JP2015174324A - Liquid ejection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejection device in which electrical power can be supplied from a body part to a carriage without using an FFC (Flexible Flat Cable), by using a simple and highly safe configuration.SOLUTION: The liquid ejection device includes: a first pulley 34a; a second pulley; and a timing belt which is trained over the pulleys and to which a carriage is connected. The timing belt includes: a portion of a charging path for charging a piezoelectric element from a circuit board; and a portion of a discharging path for discharging from the piezoelectric element to the circuit board. The first pulley 34a includes: a first inclined surface s1 whose distance from its outer peripheral surface to a rotary shaft ar changes from one width-direction end side toward a width-direction central part side; and a second inclined surface s2 whose distance from its outer peripheral surface to the rotary shaft ar changes from the other end side toward the central part side in the width direction. The first inclined surface s1 includes a first member 201v for transmitting electrical power to the charging path of the timing belt. The second inclined surface s2 includes a second member 201g which is electrically connected to the discharging path of the timing belt.

Description

  The present invention relates to a liquid ejection apparatus such as a printer.

A printer having a configuration in which a drive control unit that drives a printer head (hereinafter referred to as a head) is mounted on a carriage together with the head is known. Hereinafter, in the printer having such a mode, a portion excluding the carriage and the mounted product is referred to as a “main body”.
Since the printer having the above-described configuration needs to transmit a print signal from the main body side to the carriage side, the main body portion and the carriage are referred to as a flexible flat cable (hereinafter referred to as FFC (Flexible Flat Cable)) having high flexibility. ). This FFC is also used to supply power from the power supply unit of the main body to the drive control unit of the carriage.
Here, since the carriage is a member that moves in the main scanning direction, for example, the FFC tends to be a physical obstacle in 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

Power is calculated by the product of voltage and current. To transmit power, a power supply path that feeds current from the power source that generates power to the load, and a discharge that returns current from the load to the power source. A route is required. When the printer uses a configuration that uses a piezoelectric element to eject ink from the head, the piezoelectric element is an element that is displaced by charging and discharging. Therefore, the power supply path to the head drive control unit is connected to the piezoelectric element. It is also a charging route.
Since the timing belt of the liquid ejection device disclosed in Patent Document 1 described above is a single conductor made of a conductive material, it functions only as one of a power supply path and a discharge path. Therefore, it is necessary to provide another conductive path separately. Actually, Patent Document 1 proposes to use a guide rail or the like that supports the carriage as a conductive path.
When using a timing belt made of a conductive material as disclosed in Patent Document 1, if foreign matter such as misted ink adheres to the timing belt that is energized, there is a risk of heat generation due to a short circuit. There is. 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. And it is desirable to reduce the possibility of these events occurring.
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a liquid ejecting apparatus that can supply power from a main body to a carriage without using an FFC with a simple configuration.

In order to solve the above-described problems, an aspect of the liquid ejection device according to the present invention includes a piezoelectric element that is displaced by charging and discharging, a liquid that is filled therein, and the internal pressure that is generated by the displacement of the piezoelectric element. A head unit comprising: a cavity that increases and decreases; a nozzle that communicates with the cavity and discharges the liquid as droplets by increasing and decreasing the pressure in the cavity; a carriage on which the head unit is installed; and the piezoelectric element A power source that supplies power for charging the element; a circuit board on which the power source is disposed; a first pulley; a second pulley; the first pulley; and the second pulley; A belt to which a carriage is connected, and the belt includes a part of a charging path for charging the piezoelectric element from the circuit board; A part of a discharge path for discharging to the road substrate, and the first pulley has an outer peripheral surface on which the belt is hung, from one end side in the width direction toward the center side, A second inclined surface whose distance from the rotation axis of the first pulley changes, and a distance from the rotation axis of the first pulley that changes from the other end side in the width direction toward the center side. An inclined surface, wherein the first inclined surface includes a first member that transmits the power to the charging path of the belt, and the second inclined surface is electrically connected to the discharge path of the belt. The second member is provided.
According to this aspect, the belt can be provided with a charging path and a charging path, and power transmission by the belt becomes possible. Therefore, in the liquid ejection device, power can be supplied from the main body side to the carriage-side head unit without using, for example, FFC. Further, a simpler configuration is realized as compared with the case where the belt functions as only one of the charging path and the discharging path.
Furthermore, since the outer peripheral surface on which the belt is hung among the first pulleys includes the first inclined surface and the second inclined surface, when the belt is about to shift in the thickness direction of the first pulley, the belt and the first pulley Therefore, the belt position shift in the thickness direction of the first pulley (the width direction of the outer peripheral surface) is suppressed. Therefore, a short circuit due to contact between the charging path and the discharging path is 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 first pulley has an electrical resistivity lower than that of the first member and the second member. 3 member is provided, The said 3rd member is provided between the said 1st member and the said 2nd member, It is characterized by the above-mentioned.
According to this aspect, between the first member constituting the charging path in the first pulley and the second member constituting the discharging path, the third member having a lower electrical resistivity than the first member is arranged to conduct It is possible to appropriately prevent current from flowing outside the path.

