JP7476859B2 - Head and printing device - Google Patents

Description

This technology relates to a head that ejects liquid and a printing device.

Some printers generate first through fourth drive pulses with different amplitudes as drive signals to drive the piezoelectric elements of the nozzles. During one cycle to print one pixel, the first through fourth drive pulses are generated continuously. One of the first through fourth drive pulses is selected and applied to the piezoelectric element of each nozzle. The nozzle ejects an amount of ink corresponding to the amplitude of the selected drive pulse, forming a dot of the desired size (see Patent Document 1).

JP 2010-142978 A

Four drive pulses are generated consecutively during one cycle, but only one drive pulse is selected. Therefore, the time allocated to the three unselected drive pulses becomes the nozzle standby time.

This disclosure has been made in light of these circumstances, and aims to provide a head and printing device that can adjust the amplitude of the drive waveform applied to the energy imparting element and reduce the nozzle standby time.

A head according to an embodiment of the present disclosure includes a nozzle that ejects liquid by an energy imparting element, and a multiplexing unit that generates a time division multiplexed signal that can transmit the first data and the second data on a single signal line, the first data being arranged based on at least first data indicating a first drive waveform and second data indicating a second drive waveform different from the first drive waveform, such that a third portion that is part of the second drive waveform is between a first portion that is part of the first drive waveform and a second portion that is part of the first drive waveform, and the second portion is between the third portion and a fourth portion that is part of the second drive waveform, and the first data and the second data are arranged on a single signal line, and a separation unit that separates the first drive waveform signal indicating the first drive waveform or the second drive waveform signal indicating the second drive waveform from the time division multiplexed signal generated by the multiplexing unit, and the energy imparting element is driven by the first drive waveform signal or the second drive waveform signal separated by the separation unit.

A printing device according to an embodiment of the present disclosure includes a multiplexing unit that generates a time division multiplexed signal that can transmit the first data and the second data on a single signal line, the time division multiplexed signal being arranged so that a third portion that is part of the second drive waveform is between a first portion that is part of the first drive waveform and a second portion that is part of the first drive waveform, and the second portion is between the third portion and a fourth portion that is part of the second drive waveform, based on at least first data indicating a first drive waveform and second data indicating a second drive waveform different from the first drive waveform, the first data and the second data being arranged so that a third portion that is part of the second drive waveform is between the third portion and a fourth portion that is part of the second drive waveform, the first data and the second data being arranged on a single signal line, a separation unit that separates the first drive waveform signal indicating the first drive waveform or the second drive waveform signal indicating the second drive waveform from the time division multiplexed signal generated by the multiplexing unit, an energy imparting element driven by the first drive waveform signal or the second drive waveform signal separated by the separation unit, a head including a nozzle that ejects liquid by driving the energy imparting element, and a transport unit that transports a print medium printed with the liquid ejected from the nozzle.

In the head and printing device according to one embodiment of the present disclosure, a time division multiplexed signal is generated based on first data indicating a first drive waveform and second data indicating a second drive waveform different from the first drive waveform. In the time division multiplexed signal, a third portion which is a part of the second drive waveform is between a first portion which is a part of the first drive waveform and a second portion which is a part of the first drive waveform, and a second portion is between the third portion and a fourth portion which is a part of the second drive waveform. From the generated time division multiplexed signal, a first drive waveform signal indicating the first drive waveform or a second drive waveform signal indicating the second drive waveform is separated. The energy imparting element is driven by the first drive waveform signal or the second drive waveform signal. By selecting the first drive waveform signal or the second drive waveform signal, the amplitude of the drive waveform applied to the energy imparting element can be adjusted. In addition, one cycle for printing one pixel includes only the cycle of any one of the selected drive waveforms, and does not include the cycle of the drive waveform that was not selected. Therefore, the waiting time of the nozzle can be reduced.

1 is a plan view illustrating a printing device according to a first embodiment; FIG. 2 is a simplified partial enlarged cross-sectional view of an ink-jet head. FIG. 2 is a block diagram of a control device. 4 is an explanatory diagram illustrating an example of driving waveforms A, B, and C. FIG. 2A to 2C are explanatory diagrams illustrating an example of time series data, an analog signal, and a time division multiplexed signal. FIG. 2 is an explanatory diagram illustrating the relationship between a time division multiplexed signal and a synchronization signal. 5 is a schematic diagram of a drive waveform input to an actuator by opening and closing an n-th switch. FIG. 10 is a flowchart illustrating a printing process performed by the control device. FIG. 11 is a block diagram of a control device according to a second embodiment. FIG. 2 is an explanatory diagram illustrating the relationship between an analog signal and a time-division signal. FIG. 11 is a block diagram of a control device according to a modified example. FIG. 11 is a block diagram of a control device according to a third embodiment. FIG. 13 is a block diagram of a control device according to a fourth embodiment. FIG. 13 is a block diagram of a control device according to a fifth embodiment. 4 is an explanatory diagram illustrating the relationship between an analog signal output from a D/A converter and a voltage supplied to an amplifier. FIG.

(Embodiment 1)
The present invention will be described below based on 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 up and down will also be used.

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, ie, a recording paper 200, 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 includes a carriage 6, a subtank 7, four inkjet heads 8, and a circulation pump 10.

Above the platen 2, two guide rails 11 and 12 are provided, extending to the left and right, 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. By driving 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, while supporting the four inkjet heads 8, the carriage 6 performs a first movement in which the heads are moved from one position to another position 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.

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 disposed below the ink ejection device 3. The cap 20 is disposed at the right end of the guide rails 11 and 12, and the flushing receiver 21 is disposed at the left end of the guide rails 11 and 12. The cap 20 and the flushing receiver 21 may be disposed in reverse.

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

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

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. In other words, the four inkjet heads 8 correspond to four colors of ink, respectively, and are connected to four ink chambers.

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.

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 nozzle 80. Ink that is not ejected from the nozzle 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 in the scanning direction together with the carriage 6.

As shown in FIG. 1, the transport roller 4 is disposed upstream (rear) of the platen 2 in the transport direction. The transport roller 5 is disposed 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 includes a control device 50. The control device 50 includes a CPU or logic circuit (e.g., FPGA), a non-volatile memory, a RAM, or other memory 55, and the like. The control device 50 receives a print job and drive waveform data from the external device 100 and stores them in the memory 55. The control device 50 controls the drive of the ink ejection device 3 and the transport roller 4, etc. based on the print job, and executes the print process.

Figure 2 is a simplified, partially enlarged cross-sectional view of the inkjet head 8. The inkjet head 8 has a number of pressure chambers 81. The pressure chambers 81 form a number 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.

A second common electrode 86 is provided inside the piezoelectric body 83. The second common electrode 86 is disposed above each pressure chamber 81 and above the first common electrode 84. The second common electrode 86 is disposed in a position that does not face the first common electrode 84. An individual electrode 85 is formed on the upper surface of the piezoelectric body 83 above each pressure chamber 81. The individual electrode 85 faces the first common electrode 84 and the second common electrode 86 above and below, sandwiching the piezoelectric body 83. 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.

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 nozzles 80 form a plurality of nozzle rows extending along the rows of pressure chambers.

The first common electrode 84 is connected to the COM terminal, which in this embodiment is ground, and the second common electrode 86 is connected to the VCOM terminal. The VCOM voltage is higher than the COM voltage. The individual electrode 85 is connected to the switch group 54 (see FIG. 3). 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 through the nozzle 80.

Figure 3 is a block diagram of the control device 50. The control device 50 includes a control circuit 51, a D/A converter 52, an amplifier 53, a group of switches 54, and a memory 55. Drive waveform data is stored in the memory 55. The drive waveform data is data indicating the voltage waveform applied to the individual electrodes 85, i.e., the drive waveform that drives the actuator 88, and is quantized data. In this embodiment, the drive waveform data Da, Db, and Dc are stored in the memory 55.

The D/A converter 52 converts the digital signal into an analog signal. The amplifier 53 amplifies the analog signal. The switch group 54 includes a plurality of n-th switches 54(n) (n=1, 2, ...). The n-th switch 54(n) is, for example, configured with an analog switch IC. One end of each of the plurality of n-th switches 54(n) is connected to the amplifier 53 via a common bus. The other end of each of the n-th switches 54(n) is connected to each individual electrode 85 corresponding to the plurality of nozzles 80. In other words, one n-th switch 54(n) is provided for each actuator 88.

