JP2015223798A - Liquid discharge device and driving method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge device being capable of supplying power to a head unit from a power supply source without using an FFC while securing safety.SOLUTION: A liquid discharge device comprises: a head unit discharging liquid; a carriage 32 being mounted with the head unit and being movable; a high frequency power source unit supplying power for discharging the liquid from the head unit; a housing installed with a power supply source; a first housing side flat plate 91H installed in the housing; and a first carriage side flat plate 91C installed in the carriage 32. The power is transmitted to the carriage 32 from the high frequency power source unit via coupling capacity formed by electric field coupling between the first housing side flat plate 91H and the first carriage side flat plate 91C.

Description

  The present invention relates to a liquid ejecting apparatus such as a printer and a driving method of the liquid ejecting apparatus.

In a printer, a carriage on which a printer head (hereinafter referred to as a head) that discharges ink to a recording medium is mounted is provided inside a casing, and the carriage moves in the main scanning direction. The head is driven by a drive control unit. Here, a printer having a configuration in which a drive control unit and a head are both mounted on a carriage is known. In this type of printer, a print signal for controlling the head is generated by a circuit board provided in the housing. Here, since it is necessary to transmit a print signal from the circuit board to the carriage, the circuit board and the carriage are connected by a flexible flat cable (hereinafter referred to as FFC (Flexible Flat Cable)) having high flexibility. The FFC is also used for power supply from a power supply source installed in the housing to a drive control unit mounted on the carriage.
As described above, since the carriage is a member that moves in the main scanning direction, the FFC tends to be a physical obstacle to the mechanism during the movement. Further, noise is easily applied to a control signal such as a print signal through the FFC. Because of these problems, a technique for configuring a liquid ejection apparatus without using FFC is desired.
In view of the circumstances described above, Patent Document 1 discloses a liquid ejection apparatus in which a timing belt for reciprocating a carriage is made of a conductive material such as metal, and power is supplied to a drive control unit of the carriage via a timing belt and a pulley. Has been proposed. Further, in the liquid ejecting apparatus proposed in Patent Document 1, the control signal is supplied to the carriage using a wireless communication technique.

JP 2011-46118 A

However, when a timing belt made of a conductive material is used, there is a risk of heat generation due to a short circuit when foreign matter such as mist ink adheres to the timing belt that is energized. In addition, when static noise is generated in the timing belt due to a discharge phenomenon called Electro Static Discharge (ESD), the power supplied to the carriage fluctuates, affecting the operation of the drive control unit, which is an electronic circuit. There is a possibility of receiving.
The present invention has been made in view of the above-described circumstances. A drive control unit for a head mounted on a carriage from a power supply source installed in a casing without using an FFC while ensuring safety. An object of the present invention is to provide a liquid ejecting apparatus capable of supplying electric power to.

In order to solve the above problems, an aspect of the liquid ejection device according to the present invention includes a head unit that ejects liquid, a carriage that includes the head unit and is movable, and ejects the liquid from the head unit. A power supply source for supplying electric power to perform, a housing in which the power supply source is installed, a housing-side conductor installed in the housing, and a carriage-side conductor installed in the carriage, The power is transmitted from the power supply source to the carriage via a coupling capacitor formed by electric field coupling between the housing-side conductor and the carriage-side conductor. .
According to this aspect, the electric power is transferred from the housing side to the carriage using the coupling capacitance formed by the electric field coupling between the housing side conductor provided in the housing and the carriage side conductor provided in the carriage. It is transmitted wirelessly to the side. Therefore, it is possible to supply electric power to the head unit mounted on the carriage in a non-contact (non-contact) manner without using the FFC. According to this aspect, it is possible to eliminate the need for FFC with such a simple and highly secure configuration.

Another aspect of the liquid ejection apparatus according to the present invention is the above-described aspect of the liquid ejection apparatus, wherein the casing-side conductor and the carriage-side conductor have a substantially flat plate shape, and the carriage-side conductor is the carriage. The period during which the is moving faces at least a part of the housing-side conductor.
According to this aspect, the casing-side conductor and the carriage-side conductor are a set of substantially flat-plate-shaped conductors. Here, the substantially flat plate shape refers to a substantially flat plate shape. The casing-side conductor provided in the casing is configured to face the carriage-side conductor that moves with the carriage. As a result, it is possible to continuously supply power from the housing side to the moving head unit of the carriage.

Another aspect of the liquid ejection apparatus according to the present invention is the above-described aspect of the liquid ejection apparatus, wherein the liquid ejection apparatus is installed in the housing and electrically connected to the housing-side conductor, and resonates at a first frequency. A transmission-side resonance circuit that is installed on the carriage and is electrically connected to the carriage-side conductor and resonates at a second frequency, and includes the first frequency and the The second frequency is approximately the same.
According to this aspect, it is possible to transmit power with high efficiency by electric field resonance using a resonance phenomenon together with electric field coupling by providing resonance circuits having substantially the same resonance frequency on the transmission side and the reception side in power transmission. it can. Here, “the first frequency and the second frequency substantially coincide with each other” means that the first frequency and the second frequency do not completely coincide with each other, but almost the same effect as when the first frequency coincides completely. It means that it only needs to match to the extent that it can be obtained.

Another aspect of the liquid ejection apparatus according to the present invention is the above-described aspect of the liquid ejection apparatus, wherein the coupling capacitor is provided in a power supply path that supplies power to the carriage from the power supply source installed in the housing. It is characterized by that.
According to this aspect, the coupling capacitance formed by electric field coupling forms at least a part of the power feeding path to the carriage. As a result, a part of the power feeding path can be made wireless, so that FFC can be dispensed with.

Another aspect of the liquid ejection apparatus according to the present invention is the above-described aspect of the liquid ejection apparatus, wherein the coupling capacitor is provided in a discharge path for discharging from the carriage to the power supply source installed in the housing. It is characterized by that.
According to this aspect, the coupling capacitance formed by electric field coupling constitutes at least a part of the discharge path from the carriage. As a result, part of the discharge path can be made wireless, so that FFC can be dispensed with.

Another aspect of the liquid ejection apparatus according to the present invention is the above-described aspect of the liquid ejection apparatus, wherein the head unit includes a nozzle that ejects the liquid, a pressure chamber that communicates with the nozzle, and a pressure chamber. A piezoelectric element provided, wherein the piezoelectric element is driven by the electric power.
According to this aspect, the liquid is discharged by the head unit in a method called a piezo method. Then, relatively large electric power required by the piezoelectric element in the piezo method is wirelessly transmitted from the housing side to the carriage side.

According to another aspect of the liquid ejection apparatus according to the present invention, in the aspect of the liquid ejection apparatus described above, the head unit includes an original drive signal acquisition unit that acquires an original drive signal for driving the piezoelectric element; A class D amplifier that amplifies an original drive signal and supplies the amplified signal to the piezoelectric element.
According to this aspect, the class D amplifier is used to amplify the original drive signal. According to the class D amplifier, it is possible to amplify the drive signal with higher energy efficiency as compared with the linear amplification. Further, the class D amplifier can be reduced in circuit scale. Therefore, mounting the class D amplifier in the head unit is also effective from the viewpoint of reducing the circuit scale.

Another aspect of the liquid ejection apparatus according to the present invention is the liquid ejection apparatus according to the aspect described above, wherein the head unit includes an auxiliary power source, a first signal path to which a first voltage is applied by the auxiliary power source, A second signal path to which a second voltage higher than the first voltage is applied by an auxiliary power source, a signal generation unit that generates a drive signal for driving the piezoelectric element, a voltage of the drive signal, and the piezoelectric A connection path selection unit that electrically connects the piezoelectric element and the auxiliary power source using the first signal path or the second signal path according to a holding voltage of the element, To do.
According to this aspect, the charging or discharging of the piezoelectric element is performed by electrically connecting the piezoelectric element to the first signal path or the second signal path, and the driving signal is used for this electrical connection. In addition to this voltage, the voltage is determined in consideration of the holding voltage of the piezoelectric element, so that the piezoelectric element can be controlled more precisely. In addition, since charging and discharging of the piezoelectric element proceed in stages, energy efficiency can be further increased as compared with the conventional configuration in which charging and discharging progress rapidly. Further, since a large current is not switched unlike a class D amplifier, generation of EMI (Electro-Magnetic Interference) can be suppressed.