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 distance between the first member and the one end is shorter than the distance from the center. The second member is characterized in that the distance from the other end is shorter than the distance from the center.
According to this aspect, since the distance between the charging path and the discharging path does not become too short, a short circuit due to the contact is less likely to occur.

Another aspect of the liquid ejection apparatus according to the present invention is the above-described aspect of the liquid ejection apparatus, wherein the first inclined surface rotates the first pulley from the one end side toward the central side. The distance from the shaft decreases, and the second inclined surface decreases in distance from the rotation axis of the first pulley from the other end portion side toward the central portion side. The distance between the inclined surface and the rotation axis is substantially the same as the distance between the second inclined surface and the rotation axis.
According to this aspect, since the outer peripheral surface of the first pulley has a substantially V-shaped cross section, the belt hung on the outer peripheral surface is less likely to meander on the outer peripheral surface of the first pulley.

Another aspect of the liquid ejection apparatus according to the present invention is the above-described aspect of the liquid ejection apparatus, wherein the first member or the second member is provided in a groove formed on an outer peripheral surface of the first pulley. The charging path or the discharging path in the belt is formed in a protruding shape that is inserted into the groove.
According to this aspect, since the charging path or discharging path of the belt formed in the protruding shape is inserted into the groove portion formed on the outer peripheral surface of the first pulley, the belt hung on the outer peripheral surface is It becomes difficult to meander on the outer peripheral surface of the pulley.

One aspect of the driving method of the liquid ejection apparatus according to the present invention includes a piezoelectric element that is displaced by charging and discharging, a cavity that is filled with liquid, and the internal pressure is increased or decreased by the displacement of the piezoelectric element. A head unit that communicates with the cavity and discharges the liquid as droplets by increasing or decreasing the pressure in the cavity; a carriage on which the head unit is installed; and charging the piezoelectric element A power source for supplying power; a circuit board on which the power source is arranged; a first pulley; a second pulley; the first pulley and the second pulley; and the carriage being connected; and , At least part of a charging path for charging the piezoelectric element from the circuit board, and a small number of discharging paths for discharging the piezoelectric element to the circuit board. A belt including a part of the first pulley, and the first pulley is provided on an outer peripheral surface of the first pulley on which the belt is hung, from one end side to the center side in the width direction of the outer peripheral surface. The first inclined surface whose distance from the rotation axis changes, and the first pulley is provided on the outer peripheral surface, and from the other end side in the width direction of the outer peripheral surface toward the central portion side, the first A liquid ejection device driving method comprising: a second inclined surface that changes a distance from a rotation axis of the pulley; and a conductive first member provided on the first inclined surface of the first pulley. Supplying the electric power to the charging path in the belt to charge the piezoelectric element, and from the discharging path in the belt through the second member having conductivity provided on the second inclined surface. From the piezoelectric element A step of performing a discharge in road substrate, by the piezoelectric element is displaced by said discharge and the charge, and having the steps of: discharging the liquid from the nozzle as droplets.
According to this aspect, the belt can be provided with a charging path and a charging path, and power transmission by the belt becomes possible. Therefore, in the liquid ejection device, power can be supplied from the main body side to the carriage-side head unit without using, for example, FFC. Further, a simpler configuration is realized as compared with the case where the belt functions as only one of the charging path and the discharging path.
Furthermore, since the outer peripheral surface on which the belt is hung among the first pulleys includes the first inclined surface and the second inclined surface, when the belt is about to shift in the thickness direction of the first pulley, the belt and the first pulley Therefore, the belt position shift in the thickness direction of the first pulley (the width direction of the outer peripheral surface) is suppressed. Therefore, a short circuit due to contact between the charging path and the discharging path is suppressed.

FIG. 2 is a block diagram illustrating a system configuration of the printer. FIG. 3 is a perspective view illustrating an internal configuration of the printer. FIG. 3 is a side sectional view of the printer shown in FIG. 2. The figure which shows the arrangement | sequence of the nozzle in a head. FIG. 3 is an explanatory diagram of a head driving circuit included in the head unit. The figure which shows the input-output relationship of an original drive signal generation part. The figure which shows an example of the waveform of the original signal ODRV, the print signal PRT (i), and the drive signal DRV (i). FIG. 4 is a schematic diagram showing an aspect of power supply from a main body side (power supply unit) to a carriage side (head drive circuit). Sectional drawing of a timing belt. The figure which shows a part of cross section which cut | disconnected the 1st pulley with the plane containing a rotating shaft. The figure which shows a part of cross section which cut | disconnected the 2nd pulley by the plane containing a rotating shaft. Sectional drawing of the timing belt in a modification. The figure which shows a part of cross section which cut | disconnected the 1st pulley in the modification in the plane containing a rotating shaft.

