JP2012206285A - Liquid discharge device - Google Patents

Abstract

An object of the present invention is to efficiently dissipate heat generated by a head control circuit to improve a heat dissipation effect.
A liquid ejection apparatus according to the present invention includes a carriage that moves in a crossing direction that intersects a transport direction in which a medium is transported, a head portion that is provided in the carriage, and includes a nozzle and a liquid that is discharged from the nozzle. A head unit having a drive element to be ejected, and a head control unit that has a switch for controlling on / off of whether or not to apply a drive signal to the drive element and controls the drive of the drive element; And a variable opening provided on one side and the other side in the intersecting direction so that the size of the opening can be changed, and the variable opening while being in contact with the head control unit. And a cavity for cooling the air that has flowed from the variable opening by moving the carriage against the metal.
[Selection] Figure 6

Description

  The present invention relates to a liquid ejection apparatus.

As an example of a liquid ejecting apparatus, an ink jet printer that performs printing by ejecting ink onto a medium such as paper is known. The ink jet printer is provided with a head unit, and the head unit includes a nozzle, a driving element corresponding to the nozzle (for example, a piezo element), and a switch that selectively applies a driving signal to the driving element. A control circuit;
(For example, Patent Document 1).

JP-A-11-300956

In such an ink jet printer, when printing is performed for a long time, on / off control of whether or not the switch in the head control circuit applies a drive signal to the drive element is frequently repeated. As a result, the temperature of the head control circuit may be excessively increased due to heat generation, which may cause a malfunction.

The present invention has been made in view of such circumstances, and an object of the present invention is to efficiently dissipate the heat generated by the head control circuit and improve the heat dissipation effect.

The main invention for solving the above problems is:
A carriage that moves in a crossing direction that intersects the transporting direction of transporting the medium;
A head portion provided on the carriage,
A nozzle, a drive element that discharges liquid from the nozzle, and a head control unit that includes a switch that performs on / off control as to whether or not to apply a drive signal to the drive element, and that controls driving of the drive element. The head,
A cavity provided along the crossing direction,
A variable opening provided to be able to change the size of the opening on one side and the other side in the crossing direction;
A cavity portion that is provided between the variable opening portions in contact with the head control portion, and that cools the air flowing from the variable opening portions by movement of the carriage against the metal portion. When,
A liquid ejecting apparatus comprising:
Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

1 is a block diagram of the overall configuration of a printer. 1 is a schematic diagram illustrating a configuration of a printer. FIG. 2A is a perspective view of the printer 1. FIG. 2B is a cross-sectional view of the printer 1. It is a block diagram of head control part HC. It is explanatory drawing explaining the timing of each signal. It is a disassembled perspective view around the head controller HC. 2 is a schematic diagram illustrating a configuration of a head unit 40 mounted on a carriage 31. FIG. It is a figure explaining the operation example of the variable opening part.

  At least the following matters will become apparent from the description of the present specification and the accompanying drawings.

That is, a carriage that moves in a crossing direction that intersects the transporting direction of transporting the medium;
A head portion provided on the carriage,
A nozzle, a drive element that discharges liquid from the nozzle, and a head control unit that includes a switch that performs on / off control as to whether or not to apply a drive signal to the drive element, and that controls driving of the drive element. The head,
A cavity provided along the crossing direction,
A variable opening provided to be able to change the size of the opening on one side and the other side in the crossing direction;
A cavity portion that is provided between the variable opening portions in contact with the head control portion, and that cools the air flowing from the variable opening portions by movement of the carriage against the metal portion. When,
A liquid ejecting apparatus comprising:
According to such a liquid ejecting apparatus, a part of the cavity is formed of a metal member, the head controller is brought into contact with the metal member, and the air flowing into the cavity is applied to the metal member. Since cooling is performed, it is possible to improve the heat dissipation effect and suppress the occurrence of malfunction of the head controller.

In addition, such a liquid ejection device,
When the variable opening located on the front side in the traveling direction of the carriage is the one side variable opening and the variable opening located on the rear side in the traveling direction of the carriage is the other side variable opening In addition,
The variable opening on the one side may have a larger opening than the variable opening on the other side.
According to such a liquid ejection device, a large amount of air is taken into the cavity from the variable opening on the front side in the traveling direction, and less air is discharged from the variable opening on the rear side in the traveling direction. The effect can be improved.

In addition, such a liquid ejection device,
The metal part may be grounded.
According to such a liquid ejecting apparatus, it is possible to suppress problems such as damage to the head controller due to static electricity and malfunctions caused by superimposing this static electricity on the drive signal as noise.