Another aspect of the liquid ejection apparatus according to the present invention is the liquid ejection apparatus according to the above aspect, wherein the power supply source uses the power as a drive signal for driving the piezoelectric element via the coupling capacitor. And the carriage rectifies the drive signal to generate a power supply voltage, applies the power supply voltage to the head unit, and the power supply voltage is applied to the carriage based on the drive signal. And a drive unit for driving the piezoelectric element.
According to this aspect, since the drive signal is transmitted to the carriage using the power transmission path using electric field coupling, the parameters necessary for generating the drive signal using FFC are transmitted to the carriage, Compared with the case of generating the drive signal, the configuration can be simplified.

Another aspect of the liquid ejection apparatus according to the present invention is the above-described aspect of the liquid ejection apparatus, wherein the power supply source supplies the power by supplying a voltage signal, and the voltage is supplied to the carriage. A signal processing unit for reducing a frequency component of a signal having a frequency equal to or higher than a predetermined frequency is provided.
According to this aspect, it is possible to reduce the component related to the electrostatic noise in the transmitted power, and it is possible to suppress the malfunction of the electric circuit caused by ESD (Electro Static Discharge).

Another aspect of the liquid ejection apparatus according to the present invention is the above-described aspect of the liquid ejection apparatus, wherein the signal generation unit is provided in the casing and generates a control signal for controlling driving of the piezoelectric element, and the casing. A transmission unit that is provided on a body and wirelessly transmits the control signal to the head unit; and a reception unit that is provided on the carriage and receives the control signal transmitted wirelessly.
According to this aspect, the control signal for controlling the driving of the piezoelectric element is wirelessly transmitted from the housing side to the carriage side. Here, the control signal includes, for example, parameters necessary for generating the drive signal. According to this aspect, FFC can be made unnecessary for transmission of the control signal.

One aspect of a driving method of a liquid discharge apparatus according to the present invention includes: a head unit that discharges liquid; a carriage that is mounted with the head unit and movable; and power that discharges the liquid from the head unit Driving a liquid ejection apparatus comprising: a power supply source to perform; a housing in which the power supply source is installed; a housing-side conductor installed in the housing; and a carriage-side conductor installed in the carriage A method of transmitting the power from the power supply source to the carriage via a coupling capacitance formed by electric field coupling between the first conductor and the second conductor; and the transmitted And the step of discharging the liquid by the head unit using electric power.
According to this aspect, the electric power is transferred from the housing side to the carriage using the coupling capacitance formed by the electric field coupling between the housing side conductor provided in the housing and the carriage side conductor provided in the carriage. It is transmitted wirelessly to the side. Therefore, it is possible to supply electric power to the head unit mounted on the carriage in a non-contact (non-contact) manner without using the FFC. According to this aspect, it is possible to eliminate the need for FFC with such a simple and highly secure configuration.

1 is a block diagram showing a system configuration of a printer according to an embodiment of the present invention. FIG. 2 is a perspective view illustrating an outline of an internal configuration of the printer illustrated in FIG. 1. FIG. 3 is a side sectional view of the printer shown in FIG. 2. The schematic diagram which shows the one aspect | mode of the electric power supply from a power supply unit to a head unit. The figure which shows the structural example of a high frequency power supply unit. The figure which shows the arrangement | sequence of the nozzle in a head. The figure which shows the supply aspect of the signal from a head drive circuit to each nozzle. The figure which shows an example of the waveform of the original drive signal ODRV, the print signal PRT (i), and the drive signal DRV (i). FIG. 6 is a diagram illustrating a configuration example of a power receiving circuit and a head driving circuit. FIG. 3 is a circuit diagram of a circuit including a high-frequency power supply unit, a housing-side first flat plate, a carriage-side first flat plate, a housing-side second flat plate, a carriage-side second flat plate, a power receiving circuit, and a head driving circuit. The figure which shows the equivalent circuit of the circuit shown in FIG. FIG. 12 is a diagram showing a part of the circuit shown in FIG. 11. FIG. 12 is a diagram showing the circuit shown in FIG. 11 divided into three parts from a functional viewpoint. The figure which shows an example of a general two terminal pair circuit. The figure which shows the circuit which applied the element of the two terminal pair circuit shown in FIG. 13 to the two terminal pair circuit shown in FIG. The figure which shows the equivalent circuit of the two-terminal pair circuit equivalent to the 2nd part shown in FIG. The circuit diagram of the electric power transmission path | route of the printer which concerns on a modification. The figure which shows the structure peculiar to a 2nd application example. The figure which shows the structural example of the receiving circuit and head drive circuit in a 3rd application example. The schematic diagram which shows an example of the arrangement | positioning aspect of a housing | casing side 1st flat plate, a housing | casing side 2nd flat plate, a carriage side 1st flat plate, and a carriage side 2nd flat plate. The schematic diagram which shows an example of the arrangement | positioning aspect of a housing | casing side 1st flat plate, a housing | casing side 2nd flat plate, a carriage side 1st flat plate, and a carriage side 2nd flat plate.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, in each figure, the size and scale of each part are appropriately changed from the actual ones. Further, since the embodiments described below are preferable specific examples of the present invention, various technically preferable limitations are attached thereto. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these forms.

Hereinafter, a serial ink jet printer (hereinafter referred to as a printer) will be described as an example of the liquid ejection apparatus according to the present embodiment.
FIG. 1 is a block diagram illustrating a system configuration of the printer 1. FIG. 2 is a perspective view showing the internal configuration of the printer 1. FIG. 3 is a side sectional view of the printer shown in FIG.
The printer 1 forms an electric field coupling with the casing 3, the high frequency power supply unit 5, the controller 10, the transport unit 20, the carriage 32, the head unit 40 provided on the carriage 32, and the detector group 50. A flat conductor (in this embodiment, a housing-side first flat plate 91H and a carriage-side first flat plate 91C, and a housing-side second flat plate 92H and a carriage-side second flat plate 92C). The printer 1 is used by connecting to a computer 110 that is an external device, for example.
When the printer 1 receives print data transmitted from the computer 110, the controller 10 controls each unit to form an image on a recording sheet (hereinafter referred to as a sheet) S that is a recording medium. At that time, the situation in the printer 1 is monitored by the detector group 50, and the controller 10 controls each unit based on the detection result.

The housing 3 includes a box that accommodates each component member, and a mechanical frame 3a made of a conductive material such as metal provided inside the box.
The high frequency power supply unit 5 is fixed to the housing 3 and supplies electric power required on the head unit 40 side. That is, the high frequency power supply unit 5 functions as a power supply source (power source) that supplies power required for ink ejection by the head unit 40. The high frequency power supply unit 5 is connected to a household AC outlet or the like via an electric cord or the like, and generates an AC voltage. The waveform of the AC voltage is, for example, a sine wave of about 2.9 MHz. The high frequency power supply unit 5 outputs a first high frequency voltage signal and a second high frequency voltage signal in a differential format. The waveform of the second high frequency voltage signal is an inversion of the waveform of the first high frequency voltage signal. The first high-frequency voltage signal and the second high-frequency voltage signal are generated by a plate-like conductor that forms electric field coupling (a housing-side first flat plate 91H and a carriage-side first flat plate 91C, and a housing-side second flat plate 92H and a carriage-side first electrode. 2 plate 92C) and wirelessly transmitted to the head unit 40 side.

Power is calculated by the product of voltage and current (power P [W] = voltage E [V] · current I [A]). To transmit power, the power is generated from the power source that generates power toward the load. Therefore, a power supply path for supplying current and a discharge path for returning current from the load to the power source are required. That is, the power source is electrically connected to the load through the power supply path and the discharge path, and the power source applies a power supply voltage to the power supply path and the discharge path. More specifically, a power supply voltage provided as a potential difference between the first power supply signal and the second power supply signal by supplying the first power supply signal to the power supply path and supplying the second power supply signal to the discharge path. Is applied to the power supply path and the discharge path.
In the present embodiment, “supplying power” is a concept including applying a power supply voltage to the power supply path and the discharge path and supplying a power signal to at least one of the power supply path and the discharge path.

