Printing apparatus, printing method, and computer program

Abstract

To provide a printer capable of suppressing insufficient deformation of a nozzle, a printing method, and a computer program.SOLUTION: A printing apparatus includes a nozzle that ejects a liquid by an energy application element, a first conversion unit that converts a first drive waveform for driving the energy application element into a first PWM signal by a triangular wave, a second conversion unit that converts a second drive waveform for driving the energy application element into a second PWM signal by a triangular wave, a multiplexing unit that generates a multiplexed signal based on a plurality of PWM signals including the first PWM signal and the second PWM signal, and a demodulator that demodulates any one of the drive waveforms from a plurality of drive waveforms including the first drive waveform and the second drive waveform based on the multiplexed signal.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present technology relates to a printing apparatus, a printing method, and a computer program that performs printing by ejecting liquid from nozzles. [Background technology]

[0002] A printing device has been proposed that generates a time division multiplexed signal from a plurality of drive waveforms that drive nozzles, samples the time division multiplexed signal, and generates a drive waveform corresponding to each nozzle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-155438 Summary of the Invention [Problem to be solved by the invention]

[0004] The reproducibility of the drive waveform improves by increasing the sampling frequency. However, the time during which the drive waveform voltage is applied to the nozzle (piezoelectric layer) at each sampling point also becomes shorter. This can result in insufficient nozzle deformation.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a printing device, a printing method, and a computer program that can suppress insufficient deformation of nozzles. [Means for solving the problem]

[0006] A printing device according to one embodiment of the present disclosure includes a nozzle that ejects liquid using an energy imparting element, a first conversion unit that converts a first drive waveform for driving the energy imparting element into a first PWM signal using a triangular wave, a second conversion unit that converts a second drive waveform for driving the energy imparting element into a second PWM signal using a triangular wave, a multiplexing unit that generates a multiplexed signal based on a plurality of PWM signals including the first PWM signal and the second PWM signal, and a demodulator that demodulates one of the drive waveforms from a plurality of drive waveforms including the first drive waveform and the second drive waveform based on the multiplexed signal.

[0007] A printing method according to one embodiment of the present disclosure is a printing method for printing by ejecting liquid from a nozzle using an energy imparting element, the printing method comprising: converting a first drive waveform for driving the energy imparting element into a first PWM signal using a triangular wave; converting a second drive waveform for driving the energy imparting element into a second PWM signal using a triangular wave; multiplexing a plurality of signals based on a plurality of PWM signals including a first signal based on the first PWM signal and a second signal based on the second PWM signal to generate a multiplexed signal; and demodulating one of the drive waveforms from a plurality of drive waveforms including the first drive waveform and the second drive waveform based on the multiplexed signal.

[0008] A computer program according to one embodiment of the present disclosure is a computer program executable on a printing device having nozzles that eject liquid using energy imparting elements, and causes the printing device to convert a first drive waveform for driving the energy imparting elements into a first PWM signal using a triangular wave, convert a second drive waveform for driving the energy imparting elements into a second PWM signal using a triangular wave, multiplex multiple signals based on multiple PWM signals including a first signal based on the first PWM signal and a second signal based on the second PWM signal, generate a multiplexed signal, and demodulate one of the drive waveforms from a plurality of drive waveforms including the first drive waveform and the second drive waveform based on the multiplexed signal. [Effects of the Invention]

[0009] In the printing apparatus, printing method, and computer program according to an embodiment of the present disclosure, the use of a triangular wave and a PWM signal can suppress insufficient deformation of the nozzles. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a plan view schematically showing a printing device according to a first embodiment. [Figure 2] FIG. 2 is a simplified, partially enlarged cross-sectional view of the inkjet head. [Figure 3] FIG. 2 is a block diagram showing a control device and an actuator. [Figure 4] 3A to 3C are explanatory diagrams illustrating examples of a first drive waveform, a second drive waveform, and a third drive waveform. [Figure 5] 10 is an explanatory diagram illustrating conversion of a drive waveform using a triangular wave into a PWM signal by a control device, and demodulation of the PWM signal into a drive waveform. FIG. [Figure 6] FIG. 10 is an explanatory diagram illustrating a state in which absolute values ​​of differential values ​​whose levels have been adjusted by each level shifter are combined. [Figure 7] FIG. 10 is a block diagram showing a control device and an actuator according to a second embodiment. [Figure 8] FIG. 10 is an explanatory diagram illustrating a state in which absolute values ​​of differential values ​​whose widths have been adjusted by the width adjusters are combined. [Figure 9] FIG. 10 is a block diagram showing a control device and an actuator according to a third embodiment. [Figure 10] FIG. 10 is a block diagram showing an inkjet head and a control device according to a first modified example. [Figure 11] FIG. 10 is a block diagram showing an inkjet head, a main body substrate, and a relay substrate according to a second modified example. [Figure 12] FIG. 11 is a block diagram showing an inkjet head, a main body substrate, and a relay substrate according to a third modified example. [Figure 13] FIG. 10 is a block diagram showing an inkjet head and a main body substrate according to a fourth modified example. [Figure 14]FIG. 11 is a block diagram showing an inkjet head and a relay substrate according to a fifth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Embodiment 1) The present invention will be described below with reference to the drawings showing a printing device according to a first embodiment. FIG. 1 is a plan view showing a simplified view of the printing device. In the following description, the front, back, left, and right directions shown in FIG. 1 will be used. The front and back directions correspond to the transport direction, and the left and right directions correspond to the scanning direction. The front side of FIG. 1 corresponds to the top, and the back side corresponds to the bottom, and the terms up and down will also be used.

