Patent Publication Number: US-10773519-B2

Title: Liquid ejecting apparatus

Description:
The present application is based on, and claims priority from JP Application Serial Number 2018-095925, filed May, 18, 2018, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a liquid ejecting apparatus. 
     2. Related Art 
     It is known that a piezoelectric element such as a piezo element is used in an ink jet printer that prints an image or a document by ejecting ink as a liquid. The piezoelectric element is disposed in correspondence with each of a plurality of nozzles in a print head. By driving each piezoelectric element in accordance with a drive signal, a predetermined amount of ink is ejected from the nozzle at a predetermined timing, and a dot is formed. From an electrical viewpoint, the piezoelectric element is a capacitive load such as a capacitor. Thus, it is necessary to supply a sufficient current in order to operate the piezoelectric element of each nozzle. Thus, the ink jet printer is configured such that the piezoelectric element is driven by causing a drive circuit to supply a high voltage drive signal amplified by an amplification circuit to the head. 
     JP-A-2003-226006 discloses an ink jet printer that executes printing by applying a drive signal to an upper electrode for a piezoelectric element including the upper electrode and a lower electrode, controlling displacement of the piezoelectric element by controlling the drive signal, and ejecting ink based on the displacement. In the ink jet printer disclosed in JP-A-2003-226006, the drive signal applied to the upper electrode is applied to the piezoelectric element through a flexible flat cable. 
     When the drive signal is applied to the piezoelectric element through the flexible flat cable as disclosed in JP-A-2003-226006, a distortion occurs in the signal waveform of the drive signal due to an inductance component or the like of the flexible flat cable. Consequently, ejecting accuracy may deteriorate. Thus, the inductance component occurring in the flexible flat cable is to be reduced. 
     The inductance component of the flexible flat cable includes a self-inductance component and a mutual inductance component. Particularly, the inductance value of the mutual inductance component fluctuates due to the effect of a signal propagated adjacent to the flexible flat cable. Thus a new concern arises such that the inductance value varies for each wire constituting the flexible flat cable, and a distortion of the waveform of the drive signal noticeably occurs in a specific wire that is likely to be affected by the mutual inductance in the flexible flat cable. 
     SUMMARY 
     According to an aspect of the present disclosure, there is provided a liquid ejecting apparatus including a first drive circuit, an ejecting head including a first ejecting unit ejecting a liquid by driving a first piezoelectric element and a second ejecting unit ejecting a liquid by driving a second piezoelectric element, a first cable including a first terminal from which a first drive signal input into one end of the first piezoelectric element from the first drive circuit is output, and a second terminal from which a first reference voltage signal input into another end of the first piezoelectric element is output, and a second cable including a third terminal from which a second drive signal input into one end of the second piezoelectric element from the first drive circuit is output, and a fourth terminal from which a second reference voltage signal input into another end of the second piezoelectric element is output. The first cable and the second cable are disposed to at least partially overlap with each other in a direction orthogonal to a direction in which the first terminal and the second terminal are lined up. The second terminal and the fourth terminal are disposed between the first terminal and the third terminal. 
     The liquid ejecting apparatus may further include a second drive circuit. The first cable may include a fifth terminal from which a third drive signal input into one end of the second piezoelectric element from the second drive circuit is output. The second cable may include a sixth terminal from which a fourth drive signal input into one end of the first piezoelectric element from the second drive circuit is output. 
     In the liquid ejecting apparatus, the second terminal may be disposed between the first terminal and the fifth terminal. The fourth terminal may be disposed between the third terminal and the sixth terminal. The first cable and the second cable may be disposed such that the second terminal and the sixth terminal at least partially overlap with each other, and the fourth terminal and the fifth terminal at least partially overlap with each other. 
     In the liquid ejecting apparatus, the first drive signal and the third drive signal may have different signal waveforms. 
     In the liquid ejecting apparatus, a maximum voltage of the first drive signal may be higher than a maximum voltage of the third drive signal. 
     According to another aspect of the present disclosure, there is provided a liquid ejecting apparatus including a first drive circuit, a second drive circuit, an ejecting head including a first ejecting unit ejecting a liquid by driving a first piezoelectric element and a second ejecting unit ejecting a liquid by driving a second piezoelectric element, and a cable electrically coupling the first drive circuit and the second drive circuit to the ejecting head. The cable includes a first terminal from which a first drive signal input into one end of the first piezoelectric element from the first drive circuit is output, a second terminal from which a first reference voltage signal input into another end of the first piezoelectric element is output, a third terminal from which a second drive signal input into one end of the second piezoelectric element from the first drive circuit is output, a fourth terminal from which a second reference voltage signal input into another end of the second piezoelectric element is output, a fifth terminal from which a third drive signal input into one end of the second piezoelectric element from the second drive circuit is output, and a sixth terminal from which a fourth drive signal input into one end of the first piezoelectric element from the second drive circuit is output. The second terminal and the fourth terminal are disposed between the first terminal and the third terminal. In a direction orthogonal to a direction in which the first terminal and the second terminal are lined up, the second terminal and the sixth terminal are disposed to at least partially overlap with each other, and the fourth terminal and the fifth terminal are disposed to at least partially overlap with each other. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic exterior view of a liquid ejecting apparatus. 
         FIG. 2  is a diagram schematically illustrating an internal configuration when the liquid ejecting apparatus is seen in a negative direction of a subscanning direction. 
         FIG. 3  is a block diagram illustrating an electrical configuration of the liquid ejecting apparatus. 
         FIG. 4  is a diagram illustrating a schematic configuration corresponding to an ejecting unit. 
         FIG. 5  is a diagram illustrating an ink ejecting surface on which nozzles included in a plurality of ejecting units are disposed in an ejecting head. 
         FIG. 6  is a diagram illustrating one example of drive signals. 
         FIG. 7  is a diagram illustrating one example of a drive signal. 
         FIG. 8  is a diagram illustrating a configuration of a drive signal selection circuit. 
         FIG. 9  is a diagram illustrating a decoding content in a decoder. 
         FIG. 10  is a diagram illustrating a configuration of a selection circuit. 
         FIG. 11  is a diagram for describing an operation of the drive signal selection circuit. 
         FIG. 12  is a diagram illustrating a circuit configuration of a drive circuit. 
         FIG. 13  is a diagram illustrating a configuration of a cable. 
         FIG. 14  is a diagram illustrating a coupling relationship among a control substrate, a drive circuit substrate, a head substrate, and a plurality of cables. 
         FIG. 15  is a diagram illustrating a specific example of a signal propagated through a cable. 
         FIG. 16  is a diagram illustrating a specific example of a signal propagated through a cable. 
         FIG. 17  is a diagram for describing mutual arrangement of the cables. 
         FIG. 18  is a diagram for describing an effect of decrease in mutual inductance. 
         FIG. 19  is a diagram illustrating a state where a cable of a second embodiment is applied. 
         FIG. 20  is a diagram illustrating one example of a state where the cable of the second embodiment is folded. 
         FIG. 21  is an enlarged diagram of part XXI in  FIG. 20 . 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, exemplary embodiments of the present disclosure will be described using the drawings. The used drawings are for convenience of description. The embodiments described below do not unduly limit the content of the present disclosure disclosed in the claims. In addition, not all configurations described below are essential constituents of the present disclosure. 
     1. First Embodiment 
     1.1 Summary of Liquid Ejecting Apparatus 
     A liquid ejecting apparatus of a first embodiment is an ink jet printer that forms a dot on a printing medium such as paper by ejecting ink (liquid) depending on image data supplied from an external host computer and prints an image including a text, a figure, and the like corresponding to the image data. In the following description, a large format printer that can perform serial printing on a medium having a short edge width of A3 (297 mm) or greater among ink jet printers will be described as an example. 
       FIG. 1  is a schematic exterior view of a liquid ejecting apparatus  1  in the first embodiment. The liquid ejecting apparatus  1  includes a main body  2  and a support stand  3  supporting the main body  2 . The following description will be provided by denoting a movement direction of a carriage  24  by a main scan direction X, a transport direction of a printing medium P by a subscanning direction Y, and a vertical direction by Z in the liquid ejecting apparatus  1 . In addition, in the following description, for the main scan direction X, the subscanning direction Y, and the vertical direction Z, the direction of an arrow illustrated in each drawing may be distinctively described as a positive direction, and a direction opposite to the arrow may be distinctively described as a negative direction. Specifically, in the main scan direction X, a direction in which the carriage  24  moves away from a home position described below is the positive direction, and the opposite direction is the negative direction. In addition, in the subscanning direction Y, a direction in which the printing medium P is transported downstream from upstream is the positive direction, and the opposite direction is the negative direction. In addition, in the vertical direction Z, a direction opposite to the direction of gravity is the positive direction, and the direction of gravity is the negative direction. 
     The main body  2  includes a supply unit  4  supplying the printing medium P such as a paper roll, a head unit  20  performing printing by ejecting ink drops to the printing medium P, a discharge unit  6  discharging the printing medium P subjected to printing by the head unit  20  to the outside of the main body  2 , an operation unit  7  performing an operation such as execution and stopping of printing, and an ink retention unit  8  retaining ink to be ejected. In addition, while illustration is not provided, a USB port and a power supply port are included on the rear surface of the main body  2 . That is, the liquid ejecting apparatus  1  is configured to be coupled to a computer or the like through the USB port. 
     The head unit  20  includes the carriage  24  and an ejecting head  21 . 
     The ejecting head  21  includes a plurality of nozzles ejecting ink. The nozzles are mounted on the carriage  24  to face the printing medium P. The ejecting head  21  ejects ink drops from the plurality of nozzles. Details of the ejecting head  21  will be described below. 
     The carriage  24  is supported by a carriage guide shaft  32  and reciprocates in the main scan direction X. At this point, the printing medium P is transported in the subscanning direction Y. That is, the liquid ejecting apparatus  1  in the present embodiment performs serial printing by causing the carriage  24  on which the ejecting head  21  ejecting ink drops is mounted to reciprocate in the main scan direction X. 
     A plurality of ink cartridges are attached to the ink retention unit  8 . Each ink cartridge is filled with ink of corresponding color. In  FIG. 1 , four ink cartridges corresponding to four colors of cyan (C), magenta (M), yellow (Y), and black (B) are illustrated. The ink cartridge is not limited to the present configuration. For example, five or more ink cartridges may be included in the ink retention unit  8 . In addition, ink cartridges corresponding to colors such as gray, green, and violet may be included. The ink with which the ink cartridge is filled is supplied to the ejecting head  21  through an ink tube  9 . The ink cartridge may be mounted on the carriage  24 . 
       FIG. 2  is a diagram schematically illustrating an internal configuration when the liquid ejecting apparatus  1  is seen in the negative direction of the subscanning direction Y. As illustrated in  FIG. 2 , the liquid ejecting apparatus  1  includes the head unit  20 , the carriage guide shaft  32 , a platen  33 , a capping mechanism  35 , and a maintenance mechanism  80 . 
     The head unit  20  reciprocates within a range of a movable range R along the carriage guide shaft  32  based on control of a carriage moving mechanism not illustrated. The ejecting head  21  that is disposed such that an ink ejecting surface faces the printing medium P is mounted on the carriage  24 . In addition, a head substrate  104  is mounted on the ejecting head  21 . 
     A roller, not illustrated, transporting the printing medium P in the subscanning direction Y is disposed in the platen  33 . In addition, the platen  33  holds the printing medium P when ink drops are ejected to the printing medium P. 
     The maximum width (hereinafter, referred to as the “maximum printing width”) in which serial printing can be performed in the liquid ejecting apparatus  1  corresponds to a platen width PW that is the width of the platen  33  in the main scan direction X. The platen width PW is set to be greater than a standard dimension Ws of a medium width W that is the width of the printing medium P in the main scan direction X in order to stably hold and transport the printing medium P. In the first embodiment, the platen width PW corresponding to the maximum printing width satisfies Ws&lt;PW≤Ws×1.15 with respect to the standard dimension Ws. 
