JP2013193001A - Liquid supply device, liquid discharge device, and liquid supply method - Google Patents

Abstract

A liquid supply device, a liquid discharge device, and a liquid supply method capable of supplying a constant amount of liquid with a minute supply amount are provided.
A liquid supply device 30 supplies air to a syringe 112, a piston 113, and a pressure adjustment chamber 115 and discharges air from the pressure adjustment chamber 115, and supplies and discharges air pressure to the pressure adjustment chamber 115. Supply / discharge means that presses the liquid level by adjusting, a pressure sensor 121 that detects the air pressure with respect to the pressure adjustment chamber 115, a drive unit 120 that moves the piston 113 in the syringe 112, and the air pressure of the pressure sensor 121 Based on the detection result, a time change rate of the air pressure with respect to the pressure adjustment chamber 115 in the pressing is derived, and when the derived time change rate is smaller than a predetermined threshold value, the piston 113 is controlled by controlling the driving unit 120. And a control unit 122 that moves so as to approach the surface.
[Selection] Figure 4

Description

  The present invention relates to a liquid supply apparatus, a liquid discharge apparatus, and a liquid supply method that supply liquid to a liquid discharge head that discharges liquid in a droplet shape by pressing the liquid.

  2. Related Art Inkjet technology is known in which ink is ejected in droplets onto recording paper or the like. This ink jet technology is applied to, for example, pattern formation and thin film formation in various device manufacturing processes. In recent years, such ink-jet technology has been applied to, for example, a semiconductor device manufacturing process and a light-emitting diode manufacturing process. In the manufacturing process of a semiconductor device, it is necessary to discharge a thermosetting resin having a high viscosity. Further, in the manufacturing process of the light emitting diode, it is necessary to discharge a liquid in which a solid phosphor is dispersed.

  In the ink jet technology, a liquid discharge head that discharges liquid is used. An example of a liquid discharge head is disclosed in Patent Document 1. The liquid discharge head described in Patent Literature 1 stores a liquid to be discharged in a storage chamber in which a supply hole for supplying a liquid and a discharge hole for discharging a liquid are provided in communication with each other. By reducing the volume in a short time, the liquid is discharged from the discharge hole. According to the liquid discharge head having such a structure, there is no portion where the rigid bodies rub against each other, and the solid contained in the liquid does not enter between the rigid bodies and damage the rigid body. Can do. Moreover, since the force which shrinks the volume of a storage chamber is strong, it is possible to discharge even a highly viscous liquid.

JP 2008-307466 A

  By the way, in the liquid discharge head of Patent Document 1, it is necessary to supply liquid into the storage chamber with a constant supply amount. However, since the volume of the storage chamber is small, the supply amount of liquid is small. Therefore, in the liquid supply apparatus that supplies liquid to the liquid discharge head disclosed in Patent Document 1, it is required to stably supply a constant amount of liquid with a minute supply amount. However, in a structure in which a liquid is supplied from a syringe by providing a blanker in a syringe in which the liquid is stored and pressing the liquid by moving the blanker by mechanical means, as commonly used, It is difficult to precisely control the amount of movement of the blanker. Therefore, it is difficult for a general liquid supply apparatus to supply a constant amount of liquid with a minute supply amount.

  Here, in JP-A-4-247261, a blanker that presses a liquid is provided in a syringe in which the liquid is stored, and the liquid is discharged from the syringe by pressurizing and moving the blanker with air pressure. A liquid ejection device is disclosed. In this liquid ejecting apparatus, a piston that moves following the movement of the blanker is provided in the syringe so that the air pressure of the blanker is constant. According to the liquid ejecting apparatus having such a structure, since a liquid is pressed by air pressure, a minute amount of liquid can be ejected. Further, since the air pressure of the blanker is made constant, the discharge amount of the liquid can be made constant. Therefore, it is conceivable that a certain amount of liquid is supplied to the liquid discharge head with a minute supply amount by applying this liquid discharge device to the liquid supply device. However, the liquid ejecting apparatus disclosed in Japanese Patent Laid-Open No. 4-247261 does not disclose a specific configuration for moving the piston so as to follow the movement of the blanker. For example, when a mechanism such as providing a position sensor on the blanker is employed, the configuration of the liquid supply apparatus becomes complicated.

  SUMMARY An advantage of some aspects of the invention is to provide a liquid supply apparatus, a liquid discharge apparatus, and a liquid supply method capable of supplying a constant amount of liquid with a minute supply amount. That is.

  In order to achieve the above object, a liquid supply apparatus according to an aspect of the present invention is a liquid supply apparatus that presses and supplies a liquid, the syringe storing the liquid, and the liquid in the syringe. A piston arranged to be separated from the liquid level in a first space where air is supplied and exhausted, and connected to the first space via the piston to supply air to the first space And supply / discharge means for pressing the liquid surface by adjusting the air pressure to the first space by discharging air from the first space and adjusting the air pressure to the first space by the supply and discharge, and the pressure to detect the air pressure to the first space Air pressure with respect to the first space in the pressing based on the detection result of the air pressure by the detection means, the drive means for moving the piston in the syringe, and the pressure detection means Control means for deriving a time change rate and moving the piston so as to approach the liquid surface of the liquid by controlling the driving means when the derived time change rate is smaller than a predetermined threshold value. It is characterized by.

  According to this aspect, since the liquid surface of the liquid is pressed by the air pressure with respect to the first space facing the liquid surface, a minute amount of liquid can be supplied. At this time, as the liquid supply proceeds, the amount of liquid stored in the syringe decreases, the distance between the piston and the liquid surface of the liquid increases, and the volume of the first space increases. Accordingly, when the air supply / discharge speed by the supply / discharge means is constant, the time change rate of the air pressure with respect to the first space decreases as the liquid supply proceeds, and the liquid supply amount by the liquid supply device decreases. However, according to this aspect, the air pressure with respect to the first space is detected, and the piston approaches the liquid level as the time change rate of the air pressure with respect to the first space decreases. The volume does not change greatly. Therefore, the supply amount of the liquid can be made constant. As a result, it is possible to realize a liquid supply apparatus that can supply a constant amount of liquid with a minute supply amount.

Here, a second space communicating with the supply / discharge means is formed inside the piston,
A plurality of through holes that connect the second space and the first space may be formed in a portion of the piston on the first space side facing the liquid surface of the liquid.

  According to this aspect, the air supplied by the supply / discharge means is once supplied to the second space of the piston, and then supplied to the first space facing the liquid level through the plurality of through holes. Therefore, it is possible to suppress a large amount of air from being supplied to the first space at a time. Therefore, even if the volume of the first space is reduced and the distance between the liquid surface of the liquid and the piston is narrowed in order to enhance the response of the liquid pressing to the air supply / discharge by the supply / discharge means, The supply of air by the means prevents the liquid surface of the liquid from rippled and the air from being caught in the liquid. In addition, it is possible to prevent the amount of change in the air pressure from becoming too large and the liquid supply amount from being easily varied.

  The openings of the plurality of through holes may be arranged along at least the outer periphery of the surface of the piston facing the liquid surface of the liquid.

  According to this aspect, since the liquid level of the liquid pressed by the air supplied by the supply / discharge means is more difficult to ripple, it is further suppressed that the air is caught in the liquid.