[0012] As shown in Fig. 1, the printing device 1 includes a platen 2, an ink ejection device 3, and transport rollers 4 and 5. A recording medium, i.e., a recording sheet 200, is placed on the upper surface of the platen 2. The ink ejection device 3 ejects ink onto the recording sheet 200 placed on the platen 2 to record an image. The ink ejection device 3 includes a carriage 6, a sub-tank 7, four inkjet heads 8, a circulation pump 10, and the like.

[0013] Two guide rails 11 and 12 extending laterally are provided above the platen 2 to guide the carriage 6. An endless belt 13 extending laterally is connected to the carriage 6. The endless belt 13 is driven by a carriage drive motor 14. As the endless belt 13 is driven, the carriage 6 is guided by the guide rails 11 and 12 and moves back and forth in the scanning direction in an area facing the platen 2. More specifically, the carriage 6, while supporting four inkjet heads 8, performs a first movement in which the heads are moved from one position to another from left to right in the scanning direction, and a second movement in which the heads are moved from another position to one position from right to left in the scanning direction.

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

[0015] The sub-tank 7 and 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. Ink cartridges 16 of one or more colors (four colors in this embodiment) are attached to the cartridge holder 15. The four colors include, for example, black, yellow, cyan, and magenta.

[0016] Four ink chambers (not shown) are formed inside the subtank 7. The four ink chambers store inks of four colors supplied from the four ink cartridges 16, respectively.

[0017] The four inkjet heads 8 are aligned in the scanning direction below the subtank 7. A plurality of nozzles 80 (see FIG. 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. That is, the four inkjet heads 8 correspond to four colors of ink, respectively, and are connected to four ink chambers, respectively.

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

[0019] Ink sent from the ink chamber by the circulation pump flows into the inkjet head 8 through the ink supply port and is ejected from the nozzles 80. Ink that is not ejected from the nozzles 80 returns to the ink chamber through the ink outlet port. The ink circulates between the ink chamber and the inkjet head 8. The four inkjet heads 8 eject the four colors of ink supplied from the subtanks 7 onto the recording paper 200 while moving together with the carriage 6 in the scanning direction.

[0020] As shown in FIG. 1, the transport roller 4 is disposed upstream (rearward) of the platen 2 in the transport direction. The transport roller 5 is disposed downstream (frontward) 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 includes a control device 50. The control device 50 includes a controller 50a (see FIG. 3). The controller 50a includes a control unit (see FIG. 3) such as a CPU or a logic circuit (e.g., FPGA), a main memory unit, and an auxiliary memory unit. The main memory unit includes, for example, RAM. The auxiliary memory unit includes a rewritable storage device such as an EEPROM, a flash ROM, or a hard disk. The auxiliary memory unit stores a control program. The controller 50a reads the control program from the auxiliary memory unit into the main memory unit and executes it. The controller 50a stores data generated by the execution of the control program in the auxiliary memory unit. The control program may be stored in a storage medium 60, such as an optical disk, flash memory, or hard disk, and may be downloaded from the storage medium 60 to the auxiliary storage unit. Alternatively, the control program may be downloaded from an external server via a network to the auxiliary storage unit. Processing by the control program, such as printing processing, multiplexing processing, and demodulation processing described below, may be performed by a server or terminal connected to the controller 50a via a network, or may be performed by distributed processing between a server and a device other than the server (e.g., a terminal). The controller 50a receives a print job from the external device 100 and stores it in the auxiliary storage unit. Based on the print job, the controller 50a controls the driving of the ink ejection device 3, the transport rollers 4, etc., and executes the print processing.

[0021] 2 is a simplified, partially enlarged cross-sectional view of the inkjet head 8. The inkjet head 8 includes a plurality of pressure chambers 81. The plurality of pressure chambers 81 form a plurality of pressure chamber rows. A vibration plate 82 is formed above the pressure chambers 81. A layered piezoelectric body 83 is formed above the vibration plate 82. A first common electrode 84 is formed above each pressure chamber 81, between the piezoelectric body 83 and the vibration plate 82.

