Printing apparatus, printing method, and computer program

Abstract

The present invention provides a printing apparatus that can suppress variations in the state of the discharged liquid, such as the amount and speed of the discharged liquid, regardless of environmental factors or the characteristics of the liquid discharge configuration. [Solution] The printing apparatus includes a nozzle that discharges liquid from a pressure chamber using an energy-transferring element, a control unit that generates a first drive waveform for driving the energy-transferring element and includes a discharge waveform for discharging liquid from the nozzle, and a detection circuit that detects the residual pressure wave when the energy-transferring element is driven based on the first drive waveform and a residual pressure wave is generated in the pressure chamber. The control unit receives the detection result from the detection circuit, and the control unit generates a second drive waveform that includes a corrected discharge waveform obtained by correcting the discharge waveform based on the detection result from the detection circuit.

Description

[Technical Field]

[0001] This technology relates to a printing apparatus, a printing method, and a computer program that eject liquid from a nozzle. [Background technology]

[0002] An inkjet recording device is disclosed, comprising a nozzle for discharging liquid, a pressure chamber communicating with the nozzle, and a piezoelectric actuator that applies pressure fluctuations to the ink in the pressure chamber. The inkjet recording device generates non-discharge vibration pulses that apply pressure fluctuations to the ink in the pressure chamber to prevent ink from being discharged from the nozzle. For example, depending on the ink temperature, the piezoelectric actuator can be driven with non-discharge vibration pulses to agitate the ink in the pressure chamber and suppress temperature variations in the pressure chamber (see Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-44166 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Incidentally, the waveform of the discharge pulse used to eject liquid may vary depending on environmental factors such as temperature or humidity, or on the characteristics of the liquid-discharging components such as the nozzle and pressure chamber. Therefore, for example, the amount and speed of the discharged liquid may vary.

[0005] This disclosure is made in view of the above circumstances and aims to provide a printing apparatus, a printing method, and a computer program that can suppress variations in the state of the discharged liquid, such as the amount and speed of the discharged liquid, regardless of environmental factors or the characteristics of the liquid discharge configuration. [Means for solving the problem]

[0006] A printing apparatus according to one embodiment of the present disclosure includes a nozzle that discharges liquid in a pressure chamber using an energy-giving element, a control unit that generates a first drive waveform for driving the energy-giving element, which includes a discharge waveform for discharging liquid from the nozzle, and a detection circuit that detects a residual pressure wave when the energy-giving element is driven based on the first drive waveform and a residual pressure wave is generated in the pressure chamber, wherein the detection result of the detection circuit is input to the control unit, and the control unit generates a second drive waveform which includes a corrected discharge waveform obtained by correcting the discharge waveform based on the detection result of the detection circuit.

[0007] A printing method according to one embodiment of the present disclosure is a printing method in which a liquid in a pressure chamber is discharged from a nozzle by an energy-giving element, wherein a first drive waveform is generated which includes a discharge waveform for discharging the liquid from the nozzle and for driving the energy-giving element, and when a residual pressure wave is generated in the pressure chamber as the energy-giving element is driven based on the first drive waveform, the residual pressure wave is detected, and a second drive waveform is generated which includes a corrected discharge waveform obtained by correcting the discharge waveform based on the detection result.

[0008] A computer program according to one embodiment of the present disclosure controls a printing apparatus that discharges liquid from a nozzle in a pressure chamber using an energy-giving element. The computer program controls the printing apparatus by generating a first drive waveform which includes a discharge waveform for discharging liquid from the nozzle and for driving the energy-giving element. When a residual pressure wave is generated in the pressure chamber as the energy-giving element is driven based on the first drive waveform, the computer program controls the residual pressure wave and, based on the detection result, causes the computer program to generate a second drive waveform which includes a corrected discharge waveform obtained by correcting the discharge waveform. [Effects of the Invention]

[0009] In a printing apparatus, a printing method, and a computer program according to an embodiment of the present disclosure, a residual pressure wave is detected after driving an energy applying element with a first driving waveform. The residual pressure wave reflects environmental factors or characteristics of a configuration that discharges a liquid. Based on the detected residual pressure wave, the first driving waveform is corrected to generate a second driving waveform, so that variations in the state of the discharged liquid can be suppressed.

