JP2017159607A - Liquid injection head, liquid injection device, and control method for liquid injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid injection device capable of suppressing destruction of a meniscus in a nozzle when insides of liquid flow passages are decompressed after compression thereof, and a control method for the liquid injection device.SOLUTION: A liquid injection device comprises a flexible member partitioning parts of liquid flow passages 21, 26, 90 and 93 and being deformable by drive of a pump 80. When deforming the flexible member and changing a volume of a partial flow passage 110 partitioned by the flexible member out of the liquid flow passages 21, 26, 90 and 93 from a first volume to a second volume greater than the first volume, the liquid injection device deforms the flexible member such that a change speed of the volume of the partial flow passage 110 does not exceed a speed at which a meniscus of a nozzle 24 is destructed.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a liquid ejecting head including a nozzle that ejects liquid, a liquid ejecting apparatus, and a control method for the liquid ejecting apparatus, and more particularly, to adjust the pressure in a liquid flow path communicating with the nozzle to adjust the position of the meniscus. The present invention relates to a liquid ejecting head to be controlled, a liquid ejecting apparatus, and a method for controlling the liquid ejecting apparatus.

  As a liquid ejecting apparatus on which the liquid ejecting head is mounted, for example, there is an image recording apparatus such as an ink jet printer or an ink jet plotter, but recently, a very small amount of liquid can be accurately landed on a predetermined position. The liquid ejecting head is also applied to various manufacturing apparatuses utilizing the above. For example, a display manufacturing apparatus for manufacturing a color filter such as a liquid crystal display, an electrode forming apparatus for forming an electrode such as an organic EL (Electro Luminescence) display or FED (surface emitting display), and a chip for manufacturing a biochip (biochemical element) Applied to manufacturing equipment. The recording head for the image recording apparatus ejects liquid ink, and the color material ejecting head for the display manufacturing apparatus ejects solutions of R (Red), G (Green), and B (Blue) color materials. The electrode material ejecting head for the electrode forming apparatus ejects a liquid electrode material, and the bioorganic matter ejecting head for the chip manufacturing apparatus ejects a bioorganic solution.

  The liquid ejecting head includes a nozzle that is open on the nozzle surface, a pressure chamber that communicates with the nozzle, and an actuator such as a piezoelectric element that varies the pressure in the pressure chamber, and the pressure in the liquid in the pressure chamber is changed by driving the actuator. The droplet is ejected from the nozzle. The inside of the pressure chamber and the liquid flow path communicating with the pressure chamber is set to a negative pressure so that the surface of the liquid in the nozzle (hereinafter referred to as a meniscus) can be held at an appropriate position. However, this negative pressure may cause bubbles to be drawn into the nozzle, for example, during a wiping operation for wiping the nozzle surface. In order to suppress such inconveniences, a configuration in which the inside of the liquid channel can be pressurized by a pressure adjusting means during a wiping operation or the like is disclosed (for example, Patent Document 1).

Japanese Patent Laying-Open No. 2015-193213

  By the way, when the inside of the liquid channel is pressurized by the pressure adjusting means and then decompressed to return to the original negative pressure, the meniscus may be destroyed. That is, as the pressure in the liquid flow path is reduced, the meniscus may be drawn into the back of the nozzle and be out of the proper position in the nozzle. The operation in which the pressure in the liquid channel is reduced is not limited to the return operation after the wiping operation as described above. For example, in order to suppress thickening in the nozzles, it is conceivable that the position of the meniscus is moved deeper than the position of the meniscus when the liquid is ejected when the printing operation is not performed. However, if the meniscus is pulled too far into the nozzle, the meniscus may not be returned to an appropriate position during a printing operation. That is, the meniscus may be destroyed.

  The present invention has been made in view of such circumstances, and the purpose thereof is a liquid ejecting apparatus capable of suppressing the destruction of a meniscus in a nozzle when depressurizing after pressurizing the inside of a liquid flow path, and It is an object to provide a method for controlling a liquid ejecting apparatus.

A liquid ejecting head according to the present invention has been proposed to achieve the above object, and includes a nozzle opened in a nozzle surface, a pressure chamber communicating with the nozzle, and a liquid flow for supplying liquid to the pressure chamber. A liquid jet head having a path,
A part of the liquid flow path is partitioned, and provided with a flexible member that can be deformed by driving the deformation means,
When the flexible member is deformed to change the volume of the partial flow path partitioned by the flexible member in the liquid flow path from the first volume to a second volume larger than the first volume. The flexible member is deformed so that the changing speed of the volume of the partial flow path does not exceed the speed at which the meniscus of the nozzle is destroyed.

  According to the present invention, when the partial flow path is changed from the first volume to the second volume, the meniscus in the nozzle communicating with the partial flow path can be suppressed from being destroyed. Here, the state where the meniscus is destroyed is a state where the meniscus is pulled into the back of the nozzle and normal injection (also referred to as discharge) cannot be performed, or the meniscus cannot be returned to a position where normal injection can be performed. .

  In the above configuration, it is preferable that the volume of the partial flow path is changed from the first volume to the second volume in a state where the nozzle is covered with the cap.

  According to this structure, it can suppress that the liquid in a nozzle thickens.

Furthermore, in any of the above-described configurations, the inner surface of the nozzle has a liquid repellent region having liquid repellency with respect to the liquid in order from the end opposite to the pressure chamber, and a lyophilic liquid with respect to the liquid. A lyophilic region having sex,
It is desirable to change the volume of the partial flow path from the first volume to the second volume so that the meniscus of the nozzle moves from the liquid repellent area side to the lyophilic area.

  According to this configuration, the meniscus can be returned to an appropriate position in the nozzle. As a result, it is possible to suppress an ejection failure in which the liquid is not ejected normally.

  In any of the above-described configurations, when the volume of the partial flow path is changed from the second volume to the first volume and then changed from the first volume to the second volume. The change rate of the volume of the partial flow path that changes from the second volume to the first volume is greater than the change speed of the volume of the partial flow path that changes from the first volume to the second volume. It is desirable to deform the flexible member so as to be faster. For example, the change speed of the volume of the partial flow path that changes from the second volume to the first volume may be a speed that exceeds the speed at which the meniscus of the nozzle is destroyed.

  According to this configuration, the change from the second volume to the first volume is accelerated, and the pressurizing operation for pressurizing the liquid flow path is accelerated.

  According to another aspect of the invention, a liquid ejecting apparatus includes the liquid ejecting head having any one of the above-described configurations.

  According to this configuration, it is possible to suppress an ejection failure in which the liquid is not ejected normally, and to improve the reliability of the liquid ejecting apparatus.

Further, in the above configuration, a gas flow path in contact with the liquid flow path with the flexible member interposed therebetween,
The gas flow path includes a resistance applying unit that provides resistance to the flowing gas,
It is desirable to change the volume of the partial flow path from the first volume to the second volume by deforming the flexible member by reducing the pressure in the gas flow path through the resistance applying portion.

  According to this configuration, the pressure-reducing speed in the gas flow path can be reduced by the resistance applying unit. Thereby, the change speed of the volume of the partial flow path can be slowed down, and consequently the moving speed of the meniscus can be slowed down. As a result, destruction of the meniscus in the nozzle can be suppressed. Further, for example, the configuration is simplified as compared with the case where the pressure in the gas flow path is managed using an atmospheric pressure sensor or the like.

Furthermore, in the above configuration, a pressurizing mechanism that pressurizes the inside of the gas flow path;
In the gas flow path between the flexible member and the resistance applying portion, an open state that allows a gas flow in the gas flow path, and a closed state that inhibits a gas flow in the gas flow path A gas flow path opening / closing valve that can be converted into
When changing the volume of the partial flow path from the second volume to the first volume, the gas flow path opening / closing valve is closed and the pressurizing mechanism is more flexible than the gas flow path opening / closing valve. When the flexible member is deformed by pressurizing the inside of the gas flow path on the member side, and the volume of the partial flow path is changed from the second volume to the first volume, the gas flow path opening / closing valve It is desirable that the flexible member is deformed by opening the gas passage and reducing the pressure in the gas flow path through the resistance applying portion.

  According to this configuration, by closing the gas flow path opening / closing valve, the inside of the gas flow path can be pressurized without going through the resistance applying portion. Thereby, the inside of a gas channel can be pressurized efficiently.

Moreover, in any one of the above configurations, a wiper for wiping the nozzle surface is provided,
The wiper preferably wipes the nozzle surface in a state where the volume of the partial flow path is changed to the first volume.

  According to this configuration, when the volume of the partial flow path is at the first volume, if the negative pressure in the liquid flow path is released, bubbles are generated when the wiper wipes the nozzle surface. The malfunction drawn in can be suppressed.