  The configuration of the high frequency power supply unit 5 and the transmission of the high frequency voltage signal will be described in detail later with reference to the drawings. The printer 1 includes a power supply unit (not shown) that is connected to a household AC outlet and functions as a DC power source.

  The controller 10 is also fixed to the housing 3. The controller 10 includes an interface unit 11, a CPU 12, a memory 13, a unit control circuit 14, and a transmitter 17. The interface unit 11 transmits and receives data between the computer 110 and the printer 1. The CPU 12 is an arithmetic processing unit that controls the entire printer 1, and controls each unit via the unit control circuit 14. The memory 13 secures an area for storing a program of the CPU 12, a work area, and the like. The transmitter 17 wirelessly transmits various signals such as a print signal PRT described later.

The transport unit 20 feeds the paper S to a printable position, and transports the paper S by a predetermined transport amount in the transport direction during printing as shown in FIGS. 2 and 3. A conveyance motor 22, a conveyance roller 23, a platen 24, and a paper discharge roller 25 are included. The paper feed roller 21 sends the paper S placed on the tray 77 to the position of the transport roller 23.
When the paper detection sensor 51, which is one of the detector groups 50 shown in FIG. 1, detects the leading edge of the paper S sent toward the transport roller 23, the controller 10 rotates the transport roller 23 and the paper S Is positioned at the print start position.
When the paper S is positioned at the print start position, at least some of the nozzles N on the lower surface 41a of the head 41 are opposed to the paper S. The platen 24 is provided at a position that can face the lower surface 41a of the head 41, and supports the sheet S during printing from below.

The carriage 32 is provided with a head unit 40, a receiver 37, a power receiving circuit 59, a carriage-side first flat plate 91C, and a carriage-side second flat plate 92C.
The carriage 32 is supported and guided by a guide rail 36 fixed to the housing 3 and reciprocates in a direction (carriage movement direction) intersecting the conveyance direction shown in FIG. Specifically, the carriage 32 uses a carriage motor 33 provided in the housing 3 as a power source, a part of the timing belt 35 is fixed, and moves by sending out the timing belt 35.

  The guide rail 36 that functions as a support portion of the carriage 32 is, for example, a substantially columnar member (shaft body) whose longitudinal direction (axial direction) is the movement direction of the carriage 32. Here, the carriage 32 is formed with a through hole penetrating in the moving direction, and the guide rail 36 is inserted into the through hole.

As shown in FIG. 2, the timing belt 35 is hung (passed around) the first pulley 34 a and the second pulley 34 b, and the driving force of the carriage motor 33 is transmitted to the timing belt 35 through them. Sent out.
Here, since a part of the timing belt 35 is fixed to the carriage 32, when the second pulley 34b is rotationally driven by the carriage motor 33 and the timing belt 35 is sent out, the carriage 32 moves in the carriage movement direction. That is, the head 41 moves in the carriage movement direction with respect to the paper S.

  The receiver 37 receives a signal wirelessly transmitted by the transmitter 17 of the controller 10 and supplies the signal to the head drive circuit 61 of the head unit 40. This signal is specifically a control signal for driving the head 41 of the head unit 40. For example, a print signal PRT generated by the unit control circuit 14 of the controller 10, an original drive signal generation parameter (described later), and the like. It is.

The head unit 40 includes a head 41 for ejecting ink droplets onto the paper S, and a head drive circuit 61 for driving the head 41 to eject ink droplets from the nozzles N of the head 41, and is mounted on the carriage 32. Yes.
The head 41 includes a piezoelectric element that is displaced by charging and discharging, a cavity, and a nozzle N. The cavity is filled with liquid (ink), and the internal pressure is increased or decreased by the displacement of the piezoelectric element. The nozzle N communicates with the cavity, and ejects liquid (ink) inside the cavity as droplets by increasing or decreasing the pressure in the cavity.
As shown in FIG. 3, a plurality of nozzles N are provided on the lower surface 41a of the head 41. Each nozzle has an ink chamber containing ink, and a drive for ejecting ink droplets by changing the capacity of the ink chamber. A piezoelectric element is provided as an element. The head driving circuit 61 drives the piezoelectric element based on the print signal PRT and the like, thereby ejecting ink droplets.
In the printer 1 having such a configuration, ink droplets are intermittently ejected from the head 41 moving along the carriage movement direction, and a dot forming operation for forming dots on the paper S and the paper S are conveyed in the conveyance direction. The transfer operation is repeated alternately. By doing so, a dot row is formed at a position different from the dot row (raster line) formed by the previous dot forming operation in the transport direction, and thus an image is completed on the paper S.
The detector group 50 includes a linear encoder 52 (see FIG. 2), a rotary encoder 53 (see FIG. 3), and the like. The linear encoder 52 detects the position of the carriage 32. The rotary encoder 53 detects the rotation amount of the transport roller 23.

In the printer 1 according to the present embodiment, the housing-side first flat plate 91H is provided on the platen 24 (see FIG. 3), and the carriage-side first flat plate 91C that forms electric field coupling with the housing-side first flat plate 91H. Is provided on the carriage 32.
Here, the housing-side first flat plate 91H and the carriage-side first flat plate 91C are configured to continue to face each other even during the movement period of the carriage 32. That is, the housing-side first flat plate 91H is provided with a size and a position corresponding to the moving range of the carriage 32 so as to face the carriage-side first flat plate 91C even if the carriage 32 moves.
In addition, the arrangement | positioning aspect of the housing | casing side 1st flat plate 91H and the carriage side 1st flat plate 91C is not restricted to the example shown in FIG. That is, the housing-side first flat plate 91H is installed in the housing 3 so that the housing-side first flat plate 91H and the carriage-side first flat plate 91C can form electric field coupling, and the carriage-side first flat plate 91C is attached to the carriage 32. It only has to be installed.

Further, the housing-side second flat plate 92H, which is a conductive flat plate, is located on a portion (hereinafter referred to as a top plate) 3t facing the upper surface of the carriage 32 (including the ink cartridge 31) of the housing 3 as shown in FIG. A carriage-side second flat plate 92 </ b> C that is provided and forms electric field coupling with the housing-side second flat plate 92 </ b> H is provided on the upper surface of the carriage 32.
Here, the housing-side second flat plate 92H and the carriage-side second flat plate 92C are configured to continue to face each other even during the movement period of the carriage 32. That is, the housing-side second flat plate 92H is provided with a size and a position corresponding to the movement range of the carriage 32 so as to face the carriage-side second flat plate 92C even if the carriage 32 moves.

The arrangement of the housing-side second flat plate 92H and the carriage-side second flat plate 92C is not limited to the example shown in FIG. That is, the housing-side second flat plate 92H is installed in the housing 3 so that the housing-side second flat plate 92H and the carriage-side second flat plate 92C can form electric field coupling, and the carriage-side second flat plate 92C is attached to the carriage 32. It only has to be installed.
In the present embodiment, the conductors forming the electric field coupling have flat plate shapes such as the housing-side first flat plate 91H, the carriage-side first flat plate 91C, the housing-side second flat plate 92H, and the carriage-side second flat plate 92C. Although a conductor is employed, the conductor is not limited to a flat plate shape as long as the electric field coupling can be formed, and a conductor having an arbitrary shape may be employed.

  The printer 1 can also perform bidirectional printing, that is, it can also form an image by ejecting ink droplets toward the paper S in the forward and backward paths in the carriage movement direction. In that case, the sheet S is transported between the forward and backward dot forming operations.