     For example, the liquid ejecting apparatus  1  having 24 inches of the standard dimension Ws of the medium width W is a printer corresponding to 24 inches of the maximum printing width and is specifically a printer having the maximum printing width greater than 24 inches and less than or equal to 27.6 inches. In addition, the liquid ejecting apparatus  1  having 36 inches of the standard dimension Ws of the medium width W is a printer corresponding to 36 inches of the maximum printing width and is specifically a printer having the maximum, printing width greater than 36 inches and less than or equal to 41.4 inches. In addition, the liquid ejecting apparatus  1  having 44 inches of the standard dimension Ws of the medium width W is a printer corresponding to 44 inches of the maximum printing width and is specifically a printer having the maximum printing width greater than 44 inches and less than or equal to 50.6 inches. In addition, the liquid ejecting apparatus  1  having 64 inches of the standard dimension Ws of the medium width W is a printer corresponding to 64 inches of the maximum printing width and is specifically a printer having the maximum printing width greater than 64 inches and less than or equal to 73.6 inches. 
     In the movable range R of the head unit  20 , the capping mechanism  35  for sealing the ink ejecting surface on which the plurality of nozzles are disposed in the ejecting head  21  is disposed at the home position that is the start point of reciprocation of the head unit  20 . The home position is a position at which the head unit  20  waits when the liquid ejecting apparatus  1  does not execute printing. 
     In the movable range R of the head unit  20 , the maintenance mechanism  80  is disposed on the opposite side of the platen  33  from the home position. The maintenance mechanism  80  performs a maintenance process such as a cleaning process of drawing viscous ink, air bubbles, and the like by a tube pump (not illustrated) and a wiping process of wiping a foreign object such as paper dust clinging to the ink ejecting surface of the ejecting head  21  by a wiper. 
     In addition, the liquid ejecting apparatus  1  includes a control substrate  100 , a drive circuit substrate  101 , and a plurality of cables  19 . The control substrate  100  and the drive circuit substrate  101 , the drive circuit substrate  101  and the head substrate  104 , and the control substrate  100  and the head substrate  104  are electrically coupled to each other through one or the plurality of cables  19 . The head substrate  104  is supplied with various signals propagating the cable  19 . Ink is ejected from the plurality of nozzles formed on the ink ejecting surface of the ejecting head  21  based on various signals supplied to the head substrate  104 . Details of the signals propagated through the plurality of cables  19  will be described below. 
     1.2 Electrical Configuration of Liquid Ejecting Apparatus 
       FIG. 3  is a block diagram illustrating an electrical configuration of the liquid ejecting apparatus  1  according to the present embodiment. As described above, the liquid ejecting apparatus  1  includes the control substrate  100 , the drive circuit substrate  101 , and the head substrate  104 . As illustrated in  FIG. 3 , a control circuit  111 , a power supply circuit  112 , and a control signal transmission circuit  113  are disposed (mounted) in the control substrate  100 . 
     The control circuit  111  is implemented by a processor such as a microcomputer and generates various data and signals based on various signals such as the image data supplied from the host computer. 
     Specifically, based on various signals supplied from the host computer, the control circuit  111  generates digital data as the sources of drive signals COMA and COMB for driving a piezoelectric element  60  included in a plurality of ejecting units  600 . Specifically, the control circuit ill generates 2-bit drive data COMA_D 0  and COMA_D 1  as the digital data as the source of the drive signal COMA. The drive data COMA_D 0  and COMA_D 1  propagate through the cable  19  illustrated in  FIG. 2  and are supplied to a drive circuit  50   a  disposed in the drive circuit substrate  101 . Similarly, the control circuit  111  generates 2-bit drive data COMB_D 0  and COMB_D 1  as the digital data as the source of the drive signal COMB. The drive data COMB_D 0  and COMB_D 1  propagate through the cable  19  illustrated in  FIG. 2  and are supplied to a drive circuit  50   b  disposed in the drive circuit substrate  101 . 
     In addition, based on various signals supplied from the host computer, the control circuit  111  generates six printing data signals SI 1  to SI 6 , a latch signal LAT, a change signal CH, and a clock signal SCK as a plurality of kinds of control signals for controlling driving of the piezoelectric element  60  and supplies the control signals to the control signal transmission circuit  113 . 
     In addition, the control circuit ill performs a process of finding the current scan position of the carriage  24  illustrated in  FIG. 3  and driving a carriage motor, not illustrated, based on the scan position of the carriage  24 . Accordingly, reciprocation of the carriage  24  in the main scan direction X is controlled. In addition, the control circuit  111  performs a process of driving a transport motor not illustrated. Accordingly, movement of the printing medium P in the subscanning direction Y is controlled. Furthermore, the control circuit  111  causes the maintenance mechanism  80  illustrated in  FIG. 3  to execute the maintenance process such as the cleaning process and the wiping process. 
     Besides the above processes, the control circuit  111  may generate the drive data COMA_D 0  and COMA_D 1  and the drive data COMB_D 0  and COMB_D 1  in which the waveforms of the drive signals COMA and COMB are corrected depending on a temperature signal indicating the temperature of the ejecting head  21 . In addition, the control circuit ill may stop supplying the drive data COMA_D 0  and COMA_D 1  and the drive data COMB_D 0  and COMB_D 1  to the drive circuits  50   a  and  50   b  depending on a malfunction signal indicating a malfunction of the ejecting head  21 . 
     The control signal transmission circuit  113  converts the six printing data signals SI 1  to SI 6  supplied from the control circuit  111  into differential signals [SI 1 +, SI 1 −] to [SI 6 +, SI 6 −], respectively. In addition, the control signal transmission circuit  113  converts the latch signal LAT, the change signal CH, and the clock signal SCK supplied from the control circuit  111  into differential signals [LAT+, LAT−], [CH+, CH−], and [SCK+, SCK−], respectively. The differential signals [SI 1 +, SI 1 −] to [SI 6 +, SI 6 −], [LAT+, LAT−], [CH+, CH−], and [SCK+, SCK−] are transmitted to a control signal reception circuit  115  disposed in the head substrate  104  by propagating through the cable  19 . For example, the control signal transmission circuit  113  generates the differential signal of a low voltage differential signaling (LVDS) transfer type. The differential signal of the LVDS transfer type has an amplitude of approximately 350 mV. Thus, high speed data transfer can be implemented. The control signal transmission circuit  113  may generate the differential signal of various high speed transfer types such as low voltage positive emitter coupled logic (LVPECL) and current mode logic (CML) other than LVDS. 
     For example, the power supply circuit  112  generates a high voltage signal VHV of DC 42 V and a ground voltage signal GND having a ground potential. The high voltage signal VHV propagates through the cable  19  and is supplied to the drive circuits  50   a  and  50   b  disposed in the drive circuit substrate  101  and drive signal selection circuits  120   a  to  120   f  disposed in the head substrate  104 . In addition, the ground voltage signal GND propagates through the cable  19  and is supplied to each circuit disposed in the drive circuit substrate  101  and each circuit disposed in the head substrate  104 . 
     The two drive circuits  50   a  and  50   b  and a voltage conversion circuit  114  are disposed (mounted) in the drive circuit substrate  101 . 
     The voltage conversion circuit  114  is supplied with the high voltage signal VHV. For example, the voltage conversion circuit  114  converts the high voltage signal VHV into a low voltage signal VDD of DC 3.3 V. In addition, for example, the voltage conversion circuit  114  converts the high voltage signal VHV into a power supply voltage signal GVDD of DC 7.5 V and supplies the power supply voltage signal GVDD to the drive circuits  50   a  and  50   b . In addition, for example, the voltage conversion circuit  114  converts the high voltage signal VHV into a reference voltage signal VBS of DC 6 V. The reference voltage signal VBS may also be converted from the power supply voltage signal GVDD. 
     The drive circuit  50   a  generates the drive signal COMA based on the 2-bit drive data COMA_D 0  and COMA_D 1  supplied from the control circuit  111 . Similarly, the drive circuit  50   b  generate(c) the drive signal COMB based on the 2-bit drive data COMB_D 0  and COMB_D 1  supplied from the control circuit  111 . The only difference between the drive circuits  50   a  and  50   b  is the supplied drive data and the output drive signal. Circuit configurations may be the same. Accordingly, in the following description, the drive circuits  50   a  and  50   b  may be referred to as a drive circuit  50  when not necessary to distinguish the drive circuits  50   a  and  50   b . Details of the drive circuits  50   a  and  50   b  will be described below. 
     The drive signal COMA generated by the drive circuit  50   a  is divided into six drive signals COMA 1  to COMA 6  in the drive circuit substrate  101 . Similarly, the drive signal COMB generated by the drive circuit  50   b  is divided into six drive signals COMB 1  to COMB 6  in the drive circuit substrate  101 . In addition, the reference voltage signal VBS generated by the voltage conversion circuit  114  is divided into six reference voltage signals VBS 1  to VBS 6  In the drive circuit substrate  101 . The drive signals COMA 1  to COMA 6  output from the drive circuit substrate  101  are signals having the same waveform. The drive signals COMB 1  to COMB 6  are signals having the same waveform. The reference voltage signals VBS 1  to VBS 6  are signals having the same waveform. Accordingly, in the following description, the drive signals COMA 1  to COMA 6  may be referred to as the drive signal COMA when not necessary to distinguish the drive signals COMA 1  to COMA 6 . Similarly, the drive signals COMB 1  to COMB 6  may be referred to as the drive signal COMB when not necessary to distinguish the drive signals COMB 1  to COMB 6 . Similarly, the reference voltage signals VBS 1  to VBS 6  may be referred to as the reference voltage signal VBS when not necessary to distinguish the reference voltage signals VBS 1  to VBS 6 . 
     The drive signals COMA 1  to COMA 6  and COMB 1  to COMB 6  and the reference voltage signals VBS 1  to VBS 6  are supplied to the head substrate  104  by propagating through one or the plurality of cables  19 . 
     The six drive signal selection circuits  120   a  to  120   f  and the control signal reception circuit  115  are disposed (mounted) in the head substrate  104 . 
     The control signal reception circuit  115  receives the differential signals [SI 1 +, SI 1 −] to [SI 6 +, SI 6 −], [LAT+, LAT−], [CH+, CH−], and [SCK+, SCK−] transmitted from the control signal transmission circuit  113  and converts the differential signals into the single-ended printing data signals SI 1  to SI 6 , the latch signal LAT, the change signal CH, and the clock signal SCK by differentially amplifying each received differential signal. 
     The printing data signals SIX to SI 6  are supplied to the drive signal selection circuits  120   a  to  120   f , respectively. In addition, the latch signal LAT, the change signal CH, and the clock signal SCK are supplied to the drive signal selection circuits  120   a  to  120   f  in common. 
     The drive signal selection circuits  120   a  to  120   f  generate drive signals VOUT 1  to VOUT 6  by selecting or not selecting any of the drive signals COMA 1  to COMA 6  and COMB 1  to COMB 6  based on the printing data signals SI 1  to SI 6 , the clock signal SCK, the latch signal LAT, and the change signal CH. The drive signal selection circuits  120   a  to  120   f  supply the drive signals VOUT 1  to VOUT 6  to any of the plurality of ejecting units  600 . 
     Specifically, the drive signal selection circuit  120   a  outputs the drive signal VOUT 1  by selecting or not selecting the drive signals COMA 1  and COMB 1 . The drive signal VOUT 1  is supplied to one end of the piezoelectric element  60  included in each ejecting unit  600  disposed in correspondence. In addition, the reference voltage signal VBS 1  is supplied to another end of the piezoelectric element  60 . 
     In addition, the drive signal selection circuit  120   b  selects or does not select the drive signals COMA 2  and COMB 2  and outputs the drive signal VOUT 2 . The drive signal VOUT 2  is supplied to one end of the piezoelectric element  60  included in each ejecting unit  600  disposed in correspondence. In addition, the reference voltage signal VBS 2  is supplied to the ocher end of the piezoelectric element  60 . 
     In addition, the drive signal selection circuit  120   c  selects or does not select the drive signals COMA 3  and COMB 3  and outputs the drive signal VOUT 3 . The drive signal VOUT 3  is supplied to one end of the piezoelectric element  60  included in each ejecting unit  600  disposed in correspondence. In addition, the reference voltage signal VBS 3  is supplied to the other end of the piezoelectric element  60 . 
     In addition, the drive signal selection circuit  120   d  selects or does not select the drive signals COMA 4  and COMB 4  and outputs the drive signal VOUT 4 . The drive signal VOUT 4  is supplied to one end of the piezoelectric element  60  included in each ejecting unit  600  disposed in correspondence. In addition, the reference voltage signal VBS 4  is supplied to the other end of the piezoelectric element  60 . 