Further, in any one of the above-described configurations, in the liquid flow channel upstream of the partial flow channel, an open state in which the liquid flow in the liquid flow channel is allowed, and the liquid flow in the liquid flow channel are It has a liquid flow path opening and closing valve that can be converted into a closed state that inhibits,
The liquid flow path opening / closing valve is closed to change the volume of the partial flow path from the second volume to the first volume, while the liquid flow path opening / closing valve is opened to open the partial flow path. It is desirable to change the volume of the first volume from the first volume to the second volume.

  According to this configuration, when the volume of the partial flow path is changed from the second volume to the first volume, the liquid flow path opening / closing valve is in the closed state. Propagation to the liquid channel upstream of the channel opening / closing valve can be suppressed. Thereby, the pressure chamber can be efficiently pressurized. In addition, when changing the volume of the partial flow path from the first volume to the second volume, the liquid flow path opening / closing valve is in an open state, so that the meniscus is caused by the supply of liquid from the upstream liquid flow path. It can suppress that it is drawn too deeply into the nozzle. As a result, the meniscus in the nozzle can be further prevented from being destroyed. Furthermore, the pressure fluctuation in the liquid flow path caused by the opening / closing operation of the liquid flow path opening / closing valve can be absorbed by the partial flow path. For this reason, the opening / closing operation of the liquid flow path opening / closing valve can be accelerated.

And the control method of the liquid ejecting apparatus in the present invention includes a nozzle that is opened in a nozzle surface, a pressure chamber that communicates with the nozzle, and a liquid ejecting head that includes a liquid flow path that supplies liquid to the pressure chamber; A gas channel in contact with the liquid channel across a flexible member that partitions a part of the liquid channel, a pressurizing mechanism that pressurizes the gas channel, and a wiper that wipes the nozzle surface A control method of a liquid ejecting apparatus provided,
By pressurizing the inside of the gas channel by the pressurizing mechanism, the inside of the liquid channel is pressurized at a first speed from a first pressure to a second pressure, and the nozzle surface is moved by the wiper in this pressurized state. After wiping, the inside of the liquid channel is depressurized from the second pressure to the first pressure at a second speed that is slower than the first speed.

  According to this configuration, it is possible to suppress a problem that bubbles are drawn into the nozzle when the nozzle surface is wiped with the wiper. Further, when the inside of the liquid channel is depressurized from the second pressure to the first pressure, the meniscus in the nozzle can be prevented from being destroyed.

2 is a perspective view illustrating an internal configuration of the printer. FIG. FIG. 3 is an exploded perspective view of the recording head as viewed obliquely from above. FIG. 3 is a cross-sectional view of a recording head. It is a schematic diagram explaining the gas flow path and liquid flow path in a recording head. It is a schematic diagram explaining the internal structure of a pressure adjustment member. It is sectional drawing of a unit head. It is a schematic diagram explaining a wiping operation | movement. It is a schematic diagram explaining a wiping operation | movement. It is a schematic diagram explaining a wiping operation | movement.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. Note that, in the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to this embodiment. In the following description, an ink jet recording head (hereinafter referred to as recording head) 3 mounted on an ink jet printer (hereinafter referred to as printer) 1 which is a kind of liquid ejecting apparatus is taken as an example of the liquid ejecting head of the present invention. Do it.

  The configuration of the printer 1 will be described with reference to FIG. The printer 1 is an apparatus that records an image or the like by ejecting liquid ink onto the surface of a recording medium 2 such as recording paper. The printer 1 supports a recording head 3 including a plurality of liquid ejecting units 4, a transport mechanism 5 for transporting a recording medium 2, and a recording medium 2 transported to a position facing the nozzle surface of the liquid ejecting unit 4. A medium support 6 (also called a platen) is provided inside the apparatus main body 7. Further, a wiper 9 that wipes the nozzle surface 23a (see FIG. 6) and a cap 10 that covers the nozzle surface 23a and seals the nozzle 24 that opens to the nozzle surface 23a are disposed at a position away from the medium support portion 6. Has been. The wiper 9 is a thin plate member made of an elastic member such as an elastomer. The cap 10 is a member having a sealed space opened upward (to the recording head 3 side). Each of the wiper 9 and the cap 10 is configured to be moved below the recording head 3 by a driving mechanism (not shown) so as to contact the nozzle surface.

  Furthermore, a first pump 79 and a second pump 80 (see FIG. 4) that send gas (air in the present embodiment) to the recording head 3 are attached to the apparatus body 7 of the printer 1. The first pump 79 supplies air to the recording head 3 via the first gas supply tube 77, and the second pump 80 (corresponding to the pressurizing mechanism in the present invention) is the second gas supply tube 78. Then, air is supplied to the recording head 3 via. As shown in FIG. 4, the first gas supply tube 77 includes a first branch path 81 that is branched downstream of the first pump 79 (that is, the recording head 3 side). The first branch path 81 is open to the atmosphere at the end opposite to the branch portion. A first valve 87 for opening and closing the inside of the first branch path 81 is provided in the middle of the first branch path 81. The first valve 87 is configured to be convertible between an open state that allows air flow in the first branch path 81 and a closed state that blocks air flow in the first branch path 81. Yes. In addition, the second gas supply tube 78 includes a second branch path 82 branched from the downstream side of the second pump 80 (that is, the recording head 3 side). The second branch path 82 has an end opposite to the branch portion open to the atmosphere via a resistance applying portion 89. The resistance applying unit 89 is, for example, a part having an inner diameter smaller than the other part of the second branch path 82, and applies resistance to the air flowing through the resistance applying unit 89. In addition, the resistance provision part 89 in this embodiment is comprised so that the magnitude | size of the internal diameter can be changed. That is, the resistance applying unit 89 in the present embodiment is configured to be able to adjust the magnitude of resistance to air. Further, on the downstream side of the resistance applying portion 89 of the second branch path 82 (that is, the recording head 3 side), a second valve 88 that opens and closes the inside of the second branch path 82 (the gas flow in the present invention). Equivalent to a road opening / closing valve). The second valve 88 is configured to be convertible between an open state that allows air flow in the second branch 82 and a closed state that inhibits air flow in the second branch 82. Yes.

  As shown in FIG. 1, there are a plurality of recording heads 3 in this embodiment (four in this embodiment) in a direction (Y direction in FIG. 1 and the like) intersecting the transport direction (X direction in FIG. 1 and the like) of the recording medium 2. This is a line head that is long in the direction (Y direction) in which the liquid ejecting units 4 are arranged. The recording head 3 is connected to a liquid supply tube 76 that communicates with the inside of the ink cartridge 8 that stores ink, which is a kind of liquid. Ink from the ink cartridge 8 is supplied to the recording head 3 via the liquid supply tube 76. A configuration in which the ink cartridge is mounted on the recording head can also be employed. The recording head 3 is connected to a wiring member 11 such as an FFC that supplies a driving signal from a control unit (not shown) to the recording head 3. In addition to the recording head 3, the control unit includes the first pump 79, the second pump 80, the first valve 87, the second valve 88, the drive mechanism for driving the wiper 9, and the cap 10. The drive mechanism etc. which drive are controlled.

  The transport mechanism 5 includes a pair of upper and lower first transport rollers 12 a disposed on the upstream side in the transport direction of the recording medium 2 with respect to the medium support unit 6, and a pair of upper and lower sides on the downstream side in the transport direction with respect to the medium support unit 6. And a second transport roller 12b arranged. The recording medium 2 from the supply side is transported toward the discharge side through the medium support unit 6 while being sandwiched between the upper and lower rollers by driving of the transport rollers 12a and 12b. In FIG. 1, the upper roller of the pair of upper and lower rollers is not shown. In some cases, the transport mechanism includes an endless belt or a drum. In such a configuration, the belt or the drum functions as a medium support unit. Furthermore, as the medium support portion, a structure that adsorbs the recording medium by electrostatic force or a structure that adsorbs the recording medium by generating a negative pressure can be adopted.

  FIG. 2 is an exploded perspective view showing the configuration of the recording head 3. FIG. 3 is a cross-sectional view of the recording head 3. FIG. 4 is a schematic diagram for explaining a gas flow path and a liquid flow path in the recording head 3. FIG. 5 is a schematic diagram illustrating the internal configuration of the pressure adjusting member 14. In the following description, the stacking direction (Z direction) of the respective constituent members of the recording head 3 will be described as an appropriate vertical direction. As shown in FIGS. 2 and 3, the recording head 3 in the present embodiment adjusts the pressure of the ink flowing in the flow path member 13 in which the flow path for supplying ink to each liquid ejecting unit 4 is formed. The pressure adjustment member 14, the circuit board 15 that transmits a drive signal for controlling each liquid ejecting unit 4, the metal shield 16 that houses the pressure adjustment member 14 and the circuit board 15, and the bottom surface of the metal shield 16 are configured. And a liquid ejecting unit 4 attached to the lower surface of the metal base 51.