[0022] A second common electrode 86 is provided inside the piezoelectric body 83. The second common electrode 86 is arranged above each pressure chamber 81 and above the first common electrode 84. The second common electrode 86 is arranged in a position that does not face the first common electrode 84. An individual electrode 85 is formed above each pressure chamber 81 on the upper surface of the piezoelectric body 83. The individual electrode 85 faces the first common electrode 84 and the second common electrode 86 above and below, with the piezoelectric body 83 sandwiched between them. The vibration plate 82, the piezoelectric body 83, the first common electrode 84, the individual electrode 85 and the second common electrode 86 constitute an actuator 88.

[0023] A nozzle plate 87 is provided below each pressure chamber 81. A plurality of nozzles 80 are formed in the nozzle plate 87, penetrating vertically. Each nozzle 80 is disposed below each pressure chamber 81. The plurality of nozzles 80 form a plurality of nozzle rows extending along the rows of pressure chambers.

[0024] The first common electrode 84 is connected to a COM terminal, which in this embodiment is ground, and the second common electrode 86 is connected to a VCOM terminal. The VCOM voltage is higher than the COM voltage. When a high or low voltage is applied to the individual electrode 85, the piezoelectric body 83 deforms and the diaphragm 82 vibrates. The vibration of the diaphragm 82 causes ink to be ejected from the pressure chamber 81 via the nozzle 80.

[0025] 3 is a block diagram showing the control device 50 and the actuator 88. The control device 50 includes a controller 50a, a first drive waveform generator 51, a second drive waveform generator 52, and a third drive waveform generator 53. The control device 50 includes a comparator 51a corresponding to the first drive waveform generator 51, a differentiator 51b, an absolute value calculator 51c, and a level shifter 51d.

[0026] The control device 50 includes a comparator 52a, a differentiator 52b, an absolute value calculator 52c, and a level shifter 52d corresponding to the second drive waveform generator 52. The control device 50 includes a comparator 53a, a differentiator 53b, an absolute value calculator 53c, and a level shifter 53d corresponding to the third drive waveform generator 53.

[0027] The control device 50 includes a plurality of selectors 55(n) and a plurality of demodulators 56(n) (n=1, 2, ...) corresponding to a plurality of actuators 88. One selector 55(n) corresponds to one actuator 88, and one demodulator 56(n) corresponds to one actuator 88. The control device 50 includes a triangular wave generator 57. The triangular wave generator 57 generates a triangular wave and outputs the generated triangular wave to each of the comparators 51a to 53a and each of the demodulators 56(n).

[0028] 4 is an explanatory diagram illustrating an example of a first drive waveform A, a second drive waveform B, and a third drive waveform C. The first to third drive waveforms A, B, and C are waveforms that deform the piezoelectric element 83, vibrate the vibration plate 82, and eject ink in the pressure chamber 81 through the nozzle 80 after passing through the descender due to the vibration of the vibration plate 82. For example, the first drive waveform A is a waveform for ejecting large droplets, the second drive waveform B is a waveform for ejecting medium droplets, and the third drive waveform C is a waveform for ejecting large droplets, but the ejection timings are different from those of the first drive waveform A.

[0029] Fig. 5 is an explanatory diagram illustrating conversion of a drive waveform using a triangular wave into a PWM signal and demodulation of the PWM signal into a drive waveform by the control device 50. Fig. 5 shows a second drive waveform B as an example of the drive waveform.

[0030] As shown in FIG. 5, the control device 50 compares the second drive waveform B with the triangular wave T. The control device 50 generates a PWM signal that is High when the voltage value (hereinafter also simply referred to as value) of the second drive waveform B is equal to or greater than the value of the triangular wave T, and is Low when the value of the second drive waveform B is less than the value of the triangular wave T. For example, t1 to t12 in FIG. 5 indicate the times when the signal switches between High and Low. Time passes from t1 to t12. t1, t3, t5, t7, t9, and t11 are the times when the signal switches from High to Low, and t2, t4, t6, t8, t10, and t12 are the times when the signal switches from Low to High.

[0031] The control device 50 differentiates the PWM signal and then calculates the absolute value of the differentiated result. As shown in Fig. 5, for example, at each of time points t1 to t12, V2 is calculated as the absolute value, and at time points other than time points t1 to t12, 0 is calculated as the absolute value. As shown in Fig. 5, a differentiated waveform that rises at time points t1 to t12 is generated.