Brief Description of the Drawings

[0010] [Figure 1] It is a plan view schematically showing a printing apparatus. [Figure 2] It is a schematic partial enlarged cross-sectional view of an inkjet head. [Figure 3] It is a block diagram of a control device. [Figure 4] It is a conceptual diagram showing a driving waveform. [Figure 5] It is a circuit diagram schematically showing a configuration of an amplifier. [Figure 6] It is a block diagram schematically showing a configuration of a control circuit and a memory. [Figure 7] It is a graph schematically showing a discharge waveform. [Figure 8] It is a graph schematically showing a residual pressure wave. [Figure 9] It is a graph schematically showing a residual pressure wave and a pressure wave after identification. [Figure 10] It is a graph schematically showing a pressure wave and a target pressure wave. [Figure 11] It is a graph schematically showing a corrected discharge waveform. [Figure 12] It is a graph schematically showing a corrected driving waveform.

Embodiments for Carrying Out the Invention

[0011] The present invention will be described below based on drawings showing a printing apparatus according to an embodiment. Figure 1 is a schematic plan view of the printing apparatus. In the following description, the terms front, back, left, and right shown in Figure 1 will be used. The front-back direction corresponds to the transport direction, and the left-right direction corresponds to the scanning direction. Also, the front side of Figure 1 corresponds to the top side, and the back side corresponds to the bottom side, and the terms up and down will also be used.

[0012] As shown in Figure 1, the printing apparatus 1 comprises a platen 2, an ink ejection device 3, transport rollers 4, 5, etc. Recording paper 200, which is a recording medium, is placed on the upper surface of the platen 2. The ink ejection device 3 ejects ink onto the recording paper 200 placed on the platen 2 to record an image. The ink ejection device 3 comprises a carriage 6, a sub-tank 7, four inkjet heads 8, a circulation pump (not shown), etc.

[0013] Two guide rails 11 and 12, extending to the left and right, are provided on the upper side of the platen 2 to guide the carriage 6. An endless belt 13, extending to the left and right, is connected to the carriage 6. The endless belt 13 is driven by a carriage drive motor 14. Driven by the endless belt 13, the carriage 6 is guided by the guide rails 11 and 12 and moves back and forth in the scanning direction in the area facing the platen 2. More specifically, with the carriage 6 supporting four inkjet heads 8, it performs a first movement in the scanning direction, moving the heads from one position to another, from left to right, and a second movement in the scanning direction, moving from right to left. Then, a second movement is performed, moving the head from another position to a certain position to the left.

[0014] A cap 20 and a flushing receiver 21 are provided between guide rails 11 and 12. The cap 20 and the flushing receiver 21 are positioned below the ink ejection device 3. The cap 20 is located at the right end of the guide rails 11 and 12, and the flushing receiver 21 is located at the left end of the guide rails 11 and 12. Note that the cap 20 and the flushing receiver 21 may be positioned in reverse.

[0015] The sub-tank 7 and the four inkjet heads 8 are mounted on a carriage 6 and move back and forth in the scanning direction together with the carriage 6. The sub-tank 7 is connected to a cartridge holder 15 via a tube 17. One or more ink cartridges 16 (four colors in this embodiment) are installed in the cartridge holder 15. Examples of the four colors include black, yellow, cyan, and magenta.

[0016] Inside the sub-tank 7, four ink chambers (not shown) are formed. Each of the four ink chambers stores one of the four colors of ink supplied from the four ink cartridges 16.

[0017] The four inkjet heads 8 are arranged in the scanning direction below the sub-tank 7. Multiple nozzles 80 (see Figure 2) are formed on the underside of each inkjet head 8. Each inkjet head 8 corresponds to one color of ink and is connected to one ink chamber. In other words, the four inkjet heads 8 each correspond to one of the four colors of ink and are connected to one of the four ink chambers.

[0018] The inkjet head 8 is provided with an ink supply port and an ink discharge port. The ink supply port and ink discharge port are connected to the ink chamber via tubes or the like. A circulation pump is interposed between the ink supply port and the ink chamber.

[0019] Ink is pumped out of the ink chamber by a circulation pump, flows through the ink supply port to the inkjet head 8, and is ejected from the nozzle 80. Ink that is not ejected from the nozzle 80 returns to the ink chamber through the ink outlet. The ink circulates between the ink chamber and the inkjet head 8. The four inkjet heads 8 move in the scanning direction together with the carriage 6, ejecting the four colors of ink supplied from the sub-tank 7 onto the recording paper 200.