Hereinafter, a power supply mode from the high frequency power supply unit 5 to the head unit 40 will be described. FIG. 4 is a schematic diagram showing an aspect of power supply from the high frequency power supply unit 5 to the head unit 40.
As shown in the figure, the first output terminal TE1 of the high-frequency power supply unit 5 is electrically connected to the housing-side first flat plate 91H, and the second output terminal TE2 of the high-frequency power supply unit 5 is electrically connected to the housing-side second flat plate 92H. Connected.
Here, the housing-side first flat plate 91H forms electric field coupling with the carriage-side first flat plate 91C provided on the carriage 32, and the housing-side second flat plate 92H is formed with the carriage-side second flat plate 92C provided on the carriage 32. Form electric field coupling.
In the present embodiment, the electric power generated in the high frequency power supply unit 5 is transmitted to the head unit 40 via the power supply path and the discharge path. Here, the power supply path is a path through which a current flows from the high frequency power supply unit 5 toward the head unit 40. On the other hand, the discharge path is a path in which current returns from the head unit 40 toward the high frequency power supply unit 5.
The coupling capacitance formed by electric field coupling between the housing-side first flat plate 91H and the carriage-side first flat plate 91C constitutes at least a part of the power feeding path. On the other hand, the coupling capacitance formed by electric field coupling between the housing side second flat plate 92H and the carriage side second flat plate 92C constitutes at least a part of the discharge path. With this configuration, non-contact (non-contact) power transmission can be performed between the high-frequency power supply unit 5 and the head unit 40.

The first high-frequency voltage signal output from the first output terminal TE1 of the high-frequency power supply unit 5 is transmitted to the head unit 40 side via the housing-side first flat plate 91H and the carriage-side first flat plate 91C, and the second The second high-frequency voltage signal output from the output terminal TE2 is transmitted to the head unit 40 side via the housing-side second flat plate 92H and the carriage-side second flat plate 92C.
That is, in the printer 1 according to this embodiment, power is supplied to the head unit 40 by transmitting a high-frequency voltage signal from the high-frequency power supply unit 5 to the head unit 40 via a coupling capacitor formed by electric field coupling.
With this configuration, the FFC that electrically connects the high-frequency power supply unit 5 and the head unit 40 becomes unnecessary. Accordingly, various problems caused by the FFC are solved, and it is not necessary to separately provide a current-carrying member instead of the FFC for power supply. A configuration without risk of occurrence is realized.

FIG. 5 is a diagram illustrating a configuration example of the high-frequency power supply unit 5. As shown in the figure, the high frequency power supply unit 5 includes a high frequency signal generation unit 5-1, a transmission-side resonance circuit 5-2, a first output terminal TE1, and a second output terminal TE2. The first output terminal TE1 is electrically connected to the housing side first flat plate 91H, and the second output terminal TE2 is electrically connected to the housing side second flat plate 92H.
The transmission-side resonance circuit 5-2 includes a primary-side capacitive element C1 and a primary-side inductance element L1 connected in parallel to the high-frequency signal generation unit 5-1, and two connected in parallel between the output terminals TE1 and TE2. The secondary side capacitive element C2 and the secondary side inductance element L2 are provided. The secondary inductance element L2 is provided so as to form inductive coupling with the primary inductance element L1. The primary side inductance element L1 and the secondary side inductance element L2 are constituted by a transformer or the like. The transmission-side resonance circuit 5-2 resonates at the first frequency.

  FIG. 6 is a diagram showing the arrangement of nozzles N in the head 41. On the lower surface 41a of the head 41, a nozzle row 411 including a plurality of (for example, 180) nozzles # 1 to #n for each color of black (K), cyan (C), magenta (M), and yellow (Y). Is provided. The nozzles # 1 to #n included in the nozzle row 411 are linearly aligned at a predetermined nozzle pitch Px (for example, 180 dpi) along the transport direction of the paper S. In addition, the nozzle rows 411 are arranged in parallel to each other with an interval in the carriage movement direction.

The head drive circuit 61 is provided for each nozzle row 411, that is, for each nozzle row 411 of each color of black (K), cyan (C), magenta (M), and yellow (Y). FIG. 7 is a diagram showing how signals are supplied from the head drive circuit 61 to the nozzles # 1 to #n.
The head drive circuit 61 includes an original drive signal generation unit 63 and a drive signal shaping unit 65 as shown in the figure, and drives and controls each part of the head unit 40. The head driving circuit 61 drives the piezoelectric element for each of the nozzles # 1 to #n. In the figure, the numbers in parentheses at the end of each signal name indicate the number of the nozzle to which the signal is supplied.
When a voltage of a predetermined time width is applied between the electrodes provided at both ends of the piezoelectric element provided in each nozzle, the piezoelectric element expands according to the voltage application time and deforms the side wall of the ink flow path. As a result, the volume of the ink flow path contracts in accordance with the expansion and contraction of the piezoelectric element, and the ink amount corresponding to the contraction amount is ejected from the nozzles # 1 to # 180 of each color as ink droplets.

As shown in FIG. 7, the original drive signal generator 63 receives parameters for generating an original drive signal that defines the waveform shape of the original drive signal ODRV. Based on this original drive signal generation parameter, the original drive signal generator 63 generates an original drive signal ODRV that is used in common by the nozzles # 1 to #n.
FIG. 8 is a diagram illustrating an example of waveforms of the original drive signal ODRV, the print signal PRT (i), and the drive signal DRV (i). In this example, the original drive signal ODRV has two pulses of a first pulse W1 and a second pulse W2, as shown in FIG. 8, within a period of one pixel (within a time during which the carriage 32 crosses the interval of one pixel). It is a signal containing.
As shown in FIG. 7, the drive signal shaping unit 65 receives the original drive signal ODRV from the original drive signal generation unit 63 and the print signal PRT based on the print data. The print signal PRT is a signal corresponding to pixel data assigned to one pixel. That is, the print signal PRT is a signal corresponding to the pixel data included in the print data.

The drive signal shaping unit 65 blocks or passes the original drive signal ODRV for each nozzle (i) based on the print signal PRT (i) corresponding to each nozzle (i). For example, as shown in FIG. 8, when the print signal PRT (i) is a 2-bit signal “00”, the first pulse W1 and the second pulse W2 of the original drive signal ODRV are cut off, and the print signal PRT When (i) is “01”, only the first pulse W1 is cut off and the second pulse W2 is allowed to pass. When the print signal PRT (i) is “10”, the second pulse W2 is passed. The first pulse W1 is allowed to pass, and when the print signal PRT (i) is “11”, the first pulse W1 and the second pulse W2 are allowed to pass.
Then, the drive signal shaping unit 65 outputs the passed pulse as the drive signal DRV (i) toward the piezoelectric element of each nozzle (i). The piezoelectric element of each nozzle (i) is driven based on the drive signal DRV (i) from the drive signal shaping unit 65 to discharge ink droplets.

FIG. 9 is a diagram illustrating a system configuration of the power receiving circuit 59 and the head driving circuit 61 provided in the carriage 32. The power reception circuit 59 includes a reception-side resonance circuit 55, a rectification circuit 57, an input-side first terminal 54P, an input-side second terminal 54G, an output-side first terminal 58P, and an output-side second terminal 58G. Prepare.
A carriage-side first flat plate 91C is connected to the input-side first terminal 54P of the power receiving circuit 59, and a carriage-side second flat plate 92C is connected to the input-side second terminal 54G.

  The reception-side resonance circuit 55 is connected in parallel to the primary-side capacitive element C3, the primary-side inductance element L3, and the rectifier circuit 57 that are connected in parallel between the input-side first terminal 54P and the input-side second terminal 54G. A secondary-side capacitive element C4 and a secondary-side inductance element L4 connected to each other. The secondary inductance element L4 is provided so as to form inductive coupling with the primary inductance element L3. The reception side resonance circuit 55 resonates at the second frequency. Here, the second frequency substantially coincides with the first frequency. As a result, power can be transmitted from the high frequency power supply unit 5 to the head unit 40 with high efficiency (voltage transmission coefficient equal to or greater than a predetermined value).

  The rectifier circuit 57 rectifies the output voltage of the reception side resonance circuit 55 and outputs the power supply voltage Vx. The power supply voltage Vx is given as a potential difference between the predetermined potential VDD and the reference potential VSS. The power supply voltage Vx is applied to the head drive circuit 61. More specifically, the rectifier circuit 57 supplies the first power supply signal whose level is the predetermined potential VDD to the output-side first terminal 58P, and outputs the second power supply signal whose level is the reference potential VSS to the output-side second. Supply to terminal 58G. The rectifier circuit 57 is an AC-DC converter, for example.