  In addition, the pressure detection unit detects an air pressure with respect to the first space in a first period in which air is supplied to the first space by the supply / discharge unit, and the control unit detects the air pressure in the first period. A time increase rate of the air pressure with respect to the first space in the pressing is derived based on a detection result of the air pressure with respect to the first space, and when the derived time increase rate is smaller than a predetermined threshold, the control of the driving unit is performed. You may go.

  According to this aspect, since the piston is moved based on the time rate of increase in the air pressure with respect to the first space, it is not necessary to always measure the time change rate of the air pressure with respect to the first space, and the load on the liquid supply device is reduced. Can do.

  In addition, the pressure detection unit detects an air pressure with respect to the first space in a second period in which air is discharged from the first space by the supply / discharge unit, and the control unit detects the air pressure in the second period. Based on the detection result of the air pressure for one space, a time decrease rate of the air pressure for the first space in the pressing is derived, and when the derived time decrease rate is smaller than a predetermined threshold, the driving means is controlled. Also good.

  According to this aspect, since the piston is moved based on the time decrease rate of the air pressure with respect to the first space, it is not necessary to always measure the time change rate of the air pressure with respect to the first space, and the load of the liquid supply device is reduced. Can do.

  The first space may be in contact with the piston and the liquid surface.

  According to this aspect, the distance between the liquid surface of the liquid and the piston can be reduced and the volume of the first space facing the liquid surface pressed by the air can be reduced. The responsiveness of pressing the liquid to the can be enhanced.

  A liquid discharge apparatus according to one aspect of the present invention includes a liquid discharge head that presses a liquid and discharges the liquid into droplets, and a liquid discharge apparatus that presses the liquid and supplies the liquid to the liquid discharge head. An apparatus, wherein the liquid ejection head includes a first member that presses the liquid, and a second member that is disposed to face the first member and forms a storage chamber in which the liquid is stored together with the first member. The storage chamber is disposed between the first member and the second member to define an outer peripheral portion of the storage chamber and is elastically deformed by being pressed toward the second member by the first member. An elastic member that increases or decreases the volume of the first member, and an operation member that elastically deforms the elastic member by relatively displacing the first member in a pressing direction approaching and separating from the second member, The liquid supply device includes the liquid In the syringe, a piston disposed so as to be separated from the liquid level in the first space in which air is supplied and exhausted, and the first space via the piston To supply air to the first space, discharge air from the first space, and adjust the air pressure to the first space by the supply and discharge to press the liquid level of the liquid The first means in the pressing based on the detection result of the air pressure by the discharge means, the pressure detecting means for detecting the air pressure with respect to the first space, the driving means for moving the piston in the syringe, and the pressure detecting means. Deriving the time change rate of the air pressure with respect to the space, and controlling the drive means when the derived time change rate is smaller than a predetermined threshold value, the piston And a controlling means for moving closer to the liquid surface of the liquid.

  According to this aspect, it is possible to realize a liquid ejection apparatus that can supply a predetermined amount of liquid to the liquid ejection head with a minute supply amount.

  The liquid supply method according to an aspect of the present invention is a liquid supply method using a liquid supply device that presses and supplies liquid, the liquid supply device including: a syringe that stores the liquid; A piston disposed so as to be separated from the liquid surface by a first space in which air is supplied and exhausted, and the liquid supply method supplies air to the first space and A pressing step of pressing the liquid level by discharging air from the first space and adjusting the air pressure to the first space by the supply and discharge, and the time change of the air pressure with respect to the first space in the pressing A moving step of deriving a rate and moving the piston so as to approach the liquid level of the liquid in the syringe when the derived time change rate is smaller than a predetermined threshold; Characterized in that it contains.

  According to this aspect, it is possible to realize a liquid supply method capable of supplying a constant amount of liquid with a minute supply amount.

  According to the present invention, it is possible to realize a liquid supply device, a liquid discharge device, and a liquid supply method that can supply a constant amount of liquid with a minute supply amount.

FIG. 1 is a perspective view showing a configuration of a liquid ejection apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing the appearance of the liquid discharge head according to the embodiment of the present invention. FIG. 3 is a perspective view showing the liquid ejection head according to the embodiment of the present invention in an exploded state. FIG. 4 is a cross-sectional view showing the configuration of the liquid discharge head and the liquid supply apparatus according to the embodiment of the present invention. FIG. 5A is a plan view in the pressing direction of the piston of the liquid supply apparatus according to the embodiment of the present invention. FIG. 5B is a plan view in the pressing direction of the piston of the liquid supply apparatus according to the embodiment of the present invention. FIG. 6 is a flowchart showing a liquid supply method and a liquid discharge method by the liquid discharge head in the liquid supply apparatus according to the embodiment of the present invention. FIG. 7 is a diagram showing a time change of air pressure with respect to the first space of the liquid supply apparatus according to the embodiment of the present invention. FIG. 8 is a diagram showing a change over time of the air pressure with respect to the first space of the liquid supply apparatus according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. The numerical values, shapes, materials, constituent elements, arrangement positions and connecting forms of the constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. The invention is limited only by the claims. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are not necessarily required to achieve the object of the present invention. It will be described as constituting a preferred form. In the drawings, elements that represent substantially the same configuration, operation, and effect are denoted by the same reference numerals.

  FIG. 1 is a perspective view showing a configuration of a liquid ejection apparatus 10 according to an embodiment of the present invention.

  The liquid ejection apparatus 10 includes an apparatus base 101, a head 102 supported so as to be reciprocally movable in the main scanning direction (X-axis direction in FIG. 1) with respect to the apparatus base 101, and the apparatus base 101. And a stage 103 supported so as to be reciprocally movable in the sub-scanning direction (Y-axis direction in FIG. 1).

  A head moving mechanism 104 is supported on the apparatus base 101. The head moving mechanism 104 includes a carriage shaft 105 that extends in the main scanning direction and a carriage 106 that is guided by the carriage shaft 105 so as to reciprocate. A head 102 is supported on the carriage 106. For example, when the carriage 106 reciprocates on the carriage shaft 105 by a drive source (not shown) such as a motor, the head 102 is reciprocated in the main scanning direction with respect to the apparatus base 101. The head 102 is provided with one or a plurality of liquid discharge heads that discharge liquid droplets by pressing a liquid such as silicon resin, and a liquid supply device that supplies the liquid thereto.

  A stage moving mechanism 107 is supported on the apparatus base 101. The stage moving mechanism 107 includes a pair of stage shafts 108a and 108b that extend in the sub-scanning direction and are spaced from each other. The stage 103 is guided by the pair of stage shafts 108a and 108b so as to be reciprocally movable. On the upper surface of the stage 103, an object to be ejected 109 such as recording paper is supported. For example, the stage 103 is reciprocated in the sub-scanning direction with respect to the apparatus base 101 by reciprocating the stage 103 on the pair of stage shafts 108a and 108b by a driving source (not shown) such as a motor.

  In the liquid discharge apparatus 10, the liquid from the head 102 to the discharge target 109 is formed into droplets while the head 102 and the discharge target 109 on the stage 103 are moved relative to the apparatus base 101. Discharge. As a result, the liquid adheres to the object to be ejected 109 in the form of dots, and a desired pattern or thin film can be formed on the object to be ejected 109, for example.

