JP2010247075A - Pressure regulating valve and liquid droplet discharge device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure regulating valve which can inhibit damage to be inflicted to a diaphragm. <P>SOLUTION: This pressure regulating valve is connected with a first inner flow path of a liquid droplet discharge head which spews an ink droplet. In addition, the pressure regulating valve comprises a second inner flow path which can accommodate the ink to be supplied to the first inner flow path, the diaphragm which can regulate the pressure of the second inner flow path, and a transparent protecting member which is arranged so as to be opposed to the diaphragm through a gap and has an opening for exposing the space formed between the diaphragm and the protecting member to the atmosphere. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a pressure adjusting valve connected to a droplet discharge head of a droplet discharge device, and a droplet discharge device.

  The droplet discharge device includes a droplet discharge head that ejects ink droplets, and an ink supply mechanism that supplies ink to the droplet discharge head. The ink supply mechanism includes a pressure adjustment valve including a diaphragm as disclosed in Patent Document 1, for example.

JP 2003-211701 A

  In the pressure adjusting valve, if the diaphragm is damaged, the pressure cannot be adjusted satisfactorily, and there is a possibility that a discharge failure of the droplet discharge head occurs.

  An object of an aspect of the present invention is to provide a pressure regulating valve that can suppress damage to a diaphragm. Another object of the present invention is to provide a droplet discharge device that can suppress the occurrence of discharge defects.

  According to the first aspect of the present invention, the second internal flow that is connected to the first internal flow path of the liquid droplet ejection head that ejects ink droplets and can store the ink supplied to the first internal flow path. A transparent passage having an opening for opening the space formed between the diaphragm, a diaphragm capable of adjusting the pressure of the second internal flow path, and the diaphragm with a gap therebetween, and being open to the atmosphere And a protective member.

  According to the first aspect of the present invention, since the protective member that protects the diaphragm is provided, it is possible to prevent the diaphragm from being damaged. Moreover, since the protective member has an opening that opens the space formed between the diaphragm and the atmosphere, the diaphragm can be protected without hindering the function (pressure adjusting operation) of the diaphragm. Moreover, since the diaphragm is transparent, the state of the diaphragm and the like can be visually recognized through the protective member.

  In the first aspect of the present invention, it is possible to employ a configuration in which a flow path forming member that supports the diaphragm and forms the second internal flow path is provided, and the flow path forming member is transparent.

  Thereby, the state of the ink flowing through the second internal flow path formed by the flow path forming member can be visually recognized through the protection member and the flow path forming member. For example, it can be confirmed whether or not bubbles exist in the ink. Therefore, for example, when bubbles are present, it is possible to prevent ink that is not in the initial state from being supplied to the droplet discharge head.

  According to the second aspect of the present invention, a droplet discharge device including the pressure regulating valve of the first aspect is provided.

  According to the second aspect of the present invention, it is possible to eject ink via the pressure regulating valve in which damage to the diaphragm is suppressed. Therefore, a desired pattern can be drawn on the work while suppressing the occurrence of ejection failure.

It is a top view which shows an example of the droplet discharge apparatus which concerns on this embodiment. It is a side view which shows an example of the droplet discharge apparatus which concerns on this embodiment. It is a figure which shows an example of the ink supply mechanism which concerns on this embodiment. It is a figure which shows an example of the ink supply mechanism which concerns on this embodiment. It is a figure which shows an example of the pressure control valve which concerns on this embodiment. It is a figure which shows an example of the pressure control valve which concerns on this embodiment. It is a figure which shows an example of the pressure control valve which concerns on this embodiment. It is a figure which shows an example of the pressure control valve which concerns on this embodiment. It is a figure which shows an example of the pressure control valve which concerns on this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing an example of a droplet discharge device 1 according to the present embodiment, and FIG. 2 is a side view. 3 is a view showing the ink supply mechanism 6, and FIG. 4 is a view showing a part of FIG.

  1, 2, 3, and 4, the droplet discharge device 1 includes a machine base 2, a drawing device 3 that is disposed on the machine base 2 and has a droplet discharge head 11, and a machine base 2. Ink for supplying ink to the drawing device 3 having a chamber device (not shown) arranged on the machine base 2, a maintenance device 5 for maintaining the droplet discharge head 11 and a pressure regulating valve 7 A supply mechanism 6 and a control device 12 that controls the operation of the entire droplet discharge device 1 are provided.

