Head and printing apparatus

Abstract

The present invention relates to a head and a printing apparatus. A head and a printing apparatus are provided which enable to reduce a wait time of a nozzle by adjusting an amplitude of a drive waveform applied to an energy applying element. A head includes: a nozzle configured to discharge a liquid by an energy applying element; a multiplexer configured to generate a time division multiplexed signal based on at least first data representing a first drive waveform and second data representing a second drive waveform different from the first drive waveform, the time division multiplexed signal being transmittable by a single signal line; and a separator configured to separate out, from the time division multiplexed signal generated by the multiplexer, either a first drive waveform signal representing the first drive waveform or a second drive waveform signal representing the second drive waveform; wherein the energy applying element is configured to be driven by either the first drive waveform signal or the second drive waveform signal separated out by the separator.

Description

Technical Field

[0001] This technology relates to a head for discharging liquids and a printing device. Background Technology

[0002] A printer is known that generates first to fourth drive pulses with different amplitudes as drive signals for driving piezoelectric elements of the nozzles. The first to fourth drive pulses are generated continuously during one cycle for printing one pixel. One of the first to fourth drive pulses is selected and applied to the piezoelectric element in each of the nozzles. The nozzle ejects ink in an amount corresponding to the amplitude of the selected drive pulse to form a dot with a desired size (see Patent Document 1).

[0003] Reference List

[0004] Patent documents

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2010-142978 Summary of the Invention

[0006] Technical issues

[0007] 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 is the nozzle's waiting time.

[0008] This disclosure has been made with the foregoing consideration in mind, with the aim of providing a head and printing device that enables the reduction of nozzle wait time by adjusting the amplitude of the drive waveform applied to the energy application (energy generation) element.

[0009] Solution to the problem

[0010] A head according to one aspect of this disclosure includes: a nozzle configured to discharge liquid through an energy applying element; a multiplexer configured to generate a time-division multiplexed signal based at least on first data representing a first drive waveform and second data representing a second drive waveform different from the first drive waveform, wherein a third portion of the time-division multiplexed signal, being part of the second drive waveform, is arranged between a first portion of the first drive waveform and a second portion of the first drive waveform, and the second portion is arranged between the third portion and a fourth portion of the second drive waveform, the time-division multiplexed signal being capable of transmitting the first and second data via a single signal line; and a separator configured to separate either the first drive waveform signal representing the first drive waveform or the second drive waveform signal representing the second drive waveform from the time-division multiplexed signal generated by the multiplexer. The energy applying element is configured to be driven by either the first drive waveform signal or the second drive waveform signal separated by the separator.

[0011] A printing apparatus according to another aspect of this disclosure includes a head and a transmitter. The head includes: a multiplexer configured to generate a time-division multiplexed signal based at least on first data representing a first drive waveform and second data representing a second drive waveform different from the first drive waveform, wherein a third portion of the time-division multiplexed signal, being part of the second drive waveform, is arranged between a first portion of the first drive waveform and a second portion of the first drive waveform, and the second portion is arranged between the third portion and a fourth portion of the second drive waveform, the time-division multiplexed signal being capable of transmitting the first and second data via a single signal line; a separator configured to separate either a first drive waveform signal representing the first drive waveform or a second drive waveform signal representing the second drive waveform from the time-division multiplexed signal generated by the multiplexer; an energy application element configured to be driven by either the first drive waveform signal or the second drive waveform signal separated by the separator; and a nozzle configured to discharge liquid by the drive of the energy application element. The conveyor is configured to convey printing media that undergoes printing using liquid discharged from the nozzle.

[0012] Advantages of the present invention

[0013] In the head and printing apparatus according to aspects of this disclosure, a time-division multiplexed signal is generated based on first data representing a first drive waveform and second data representing a second drive waveform different from the first drive waveform. In the time-division multiplexed signal, a third portion, as part of the second drive waveform, exists between a first portion, as part of the first drive waveform, and a second portion, as part of the first drive waveform; and a second portion exists between the third portion and a fourth portion, as part of the second drive waveform. A first drive waveform signal representing the first drive waveform or a second drive waveform signal representing the second drive waveform is separated from the generated time-division multiplexed signal. An energy application element is driven by either the first drive waveform signal or the second drive waveform signal. The amplitude of the drive waveform applied to the energy application element can be adjusted by selecting either the first drive waveform signal or the second drive waveform signal. Furthermore, only the period of either selected drive waveform is included in one cycle for printing one pixel, while any period of any unselected drive waveform is not included. Therefore, nozzle wait time can be reduced. Attached Figure Description

[0014] Figure 1 This is a schematic plan view of a printing apparatus according to a first embodiment.

[0015] Figure 2 It is a schematic diagram of a partially enlarged cross-sectional view of the inkjet head.

[0016] Figure 3 This is a block diagram of the controller.

[0017] Figure 4 It is an explanatory drawing used to explain examples of driving waveforms A, B, and C.

[0018] Figure 5 These are explanatory plots used to interpret examples of time-series data, analog signals, and time-division multiplexed signals.

[0019] Figure 6 It is an interpretive plot used to explain the relationship between time-division multiplexed signals and synchronization signals.

[0020] Figure 7 This is a schematic drawing of the drive waveform input to the actuator by turning the nth switch on and off.

[0021] Figure 8 This is a flowchart used to explain the printing process performed by the controller.

[0022] Figure 9 This is a block diagram of the controller according to the second embodiment.

[0023] Figure 10It is an interpretive plot used to explain the relationship between analog signals and time-division signals.

[0024] Figure 11 This is a block diagram of a controller according to a variant embodiment.

[0025] Figure 12 This is a block diagram of the controller according to the third embodiment.

[0026] Figure 13 This is a block diagram of the controller according to the fourth embodiment.

[0027] Figure 14 This is a block diagram of the controller according to the fifth embodiment.

[0028] Figure 15 It is an interpretive plot used to explain the relationship between the analog signal output from the D / A converter and the voltage supplied to the amplifier. Detailed Implementation

[0029] (First Embodiment)

[0030] The invention will now be explained based on drawings to depict a printing apparatus according to a first embodiment. Figure 1 This is a schematic plan view illustrating the printing equipment. In the following explanation, the term "in" will be used... Figure 1 The diagram depicts front, back, left, and right. The front-back direction corresponds to the transport direction, and the left-right direction corresponds to the scan direction. Additionally, the up-down direction is used in the following explanations. Figure 1 The surface side corresponds to the upper side, and the bottom side corresponds to the lower side.

[0031] As in Figure 1 As depicted, the printing apparatus 1 includes, for example, a platform 2, an ink dispensing device 3, and transport rollers 4 and 5. Recording paper 200, serving as the recording medium, is placed on the upper surface of the platform 2. The ink dispensing device 3 records images by dispensing ink onto the recording paper 200 placed on the platform 2. The ink dispensing device 3 includes, for example, a carrier 6, a subtank 7, four inkjet heads 8, and a circulation pump (not depicted).

[0032] Two guide rails 11 and 12, extending in the left-right direction and guiding the carrier 6, are disposed on or above the stage 2. An endless belt 13 extending in the left-right direction is connected to the carrier 6. The endless belt 13 is driven by the carrier drive motor 14. Driven by the endless belt 13, the carrier 6 reciprocates in the scanning direction in the area opposite to the stage 2 while being guided by the guide rails 11 and 12. More specifically, in the state where the carrier 6 supports four inkjet heads 8, the carrier 6 performs a first movement in which the heads move from one position to another from left to right in the scanning direction, and a second movement in which the heads move from one position to another from right to left in the scanning direction.

[0033] Cap 20 and flashing receiver 21 are disposed between guide rails 11 and 12. Cap 20 and flashing receiver 21 are positioned below or beneath ink discharge device 3. Cap 20 is positioned at the right end of guide rails 11 and 12, and flashing receiver 21 is positioned at the left end of guide rails 11 and 12. Note that cap 20 and flashing receiver 21 can be arranged in a left-right inverted manner. (That is, their positions can be interchanged.)

[0034] The auxiliary ink cartridge 7 and four inkjet heads 8 are carried on the carrier 6, and they reciprocate together with the carrier 6 in the scanning direction. The auxiliary ink cartridge 7 is connected to the cartridge holder 15 via a tube 17. One or more ink cartridges 16 of one or more colors (four colors in this embodiment) are mounted to the cartridge holder 15. The four colors are exemplified, for example, by black, yellow, cyan, and magenta.

[0035] Four ink chambers (not depicted) are formed inside the sub-tank 7. The four colored inks supplied from the four ink cartridges 16 are stored separately in the four ink chambers.

[0036] Four inkjet heads 8 are arranged in the scanning direction on the underside of the auxiliary tank 7. Multiple nozzles 80 (see...) Figure 2 A color ink is formed on the lower surface of each of the inkjet heads 8. Each inkjet head 8 corresponds to one color ink and is connected to one ink chamber. That is, four inkjet heads 8 correspond to four color inks respectively and are connected to four ink chambers respectively.