  Next, the configuration of the liquid ejection head 20 and the liquid supply apparatus 30 according to the present embodiment will be described with reference to FIGS.

  FIG. 2 is a perspective view showing an appearance of the liquid ejection head 20 according to the present embodiment. FIG. 3 is a perspective view showing the liquid ejection head 20 in an exploded state. FIG. 4 is a cross-sectional view showing the configuration of the liquid discharge head 20 and the liquid supply device 30. 5A and 5B are plan views (bottom views) of the piston 113 of the liquid supply device 30. FIG.

  The liquid discharge head 20 is a head that presses the liquid and discharges it in the form of droplets. The liquid discharge head 20 is disposed opposite the first member 205 that presses the liquid and the first member 205, and stores the liquid together with the first member 205. The second member 206 forming the storage chamber 213 and the first member 205 and the second member 206 are arranged between the first member 205 and the second member 206 to define the outer peripheral portion of the storage chamber 213. The elastic member 207 that increases and decreases the volume of the storage chamber 213 by being pressed and elastically deformed, and the first member 205 is relatively displaced in the pressing direction approaching and separating from the second member 206, And an actuating member 218 that elastically deforms the elastic member 207.

  Hereinafter, the liquid discharge head 20 will be described in detail.

  The liquid discharge head 20 includes a head body 201. The head main body 201 includes a holding body 202 and a heat storage body 203 that are fastened to each other.

  The heat storage body 203 is configured in a box shape having an upper surface opened. An opening 203a for exposing the discharge hole 214 of the second member 206 to the outside is provided at the bottom of the heat storage body 203. The heat storage body 203 is made of a material having high thermal conductivity, such as copper or stainless steel. A heating member 204 for heating the heat storage body 203 is attached to the inner surface of the heat storage body 203. The heating member 204 is composed of, for example, an electric heater and a ceramic heater. By transferring the heat from the heating member 204 to the heat storage body 203, the heat storage body 203 is maintained at a predetermined temperature (for example, 30 to 80 ° C.).

  The holding body 202 is attached to the upper surface of the heat storage body 203 so as to cover the opening on the upper surface of the heat storage body 203. The holding body 202 is provided with an opening 202a into which the first member 205 is inserted. The holding body 202 is made of a material having rigidity, such as stainless steel.

  Inside the head body 201, a first member 205, a second member 206, an elastic member 207, a biasing member 216, an electrode 217, and an operating member 218 are provided.

  The first member 205 is configured in a pipe shape, for example, and a supply channel 209 through which liquid is supplied from the outside of the head main body 201 is provided inside the upper end portion of the first member 205. A lower end portion of the first member 205 located on the second member 206 side defines a top surface side of the storage chamber 213 and has a supply hole 210 for supplying liquid to the storage chamber 213. The upper end portion of the first member 205 located on the side farther from the lower end portion on the second member 206 side extends to the outside of the head main body 201 through the opening of the holding body 202. The first member 205 is formed with an orifice-shaped supply hole 210 communicating with the downstream end of the supply flow path 209. The diameter of the supply hole 210 that supplies the liquid to one end side of the storage chamber 213 orthogonal to the pressing direction is configured to be smaller than the diameter of the supply flow path 209. The central axis of the supply channel 209 is disposed between the central axis of the supply hole 210 and the central axis of the discharge hole 214 that discharges liquid from the other end side of the storage chamber 213 orthogonal to the pressing direction. The central axis of the supply channel 209 and the central axis of the supply hole 210 are shifted from each other in a direction orthogonal to the pressing direction and extend substantially parallel to the pressing direction of the first member 205. A supply-side recess that connects the supply hole 210 and the storage chamber 213 to each other is formed at the lower end of the first member 205. The supply-side recess has a tapered shape whose cross-sectional area gradually increases toward the storage chamber 213. The inclination angle of the supply-side recess of the first member 205 with respect to the central axis of the supply hole 210 is, for example, about 45 degrees.

  The first member 205 is made of a material having high rigidity, for example, stainless steel, with respect to the elastic member 207 made of a member having elasticity and chemical resistance such as silicon rubber and fluorine rubber. As dimensions relating to the first member 205, for example, the outer diameter of the first member 205 is about 5 mm, the diameter of the orifice-shaped supply hole 210 is about 0.15 mm, the length of the supply hole 210 is about 1 mm, The supply channel 209 for supplying the liquid has a diameter of about 1.5 mm, and the maximum value of the diameter of the supply-side recess that connects the supply hole 210 and the storage chamber 213 to each other is about 0.5 mm.

  The second member 206 is attached to the bottom of the heat storage body 203 so as to face the lower end surface of the first member 205. On the upper surface of the second member 206, for example, a circular recess for forming a storage chamber is formed. The storage chamber 213 in which the liquid is stored is formed by the cooperation of the lower end surface of the first member 205 and the storage chamber forming recess of the second member 206. The lower end surface (including the supply-side recess) of the first member 205 defines the upper surface of the storage chamber 213, and the storage chamber forming recess (including the discharge-side recess) of the second member 206 is the lower surface of the storage chamber 213. Stipulate. Inside the second member 206, a discharge hole 214 communicating with the storage chamber 213 is formed. The discharge hole 214 is exposed to the outside through the opening 203 a of the heat storage body 203. A discharge-side recess that connects the discharge hole 214 and the storage chamber 213 to each other is formed at the upper end of the second member 206. The discharge-side recess has a tapered shape in which the cross-sectional area gradually increases toward the storage chamber 213. The inclination angle of the discharge side recess with respect to the central axis of the discharge hole 214 is, for example, about 45 degrees.

  The second member 206 is made of a material having high thermal conductivity, such as stainless steel and ceramic material. The second member 206 is thermally connected to the heat storage body 203. Thereby, the heat of the heat storage body 203 heated by the heating member 204 is transmitted to the liquid filled in the discharge hole 214 via the second member 206. Here, “thermally connected” means that the heat storage body 203 and the second member 206 are in direct or indirect contact with each other and the heat of the heat storage body 203 can be sufficiently transferred to the second member 206. The state that has been done. Further, “indirect contact” refers to a state in which, for example, a member having high thermal conductivity is disposed between the heat storage body 203 and the second member 206.

  As dimensions relating to the second member 206, for example, the diameter of the discharge hole 214 is about 0.15 mm, the length of the discharge hole 214 is 0.03 to 0.5 mm, and the discharge that connects the discharge hole 214 and the storage chamber 213 to each other. The maximum value of the diameter of the side recess is configured to be about 1 mm.

  Further, the diameter of the storage chamber 213 is configured to be larger than the maximum value of the diameter of the supply side recess of the first member 205 and the maximum value of the diameter of the discharge side recess of the second member 206.