The head drive circuit 61 includes a power supply terminal 62P, a ground terminal 62G, an original drive signal generation unit 63, a drive signal shaping unit 65, and a DC-DC converter 67 as shown in FIG.
The power supply terminal 62P of the head driving circuit 61 is connected to the output-side first terminal 58P of the power receiving circuit 59, and a first power supply signal whose level is the predetermined potential VDD is input. The ground terminal 62G of the head driving circuit 61 is connected to the output-side second terminal 58G of the power receiving circuit 59, and a second power supply signal whose level is the reference potential Vss is input.
Here, the operations of the original drive signal generation unit 63 and the drive signal shaping unit 65 are as described above with reference to FIGS. In addition, the DC-DC converter 67 uses the voltage input from the power supply terminal 62P and the ground terminal 62G as an appropriate voltage required by each part of the head drive circuit 61 (3.3 V in the example shown in the figure). It may be provided as necessary.

FIG. 10 shows an equivalent circuit of the high-frequency power supply unit 5, the housing side first flat plate 91H, the carriage side first flat plate 91C, the housing side second flat plate 92H, the carriage side second flat plate 92C, and the power receiving circuit 59. In the figure, the power supply Vs is equivalent to a high-frequency signal generating unit 5-1 shown in FIG. 5, the two coupling impedance Z _M set of flat plates respectively field coupling (housing side first flat plate 91H and the carriage-side first This corresponds to the impedance of the coupling capacitance formed by the flat plate 91C or the housing-side second flat plate 92H and the carriage-side second flat plate 92C), and the load _RL indicates the load of the circuit related to the subsequent stage of the reception-side resonance circuit 55. Yes.

FIG. 11 shows an equivalent circuit in which the equivalent circuit shown in FIG. 10 is expressed by a four-terminal network. In the figure, the internal resistance Rs of the power supply Vs shown in FIG. 10 is shown, and the inductance _{L A} and capacitor _{C A} corresponds to the transmission side resonance circuit 5-2 shown in FIG. 5, the inductance _{L B} and capacitor _{C B} Corresponds to the reception-side resonance circuit 55 shown in FIG. In the equivalent circuit shown in FIG. 11, assuming that the center potential of the voltage generated by the power supply Vs is used as a reference, the equivalent circuit shown in FIG. 12 is obtained. In the following, the circuit shown in FIG. 12 will be considered for easy calculation.

Here, for convenience of calculation, letters indicating values relating to the respective elements in the circuit shown in FIG. 12 are replaced as follows. That is,
Rs / 2 = R _L / 2 = z ₀
L _A / 2 = L _B / 2 = L
2C _A = 2C _B = C
Z _M = R
And The circuit diagram shown in FIG. 13 is represented by the circuit shown in FIG. 13 while the circuit shown in FIG. In the figure, a first part 300 is a part mainly responsible for a power supply function, a two-terminal pair circuit 301 as a second part is a part mainly responsible for a power transmission function (high-frequency voltage signal transmission function), and a third part 302 is It is a portion corresponding to a load that operates by the transmitted power.

Hereinafter, the voltage transmission coefficient of the two-terminal pair circuit 301 that assumes the power transmission function is calculated. The voltage transmission coefficient is a coefficient indicating how much the voltage applied to the input terminal of the two-terminal-pair circuit is transmitted to the output terminal, and is a scattering matrix (scattering matrix) that is one of the network parameters representing the characteristics of high-frequency electronic circuits, etc. matrix; represented as an element _{s 21} of S also referred parameters). A value (| s ₂₁ | ² ) obtained by squaring the absolute value of the voltage transmission coefficient s ₂₁ indicates a power gain when the impedance of the power source and the load is Z ₀ .

Here the voltage transmission coefficient s _21, the two-terminal pair circuit of the impedance matrix; can be obtained from (Impedance matrix also referred Z parameter).
Here, first, an admittance matrix (also referred to as Y parameter) of the two-terminal pair circuit 301 is calculated, an impedance matrix is obtained as an inverse thereof, and a known calculation formula for obtaining a scattering matrix from the impedance matrix is used. Find the scattering matrix. Then, a voltage transmission coefficient s ₂₁ that is an element of the scattering matrix is obtained. Further, the power gain | s ₂₁ | ² is obtained from the value of the voltage transmission coefficient s ₂₁ . Hereinafter, the calculation process will be described in order.

が成立するため、アドミタンス行列（Ｙパラメーター）は次のように求まる。すなわち、アドミタンス行列の各要素は、Ｙ_１１＝Ｙ_１＋Ｙ_２、Ｙ_１２＝−Ｙ_２、Ｙ_２１＝−Ｙ_２、Ｙ_２２＝Ｙ_２＋Ｙ_３である。 First, the two-terminal pair circuit 301-1 (see FIG. 13) excluding the inductance L of the two-terminal pair circuit 301 will be considered. FIG. 14 is a diagram illustrating a two-terminal pair circuit in which elements of the two-terminal pair circuit 301-1 are generalized. In the two-terminal pair circuit shown in the figure,

Therefore, the admittance matrix (Y parameter) is obtained as follows. That is, each element of the admittance matrix is Y ₁₁ = Y ₁ + Y ₂ , Y ₁₂ = −Y ₂ , Y ₂₁ = −Y ₂ , and Y ₂₂ = Y ₂ + Y ₃ .

であり、

である。
そして、図１４に示す二端子対回路のアドミタンス行列の各要素が上述したように表されることから、二端子対回路３０１−１のアドミタンス行列は、下記（式４）のように求まる。

Based on this, the Y parameter of the two-terminal pair circuit 301-1 shown in FIG. 13 is obtained. FIG. 15 is a diagram showing a circuit in which the elements C 1 and R 2 of the two-terminal pair circuit 301-1 are fitted to the generalized elements Y ₁ , Y ₂ and Y ₃ of the two-terminal pair circuit shown in FIG. It is. here,

And

It is.
Then, since each element of the admittance matrix of the two-terminal pair circuit shown in FIG. 14 is expressed as described above, the admittance matrix of the two-terminal pair circuit 301-1 is obtained as shown below (Formula 4).

Using this way the obtained admittance matrix Y, impedance matrix of two-terminal pair circuit 301-1 (referred to as an impedance matrix Z _2), the inverse matrix of the admittance matrix Y represented by (Equation 4) Y ^-1 Can be obtained as
Here, the two-terminal pair circuit 301-1 shown in FIG. 15 does not include an element corresponding to the inductance L among the elements of the two-terminal pair circuit of the two-terminal pair circuit 301 shown in FIG. 13. Therefore, the impedance matrix Z ₂ serving inverse matrix of (Formula 4) is calculated as the admittance matrix, the inductance L is not reflected in the two-port network 301, it is necessary to reflect this.

FIG. 16 is a diagram showing an equivalent circuit of the two-terminal pair circuit 301. A two-terminal pair circuit 301-2 in the figure is a two-terminal pair circuit obtained by removing elements other than the inductance L in the two-terminal pair circuit 301. Accordingly, the two-terminal pair impedance matrix circuit 301-2 When _{Z 4,} second impedance matrix Z terminal pair circuit 301, the following (Equation 5) as in the impedance matrix _{Z 2} of the two-terminal pair circuit 301-1 When determined as the sum of the impedance matrix _{Z 4} of the two-terminal pair circuit 301-2.
Z = Z ₂ + Z ₄ (Formula 5)

と表される。
そしてインピーダンスｚ_１及びｚ_３は、それぞれインダクタンスＬに係るインピーダンスであるから、
ｚ_１＝ｚ_３＝ｊωＬ …（式７）
である。 Here, the impedance matrix Z ₄ of the two-terminal pair circuit 301-2 is:

It is expressed.
Since the impedances z ₁ and z ₃ are impedances related to the inductance L, respectively.
z ₁ = z ₃ = jωL (Expression 7)
It is.

この（式９）の右辺を整理すると、二端子対回路３０１のインピーダンス行列Ｚは、下記（式１０）で表される。

となる。 Further, since the impedance matrix Z ₂ of the two-terminal pair circuit 301-1 is the inverse matrix of the admittance matrix Y of the two-terminal pair circuit 301-1, as described above,
Z2 = Y ⁻¹ (Formula 8)
Therefore, the impedance matrix Z of the two-terminal pair circuit 301 is expressed by the following (formula 9).