[0037] 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 of the auxiliary tank 7, for example, via pipes. A circulation pump is located between the ink supply port and the ink chamber.

[0038] Ink fed from the ink chamber by a circulation pump flows into the inkjet head 8 through the ink supply port, and is ejected (ejected) from the nozzle 80. Ink not ejected from the nozzle 80 passes through the ink discharge port and returns to the ink chamber. The ink circulates between the ink chamber and the inkjet head 8. While moving in the scanning direction together with the carrier 6, the four inkjet heads 8 eject four color inks supplied from the auxiliary tank 7 onto the recording paper 200.

[0039] As in Figure 1 As depicted, compared to the table 2, the conveyor roller 4 is arranged on the upstream side (rear side) in the conveying direction. Compared to the table 2, the conveyor roller 5 is arranged on the downstream side (front side) in the conveying direction. The two conveyor rollers 4 and 5 are driven synchronously by a motor (not depicted). The two conveyor rollers 4 and 5 convey the recording paper 200 placed on the table 2 in a conveying direction orthogonal to the scanning direction. The printing device 1 is provided with a controller 50. The controller 50 is provided with, for example, a CPU or logic circuit (e.g., FPGA), and a memory (storage device) 55 such as non-volatile memory and RAM. The controller 50 receives print jobs and drive waveform data from an external device 100, and the controller 50 stores the print jobs and drive waveform data in the memory 55. The controller 50 controls, for example, the drive of the ink dispensing device 3 and the conveyor roller 4 to perform printing processing based on the print jobs.

[0040] Figure 2 This is a schematic, partially enlarged cross-sectional view of the inkjet head 8. The inkjet head 8 is provided with a plurality of pressure chambers 81. The plurality of pressure chambers 81 constitute a plurality of pressure chamber arrays. A vibrating plate 82 is formed on the upper side of the pressure chamber 81. A layered piezoelectric element 83 is formed on the upper side of the vibrating plate 82. A first common electrode 84 is formed on the upper side of each of the pressure chambers 81 between the piezoelectric element 83 and the vibrating plate 82.

[0041] The second common electrode 86 is disposed inside the piezoelectric component 83. The second common electrode 86 is arranged on the upper side of each of the pressure chambers 81 and on the upper side of the first common electrode 84. The second common electrode 86 is positioned not opposite the first common electrode 84. Individual electrodes 85 are formed on the upper surface of the piezoelectric component 83 on the upper side of each of the pressure chambers 81. The individual electrodes 85 are vertically opposite the first common electrode 84 and the second common electrode 86, with the piezoelectric component 83 interposed therebetween. The vibrating plate 82, the piezoelectric component 83, the first common electrode 84, the individual electrodes 85, and the second common electrode 86 constitute the actuator 88.

[0042] A nozzle plate 87 is disposed below or beneath each pressure chamber 81. A plurality of vertically penetrating nozzles 80 are formed through the nozzle plate 87. Each of the nozzles 80 is arranged on the underside of each of the pressure chambers 81. The plurality of nozzles 80 constitute a plurality of nozzle arrays extending along the array of pressure chambers.

[0043] The first common electrode 84 is connected to the COM terminal, i.e., ground in this embodiment. The second common electrode 86 is connected to the VCOM terminal. The VCOM voltage is higher than the COM voltage. Individual electrode 85 is connected to switch group 54 (see...). Figure 3 A high or low voltage is applied to the individual electrode 85. The piezoelectric component 83 deforms, and the vibrating plate 82 vibrates. Based on the vibration of the vibrating plate 82, ink is discharged from the pressure chamber 81 through the nozzle 80.

[0044] Figure 3 This is a block diagram of controller 50. Controller 50 includes control circuitry 51, a D / A converter (digital-to-analog converter) 52, an amplifier 53, a switch group 54, and a memory 55.

[0045] The drive waveform data is stored in memory 55. The drive waveform data is data representing the voltage waveform applied to the individual electrode 85 (i.e., the drive waveform used to drive the actuator 88).

[0046] The driving waveform data is quantized data. In this embodiment, the driving waveform data Da, Db, and Dc are stored in memory 55.

[0047] The D / A converter 52 converts the digital signal into an analog signal. The amplifier 53 amplifies the analog signal. The switch group 54 is provided with a plurality of nth switches 54(n) (n = 1, 2, ..., N). Each of the plurality of nth switches 54(n) is configured, for example, by an analog switch IC. One end of each of the plurality of nth switches 54(n) is connected to the amplifier 53 via a common bus. The other end of each of the plurality of nth switches 54(n) is connected to an individual electrode 85 corresponding to each of the plurality of nozzles 80. In other words, one nth switch 54(n) is provided for one actuator 88.

[0048] The first capacitor 89a is configured with an individual electrode 85, a first common electrode 84, and a piezoelectric component 83. The second capacitor 89b is configured with an individual electrode 85, a second common electrode 86, and a piezoelectric component 83.

[0049] Figure 4This is an explanatory drawing used to illustrate examples of drive waveforms A, B, and C. Each of drive waveforms A, B, and C is a waveform provided to cause the piezoelectric component 83 to deform, the vibrating plate 82 to vibrate, and to allow ink present in the pressure chamber 81 to be discharged via the nozzle 80 after passing through the descender according to the vibration of the vibrating plate 82. For example, drive waveform A is a waveform provided for discharging large droplets. Drive waveform B is a waveform provided for discharging medium droplets. Drive waveform C is a waveform provided for discharging large droplets, but drive waveform C has a different discharge timing than drive waveform A. Figure 4 In the middle, compared with the left side, the right side indicates the past state. Figures 5 to 7 , Figure 10 and Figure 15 The states depicted are described in the same manner as described above. Driving waveform data Da is the quantized data of driving waveform A, driving waveform data Db is the quantized data of driving waveform B, and driving waveform data Dc is the quantized data of driving waveform C. Driving waveform data Da has quantized data Ak (k = 0, 1, 2, ..., K), driving waveform data Db has quantized data Bk (k = 0, 1, 2, ..., K), and driving waveform data Dc has quantized data Ck (k = 0, 1, 2, ..., K).

[0050] Figure 5 These are explanatory plots used to interpret examples of time-series data, analog signals, and time-division multiplexed signals. Figure 5In the diagram, A, B, and C respectively indicate the correspondence with the drive waveforms A, B, and C. When the actuator 88 is driven, the control circuit 51 accesses the memory 55 to obtain the drive waveform data Da, Db, and Dc to prepare the time series data. In the time series data, data Ak, Bk, and Ck are arranged sequentially when a time interval Δt is provided. The data Ak, Bk, and Ck are arranged in the order A0, B0, C0, A1, B1, C1, ..., AK, BK, CK. The time series data is a digital signal. Note that the time interval Δt is the reciprocal of the predetermined sampling frequency. The quantized data Ak, Bk, and Ck are arranged in the order A0, B0, C0, A1, B1, C1, ..., AK, BK, CK for each time interval corresponding to the reciprocal of the predetermined sampling frequency. In other words, the data length of the quantized data Ak, Bk, and Ck is no greater than the length corresponding to the reciprocal of the predetermined sampling frequency. Furthermore, quantized data A0 is continuous with quantized data B0, quantized data B0 is continuous with quantized data C0, and quantized data C0 is continuous with quantized data A1. In other words, between quantized data A0 and quantized data B0, quantized data C0, any other quantized data, and any data of any other waveform are not present. Furthermore, between quantized data B0 and quantized data C0, quantized data A0, any other quantized data, and any data of any other waveform are not present. Furthermore, between quantized data C0 and quantized data A1, quantized data B0, any other quantized data, and any data of any other waveform are not present. Note that the sampling frequency is 24MHz. The data length of each of the quantized data Ak, Bk, and Ck is approximately 41ns.