The first capacitor 89a is formed by the individual electrode 85, the first common electrode 84, and the piezoelectric body 83. The second capacitor 89b is formed by the individual electrode 85, the second common electrode 86, and the piezoelectric body 83.

FIG. 4 is an explanatory diagram for explaining an example of the driving waveforms A, B, and C. The driving waveforms A, B, and C are waveforms for deforming the piezoelectric body 83, vibrating the vibration plate 82, and discharging the ink in the pressure chamber 81 through the nozzle 80 after passing through the descender by the vibration of the vibration plate 82. For example, the driving waveform A is a waveform for discharging a large ball, the driving waveform B is a waveform for discharging a medium ball, and the driving waveform C is a waveform for discharging a large ball, but the discharging timing is different from that of the driving waveform A. In FIG. 4, the right side shows a state earlier than the left side. The same is true for FIGS. 5 to 7, 10, and 15. The driving waveform data Da is quantized data of the driving waveform A, the driving waveform data Db is quantized data of the driving waveform B, and the driving waveform data Dc is quantized data of the driving waveform C. The drive waveform data Da has quantized data Ak (k=0, 1, 2, . . . ), the drive waveform data Db has quantized data Bk, and the drive waveform data Dc has quantized data Ck.

FIG. 5 is an explanatory diagram for explaining an example of time series data, an analog signal, and a time division multiplexed signal. In FIG. 5, A, B, and C indicate that they correspond to the drive waveforms A, B, and C, respectively. When driving the actuator 88, the control circuit 51 accesses the memory 55 to obtain the drive waveform data Da, Db, and Dc, and creates the time series data. The time series data is data Ak, Bk, and Ck arranged in order with a time interval Δt provided, and arranged in the order of A0, B0, C0, A1, B1, C1, ..., Ak, Bk, and Ck. The time series data is a digital signal. Note that the time interval Δt is the reciprocal of a predetermined sampling frequency. The quantized data Ak, Bk, and Ck are arranged in the order of A0, B0, C0, A1, B1, C1, ..., Ak, Bk, and Ck for each time corresponding to the reciprocal of the predetermined sampling frequency. In other words, the data length of the quantized data Ak, Bk, and Ck is equal to or less than the length corresponding to the reciprocal of the predetermined sampling frequency. In addition, the quantized data A0 and the quantized data B0 are continuous, the quantized data B0 and the quantized data C0 are continuous, and the quantized data C0 and the quantized data A1 are continuous. That is, there is no quantized data C0, other quantized data, or other waveform data between the quantized data A0 and the quantized data B0. In addition, there is no quantized data A0, other quantized data, or other waveform data between the quantized data B0 and the quantized data C0. In addition, there is no quantized data B0, other quantized data, or other waveform data between the quantized data C0 and the quantized data A1. The sampling frequency is 24 MHz, and the data length of the quantized data Ak, Bk, and Ck is about 41 nS.

The control circuit 51 outputs the time series data to the D/A converter 52. As shown in FIG. 5, the D/A converter 52 converts the time series data into an analog signal and outputs it to the amplifier 53. The amplifier 53 amplifies the input analog signal and outputs it to the switch group 54. As shown in FIG. 5, the analog signal amplified by the amplifier 53 constitutes a time division multiplexed signal. In other words, the time division multiplexed signal is not an analog signal corresponding only to data Ak, an analog signal corresponding only to data Bk, or an analog signal corresponding only to data Ck. In addition, the time division multiplexed signal is a signal in which at least an analog signal corresponding to a total of three data sets, one data Ak, one data Bk, and one data Ck, and an analog signal corresponding to a total of three data sets, one data Ak+1, one data Bk+1, and one data Ck+1, are continuous in time series. For example, there is one time division multiplexed signal in FIG. 5. In Fig. 5, the analog signal corresponding to data C0 appears to be isolated, but the analog signal corresponding to a total of three data sets, data A0, data B0, and data C0, in which data A0 and data B0 are 0, is a result of being chronologically continuous with an analog signal corresponding to a total of three data sets, data A1, data B1, and data C1, in which data A1 is 0. Also, the analog signal corresponding to a set of data Ak and data Bk appears to be isolated, but the analog signal corresponding to a total of three data sets, data Ak-1, data Bk-1, and data Ck-1, in which data Ck-1 is 0, is a result of being chronologically continuous with an analog signal corresponding to a total of three data sets, data Ak, data Bk, and data Ck. Also, the reason why the analog signal corresponding to the set of data Ak-1 and data Bk-1 appears to be isolated is the same. Therefore, the analog signal in Fig. 5 can be treated as one time division multiplexed signal. In the time division multiplexed signal, if the part corresponding to data Ak-1 is the first part, the part corresponding to data Ak is the second part, the part corresponding to data Bk-1 is the third part, and the part corresponding to data Bk is the fourth part, then the third part is between the first part and the second part, and the second part is between the third part and the fourth part . In other words, the first part and the third part are continuous, the third part and the second part are continuous, and the second part and the fourth part are continuous. That is, in the time division multiplexed signal, there are no second part, fourth part, or other waveforms between the first part and the third part. Also, in the time division multiplexed signal, there are no first part, fourth part, or other waveforms between the third part and the second part. Also, in the time division multiplexed signal, there are no first part, third part, or other waveforms between the second part and the fourth part. Note that a similar relationship is established between data Ak and Ck, and a similar relationship is established between data Bk and Ck. The control circuit 51, the D/A converter 52, the amplifier 53 and the memory 55 constitute a multiplexing section. One time division multiplexed signal fits into one ejection drive period. For example, if the ejection drive frequency (ejection frequency) is 100 kHz, one ejection drive period (ejection period) is 10 μS, and one time division multiplexed signal has a length of less than 10 μS. It is preferable that there are three or more pieces of each of data Ak, data Bk and data Ck in one time division multiplexed signal. The reason for this will be described later.

The control circuit 51 outputs to the switch group 54 a switch control signal S1 that controls the opening and closing of the multiple nth switches 54(n), a synchronization signal S2a corresponding to the drive waveform A, a synchronization signal S2b corresponding to the drive waveform B, and a synchronization signal S2c corresponding to the drive waveform C. The three synchronization signals S2a, S2b, and S2c are also simply referred to as synchronization signals S2 (see FIG. 3). The switch control signal S1 includes first selection information indicating the selection of one of the multiple nth switches 54(n), and second selection information indicating the selection of one of the three synchronization signals S2a, S2b, and S2c. The first selection information and the second selection information are linked.

6 is an explanatory diagram for explaining the relationship between the time division multiplexed signal and the synchronization signals S2a, S2b, and S2c. The synchronization signals S2a, S2b, and S2c are pulse waves. A time interval Δt is provided between the rising edge of the pulse of the synchronization signal S2a and the rising edge of the pulse of the synchronization signal S2b. A time interval Δt is also provided between the rising edge of the pulse of the synchronization signal S2b and the rising edge of the pulse of the synchronization signal S2c, and a time interval Δt is provided between the rising edge of the pulse of the synchronization signal S2c and the rising edge of the pulse of the synchronization signal S2a. As described above, the data Ak, Bk, and Ck constituting the time series data are arranged in order with a time interval Δt provided. Therefore, when the time division multiplexed signal is accessed at the rising edge of the pulse of the synchronization signal S2a, a driving waveform signal Pa corresponding to the data Ak and indicating the driving waveform A can be obtained. When the time division multiplexed signal is accessed at the rising edge of the pulse of the synchronization signal S2b, a driving waveform signal Pb corresponding to the data Bk and indicating the driving waveform B can be obtained. When the time division multiplexed signal is accessed at the rising edge of the pulse of the synchronization signal S2c, it is possible to obtain a drive waveform signal Pc that corresponds to the data Ck and indicates the drive waveform C. In other words, one nth switch 54(n) receives one type of time division multiplexed signal as input, and separates one of the drive waveform signal Pa indicating the drive waveform A, the drive waveform signal Pb indicating the drive waveform B, and the drive waveform signal Pc indicating the drive waveform C.

The switch group 54 opens and closes the selected nth switch 54(n) at the opening and closing timing indicated by the selected synchronization signal S2a to S2c. In other words, the switch group 54 opens and closes the nth switch 54(n) at a predetermined sampling frequency.

