Patent Publication Number: US-11034146-B2

Title: Liquid discharge head control circuit, liquid discharge head, and liquid discharge apparatus

Description:
The present application is based on, and claims priority from JP Application Serial Number 2018-241702, filed Dec. 25, 2018 and JP Application Serial Number 2019-036741, filed Feb. 28, 2019, the disclosures of which are hereby incorporated by reference herein in their entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a liquid discharge head control circuit, a liquid discharge head, and a liquid discharge apparatus. 
     2. Related Art 
     It is known that a piezoelectric element is used for an ink jet printer that prints an image or a document by discharging an ink. The piezoelectric element is provided to correspond to each of a plurality of nozzles in a print head (liquid discharge head). A predetermined amount of an ink (liquid) is discharged from the nozzle at a predetermined timing by driving the piezoelectric element in accordance with a driving signal. Thus, a dot is formed on a medium. 
     For example, JP-A-2017-114020 discloses a liquid discharge apparatus as follows. The liquid discharge apparatus selects a driving signal to be supplied to each of a plurality of piezoelectric elements based on a print data signal synchronized with a clock signal. The liquid discharge apparatus supplies the selected driving signal to each of the plurality of piezoelectric elements in a period defined by a change signal and a latch signal, and thus a predetermined amount of an ink is discharged from the nozzle corresponding to each of the plurality of piezoelectric elements at a predetermined timing. 
     However, the number of nozzles in the print head increases with a request for higher speed and higher definition of printing in the recent liquid discharge apparatus. Therefore, it is required to increase the propagation speed of various control signals such as a clock signal, a print data signal, a change signal, and a latch signal supplied to the print head. As a result, it is required to further reduce distortion of a waveform occurring in the control signal. 
     SUMMARY 
     According to an aspect of the present disclosure, a liquid discharge head control circuit controls an operation of a liquid discharge head that discharges a liquid from a nozzle. The liquid discharge head includes a driving element that drives based on a driving signal to discharge the liquid from the nozzle, a driving signal selection circuit that controls a supply of the driving signal to the driving element based on a first control signal, a restoration circuit that restores a pair of first differential signals to the first control signal, a first terminal electrically coupled to the driving signal selection circuit, and a second terminal, a third terminal, a fourth terminal, and a fifth terminal which are electrically coupled to the restoration circuit. The liquid discharge head control circuit includes a conversion circuit that converts a first base control signal being a base of the first control signal into the pair of first differential signals, a first wiring which is electrically coupled to the first terminal and is used for propagating a first reference voltage signal to be supplied to the driving signal selection circuit, a second wiring which is electrically coupled to the second terminal and is used for propagating a second reference voltage signal to be supplied to the restoration circuit, a third wiring which is electrically coupled to the third terminal and is used for propagating the second reference voltage signal to be supplied to the restoration circuit, a fourth wiring which is electrically coupled to the fourth terminal and is used for propagating one signal of the pair of first differential signals, a fifth wiring which is electrically coupled to the fifth terminal and is used for propagating the other signal of the pair of first differential signals, and a driving signal output circuit that outputs the driving signal. The fourth wiring and the fifth wiring are arranged side by side. In a direction in which the fourth wiring and the fifth wiring are arranged, the fourth wiring and the second wiring are located to be adjacent to each other, the fifth wiring and the third wiring are located to be adjacent to each other, and the fourth wiring and the fifth wiring are located between the second wiring and the third wiring. 
     According to another aspect of the present disclosure, a liquid discharge head control circuit controls an operation of a liquid discharge head that discharges a liquid from a nozzle. The liquid discharge head includes a driving element that drives based on a driving signal to discharge the liquid from the nozzle, a driving signal selection circuit that controls a supply of the driving signal to the driving element based on a first control signal, a restoration circuit that restores a pair of first differential signals to the first control signal, a first terminal electrically coupled to the driving signal selection circuit, and a second terminal, a third terminal, a fourth terminal, and a fifth terminal which are electrically coupled to the restoration circuit. The liquid discharge head control circuit includes a conversion circuit that converts a first base control signal being a base of the first control signal into the pair of first differential signals, a first wiring which is electrically coupled to the first terminal and is used for propagating a first reference voltage signal to be supplied to the driving signal selection circuit, a second wiring which is electrically coupled to the second terminal and is used for propagating a second reference voltage signal to be supplied to the restoration circuit, a third wiring which is electrically coupled to the third terminal and is used for propagating the second reference voltage signal to be supplied to the restoration circuit, a fourth wiring which is electrically coupled to the fourth terminal and is used for propagating one signal of the pair of first differential signals, a fifth wiring which is electrically coupled to the fifth terminal and is used for propagating the other signal of the pair of first differential signals, and a driving signal output circuit that outputs the driving signal. The fourth wiring and the fifth wiring are arranged side by side. In a direction intersecting with a direction in which the fourth wiring and the fifth wiring are arranged, the second wiring is located to overlap the fourth wiring, and the third wiring is located to overlap the fifth wiring. 
     In the liquid discharge head control circuit, the first base control signal may be a base clock signal being a base of a clock signal. 
     In the liquid discharge head control circuit, the first base control signal may be a base print data signal being a base of a print data signal for defining a waveform selection of the driving signal. 
     In the liquid discharge head control circuit, the liquid discharge head may further include a sixth terminal electrically coupled to the driving signal selection circuit, and a seventh terminal electrically coupled to the restoration circuit. The liquid discharge head control circuit may further include a sixth wiring which is electrically coupled to the sixth terminal and is used for propagating the first reference voltage signal to be supplied to the driving signal selection circuit, and a seventh wiring which is electrically coupled to the seventh terminal and is used for propagating a second control signal for defining a timing of the supply of the driving signal to the driving element. In a direction intersecting with a direction in which the fourth wiring and the fifth wiring are arranged, the seventh wiring may be located to be adjacent to the first wiring and the sixth wiring. 
     According to still another aspect of the present disclosure, a liquid discharge head includes a driving element that drives based on a driving signal to discharge a liquid from a nozzle, a driving signal selection circuit that controls a supply of the driving signal to the driving element based on a first control signal, a restoration circuit that restores a pair of first differential signals to the first control signal, a first terminal electrically coupled to the driving signal selection circuit, and a second terminal, a third terminal, a fourth terminal, and a fifth terminal which are electrically coupled to the restoration circuit. A first reference voltage signal to be supplied to the driving signal selection circuit is input to the first terminal. A second reference voltage signal to be supplied to the restoration circuit is input to the second terminal. The second reference voltage signal to be supplied to the restoration circuit is input to the third terminal. One signal of the pair of first differential signals to be supplied to the restoration circuit is input to the fourth terminal. The other signal of the pair of first differential signals to be supplied to the restoration circuit is input to the fifth terminal. The fourth terminal and the fifth terminal are arranged side by side. In a direction in which the fourth terminal and the fifth terminal are arranged, the fourth terminal and the second terminal are located to be adjacent to each other, the fifth terminal and the third terminal are located to be adjacent to each other, and the fourth terminal and the fifth terminal are located between the second terminal and the third terminal. 
     According to still another aspect of the present disclosure, a liquid discharge head includes a driving element that drives based on a driving signal to discharge a liquid from a nozzle, a driving signal selection circuit that controls a supply of the driving signal to the driving element based on a first control signal, a restoration circuit that restores a pair of first differential signals to the first control signal, a first terminal electrically coupled to the driving signal selection circuit, and a second terminal, a third terminal, a fourth terminal, and a fifth terminal which are electrically coupled to the restoration circuit. A first reference voltage signal to be supplied to the driving signal selection circuit is input to the first terminal. A second reference voltage signal to be supplied to the restoration circuit is input to the second terminal. The second reference voltage signal to be supplied to the restoration circuit is input to the third terminal. One signal of the pair of first differential signals to be supplied to the restoration circuit is input to the fourth terminal. The other signal of the pair of first differential signals to be supplied to the restoration circuit is input to the fifth terminal. The fourth terminal and the fifth terminal are arranged side by side. In a direction intersecting with a direction in which the fourth terminal and the fifth terminal are arranged, the second terminal is located to overlap the fourth terminal, and the third terminal is located to overlap the fifth terminal. 
     In the liquid discharge head, the first control signal may be a clock signal. 
     In the liquid discharge head, the first control signal may be a print data signal for defining a waveform selection of the driving signal. 
     The liquid discharge head may further include a sixth terminal electrically coupled to the driving signal selection circuit, and a seventh terminal electrically coupled to the restoration circuit. The first reference voltage signal to be supplied to the driving signal selection circuit may be input to the sixth terminal. A second control signal for defining a timing of the supply of the driving signal to the driving element may be input to the seventh terminal. In a direction intersecting with the direction in which the fourth terminal and the fifth terminal are arranged, the seventh terminal may be located to be adjacent to the first terminal and the sixth terminal. 
     According to still another aspect of the present disclosure, a liquid discharge apparatus includes a liquid discharge head that discharges a liquid from a nozzle, and a liquid discharge head control circuit that controls an operation of the liquid discharge head. The liquid discharge head includes a driving element that drives based on a driving signal to discharge the liquid from the nozzle, a driving signal selection circuit that controls a supply of the driving signal to the driving element based on a first control signal, a restoration circuit that restores a pair of first differential signals to the first control signal, a first terminal electrically coupled to the driving signal selection circuit, and a second terminal, a third terminal, a fourth terminal, and a fifth terminal which are electrically coupled to the restoration circuit. The liquid discharge head control circuit includes a conversion circuit that converts a first base control signal being a base of the first control signal into the pair of first differential signals, a first wiring which is electrically coupled to the first terminal and is used for propagating a first reference voltage signal to be supplied to the driving signal selection circuit, a second wiring which is electrically coupled to the second terminal and is used for propagating a second reference voltage signal to be supplied to the restoration circuit, a third wiring which is electrically coupled to the third terminal and is used for propagating the second reference voltage signal to be supplied to the restoration circuit, a fourth wiring which is electrically coupled to the fourth terminal and is used for propagating one signal of the pair of first differential signals, a fifth wiring which is electrically coupled to the fifth terminal and is used for propagating the other signal of the pair of first differential signals, and a driving signal output circuit that outputs the driving signal. The first wiring and the first terminal are electrically in contact with each other at a first contact portion. The second wiring and the second terminal are electrically in contact with each other at a second contact portion. The third wiring and the third terminal are electrically in contact with each other at a third contact portion. The fourth wiring and the fourth terminal are electrically in contact with each other at a fourth contact portion. The fifth wiring and the fifth terminal are electrically in contact with each other at a fifth contact portion. The fourth contact portion and the fifth contact portion are located to be arranged. In a direction in which the fourth contact portion and the fifth contact portion are arranged, the fourth contact portion and the second contact portion are located to be adjacent to each other, the fifth contact portion and the third contact portion are located to be adjacent to each other, and the fourth contact portion and the fifth contact portion are located between the second contact portion and the third contact portion. 
     According to still another aspect of the present disclosure, a liquid discharge apparatus includes a liquid discharge head that discharges a liquid from a nozzle, and a liquid discharge head control circuit that controls an operation of the liquid discharge head. The liquid discharge head includes a driving element that drives based on a driving signal to discharge the liquid from the nozzle, a driving signal selection circuit that controls a supply of the driving signal to the driving element based on a first control signal, a restoration circuit that restores a pair of first differential signals to the first control signal, a first terminal electrically coupled to the driving signal selection circuit, and a second terminal, a third terminal, a fourth terminal, and a fifth terminal which are electrically coupled to the restoration circuit. The liquid discharge head control circuit includes a conversion circuit that converts a first base control signal being a base of the first control signal into the pair of first differential signals, a first wiring which is electrically coupled to the first terminal and is used for propagating a first reference voltage signal to be supplied to the driving signal selection circuit, a second wiring which is electrically coupled to the second terminal and is used for propagating a second reference voltage signal to be supplied to the restoration circuit, a third wiring which is electrically coupled to the third terminal and is used for propagating the second reference voltage signal to be supplied to the restoration circuit, a fourth wiring which is electrically coupled to the fourth terminal and is used for propagating one signal of the pair of first differential signals, a fifth wiring which is electrically coupled to the fifth terminal and is used for propagating the other signal of the pair of first differential signals, and a driving signal output circuit that outputs the driving signal. The first wiring and the first terminal are electrically in contact with each other at a first contact portion. The second wiring and the second terminal are electrically in contact with each other at a second contact portion. The third wiring and the third terminal are electrically in contact with each other at a third contact portion. The fourth wiring and the fourth terminal are electrically in contact with each other at a fourth contact portion. The fifth wiring and the fifth terminal are electrically in contact with each other at a fifth contact portion. The fourth contact portion and the fifth contact portion are located to be arranged. In a direction intersecting with a direction in which the fourth contact portion and the fifth contact portion are arranged, the second contact portion is located to overlap the fourth contact portion, and the third contact portion is located to overlap the fifth contact portion. 
     In the liquid discharge apparatus, the first base control signal may be a base clock signal being a base of a clock signal. 
     In the liquid discharge apparatus, the first base control signal may be a base print data signal being a base of a print data signal for defining a waveform selection of the driving signal. 
     In the liquid discharge apparatus, the liquid discharge head may further include a sixth terminal electrically coupled to the driving signal selection circuit, and a seventh terminal electrically coupled to the restoration circuit. The liquid discharge head control circuit may further include a sixth wiring which is electrically coupled to the sixth terminal and is used for propagating the first reference voltage signal to be supplied to the driving signal selection circuit, and a seventh wiring which is electrically coupled to the seventh terminal and is used for propagating a second control signal for defining a timing of the supply of the driving signal to the driving element. The sixth wiring and the sixth terminal may be electrically in contact with each other at a sixth contact portion. The seventh wiring and the seventh terminal may be electrically in contact with each other at a seventh contact portion. In a direction intersecting with a direction in which the fourth wiring and the fifth wiring are arranged, the seventh wiring may be located to be adjacent to the first wiring and the sixth wiring. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating an overall configuration of a liquid discharge apparatus. 
         FIG. 2  is a block diagram illustrating an electrical configuration of the liquid discharge apparatus. 
         FIG. 3  is a diagram illustrating an example of driving signals COMA and COMB. 
         FIG. 4  is a diagram illustrating an example of a driving signal VOUT. 
         FIG. 5  is a diagram illustrating a configuration of a driving signal selection circuit. 
         FIG. 6  is a diagram illustrating decoding contents in a decoder. 
         FIG. 7  is a diagram illustrating a configuration of a selection circuit corresponding to one discharge section. 
         FIG. 8  is a diagram illustrating an operation of the driving signal selection circuit. 
         FIG. 9  is a schematic diagram illustrating an internal configuration of the liquid discharge apparatus. 
         FIG. 10  is a diagram illustrating a configuration of a cable. 
         FIG. 11  is a perspective view illustrating a configuration of a liquid discharge head. 
         FIG. 12  is a plan view illustrating a configuration of an ink discharge surface. 
         FIG. 13  is a diagram illustrating an overall configuration of one of a plurality of discharge sections. 
         FIG. 14  is a plan view when a head substrate is viewed from a surface. 
         FIG. 15  is a diagram illustrating a configuration of a connector. 
         FIG. 16  is a diagram illustrating a specific example when the cable is attached to the connector. 
         FIG. 17  is a diagram illustrating details of a signal which is propagated in a cable  19   a  and is input to a liquid discharge head through a connector  350   a.    
         FIG. 18  is a diagram illustrating details of a signal which is propagated in a cable  19   b  and is input to the liquid discharge head through a connector  350   b.    
         FIG. 19  is a diagram illustrating details of a signal which is propagated in a cable  19   c  and is input to the liquid discharge head through a connector  350   c.    
         FIG. 20  is a diagram illustrating details of a signal which is propagated in a cable  19   d  and is input to the liquid discharge head through a connector  350   d.    
         FIG. 21  is a diagram illustrating details of a signal which is propagated in a cable  19   e  and is input to the liquid discharge head through a connector  350   e.    
         FIG. 22  is a diagram illustrating details of a signal which is propagated in a cable  19   f  and is input to the liquid discharge head through a connector  350   f.    
         FIG. 23  is a diagram illustrating details of a signal which is propagated in a cable  19   g  and is input to the liquid discharge head through a connector  350   g.    
         FIG. 24  is a diagram illustrating details of a signal which is propagated in a cable  19   h  and is input to the liquid discharge head through a connector  350   h.    
         FIG. 25  is a diagram illustrating details of a signal which is propagated in a cable  19   b  and is input to a liquid discharge head through a connector  350   b  according to a second embodiment. 
         FIG. 26  is a diagram illustrating details of a signal which is propagated in a cable  19   a  and is input to a liquid discharge head through a connector  350   a  according to a third embodiment. 
         FIG. 27  is a diagram illustrating details of a signal which is propagated in a cable  19   b  and is input to the liquid discharge head through a connector  350   b  in the third embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, preferred embodiments of the present disclosure will be described with reference to the drawings. The drawings are used for easy descriptions. The embodiments described below do not limit the scope of the present disclosure described in the claims. All components described later are not necessarily essential constituent elements of the present disclosure. 