  The drawing device 3, the maintenance device 5, and the ink supply mechanism 6 are disposed in the internal space of the chamber device.

  The drawing device 3 is disposed on the machine base 2 and has a moving mechanism 13 that relatively moves the workpiece W and the droplet discharge head 11. The moving mechanism 13 relatively moves the droplet discharge head 11 and the workpiece W in the X axis direction and the Y axis direction. The moving mechanism 13 includes an X-axis table 51 that supports the workpiece W and moves in the X-axis direction, and a Y-axis table 52 that supports the droplet discharge head 11 and moves in the Y-axis direction. In addition, the drawing apparatus 3 includes measuring devices 53 and 53 that measure the position of the workpiece W.

  The X-axis table 51 includes a set table 56 that includes a holding table 54 that holds the workpiece W, a θ table 55 that rotates the table 54 about the Z axis, and an X that supports the set table 56 so as to be movable in the X-axis direction. An axis slider 57 and an X axis motor (not shown) for driving the X axis slider 57 are included. The workpiece W is held by the holding table 54 and can reciprocate in the X-axis direction, which is the main scanning direction, via the X-axis slider 57.

  The Y-axis table 52 drives a pair of support columns 58, a Y-axis frame 59 supported by both support columns 58 and 58, a Y-axis slider 61 that is movably supported by the Y-axis frame 59, and the Y-axis slider 61. And a main carriage 62 that is supported by the Y-axis slider 61 and on which the droplet discharge head 11 is mounted. The droplet discharge head 11 can reciprocate in the Y-axis direction, which is the sub-scanning direction, via the Y-axis slider 61 together with the main carriage 62.

  When drawing on the workpiece W, the control device 12 makes the droplet discharge head 11 and the workpiece W face each other and moves the workpiece W in the main scanning direction (X-axis direction) using the X-axis table 51. In synchronization with the movement, ink droplets are ejected from the droplet discharge head 11. The control device 12 moves the droplet discharge head 11 in the sub-scanning direction (Y-axis direction) using the Y-axis table 52. Thereby, desired drawing is performed in the drawing area of the workpiece W.

  Further, as shown in FIG. 2, the main carriage 62 is disposed at a slide base 63 fixed to the Y-axis slider 61, a hanging frame 64 provided on the slide base 63, and a lower portion of the hanging frame 64. A θ-axis rotation mechanism 65 and a carriage body 66 disposed at the lower end of the θ-axis rotation mechanism 65 are included. The hanging frame 64 supports the carriage body 66 so as to be rotatable around the θ axis via the θ axis rotating mechanism 65.

  The carriage body 66 includes a sub carriage 67, a head plate 68 supported by the sub carriage 67, a valve plate 69 supported by the sub carriage 67, a tank plate 70 supported by the sub carriage 67, and the sub carriage 67. The mounting plate 71 is opposed to the mounting plate 71 and supported by the θ-axis rotation mechanism 65, and the connecting carriage 72 connects the sub-carriage 67 and the mounting plate 71.

  The head plate 68 supports the plurality of droplet discharge heads 11. The valve plate 69 supports the plurality of pressure regulating valves 7. The tank plate 70 supports a plurality of ink tanks 91.

  The droplet discharge head 11 has a nozzle surface 31 on which a plurality of nozzles 32 for discharging ink droplets (droplets) are arranged. The droplet discharge head 11 has a head internal channel connected to the nozzle 32 and an inlet port 34 connected to the head internal channel.

  In the initial filling step by nozzle suction, the ink is introduced from the inlet 34 of the droplet discharge head 11 and supplied to the head internal flow path. The pressure in the head internal flow path is changed by driving a driving element such as a piezoelectric element (piezo element) provided inside the droplet discharge head 11. By driving the drive element, ink in the head internal flow path is ejected from the nozzle 32.

  Next, the maintenance device 5 will be described with reference to FIG. The maintenance device 5 includes a storage unit 21 that seals the nozzle surface 31 of the droplet discharge head 11 to prevent drying of the nozzle 32 and the nozzle 32 of the droplet discharge head 11 when the droplet discharge device 1 is not in operation. A suction unit 22 for sucking and removing the thickened ink and a wiping unit 23 for wiping off dirt adhering to the nozzle surface 31 of the droplet discharge head 11 are provided. The storage unit 21, the suction unit 22, and the wiping unit 23 are mounted on a moving table 24 that can move on the machine base 2.