  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 includes a housing 3, a power supply unit 5, a controller 10, a transport unit 20, a carriage 32, a head unit 40, and a detector group 50. The printer 1 is used by connecting to a computer 110 that is an external device, for example.
That is, 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. 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 power supply unit 5 is fixed to the housing 3. The power supply unit 5 is connected to a household AC outlet or the like via an electric cord or the like, thereby functioning as a DC power source of 42 V or the like and supplies power to each part. The power supply unit 5 includes a 42V positive terminal as an output terminal for power supply, and a ground terminal that is electrically grounded via the mechanical frame 3a.

Note that the output terminal included in the power supply unit 5 is not necessarily a positive electrode terminal, and may be a negative electrode terminal that outputs a power supply signal whose level is a negative potential. That is, the power supply unit 5 includes a first power supply signal whose level is a predetermined potential (for example, power supply potential (VDD) level) and a second power supply whose level is a reference potential (for example, ground (GND) level) different from the predetermined potential. It suffices to have an output terminal for outputting a signal. The power supply unit 5 functions as a power source that supplies power for discharging liquid from the nozzles of the head unit 40.
In this embodiment, a piezoelectric element is used to eject a liquid (ink droplet) from the nozzle of the head unit 40. Since the piezoelectric element is an element that is displaced by charging and discharging, the head unit 40 (head driving circuit 61) is used. ) Is also a charging path to the piezoelectric element.

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 supply unit 5 is electrically connected to the load via the power supply path and the discharge path, and the power supply unit 5 applies a power supply voltage to the power supply path and the discharge path. More specifically, by supplying a first power supply signal to the power supply path and supplying a second power supply signal to the discharge path, a power supply voltage given as a potential difference between the first power supply signal and the second power supply signal is supplied to the power supply path and Applied to 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 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 at the time of printing. As shown in FIGS. 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 to be printed 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 printing start position, at least some of the nozzles 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 and a receiver 37.
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. The carriage 32 is supported and guided by the guide rail 36, and reciprocates in the carriage movement direction shown in FIG.

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 detailed configuration of the timing belt 35 will be described later with reference to FIG.

  The receiver 37 receives a signal wirelessly transmitted from the transmitter 17 of the controller 10 and supplies the signal to the head drive circuit 61 of the head unit 40. Specifically, the signal received by the receiver 37 is a control signal for driving the head 41 of the head unit 40 such as a print signal PRT and an original signal generation parameter (described later).

The head unit 40 includes a head 41 for ejecting ink droplets onto a sheet (recording medium) S, and a head drive circuit 61 (see FIG. 5) for driving the head 41 to eject ink droplets from the nozzles N of the head 41. And is mounted on the carriage 32.
The head 41 includes a piezoelectric element that is displaced by charging and discharging, a cavity, and a nozzle. The cavity is filled with liquid (ink), and the internal pressure is increased or decreased by the displacement of the piezoelectric element. The nozzle communicates with the cavity, and ejects liquid (ink) inside the cavity as droplets by increasing or decreasing the pressure in the cavity.
A plurality of nozzles N are provided on the lower surface 41a of the head 41. Each nozzle N has an ink chamber containing ink, and a piezoelectric element as a drive element for discharging ink droplets by changing the capacity of the ink chamber. Is provided. The head driving circuit 61 drives the piezoelectric element based on the print signal PRT and the like, thereby ejecting ink droplets.

  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 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 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.

  FIG. 4 is a diagram illustrating an arrangement of nozzles 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 P (for example, 180 dpi) along the transport direction of the paper S. The nozzle rows 411 are arranged in parallel to each other with an interval in the carriage movement direction.

FIG. 5 is an explanatory diagram of the head drive circuit 61 provided in the head unit 40. In the drawing, members surrounded by a two-dot chain line are members included in the head drive circuit 61. The head drive circuit 61 is, for example, a circuit board 61 a that drives and controls each part of the head unit 40, and is arranged in the carriage 32 and includes an original drive signal generation unit 63 and a drive signal shaping unit 65. In addition, all are comprised by the electrical circuit, for example.
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). The piezo element is driven for each nozzle. 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 having a predetermined time width is applied between the electrodes provided at both ends of the piezoelectric element included in each nozzle, the piezoelectric element expands in accordance with 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 piezo element, and the ink amount corresponding to the contraction is ejected from the nozzles # 1 to # 180 of the respective colors as ink droplets.
As shown in FIG. 5, the first pulley 34a, the second pulley 34b, and the timing belt 35 also function as a power supply system for supplying power to the head drive circuit 61 (see FIG. 5) mounted on the carriage 32. Detailed configurations of these members will be described later.

  As shown in FIG. 6, the original drive signal generation unit 63 receives an original signal generation parameter that defines the waveform shape of the original signal ODRV. Based on this original signal generation parameter, the original drive signal generator 63 generates an original signal ODRV that is used in common by the nozzles # 1 to #n. Here, the original signal ODRV has two pulses of a first pulse W1 and a second pulse W2, as shown in FIG. It is a signal containing.