7 is a schematic diagram of a drive waveform input to the actuator 88 by opening and closing the nth switch 54(n). When the synchronization signal S2a is selected, the switch group 54 closes the nth switch 54(n) when the pulse of the synchronization signal S2a is in a high level section, and opens the nth switch 54(n) when the pulse of the synchronization signal S2a is in a low level section. The first capacitor 89a and the second capacitor 89b hold the charge applied to the individual electrode 85 when the nth switch 54(n) is closed, and the drive waveform A1 is input to the actuator 88 as shown in FIG. 7. In other words, the drive waveform signal Pa is separated from the time division multiplexed signal by a predetermined sampling frequency, and the actuator 88 is driven by the drive waveform signal Pa. Note that three or more pieces of data Ak are required to represent the concave and convex portions of the drive waveform signal Pa.

When the synchronization signal S2b is selected, the switch group 54 closes the n-th switch 54(n) when the pulse of the synchronization signal S2b is in a high level section, and opens the n-th switch 54(n) when the pulse of the synchronization signal S2b is in a low level section. The charge applied to the individual electrode 85 when the n-th switch 54(n) is closed is held by the first capacitor 89a and the second capacitor 89b, and the drive waveform B1 is input to the actuator 88 as shown in FIG. 7. In other words, the drive waveform signal Pb is separated from the time division multiplexed signal by a predetermined sampling frequency, and the actuator 88 is driven by the drive waveform signal Pb. Note that three or more pieces of data Bk are required to represent the concave and convex portions of the drive waveform signal Pb.

When the synchronization signal S2c is selected, the switch group 54 closes the n-th switch 54(n) when the pulse of the synchronization signal S2c is in a high level section, and opens the n-th switch 54(n) when the pulse of the synchronization signal S2c is in a low level section. The first capacitor 89a and the second capacitor 89b hold the charge applied to the individual electrode 85 when the n-th switch 54(n) is closed, and the drive waveform C1 is input to the actuator 88 as shown in FIG. 7. In other words, the drive waveform signal Pc is separated from the time division multiplexed signal by a predetermined sampling frequency, and the actuator 88 is driven by the drive waveform signal Pc. Note that three or more pieces of data Ck are required to represent the concave and convex portions of the drive waveform signal Pc.

The predetermined sampling frequency is equal to or greater than the resonant frequency of the inkjet head 8. The resonant frequency of the inkjet head 8 is the resonant frequency when the pressure chamber 81 is not filled with ink (liquid), or is the resonant frequency when the pressure chamber 81 is filled with ink. For example, if the resonant frequency of the inkjet head 8 when the pressure chamber 81 is not filled with ink is 100 kHz, the resonant frequency of the inkjet head 8 when the pressure chamber 81 is filled with ink is less than 100 kHz. Specifically, the resonant frequency of the inkjet head 8 when the pressure chamber 81 is filled with ink is 90 kHz. In other words, the resonant frequency of the inkjet head 8 when the pressure chamber 81 is not filled with ink is greater than the resonant frequency of the inkjet head 8 when the pressure chamber 81 is filled with ink.

Figure 8 is a flowchart explaining the printing process by the control device 50. The control device 50 determines whether or not a print job has been received from the external device 100 (S1). If a print job has not been received (S1: NO), the control device 50 returns the process to step S1. If a print job has been received (S1: YES), the control device 50 executes a flushing process (S2). The flushing process is a process in which ink is ejected from the nozzles 80 for purposes other than printing, and is executed, for example, by the flushing receiver 21.

The control device 50 executes one print task (S3). A print task is a unit that constitutes a print job. Specifically, it is a liquid ejection process that is performed while the inkjet head 8 moves to the right or left by the left-right width of the recording paper 200. Next, the control device 50 determines whether or not one print task is complete (S4). In one print task, the carriage 6 performs one scan. If one print task is not complete (S4: NO), the process returns to step S4. If one print task is complete (S4: YES), the control device 50 determines whether or not the print job is complete (S5).

When one print task is completed (S5: YES), the control device 50 executes a flushing process (S8) and ends the print process. When one print task is not completed (S5: NO), the control device 50 judges whether it is time to execute a flushing process (S6). In one print task, the time division multiplexed signal is only an analog signal, the type of the analog signal does not change, and is composed of three types of analog signals. Even in one cycle from when the time division multiplexed signal rises to when it falls within one ejection drive period, the type of the analog signal does not change, and is composed of three types of analog signals. The flushing process is executed periodically for the maintenance of the nozzle 80. When it is time to execute a flushing process (S6: YES), the control device 50 executes the flushing process (S7) and returns the process to step S3. When it is not time to execute a flushing process (S6: NO), the control device 50 judges whether it is time to execute a non-ejection flushing process (S9).

The non-ejection flushing process is a process for preventing the nozzles 80 from drying out without ejecting ink. More specifically, it is a process for slightly deforming the piezoelectric body 83 to vibrate the surface (meniscus) of the ink, and is performed, for example, by the cap 20. The non-ejection flushing process is performed periodically. If it is time to perform the non-ejection flushing process (S9: YES), the control device 50 performs the non-ejection flushing process (S10) and returns to step S3. In step S10, the control device 50 supplies a drive waveform corresponding to the non-ejection flushing process to the individual electrode 85. If it is not time to perform the non-ejection flushing process (S9: NO), the control device 50 returns to step S3.

The control device 50 may generate the time division multiplexed signal and separate the drive waveform signal either when the flushing process is being performed (S2, S7, S8) or when the print task is being performed (S3). In other words, the time division multiplexed signal may be generated and the drive waveform signal may be separated when the actuator 88 is being driven.

In the inkjet head 8 and the printing device 1 according to the first embodiment, a time division multiplexed signal is generated based on the drive waveform data Da, Db, and Dc indicating the drive waveforms A, B, and C. From the generated time division multiplexed signal, a drive waveform signal Pa indicating the drive waveform A, a drive waveform signal Pb indicating the drive waveform B, and a drive waveform signal Pc indicating the drive waveform C are separated. The actuator 88 is driven by the drive waveform signal Pa, Pb, or Pc. By selecting the drive waveform signal Pa, Pb, or Pc, the amplitude of the drive waveform given to the actuator 88 can be adjusted. In addition, one period for printing one pixel includes only the period of any one of the selected drive waveforms A1, A2, or A3, and does not include the period of the drive waveform that was not selected. Therefore, the standby time of the nozzle 80 can be reduced.

The control circuit 51 reads the data values of the drive waveform data Da, Db, and Dc from the memory 55, arranges them in a time series, and transmits them, thereby generating a time division multiplexed signal.

The control circuit 51 inputs the data values of the drive waveform data Da, Db, and Dc to the D/A converter 52, which amplifies them in the amplifier 53, thereby increasing the amplitude of the time division multiplexed signal.

From the time division multiplexed signal, a drive waveform signal Pa indicating drive waveform A, a drive waveform signal Pb indicating drive waveform B, and a drive waveform signal Pc indicating drive waveform C are separated at a sampling frequency equal to or higher than the resonant frequency of the inkjet head 8. The resonant frequency of the inkjet head 8 is the resonant frequency when the pressure chamber 81 is not filled with ink. Therefore, the sampling error does not affect the operation of the actuator 88, and can be ignored.

From the time division multiplexed signal, a drive waveform signal Pa indicating drive waveform A, a drive waveform signal Pb indicating drive waveform B, and a drive waveform signal Pc indicating drive waveform C are separated at a sampling frequency equal to or higher than the resonant frequency of the inkjet head 8. The resonant frequency of the inkjet head 8 is the resonant frequency when the pressure chamber 81 is filled with ink. In this case, an increase in the number of switching amplifiers can be suppressed when creating a circuit.

The time division multiplexed signal is input to the switch group 54. In addition, a switch control signal S1 and synchronization signals S2a to S2c indicating the opening and closing timing are input to the nth switch 54(n). The nth switch 54(n) opens and closes based on the switch control signal S1 and the synchronization signals S2a to S2c, and can separate the drive waveform signals Pa to Pc from the time division multiplexed signal.

The control circuit 51 outputs a switch control signal S1 and synchronization signals S2a to S2c to the switch group 54, and controls the opening and closing of the nth switch 54(n).

In the first embodiment, the actuator 88 has a three-layer structure, but may have a two-layer structure. The actuator 88 is a piezoelectric type, but may also be an ink-heating inkjet type or an electrostatic force type. The number of waveform signals is not limited to three, but may be two, or four or more.

(Embodiment 2)
The present invention will be described below with reference to the drawings showing a printer 1 according to a second embodiment of the present invention. Among 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. Fig. 9 is a block diagram of the control device 50, and Fig. 10 is an explanatory diagram explaining the relationship between the analog signals 60A to 60C and the time division signals S3a to S3c.