In addition, such a liquid ejection device,
The carriage is
It is guided by the guide rail and moves in the crossing direction,
The head portion is
A head case having a first side surface downstream of the guide rail in the transport direction and a second side surface downstream of the first side surface in the transport direction;
The hollow portion may be provided on the second side surface side of the head case.

According to such a liquid ejecting apparatus, by providing the cavity portion on the second side surface side, air outside the printer having a temperature lower than the air inside the printer passes through the cavity portion, so that the heat dissipation effect is further improved. Can be improved.

In the following embodiments, an inkjet printer 1 (hereinafter also referred to as “printer 1”) will be described as an example.

=== Embodiment ===
<<< Configuration Example of Printer 1 >>>
A configuration example of the printer 1 will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram of the overall configuration of the printer 1 of the present embodiment. FIG. 2A is a perspective view of the printer 1, and FIG. 2B is a cross-sectional view of the printer 1.

The printer 1 according to the present embodiment includes a transport unit 20 as an example of a transport unit, a carriage unit 30, a head unit 40 as an example of a head unit, a detector group 50, and a controller 60. The printer 1 that has received print data from the computer 110 that is an external device controls each unit (the conveyance unit 20, the carriage unit 30, and the head unit 40) by the controller 60. The controller 60 controls each unit based on the print data received from the computer 110 and prints an image on paper. The situation in the printer 1 is monitored by the detector group 50, and the detector group 50 outputs the detection result to the controller 60. The controller 60 controls each unit based on the detection result output from the detector group 50.

The transport unit 20 moves the medium S (for example, paper S) in a predetermined direction (hereinafter referred to as “transport direction”).
For the purpose of transportation). The transport unit 20 includes a paper feed roller 21, a transport motor 22 (also referred to as “PF motor”), a transport roller 23, and a platen 2.
4 and a paper discharge roller 25. The paper feed roller 21 is a roller for feeding the paper inserted into the paper insertion slot into the printer. The transport roller 23 is a roller that transports the paper S fed by the paper feed roller 21 to a printable area.
Driven by. The platen 24 supports the paper S being printed. The paper discharge roller 25 is
A roller that discharges the paper S to the outside of the printer, and is provided on the downstream side in the transport direction with respect to the printable area.

The carriage unit 30 is for moving (also referred to as “scanning”) the head in an intersecting direction (hereinafter referred to as “movement direction”) that intersects the conveyance direction. The carriage unit 30 includes a carriage 31 and a carriage motor 32 (also referred to as “CR motor”). The carriage 31 can reciprocate in the movement direction along the guide rail 33 and is driven by a carriage motor 32. Further, the carriage 31 detachably holds an ink cartridge CRG that stores ink.

The head unit 40 is for ejecting ink onto paper. Head unit 40
Comprises a head 41 having a plurality of nozzles, a head controller HC (head control circuit), and a head case 45 for housing them. Since the head 41 is provided on the carriage 31, when the carriage 31 moves in the movement direction, the head 41 also moves in the movement direction. Then, by intermittently ejecting ink while the head 41 is moving in the moving direction, dot lines (raster lines) along the moving direction are formed on the paper. The configuration of the head 41 and the details of the head controller HC will be described later.

The detector group 50 includes a linear encoder 51, a rotary encoder 52, a paper detection sensor 53, an optical sensor 54, and the like. The linear encoder 51 is
The position of the carriage 31 in the moving direction is detected. The rotary encoder 52 detects the rotation amount of the transport roller 23. The paper detection sensor 53 detects the position of the leading edge of the paper S being fed. The optical sensor 54 detects the presence or absence of the paper S by a light emitting unit and a light receiving unit attached to the carriage 31. The optical sensor 54 can detect the position of the edge of the paper S while being moved by the carriage 31, and can detect the width of the paper S. In addition, the optical sensor 54 has a leading end (an end on the downstream side in the transport direction, also referred to as an “upper end”) and a rear end (an end on the upstream side in the transport direction, and a “lower end”) depending on the situation. Can also be detected.

The controller 60 is a control unit for controlling the printer 1. The controller 60 includes an interface unit 61, a CPU 62, a memory 63, a unit control circuit 64, and a drive signal generation unit 65. The interface unit 61 transmits and receives data between the computer 110 that is an external device and the printer 1. CPU62
Is an arithmetic processing unit for controlling the entire printer. The memory 63 is the CPU 6
This is for securing an area for storing the program 2 and a work area, and has a storage element such as a RAM. The CPU 62 controls each unit via the unit control circuit 64 in accordance with a program stored in the memory 63.