On the other hand, as shown in FIG. 6, the drive signal shaping unit 65 receives the original 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 signal ODRV for each nozzle (i) based on the print signal PRT (i) corresponding to each nozzle (i). For example, as shown in FIG. 7, when the print signal PRT (i) is a 2-bit signal “00”, both pulses W1 and W2 of the original signal ODRV are blocked, and the print signal PRT (i) In the case of “01”, only the pulse W1 is cut off and the pulse W2 is allowed to pass. In the case where the print signal PRT (i) is “10”, only the pulse W2 is cut off and the pulse W1 is allowed to pass. When the print signal PRT (i) is “11”, both pulses W1 and W2 are passed.
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 piezo element of each nozzle (i) is driven based on the drive signal DRV (i) from the drive signal shaping unit 65 to eject ink droplets.

Hereinafter, a power supply system to the head drive circuit 61 will be described. The head drive circuit 61 is configured by, for example, an electric circuit and operates with supplied power.
A circuit board of the head drive circuit 61 is provided on the carriage 32. In the conventional printer, the power supply unit on the main body side and the circuit board on the carriage side are connected by FFC, and power is supplied from the power supply unit to the circuit board 61a via this FFC. In a conventional printer, the FFC supplies control signals and the like in addition to electric power from the main body side (controller) to the carriage side (head drive circuit).
On the other hand, the printer 1 according to the present embodiment does not use the FFC by supplying power from the main body side (power supply unit 5) to the carriage 32 side (head drive circuit 61) in the manner described below.

FIG. 8 is a schematic diagram showing an aspect of power supply from the main body side (power supply unit 5) to the carriage 32 side (head drive circuit 61). FIG. 9 is a view showing a cross section of the timing belt 35 cut in the thickness direction. FIG. 10 is a view showing a part (one side of the shaft member 229 as a boundary) of the first pulley 34a cut along a plane including a rotation center axis (hereinafter referred to as “rotation axis”).
In the printer 1 according to the present embodiment, the first pulley 34 a, the second pulley 34 b, and the timing belt 35 associated with the movement of the carriage 32 are used in combination as a power supply system to the head drive circuit 61.

As shown in FIGS. 2 and 8, one pulley (the first pulley 34 a in this example) is provided at one end of the reciprocating path of the carriage 32. The other pulley (second pulley 34b in this example) is concentrically fixed to a shaft member 229 of the carriage motor 33 provided at the other end of the reciprocating path.
In this example, for convenience of explanation, the second pulley 34 b is fixed to the drive rotation shaft 33 b of the carriage motor 33. However, the first pulley 34 a may be fixed to the drive rotation shaft 33 b of the carriage motor 33. In addition, the carriage motor 33 is provided for both the first pulley 34a and the second pulley 34b to fix the drive rotation shaft 33b, and the carriage motor 33 is appropriately switched so as to drive one of the pulleys. Also good.

  An endless timing belt 35 is wound around the pair of pulleys 34a and 34b, and a carriage 32 is connected (fixed) to a part of the timing belt 35 via a connecting portion. The connecting portions are, for example, a pair of gripping members fixed on the carriage 32 side. When the gripping members sandwich a part of the timing belt 35, the timing belt 35 and the carriage 32 are physically movable so as not to move relative to each other. It is connected to. Therefore, the driving force of the carriage motor 33 is transmitted to the carriage 32 via the timing belt 35, and thereby the carriage 32 is reciprocated.

The timing belt 35 is made of a so-called insulating material (non-conductive material) and includes a power supply member 101v and a discharge member 101g, which are conductive portions provided apart from each other as shown in FIG.
Here, one side (indicated by reference numeral 35-1 in FIG. 9) with the substantially central position C in the width direction of the timing belt 35 as a boundary is referred to as a “first region” and the other (reference numeral 35- in FIG. 9). 2) is referred to as “second region”. In addition, the surface of the timing belt 35 that contacts the first pulley 34a and the second pulley 34b (surfaces denoted by reference numerals B1 and B2 in FIG. 9) is referred to as a “back surface”.

In the first region 35-1 of the timing belt 35, the back surface B <b> 1 is formed so that the thickness of the timing belt 35 becomes thinner from the substantially central position C in the width direction of the timing belt 35 toward the end side. Yes. Similarly, in the second region 35-2 of the timing belt 35, the back surface B2 is so thin that the thickness of the timing belt 35 becomes thinner from the substantially central position C in the width direction of the timing belt 35 toward the end side. Is formed.
More specifically, as shown in FIG. 9, the back surfaces B1 and B2 are formed as surfaces inclined by an angle θ with respect to the axial direction ad related to the rotation axes of the first pulley 34a / second pulley 34b.