     1. First Embodiment 
     1.1. Outline of Liquid Discharge Apparatus 
       FIG. 1  is a diagram illustrating an overall configuration of a liquid discharge apparatus  1 . The liquid discharge apparatus  1  is a serial printing type ink jet printer that forms an image on a medium P in a manner that a carriage  20  discharges an ink to the transported medium P with reciprocating. In the carriage  20 , a liquid discharge head  21  that discharges the ink as an example of a liquid is mounted. In the following descriptions, descriptions will be made on the assumption that a direction in which the carriage  20  moves is an X-direction, a direction in which the medium P is transported is a Y-direction, and a direction in which the ink is discharged is a Z-direction. Descriptions will be made on the assumption that the X-direction, the Y-direction, and the Z-direction are perpendicular to each other. However, the descriptions are not limited to a point that various components in the liquid discharge apparatus  1  are disposed to be perpendicular to each other. As the medium P, any printing target such as print paper, a resin film, and a cloth can be used. 
     The liquid discharge apparatus  1  includes a liquid container  2 , a control mechanism  10 , the carriage  20 , a movement mechanism  30 , and a transport mechanism  40 . 
     Plural kinds of inks to be discharged onto a medium P are stored in the liquid container  2 . As the color of the ink stored in the liquid container  2 , black, cyan, magenta, yellow, red, and gray, and the like are exemplified. As the liquid container  2  in which such an ink is stored, an ink cartridge, a bag-like ink pack formed of a flexible film, an ink tank capable of replenishing an ink, or the like is used. 
     The control mechanism  10  includes, for example, a processing circuit such as a central processing unit (CPU) or a field programmable gate array (FPGA) and a storage circuit such as a semiconductor memory. The control mechanism  10  controls elements of the liquid discharge apparatus  1 . Specifically, the control mechanism  10  generates control signals Ctrl-H, Ctrl-C, and Ctrl-T for controlling operations of various components of the liquid discharge apparatus  1 , and outputs the control signals to the corresponding components. 
     The liquid discharge head  21  is mounted in the carriage  20 . The control signal Ctrl-H including a plurality of signals is input to the liquid discharge head  21 . The liquid discharge head  21  discharges an ink supplied from the liquid container  2 , based on the control signal Ctrl-H. The liquid container  2  may be mounted in the carriage  20 . 
     The movement mechanism  30  includes a carriage motor  31  and an endless belt  32 . The control signal Ctrl-C is input to the movement mechanism  30 . The carriage motor  31  operates based on the control signal Ctrl-C. The carriage  20  is fixed to the endless belt  32 . The endless belt  32  rotates by an operation of the carriage motor  31 . Thus, the carriage  20  fixed to the endless belt  32  reciprocates in the X-direction. The control signal Ctrl-C may be converted into a signal having a more suitable format for operating the carriage motor  31  in a carriage motor driver (not illustrated). 
     The transport mechanism  40  includes a transport motor  41  and a transport roller  42 . The control signal Ctrl-T is input to the transport mechanism  40 . The transport motor  41  operates based on the control signal Ctrl-T. The transport roller  42  rotates by an operation of the transport motor  41 . A medium P is transported in the Y-direction with the rotation of the transport roller  42 . The control signal Ctrl-T may be converted into a signal having a more suitable format for operating the transport motor  41  in a transport motor driver (not illustrated). 
     As described above, the liquid discharge apparatus  1  discharges an ink from the liquid discharge head  21  mounted in the carriage  20  in the Z-direction with transport of the medium P in the Y-direction by the transport mechanism  40  and reciprocation of the carriage  20  in the X-direction by the movement mechanism  30 . Thus, the liquid discharge apparatus  1  forms a desired image on the medium P. 
     1.2. Electrical Configuration of Liquid Discharge Apparatus 
       FIG. 2  is a block diagram illustrating an electrical configuration of the liquid discharge apparatus  1 . The liquid discharge apparatus  1  includes the control mechanism  10  and the liquid discharge head  21 . Descriptions will be made on the assumption that the liquid discharge head  21  in  FIG. 2  includes n driving signal selection circuits  200 . 
     The control mechanism  10  includes a conversion circuit  70 , driving signal output circuits  50 - 1  to  50 - n , a first power source voltage output circuit  51 , a second power source voltage output circuit  52 , and a control circuit  100 . The control circuit  100  includes a processor such as a microcontroller, for example. The control circuit  100  generates and outputs data or various signals for controlling the liquid discharge apparatus  1 , based on various signals such as image data, which are input from a host computer. 
     Specifically, the control circuit  100  outputs a base clock signal oSCK, base print data signals oSI 1  to oSIn, a base latch signal oLAT, base change signals oCHa and oCHb, and base driving signals dA 1  to dAn and dB 1  to dBn, which are used for controlling the liquid discharge apparatus  1 . 
     The base clock signal oSCK, the base print data signals oSI 1  to oSIn, the base latch signal oLAT, and the base change signals oCHa and oCHb are signals being bases of a clock signal SCK, print data signals SI 1  to SIn, a latch signal LAT, and change signals CHa and CHb which are for controlling an operation of the liquid discharge head  21 . The control circuit  100  outputs the base clock signal oSCK and each of the base print data signals oSI 1  to oSIn to the conversion circuit  70 . The control circuit  100  outputs the base latch signal oLAT and each of the base change signals oCHa and oCHb to the liquid discharge head  21 . 
     The conversion circuit  70  converts a base control signal being a base of a certain signal in the control signal Ctrl-H into a pair of differential signals. Specifically, the conversion circuit  70  converts the base clock signal oSCK being the base of the clock signal SCK in the control signal Ctrl-H into a pair of differential clock signals dSCK. The conversion circuit  70  converts each of the base print data signals oSI 1  to oSIn being each of the print data signals SI 1  to SIn in the control signal Ctrl-H into a pair of differential print data signals dSI 1  to dSIn. The conversion circuit  70  outputs the differential clock signal dSCK and each of the differential print data signals dSI 1  to dSIn to the liquid discharge head  21 . 
     Here, the conversion circuit  70  performs conversion into a differential signal of a low voltage differential signaling (LVDS) transfer method, for example. A differential signal of the LVDS transfer method has an amplitude of substantially 350 mV, and thus can realize high-speed data transfer. The conversion circuit  70  may perform conversion into a differential signal of various high-speed transfer method such as a low voltage positive emitter coupled logic (LVPECL) transfer method or a current mode logic (CML) transfer method in addition to the LVDS transfer method. 
     The base driving signals dA 1  to dAn and dB 1  to dBn are digital signals and signals being bases of driving signals COMA 1  to COMAn and COMB 1  to COMBn for driving a piezoelectric element  60  as a driving element provided in the liquid discharge head  21 . The base driving signals dA 1  to dAn and dB 1  to dBn are input to the corresponding driving signal output circuits  50 - 1  to  50 - n . The following descriptions will be made on the assumption that the base driving signals dAi and dBi (i is any of 1 to n) are input to the corresponding driving signal output circuit  50 - i.    
     The driving signal output circuit  50 - i  generates the driving signal COMAi by performing D-class amplification on an analog signal obtained by performing digital-to-analog signal conversion on the input base driving signal dAi. The driving signal output circuit  50 - i  generates the driving signal COMBi by performing D-class amplification on an analog signal obtained by performing digital-to-analog signal conversion on the input base driving signal dBi. That is, the driving signal output circuit  50 - i  includes two D-class amplifier circuits which are a D-class amplifier circuit that generates the driving signal COMAi based on the base driving signal dAi and a D-class amplifier circuit that generates the driving signal COMBi based on the base driving signal dBi. The base driving signals dAi and dBi may be signals capable of defining waveforms of the driving signals COMAi and COMBi and may be analog signals. The two D-class amplifier circuit in the driving signal output circuit  50 - i  may be capable of amplifying the waveform defined by the base driving signals dAi and dBi, and may be configured with various amplifier circuits such as an A-class amplifier circuit, a B-class amplifier circuit, or an AB-class amplifier circuit. 
     The driving signal output circuit  50   i  generates and outputs a voltage VBSi indicating a reference potential of the driving signals COMAi and COMBi. For example, the voltage VBSi may be a signal having a ground potential in which a voltage value is 0 V, or may be a signal having a DC voltage in which a voltage value is 5 V, 6 V, or the like. 
     The driving signal output circuit  50 - i  outputs the driving signals COMAi and COMBi and the voltage VBSi which are generated, to the liquid discharge head  21 . Here, all of the driving signal output circuits  50 - 1  to  50 - n  have the similar configuration, and thus may be referred to as a driving signal output circuit  50  in the following descriptions. Descriptions may be made on the assumption that the base driving signals dA and dB are input to the driving signal output circuit  50 , and the driving signal output circuit  50  generates the driving signals COMA and COMB and the voltage VBS. Here, at least one of the driving signals COMA and COMB is an example of the driving signal. 
     Here, although not illustrated in  FIG. 2 , the control circuit  100  outputs the control signal Ctrl-C for controlling reciprocation of the carriage  20  (in which the liquid discharge head  21  is mounted) in the X-direction to the movement mechanism  30  illustrated in  FIG. 1 . The control circuit  100  outputs the control signal Ctrl-T for controlling transport of the medium P in the Y-direction to the transport mechanism  40  illustrated in  FIG. 1 . 
     The first power source voltage output circuit  51  generates a voltage VDD being a DC voltage having a voltage value of 3.3 V. The voltage VDD is a power source voltage of various components of the control mechanism  10  and the liquid discharge head  21 . The first power source voltage output circuit  51  may generate voltage VDD having a plurality of voltage values suitable for the various components of the control mechanism  10  and the liquid discharge head  21 . The first power source voltage output circuit  51  outputs the generated voltages VDD to the various components including the liquid discharge head  21 . 
     The second power source voltage output circuit  52  generates a voltage VHV which is a DC voltage having a voltage value which is larger than the voltage VDD and is, for example, 42 V. The voltage VHV is supplied to the driving signal output circuits  50 - 1  to  50 - n . The driving signal output circuits  50 - 1  to  50 - n  generate the driving signals COMA 1  to COMAn and COMB 1  to COMBn subjected to D-class amplification, based on the voltage VHV. The second power source voltage output circuit  52  also outputs voltage VHV to the driving signal selection circuits  200 - 1  to  200 - n  in the liquid discharge head  21 . 
     As described above, the control mechanism  10  outputs the above-described various signals and voltages to the liquid discharge head  21  as the control signal Ctrl-H for controlling the operation of the liquid discharge head  21 . The control mechanism  10  outputs ground signals GND 1  and GND 2  for defining a ground potential of the liquid discharge head  21  to the liquid discharge head  21 . 
     The liquid discharge head  21  includes a restoration circuit  130 , the driving signal selection circuits  200 - 1  to  200 - n , and a plurality of discharge sections  600 . 
     The differential clock signal dSCK, the differential print data signals dSI 1  to dSIn, the base latch signal oLAT, and the base change signals oCHa and oCHb are input to the restoration circuit  130 . The restoration circuit  130  restores the differential signal to a single-ended signal based on the input various signals. Specifically, the restoration circuit  130  restores the differential clock signal dSCK and the differential print data signals dSI 1  to dSIn to single-ended signals based on the input base latch signal oLAT and a timing defined by the base change signals oCHa and oCHb. In other words, the restoration circuit  130  restores a pair of differential clock signals dSCK to the clock signal SCK. The restoration circuit  130  restores the pair of differential print data signals dSI 1  to dSIn to the print data signals SI 1  to SIn, respectively. The restoration circuit  130  outputs the clock signal SCK and the print data signals SI 1  to SIn being the restored single-ended signals. 
     Here, the clock signal SCK is an example of a first control signal. The base clock signal oSCK being the base of the clock signal SCK is an example of a first base control signal. The pair of differential clock signal dSCKs obtained by converting the base clock signal oSCK into a pair of differential signals are an example of a pair of first differential signals. 
     The base latch signal oLAT and the base change signals oCHa and oCHb input to the restoration circuit  130  are used for defining a timing for restoring the pair of differential signals to a single-ended signal, and then are output from the restoration circuit  130  as the latch signal LAT and the change signals CHa and CHb. Here, in a case where delay occurring in the restoration circuit  130  is not added, the base latch signal oLAT and the base change signals oCHa and oCHb input to the restoration circuit  130  may have the same waveforms as the waveforms of the latch signal LAT and the change signals CHa and CHb output from the restoration circuit  130 . 
     As described above, if the single-ended signal for controlling the liquid discharge apparatus  1  is input to the restoration circuit  130  in addition to the differential signal being a signal as a restoration target, it is possible to reduce a concern that a signal delay occurs between a single-ended signal restored by the restoration circuit  130  and a single-ended signal which is not restored by the restoration circuit  130 . 
     The voltages VHV and VDD, the clock signal SCK, the latch signal LAT, the change signals CHa and CHb, and the ground signal GND 1  are commonly input to each of the driving signal selection circuits  200 - 1  to  200 - n . The driving signals COMA 1  to COMAn and COMB 1  to COMBn and the print data signals SI 1  to SIn are input to the driving signal selection circuits  200 - 1  to  200 - n , respectively. The driving signal selection circuits  200 - 1  to  200 - n  select or do not select the corresponding driving signals COMA 1  to COMAn and COMB 1  to COMBn so as to generate driving signals VOUT 1  to VOUTn and supply the driving signals VOUT 1  to VOUTn to one end of the piezoelectric element  60  in the plurality of corresponding discharge sections  600 . In other words, the driving signal selection circuits  200 - 1  to  200 - n  control a supply of the driving signals COMA 1  to COMAn and COMB 1  to COMBn to the piezoelectric element  60  based on the clock signal SCK, the print data signals SI 1  to SIn, the latch signal LAT, and the change signals CHa and CHb, respectively. In this case, voltages VBS 1  to VBSn are supplied to the other end of the piezoelectric element  60 . The piezoelectric element  60  performs displacement based on the driving signals VOUT 1  to VOUTn and the voltages VBS 1  to VBSn, and thus an ink having an amount depending on the displacement is discharged from the discharge section  600 . That is, the piezoelectric element  60  drives based on the driving signals COMA and COMB to discharge a liquid from the nozzle. 
     Here, all of the driving signal selection circuits  200 - 1  to  200 - n  have the similar configuration, and thus may be referred to as a driving signal selection circuit  200  in the following descriptions. Descriptions may be made on the assumption that the driving signal selection circuit  200  selects or does not select the driving signals COMA and COMB to generate the driving signal VOUT. 
     Each of the restoration circuit  130  and the driving signal selection circuit  200  in the liquid discharge head  21  may be configured by one or a plurality of integrated circuits (ICs). The restoration circuit  130  and the driving signal selection circuit  200  may be configured in one integrated circuit. 
     1.3. Example of Waveform of Driving Signal 
     Here, an example of the waveforms of the driving signals COMA and COMB generated by the driving signal output circuit  50  and an example of the waveform of the driving signal VOUT supplied to the piezoelectric element  60  will be described with reference to  FIGS. 3 and 4 . 
       FIG. 3  is a diagram illustrating an example of the waveforms of the driving signals COMA and COMB. As illustrated in  FIG. 3 , the driving signal COMA has a waveform in which a trapezoid waveform Adp 1  and a trapezoid waveform Adp 2  are made continuous. The trapezoid waveform Adp 1  is disposed in a period T 1  from when the latch signal LAT rises until the change signal CHa rises. The trapezoid waveform Adp 2  is disposed in a period T 2  from when the change signal CHa rises until the latch signal LAT rises the next time. In the embodiment, the trapezoid waveform Adp 1  and the trapezoid waveform Adp 2  are substantially the same as each other. When each of the trapezoid waveforms Adp 1  and Adp 2  is supplied to one end of the piezoelectric element  60 , the medium amount of the ink is discharged from the discharge section  600  corresponding to this piezoelectric element  60 . 
     The driving signal COMB has a waveform in which a trapezoid waveform Bdp 1  and a trapezoid waveform Bdp 2  are made continuous. The trapezoid waveform Bdp 1  is disposed in a period T 3  from when the latch signal LAT rises until the change signal CHb rises. The trapezoid waveform Bdp 2  is disposed in a period T 4  from when the change signal CHb rises until the latch signal LAT rises the next time. In the embodiment, the trapezoid waveform Bdp 1  and the trapezoid waveform Bdp 2  are different from each other. 
     Among the waveforms, the trapezoid waveform Bdp 1  is a waveform for finely vibrating the ink in the vicinity of a nozzle opening portion of the discharge section  600  to prevent an increase of ink viscosity. When the trapezoid waveform Bdp 1  is supplied to one end of the piezoelectric element  60 , the ink is not discharged from the discharge section  600  corresponding to this piezoelectric element  60 . The trapezoid waveform Bdp 2  is different from the trapezoid waveforms Adp 1  and Adp 2  and the trapezoid waveform Bdp 1 . When the trapezoid waveform Bdp 2  is supplied to one end of the piezoelectric element  60 , an ink having an amount which is smaller than the medium amount is discharged from the discharge section  600  corresponding to this piezoelectric element  60 . 