The drive signal generation unit 65 generates a common drive signal COM. The common drive signal COM generated by the drive signal generation unit 65 is flexible by the flexible cable 71 having the flexibility.
It is transmitted from the main body side (controller 60) to the head side (head unit 40).

<<< About the head unit 40 >>>
<About the head controller HC>
Here, the head controller HC will be described with reference to FIGS. FIG. 3 is a block diagram of the head controller HC, and FIG. 4 is an explanatory diagram of the timing of each signal.

The head controller HC includes a first shift register 81A, a second shift register 81B, a first latch circuit 82A, a second latch circuit 82B, a decoder 83, and a control logic 84.
The switch 86 is provided. Each part excluding the control logic 84 (that is, the first shift register 81A, the second shift register 81B, the first latch circuit 82A, the second latch circuit 82B, the decoder 83, and the switch 86) is provided for each piezo element 417. Provided. The piezo element 417 is an element (driving element) that is driven to eject ink from the nozzle, and is provided for each nozzle in the head 41.

The head controller HC includes a common drive signal COM, a latch signal LAT, a change signal CH,
Pixel data SI and a clock signal CLK are input. Hereinafter, these signals will be described.

The drive signal COM is repeatedly generated every repetition period T. This repetition period T is
This is the time required for the carriage 31 to move a predetermined distance. Thus, the carriage 3
Each time 1 moves a predetermined distance, the same waveform COM is repeatedly generated from the drive signal generator 65. The common drive signal COM includes the first waveform section SS11 generated in the period T11 in the repetition period T, the second waveform section SS12 generated in the period T12, and the third waveform section SS13 generated in the period T13. And have. Here, the first waveform section SS11 is a drive pulse P.
S1 is included. Further, the second waveform section SS12 outputs the drive pulse PS2 to the third waveform section SS1.
3 each have a drive pulse PS3. Then, drive pulse PS1, drive pulse P
S2 and the drive pulse PS3 are applied to the piezo element 417 when a large dot, which will be described in detail later, is formed, and have the same waveform. Further, the driving pulse PS1 and the driving pulse P
S2 is applied to the piezo element 417 when forming a medium dot, which will be described in detail later. The drive pulse PS1 is also applied to the piezo element 417 when forming small dots, which will be described in detail later. Note that when no drive pulse is applied to the piezo element 417, ink is not ejected (dots are not formed).

This drive signal COM is input to each switch 86 provided for each piezo element 417. The switch 86 performs on / off control as to whether or not to apply the drive signal COM to the piezo element 417. By this on / off control, a part of the drive signal COM can be selectively applied to the piezo element 417, whereby the size of the dot can be changed. In this way, each waveform portion is one unit applied to the piezo element 417. Note that control for applying each waveform portion to the piezo element 417 will be described in detail later.

The latch signal LAT is a signal indicating a repetition period T (a period in which the head 41 moves in a section of one pixel). That is, the latch signal LAT is generated by the controller 60 based on the signal of the linear encoder 51 output every time the carriage 31 moves by a predetermined distance, and the control logic 84 and the latch circuit (first latch circuit 82A, second latch circuit) are generated. Latch circuit 82
B).

The change signal CH is a signal indicating a period obtained by dividing the repetition period T into three equal parts. The change signal CH is generated by the controller 60 based on the signal from the linear encoder 51 and input to the control logic 84.

The pixel data SI is a signal indicating the gradation (no dot, small dot, medium dot, large dot) for each pixel. This pixel data is composed of 2 bits for each nozzle. For example, when the number of nozzles is 64, pixel data SI of 2 bits × 64 has a repetition period T
It will be sent from the controller 60 every time. The pixel data SI is input to the first shift register 81A and the second shift register 81B.

The clock signal CLK is a signal used when the pixel data SI sent from the controller 60 is set in each shift register (first shift register 81A, second shift register 81B).

Next, signals generated by the head controller HC will be described. In the head controller HC,
Selection signals q0 to q3, a switch control signal SW, and an application signal are generated.
The selection signals q0 to q3 are generated by the control logic 64 based on the latch signal LAT and the change signal CH. Then, the generated selection signals q0 to q3 are input to the decoders 83 provided for each piezo element 417.

The switch control signal SW is sent to each latch circuit (first latch circuit 82A, second latch circuit 82).
One of the selection signals q0 to q3 is selected by the decoder 83 based on the pixel data (2 bits) latched in B). The switch control signal SW generated by each decoder 83 is input to the corresponding switch 86.