The control device 50 includes a control circuit 51, a first D/A converter 52a, a second D/A converter 52b, a third D/A converter 52c, a second switch control unit 56, an amplifier 53, a switch group 54, and a memory 55. The second switch control unit 56 includes a first switch 56a, a second switch 56b, and a third switch 56c.

When driving the actuator 88, the control circuit 51 accesses the memory 55 to obtain drive waveform data Da, which is then output to the first D/A converter 52a. The control circuit 51 accesses the memory 55 to obtain drive waveform data Db, which is then output to the second D/A converter 52b. The control circuit 51 accesses the memory 55 to obtain drive waveform data Dc, which is then output to the third D/A converter 52c.

As shown in FIG. 10, the first D/A converter 52a, the second D/A converter 52b, and the third D/A converter 52c output analog signals 60A, 60B, and 60C, respectively. The control circuit 51 outputs a time division signal S3a corresponding to the analog signal 60A, a time division signal S3b corresponding to the analog signal 60B, and a time division signal S3c corresponding to the analog signal 60C to the switch group 54. The three time division signals S3a, S3b, and S3c are also simply referred to as time division signals S3 (see FIG. 9).

Time division signals S3a, S3b, and S3c are pulse waves. There is a time interval Δt between the rising edge of the pulse of time division signal S3a and the rising edge of the pulse of time division signal S3b. There is also a time interval Δt between the rising edge of the pulse of time division signal S3b and the rising edge of the pulse of time division signal S3c, and there is a time interval Δt between the rising edge of the pulse of time division signal S3c and the rising edge of the pulse of time division signal S3a. Each of the time division signals S3a, S3b, and S3c corresponds to each of the synchronization signals S2a, S2b, and S2c described above.

The first switch 56a closes when the pulse of the time division signal S3a is in a high level section, and opens when it is in a low level section. The second switch 56b closes when the pulse of the time division signal S3b is in a high level section, and opens when it is in a low level section. The third switch 56c closes when the pulse of the time division signal S3c is in a high level section, and opens when it is in a low level section. The first switch 56a, the second switch 56b, and the third switch 56c may be open at the same time, but are never closed at the same time. This is because if the first switch 56a, the second switch 56b, and the third switch 56c are closed at the same time, the analog signals 60A, 60B, and 60C will be mixed. Since the analog signals 60A, 60B, and 60C are not mixed, in the time division multiplexed signal, a part of the analog signal 60A is continuous with a part of the analog signal 60B, a part of the analog signal 60B is continuous with a part of the analog signal 60C, and a part of the analog signal 60C is continuous with a part of the analog signal 60A. That is, in the time division multiplexed signal, there is no analog signal 60C or analog signals of other waveforms between a part of analog signal 60A and a part of analog signal 60B. Also, in the time division multiplexed signal, there is no part of analog signal 60A or analog signals of other waveforms between a part of analog signal 60B and a part of analog signal 60C. Also, in the time division multiplexed signal, there is no part of analog signal 60B or analog signals of other waveforms between a part of analog signal 60C and a part of analog signal 60A.

A composite signal obtained by combining analog signals 60A to 60C is output from second switch control unit 56. The composite signal is similar to the analog signal shown in FIG. 5. The composite signal is amplified by amplifier 53, which outputs a time division multiplexed signal. This time division multiplexed signal is similar to the time division multiplexed signal shown in FIG. 5. The time division multiplexed signal is input to switch group 54. Switch control of switch group 54 and drive of actuator 88 are the same as in embodiment 1.

In the printing device 1 according to the second embodiment, the data value of the drive waveform data Da is read from the memory 55 and input to the first D/A converter 52a to generate an analog signal 60A. The drive waveform data Db is also read from the memory 55 and input to the second D/A converter 52b to generate an analog signal 60B. The data value of the drive waveform data Dc is also read from the memory 55 and input to the third D/A converter 52c to generate an analog signal 60C. The first switch 56a is opened and closed based on the first time division signal S3a indicating the opening and closing timing, the second switch 56b is opened and closed based on the second time division signal S3b indicating the opening and closing timing different from the first time division signal S3a, and the third switch 56c is opened and closed based on the third time division signal S3c indicating the opening and closing timing different from the first and second time division signals S3a and S3b, thereby generating a time division multiplexed signal from each of the analog signals 60A to 60C.

The printer 1 according to the second embodiment may be modified to the following configuration. FIG. 11 is a block diagram of the control device 50 according to the modified example. In the modified example, three amplifiers 53a to 53c are provided instead of the amplifier 53. Also, an analog signal from the first D/A converter 52a is input to the amplifier 53a, and the amplifier 53a outputs an analog signal to the first switch 56a. An analog signal from the second D/A converter 52b is input to the amplifier 53b, and the amplifier 53b outputs an analog signal to the second switch 56b. An analog signal from the third D/A converter 52c is input to the amplifier 53c, and the amplifier 53c outputs an analog signal to the third switch 56c. The first to third switches 56a to 56c are opened and closed based on the first to third time division signals S3a to S3c, and a time division multiplexed signal is generated. In other words, in the time division multiplexed signal, a part of the analog signal 60A output from the amplifier 53a and a part of the analog signal 60B output from the amplifier 53b are continuous, a part of the analog signal 60B output from the amplifier 53b and a part of the analog signal 60C output from the amplifier 53c are continuous, and a part of the analog signal 60C output from the amplifier 53c and a part of the analog signal 60A output from the amplifier 53a are continuous. In other words, in the time division multiplexed signal, between a part of the analog signal 60A output from the amplifier 53a and a part of the analog signal 60B output from the amplifier 53b, there is no analog signal 60C output from the amplifier 53c or other waveforms. Also, in the time division multiplexed signal, between a part of the analog signal 60B output from the amplifier 53b and a part of the analog signal 60C output from the amplifier 53c, there is no analog signal 60A output from the amplifier 53a or other waveforms. In addition, in the time division multiplexed signal, the part of the analog signal 60B output from the amplifier 53b and analog signals with other waveforms are not present between the part of the analog signal 60C output from the amplifier 53c and the part of the analog signal 60A output from the amplifier 53a. By using three amplifiers, the bandwidth of each amplifier can be narrowed, making it easier to realize time division multiplexing.

(Embodiment 3)
The present invention will be described below with reference to the drawings showing a printing device 1 according to a third embodiment of the present invention. Among the components according to the third embodiment, the same components as those in the first or second embodiment are given the same reference numerals, and detailed description thereof will be omitted. Fig. 12 is a block diagram of a control device 50.

The control device 50 includes a control circuit 51, a D/A converter 52, three amplifiers 53d to 53f, a switch group 54, a memory 55, a third switch control section 57, and a sample-and-hold unit 58 (S/H unit). The third switch control section 57 includes a first switch 57a, a second switch 57b, and a third switch 57c. The sample-and-hold unit 58 includes a first sample-and-hold circuit 58a (first S/H circuit), a second sample-and-hold circuit 58b (second S/H circuit), and a third sample-and-hold circuit 58c (third S/H circuit).

The control circuit 51 outputs the time series data to the D/A converter 52. The D/A converter 52 converts the time series data into an analog signal and outputs it to the sample-and-hold unit 58. The analog signal output by the D/A converter 52 is the same as the analog signal shown in FIG. 5.

The control circuit 51 outputs sampling signals S4a to S4c indicating the sampling period to the sample hold unit 58. The sampling signal S4a is input to the first sample hold circuit 58a, the sampling signal S4b is input to the second sample hold circuit 58b, and the sampling signal S4c is input to the third sample hold circuit 58c. The sampling periods of the sampling signals S4a to S4c are different from one another and are shifted by a time interval Δt. The three sampling signals S4a, S4b, and S4c are also simply referred to as sampling signal S4 (see Figure 12).

The first sample-and-hold circuit 58a samples and holds an analog signal at the sampling period of the sampling signal S4a, and outputs it to the amplifier 53d. The second sample-and-hold circuit 58b samples and holds an analog signal at the sampling period of the sampling signal S4b, and outputs it to the amplifier 53e. The third sample-and-hold circuit 58c samples and holds an analog signal at the sampling period of the sampling signal S4c, and outputs it to the amplifier 53f.

The analog signal output by the first sample-and-hold circuit 58a is similar to the analog signal 60A in FIG. 10. The analog signal output by the second sample-and-hold circuit 58b is similar to the analog signal 60B in FIG. 10. The analog signal output by the third sample-and-hold circuit 58c is similar to the analog signal 60C in FIG. 10.