     In addition, the drive signal selection circuit  120   e  selects or does not select the drive signals COMA 5  and COMB 5  and outputs the drive signal VOUT 5 . The drive signal VOUT 5  is supplied to one end of the piezoelectric element  60  included in each ejecting unit  600  disposed in correspondence. In addition, the reference voltage signal VBS 5  is supplied to the other end of the piezoelectric element  60 . 
     In addition, the drive signal selection circuit  120   f  selects or does not select the drive signals COMA 6  and COMB 6  and outputs the drive signal VOUT 6 . The drive signal VOUT 6  is supplied to one end of the piezoelectric element  60  included in each ejecting unit  600  disposed in correspondence. In addition, the reference voltage signal VBS 6  is supplied to the other end of the piezoelectric element  60 . 
     As described above, the drive signals COMA 1  to COMA 6  and COMB 1  to COMB 6  are signals having the same waveform. Accordingly, the drive signals VOUT 1  to VOUT 6  generated by selecting or not selecting the drive signals COMA 1  to COMA 6  and COMB 1  to COMB 6  are ideal signals having the same waveform. Accordingly, in the following description, the drive signals VOUT 1  to VOUT 6  may be referred to as a drive signal VOUT when, not necessary to distinguish the drive signals VOUT 1  to VOUT 6 . 
     The drive signal selection circuits  120   a  to  120   f  may have the same circuit configuration. Accordingly, the drive signal selection circuits  120   a  to  120   o  may be referred to as a drive signal selection circuit  120  when not necessary to distinguish the drive signal selection circuits  120   a  to  120   f . In addition, details of the drive signal selection circuit  120  will be described below. 
     Each piezoelectric element  60  is displaced depending on a difference in potential between the drive signals VOUT 1  to VOUT 6  supplied to one end and the reference voltage signals VBS 1  to VBS 6  supplied to the other end. Ink corresponding to the displacement is ejected from the ejecting unit  600 . 
     In the liquid ejecting apparatus  1  described thus far, the drive circuit  50   a  is one example of a first drive circuit, and the drive circuit  50   b  is one example of a second drive circuit. In addition, in the drive signal COMA output by the drive circuit  50   a , the drive signal COMA 1  is one example of a first drive signal. The drive signal COMA 2  is one example of a second drive signal. In addition, in the drive signal COMB output by the drive circuit  50   b , the drive signal COMB 2  is one example of a third drive signal. The drive signal COMB 1  is one example of a fourth drive signal. In addition, in the reference voltage signal VBS, the reference voltage signal VBS 1  is one example of a first reference voltage signal, and the reference voltage signal VBS 2  is one example of a second reference voltage signal. 
     1.3 Configuration of Ejecting Unit 
     Next, a configuration of the ejecting unit  600  will be described.  FIG. 4  is a diagram illustrating a schematic configuration corresponding to one ejecting unit  600 . As illustrated in  FIG. 4 , the ejecting unit  600  and a reservoir  641  are included. 
     The reservoir  641  is disposed for each color of ink. Ink is introduced into the reservoir  641  from a supply port  661 . Ink is supplied to the supply port  661  from the ink retention unit  8  through the ink tube  9 . 
     The ejecting unit  600  includes the piezoelectric element  60 , a vibration plate  621 , a cavity  631  functioning as a pressure chamber, and a nozzle  651 . The vibration plate  621  functions as a diaphragm that is displaced (flexurally vibrates) by the piezoelectric element  60  disposed on its upper surface in  FIG. 4  and increases/decreases the internal capacity of the cavity  631  filled with ink. The nozzle  651  is an open hole unit that is disposed in a nozzle plate  632  and communicates with the cavity  631 . The cavity  631  is filled with ink in its inside, and the internal capacity of the cavity  631  is changed by displacement of the piezoelectric element  60 . The nozzle  651  communicates with the cavity  631  and ejects ink inside the cavity  631  as ink drops in response to a change in the internal capacity of the cavity  631 . That is, the ejecting head  21  includes the plurality of ejecting units  600  ejecting ink by driving the piezoelectric element  60 . 
     The piezoelectric element  60  illustrated in  FIG. 4  has a structure in which a piezoelectric body  601  is interposed between a pair of electrodes  611  and  612 . In the piezoelectric body  601  of this structure, a center part bends upward and downward along with the electrodes  611  and  612  and the vibration plate  621  with respect to both end parts in  FIG. 4  in response to voltages applied to the electrodes  611  and  612 . Specifically, the piezoelectric element  60  is configured to bend upward when the voltage of the drive signal VOUT is increased and bend downward when the voltage of the drive signal VOUT is decreased. In this configuration, when the piezoelectric element  60  bends upward, the internal capacity of the cavity  631  is increased. Thus, ink is drawn from the reservoir  641 . When the piezoelectric element  60  bends downward, the internal capacity of the cavity  631  is decreased. Thus, ink is ejected from the nozzle  651  depending on the degree of decrease. 
     The piezoelectric element  60  is not limited to the illustrated structure and may be of a type that can eject a liquid such as ink by deforming the piezoelectric element  60 . In addition, the piezoelectric element  60  may be configured to use not only the flexural vibration but also so-called longitudinal vibration. 
     The plurality of ejecting units  600  configured as described above are disposed in the ejecting head  21 .  FIG. 5  is a diagram illustrating the ink ejecting surface on which the nozzles  651  included in the plurality of ejecting units  600  are disposed in the ejecting head  21 . 
     As illustrated in  FIG. 5 , six nozzle plates  632  are linearly disposed in the main scan direction X on the ink ejecting surface of the ejecting head  21 . Two nozzle arrays  650  lined up in the subscanning direction Y are formed in each nozzle plate  632 . In each nozzle array  650 , the nozzles  651  are linearly disposed at a density of 300 or more per 1 inch at a predetermined pitch Py in the subscanning direction Y. In the two nozzle arrays  650  disposed in each nozzle plate  632 , total 600 or more nozzles  651  are formed in a relationship such that each nozzle  651  is shifted by half of the pitch Py in the subscanning direction Y. That is, total 3,600 or more nozzles are formed in the ejecting head  21 . In the following description, the two nozzle arrays  650  disposed in each nozzle plate  632  may be referred to as a nozzle group  660 . The nozzle groups  660  formed in the six nozzle plates  632  linearly disposed in the main scan direction X may be referred to as a first nozzle group  660   a  to a sixth nozzle group  660   f.    
     The drive signals VOUT 1  to VOUT 6  described above are supplied in correspondence to the first nozzle group  660   a  to the sixth nozzle, group  660   f , respectively. Specifically, the drive signal VOUT 1  is supplied to one end of the piezoelectric element  60  included in the ejecting unit  600  disposed in correspondence with the nozzle  651  included in the first nozzle group  660   a . The reference voltage signal VBS 1  is supplied to the other end of each piezoelectric element  60  disposed in the first nozzle group  660   a . In addition, the drive signal VOUT 2  is supplied to one end of the piezoelectric element  60  included in the ejecting unit  600  disposed in correspondence with the nozzle  651  included in the second nozzle group  660   b . The reference voltage signal VBS 2  is supplied to the other end of each piezoelectric element  60  disposed in the second nozzle group  660   b . In addition, the drive signal VOUT 3  is supplied to one end of the piezoelectric element  60  included in the ejecting unit  600  disposed in correspondence with the nozzle  651  included in the third nozzle group  660   c . The reference voltage signal VBS 3  is supplied to the other end of each piezoelectric element  60  disposed in the third nozzle group  660   c . In addition, the drive signal VOUT 4  is supplied to one end of the piezoelectric element  60  included in the ejecting unit  600  disposed in correspondence with the nozzle  651  included in the fourth nozzle group  660   d . The reference voltage signal VBS 4  is supplied to the other end of each piezoelectric element  60  disposed in the fourth nozzle group  660   d . In addition, the drive signal VOUT 5  is supplied to one end of the piezoelectric element  60  included in the ejecting unit  600  disposed in correspondence with the nozzle  651  included in the fifth nozzle group  660   e . The reference voltage signal VBS 5  is supplied to the other end of each piezoelectric element  60  disposed in the fifth nozzle group  660   e . In addition, the drive signal VOUT 6  is supplied to one end of the piezoelectric element  60  included in the ejecting unit  600  disposed in correspondence with the nozzle  651  included in the sixth nozzle group  660   f . The reference voltage signal VBS 6  is supplied to the other end of each piezoelectric element  60  disposed in the sixth nozzle group  660   f.    
     The ejecting unit  600  corresponding to the nozzle  651  disposed in the first nozzle group  660   a  among the plurality of nozzle groups  660  disposed in the ejecting head  21  as described above is one example of a first ejecting unit. The piezoelectric element  60  included in the ejecting unit  600  is one example of a first piezoelectric element. Similarly, the ejecting unit  600  corresponding to the nozzle  651  disposed in the second nozzle group  660   b  is one example of a second ejecting unit. The piezoelectric element  60  included in the ejecting unit  600  is one example of a second piezoelectric element. 
     1.4 Configuration of Drive Signal 
     Methods for supplying the drive signal VOUT to the piezoelectric element  60  and forming a dot on the printing medium P include not only a method of forming one dot by ejecting an ink drop once but also a method (second method) of enabling two or more ejections of ink drops in a unit period and forming one dot by causing one or more ink drops ejected in the unit period to hit the printing medium P and combining the one or more hit ink drops, and a method (third method) of forming two or more dots without combining two or more ink drops. In the first embodiment, four shades of “large dot”, “medium dot”, “small dot”, and “no recording (no dot)” are represented by ejecting ink at most twice for one dot using the second method. 
     In the first embodiment, four shades of “large dot”, “medium dot”, “small dot”, and “no recording (no dot)” are represented using two kinds of drive signals COMA and COMB. Specifically, the drive signals COMA and COMB are set to have a first half pattern and a second half pattern in their one cycle. The drive signals COMA and COMB are selected or net selected in the first half and the second half of one cycle depending on the shade to be represented, and the drive signal VOUT is generated. 
       FIG. 6  is a diagram illustrating one example of the drive signals COMA and COMB. As illustrated in  FIG. 6 , the drive signal COMA has a waveform in which a trapezoidal waveform Adp 1  arranged in a period T 1  from a rise of the latch signal LAT until a rise of the change signal CH and a trapezoidal waveform Adp 2  arranged in a period T 2  from the rise of the change signal CH until a rise of the latch signal LAT are consecutive. A period including the period T 1  and the period T 2  is a cycle Ta. For each cycle Ta, a new dot is formed on the printing medium P. In the first embodiment, the trapezoidal waveforms Adp 1  and Adp 2  have almost the same waveform. When each of the trapezoidal waveforms Adp 1  and Adp 2  is supplied to one end of the piezoelectric element  60 , a predetermined amount of ink, specifically, approximately a medium amount, is ejected from the nozzle  651  corresponding to the piezoelectric element  60 . 
     The drive signal COMB has a waveform in which a trapezoidal waveform Bdp 1  arranged in the period T 1  and a trapezoidal waveform Bdp 2  arranged in the period T 2  are consecutive. The trapezoidal waveforms Bdp 1  and Bdp 2  are waveforms different from each other. Of the trapezoidal waveforms Bdp 1  and Bdp 2 , the trapezoidal waveform Bdp 1  is a waveform for preventing an increase in the viscosity of ink by providing micro-vibration to the ink around the open hole unit of the nozzle  651 . When the trapezoidal waveform Bdp 1  is supplied to one end of the piezoelectric element  60 , ink drops are not ejected from the nozzle  651  corresponding to the piezoelectric element  60 . In addition, the trapezoidal waveform Bdp 2  is a waveform different from the trapezoidal waveforms Adp 1  and Adp 2  and the trapezoidal waveform Bdp 1 . When the trapezoidal waveform Bdp 2  is supplied to one end of the piezoelectric element  60 , a smaller amount of ink than the predetermined amount is ejected from the nozzle  651  corresponding to the piezoelectric element  60 . 