     As described above, the periods T 1  to T 4  and a period Ta which are timings for supplying the driving signals COMA and COMB to the piezoelectric element  60  are defined based on the latch signal LAT and the change signals CHa and CHb. Here, all voltages at a start timing and an end timing of each of the trapezoid waveforms Adp 1 , Adp 2 , Bdp 1 , and Bdp 2  are common and a voltage Vc. That is, each of the trapezoid waveforms Adp 1 , Adp 2 , Bdp 1 , and Bdp 2  is a waveform which starts at the voltage Vc and ends at the voltage Vc. Each of the driving signals COMA and COMB is described to be a signal having a waveform in which two trapezoid waveforms are continuous in the period Ta, but may be a signal having a waveform in which three trapezoid waveforms or more are continuous in the period Ta. 
       FIG. 4  is a diagram illustrating an example of the waveform of the driving signal VOUT corresponding to each of “a large dot”, “a medium dot”, “a small dot”, and “non-recording”. As illustrated in  FIG. 4 , the driving signal VOUT corresponding to “the large dot” has a waveform in which the trapezoid waveform Adp 1  and the trapezoid waveform Adp 2  are continuous in the period Ta. When the driving signal VOUT is supplied to the one end of the piezoelectric element  60 , the medium amount of the ink is discharged two times from the discharge section  600  corresponding to this piezoelectric element  60 , in the period Ta. Thus, the inks are landed on the medium P and are coalesced, and thereby a large dot is formed on the medium P. 
     The driving signal VOUT corresponding to “the medium dot” has a waveform in which the trapezoid waveform Adp 1  and the trapezoid waveform Bdp 2  are continuous in the period Ta. When the driving signal VOUT is supplied to the one end of the piezoelectric element  60 , the medium amount of the ink and the small amount of the ink are discharged from the discharge section  600  corresponding to this piezoelectric element  60 , in the period Ta. Thus, the inks are landed on the medium P and are coalesced, and thereby a medium dot is formed on the medium P. 
     The driving signal VOUT corresponding to “the small dot” has the trapezoid waveform Bdp 2  in the period Ta. When the driving signal VOUT is supplied to the one end of the piezoelectric element  60 , the small amount of the ink is discharged from the discharge section  600  corresponding to this piezoelectric element  60 , in the period Ta. 
     Thus, the inks are landed on the medium P, and thereby a small dot is formed on the medium P. 
     The driving signal VOUT corresponding to “non-recording” has the trapezoid waveform Bdp 1  in the period Ta. When the driving signal VOUT is supplied to the one end of the piezoelectric element  60 , in the period Ta, only the ink in the vicinity of the nozzle opening portion of the discharge section  600  corresponding to this piezoelectric element  60  finely vibrates, and the ink is not discharged. Therefore, the ink is not landed on the medium P, and a dot is not formed on the medium P. 
     Here, when any of the driving signals COMA and COMB is not selected as the driving signal VOUT, the voltage Vc just before is held at the one end of the piezoelectric element  60  by a capacitive component of the piezoelectric element  60 . That is, when neither driving signals COMA nor COMB is selected, the voltage Vc is supplied to the piezoelectric element  60  as the driving signal VOUT. 
     The driving signals COMA and COMB and the driving signal VOUT illustrated in  FIGS. 3 and 4  are just examples. Signals having various combinations of waveforms may be used in accordance with a moving speed of the carriage  20  in which the liquid discharge head  21  is mounted, the physical properties of the ink to be discharged, the material of the medium P, and the like. The driving signal COMA and the driving signal COMB may be signals having a waveform in which the same trapezoid waveforms are continuous. Here, the driving signals COMA and COMB are an example of the driving signal. The driving signal VOUT generated by selecting or not selecting the waveforms of the driving signals COMA and COMB is also an example of the driving signal in a broad sense. 
     1.4. Driving Signal Selection Circuit 
     Next, a configuration and an operation of the driving signal selection circuit  200  will be described with reference to  FIGS. 5 to 8 .  FIG. 5  is a diagram illustrating a configuration of the driving signal selection circuit  200 . As illustrated in  FIG. 5 , the driving signal selection circuit  200  includes a selection control circuit  220  and a plurality of selection circuits  230 . 
     The print data signal SI, the latch signal LAT, the change signals CHa and CHb, and the clock signal SCK are input to the selection control circuit  220 . A set of a shift register (S/R)  222 , a latch circuit  224 , and a decoder  226  is provided in the selection control circuit  220  to correspond to each of the plurality of discharge sections  600 . That is, the driving signal selection circuit  200  includes sets of shift registers  222 , latch circuits  224 , and decoders  226 . The number of sets is equal to the total number m of the corresponding discharge sections  600 . 
     The print data signal SI is a signal for defining a waveform selection between the driving signal COMA and the driving signal COMB. Specifically, the print data signal SI is a signal synchronized with the clock signal SCK. The print data signal SI is a signal which has 2m bits in total and includes 2-bit print data [SIH, SIL] for selecting any of “the large dot”, “the medium dot”, “the small dot”, and “non-recording” for each of m pieces of discharge sections  600 . Regarding the print data signal SI, each 2-bit print data [SIH, SIL]which corresponds to the discharge section  600  and is included in the print data signal SI is held in the shift register  222 . In detail, the shift registers  222  from the first stage to the m-th stage, which correspond to the discharge sections  600  are cascade-coupled to each other, and the print data signal SI supplied in a serial manner is sequentially transferred to the subsequent stages in accordance with the clock signal SCK. In  FIG. 5 , in order to distinguish the shift registers  222  from each other, the shift registers  222  are described as being the first stage, the second stage, . . . , and the m-th stage in order from the upstream on which the print data signal SI is supplied. 
     Each of the m pieces of latch circuits  224  latches the 2-bit print data [SIH, SIL] held in each of the m pieces of shift registers  222 , at a rising edge of the latch signal LAT. 
     Each of the m pieces of decoders  226  decodes the 2-bit print data [SIH, SIL] latched by each of the m pieces of latch circuits  224 . The decoder  226  outputs a selection signal S 1  for each of the periods T 1  and T 2  defined by the latch signal LAT and the change signal CHa, and outputs a selection signal S 2  for each of the periods T 3  and T 4  defined by the latch signal LAT and the change signal CHb. 
       FIG. 6  is a diagram illustrating decoding contents in the decoder  226 . The decoder  226  outputs the selection signals S 1  and S 2  in accordance with the 2-bit print data [SIH, SIL] latched by the latch circuit  224 . For example, when the 2-bit print data [SIH, SIL] latched by the latch circuit  224  is [1, 0], the decoder  226  sets a logical level of the selection signal S 1  to respectively be an H level and an L level in the periods T 1  and T 2  and sets a logical level of the selection signal S 2  to respectively be an L level and an H level in the periods T 3  and T 4 . The logical levels of the selection signals S 1  and S 2  are subject to level shift to a high amplitude logic level based on the voltage VHV by a level shifter (not illustrated). 
     The selection circuits  230  are provided to correspond to the discharge sections  600 , respectively. That is, the number of selection circuits  230  of the driving signal selection circuit  200  is equal to the total number m of the corresponding discharge sections  600 . 
       FIG. 7  is a diagram illustrating a configuration of the selection circuit  230  corresponding to one discharge section  600 . As illustrated in  FIG. 7 , the selection circuit  230  includes inverters  232   a  and  232   b  being NOT circuits, and transfer gates  234   a  and  234   b.    
     The selection signal S 1  is supplied to a positive control end of the transfer gate  234   a , which is not marked with a circle, but is logically inverted by the inverter  232   a  and is supplied to a negative control end of the transfer gate  234   a , which is marked with a circle. The selection signal S 2  is supplied to a positive control end of the transfer gate  234   b , but is logically inverted by the inverter  232   b  and is supplied to a negative control end of the transfer gate  234   b.    
     The driving signal COMA is supplied to an input end of the transfer gate  234   a . The driving signal COMB is supplied to an input end of the transfer gate  234   b . Output ends of the transfer gates  234   a  and  234   b  are commonly coupled to each other, and the driving signal VOUT is output to the discharge section  600  through the commonly-coupled terminals. 
     The transfer gate  234   a  electrically connects the input end and an output end when the selection signal S 1  has an H level, and does not electrically connect the input end and the output end when the selection signal S 1  has an L level. The transfer gate  234   b  electrically connects the input end and an output end when the selection signal S 2  has an H level, and does not electrically connect the input end and the output end when the selection signal S 2  has an L level. 
     Next, an operation of the driving signal selection circuit  200  will be described with reference to  FIG. 8 .  FIG. 8  is a diagram illustrating the operation of the driving signal selection circuit  200 . The print data signal SI is serially supplied in synchronization with the clock signal SCK and is sequentially transferred into the shift registers  222  corresponding to the discharge sections  600 . If the supply of the clock signal SCK stops, the 2-bit print data [SIH, SIL] corresponding to each of the discharge sections  600  is held in each of the shift registers  222 . The print data signal SI is supplied in order of the discharge sections  600  corresponding to the m-th stage, . . . , the second stage, and the first stage of the shift registers  222 . 
     If the latch signal LAT rises, the latch circuits  224  simultaneously latch the 2-bit print data [SIH, SIL] held by the shift registers  222 . In  FIG. 8 , LT 1 , LT 2 , . . . , and LTm indicate the 2-bit print data [SIH, SIL] latched by the latch circuits  224  respectively corresponding to the first stage, the second stage, . . . , and the m-th stage of the shift registers  222 . 
     The decoder  226  outputs the logical levels of the selection signals S 1  and S 2  in each of the periods T 1 , T 2 , T 3 , and T 4  with the contents as illustrated in  FIG. 6 , in accordance with the size of a dot defined by the latched 2-bit print data [SIH, SIL]. 
     Specifically, when the print data [SIH, SIL] is [1, 1], the decoder  226  sets the selection signal S 1  to have an H level and an H level in the periods T 1  and T 2 , and sets the selection signal S 2  to have an L level and an L level in the periods T 3  and T 4 . In this case, the selection circuit  230  selects the trapezoid waveform Adp 1  included in the driving signal COMA in the period T 1 , selects the trapezoid waveform Adp 2  included in the driving signal COMA in the period T 2 , does not select the trapezoid waveform Bdp 1  included in the driving signal COMB in the period T 3 , and does not select the trapezoid waveform Bdp 2  included in the driving signal COMB in the period T 4 . As a result, the driving signal VOUT corresponding to “the large dot” illustrated in  FIG. 4  is generated. 
     When the print data [SIH, SIL] is [1, 0], the decoder  226  sets the selection signal S 1  to have an H level and an L level in the periods T 1  and T 2 , and sets the selection signal S 2  to have an L level and an H level in the periods T 3  and T 4 . In this case, the selection circuit  230  selects the trapezoid waveform Adp 1  included in the driving signal COMA in the period T 1 , does not select the trapezoid waveform Adp 2  included in the driving signal COMA in the period T 2 , does not select the trapezoid waveform Bdp 1  included in the driving signal COMB in the period T 3 , and selects the trapezoid waveform Bdp 2  included in the driving signal COMB in the period T 4 . As a result, the driving signal VOUT corresponding to “the medium dot” illustrated in  FIG. 4  is generated. 
     When the print data [SIH, SIL] is [0, 1], the decoder  226  sets the selection signal S 1  to have an L level and an L level in the periods T 1  and T 2 , and sets the selection signal S 2  to have an L level and an H level in the periods T 3  and T 4 . In this case, the selection circuit  230  does not select the trapezoid waveform Adp 1  included in the driving signal COMA in the period T 1 , does not select the trapezoid waveform Adp 2  included in the driving signal COMA in the period T 2 , does not select the trapezoid waveform Bdp 1  included in the driving signal COMB in the period T 3 , and selects the trapezoid waveform Bdp 2  included in the driving signal COMB in the period T 4 . As a result, the driving signal VOUT corresponding to “the small dot” illustrated in  FIG. 4  is generated. 
     When the print data [SIH, SIL] is [0, 0], the decoder  226  sets the selection signal S 1  to have an L level and an L level in the periods T 1  and T 2 , and sets the selection signal S 2  to have an H level and an L level in the periods T 3  and T 4 . In this case, the selection circuit  230  does not select the trapezoid waveform Adp 1  included in the driving signal COMA in the period T 1 , does not select the trapezoid waveform Adp 2  included in the driving signal COMA in the period T 2 , selects the trapezoid waveform Bdp 1  included in the driving signal COMB in the period T 3 , and does not select the trapezoid waveform Bdp 2  included in the driving signal COMB in the period T 4 . As a result, the driving signal VOUT corresponding to “non-recording” illustrated in  FIG. 4  is generated. 
     As described above, the driving signal selection circuits  200 - 1  to  200 - n  control supplies of the corresponding driving signals COMA 1  to COMAn and COMB 1  to COMBn to the piezoelectric element based on the corresponding print data signals SI 1  to SIn, the latch signal LAT, and the change signals CHa and CHb, respectively. 
     1.5. Coupling Between Liquid Discharge Head and Liquid Discharge Head Control Circuit 
     Next, details of an electrical coupling between the control mechanism  10  and the liquid discharge head  21  will be described. The following descriptions will be made on the assumption that the liquid discharge head  21  includes twelve driving signal selection circuits  200 - 1  to  200 - 12 . That is, twelve print data signals SI 1  to S 112 , twelve driving signals COMA 1  to COMA 12  and COMB 1  to COMB 12 , and twelve voltages VBS 1  to VBS 12 , which respectively correspond to the twelve driving signal selection circuits  200 - 1  to  200 - 12 , are input to the liquid discharge head  21 . The control mechanism  10  includes twelve driving signal output circuits  50 - 1  to  50 - 12  which respectively correspond to the twelve driving signal selection circuits  200 - 1  to  200 - 12 . 
       FIG. 9  is a schematic diagram illustrating an internal configuration of the liquid discharge apparatus  1  when viewed from the Y-direction. As illustrated in  FIG. 9 , the liquid discharge apparatus  1  includes a main substrate  11 , the liquid discharge head  21 , and a plurality of cables  19  for electrically coupling the main substrate  11  and the liquid discharge head  21  to each other. 
     Various circuits including the conversion circuit  70 , the driving signal output circuits  50 - 1  to  50 - 12 , the first power source voltage output circuit  51 , the second power source voltage output circuit  52 , and the control circuit  100  provided in the control mechanism  10  illustrated in  FIGS. 1 and 2  are mounted on the main substrate  11 . A plurality of connectors  12  to which one ends of the plurality of cables  19  are respectively attached are mounted on the main substrate  11 .  FIG. 9  illustrates one circuit substrate as the main substrate  11 . However, the main substrate  11  may be configured by two circuit substrates or more. 
     The liquid discharge head  21  includes a head  310 , a head substrate  320 , and a plurality of connectors  350 . The other ends of the plurality of cables  19  are attached to the plurality of connectors  350 , respectively. Thus, various signals generated by the control mechanism  10  provided on the main substrate  11  are input to the liquid discharge head  21  through the plurality of cables  19 . Details of the configuration of the liquid discharge head  21  and details of signals propagated in the plurality of cables  19  will be described later. 
     The liquid discharge apparatus  1  configured in a manner as described above controls the operation of the liquid discharge head  21  based on various signals including the driving signals COMA 1  to COMA 12  and COMB 1  to COMB 12 , the voltages VBS 1  to VBS 12 , the differential clock signal dSCK, the differential print data signals dSI 1  to dSI 12 , the base latch signal oLAT, and the base change signals oCHa and oCHb, which are output from the control mechanism  10  mounted on the main substrate  11 . That is, in the liquid discharge apparatus  1  illustrated in  FIG. 9 , a configuration including the control mechanism  10  that outputs various signals for controlling the operation of the liquid discharge head  21  and the plurality of cables  19  for propagating the various signals for controlling the operation of the liquid discharge head  21  is an example of the liquid discharge head control circuit  15  that controls the operation of the liquid discharge head  21  that discharges the ink from nozzles  651 . 
       FIG. 10  is a diagram illustrating a configuration of the cable  19 . The cable  19  has a substantially rectangular shape having short sides  191  and  192  facing each other and long sides  193  and  194  facing each other. For example, the cable  19  is a flexible flat cable (FFC). The cable  19  includes a plurality of terminals  195  arranged in parallel along the short side  191 , a plurality of terminals  196  arranged in parallel along the short side  192 , and a plurality of wirings  197  that electrically couple the plurality of terminals  195  and the plurality of terminals  196  to each other. 