Thus, by forming the back surfaces B1 and B2 of the timing belt 35 as inclined surfaces, the back surface B of the timing belt 35 with respect to the outer peripheral surfaces of the first pulley 34a and the second pulley 34b that are similarly formed as inclined surfaces. Can properly contact (preferably abut).
The power supply member 101v is provided along the longitudinal direction of the timing belt 35 on the back surface B1 which is an inclined surface in the first region 35-1. Similarly, the discharge member 101g is provided along the longitudinal direction of the timing belt 35 on the back surface B2, which is an inclined surface in the second region 35-2. Specifically, the power supply member 101v and the discharge member 101g are formed by, for example, aluminum vapor deposition.

In the present embodiment, the power supply member 101v is used as a part of a power supply path (path of the power supply potential VDD) for supplying the first power signal to the head unit 40, and the discharge member 101g is a discharge path (from the head unit 40). It is used as a part of the path of the reference potential GND. That is, in the present embodiment, the timing belt 35 includes two power supply signal paths.
That is, the power supply member 101v constitutes a part of a path for supplying the first power supply signal whose level is the power supply potential VDD to the head unit 40. The discharge member 101g constitutes a part of a path for supplying the head unit 40 with the second power supply signal whose level is the reference potential GND.

Here, the timing belt 35 itself is made of a material having a higher electrical resistivity (for example, insulating or non-conductive) than any of the power supply member 101v and the discharge member 101g as described above.
Thus, since the timing belt 35 itself is made of an insulating or non-conductive material, the safety is greatly increased as compared with the case where the entire timing belt 35 is made of a conductive material.
Further, the timing belt 35 has a tooth-like portion 99 (for power transmission) that meshes with a tooth-like portion 199 (projection for power transmission) formed on the outer peripheral surfaces of the first pulley 34a and the second pulley 34b. Grooves) are formed. The tooth-like portion 99 is also made of an insulating or non-conductive material like the timing belt 35.

  Here, the surface area of the portion where the power supply member 101v is exposed (hereinafter referred to as the first conductive exposed area) and the surface area of the portion where the discharge member 101g is exposed (hereinafter referred to as the second conductive exposed area) are. The surface area of the portion where the timing belt 35 is exposed (hereinafter, referred to as a non-conductive area) is preferably smaller. This further reduces the risk of short-circuiting due to leakage from the power supply member 101v and the discharge member 101g, foreign matter adhesion thereto, and the like. Furthermore, the sum area of the first conductive exposed area and the second conductive exposed area is preferably smaller than the non-conductive area.

As shown in FIG. 10, the first pulley 34a is a first pulley provided with a power feeding path on one side with a substantially central position C in the width direction of the outer peripheral surface (that is, the thickness direction of the first pulley 34a) w. It is area | region 34a-1, and the other side is 2nd area | region 34a-2 in which the discharge path | route was provided.
In the first region 34a-1, the outer peripheral surface on which the timing belt 35 is hung is reduced in distance from the rotation axis ar from one end side in the width direction w toward the substantially central position C side as shown in FIG. The first inclined surface s1 is provided. The first inclined surface s1 is inclined by an angle θ with respect to the rotation axis ar.
Then, a portion of the first inclined surface s1 that contacts the power feeding member 101v of the timing belt 35 is provided with the first conductive member 201v without forming the tooth-like portion 199 as shown in FIG.

On the other hand, in the second region 34a-2, the outer peripheral surface on which the timing belt 35 is hung is a distance from the rotation axis ar from the other end side in the width direction w toward the substantially central position C side as shown in FIG. Is provided with a second inclined surface s2. The second inclined surface s2 is inclined by an angle θ with respect to the rotation axis ar.
Then, at the portion of the second inclined surface s2 that contacts the discharge member 101g of the timing belt 35, the second conductive member 201g is provided without forming the tooth-like portion 199 as shown in FIG.
Here, as shown in FIG. 10, an insulating member 201i is provided in a region within a predetermined range including the substantially central position C in the thickness direction of the first pulley 34a (the width direction w of the outer peripheral surface). Thereby, the first conductive member 201v in the first region 34a-1 and the second conductive member 201g in the second region 34a-2 are electrically insulated.
In other words, the insulating member 201i having a higher electrical resistivity than the first conductive member 201v and the second conductive member 201g is provided, and the first conductive member 201v and the second conductive member are provided by the insulating member 201i. The member 201g is electrically insulated.
With the above-described configuration, the first pulley 34a includes the first conductive member 201v that conducts only to the power feeding member 101v in the timing belt 35, and the second conductive member 201g that conducts only to the discharge member 101g in the timing belt 35. .

  The second pulley 34b is made of a material (for example, an insulating material) having a higher electrical resistivity than the first conductive member 201v and the second conductive member 201g, and is similar to the first pulley 34a as shown in FIG. Has a shape. That is, the second pulley 34b does not include a conductive member because it is not used as a power feeding path or a discharge path, but adopts the same shape as the first pulley 34a so as to be suitably in contact with the timing belt 35.