  The flow path member 13 is a synthetic resin plate-like member that supplies ink to each liquid ejecting unit 4, and as shown in FIG. 4, an upper liquid flow path 90 constituting a part of the liquid flow path through which the ink flows. Upper gas flow paths 91 and 92 that constitute a part of the gas flow path through which air flows are formed inside. As shown in FIG. 2, a plurality (four in this embodiment) of liquid supply tube connection portions 41 to which ink supply tubes corresponding to the respective colors are connected are formed on the upper surface of the flow path member 13. . The liquid supply tube connecting portion 41 is communicated with the liquid outlet 42 formed on the lower surface of the flow path member 13 via the upper liquid flow path 90 inside the flow path member 13. The upper liquid flow path 90 in the present embodiment is branched in the middle so that the ink flowing from one liquid supply tube connection portion 41 is distributed to the four liquid ejecting units 4, and communicates with the four liquid outlets 42. ing. That is, one liquid supply tube connecting portion 41 communicates with the four liquid outlets 42 via the upper liquid flow path 90.

  As shown in FIG. 2, a gas supply tube connecting portion 43 to which the first gas supply tube 77 and the second gas supply tube 78 are connected is formed on the upper surface of the flow path member 13. The gas supply tube connection part 43 connected to the first gas supply tube 77 is a gas outlet formed on the lower surface of the flow path member 13 via the first upper gas flow path 91 inside the flow path member 13. 44. In addition, the gas supply tube connection portion 43 connected to the second gas supply tube 78 is a gas formed on the lower surface of the flow path member 13 via the second upper gas flow path 92 inside the flow path member 13. It communicates with the outlet 44. The first upper gas flow path 91 and the second upper gas flow path 92 in the present embodiment are each branched in the middle and communicated with the four gas outlets 44. That is, one gas supply tube connecting portion 43 communicates with the four gas outlets 44 via the first upper gas flow path 91. The other gas supply tube connecting portion 43 communicates with the four gas outlets 44 via the second upper gas flow path 93. In addition, the flow path member 13 in this embodiment is mounted on the upper surface 65 of the metal cover 52 mentioned later.

  In the present embodiment, there are a plurality (specifically, eight) of gas outlets 44 along the longitudinal direction (Y direction) of the flow path member 13 at the approximate center in the short direction (X direction) of the flow path member 13. ) Is formed. Further, the liquid outlets 42 in this embodiment are arranged in parallel along the Y direction on both sides in the X direction of the row of gas outlets 44. In other words, a row of liquid outlets 42 formed by arranging a plurality (specifically, eight) of liquid outlets 42 is formed in two rows with the row of gas outlets 44 interposed therebetween. Further, the liquid outlet 42 and the gas outlet 44 in the present embodiment are formed in a cylindrical shape and project downward from the lower surface of the flow path member 13. The diameter of the liquid outlet 42 is smaller than the diameter of the gas outlet 44.

  The pressure adjusting member 14 is a synthetic resin member connected to the lower side of the flow path member 13 (on the liquid ejecting unit 4 side) with a metal cover 52 to be described later interposed therebetween. A plurality of liquid inlets 46 corresponding to the liquid outlets 42 of the flow path member 13 and a plurality of gas inlets 47 corresponding to the gas outlets 44 of the flow path member 13 are formed on the upper surface of the pressure adjusting member 14. ing. As shown in FIG. 3, the connecting portion between the liquid outlet 42 and the liquid inlet 46 and the connecting portion between the gas outlet 44 and the gas inlet 47 are below the metal cover 52 (that is, an accommodation space described later). 68). Further, as shown in FIG. 4, a lower liquid channel 93 is formed inside the pressure adjusting member 14. The liquid inlet 46 communicates with a liquid outflow pipe 48 projecting below the pressure adjusting member 14 via a lower liquid flow path 93. Further, a first lower gas flow path 94 and a second lower gas flow path 95 are formed inside the pressure adjusting member 14. The gas outlet 44 communicating with the first upper gas flow path 91 is connected to a choke chamber 97 described later via a first lower gas flow path 94. In addition, the gas outlet 44 communicating with the second upper gas flow path 92 is connected to a tank chamber 98 described later via a second lower gas flow path 95.

  That is, as shown in FIG. 4, the ink from the ink cartridge 8 passes through the liquid supply tube 76, the upper liquid flow path 90, and the lower liquid flow path 93 and protrudes below the pressure adjustment member 14. The ink is discharged from the outflow pipe 48 to the recording head 3 side. On the other hand, the air from the first pump 79 passes through the first liquid supply tube, the first upper gas flow path 91, and the first lower gas flow path 94 in the middle of the lower liquid flow path 93. It is sent to the formed chalk chamber 97. The air from the second pump 80 passes through the second liquid supply tube 78, the second upper gas flow path 92, and the second lower gas flow path 95 in the middle of the lower liquid flow path 93. It is sent to the formed tank chamber 98.

  As shown in FIG. 4, a self-sealing unit 96, a choke chamber 97, and a tank chamber 98 are formed in order from the upstream side in the middle of the lower liquid flow path 93. The self-sealing unit 96 is a kind of negative pressure generating means for maintaining the inside of the lower liquid channel 93 in the pressure adjusting member 14 at a predetermined negative pressure. The self-sealing unit 96 includes, for example, a film (not shown) that seals a part of the flow path inside, and a self-sealing valve (not shown) that is partly fixed to the inner surface of the film. Are preferably employed. Such a self-sealing unit 96 self-seals the film when the internal pressure (specifically, the negative pressure) in the lower liquid flow path 93 is reduced by ejecting ink from the nozzles 24 of the recording head 3. The self-sealing valve is pressed by bending to the valve side. As a result, the self-sealing valve is opened, and the ink from the ink cartridge 8 is supplied to the downstream side (that is, the recording head 3 side) via the lower liquid flow path 93. On the other hand, when ink is introduced from the ink cartridge 8 and the internal pressure of the lower liquid channel 93 rises, the film is bent in a direction away from the self-sealing valve, the self-sealing valve is closed, and the lower liquid channel 93 is closed. That is, the self-sealing unit 96 closes the lower liquid flow path 93 in a normal state, and the negative pressure in the lower liquid flow path 93 reaches a predetermined value due to ink ejection (consumption) by the recording head 3. In this case, the lower liquid flow path 93 is autonomously opened to introduce ink from the ink cartridge 8.

  As shown in FIG. 5, the choke chamber 97 is a space connected to the downstream side of the self-sealing unit 96 via the first connection channel 100 which is a part of the lower liquid channel 93. The downstream end of the first connection channel 100 is opened to a surface (ie, bottom surface) on one side (the lower side in FIG. 5) of the choke chamber 97. A second connection channel 101 that is a part of the lower liquid channel 93 is connected to one surface of the choke chamber 97. The upstream end of the second connection channel 101 has a protruding portion 103 that protrudes in a cylindrical shape from one surface of the choke chamber 97 toward the other surface (the upper surface in FIG. 5) (ie, the ceiling surface). Opened at the tip of the. Furthermore, the downstream end of the first lower gas flow path 94 is opened on the other surface of the choke chamber 97. The choke chamber 97 has a first liquid space 106 in which the first connection channel 100 and the second connection channel 101 communicate with each other, and a first gas space in which the first lower gas channel 94 communicates with the choke chamber 97. A first flexible member 104 made of rubber, a film, or the like that partitions 105 is attached. As a result, the first liquid space 106 partitioned by the first flexible member 104 in the choke chamber 97 becomes a part of the lower liquid flow path 93 through which the liquid flows. The first gas space 105 partitioned by the member 104 becomes a part of the gas flow path through which the gas communicated with the first gas supply tube 77 flows. That is, the liquid channel and the gas channel are in contact with each other with the first flexible member 104 interposed therebetween.