Amplifier 53d amplifies the analog signal and outputs it to the first switch 57a. Amplifier 53e amplifies the analog signal and outputs it to the second switch 57b. Amplifier 53f amplifies the analog signal and outputs it to the third switch 57c.

The control circuit 51 outputs a time division signal S5a corresponding to the analog signal output by the amplifier 53d, a time division signal S5b corresponding to the analog signal output by the amplifier 53e, and a time division signal S5c corresponding to the analog signal output by the amplifier 53f to the third switch control unit 57. The three time division signals S5a, S5b, and S5c are also simply referred to as time division signals S5 (see FIG. 12).

Time division signals S5a, S5b, and S5c are pulse waves similar to the time division signals S3a, S3b, and S3c shown in FIG. 10. A time interval Δt is provided between the rising edge of the pulse of time division signal S5a and the rising edge of the pulse of time division signal S5b. A time interval Δt is also provided between the rising edge of the pulse of time division signal S5b and the rising edge of the pulse of time division signal S5c, and a time interval Δt is provided between the rising edge of the pulse of time division signal S5c and the rising edge of the pulse of time division signal S5a. Each of the time division signals S5a, S5b, and S5c corresponds to each of the synchronization signals S2a, S2b, and S2c described above.

The first switch 57a closes when the pulse of the time division signal S5a is in a high level section and opens when it is in a low level section. The second switch 57b closes when the pulse of the time division signal S5b is in a high level section and opens when it is in a low level section. The third switch 57c closes when the pulse of the time division signal S5c is in a high level section and opens when it is in a low level section. Note that the first switch 57a, the second switch 57b, and the third switch 57c may be open at the same time, but are never closed at the same time. This is because if the first switch 57a, the second switch 57b, and the third switch 57c were closed at the same time, the analog signals 60A, 60B, and 60C would be mixed together. Since the analog signals 60A, 60B, and 60C are not mixed, in the time division multiplexed signal, a part of the analog signal 60A output from the amplifier 53d and a part of the analog signal 60B output from the amplifier 53e are continuous, a part of the analog signal 60B output from the amplifier 53e and a part of the analog signal 60C output from the amplifier 53f are continuous, and a part of the analog signal 60C output from the amplifier 53f and a part of the analog signal 60A output from the amplifier 53d are continuous. In other words, in the time division multiplexed signal, there is no analog signal 60C output from the amplifier 53f or analog signals of other waveforms between a part of the analog signal 60A output from the amplifier 53d and a part of the analog signal 60B output from the amplifier 53e. Also, in the time division multiplexed signal, there is no part of the analog signal 60A output from the amplifier 53d or analog signals of other waveforms between a part of the analog signal 60B output from the amplifier 53e and a part of the analog signal 60C output from the amplifier 53f. Furthermore, in the time division multiplexed signal, there is no part of the analog signal 60B output from the amplifier 53e or analog signals with other waveforms between the part of the analog signal 60C output from the amplifier 53f and the part of the analog signal 60A output from the amplifier 53d.

The third switch control unit 57 outputs a composite signal, i.e., a time division multiplexed signal, which is a composite signal of the analog signals output from the amplifiers 53d to 53f. This time division multiplexed signal is the same as the time division multiplexed signal shown in FIG. 5. The time division multiplexed signal is input to the switch group 54. The switch control of the switch group 54 and the drive of the actuator 88 are the same as in the first embodiment.

The sampling time indicated by sampling signal S4a is earlier than the closing time indicated by time division signal S5a, the sampling time indicated by sampling signal S4b is earlier than the closing time indicated by time division signal S5b, and the sampling time indicated by sampling signal S4c is earlier than the closing time indicated by time division signal S5c.

In the printing device 1 according to the third embodiment, the data values of the drive waveform data Da, Db, and Dc are read from the memory 55, arranged in chronological order, and input to the D/A converter 52. The first sample-and-hold circuit 58a is operated based on the first sampling signal S4a, the second sample-and-hold circuit 58b is operated based on the second sampling signal S4b, and the third sample-and-hold circuit 58c is operated based on the third sampling signal S4c. The first to third switches 57a to 57c are opened and closed based on the time-division signals S5a to S5c, and a time-division multiplexed signal can be generated.

The sampling time indicated by sampling signal S4a is earlier than the closing time indicated by time-division signal S5a, the sampling time indicated by sampling signal S4b is earlier than the closing time indicated by time-division signal S5b, and the sampling time indicated by sampling signal S4c is earlier than the closing time indicated by time-division signal S5c. Therefore, the effect of delays in time-division signals S5a to S5c on the generation of the time-division multiplexed signal can be suppressed.

(Embodiment 4)
The present invention will be described below with reference to the drawings showing a printing device 1 according to a fourth embodiment of the present invention. Among the components according to the fourth embodiment, the same components as those in the first to third embodiments are given the same reference numerals, and detailed description thereof will be omitted. Fig. 13 is a block diagram of a control device 50.

The control device 50 includes a control circuit 51, a digital amplifier 530 to which digital data can be directly input, a low-pass filter 59 (LPF), a group of switches 54, and a memory 55. The digital amplifier 530 includes a switching circuit and an amplifier circuit. The control circuit 51 outputs time series data (digital data) to the digital amplifier 530, and the digital amplifier 530 amplifies the time series data and outputs it to the low-pass filter 59. In other words, in the time division multiplexed signal, the quantized data A0 and the quantized data B0 are continuous, the quantized data B0 and the quantized data C0 are continuous, and the quantized data C0 and the quantized data A1 are continuous. That is, in the time division multiplexed signal, there is no quantized data C0, other quantized data, or data of other waveforms between the quantized data A0 and the quantized data B0. In addition, there is no quantized data A0, other quantized data, or data of other waveforms between the quantized data B0 and the quantized data C0 in the time division multiplexed signal. Furthermore, in the time division multiplexed signal, there is no quantized data B0, other quantized data, or data of other waveforms between the quantized data C0 and the quantized data A0. The low pass filter 59 converts the pulse wave output from the digital amplifier 530 into an analog signal, and outputs the time division multiplexed signal composed of the analog signal to the switch group 54. The switch control of the switch group 54 and the drive of the actuator 88 are the same as in the first embodiment. Note that the output of the digital amplifier 530 is not an analog signal, since it is a pulse-like shape and not a continuous waveform. In other words, the output of the digital amplifier 530 is a time division multiplexed signal composed of a digital signal.

In the printing device according to the fourth embodiment, the data values of each of the drive waveform data Da, Db, and Dc can be read from the memory 55 and input to the digital amplifier 530 to generate a time division multiplexed signal. By using the digital amplifier 530, the D/A converter can be eliminated. Compared to an analog amplifier, the digital amplifier 530 does not require highly accurate and stable parts, so it is more resistant to environmental changes such as temperature changes, and has a longer life because it requires fewer operations and fewer parts.

(Embodiment 5)
The present invention will be described below with reference to the drawings showing a printing device 1 according to a fifth embodiment of the present invention. Among the components according to the fifth embodiment, the same components as those in the first to fourth embodiments are given the same reference numerals, and detailed description thereof will be omitted. FIG 14 is a block diagram of a control device 50.

The control device 50 includes a control circuit 51, a D/A converter 52, an amplifier 53, an amplitude information generating circuit 70, a voltage determination circuit 71, a voltage variable power supply 72, etc. The control circuit 51 accesses the memory 55 to acquire the drive waveform data Da to Dc, and outputs it to the D/A converter 52. The D/A converter 52 converts the drive waveform data Da to Dc into an analog signal and outputs it to the amplifier 53. The signal control from the amplifier 53 to the actuator 88 is omitted as it is the same as in the first to fourth embodiments.

The control circuit 51 outputs a digital signal to the amplitude information generating circuit 70, which generates information indicating the amplitude of the digital signal and outputs it to the voltage determination circuit 71. The voltage determination circuit 71 determines the voltage to be set in the amplifier 53 based on the information indicating the amplitude, and outputs it to the voltage variable power supply 72. The voltage variable power supply 72 supplies the determined voltage to the amplifier 53. Note that the determined voltage is lower than the maximum voltage that the voltage variable power supply 72 can supply.

Figure 15 is an explanatory diagram illustrating the relationship between the analog signal output from the D/A converter 52 and the voltage supplied to the amplifier 53. In Figure 15, the dashed line indicates the voltage supplied to the amplifier 53. As shown in Figure 15, a voltage of a magnitude corresponding to the amplitude of the analog signal is supplied to the amplifier 53. Power consumption can be reduced compared to when the maximum voltage that the voltage variable power supply 72 can supply is supplied to the amplifier 53.