     Specifically, p pieces of terminals  195  are arranged in parallel from the long side  193  toward the long side  194 , on the short side  191  side of the cable  19  in order of the terminals  195 - 1  to  195 - p . p pieces of terminals  196  are arranged in parallel from the long side  193  toward the long side  194 , on the short side  192  side of the cable  19  in order of the terminals  196 - 1  to  196 - p . In the cable  19 , p pieces of wirings  197  that electrically and respectively couple the terminals  195  and the terminals  196  to each other are arranged in parallel from the long side  193  toward the long side  194  in order of the wirings  197 - 1  to  197 - p . The wiring  197 - 1  electrically couples the terminal  195 - 1  and the terminal  196 - 1  to each other. Similarly, the wiring  197 - j  (j is any of 1 to p) electrically couples the terminal  195 - j  and the terminal  196 - j  to each other. The cable  19  configured as described above is used for propagating a signal input from the terminal  195 - j  in the wiring  197 - j  and outputting the signal from the terminal  196 - j . Here, the plurality of wirings  197  in the cable  19  are coated with an insulator  198 . Thus, the plurality of wirings  197  are insulated from each other. The configuration of the cable  19  illustrated in  FIG. 10  is an example and is not limited thereto. For example, the plurality of terminals  195  and the plurality of terminals  196  may be provided on different surfaces of the cable  19 . 
     Next, a configuration of the liquid discharge head  21  to which a signal propagated in each of the plurality of cables  19  is input will be described.  FIG. 11  is a perspective view illustrating the configuration of the liquid discharge head  21 . As illustrated in  FIG. 11 , the liquid discharge head  21  includes the head  310  and the head substrate  320 . 
     The head substrate  320  has a surface  321  and a surface  322  different from the surface  321 . The plurality of connectors  350  are provided on the surface  322  of the head substrate  320 . The head  310  is provided on the surface  321  side of the head substrate  320 . An ink discharge surface  311  on which the plurality of discharge sections  600  are formed is located on a lower surface of the head  310  in the Z-direction. 
       FIG. 12  is a plan view illustrating a configuration of the ink discharge surface  311 . As illustrated in  FIG. 12 , twelve nozzle plates  632  are provided on the ink discharge surface  311 . The nozzle plate  632  has nozzles  651  provided in the plurality of discharge sections  600 . Nozzle lines L 1   a  to L 1   f  and L 2   a  to L 2   f  are formed in each of the nozzle plates  632 . In each of the nozzle lines, the nozzles  651  are arranged side by side in the Y-direction. 
     The nozzle lines L 1   a  to L 1   f  are provided to be arranged from the right to the left in  FIG. 12  in the X-direction in order of the nozzle lines L 1   a , L 1   b , L 1   c , L 1   d , L 1   e , and L 1   f . The nozzle lines L 2   a  to L 2   f  are provided to be arranged from the left to the right in  FIG. 12  in the X-direction in order of the nozzle lines L 2   a , L 2   b , L 2   c , L 2   d , L 2   e , and L 2   f . Further, the nozzle lines L 1   a  to L 1   f  and the nozzle lines L 2   a  to L 2   f  provided to be arranged in the X-direction are provided such that two lines are arranged side by side in the Y-direction. That is, the nozzle lines L 1   a  to L 1   f  and the nozzle lines L 2   a  to L 2   f  in which the plurality of nozzles  651  are formed in the Y-direction are formed in the ink discharge surface  311  in two lines in the X-direction. In  FIG. 12 , the nozzles  651  are provided to be arranged in one line in the Y-direction in each of the nozzle lines L 1   a  to L 1   f  and L 2   a  to L 2   f . However, the nozzles  651  may be provided to be arranged in two lines or more in the Y-direction. 
     The nozzle lines L 1   a  to L 1   f  and L 2   a  to L 2   f  correspond to the driving signal selection circuits  200 , respectively. Specifically, the driving signal selection circuit  200 - 1  corresponds to the nozzle line L 1   a . The driving signal VOUT 1  output by the driving signal selection circuit  200 - 1  is supplied to the one end of the piezoelectric element  60  in a plurality of discharge sections  600  provided in the nozzle line L 1   a . The voltage VBS 1  is supplied to the other end of this piezoelectric element  60 . Similarly, nozzle lines L 1   b  to L 1   f  correspond to the driving signal selection circuit  200 - 2  to  200 - 6 , respectively. The driving signals VOUT 2  to VOUT 6  and the voltages VBS 2  to VBS 6  are supplied to the driving signal selection circuit  200 - 2  to  200 - 6 , respectively. The nozzle lines L 2   a  to L 2   f  correspond to the driving signal selection circuit  200 - 7  to  200 - 12 , respectively. The driving signals VOUT 7  to VOUT 12  and the voltages VBS 7  to VBS 12  are supplied to the driving signal selection circuit  200 - 7  to  200 - 12 , respectively. 
     Next, the configuration of the discharge section  600  in the head  310  will be described with reference to  FIG. 13 .  FIG. 13  is a diagram illustrating an overall configuration of one of the plurality of discharge sections  600  in the head  310 . As illustrated in  FIG. 13 , the head  310  includes the discharge section  600  and a reservoir  641 . 
     The reservoir  641  is provided to correspond to each of the nozzle lines L 1   a  to L 1   f  and L 2   a  to L 2   f . The ink is supplied from an ink supply port  661  into the reservoir  641 . 
     The discharge section  600  includes the piezoelectric element  60 , a vibration plate  621 , a cavity  631 , and the nozzle  651 . The vibration plate  621  deforms by driving of the piezoelectric element  60  provided on an upper surface in  FIG. 13 . The vibration plate  621  functions as a diaphragm of increasing and reducing the internal volume of the cavity  631 . The cavity  631  is filled with the ink. The cavity  631  functions as a pressure chamber having an internal volume which changes by the deformation of the vibration plate  621 . The nozzle  651  is an opening portion which is formed in the nozzle plate  632  and communicates with the cavity  631 . The ink stored in the cavity  631  is discharged from the nozzle  651  by the change of the internal volume of the cavity  631 . 
     The piezoelectric element  60  has a structure in which a piezoelectric substance  601  is interposed between a pair of electrodes  611  and  612 . In the piezoelectric element  60  having such a structure, the central portions of the electrodes  611  and  612  and the vibration plate  621  bend with respect to both end portions thereof in an up-and-down direction in  FIG. 13 , in accordance with a voltage supplied to the electrodes  611  and  612 . Specifically, the driving signal VOUT is supplied to the electrode  611  as one end, and the voltage VBS is supplied to the electrode  612  as the other end. If the voltage of the driving signal VOUT is high, the central portion of the piezoelectric element  60  bends upward. If the voltage of the driving signal VOUT is low, the central portion of the piezoelectric element  60  bends downward. That is, if the piezoelectric element  60  bends upward, the internal volume of the cavity  631  increases. Thus, the ink is drawn from the reservoir  641 . If the piezoelectric element  60  bends downward, the internal volume of the cavity  631  is reduced. Accordingly, the ink of the amount depending on the reduced degree of the internal volume of the cavity  631  is discharged from the nozzle  651 . As described above, the piezoelectric element  60  drives by the driving signal VOUT based on the driving signals COMA and COMB. Thus, the piezoelectric element  60  drives by the driving signal VOUT based on the driving signals COMA 1  to COMAn and COMB 1  to COMBn, and thereby the ink is discharged from the nozzle  651 . The piezoelectric element  60  is not limited to the structure illustrated in  FIG. 13 . Any type may be provided so long as the piezoelectric element is capable of discharging the ink with the displacement of the piezoelectric element  60 . The piezoelectric element  60  is not limited to flexural vibration, and may be configured to use longitudinal vibration. 
     Next, a configuration of the head substrate  320  will be described with reference to  FIG. 14 .  FIG. 14  is a plan view when the head substrate  320  is viewed from the surface  321 . The head substrate  320  has a substantially rectangular shape formed by a side  323 , a side  324  (facing the side  323  in the X-direction), a side  325 , and a side  326  (facing the side  325  in the Y-direction). The shape of the head substrate  320  is not limited to a rectangle. For example, the shape of the head substrate  320  may be a polygon such as a hexagon or an octagon, or may have a shape in which a notch or an arc is formed. That is, the head substrate  320  has the side  323 , the side  324  different from the side  323 , the side  325  intersecting with the side  323  and the side  324 , and the side  326  which intersects with the side  323  and the side  324  and is different from the side  325 . Here, the sides  325  and  326  intersecting with the sides  323  and  324  includes a case where a virtual extension line of the side  325  intersects with a virtual extension line of the side  323  and a virtual extension line of the side  324 , and a virtual extension line of the side  326  intersects with a virtual extension line of the side  323  and a virtual extension line of the side  324 . 
     FPC insertion holes  331   a  to  331   f  and  341   a  to  341   f , electrode groups  332   a  to  332   f  and  342   a  to  342   f , and the plurality of connectors  350  are provided in the head substrate  320 . 
     Each of the electrode groups  332   a  to  332   f  and  342   a  to  342   f  includes a plurality of electrodes arranged in parallel in the Y-direction. The electrode groups  332   a  to  332   f  are provided to be arranged from the side  324  toward the side  323  along the side  326  in order of the electrode groups  332   a ,  332   b ,  332   c ,  332   d ,  332   e , and  332   f . The electrode groups  342   a  to  342   f  are provided to be arranged from the side  323  toward the side  324  along the side  325  in order of the electrode groups  342   a ,  342   b ,  342   c ,  342   d ,  342   e , and  342   f . A flexible printed circuit (FPC) (not illustrated) is electrically coupled to each of the electrode groups  332   a  to  332   f  and  342   a  to  342   f  provided in a manner as described above. 
     The FPC coupled to the electrode group  332   a  propagates various signals supplied to the electrode group  332   a  to the driving signal selection circuit  200 - 1 . That is, various control signals for controlling an operation of the nozzle line L 1   a  are supplied to the electrode group  332   a . Similarly, the FPC coupled to the electrode groups  332   b  to  332   f  propagates various signals supplied to the electrode groups  332   b  to  332   f  to the driving signal selection circuits  200 - 2  to  200 - 6 , respectively. That is, various control signals for controlling operations of the nozzle lines L 1   b  to L 1   f  are supplied to the electrode groups  332   b  to  332   f , respectively. Similarly, the FPC coupled to the electrode groups  342   a  to  342   f  propagates various signals supplied to the electrode groups  342   a  to  342   f  to the driving signal selection circuits  200 - 7  to  200 - 12 , respectively. That is, various control signals for controlling operations of the nozzle lines L 2   a  to L 2   f  are supplied to the electrode groups  342   a  to  342   f , respectively. 
     The FPC insertion holes  331   a  to  331   f  and  341   a  to  341   f  are through-holes penetrating the surface  321  and the surface  322  of the head substrate  320 . FPCs which are electrically coupled to the electrode groups  332   a  to  332   f  and  342   a  to  342   f  is inserted into the FPC insertion holes  331   a  to  331   f  and  341   a  to  341   f , respectively. 
     Specifically, the FPC insertion hole  331   a  is provided between the electrode group  332   a  and the electrode group  332   b . The FPC insertion hole  331   b  is provided between the electrode group  332   b  and the electrode group  332   c . The FPC insertion hole  331   c  is provided between the electrode group  332   c  and the electrode group  332   d . The FPC insertion hole  331   d  is provided between the electrode group  332   d  and the electrode group  332   e . The FPC insertion hole  331   e  is provided between the electrode group  332   e  and the electrode group  332   f . The FPC insertion hole  331   f  is provided on the side  323  side of the electrode group  332   f . The FPCs which are electrically coupled to the electrode groups  332   a  to  332   f  are inserted into the FPC insertion holes  331   a  to  33  if, respectively. 
     The FPC insertion hole  341   a  is provided between the electrode group  342   a  and the electrode group  342   b . The FPC insertion hole  341   b  is provided between the electrode group  342   b  and the electrode group  342   c . The FPC insertion hole  341   c  is provided between the electrode group  342   c  and the electrode group  342   d . The FPC insertion hole  341   d  is provided between the electrode group  342   d  and the electrode group  342   e . The FPC insertion hole  341   e  is provided between the electrode group  342   e  and the electrode group  342   f . The FPC insertion hole  341   f  is provided on the side  324  side of the electrode group  342   f . The FPCs which are electrically coupled to the electrode groups  342   a  to  342   f  are inserted into the FPC insertion holes  341   a  to  341   f , respectively. 
     The connectors  350   a  to  350   d  among the plurality of connectors  350  are provided on the side  323  side of the electrode groups  332   a  to  332   f  and  342   a  to  342   f  and the FPC insertion holes  331   a  to  331   f  and  341   a  to  341   f , respectively. The connectors  350   e  to  350   h  among the plurality of connectors  350  are provided on the side  324  side of the electrode groups  332   a  to  332   f  and  342   a  to  342   f  and the FPC insertion holes  331   a  to  331   f  and  341   a  to  341   f.    
     A configuration of the connector  350  will be described with reference to  FIG. 15 .  FIG. 15  is a diagram illustrating the configuration of the connector  350 . As illustrated in  FIG. 15 , the connector  350  includes a housing  351 , a cable attachment portion  352  formed in the housing  351 , and p pieces of terminals  353  arranged in parallel. Here, the p pieces of terminals  353  arranged in parallel in the connector  350  are referred to as terminals  353 - 1 ,  353 - 2 , . . . , and  353 - p  in order from the left toward the right in  FIG. 15 . 
     The cable  19  is attached to the plurality of connectors  350  configured in a manner as described above. Specifically, the cable  19  is attached to the cable attachment portion  352  of the connector  350 . In this case, the terminals  196 - 1  to  196 - p  of the cable  19  illustrated in  FIG. 11  are electrically coupled to the terminal  353 - 1  to  353 - p  of the connector  350 , respectively. Thus, various signals propagated in the wirings  197 - 1  to  197 - p  of the cable  19  are input to the liquid discharge head  21  through the connector  350 . 
     Here, a specific example of electrical coupling between the cable  19  and the connector  350  will be described with reference to  FIG. 16 .  FIG. 16  is a diagram illustrating a specific example when the cable  19  is attached to the connector  350 . As illustrated in  FIG. 16 , the terminal  353  of the connector  350  has a substrate attachment portion  354 , a housing insertion portion  355 , and a cable holding portion  356 . The substrate attachment portion  354  is located at a lower portion of the connector  350  and is provided between the housing  351  and the head substrate  320 . The substrate attachment portion  354  is electrically coupled to an electrode (not illustrated) provided on the head substrate  320 , by a solder, for example. The housing insertion portion  355  is inserted into the housing  351 . The housing insertion portion  355  electrically couples the substrate attachment portion  354  to the cable holding portion  356 . The cable holding portion  356  has a curved shape that protrudes toward the inside of the cable attachment portion  352 . When the cable  19  is attached to the cable attachment portion  352 , the cable holding portion  356  and the terminal  196  electrically come into contact with each other via a contact portion  180 . Thus, the cable  19  is electrically coupled to the connector  350  and the head substrate  320 . In this case, since the cable  19  is attached, stress is applied to the curved shape formed at the cable holding portion  356 . With the stress, the cable  19  is held in the cable attachment portion  352 . 
     As described above, the cable  19  and the connector  350  are electrically coupled to each other by the terminal  196  and the terminal  353  coming into contact with each other through the contact portion  180 .  FIG. 10  illustrates contact portions  180 - 1  to  180 - p  at which the terminals  196 - 1  to  196 - p  are electrically in contact with the terminal  353  of the connector  350 , respectively. Thus, the terminal  195 - k  in the cable  19  is electrically coupled to the connector  12 , and the terminal  196 - k  is electrically coupled to the connector  350  through the contact portion  180 - k.    
     Returning to  FIG. 14 , details of the arrangement of the connectors  350   a  to  350   h  provided in the head substrate  320  will be described. In the following descriptions, the housing  351  in the connector  350   a  is referred to as a housing  351   a , the cable attachment portion  352  in the connector  350   a  is referred to as a cable attachment portion  352   a , and the p pieces of terminals  353  in the connector  350   a  is referred to as p pieces of terminals  353   a . The p pieces of the terminals  353   a  are referred to as terminals  353   a - 1  to  353   a - p . Similarly, the housing  351  in the connectors  350   b  to  350   h  is referred to as housings  351   b  to  351   h . The cable attachment portion  352  in the connectors  350   b  to  350   h  is referred to as cable attachment portions  352   b  to  352   h . The p pieces of terminal  353  in the connectors  350   b  to  350   h  is referred to as p pieces of terminals  353   b  to  353   h . The p pieces of terminals  353   b  are referred as terminals  353   b - 1  to  353   b - p . The p pieces of terminals  353   c  are referred as terminals  353   c - 1  to  353   c - p . The p pieces of terminals  353   d  are referred as terminals  353   d - 1  to  353   d - p . The p pieces of terminals  353   e  are referred as terminals  353   e - 1  to  353   e - p . The p pieces of terminals  353   f  are referred as terminals  353   f - 1  to  353   f - p . The p pieces of terminals  353   g  are referred as terminals  353   g - 1  to  353   g - p . The p pieces of terminals  353   h  are referred as terminals  353   h - 1  to  353   h - p.    