[0032] The control device 50 acquires the value of the triangular wave T at the rising edge of the differentiated waveform, i.e., from time t1 to time t12. Therefore, the time between two consecutive time points is shorter (smaller) than the period of the triangular wave T. The control device 50 retains the acquired value until the next time point. That is, the value of the triangular wave T acquired at time point tn is retained until time point tn+1 (n = 1, 2, ...). The second drive waveform B' is demodulated using the retained value. More specifically, the control device 50 demodulates the second drive waveform B' using the absolute value signal S2 and the triangular wave T. The control device 50 maintains the voltage value at the intersection with the triangular wave T at time point t1 from time point t1 to time point t2, and then increases the voltage at time point t2 to the voltage value at the intersection with the triangular wave T. The control device 50 maintains the voltage value at the intersection with the triangular wave T at time t2 from time t2 to time t3, and then increases the voltage to the voltage value at the intersection with the triangular wave T at time t3. The control device 50 maintains the voltage value at the intersection with the triangular wave T at time t3 from time t3 to time t4, and then increases the voltage to the voltage value at the intersection with the triangular wave T at time t4. Here, the voltage value at the intersection with the triangular wave T at time t4, the voltage value at the intersection with the triangular wave T at time t5, the voltage value at the intersection with the triangular wave T at time t6, the voltage value at the intersection with the triangular wave T at time t7, and the voltage value at the intersection with the triangular wave T at time t8 are the same voltage value. Therefore, the control device 50 maintains the voltage at time t4 from time t4 to time t9. Subsequently, the control device 50 decreases the voltage to the voltage value at the intersection with the triangular wave T at time t9. Furthermore, the control device 50 maintains the voltage at time t9 from time t9 to time t10, and reduces the voltage at time t10 to a voltage value at which the voltage intersects with the triangular wave T at time t10. The voltage value at which the voltage intersects with the triangular wave T at time t10, the voltage value at which the voltage intersects with the triangular wave T at time t11, and the voltage value at which the voltage intersects with the triangular wave T at time t12 are the same voltage value. For this reason, the control device 50 maintains the voltage at time t10 from time t10 to time t12.

[0033] The triangular wave T is a voltage for demodulation and is also a drive voltage that deforms the piezoelectric element 83. The second drive waveform B' is demodulated by the drive voltage of the triangular wave T. Since the piezoelectric element 83 is driven by the second drive waveform B', i.e., the drive voltage, insufficient deformation of the piezoelectric element 83 is suppressed, and ink of the desired size is ejected.

[0034] Conversion to PWM signals and demodulation from PWM signals in the first drive waveform A and the third drive waveform C are performed in the same way as for the second drive waveform B, so a detailed explanation will be omitted. Note that the first drive waveform A' and the third drive waveform C' are demodulated from the first drive waveform A and the third drive waveform C. Since the piezoelectric element 83 is driven by the first drive waveform A' and the third drive waveform C', i.e., the drive voltage, insufficient deformation of the piezoelectric element 83 is suppressed, and ink of the desired size is ejected.

[0035] Next, the generation of a multiplexed signal in the control device 50 and demodulation from the multiplexed signal will be described. As shown in FIG. 3, the first drive waveform generator 51 generates the first drive waveform A. The first drive waveform generator 51 outputs the generated first drive waveform A to the comparator 51a. The comparator 51a receives the first drive waveform A and a triangular wave generated by the triangular wave generator 57. The first drive waveform A and the triangular wave are analog signals. The comparator 51a outputs a High signal to the differentiator 51b when the value of the first drive waveform A is equal to or greater than the value of the triangular wave T. Furthermore, the comparator 51a outputs a Low signal to the differentiator 51b when the value of the first drive waveform A is less than the value of the triangular wave T. That is, the comparator 51a outputs a PWM signal to the differentiator 51b. The PWM signal is input to the differentiator 51b. The differentiator 51b differentiates the PWM signal. That is, the differentiator 51b extracts the change points of the PWM signal as differential values. The differentiator 51b outputs the differential values ​​to the absolute value calculator 51c. The differential values ​​are input to the absolute value calculator 51c. The absolute value calculator 51c outputs the absolute value of the differential value to the level shifter 51d.

[0036] As shown in FIG. 3, the second drive waveform generator 52 generates the second drive waveform B. The second drive waveform generator 52 outputs the generated second drive waveform B to the comparator 52a. The comparator 52a receives the second drive waveform B and a triangular wave generated by the triangular wave generator 57. The second drive waveform B is an analog signal. The comparator 52a outputs a High signal to the differentiator 52b when the value of the second drive waveform B is equal to or greater than the value of the triangular wave T. The comparator 52a also outputs a Low signal to the differentiator 52b when the value of the second drive waveform B is less than the value of the triangular wave T. That is, the comparator 52a outputs a PWM signal to the differentiator 52b. The PWM signal is input to the differentiator 52b. The differentiator 52b differentiates the PWM signal. That is, the differentiator 52b extracts the change points of the PWM signal as differential values. The differentiator 52b outputs the differential value to the absolute value calculator 52c, which receives the differential value. The absolute value calculator 52c outputs the absolute value of the differential value to the level shifter 52d.

[0037] As shown in FIG. 3, the third drive waveform generator 53 generates the third drive waveform C. The third drive waveform generator 53 outputs the generated third drive waveform C to the comparator 53a. The comparator 53a receives the third drive waveform C and a triangular wave generated by the triangular wave generator 57 as inputs. The third drive waveform C is an analog signal. The comparator 53a outputs a High signal to the differentiator 53b when the value of the third drive waveform C is equal to or greater than the value of the triangular wave T. Furthermore, the comparator 53a outputs a Low signal to the differentiator 53b when the value of the third drive waveform C is less than the value of the triangular wave T. That is, the comparator 53a outputs a PWM signal to the differentiator 53b. The PWM signal is input to the differentiator 53b. The differentiator 53b differentiates the PWM signal. That is, the differentiator 53b extracts the change points of the PWM signal as differential values. Differentiator 53b outputs the differentiated value to absolute value calculator 53c. The differentiated value is input to absolute value calculator 53c. Absolute value calculator 53c outputs the absolute value of the differentiated value to level shifter 53d. Comparators 51a to 53a correspond to the first conversion unit or the second conversion unit.