Although the above-mentioned printing device 1 is a serial head type, the above-mentioned technology may be applied to a line head type printing device. In addition, although the above-mentioned printing device 1 is equipped with a piezoelectric type inkjet head, the above-mentioned technology may be applied to a printing device equipped with an ink heating type inkjet type inkjet head or an electrostatic force type inkjet head. In particular, when the above-mentioned technology is applied to a printing device equipped with an ink heating type inkjet type head, in the first embodiment, the driving waveforms A, B, and C have different amplitudes and pulse widths, but the amplitudes are about the same and the pulse widths are different. Note that an electrostatic force type inkjet head is, for example, configured by stacking a first substrate, a second substrate, and a third substrate made of a silicon single crystal substrate. The first substrate has a recess that forms a liquid chamber with the bottom wall as a vibration plate. The second substrate is bonded to the first substrate and has an electrode of approximately the same shape as the vibration plate. The third substrate is bonded to the first substrate and has a part of the liquid chamber, a nozzle, and a flow path connecting the liquid chamber and the nozzle. When a positive pulse voltage is applied to the electrode from the oscillator circuit, the surface of the electrode is charged to a positive potential, and the corresponding diaphragm is charged to a negative potential. The diaphragm then bends and the liquid chamber expands. When the application of the pulse voltage to the electrode is then turned off, the bent diaphragm returns to its original position, the liquid chamber shrinks, the pressure in the liquid chamber increases, and ink is ejected from the nozzle. The first, second, and third substrates may be made of not only silicon, but also glass, nickel, plastic, and stainless steel.

In the first embodiment, the resonant frequency of the inkjet head 8 is the resonant frequency when the pressure chamber 81 is not filled with ink, or the resonant frequency when the pressure chamber 81 is filled with ink, but is not limited to these. The resonant frequency of the inkjet head 8 may be higher than the resonant frequency when the pressure chamber 81 is filled with ink, and lower than the resonant frequency when the pressure chamber 81 is not filled with ink.

In the first embodiment, the time series data is data Ak, Bk, and Ck arranged in order with a time interval Δt, in the order of A0, B0, C0, A1, B1, C1, ..., Ak, Bk, and Ck. However, various improvements are possible for the data Ak, Bk, and Ck. For example, when the time interval Δt is set to a shorter time interval Δt', the control circuit 51 generates data A'k, B'k, and C'k by thinning out a part of the high level section and the low level section, excluding the rising and falling parts, for the data Ak, Bk, and Ck. In other words, the time length of the data A'k is shorter than the time length of the data Ak. Also, the time length of the data B'k is shorter than the time length of the data Bk. Also, the time length of the data C'k is shorter than the time length of the data Ck. The control circuit 51 may treat the data A'0, B'0, C'0, A'1, B'1, C'1, ..., A'k, B'k, and C'k in this order as time series data.

When the time interval Δt is set to a longer time interval Δt", the control circuit 51 generates data A"k, B"k, and C"k by extending the high level and low level sections of the data Ak, Bk, and Ck, excluding the rising and falling edges. In other words, the time length of data A"k is longer than the time length of data Ak. The time length of data B"k is longer than the time length of data Bk. The time length of data C"k is longer than the time length of data Ck. The control circuit 51 may arrange data A"0, B"0, C"0, A"1, B"1, C"1, ..., A"k, B"k, and C"k in this order as time series data.

In the first embodiment, the control circuit 51 accesses the memory 55 to obtain the drive waveform data Da, Db, and Dc, and creates the time series data. The time series data is the data Ak, Bk, and Ck arranged in order with a time interval Δt provided, but is not limited to this. The control circuit 51 may access the memory 55 to obtain the drive waveform data Da, Db, and Dc, and create the time series data by thinning out a part of the obtained drive waveform data Da, Db, and Dc. Specifically, the drive waveform data Da has quantized data A0, A1, A2, and A3, the drive waveform data Db has quantized data B0, B1, B2, and B3, and the drive waveform data Dc has quantized data C0, C1, C2, and C3, but the data arranged in the order of A0, B0, C0, A2, B2, C2, ..., Ak, Bk, and Ck using the quantized data A0, A2, B0, B2, C0, and C2 may be used as the time series data.

In addition, using the quantized data A0, A2, B1, B3, C0, and C2, data arranged in the order A0, C0, B1, A2, C2, B2, ..., Ak-1, Ck-1, and Bk may be used as time-series data.In addition, using the quantized data A1, A3, B0, B2, C1, and C3, data arranged in the order B0, A1, C1, B2, A3, C3, ..., Bk-1, Ak, and Ck may be used as time-series data.

In addition, the control circuit 51 may access the memory 55 to acquire the drive waveform data Da, Db, and Dc, generate interpolation data based on the acquired drive waveform data Da, Db, and Dc, and create time series data using the acquired drive waveform data Da, Db, and Dc and the interpolation data. Specifically, the drive waveform data Da has quantized data A0, A1, A2, and A3, the drive waveform data Db has quantized data B0, B1, B2, and B3, and the drive waveform data Dc has quantized data C0, C1, C2, and C3. The control circuit 51 also generates interpolated data A0.5 based on the quantized data A0 and A1, generates interpolated data A1.5 based on the quantized data A1 and A2, generates interpolated data B0.5 based on the quantized data B0 and B1, generates interpolated data B1.5 based on the quantized data B1 and B2, generates interpolated data C0.5 based on the quantized data C0 and C1, and generates interpolated data C1.5 based on the quantized data C1 and C2. The control circuit 51 may also use data arranged in the order of quantized data A0, B0, C0, interpolated data A0.5, B0.5, C0.5, quantized data A1, B1, C1, interpolated data A1.5, B1.5, C1.5, quantized data A2, B2, C2, ..., Ak, Bk, Ck as time series data.

Furthermore, the control circuit 51 generates interpolated data A0.25 based on the quantized data A0 and the interpolated data A0.5, generates interpolated data A0.75 based on the interpolated data A0.5 and the quantized data A1, generates interpolated data B0.25 based on the quantized data B0 and the interpolated data B0.5, generates interpolated data B0.75 based on the interpolated data B0.5 and the quantized data B1, generates interpolated data C0.25 based on the quantized data C0 and the interpolated data C0.5, and generates interpolated data C0.75 based on the interpolated data C0.5 and the quantized data C1. The control circuit 51 may treat the data arranged in the order of quantized data A0, B0, C0, interpolated data A0.25, B0.25, C0.25, interpolated data A0.5, B0.5, C0.5, interpolated data A0.75, B0.75, C0.75, quantized data A1, B1, C1, ..., Ak, Bk, Ck as time series data. The memory 55 may store the interpolated data A0.5, A1.5, B0.5, B1.5, C0.5, C1.5 in advance. The memory 55 may also store the interpolated data A0.25, A0.75, B0.25, B0.75, C0.25, C0.75 in advance.

In the first embodiment, the drive waveform A is a waveform for ejecting a large drop, the drive waveform B is a waveform for ejecting a medium drop, and the drive waveform C is a waveform for ejecting a large drop. However, this is not limited to this. The drive waveform C may be a waveform for ejecting a small drop. Also, there may be a drive waveform D. The drive waveform D is a waveform for ejecting an ink drop larger than a large drop. In other words, the drive waveform is not limited to three types, and may be four types or two types. When there are four types of drive waveforms, the type of analog signal does not change in one print task, and the time division multiplexed signal is composed of four types of analog signals. Even in one cycle from when the time division multiplexed signal rises to when it falls within one ejection drive period, the type of analog signal does not change, and the time division multiplexed signal is composed of four types of analog signals. Also, when there are two types of drive waveforms, the type of analog signal does not change in one print task, and the time division multiplexed signal is composed of two types of analog signals. Even during one cycle from when the time division multiplexed signal rises to when it falls within one ejection drive period, the type of analog signal does not change, and the time division multiplexed signal is composed of two types of analog signals.

