JP2018089949A - Liquid circulation device, device for discharging liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a liquid flow rate even if the inner diameter of a bubble discharge path is reduced without obstructing the flow of liquid by bubbles. SOLUTION: A first manifold 241 is provided with two first bubble discharge paths (301A, 301B) for discharging bubbles from a first manifold 241 to a second manifold 251 at both ends in a longitudinal direction, and a second manifold is provided. The 251 is provided with two second bubble discharge paths (302A, 302B) for discharging bubbles from the second manifold 251 to the outside of the second manifold 251 at both ends in the longitudinal direction, and the two second bubble discharge paths are The common bubble discharge path 303 is integrated into one common bubble discharge path 303, and the outlet of the common bubble discharge path 303 leads to the gas chamber 221a of the second sub tank 221. [Selection diagram] FIG. 5

Description

  The present invention relates to a liquid circulation device and a device for discharging liquid.

  In an apparatus using a liquid discharge head (hereinafter, also simply referred to as “head”), if bubbles are mixed in the head, a discharge failure occurs. Therefore, a flow-through head (circulation type head) is used, and the liquid is discharged. The air bubbles are discharged by circulating.

  Conventionally, a liquid supply manifold connected to a plurality of circulation type heads on the supply side, a liquid recovery manifold connected to the discharge side of the head, and a first bypass flow path connecting between the liquid supply manifold and the liquid recovery manifold, A liquid circulation means for circulating the liquid, and a second bypass flow path connecting between the liquid supply manifold and the liquid recovery manifold, and the liquid supply manifold and the liquid recovery manifold each contain a gas mixed in the liquid. One end of the first bypass channel is connected to the upper side in the vertical direction of the end of the liquid supply manifold opposite to the side on which the liquid inlet is formed. And one end of the second bypass flow path is connected to the lower side in the vertical direction of the end of the liquid supply manifold opposite to the side where the liquid inlet is formed. In addition, there is a configuration in which the other end of the second bypass channel is connected to the lower side in the vertical direction of the end of the liquid recovery manifold opposite to the side where the liquid outlet is formed (Patent Document). 1).

Japanese Patent No. 5536410

  However, in the configuration disclosed in Patent Document 1, since the liquid supply manifold is disposed above the liquid recovery manifold, it is difficult for bubbles to move. Further, since the bubbles are discharged through the same flow path as the liquid, there is a possibility that the flow of the liquid is hindered by the bubbles. In this case, there is a problem that if the flow path diameter is increased to ensure the flow rate, bubbles do not peel off the meniscus in the flow path, the bubbles do not flow, and if the flow path diameter is reduced, the liquid flow rate cannot be secured.

  The present invention has been made in view of the above problems, and an object of the present invention is to improve bubble discharge performance without inhibiting the flow of liquid.

In order to solve the above problems, a liquid circulation device according to the present invention is
A circulation path through which the liquid circulates via a liquid discharge head;
In the circulation path, an upstream manifold that leads to the supply ports of a plurality of liquid ejection heads,
A downstream manifold that leads to a discharge port side of the plurality of liquid discharge heads;
A discharge side flow path for discharging the liquid in the downstream side manifold,
A bubble discharge path for discharging bubbles in the downstream manifold is provided separately from the discharge channel.

  According to the present invention, it is possible to improve bubble discharge performance without hindering the flow of liquid.

It is a schematic explanatory drawing of an example of the apparatus which discharges the liquid which concerns on this invention. It is a plane explanatory view of an example of a head unit of the device. 2 is an external perspective view illustrating an example of a liquid discharge head. FIG. It is sectional explanatory drawing of the direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the head. It is block explanatory drawing with which description of the part (liquid circulation apparatus) which concerns on the liquid supply circulation in 1st Embodiment of this invention is provided. It is a block diagram with which it uses for description of the outline | summary of the part which concerns on the supply circulation control of the control part in the embodiment. It is block explanatory drawing with which description of the part (liquid circulation apparatus) which concerns on the liquid supply circulation in 2nd Embodiment of this invention is provided. It is block explanatory drawing with which description of the part (liquid circulation apparatus) which concerns on the liquid supply circulation in 3rd Embodiment of this invention is provided. It is block explanatory drawing with which it uses for description of the part (liquid circulation apparatus) which concerns on the liquid supply circulation in 4th Embodiment of this invention. It is block explanatory drawing with which it uses for description of the part (liquid circulation apparatus) which concerns on the liquid supply circulation in 5th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an example of an apparatus for discharging a liquid according to the present invention will be described with reference to FIGS. FIG. 1 is a schematic explanatory view of the apparatus, and FIG. 2 is a plan explanatory view of an example of a head unit of the apparatus.