[0051] Control circuit 51 outputs time-series data to D / A converter 52. For example, in... Figure 5 As depicted, the D / A converter 52 converts time-series data into an analog signal that is output to the amplifier 53. The amplifier 53 amplifies the input analog signal, and the amplified signal is output to the switch group 54. (As shown in...) Figure 5 As depicted, the analog signal amplified by amplifier 53 is configured as a time-division multiplexed signal. In other words, the time-division multiplexed signal is not merely an analog signal corresponding only to data Ak, only to data Bk, and only to data Ck. Furthermore, the time-division multiplexed signal is a signal that makes the analog signals corresponding to at least a total of three data sets (i.e., a set of one data Ak, one data Bk, and one data Ck) and the analog signals corresponding to a total of three data sets (i.e., a set of one data Ak+1, one data Bk+1, and one data Ck+1) continuous in the time series. For example, in... Figure 5 The number of signals in a time-division multiplexed signal is one. (Reference) Figure 5The analog signal corresponding to data C0 appears to be isolated. However, this is due to the fact that the analog signal corresponding to the set of three data points (i.e., the set of data A0, data B0, and data C0) and in the state where data A0 and data B0 are zero is continuous in the time series with the analog signal corresponding to the set of three data points (i.e., the set of data A1, data B1, and data C1) and in the state where data A1 is zero. Furthermore, the analog signal corresponding to the set of data AK and data BK appears to be isolated. However, this is due to the fact that the analog signal corresponding to the set of three data points (i.e., the set of data AK-1, data BK-1, and data CK-1) and in the state where data CK-1 is zero is continuous in the time series with the analog signal corresponding to the set of three data points (i.e., the set of data AK, data BK, and data CK). Furthermore, the reason why the analog signal corresponding to the set of data AK-1 and data BK-1 appears isolated is the same or equivalent to the above. Therefore, in Figure 5 The analog signal depicted can be treated as a time-division multiplexed signal. In the time-division multiplexed signal, it is assumed that the portion corresponding to data Ak-1 is designated as "part one," the portion corresponding to data Ak is designated as "part two," the portion corresponding to data Bk-1 is designated as "part three," and the portion corresponding to data Bk is designated as "part four." Based on this assumption, part three exists (arranged) between part one and part two, and part two exists (arranged) between part three and part four. In other words, part one is continuous with part three, part three is continuous with part two, and part two is continuous with part four. That is, in the time-division multiplexed signal, part two, part four, and any other waveforms do not exist between part one and part three. Furthermore, in the time-division multiplexed signal, part one, part four, and any other waveforms do not exist between part three and part two. Furthermore, in the time-division multiplexed signal, part one, part three, and any other waveforms do not exist between part two and part four. Note that the same or equivalent relationship also holds between data Ak and data Ck, and the same or equivalent relationship also holds between data Bk and data Ck. Control circuitry 51, D / A converter 52, amplifier 53, and memory 55 configure a multiplexer (multiplexing unit, signal generator). A time-division multiplexed signal is included in one emission drive cycle. For example, if the emission drive frequency (injection frequency) is 100 kHz, then one emission drive cycle (injection cycle) is 10 μs, and a time-division multiplexed signal has a length of less than 10 μs. Preferably, three or more data Ak, three or more data Bk, and three or more data Ck exist in one time-division multiplexed signal. The reason will be described later.

[0052] The control circuit 51 outputs a switch control signal S1 for controlling the opening / closing of multiple nth switches 54(n), a synchronization signal S2a corresponding to drive waveform A, a synchronization signal S2b corresponding to drive waveform B, and a synchronization signal S2c corresponding to drive waveform C to the switch group 54. Note that the three synchronization signals S2a, S2b, and S2c are also simply referred to as "synchronization signal S2" (see...). Figure 3 The switch control signal S1 includes first selection information indicating that any one of the plurality of nth switches 54(n) is selected, and second selection information indicating that any one of the three synchronization signals S2a, S2b, S2c is selected. The first selection information and the second selection information are associated.

[0053] Figure 6 This is an explanatory diagram used to explain the relationship between the time-division multiplexed signals 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 rise time of the pulse of synchronization signal S2a and the rise time of the pulse of synchronization signal S2b. Furthermore, a time interval Δt is provided between the rise time of the pulse of synchronization signal S2b and the rise time of the pulse of synchronization signal S2c, and a time interval Δt is provided between the rise time of the pulse of synchronization signal S2c and the rise time of the pulse of synchronization signal S2a. As described above, the data Ak, Bk, and Ck that configure the time-series data are arranged sequentially while providing the time interval Δt. Therefore, if the time-division multiplexed signal is accessed at the rise time of the pulse of synchronization signal S2a, the drive waveform signal Pa corresponding to the data Ak and representing the drive waveform A can be obtained. If the time-division multiplexed signal is accessed at the rising time of the pulse of the synchronization signal S2b, the drive waveform signal Pb corresponding to data Bk and representing drive waveform B can be obtained. If the time-division multiplexed signal is accessed at the rising time of the pulse of the synchronization signal S2c, the drive waveform signal Pc corresponding to data Ck and representing drive waveform C can be obtained. In other words, a type of time-division multiplexed signal is input into an nth switch 54(n), and the nth switch 54(n) separates any one of the drive waveform signal Pa representing drive waveform A, the drive waveform signal Pb representing drive waveform B, and the drive waveform signal Pc representing drive waveform C.

[0054] Switch group 54 turns the selected nth switch 54(n) on / off at the time indicated by the selected synchronization signals S2a to S2c. In other words, switch group 54 turns the nth switch 54(n) on / off according to a predetermined sampling frequency.

[0055] Figure 7This is a schematic drawing of the drive waveform input to actuator 88 by opening / closing the nth switch 54(n). When the synchronization signal S2a is selected, the switch group 54 closes the nth switch 54(n) if the pulse of the synchronization signal S2a is in a high-level interval (period), or the switch group 54 opens the nth switch 54(n) if the pulse of the synchronization signal S2a is in a low-level interval (period). When the nth switch 54(n) is closed, the charge applied to the individual electrode 85 is held by the first capacitor 89a and the second capacitor 89b. Figure 7 As depicted, the drive waveform A1 is input to the actuator 88. In other words, the drive waveform signal Pa is separated from the time-division multiplexed signal according to a predetermined sampling frequency, and the actuator 88 is driven by the drive waveform signal Pa. Note that three or more data Ak are required to express the concave / convex (non-uniform) shape of the drive waveform signal Pa.

[0056] When the synchronization signal S2b is selected, if the pulse of the synchronization signal S2b is in a high-level interval, then the switch group 54 closes the nth switch 54(n), or if the pulse of the synchronization signal S2b is in a low-level interval, then the switch group 54 opens the nth switch 54(n). When the nth switch 54(n) is closed, the charge applied to the individual electrode 85 is held by the first capacitor 89a and the second capacitor 89b. Figure 7 As depicted, the drive waveform B1 is input into the actuator 88. In other words, the drive waveform signal Pb is separated from the time-division multiplexed signal according to a predetermined sampling frequency, and the actuator 88 is driven by the drive waveform signal Pb. Note that three or more data points Bk are required to express the concave / convex (non-uniform) shape of the drive waveform signal Pb.

[0057] When the synchronization signal S2c is selected, if the pulse of the synchronization signal S2c is in a high-level interval, then the switch group 54 closes the nth switch 54(n), or if the pulse of the synchronization signal S2c is in a low-level interval, then the switch group 54 opens the nth switch 54(n). When the nth switch 54(n) is closed, the charge applied to the individual electrode 85 is held by the first capacitor 89a and the second capacitor 89b. Figure 7 As depicted, the drive waveform C1 is input into the actuator 88. In other words, the drive waveform signal Pc is separated from the time-division multiplexed signal according to a predetermined sampling frequency, and the actuator 88 is driven by the drive waveform signal Pc. Note that three or more data Ck are required to express the concave / convex (non-uniform) shape of the drive waveform signal Pc.

[0058] The predetermined sampling frequency described above is not less than the resonant frequency of the inkjet head 8. The resonant frequency of the inkjet head 8 is either the resonant frequency provided when the pressure chamber 81 is not filled with ink (liquid), or the resonant frequency provided when the pressure chamber 81 is filled with ink. For example, if the resonant frequency of the inkjet head 8 provided when the pressure chamber 81 is not filled with ink is 100 kHz, then the resonant frequency of the inkjet head 8 provided when the pressure chamber 81 is filled with ink is less than 100 kHz. Specifically, the resonant frequency of the inkjet head 8 provided when the pressure chamber 81 is filled with ink is 90 kHz. In other words, the resonant frequency of the inkjet head 8 provided when the pressure chamber 81 is not filled with ink is greater than the resonant frequency of the inkjet head 8 provided when the pressure chamber 81 is filled with ink.

[0059] Figure 8 This is a flowchart explaining the printing process performed by controller 50. Controller 50 determines whether a print job has been received from external device 100 (S1). If no print job is received (S1: No), controller 50 returns the process to step S1. If a print job is received (S1: Yes), controller 50 performs a flashing process (S2). The flashing process is the process in which ink is discharged from nozzle 80 for any purpose other than printing. The flashing process is performed, for example, at or above the flash receiver 21.

[0060] The controller 50 executes a print job (S3). A print job is a unit used to construct a print position. Specifically, a print job is a liquid discharge process performed during the period in which the inkjet head 8 moves to the right or left by an amount corresponding to the left and right width of the recording paper 200. Subsequently, the controller 50 determines whether a print job is completed (S4). Note that the carrier 6 performs one scan in a print job. If a print job is not completed (S4: No), the process returns to step S4. If a print job is completed (S4: Yes), the controller 50 determines whether the print job is completed (S5).