     Any of the voltages at the start timings and the end timings of the trapezoidal waveforms Adp 1 , Adp 2 , Bdp 1 , and Bdp 2  is equal to a voltage Vc. That is, each of the trapezoidal waveforms Adp 1 , Adp 2 , Bdp 1 , and Bdp 2  is a waveform that starts at the voltage Vc and ends at the voltage Vc. 
     The drive signal COMA and the drive signal COMB have different signal waveforms. The maximum voltage of the drive signal COMA is higher than the maximum voltage of the drive signal COMB. 
       FIG. 7  is a diagram illustrating one example of the drive signal VOUT corresponding to each of “large dot”, “medium act”, “small dot”, and “no recording”. 
     As illustrated in  FIG. 7 , the drive signal VOUT corresponding to “large dot” has a waveform in which the trapezoidal waveform Adp 1  of the drive signal COMA in the period T 1  and the trapezoidal waveform Adp 2  of the drive signal COMA in the period T 2  are consecutive. When the drive signal VOUT is supplied to one end of the piezoelectric element  60 , approximately a medium amount of ink is ejected in two ejections from the nozzle  651  corresponding to the piezoelectric element  60  in the cycle Ta. Thus, each ink hits the printing medium P and combines to form a large dot. 
     The drive signal VOUT corresponding to “medium dot” has a waveform in which the trapezoidal waveform Adp 1  of the drive signal COMA in the period T 1  and the trapezoidal waveform Bdp 2  of the drive signal COMB in the period T 2  are consecutive. When the drive signal VOUT is supplied to one end of the piezoelectric element  60 , approximately a medium amount or approximately a small amount of ink is ejected in two ejections from the nozzle  651  corresponding to the piezoelectric element  60  in the cycle Ta. Thus, each ink hits the printing medium P and combines to form a medium dot. 
     The drive signal VOUT corresponding to “small doc” has a waveform in which the immediately previous voltage Vc held by the capacitance of the piezoelectric element  60  in the period T 1  and the trapezoidal waveform Bdp 2  of the drive signal COMB in the period T 2  are consecutive. When the drive signal VOUT is supplied to one end of the piezoelectric element  60 , approximately a small amount of ink is ejected from the nozzle  651  corresponding to the piezoelectric element  60  in only the period T 2  in the cycle Ta. Thus, the ink hits the printing medium P and forms a small dot. 
     The drive signal VOUT corresponding to “no recording” has a waveform in which the trapezoidal waveform Bdp 1  of the drive signal COMB in the period T 1  and the immediately previous voltage Vc held by the capacitance of the piezoelectric element  60  in the period T 2  are consecutive. When the drive signal VOUT is supplied to one end of the piezoelectric element  60 , only micro-vibration is provided to the nozzle  651  corresponding to the piezoelectric element  60  in the period T 2 , and ink is not ejected in the cycle Ta. Thus, ink does not hit the printing medium P, and a dot is not formed. 
     The drive signals COMA and COMB and the drive signal VOUT illustrated in  FIG. 6  and  FIG. 7  are merely one example. A combination of various waveforms prepared in advance is used depending on the moving speed of the head unit  20 , properties of the printing medium P, and the like. 
     1.5 Configuration of Drive Signal Selection Circuit 
     A configuration of the drive signal selection circuit  120  generating the drive signal VOUT by selecting or not selecting the drive signals COMA and COMB will be described. In the following description, the printing data signals SI 1  to SI 6  supplied to the drive signal selection circuit  120  will be referred to as a printing data signal SI. 
       FIG. 8  is a diagram illustrating a configuration of the drive signal selection circuit  120 . As illustrated in  FIG. 8 , the drive signal selection circuit  120  includes a selection control circuit  220  and a plurality of selection circuits  230 . 
     The selection control circuit  220  is supplied with the clock signal SCK, the printing data signal SI, the latch signal LAT, and the change signal CH. In addition, a set of a shift register (S/R)  222 , a latch circuit  224 , and a decoder  226  is disposed in the selection control circuit  220  in correspondence with each ejecting unit  600 . That is, one drive signal selection circuit  120  includes the same number of sets of the shift register  222 , the latch circuit  224 , and the decoder  226  as a total number m of nozzles  651  or piezoelectric elements  60  included in the nozzle group  660 . 
     The printing data signal SI is a total 2m-bit signal including 2-bit printing data [SIH, SIL] for selecting any of “large dot”, “medium dot”, “small dot”, and “no recording” for each of m ejecting units  600 . The printing data signal SI is a signal in synchronization with the clock signal SCK. The printing data signal SI is temporarily held in the shift register  222  in correspondence with the nozzle  651  for each 2-bit printing data [SIH, SIL] included in the printing data signal SI. Specifically, m stages of shift registers  222  corresponding to the piezoelectric elements  60  are coupled to each other in cascade, and the serially supplied printing data signal SI is sequentially transferred to the subsequent stage in accordance with the clock signal SCK. In  FIG. 8 , a first stage, a second stage, . . . , an m-th stage are written in order from upstream of supply of the printing data signal SI in order to distinguish the shift registers  222 . 
     Each of m latch circuits  224  latches the 2-bit printing data [SIH, SIL] held in each of m shift registers  222  at a rise of the latch signal LAT. 
     Each of m decoders  226  decodes the 2-bit printing data [SIH, SIL] latched by each of m latch circuits  224  and outputs selection signals Sa and Sb to the selection circuit  230  for each of the periods T 1  and T 2  defined by the latch signal LAT and the change signal CH. 
       FIG. 9  is a diagram illustrating a decoding content in the decoder  226 . For example, it is meant that when the latched 2-bit printing data [SIH, SIL] is [1, 0], the decoder  226  respectively outputs the logical levels of the selection signals Sa and Sb at H and L levels in the period  71  and L and H levels in the period T 2 . The logical levels of the selection signals Sa and Sb are shifted to a higher amplitude logical level based on the high voltage signal VHV than the logical levels of the clock signal SCK, the printing data signal SI, the latch signal LAT, and the change signal CH by a level shifter (not illustrated). 
     The selection circuit  230  is disposed in correspondence with each of the piezoelectric element  60  and the nozzle  651 . That is, the number of selection circuits  230  included in one drive signal selection circuit  120  is the same as the total number m of nozzles  651  included in the nozzle group  660 . 
       FIG. 10  is a diagram illustrating a configuration of the selection circuit  230  corresponding to one nozzle  651 . 
     As illustrated in  FIG. 10 , the selection circuit  230  includes inverters  232   a  and  232   b  that are NOT circuits, and transfer gates  234   a  and  234   b.    
     The selection signal Sa from the decoder  226  is supplied to a positive control terminal not denoted by a circle mark in the transfer gate  234   a  and is logically inverted by the inverter  232   a  and supplied to a negative control terminal denoted by a circle mark in the transfer gate  234   a . Similarly, the selection signal Sb is supplied to a positive control terminal of the transfer gate  234   b  and is logically inverted by the inverter  232   b  and supplied to a negative control terminal of the transfer gate  234   b.    
     The drive signal COMA is supplied to an input terminal of the transfer gate  234   a . The drive signal COMB is supplied to an input terminal of the transfer gate  234   b . Output terminals of the transfer gates  234   a  and  234   b  are coupled to each other in common. The drive signal VOUT is output to the ejecting unit  600  through the common coupling terminal. 
     In the transfer gate  234   a , the input terminal and output terminal are conducted (ON) when the selection signal Sa is at H level. The input terminal and the output terminal are not conducted (OFF) when the selection signal Sa is at L level. The same applies to the transfer gate  234   b . The ON or OFF state between the input terminal and the output terminal is set depending on the selection signal Sb. 
     Next, an operation of the drive signal selection circuit  120  will be described with reference to  FIG. 11 . 
     The printing data signal SI is serially supplied in synchronization with the clock signal SCK and is sequentially transferred in the shift register  222  corresponding to the nozzle. When the supply of the clock signal SCK is stopped, each shift register  222  is in a state where the 2-bit printing data [SIH, SIL] corresponding to the nozzle  651  is held in the shift register  222 . The printing data signal SI is supplied in order corresponding to the nozzles of the last m-th stage, the second stage, and the first stage in the shift registers  222 . 
     When the latch signal LAT rises, each latch circuit  224  latches the 2-bit printing data [SIH, SIL] held in the shift register  222  at the same time. In  FIG. 11 , LT 1 , LT 2 , . . . LTm denote the 2-bit printing data [SIH, SIL] latched by the latch circuits  224  corresponding to the first stage, the second stage, . . . , the m-th stage of the shift registers  222 . 
     The decoder  226  outputs the logical levels of the selection signals Sa and Sb in each of the periods T 1  and T 2  using the content illustrated in  FIG. 5  depending on the size of the dot defined in the latched 2-bit printing data [SIH, SIL]. 
     That is, when the printing data [SIH, SIL] is [1, 1] and defines the size of the large dot the decoder  226  sets the selection signals Sa and Sb at H and L levels in the period T 1  and H and L levels in the period T 2 . In addition, when the printing data [SIH, SIL] is [1, 0] and defines the size of the medium dot, the decoder  226  sets the selection signals Sa and Sb at H and L levels in the period T 1  and L and H levels in the period T 2 . In addition, when the printing data [SIH, SIL] is [0, 1] and defines the size of the small dot, the decoder  226  sets the selection signals Sa and Sb at L and L levels in the period T 1  and L and H levels in the period T 2 . In addition, when the printing data [SIH, SIL] is [0, 0] and defines no recording, the decoder  226  sets the selection signals Sa and Sb at L and H levels in the period T 1  and L and L levels in the period T 2 . 
     When the printing data [SIH, SIL] is [1, 1], the selection circuit  230  selects the trapezoidal waveform Adp 1  included in the drive signal COMA in the period T 1  since the selection signals Sa and Sb are at H and L levels. The selection circuit  230  selects the trapezoidal waveform Adp 2  included in the drive signal COMA in the period T 2  since Sa and Sb are at H and L levels. Consequently, the drive signal VOUT corresponding to “large dot” illustrated in  FIG. 7  is generated. 
     In addition, when the printing data [SIH, SIL] is [1, 0], the selection circuit  230  selects the trapezoidal waveform Adp 1  included in the drive signal COMA in the period T 1  since the selection signals Sa and Sb are at H and L levels. The selection circuit  230  selects the trapezoidal waveform Bdp 2  included in the drive signal COMB in the period T 2  since Sa and Sb are at L and H levels. Consequently, the drive signal VOUT corresponding to “medium dot” illustrated in  FIG. 7  is generated. 
     In addition, when the printing data [SIH, SIL] is [0, 1], the selection circuit  230  does not select any of the drive signals COMA and COMB in the period  71  since the selection signals Sa and Sb are at L and L levels. The selection circuit  230  selects the trapezoidal waveform Bdp 2  included in the drive signal COMB in the period T 2  since Sa and Sb are at L and H levels. Consequently, the drive signal VOUT corresponding to “small dot” illustrated in  FIG. 7  is generated. Since any of the drive signals COMA and COMB is not selected in the period T 1 , one end of the piezoelectric element  60  is open. However, the drive signal VOUT is held at the immediately previous voltage Vc by the capacitance of the piezoelectric element  60 . 
     In addition, when the printing data [SIH, SIL] is [0, 0], the selection circuit  230  selects the trapezoidal waveform Bdp 1  included in the drive signal COMB in the period T 1  since the selection signals Sa and Sb are at L and H levels. The selection circuit  230  does not select any of the drive signals COMA and COMB in the period T 2  since Sa and Sb are at L and L levels. Consequently, the drive signal VOUT corresponding to “no recording” illustrated in  FIG. 7  is generated. Since any of the drive signals COMA and COMB is not selected in the period T 2 , one end of the piezoelectric element  60  is open. However, the drive signal VOUT is held at the immediately previous voltage Vc by the capacitance of the piezoelectric element  60 . 
     1.6 Configuration of Drive Circuit 
     Next, a configuration and an operation of the drive circuit  50  generating and outputting the drive signals COMA and COMB will be described.  FIG. 12  is a diagram illustrating a circuit configuration of the drive circuit  50 . In the following description, digital data supplied to the drive circuit  50  will be described as the drive data COMA_D 0  and COMA_D 1 . Accordingly, a signal output by the drive circuit  50  will be described as the drive signal COMA, when the signal output by the drive circuit  50  is the drive signal COMB, the only difference is the supplied digital data that is the drive data COMB_D 0  and COMB_D 1 , and the configuration and the operation are the same. Accordingly, such a description will not be provided. 