By the way, the timing belt 35 includes two power supply signal supply paths including the power supply member 101v and the discharge member 101g as described above. Accordingly, if the position of the timing belt 35 with respect to the first pulley 34a is shifted in the thickness direction of the first pulley 34a (the width direction w of the outer peripheral surface), the timing is applied to the first conductive member 201v of the first pulley 34a. There is a risk that not the power supply member 101v of the belt 35 but the discharge member 101g comes into contact, and the power supply path and the short-circuit path are short-circuited.
However, in the present embodiment, in view of such circumstances, the back surfaces B1 and B2 of the timing belt 35 are formed to have an angle θ with respect to the axial direction ad related to the rotation axis ar, and the first pulley The outer peripheral surface of 34a is also formed in a substantially V-shaped cross section so as to suitably contact (desirably contact) the back surfaces B1 and B2 of such timing belt 35.
As a result, when the timing belt 35 is about to shift in the thickness direction of the first pulley 34a (the width direction w of the outer peripheral surface), the back surface B1 / back surface B2 of the timing belt 35 and the first inclined surface of the first pulley 34a. Since the s1 / second inclined surface s2 is engaged in the width direction w, the positional deviation of the timing belt 35 is suppressed as compared with the case where these surfaces are formed as horizontal surfaces. Therefore, a short circuit between the power supply path and the discharge path due to the contact between the first conductive member 201v and the discharge member 101g or the contact between the second conductive member 201g and the power supply member 101v is suppressed.

  As described above, in the timing belt 35, the power supply member 101v and the discharge member 101g are provided separately from the tooth-like portion 99 (in different regions), and the first conductive member 201v and the second conductive member of the first pulley 34a are provided. By providing 201 g separately from the tooth-like portion 199 (in different areas), between the tooth-like portion 199 (projecting portion) of the first pulley 34 a and the tooth-like portion 99 (groove portion) of the timing belt 35. It is possible to reduce the influence of noise related to ESD caused by friction on a power supply signal flowing through a power supply path or a discharge path.

  By the way, the first conductive member 201v of the first pulley 34a is electrically connected to the positive terminal of the power supply unit 5 described above, and is used as a part of the power supply path to the head unit 40. Specifically, for example, a portion of the first pulley 34a from the shaft member 229 to the first conductive member 201v is made of a conductive material, and the first conductive member 201v is connected from the power supply unit 5 via the shaft member 229. Is supplied with the first power signal. As described above, the power supply member 101v of the timing belt contacts the first conductive member 201v, and the first power supply signal (electric power) is supplied from the first conductive member 201v to the power supply member 101v.

Further, the power supply terminal 62P (for example, the positive terminal) of the circuit board 61a of the head drive circuit 61 shown in FIG. 5 is connected to the carriage 32 and the timing belt 35 so as to contact the power supply member 101v in the timing belt 35. It extends to the part and is electrically connected to the power supply member 101v of the timing belt 35. As a result, the first power supply signal is supplied from the power supply member 101v to the power supply terminal 62P.
With the above-described configuration, the first power supply signal (power) whose level is the power supply potential VDD is supplied from the power supply unit 5 through the first conductive member 201v of the first pulley 34a and the power supply member 101v provided on the timing belt 35. ) Is supplied to the power supply terminal 62P.

On the other hand, the second conductive member 201g of the first pulley 34a is electrically connected to the ground terminal of the power supply unit 5 described above, and is used as a part of the discharge path from the head unit 40. Specifically, for example, a portion of the first pulley 34a from the shaft member 229 to the second conductive member 201g is made of a conductive material, and the second conductive member 201g is connected from the power supply unit 5 via the shaft member 229. In addition, a second power supply signal whose level is the reference potential GND is supplied.
The shaft member 229 may be electrically connected to the mechanical frame 3a of the housing 3, and a part of the discharge path may be configured using the second conductive member 201g, the shaft member 229, and the mechanical frame 3a.
Here, the ground terminal 62G of the head drive circuit 61 shown in FIG. 5 is extended to the connection portion between the carriage 32 and the timing belt 35 so as to come into contact with the discharge member 101g in the timing belt 35. Connected.
With the above-described configuration, the second power signal is supplied to the ground terminal 62 </ b> G of the head drive circuit 61 through the second conductive member 201 g of the first pulley 34 a and the discharge member 101 g of the timing belt 35. In other words, the discharge member 101g of the timing belt 35 and the second conductive member 201g of the first pulley 34a constitute a part of the discharge path from the head drive circuit 61.