     In the connector  350   a , the p pieces of terminals  353   a  are provided on the side  324  side of the electrode groups  332   a  to  332   f  and  342   a  to  342   f  and the FPC insertion holes  331   a  to  331   f  and  341   a  to  341   f , so as to be arranged from the side  325  toward the side  326  along the side  324  in order of the terminals  353   a - 1 ,  353   a - 2 , . . . , and  353   a - p.    
     In the connector  350   b , the p pieces of terminals  353   b  are provided on the side  324  side of the electrode groups  332   a  to  332   f  and  342   a  to  342   f  and the FPC insertion holes  331   a  to  331   f  and  341   a  to  341   f  and on the side  323  side of the connector  350   a , so as to be arranged from the side  326  toward the side  325  along the side  324  in order of the terminals  353   b - 1 ,  353   b - 2 , . . . , and  353   b - p.    
     In the connector  350   c , the p pieces of terminals  353   c  are provided on the side  324  side of the electrode groups  332   a  to  332   f  and  342   a  to  342   f  and the FPC insertion holes  331   a  to  331   f  and  341   a  to  341   f  and on the side  325  side of the connector  350   a , so as to be arranged from the side  325  toward the side  326  along the side  324  in order of the terminals  353   c - 1 ,  353   c - 2 , . . . , and  353   c - p.    
     In the connector  350   d , the p pieces of terminals  353   d  are provided on the side  324  side of the electrode groups  332   a  to  332   f  and  342   a  to  342   f  and the FPC insertion holes  331   a  to  331   f  and  341   a  to  341   f  and on the side  323  side of the connector  350   c , so as to be arranged from the side  326  toward the side  325  along the side  324  in order of the terminals  353   d - 1 ,  353   d - 2 , . . . , and  353   d - p.    
     In the connector  350   e , the p pieces of terminals  353   e  are provided on the side  323  side of the electrode groups  332   a  to  332   f  and  342   a  to  342   f  and the FPC insertion holes  331   a  to  331   f  and  341   a  to  341   f , so as to be arranged from the side  326  toward the side  325  along the side  323  in order of the terminals  353   e - 1 ,  353   e - 2 , . . . , and  353   e - p.    
     In the connector  350   f , the p pieces of terminals  353   f  are provided on the side  323  side of the electrode groups  332   a  to  332   f  and  342   a  to  342   f  and the FPC insertion holes  331   a  to  331   f  and  341   a  to  341   f  and on the side  324  side of the connector  350   e , so as to be arranged from the side  325  toward the side  326  along the side  323  in order of the terminals  353   f - 1 ,  353   f - 2 , . . . , and  353   f - p.    
     In the connector  350   g , the p pieces of terminals  353   g  are provided on the side  323  side of the electrode groups  332   a  to  332   f  and  342   a  to  342   f  and the FPC insertion holes  331   a  to  331   f  and  341   a  to  341   f  and on the side  325  side of the connector  350   a , so as to be arranged from the side  326  toward the side  325  along the side  323  in order of the terminals  353   g - 1 ,  353   g - 2 , . . . , and  353   g - p.    
     In the connector  350   h , the p pieces of terminals  353   h  are provided on the side  323  side of the electrode groups  332   a  to  332   f  and  342   a  to  342   f  and the FPC insertion holes  331   a  to  331   f  and  341   a  to  341   f  and on the side  324  side of the connector  350   g , so as to be arranged from the side  325  toward the side  326  along the side  323  in order of the terminals  353   h - 1 ,  353   h - 2 , . . . , and  353   h - p.    
     Various signals for controlling the liquid discharge head  21  are supplied to the head substrate  320  configured in a manner as described above, through the plurality of cables  19  which are electrically and respectively coupled to the connectors  350   a  to  350   h . The various signals supplied to the liquid discharge head  21  are propagated in a wiring pattern (not illustrated) provided in the head substrate  320 , and then are input to the electrode groups  332   a  to  332   f  and  342   a  to  342   f . The various signals are supplied to the driving signal selection circuits  200 - 1  to  200 - 12  through the FPCs coupled to the electrode groups  332   a  to  332   f  and  342   a  to  342   f , respectively. Thus, the piezoelectric element  60  in each of the nozzle lines L 1   a  to L 1   f  and L 2   a  to L 2   f  drives at a desired timing, and thus an ink having an amount depending on the driving of the piezoelectric element  60  is discharged from the nozzle  651 . 
     Here, the integrated circuit constituting the restoration circuit  130  in the liquid discharge head  21  illustrated in  FIG. 2  may be provided on the inside of the surface  322 , the surface  321 , and the head  310  of the head substrate  320 , or may be mounted on an FPC in a manner of chip-on-film (COF). The integrated circuit constituting each of the driving signal selection circuits  200 - 1  to  200 - 6  may be provided in the head  310  or may be mounted on an FPC in a manner of COF. 
     1.6. Signal Propagated Between Liquid Discharge Head and Liquid Discharge Head Control Circuit 
     Here, details of a signal propagated between the control mechanism  10  and the liquid discharge head  21  will be described. In the following descriptions, the cable  19  coupled to the connector  350   a  is referred to as a cable  19   a . A terminal  196   a - j  (j is any of 1 to p) of the cable  19   a  is electrically coupled to the terminal  353   a - j  of the connector  350   a  through a contact portion  180   a - j . Similarly, the cable  19  coupled to the connectors  350   b  to  350   h  is referred to as cables  19   b  to  19   h . A terminal  196   b - j  of the cable  19   b  is electrically coupled to the terminal  353   b - j  of the connector  350   b  through a contact portion  180   b - j . A terminal  196   c - j  of the cable  19   c  is electrically coupled to the terminal  353   c - j  of the connector  350   c  through a contact portion  180   c - j . A terminal  196   d - j  of the cable  19   d  is electrically coupled to the terminal  353   d - j  of the connector  350   d  through a contact portion  180   d - j . A terminal  196   e - j  of the cable  19   e  is electrically coupled to the terminal  353   e - j  of the connector  350   e  through a contact portion  180   e - j . A terminal  196   f - j  of the cable  19   f  is electrically coupled to the terminal  353   f - j  of the connector  350   f  through a contact portion  180   f - j . A terminal  196   g - j  of the cable  19   g  is electrically coupled to the terminal  353   g - j  of the connector  350   g  through a contact portion  180   g - j . A terminal  196   h - j  of the cable  19   h  is electrically coupled to the terminal  353   h - j  of the connector  350   h  through a contact portion  180   h - j.    
       FIG. 17  is a diagram illustrating details of a signal which is propagated in the cable  19   a  and is input to the liquid discharge head  21  through the connector  350   a . As illustrated in  FIG. 17 , the cable  19   a  is used for propagating a plurality of control signals including the ground signal GND 1  and the voltages VHV and VDD to be supplied to the plurality of driving signal selection circuits  200 . Thus, the plurality of control signals propagated in the cable  19   a  are supplied to the liquid discharge head  21  through the connector  350   a.    
     Specifically, the ground signal GND 1  is propagated in each of wirings  197   a - 2  and  197   a - 4  to  197   a - 19 . The ground signal GND 1  is input to the driving signal selection circuits  200 - 1  to  200 - 12  through the contact portions  180   a - 3  and  180   a - 4  to  180   a - 19  and the terminals  353   a - 3  and  353   a - 4  to  353   a - 19  in the liquid discharge head  21 , respectively. The voltage VHV is propagated in a wiring  197   a - 1 . The voltage VHV is input to the driving signal selection circuits  200 - 1  to  200 - 12  through the contact portion  180   a - 1  and the terminal  353   a - 1  in the liquid discharge head  21 . The voltage VDD is propagated in each of wirings  197   a - 20  to  197   a - 23 . The voltage VDD is input to the restoration circuit  130  and the driving signal selection circuits  200 - 1  to  200 - 12  through the contact portions  180   a - 20  to  180   a - 23  and the terminals  353   a - 20  to  353   a - 23  in the liquid discharge head  21 , respectively. Here, the ground signal GND 1  is an example of a first reference voltage signal. 
     The cable  19   a  is used for propagating a plurality of control signals such as a signal XHOT and a signal TH. The signal XHOT indicates temperature abnormality of the liquid discharge head  21 . The signal TH indicates temperature information of the liquid discharge head  21 . The plurality of control signals such as the signals XHOT and TH are input to the liquid discharge head  21  through the connector  350   a.    
       FIG. 18  is a diagram illustrating details of a signal which is propagated in the cable  19   b  and is input to the liquid discharge head  21  through the connector  350   b . As illustrated in  FIG. 18 , the cable  19   b  is used for propagating a plurality of control signals including the differential signal including the differential clock signal dSCK and the differential print data signals dSI 1  to dSI 6 , and the single-ended signal including the base latch signal oLAT, the base change signals oCHa and oCHb, and the ground signals GND 1  and GND 2 . The plurality of control signals propagated in the cable  19   b  are supplied to the liquid discharge head  21  through the connector  350   b.    
     The pair of differential clock signals dSCK are propagated in wirings  197   b - 4  and  197   b - 5 . Specifically, one signal dSCK+ in the pair of differential clock signal dSCK is propagated in the wiring  197   b - 4 . The signal dSCK+ is input to the restoration circuit  130  through a contact portion  180   b - 4  and the terminal  353   b - 4  in the liquid discharge head  21 . That is, the terminal  353   b - 4  is electrically coupled to the restoration circuit  130 . The wiring  197   b - 4  is electrically coupled to the terminal  353   b - 4  through the contact portion  180   b - 4 , and is used for propagating the one signal dSCK+ in the pair of differential clock signal dSCK. Thus, the one signal dSCK+ in the pair of differential clock signal dSCK is input to the terminal  353   b - 4 . 
     The other signal dSCK− in the pair of differential clock signal dSCK is propagated in the wiring  197   b - 5 . The signal dSCK− is input to the restoration circuit  130  through a contact portion  180   b - 5  and the terminal  353   b - 5  in the liquid discharge head  21 . That is, the terminal  353   b - 5  is electrically coupled to the restoration circuit  130 . The wiring  197   b - 5  is electrically coupled to the terminal  353   b - 5  through the contact portion  180   b - 5 , and is used for propagating the other signal dSCK− in the pair of differential clock signals dSCK. Thus, the other signal dSCK− in the pair of differential clock signal dSCK is input to the terminal  353   b - 5 . Here, the terminal  353   b - 4  is an example of a fourth terminal. The wiring  197   b - 4  is an example of a fourth wiring. The terminal  353   b - 5  is an example of a fifth terminal. The wiring  197   b - 5  is an example of a fifth wiring. The contact portion  180   b - 4  at which the wiring  197   b - 4  and the terminal  353   b - 4  are electrically in contact with each other is an example of a fourth contact portion. The contact portion  180   b - 5  at which the wiring  197   b - 5  and the terminal  353   b - 5  are electrically in contact with each other is an example of a fifth contact portion. 
     A pair of differential print data signals dSI 1  are propagated in wirings  197   b - 7  and  197   b - 8 . Specifically, one signal dSI 1 + in the pair of differential print data signals dSI 1  is propagated in the wiring  197   b - 7 . The signal dSI 1 + is input to the restoration circuit  130  through a contact portion  180   b - 7  and the terminal  353   b - 7  in the liquid discharge head  21 . That is, the terminal  353   b - 7  is electrically coupled to the restoration circuit  130 . The wiring  197   b - 7  is electrically coupled to the terminal  353   b - 7  through the contact portion  180   b - 7 , and is used for propagating the one signal dSI 1 + in the pair of differential print data signals dSI 1 . Thus, the one signal dSI 1 + in the pair of differential print data signals dSI 1  is input to the terminal  353   b - 7 . 
     The other signal dSI 1 − in the pair of differential print data signals dSI 1  is propagated in the wiring  197   b - 8 . The signal dSI 1 − is input to the restoration circuit  130  through a contact portion  180   b - 8  and the terminal  353   b - 8  in the liquid discharge head  21 . That is, the terminal  353   b - 8  is electrically coupled to the restoration circuit  130 . The wiring  197   b - 8  is electrically coupled to the terminal  353   b - 8  through the contact portion  180   b - 8 , and is used for propagating the other signal dSI 1 − in the pair of differential print data signals dSI 1 . Thus, the other signal dSI 1 − in the pair of differential print data signals dSI 1  is input to the terminal  353   b - 8 . 
     The pair of differential print data signals dSI 2  to dSI 6  are propagated in wirings  197   b - 9  to  197   b - 18 , respectively. Specifically, one signals dSI 2 +, dSI 3 +, dSI 4 +, dSI 5 +, and dSI 6 + of the pair of differential print data signals dSI 2  to dSI 6  are propagated in the wirings  197   b - 9 ,  197   b - 11 ,  197   b - 13 ,  197   b - 15 , and  197   b - 17 , respectively. The signals dSI 2 +, dSI 3 +, dSI 4 +, dSI 5 +, and dSI 6 + are input to the restoration circuit  130  through contact portions  180   b - 9 ,  180   b - 11 ,  180   b - 13 ,  180   b - 15 , and  180   b - 17  and the terminals  353   b - 9 ,  353   b - 11 ,  353   b - 13 ,  353   b - 15 , and  353   b - 17  in the liquid discharge head  21 , respectively. The other signals signal dSI 2 −, dSI 3 , dSI 4 −, dSI 5 −, and dSI 6 − of the pair of differential print data signals dSI 2  to dSI 6  are propagated in the wirings  197   b - 10 ,  197   b - 12 ,  197   b - 14 ,  197   b - 16 , and  197   b - 18 , respectively. The signal dSI 2 −, dSI 3 , dSI 4 −, dSI 5 −, and dSI 6 − are input to the restoration circuit  130  through contact portions  180   b - 10 ,  180   b - 12 ,  180   b - 14 ,  180   b - 16 , and  180   b - 18  and the terminals  353   b - 10 ,  353   b - 12 ,  353   b - 14 ,  353   b - 16 , and  353   b - 18  in the liquid discharge head  21 . 
     The base latch signal oLAT is propagated in a wiring  197   b - 20 . The base latch signal oLAT is input to the restoration circuit  130  through the terminal  353   b - 20  in the liquid discharge head  21 . That is, the terminal  353   b - 20  is electrically coupled to the restoration circuit  130 . The wiring  197   b - 20  is electrically coupled to the terminal  353   b - 20  through a contact portion  180   b - 20  and is used for propagating the base latch signal oLAT. Thus, the base latch signal oLAT is input to the terminal  353   b - 20 . Here, the base latch signal oLAT is an example of a second control signal. The terminal  353   b - 20  is an example of a seventh terminal. The wiring  197   b - 20  is an example of a seventh wiring. The contact portion  180   b - 20  at which the wiring  197   b - 20  and the terminal  353   b - 20  are electrically in contact with each other is an example of a seventh contact portion. 
     The base change signal oCHa is propagated in a wiring  197   b - 22 . The base change signal oCHa is input to the restoration circuit  130  through a contact portion  180   b - 22  and the terminal  353   b - 22  in the liquid discharge head  21 . That is, the terminal  353   b - 22  is electrically coupled to the restoration circuit  130 . The wiring  197   b - 22  is electrically coupled to the terminal  353   b - 22  through a contact portion  180   b - 22  and is used for propagating the base change signal oCHa. Thus, the base change signal oCHa is input to the terminal  353   b - 22 . 
     The base change signal oCHb is propagated in a wiring  197   b - 23 . The base change signal oCHb is input to the restoration circuit  130  through a contact portion  180   b - 23  and the terminal  353   b - 23  in the liquid discharge head  21 . That is, the terminal  353   b - 23  is electrically coupled to the restoration circuit  130 . The wiring  197   b - 23  is electrically coupled to the terminal  353   b - 23  through a contact portion  180   b - 23  and is used for propagating the base change signal oCHb. Thus, the base change signal oCHb is input to the terminal  353   b - 23 . 
     The ground signal GND 1  is propagated in wirings  197   b - 19  and  197   b - 21 . The ground signal GND 1  is input to the driving signal selection circuits  200 - 1  to  200 - 12  through contact portions  180   b - 19  and  180   b - 21  and the terminals  353   b - 19  and  353   b - 21  in the liquid discharge head  21 . That is, the terminal  353   b - 19  is electrically coupled to the driving signal selection circuits  200 - 1  to  200 - 12 . The wiring  197   b - 19  is electrically coupled to the terminal  353   b - 19  through a contact portion  180   b - 19  and is used for propagating the ground signal GND 1 . Thus, the ground signal GND 1  is input to the terminal  353   b - 19 . The terminal  353   b - 21  is electrically coupled to the driving signal selection circuits  200 - 1  to  200 - 12 . The wiring  197   b - 21  is electrically coupled to the terminal  353   b - 21  through a contact portion  180   b - 21  and is used for propagating the ground signal GND 1 . Thus, the ground signal GND 1  is input to the terminal  353   b - 21 . Here, the terminal  353   b - 19  is an example of a first terminal. The wiring  197   b - 19  is an example of a first wiring. The contact portion  180   b - 19  at which the wiring  197   b - 19  and the terminal  353   b - 19  are electrically in contact with each other is an example of a first contact portion. The terminal  353   b - 21  is an example of a sixth terminal. The wiring  197   b - 21  is an example of a sixth wiring. The contact portion  180   b - 21  at which the wiring  197   b - 21  and the terminal  353   b - 21  are electrically in contact with each other is an example of a sixth contact portion. 