     As illustrated in  FIG. 12 , the drive circuit  50  includes an integrated circuit device  500 , an output circuit  550 , a first feedback circuit  570 , and a second feedback circuit  572 . 
     The integrated circuit device  500  outputs gate signals for driving transistors M 1  and M 2  based on the 2-bit drive data COMA_D 0  and COMA_D 1  input through terminals In 1  and In 2 . The integrated circuit device  500  includes an accumulation unit  501 , a digital to analog converter (DAC)  511 , adders  512  and  513 , a comparator  514 , an inverter  515 , an integral attenuator  536 , an attenuator  517 , gate drivers  521  and  522 , and a reference voltage generation unit  580 . 
     The reference voltage generation unit  580  generates a first reference voltage DAC_HV as a high voltage side reference voltage and a second reference voltage DAC_LV as a low voltage side reference voltage and supplies the first reference voltage DAC_HV and the second reference voltage DAC_LV to the DAC  511 . 
     The accumulation unit  501  accumulates the 2-bit drive data COMA_D 0  and COMA__D 1  and supplies accumulated k-bit drive data dA defining the waveform of the drive signal COMA to the DAC  511 . 
     The DAC  511  converts the k-bit drive data dA into an original drive signal Aa having a voltage between the first reference voltage DAC_HV and the second reference voltage DAC_LV and supplies the original drive signal Aa to an input terminal (+) of the adder  512 . A signal acquired by amplifying the voltage of the original drive signal Aa is the drive signal COMA. That is, the original drive signal Aa is a target signal before amplification to the drive signal COMA. 
     The integral attenuator  516  attenuates and integrates a voltage of a terminal Out input through a terminal Vfb, that is, the drive signal COMA, and supplies the voltage to an input terminal (−) of the adder  512 . In obtaining of a deviation between the original drive signal Aa and the drive signal COMA, the integral attenuator  516  attenuates the voltage of the high voltage drive signal COMA with respect to the original drive signal Aa in order to match the amplitude ranges of both voltages. 
     The adder  512  supplies a signal Ab to an input terminal (+) of the adder  513 . The signal Ab has a voltage acquired by subtracting the voltage of the input terminal (−) from the voltage of the input terminal (+) and integrating the difference. 
     The attenuator  517  attenuates a high frequency component of the drive signal COMA input through a terminal Ifb and supplies the high frequency component to an input terminal (−) of the adder  513 . The function of the attenuator  517  is adjustment of a modulation gain. That is, the attenuator  517  adjusts the amount of change in the frequency or duty ratio of a modulation signal Ms that changes in accordance with the drive data dA. 
     The adder  513  supplies a signal As to the comparator  514 . The signal As has a voltage acquired by subtracting the voltage of the input terminal (−) from the voltage of the input terminal (+). The voltage of the signal As output from the adder  513  is a signal in which a deviation acquired by subtracting the attenuated voltage of the drive signal COMA output from the terminal Out from the voltage of the original drive signal Aa of a target is corrected using the high frequency component of the drive signal COMA. 
     The comparator  514  outputs the modulation signal Ms acquired by performing pulse modulation based on the voltage subtracted by the adder  513 . The comparator  514  outputs the modulation signal Ms that is set to be at H level at the time of increase in the voltage of the signal As output from the adder  513  when the signal As becomes greater than or equal to a voltage threshold Vth 1 , and that is set to be at L level at the time of decrease in the voltage of the signal As when the signal Ac becomes lees than a voltage threshold Vth 2 . The voltage thresholds are set to be in a relationship of Vth 1 &gt;Vth 2 . 
     The modulation signal Ms acquired by pulse modulation by the comparator  514  is supplied to the gate driver  521 . In addition, the modulation signal Ms is supplied to the gate driver  522  through logical inversion by the inverter  515 . Thus, signals having logical levels exclusive with each other are supplied to the gate driver  521  and the gate driver  522 . The exclusive signals may be signals of which the timings are controlled such that the logical levels of the signals supplied to the gate driver  521  and the gate driver  522  are not at H level at the same time. That is, a meaning of control such that the transistor M 1  and the transistor M 2  are not ON at the same time is included. 
     The adder  512 , the adder  513 , the comparator  514 , the inverter  515 , the integral attenuator  516 , and the attenuator  517  function as a modulation unit  510  that generates the modulation signal Ms by modulating the original drive signal Aa. 
     The gate driver  521  shifts the level of the voltage value of the modulation signal Ms output from the comparator  514  and outputs the modulation signal Ms from a terminal Hdr. Specifically, a voltage is supplied through a terminal Bst on a high potential side of the power supply voltage of the gate driver  521 , and a voltage is supplied through a terminal Sw on a low potential side of the power supply voltage of the gate driver  521 . The terminal Bst is coupled in common to one end of a capacitor C 5  disposed outside the integrated circuit device  500  and a cathode terminal of a diode D 1  for preventing a reverse current. In addition, another end of the capacitor C 5  is coupled to the terminal Sw. In addition, an anode terminal of the diode D 1  is coupled to a terminal Gvd to which a voltage Vm of the power supply voltage signal GVDD supplied from the voltage conversion circuit  114  illustrated in  FIG. 4  is supplied. Accordingly, a difference in potential between the terminal Bst and the terminal Sw is approximately equal to a difference in potential between both ends of the capacitor C 5 , that is, the voltage Vm. The gate driver  521  generates a signal having a voltage value greater by the voltage Vm than that of the terminal Sw in accordance with the input modulation signal Ms and outputs the signal from the terminal Hdr. 
     The gate driver  522  operates on a lower potential side than the gate driver  521 . The gate driver  522  shifts the level of the voltage value of a signal acquired by inverting the modulation signal Ms output from the comparator  514  by the inverter  515 , and outputs the signal from a terminal Ldr. Specifically, the voltage Vm is supplied to a high potential side of the power supply voltage of the gate driver  522 , and the ground potential is supplied to a low potential side of the power supply voltage of the gate driver  522 . The gate driver  522  generates a signal having a voltage value greater by the voltage Vm than that of a terminal Gnd in accordance with the input inverted signal of the modulation signal Ms and outputs the signal from the terminal Ldr. 
     The output circuit  550  includes the transistors M 1  and M 2 , resistors R 1  and R 2 , and a low pass filter circuit (low pass filter)  560 . For example, each of the transistors M 1  and M 2  is an N channel type field effect transistor (FET). 
     A voltage Vh of the high voltage signal VHV is supplied to a drain electrode of the transistor M 1 . In addition, a gate electrode of the transistor M 1  is coupled to one end of the resistor R 1 , and another end of the. resistor R 1  is coupled to the terminal Hdr. In addition, a source electrode of the transistor M 1  is coupled to the terminal Sw. The transistor M 1  coupled as described above operates depending on the output signal of the gate driver  521  output from the terminal Hdr. 
     A drain electrode of the transistor M 2  is coupled to the source electrode of the transistor M 1 . In addition, a gate electrode of the transistor M 2  is coupled to one end of the resistor R 2 , and another end of the resistor R 2  is coupled to the terminal Ldr. In addition, the ground potential is supplied to a source electrode of the transistor M 2 . The transistor M 2  coupled as described above operates depending on the output signal of the gate driver  522  output from the terminal Ldr. 
     When the transistor M 1  is controlled to be OFF, and the transistor M 2  is controlled to be ON, the coupling point to which the terminal Sw is coupled has the ground potential, and the voltage Vm is supplied to the terminal Bst. When the transistor M 1  is controlled to be ON, and the transistor M 2  is controlled to be OFF, the voltage Vh is supplied to the coupling point to which the terminal Sw is coupled. Thus, the terminal Bst is supplied with the voltage Vh+voltage Vm. 
     That is, the gate driver  521  driving the transistor M 1  supplies a signal having the voltage Vh as L level and the voltage Vh+voltage Vm as H level to the gate electrode of the transistor M 1  due to a change in the voltage of the terminal Sw to the ground potential or the voltage Vh depending on the operations of the transistors M 1  and M 2  with the capacitor C 5  as a floating power supply. The transistor M 1  performs a switching operation based on the signal supplied to the gate electrode. In addition, the gate driver  522  driving the transistor M 2  supplies a signal having the ground potential as L level and the voltage Vm as H level to the gate electrode of the transistor M 2  regardless of the operations of the transistors M 1  and M 2 . The transistor M 2  performs a switching operation based on the signal supplied to the gate electrode. Accordingly, an amplified modulation signal acquired by amplifying the modulation signal Ms based on the voltage Vh is generated at the coupling point between the source electrode of the transistor M 1  and the drain electrode of the transistor M 2 . 
     The low pass filter circuit  560  includes an inductor L 1  and a capacitor C 1 . 
     One end of the inductor L 1  is coupled in common to the source electrode of the transistor M 1  and the drain electrode of the transistor M 2 . In addition, another end of the inductor L 1  is coupled in common to the terminal Out from which the drive signal COMA is output, and one end of the capacitor C 1 . The ground potential is supplied to another end of the capacitor C 1 . 
     The inductor L 1  and the capacitor C 1  coupled as described above smooth the amplified modulation signal supplied to the coupling point between the transistors M 1  and M 2 . Accordingly, the amplified modulation signal is demodulated, and the drive signal COMA is generated. The generated drive signal COMA is output from the terminal Out. 
     In addition, the drive circuit  50  includes the first feedback circuit  570  and the second feedback circuit  572  for increasing the frequency of self-exciting oscillation such that the accuracy of the drive signal COMA can be sufficiently secured. 
     The first feedback circuit  570  includes resistors R 3  and R 4 . One end of the resistor R 3  is coupled to the terminal Out. In addition, another end of the resistor R 3  is coupled in common to the terminal Vfb and one end of the resistor R 4 . The voltage Vh is supplied to another end of the resistor R 4 . Accordingly, the drive signal COMA passing through the first feedback circuit  570  from the terminal Out is pulled up and fed back to the terminal Vfb. 
     The second feedback circuit  572  includes resistors R 5  and R 6  and capacitors C 2 , C 3 , and C 4 . One end of the capacitor C 2  is coupled to the terminal Out. In addition, another end of the capacitor C 2  is coupled in common to one end of the resistor R 5  and one end of the resistor R 6 . The ground potential is supplied to another end of the resistor R 5 . Accordingly, the capacitor C 2  and the resistor R 5  function as a high pass filter. In addition, another end of the resistor R 6  is coupled in common to one end of the capacitor C 3  and one end of the capacitor C 4 . The ground potential is supplied to another end of the capacitor C 3 . Accordingly, the resistor R 6  and the capacitor C 3  function as a low pass filter. The second feedback circuit  572  functions as a band pass filter that passes a predetermined frequency range of the drive signal COMA. Another end of the capacitor C 4  is coupled to the terminal Ifb. Accordingly, a direct current component in the high frequency component of the drive signal COMA passing through the second feedback circuit  572  is cut and fed back to the terminal Ifb. 
     1.7 Configuration and Coupling of Cable 
     A configuration of the cable  19  electrically coupling the control substrate  100 , the drive circuit substrate  101 , and the head substrate  104  to each other will be described using  FIG. 13 .  FIG. 13  is a diagram illustrating a configuration of the cable  19 . The cable  19  has an approximately rectangular shape having short edges  191  and  192  facing each other and long edges  193  and  194  facing each other. For example, the cable  19  is a flexible flat cable (FFC). 
     On the short edge  191  side of the cable  19 , a plurality of terminals  195  are linearly disposed from the long edge  193  side toward the long edge  194  side along the short edge  191 . Specifically, n terminals  195 - 1  to  195 - n  are linearly disposed from the long edge  193  side toward the long edge  194  side along the short edge  191 . In addition, on the short edge  192  side of the cable  19 , a plurality of terminals  196  are linearly disposed from the long edge  193  side toward the long edge  194  side along the short edge  192 . Specifically, n terminals  196 - 1  to  196 - n  are linearly disposed from the long edge  193  side toward the long edge  194  side along the short edge  192 . In addition, in the cable  19 , a plurality of wires  197  that electrically couple the plurality of terminals  195  to the plurality of terminals  196  respectively are linearly disposed from the long edge  193  side toward the long edge  194  side. Specifically, a wire  197 - i  (i is any of 1 to n) electrically couples a terminal  195 - i  to a terminal  196 - i . In the cable  19  configured as described above, for example, various signals input from the terminal  195 - i  are propagated by being output from the terminal  196 - i  through the wire  197 - i . The configuration of the cable  19  illustrated in  FIG. 13  is one example and is not for limitation purposes. For example, the plurality of terminals  195  and the plurality of terminals  196  may be disposed on different surfaces of the cable  19  or may be disposed on both of the surface and the rear surface. 