[0038] FIG. 6 is an explanatory diagram illustrating a state in which the absolute values ​​of the differential values ​​whose levels have been adjusted by the level shifters 51d to 53d are combined. Each level shifter 51d to 53d obtains the absolute value of the differential value from each absolute value calculator 51c to 53c. The absolute value of the differential value constitutes an absolute value signal. The absolute value signal has a pulse waveform. Each level shifter 51d to 53d adjusts the level (magnitude) of the absolute value signal. The magnitude of the absolute value signal indicates the magnitude of the absolute value. The magnitude of the absolute value signal after adjustment differs among the level shifters 51d to 53d.

[0039] 6, if the magnitude of the absolute value signal S1 adjusted by the level shifter 51d is V1, the magnitude of the absolute value signal S2 adjusted by the level shifter 52d is V2, and the magnitude of the absolute value signal S3 adjusted by the level shifter 53d is V3, the magnitudes of V1, V2, and V3 are different from one another. That is, the level shifter 51d adjusts the absolute value of the absolute value signal S1 to a magnitude different from the absolute value of the absolute value signal S2 and the absolute value of the absolute value signal S3. Furthermore, the level shifter 52d adjusts the absolute value of the absolute value signal S2 to a magnitude different from the absolute value of the absolute value signal S1 and the absolute value of the absolute value signal S3. Furthermore, the level shifter 53d adjusts the absolute value of the absolute value signal S3 to a magnitude different from the absolute value of the absolute value signal S1 and the absolute value of the absolute value signal S2.

[0040] The level shifters 51d-53d output level-adjusted absolute value signals S1-S3 to the combiner 54. The combiner 54 acquires and combines the absolute value signals S1-S3. Specifically, as shown in FIG. 6, the combiner 54 arranges the acquired absolute value signals S1-S3 in time series. For example, the combiner 54 arranges the absolute value signal S2 corresponding to the second drive waveform B so that it corresponds to time points t1-t12. Similarly, the combiner 54 arranges the absolute value signals S1, S3 corresponding to the first drive waveform A and the third drive waveform C so that it corresponds to the rising edges of the absolute value signals S1, S3. The combined absolute value signals S1-S3 corresponding to the first drive waveform A, the second drive waveform B, and the third drive waveform C form a multiplexed signal. The absolute value calculators 51c-53c and the level shifters 51d-53d correspond to the first or second generation unit. The differentiators 51b to 53b, the absolute value calculators 51c to 53c, the level shifters 51d to 53d, and the combiner 54 correspond to a multiplexing unit.

[0041] The combiner 54 outputs a multiplexed signal to each selector 55(n). For example, the controller 50a generates a command to select the first drive waveform A, the second drive waveform B, or the third drive waveform C to be input to each actuator 88 based on a print job received from the external device 100. The controller 50a outputs the generated command to each selector 55(n). The selector 55(n) receives the multiplexed signal and the command, and selects from the multiplexed signal an absolute value signal corresponding to either the first drive waveform A, the second drive waveform B, or the third drive waveform C based on the command. Each selector 55(n) identifies the absolute value signals S1 to S3, i.e., the first drive waveform to the third drive waveform, based on the magnitudes V1 to V3. When the command from the controller 50a is to select the first drive waveform, the selector 55(n) selects the signal with an absolute value of V1, i.e., the absolute value signal S1. When the command from the controller 50a is to select the second drive waveform, the selector 55(n) selects a signal whose absolute value is V2, i.e., absolute value signal S2. When the command from the controller 50a is to select the third drive waveform, the selector 55(n) selects a signal whose absolute value is V3, i.e., absolute value signal S3.

[0042] Each selector 55(n) outputs the absolute value signal S1, S2, or S3 selected by the selector 55(n) to each demodulator 56(n). Each demodulator 56(n) receives the absolute value signal S1, S2, or S3 and a triangular wave generated by a triangular wave generator 57. Each demodulator 56(n) demodulates a first drive waveform A' based on the absolute value signal S1 and the triangular wave, demodulates a second drive waveform B' based on the absolute value signal S2 and the triangular wave, and demodulates a third drive waveform C' based on the absolute value signal S3 and the triangular wave. That is, each demodulator 56(n) reproduces the absolute value signal S1 as the first drive waveform A', reproduces the absolute value signal S2 as the first drive waveform B', and reproduces the absolute value signal S3 as the first drive waveform C'. Each demodulator 56(n) then outputs to each actuator 88. Each actuator 88 is driven by a first drive waveform A', a second drive waveform B', or a third drive waveform C'.