  The elastic member 207 is formed in a thin plate shape and a ring shape in an XY plan view in the pressing direction. The elastic member 207 is disposed between the first member 205 and the second member 206. The elastic member 207 defines the outer peripheral portion of the storage chamber 213 in a direction orthogonal to the pressing direction by being disposed on the outer peripheral portion of the storage chamber forming recess. The cross-sectional shape of the storage chamber 213 in a plane including a direction orthogonal to the pressing direction is a circular shape. As will be described later, when the elastic member 207 is pressed toward the second member 206 side by the first member 205 and elastically deformed, the elastic deformation of the elastic member 207 radially outward is the outer periphery of the recess for forming the storage chamber. Regulated by the department. The elastic member 207 also has a sealing function for preventing the liquid in the storage chamber 213 from leaking to the outside. As the dimensions of the elastic member 207, for example, the thickness t is 0.05 mm to 0.5 mm, the outer diameter is 5.2 to 7 mm, and the inner diameter is 0.2 to 4.8 mm.

  The supply hole 210 communicates with one end side of the storage chamber 213 in the direction orthogonal to the pressing direction, and the discharge hole 214 communicates with the other end side of the storage chamber 213 in the direction orthogonal to the pressing direction. . The supply hole 210 is disposed at a position shifted from the discharge hole 214 in a direction orthogonal to the pressing direction. The arrangement interval in the direction orthogonal to the pressing direction of the supply hole 210 and the discharge hole 214 is configured to be 1.0 to 3.6 mm, for example.

  The actuating member 218 is an actuator composed of, for example, a laminated piezoelectric element. A through hole is provided in the central portion of the operating member 218, and the first member 205 is inserted into the through hole. Thus, the operating member 218 is disposed inside the head body 201 so as to surround the first member 205. The upper end 218a of the operating member 218 is firmly fixed to the outer peripheral surface of the first member 205 with an adhesive or the like. The lower end portion of the operating member 218 is in contact with the upper surface of the second member 206 via a part of the elastic member 207. An urging member 216 composed of a disc spring or the like is disposed between the upper end 218 a of the operating member 218 and the lower surface of the holding body 202, and the lower end of the operating member 218 is urged by the urging force of the urging member 216. The portion is pressed against the upper surface of the second member 206. The force with which the biasing member 216 presses the support portion 205a is, for example, about 20 kgf.

  An electrode 217 is disposed on the outer periphery of the operating member 218. When a voltage is applied to the electrode 217, the operating member 218 as a whole is held in an extended state that extends in the Z-axis direction. At this time, the first member 205 is displaced in a direction away from the second member 206 in the pressing direction by the extension force of the operating member 218. When the application of the voltage to the electrode 217 is released, the operating member 218 is maintained in a contracted state in which the operating member 218 contracts in the Z-axis direction as a whole. At this time, the first member 205 is displaced in a direction relatively close to the second member 206 in the pressing direction by the contraction of the operating member 218 and the urging force of the urging member 216. The displacement amount in the pressing direction of the first member 205 when the operating member 218 expands or contracts is, for example, about 10 μm.

  As described above, in the liquid discharge head 20, the supply hole 210 of the first member 205 is communicated with one end side of the storage chamber 213 in the direction orthogonal to the pressing direction, and the discharge hole 214 of the second member 206 is orthogonal to the pressing direction. The storage chamber 213 communicates with the other end of the storage chamber 213 in the direction in which it moves. The central axis of the supply hole 210 is disposed at a position shifted from the central axis of the discharge hole 214. With such a configuration, the liquid supplied from the supply hole 210 to the storage chamber 213 flows from one end side to the other end side of the storage chamber 213 in a direction orthogonal to the pressing direction. Thereby, since the liquid flows while pushing the air in the storage chamber 213 to the discharge hole 214, the occurrence of air accumulation in the storage chamber 213 is suppressed, and the liquid filling property in the storage chamber 213 is efficiently improved. Can be increased.

  As shown in FIG. 4, the liquid ejecting apparatus 10 according to the present embodiment further presses a liquid having a pressure equal to or higher than the atmospheric pressure to supply the liquid to the supply channel 209 of the liquid ejecting head 20. And an operation control unit 111 that controls the operation of the operation member 218 of the liquid ejection head 20.

  The operation control unit 111 controls the voltage applied to the electrode 217 of the operation member 218. When discharging the liquid from the liquid discharge head 20, the operation control unit 111 applies a voltage to the electrode 217 of the operation member 218. When liquid is not ejected from the liquid ejection head 20, the operation control unit 111 releases the voltage applied to the electrode 217. Accordingly, the operation control unit 111 repeats the application and release of the voltage to the electrode 217 in a predetermined cycle, whereby the liquid discharge from the liquid discharge head 20 is performed in the predetermined cycle.

  The liquid supply device 30 is a device that presses the liquid and supplies the liquid to the liquid ejection head 20. Air is supplied to and exhausted from the syringe 112 that stores the liquid and the liquid level of the liquid in the syringe 112. A piston 113 disposed so as to be separated by a pressure adjustment chamber 115 as a first space, and is connected to the pressure adjustment chamber 115 via the piston 113 to supply air to the pressure adjustment chamber 115 and the pressure adjustment chamber 115. Air source 117, an air pipe 119 and a leak valve (not shown) as pressure supply / discharge means for pressing the liquid level by adjusting the air pressure with respect to the pressure adjusting chamber 115 by supplying and discharging, and pressure A pressure sensor 121 as pressure detecting means for detecting the air pressure with respect to the adjustment chamber 115 and the piston 113 are moved in the syringe 112. When the time change rate of the air pressure with respect to the pressure adjustment chamber 115 in the pressing is derived based on the detection result of the air pressure by the drive unit 120 and the pressure sensor 121 as the moving means, and the derived time change rate is smaller than a predetermined threshold value And a control unit 122 as control means for moving the piston 113 so as to approach the liquid level by controlling the drive unit 120.

  Here, a volume adjustment chamber 113a as a second space communicating with the air pipe 119 is formed inside the piston 113, and a volume facing the liquid surface of the piston 113 on the pressure adjustment chamber 115 side has a volume. A plurality of through-holes 113b communicating with the adjustment chamber 113a and the pressure adjustment chamber 115 are formed.

  Further, the openings of the plurality of through holes 113b are arranged at least along the outer periphery of the surface of the piston 113 that faces the liquid surface of the liquid.

  The pressure sensor 121 detects the air pressure with respect to the pressure adjustment chamber 115 in the first period in which air is supplied to the pressure adjustment chamber 115 by the supply / discharge means, and the control unit 122 detects the pressure adjustment chamber in the first period. The time increase rate of the air pressure for the pressure adjusting chamber 115 in the pressing is derived based on the air pressure detection result for the pressure 115, and the drive unit 120 may be controlled when the derived time increase rate is smaller than a predetermined threshold. .

  In addition, the pressure sensor 121 detects the air pressure with respect to the pressure adjustment chamber 115 in the second period in which air is discharged from the pressure adjustment chamber 115 by the supply / discharge means, and the control unit 122 detects the air pressure with respect to the pressure adjustment chamber 115 in the second period. Based on the detection result of the air pressure, the time reduction rate of the air pressure with respect to the pressure adjustment chamber 115 in the pressing may be derived, and the control of the drive unit 120 may be performed when the derived time reduction rate is smaller than a predetermined threshold.

  The pressure adjustment chamber 115 is in contact with the piston 113 and the liquid level.