  The first flexible member 104 in the present embodiment is fixed to a surface on one side of the choke chamber 97. The central portion of the first flexible member 104 is biased toward the other surface side of the choke chamber 97 by a first biasing member 107 fixed to the one surface of the choke chamber 97. Further, the first urging member 107 in the present embodiment is wound around the protrusion 103. Thus, in a state where the first gas space 105 is not pressurized (for example, a state where the pressure is close to atmospheric pressure or the atmospheric pressure), the first urging member 107 causes the first urging force to be applied to the first gas space 105. A gap is formed between the flexible member 104 and the tip of the protrusion 103, and the opening of the second connection channel 101 on the choke chamber 97 side is opened. This allows ink to flow into the tank chamber 98 side. On the other hand, when the first gas space 105 is pressurized by driving the first pump 79, the first flexible member 104 is biased by the first biasing member 107 as shown by the broken line in FIG. Against this, it deforms toward the protrusion 103 and abuts against the tip of the protrusion 103. As a result, the opening on the choke chamber 97 side of the second connection channel 101 is closed, and the inflow of ink to the tank chamber 98 side is inhibited. In short, the first flexible member 104 and the first urging member 107 are disposed in the liquid channel upstream of the tank chamber 98 (specifically, the lower liquid channel 93). It functions as an on-off valve that converts between an open state that allows flow and a closed state that obstructs the flow of liquid in the liquid flow path. That is, the first flexible member 104 and the first biasing member 107 correspond to the liquid flow path opening / closing valve in the present invention.

  As shown in FIG. 5, the tank chamber 98 is a space connected to the downstream side of the choke chamber 97 via the second connection channel 101. The downstream end of the second connection channel 101 is opened to a surface (that is, a bottom surface) on one side (lower side in FIG. 5) of the tank chamber 98. Further, a third connection flow path 102 that constitutes a downstream portion of the lower liquid flow path 93 is connected to one surface of the tank chamber 98. Furthermore, the downstream end of the second lower gas flow path 95 is opened on the other side (upper side in FIG. 5) (that is, the ceiling surface) of the tank chamber 98. The tank chamber 98 includes a second liquid space 110 (corresponding to a partial flow path in the present invention) in which the second connection flow path 101 and the third connection flow path 102 communicate with each other, and a second lower gas flow. A second flexible member 108 (corresponding to a flexible member in the present invention) made of rubber, film, or the like that partitions the second gas space 109 through which the passage 95 communicates is attached. As a result, the second liquid space 110 partitioned by the second flexible member 108 in the tank chamber 98 becomes a part of the lower liquid flow path 93 through which the liquid flows, and the second flexible space in the tank chamber 98. The second gas space 109 partitioned by the member 108 becomes a part of the gas flow path through which the gas communicated with the second gas supply tube 78 flows. That is, the liquid channel and the gas channel are in contact with each other with the second flexible member 108 interposed therebetween.

  The second flexible member 108 in this embodiment is fixed to a surface on one side of the tank chamber 98. The central portion of the second flexible member 108 is placed on the other side of the tank chamber 98 by the second biasing member 111 fixed to the opening edge of the third flow path on the one side surface of the tank chamber 98. It is biased to the surface side. Thereby, in a state where the second gas space 109 is not pressurized (for example, a state where the pressure is close to atmospheric pressure or atmospheric pressure), the second urging member 111 causes the second urging member 111 to The flexible member 108 is pressed against the other surface side of the tank chamber 98, and the volume of the second liquid space 110 is increased. On the other hand, when the second gas space 109 is pressurized by driving the second pump 80, the second flexible member 108 is biased by the second biasing member 111 as shown by the broken line in FIG. The volume of the second liquid space 110 is reduced by being pressed against one surface side of the tank chamber 98. That is, if the second flexible member 108 is deformed to the one surface side of the tank chamber 98 by pressurization of the second liquid space 110, the second liquid space 110 becomes the first volume (in FIG. 5). On the other hand, if the second flexible member 108 is deformed to the other surface side of the tank chamber 98 due to the decompression of the second liquid space 110, the second liquid space 110 is changed to the first liquid space 110. The volume is changed to a second volume (see the solid line in FIG. 5) that is larger than the first volume. A series of the second gas supply tube 78 (including the second branch 82), the second upper gas flow path 92, the second lower gas flow path 95, the second gas space 109, and the like. The gas flow path corresponds to the gas flow path in the present invention. The series of gas flow paths and the second pump 80 correspond to the deformation means in the present invention.

  As shown in FIG. 3, the metal shield 16 is a metal member in which a housing space 68 for housing the pressure adjusting member 14 and the circuit board 15 is formed. The metal shield 16 covers the pressure adjusting member 14 and the circuit board 15, the pressure-adjusting member 14 and the circuit board 15 on the upper surface, and the highly rigid metal base 51 to which the plurality of liquid ejecting units 4 are fixed on the lower surface. And a metal cover 52 having a thin plate shape or the like. The metal base 51 is a plate material along the XY plane that is long in the Y direction as shown in FIG. 2, and is grounded by being electrically connected to the ground line G shown in FIG. In the region where the pressure adjusting member 14 of the metal base 51 is fixed, a plurality of base through holes 59 through which the liquid outflow pipes 48 of the pressure adjusting member 14 are inserted are opened in the thickness direction. As shown in FIG. 3, the liquid outflow pipe 48 of the pressure adjusting member 14 is inserted into the base through hole 59 and connected to the liquid ejecting unit 4 (specifically, the liquid introduction port 60).

  Further, a step 54 in which the upper surface of the metal base 51 is lowered by one step is formed at one end (right side in FIGS. 2 and 3) of the metal base 51 in the X direction. As shown in FIG. 2, a circuit board fixing screw hole 55 is formed on the side surface of the step 54. Accordingly, the circuit board 15 is fixed through the substrate through hole 56 formed in the circuit board 15 in a state where the circuit board 15 is placed on the upper surface of the step 54 along the side surface (that is, the YZ plane) of the step 54. The circuit board 15 is fixed to the metal base 51 by fixing the circuit board fixing screw 57 in the screw hole 55. Note that the circuit board fixing screw 57 electrically connects the wiring at the installation potential in the circuit board 15 and the metal base 51.

  The metal cover 52 is a metal cover member that is long in the Y direction and is formed so as to cover the pressure adjusting member 14 and the circuit board 15 with a space therebetween. That is, as shown in FIG. 3, the metal cover 52 is attached to the metal base 51 to form an accommodation space 68 with the metal base 51. Specifically, the metal cover 52 is formed in a stepped shape that is one step down from the upper surface 65 along the XY plane that covers the upper surface of the pressure adjusting member 14 and from one end of the upper surface 65 in the X direction. The upper surface stepped portion 67 and two side surfaces 66 facing each other along the YZ plane are provided. A cover through hole 71 is formed in the lower end portion of the side surface 66 of the metal cover 52 so as to penetrate the side surface 66 in the thickness direction. A metal cover fixing screw hole 70 formed on a side surface in the short direction (X direction) of the metal base 51 (that is, a surface facing the side surface 66 of the metal cover 52) through the cover through hole 71 is used for fixing the metal cover. By fixing the screw 72, the side surface 66 of the metal cover 52 is fixed to the metal base 51. Further, a first cover opening 73 through which the liquid outlet 42 of the flow path member 13 is inserted and a second cover opening 74 through which the gas outlet 44 of the flow path member 13 is inserted into the upper surface 65 of the metal cover 52. Is formed. Further, a third cover opening 75 through which the wiring member 11 is inserted is formed in the upper surface stepped portion 67 of the metal cover 52. The wiring member 11 is inserted through the third cover opening 75 and connected to the circuit board 15.

  The liquid ejecting unit 4 in the present embodiment is fixed to the lower surface of the metal base 51 (that is, the surface on the medium support portion 6 side) in the Y direction in a state where the relative positions are defined, and fixed by screws or an adhesive. Yes. As shown in FIG. 2, each liquid ejecting unit 4 has a flow in which a plurality of unit heads 83 (also referred to as head chips) and a supply channel (not shown) through which ink supplied to each unit head 83 flows. A path structure 84 and a protective plate 85 for protecting each unit head 83 are provided. As will be described later, the unit head 83 includes a nozzle plate 23 in which the nozzles 24 are established, a substrate on which a flow path communicating with the nozzles 24 is formed, an actuator unit 17 that is a drive source for ejecting (discharging) ink, and the like. The constituent members are stacked. The unit head 83 has a substantially parallelogram shape that is long in the nozzle row direction (Xa direction) in a plan view from the lower surface of the nozzle plate 23 (that is, the nozzle surface 23a). In the present embodiment, a total of six unit heads 83 are arranged in each liquid ejecting unit 4 along the Y direction, which is the juxtaposed direction of the liquid ejecting units 4, and a total of two strips are disposed on one unit head 83. Nozzle rows are provided. Accordingly, twelve nozzle rows are arranged in parallel in each liquid ejecting unit 4.

  The protection plate 85 is a metal plate-like plate material common to the unit heads 83 provided in the liquid ejecting unit 4. In the protective plate 85, nozzle exposure openings 86 that expose the nozzles 24 formed on the nozzle plate 23 are opened at positions corresponding to the nozzle plate 23 of each unit head 83. The nozzle exposure opening 86 in the present embodiment has a parallelogram shape that is long in the nozzle row direction (Xa direction). Each unit head 83 is joined to the upper surface of the protective plate 85 (the surface opposite to the medium support portion 6 side) with an adhesive in a state where the nozzle 24 is exposed to the corresponding nozzle exposure opening 86.