[0020] As shown in Figure 1, the transport roller 4 is positioned upstream (rear) of the platen 2 in the transport direction. The transport roller 5 is positioned downstream (front) of the platen 2 in the transport direction. The two transport rollers 4 and 5 are driven synchronously by a motor (not shown). The two transport rollers 4 and 5 transport the recording paper 200 placed on the platen 2 in a transport direction perpendicular to the scanning direction. The printing device 1 is equipped with a control device 50. The control device 50 includes a control circuit 51 (see Figure 3) having a CPU or logic circuit (e.g., FPGA or ASIC), a main memory, an auxiliary memory (not shown), etc.

[0021] The control circuit 51 executes multiple processes, such as various arithmetic and control processes. These multiple processes may be executed by a single processor or logic circuit within the control circuit 51, or they may be distributed among multiple processors or logic circuits within the control circuit 51. A separate processor or logic circuit may be used to execute one process and another. The main memory is, for example, a memory 55 such as non-volatile memory and RAM. Examples of auxiliary storage devices include ROM and rewritable storage media such as EEPROM, flash ROM, and hard disks. A control program is stored in the auxiliary storage device. The control circuit 51 reads the control program from the auxiliary storage device into the main memory and executes it. The control program may be installed in the auxiliary storage device from a recording medium 70, such as an optical disc or portable flash memory. The control circuit 51 may also download the control program to the auxiliary storage device from an external device 100 via a network. The processing performed by the control program, such as printing and flashing, may be implemented by distributed processing between the control circuit 51 and the external device 100 or terminals (not shown).

[0022] The control device 50 receives print jobs and drive waveform data from the external device 100, and the memory 55 stores the received print jobs and drive waveform data. Based on the print job, the control device 50 controls the drive of the ink ejector 3 and transport rollers 4, etc., and executes the printing process.

[0023] Figure 2 is an enlarged cross-sectional view of a schematic portion of the inkjet head 8. The inkjet head 8 comprises a plurality of pressure chambers 81. A diaphragm 82 is formed on the upper side of the pressure chambers 81. A layered piezoelectric body 83 is formed on the upper side of the diaphragm 82. The piezoelectric body 83 comprises an upper piezoelectric body 83a and a lower piezoelectric body 83b. A first common electrode 84 is formed on the upper side of each pressure chamber 81, between the piezoelectric body 83 and the diaphragm 82.

[0024] A second common electrode 86 is provided inside the piezoelectric element 83, specifically between the upper piezoelectric element 83a and the lower piezoelectric element 83b. The second common electrode 86 is positioned above each pressure chamber 81 and above the first common electrode 84. The second common electrode 86 is positioned so as not to face the first common electrode 84. Individual electrodes 85 are formed on the upper surface of the piezoelectric element 83, above each pressure chamber 81. The individual electrodes 85, the first common electrode 84, and the second common electrode 86 face each other vertically across the piezoelectric element 83. The diaphragm 82, piezoelectric element 83, first common electrode 84, individual electrodes 85, and second common electrode 86 constitute an actuator 88. The actuator 88 constitutes an energy-transferring element.

[0025] A nozzle plate 87 is provided at the bottom of each pressure chamber 81. Multiple nozzles 80 are formed on the nozzle plate 87, penetrating vertically. Each nozzle 80 is located on the lower side of each pressure chamber 81.

[0026] The first common electrode 84 is connected to the COM terminal, which in this embodiment is connected to ground, and the second common electrode 86 is connected to the VCOM terminal. The VCOM voltage is higher than the COM voltage. The individual electrodes 85 are connected to the switching driver 54 (see Figure 3). When a High or Low voltage is applied to the individual electrodes 85, the piezoelectric element 83 deforms and the diaphragm 82 vibrates. The vibration of the diaphragm 82 causes ink (liquid) to be ejected from the pressure chamber 81 through the nozzle 80.

[0027] The individual electrodes 85 correspond to the first electrode, the second common electrode 86 corresponds to the second electrode, and the first common electrode 84 corresponds to the third electrode. The diaphragm 82 corresponds to the third piezoelectric layer. In other words, the actuator 88 has a three-layer structure.