  Hereinafter, the liquid supply device 30 will be described in detail.

  The liquid supply device 30 includes a syringe 112, a piston 113, a liquid supply source 116, an air source 117, an O-ring 118, an air pipe 119, a leak valve (not shown), a driving unit 120, and a pressure sensor. 121 and a control unit 122.

  The syringe 112 is a cylindrical container in which liquid supplied to the liquid discharge head 20 is stored. At the lower end of the syringe 112, a discharge hole through which the liquid in the syringe 112 is discharged is provided. This discharge hole is connected to the supply flow path 209 of the first member 205 of the liquid discharge head 20 via a connection tube.

  The piston 113 is a columnar rigid body and is slidably provided inside the syringe 112. Of the space inside the syringe 112 defined by the piston 113, a lower space communicating with the discharge hole of the syringe 112 is provided with a liquid chamber 114 filled with liquid, and a pressure adjusting chamber 115 sealed with compressed air. Is provided. The liquid chamber 114 is filled with a liquid in advance, and the discharge hole of the syringe 112 is communicated. The pressure adjustment chamber 115 in which air is supplied to and exhausted from the liquid surface of the liquid chamber 114 is formed between the lower surface of the piston 113 and the liquid chamber 114. The pressure adjustment chamber 115 is supplied from the air source 117. Filled with compressed air. The liquid chamber 114 communicates with the supply flow path 209 of the first member 205 via a connection tube, and the liquid surface of the liquid chamber 114 is pressed by the compressed air in the pressure adjustment chamber 115 and discharged from the discharge hole of the syringe 112. The liquid thus supplied is supplied to the supply channel 209.

  In FIG. 4, the syringe 112 is disposed at a position higher than the liquid ejection head 20, but may be disposed at a position lower than the liquid ejection head 20. Accordingly, in order to facilitate the pressurized supply of the liquid from the liquid supply apparatus 30 to the liquid discharge head 20 at an atmospheric pressure or higher, and to prevent the liquid from being discharged from the discharge holes 214 through which the liquid is discharged from the liquid discharge head 20. In addition, it is possible to eliminate the need to apply a negative pressure from a negative pressure source (not shown) to the pressure adjustment chamber 115.

  Inside the piston 113, a volume adjustment chamber 113a is formed. A plurality of through-holes 113b for communicating the volume adjustment chamber 113a and the volume adjustment chamber 113a are formed in a portion (lower part) on the liquid chamber 114 side in contact with the pressure adjustment chamber 115 of the piston 113. On the other hand, a supply hole for communicating the air pipe 119 and the volume adjustment chamber 113a is formed in a portion (upper part) opposite to the liquid chamber 114 of the piston 113.

  A concave portion continuous in the circumferential direction is formed in the outer peripheral portion of the piston 113 in contact with the inner surface of the syringe 112, and an O-ring 118 is provided in the concave portion. The O-ring 118 is made of an elastic body and fills the gap between the outer peripheral portion of the piston 113 and the inner surface of the syringe 112. The compressed air for the pressure adjusting chamber 115 is formed from the gap between the outer peripheral portion of the piston 113 and the inner surface of the syringe 112. Suppresses leakage.

  The air source 117 is composed of an air compressor or a factory positive pressure air source, and supplies a constant pressure of compressed air to the air pipe 119, the piston 113 and the pressure adjustment chamber 115 until the air pressure with respect to the pressure adjustment chamber 115 reaches a predetermined constant pressure. The air pressure for the pressure adjusting chamber 115 is supplied to a predetermined constant pressure. Then, when the air pressure with respect to the pressure regulation chamber 115 again decreases from a predetermined constant pressure, the supply of compressed air is resumed. Thereby, the air pressure with respect to the pressure regulation chamber 115 is maintained at a constant pressure.

  The air pipe 119 is a compressed air flow path that guides the compressed air supplied from the air source 117 to the volume adjustment chamber 113 a of the piston 113. The air pipe 119 is disposed in an upper space opposite to the lower space of the syringe 112 in the inner space of the syringe 112 partitioned by the piston 113. The compressed air guided by the air pipe 119 first flows into the volume adjustment chamber 113a, and then flows into the pressure adjustment chamber 115 through the through hole 113b. The liquid in the liquid chamber 114 is pressurized by the pressure of the compressed air supplied to the pressure adjusting chamber 115, and the pressure of the liquid becomes a constant pressure larger than the atmospheric pressure. In this way, the liquid having a pressure equal to or higher than the atmospheric pressure is supplied to the supply channel 209 of the first member 205 through the connection tube.

  A pressure sensor 121 and a leak valve are connected to the air pipe 119. The pressure sensor 121 measures the air pressure in the pressure adjustment chamber 115 by measuring the air pressure in the air pipe 119. The leak valve adjusts the air pressure in the air pipe 119, that is, the air pressure with respect to the pressure adjustment chamber 115 by leaking compressed air in the air pipe 119, that is, in the pressure adjustment chamber 115 to the outside.

  As shown in FIG. 5A, the plurality of through holes 113b are arranged on the lower surface of the piston 113 along the circumferential direction of the piston 113 (volume adjusting chamber 113a). The plurality of through holes 113b may be arranged in a matrix on the lower surface of the piston 113 as shown in FIG. 5B.

  The drive unit 120 includes a pusher and a feed screw (such as a ball screw or a trapezoidal screw), and determines the position (height) of the piston 113 in the syringe 112 by sliding the piston 113 in the feed direction. The drive unit 120 is disposed in the upper space of the syringe 112. The drive unit 120 is directly or indirectly connected to the upper surface of the piston 113, and determines the position (height) of the piston 113 by moving the piston 113. When the drive unit 120 lowers the piston 113, the piston 113 approaches the liquid surface of the liquid chamber 114, and the volume of the pressure adjustment chamber 115 decreases. On the other hand, when the drive unit 120 raises the piston 113, the piston 113 moves away from the liquid surface of the liquid chamber 114, and the volume of the pressure adjustment chamber 115 increases.

  The control unit 122 controls the drive unit 120 based on the measurement result of the air pressure with respect to the pressure adjustment chamber 115 by the pressure sensor 121. Specifically, the control unit 122 reduces the amount of liquid in the liquid chamber 114 by the supply of liquid from the syringe 112 to the liquid ejection head 20 by pressing the compressed air against the liquid surface of the liquid chamber 114, and the pressure adjustment chamber. When the volume of 115 increases, the piston 113 is lowered by the drive unit 120 to reduce the volume of the pressure adjustment chamber 115. That is, the control unit 122 controls the drive unit 120 so that the volume of the pressure adjustment chamber 115 is substantially constant.

  Next, the liquid supply method by the liquid supply apparatus 30 of this Embodiment is demonstrated. FIG. 6 is a flowchart showing a liquid supply method in the liquid supply apparatus 30 and a liquid discharge method by the liquid discharge head 20.

  The liquid supply method by the liquid supply device 30 is such that air is supplied to the pressure adjustment chamber 115 and air is discharged from the pressure adjustment chamber 115, and the air pressure with respect to the pressure adjustment chamber 115 is adjusted by supply and discharge. Depressing the pressure step (step S5) and deriving the time change rate of the air pressure with respect to the pressure adjustment chamber 115 in the press, and when the derived time change rate is smaller than a predetermined threshold (the air pressure rising speed is slow), A moving step (steps S6 and S7) for moving the piston 113 so as to approach the liquid level in the syringe 112.