  The storage unit 21 has a sealing cap 25 that also functions as a flushing box that receives the discarded discharge of the droplet discharge head 11. The sealing cap 25 can be moved by the elevating mechanism 26. When the droplet discharge apparatus 1 is not in operation, the droplet discharge head 11 moves to the maintenance position 42 on the moving table 24 and is sealed by the sealing cap 25. Thereby, drying of the nozzle 32 is prevented.

  The suction unit 22 has a suction cap 81 that can be in close contact with the nozzle surface 31 of the droplet discharge head 11, a waste liquid tank that collects the waste liquid sucked from the suction cap 81, an upstream end connected to the suction cap 81, and a downstream end A waste liquid passage connected to the waste liquid tank, a suction pump provided in the middle of the waste liquid passage, a fluid detection sensor for detecting ink flowing through the waste liquid passage, and a cap lifting mechanism 86 for raising and lowering the suction cap 81 Have The suction cap 81 is attached to the moving table 24 via a cap lifting mechanism 86.

  The wiping unit 23 has a wiping sheet 41. The wiping unit 23 wipes the nozzle surface 31 of the droplet discharge head 11 while moving the wiping sheet 41.

  Next, the ink supply mechanism 6 according to the present embodiment will be described with reference to FIG. The ink supply mechanism 6 includes an ink tank 91, a pressure adjustment valve 7, a tank side tube 92 that connects the ink tank 91 and the pressure adjustment valve 7, and a head that connects the pressure adjustment valve 7 and the droplet discharge head 11. Side tube 93.

  Of the ink tank 91, the pressure adjusting valve 7, the tank side tube 92, and the head side tube 93, the ink tank 91 is disposed at the highest position, and the droplet discharge head 11 is disposed at the lowest position. The ink in the ink tank 91 flows in the order of the tank side tube 92, the pressure adjustment valve 7, and the head side tube 93 and is supplied to the droplet discharge head 11.

  The ink in the ink tank 91 is decompressed to a predetermined pressure by the pressure adjustment valve 7 and supplied to the droplet discharge head 11.

  As shown in FIG. 3, the ink tank 91 is of a cartridge type and includes an ink pack 94 that stores degassed ink and a substantially square cartridge case 95 that stores the ink pack 94. The ink pack 94 is provided with a cylindrical resin supply port 97 on a bag-like one in which two film sheets 96 are overlapped and heat-sealed. The supply port 97 of the ink pack 94 and the tank side tube 92 are connected via a dedicated connector 101.

  As shown in FIG. 4, the connector 101 includes a tube connector 102 that is directly connected to the tank side tube 92, a tank connector 103 that is connected to the ink tank 91, and a connector stand 104 that supports these. Have. A flow path for supplying ink from the ink pack 94 to the tank side tube 92 is formed inside the connection portions 102 and 103. The tube connecting part 102 is constituted by a threaded joint, and the tank connecting part 103 is constituted by a connecting needle 108 having a flow path formed in the axial center.

  The connecting needle 108 has a sharp tip, and a plurality of minute inflow holes (not shown) connected to the internal flow path (not shown) are formed at the tip. That is, the connection needle 108 is connected to the ink pack 94 by being inserted through the rubber plug 99 of the supply port 97 and causes the ink to flow out of the ink pack 94 to form a flow path.

  Similar to the ink pack 94 described above, the tank side tube 92 and the head side tube 93 have a laminated structure in consideration of corrosion resistance, gas non-permeability, waterproofness, and the like. For example, when water-based ink is used, a tube having a five-layer structure in which a polyethylene layer, an adhesive layer, an ethylene vinyl alcohol copolymer layer, an adhesive layer, and a polyethylene layer are sequentially laminated from the inside is used. When the ink of the system is used, a tube having a three-layer structure in which an ethylene vinyl alcohol copolymer layer, an adhesive layer, and a polyethylene layer are sequentially laminated from the inside is used. Polyethylene is a waterproof material, and ethylene vinyl alcohol copolymer is a gas-impermeable material.