The applied signal is output from the switch 86 based on the common drive signal COM and the switch control signal. This applied signal is applied to each piezo element 417 corresponding to each switch 86.

(Operation of the head controller HC)
The head controller HC performs control for ejecting ink based on the pixel data SI from the controller 60. That is, the head control unit HC controls the on / off of the switch 86 based on the print data, and selectively applies the necessary waveform portion of the common drive signal COM to the piezo element 417. In other words, the head controller HC controls the driving of each piezo element 417. In the present embodiment, the pixel data SI is composed of 2 bits. The pixel data SI is sent to the recording head 41 in synchronization with the transfer clock CLK. Further, the upper bit group of the pixel data SI is set in each first shift register 81A, and the lower bit group is set in each second shift register 81B. A first latch circuit 82A is electrically connected to the first shift register 81A, and a second latch circuit 82B is electrically connected to the second shift register 81B. When the latch signal LAT from the controller 60 becomes H level, each first latch circuit 82A latches the upper bit of the corresponding pixel data SI, and each second latch circuit 82B latches the lower bit of the pixel data SI. . Pixel data SI (latched by the first latch circuit 82A and the second latch circuit 82B)
Each set of upper bits and lower bits is input to the decoder 83. Decoder 8
3 is one of the selection signals q0 to q3 output from the control logic 84 in accordance with the pixel data SI latched by the first latch circuit 82A and the second latch circuit 82B.
For example, the selection signal q1) is selected, and the selected selection signal is output as the switch control signal SW. Each switch 86 is turned on / off according to the switch control signal, and the drive signal COM
Are selectively applied to the piezoelectric element 417.

(Relationship between pixel data and dots)
First, a case where dots are not formed (when pixel data SI is data [00]) will be described. When the pixel data [00] is latched, the selection signal q0 is output as the switch control signal SW. The selection signal q0 is for the nozzle whose pixel data SI is [00].
The control logic 84 outputs a signal indicating whether the switch 86 is turned on or off at an arbitrary time, and the control logic 84 outputs the pulse of the latch signal LAT or the change signal CH (as determined in advance). ) Value is defined (the same applies to the selection signals q1 to q3).
. Accordingly, the switch 86 is turned off in the period T. As a result, the drive pulse of the common drive signal COM is not applied to the piezo element 417. In this case, ink droplets are not ejected from the nozzles.

Next, a case where small dots are formed (when pixel data SI is data [01]) will be described. When the pixel data [01] is latched, the selection signal q1 is output as the switch control signal SW. Accordingly, the switch 86 is turned on in the period T11,
In the period T12 and the period T13, the switch 86 is turned off. As a result, the drive pulse PS1 included in the first waveform portion SS11 of the common drive signal COM is applied to the piezo element 417, and an ink droplet corresponding to a small dot is ejected from the nozzle.

Next, the case of forming a medium dot (when the pixel data SI is data [10]) will be described. When the pixel data [10] is latched, the selection signal q2 is output as the switch control signal SW. Accordingly, the switch 86 is turned on in the periods T11 and T12, and the switch 86 is turned off in the period T13. As a result, the drive pulse PS1 included in the first waveform portion SS11 of the common drive signal COM and the drive pulse PS2 included in the second waveform portion SS12 of the common drive signal COM are applied to the piezo element 417, and the nozzle corresponds to the medium dot. An amount of ink droplet (medium ink droplet) is ejected.

Next, a case where large dots are formed (when pixel data SI is data [11]) will be described. When the pixel data [11] is latched, the selection signal q3 is output as the switch control signal SW. Accordingly, the switch 86 is turned on in the period T11, the period T12, and the period T13. As a result, the drive pulse PS1 included in the first waveform portion SS11 of the common drive signal COM and the drive pulse P included in the second waveform portion SS12 of the common drive signal COM.
S2 and the drive pulse PS3 included in the third waveform portion SS13 of the common drive signal COM are sequentially applied to the piezo element 417, and ink droplets (large ink droplets) corresponding to large dots are ejected from the nozzles.

<Wiring from the head controller HC to the piezo element>
Next, wiring from the head controller HC to the piezoelectric element will be described with reference to FIG.
FIG. 5 is an exploded perspective view around the head controller HC.

First, the configuration of the head portion of this embodiment will be described. As shown in FIG. 5, the printer 1 of this embodiment includes a head 41 and a tape carrier package (Tape Car
rier Package: hereinafter also referred to as “TCP”).