As described above, according to one embodiment of the present invention, power can be supplied from the main body side to the carriage 32 side without using FFC. In addition, since the timing belt 35 includes a power feeding path (power feeding member 101v) and a discharge path (discharge member 101g), a desired voltage can be transmitted to the carriage 32 only by the timing belt 35. Realize. Since the material of the timing belt 35 itself is a member having a high electrical resistivity (for example, a non-conductive member), there is almost no danger even if a liquid such as ink adheres.
Further, the back surfaces B1 and B2 of the timing belt 35 are formed in a substantially V-shaped cross section having an angle θ with respect to the axial direction ad related to the rotation axis ar, and the outer peripheral surfaces of the first pulley 34a and the second pulley 34b. However, it is formed in a substantially V-shaped cross section so as to preferably contact (desirably abut) the back surfaces B1 and B2 of the timing belt 35.
Thereby, when the timing belt 35 is about to shift in the thickness direction of the first pulley 34a, the back surface B1 / back surface B2 of the timing belt 35, the first inclined surface s1 / the second inclined surface s2 of the first pulley 34a, and Therefore, the positional displacement of the timing belt 35 in the thickness direction of the first pulley 34a (the width direction w of the outer peripheral surface) is suppressed as compared with a case where these surfaces are formed as horizontal surfaces. Therefore, a short circuit due to contact between the power supply path and the discharge path (contact between the first conductive member 201v and the discharge member 101g and contact between the second conductive member 201g and the power supply member 101v) is suppressed.
In the first pulley 34a, the first conductive member 201v is preferably provided at a position where the distance from the end of the first region 34a-1 is shorter than the distance from the substantially central position C. The second conductive member 201g is preferably provided at a position where the distance from the end of the second region 34a-2 is shorter than the distance from the substantially central position C. By comprising in this way, the short circuit by the contact of an electric power feeding path and a discharge path becomes difficult to generate | occur | produce.

Of course, the second pulley 34b, which is a main driving pulley driven and rotated by the carriage motor 33, may be used as a part of the charging path and the discharging path.
The timing belt 35, the power supply member 101v, the discharge member 101g, the first pulley 34a, the first conductive member 201v, the second conductive member 201g, and the second pulley 34b are charged with the same polarity. It is preferable that it is made of a material having characteristics. As a result, even if they are charged by friction or the like, they are charged to the same polarity, so noise related to ESD is reduced, and stability of power supplied to the timing belt 35 is improved. In addition, it is preferable that the tooth-like parts 99 and 199 are insulated from the charging path and the discharging path.
If necessary, a DC-DC converter 67 is provided as in the example shown in FIG. 5, so that the voltage of the power supply unit 5 is changed to an appropriate voltage required by the head drive circuit 61 (example shown in FIG. 5). Then, power may be transformed to 3.3V).

<Modification>
Hereinafter, a modified example of the above-described embodiment will be described. In order to avoid duplication of explanation, explanation of features that are common to the embodiment will be omitted, and differences will be explained. This difference is in the shapes of the back surfaces B1 and B2 of the timing belt 35 and the shapes of the outer peripheral surfaces of the first pulley 34a and the second pulley 34b.
FIG. 12 shows a cross-sectional view of the timing belt 35 in a modified example. As shown in the figure, the timing belt 35 is formed with a power feeding member 103v having a shape protruding in the thickness direction of the timing belt 35. Similarly, the timing belt 35 is formed with a discharge member 103 g having a shape protruding in the thickness direction of the timing belt 35.
FIG. 13 shows a part of a cross section obtained by cutting the first pulley 34a according to the modification along a plane including the rotation axis. As shown in the figure, a groove portion d into which the power feeding member 103v of the timing belt 35 is inserted is formed on the outer peripheral surface of the first region 34a-1 of the first pulley 34a, and the power feeding member inserted into the groove portion d. A first conductive member 201v is provided so as to be in contact with the lower surface of 103v. Similarly, a groove portion d into which the discharge member 103g of the timing belt 35 is inserted is formed on the outer peripheral surface of the second region 34a-2 of the first pulley 34a, and the lower surface of the discharge member 103g inserted into the groove portion d A second conductive member 201g is provided so as to come into contact.
In addition, about the 2nd pulley 34b, it is preferable to comprise in the shape similar to the 1st pulley 34a.
According to the printer of this modification, when the timing belt 35 is about to shift in the thickness direction of the first pulley 34a, the power supply member 103v / discharge member 103g of the timing belt 35 and the groove portion d of the first pulley 34a Therefore, the displacement of the timing belt 35 in the thickness direction of the first pulley 34a (the width direction w of the outer peripheral surface) is more reliably suppressed.

In addition, the above-mentioned embodiment and modification are for making an understanding of this invention easy, and are not for limiting and interpreting this 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 the embodiment and the modification described above, 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. This is not a limitation. 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 embodiments and modifications, the piezoelectric effect method using a piezo element is illustrated as an ink ejection method, but the present invention is not limited to this. For example, the ink is heated and air is generated by bubbles generated in the ink. A thermal jet method of discharging from a nozzle may be used.