[0043] In the printing device according to the first embodiment, by using a triangular wave and a PWM signal to generate and demodulate a multiplexed signal, it is possible to suppress insufficient deformation of the nozzle 80, i.e., insufficient deformation of the piezoelectric element 83.

[0044] (Embodiment 2) The present invention will be described below with reference to the drawings showing a printing device according to a second embodiment. Of the components according to the second embodiment, the same components as those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted. Figure 7 is a block diagram showing a control device 50 and an actuator 88.

[0045] In the second embodiment, the control device 50 includes width adjusters 51e to 53e instead of the level shifters 51d to 53d. The absolute value calculators 51c to 53c and the width adjusters 51e to 53e correspond to the first generation unit or the second generation unit. FIG. 8 is an explanatory diagram illustrating a state in which the absolute values ​​of the differential values ​​whose widths have been adjusted by the width adjusters 51e to 53e are combined. The width adjuster 51e acquires the absolute value from the absolute value calculator 51c. That is, the width adjuster 51e receives an absolute value signal S1 having a pulse waveform. The width adjuster 51e adjusts the width of the acquired absolute value signal S1. The width adjuster 52e acquires the absolute value from the absolute value calculator 52c. That is, the width adjuster 52e receives an absolute value signal S2 having a pulse waveform. The width adjuster 52e adjusts the width of the acquired absolute value signal S2. The width adjuster 53e acquires the absolute value from the absolute value calculator 53c. That is, the width adjuster 53e receives the absolute value signal S3 having a pulse waveform. The width adjuster 53e adjusts the width of the acquired absolute value signal S3. The width of the absolute value signal S3 corresponds to the output time of the absolute value signal S3.

[0046] For example, as shown in FIG. 8, if the width of the absolute value signal S1 adjusted by the width adjuster 51e is the width D1 of the absolute value signal S1, the width of the absolute value signal S2 adjusted by the width adjuster 52e is the width D2 of the absolute value signal S2, and the width of the absolute value signal S3 adjusted by the width adjuster 53e is the width D3 of the absolute value signal S3, the width D1 of the absolute value signal S1, the width D2 of the absolute value signal S2, and the width D3 of the absolute value signal S3 are different from one another. That is, each width adjuster 51e to 53e adjusts the width D1 of the absolute value signal S1, the width D2 of the absolute value signal S2, and the width D3 of the absolute value signal S3 so that they are different from one another. Each width adjuster 51e to 53e adjusts the width D1 of the absolute value signal S1, the width D2 of the absolute value signal S2, and the width D3 of the absolute value signal S3, i.e., the width of the pulse waveform, in predetermined time units. The predetermined time is, for example, 10 to 90 nsec. The width of the pulse waveform is longer than the control period of the control device 50. For example, the predetermined time is the same length as the control period, and the width of the pulse waveform is expressed as the predetermined time (= control period) × α (α is a natural number equal to or greater than 2). The width D1 of the absolute value signal S1, the width D2 of the absolute value signal S2, and the width D3 of the absolute value signal S3, i.e., the width of the pulse waveform, are longer than the control period. The control period corresponds to, for example, the clock frequency of the CPU. The clock frequency of the CPU is, for example, several hundred MHz. If the clock frequency of the CPU is 100 MHz, the control period is 10 nsec.

[0047] The width adjusters 51e-53e output the width-adjusted absolute value signals S1-S3 to the combiner 54. The combiner 54 acquires and combines the absolute value signals S1-S3. Specifically, as shown in FIG. 7, the combiner 54 arranges the acquired absolute value signals S1-S3 in time series. For example, the combiner 54 arranges the absolute value signal S2 corresponding to the second drive waveform B so that it corresponds to times t1-t12. Similarly, the combiner 54 arranges the absolute value signals S1, S3 corresponding to the first drive waveform A and the third drive waveform C so that it corresponds to the rising edges of the absolute value signals S1, S3. The combined absolute value signals S1-S3 corresponding to the first drive waveform A, the second drive waveform B, and the third drive waveform C form a multiplexed signal.

[0048] The combiner 54 outputs a multiplexed signal to each selector 55(n). The selector 55(n) receives the multiplexed signal and selects an absolute value corresponding to either the first drive waveform A, the second drive waveform B, or the third drive waveform C. Each selector 55(n) identifies the first drive waveform, the second drive waveform, or the third drive waveform based on the width D1 of the absolute value signal S1, the width D2 of the absolute value signal S2, and the width D3 of the absolute value signal S3. The selection of the absolute value is determined based on, for example, a print job received from the external device 100. That is, the control device 50 determines the drive waveform to be input to each actuator 88 based on the print job received from the external device 100. Each selector 55(n) selects the drive waveform (absolute value) to be input to the actuator 88 corresponding to it. Note that the width D1 of the absolute value signal S1, the width D2 of the absolute value signal S2, and the width of the absolute value signal S3 are used to identify the first drive waveform, the second drive waveform, and the third drive waveform, and are therefore shorter than the period of the triangular wave T. This is because if the width D1 of the absolute value signal S1, the width D2 of the absolute value signal S2, and the width of the absolute value signal S3 are greater than the period of the triangular wave T, demodulation becomes impossible.