  The flow path structure 84 is a member formed by laminating a plurality of members that distribute and supply the ink sent from the ink cartridge 8 to each unit head 83 joined to the lower surface side of the flow path structure 84. is there. A plurality of liquid introduction ports 60 are opened on the upper surface of the flow channel structure 84, and ink is introduced from the liquid introduction ports 60 into the internal flow channel. In the present embodiment, four liquid inlets 60 are provided in the flow path structure 84 corresponding to the total four ink colors. Filters (not shown) are respectively disposed in the middle of the supply flow paths corresponding to the respective colors inside the flow path structure 84 to remove bubbles and foreign matters from the ink flowing through the supply flow paths. Each supply channel is branched into a number of branch channels corresponding to the number of unit heads 83 provided in the liquid ejecting unit 4 inside the channel structure 84, and the liquid introduction channels 21 of the plurality of unit heads 83. Communicate with.

  As shown in FIG. 6, the unit head 83 in this embodiment is attached to the head case 19 in a state where the actuator unit 17 and the flow path unit 18 are stacked.

  The head case 19 in the present embodiment is a box-shaped member made of synthetic resin. As shown in FIG. 6, an actuator housing space 20 and a penetrating space 22, which are long spaces along the nozzle row direction, are formed at the center of the head case 19. The actuator housing space 20 is a space in which the actuator unit 17 is housed, and is recessed from the lower surface of the head case 19 to the middle of the plate thickness direction (that is, the direction orthogonal to the lower surface) by the thickness of the actuator unit 17. Is formed. The through space 22 communicates with the ceiling surface on the upper surface side of the actuator housing space 20 and is formed in a state of penetrating the head case 19 in the plate thickness direction. A flexible substrate 35 that supplies a drive signal to a piezoelectric element 32 (described later) is disposed in the through space 22 and the actuator housing space 20. Although not shown, the flexible substrate 35 extends from the upper surface opening of the through space 22 to the outside of the unit head 83 and is connected to a collective substrate provided in the flow path structure 84. The assembly board is connected to the circuit board 15 via a cable (not shown). For example, this cable is connected to the circuit board 15 through a gap between the metal base 51 and the metal cover 52. As shown in FIG. 6, a liquid introduction path 21 through which ink flows is formed in the head case 19. The lower end of the liquid introduction path 21 is connected to a common liquid chamber 26 described later. In the present embodiment, two liquid introduction paths 21 are formed corresponding to the nozzle rows formed in two rows.

  A flow path unit 18 is connected to the lower surface of the head case 19. The flow path unit 18 is a long substrate along the nozzle row direction in which the communication substrate 25, the nozzle plate 23, and the compliance substrate 37 are laminated. The communication substrate 25 is a substrate manufactured from, for example, a silicon single crystal substrate. As shown in FIG. 6, the communication substrate 25 communicates with the liquid introduction path 21, stores a common liquid chamber 26 in which ink common to the pressure chambers 30 is stored, and inks from the common liquid chamber 26. An individual communication path 27 that individually supplies the pressure chamber 30 and a nozzle communication path 28 that connects the pressure chamber 30 and the nozzle 24 are formed by anisotropic etching. The common liquid chambers 26 are long empty portions along the nozzle row direction, and are formed in two rows corresponding to the liquid introduction paths 21. A plurality of the individual communication passages 27 and the nozzle communication passages 28 are formed along the direction in which the pressure chambers 30 are arranged in parallel (in other words, the nozzle row direction).

  The nozzle plate 23 is a silicon substrate (for example, a silicon single crystal substrate) bonded to the lower surface of the communication substrate 25 (that is, the surface opposite to the pressure chamber forming substrate 29). The nozzle plate 23 of the present embodiment is joined to a region that is out of the compliance substrate 37 so as not to overlap the compliance substrate 37. In other words, the nozzle plate 23 is joined to a central region that is out of the opening on the lower surface side of the common liquid chamber 26 of the communication substrate 25. In the nozzle plate 23, a plurality of nozzles 24 are provided in a straight line shape (in other words, in a line shape) along the longitudinal direction of the nozzle plate 23. That is, a nozzle row composed of a plurality of nozzles 24 is formed. The plurality of nozzles 24 (that is, nozzle rows) arranged in parallel are provided at equal intervals from the nozzle 24 on one end side to the nozzle 24 on the other end side at a pitch corresponding to the dot formation density. The lower surface of the nozzle plate 23 (the surface opposite to the communication substrate 25) is a nozzle surface 23a in which the nozzles 24 are opened. A liquid repellent film 113 having liquid repellency with respect to ink is formed on the nozzle surface 23a (see FIG. 9 and the like). The nozzle surface in the present invention is a concept including not only the nozzle surface 23a but also the lower surface of the protective plate 85. Note that a configuration in which the protective plate 85 is not provided in the liquid ejecting unit may be employed, and in such a configuration, the lower surface of the nozzle plate becomes the nozzle surface.

  As shown in FIG. 9 and the like, the nozzle 24 in the present embodiment is formed on the first nozzle portion 115 formed on the lower side (that is, the side opposite to the pressure chamber 30) and on the upper side (the pressure chamber 30 side). In addition, the second nozzle portion 116 has a two-stage structure. The inner surface of the first nozzle portion 115 has a cylindrical shape with a constant inner diameter. On the other hand, the inner surface of the second nozzle portion 116 has a tapered shape that is inclined so that the inner diameter of the second nozzle portion 116 increases from the first nozzle portion 115 side toward the opposite side of the first nozzle portion 115. ing. Note that the inner surface of the second nozzle portion 116 may have a cylindrical shape with a constant inner diameter larger than that of the first nozzle portion 115. Here, the liquid repellent film 113 formed on the nozzle surface 23 a extends to the lower end portion of the inner surface of the first nozzle portion 115. That is, the lower end portion of the inner surface of the first nozzle portion 115 is a liquid repellent region N1 in which the liquid repellent film 113 is formed (see FIG. 9). On the other hand, the remaining part of the inner surface of the first nozzle part 115 and the second nozzle part 116 are not formed with the liquid repellent film 113, and are lyophilic regions N2 having lyophilicity with respect to the ink (FIG. 9). In short, in the present embodiment, the inner surface of the nozzle 24 is, in order from the end opposite to the pressure chamber 30, a liquid repellent region N1 having liquid repellency with respect to ink and a lyophilic liquid having lyophilicity with respect to ink. And an area N2.

  The compliance substrate 37 is a flexible substrate bonded to the lower surface of the communication substrate 25 and corresponding to the common liquid chamber 26. That is, the compliance substrate 37 is bonded to a region of the communication substrate 25 that is not covered with the nozzle plate 23. The compliance substrate 37 in the present embodiment is a plate material in which a sealing film 39 having low rigidity and flexibility is laminated on a fixed substrate 38 made of a hard material such as metal. A region of the fixed substrate 38 that faces the common liquid chamber 26 is an opening that is removed in the thickness direction. For this reason, the lower surface of the common liquid chamber 26 is sealed only with the sealing film 39 and functions as a compliance section that absorbs pressure fluctuations of the ink in the common liquid chamber 26.

  As shown in FIG. 6, the actuator unit 17 in this embodiment is a composite substrate in which substrates such as a pressure chamber forming substrate 29, a vibration plate 31, and a sealing plate 33 are stacked. The actuator unit 17 is formed in a size that can be accommodated in the actuator accommodating space 20 of the head case 19, and is accommodated in the actuator accommodating space 20.

  The pressure chamber forming substrate 29 is a substrate manufactured from, for example, a silicon single crystal substrate. A part of the pressure chamber forming substrate 29 is completely removed in the plate thickness direction by anisotropic etching or the like, and a plurality of spaces to be the pressure chambers 30 are arranged in parallel along the nozzle row direction. The space is partitioned by the communication substrate 25 on the lower side and partitioned by the diaphragm 31 to form the pressure chamber 30. Further, this space, that is, the pressure chamber 30 is formed long in a direction orthogonal to the nozzle row direction, and the individual communication path 27 communicates with one end portion in the longitudinal direction, and the nozzle is formed at the other end portion. The communication path 28 communicates. In addition, a plurality of pressure chambers 30 in the present embodiment are formed along the nozzle row direction.