The head 41 includes a nozzle plate 42, a reservoir plate 43, and an actuator unit 44. The nozzle plate 42 has six rows of nozzle openings. Further, for each of the rows, 64 nozzle openings are formed side by side in the transport direction.
In the following description, the nozzles are numbered # 1 to # 64 in order from the downstream side in the transport direction.
The reservoir plate 43 forms a reservoir (storage chamber) for storing ink and a pressure generation chamber for each nozzle. The actuator section 44 is provided with a piezo element corresponding to each nozzle, and the pressure generating chamber of the reservoir plate 43 is expanded and contracted according to the operation of the piezo element. The actuator unit 44 is provided with a connection terminal Ta for each nozzle (for each piezo element). That is, 64 connection terminals Ta are provided for each nozzle row.

The TCP is configured by mounting a head controller HC that controls driving of the head based on an input signal from the main body side (controller 60) on an FPC (Flexible Printed Circuit) and forming a necessary wiring pattern. The head controller HC is configured by a semiconductor integrated circuit (IC).

The wiring on the input side of the head controller HC is the common drive signal COM and the latch signal LAT described above.
, A change signal CH, pixel data SI, a clock signal CLK, and the like.

Further, although not shown in the figure, the wiring on the output side of the head controller HC transmits the applied signal to each piezo element.

In addition, connection terminal Tb for connecting with connection terminal Ta of the actuator part 44 is provided in TCP for every nozzle. That is, 64 connection terminals T per nozzle row
b is provided. Each connection terminal Tb of the TCP corresponds to each connection terminal Ta of the actuator section 44. The applied signal output from the head controller HC is applied to the piezoelectric element through the connection terminal Tb and the connection terminal Ta through the wiring on the output side.

<About the head case 45>
Here, the head case 45 will be described with reference to FIGS. 6 and 7. FIG. 6 is a schematic diagram showing the head unit 40 mounted on the carriage 31, and a head case 45.
The configuration is shown by a cross-sectional view. FIG. 7 is a diagram for explaining an operation example of the variable opening 48. FIG. 7A shows a hollow portion 46 when the carriage 31 moves in one direction of movement (outward path).
It is a figure which shows the state of. FIG. 7B is a diagram illustrating a state of the cavity 46 when the carriage 31 moves in the other direction (return path) of the movement direction. In FIG. 7, the cavity 46 and the TCP (head controller HC) in the head unit 40 are extracted and shown.

(Heat generation of head controller HC)
As described above, the head controller HC controls the on / off of the switch 86 based on the print data, and selectively applies a necessary waveform portion of the common drive signal COM to the piezo element 417, thereby obtaining a predetermined magnitude. The ink droplet is ejected from the nozzle toward the medium S. In the printer 1 according to the present embodiment, printing is performed by repeating such ink droplet ejection.

However, when printing is performed for a long time, on / off control of whether or not to apply a drive signal to the drive element is frequently repeated by the switch 86. As a result, excessive heat is generated from the transistors constituting the switch 86, and the temperature in the head controller HC increases significantly. As a result, ejection failure or the like occurs, causing the printer 1 to malfunction.

On the other hand, in the head unit 40 according to the present embodiment, the cavity 46 having the metal part 47 is formed in the head case 45 so that the head controller HC is brought into contact with the metal part 47. A variable opening 48 whose opening size can be changed is provided in the cavity 46, and the air flowing from the variable opening 48 by the movement of the carriage 31 is applied to the metal part 47 to be cooled. Thereby, the heat generated by the head controller HC can be effectively dissipated.
Hereinafter, a configuration example of the head case 45 will be specifically described.

(Configuration of head case 45)
First, the configuration of the head case 45 according to the present embodiment will be described with reference to FIG.
In the head unit 40 shown in FIG. 6, the ink introduction needle, the ink flow path, and the like to which the ink cartridge CRG is attached are omitted. Further, the head case 45 shown in FIG.
In FIG. 1, although the upper surface is illustrated in an open state, it is assumed to be sealed.

The head case 45 is a casing that is supported by the carriage 31 and configured to accommodate the head 41 and the head controller HC.
The head case 45 is mainly formed of a synthetic resin and includes a hollow portion 46 having a portion 47 (hereinafter referred to as “metal portion 47”) formed of a metal member. The head case 45 has a nozzle plate 42 on the bottom surface.

