circuit in which the presence or absence of resonance of the diaphragm is switched.
A drive control circuit for a liquid discharge device including a liquid discharge head that discharges the liquid by varying the pressure in the internal space filled with the liquid by a drive element.
The liquid discharge head has a first terminal into which a drive waveform signal having a drive waveform for driving the drive element is input, and a second terminal in which a state signal indicating the state of the liquid discharge head is output. Equipped with a head drive circuit that has
The drive waveform signal includes a first drive waveform signal and a second drive waveform signal having different drive waveforms.
The drive control circuit is
When the state signal from the second terminal is a predetermined signal, the first drive waveform signal is input to the first terminal.
When the state signal from the second terminal is not the predetermined signal, the second drive waveform signal is input to the first terminal.
The liquid discharge device includes a display unit that displays an operation mode of the liquid discharge device.
A drive control circuit that changes the operation mode displayed on the display unit according to the status signal.
A drive control circuit for a liquid discharge device including a liquid discharge head that discharges the liquid by varying the pressure in the internal space filled with the liquid by a drive element.
The liquid discharge head has a first terminal for inputting a drive waveform signal having a plurality of drive waveforms for driving the drive element, and a second terminal for outputting a state signal indicating the state of the liquid discharge head. A head drive circuit comprising, and comprising a head drive circuit for outputting a drive signal having a drive waveform selected from the drive waveform signal to the drive element.
The drive signal includes a first drive signal and a second drive signal having different drive waveforms.
The drive control circuit is
When the state signal from the second terminal is a predetermined signal, the first drive signal is input to the drive element.
When the state signal from the second terminal is not the predetermined signal, the second drive signal is input to the drive element.
The liquid discharge device includes a display unit that displays an operation mode of the liquid discharge device.
A drive control circuit that changes the operation mode displayed on the display unit according to the status signal.
A drive control circuit for a liquid discharge device including a liquid discharge head that discharges the liquid by varying the pressure in the internal space filled with the liquid by a drive element.
The liquid discharge head has a first terminal for inputting a drive waveform signal having a plurality of drive waveforms for driving the drive element, and a second terminal for outputting a state signal indicating the state of the liquid discharge head. A head drive circuit comprising a third terminal into which a selection signal for selecting a drive waveform applied to the drive element from the drive waveform signal is input.
The selection signal includes a first selection signal and a second selection signal for selecting different drive waveforms.
The drive control circuit is
When the state signal from the second terminal is a predetermined signal, the first selection signal is input to the third terminal.
When the state signal from the second terminal is not the predetermined signal, the second selection signal is input to the third terminal.
The liquid discharge device includes a display unit that displays an operation mode of the liquid discharge device.
A drive control circuit that changes the operation mode displayed on the display unit according to the status signal.
A drive control circuit for a liquid discharge device including a liquid discharge head that discharges the liquid by varying the pressure in the internal space filled with the liquid by a drive element.
The liquid discharge head has a first terminal into which a drive waveform signal having a drive waveform for driving the drive element is input, and a second terminal in which a state signal indicating the state of the liquid discharge head is output. Equipped with a head drive circuit that has
The drive waveform signal includes a first drive waveform signal and a second drive waveform signal having different drive waveforms.
The drive control circuit is
When the state signal from the second terminal is a predetermined signal, the first drive waveform signal is input to the first terminal.
When the state signal from the second terminal is not the predetermined signal, the second drive waveform signal is input to the first terminal.
The different drive waveform is applied to the drive element according to the continuous application time of the drive waveform to the drive element.
A drive control circuit that causes the different drive waveforms to be applied to the drive element according to the position of bubbles contained in the internal space of the liquid discharge head.
A drive control circuit for a liquid discharge device including a liquid discharge head that discharges the liquid by varying the pressure in the internal space filled with the liquid by a drive element.
The liquid discharge head has a first terminal for inputting a drive waveform signal having a plurality of drive waveforms for driving the drive element, and a second terminal for outputting a state signal indicating the state of the liquid discharge head. A head drive circuit comprising, and comprising a head drive circuit for outputting a drive signal having a drive waveform selected from the drive waveform signal to the drive element.