  The printing apparatus 1000 which is an apparatus for discharging the liquid includes a carry-in means 1 for carrying in the continuous body 10, a guide carrying means 3 for guiding and carrying the continuous body 10 carried from the carry-in means 1 to the printing means 5, and a continuous body. The printer 10 includes a printing unit 5 that performs printing to form an image by discharging liquid, a drying unit 7 that dries the continuous body 10, and a discharge unit 9 that discharges the continuous body 10.

  The continuous body 10 is sent out from the original winding roller 11 of the carry-in means 1 and guided and conveyed by the rollers of the carry-in means 1, the guide conveyance means 3, the drying means 7 and the discharge means 9, and the take-up roller 91 of the discharge means 9. It is wound up by.

  The continuum 10 is conveyed on the conveyance guide member 59 by the printing unit 5 so as to face the head unit 50 and the head unit 55, and an image is formed by the liquid ejected from the head unit 50. Post-processing is performed with the processing liquid.

  Here, the head unit 50 includes, for example, full-line head arrays 51K, 51C, 51M, 51Y for four colors from the upstream side in the medium conveyance direction (hereinafter referred to as “head array 51” when colors are not distinguished). ) Is arranged.

  Each head array 51 is a liquid ejecting unit, and ejects black K, cyan C, magenta M, and yellow Y liquid to the transported continuous body 10, respectively. The type and number of colors are not limited to this.

  For example, as shown in FIG. 2, the head array 51 is configured by arranging liquid ejection heads (also simply referred to as “heads”) 100 in a staggered manner on a base member 52, but is not limited thereto. Absent.

  Next, an example of the liquid discharge head will be described with reference to FIGS. FIG. 3 is an external perspective explanatory view of the liquid discharge head, and FIG. 4 is a cross-sectional explanatory view in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the head.

  In the liquid discharge head, a nozzle plate 101, a flow path plate 102, and a vibration plate member 103 as a wall surface member are laminated and joined. A piezoelectric actuator 111 that displaces a vibration region (vibration plate) 130 of the diaphragm member 103, a common liquid chamber member 120 that also serves as a frame member of the head, and a cover 129 are provided. A portion constituted by the flow path plate 102 and the vibration plate member 103 is referred to as a flow path member 140.

  The nozzle plate 101 has a plurality of nozzles 104 that discharge liquid.

  The flow path plate 102 penetrates into the individual liquid chamber 106 that communicates with the nozzle 104 via the nozzle communication path 105, the supply side fluid resistance portion 107 that communicates with the individual liquid chamber 106, and the liquid introduction portion 108 that communicates with the supply side fluid resistance portion 107. Holes and grooves are formed. The nozzle communication path 105 is a flow path that communicates with the nozzle 104 and the individual liquid chamber 106 respectively. In addition, the liquid introduction unit 108 communicates with the supply-side common liquid chamber 110 through the opening 109 of the diaphragm member 103.

  The vibration plate member 103 has a deformable vibration region 130 that forms a wall surface of the individual liquid chamber 106 of the flow path plate 102. Here, the diaphragm member 103 has a two-layer structure (not limited), and is formed of a first layer that forms a thin portion and a second layer that forms a thick portion from the flow path plate 102 side. A deformable vibration region 130 is formed in a portion corresponding to the individual liquid chamber 106.

  A piezoelectric actuator 111 including an electromechanical conversion element as a driving means (actuator means, pressure generating means) for deforming the vibration region 130 of the diaphragm member 103 on the opposite side of the diaphragm member 103 from the individual liquid chamber 106. Is arranged.

  In this piezoelectric actuator 111, a piezoelectric member joined on a base member 113 is grooved by half-cut dicing to form a required number of columnar piezoelectric elements 112 in a comb-like shape at a predetermined interval.

  And the piezoelectric element 112 is joined to the convex part 130a which is an island-like thick part formed in the vibration area 130 of the diaphragm member 103. A flexible wiring member 115 is connected to the piezoelectric element 112.

  The common liquid chamber member 120 forms a supply side common liquid chamber 110 and a discharge side common liquid chamber 150. The supply side common liquid chamber 110 communicates with the supply port 171, and the discharge side common liquid chamber 150 communicates with the discharge side port 181.