If the right side of this (Formula 9) is arranged, the impedance matrix Z of the two-terminal pair circuit 301 is represented by the following (Formula 10).

It becomes.

ここで本例では、（式１０）に示すように、インピーダンス行列Ｚの要素について、ｚ_１１＝ｚ_２２、ｚ_１２＝ｚ_２１という関係が成立している。この場合、インピーダンス行列から散乱行列を求める式は下記（式１２）となる。

この（式１２）から、ｓ_２１は下記のように求まる。

ここで、（式１３）の右辺からＺ_１１とＺ_１２とを消去するために、（Ｚ_１１＋Ｚ_１２）の値、及び（Ｚ_１１−Ｚ_１２）の値を算出する。 By the way, in order to obtain the scattering matrix from the impedance matrix, for example, the following known (formula 11) is used.

In this example, as shown in (Equation 10), the relationship of z ₁₁ = z ₂₂ and z ₁₂ = z ₂₁ holds for the elements of the impedance matrix Z. In this case, the equation for obtaining the scattering matrix from the impedance matrix is as follows (Equation 12).

From this equation _{(12), s 21} is obtained as follows.

Here, to calculate the value of to clear the _{Z 11} and _{Z 12} from the right side of equation _(13), the value of (Z 11 _{+ Z 12)} and, _(Z 11 _{-Z 12).}

そして、（式１５）及び（式１６）を用いて（式１３）からｚ_１１とｚ_１２を消去すると、ｓ_２１が次のように求まる。

従って、電力利得を示す｜ｓ_２１｜^２の値は次のように求まる。

さらに、上述した共振条件を示す（式１４）の関係式を用いて、（式１８）からＣを消去すると、｜ｓ_２１｜^２の値は次のように表せる。

First, in this embodiment, as described above, in order to perform power transmission with high efficiency using the LC resonance phenomenon, various conditions are set so as to satisfy the resonance condition of the following (formula 14).
ω ² LC = 1 (Expression 14)
Using the relational expression of (Expression 14), when L is eliminated from z ₁₁ and z ₁₂ shown in (Expression 10) and their sum and difference are calculated, (Expression 15) and (Expression 16) are can get.
z ₁₁ + z ₁₂ = 0 (Formula 15)

Then, by eliminating z ₁₁ and z ₁₂ from (Equation 13) using (Equation 15) and (Equation 16), s ₂₁ is obtained as follows.

Therefore, the value of | s ₂₁ | ² indicating the power gain is obtained as follows.

Further, if C is eliminated from (Expression 18) using the relational expression (Expression 14) indicating the resonance condition described above, the value of | s ₂₁ | ² can be expressed as follows.

When indicating the value of ² power gain according to the two-port network 301, the _| ^| This represented by (Equation 19) _{^| s} 21 _s 21 _| ^{when two} values becomes the maximum, according to the two-port network 301 Power transmission efficiency is highest.
Here, when the denominator on the right side is minimum in (Equation 19), the value of | s ₂₁ | ² is maximum. The denominator on the right side is minimized when the following equation (20) is satisfied.
z ₀ << R << ωL (Expression 20)

When (Equation 19) is modified so as to satisfy the relational expression of (Equation 20), the value of | s ₂₁ | ² is approximated as follows.

このとき、（式２２）から、ωＬの値が下記（式２３）のように導出される。

従って、（式２０）と（式２３）とを共に満たすように各値を設定することで、９０％を超える二端子対回路３０１の電力利得を得ることが可能となる。つまり、高周波電源ユニット５からヘッドユニット４０へ高効率で電力を伝送することが可能となる。 Here, as shown in the following (formula 22), it is assumed that the value of | s ₂₁ | ² indicating the power gain exceeds 0.9.

At this time, the value of ωL is derived from (Expression 22) as shown in (Expression 23) below.

Therefore, by setting each value so as to satisfy both (Equation 20) and (Equation 23), it is possible to obtain a power gain of the two-terminal pair circuit 301 exceeding 90%. That is, power can be transmitted from the high frequency power supply unit 5 to the head unit 40 with high efficiency.

Of the conditional expressions shown as (Expression 20), regarding the condition of z ₀ << R, the internal resistance Rs of the power source Vs corresponding to the impedance z ₀ can be set to several tens of Ω or less, and the coupling capacitance C _M The impedance R according to the above is normally satisfied because it is a very large impedance compared to several tens of ohms. Therefore, the condition of R << ωL among the conditional expressions shown as (Expression 20) will be examined below.

First, the relationship of the following (formula 24) is obtained from R << ωL.
ωL / R << 1 (Formula 24)
Meanwhile impedance R is because impedance of the coupling capacitance C _M, represented by the following equation (25).
R = 1 / (jωC _M ) (Formula 25)
Thus the magnitude of the complex representation impedance R is Motomari a 1 / .omega.C _M, when erasing the R by substituting this value into equation (24), the following relationship (Equation 26) is obtained.
1 / (ω ² LC _M ) << 1 (Equation 26)
Further, when the relational expression (Expression 14) indicating the resonance condition described above is used to eliminate ω and L from (Expression 26), the following relation (Expression 27) is obtained.
C << C _M (Formula 27)
Therefore, if the setting of the C and C _M so as to satisfy the equation (27), the condition of R << .omega.L of conditional expression (Expression 20) is satisfied. For this purpose, for example in terms of setting the value of realization easy lowest and C, may be set C _M such that several times greater than the value of the C.

As described above, according to the present embodiment, it is possible to provide a liquid ejection apparatus capable of supplying power from the high-frequency power supply unit 5 to the head unit 40 with high efficiency without using FFC while ensuring safety. it can.
The above-described embodiments are for facilitating understanding of the present invention, and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.

<Modification>
In order to avoid duplication of explanation, explanation of the common points between the above-described embodiment of the present invention and this modification will be omitted, and only differences will be explained. The difference is that the ground terminal 62G of the head drive circuit 61 is electrically grounded using the guide rail 36 in this modification.
Specifically, a conductive portion is provided over substantially the entire length along the longitudinal direction of the guide rail 36, and this conductive portion is connected to the electrically grounded mechanical frame 3a and grounded. Then, the ground terminal 62G of the head drive circuit 61 is brought into sliding contact with the conductive portion of the guide rail 36 via a brush member or the like. As a result, the ground terminal 62G of the head drive circuit 61 is electrically grounded via the guide rail 36, and a discharge path from the head drive circuit 61 is formed.

The power supply path may be configured using electric field coupling between the housing-side first flat plate 91H and the carriage-side first flat plate 91C, as in the printer 1 according to the embodiment described above.
Specifically, in the printer 1 according to this modification, power transmission including the high frequency power supply unit 5, the housing-side first flat plate 91 </ b> H, the carriage-side first flat plate 91 </ b> C, the power receiving circuit 59, and the head driving circuit 61. The path is represented by a circuit diagram shown in FIG.
The main difference from the circuit diagram of the power transmission path in the printer 1 according to the embodiment described above (see FIG. 10) is that the coupling impedance Z _M of the coupling capacitance formed by the electric field coupling there is only one It is. The circuit shown in FIG. 17 is equivalent to the circuit shown in FIG. 12 described above. Therefore, the conditions for transmitting power from the high frequency power supply unit 5 to the head unit 40 with high efficiency are the same as those in the printer 1 according to the first embodiment.

<< First application example >>
In order to avoid duplication of description, description of the common points between the above-described embodiment of the present invention and the first application example will be omitted, and only differences will be described. The difference is that in the printer 1 according to the first application example, a class D amplifier is provided in the head drive circuit 61 in order to amplify the original drive signal ODRV.
As described above, the head 41 is provided with a piezoelectric element as a drive element for ejecting ink droplets by changing the capacity of the ink chamber. The head driving circuit 61 drives the piezoelectric element based on the print signal PRT and the like, thereby ejecting ink droplets.
Here, the piezoelectric element is provided corresponding to each of the plurality of nozzles N in the head 41, and each is driven according to a control signal, thereby ejecting a predetermined amount of ink from the nozzle N at a predetermined timing. Since the piezoelectric element is a capacitive load like a capacitor when viewed electrically, it is necessary to supply a sufficient current to operate the piezoelectric element of each nozzle N. Therefore, a configuration in which the original drive signal is amplified by an amplifier circuit and the piezoelectric element is driven using the amplified signal may be employed.
In this example, a class D amplifier is used to amplify the original drive signal. That is, a method is employed in which the original drive signal is modulated by pulse width modulation or pulse density modulation and then demodulated by a low-pass filter. According to the class D amplification, the original drive signal can be amplified with higher energy efficiency compared to the linear amplification. In addition, since the class D amplifier can be reduced in circuit scale, mounting the class D amplifier as an amplifier in the head unit 40 is also advantageous from the viewpoint of circuit scale.