[0061] If a print job is completed (S5: Yes), the controller 50 performs the flashing process (S8), and the printing process terminates. If a print job is not completed (S5: No), the controller 50 determines whether the timing for performing the flashing process has arrived (S6). In a print job, the time-division multiplexed signal is configured only by analog signals, and the type of analog signals remains unchanged. The analog signals include three types of analog signals. In a discharge drive cycle, ranging from the rise to the fall of the time-division multiplexed signal, the time-division multiplexed signal is also configured by three types of analog signals, and the type of analog signals is not changed. For nozzle 80 maintenance, the flashing process is performed periodically. If the timing for performing the flashing process arrives (S6: Yes), the controller 50 performs the flashing process (S7), and the process returns to step S3. If the timing for performing the flashing process has not arrived (S6: No), the controller 50 determines whether the timing for performing non-discharge flashing processing has arrived (S9).

[0062] The non-discharge flashing process is performed to prevent the nozzle 80 from drying out without ink discharge. Specifically, the piezoelectric component 83 slightly deforms during this process to oscillate the surface (meniscus) of the ink. For example, this process is performed at or above the cap 20. The non-discharge flashing is performed periodically. If the timing for performing the non-discharge flashing process arrives (S9: Yes), the controller 50 performs the non-discharge flashing process (S10), and the process returns to step S3. In step S10, the controller 50 supplies a drive waveform corresponding to the non-discharge flashing process to the individual electrode 85. If the timing for performing the non-discharge flashing process does not arrive (S9: No), the controller 50 returns the process to step S3.

[0063] The controller 50 can perform the generation of the time-division multiplexed signal and the separation of the drive waveform signal during either the execution of the flashing process (S2, S7, S8) or the execution of the print task (S3). That is, the generation of the time-division multiplexed signal and the separation of the drive waveform signal can be performed during the driving of the actuator 88.

[0064] In the inkjet head 8 and printing apparatus 1 according to the first embodiment, the time-division multiplexed signal is generated based on the respective drive waveform data Da, Db, Dc representing each drive waveform A, B, C. The drive waveform signal Pa representing drive waveform A, the drive waveform signal Pb representing drive waveform B, and the drive waveform signal Pc representing drive waveform C are separated from the generated time-division multiplexed signal. The actuator 88 is driven by the drive waveform signals Pa, Pb, or Pc. The amplitude of the drive waveform applied to the actuator 88 can be adjusted by selecting the drive waveform signals Pa, Pb, or Pc. Furthermore, only the period of any one of the selected drive waveforms A, B, or C is included in one period for printing one pixel, and the period of the unselected drive waveform is not included. Therefore, the nozzle 80 waiting time can be reduced.

[0065] The control circuit 51 reads the data values ​​of drive waveform data Da, Db, and Dc from the memory 55, and the data values ​​are sent in a time sequence. Therefore, the generation of time-division multiplexed signals can be realized.

[0066] The control circuit 51 inputs the data values ​​of the drive waveform data Da, Db, and Dc into the D / A converter 52, and the data values ​​are amplified by the amplifier 53. Therefore, the amplitude of the time-division multiplexed signal can be increased.

[0067] The drive waveform signal Pa, representing drive waveform A, the drive waveform signal Pb, representing drive waveform B, and the drive waveform signal Pc, representing drive waveform C, are separated from the time-division multiplexed signal at a sampling frequency not less than the resonant frequency of the inkjet head 8. The resonant frequency of the inkjet head 8 is the resonant frequency provided when the pressure chamber 81 is not filled with ink. Therefore, sampling errors do not affect the operation of the actuator 88. Sampling errors can be ignored.

[0068] The drive waveform signal Pa, representing drive waveform A, the drive waveform signal Pb, representing drive waveform B, and the driven waveform signal Pc, representing drive waveform C, are separated from the time-division multiplexed signal at a sampling frequency not less than the resonant frequency of the inkjet head 8. The resonant frequency of the inkjet head 8 is the resonant frequency provided when the pressure chamber 81 is filled with ink. In this case, when the circuit is prepared, the increase in the number of switching amplifiers can be suppressed.

[0069] The time-division multiplexed signal is input to switch group 54. Furthermore, switch control signal S1 and synchronization signals S2a to S2c, indicating the on / off timing, are input to the nth switch 54(n). The nth switch 54(n) is turned on / off based on the switch control signal S1 and the synchronization signals S2a to S2c. Drive waveform signals Pa to Pc can be separated from the time-division multiplexed signal.

[0070] The control circuit 51 outputs the switch control signal S1 and the synchronization signals S2a to S2c to the switch group 54 to control the opening / closing of the nth switch 54(n).

[0071] In the first embodiment, the actuator 88 has a three-layer structure. However, the actuator 88 may have a two-layer structure. The actuator 88 is based on a piezoelectric system. However, the actuator 88 may be based on a bubble jet system (ink-heated inkjet system) or an electrostatic system. The number of waveform signals is not limited to three. The number may be two, four, or more.

[0072] (Second Embodiment)

[0073] The present invention will be explained below based on drawings depicting the printing apparatus 1 according to the second embodiment. Components that are the same as or equivalent to those in the first embodiment, and whose components are also labeled with the same reference numerals as those in the first embodiment, will be omitted from any detailed explanation. Figure 9 This is a block diagram of controller 50. Figure 10 It is an interpretive plot used to explain the relationship between analog signals 60A to 60C and time-division signals S3a to S3c.

[0074] The controller 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.

[0075] When actuator 88 is driven, control circuit 51 accesses memory 55 to obtain drive waveform data Da, which is output to the first D / A converter 52a. Control circuit 51 accesses memory 55 to obtain drive waveform data Db, which is output to the second D / A converter 52b. Control circuit 51 accesses memory 55 to obtain drive waveform data Dc, which is output to the third D / A converter 52c.

[0076] As in Figure 10 As depicted, 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 the time-division signal S3a corresponding to analog signal 60A, the time-division signal S3b corresponding to analog signal 60B, and the time-division signal S3c corresponding to analog signal 60C to the second switch control unit 56. Note that the three time-division signals S3a, S3b, and S3c are also simply referred to as "time-division signal S3" (see...). Figure 9 ).

[0077] Time-division signals S3a, S3b, and S3c are pulse waves. A time interval Δt is provided between the rise time of the pulse of time-division signal S3a and the rise time of the pulse of time-division signal S3b. Furthermore, a time interval Δt is provided between the rise time of the pulse of time-division signal S3b and the rise time of the pulse of time-division signal S3c, and a time interval Δt is provided between the rise time of the pulse of time-division signal S3c and the rise time of the pulse of time-division signal S3a. Each time-division signal S3a, S3b, and S3c corresponds to each of the synchronization signals S2a, S2b, and S2c described above.

[0078] If the pulse of time-division signal S3a is in a high-level interval, the first switch 56a is closed; or if the pulse of time-division signal S3a is in a low-level interval, the first switch 56a is open. If the pulse of time-division signal S3b is in a high-level interval, the second switch 56b is closed; or if the pulse of time-division signal S3b is in a low-level interval, the second switch 56b is open. If the pulse of time-division signal S3c is in a high-level interval, the third switch 56c is closed; or if the pulse of time-division signal S3c is in a low-level interval, the third switch 56c is open. Note that, for the following reason, the first switch 56a, the second switch 56b, and the third switch 56c may be opened simultaneously in some cases, but they may not be closed simultaneously. That is, if the first switch 56a, the second switch 56b, and the third switch 56c are closed simultaneously, analog signals 60A, 60B, and 60C exist in a mixed manner. Note that analog signals 60A, 60B, and 60C do not exist in a mixed manner. Therefore, in the time-division multiplexed signal, a portion of analog signal 60A is continuous with a portion of analog signal 60B, a portion of analog signal 60B is continuous with a portion of analog signal 60C, and a portion of analog signal 60C is continuous with a portion of analog signal 60A. In other words, in the time-division multiplexed signal, between the portions of analog signal 60A and analog signal 60B, there is no analog signal 60C or any other analog signal of any other waveform. Furthermore, in the time-division multiplexed signal, between the portions of analog signal 60B and analog signal 60C, there is no analog signal 60A or any other analog signal of any other waveform. Furthermore, in the time-division multiplexed signal, between the portions of analog signal 60C and analog signal 60A, there is no analog signal 60B or any other analog signal of any other waveform.

[0079] The combined signal obtained by combining analog signals 60A to 60C is output from the second switch control unit 56. The combined signal is... Figure 5The combined signal is the same as or equivalent to the analog signal described in the diagram. The combined signal is amplified by amplifier 53, and amplifier 53 outputs a time-division multiplexed signal. The time-division multiplexed signal is the same as or equivalent to the analog signal described in the diagram. Figure 5 The time-division multiplexed signals depicted are the same or equivalent signals. The time-division multiplexed signals are input to switch group 54. The switching control of switch group 54 and the driving of actuator 88 are implemented in the same manner as in the first embodiment.