  Here, the common liquid chamber member 120 is constituted by a first common liquid chamber member 121 and a second common liquid chamber member 122, and the first common liquid chamber member 121 is placed on the diaphragm member 103 side of the flow path member 140. The second common liquid chamber member 122 is laminated and bonded to the first common liquid chamber member 121.

  The first common liquid chamber member 121 forms a downstream common liquid chamber 110 </ b> A that is a part of the supply-side common liquid chamber 110 that communicates with the liquid introduction unit 108, and a discharge-side common liquid chamber 150 that communicates with the discharge flow channel 151. ing. The second common liquid chamber member 122 forms an upstream common liquid chamber 110 </ b> B that is the remaining part of the supply side common liquid chamber 110.

  Further, the flow path plate 102 is formed with a discharge flow path 151 along the surface direction of the flow path plate 102 that communicates with each individual liquid chamber 106 via the nozzle communication path 105. The discharge channel 151 communicates with the discharge side common liquid chamber 150.

  In this liquid ejection head, for example, the voltage applied to the piezoelectric element 112 is lowered from the reference potential (intermediate potential), so that the piezoelectric element 112 contracts, and the vibration region 130 of the diaphragm member 103 is drawn, so that the volume of the individual liquid chamber 106 is increased. As the liquid expands, the liquid flows into the individual liquid chamber 106.

  Thereafter, the voltage applied to the piezoelectric element 112 is increased to extend the piezoelectric element 112 in the stacking direction, and the vibration region 130 of the diaphragm member 103 is deformed in the direction toward the nozzle 104 to contract the volume of the individual liquid chamber 106. As a result, the liquid in the individual liquid chamber 106 is pressurized, and the liquid is discharged from the nozzle 104.

  Further, the liquid that is not discharged from the nozzle 104 passes through the nozzle 104 and is discharged from the discharge flow channel 151 to the discharge side common liquid chamber 150, and is again supplied from the discharge side common liquid chamber 150 to the supply side common liquid chamber 110 through the external circulation path. Supplied.

  Note that the driving method of the head is not limited to the above example (drawing-pushing), and it is also possible to perform striking or pushing depending on the direction to which the drive waveform is given.

  Next, a portion (liquid circulation device) related to the liquid supply circulation in the first embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram for explaining the same.

  The liquid circulation device 200 includes a main tank 201 that is a liquid storage unit that stores liquid discharged from the head 100, a first sub tank 211 that is an upstream sub tank, a second sub tank 221 that is a downstream sub tank, and an intermediate sub tank. The third sub tank 231 is provided.

  In addition, the first liquid feed pump 202 that sends liquid from the third sub tank 231 to the first sub tank 211, the second liquid feed pump 203 that sends liquid from the second sub tank 221 to the third sub tank 231, and the third tank from the main tank 201 to the third sub tank 231. A third liquid feed pump 204 for feeding liquid to the sub tank 231 is provided.

  In addition, a first manifold 241 that is an upstream manifold through which a plurality of heads 100 communicate, a second manifold 251 that is a downstream manifold, a pressurized head tank 261 and a decompressed head tank 262 for each head 100, and dissolved in liquid A degassing device 270 is provided as degassing means for removing gas.

  Here, a third sub-tank 231 is disposed between the first sub-tank 211 and the second sub-tank 221, and the third liquid feed pump 204 passes through a liquid path 283 including the filter 205 and the electromagnetic valve 206 from the main tank 201. Liquid is fed (supplied) to the 3 sub tank 231.

  The third sub-tank 231 includes a liquid level detection unit 232 and an electromagnetic valve 233 that constitutes an atmosphere release mechanism that opens the interior to the atmosphere.

  The third sub tank 231 and the first sub tank 211 are connected through a liquid path 281, and the first liquid feed pump 202 is provided in the liquid path 281. The liquid path 281 is provided with a backflow liquid path 284 that bypasses the first liquid feed pump 202, and the backflow liquid path 284 is provided with an electromagnetic valve 285.

  The third sub tank 231 and the second sub tank 221 are connected through a liquid path 282, and the second liquid pump 203 is provided in the liquid path 282. The liquid path 282 is provided with a backflow liquid path 286 that bypasses the second liquid feeding pump 203, and the backflow liquid path 286 is provided with an electromagnetic valve 287.

  The first sub tank 211 has a gas chamber 211a, and is configured so that liquid and gas coexist. The first sub tank 211 is provided with a liquid level detecting means 212 for detecting the liquid level and an electromagnetic valve 213 serving as an atmospheric release mechanism for releasing the inside to the atmosphere.