  Next, the pressure regulating valve 7 according to the present embodiment will be described with reference to FIGS. 5, 6, 7, 8, and 9.

  The pressure regulating valve 7 is provided inside the valve housing 121 and communicates with the primary chamber 122 connected to the ink tank 91, the secondary chamber 123 connected to the droplet discharge head 11, and the primary chamber 122 and the secondary chamber 123. And a communication channel 124.

  That is, the primary chamber 122, the communication channel 124, and the secondary chamber 123 are connected to the head internal channel of the droplet discharge head 11 that ejects ink droplets via the head side tube 92. An internal flow path that can accommodate the ink supplied to the path is configured. The valve housing 121 functions as a flow path forming member that forms the internal flow path.

  As shown in FIG. 8, the valve housing 121 includes a primary chamber housing 141 for forming the primary chamber 122, a secondary chamber housing 161 for forming the secondary chamber 123, and a ring that supports the diaphragm 125. Plate 131.

  The secondary chamber 123 is formed by a secondary chamber housing 161 and a diaphragm 125. The secondary chamber housing 161 supports the diaphragm 125. At least a part of the diaphragm 125 is disposed so as to face the secondary chamber 123.

  In the present embodiment, the diaphragm 125 is supported by a ring plate 131 that is fixed to the secondary chamber housing 161. The secondary chamber housing 161 and the ring plate 131 may be integrated.

  A valve body 126 that is opened and closed by a diaphragm 125 is provided in the communication channel 124. The ink introduced from the ink tank 91 into the primary chamber 122 is supplied to the droplet discharge head 11 through the secondary chamber 123. At that time, the diaphragm 125 adjusts the pressure of the secondary chamber 123 by opening and closing the valve body 126 provided in the communication flow path 124 using the atmospheric pressure as the adjustment reference pressure.

  As described above, the diaphragm 125 can adjust the pressure of at least a part of the internal flow path formed by the valve housing 121 (secondary chamber 123 in this embodiment).

  Since the pressure regulating valve 7 is used in a vertical position as shown in FIG. 6, the front side of the paper is “up”, the front side is “down”, the left side is “front” and the right side, as shown in FIG. Let's proceed with the explanation as “after”. In these drawings, the pressure adjusting valve 7 is attached to a frame or the like with a mounting plate 127, the inflow connector 128 (union joint) for connecting the tank side tube 92, and the head side tube 93. The outflow connector 129 (union joint) for connecting is shown.

  In the present embodiment, the valve housing 121 includes a primary chamber housing 141, a secondary chamber housing 161, and a ring plate 131, and each is transparent. That is, the valve housing 121 that supports the diaphragm 125 and forms the primary chamber 122, the communication channel 124, and the secondary chamber 123 is transparent.

  In the present embodiment, the valve housing 121 is formed of a transparent synthetic resin that is resistant to ink.

  The primary chamber housing 141, the secondary chamber housing 161, and the ring plate 131 are overlapped with the secondary chamber housing 161 from the front and the rear by overlapping the ring plate 131 and the primary chamber housing 141 with a plurality of stepped parallel pins, etc. After positioning, they are assembled so as to be screwed, and all have an appearance that is concentric with an axis passing through the center of the circular diaphragm 125.

  The primary chamber housing 141 and the secondary chamber housing 161 are joined via an O-ring 133, and the secondary chamber housing 161 and the ring plate 131 are joined via an edge of the diaphragm 125 and a packing 134. . The primary chamber housing 141 and the secondary chamber housing 161 can be formed integrally.

  The primary chamber housing 141 is formed with a truncated cone (substantially cylindrical) primary chamber 122 concentric with the diaphragm 125, and the inner peripheral wall 142 of the primary chamber 122 slightly expands rearward. Tapered surface. An inflow port 143 and a primary chamber air vent port 144 (primary chamber side air vent portion) connected to the ink tank 91 are formed in the upper boss portion 113 formed at the upper back of the primary chamber 122 housing. . The primary chamber air vent port 144 extends in the vertical direction, and the primary chamber air vent port 145 opened to the primary chamber 122 has a top 152 on the inner peripheral surface of the rear portion of the primary chamber 122 serving as an air reservoir. Is open. A lid 146 is screwed into the illustrated primary chamber air vent port 144. However, when an air tube (not shown) is connected, a connector (joint) is screwed in place of the lid 146. Will be.