[0049] (Embodiment 3) The present invention will be described below with reference to the drawings showing a printing device according to a third embodiment. In the third embodiment, components similar to those in the first or second embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. FIG. 9 is a block diagram showing a control device 50 and an actuator 88. Unlike the second embodiment, the control device 50 does not include width adjusters 51e-53e. Differentiator 51b includes a CR circuit 51f, differentiator 52b includes a CR circuit 52f, and differentiator 52b includes a CR circuit 52f. The CR circuits 51f-53f have different time constants. Since the widths D1, D2, and D3 of the absolute value signals S1-S3 depend on the time constants of the CR circuits 51f-53f, the widths D1, D2, and D3 are different from one another. The capacitors of the CR circuits 51f-53f may be variable capacitors, and the resistors may be variable resistors. The time constant can be changed by changing the capacitance of the variable capacitor or the resistance of the variable resistor, thereby changing the widths D1, D2, and D3. The capacitance of the variable capacitor or the resistance value of the variable resistor may be changed by a command from the external device 100 or the controller 50a.

[0050] (Change example 1) The printing device 1 may have the following configuration. Fig. 10 is a block diagram showing an inkjet head 8 and a control device 50. As shown in Fig. 10, the control device 50, i.e., the controller 50a, first to third drive waveform generators 51 to 53, comparators 51a to 53a, differentiators 51b to 53b, absolute value calculators 51c to 53c, level shifters 51d to 53d, a synthesizer 54, a selector 55(n), a demodulator 56(n), and a triangular wave generator 57 may be provided to the inkjet head 8. When a width adjuster 51e is used instead of the level shifters 51d to 53d, the width adjuster 51e may be provided to the inkjet head 8. A control device 50 may be provided for each inkjet head 8.

[0051] (Change example 2) The printing device 1 may have the following configuration. Figure 11 is a block diagram showing the inkjet head 8, main body board 58, and relay board 59. The printing device 1 includes the main body board 58 and relay board 59. The relay board 59 is provided on the carriage 6. The main body board 58 is provided in a location other than the carriage 6 and the inkjet head 8. The main body board 58, relay board 59, and inkjet head 8 are connected to each other.

[0052] The main board 58 is provided with the first to third drive waveform generators 51 to 53, comparators 51a to 53a, differentiators 51b to 53b, absolute value calculators 51c to 53c, level shifters 51d to 53d, a synthesizer 54, and a triangular wave generator 57. The relay board 59 is provided with the controller 50a. The inkjet head 8 is provided with a selector 55(n) and a demodulator 56(n). The elements provided on the main board 58, the relay board 59, and the inkjet head 8 constitute the control device 50.

[0053] (Change example 3) The printing device 1 may have the following configuration. Figure 12 is a block diagram showing the inkjet head 8, main body board 58, and relay board 59. The printing device 1 includes the main body board 58 and relay board 59. The relay board 59 is provided on the carriage 6. The main body board 58 is provided in a location other than the carriage 6 and the inkjet head 8. The main body board 58, relay board 59, and inkjet head 8 are connected to each other.

[0054] The relay board 59 is provided with the first to third drive waveform generators 51 to 53, comparators 51a to 53a, differentiators 51b to 53b, absolute value calculators 51c to 53c, level shifters 51d to 53d, a synthesizer 54, and a triangular wave generator 57. The main board 58 is provided with the controller 50a. The inkjet head 8 is provided with a selector 55(n) and a demodulator 56(n). The elements provided on the main board 58, relay board 59, and inkjet head 8 constitute the control device 50.

[0055] (Change example 4) The printing device 1 may have the following configuration. Figure 13 is a block diagram showing the inkjet head 8 and main body board 58. The printing device 1 includes the main body board 58. The main body board 58 is provided in a location other than the carriage 6 and the inkjet head 8. The main body board 58 and the inkjet head 8 are connected to each other.

[0056] A main body board 58 is provided with a controller 50a, first to third drive waveform generators 51 to 53, comparators 51a to 53a, differentiators 51b to 53b, absolute value calculators 51c to 53c, level shifters 51d to 53d, a synthesizer 54, and a triangular wave generator 57. A selector 55(n) and a demodulator 56(n) are provided on the inkjet head 8. The elements provided on the main body board 58 and the inkjet head 8 constitute a control device 50.

[0057] (Change example 5) The printing device 1 may have the following configuration. Figure 14 is a block diagram showing the inkjet head 8 and a relay board 59. The printing device 1 includes the relay board 59. The relay board 59 is provided on the carriage 6. The relay board 59 and the inkjet head 8 are connected to each other.