The diaphragm 31 is formed on, for example, an elastic film made of silicon dioxide (SiO ₂ ) formed on the upper surface of the pressure chamber forming substrate 29 (that is, the surface opposite to the communication substrate 25 side). And a thin film member made of an insulating film made of zirconium dioxide (ZrO ₂ ). The diaphragm 31 seals the upper opening of the space to be the pressure chamber 30. In other words, the upper surface of the pressure chamber 30 is partitioned by the diaphragm 31. A portion of the diaphragm 31 corresponding to the pressure chamber 30 (specifically, an upper opening of the pressure chamber 30) functions as a displacement portion that displaces in a direction away from or close to the nozzle 24 as the piezoelectric element 32 is bent and deformed. To do. That is, a region corresponding to the upper opening of the pressure chamber 30 in the diaphragm 31 is a drive region where bending deformation is allowed. The volume of the pressure chamber 30 changes due to the deformation (displacement) of the drive region (displacement portion). On the other hand, a region of the diaphragm 31 that is out of the upper opening of the pressure chamber 30 is a non-driving region in which bending deformation is hindered.

  Areas corresponding to the pressure chambers 30 (that is, driving areas) on the upper surface of the diaphragm 31 (specifically, the insulator film of the diaphragm 31) (that is, the surface of the diaphragm 31 opposite to the pressure chamber forming substrate 29). The piezoelectric elements 32 are respectively stacked. The piezoelectric element 32 in the present embodiment is a so-called flexural mode piezoelectric element. A plurality of the piezoelectric elements 32 are arranged in parallel along the nozzle row direction corresponding to each nozzle 24. Each piezoelectric element 32 is formed by sequentially laminating, for example, a lower electrode layer serving as an individual electrode, a piezoelectric layer, and an upper electrode layer serving as a common electrode in order from the vibration plate 31. Note that the lower electrode layer can be a common electrode and the upper electrode layer can be an individual electrode depending on the convenience of the drive circuit and wiring. The piezoelectric element 32 configured as described above bends and deforms in a direction away from or close to the nozzle 24 when an electric field corresponding to the potential difference between both electrodes is applied between the lower electrode layer and the upper electrode layer.

  As shown in FIG. 5, the sealing plate 33 is a substrate on which a piezoelectric element accommodation space 34 that can accommodate the piezoelectric elements 32 is formed. The sealing plate 33 is joined to the vibration plate 31 in a state where the piezoelectric element 32 is accommodated in the piezoelectric element accommodation space 34. In the present embodiment, two rows of piezoelectric element accommodating spaces 34 are formed corresponding to the rows of piezoelectric elements 32 formed in two rows. A connection space 36 is formed between the two piezoelectric element accommodation spaces 34 in which the sealing plate 33 is removed in the thickness direction. The connection space 36 communicates with the through space 22, and an end portion of the flexible substrate 35 inserted into the through space 22 is disposed therein. In the connection space 36, the flexible substrate 35 and lead wiring (not shown) extending from the piezoelectric element 32 are connected.

  The recording head 3 formed as described above is supplied with ink from the ink cartridge 8 through the liquid flow paths formed in the flow path member 13, the pressure adjustment member 14, and the flow path structure 84. Thus, ink is supplied to the pressure chamber 30 in each unit head 83. The unit head 83 changes the volume of the pressure chamber 30 by supplying a drive signal from the control unit to the piezoelectric element 32 in a state where the pressure chamber 30 is filled with ink. Ink droplets are ejected from the nozzles 24 communicating with the pressure chambers 30 via the nozzle communication passages 28 by utilizing the pressure fluctuation of the ink in the pressure chambers 30 due to the change in volume. A series of liquid channels including the upper liquid channel 90, the lower liquid channel 93, the channel in the channel structure 84, the liquid introduction channel 21, the common liquid chamber 26, the individual communication channel 27, etc. This corresponds to the liquid channel in the present invention.

  Next, the wiping operation in this embodiment will be described. 7 to 9 are schematic diagrams for explaining a series of wiping operations from the normal state (the state in which liquid can be ejected) to wiping the nozzle surface 23a and returning to the normal state again. In a normal state before performing the wiping operation, the first pump 79 and the second pump 80 are not driven, and the first valve 87 and the second valve 88 are opened. Therefore, the first gas space 105 in the choke chamber 97 and the second gas space 109 in the tank chamber 98 are at atmospheric pressure, and the first liquid space 106 and the second liquid space 110 in the tank chamber 98 are expanded. It has become. That is, the first flexible member 104 is opened to allow ink to flow from the self-sealing unit 96 to the tank chamber 98, and the volume of the second liquid space 110 is larger than the first volume. It has a large second volume. In this state, as shown in FIG. 9, the pressure in the pressure chamber 30 is maintained at a negative pressure (specifically, the first pressure lower than the atmospheric pressure), so that the meniscus M in the nozzle 24 is It is located in the lyophilic region N2 that is off the liquid repellent film 113 of the one nozzle portion 115. If the nozzle surface 23 a is wiped in this state, there is a possibility that bubbles are drawn into the nozzle 24. Therefore, in the wiping operation in the present embodiment, the nozzle surface 23a is wiped in a state where the pressure chamber 30 is pressurized and the negative pressure is released. The wiping operation is performed, for example, when the printing operation on the recording medium 2 is completed or after a predetermined time has elapsed.

  Specifically, first, the first valve 87 is closed, the first pump 79 is driven, and the first gas on the upstream side (first flexible member 104 side) from the first valve 87. The inside of a series of gas flow paths composed of the supply tube, the first upper gas flow path 91, the first lower gas flow path 94, the first gas space 105, and the like is pressurized. As a result, the first flexible member 104 is deformed to the protruding portion 103 side against the urging force of the first urging member 107 and is closed, and ink from the self-sealing unit 96 to the tank chamber 98 is closed. Inflow is inhibited. Next, the second valve 88 is closed, the second pump 80 is driven, and the second gas supply tube 78 upstream of the second valve 88 (second flexible member 108 side), The inside of a series of gas flow paths including the second upper gas flow path 92, the second lower gas flow path 95, the second gas space 109, and the like is pressurized. As a result, the second flexible member 108 is deformed to the bottom surface side of the tank chamber 98 against the urging force of the second urging member 111, and the volume of the second liquid space 110 is changed from the second volume. The first volume is smaller than the second volume (see the broken line in FIG. 5). As a result, the liquid flow path downstream of the second liquid space 110 is pressurized at the first speed from the first pressure to the second pressure higher than the atmospheric pressure, and the negative pressure in the pressure chamber 30 is reduced. The pressure is released. As a result, as shown in FIG. 7, the ink I overflowed from the nozzle 24 (more specifically, the first nozzle portion 115) (that is, the ink I protruded below the nozzle surface 23a (the recording medium 2 side)). State). In this state, the nozzle surface 23a is wiped by the wiper 9.

  Specifically, when the negative pressure in the pressure chamber 30 is released, the wiper 9 is moved to the lower side of the nozzle surface 23a by a driving mechanism (not shown), and is moved toward the nozzle surface 23a side. 23a. Then, the wiper 9 is moved (or slid) in, for example, a direction along the nozzle row direction by the driving mechanism to wipe the nozzle surface 23a. At this time, since the negative pressure in the pressure chamber 30 is released, the problem that bubbles are drawn into the nozzle 24 can be suppressed. If the nozzle surface 23a is wiped off by the wiper 9, the wiper 9 is separated from the nozzle surface 23a by the drive mechanism. Next, the cap 10 is moved to a position below the nozzle surface 23a by a driving mechanism (not shown), and is moved toward the nozzle surface 23a so as to contact the nozzle surface 23a. As a result, as shown in FIG. 8, each nozzle 24 is covered with the cap 10, in other words, each nozzle 24 is sealed in the sealing space of the cap 10. In this state, the pressure in the pressure chamber 30 is returned to the negative pressure.

  Specifically, the driving of the first pump 79 is stopped, the first valve 87 is opened, the first gas supply tube 77, the first upper gas flow path 91, the first lower gas flow A series of gas flow paths including the path 94 and the first gas space 105 are opened to the atmosphere. As a result, the inside of the first gas space 105 is depressurized, the first flexible member 104 is deformed to the opposite side to the protruding portion 103 and is opened, and the ink from the self-sealing unit 96 to the tank chamber 98 is discharged. Inflow is allowed. In this state, the driving of the second pump 80 is stopped, the second valve 88 is opened, the second gas supply tube 78, the second upper gas flow path 92, and the second lower gas flow path. 95 and the second gas space 109 and the like are opened to the atmosphere via a resistance applying unit 89. Thereby, the inside of the second gas space 109 is gently depressurized, the second flexible member 108 is deformed to the ceiling surface side of the second tank chamber 98, and the volume of the second liquid space 110 is the first. From the first volume to the second volume larger than the first volume. With this change, the meniscus M of the nozzle 24 moves toward the back side of the nozzle 24 (that is, the pressure chamber 30 side) (see the arrow in FIG. 8). When the volume of the second liquid space 110 returns to the second volume, the pressure in the pressure chamber 30 returns to the negative pressure, and the meniscus M of the nozzle 24 is in a normal state (a state where ink can be ejected). (See FIG. 9). Here, when the second gas space 109 is opened to the atmosphere without using the resistance applying unit 89, the volume of the second liquid space 110 rapidly changes from the first volume to the second volume, and the pressure chamber 30. The inside is also rapidly depressurized. As a result, the meniscus is drawn into the back of the nozzle 24 (the second nozzle portion 116 or the back side), and normal injection cannot be performed, or the meniscus cannot be returned to a position where normal injection can be performed, That is, the meniscus may be destroyed. On the other hand, in the present embodiment, the second gas space 109 is opened to the atmosphere (that is, the pressure is reduced) via the resistance applying unit 89, so that the second volume from the first volume of the second liquid space 110 is increased to the second. The change to the volume is made gentle so that the meniscus is not destroyed.