A reservoir plate 43 is adhered to the upper surface of the nozzle plate 42 with a film adhesive.
A supply plate (not shown) for supplying ink to the reservoir plate 43 side is adhered to the upper surface of the reservoir plate 43 with a film adhesive.
An actuator portion 44 is bonded to the upper surface of the supply plate with a film adhesive.

A TCP having a head control unit HC is bonded to the upper surface of the actuator unit 44. By bonding in this way, each connection terminal Tb of TCP is connected corresponding to each connection terminal Ta of the actuator portion 44 (see FIG. 5).

Since this TCP is formed of a flexible member, it can be bent freely.
In this embodiment, as shown in FIG. 6, the TCP is bent upward along the inner wall of the head case 45 so that the head controller HC is in contact with the metal part 47. The head controller HC is bonded to the metal part 47 with an adhesive made of a material having high thermal conductivity.

Thus, since the head controller HC is accommodated in the case in contact with the metal part 47, the heat generated by the head controller HC is dissipated from the surface of the metal part 47 into the air.

Further, as shown in FIG. 6, the TCP is bent in the downstream direction in the transport direction, and the end portion of the TCP opposite to the actuator portion 44 side is fixed to the substrate CB. A connector CN is mounted on the substrate CB. TCP is connected to the connector C via the substrate CB.
N is electrically connected. A flexible cable 71 having flexibility is connected to the connector CN.

For this reason, when the common drive signal COM generated by the drive signal generator 65 is transmitted from the main body side (controller 60) to the head unit 40 side, the flexible cable 71
Are received by the actuator unit 44 via the connector CN, the substrate CB, and the TCP sequentially.

Further, as shown in FIG. 6, the head case 45 includes a first side surface 45a downstream of the guide rail 33 in the transport direction and a second side surface 45b downstream of the first side surface 45a in the transport direction. And have.

In the present embodiment, the cavity portion 4 is provided on the second side surface portion 45b side of the head case 45.
6 is provided.
As shown in FIG. 7, the cavity 46 is provided along the moving direction, and has variable openings 48, 48 on one side and the other side of the moving direction, and between the variable openings 48, 48. A metal part 47 is provided.

For this reason, when the carriage 31 moves in the moving direction, the wind flows into the cavity 46 through the variable opening 48 serving as an entrance.
If it does so, the wind which flowed in in the cavity 46 will hit the surface of the metal part 47, and the heat which the head control part HC generated from the surface will be dissipated.

Further, by providing the hollow portion 46 on the second side surface portion 45b side, the second side surface portion 45b side is closer to the discharge port side for discharging the medium S than the first side surface portion 45a side. Air outside the low-temperature printer flows into the cavity 46 from the variable opening 48.

As a result, since the low-temperature outside air that has flowed into the cavity 46 touches the surface of the metal part 47, heat is taken away, so that the heat dissipation effect can be further improved.

As shown in FIG. 6, the metal portion 47 is fixed to the head case 45 in a state where the tip of the protruding portion 47 a is in contact with the second side surface portion 45 b of the head case 45. Thereby, the metal part 4
7 and the head case 45 form a cavity 46.

In the present embodiment, the metal part 47 is set to the ground potential. Thus, the metal part 4
7 is grounded (grounded), the static electricity charged in the head controller HC or the like can be gradually reduced, and the head controller is damaged by static electricity or the static electricity is superimposed on the drive signal as noise. It becomes possible to suppress malfunction.

As shown in FIG. 7, the variable opening 48 includes a shaft 48a, a flap 48b that rotates about the shaft 48a, and a motor (not shown) as an example of a drive unit that rotates the flap 48b about the shaft 48a. And have.
That is, the controller 60 drives the motor to generate the flap 48b.
Can be rotated around the shaft 48a.
And the variable opening part 48 can change the magnitude | size of opening by the flap 48b rotating.
In this way, the controller 60 controls each variable opening 48 so that the cavity 46
The amount of air flowing into the interior can be adjusted.

<<< Operation Example of Printer 1 >>>
Next, an operation example of the printer 1 will be described with reference to FIG.
When print data is sent from the computer 110, the printer 1 executes print processing. Each process described below is executed by the controller 60 controlling each unit in accordance with a program stored in the memory 63. This program has a code for executing each process.

The controller 60 is connected to the computer 110 via the interface unit 61.
A print command is received. This print command is included in the header of print data transmitted from the computer 110. Then, the controller 60 analyzes the contents of various commands included in the received print data, and performs the following paper feed process, transport process, ink ejection process, and the like using each unit.