     Next, a coupling relationship among the control substrate  100 , the drive circuit substrate  101 , the head substrate  104 , and the plurality of cables  19  will be described using  FIG. 14 .  FIG. 14  is a diagram illustrating the coupling relationship among the control substrate  100 , the drive circuit substrate  101 , the head substrate  104 , and the plurality of cable  19 . FIC.  11  conceptually illustrates the coupling relationship among the control substrate  100 , the drive circuit substrate  101 , the head substrate  104 , and the plurality of cables  19 . The control substrate  100 , the drive circuit substrate  101 , the head substrate  104 , and the plurality of cables  19  are not limited to the arrangement illustrated in  FIG. 14 . 
     In the following description, the plurality of cables  19  will be respectively referred to as cables  19   a ,  19   b ,  19   c , and  19   d  in order to distinguish each of plurality of cables  19 . The plurality of terminals  195  and  196  included in the cable  19   a  will be respectively referred to as terminals  195   a  and  196   a , and the plurality of wires  197  included in the cable  19   a  will be referred to as wires  197   a . Similarly, the plurality of terminals  195  and  196  included in the cable  19   b  will be respectively referred to as terminals  195   b  and  196   b , and the plurality of wires  197  included in the cable  19   b  will be referred to as wires  197   b . Similarly, the plurality of terminals  195  and  196  included in the cable  19   c  will be respectively referred to as terminals  195   c  and  196   c , and the plurality of wires  197  included in the cable  19   c  will be referred to as wires  197   c . Similarly, the plurality of terminals  195  and  196  included in the cable  19   d  will be respectively referred to as terminals  195   d  and  196   d , and the plurality of wires  197  included in the cable  19   d  will be referred to wires  197   d.    
     In addition, while illustration and description are not provided, for example, each of the plurality of terminals  195  and  196  of the cable  19  may be electrically coupled to the control substrate  100 , the drive circuit substrate  101 , and the head substrate  104  through a connector. In addition, each of the plurality of terminals  195  and  196  of the cable  19  may be electrically coupled to the control substrate  100 , the drive circuit substrate  101 , and the head substrate  104  through solder or the like. 
     As illustrated in  FIG. 14 , the cable  19   a  electrically couples the control substrate  100  to the head substrate  104 . The cable  19   a  propagates the differential signals [SI 1 +, SI 1 −] to [SI 6 +, SI 6 −], [LAT+, LAT−], [CH+, CH−], and [SCK+, SCK−] illustrated in  FIG. 3  to the head substrate  104  from the control substrate  100 . Specifically, by electrically coupling the plurality of terminals  195   a  included in the cable  19   a  to the control substrate  100 , each of the differential signals [SI 1 +, SI 1 −] to [SI 6 +, SI 6 −], [LAT+, LAT−], [CH+, CH−], and [SCK+, SCK−] generated in various configurations mounted on the control substrate  100  is input into the cable  19   a . The differential signals are propagated through the plurality of wires  197   a  and then, are output to the head substrate  104  from the plurality of terminals  196   a.    
     In addition, the cable  19   b  electrically couples the control substrate  100  to the drive circuit substrate  101 . The cable  19   b  propagates the drive data COMA_D 0 , COMA_D 1 , COMB_D 0 , and COMB_D 1 , the high voltage signal VHV, and the ground voltage signal GND illustrated in  FIG. 3  to the drive circuit substrate  101  from the control substrate  100 . Specifically, by electrically coupling the plurality of terminals  195   b  included in the cable  19   b  to the control substrate  100 , each of the drive data COMA_D 0 , COMA_D 1 , COMB_D 0 , and COMB_D 1 , the high voltage signal VHV, and the ground voltage signal GND generated in various configurations mounted on the control substrate  100  is input into the cable  19   b . The signals are propagated through the plurality of wires  197   b  and then, are output to the head substrate  104  from the plurality of terminals  196   b.    
     In addition, the cables  19   c  and  19   a  electrically couple the drive circuit substrate  101  to the head substrate  104 . The cables  19   c  and  19   d  propagate the drive signals COMA 1  to COMA 6  and COMB 1  to COMB 6 , the reference voltage signals VBS 1  to VBS 6 , the high voltage signal VHV, the low voltage signal VDD, and the ground voltage signal GND to the head substrate  104  from the drive circuit substrate  101  illustrated in  FIG. 3 . Specifically, by electrically coupling each of the plurality of terminals  195   c  and  195   d  respectively included in the cables  19   c  and  19   d  to the drive circuit substrate  101  and electrically coupling each of the plurality of terminals  196   c  and  196   d  to the head substrate  104 , each of the drive signals COMA 1  to COMA 6  and COMB 1  to COMB 6 , the reference voltage signals VBS 1  to VBS 6 , the high voltage signal VHV, the low voltage signal VDD, and the ground voltage signal GND generated in various configurations mounted on the drive circuit substrate  101  is input into the cables  19   c  and  19   d . The signals are propagated through the plurality of wires  197   c  and  197   d  and then, are output to the head substrate  104  from the plurality of terminals  196   c  and  196   d.    
     Among the plurality of cables  19  coupled as described above, the cables  19   c  and  19   d  transferring the drive signals COMA and COMB cause a distortion in the signal waveforms of the drive signals COMA and COMB due to inductance components of the cables  19   c  and  19   d . Consequently, when the drive signals COMA and COMB are supplied to the head substrate  104 , an overshoot may occur in the signal waveforms of the drive signals COMA and COMB. Such an overshoot may instantaneously apply a voltage outside a voltage range of guaranteed operation to the drive signal selection circuit  120  or the piezoelectric element  60 . The voltage outside the voltage range of guaranteed operation may cause the drive signal selection circuit  120  or the piezoelectric element  60  to erroneously operate. 
     Particularly, in a large format printer such as the liquid ejecting apparatus  1  illustrated in the first embodiment, the movable range R of the head unit  20  is increased. The wire lengths of the cables  19   c  and  19   d  propagating the drive signals COMA and COMB are greater than or equal to 1 m. The inductance components caused by the cables  19   c  and  19   d  are increased. Thus, the possibility of causing an overshoot in the drive signals COMA and COMB when the drive signals COMA and COMB are supplied to the head substrate  104  is increased. 
     In addition, when the amount of current flowing through the cables  19   c  and  19   d  due to the drive signals COMA and COMB is increased, the maximum voltage of the overshoot may be increased. That is, when the drive signals coma and COMB are supplied to the nozzle group  660  in which 600 or more of a large number of nozzles are disposed at a density of 300 or more per inch as illustrated in the first embodiment, the maximum voltage of the overshoot may be increased. 
     In addition, in the liquid ejecting apparatus  1  illustrated in the first embodiment, one drive circuit  50   a  supplies the drive signal COMA to six nozzle groups  660 , and one drive circuit  50   b  supplies the drive signal COMB to six nozzle groups  660 . Accordingly, the amount of current output from the drive circuits  50   a  and  50   b  due to the drive signals COMA and COMB is increased. For example, the effect of the inductor L 1  illustrated in  FIG. 12  is increased, and the overshoot may be promoted. 
     Furthermore, when the drive signals COMA and COMB are transferred through an FFC or the like including a plurality of wires, mutual inductance occurs among the plurality of wires through which the drive signals COMA and COMB are propagated. The mutual inductance is changed by the magnitudes and directions of the signals propagated through wires disposed in parallel. That is, the magnitude of the mutual inductance may vary for each of the plurality of wires through which the drive signals COMA and COMB are propagated. Thus, when a plurality of drive signals COMA and COMB are propagated through different wires of the same cable, variations occur in the voltage value of the overshoot caused by the wires of propagation. A sufficient margin in which the variations are considered needs to be secured in the drive signal selection circuit  120  or the piezoelectric element  60 , and the signal waveforms of the drive signals COMA and COMB are constrained. 
     Configurations of the cables  19   c  and  19   d  for reducing the overshoot occurring in the drive signals COMA and COMB will be described using  FIG. 15  to  FIG. 17 . As illustrated in  FIG. 15  to  FIG. 17 , the cables  19   c  and  19   d  in the first embodiment include 14 terminals  195 , 14 terminals  196 , and 14 wires  197 . 
     Specifically, the cable  19   c  includes a terminal  196   c - 2  from which the drive signal COMA 1  in the drive signal VOUT 1  input into one end of the piezoelectric element  60  included in the first nozzle group  660   a  from the drive circuit  50   a  is output, a terminal  196   c - 3  from which the reference voltage signal VBS 1  input into the other end of the piezoelectric element  60  is output, and a terminal  196   c - 4  from which the drive signal COMB 2  in the drive signal VOUT 2  input into one end of the piezoelectric element  60  included in the second nozzle group  660   b  from the drive circuit  50   b  is output. 
     In addition, the cable  19   d  includes a terminal  196   d - 5  from which the drive signal COMA 2  in the drive signal VOUT 2  input into one end of the piezoelectric element  60  included in the second nozzle group  660   b  from the drive circuit  50   a  is output, a terminal  196   d - 4  from which the reference voltage signal VBS 2  input into the other end of the piezoelectric element  60  is output, and a terminal  196   d - 3  from which the drive signal COMB 1  in the drive signal VOUT 1  input into one end of the piezoelectric element  60  included in the first nozzle group  660   a  from the drive circuit  50   a  is output. 
     The cable  19   c  and the cable  19   d  are disposed to at least partially overlap with each other in a direction orthogonal to a direction in which the terminal  196   c - 2  and the terminal  196   c - 3  of the cable  19   c  are lined up. 
     In the cable  19   c  and the cable  19   d  disposed to at least partially overlap with each other, the terminal  196   c - 3  and the terminal  196   d - 4  are disposed between the terminal  196   c - 2  and the terminal  196   d - 5 . 
     In addition, the terminal  196   c - 3  is disposed between the terminal  196   c - 2  and the terminal  196   c - 4 . The terminal  196   d - 4  is disposed between the terminal  196   d - 5  and the terminal  196   d - 3 . The cable  19   c  and the cable  19   d  are disposed such that the terminal  196   c - 3  and the terminal  196   d - 3  at least partially overlap with each other, and the terminal  196   d - 4  and the terminal  196   c - 4  at least partially overlap with each other. 
     Details will be described using the drawings. First, a specific example of signals propagated through each of the terminals  195  and  196  and the wire  197  of the cable  19   c  and the cable  19   d  will be described using  FIG. 15  and  FIG. 16 .  FIG. 1S  is a diagram illustrating a specific example of a signal propagated through the cable  19   c . In addition,  FIG. 16  is a diagram illustrating a specific example of a signal propagated through the cable  19   d.    
     As illustrated in  FIG. 15 , the plurality of drive signals COMA and COMB, the plurality of reference voltage signals VBS, the low voltage signal VDD, and the ground voltage signal GND are propagated through the cable  19   c.    
     Specifically, the ground voltage signal GND is input into a terminal  195   c - 1 . The ground voltage signal GND is propagated through a wire  197   c - 1  and is output from a terminal  196   c - 1 . 
     In addition, the drive signal COMA 1  is input into a terminal  195   c - 2 . The drive signal COMA 1  is propagated through a wire  197   c - 2  and is output from the terminal  196   c - 2 . The reference voltage signal VBS 1  is input into a terminal  195   c - 3 . The reference voltage signal VBS 1  is propagated through a wire  197   c - 3  and is output from a terminal  196   c - 3 . That is, the drive signal COMA 1  and the reference voltage signal VBS 1  supplied to the piezoelectric element  60  included in the first nozzle group  660   a  are propagated through the wire  197   c - 2  and the wire  197   c - 3 . 