     Regarding the wirings  197   b - 19  and  197   b - 21  which are disposed in a manner as described above and in which the ground signal GND 1  is propagated, the wiring  197   b - 20  in which the base latch signal oLAT is propagated is located to be adjacent to the wiring  197   b - 19  and the wiring  197   b - 21  in the Y-direction in which the wiring  197   b - 4  and the wiring  197   b - 5  are arranged. That is, regarding the terminals  353   b - 19  and  353   b - 21  to which the ground signal GND 1  is input, the terminal  353   b - 20  to which the base latch signal oLAT is input is located to be adjacent to the terminal  353   b - 19  and the terminal  353   b - 21  in the Y-direction in which the terminal  353   b - 4  and the terminal  353   b - 5  are arranged. Thus, it is possible to shield the wiring in which the base latch signal oLAT is propagated, by the ground signal GND 1 , and to reduce a concern that external noise is superimposed on the base latch signal oLAT. 
     The ground signal GND 2  is propagated in wirings  197   b - 3  and  197   b - 6 . The ground signal GND 2  is input to the restoration circuit  130  through contact portions  180   b - 3  and  180   b - 6  and the terminals  353   b - 3  and  353   b - 6  in the liquid discharge head  21 . That is, the terminals  353   b - 3  and  353   b - 6  are electrically coupled to the restoration circuit  130 . The wiring  197   b - 3  is electrically coupled to the terminal  353   b - 3  through the contact portion  180   b - 3  and is used for propagating the ground signal GND 2  to be supplied to the restoration circuit  130 . The wiring  197   b - 6  is electrically coupled to the terminal  353   b - 6  through the contact portion  180   b - 6 , and is used for propagating the ground signal GND 2  to be supplied to the restoration circuit  130 . Thus, the ground signal GND 2  to be supplied to the restoration circuit  130  is input to the terminals  353   b - 3  and  353 - 6 . Here, the ground signal GND 2  is an example of a second reference voltage signal. The terminal  353   b - 3  is an example of a second terminal. The wiring  197   b - 3  is an example of a second wiring. The contact portion  180   b - 3  at which the wiring  197   b - 3  and the terminal  353   b - 3  are electrically in contact with each other is an example of a second contact portion. The terminal  353   b - 6  is an example of a third terminal. The wiring  197   b - 6  is an example of a third wiring. The contact portion  180   b - 6  at which the wiring  197   b - 6  and the terminal  353   b - 6  are electrically in contact with each other is an example of a third contact portion. 
     As described above, in the liquid discharge head control circuit  15 , the wiring  197   b - 4  in which the signal dSCK+ is propagated and the wiring  197   b - 5  in which the signal dSCK− is propagated are disposed to be arranged side by side in the Y-direction. In the Y-direction in which the wiring  197   b - 4  and the wiring  197   b - 5  are arranged, the wiring  197   b - 4  and the wiring  197   b - 3  are located to be adjacent to each other, the wiring  197   b - 5  and the wiring  197   b - 6  are located to be adjacent to each other, and the wiring  197   b - 4  and the wiring  197   b - 5  are located between the wiring  197   b - 3  and the wiring  197   b - 6 . That is, in the liquid discharge head control circuit  15 , the wirings  197   b - 3 ,  197   b - 4 ,  197   b - 5 , and  197   b - 6  are provided in the same cable  19   b . The wiring  197   b - 4  and the wiring  197   b - 3  are located to be adjacent to each other. The wiring  197   b - 5  and the wiring  197   b - 6  are located to be adjacent to each other. The wiring  197   b - 4  and the wiring  197   b - 5  are located between the wiring  197   b - 3  and the wiring  197   b - 6 . Here, the phrase of being located to be adjacent includes a case where the wiring and the wiring are located to be adjacent to each other through the insulator  198 , a space, or the like. In other words, the wirings  197   b - 3 ,  197   b - 4 ,  197   b - 5 , and  197   b - 6  are provided in the same cable  19   b  in order of the wirings  197   b - 3 ,  197   b - 4 ,  197   b - 5 , and  197   b - 6 . 
     In the liquid discharge head  21 , the terminal  353   b - 4  to which the signal dSCK+ is input and the terminal  353   b - 5  to which the signal dSCK− is input are disposed to be arranged side by side in the Y-direction. In the Y-direction in which the terminal  353   b - 4  and the terminal  353   b - 5  are arranged, the terminal  353   b - 4  and the terminal  353   b - 3  are located to be adjacent to each other, the terminal  353   b - 5  and the terminal  353   b - 6  are located to be adjacent to each other, and the terminal  353   b - 4  and the terminal  353   b - 5  are located between the terminal  353   b - 3  and the terminal  353   b - 6 . That is, in the liquid discharge head  21 , the terminals  353   b - 3 ,  353   b - 4 ,  353   b - 5 , and  353   b - 6  are provided in the same connector  350   b . The terminal  353   b - 4  and the terminal  353   b - 3  are located to be adjacent to each other. The terminal  353   b - 5  and the terminal  353   b - 6  are located to be adjacent to each other. The terminal  353   b - 4  and the terminal  353   b - 5  are located between the terminal  353   b - 3  and the terminal  353   b - 6 . Here, the phrase of being located to be adjacent includes a case where the terminal  353   b - 4  and the terminal  353   b - 3 , and the terminal  353   b - 5  and the terminal  353   b - 6  in the connector  350  are located to be adjacent to each other through, for example, an insulator such as the housing  351  or an internal space of the cable attachment portion  352 . In other words, the terminals  353   b - 3 ,  353   b - 4 ,  353   b - 5 , and  353   b - 6  are provided in the same connector  350   b  in order of the terminals  353   b - 3 ,  353   b - 4 ,  353   b - 5 , and  353   b - 6 . 
     In the liquid discharge apparatus  1 , the contact portion  180   b - 4  and the contact portion  180   b - 5  are disposed to be arranged side by side. In the Y-direction being a direction in which the contact portion  180   b - 4  and the contact portion  180   b - 5  are arranged, the contact portion  180   b - 4  and the contact portion  180   b - 3  are located to be adjacent to each other, the contact portion  180   b - 5  and the contact portion  180   b - 6  are located to be adjacent to each other, and the contact portion  180   b - 4  and the contact portion  180   b - 5  are located between the contact portion  180   b - 3  and the contact portion  180   b - 6 . That is, in the liquid discharge apparatus  1 , the contact portions  180   b - 3 ,  180   b - 4 ,  180   b - 5 , and  180   b - 6  are included in a plurality of contact portions  180   b  at which the cable  19   b  and the connector  350   b  are electrically in contact with each other. The contact portion  180   b - 4  and the contact portion  180   b - 3  are located to be adjacent to each other. The contact portion  180   b - 5  and the contact portion  180   b - 6  are located to be adjacent to each other. The contact portion  180   b - 4  and the contact portion  180   b - 5  are located between the contact portion  180   b - 3  and the contact portion  180   b - 6 . Here, the phrase of being located to be adjacent includes a case where, at the plurality of contact portions  180   b  at which the cable  19   b  and the connector  350   b  are electrically in contact with each other, the contact portion  180   b - 4  and the contact portion  180   b - 3 , and the contact portion  180   b - 5  and the contact portion  180   b - 6  are located to be adjacent to each other through a space and the like. In other words, the contact portions  180   b - 3 ,  180   b - 4 ,  180   b - 5 , and  180   b - 6  are provided in the plurality of contact portions  180   b  at which the cable  19   b  and the connector  350   b  are electrically in contact with each other, in order of the contact portions  180   b - 3 ,  180   b - 4 ,  180   b - 5 , and  180   b - 6 . 
     Thus, it is possible to shield the wiring in which the differential clock signal dSCK is propagated, by the ground signal GND 2 , and to reduce a concern that external noise is superimposed on the differential clock signal dSCK. Further, since the ground signal GND 2  to be supplied to the restoration circuit  130  is used as a ground for shielding the differential clock signal dSCK, it is possible to reduce a current path generated based on the differential clock signal dSCK. Accordingly, it is possible to reduce distortion of a waveform occurring in the differential clock signal dSCK. 
     The cable  19   b  is used for propagating a plurality of control signals such as a signal NVTS, a signal TSIG, and a signal NCHG. The signal NVTS is used for detecting a discharge state of an ink from the liquid discharge head  21 . The signal TSIG is used for defining a detection timing of the discharge state of the ink by the signal NVTS. The signal NCHG is used for forcibly driving the plurality of piezoelectric elements  60  in the liquid discharge head  21 . The plurality of control signals such as the signals NVTS, TSIG, and NCHG are input to the liquid discharge head  21  through the connector  350   b.    
       FIG. 19  is a diagram illustrating details of a signal which is propagated in the cable  19   c  and is input to the liquid discharge head  21  through the connector  350   c .  FIG. 20  is a diagram illustrating details of a signal which is propagated in the cable  19   d  and is input to the liquid discharge head  21  through the connector  350   d . As illustrated in  FIGS. 19 and 20 , the cable  19   c  and the cable  19   d  are used for propagating the driving signals COMA 7  to COMA 12  and COMB 7  to COMB 12  (being bases of the driving signals VOUT 7  to VOUT 12  to be supplied to one ends of the piezoelectric elements  60  included in the nozzle lines L 2   a  to L 2   f ) and the voltage VBS 7  to VBS 12  (to be supplied to the other ends of the piezoelectric elements  60 ). 
     Specifically, the driving signal COMA 7  being the base of the driving signal VOUT 7  to be supplied to one end of the piezoelectric element  60  included in the nozzle line L 2   a  is propagated in wirings  197   d - 22  and  197   d - 24 . The driving signal COMA 7  is input to the driving signal selection circuit  200 - 7  through contact portions  180   d - 22  and  180   d - 24 , and the terminals  353   d - 22  and  353   d - 24 . The driving signal COMB 7  being the base of the driving signal VOUT 7  is propagated in wirings  197   c - 2  and  197   c - 4 . The driving signal COMB 7  is input to the driving signal selection circuit  200 - 7  through contact portions  180   c - 2  and  180   c - 4  and the terminals  353   c - 2  and  353   c - 4 . The voltage VBS 7  is propagated in wirings  197   c - 1 ,  197   c - 3 ,  197   d - 21 , and  197   d - 23 . The voltage VBS 7  is supplied to the other end of the piezoelectric element  60  through contact portions  180   c - 1 ,  180   c - 3 ,  180   d - 21 , and  180   d - 23  and the terminals  353   c - 1 ,  353   c - 3 ,  353   d - 21 , and  353   d - 23 . 
     The driving signal COMA 8  being the base of the driving signal VOUT 8  to be supplied to one end of the piezoelectric element  60  included in the nozzle line L 2   b  is propagated in wirings  197   c - 6  and  197   c - 8 . The driving signal COMA 8  is input to the driving signal selection circuit  200 - 8  through contact portions  180   c - 6  and  180   c - 8  and the terminals  353   c - 6  and  353   c - 8 . The driving signal COMB 8  being the base of the driving signal VOUT 8  is propagated in wirings  197   d - 20  and  197   d - 18 . The driving signal COMB 8  is input to the driving signal selection circuit  200 - 8  through contact portions  180   d - 20  and  180   d - 18 , and the terminals  353   d - 20  and  353   d - 18 . The voltage VBS 8  is propagated in wirings  197   c - 5 ,  197   c - 7 ,  197   d - 17 , and  197   d - 19 . The voltage VBS 8  is supplied to the other end of the piezoelectric element  60  through contact portions  180   c - 5 ,  180   c - 7 ,  180   d - 17 , and  180   d - 19  and the terminals  353   c - 5 ,  353   c - 7 ,  353   d - 17 , and  353   d - 19 . 
     The driving signal COMA 9  being the base of the driving signal VOUT 9  to be supplied to one end of the piezoelectric element  60  included in the nozzle line L 2   c  is propagated in wirings  197   d - 14  and  197   d - 16 . The driving signal COMA 9  is input to the driving signal selection circuit  200 - 9  through contact portions  180   d - 14  and  180   d - 16 , and the terminals  353   d - 14  and  353   d - 16 . The driving signal COMB 9  being the base of the driving signal VOUT 9  is propagated in wirings  197   c - 10  and  197   c - 12 . The driving signal COMB 9  is input to the driving signal selection circuit  200 - 9  through contact portions  180   c - 10  and  180   c - 12  and the terminals  353   c - 10  and  353   c - 12 . The voltage VBS 9  is propagated in wirings  197   c - 9 ,  197   c - 11 ,  197   d - 13 , and  197   d - 15 . The voltage VBS 9  is supplied to the other end of the piezoelectric element  60  through contact portions  180   c - 9 ,  180   c - 11 ,  180   d - 13 , and  180   d - 15  and the terminals  353   c - 9 ,  353   c - 11 ,  353   d - 13 , and  353   d - 15 . 
     The driving signal COMA 10  being the base of the driving signal VOUT 10  to be supplied to one end of the piezoelectric element  60  included in the nozzle line L 2   d  is propagated in wirings  197   c - 14  and  197   c - 16 . The driving signal COMA 10  is input to the driving signal selection circuit  200 - 10  through contact portions  180   c - 14  and  180   c - 16 , and the terminals  353   c - 14  and  353   c - 16 . The driving signal COMB 10  being the base of the driving signal VOUT 10  is propagated in wirings  197   d - 10  and  197   d - 12 . The driving signal COMB 10  is input to the driving signal selection circuit  200 - 10  through contact portions  180   d - 10  and  180   d - 12  and the terminals  353   d - 10  and  353   d - 12 . The voltage VBS 10  is propagated in wirings  197   c - 13 ,  197   c - 15 ,  197   d - 9 , and  197   d - 11 . The voltage VBS 10  is supplied to the other end of the piezoelectric element  60  through contact portions  180   c - 13 ,  180   c - 15 ,  180   d - 9 , and  180   d - 11  and the terminals  353   c - 13 ,  353   c - 15 ,  353   d - 9 , and  353   d - 11 . 
     The driving signal COMA 11  being the base of the driving signal VOUT 11  to be supplied to one end of the piezoelectric element  60  included in the nozzle line L 2   e  is propagated in wirings  197   d - 6  and  197   d - 8 . The driving signal COMA 11  is input to the driving signal selection circuit  200 - 11  through contact portions  180   d - 6  and  180   d - 8 , and the terminals  353   d - 6  and  353   d - 8 . The driving signal COMB 11  being the base of the driving signal VOUT 11  is propagated in wirings  197   c - 18  and  197   c - 20 . The driving signal COMB 11  is input to the driving signal selection circuit  200 - 11  through contact portions  180   c - 18  and  180   c - 20  and the terminals  353   c - 18  and  353   c - 20 . The voltage VBS 11  is propagated in wirings  197   c - 17 ,  197   c - 19 ,  197   d - 5 , and  197   d - 7 . The voltage VBS 11  is supplied to the other end of the piezoelectric element  60  through contact portions  180   c - 17 ,  180   c - 19 ,  180   d - 5 , and  180   d - 7  and the terminals  353   c - 17 ,  353   c - 19 ,  353   d - 5 , and  353   d - 7 . 
     The driving signal COMA 12  being the base of the driving signal VOUT 12  to be supplied to one end of the piezoelectric element  60  included in the nozzle line L 2   f  is propagated in wirings  197   c - 22  and  197   c - 24 . The driving signal COMA 12  is input to the driving signal selection circuit  200 - 12  through contact portions  180   c - 22  and  180   c - 24 , and the terminals  353   c - 22  and  353   c - 24 . The driving signal COMB 12  being the base of the driving signal VOUT 12  is propagated in wirings  197   d - 2  and  197   d - 4 . The driving signal COMB 12  is input to the driving signal selection circuit  200 - 12  through contact portions  180   d - 2  and  180   d - 4  and the terminals  353   d - 2  and  353   d - 4 . The voltage VBS 12  is propagated in wirings  197   c - 22 ,  197   c - 24 ,  197   d - 2 , and  197   d - 4 . The voltage VBS 12  is supplied to the other end of the piezoelectric element  60  through contact portions  180   c - 22 ,  180   c - 24 ,  180   d - 2 , and  180   d - 4  and the terminals  353   c - 22 ,  353   c - 24 ,  353   d - 2 , and  353   d - 4 . 
       FIG. 21  is a diagram illustrating details of a signal which is propagated in the cable  19   e  and is input to the liquid discharge head  21  through the connector  350   e . As illustrated in  FIG. 21 , the cable  19   e  is used for propagating a plurality of control signals including the ground signal GND 1  and the voltage VHV to be supplied to the plurality of driving signal selection circuits  200 . The plurality of control signals propagated in the cable  19   e  are supplied to the liquid discharge head  21  through the connector  350   e.    