  Hereinafter, the liquid supply method by the liquid supply apparatus 30 will be described in detail.

  First, in the syringe 112 in which the liquid is stored, the position of the piston 113 is set at a desired interval by the pressure adjustment chamber 115 with respect to the liquid surface of the liquid chamber 114 before the liquid supply device 30 starts supplying the liquid. And the initial position of the piston 113 is set (step S1). Depending on the distance between the liquid level of the liquid chamber 114 and the piston 113 set at this time, that is, the volume of the pressure adjusting chamber 115 and the supply speed of compressed air by the air source 117, the liquid supply in one supply operation The amount of liquid supplied by the device 30 changes. Note that the one-time supply operation means that the air pressure in the storage chamber 213 rises from, for example, the atmospheric pressure to become a constant air pressure, and after the constant air pressure is maintained, the liquid in the liquid chamber 114 is returned to the atmospheric pressure again. The operation of pressing the liquid surface and supplying the liquid from the liquid supply device 30 is shown.

  Next, the liquid in the liquid chamber 114 is discharged from the liquid supply device 30, and the liquid supply device 30 supplies the liquid to the liquid discharge head 20 (step S2). The liquid supply by the liquid supply device 30 is performed by pressing the liquid surface of the liquid in the liquid chamber 114. And the pressing at this time supplies compressed air from the air source 117 to the pressure adjustment chamber 115 via the air pipe 119 and the volume adjustment chamber 113a and the through hole 113b of the piston 113, and the supply is stopped to stop this state. After maintaining for a certain period, the compressed air in the pressure adjusting chamber 115 is leaked (exhausted) through the leak valve. That is, the compressed air is supplied to the pressure adjusting chamber 115, the air pressure to the pressure adjusting chamber 115 is increased to a constant air pressure, and the air pressure is maintained at the constant air pressure for a certain period, and then the compressed air in the pressure adjusting chamber 115 is leaked. This is done by returning to atmospheric pressure again. Although the supply of compressed air from the air source 117 to the pressure adjustment chamber 115 is stopped on the air source 117 side and the compressed air is leaked by the leak valve, the compressed air from the air source 117 to the pressure adjustment chamber 115 is used. The supply stop and exhaust operation may be performed by a three-port valve or the like (not shown) which is a supply / discharge switching valve as one operation valve.

  Next, the time change rate of the air pressure with respect to the pressure adjustment chamber 115 in the liquid supply by the liquid supply device 30 in step S2 is derived, and the derived value is held (step S3). The time change rate is derived by the control unit 122 monitoring the air pressure measurement with respect to the pressure adjustment chamber 115 by the pressure sensor 121 during the period during which compressed air is supplied or discharged. The initial value (reference value) of the time change rate is held in the storage unit (memory). For example, when the air pressure supplied to the pressure adjustment chamber 115 is the maximum (set value), the constant value is 100%, the pressure value is 0%, and the air pressure with respect to the pressure adjustment chamber 115 is shown in FIG. Let us consider a case where the time change shown in FIG. In this case, for example, in a period during which compressed air is supplied, calculation is performed by dividing the pressure value difference of 80% at time t1 until the air pressure to the pressure adjustment chamber 115 changes from the pressure value of 10% to the pressure value of 90%. The first time increase rate is derived as a time change rate. Alternatively, in the period during which the compressed air is discharged, the pressure is calculated by dividing the pressure value difference of 80% at time t3 until the air pressure with respect to the pressure regulation chamber 115 changes from the pressure value of 90% to the pressure value of 10%. The 1 hour reduction rate is derived as the time change rate.

  Next, discharge of the liquid in the storage chamber 213 by the liquid discharge head 20 is started (step S4). The liquid discharge by the liquid discharge head 20 is realized by the following operation. First, when the operation control unit 111 releases the application of the voltage to the electrode 217 of the operation member 218, the operation member 218 receives the urging force of the urging member 216 and is displaced from the extended state to the contracted state. As a result, the first member 205 is pressed toward the second member 206 via the elastic member 207 by the contraction force of the actuating member 218, so the first member 205 is pressed against the second member 206. Are relatively displaced by a predetermined amount of displacement (for example, about 10 μm). In this state, the elastic member 207 is pressed and elastically deformed by the first member 205 toward the second member 206, and the first member 205 presses the liquid in the storage chamber 213. Thereby, since the volume of the storage chamber 213 is reduced, pressure is applied to the liquid in the storage chamber 213, and the liquid in the storage chamber 213 is discharged from the discharge hole 214 in the form of droplets. Next, when the discharge of the liquid is completed, the operation member 218 is displaced from the contracted state to the extended state by applying a voltage to the electrode 217 of the operation member 218 by the operation control unit 111. As a result, the first member 205 is displaced relative to the second member 206 in a direction away from the second member 206 against the urging force of the urging member 216, and the elastic member 207 is pressed by the first member 205. Is released. By restoring the elastic deformation of the elastic member 207, the volume of the storage chamber 213 increases. As a result, the pressure acting on the liquid in the storage chamber 213 decreases, and the liquid in the supply channel 209 is supplied to the storage chamber 213 through the supply hole 210 of the first member 205. In the liquid discharge by the liquid discharge head 20, the liquid discharge from the storage chamber 213 and the liquid supply operation to the storage chamber 213 are repeated. As a result, the liquid adheres to the object to be discharged 109 in the form of dots, and for example, a desired pattern or thin film can be formed on the object to be discharged 109.

  Next, after the liquid discharge by the liquid discharge head 20 is performed a predetermined number of times (for example, 10,000 times), the liquid in the liquid chamber 114 is discharged from the liquid supply device 30 to the liquid discharge head 20 from the liquid supply device 30. The liquid is supplied (step S5). The liquid supply by the liquid supply device 30 is performed by pressing the liquid surface of the liquid in the liquid chamber 114 as in step S2. Note that the liquid supply device 30 may supply the liquid to the liquid discharge head 20 every time the liquid discharge head 20 performs the discharge once.

  Next, the time change rate of the air pressure with respect to the pressure adjustment chamber 115 in the liquid supply by the liquid supply device 30 in step S5 is derived, and the derived time change rate is set to the initial value held in the storage unit in step S3. It is compared with a value (predetermined threshold) obtained by adding the values, and it is determined whether or not the derived time change rate is smaller than the predetermined threshold (step S6). The time change rate is derived by the control unit 122 monitoring the measurement of the air pressure with respect to the pressure regulation chamber 115 by the pressure sensor 121 during the period during which compressed air is supplied or discharged. For example, when the air pressure supplied to the pressure adjustment chamber 115 is the maximum (set value), the pressure value is 100%, and when the pressure is atmospheric pressure, the pressure value is 0%. Let us consider a case where the time change shown in FIG. In this case, for example, in the period during which compressed air is supplied, the difference is calculated by dividing the pressure value difference of 80% at time t2 until the air pressure to the pressure adjustment chamber 115 changes from the pressure value of 10% to the pressure value of 90%. The second time increase rate is derived as the time change rate. Alternatively, in the period during which the compressed air is discharged, the calculation is performed by dividing the pressure value difference of 80% at time t4 until the air pressure with respect to the pressure adjustment chamber 115 changes from the pressure value of 90% to the pressure value of 10%. The 2-hour decrease rate is derived as the time change rate. In the comparison, the second time increase rate is smaller than a value obtained by adding a predetermined value to the first time increase rate (initial value (reference value)), or the second time decrease rate is determined in consideration of the threshold value. This is performed by determining whether or not the first time decrease rate (initial value (reference value)) is smaller than a predetermined value.