     In addition., the drive signal COMB 2  is input into a terminal  195   c - 4 . The drive signal COMB 2  is propagated through a wire  197   c - 4  and is output from the terminal  196   c - 4  The reference voltage signal VBS 2  is input into a terminal  195   c - 5 . The reference voltage signal VBS 2  is propagated through a wire  197   c -S and is output from a terminal  196   c - 5 . That is, the drive signal COMB 2  and the reference voltage signal VBS 2  supplied to the piezoelectric element  60  included in the second nozzle group  660   b  are propagated through the wire  197   c - 4  and the wire  197   c - 5 . 
     In addition, the drive signal COMA 3  is input into a terminal  195   c - 6 . The drive signal COMA 3  is propagated through a wire  197   c - 6  and is output from the terminal  196   c - 6  The reference voltage signal VBS 3  is input into a terminal  195   c - 7 . The reference voltage signal VBS 3  is propagated through a wire  197   c - 7  and is output from a terminal  196   c - 7 . That is, the drive signal COMA 3  and the reference voltage signal VBS 3  supplied to the piezoelectric element  60  included in the third nozzle group  660   c  are propagated through the wire  197   c - 6  and the wire  197   c - 7 . 
     In addition, the drive signal COMB 4  is input into a terminal  195   c - 8 . The drive signal COMB 4  is propagated through a wire  197   c - 8  and is output from a terminal  196   c - 8 . The reference voltage signal VBS 4  is input into a terminal  195   c - 9 . The reference voltage signal VBS 4  is propagated through a wire  197   c - 9  and is output from a terminal  196   c - 9 . That is, the drive signal COMB 4  and the reference voltage signal VBS 4  supplied to the piezoelectric element  60  included in the fourth nozzle group  660   a  are propagated through the wire  197   c - 8  and the wire  197   c - 9 . 
     In addition, the drive signal COMA 5  is input into a terminal  195   c - 10 . The drive signal COMA 5  is propagated through a wire  197   c - 10  and is output from a terminal  196   c - 10  The reference voltage signal VBS 5  is input into a terminal  195   c - 11 . The reference voltage signal VBS 5  is propagated through a wire  197   c - 11  and is output from a terminal  196   c - 11  That is, the drive signal COMA 5  and the reference voltage signal VBS 5  supplied to the piezoelectric element  60  included in the fifth nozzle group  660   e  are propagated through the wire  197   c - 10  and the wire  197   c - 1 . 
     In addition, the drive signal COMB 6  is input into a terminal  195   c - 12 . The drive signal COMB 6  is propagated through a wire  197   c - 12  and is output from a terminal  196   c - 12  The reference voltage signal VBS 6  is input into a terminal  195   c - 13 . The reference voltage signal VBS 6  is propagated through a wire  197   c - 13  and is output from a terminal  196   c - 13  That is, the drive signal COMB 6  and the reference voltage signal VBS 6  supplied to the piezoelectric element  60  included in the sixth nozzle group  660   f  are propagated through the wire  197   c - 12  and the wire  197   c - 13 . 
     In addition, the low voltage signal VDD is input into a terminal  195   c - 14 . The low voltage signal VDD is propagated through a wire  197   c - 14  and is output from a terminal  196   c - 14 . 
     As described above, in the cable  19   c , the drive signal COMA or the drive signal COMB and the reference voltage signal VBS supplied for each of the plurality of nozzle groups  660  disposed in the ejecting head  21  are closely positioned. Furthermore, the supplied drive signal COMA and the drive signal COMB are alternately provided for each of the adjacent nozzle groups. The cable  19   c  is one example of a first cable. The terminal  196   c - 2  included in the cable  19   c  is one example of a first terminal. The terminal  196   c - 3  is one example of a second terminal. The terminal  196   c - 4  is one example of a fifth terminal. 
     As illustrated in  FIG. 16 , the plurality of drive signals COMA and COMB, the plurality of reference voltage signals VBS, the high voltage signal VHV, and the ground voltage signal GND are propagated through the cable  19   d.    
     Specifically, the high voltage signal VHV is input into a terminal  195   d - 1 . The high voltage signal VHV is propagated through a wire  197   d - 1  and is output from a terminal  196   d - 1 . 
     In addition, the reference voltage signal VBS 1  is input into a terminal  195   d - 2 . The reference voltage signal VBS 1  is propagated through a wire  197   d - 2  and is output from the terminal  196   d - 2 . The drive signal COMB 1  is input into a terminal  195   d - 3 . The drive signal COMB 1  is propagated through a wire  197   d - 3  and is output from the terminal  196   d - 3  That is, the drive signal COMB 1  and the reference voltage signal VBS 1  supplied to the piezoelectric element  60  included in the first nozzle group  660   a  are propagated through the wire  197   d - 2  and the wire  197   d - 3 . 
     In addition, the reference voltage signal VBS 2  is input into a terminal  195   d - 4 . The reference voltage signal VBS 2  is propagated through a wire  197   d - 4  and is output from the terminal  196   d - 4 . The drive signal COMA 2  is input into a terminal  195   d - 5 . The drive signal COMA 2  is propagated through a wire  197   d - 5  and is output from the terminal  196   d - 5  That is, the drive signal COMA 2  and the reference voltage signal VBS 2  supplied to the piezoelectric element  60  included in the second nozzle group  660   b  are propagated through the wire  197   d - 4  and the wire  197   d - 5 . 
     In addition, the reference voltage signal VBS 3  is input into a terminal  195   d - 6 . The reference voltage signal VBS 3  is propagated through a wire  197   d - 6  and is output from a terminal  196   d - 6 . The drive signal COMB 3  is input into a terminal  195   d - 7 . The drive signal COMB 3  is propagated through a wire  197   d - 7  and is output from the terminal  196   d - 7  That is, the drive signal COMB 3  and the reference voltage signal VBS 3  supplied to the piezoelectric element  60  included in the third nozzle group  660   c  are propagated through the wire  197   d - 6  and the wire  197   d - 7 . 
     In addition, the reference voltage signal VBS 4  is input into a terminal  195   d - 8 . The reference voltage signal VBS 4  is propagated through a wire  197   d - 3  and is output from a terminal  196   d - 8 . The drive signal COMA 4  is input into a terminal  195   d - 9 . The drive signal COMA 4  is propagated through a wire  197   d - 9  and is output from a terminal  196   d - 9 . That is, the drive signal COMA 4  and the reference voltage signal VBS 4  supplied to the piezoelectric element  60  included in the fourth nozzle group  660   d  are propagated through the wire  197   d - 8  and the wire  197   d - 9 . 
     In addition, the reference voltage signal VBS 5  is input into a terminal  195   d - 30 . The reference voltage signal VBS 5  is propagated through a wire  197   d - 10  and is output from a terminal  196   d - 10 . The drive signal COMB 5  is input into a terminal  195   d - 11 . The drive signal COMB 5  is propagated through a wire  197   d - 11  and is output from a terminal  196   d - 11 . That is, the drive signal COMBS and the reference voltage signal VBS 5  supplied to the piezoelectric element  60  included in the fifth nozzle group  660   e  are propagated through the wire  197   d - 10  and the wire  197   d - 11 . 
     In addition, the reference voltage signal VBS 6  is input into a terminal  195   d - 12 . The reference voltage signal VBS 6  is propagated through a wire  197   d - 12  and is output from a terminal  196   d - 12 . The drive signal COMA 6  is input into a terminal  195   d - 13 . The drive signal COMA 6  is propagated through a wire  197   d - 13  and is output from a terminal  196   a - 13 . That is, the drive signal COMA 6  and the reference voltage signal VBS 6  supplied to the piezoelectric element  60  included in the sixth nozzle group  660   f  are propagated through the wire  197   d - 12  and the wire  197   d - 13 . 
     In addition, the ground voltage signal GND is input into a terminal  195   a - 14 . The ground voltage signal GND is propagated through a wire  197   d - 14  and is output from a terminal  196   d - 14 . 
     As described above, in the cable  19   d , the drive signal COMA or the drive signal COMB and the reference voltage signal VBS supplied for each of the plurality of nozzle groups  660  disposed in the ejecting head  21  are closely positioned. Furthermore, the supplied drive signal COMA and the drive signal COMB are alternately provided for each of the adjacent nozzle groups. The cable  19   d  is one example of a second cable. The terminal  196   d - 5  included in the cable  19   d  is one example of a third terminal. The terminal  196   d - 4  is one example of a fourth terminal. The terminal  196   d - 3  is one example of a sixth terminal. 
     The propagated signals illustrated in  FIG. 15  and  FIG. 16  are merely for illustrative purposes and not for limitation purposes. For example, the signal propagated through the cable  19   c  may be replaced with the signal propagated through the cable  19   d.    
       FIG. 17  is a diagram for describing mutual arrangement of the cables  19   c  and  19   d . In  FIG. 17 , the side of the terminals  196   c  and  196   d  on which the cables  19   c  and  19   d  are electrically coupled to the head substrate  104  is illustrated. In addition, directions x 1 , y 1 , and z 1  that are orthogonal to each ether are illustrated in  FIG. 17 . 
     As illustrated in  FIG. 17 , the terminals  196   c - 1  to  196   c - 14  in the end portion of the cable  19   c  are linearly disposed in the direction x 1 . The wires  197   c - 1  to  197   c - 14  (refer to  FIG. 13 ) respectively corresponding to the terminals  196   c - 1  to  196   c - 14  are disposed in the direction y 1 . In addition, the terminals  196   d - 1  to  196   d - 14  in the end portion of the cable  19   d  are linearly disposed in the direction x 1 . The wires  197   d - 1  to  197   d - 14  (refer to  FIG. 13 ) respectively corresponding to the terminals  196   d - 1  to  195   d - 14  are disposed in the direction y 1 . 
     The cable  19   c  and the cable  19   d  are disposed in an overlapping manner in the direction z 1  orthogonal to the direction x 1  in which the terminals  196   c - 1  to  196   c - 14  are lined up. In other words, the cable  19   c  and the cable  19   d  are disposed in an overlapping manner in a plan view. Specifically, a terminal  196   c - j  (j is any of 1 to 14) of the cable  19   c  and a terminal  196   d - j  of the cable  19   d  are disposed in an overlapping manner in a plan view. 
     The cable  19   c  and the cable  19   d  are disposed in an overlapping manner in a plan view, and the terminal  196   c - j  (j is any of 1 to 14) and the terminal  196   d - j  are disposed in an overlapping manner in a plan view. Accordingly, a wire  197   c - j  electrically coupled to the terminal  196   c - j  and a wire  197   d - j  electrically coupled to the terminal  196   d - j  can be easily disposed in an overlapping manner. 
     1.8 Operation Effect 
     In the liquid ejecting apparatus  1  in the first embodiment described thus far, in the cable  19   c , the terminal  196   c - 2  from which the drive signal COMA 1  supplied to one end of the piezoelectric element  60  included in the first nozzle group  660   a  is output can be disposed close to the wire  197   c - 2  electrically coupled to the terminal  196   c - 2 . The terminal  196   c - 3  from which the reference voltage signal VBS 1  supplied to the other end of the piezoelectric element is output can be disposed close to the wire  197   c - 3  electrically coupled to the terminal  196   c - 3 . Currents in opposite directions flow in the wire  196   c - 2  and the wire  197   c - 3 . Thus, a magnetic field caused by currents caused by propagation of the drive signal COMA 1  through the wire  197   c - 2  and the wire  197   c - 3  is reduced, and an inductance component occurring in the wires can be reduced. 
     In addition, in the cable  19   d , the terminal  196   d - 5  from which the drive signal COMA 2  supplied to one end of the piezoelectric element  60  included in the second nozzle group  660   b  is output can be disposed close to the wire  197   d - 5  electrically coupled to the terminal  196   d - 5 . The terminal  196   d - 4  from which the reference voltage signal VBS 2  supplied to the other end of the piezoelectric element is output can be disposed close to the wire  197   d - 4  electrically coupled to the terminal  196   d - 4 . Currents in opposite directions flow in the wire  197   d - 4  and the wire  197   d - 5 . Thus, a magnetic field caused by currents caused by propagation of the drive signal COMA 2  through the wire  197   d - 4  and the wire  197   d - 5  is reduced, and an inductance component occurring in the wires can be reduced. 
     As described thus far, in the liquid ejecting apparatus  1  in the first embodiment, an inductance component occurring in the cables  19   c  and  19   d  can be reduced. Accordingly, an overshoot of the drive signal COMA caused by the inductance component can be reduced. 