  The second sub-tank 221 has a gas chamber 221a and has a configuration in which liquid and gas coexist. The second sub tank 221 is provided with a liquid level detecting means 222 for detecting the liquid level and an electromagnetic valve 223 serving as an atmospheric release mechanism for releasing the inside to the atmosphere.

  The first sub tank 211 is connected to the first manifold 241 through a liquid path 291 including a deaeration device 270 and a filter 271. The liquid path 291 is provided with an electromagnetic valve 273 that opens and closes the liquid path 291 and a pressure sensor 274 that detects the pressure in the liquid path 291.

  The first manifold 241 communicates with the supply port 171 (supply port) side of the head 100 via a supply path 242. The supply path 242 is connected to the supply port 171 of the head 100 via the pressurized head tank 261. The supply path 242 is provided with an electromagnetic valve 243 that opens and closes the path upstream of the pressure head tank 261.

  The second sub tank 221 is connected to the second manifold 251 through the liquid path 292. The liquid path 292 is provided with an electromagnetic valve 275 that opens and closes the liquid path 292 and a pressure sensor 276 that detects the pressure in the liquid path 292.

  The second manifold 251 communicates with the discharge port 181 (discharge port) side of the head 100 via the discharge path 252. The discharge path 252 is connected to the discharge port 181 of the head 100 via the decompression head tank 262. The discharge path 252 is provided with an electromagnetic valve 253 that opens and closes the path downstream of the decompression head tank 262.

  A connection port (liquid supply port) with the liquid path 291 of the first manifold 241 and a connection port (liquid discharge port) with the liquid path 292 of the second manifold 251 are provided on the same end side in the longitudinal direction. Yes.

  Here, from the third sub tank 231, the liquid path 281, the first sub tank 211, the liquid path 291, the deaeration device 270, the first manifold 241, the head 100, the second manifold 251, the second sub tank 221, and the liquid path 282 are passed. A circulation path is configured by a path returning to the third sub tank 231.

  The first manifold 241 is provided with two first bubble discharge paths 301 (301A and 301B) for discharging bubbles from the first manifold 241 to the second manifold 251 at both ends in the longitudinal direction.

  The second manifold 251 is provided with two second bubble discharge paths 302 (302A, 302B) for discharging bubbles from the second manifold 251 to the outside of the second manifold 251 at both ends in the longitudinal direction.

  The two second bubble discharge paths 302 are combined into one common bubble discharge path 303, and the common bubble discharge path 303 has an outlet communicating with the gas chamber 221 a of the second sub tank 221.

  In other words, the bubble discharge path configured by the first bubble discharge path 301, the second bubble discharge path 302, and the common bubble discharge path 303 is a route different from the circulation path. Note that the “different system route” means a route (sub route) different from the liquid circulation route (main route). Unlike the circulation path, the main role is not the circulation of liquid but the discharge of bubbles. However, for example, at the time of air bubble removal at the time of initial filling or at the time of emergency stop, the liquid may flow through a path of another system.

  The two first bubble discharge paths 301 (301A, 301B) are provided with electromagnetic valves 311 (311A, 311B), which are first on-off valves for opening and closing the paths, respectively. Similarly, the two second bubble discharge paths 302 (302A, 302B) are provided with electromagnetic valves 312 (312A, 312B), which are second on-off valves for opening and closing the paths, respectively.

  In addition, the first manifold 241 and the second manifold 251 are arranged at a position where the second manifold 251 is higher than the first manifold 241 in the height direction. The first bubble discharge path 301 is connected to the top surface 241 a side of the first manifold 241, and the second bubble discharge path 302 is connected to the top surface 251 a side of the second manifold 251.

  Next, an outline of a portion related to supply circulation control of the control unit in the present embodiment will be described with reference to FIG. FIG. 6 is a block diagram for the explanation.

  The control unit 500 includes a main control unit 500A including a CPU 501 that controls the entire apparatus, a ROM 502 that stores fixed data such as various programs including programs executed by the CPU 501, and a RAM 503 that temporarily stores image data and the like. ing.

  The control unit 500 includes a rewritable nonvolatile memory 504 for holding data while the apparatus is powered off. The control unit 500 includes an ASIC 505 that processes various signal processing on image data, image processing that performs rearrangement, and other input / output signals for control.

  The control unit 500 includes a print control unit 508 including a data transfer unit for driving and controlling each head 100 of the head unit 50, a driving signal generation unit, and a bias voltage output unit, and a driving IC (for driving each head 100). Here, it is referred to as “head driver”) 509.