[0028] Figure 3 is a block diagram of the control device 50, and Figure 4 is a conceptual diagram showing the drive waveform Pw. The control device 50 includes a control circuit 51, a D / A converter 52, an amplifier 53, a switching driver 54, a memory 55, a detection circuit 56, and an A / D converter 57. The memory 55 stores drive waveform data. The drive waveform data is data that shows the voltage waveform applied to the individual electrodes 85, i.e., the drive waveform that drives the actuator 88, and is quantized data. The drive waveform shown in the drive waveform data corresponds to the first drive waveform. The control circuit 51, D / A converter 52, amplifier 53, and memory 55 correspond to the control unit.

[0029] The D / A converter 52 converts a digital signal into an analog signal. The amplifier 53 is an amplification circuit that amplifies the analog signal. In this embodiment, the amplifier 53 is a self-excited Class D amplifier. Alternatively, a separately excited Class D amplifier may be used instead of the self-excited Class D amplifier. The switching driver 54 comprises a plurality of nth switches 54(n) (n=1, 2, ...). The nth switch 54(n) is composed of, for example, an analog switch IC. One end of each of the plurality of nth switches 54(n) is connected to the amplifier 53 via a common bus. The other end of each nth switch 54(n) is connected to each individual electrode 85 corresponding to a plurality of nozzles 80. In other words, one nth switch 54(n) is provided for each actuator 88.

[0030] The switching driver 54 is equipped with a plurality of detection switches 54a(n) (n=1, 2, ...). Each detection switch 54a(n) is composed of, for example, an analog switch IC. One end of each detection switch 54a(n) is connected to the detection circuit 56 via a common bus. The other end of each detection switch 54a is connected to each individual electrode 85 corresponding to one of the plurality of nozzles 80. In other words, one detection switch 54a(n) is provided for each actuator 88.

[0031] The first capacitor 89a is composed of individual electrodes 85, a first common electrode 84, and a piezoelectric element 83. The second capacitor 89b is composed of individual electrodes 85, a second common electrode 86, and a piezoelectric element 83.

[0032] The control circuit 51 outputs a switch control signal S1 to the switching driver 54 that controls the opening and closing of multiple nth switches 54(n) and multiple detection switches 54a(n). When the control circuit 51 drives the actuator 88 corresponding to the nth switch 54(n), it outputs a switch control signal S1 to close the nth switch 54(n) and outputs drive waveform data to the D / A converter 52. The nth switch 54(n) is closed, that is, the actuator 88 and the amplifier 53 are connected. The drive waveform data is converted into an analog signal by the D / A converter 52, that is, into a drive waveform Pw. The drive waveform Pw is amplified by the amplifier 53 and input to the actuator 88 corresponding to the nth switch 54(n). The actuator 88 is driven based on the drive waveform Pw, and ink is ejected from the nozzle 80. The state in which the nth switch 54(n) is closed corresponds to the first connection state.

[0033] As shown in Figure 4, the drive waveform Pw includes an ejection waveform Pd0 for ejecting ink from the nozzle 80 and a cancellation waveform Pc for attenuating the residual pressure wave W1 based on the ejection waveform Pd0. The residual pressure wave W1 is a pressure wave that propagates through the pressure chamber 81 even after ink (liquid) has been ejected from the pressure chamber 81 via the nozzle 80 by a main pressure wave generated from the actuator 88 by the drive of the actuator 88 and propagated through the pressure chamber 81. In other words, it is a pressure wave that remains in the pressure chamber 81. The cancellation waveform Pc is generated after the ejection waveform Pd0 is generated. The ejection waveform Pd0 is different from the cancellation waveform Pc. That is, the amplitude or frequency of the ejection waveform Pd0 is different from that of the cancellation waveform Pc, and the shape of the ejection waveform Pd0 is different from that of the cancellation waveform Pc. The cancellation waveform Pc plays a role in weakening the vibration of the residual pressure wave W1. The cancellation waveform Pc weakens the residual pressure wave W1 remaining in the pressure chamber 81, suppressing the attenuation or amplification of the main pressure wave based on the discharge waveform Pd0 for the next discharge.

[0034] When detecting a residual pressure wave W1 (see Figure 8) generated in the pressure chamber 81 after the actuator 88 corresponding to the nth switch 54(n) is driven, the control circuit 51 outputs a switch control signal S1 to close the detection switch 54a(n). The detection switch 54a(n) is closed, that is, the actuator 88 and the detection circuit 56 are connected. At this time, the other detection switches 54a(1) to 54a(n-1) are opened. The detection circuit 56 detects the residual pressure wave W1 (see Figure 7) generated in the pressure chamber 81 after the actuator 88 is driven. The detected residual pressure wave W1 is an analog signal. The detection circuit 56 outputs the residual pressure wave W1 to the A / D converter 57. The A / D converter 57 converts the analog signal residual pressure wave W1 into a digital signal and outputs it to the control circuit 51. The state in which the detection switch 54a(n) is closed corresponds to the second connection state.