  At this time, the integral value derived by time-integrating the air pressure with respect to the pressure adjustment chamber 115 is proportional to the amount of liquid supplied by the liquid supply device 30. Then, as the rate of change of the air pressure with respect to the pressure adjustment chamber 115 increases, the air pressure with respect to the pressure adjustment chamber 115 reaches the maximum value in a short time, and the integrated value increases. Therefore, the supply amount of the liquid is proportional to the time change rate of the air pressure with respect to the pressure adjustment chamber 115. Accordingly, the liquid supply is determined by determining whether the rate of time change is smaller than a predetermined threshold (whether the distance between the piston 113 and the liquid surface is large and the volume of the pressure adjustment chamber 115 is not too large). It can be determined whether or not the amount of liquid supplied by the device 30 is too small beyond the allowable range (the volume of the pressure adjustment chamber 115 is too large). The predetermined value added to the initial value (reference value) of the time change rate when deriving the threshold is the liquid supply from the liquid supply device 30 with respect to the change in the air pressure time change rate due to the viscosity of the liquid or the like. If the amount does not change significantly, it is set large, and conversely if it changes greatly, it is set small.

  Next, when it is determined that the time change rate of the air pressure with respect to the pressure adjustment chamber 115 is equal to or greater than a predetermined threshold (No in step S6), the liquid is discharged by the liquid discharge head 20 a predetermined number of times, and then the liquid supply is performed. The liquid is supplied by the device 30. At this time, the position of the piston 113 is not changed in the liquid supply device 30.

  On the other hand, when it is determined that the time change rate of the air pressure with respect to the pressure adjustment chamber 115 is smaller than the predetermined threshold (the volume of the pressure adjustment chamber 115 is large) (Yes in step S6), the piston 113 is set to the liquid level of the liquid chamber 114. It moves in the feed direction so as to approach (step S7). Thereafter, as in the case of No in step S6, the liquid supply by the liquid supply device 30 is performed after the liquid discharge by the liquid discharge head 20 is performed a predetermined number of times. The movement of the piston 113 is performed by the control unit 122 controlling the driving unit 120 to lower the piston 113 by a predetermined amount. Thus, the pressure adjustment chamber 115 becomes too large due to the supply of liquid from the liquid chamber 114 of the syringe 112, and the time change rate of the air pressure with respect to the pressure adjustment chamber 115 becomes too small. In comparison, since the volume of the pressure adjustment chamber 115 is reduced, the time change rate of the air pressure with respect to the pressure adjustment chamber 115 is increased.

  As described above, according to the liquid supply device 30 of the present embodiment, a minute amount of liquid is supplied from the syringe 112 because the liquid level of the liquid chamber 114 of the syringe 112 is pressed by the air pressure with respect to the pressure adjustment chamber 115. can do. At this time, as the liquid supply proceeds, the amount of liquid stored in the syringe 112 decreases, the distance between the piston 113 and the liquid surface of the liquid chamber 114 increases, and the volume of the pressure adjustment chamber 115 increases. Accordingly, when the supply / discharge speed of the compressed air is constant, the time change rate of the air pressure with respect to the pressure adjustment chamber 115 decreases (time increases) as the liquid supply proceeds, and the liquid within the predetermined discharge time by the liquid supply device 30 The amount of supply decreases. However, according to the liquid supply device 30 of the present embodiment, the piston 113 approaches the liquid surface of the liquid chamber 114 when the rate of time change of the air pressure with respect to the pressure adjustment chamber 115 becomes smaller than the allowable range. However, the volume of the pressure adjustment chamber 115 does not increase beyond the allowable range. Accordingly, it is possible to suppress the liquid supply amount from becoming smaller than the allowable range. As a result, it is possible to realize a liquid supply apparatus that can supply a constant amount of liquid with a minute supply amount.

  Further, according to the liquid supply device 30 of the present embodiment, the compressed air supplied from the air source 117 is temporarily supplied to the volume adjustment chamber 113a and then supplied to the pressure adjustment chamber 115 through the through hole 113b. Is done. Therefore, by setting the plurality of through holes 113b to be small, it is possible to suppress a large amount of compressed air from being concentrated and supplied to the pressure adjustment chamber 115 at a time. Therefore, in order to increase the responsiveness of the pressure of the liquid in the liquid chamber 114 with respect to the supply and discharge of the compressed air to the pressure adjustment chamber 115, the volume of the pressure adjustment chamber 115 is reduced, and the liquid level of the liquid chamber 114 and the piston 113 are reduced. Even when the distance between the two is narrowed, the supply of compressed air suppresses the liquid surface of the liquid chamber 114 from rippled and air being caught in the liquid. In addition, it is possible to prevent the amount of change in the air pressure from becoming too large and the liquid supply amount from being easily varied. The formation of the through hole 113b may be performed with a porous material.

  As described above, the liquid supply device, the liquid discharge device, and the liquid supply method of the present invention have been described based on the embodiment, but the present invention is not limited to this embodiment. The present invention includes various modifications made by those skilled in the art without departing from the scope of the present invention. Moreover, you may combine each component in a some modified example arbitrarily in the range which does not deviate from the meaning of invention.

  For example, in the above embodiment, the time change rate is derived by dividing the difference in air pressure (pressure value difference) in the pressure adjustment chamber 115 by the time, but supply of compressed air to the pressure adjustment chamber 115 is started. From time to time until a predetermined air pressure is reached, or the air pressure at a predetermined time may be derived as a time change rate.

  Further, in the above embodiment, the piston 113 is moved based on the time increase rate or the time decrease rate of the air pressure with respect to the pressure adjustment chamber 115. However, both the time increase rate and the time decrease rate of the air pressure with respect to the pressure adjustment chamber 115 are used. The piston 113 may be moved based on the above. In this case, the control unit 122 moves the piston 113 when at least one of the time increase rate and the time decrease rate of the air pressure with respect to the pressure adjustment chamber 115 becomes smaller than a predetermined threshold value. When the piston 113 is moved based only on either the time increase rate or the time decrease rate, there is an advantage that the load on the liquid supply device 30 can be reduced. On the other hand, when the piston 113 is moved based on both the time increase rate and the time decrease rate, there is an advantage that it is possible to respond sensitively to changes in the liquid supply amount.