[0058] A relay board 59 is provided with a controller 50a, first to third drive waveform generators 51 to 53, comparators 51a to 53a, differentiators 51b to 53b, absolute value calculators 51c to 53c, level shifters 51d to 53d, a synthesizer 54, and a triangular wave generator 57. A selector 55(n) and a demodulator 56(n) are provided on the inkjet head 8. The elements provided on the relay board 59 and the inkjet head 8 constitute a control device 50.

[0059] It should be noted that a computer program (program product) can be deployed to be executed on a single computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communications network.

[0060] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is intended to include all modifications within the scope of the claims and the scope equivalent to the claims. The features described in each embodiment can be mutually combined. Furthermore, independent claims and dependent claims described in the claims can be mutually combined in any and all combinations, regardless of the reference format. Furthermore, although the claims use a format in which a claim references two or more other claims (multiple claim format), this is not limiting. A multiple claim (multi-multi claim) that references at least one other multiple claim may also be used. [Explanation of symbols]

[0061] 1 Printing device 50 Control device 50a controller 51 First drive waveform generator 52 Second drive waveform generator 53 Third drive waveform generator 51a~53a Comparator 51b~53b Differentiator 51c~53c Absolute value calculator 51d~53d Level shifter 54 Synthesizer 55(n) Selector 56(n) Demodulator 57 Triangle wave generator 80 nozzles 83 Piezoelectric 88 Actuator

Claims

1. a nozzle that ejects a liquid using an energy imparting element; a first conversion unit that converts a first drive waveform for driving the energy imparting element into a first PWM signal using a triangular wave; a second conversion unit that converts a second drive waveform for driving the energy imparting element into a second PWM signal using a triangular wave; a multiplexing unit that generates a multiplexed signal based on a plurality of PWM signals including the first PWM signal and the second PWM signal; a demodulator that demodulates one of a plurality of drive waveforms including the first drive waveform and the second drive waveform based on the multiplexed signal; A printing device comprising:

2. The multiplexing unit a first differentiator that differentiates the first PWM signal to generate a first differentiated signal; a first generator that generates a first signal based on the first differential signal; a second differentiator that differentiates the second PWM signal to generate a second differentiated signal; a second generator that generates a second signal based on the second differential signal; and generating the multiplexed signal based on a plurality of signals including the first signal and the second signal; The printing device of claim 1 .

3. the first signal is a first absolute value signal indicating an absolute value of the first differential signal, the second signal is a second absolute value signal indicating an absolute value of the second differential signal, the first generator adjusts the absolute value of the first absolute value signal; The second generating unit adjusts the absolute value of the second absolute value signal to a magnitude different from the absolute value of the first absolute value signal. The printing device according to claim 2 .

4. the first signal is a first absolute value signal that indicates an absolute value of the first differential signal and has a pulse waveform, the second signal is a second absolute value signal that indicates an absolute value of the second differential signal and has a pulse waveform, the first generating unit adjusts a width of a pulse waveform of the first absolute value signal; The second generating unit adjusts the width of the pulse waveform of the second absolute value signal to a size different from the width of the pulse waveform of the first absolute value signal. The printing device according to claim 2 .

5. The width of the pulse waveform is adjusted in units of 10 to 90 nsec. The printing device according to claim 4 .

6. The width of the pulse waveform is adjusted so that it is longer than the control period. The printing device according to claim 4 .

7. the first differentiator and the second differentiator each have a CR circuit; The time constants of the CR circuits of the first differentiator and the second differentiator are different. The printing device according to claim 4 .

8. a time between two successive rising points in the differentiated waveform represented by the first differentiated signal is shorter than a period of the triangular wave; The time between two successive rising points in the differential waveform represented by the second differential signal is shorter than the period of the triangular wave. The printing device according to claim 2 .

9. A printing method for printing by ejecting a liquid from a nozzle using an energy imparting element, converting a first driving waveform for driving the energy imparting element into a first PWM signal using a triangular wave; converting a second driving waveform for driving the energy imparting element into a second PWM signal using a triangular wave; multiplexing a plurality of signals based on a plurality of PWM signals, including a first signal based on the first PWM signal and a second signal based on the second PWM signal, to generate a multiplexed signal; demodulating one of the drive waveforms from a plurality of drive waveforms including the first drive waveform and the second drive waveform based on the multiplexed signal; Printing method.

10. A computer program executable on a printing device having a nozzle that ejects a liquid using an energy application element, The printing device converting a first driving waveform for driving the energy imparting element into a first PWM signal using a triangular wave; converting a second driving waveform for driving the energy imparting element into a second PWM signal using a triangular wave; multiplexing a plurality of signals based on a plurality of PWM signals, including a first signal based on the first PWM signal and a second signal based on the second PWM signal, to generate a multiplexed signal; demodulating one of the drive waveforms from a plurality of drive waveforms including the first drive waveform and the second drive waveform based on the multiplexed signal; A computer program that executes a process.

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