[0035] Multiple detection circuits 56 corresponding to each detection switch 54a(1) to 54a(n) may be provided. In this case, multiple detection switches 54a(1) to 54a(n) can be closed to simultaneously detect the residual pressure wave W1.

[0036] Figure 5 is a schematic circuit diagram showing the configuration of amplifier 53. Amplifier 53 is a self-oscillating digital amplifier. Amplifier 53 comprises a comparator 53a, a level shifter 53m, a gate driver circuit 53b, an NMOS circuit 53c, a low-pass filter 53e, and negative feedback wiring 53h.

[0037] Comparator 53a is connected to the positive power supply VDD1 and the negative power supply VSS1. In other words, comparator 53a is connected to both the positive power supply VDD1 and the negative power supply VSS1, so it has a dual power supply configuration. NMOS circuit 53c is connected to the positive power supply VDD2 and the negative power supply VSS2. Level shifter 53m has, for example, a Zener diode and changes the level of the signal input from comparator 53a to compensate for the difference in reference voltages between the negative power supply VSS1 and the negative power supply VSS2.

[0038] The positive input terminal of comparator 53a is connected to D / A converter 52, and the analog signal from D / A converter 52 is input to the positive input terminal of comparator 53a. The output terminal of comparator 53a is connected to gate driver circuit 53b via level shifter 53m, and the output signal of comparator 53a is modified in level by level shifter 53m and input to gate driver circuit 53b. Gate driver circuit 53b is connected to NMOS circuit 53c, and outputs an on or off signal to NMOS circuit 53c based on the output signal from comparator 53a. NMOS circuit 53c is driven by the on or off signal from gate driver circuit 53b and outputs a signal to low-pass filter (LPF) 53e.

[0039] The low-pass filter 53e comprises an inductor 53f and a capacitor 53g. One end of the inductor 53f is connected to an NMOS circuit 53c, and the other end is connected to one end of the capacitor 53g. The other end of the capacitor 53g is connected to ground. The other end of the inductor 53f and one end of the capacitor 53g are connected to the switching driver 54. That is, the low-pass filter 53e outputs a signal, i.e., an amplified analog signal, i.e., a drive waveform, to the switching driver 54. One end of the negative feedback wiring 53h is connected to the other end of the inductor 53f and one end of the capacitor 53g, and the other end of the negative feedback wiring 53h is connected to the negative input terminal of the comparator 53a.

[0040] Figure 6 is a block diagram illustrating the configuration of the control circuit 51 and memory 55, Figure 7 is a graph illustrating the discharge waveform Pd0, Figure 8 is a graph illustrating the residual pressure wave W1, and Figure 9 is a graph illustrating the residual pressure wave W1 and the identified pressure wave W2. As shown in Figure 6, the control circuit 51 includes a model identification unit 51a, a target pressure wave setting unit 51b, a corrected discharge waveform generation unit 51c, a pressure wave calculation unit 51d, a corrected discharge waveform extraction unit 51e, a calculation unit 51f, and a corrected drive waveform generation unit 51g.

[0041] As shown in FIG. 7, when the actuator 88 is driven by the ejection waveform Pd0, as shown in FIG. 8, a residual pressure wave W1 is generated in the pressure chamber 81. The residual pressure wave causes the diaphragm 82 and the piezoelectric body 83 to vibrate, generating a voltage waveform. That is, the residual pressure wave is expressed as a voltage waveform. The pressure wave is also expressed as a voltage waveform. The pressure wave calculation unit 51d has a storage unit, and this storage unit stores a model. The initial model is stored in advance in the storage unit of the pressure wave calculation unit 51d. The model is a transfer function showing the relationship between the ejection waveform and the pressure wave. That is, when the residual pressure wave W1 is input to the model identification unit 51a, the model identification unit 51a identifies predetermined parameters of the transfer function. Then, the model identification unit 51a outputs the predetermined parameters to the corrected ejection waveform generation unit 51c. When an ejection waveform is input to the pressure wave calculation unit 51d, the pressure wave calculation unit 51d calculates and outputs a pressure wave including the residual pressure wave based on the model and the ejection waveform. The pressure wave output by the pressure wave calculation unit 51d includes the residual pressure wave and the main pressure wave, which is a pressure wave generated from the actuator 88 when the actuator 88 is driven by the ejection waveform and transmitted through the pressure chamber 81.