[0080] In the printing apparatus 1 according to the second embodiment, the data value of drive waveform data Da is read from memory 55 and input into a first D / A converter 52a to generate an analog signal 60A. Furthermore, the data value of drive waveform data Db is read from memory 55 and input into a second D / A converter 52b to generate an analog signal 60B. Furthermore, the data value of drive waveform data Dc is read from memory 55 and input into a third D / A converter 52c to generate an analog signal 60C. A first switch 56a is turned on / off based on a first time-division signal S3a indicating an on / off timing, a second switch 56b is turned on / off based on a second time-division signal S3b indicating an on / off timing different from that of the first time-division signal S3a, and a third switch 56c is turned on / off based on a third time-division signal S3c indicating an on / off timing different from that of the first and second time-division signals S3a and S3b. Therefore, a time-division multiplexed signal can be generated from each of the analog signals 60A to 60C.

[0081] The printing device 1 according to the second embodiment can be modified to have the following configuration. Figure 11This is a block diagram of controller 50 according to a variant embodiment. In the variant embodiment, three amplifiers 53a to 53c are provided instead of amplifier 53. Furthermore, the analog signal from the first D / A converter 52a is input into amplifier 53a, and amplifier 53a outputs the analog signal to a first switch 56a. The analog signal from the second D / A converter 52b is input into amplifier 53b, and amplifier 53b outputs the analog signal to a second switch 56b. The analog signal from the third D / A converter 52c is input into amplifier 53c, and amplifier 53c outputs the analog signal to a third switch 56c. The first to third switches 56a to 56c are turned on / off based on first to third time-division multiplexed signals S3a to S3c, and time-division multiplexed signals are generated. In other words, in the time-division multiplexed signal, a portion of the analog signal 60A output from amplifier 53a is continuous with a portion of the analog signal 60B output from amplifier 53b, a portion of the analog signal 60B output from amplifier 53b is continuous with a portion of the analog signal 60C output from amplifier 53c, and a portion of the analog signal 60C output from amplifier 53c is continuous with a portion of the analog signal 60A output from amplifier 53a. That is, in the time-division multiplexed signal, between the portion of analog signal 60A output from amplifier 53a and the portion of analog signal 60B output from amplifier 53b, there is no analog signal from amplifier 53c outputting analog signal 60C or any other waveform. Furthermore, in the time-division multiplexed signal, between the portion of analog signal 60B output from amplifier 53b and the portion of analog signal 60C output from amplifier 53c, there is no analog signal from amplifier 53a outputting analog signal 60A or any other waveform. Furthermore, in the time-division multiplexed signal, there is no analog signal of any other waveform between the portion of analog signal 60C output from amplifier 53c and the portion of analog signal 60A output from amplifier 53a, the portion of analog signal 60B output from amplifier 53b, and any other analog signal. By using three amplifiers, the bandwidth of each amplifier can be narrowed. Time-division multiplexing is easy to implement.

[0082] (Third Embodiment)

[0083] The present invention will be explained below based on drawings depicting printing apparatus 1 according to a third embodiment. Components that are identical or equivalent to those in the first or second embodiments to those in the first and / or second embodiments are labeled with the same reference numerals, and no detailed explanation thereof will be omitted. Figure 12 This is a block diagram of controller 50.

[0084] The controller 50 includes, for example, 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 unit 57, and a sample-and-hold unit 58 (S / H unit). The third switch control unit 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).

[0085] Control circuit 51 outputs time-series data to D / A converter 52. D / A converter 52 converts the time-series data into an analog signal that is output to sample-and-hold unit 58. The analog signal output by D / A converter 52 is compared with the data in... Figure 5 The analog signals depicted are the same or equivalent.

[0086] Control circuit 51 outputs sampling signals S4a to S4c, indicating the sampling period, to sample-and-hold unit 58. Sampling signal S4a is input to the first sample-and-hold circuit 58a, sampling signal S4b is input to the second sample-and-hold circuit 58b, and sampling signal S4c is input to the third sample-and-hold circuit 58c. The sampling periods of each sampling signal S4a to S4c are different, and they deviate from each other by a time interval Δt. Note that the three sampling signals S4a, S4b, and S4c are also simply referred to as "sampling signal S4" (see...). Figure 12 ).

[0087] The first sample-and-hold circuit 58a samples and holds the analog signal according to the sampling period of the sampling signal S4a, and the signal is output to amplifier 53d. The second sample-and-hold circuit 58b samples and holds the analog signal according to the sampling period of the sampling signal S4b, and the signal is output to amplifier 53e. The third sample-and-hold circuit 58c samples and holds the analog signal according to the sampling period of the sampling signal S4c, and the signal is output to amplifier 53f.

[0088] The analog signal output by the first sample-and-hold circuit 58a and the Figure 10 The analog signal 60A depicted is the same as or equivalent to that described in the diagram. The analog signal output by the second sample-and-hold circuit 58b is the same as that in the diagram. Figure 10 The analog signal 60B described is the same as or equivalent to the analog signal 60B. The analog signal output by the third sample-and-hold circuit 58c is the same as the analog signal in... Figure 10 The analog signal 60C described in the text is the same as or equivalent to it.

[0089] Amplifier 53d amplifies the analog signal and outputs the signal to the first switch 57a. Amplifier 53e amplifies the analog signal and outputs the signal to the second switch 57b. Amplifier 53f amplifies the analog signal and outputs the signal to the third switch 57c.

[0090] Control circuit 51 outputs the time-division signal S5a corresponding to the analog signal output by amplifier 53d, the time-division signal S5b corresponding to the analog signal output by amplifier 53e, and the time-division signal S5c corresponding to the analog signal output by amplifier 53f to the third switch control unit 57. Note that the three time-division signals S5a, S5b, and S5c are also simply referred to as "time-division signal S5" (see...). Figure 12 ).

[0091] Time-division signals S5a, S5b, and S5c are related to... Figure 10 The time-division signals S3a, S3b, and S3c depicted are identical or equivalent pulse waves. A time interval Δt is provided between the rise time of the pulse of time-division signal S5a and the rise time of the pulse of time-division signal S5b. Furthermore, a time interval Δt is provided between the rise time of the pulse of time-division signal S5b and the rise time of the pulse of time-division signal S5c, and a time interval Δt is provided between the rise time of the pulse of time-division signal S5c and the rise time of the pulse of time-division signal S5a. Each time-division signal S5a, S5b, and S5c corresponds to each of the synchronization signals S2a, S2b, and S2c described above.

[0092] If the pulse of time-division signal S5a is in a high-level interval, the first switch 57a is closed; or if the pulse of time-division signal S5a is in a low-level interval, the first switch 57a is open. If the pulse of time-division signal S5b is in a high-level interval, the second switch 57b is closed; or if the pulse of time-division signal S5b is in a low-level interval, the second switch 57b is open. If the pulse of time-division signal S5c is in a high-level interval, the third switch 57c is closed; or if the pulse of time-division signal S5c is in a low-level interval, the third switch 57c is open. Note that, for the following reason, the first switch 57a, the second switch 57b, and the third switch 57c may be opened simultaneously in some cases, but they may not be closed simultaneously. That is, if the first switch 57a, the second switch 57b, and the third switch 57c are closed simultaneously, analog signals 60A, 60B, and 60C exist in a mixed manner. Note that analog signals 60A, 60B, and 60C do not exist in a mixed manner. Therefore, in the time-division multiplexed signal, a portion of the analog signal 60A output from amplifier 53d is continuous with a portion of the analog signal 60B output from amplifier 53e, a portion of the analog signal 60B output from amplifier 53e is continuous with a portion of the analog signal 60C output from amplifier 53f, and a portion of the analog signal 60C output from amplifier 53f is continuous with a portion of the analog signal 60A output from amplifier 53d. In other words, in the time-division multiplexed signal, between the portion of analog signal 60A output from amplifier 53d and the portion of analog signal 60B output from amplifier 53e, there is no analog signal from amplifier 53f outputting analog signal 60C or any other waveform. Furthermore, in the time-division multiplexed signal, between the portion of analog signal 60B output from amplifier 53e and the portion of analog signal 60C output from amplifier 53f, there is no analog signal from amplifier 53d outputting analog signal 60A or any other waveform. Furthermore, in the time-division multiplexed signal, there is no analog signal of any other waveform between the portion of analog signal 60C output from amplifier 53f and the portion of analog signal 60A output from amplifier 53d.