In the first embodiment, the driving waveforms A, B, and C are used for printing. However, this is not limiting. The driving waveforms A, B, and C may be used for flushing processing (S7). In other words, the time division multiplexed signal includes three types of driving waveforms that eject ink through the nozzle 80 for the flushing processing (S7). Then, the driving waveform signal Pa, the driving waveform signal Pb, and the driving waveform signal Pc are separated from the time division multiplexed signal by a predetermined sampling frequency. Then, the actuator 88 is driven by any one of the driving waveform signal Pa, the driving waveform signal Pb, and the driving waveform signal Pc. The printing device 1 can eject ink for three types of flushing processing (S7) with only one type of time division multiplexed signal, for example. In this case, the ink ejection for the three flushing processes (S7) includes a first flushing process in which a predetermined number of ink droplets are ejected, a second flushing process in which a greater number of ink droplets are ejected than in the first flushing process, and a third flushing process in which a greater number of ink droplets are ejected than in the second flushing process. Note that the ink ejection for the three flushing processes (S7) may have the same number of ink droplets ejected but different ink droplet sizes. In the second flushing process, the ink droplet size is larger than in the first flushing process. Also, in the third flushing process, the ink droplet size is larger than in the second flushing process.

In the first embodiment, the driving waveforms A, B, and C are waveforms for deforming the piezoelectric body 83, vibrating the vibration plate 82, and discharging the ink in the pressure chamber 81 through the nozzle 80 after passing through the descender by the vibration of the vibration plate 82. However, this is not limited to this. For example, the driving waveforms A and B are waveforms for discharging the ink in the pressure chamber 81 through the nozzle 80 after passing through the descender, but the driving waveform C is not necessarily a waveform for discharging the ink in the pressure chamber 81 through the nozzle 80 after passing through the descender by the vibration of the vibration plate 82. In other words, the driving waveform C is a waveform for a non-ejection flushing process, and in detail, the piezoelectric body 83 is slightly deformed. Then, the surface (meniscus) of the ink vibrates without discharging the ink. Therefore, the time division multiplexed signal includes two types of driving waveforms for discharging the ink through the nozzle 80 and one type of driving waveform for vibrating the surface (meniscus) of the ink without discharging the ink. Then, the drive waveform signal Pa, the drive waveform signal Pb, and the drive waveform signal Pc are separated from the time division multiplexed signal by a predetermined sampling frequency. Then, the actuator 88 is driven by any one of the drive waveform signal Pa, the drive waveform signal Pb, and the drive waveform signal Pc. For example, the printing device 1 can perform two types of ink ejection and one type of ink surface (meniscus) vibration with only one type of time division multiplexed signal. Also, for example, the printing device 1 can perform ink ejection for two types of flushing processes (S7) and one type of ink surface (meniscus) vibration for the non-ejection waveform flushing process (S10) with only one type of time division multiplexed signal. In this case, the ink ejection for the two types of flushing processes (S7) includes a first flushing process in which the number of ink droplets is a predetermined number, and a second flushing process in which the number of ink droplets is greater than that of the first flushing process. The ink ejection for the two flushing processes (S7) may be the same in number but different in size. The ink droplets ejected in the second flushing process are larger in size than those ejected in the first flushing process.

Also, for example, the driving waveform A is a waveform for ejecting the ink in the pressure chamber 81 through the nozzle 80 after passing through the descender, while the driving waveforms B and C are waveforms for non-ejection flushing processing, and in detail, the piezoelectric body 83 is slightly deformed. Then, the ink surface (meniscus) vibrates without ejecting the ink. Therefore, the time division multiplexed signal includes one type of driving waveform for ejecting the ink through the nozzle 80 and two types of driving waveform for vibrating the ink surface (meniscus) without ejecting the ink. After that, the driving waveform signal Pa, the driving waveform signal Pb, and the driving waveform signal Pc are separated from the time division multiplexed signal by a predetermined sampling frequency. The actuator 88 is driven by any one of the driving waveform signal Pa, the driving waveform signal Pb, and the driving waveform signal Pc. The printing device 1 can eject ink in one way and vibrate the ink surface (meniscus) in two ways with only one type of time division multiplexed signal. For example, the printing device 1 can perform one type of ink ejection, an ink surface (meniscus) vibration to suppress thickening of the ink near the nozzle, and an ink surface (meniscus) vibration to keep the temperature of the ink near the nozzle constant, using only one type of time division multiplexed signal. Also, for example, the printing device 1 can perform ink ejection for one type of flushing process (S7) and two types of ink surface (meniscus) vibration for the non-ejection waveform flushing process (S10) using only one type of time division multiplexed signal. In this case, the ink surface (meniscus) vibration for the two types of non-ejection flushing processes (S10) includes a first non-ejection flushing process in which the surface (meniscus) is vibrated a predetermined number of times, and a second non-ejection flushing process in which the surface (meniscus) is vibrated more times than the first non-ejection flushing process. The ink surface (meniscus) may be vibrated for the two non-ejection flushing processes (S10) the same number of times, but with different strengths of the surface (meniscus) vibration. In the second non-ejection flushing process, the surface (meniscus) vibration is stronger than in the first non-ejection flushing process.

Also, for example, the drive waveforms A, B, and C are waveforms for a non-ejection flushing process, and in detail, the piezoelectric body 83 is slightly deformed. Then, the ink surface (meniscus) vibrates without ejecting ink. Therefore, the time division multiplexed signal includes three types of drive waveforms that vibrate the ink surface (meniscus) without ejecting ink. Then, the drive waveform signal Pa, the drive waveform signal Pb, and the drive waveform signal Pc are separated from the time division multiplexed signal by a predetermined sampling frequency. The actuator 88 is driven by any one of the drive waveform signal Pa, the drive waveform signal Pb, and the drive waveform signal Pc. In other words, the printing device 1 can vibrate the ink surface (meniscus) in three ways. For example, using three types of time division multiplexed signals, the printing device 1 can vibrate the ink surface (meniscus) to suppress mild thickening of the ink near the nozzle, vibrate the ink surface (meniscus) more greatly to suppress severe thickening of the ink near the nozzle, and vibrate the ink surface (meniscus) to keep the temperature of the ink constant near the nozzle.

The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The technical features described in each embodiment can be combined with each other, and the scope of the present invention is intended to include all modifications within the scope of the claims and equivalents to the scope of the claims.

REFERENCE SIGNS LIST 1 Printing device 50 Control device 51 Control circuit 52 D/A converter 53 Amplifier 530 Digital amplifier 54 Switch group 55 Memory 56 Second switch control section 57 Third switch control section 58 Sample hold unit 70 Amplitude information generating circuit 71 Voltage determination circuit 72 Variable voltage power supply

Claims (14)