[0042] In the present embodiment, the transfer function G of the model is a second-order lag system and includes the transfer function G0 of the fundamental wave and the transfer functions G(m) (m = 1, 2, ···) of a plurality of harmonics. The transfer function G is represented by the following equations 1 and 2. Equation 1: G = G0 + G(m) Equation 2: G(m) = G(1) + G(2) + ···

[0043] The transfer function G0 is represented by the following equation 3, and the transfer function Gm is represented by the following equation 4. Equation 3: G0 = ((K0·ω0) / (s 2 + 2ζ0ω0s + ω0 2 ))·e -L0s Equation 4: G(m) = ((K m ·ω m ) / (s 2 + 2ζ m ω m s + ω m 2 ))·e -Lms K0, K m ω0 and ω0 indicate the gain. m ζ0, ζ m The θ indicates the attenuation rate, and L0 and Lm indicate the dead time length.

[0044] The residual pressure wave detected by the detection circuit 56 is output from the A / D converter 57 to the model identification unit 51a. The information regarding the residual pressure wave input to the model identification unit 51a via the A / D converter 57 is a digital signal. For example, as shown in Figure 9, when a residual pressure wave W1 is input, the model identification unit 51a identifies the model so as to output a pressure wave W2 that includes a residual pressure wave W2a corresponding to the residual pressure wave W1. Specifically, gains K0, K m , resonant frequency ω0, ω m , damping rate ζ0, ζ m The model identification unit 51a identifies the model by adjusting parameters such as those mentioned above. In other words, if there are multiple candidates for pressure wave W2 that include a residual pressure wave identical or similar to the residual pressure wave W1, the model identification unit 51a narrows it down to one. That is, if there are multiple candidates for pressure wave W2 based on the residual pressure wave W1, the model identification unit 51a determines one. The parameters are then stored in the memory 55. The pressure wave W2 includes the residual pressure wave W2a and the main pressure wave W2b, which is a pressure wave generated from the actuator 88 by the discharge waveform driving the actuator 88 and propagating within the pressure chamber 81. The transfer function G of the model is not limited to a second-order lag system, but may also be a first-order lag system or a multi-order lag system of third order or higher.

[0045] Figure 10 is a graph illustrating the pressure wave W2 and the target pressure wave W3. After the model identification unit 51a identifies the model and the pressure wave W2, it sends the corrected discharge waveform generation unit 51c the identified gains K0 and K m , resonant frequency ω0, ω m , damping rate ζ0, ζ mThe system outputs parameters such as the target pressure wave setting unit 51b outputs the target pressure wave W3 to the calculation unit 51f. The calculation unit 51f receives the output of the pressure wave calculation unit 51d, i.e., the output of the model. The calculation unit 51f calculates the difference between the target pressure wave W3 and the output of the model and outputs it to the corrected discharge waveform generation unit 51c. Based on the input difference, the corrected discharge waveform generation unit 51c generates a discharge waveform, i.e., a corrected discharge waveform Pd1 which is a corrected discharge waveform, and outputs it to the pressure wave calculation unit 51d. The pressure wave calculation unit 51d outputs a pressure wave in response to the input of the corrected discharge waveform Pd1. The output of the pressure wave calculation unit 51d is fed back and output to the calculation unit 51f. The corrected discharge waveform generation unit 51c repeats the generation of the corrected discharge waveform Pd1 and output to the pressure wave calculation unit 51d until the difference between the target pressure wave W3 calculated by the calculation unit 51f and the output of the pressure wave calculation unit 51d becomes less than or equal to a predetermined value.

[0046] The corrected discharge waveform generation unit 51c generates a corrected discharge waveform Pd1 using the parameters and the target pressure wave W3. The corrected discharge waveform extraction unit 51e extracts the corrected discharge waveform Pd1 generated by the corrected discharge waveform generation unit 51c and outputs the extracted corrected discharge waveform Pd1 to the memory 55. The memory 55 stores the corrected discharge waveform Pd1.