The drive signal includes a first drive signal and a second drive signal having different drive waveforms.
The drive control circuit is
When the state signal from the second terminal is a predetermined signal, the first drive signal is input to the drive element.
When the state signal from the second terminal is not the predetermined signal, the second drive signal is input to the drive element.
The different drive waveform is applied to the drive element according to the continuous application time of the drive waveform to the drive element.
A drive control circuit that causes the different drive waveforms to be applied to the drive element according to the position of bubbles contained in the internal space of the liquid discharge head.
A drive control circuit for a liquid discharge device including a liquid discharge head that discharges the liquid by varying the pressure in the internal space filled with the liquid by a drive element.
The liquid discharge head has a first terminal for inputting a drive waveform signal having a plurality of drive waveforms for driving the drive element, and a second terminal for outputting a state signal indicating the state of the liquid discharge head. A head drive circuit comprising a third terminal into which a selection signal for selecting a drive waveform applied to the drive element from the drive waveform signal is input.
The selection signal includes a first selection signal and a second selection signal for selecting different drive waveforms.
The drive control circuit is
When the state signal from the second terminal is a predetermined signal, the first selection signal is input to the third terminal.
When the state signal from the second terminal is not the predetermined signal, the second selection signal is input to the third terminal.
The different drive waveform is applied to the drive element according to the continuous application time of the drive waveform to the drive element.
A drive control circuit that causes the different drive waveforms to be applied to the drive element according to the position of bubbles contained in the internal space of the liquid discharge head.
The different drive waveform is a waveform of a voltage signal, and any of claims 1 to 9 , wherein at least one of the gradient of the waveform, the maximum value of the potential, the minimum value of the potential, the amplitude of the waveform, and the frequency of the waveform is different. Drive control circuit described in.
The drive control circuit according to any one of claims 1 to 10 , wherein a different drive waveform is applied to the drive element according to the amount of air bubbles in the internal space of the liquid discharge head.
The drive control circuit according to any one of claims 1 to 11 , wherein the liquid discharge device is capable of serial printing and has a large size of 24 inches or more and 75 inches or less.
The drive control circuit according to claim 12 , wherein the liquid discharge device corresponds to any medium of 24 inches, 36 inches, 44 inches, and 64 inches as a width capable of serial printing.
The drive control circuit according to claim 1, wherein the liquid discharge head discharges the liquid with a drive waveform having a frequency of 30 kHz or higher.
A liquid discharge head that discharges the liquid by varying the pressure in the internal space filled with the liquid by the driving element,
A drive control circuit that applies a drive waveform to the drive element is provided.
The drive control circuit is
The drive waveform applied to the drive element is switched according to the continuous application time of the drive waveform to the drive element.
The drive waveform applied to the drive element is switched according to the position of the air bubbles contained in the internal space of the liquid discharge head.
A liquid discharge device that switches the drive waveform applied to the drive element according to the amount of air bubbles in the internal space of the liquid discharge head.
A liquid discharge head that discharges the liquid by varying the pressure in the internal space filled with the liquid by a driving element.
The drive waveform applied to the drive element is switched according to the continuous application time of the drive waveform to the drive element.
The drive waveform applied to the drive element is switched according to the position of the air bubbles contained in the internal space of the liquid discharge head.
A liquid discharge head that switches the drive waveform applied to the drive element according to the amount of air bubbles in the internal space of the liquid discharge head.
It is a method of driving a liquid discharge device.
The liquid discharge device is
A liquid discharge head that discharges the liquid by varying the pressure in the internal space filled with the liquid by the driving element,
A drive control circuit that applies a drive waveform to the drive element is provided.
The drive control circuit is
The drive waveform applied to the drive element is switched according to the continuous application time of the drive waveform to the drive element.
The drive waveform applied to the drive element is switched according to the position of the air bubbles contained in the internal space of the liquid discharge head.
A driving method for switching the driving waveform applied to the driving element according to the amount of air bubbles in the internal space of the liquid discharge head.

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