<Paper feed processing>
First, the controller 60 performs a paper feed process. The paper feed process is a process for supplying the paper S to be printed into the printer 1 and positioning the paper S at a print start position (also referred to as a cue position). The controller 60 rotates the paper feed roller 21 and sends the paper S to be printed to the transport roller 23. The controller 60 rotates the transport roller 23 and positions the paper fed from the paper feed roller 21 at the print start position. When the paper S is positioned at the print start position, at least some of the nozzles of the head 41 are opposed to the paper S.

<Dot formation process>
Next, the controller 60 performs a dot formation process. The dot formation process is a process for forming dots on paper by intermittently ejecting ink from the head 41 moving along the carriage movement direction. The controller 60 drives the carriage motor 32 to reciprocate the carriage 31 in the carriage movement direction. Then, the controller 60 ejects ink from the head 41 based on the print data while the carriage 31 is moving. When ink droplets ejected from the head 41 land on the paper, dots are formed on the paper.

<Cooling treatment>
During the dot formation process, the controller 60 performs a cooling process. What is cooling?
This is a process of changing the size of the openings in the variable openings 48 and 48 in accordance with the traveling direction of the carriage 31.

That is, when the carriage 31 reciprocates in the movement direction along the guide rail 33, the controller 60 controls the rotation of the flaps 48 b and 48 b in accordance with the traveling direction, and the air flowing into the cavity 46. By adjusting the amount, the metal part 47 that has become hot due to the heat generated by the head controller HC is cooled.

Specifically, as shown in FIG. 7A, the controller 60 drives the motor when the carriage 31 is in the forward path, so that the flaps 48b, 48b of the variable openings 48, 48 are driven.
Are rotated counterclockwise.

As a result, the opening size of the variable opening portion 48 on the front side in the traveling direction (one side variable opening portion) can be made larger than the variable opening portion 48 on the rear side in the traveling direction (variable opening portion on the other side). .
Then, a large amount of air is taken into the cavity 46 from the variable opening 48 on the front side in the traveling direction, and a small amount of air is discharged from the variable opening 48 on the rear side in the traveling direction.
6, the amount of heat released from the surface of the metal part 47 into the air can be increased. For this reason, the metal part 47 can be air-cooled more efficiently.

On the other hand, as shown in FIG. 7B, when the carriage 31 is in the return path, the controller 60 drives the motor to rotate the flaps 48b, 48b of the variable openings 48, 48 clockwise, respectively. .

As a result, the opening size of the variable opening portion 48 on the front side in the traveling direction (one side variable opening portion) can be made larger than the variable opening portion 48 on the rear side in the traveling direction (variable opening portion on the other side). .
For this reason, the metal part 47 can be air-cooled more efficiently as in the forward path.

<Transport processing>
Next, the controller 60 performs a conveyance process. The transport process is a process of moving the paper S relative to the head 41 along the transport direction. The controller 60 drives the transport motor 22 and rotates the transport roller 23 to transport the paper S in the transport direction. By this carrying process, the head 41 can form dots at positions different from the positions of the dots formed by the previous dot formation process.

<Discharge judgment>
Next, the controller 60 determines whether or not to discharge the paper S being printed. If data for printing on the paper S being printed remains, the paper is not discharged. And the controller 60 is
Dot formation processing and conveyance processing are alternately repeated until there is no more data to be printed, and an image composed of dots is gradually printed on the paper S. The determination of whether or not to discharge paper may be based on a paper discharge command included in the print data.

<Discharge processing>
Next, the controller 60, when there is no data to be printed on the paper S being printed,
The paper S is discharged. The controller 60 discharges the printed paper S to the outside by rotating the paper discharge roller 25.

<Print end judgment>
Next, the controller 60 determines whether or not to continue printing. If printing is to be performed on the next paper S, the printing is continued and the paper feeding process for the next paper S is started. If printing is not performed on the next paper S, the printing operation is terminated.

As described above, when the carriage 31 reciprocates, the opening size of the variable opening 48 on the front side in the traveling direction of the carriage 31 is made larger than the opening size of the variable opening 48 on the rear side in the traveling direction. As a result, the amount of air taken into the cavity 46 can be increased, and the taken-in air can pass through without stagnation, so that the metal part 47 is air-cooled more efficiently.

As a result, the heat generated by the head controller HC can be efficiently dissipated from the surface of the metal part 47, and the occurrence of malfunction of the head controller HC can be suppressed.

=== Other Embodiments ===
Although the present embodiment is mainly described with respect to a liquid discharge apparatus, disclosure of a liquid discharge method and the like is also included. Further, the present embodiment is intended to facilitate understanding of the present invention and is 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.