[0047] The target pressure wave setting unit 51b adjusts the parameters, for example, so that the amplitude of the residual pressure wave of the target pressure wave W3 is smaller than that of the residual pressure wave W2a. This reduces the influence of the residual pressure wave on the state of the ink in the pressure chamber 81.

[0048] The corrected ejection waveform generation unit 51c generates a corrected ejection waveform Pd1 by correcting the target pressure wave W3 based on the difference so that, for example, the amplitude of the main pressure wave of the target pressure wave W3 is equal to the amplitude of the main pressure wave W2b of the pressure wave W2. If the amplitude of the main pressure wave W2b is smaller than the amplitude of the main pressure wave to be realized by the ejection waveform Pd0, the amplitude of the main pressure wave W2b of the pressure wave W2 is increased so that it is equal to the amplitude of the main pressure wave of the target pressure wave W3, thereby enabling ink to be ejected from the nozzle 80 in the desired amount and speed. On the other hand, if the amplitude of the main pressure wave W2b is larger than the amplitude of the main pressure wave to be realized by the ejection waveform Pd0, the amplitude of the main pressure wave W2b of the pressure wave W2 is decreased so that it is equal to the amplitude of the main pressure wave of the target pressure wave W3, thereby enabling ink to be ejected from the nozzle 80 in the desired amount and speed.

[0049] Figure 11 is a graph illustrating the corrected output waveform Pd1. The corrected output waveform extraction unit 51e extracts the corrected output waveform Pd1 generated by the corrected output waveform generation unit 51c and outputs the extracted corrected output waveform Pd1 to the memory 55. The memory 55 stores the corrected output waveform Pd1. The amplitude, frequency, and shape of the corrected output waveform Pd1 are different from those of the output waveform Pd0.

[0050] Figure 12 is a graph illustrating the corrected drive waveform Pw1. As shown in Figure 12, the corrected drive waveform generation unit 51g adds a cancellation waveform Pc1 to the corrected output waveform Pd1 stored in memory 55 to generate the corrected drive waveform Pw1. The corrected drive waveform Pw1 is stored in memory 55. The corrected drive waveform Pw1 corresponds to the second drive waveform.

[0051] The control circuit 51 performs a process to generate the corrected ejection waveform Pd1 and the corrected drive waveform Pw1 described above, for example, by performing a flushing process when the printing device is started or before the printing process is executed. The flushing process is a process in which the carriage 6 is moved to the upper side of the flushing receiver 21 and ink is ejected from the nozzle 80 to prevent clogging of the nozzle 80, for example, and is a process in which no printing is done on the recording paper 200. When the printing process is executed, the control circuit 51 drives the actuator 88 using the corrected drive waveform Pw1. As a result, variations in parameters such as the amplitude, frequency, and shape of the pressure wave in the pressure chamber 81 are suppressed, and variations in the state of the ink ejected from the nozzle 80, such as the amount of ink ejected and the ejection speed, can be suppressed. The corrected drive waveform generation unit 51g may make the corrected ejection waveform Pd1 the corrected drive waveform Pw1 without adding a cancellation waveform Pc1 to the corrected ejection waveform Pd1. For example, if the residual pressure wave generated in the pressure chamber 81 by driving the corrected discharge waveform Pd1 is small, there is little need to add a cancellation waveform Pc1 to the corrected discharge waveform Pd1.

[0052] The pressure wave output by the pressure wave calculation unit 51d includes, but is not limited to, a residual pressure wave and a main pressure wave, which is generated from the actuator 88 when the actuator 88 is driven by the discharge waveform and propagates within the pressure chamber 81. The pressure wave output by the pressure wave calculation unit 51d may not include a residual pressure wave and may only include the main pressure wave, which is generated from the actuator 88 when the actuator 88 is driven by the discharge waveform and propagates within the pressure chamber 81.

[0053] The corrected discharge waveform generation unit 51c repeatedly generates the corrected discharge waveform Pd1 and outputs it to the pressure wave calculation unit 51d until the difference between the target pressure wave W3 calculated by the calculation unit 51f and the output of the pressure wave calculation unit 51d falls below a predetermined value, but is not limited to this. The corrected discharge waveform generation unit 51c may stop repeatedly generating the corrected discharge waveform Pd1 and outputting it to the pressure wave calculation unit 51d after repeating the process for a predetermined number of times. Alternatively, the corrected discharge waveform Pd1 may be evaluated, and if the evaluation value exceeds a predetermined value, the repeated generation of the corrected discharge waveform Pd1 and outputting it to the pressure wave calculation unit 51d may be stopped.