  As shown in FIG. 6, the inflow port 143 communicates the inlet 147 that opens to the outer peripheral surface of the primary chamber housing 141 and the primary chamber side opening 149 that opens to the upper end 153 of the primary chamber 122. The inflow channel 148 is formed obliquely in the circumferential direction so as to have a predetermined downward gradient. An inflow connector 128 is screwed into the inflow port 147 from the axial direction of the inflow channel 148, and the tank side tube 92 is connected to the inflow port 148 through the inflow connector 128. The internal flow path of the inflow connector 128 is formed so as to expand at the downstream end 154 so that a step portion does not occur in the internal flow path and a large change in the ink flow rate does not occur. The primary chamber-side opening 149 opens at a position adjacent to the primary chamber air vent 145, that is, a position away from the top 152 of the primary chamber 122 in the circumferential direction. The ink flowing in from the ink tank 91 flows down obliquely according to the gradient of the inflow channel 148, and flows into the primary chamber 122 from the primary chamber side opening 149 along the inner peripheral wall 142 of the primary chamber 122. Note that the volume of the primary chamber 122 is sufficiently smaller than the volume of the secondary chamber 123, and ink accumulation is less likely to occur in the primary chamber 122.

  A first annular groove 150 having a rectangular cross section is formed outside the primary chamber 122 on the front surface of the primary chamber 122 housing, which is in close contact with the secondary chamber housing 161. A ring 133 is inserted. Further, the lower portion of the primary chamber housing 141 is cut out in an arcuate shape, and an outflow connector 129 to be described later is disposed in the missing portion.

  The secondary chamber housing 161 has a truncated cone (substantially cylindrical) main chamber 163 with an open front surface for attaching the diaphragm 125, and a truncated cone shape that is connected to the rear of the main chamber 163 and expands toward the main chamber 163 side. The spring chamber 164 and the communication channel 124 communicating the spring chamber 164 and the primary chamber 122 are formed. The main chamber 163, the spring chamber 164, and the communication channel 124 all have a circular cross section concentric with the diaphragm 125. However, the communication flow path 124 includes a circular cross-section shaft insertion portion 165 in which a shaft portion 117 of a valve body 126 described later is slidably accommodated, and a cross-shaped cross-section flow extending from the shaft free insertion portion 165 in four radial directions. It is comprised with the road part 166. FIG. In addition, an annular shallow groove 168 is formed on the front surface of the secondary chamber housing 161 so as to face a fixing groove 167 for a packing 134 described later. Since the packing 134 itself has elasticity, the shallow groove 168 is not necessarily formed.

  The inner peripheral wall 162 of the main chamber 163 has a tapered surface 176 that greatly expands forward so as to follow the negative deformation of the diaphragm 125, and the secondary chamber air vent port 169 ( The secondary chamber side air vent part) and the outflow port 171 are formed vertically. The secondary chamber air vent port 169 is formed in an inclined boss portion 177 formed on the upper back surface (upper rear surface) of the secondary chamber housing 161 and extends slightly inclined in the vertical direction. The secondary chamber air vent port (hole) 173 of the secondary chamber air vent port 169 opened to the secondary chamber 123 opens to the top portion 174 including the tapered surface 176 of the front inner peripheral surface of the secondary chamber 123 serving as an air reservoir. is doing. Also in this case, the lid 146 is screwed into the illustrated secondary chamber air vent port 169, but when an air tube is connected, a connector (joint) (not shown) is used instead of the lid 146. It will be screwed.

  The outflow port 171 is formed in an inclined boss portion 177 located at the lower back of the secondary chamber housing 161, and has an outlet 178 opened at the lower back of the secondary chamber housing 161 and a lower end 175 of the secondary chamber 123 ( A secondary chamber side opening 179 that opens to the bottom of the valley) and an outflow channel 180 that communicates these. The outflow channel 180 is formed obliquely in the front-rear direction so as to have a predetermined downward gradient substantially perpendicular to the tapered surface 176. The outflow connector 129 is screwed into the outflow port 178 from the axial direction of the outflow channel 180, and the head side tube 93 is connected through the outflow connector 129. The internal flow path of the outflow connector 129 is formed so as to expand at the upstream end 155 so that a step portion does not occur in the internal flow path and a large change in the flow rate of ink does not occur. The secondary chamber side opening 179 opens to the full width of the inclined surface with respect to the tapered surface 176 including the valley portion 158 of the secondary chamber 123. The ink flowing out from the secondary chamber 123 flows obliquely from the secondary chamber side opening 179 according to the gradient of the outflow channel 180 and flows out to the droplet discharge head 11 side.