<< Second application example >>
In order to avoid duplication of description, description of the common points between the embodiment of the present invention described above and the second application example will be omitted, and only differences will be described. The printer 1 according to the second application example is provided with a driver 230 (see FIG. 18) and an auxiliary power supply circuit 250 (see FIG. 18) in the subsequent stage of the original drive signal generating unit 63. FIG. 18 is a diagram illustrating a configuration unique to the second application example.
In response to the voltage Vout held by the piezoelectric element 240, the driver 230 selects a connection path (described later) between the piezoelectric element 240 and the auxiliary power circuit 250 so that the voltage Vout matches the drive signal DRV (i). Control. With the operation of the driver 230, the voltage Vout follows the voltage of the drive signal DRV (i).
The auxiliary power supply circuit 250 generates the voltages VH / 6, 2VH / 6, 3VH / 6, 4VH / 6, and 5VH / 6 from the predetermined potential VDD generated by the rectifier circuit 57 and supplies the generated voltages to the driver 230. Is a voltage Vout that follows the voltage of the drive signal DRV (i) using a predetermined potential VDD, a reference potential GND, and voltages VH / 6, 2VH / 6, 3VH / 6, 4VH / 6, and 5VH / 6. Is supplied to the piezoelectric element 240.
The voltage VH / 6 is supplied from the auxiliary power supply circuit 250 to the driver 230 via the power supply wiring 511. Similarly, the voltages 2VH / 6, 3VH / 6, 4VH / 6, and 5VH / 6 are supplied to the power supply wiring 512, 513, 514, and 515. As described above, the auxiliary power supply circuit 250 functions as a charge supply source.

  When the voltages VH / 6, 2VH / 6,... Are the first voltage, the second voltage,..., The power wirings 511, 512,... Are the first signal path, the second signal path,. It is equivalent to. That is, the driver 230 functions as a connection path selection unit that electrically connects the piezoelectric element 240 and the auxiliary power supply circuit 250 using the first signal path, the second signal path,.

  By configuring as described above, charging or discharging of the piezoelectric element 240 is performed by electrically connecting the piezoelectric element to the first signal path, the second signal path,. Since the connection is defined in consideration of not only the voltage of the drive signal DRV (i) but also the holding voltage of the piezoelectric element 240, the piezoelectric element 240 can be controlled more precisely. In addition, since charging and discharging of the piezoelectric element 240 proceed in stages, energy efficiency can be further increased as compared with the conventional configuration in which charging and discharging progress rapidly. Further, since a large current is not switched unlike a class D amplifier, generation of EMI can be suppressed.

<< Third application example >>
In order to avoid duplication of description, description of the common points between the above-described embodiment of the present invention and the third application example will be omitted, and only differences will be described. In the embodiment described above, the high frequency power supply unit 5 outputs the differential first high frequency voltage signal and the second high frequency voltage signal to the power supply path and the discharge path. In the printer 1 according to the third application example, the high-frequency signal generation unit 5-1 of the high-frequency power supply unit 5 generates the original drive signal ODRV, and the high-frequency power supply unit 5 receives the differential first original drive signal ODRV1 and The second original drive signal ODRV2 is output to the power supply path and the discharge path. That is, in the third application example, the high frequency power supply unit 5 that is a power supply source also functions as an original drive signal supply source.
Here, since the first original drive signal ODRV1 and the second original drive signal ODRV2 are AC signals, the resonance frequencies of the transmission-side resonance circuit 5-2 and the reception-side resonance circuit 55 are set to the basic frequency of the original drive signal ODRV. As a result, the differential first original drive signal ODRV1 and second original drive signal ODRV2 can be transmitted from the high frequency power supply unit 5 to the head unit 40.
FIG. 19 is a diagram illustrating a system configuration of the power receiving circuit 59 and the head driving circuit 61 in the third application example. As shown in the figure, the power receiving circuit 59 rectifies the first original drive signal ODRV1 and the second original drive signal ODRV2 input via the carriage-side first flat plate 91C and the carriage-side second flat plate 92C by the rectifier circuit 57. Then, the power supply voltage of the head driving circuit 61 is generated and supplied to the head driving circuit 61.
Further, the first original drive signal ODRV 1 and the second original drive signal ODRV 2 are supplied to the original drive signal acquisition unit 64. The original drive signal acquisition unit 64 converts the first original drive signal ODRV1 and the second original drive signal ODRV2 from the differential format to the single end format and adjusts the amplitude to generate the original drive signal ODRV.
With this configuration, since the path for transmitting the original drive signal ODRV and the path for transmitting power can be used together, it is not necessary to transmit the parameters for generating the original drive signal to the head unit 40 side. There is no need to generate a signal by the head drive circuit 61. Accordingly, since it is not necessary to provide the constituent members related to the processing that becomes unnecessary, the configuration of the head drive circuit 61 can be simplified.

<< 4th application example >>
In order to avoid duplication of description, description of the common points between the above-described embodiment of the present invention and the fourth application example will be omitted, and only differences will be described. In the printer 1 according to the fourth application example, the power receiving circuit 59 reduces a frequency component equal to or higher than a predetermined frequency from the high-frequency voltage signal input via the carriage-side first flat plate 91C and the carriage-side second flat plate 92C. A signal processing unit (low-pass filter). As a result, “noise caused by electrostatic discharge (ESD)” included in a frequency component equal to or higher than a predetermined frequency can be reduced, and malfunction of an electric circuit caused by ESD can be suppressed.

The above-described embodiments are for facilitating understanding of the present invention, and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.
In each of the above-described embodiments, a method using radio waves is used as a method for wirelessly transmitting a control signal such as the print signal PRT from the controller 10 to the head drive circuit 61 of the carriage 32. It is not limited. For example, the control signal may be transmitted optically. That is, the laser irradiation unit may be provided on the controller 10 side, the photoelectric conversion unit may be provided on the carriage 32 side, and the control signal may be transmitted as laser light from the laser irradiation unit to the photoelectric conversion unit. In this case, the laser beam from the laser irradiation unit is irradiated in parallel with the carriage movement direction. Accordingly, the laser irradiation unit can irradiate the photoelectric conversion unit with laser light over the entire range of the reciprocation path of the carriage 32.
In the above-described embodiment, the piezoelectric effect method using the piezoelectric element is exemplified as the ink discharge method. However, the present invention is not limited to this. A thermal jet method may be used.

<< 5th application example >>
The arrangement of the housing-side first flat plate 91H, the carriage-side first flat plate 91C, the housing-side second flat plate 92H, and the carriage-side second flat plate 92C is not limited to the above-described example. In the example described below, the housing-side first flat plate 91H and the carriage-side first flat plate 91C are arranged so as not to sandwich the path of the paper S that is transported by the transport unit 20 (hereinafter referred to as a transport path), and The housing side second flat plate 92H and the carriage side second flat plate 92C are arranged.
In the example shown in FIG. 20, in the casing 3, the casing-side first flat plate 91 </ b> H and the casing-side second flat plate 92 </ b> H are provided in the same plane (horizontally) on the top plate 3 t facing the upper surface of the carriage 32. Yes.
In the carriage 32, a carriage-side first flat plate 91C is provided near the upper surface of the carriage 32 so as to face the housing-side first flat plate 91H, and the carriage-side second flat plate 92C is faced to the housing-side second flat plate 92H. Is provided. Here, the carriage-side first flat plate 91C and the carriage-side second flat plate 92C are provided in the same plane (horizontally).
Here, the housing-side first flat plate 91H, the housing-side second flat plate 92H, the carriage-side first flat plate 91C, and the carriage-side second flat plate 92C are provided substantially parallel to the nozzle surface 41a.