     Specifically, the ground signal GND 1  is propagated in each of wirings  197   e - 2  and  197   e - 4  to  197   e - 19 . The ground signal GND 1  is input to the driving signal selection circuits  200 - 1  to  200 - 12  through the contact portions  180   e - 2  and  180   e - 4  to  180   e - 19  and the terminals  353   e - 3  and  353   e - 4  to  353   e - 19  in the liquid discharge head  21 , respectively. The voltage VHV is propagated in a wiring  197   e - 1 . The voltage VHV is input to the driving signal selection circuits  200 - 1  to  200 - 12  through the contact portion  180   e - 1  and the terminal  353   e - 1  in the liquid discharge head  21 . The voltage VDD is propagated in wirings  197   e - 20  to  197   e - 23 . The voltage VDD is input to the restoration circuit  130  and the driving signal selection circuits  200 - 1  to  200 - 12  through the contact portions  180   e - 20  to  180   e - 23  and the terminals  353   e - 20  to  353   e - 23  in the liquid discharge head  21 , respectively. 
     The cable  19   e  is used for propagating a plurality of control signals such as a signal XHOT and a signal TH. The signal XHOT indicates temperature abnormality of the liquid discharge head  21 . The signal TH indicates temperature information of the liquid discharge head  21 . The plurality of control signals such as the signals XHOT and TH are input to the liquid discharge head  21  through the connector  350   a.    
       FIG. 22  is a diagram illustrating details of a signal which is propagated in the cable  19   f  and is input to the liquid discharge head  21  through the connector  350   f . As illustrated in  FIG. 22 , the cable  19   f  is used for propagating a plurality of control signals including the differential signal including the differential clock signal dSCK and the differential print data signals dSI 7  to dSI 12 , and the single-ended signal including the base latch signal oLAT, the base change signals oCHa and oCHb, and the ground signals GND 1  and GND 2 . The plurality of control signals propagated in the cable  19   f  are supplied to the liquid discharge head  21  through the connector  350   f.    
     The pair of differential clock signals dSCK are propagated in wirings  197   f - 4  and  197   f - 5 . Specifically, one signal dSCK+ in the pair of differential clock signals dSCK is propagated in the wiring  197   f - 4 . The signal dSCK+ is input to the restoration circuit  130  through a contact portion  180   f - 4  and the terminal  353   f - 4  in the liquid discharge head  21 . The other signal dSCK− in the pair of differential clock signals dSCK is propagated in the wiring  197   f - 5 . The signal dSCK− is input to the restoration circuit  130  through a contact portion  180   f - 5  and the terminal  353   f - 5  in the liquid discharge head  21 . 
     The pair of differential print data signals dSI 7  to dSI 12  are propagated in wirings  197   f - 7  to  197   f - 18 , respectively. Specifically, one signals dSI 7 +, dSI 8 +, dSI 9 +, dSI 10 +, dSI 11 +, and dSI 12 + of the pair of differential print data signals dSI 7  to dSI 12  are propagated in the wirings  197   f - 7 ,  197   f - 9 ,  197   f - 11 ,  197   f - 13 ,  197   f - 15 , and  197   f - 17 , respectively. The signal dSI 7 +, dSI 8 +, dSI 9 +, dSI 10 +, dSI 11 +, and dSI 12 + are input to the restoration circuit  130  through contact portions  180   f - 7 ,  180   f - 9 ,  180   f - 11 ,  180   f - 13 ,  180   f - 15 , and  180   f - 17  and the terminals  353   f - 7 ,  353   f - 9 ,  353   f - 11 ,  353   f - 13 ,  353   f - 15 , and  353   f - 17  in the liquid discharge head  21 . The other signals signal dSI 7 −, dSI 8 −, dSI 9 −, dSI 10 −, dSI 11 −, and dSI 12 − of the pair of differential print data signals dSI 7  to dSI 12  are propagated in the wirings  197   f - 8 ,  197   f - 10 ,  197   f - 12 ,  197   f - 14 ,  197   f - 16 , and  197   f - 18 , respectively. The signal dSI 7 −, dSI 8 −, dSI 9 −, dSI 10 −, dSI 11 −, and dSI 12 − are input to the restoration circuit  130  through contact portions  180   f - 8 ,  180   f - 10 ,  180   f - 12 ,  180   f - 14 ,  180   f - 16 , and  180   f - 18  and the terminals  353   f - 8 ,  353   f - 10 ,  353   f - 12 ,  353   f - 14 ,  353   f - 16 , and  353   f - 18  in the liquid discharge head  21 . 
     The base latch signal oLAT is propagated in wiring  197   f - 20 . The base latch signal oLAT is input to the restoration circuit  130  through a contact portion  180   f - 20  and the terminal  353   f - 20  in the liquid discharge head  21 . The base change signal oCHa is propagated in wiring  197   f - 22 . The base change signal oCHa is input to the restoration circuit  130  through a contact portion  180   f - 22  and the terminal  353   f - 22  in the liquid discharge head  21 . The base change signal oCHb is propagated in wiring  197   f - 23 . The base change signal oCHb is input to the restoration circuit  130  through a contact portion  180   f - 23  and the terminal  353   f - 23  in the liquid discharge head  21 . 
     The ground signal GND 1  is propagated in wirings  197   f - 19  and  197   f - 21 . The ground signal GND 1  is input to the driving signal selection circuits  200 - 1  to  200 - 12  through contact portions  180   f - 19  and  180   f - 21  and the terminals  353   f - 19  and  353   f - 21  in the liquid discharge head  21 . The ground signal GND 2  is propagated in wirings  197   f - 3  and  197   f - 6 . The ground signal GND 2  is input to the restoration circuit  130  through contact portions  180   f - 3  and  180   f - 6  and the terminals  353   f - 3  and  353   f - 6  in the liquid discharge head  21 . 
     The cable  19   f  is used for propagating a plurality of control signals such as a signal NVTS for detecting a discharge state of an ink from the liquid discharge head  21 , a signal TSIG for defining a detection timing of the discharge state of the ink by the signal NVTS, and a signal NCHG for forcibly driving the plurality of piezoelectric elements  60  in the liquid discharge head  21 . The plurality of control signals such as the signals NVTS, TSIG, and NCHG are input to the liquid discharge head  21  through the connector  350   f.    
       FIG. 23  is a diagram illustrating details of a signal which is propagated in the cable  19   g  and is input to the liquid discharge head  21  through the connector  350   g .  FIG. 24  is a diagram illustrating details of a signal which is propagated in the cable  19   h  and is input to the liquid discharge head  21  through the connector  350   g . As illustrated in  FIGS. 23 and 24 , the cable  19   g  and the cable  19   h  are used for propagating the driving signals COMA 1  to COMA 6  and COMB 1  to COMB 6  (being bases of the driving signals VOUT 1  to VOUT 6  to be supplied to one ends of the piezoelectric elements  60  included in the nozzle lines L 1   a  to L 1   f ) and the voltage VBS 1  to VBS 6  (to be supplied to the other ends of the piezoelectric elements  60 ). 
     Specifically, the driving signal COMA 1  being the base of the driving signal VOUT 1  to be supplied to one end of the piezoelectric element  60  included in the nozzle line L 1   a  is propagated in wirings  197   h - 22  and  197   h - 24 . The driving signal COMA 1  is input to the driving signal selection circuit  200 - 1  through contact portions  180   h - 22  and  180   h - 24 , and the terminals  353   h - 22  and  353   h - 24 . The driving signal COMB 1  being the base of the driving signal VOUT 1  is propagated in wirings  197   g - 2  and  197   g - 4 . The driving signal COMB 1  is input to the driving signal selection circuit  200 - 1  through contact portions  180   g - 2  and  180   g - 4  and the terminals  353   g - 2  and  353   g - 4 . The voltage VBS 1  is propagated in wirings  197   g - 1 ,  197   g - 3 ,  197   h - 21 , and  197   h - 23 . The voltage VBS 1  is supplied to the other end of the piezoelectric element  60  through contact portions  180   g - 1 ,  180   g - 3 ,  180   h - 21 , and  180   h - 23  and the terminals  353   g - 1 ,  353   g - 3 ,  353   h - 21 , and  353   h - 23 . 
     The driving signal COMA 2  being the base of the driving signal VOUT 2  to be supplied to one end of the piezoelectric element  60  included in the nozzle line L 1   b  is propagated in wirings  197   g - 6  and  197   g - 8 . The driving signal COMA 2  is input to the driving signal selection circuit  200 - 2  through contact portions  180   g - 6  and  180   g - 8  and the terminals  353   g - 6  and  353   g - 8 . The driving signal COMB 2  being the base of the driving signal VOUT 2  is propagated in wirings  197   h - 18  and  197   h - 20 . The driving signal COMB 2  is input to the driving signal selection circuit  200 - 2  through contact portions  180   h - 18  and  180   h - 20 , and the terminals  353   h - 18  and  353   h - 20 . The voltage VBS 2  is propagated in wirings  197   g - 5 ,  197   g - 7 ,  197   h - 17 , and  197   h - 19 . The voltage VBS 2  is supplied to the other end of the piezoelectric element  60  through contact portions  180   g - 5 ,  180   g - 7 ,  180   h - 17 , and  180   h - 19  and the terminals  353   g - 5 ,  353   g - 7 ,  353   h - 17 , and  353   h - 19 . 
     The driving signal COMA 3  being the base of the driving signal VOUT 3  to be supplied to one end of the piezoelectric element  60  included in the nozzle line L 1   c  is propagated in wirings  197   h - 14  and  197   h - 16 . The driving signal COMA 3  is input to the driving signal selection circuit  200 - 3  through contact portions  180   h - 14  and  180   h - 16 , and the terminals  353   h - 14  and  353   h - 16 . The driving signal COMB 3  being the base of the driving signal VOUT 3  is propagated in wirings  197   g - 10  and  197   g - 12 . The driving signal COMB 3  is input to the driving signal selection circuit  200 - 3  through contact portions  180   g - 10  and  180   g - 12  and the terminals  353   g - 10  and  353   g - 12 . The voltage VBS 3  is propagated in wirings  197   g - 9 ,  197   g - 11 ,  197   h - 13 , and  197   h - 15 . The voltage VBS 3  is supplied to the other end of the piezoelectric element  60  through contact portions  180   g - 9 ,  180   g - 11 ,  180   h - 13 , and  180   h - 15  and the terminals  353   g - 9 ,  353   g - 11 ,  353   h - 13 , and  353   h - 15 . 
     The driving signal COMA 4  being the base of the driving signal VOUT 4  to be supplied to one end of the piezoelectric element  60  included in the nozzle line L 1   d  is propagated in wirings  197   g - 14  and  197   g - 16 . The driving signal COMA 4  is input to the driving signal selection circuit  200 - 4  through contact portions  180   g - 14  and  180   g - 16  and the terminals  353   h - 14  and  353   h - 16 . The driving signal COMB 4  being the base of the driving signal VOUT 4  is propagated in wirings  197   h - 10  and  197   h - 12 . The driving signal COMB 4  is input to the driving signal selection circuit  200 - 4  through contact portions  180   h - 10  and  180   h - 12 , and the terminals  353   h - 10  and  353   h - 12 . The voltage VBS 4  is propagated in wirings  197   g - 13 ,  197   g - 15 ,  197   h - 9 , and  197   h - 11 . The voltage VBS 4  is supplied to the other end of the piezoelectric element  60  through contact portions  180   g - 13 ,  180   g - 15 ,  180   h - 9 , and  180   h - 11  and the terminals  353   g - 13 ,  353   g - 15 ,  353   h - 9 , and  353   h - 11 . 
     The driving signal COMA 5  being the base of the driving signal VOUT 5  to be supplied to one end of the piezoelectric element  60  included in the nozzle line L 1   e  is propagated in wirings  197   h - 6  and  197   h - 8 . The driving signal COMA 5  is input to the driving signal selection circuit  200 - 5  through contact portions  180   h - 6  and  180   h - 8 , and the terminals  353   h - 6  and  353   h - 8 . The driving signal COMB 5  being the base of the driving signal VOUT 5  is propagated in wirings  197   g - 18  and  197   g - 20 . The driving signal COMB 5  is input to the driving signal selection circuit  200 - 5  through contact portions  180   g - 18  and  180   g - 20  and the terminals  353   g - 18  and  353   g - 20 . The voltage VBS 5  is propagated in wirings  197   g - 17 ,  197   g - 19 ,  197   h - 5 , and  197   h - 7 . The voltage VBS 5  is supplied to the other end of the piezoelectric element  60  through contact portions  180   g - 17 ,  180   g - 19 ,  180   h - 5 , and  180   h - 7  and the terminals  353   g - 17 ,  353   g - 19 ,  353   h - 5 , and  353   h - 7 . 
     The driving signal COMA 6  being the base of the driving signal VOUT 6  to be supplied to one end of the piezoelectric element  60  included in the nozzle line L 1   f  is propagated in wirings  197   g - 22  and  197   g - 24 . The driving signal COMA 6  is input to the driving signal selection circuit  200 - 6  through contact portions  180   g - 22  and  180   g - 24  and the terminals  353   h - 22  and  353   h - 24 . The driving signal COMB 6  being the base of the driving signal VOUT 6  is propagated in wirings  197   h - 2  and  197   h - 4 . The driving signal COMB 6  is input to the driving signal selection circuit  200 - 6  through contact portions  180   h - 2  and  180   h - 4 , and the terminals  353   h - 2  and  353   h - 4 . The voltage VBS 6  is propagated in wirings  197   g - 22 ,  197   g - 24 ,  197   h - 2 , and  197   h - 4 . The voltage VBS 6  is supplied to the other end of the piezoelectric element  60  through contact portions  180   g - 22 ,  180   g - 24 ,  180   h - 2 , and  180   h - 4  and the terminals  353   g - 22 ,  353   g - 24 ,  353   h - 2 , and  353   h - 4 . 
     1.7. Advantageous Effects 
     In the liquid discharge apparatus  1 , the liquid discharge head control circuit  15 , and the liquid discharge head  21  configured in a manner as described above, the clock signal among the plurality of control signals for controlling the liquid discharge head  21  is converted into the pair of differential clock signals dSCK, and is propagated from the liquid discharge head control circuit  15  to the liquid discharge head  21 . In this case, the wiring  197   b - 4 , the terminal  353   b - 4 , and the contact portion  180   b - 4  for propagating the signal dSCK+ being the one signal of the pair of differential clock signals dSCK are located to be adjacent to the wiring  197   b - 3 , the terminal  353   b - 3 , and the contact portion  180   b - 3  for propagating the ground signal GND 2  of the restoration circuit  130  that restores the pair of differential clock signals dSCK to the clock signal SCK. In addition, the wiring  197   b - 5 , the terminal  353   b - 5 , and the contact portion  180   b - 5  for propagating the signal dSCK− being the other signal of the pair of differential clock signals dSCK are located to be adjacent to the wiring  197   b - 6 , the terminal  353   b - 6 , and the contact portion  180   b - 5  for propagating the ground signal GND 2  of the restoration circuit  130 . Thus, it is possible to reduce a propagation path in which the pair of differential clock signals dSCK are propagated to the restoration circuit  130 . In addition, it is possible to reduce a concern that the pair of differential clock signals dSCK are distorted, and to reduce a concern that external noise is superimposed on the pair of differential clock signals dSCK. 
     2. Second Embodiment 
     A liquid discharge apparatus  1 , a liquid discharge head control circuit  15 , and a liquid discharge head  21  according to a second embodiment will be described. The liquid discharge head control circuit  15  in the second embodiment is different from the liquid discharge head control circuit  15  in the first embodiment in that the wiring  197   b - 4  adjacent to the wiring  197   b - 3  in which the ground signal GND 2  to be supplied to the restoration circuit  130  is propagated is used for propagating one signal dSI 1 + of the pair of differential print data signals dSI 1 , and the wiring  197   b - 5  adjacent to the wiring  197   b - 6  in which the ground signal GND 2  is propagated is used for propagating the other signal dSI 1 − of the pair of differential print data signals dSI 1 . 
     The liquid discharge head  21  in the second embodiment is different from the liquid discharge head  21  in the first embodiment in that the one signal dSI 1 + of the pair of differential print data signals dSI 1  is input to the terminal  353   b - 4  adjacent to the terminal  353   b - 3  to which the ground signal GND 2  to be supplied to the restoration circuit  130  is input, and the other signal dSI 1 − of the pair of differential print data signals dSI 1  is input to the terminal  353   b - 5  adjacent to the terminal  353   b - 6  to which the ground signal GND 2  is input. 
     The liquid discharge apparatus  1  in the second embodiment is different from the liquid discharge apparatus  1  in the first embodiment in that the one signal dSI 1 + of the pair of differential print data signals dSI 1  is input to the contact portion  180   b - 4  adjacent to the contact portion  180   b - 3  to which the ground signal GND 2  to be supplied to the restoration circuit  130  is input, and the other signal dSI 1 − of the pair of differential print data signals dSI 1  is input to the contact portion  180   b - 5  adjacent to the contact portion  180   b - 6  to which the ground signal GND 2  is input. 