  The ring plate 131 sandwiches and fixes the diaphragm 125 between the front surface of the secondary chamber housing 161, and a fixing groove 167 for the packing 134 in contact with the edge of the diaphragm 125 is formed on the inner surface of the secondary chamber side. Is formed.

  The diaphragm 125 is composed of a diaphragm main body 115 made of a resin film 114 and a resin pressure receiving plate 116 attached to the inside of the diaphragm main body 115. The pressure receiving plate 116 is formed in a disk shape concentric with the diaphragm main body 115 and has a sufficiently small diameter with respect to the diaphragm main body 115, and a shaft portion 117 of a valve body 126 (to be described later) abuts on the center thereof. The diaphragm main body 115 is configured by stacking heat-resistant PP (polypropylene), special PP, and PET (polyethylene terephthalate) on which silica is vapor-deposited, and is formed in a circular shape having the same diameter as the front surface of the secondary chamber housing 161. . The diaphragm 125 is hermetically fixed to the front surface of the secondary chamber housing 161 by a ring plate 131 together with a packing 134 attached to the diaphragm 125 from the outside. The pressure receiving plate 116 may be provided outside the diaphragm 125. However, since a shaft portion 117 of a valve body 126 to be described later repeats separation and contact, the pressure receiving plate 116 is provided inside in this embodiment to prevent the diaphragm 125 from being damaged. Yes.

  The valve body 126 is provided (adhered) to a disc-shaped valve body main body 201, a shaft portion 117 extending in one direction from the center of the valve body main body 201, and the shaft portion 117 side (front surface) of the valve body main body 201. And an annular valve seal 202. The valve body main body 201 and the shaft portion 117 are integrally formed of a corrosion-resistant material such as stainless steel, and an annular small protrusion 203 is formed on the front surface of the valve body main body 201 so as to be located outside the shaft portion 117. Yes. The valve seal 202 is made of, for example, soft silicon rubber, and a seal protrusion 204 serving as an annular protrusion projects from the front surface of the valve seal 202 corresponding to the small protrusion 203 described above. For this reason, when the valve body 126 is closed, the seal projection 204 strongly contacts the back surface of the secondary chamber housing 161 serving as a valve seat, that is, the opening edge of the communication channel 124, so that the communication channel 124 becomes the primary chamber 122. Clogged liquid-tight from the side.

  The shaft portion 117 is slidably disposed in the communication flow path 124 and abuts against the pressure receiving plate 116 of the diaphragm 125 whose front end (front end) is in a neutral position in a valve-closed state. That is, in the state of plus deformation in which the diaphragm 125 bulges outward, a predetermined gap is generated between the front end of the shaft portion 117 and the pressure receiving plate 116, and the diaphragm 125 is deformed to the minus side from this state. As a result, when the front end of the shaft portion 117 and the pressure receiving plate 116 come into contact with each other in a neutral state parallel to the ring plate 131, and when the diaphragm 125 is further deformed negatively, the pressure receiving plate 116 passes through the shaft portion 117. The main body 201 is pushed and opened. Accordingly, of the volume of the secondary chamber 123, the volume of the volume in which the diaphragm 125 becomes neutral from the plus deformation is supplied with ink without receiving any pressure on the primary chamber side.

  On the other hand, a valve body biasing spring 206 that biases the valve body 126 in the secondary chamber side, that is, in the valve closing direction is interposed between the back surface of the valve body 126 and the rear wall of the primary chamber 122. ing. Similarly, a pressure receiving plate urging spring 207 is provided between the pressure receiving plate 116 and the spring chamber 164 of the secondary chamber 123 to urge the diaphragm main body 115 toward the outside via the pressure receiving plate 116. In this case, the valve body urging spring 206 complements the water head of the functional liquid tank 91 applied to the back surface of the valve body 126, and the hydraulic force of the functional liquid tank 91 and the spring force of the valve body urging spring 206 The valve body 126 is pressed in the closing direction. On the other hand, the pressure receiving plate urging spring 207 complements plus deformation of the diaphragm 125, and acts so that the secondary chamber 123 is slightly negative with respect to atmospheric pressure.