  According to the arrangement mode shown in FIG. 20, the carriage-side first flat plate 91C and the carriage-side second flat plate 92C are arranged in the same plane. Become. Even if the carriage-side first flat plate 91C and the carriage-side second flat plate 92C are electric field-coupled, a coupling capacity that does not substantially adversely affect the power transmission efficiency (power gain) is generated between the two. Therefore, the carriage-side first flat plate 91C and the carriage-side second flat plate 92C are electrically coupled to form a coupling capacitance, thereby forming a power transmission system different from the originally intended one. It is suppressed that efficiency of this falls.

In the example shown in FIG. 21, the housing side first flat plate 91 </ b> H and the housing side second flat plate are placed on the back plate 3 b facing the back surface of the carriage 32 (the end surface in the direction opposite to the transport direction shown in the figure) in the housing 3. 92H is provided in the same plane.
In the carriage 32, a carriage-side first flat plate 91C is provided in the vicinity of the rear surface of the carriage 32 so as to face the housing-side first flat plate 91H, and the carriage-side second flat plate 92C is provided so as to face the housing-side second flat plate 92H. Is provided. Here, the carriage-side first flat plate 91C and the carriage-side second flat plate 92C are provided in the same plane.
Here, the housing-side first flat plate 91H, the housing-side second flat plate 92H, the carriage-side first flat plate 91C, and the carriage-side second flat plate 92C are provided substantially perpendicular to the nozzle surface 41a.

According to the arrangement shown in FIG. 21, the carriage-side first flat plate 91C and the carriage-side second flat plate 92C are arranged in the same plane. It becomes difficult. Even if the carriage-side first flat plate 91C and the carriage-side second flat plate 92C are electric field-coupled, a coupling capacity that does not substantially adversely affect the power transmission efficiency (power gain) is generated between the two. Therefore, the carriage-side first flat plate 91C and the carriage-side second flat plate 92C are electrically coupled to form a coupling capacitance, thereby forming a power transmission system different from the originally intended one. It is suppressed that efficiency of this falls.
Furthermore, since the carriage-side first flat plate 91C and the carriage-side second flat plate 92C are arranged in the same plane, the distance between the two can be shortened as compared with the arrangement mode in which both face each other. An increase in the size of the carriage 32 caused by arranging them can be avoided.

DESCRIPTION OF SYMBOLS 1 ... Printer, 10 ... Controller, 11 ... Interface part, 110 ... Computer, 13 ... Memory, 14 ... Unit control circuit, 17 ... Transmitter, 20 ... Conveyance unit, 21 ... Paper feed roller, 22 ... Conveyance motor, 23 ... Conveying roller, 24... Platen, 25 .. Discharge roller, 3 .. Housing, 300... First part, 301, 301-1, 301-2... Two-terminal pair circuit, 302. Carriage motor 34a 1st pulley 34b 2nd pulley 35 Timing belt 36 Guide rail 37 Receiver 3a Mechanical frame 40 Head unit 41 Head 411 Nozzle array DESCRIPTION OF SYMBOLS 5 ... High frequency power supply unit, 5-1 ... High frequency signal generation part, 5-2 ... Transmission side resonance circuit, 50 ... Detector group, 51 ... Detection sensor, 52 ... Linear encoder, 53 ... Rotary encoder, 54G ... Terminal, 54P ... Terminal, 55 ... Receiving side resonance circuit, 57 ... Rectifier circuit, 58G, 58P ... Terminal, 59 ... Power receiving circuit, 61 ... Head drive Circuit 62G ... Ground terminal 62P ... Power supply terminal 63 ... Original drive signal generator 64 ... Original drive signal acquisition unit 65 ... Drive signal shaping unit 67 ... Converter 91H ... Case side first flat plate 91C Carriage side first flat plate, 92H ... Housing side second flat plate, 92C ... Carriage side second flat plate, C1, C3 ... Primary side capacitive element, C2, C4 ... Secondary side capacitive element, _CM ... Coupling capacitance, L1, L3 ... primary inductance element, L2, L4 ... secondary inductance element, R ... impedance of coupling capacitance, RL ... load, Rs ... internal resistance, S ... paper, TE DESCRIPTION OF SYMBOLS 1 ... Output terminal, TE2 ... Output terminal, Vs ... Power supply.

Claims (12)

A head unit for discharging liquid;
A carriage mounted with the head unit and movable;
A power supply source for supplying power for discharging the liquid from the head unit;
A housing in which the power supply source is installed;
A case-side conductor installed in the case;
A carriage-side conductor installed on the carriage,
The electric power is transmitted from the power supply source to the carriage via a coupling capacitor formed by electric field coupling between the housing-side conductor and the carriage-side conductor.
A liquid discharge apparatus characterized by that. The housing-side conductor and the carriage-side conductor have a substantially flat plate shape,
The carriage-side conductor faces at least a part of the housing-side conductor during a period in which the carriage is moving.
The liquid ejection apparatus according to claim 1, wherein A transmission-side resonance circuit that is installed in the case and is electrically connected to the case-side conductor and resonates at a first frequency;
A receiving-side resonance circuit that is installed in the carriage and is electrically connected to the carriage-side conductor and resonates at a second frequency;
Including
The first frequency and the second frequency substantially coincide with each other,
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. The coupling capacitor is provided in a power supply path that supplies power to the carriage from the power supply source installed in the housing.
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. The coupling capacitance is provided in a discharge path for discharging from the carriage to the power supply source installed in the housing.
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. The head unit is
A nozzle for discharging the liquid;
A pressure chamber communicating with the nozzle;
A piezoelectric element provided for each pressure chamber,
The piezoelectric element is driven by the power.
The liquid discharge apparatus according to claim 1, wherein the liquid discharge apparatus is a liquid discharge apparatus. The head unit is
An original drive signal acquisition unit for acquiring an original drive signal for driving the piezoelectric element;
A class D amplifier that amplifies the original drive signal and supplies the amplified signal to the piezoelectric element,
The liquid ejecting apparatus according to claim 6. The head unit is
Auxiliary power,
A first signal path to which a first voltage is applied by the auxiliary power source;
A second signal path to which a second voltage higher than the first voltage is applied by the auxiliary power source;
A signal generator for generating a drive signal for driving the piezoelectric element;
Connection path selection for electrically connecting the piezoelectric element and the auxiliary power source using the first signal path or the second signal path according to the voltage of the driving signal and the holding voltage of the piezoelectric element. Including
The liquid ejecting apparatus according to claim 6. The power supply source supplies the power as a drive signal for driving the piezoelectric element to the carriage via the coupling capacitor,
The carriage is
A rectifying unit that rectifies the drive signal to generate a power supply voltage, and applies the power supply voltage to the head unit;
A drive unit to which the power supply voltage is applied and drives the piezoelectric element based on the drive signal;
The liquid ejecting apparatus according to claim 6. The power supply source supplies the power by supplying a voltage signal,
The carriage is provided with a signal processing unit that reduces a frequency component equal to or higher than a predetermined frequency in the voltage signal.
The liquid ejection apparatus according to claim 1, wherein the liquid ejection apparatus is a liquid ejection apparatus according to claim 1. A signal generation unit that is provided in the housing and generates a control signal for controlling the driving of the piezoelectric element;
A transmission unit provided in the housing and wirelessly transmitting the control signal to the head unit;
A receiver provided on the carriage for receiving the control signal transmitted wirelessly;
The liquid ejection apparatus according to claim 6, further comprising: A head unit for discharging liquid;
A carriage mounted with the head unit and movable;
A power supply source for supplying power for discharging the liquid from the head unit;
A housing in which the power supply source is installed;
A case-side conductor installed in the case;
A method of driving a liquid ejection apparatus comprising a carriage-side conductor installed on the carriage,
Transmitting the power from the power supply source to the carriage via a coupling capacitance formed by electric field coupling between the housing-side conductor and the carriage-side conductor;
The head unit ejecting the liquid using the transmitted power;
A method for driving a liquid ejection apparatus, comprising:

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