     Furthermore, in the liquid ejecting apparatus  1  in the first embodiment, variations in mutual inductance occurring between the wires can be reduced.  FIG. 18  is a diagram for describing the effect of decrease in mutual inductance in the first embodiment. In the cable  19   c  illustrated in  FIG. 18 , a current I 1  caused by propagation of the drive signal COMA 1  flows in the order of the wire  197   c - 2 , the terminal  196   c - 2 , the piezoelectric element  60  included in the first nozzle group  660   a , the terminal  196   c - 3  and the wire  197   c - 3 . In the cable  19   d , a current  12  caused by propagation of the drive signal COMA 2  flows in the order of the wire  197   c - 2 , the terminal  196   c - 2 , the piezoelectric element  60  included in the first nozzle group  660   a , the terminal  196   c - 3 , and the wire  197   c - 3 . 
     In the liquid ejecting apparatus  1  in the first embodiment, in the cables  19   c  and  19   d , the terminal  196   c - 3  and the terminal  196   d - 4  disposed between the terminal  196   c - 2  and the terminal  196   d - 5 . Accordingly, the path of a current caused by propagation of the drive signal COMA 1  is in an opposite direction to the path of a current caused by propagation of the drive signal COMA 2 . That is, a magnetic flux ϕ 1  occurring in the path of a current caused by propagation of the drive signal COMA 1  is in an opposite direction to a magnetic flux ϕ 2  occurring in the path of a current caused by propagation of the drive signal COMA 2 . Accordingly, the effect of the magnetic flux on only any wire between different wires is reduced. Thus, variations in mutual inductance between wires through which the drive signal COMA is propagated can be reduced. Accordingly, the occurrence of a distortion in the waveform of the drive signal in the specific terminals  195  and  196  and the wire  197  due to the drive signals COMA and COMB propagated through the cables  19   c  and  19   d  can be reduced. 
     Furthermore, since the magnetic flux occurring in the path of the current caused by propagation of the drive signal COMA 1  is in an opposite direction to the magnetic flux occurring in the path of the current caused by propagation of the drive signal COMA 2 , a change in the magnetic flux in each current path is promoted. That is, a change in magnetic flux caused in each current path is promoted. Due to the change in magnetic flux, a current flowing in the piezoelectric element  60  is rapidly decreased after the piezoelectric element  60  is charged. Therefore, an unnecessary current flowing into the piezoelectric element  60  is reduced, and an overshoot voltage applied to the piezoelectric element  60  can be reduced. 
     In addition, in the liquid ejecting apparatus  1  in the first embodiment, the terminal  196   d - 3  from which the drive signal COMB 1  supplied to the first nozzle group  660   a  and the terminal  196   c - 3  from which the reference voltage signal VBS 1  is output are disposed at overlapping positions in a plan view. Thus, the drive signal COMB 1  can achieve the same effect as the drive signal COMA 1 . Similarly, the terminal  196   c - 4  from which the drive signal COMB 2  supplied to the second nozzle group  660   b  and the terminal  196   d - 4  from which the reference voltage signal VBS 2  is output are disposed at overlapping positions in a plan view. Thus, the drive signal COMB 2  can achieve the same effect as the drive signal COMA 2 . 
     As described thus far, in the liquid ejecting apparatus  1  in the first embodiment, an overshoot occurring in the drive signals COMA and COMB can be reduced. Accordingly, even when the liquid ejecting apparatus  1  is a large format printer having the possibility of increase in the wire lengths of the cables  19   c  and  19   d  or includes  600  or more of a large number of nozzles in the ejecting head  21  an overshoot occurring in the drive signals COMA and COMB can be reduced. 
     Furthermore, as illustrated in the first embodiment when the cable  19   c  and the cable  19   d  are disposed in an overlapping manner, ink mist floating inside the liquid ejecting apparatus  1  unevenly clings to any one of the cable  19   c  and the cable  19   d . When the ink mist clings to a terminal of the cable  19   c  or the cable  19   d , output currents of the drive circuits  50   a  and  50   b  outputting the drive signals COMA and COMB are increased, and heat emission of the drive circuits  50   a  and  50   b  are increased. 
     In the first embodiment, the drive signals COMA and COMB are alternately provided in both of the cables  19   c  and  19   d . Accordingly, even when ink mist unevenly clings to any one of the cables  19   c  and  19   d , an increase in the output current of only one of the drive circuits  50   a  and  50   b  can be reduced. Thus, an effect such that an increase in heat emission of the drive circuits  50   a  and  50   b  can be reduced is also accomplished. 
     2. Second Embodiment 
     Next, the liquid ejecting apparatus  1  in a second embodiment will be described using  FIG. 19  to  FIG. 21 . The liquid ejecting apparatus  1  of the second embodiment is different from the first embodiment in that the cable  19  coupling the drive circuit substrate  101  to the head substrate  104  is electrically coupled by one cable  19   e . In description of the liquid ejecting apparatus  1  of the second embodiment, the same configuration as the first embodiment will be designated by the same reference sign, and a description of such a configuration will not be repeated. 
     In the liquid ejecting apparatus  1  of the second embodiment, the cable  19   e  includes a terminal  196   e - 2  from which the drive signal COMA 1  input into one end of the piezoelectric element  60  included in the first nozzle group  660   a  from the drive circuit  50   a  is output, a terminal  196   e - 3  from which the reference voltage signal VBS 1  input into the other end of the piezoelectric element  60  is output, a terminal  196   e - 19  from which the drive signal COMA 2  input into one end of the piezoelectric element  60  included in the second nozzle group  660   b  from the drive circuit  50   a  is output, a terminal  196   e - 18  from which the reference voltage signal VBS 2  input into the other end of the piezoelectric element  60  is output, a terminal  196   e - 4  from which the drive signal COMB 2  input into one end of the piezoelectric element  60  included in the second nozzle group  660   b  from the drive circuit  50   b  is output, and a terminal  196   e - 17  from which the drive signal COMB 1  input into one end of the piezoelectric element  60  included in the first nozzle group  660   a  from the drive circuit  50   b  is output. 
     in the cable  19   e , the terminal  196   e - 3  and the terminal  196   e - 18  are disposed between the terminal  196   e - 2  and the terminal  196   e - 19 . In a direction orthogonal to a direction in which the terminal  196   e - 2  and the terminal  196   e - 3  are lined up, the terminal  196   e - 3  and the terminal  196   e - 17  are disposed to at least partially overlap with each other, and the terminal  196   e - 18  and the terminal  196   e - 4  are disposed to at least partially overlap with each other. 
     Details will be described using the drawings.  FIG. 19  is a diagram illustrating a state where the cable  19   e  is applied. As illustrated in  FIG. 19 , the cable  19   e  includes  28  terminals  195   e ,  28  terminals  196   e , and  28  wires  197 . In addition, a cut portion  198  is disposed between a terminal  195   e - 14  and a terminal  195   e - 28  of the cable  19   e . A cut portion  199  is disposed between a terminal  196   e - 14  and a terminal  196   e - 28 . The cable  19   e  is configured by folding the cable  19   e  once or a plurality of times such that terminals  196   e - 1  to  196   e - 14  at least partially overlap with terminals  196   e - 15  to  196   e - 28 . 
     The same signals as the terminals  195   c - 1  to  195   c - 14 , the terminals  196   c - 1  to  196   c - 14 , and the wires  197   c - 1  to  197   c - 14  of the cable  19   c  in the first embodiment illustrated in  FIG. 16  are propagated through terminals  195   e -l to  195   e - 14 , the terminals  196   e - 1  to  196   e - 14 , and wires  197   e -l to  197   e - 14  of the cable  19   e  illustrated in  FIG. 19 , respectively. For example, the drive signal COMA 1  is propagated through the terminal  195   e - 2 , the terminal  196   e - 2 , and the wire  197   e - 2 . In addition, the reference voltage signal VBS 1  is propagated through the terminal  195   e - 3 , the terminal  196   e - 3 , and the wire  197   e - 3 . In addition, the drive signal COMB 2  is propagated through the terminal  195   e - 4 , the terminal  196   e - 4 , and the wire  197   e - 4 . 
     The same signals as the terminals  195   d - 1  to  196   d - 14 , the terminals  196   a - 1  to  196   d - 14 , and the wires  197   d - 1  to  197   a - 14  of the cable  19   d  in the first embodiment illustrated in  FIG. 17  are propagated through terminals  195   e - 15  to  195   e - 28 , the terminals  196   e - 15  to  196   e - 28 , and wires  197   e - 15  to  197   e - 28  of the cable  19   e , respectively. For example, the drive signal COMB 1  is propagated through the terminal  195   e - 17 , the terminal  196   e - 17 , and the wire  197   e - 17 . In addition, the reference voltage signal VBS 2  is propagated through the terminal  195   e - 18 , the terminal  196   e - 18 , and the wire  197   e - 18 . In addition, the drive signal COMA 2  is propagated through the terminal  195   e - 19 , the terminal  196   e - 19 , and the wire  197   e - 19 . 
     As described above, the cable  19   c  and the cable  19   d  of the first embodiment are configured with one cable as the cable  19   e . In the cable  19   e  of the liquid ejecting apparatus  1  illustrated in the second embodiment, the terminal  196   e - 2  is one example, of the first terminal. The terminal  196   e - 3  is one example of the second terminal. The terminal  196   e - 19  is one example of the third terminal. The terminal  196   e - 18  is one example of the fourth terminal. The terminal  196   e - 4  is one example of the fifth terminal. The terminal  196   e - 17  is one example of the sixth terminal. 
       FIG. 20  is a diagram illustrating one example of a state where the cable  19   e  is folded such that the terminals  196   e - 1  to  196   e - 14  at least partially overlap with the terminals  196   e - 15  to  196   e - 28 . The liquid ejecting apparatus  1  in the second embodiment will be described using one example of a case where the cable  19   e  is folded once toward the outside of the plurality of terminals  195   e  and  196   e  in the cut portions  198  and  199 . 
       FIG. 21  is an enlarged diagram of part XXI in  FIG. 20 . In addition, directions x 2 , y 2 , and z 2  that are orthogonal to each other are illustrated in  FIG. 21 . As illustrated in  FIG. 21 , the terminals  196   e - 1  to  196   e - 14  in the end portion of the cable  19   e  are linearly disposed in the direction x 2 . In addition, the terminals  196   e - 15  to  196   e - 28  are linearly disposed in the direction x 2 . 
     In the direction z 2  orthogonal to the direction x 2  in which the terminals  196   e -l to  196   e - 14  are lined up, the terminals  196   e - 1  to  196   e - 14  are respectively disposed in an overlapping manner with the terminals  196   e - 15  to  196   e - 28 . In other words, the terminals  196   e - 1  to  196   e - 14  are respectively disposed in an overlapping manner with the terminals  196   e - 15  to  196   e - 28  in a plan view. Specifically, a terminal  196   e - j  (j is any of 1 to 14) and a terminal  196   e - j+ 14 are disposed in an overlapping manner in a plan view. 
     As described above, by folding the cable  19   e  such that the terminal  196   e - j  (j is any of 1 to 14) and the terminal  196   e -j + 14 overlap in a plan view, the same operation effect as the liquid ejecting apparatus  1  of the first embodiment can be acquired in the liquid ejecting apparatus  1  of the second embodiment. 
     The cable  19   e  is not limited to the form illustrated in  FIG. 20 , provided that the cable  19   e  is folded such that the terminal  196   e - j  (j is any of 1 to 14) and the terminal  196   e - j+ 14 overlap in a plan view. 
     While the embodiments and the modification example are described thus far, the present disclosure is not limited to the embodiments and can be embodied in various aspects without departing from its nature. For example, the embodiments can be appropriately combined. 
     The present disclosure includes substantially the same configuration as the configuration described in the embodiments (for example, a configuration having the same function, method, and result or a configuration having the same application and effect). In addition, the present disclosure includes a configuration acquired by replacing a non-substantial part of the configuration described in the embodiments. In addition, the present disclosure includes a configuration that can achieve the same operation effect or the same application as the configuration described in the embodiments. In addition, the present disclosure includes a configuration acquired by adding a well-known technology to the configuration described in the embodiments.