[0093] The combined signal (i.e., time-division multiplexed signal) obtained by combining the analog signals output from amplifiers 53d to 53f is output from the third switch control unit 57. The time-division multiplexed signal is... Figure 5 The time-division multiplexed signals depicted are the same or equivalent signals. The time-division multiplexed signals are input to switch group 54. The switching control of switch group 54 and the driving of actuator 88 are implemented in the same manner as in the first embodiment.

[0094] Note that the sampling time point indicated by the sampling signal S4a is earlier than the closing time point indicated by the time-division signal S5a, the sampling time point indicated by the sampling signal S4b is earlier than the closing time point indicated by the time-division signal S5b, and the sampling time point indicated by the sampling signal S4c is earlier than the closing time point indicated by the time-division signal S5c.

[0095] In the printing apparatus 1 according to the third embodiment, the data values ​​of each drive waveform data Da, Db, and Dc are read from the memory 55 and input into the D / A converter 52 in a time sequence. The first sample-and-hold circuit 58a operates based on the first sample signal S4a, the second sample-and-hold circuit 58b operates based on the second sample signal S4b, and the third sample-and-hold circuit 58c operates based on the third sample signal S4c. The first to third switches 57a to 57c can be turned on / off based on the time-division signals S5a to S5c to generate time-division multiplexed signals.

[0096] Furthermore, the sampling time indicated by sampling signal S4a is earlier than the shutdown time indicated by time-division signal S5a, the sampling time indicated by sampling signal S4b is earlier than the shutdown time indicated by time-division signal S5b, and the sampling time indicated by sampling signal S4c is earlier than the shutdown time indicated by time-division signal S5c. Therefore, the influence exerted on the generation of the time-division multiplexed signal can be suppressed, which would otherwise be caused by the delay between time-division signals S5a and S5c.

[0097] (Fourth Embodiment)

[0098] The present invention will now be explained based on drawings depicting a printing apparatus 1 according to a fourth embodiment. Components that are identical or equivalent to those in the first to third embodiments are labeled with the same reference numerals as those in the first to third embodiments, and no detailed explanation thereof will be omitted. Figure 13 This is a block diagram of controller 50.

[0099] The controller 50 includes a control circuit 51, a digital amplifier 530 into which digital data can be directly input, a low-pass filter 59 (LPF), a switch group 54, and a memory 55. The digital amplifier 530 includes switching and amplification circuits. The control circuit 51 outputs time-series data (digital data) to the digital amplifier 530. The digital amplifier 530 amplifies the time-series data, and the amplified data is output to the low-pass filter 59. In other words, in the time-division multiplexed signal, quantized data A0 is continuous with quantized data B0, quantized data B0 is continuous with quantized data C0, and quantized data C0 is continuous with quantized data A1. That is, in the time-division multiplexed signal, between quantized data A0 and quantized data B0, quantized data C0, any other quantized data, and any data of any other waveform are absent. Furthermore, in the time-division multiplexed signal, between quantized data B0 and quantized data C0, quantized data A0, any other quantized data, and any data of any other waveform are absent. Furthermore, in the time-division multiplexed signal, between quantized data C0 and quantized data A0, there is no quantized data B0, any other quantized data, or any other waveform data. The low-pass filter 59 converts the pulse wave output by the digital amplifier 530 into an analog signal, and the time-division multiplexed signal configured by the analog signal is output to the switch group 54. The switching control of the switch group 54 and the driving of the actuator 88 are the same as or equivalent to those in the first embodiment. Note that the output of the digital amplifier 530 has a pulse shape that is not a continuous waveform. Therefore, the output of the digital amplifier 530 is not an analog signal. That is, the output of the digital amplifier 530 is a time-division multiplexed signal configured by a digital signal.

[0100] In the printing apparatus according to the fourth embodiment, the data values ​​of each drive waveform data Da, Db, and Dc are read from the memory 55 and input into the digital amplifier 530. Therefore, a time-division multiplexed signal can be generated. The use of the digital amplifier 530 allows for a reduction in the size of the D / A converter. Compared to any analog amplifier, the digital amplifier 530 does not require highly accurate and highly stable components. Therefore, the digital amplifier 530 is resistant to environmental changes (such as temperature changes). Furthermore, the digital amplifier 530 has a long service life due to the small number of operating and component numbers.

[0101] (Fifth Embodiment)

[0102] The present invention will now be explained based on drawings depicting the printing apparatus 1 according to the fifth embodiment. Components that are identical or equivalent to those in the first to fourth embodiments are labeled with the same reference numerals as those in the first to fourth embodiments, and any detailed explanation thereof will be omitted. Figure 14 This is a block diagram of controller 50.

[0103] The controller 50 includes, for example, a control circuit 51, a D / A converter 52, an amplifier 53, an amplitude information generation circuit 70, a voltage determination (determination) circuit 71, and a variable voltage power supply 72. The control circuit 51 accesses the memory 55 to obtain the drive waveform data Da to Dc that are output to the D / A converter 52. The D / A converter 52 converts the drive waveform data Da to Dc into an analog signal that is output to the amplifier 53. The signal control implemented for those ranging from the amplifier 53 to the actuator 88 is implemented in the same manner as in the first to fourth embodiments, and any further explanation thereof will be omitted.

[0104] Control circuit 51 outputs a digital signal to amplitude information generation circuit 70 to generate information indicating the amplitude of the digital signal, and this information is output to voltage determination circuit 71. Voltage determination circuit 71 determines the voltage to be set for amplifier 53 based on the amplitude indication information. This determination is output to variable voltage power supply 72. Variable voltage power supply 72 supplies the determined voltage to amplifier 53. Note that the determined voltage is lower than the maximum voltage that can be supplied by variable voltage power supply 72.

[0105] Figure 15 This is an explanatory plot used to explain the relationship between the analog signal output from the D / A converter 52 and the voltage supplied to the amplifier 53. Figure 15 In the diagram, alternating long and short dashed lines indicate the voltage supplied to amplifier 53. (As shown in...) Figure 15 As depicted, a voltage that depends on the amplitude of the analog signal is supplied to amplifier 53. Compared to the case where the maximum voltage that can be supplied by the variable voltage power supply 72 is supplied to amplifier 53, power consumption can be reduced.

[0106] The printing apparatus 1 described above is based on a serial head system. However, the technology described above can be applied to any printing apparatus based on a line head system. Furthermore, the printing apparatus 1 described above is equipped with an inkjet head based on a piezoelectric system. However, the technology described above can be applied to any printing apparatus equipped with an inkjet head based on a bubble jet system (ink-heated inkjet system) or an inkjet head based on an electrostatic system. Specifically, when the technology described above is applied to a printing apparatus equipped with a head based on a bubble jet system (ink-heated inkjet system), the amplitudes of the drive waveforms A, B, and C are approximately the same, but the pulse widths are different; however, in the first embodiment, both the amplitude and the pulse width are different. Note that the electrostatic system-based inkjet head is configured, for example, by stacking a first substrate, a second substrate, and a third substrate, each of which is made of a silicon single-crystal substrate. The first substrate has a recess for constructing a liquid chamber in which the bottom wall is a vibrating plate. The second substrate is connected to the first substrate and has electrodes with a shape approximately the same as the vibrating plate. The third substrate is connected to the first substrate and has a portion of the liquid chamber, a nozzle, and a flow channel for connecting the liquid chamber and the nozzle. When a positive pulse voltage is applied from the oscillation circuit to the electrodes, the electrode surfaces become charged with a positive potential, and the corresponding vibrating plate becomes charged with a negative potential. The vibrating plate then warps, and the liquid chamber expands. Subsequently, when the pulse voltage application to the electrodes is turned off, the warped vibrating plate recovers, the liquid chamber contracts, the pressure in the liquid chamber increases, and ink is discharged from the nozzle. The materials of the first, second, and third substrates are not limited to silicon. The first, second, and third substrates can be made of glass, nickel, plastic, or stainless steel.

[0107] In the first embodiment, the resonant frequency of the inkjet head 8 is either the resonant frequency provided when the pressure chamber 81 is not filled with ink or the resonant frequency provided when the pressure chamber 81 is filled with ink. However, there are no limitations on this. The resonant frequency of the inkjet head 8 can be greater than the resonant frequency provided when the pressure chamber 81 is filled with ink and less than the resonant frequency provided when the pressure chamber 81 is not filled with ink.

[0108] In the first embodiment, time-series data is provided such that data Ak, Bk, and Ck are arranged sequentially when a time interval Δt is provided, i.e., the data are arranged in the order of A0, B0, C0, A1, B1, C1, ..., AK, BK, CK. However, various modifications can be made to the data Ak, Bk, and Ck. For example, when the time interval Δt is a shorter time interval Δt', the control circuit 51 generates data A'k, B'k, and C'k by refining some portions of the high-level interval and low-level interval, excluding the rising and falling portions of data Ak, Bk, and Ck. In other words, the time length of data A'k is shorter than the time length of data Ak. Furthermore, the time length of data B'k is shorter than the time length of data Bk. Furthermore, the time length of data C'k is shorter than the time length of data Ck. As time-series data, the control circuit 51 can use the data A'0, B'0, C'0, A'1, B'1, C'1, ..., A'K, B'K, C'K arranged in this order.