[0054] Computer programs (program products) can be deployed to run on a single computer, located in one site, or distributed across multiple sites and interconnected by a communication network.

[0055] The embodiments disclosed herein should be considered illustrative and not restrictive in all respects. The scope of the present invention is intended to include all modifications within the claims and equivalents thereof. The matters described in each embodiment can be combined with one another. Furthermore, the independent and dependent claims described in the claims can be combined with one another in any combination, regardless of the form of reference. In addition, the claims use a multi-claim format in which claims refer to two or more other claims (multi-claim format), but are not limited thereto. They may also be described using a multi-claim format in which at least one multi-claim refers to another multi-claim (multi-multi-claim format). [Explanation of Symbols]

[0056] 1 Printing device 50 Control device 51 Control circuit (control unit) 51a Model Identification Unit 51b Target pressure wave setting section 51c Correction discharge waveform generation section 51e Correction discharge waveform extraction section 52 D / A Converter (Control Unit) 53 Amplifier (control unit) 54 Switching Drivers 55 Memory (Control Unit) 56 Detection Circuit 57 A / D Converter 80 nozzles 81 Pressure Chamber 88 Actuator

Claims

1. A nozzle that discharges liquid from a pressure chamber using an energy-transferring element, A control unit that generates a first drive waveform for driving the energy-transferring element, which includes a discharge waveform for discharging liquid from the nozzle, When the energy-generating element is driven based on the first drive waveform, and a residual pressure wave is generated in the pressure chamber, a detection circuit for detecting the residual pressure wave is provided. Equipped with, The control unit receives the detection result from the detection circuit. The control unit generates a second drive waveform, which includes a corrected discharge waveform obtained by correcting the discharge waveform, based on the detection result of the detection circuit. Printing device.

2. The amplitude or frequency of the corrected discharge waveform is different from the discharge waveform. The printing apparatus according to claim 1.

3. A storage unit that stores a model showing the relationship between the discharge waveform and the residual pressure wave, A switch that switches between a first connection state connecting the energy-granting element and the control unit, and a second connection state connecting the energy-granting element and the detection circuit. Equipped with, The control unit, After the detection circuit detects the residual pressure wave by switching from the first connection state to the second connection state, Identify the model to output the residual pressure wave, A target pressure wave to be generated in the pressure chamber is set, The second drive waveform, including the corrected discharge waveform, is generated based on the target pressure wave and the model. The printing apparatus according to claim 1 or 2.

4. The aforementioned model is a second-order lag system model. The control unit corrects the target pressure wave based on the gain, attenuation rate, and resonant frequency of the model. The printing apparatus according to claim 3.

5. The control unit corrects the target pressure wave based on the gain, attenuation rate, and resonant frequency of the fundamental wave of the model, and the gain, attenuation rate, and resonant frequency of the harmonics of the model. The printing apparatus according to claim 4.

6. The control unit, The output of the aforementioned model is fed back, After feeding back the output of the model, the corrected discharge waveform is generated based on the difference between the output of the model and the target pressure wave. The printing apparatus according to claim 3.

7. The first drive waveform includes a cancellation waveform for attenuating the residual pressure wave. The discharge waveform is different from the cancellation waveform. The printing apparatus according to claim 1 or 2.

8. In a printing method in which a liquid in a pressure chamber is ejected from a nozzle by an energy-transferring element, A discharge waveform for discharging liquid from the nozzle is included, and a first drive waveform for driving the energy supply element is generated. When the energy-generating element is driven based on the first drive waveform, and a residual pressure wave is generated in the pressure chamber, the residual pressure wave is detected. Based on the detection results, a second drive waveform is generated, which includes a corrected discharge waveform obtained by correcting the discharge waveform. Printing method.

9. In a computer program that controls a printing device that ejects liquid from a nozzle in a pressure chamber using an energy-transferring element, The aforementioned printing apparatus, A discharge waveform for discharging liquid from the nozzle is included, and a first drive waveform for driving the energy supply element is generated. When the energy-generating element is driven based on the first drive waveform, and a residual pressure wave is generated in the pressure chamber, the residual pressure wave is detected. Based on the detection results, a second drive waveform is generated, which includes a corrected discharge waveform obtained by correcting the discharge waveform. A computer program that executes a process.

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