  That is, by adjusting the resistance in the resistance applying unit 89, the rate of change in the volume of the second liquid space 110 that changes from the first volume to the second volume does not exceed the rate at which the meniscus of the nozzle 24 is destroyed. Thus, the deformation speed of the second flexible member 108 is adjusted. Specifically, the change rate of the volume of the second liquid space 110 that changes from the first volume to the second volume is the volume of the second liquid space 110 that is changed before the nozzle surface 23a is wiped. Make it slower than the rate of change. In other words, the change rate of the volume of the second liquid space 110 that changes from the second volume to the first volume before the nozzle surface 23a is wiped is changed from the first volume to the second volume after the nozzle surface 23a is wiped. The second flexible member 108 is deformed so as to be faster than the rate of change of the volume of the second liquid space 110 that changes to the volume. Thus, in a series of liquid flow paths including the upper liquid flow path 90, the lower liquid flow path 93, the flow path in the flow path structure 84, the liquid introduction path 21, the common liquid chamber 26, the individual communication path 27, and the like. Is reduced from the second pressure to the first pressure at a second speed that is slower than the first speed. As a result, as shown in FIG. 9, the meniscus M of the nozzle 24 is returned to the normal state.

  By the way, even if the rate of change from the first volume to the second volume of the second liquid space 110 is too slow, there are the following problems. That is, if the change in the volume of the second liquid space 110 is too slow, the amount of movement of the meniscus accompanying the change in the volume of the second liquid space 110 decreases, and the meniscus reaches the lyophilic region N2 of the first nozzle portion. There is a possibility that the liquid repellent region 113 is formed in the liquid repellent region N1 without returning. As a result, there is a possibility that the meniscus shape becomes an abnormal shape in which normal injection cannot be performed. For this reason, the volume of the second liquid space 110 is changed from the first volume to the second volume at such a speed that the meniscus of the nozzle 24 moves from the liquid repellent area N1 side of the first nozzle section 115 to the lyophilic area N2. It is desirable to change to In short, by adjusting the resistance in the resistance applying portion 89, the meniscus M (more specifically, the end portion of the meniscus M in contact with the inner wall surface in the nozzle 24) becomes the parent of the first nozzle portion 115 as shown in FIG. The change rate of the volume of the second liquid space 110 is adjusted so as to return to the liquid region N2. For example, the resistance in the resistance applying unit 89 is adjusted so that the volume of the second liquid space 110 changes from the first volume to the second volume over a period of 5 seconds to 10 seconds. As a result, when the pressure in the series of liquid flow paths in the recording head 3 is returned to negative pressure, the meniscus is returned to an appropriate position in the nozzle 24. That is, it can suppress that a meniscus is destroyed.

  Thus, when the series of liquid flow paths in the recording head 3 and the pressure chamber 30 are returned to the negative pressure, the cap 10 is separated from the nozzle surface 23a by the driving mechanism, and the wiping operation is finished. In the normal state in the present embodiment, the first valve 87 and the second valve 88 are opened, and the first gas space 105 and the second gas space 109 are opened to the atmosphere. This is not a limitation. The first valve 87 and the second valve 88 may be closed, and the first gas space 105 and the second gas space 109 may be separated from the atmosphere. In this way, even if the surrounding environment changes, it is possible to prevent the first flexible member 104 and the second flexible member 108 from being deformed accordingly. In the wiping operation of the present embodiment, the pressure in the pressure chamber 30 is returned to the negative pressure while the nozzle surface 23a is sealed with the cap 10, but the present invention is not limited to this. The pressure in the pressure chamber 30 may be returned to the negative pressure in a state where the nozzle 24 is exposed to the atmosphere without sealing the nozzle surface 23 a with the cap 10.

  Then, by performing the wiping operation as described above, when the wiper 9 wipes the nozzle surface 23a, it is possible to suppress a problem that bubbles are drawn into the nozzle 24. In particular, in the present embodiment, since the second pump 80 is driven in a state where the second valve 88 is in the closed state, a series of operations including the second gas space 109 without passing through the resistance applying unit 89. The inside of the gas channel can be pressurized. Thereby, the inside of this gas channel can be pressurized efficiently. In addition, when the inside of the second gas space 109 is pressurized, the first flexible member 104 is in a closed state, so that the pressure fluctuation accompanying the change in the volume is generated in the liquid flow path upstream of the tank chamber 98. Propagation can be suppressed. Thereby, the inside of the pressure chamber 30 can be pressurized efficiently. Further, in the present embodiment, the rate of change of the volume of the second liquid space 110 before wiping the nozzle surface 23a is faster than the rate of change of the volume of the second liquid space 110 after wiping the nozzle surface 23a. Therefore, the pressurizing operation for pressurizing the inside of the pressure chamber 30 can be accelerated. As a result, the operation time of the wiping operation can be shortened. In this case, even if the change rate of the volume of the second liquid space 110 before wiping the nozzle surface 23a exceeds the speed at which the meniscus in the nozzle 24 is destroyed, the nozzle surface 23a is wiped by the wiper 9 thereafter. By doing so, the meniscus can be formed at an appropriate position in the nozzle.

  On the other hand, after wiping the nozzle surface 23a, when the pressure in the liquid flow path in the recording head 3 is reduced from the second pressure to the first pressure, the pressure reduction speed is reduced. It can be delayed, and the meniscus in the nozzle 24 can be prevented from being destroyed. In particular, in the present embodiment, by reducing the pressure of the second gas space 109 via the resistance applying unit 89, the pressure reduction speed in the series of gas flow paths including the second gas space 109 is reduced. Compared with the case where the pressure in a series of gas flow paths including the second gas space 109 is managed using an atmospheric pressure sensor or the like, the configuration is simplified. Further, in the present embodiment, since the liquid flow path in the recording head 3 is depressurized while the nozzle 24 is covered with the cap 10, it is possible to suppress the ink in the nozzle 24 from being thickened. Further, since the volume of the second gas space 109 is changed so that the meniscus moves from the liquid repellent area N1 side of the first nozzle portion 115 to the lyophilic area N2, the meniscus is moved to an appropriate position in the nozzle 24. Can be restored. As a result, ejection failure in which ink is not ejected normally can be suppressed, and as a result, the reliability of the printer 1 can be improved. In addition, when the volume of the second liquid space 110 is changed from the first volume to the second volume, the first flexible member 104 is in an open state. By supplying the liquid, it is possible to prevent the meniscus from being drawn too far into the nozzle 24. As a result, the meniscus in the nozzle 24 can be further prevented from being destroyed. Further, the pressure fluctuation in the liquid flow path caused by the opening / closing operation of the first flexible member 104 can be absorbed by the second flexible member 108 of the tank chamber 98. Thereby, destruction and deformation | transformation of the said meniscus by this pressure fluctuation | variation propagating to the meniscus in the nozzle 24 can be suppressed. As a result, the opening / closing operation of the first flexible member 104 can be accelerated.

  By the way, in the above-described embodiment, the configuration in which the first flexible member 104 and the first urging member 107 are provided in the choke chamber 97 as the liquid flow path opening / closing valve is employed. In short, any configuration is possible as long as the liquid flow path between the tank chamber and the self-sealing unit can be opened and closed. In the above-described embodiment, as the deformation means for deforming the second flexible member 108, the second gas supply tube 78, the second upper gas flow path 92, the second lower gas flow path 95, and Although a series of gas flow paths composed of the second gas space 109 and the like and the second pump for pressurizing the inside of the gas flow path are exemplified, the present invention is not limited to this. For example, an eccentric cam for deforming the second flexible member is provided in the second gas space, and the second flexible member is deformed by driving the eccentric cam to increase the volume of the second liquid space. It may be changed. In this case, the changing speed from the first volume of the second liquid space to the second volume is slower than the changing speed of the second liquid space from the second volume to the first volume. It controls the drive of the eccentric cam as the deformation means. Furthermore, in the above-described embodiment, the line head including a plurality of liquid ejecting units 4 is exemplified as the recording head 3, but is not limited thereto. The present invention can also be applied to a so-called serial head that ejects ink while scanning (reciprocating) in a direction orthogonal to the conveyance direction of the recording medium, and a liquid ejecting apparatus including the so-called serial head.