     When the liquid discharge apparatus  1 , the liquid discharge head control circuit  15 , and the liquid discharge head  21  according to the second embodiment will be described, the same components as those in the first embodiment are denoted by the same reference signs, and descriptions of the same components as those in the first embodiment will not be repeated. 
       FIG. 25  is a diagram illustrating details of a signal which is propagated in the cable  19   b  and is input to the liquid discharge head  21  through the connector  350   b  according to the second embodiment. As illustrated in  FIG. 25 , in the liquid discharge head control circuit  15  in the second embodiment, the wiring  197   b - 4  for propagating one signal dSI 1 + of the pair of differential print data signals dSI 1  is located to be adjacent to the wiring  197   b - 3  in which the ground signal GND 2  to be supplied to the restoration circuit  130  is propagated. The wiring  197   b - 5  for propagating the other signal dSI 1 − of the pair of differential print data signals dSI 1  is located to be adjacent to the wiring  197   b - 6  in which the ground signal GND 2  to be supplied to the restoration circuit  130  is propagated. 
     In the liquid discharge head  21  in the second embodiment, the terminal  353   b - 4  to which the one signal dSI 1 + of the pair of differential print data signals dSI 1  is input is located to be adjacent to the terminal  353   b - 3  to which the ground signal GND 2  to be supplied to the restoration circuit  130  is input. The terminal  353   b - 5  to which the other signal dSI 1 − of the pair of differential print data signals dSI 1  is input is located to be adjacent to the terminal  353   b - 6  to which the ground signal GND 2  to be supplied to the restoration circuit  130  is input. 
     In the liquid discharge apparatus  1  in the second embodiment, the contact portion  180   b - 4  to which the one signal dSI 1 + of the pair of differential print data signals dSI 1  is input is located to be adjacent to the contact portion  180   b - 3  to which the ground signal GND 2  to be supplied to the restoration circuit  130  is input. The contact portion  180   b - 5  to which the other signal dSI 1 − of the pair of differential print data signals dSI 1  is input is located to be adjacent to the contact portion  180   b - 6  to which the ground signal GND 2  to be supplied to the restoration circuit  130  is input. 
     In the liquid discharge head control circuit  15  configured as described above in the second embodiment, similar to the first embodiment, the wirings  197   b - 3  and  197   b - 6  in which the ground signal GND 2  is propagated are disposed to be adjacent to both sides of the wirings  197   b - 4  and  197   b - 5  in which the differential print data signal dSI 1  are propagated, and thus the wirings  197   b - 3  and  197   b - 6  function as shield wirings. Thus, it is possible to reduce the concern that external noise is superimposed on the differential print data signal dSI 1 . Further, since the ground signal GND 2  to be supplied to the restoration circuit  130  is used as a ground for shielding the differential print data signal dSI 1 , it is possible to reduce a current path generated based on the differential print data signal dSI 1 . Accordingly, it is possible to reduce distortion of a waveform occurring in the differential print data signal dSI 1 . 
     Similarly, in the liquid discharge head  21  in the second embodiment, similar to the first embodiment, the terminals  353   b - 3  and  353   b - 6  to which the ground signal GND 2  is input are disposed to be adjacent to both sides of the terminals  353   b - 4  and  353   b - 5  to which the differential print data signal dSI 1  is input, and thus the terminals  353   b - 3  and  353   b - 6  function as shield terminals. Thus, it is possible to reduce the concern that external noise is superimposed on the differential print data signal dSI 1 . Further, since the ground signal GND 2  to be supplied to the restoration circuit  130  is used as a ground for shielding the differential print data signal dSI 1 , it is possible to reduce a current path generated based on the differential print data signal dSI 1 . Accordingly, it is possible to reduce distortion of a waveform occurring in the differential print data signal dSI 1 . 
     Similarly, in the liquid discharge apparatus  1  in the second embodiment, similar to the first embodiment, the contact portions  180   b - 3  and  180   b - 6  to which the ground signal GND 2  is input are disposed to be adjacent to both sides of the contact portions  180   b - 4  and  180   b - 5  to which the differential print data signal dSI 1  is input, and thus the contact portions  180   b - 3  and  180   b - 6  function as shields. Thus, it is possible to reduce the concern that external noise is superimposed on the differential print data signal dSI 1 . Further, since the ground signal GND 2  to be supplied to the restoration circuit  130  is used as a ground for shielding the differential print data signal dSI 1 , it is possible to reduce a current path generated based on the differential print data signal dSI 1 . Accordingly, it is possible to reduce distortion of a waveform occurring in the differential print data signal dSI 1 . 
     3. Third Embodiment 
     A liquid discharge apparatus  1 , a liquid discharge head control circuit  15 , and a liquid discharge head  21  according to a third embodiment will be described. The liquid discharge head control circuit  15  in the third embodiment is different from the liquid discharge head control circuit  15  in the first embodiment in that the wiring in which the differential signal is propagated and the wiring in which the ground signal GND 2  is propagated at least overlap each other in the X-direction. When the third embodiment will be described, descriptions will be made on the assumption that the differential signal propagated in the wiring facing the wiring in which the ground signal GND 2  is propagated is set to the differential clock signal dSCK. However, this differential signal may be the differential print data signal dSI 1 . 
     The liquid discharge head  21  in the third embodiment is different from the liquid discharge head  21  in the first embodiment in that the terminal to which the differential signal is input and the terminal to which the ground signal GND 2  is input are provided to at least overlap each other in the X-direction. The liquid discharge apparatus  1  in the third embodiment is different from the liquid discharge apparatus  1  in the first embodiment in that the contact portion to which the differential signal and the contact portion to which the ground signal GND 2  is input are provided to at least overlap each other in the X-direction. When the third embodiment will be described, descriptions will be made on the assumption that the differential signal input to the terminal and the contact portion which face the terminal and the contact portion to which the ground signal GND 2  is input is set to the differential clock signal dSCK. However, this differential signal may be the differential print data signal dSI 1 . 
     When the liquid discharge apparatus  1 , the liquid discharge head control circuit  15 , and the liquid discharge head  21  according to the third embodiment will be described, the same components as those in the first embodiment are denoted by the same reference signs, and descriptions of the same components as those in the first embodiment will not be repeated. 
       FIG. 26  is a diagram illustrating details of a signal which is propagated in the cable  19   a  and is input to the liquid discharge head  21  through the connector  350   a  according to the third embodiment.  FIG. 27  is a diagram illustrating details of a signal which is propagated in the cable  19   b  and is input to the liquid discharge head  21  through the connector  350   b  according to the third embodiment. Here, in the liquid discharge apparatus  1 , the liquid discharge head control circuit  15 , and the liquid discharge head  21  in the third embodiment, descriptions will be made on the assumption as follows. That is, the connector  350   a  and the connector  350   b  are provided such that each of the terminals  353   a - 1  to  353   a - p  in the connector  350   a  at least overlaps each of the terminals  353   b - 1  to  353   b - p  in the connector  350   b  when the head substrate  320  is viewed from the side  324  toward the side  323  in the X-direction, that is, when the head substrate  320  is viewed in a direction intersecting with a direction in which the terminals  353   a - 1  to  353   a - p  in the connector  350   a  are arranged in parallel. Specifically, the descriptions will be made on the assumption that the terminal  353   a - 1  in the connector  350   a  and the terminal  353   b - p  in the connector  350   b  are provided to at least overlap each other, and the terminal  353   a - j  (j is any of 1 to p) in the connector  350   a  and the terminal  353   b -((p+1)−j) in the connector  350   b  are provided to at least overlap each other. 
     As illustrated in  FIG. 26 , the cable  19   a  is used for propagating a plurality of control signals including the ground signals GND 1  and GND 2  and the voltage VHV to be supplied to the plurality of driving signal selection circuits  200 . Thus, the plurality of control signals propagated in the cable  19   a  are supplied to the liquid discharge head  21  through the connector  350   a.    
     Specifically, the ground signal GND 1  is propagated in each of the wirings  197   a - 2  and  197   a - 4  to  197   a - 19  and is input to the liquid discharge head  21  through each of the contact portions  180   a - 2  and  180   a - 4  to  180   a - 19  and each of the terminals  353   a - 3  and  353   a - 4  to  353   a - 19 . The ground signal GND 2  is propagated in each of the wirings  197   a - 20  and  197   a - 21  and is input to the liquid discharge head  21  through each of the contact portions  180   a - 20  and  180   a - 21  and each of the terminals  353   a - 20  and  353   a - 21 . The voltage VHV is propagated in the wiring  197   a - 1  and is input to the liquid discharge head  21  through the contact portion  180   a - 1  and the terminal  353   a - 1 . The voltage VDD is propagated in each of the wirings  197   a - 22  and  197   a - 23  and is input to the liquid discharge head  21  through each of the contact portions  180   a - 22  and  180   a - 23  and each of the terminals  353   a - 22  and  353   a - 23 . 
     As illustrated in  FIG. 27 , when the head substrate  320  is viewed from the side  324  toward the side  323  in the X-direction, the one signal dSCK+ in the differential clock signal dSCK is input to the terminal  353   b - 4  of the connector  350   b , which is provided to at least overlap the terminal  353   a - 21  of the connector  350   a , to which the ground signal GND 2  is input. The other signal dSCK− in the differential clock signal dSCK is input to the terminal  353   b - 5  of the connector  350   b , which is provided to at least overlap the terminal  353   a - 20  of the connector  350   a , to which the ground signal GND 2  is input. 
     That is, in the liquid discharge head  21  in the third embodiment, in the direction intersecting with the direction in which the terminal  353   b - 4  and the terminal  353   b - 5  are arranged, the terminal  353   a - 21  to which the ground signal GND 2  is input is located to overlap the terminal  353   b - 4  to which the one signal dSCK+ in the differential clock signal dSCK is input, and the terminal  353   a - 20  to which the ground signal GND 2  is input is located to overlap the terminal  353   b - 5  to which the other signal dSCK− in the differential clock signal dSCK is input. In other words, the ground signal GND 2  and the differential clock signal dSCK are input to the different connectors  350 . In the direction intersecting with the direction in which the terminal  353   b - 4  and the terminal  353   b - 5  are arranged, the terminal  353   a - 21  to which the ground signal GND 2  is input is located to face the terminal  353   b - 4  to which the one signal dSCK+ in the differential clock signal dSCK is input, and the terminal  353   a - 20  to which the ground signal GND 2  is input is located to face the terminal  353   b - 5  to which the other signal dSCK− in the differential clock signal dSCK is input. 
     Here, the phrase of being located to face is not limited to that a space is provided between the terminal  353   a - k  and the terminal  353   b - k . For example, the head substrate  320 , the housing  351  of the connector  350 , and the insulator  198  of the cable  19  may be interposed between the terminal  353   a - k  and the terminal  353   b - k . In other words, the phrase of being located to face means that another terminal  353  is not located between the terminal  353   a - k  and the terminal  353   b - k  when viewed from a specific direction. That is, the shortest distance between the terminal  353   a - 21  to which the ground signal GND 2  is input and the terminal  353   b - 4  to which the one signal dSCK+ in the differential clock signal dSCK is input is shorter than the shortest distance between the terminal  353   a - 21  and the terminal of the connector  350   a , to which the ground signal GND 1  is input. The shortest distance between the terminal  353   a - 20  to which the ground signal GND 2  is input and the terminal  353   b - 5  to which the other signal dSCK− in the differential clock signal dSCK is input is shorter than the shortest distance between the terminal  353   a - 20  and the terminal of the connector  350   a , to which the ground signal GND 1  is input. Here, the shortest distance means a spatial distance when the terminals  353  are joined to each other by a straight line. 
     In the liquid discharge head control circuit  15  in the third embodiment, in the direction intersecting with the direction in which the wiring  197   b - 4  and the wiring  197   b - 5  are arranged, the wiring  197   a - 21  in which the ground signal GND 2  is propagated is located to overlap the wiring  197   b - 4  in which the one signal dSCK+ in the differential clock signal dSCK is propagated. The wiring  197   a - 20  in which the ground signal GND 2  is propagated is located to overlap the wiring  197   b - 5  in which the other signal dSCK− in the differential clock signal dSCK is propagated. In other words, the ground signal GND 2  and the differential clock signal dSCK are propagated in the different cables  19 . In the direction intersecting with the direction in which the wiring  197   b - 4  and the wiring  197   b - 5  are arranged, the wiring  197   a - 21  in which the ground signal GND 2  is propagated is located to face the wiring  197   b - 4  in which the one signal dSCK+ in the differential clock signal dSCK is propagated. The wiring  197   a - 20  in which the ground signal GND 2  is propagated is located to face the wiring  197   b - 5  in which the other signal dSCK− in the differential clock signal dSCK is propagated. 
     Here, the phrase of being located to face is not limited to that a space is provided between the wiring  197   a - k  and the wiring  197   b - k . For example, the head substrate  320 , the housing  351  of the connector  350 , and the insulator  198  of the cable  19  may be interposed between the wiring  197   a - k  and the wiring  197   b - k.    
     That is, in the liquid discharge apparatus  1  in the third embodiment, in the direction intersecting with the direction in which the contact portion  180   b - 4  and the contact portion  180   b - 5  are arranged, the contact portion  180   a - 21  to which the ground signal GND 2  is input is located to overlap the contact portion  180   b - 4  to which the one signal dSCK+ in the differential clock signal dSCK is input. The contact portion  180   a - 20  to which the ground signal GND 2  is input is located to overlap the contact portion  180   b - 5  to which the other signal dSCK− in the differential clock signal dSCK is input. In other words, the ground signal GND 2  and the differential clock signal dSCK are input to the liquid discharge head  21  from the liquid discharge head control circuit  15  through the different contact portions  180 . In the direction intersecting with the direction in which the contact portion  180   b - 4  and the contact portion  180   b - 5  are arranged, the contact portion  180   a - 21  to which the ground signal GND 2  is input is located to face the contact portion  180   b - 4  to which the one signal dSCK+ in the differential clock signal dSCK is input, and the contact portion  180   a - 20  to which the ground signal GND 2  is input is located to face the contact portion  180   b - 5  to which the other signal dSCK− in the differential clock signal dSCK is input. 
     Here, the phrase of being located to face is not limited to that a space is provided between the contact portion  180   a - k  and the contact portion  180   b - k . For example, the head substrate  320 , the housing  351  of the connector  350 , and the insulator  198  of the cable  19  may be interposed between the contact portion  180   a - k  and the contact portion  180   b - k . In other words, the phrase of being located to face means that another contact portion  180  is not located between the contact portion  180   a - k  and the contact portion  180   b - k  when viewed from a specific direction. That is, the shortest distance between the contact portion  180   a - 21  to which the ground signal GND 2  is input and the contact portion  180   b - 4  to which the one signal dSCK+ in the differential clock signal dSCK is input is shorter than the shortest distance between the contact portion  180   a - 21  and the contact portion  180  to which the ground signal GND 1  is input. The shortest distance between the contact portion  180   a - 20  to which the ground signal GND 2  is input and the contact portion  180   b - 5  to which the other signal dSCK− in the differential clock signal dSCK is input is shorter than the shortest distance between the contact portion  180   a - 20  and the contact portion  180  to which the ground signal GND 1  is input. Here, the shortest distance means a spatial distance when the contact portions  180  are joined to each other by a straight line. 
     In the liquid discharge apparatus  1 , the liquid discharge head control circuit  15 , and the liquid discharge head  21  configured as described above in the third embodiment, the ground signal GND 2  to be supplied to the restoration circuit  130  is used as the ground disposed to face the differential clock signal dSCK. Thus, it is possible to reduce a current path generated based on the differential clock signal dSCK. Accordingly, it is possible to reduce distortion of a waveform occurring in the differential clock signal dSCK. 
     The wiring in which the ground signal GND 2  is propagated may be located to at least overlap the wiring in which the one signal dSCK+ in the differential clock signal dSCK is propagated. The wiring in which the ground signal GND 2  is propagated may be located to at least overlap the wiring in which the other signal dSCK− in the differential clock signal dSCK is propagated. The embodiments are not limited to the above-described arrangement of the connectors  350   a  and  350   b.    
     Hitherto, the embodiments and the modification examples are described. 
     However, the present disclosure is not limited to the above embodiments, and various forms can be made in a range without departing from the gist. For example, the embodiments may be appropriately combined. 
     The present disclosure includes the substantially same configurations (for example, configurations having the same functions, methods, and results, or configurations having the same objects and effects) as the configurations described in the embodiments. The present disclosure includes configurations in which non-essential components of the configurations described in the embodiments are replaced. The present disclosure includes configurations having the same advantageous effects as those of the configurations described in the embodiments or includes configurations capable of achieving the same object. The present disclosure includes configurations in which a known technique is added to the configurations described in the embodiments.