DESCRIPTION OF SYMBOLS 1 ... Printer, 10 ... Controller, 101g, 103g ... Discharge member, 101v, 103v ... Feeding member, 11 ... Interface part, 110 ... Computer, 13 ... Memory, 14 ... Unit control circuit, 17 ... Transmitter, 199 ... Tooth shape , 20 ... conveying unit, 201v ... first conductive member, 201g ... second conductive member, 201i ... insulating portion, 21 ... paper feeding roller, 22 ... conveying motor, 229 ... shaft member, 23 ... conveying roller, 24 ... platen , 25 ... paper discharge roller, 3 ... housing, 32 ... carriage, 33 ... carriage motor, 34a ... first pulley, 34b ... second pulley, 34a-1 ... first area, 34a-2 ... second area, 34b ... second pulley, 35 ... timing belt, 35-1 ... first region, 35-2 ... second region, 36 ... guide rail, 3 ... receiver, 3a ... mechanical frame, 40 ... head unit, 41 ... head, 411 ... nozzle array, 5 ... power supply unit, 50 ... detector group, 51 ... paper detection sensor, 52 ... linear encoder, 53 ... rotary type Encoder 61 ... head drive circuit 61a ... circuit board 62G ... ground terminal 62P ... power supply terminal 63 ... original drive signal generator 65 ... drive signal shaping unit 67 ... converter 99,199 ... toothed Part, B1, B2 ... back surface, C, C-2 ... substantially central position, s1 ... 1st inclined surface, s2 ... 2nd inclined surface, d ... groove part.

Claims (6)

A piezoelectric element that is displaced by charging and discharging;
A cavity filled with a liquid, and the pressure inside the cavity is increased or decreased by displacement of the piezoelectric element;
A head unit comprising: a nozzle that communicates with the cavity and discharges the liquid as droplets by increasing or decreasing the pressure in the cavity;
A carriage on which the head unit is installed;
A power source for supplying power for charging the piezoelectric element;
A circuit board on which the power source is disposed;
A first pulley;
A second pulley;
A belt hung on the first pulley and the second pulley and connected to the carriage;
With
The belt includes a part of a charging path for charging the piezoelectric element from the circuit board and a part of a discharging path for discharging from the piezoelectric element to the circuit board,
The first pulley is
On the outer peripheral surface on which the belt is hung, a first inclined surface in which the distance from the rotation axis of the first pulley changes from one end side in the width direction to the center side;
A second inclined surface in which the distance from the rotation axis of the first pulley changes from the other end side in the width direction toward the center side,
The first inclined surface includes a first member that transmits the electric power to the charging path of the belt,
The second inclined surface includes a second member electrically connected to the discharge path in the belt.
A liquid discharge apparatus characterized by that. The first pulley includes a third member having an electrical resistivity lower than that of the first member and the second member,
The third member is provided between the first member and the second member.
The liquid ejection apparatus according to claim 1, wherein The first member is shorter in distance from the one end than in the distance from the center.
The second member has a shorter distance from the other end than a distance from the central portion.
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. In the first inclined surface, the distance from the rotation axis of the first pulley decreases from the one end side toward the central part side,
The second inclined surface, the distance from the rotation axis of the first pulley decreases from the other end side toward the central part side,
In the central portion, a distance between the first inclined surface and the rotation axis is substantially equal to a distance between the second inclined surface and the rotation axis.
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. The first member or the second member is provided in a groove formed on an outer peripheral surface of the first pulley,
The charging path or the discharging path in the belt is formed in a protruding shape that is inserted into the groove.
The liquid ejection apparatus according to claim 1, wherein the liquid ejection apparatus is a liquid ejection apparatus according to claim 1. A piezoelectric element that is displaced by charging and discharging;
A cavity filled with a liquid, and the pressure inside the cavity is increased or decreased by displacement of the piezoelectric element;
A head unit comprising: a nozzle that communicates with the cavity and discharges the liquid as droplets by increasing or decreasing the pressure in the cavity;
A carriage on which the head unit is installed;
A power source for supplying power for charging the piezoelectric element;
A circuit board on which the power source is disposed;
A first pulley;
A second pulley;
The carriage is connected to the first pulley and the second pulley and the carriage is connected, and at least a part of a charging path for charging the piezoelectric element from the circuit board, and discharging from the piezoelectric element to the circuit board A belt including at least a part of a discharge path for performing
The first pulley is provided on the outer peripheral surface on which the belt is hung, and the distance from the rotation axis of the first pulley changes from one end side to the center side in the width direction of the outer peripheral surface. A first inclined surface;
A second inclined surface provided on the outer peripheral surface of the first pulley, the distance from the rotation axis of the first pulley changing from the other end side to the central side in the width direction of the outer peripheral surface; A method of driving a liquid ejection device comprising:
The electric power is supplied to the charging path in the belt from the first member having conductivity provided on the first inclined surface of the first pulley to charge the piezoelectric element, and the discharging path in the belt. From the piezoelectric element to the circuit board through a conductive second member provided on the second inclined surface;
Discharging the liquid as droplets from the nozzle by the piezoelectric element displaced by the charging and discharging;
A method for driving a liquid ejection apparatus, comprising:

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