  In the above description, the ink jet recording head 3 has been described as an example of the liquid ejecting head, but the present invention can also be applied to other liquid ejecting heads. For example, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an electrode material ejecting head used for forming an electrode such as an organic EL (Electro Luminescence) display, FED (surface emitting display), a biochip (biochemical element) The present invention can also be applied to bioorganic matter ejecting heads and the like used in the production of In a color material ejecting head for a display manufacturing apparatus, a solution of each color material of R (Red), G (Green), and B (Blue) is ejected as a kind of liquid. Further, an electrode material ejecting head for an electrode forming apparatus ejects a liquid electrode material as a kind of liquid, and a bioorganic matter ejecting head for a chip manufacturing apparatus ejects a bioorganic solution as a kind of liquid.

  DESCRIPTION OF SYMBOLS 1 ... Printer, 2 ... Recording medium, 3 ... Recording head, 4 ... Liquid ejecting unit, 5 ... Conveyance mechanism, 6 ... Medium support part, 7 ... Apparatus main body, 8 ... Ink cartridge, 9 ... Wiper, 10 ... Cap, 11 DESCRIPTION OF SYMBOLS ... Wiring member, 12a ... 1st conveyance roller, 12b ... 2nd conveyance roller, 13 ... Channel member, 14 ... Pressure adjusting member, 15 ... Circuit board, 16 ... Metal shield, 17 ... Actuator unit, 18 ... Flow Path unit, 19 ... head case, 20 ... actuator housing space, 21 ... liquid introduction path, 22 ... penetrating space, 23 ... nozzle plate, 23a ... nozzle surface, 24 ... nozzle, 25 ... communication substrate, 26 ... common liquid chamber, 27 ... Individual communication path, 28 ... Nozzle communication path, 29 ... Pressure chamber forming substrate, 30 ... Pressure chamber, 31 ... Vibration plate, 32 ... Piezoelectric element, 33 ... Sealing plate, 34 ... Piezoelectric element Storage space, 35 ... Flexible substrate, 36 ... Connection space, 37 ... Compliance substrate, 38 ... Fixed substrate, 39 ... Sealing film, 41 ... Liquid supply tube connection part, 42 ... Liquid outlet, 43 ... Gas supply tube connection part , 44 ... Gas outlet, 46 ... Liquid inlet, 47 ... Gas inlet, 48 ... Liquid outlet pipe, 51 ... Metal base, 52 ... Metal cover, 54 ... Step, 55 ... Screw hole for fixing the circuit board, 56 ... Substrate through hole, 57 ... Screw for fixing circuit board, 59 ... Base through hole, 60 ... Liquid inlet, 65 ... Upper surface, 66 ... Side surface, 67 ... Upper surface stepped portion, 68 ... Housing space, 70 ... Metal cover fixing screw Hole: 71 ... Cover through hole, 72 ... Metal cover fixing screw, 73 ... First cover opening, 74 ... Second cover opening, 75 ... Third cover opening, 76 ... Liquid supply tube, 77 ... First Gas supply Tube, 78 ... second gas supply tube, 79 ... first pump, 80 ... second pump, 81 ... first branch path, 82 ... second branch path, 83 ... unit head, 84 ... flow path Structure: 85 ... Protective plate, 86 ... Nozzle exposure opening, 87 ... First valve, 88 ... Second valve, 89 ... Resistance applying portion, 90 ... Upper liquid flow path, 91 ... First upper gas flow path , 92 ... second upper gas flow path, 93 ... lower liquid flow path, 94 ... first lower gas flow path, 95 ... second lower gas flow path, 96 ... self-sealing unit, 97 ... choke chamber, DESCRIPTION OF SYMBOLS 98 ... Tank chamber, 100 ... 1st connection flow path, 101 ... 2nd connection flow path, 102 ... 3rd connection flow path, 103 ... Projection part, 104 ... 1st flexible member, 105 ... 1st Gas space, 106 ... first liquid space, 107 ... first biasing member, 108 ... second flexible member, 109 ... Second gas space, 110 ... Second liquid space, 111 ... Second biasing member, 113 ... Liquid repellent film, 115 ... First nozzle part, 116 ... Second nozzle part

Claims (10)

A liquid ejecting head including a nozzle opened on a nozzle surface, a pressure chamber communicating with the nozzle, and a liquid flow path for supplying a liquid to the pressure chamber;
A part of the liquid flow path is partitioned, and provided with a flexible member that can be deformed by driving the deformation means,
When the flexible member is deformed to change the volume of the partial flow path partitioned by the flexible member in the liquid flow path from the first volume to a second volume larger than the first volume. The liquid ejecting head is characterized in that the flexible member is deformed so that the changing speed of the volume of the partial flow path does not exceed the speed at which the meniscus of the nozzle is destroyed.   The liquid jet head according to claim 1, wherein the volume of the partial flow path is changed from the first volume to the second volume in a state where the nozzle is covered with a cap. The inner surface of the nozzle includes a liquid repellent area having liquid repellency with respect to the liquid and a lyophilic area having liquid affinity with the liquid in order from the end opposite to the pressure chamber. ,
The volume of the partial flow path is changed from the first volume to the second volume so that the meniscus of the nozzle moves from the liquid repellent area side to the lyophilic area. The liquid ejecting head according to claim 2.   When the volume of the partial flow path is changed from the second volume to the first volume and then changed from the first volume to the second volume, the second volume is changed to the first volume. The flexible member is configured such that the rate of change of the volume of the partial flow path that changes to the volume of the partial flow path is faster than the speed of change of the volume of the partial flow path that changes from the first volume to the second volume. The liquid ejecting head according to claim 1, wherein the liquid ejecting head is deformed.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1. A gas flow path in contact with the liquid flow path across the flexible member;
The gas flow path includes a resistance applying unit that provides resistance to the flowing gas,
Depressurizing the inside of the gas flow path via the resistance applying portion, thereby deforming the flexible member to change the volume of the partial flow path from the first volume to the second volume. The liquid ejecting apparatus according to claim 5. A pressurizing mechanism for pressurizing the inside of the gas flow path;
In the gas flow path between the flexible member and the resistance applying portion, an open state that allows a gas flow in the gas flow path, and a closed state that inhibits a gas flow in the gas flow path A gas flow path opening / closing valve that can be converted into
When changing the volume of the partial flow path from the second volume to the first volume, the gas flow path opening / closing valve is closed and the pressurizing mechanism is more flexible than the gas flow path opening / closing valve. When the flexible member is deformed by pressurizing the inside of the gas flow path on the member side, and the volume of the partial flow path is changed from the second volume to the first volume, the gas flow path opening / closing valve The liquid ejecting apparatus according to claim 6, wherein the flexible member is deformed by opening the gas passage and reducing the pressure in the gas flow path through the resistance applying portion. A wiper for wiping the nozzle surface;
8. The liquid ejection according to claim 5, wherein the wiper wipes the nozzle surface in a state where the volume of the partial flow path is changed to the first volume. 9. apparatus. In the liquid channel upstream of the partial channel, a liquid that can be converted into an open state that allows the flow of liquid in the liquid channel and a closed state that blocks the flow of liquid in the liquid channel It has a channel open / close valve,
The liquid flow path opening / closing valve is closed to change the volume of the partial flow path from the second volume to the first volume, while the liquid flow path opening / closing valve is opened to open the partial flow path. The liquid ejecting apparatus according to claim 5, wherein the volume of the liquid is changed from the first volume to the second volume. A nozzle opened on a nozzle surface, a pressure chamber communicating with the nozzle, a liquid ejecting head including a liquid flow path for supplying a liquid to the pressure chamber, and a flexible member that partitions a part of the liquid flow path A control method of a liquid ejecting apparatus comprising: a gas flow channel in contact with the liquid flow channel, a pressurizing mechanism for pressurizing the gas flow channel, and a wiper for wiping the nozzle surface,
By pressurizing the inside of the gas channel by the pressurizing mechanism, the inside of the liquid channel is pressurized at a first speed from a first pressure to a second pressure, and the nozzle surface is moved by the wiper in this pressurized state. A method of controlling a liquid ejecting apparatus, comprising: after wiping, reducing the pressure in the liquid flow path from the second pressure to the first pressure at a second speed slower than the first speed.

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