<Liquid ejection device>
In the above embodiment, the ink jet printer has been described as an example of the liquid ejection device, but the present invention is not limited to this. For example, a liquid ejection device that ejects liquid other than ink may be used. The present invention can be used for various liquid ejecting apparatuses including a liquid ejecting head that ejects a minute amount of liquid droplets. In addition, a droplet (ink droplet) means the state of the liquid ejected from the liquid ejecting apparatus, and includes one that has a tail in a granular shape, a tear shape, or a thread shape. The liquid here may be any material that can be discharged by the liquid discharge device. For example, it may be in a state in which the substance is in a liquid phase, such as a liquid with high or low viscosity, sol, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals (metal melts ) And a liquid as one state of a substance, as well as a material in which particles of a functional material made of a solid such as a pigment or metal particles are dissolved, dispersed or mixed in a solvent. Further, representative examples of the liquid include ink and liquid crystal as described in the above embodiment. Here, the ink includes general water-based inks and oil-based inks, and various liquid compositions such as gel inks and hot melt inks. As a specific example of the liquid ejection device, for example, a liquid containing a material such as an electrode material or a color material used for manufacturing a liquid crystal display, an EL (electroluminescence) display, a surface emitting display, a color filter or the like in a dispersed or dissolved form. It may be a liquid ejecting apparatus for ejecting, a liquid ejecting apparatus for ejecting a bio-organic material used for biochip manufacturing, a liquid ejecting apparatus for ejecting liquid as a sample used as a precision pipette, a textile printing apparatus, a microdispenser, or the like. In addition, a transparent resin liquid such as UV curable resin is used to form a liquid ejection device that ejects lubricating oil pinpoint to precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. A liquid discharge apparatus that discharges an acid or alkali or the like to etch the substrate or the like may be employed. The present invention can be applied to any one of these liquid ejection devices.

<About others>
Although the case of TCP has been described in the above embodiment, the present invention is not limited to TCP. For example, COF (Chip On Film) may be used.
In the above embodiment, one head controller HC controls six nozzle rows, but the present invention is not limited to this. One head controller HC may control only one nozzle row.

1 printer, 20 transport unit,
21 paper feed roller, 22 transport motor (PF motor),
23 transport roller, 24 platen, 25 discharge roller,
30 Carriage unit, 31 Carriage,
32 Carriage motor (CR motor),
40 head units, 41 heads,
45 head case, 45a first side surface, 45b second side surface,
46 cavity part, 47 metal part, 48 variable opening part,
48a rotating shaft, 48b flap,
50 detector groups, 51 linear encoders,
52 Rotary encoder, 53 Paper detection sensor,
54 optical sensors, 60 controllers,
61 interface unit, 62 CPU, 63 memory,
64 unit control circuit, 65 drive signal generator,
71 Flexible cable,
81A first shift register, 81B second shift register,
82A first latch circuit, 82B second latch circuit,
83 Decoder, 84 Control logic, 86 Switch,
110 computers, 417 piezo elements,
HC head controller

Claims (4)

A carriage that moves in a crossing direction that intersects the transporting direction of transporting the medium;
A head portion provided on the carriage,
A nozzle, a drive element that discharges liquid from the nozzle, and a head control unit that includes a switch that performs on / off control as to whether or not to apply a drive signal to the drive element, and that controls driving of the drive element. The head,
A cavity provided along the crossing direction,
A variable opening provided to be able to change the size of the opening on one side and the other side in the crossing direction;
A cavity portion that is provided between the variable opening portions in contact with the head control portion, and that cools the air flowing from the variable opening portions by movement of the carriage against the metal portion. When,
A liquid ejection apparatus comprising: The liquid ejection device according to claim 1,
When the variable opening located on the front side in the traveling direction of the carriage is the one side variable opening and the variable opening located on the rear side in the traveling direction of the carriage is the other side variable opening In addition,
The liquid ejecting apparatus according to claim 1, wherein the variable opening on the one side is larger in size than the variable opening on the other side. The liquid ejection device according to claim 1 or 2,
The liquid ejecting apparatus according to claim 1, wherein the metal part is grounded. The liquid ejection device according to any one of claims 1 to 3,
The carriage is
It is guided by the guide rail and moves in the crossing direction,
The head portion is
A head case having a first side surface downstream of the guide rail in the transport direction and a second side surface downstream of the first side surface in the transport direction;
The liquid ejecting apparatus according to claim 1, wherein the hollow portion is provided on the second side surface side of the head case.