[0109] Furthermore, when the time interval Δt is a longer time interval Δt", the control circuit 51 generates data A"k, B"k, and C"k by extending the high-level interval and low-level interval, excluding the rising and falling portions of data Ak, Bk, and Ck. In other words, the duration of data A"k is longer than that of data Ak. Furthermore, the duration of data B"k is longer than that of data Bk. Furthermore, the duration of data C"k is longer than that of data Ck. As time-series data, the control circuit 51 can use data in which data A"0, B"0, C"0, A"1, B"1, C"1, ..., A"K, B"K, C"K are arranged in this order.

[0110] In the first embodiment, the control circuit 51 accesses the memory 55 to obtain drive waveform data Da, Db, and Dc, and prepares time-series data. In the time-series data, data Ak, Bk, and Ck are arranged sequentially when a time interval Δt is provided. However, there are no limitations on this. The control circuit 51 can prepare time-series data by accessing the memory 55, obtaining drive waveform data Da, Db, and Dc, and refining some portions 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. However, data arranged in the order of A0, B0, C0, A2, B2, C2, ..., AK, BK, and CK can be used as time-series data by using quantized data A0, A2, B0, B2, C0, and C2.

[0111] Furthermore, data arranged in the order A0, C0, B1, B3, C0, C2, where the data is in the sequence A0, C0, B1, A2, C2, B3, ..., AK-1, CK-1, BK can be used as time series data. Additionally, data arranged in the order B0, A1, C1, B2, A3, C3, ..., BK-1, AK, CK can also be used as time series data.

[0112] Furthermore, the control circuit 51 can access the memory 55 to acquire drive waveform data Da, Db, and Dc, and generate interpolation data based on the acquired drive waveform data Da, Db, and Dc. The control circuit 51 can also prepare time series data using the acquired drive waveform data Da, Db, and Dc and the interpolation data. Specifically, the drive waveform data Da has quantization data A0, A1, A2, and A3; the drive waveform data Db has quantization data B0, B1, B2, and B3; and the drive waveform data Dc has quantization data C0, C1, C2, and C3. Furthermore, control circuit 51 generates interpolated data A0.5 based on quantized data A0 and A1, interpolated data A1.5 based on quantized data A1 and A2, interpolated data B0.5 based on quantized data B0 and B1, interpolated data B1.5 based on quantized data B1 and B2, interpolated data C0.5 based on quantized data C0 and C1, and interpolated data C1.5 based on quantized data C1 and C2. Then, as time series data, control circuit 51 can 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, and quantized data A2, B2, C2, ..., AK, BK, CK.

[0113] Furthermore, control circuit 51 generates interpolation data A0.25 based on quantization data A0 and interpolation data A0.5, interpolation data A0.75 based on interpolation data A0.5 and quantization data A1, interpolation data B0.25 based on quantization data B0 and interpolation data B0.5, interpolation data B0.75 based on interpolation data B0.5 and quantization data B1, interpolation data C0.25 based on quantization data C0 and interpolation data C0.5, and interpolation data C0.75 based on interpolation data C0.5 and quantization data C1. Then, as time-series data, the control circuit 51 can use 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, and quantized data A1, B1, C1, ..., AK, BK, CK. Note that the memory 55 can store the interpolated data A0.5, A1.5, B0.5, B1.5, C0.5, C1.5 in the first location. Furthermore, the memory 55 can store the interpolated data A0.25, A0.75, B0.25, B0.75, C0.25, C0.75 in the first location.

[0114] In the first embodiment, drive waveform A is provided for discharging large droplets, drive waveform B is provided for discharging intermediate droplets, and drive waveform C is provided for discharging large droplets. However, there are no limitations on this. Drive waveform C can also be provided for discharging small droplets. Furthermore, drive waveform D can exist. Drive waveform D is provided for discharging ink droplets larger than large droplets. In other words, the number of drive waveform types is not limited to three; it can be four or two. If four types of drive waveforms are used, then for a print job, the time-division multiplexed signal is configured with four types of analog signals without changing the type of analog signal. For a period from when the time-division multiplexed signal rises in one discharge drive cycle until it falls, the time-division multiplexed signal is configured with four types of analog signals, and the type of analog signal also remains unchanged. Furthermore, if two types of drive waveforms are used, then for a print job, the time-division multiplexed signal is configured with two types of analog signals without changing the type of analog signal. Regarding the period from the rise of the time-division multiplexed signal in one emission drive cycle until the fall of the time-division multiplexed signal, the time-division multiplexed signal is configured with two types of analog signals and the type of analog signals does not change.

[0115] In the first embodiment, drive waveforms A, B, and C are used for printing. However, there are no limitations on this. Drive waveforms A, B, and C can also be used for flashing processing (S7). In other words, the time-division multiplexed signal includes three types of drive waveforms for performing flashing processing (S7) by discharging ink via nozzle 80. After this, drive waveform signals Pa, Pb, and Pc are separated from the time-division multiplexed signal according to a predetermined sampling frequency. Subsequently, actuator 88 is driven by any one of drive waveform signals Pa, Pb, and Pc. The printing device 1 is able to discharge ink to perform three types of flashing processing (S7) by using only one type of time-division multiplexed signal. In this case, the ink discharge performed for the three flashing processes (S7) includes a first flashing process in which the number of ejected ink droplets is a predetermined number, a second flashing process in which the number of ejected ink droplets is greater than the number of the first flashing process, and a third flashing process in which the number of ejected ink droplets is greater than the number of the second flashing process. Note that for the ink emission performed for the three flashing processes (S7), the number of ink droplets ejected can be the same, and the droplet sizes can be different. The size of the ink droplets in the second flashing process is larger than that in the first flashing process. Furthermore, the size of the ink droplets in the third flashing process is larger than that in the second flashing process.

[0116] In the first embodiment, drive waveforms A, B, and C are provided to cause the piezoelectric element 83 to deform, the vibrating plate 82 to vibrate, and the ink present in the pressure chamber 81 to be discharged via the nozzle 80 after the ink is allowed to pass through the descender according to the vibration of the vibrating plate 82. However, there are no limitations on this. For example, the following configuration is also available. That is, drive waveform A is provided to cause the ink present in the pressure chamber 81 to be discharged via the nozzle 80 after the ink is allowed to pass through the descender. However, drive waveform C is provided to cause the piezoelectric element 83 to deform and the vibrating plate 82 to vibrate, but drive waveform C is not provided to cause the ink present in the pressure chamber 81 to be discharged via the nozzle 80 after the ink is allowed to pass through the descender. In other words, drive waveform C is provided to perform non-discharge flashing processing. In particular, the piezoelectric element 83 deforms slightly. Then, the surface (meniscus) of the ink oscillates without discharging ink. Therefore, the time-division multiplexed signal includes two types of drive waveforms for discharging ink via the nozzle 80 and one type of drive waveform for oscillating the surface (meniscus) of the ink without discharging ink. Following this, the drive waveform signals Pa, Pb, and Pc are separated from the time-division multiplexed signal using a predetermined sampling frequency. Subsequently, the actuator 88 is driven by any one of the drive waveform signals Pa, Pb, and Pc. The printing device 1 can perform two ink emissions and one ink surface (meniscus) oscillation using, for example, only one type of time-division multiplexed signal. Furthermore, for example, the printing device 1 can perform two ink emissions for scintillation processing (S7) and one ink surface (meniscus) oscillation for non-emission scintillation processing (S10) using only one type of time-division multiplexed signal. In this case, the two ink emissions for scintillation processing (S7) include a first scintillation process in which the number of ejected ink droplets is a predetermined number, and a second scintillation process in which the number of ejected ink droplets is greater than the number in the first scintillation process. Note that in the two ink emissions for scintillation processing (S7), the number of ejected ink droplets can be the same, and the droplet sizes can be different from each other. In the second scintillation process, the droplet size is larger than the size in the first scintillation process.