  In the above embodiment, the movement amount of the piston 113 is a fixed value and is constant. However, the difference between the time change rate of the air pressure with respect to the pressure adjustment chamber 115 and a predetermined threshold value increases (the liquid chamber 114). The amount of movement of the piston 113 may be changed so that the amount of movement increases in accordance with the amount of liquid and the elapsed time of the liquid in the syringe 112 (viscosity change etc.). In this case, a correspondence table indicating a correspondence relationship between the difference amount and the movement amount of the piston 113 is stored in the storage unit. When the movement amount is a fixed value, there is an advantage that the configuration of the liquid supply device 30 can be simplified. However, when the movement amount is changed, it is possible to accurately cope with a change in the liquid supply amount. There is an advantage.

  In the above embodiment, the threshold value for the time change rate is derived based on the time change rate of the air pressure with respect to the pressure adjustment chamber 115 in the initial supply of the liquid, but a preset time change rate may be used. In this case, since the step of deriving the threshold value of the time change rate can be eliminated, there is an advantage that the load on the liquid supply device 30 can be reduced. When the time change rate is set in advance, the time change rate set for each liquid lot may be changed. Also, the supply operation is performed in advance until all the liquid in the piston 113 is supplied, and the time change rate set based on the relationship between the change in the air pressure with respect to the pressure adjustment chamber 115 obtained at that time and the supply amount. May be derived.

  In the above-described embodiment, the comparison between the time change rate of the air pressure with respect to the pressure adjustment chamber 115 and the threshold value is performed every time the liquid is supplied by the liquid supply device 30, but a predetermined number of times (for example, 10 times of supply) may be performed or only at a desired timing. In this case, there is an advantage that the load of the liquid supply device 30 can be reduced.

  Moreover, in the said embodiment, although the biasing member was comprised with the disc spring, the press member can also be comprised with the leaf | plate spring etc. which have strong elasticity, for example.

  The present invention can be applied as a liquid supply apparatus, a liquid discharge apparatus, and a liquid supply method for forming various patterns and thin films in the manufacturing process of various devices. Further, the present invention provides a film for emitting white light from a blue light emitting diode by, for example, discharging a liquid in which a solid phosphor is dispersed to a light emitting portion of the light emitting diode in a manufacturing process of the light emitting diode. The present invention can also be applied as a liquid supply device, a liquid discharge device, and a liquid supply method.

DESCRIPTION OF SYMBOLS 10 Liquid discharge apparatus 20 Liquid discharge head 101 Apparatus base 102 Head 103 Stage 104 Head moving mechanism 105 Carriage shaft 106 Carriage 107 Stage moving mechanism 108a, 108b Stage shaft 109 To-be-discharged object 30 Liquid supply apparatus 111 Operation control part 112 Syringe 113 Piston 113a Volume adjustment chamber (second space)
113b Through hole 114 Liquid chamber 115 Pressure adjusting chamber (first space)
116 Liquid supply source 117 Air source 118 O-ring 119 Air pipe 120 Drive unit 121 Pressure sensor 122 Control unit 201 Head body 202 Holding body 202a, 203a Opening 203 Heat storage body 204 Heating member 205 First member 206 Second member 207 Elastic member 209 Supply channel 210 Supply hole 213 Storage chamber 214 Discharge hole 216 Biasing member 217 Electrode 218 Actuating member

Claims (8)

A liquid supply device that presses and supplies liquid,
A syringe for storing the liquid;
In the syringe, a piston disposed so as to be separated from the liquid level in the first space in which air is supplied and exhausted;
By being connected to the first space via the piston and supplying air to the first space and discharging air from the first space, and adjusting the air pressure with respect to the first space by the supply and discharge Supply / discharge means for pressing the liquid level of the liquid;
Pressure detecting means for detecting air pressure with respect to the first space;
Driving means for moving the piston in the syringe;
A time change rate of air pressure with respect to the first space in the pressing is derived based on a detection result of the air pressure by the pressure detection unit, and the drive unit is controlled when the derived time change rate is smaller than a predetermined threshold value. And a control means for moving the piston so as to approach the liquid surface of the liquid. A second space communicating with the supply / discharge means is formed inside the piston,
2. The liquid supply according to claim 1, wherein a plurality of through-holes communicating the second space and the first space are formed in a portion of the piston on the first space side facing the liquid surface of the liquid. apparatus. The liquid supply device according to claim 2, wherein the openings of the plurality of through holes are arranged along at least an outer periphery of a surface of the piston facing the liquid surface of the liquid. The pressure detecting means detects air pressure with respect to the first space in a first period in which air is supplied to the first space by the supply / discharge means;
The control means derives a time increase rate of the air pressure with respect to the first space in the pressing based on a detection result of the air pressure with respect to the first space in the first period, and the derived time increase rate is less than a predetermined threshold value. The liquid supply apparatus according to any one of claims 1 to 3, wherein the driving unit is controlled when it is small. The pressure detecting means detects air pressure with respect to the first space in a second period in which air is discharged from the first space by the supply / discharge means;
The control means derives a time decrease rate of the air pressure with respect to the first space in the pressing based on a detection result of the air pressure with respect to the first space in the second period, and the derived time decrease rate is less than a predetermined threshold value. The liquid supply apparatus according to any one of claims 1 to 3, wherein the driving unit is controlled when it is small. The liquid supply apparatus according to claim 1, wherein the first space is in contact with the piston and the liquid surface of the liquid. A liquid discharge apparatus comprising: a liquid discharge head that presses a liquid and discharges the liquid into a droplet; and a liquid supply device that presses the liquid and supplies the liquid to the liquid discharge head,
The liquid discharge head is
A first member that presses the liquid;
A second member disposed opposite to the first member and forming a storage chamber in which liquid is stored together with the first member;
It is arrange | positioned between the said 1st member and the said 2nd member, prescribes | regulates the outer peripheral part of the said storage chamber, is pressed by the said 2nd member side by the said 1st member, and is elastically deformed of the said storage chamber. An elastic member for increasing or decreasing the volume;
An operation member that elastically deforms the elastic member by displacing the first member relative to the second member in a pressing direction that approaches and separates from the second member;
The liquid supply device includes:
A syringe for storing the liquid;
In the syringe, a piston disposed so as to be separated from the liquid level in the first space in which air is supplied and exhausted;
By being connected to the first space via the piston and supplying air to the first space and discharging air from the first space, and adjusting the air pressure with respect to the first space by the supply and discharge Supply / discharge means for pressing the liquid level of the liquid;
Pressure detecting means for detecting air pressure with respect to the first space;
Driving means for moving the piston in the syringe;
A time change rate of air pressure with respect to the first space in the pressing is derived based on a detection result of the air pressure by the pressure detection unit, and the drive unit is controlled when the derived time change rate is smaller than a predetermined threshold value. And a control means for moving the piston so as to approach the liquid surface of the liquid. A liquid supply method using a liquid supply device that presses and supplies liquid,
The liquid supply device includes a syringe that stores the liquid, and a piston that is disposed in the syringe so as to be separated from a liquid surface of the liquid by a first space in which air is supplied and exhausted. ,
The liquid supply method includes:
A pressing step of supplying air to the first space, discharging air from the first space, and pressing the liquid surface by adjusting an air pressure with respect to the first space by the supply and discharge;
A time change rate of the air pressure with respect to the first space in the pressing is derived, and when the derived time change rate is smaller than a predetermined threshold, the piston is moved so as to approach the liquid level of the liquid in the syringe. A liquid supply method including a moving step.

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