A nozzle that ejects liquid by an energy imparting element;
a multiplexing unit that generates a time division multiplexed signal capable of transmitting the first data and the second data on a single signal line, the first data and the second data being arranged based on at least first data indicating a first drive waveform and second data indicating a second drive waveform different from the first drive waveform such that a third portion that is a part of the second drive waveform is between a first portion that is a part of the first drive waveform and a second portion that is a part of the first drive waveform, and the second portion is between the third portion and a fourth portion that is a part of the second drive waveform;
a separation unit that separates a first drive waveform signal indicating the first drive waveform or a second drive waveform signal indicating the second drive waveform from the time division multiplexed signal generated by the multiplexing unit,
the energy application element is driven by the first driving waveform signal or the second driving waveform signal separated by the separation unit ;
the first data and the second data each have a plurality of quantized data values;
the multiplexing unit includes a control circuit, a D/A converter that converts the data values of the first data and the second data into analog signals, an amplifier that amplifies the analog signals of the D/A converter, and a memory that stores the first data and the second data;
the control circuit reads out the data values of the first data and the second data from the memory, arranges them in a time series, transmits them, and generates the time division multiplexed signal;
the control circuit inputs the data values of the first data and the second data to the D/A converter;
The D/A converter outputs the analog signal to the amplifier.
The amplifier outputs the analog signal to the separator,
The separation section separates the analog signal amplified by the amplification section into the first driving waveform signal or the second driving waveform signal . A nozzle that ejects liquid by an energy imparting element;
a multiplexing unit that generates a time division multiplexed signal capable of transmitting the first data and the second data on a single signal line, the first data and the second data being arranged based on at least first data indicating a first drive waveform and second data indicating a second drive waveform different from the first drive waveform such that a third portion that is a part of the second drive waveform is between a first portion that is a part of the first drive waveform and a second portion that is a part of the first drive waveform, and the second portion is between the third portion and a fourth portion that is a part of the second drive waveform;
a separation unit that separates a first drive waveform signal indicating the first drive waveform or a second drive waveform signal indicating the second drive waveform from the time division multiplexed signal generated by the multiplexing unit;
Equipped with
the energy application element is driven by the first driving waveform signal or the second driving waveform signal separated by the separation unit;
the first data and the second data each have a plurality of quantized data values;
the multiplexing unit includes a control circuit, a memory that stores the first data and the second data, and a digital amplifier that can directly input digital data;
The control circuit reads out the data values of the first data and the second data from the memory, arranges them in a time series, and outputs the data values of the first data and the second data to the digital amplifier.
head . A nozzle that ejects liquid by an energy imparting element;
a multiplexing unit that generates a time division multiplexed signal capable of transmitting the first data and the second data on a single signal line, the first data and the second data being arranged based on at least first data indicating a first drive waveform and second data indicating a second drive waveform different from the first drive waveform such that a third portion that is a part of the second drive waveform is between a first portion that is a part of the first drive waveform and a second portion that is a part of the first drive waveform, and the second portion is between the third portion and a fourth portion that is a part of the second drive waveform;
a separation unit that separates a first drive waveform signal indicating the first drive waveform or a second drive waveform signal indicating the second drive waveform from the time division multiplexed signal generated by the multiplexing unit;
Equipped with
the energy application element is driven by the first driving waveform signal or the second driving waveform signal separated by the separation unit;
the first data and the second data each have a plurality of quantized data values;
The multiplexing unit
A control circuit;
a memory that stores the first data and the second data;
a first D/A converter for converting a data value of the first data into an analog signal;
a first switch to which the analog signal from the first D/A converter is input;
a second D/A converter for converting the data value of the second data into an analog signal;
a second switch to which the analog signal from the second D/A converter is input;
The control circuit reads the data value of the first data from the memory and inputs it to the first D/A converter, reads the data value of the second data from the memory and inputs it to the second D/A converter, opens and closes the first switch based on a first time division signal indicating an opening and closing timing, and opens and closes the second switch based on a second time division signal indicating an opening and closing timing different from the first time division signal, thereby generating the time division multiplexed signal.
head . A nozzle that ejects liquid by an energy imparting element;
a multiplexing unit that generates a time division multiplexed signal capable of transmitting the first data and the second data on a single signal line, the first data and the second data being arranged based on at least first data indicating a first drive waveform and second data indicating a second drive waveform different from the first drive waveform such that a third portion that is a part of the second drive waveform is between a first portion that is a part of the first drive waveform and a second portion that is a part of the first drive waveform, and the second portion is between the third portion and a fourth portion that is a part of the second drive waveform;
a separation unit that separates a first drive waveform signal indicating the first drive waveform or a second drive waveform signal indicating the second drive waveform from the time division multiplexed signal generated by the multiplexing unit;
Equipped with
the energy application element is driven by the first driving waveform signal or the second driving waveform signal separated by the separation unit;
the first data and the second data each have a plurality of quantized data values;
The multiplexing unit
A control circuit;
a memory that stores the first data and the second data;
a first D/A converter for converting a data value of each of the first data and the second data into an analog signal;
a first sample-and-hold circuit and a second sample-and-hold circuit for sampling and holding an analog signal from the first D/A converter;
a first amplifier section that amplifies an analog signal from the first sample-and-hold circuit;
a second amplifier section that amplifies the analog signal of the second sample-and-hold circuit;
a first switch to which the analog signal of the first amplifier is input;
a second switch to which the analog signal of the second amplifier unit is input,
the control circuit reads out the data values of the first data and the second data from the memory, arranges them in a time series, and inputs them to the first D/A converter, operates the first sample-and-hold circuit based on a first sampling signal indicating a sampling period, operates the second sample-and-hold circuit based on a second sampling signal indicating a sampling period different from the first sampling signal, opens and closes the first switch based on a first time-division signal indicating an opening point and a closing point of the first switch, and opens and closes the second switch based on a second time-division signal indicating an opening point and a closing point of the second switch different from the first time - division signal, thereby generating the time-division multiplexed signal.
head . The head of claim 4 , wherein the sampling time indicated by the first sampling signal is earlier than the closing time indicated by the first time division signal, and the sampling time indicated by the second sampling signal is earlier than the closing time indicated by the second time division signal. A nozzle that ejects liquid by an energy imparting element;
a multiplexing unit that generates a time division multiplexed signal capable of transmitting the first data and the second data on a single signal line, the first data and the second data being arranged based on at least first data indicating a first drive waveform and second data indicating a second drive waveform different from the first drive waveform such that a third portion that is a part of the second drive waveform is between a first portion that is a part of the first drive waveform and a second portion that is a part of the first drive waveform, and the second portion is between the third portion and a fourth portion that is a part of the second drive waveform;
a separation unit that separates a first drive waveform signal indicating the first drive waveform or a second drive waveform signal indicating the second drive waveform from the time division multiplexed signal generated by the multiplexing unit;
Equipped with
the energy applying element is a head driven by the first driving waveform signal or the second driving waveform signal separated by the separation unit,
The separation unit separates the first driving waveform signal or the second driving waveform signal using a sampling frequency equal to or higher than a resonance frequency of the head.
head . a pressure chamber that applies pressure to eject liquid from the nozzle by driving the energy applying element;
The head according to claim 6 , wherein the resonant frequency of the head is a resonant frequency when the pressure chamber is filled with liquid. a pressure chamber that applies pressure to eject liquid from the nozzle by driving the energy applying element;
The head according to claim 6 , wherein the resonant frequency of the head is a resonant frequency when the pressure chamber is not filled with liquid. the demultiplexer includes a switch to which the time division multiplexed signal is input,
A switch control signal for opening and closing the switch and a synchronization signal indicating the opening and closing timing are input to the switch ,
7. The head according to claim 1, wherein the switch opens and closes based on the switch control signal and the synchronization signal to separate the first driving waveform signal or the second driving waveform signal from the time division multiplexed signal. A control circuit is provided,
The head of claim 9 , wherein the control circuit opens and closes the switch based on the switch control signal and the synchronization signal. the first data and the second data each have a plurality of quantized data values;
The multiplexing unit
an amplifier section for amplifying the time division multiplexed signal;
an amplitude information generating circuit for generating amplitude information of the time division multiplexed signal;
a voltage variable power supply that supplies a voltage to the amplifier; and a determination circuit that determines a supply voltage, the supply voltage being a voltage whose value varies based on the generated amplitude information and which is lower than a maximum voltage that the voltage variable power supply can supply.
Equipped with
7. The head according to claim 1, wherein the voltage variable power supply supplies the determined supply voltage to the amplifier . The head described in any one of claims 1 to 4 and 6, wherein the multiplexing unit generates the time division multiplexed signal capable of transmitting the first data and the second data over a single signal line, the time division multiplexed signal being arranged such that, after thinning out at least a portion of the first portion, the third portion is between the first portion and the second portion , and the second portion is between the third portion and the fourth portion . The head described in any one of claims 1 to 4 and 6, wherein the multiplexing unit is arranged such that after extending at least the first portion, the third portion is between the first portion and the second portion, and the second portion is between the third portion and the fourth portion, and generates the time division multiplexed signal capable of transmitting the first data and the second data over a single signal line. a multiplexing unit that generates a time division multiplexed signal capable of transmitting the first data and the second data on a single signal line, the first data and the second data being arranged based on at least first data indicating a first drive waveform and second data indicating a second drive waveform different from the first drive waveform such that a third portion that is a part of the second drive waveform is between a first portion that is a part of the first drive waveform and a second portion that is a part of the first drive waveform, and the second portion is between the third portion and a fourth portion that is a part of the second drive waveform;
a separation unit that separates a first drive waveform signal indicating the first drive waveform or a second drive waveform signal indicating the second drive waveform from the time division multiplexed signal generated by the multiplexing unit;
an energy imparting element driven by the first driving waveform signal or the second driving waveform signal separated by the separation unit;
a nozzle that ejects liquid by driving the energy imparting element ;
the first data and the second data each have a plurality of quantized data values;
the multiplexing unit includes a control circuit, a D/A converter that converts the data values of the first data and the second data into analog signals, an amplifier that amplifies the analog signals of the D/A converter, and a memory that stores the first data and the second data;
the control circuit reads out the data values of the first data and the second data from the memory, arranges them in a time series, transmits them, and generates the time division multiplexed signal;
the control circuit inputs the data values of the first data and the second data to the D/A converter;
The D/A converter outputs the analog signal to the amplifier.
The amplifier outputs the analog signal to the separator,
a head, wherein the separation unit separates the analog signal amplified by the amplification unit into the first driving waveform signal or the second driving waveform signal ;
a transport unit that transports a print medium on which printing is performed by the liquid ejected from the nozzles.

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