[0117] Furthermore, for example, drive waveform A is provided to discharge ink present in pressure chamber 81 via nozzle 80 after ink is allowed to pass through the descender. However, drive waveforms B and C are provided to perform non-discharge scintillation processing. Specifically, piezoelectric component 83 is slightly deformed. Then, the ink surface (meniscus) oscillates without discharging ink. Therefore, the time-division multiplexed signal includes one type of drive waveform for discharging ink via nozzle 80 and two types of drive waveforms for oscillating the ink surface (meniscus) without discharging ink. After this, drive waveform signals Pa, Pb, and Pc are separated from the time-division multiplexed signal by using a predetermined sampling frequency. Actuator 88 is driven by any one of drive waveform signals Pa, Pb, and Pc. Printing device 1 can perform one type of ink discharge and two types of ink surface (meniscus) oscillation by using only one type of time-division multiplexed signal. For example, printing device 1 can perform one ink emission by using only one type of time-division multiplexing signal, thereby suppressing the increase of ink viscosity near the nozzle by ink surface (meniscus) oscillation, and maintaining a constant temperature of the ink near the nozzle by ink surface (meniscus) oscillation. Furthermore, for example, printing device 1 can perform one ink emission for scintillation processing (S7) and two types of ink surface (meniscus) oscillation for non-emission scintillation processing (S10) by using only one type of time-division multiplexing signal. In this case, the two types of ink surface (meniscus) oscillation for non-emission scintillation processing (S10) include a first non-emission scintillation process in which the number of surface (meniscus) oscillations is a predetermined number, and a second non-emission scintillation process in which the number of surface (meniscus) oscillations is greater than the number in the first non-emission scintillation process. Note that in the two types of ink surface (meniscus) oscillation for non-emission scintillation processing (S10), the number of surface (meniscus) oscillations can be the same, and the intensity of the surface (meniscus) oscillations can be different from each other. In the second non-emission scintillation process, the intensity of the surface (meniscus) oscillation is stronger than that in the first non-emission scintillation process.

[0118] Furthermore, drive waveforms A, B, and C are provided for implementing non-emission scintillation processing. Specifically, the piezoelectric component 83 deforms slightly. Then, the ink surface (meniscus) oscillates without discharging ink. Therefore, the time-division multiplexed signal includes three types of drive waveforms for oscillating the ink surface (meniscus) without discharging ink. After this, drive waveform signals Pa, Pb, and Pc are separated from the time-division multiplexed signal using a predetermined sampling frequency. The actuator 88 is driven by any one of the drive waveform signals Pa, Pb, and Pc. That is, the printing device 1 can implement three types of ink surface (meniscus) oscillation. For example, the printing device 1 can suppress a slight increase in ink viscosity near the nozzle by using one type of time-division multiplexed signal to suppress a severe increase in ink viscosity near the nozzle by using a higher degree of ink surface (meniscus) oscillation, and maintain a constant temperature of the ink near the nozzle by using ink surface (meniscus) oscillation.

[0119] It should be understood that the embodiments disclosed herein are exemplary in every respect and are not limiting. The technical features described in the various embodiments can be combined with each other. The scope of the invention is intended to include all modifications or alterations included in the claims and all scopes equivalent to the claims.

[0120] List of reference numerals

[0121] 1: Printing equipment; 50: Controller; 51: Control circuit; 52: D / A converter; 53: Amplifier; 530: Digital amplifier; 54: Switch group; 55: Memory; 56: Second switch control unit; 57: Third switch control unit; 58: Sample and hold unit; 70: Amplitude information generation circuit; 71: Voltage determination circuit; 72: Variable voltage power supply.

Claims

1. A head comprising: a nozzle configured to discharge a liquid by an energy application element; a multiplexer configured to generate a time division multiplexed signal in which, a third portion that is a part of a second drive waveform different from a first drive waveform is arranged 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 arranged between the third portion and a fourth portion that is a part of the second drive waveform, the time division multiplexed signal is capable of transmitting the first data and the second data via a single signal line; and a separator configured to separate a first drive waveform signal representing the first drive waveform or a second drive waveform signal representing the second drive waveform from the time division multiplexed signal generated by the multiplexer, wherein: the energy application element is configured to be driven by the first drive waveform signal or the second drive waveform signal separated by the separator; the first data has a plurality of quantized data values, and the second data has a plurality of quantized data values; the multiplexer includes: a control circuit; a memory configured to store the first data and the second data; a digital-to-analog converter configured to convert the plurality of quantized data values of the first data and the plurality of quantized data values of the second data into an analog signal; and an amplifier configured to amplify the analog signal of the digital-to-analog converter; the control circuit is configured to read the plurality of quantized data values of the first data and the plurality of quantized data values of the second data from the memory, and transmit the plurality of quantized data values of the first data and the plurality of quantized data values of the second data while arranging the plurality of quantized data values of the first data and the plurality of quantized data values of the second data in a time series to generate the time division multiplexed signal; the control circuit is configured to input the plurality of quantized data values of the first data and the plurality of quantized data values of the second data into the digital-to-analog converter; the digital-to-analog converter is configured to output the analog signal to the amplifier; the amplifier is configured to output the analog signal to the separator; and the separator is configured to separate the first drive waveform signal or the second drive waveform signal from the analog signal amplified by the amplifier.

2. The head according to claim 1, wherein: the separator is configured to separate the first drive waveform signal or the second drive waveform signal according to a sampling frequency that is not less than a resonance frequency of the head.

3. The head according to claim 2, further comprising: a pressure chamber configured to accommodate the liquid, wherein: the resonance frequency of the head is a resonance frequency provided in a case where the pressure chamber is filled with the liquid.

4. The head according to claim 2, further comprising: a pressure chamber configured to accommodate the liquid, wherein: the resonance frequency of the head is a resonance frequency provided in a case where the pressure chamber is not filled with the liquid.

5. The head according to any one of claims 1 to 4, wherein: the separator includes a switch configured such that the time-division multiplexed signal is input into the switch; a switch control signal for opening and closing the switch and a synchronization signal indicating an opening-closing timing are input into the switch; and the switch is configured to be opened and closed based on the switch control signal and the synchronization signal to separate the first drive waveform signal or the second drive waveform signal from the time-division multiplexed signal.

6. The head according to claim 5, further comprising: a switch control circuit, wherein: the switch control circuit is configured to open and close the switch based on the switch control signal and the synchronization signal.

7. The head according to claim 1, wherein: the multiplexer includes: the amplifier configured to amplify the time-division multiplexed signal; amplitude information generation circuitry configured to generate amplitude information of the time-division multiplexed signal; a voltage variable power supply configured to supply a voltage to the amplifier; and determination circuitry configured to determine a voltage having a voltage value variable based on the amplitude information generated by the amplitude information generation circuitry and lower than a maximum voltage able to be supplied by the voltage variable power supply; and the voltage variable power supply is configured to supply the voltage determined by the determination circuitry to the amplifier.

8. The head according to claim 1, wherein: the multiplexer is configured to generate the time-division multiplexed signal in which the third portion is arranged between the first portion and the second portion and the second portion is arranged between the third portion and the fourth portion after at least one of the first portion is refined, the time-division multiplexed signal being able to transmit the first data and the second data via a single signal line.

9. The head according to claim 1, wherein: the multiplexer is configured to generate the time-division multiplexed signal in which the third portion is arranged between the first portion and the second portion and the second portion is arranged between the third portion and the fourth portion after at least one of the first portion is extended, the time-division multiplexed signal being able to transmit the first data and the second data via a single signal line.

10. A printing apparatus including a head and a conveyer, wherein: the head includes: a multiplexer configured to generate a time division multiplexing signal in which a third portion that is a portion of a second drive waveform different from a first drive waveform is arranged between a first portion that is a portion of the first drive waveform and a second portion that is a portion of the first drive waveform, and the second portion is arranged between the third portion and a fourth portion that is a portion of the second drive waveform, based on at least first data representing the first drive waveform and second data representing the second drive waveform, the time division multiplexing signal being capable of transmitting the first data and the second data via a single signal line; a separator configured to separate out a first drive waveform signal representing the first drive waveform or a second drive waveform signal representing the second drive waveform from the time division multiplexing signal generated by the multiplexer; an energy application element configured to be driven by the first drive waveform signal or the second drive waveform signal separated out by the separator; and a nozzle configured to discharge a liquid by driving of the energy application element; the conveyer being configured to convey a print medium subjected to printing with the liquid discharged from the nozzle, the first data has a plurality of quantized data values, and the second data has a plurality of quantized data values; the multiplexer includes: a control circuit; a memory configured to store the first data and the second data; a digital-to-analog converter configured to convert the plurality of quantized data values of the first data and the plurality of quantized data values of the second data into an analog signal; and an amplifier configured to amplify the analog signal of the digital-to-analog converter; the control circuit is configured to read the plurality of quantized data values of the first data and the plurality of quantized data values of the second data from the memory, and transmit the plurality of quantized data values of the first data and the plurality of quantized data values of the second data while arranging the plurality of quantized data values of the first data and the plurality of quantized data values of the second data in a time series to generate the time division multiplexing signal; the control circuit is configured to input the plurality of quantized data values of the first data and the plurality of quantized data values of the second data into the digital-to-analog converter; the digital-to-analog converter is configured to output the analog signal to the amplifier; the amplifier is configured to output the analog signal to the separator; and the separator is configured to separate the first drive waveform signal or the second drive waveform signal from the analog signal amplified by the amplifier.

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