  The pressure regulating valve 7 opens and closes due to the pressure balance between the secondary chamber 123 connected to the atmospheric pressure and the droplet discharge head 11, and the valve body 126 opens and closes. At this time, the valve body biasing spring 206 and the pressure receiving plate biasing spring 207 are opened. The valve body 126 opens and closes very slowly by the valve seal 202 (elastic force) of soft silicone rubber. For this reason, pressure fluctuation (cavitation) due to opening and closing of the valve body 126 is suppressed, and the ejection driving of the droplet ejection head 11 is not affected. Of course, the pulsation and the like generated on the ink tank side (primary side) are also cut off by the valve body 126 and can be absorbed (damper function).

  The mounting plate 127 is made of a stainless steel plate and is fixed to the rear side surface of the secondary chamber housing 161. On both surfaces of the mounting plate 127, a linear mark 208 indicating the center position of the diaphragm 125 is engraved at an intermediate position between the upper and lower sides. It is used as an index when installing with a difference in height.

  In the present embodiment, for example, as shown in FIGS. 7 and 8, the pressure regulating valve 7 is disposed so as to face the diaphragm 125 through a gap, and the space formed between the diaphragm 125 is opened to the atmosphere. A transparent protective member 300 having an opening 301 is provided. The protection member 300 is made of, for example, a transparent synthetic resin.

  In the present embodiment, the protection member 300 is larger than the ring plate 131 and is fixed to the ring plate 131.

  Thereby, the diaphragm 125 can be protected without interfering with the pressure adjustment operation of the diaphragm 125. Therefore, damage to the diaphragm 125 can be suppressed.

  In the present embodiment, the protection member 300 is transparent. Therefore, the state of the diaphragm 125 and the state of the valve housing 121 (secondary chamber housing 161, ring plate 131, etc.) can be confirmed (viewed) via the protective member 300. That is, the state of the diaphragm 125 and the state of the valve housing 121 can be confirmed through the protective member 300 without removing the protective member 300 from the ring plate 131.

  In this embodiment, since the valve housing 121 is also transparent, the state of the ink flowing through the internal flow path (primary chamber 122, secondary chamber 123, communication flow path 124, etc.) of the valve housing is confirmed from the outside ( Visual recognition). For example, it can be confirmed whether or not bubbles are present in the ink in the internal flow path of the valve housing.

  As described above, according to the present embodiment, the diaphragm 125 can be protected by providing the protection member 300. Therefore, it is possible to prevent the diaphragm 125 from being damaged.

  Moreover, in this embodiment, since the diaphragm 125 is transparent, the state of the diaphragm 125 and the state of the valve housing 121 can be visually recognized from the outside.

  In the present embodiment, since the valve housing 121 is transparent, the state of the ink flowing through the internal flow path of the valve housing 121 can be visually recognized from the outside.

  DESCRIPTION OF SYMBOLS 1 ... Droplet discharge apparatus, 7 ... Pressure control valve, 11 ... Droplet discharge head, 121 ... Valve housing (flow path formation member), 122 ... Primary chamber (2nd internal flow path), 123 ... Secondary chamber ( 2nd internal flow path), 124 ... Communication flow path (2nd internal flow path), 125 ... Diaphragm, 300 ... Protection member, 301 ... Opening

Claims (3)

A second internal flow path that is connected to a first internal flow path of a liquid droplet ejection head that ejects ink droplets and can store ink supplied to the first internal flow path;
A diaphragm capable of adjusting the pressure of the second internal flow path;
And a transparent protective member that is disposed so as to face the diaphragm with a gap and has an opening that opens the space formed between the diaphragm and the atmosphere. While supporting the diaphragm, comprising a flow path forming member that forms the second internal flow path,
The pressure regulating valve according to claim 1, wherein the flow path forming member is transparent.   A droplet discharge device comprising the pressure regulating valve according to claim 1.

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