  The control unit 500 includes an electromagnetic valve control unit 510 that drives and controls the supply circulation system electromagnetic valve group 550. The supply circulation system solenoid valve group 550 includes solenoid valves 206, 273, 243, 253, and 275 for supply circulation paths, solenoid valves 213, 223, and 233 for opening to the atmosphere, and solenoid valves 285 and 287 for backflow liquid paths. It is.

  The control unit 500 includes an electromagnetic valve control unit 520 that drives and controls the bubble discharge system electromagnetic valve group 560. The bubble discharge system solenoid valve group 560 includes solenoid valves 311A, 311B, 312A, and 312B.

  The control unit 500 includes a supply system control unit 511 that drives and controls the third liquid feeding pump 204.

  The control unit 500 includes a pressure system control unit 512 that drives and controls the first liquid feeding pump 202 and the second liquid feeding pump 203.

  The control unit 500 has an I / O unit 507. The I / O unit 507 can process various sensor information, and obtains detection results from the pressure sensors 274 and 276 and information from various sensor groups 515. Information necessary for controlling the apparatus is extracted and used for control by the print control unit 508, the electromagnetic valve control units 510 and 520, the supply system control unit 511, and the pressure system control unit 512.

  An operation panel 514 for inputting and displaying information necessary for this apparatus is connected to the control unit 500.

  Next, a liquid circulation method in the liquid circulation device of this embodiment will be described.

(1) Liquid Flow from Main Tank 201 to Third Subtank 231 When the liquid level detection means 232 detects that the third subtank 231 is short of liquid, the third liquid feed pump 204 is driven and the liquid path 283 from the main tank 201. Then, the liquid is supplied to the third sub tank 231 until the liquid level becomes full according to the detection result of the liquid level detection means 232.
(2) Liquid flow from the third sub-tank 231 to the first sub-tank 211 The first liquid feed pump 202 is driven to send liquid from the third sub-tank 231 to the first sub-tank 211 via the liquid path 281. it can.
(3) Liquid flow from the second sub tank 221 to the third sub tank 231 The second liquid feed pump 203 is driven to supply liquid from the second sub tank 221 to the third sub tank 231 via the liquid path 282. it can.

(4) Liquid flow in the first sub-tank 211-circular head 100-second sub-tank 221 The first liquid feed pump 202 is driven until the pressure detected by the pressure sensor 274 reaches a target pressure (for example, pressure to be increased). Then, the liquid is supplied to the first sub tank 211. Further, the second liquid feeding pump 203 is driven until the pressure detected by the pressure sensor 276 reaches a target pressure (for example, a negative pressure) to feed the liquid to the third sub tank 231.

  Thereby, a differential pressure is generated between the first sub tank 211 and the second sub tank 221. In response to this differential pressure, the filter 271, the degassing device 270, the first manifold 241, the plurality of supply paths 242, the plurality of head tanks 261, the plurality of heads 100, the plurality of heads from the first sub tank 211 via the liquid path 291. The liquid can be circulated to the second sub tank 221 through the discharge path 25, the plurality of head tanks 262, the second manifold 251, and the liquid path 292.

  Next, the negative pressure formation of the nozzle meniscus will be described.

  Generally, when discharging from the head, the pressure applied to the nozzle meniscus is controlled to a negative pressure. This is to prevent the liquid from overflowing from the nozzle. In addition, when discharging is performed at high speed, fluid inertia may act at the start and end of discharge, and pressure pulsation may occur in the nozzle meniscus. At this time, the pressure on the positive pressure side is temporarily generated, so that the liquid is prevented from overflowing from the nozzle even in such a case.

  When using a circulation type head, a method of setting a positive pressure in the first sub-tank 211 and a negative pressure in the second sub-tank 221 is common.

  For example, the fluid resistance R1 from the first sub tank 211 to the nozzle meniscus in the head 100 and the fluid resistance R2 from the nozzle meniscus to the second sub tank 221 are obtained in advance by calculation or measurement.

  Then, by setting the pressure V1 of the first sub tank 211 and the pressure V2 of the second sub tank 221 according to the fluid resistances R1 and R2, according to the ratio of the fluid resistances R1 and R2 and the values of the pressures V1 and V2. The target negative pressure V can be generated in the nozzle meniscus.

In other words, if the circulating flow rate is I,
V-V1 = I × R1
V2−V = I × R2
It becomes.

Here, by deleting I from both sides and transforming,
V = (V2 + R2 / R2 × V1) / (1 + R2 / R1)
It becomes.

  Therefore, it is understood that the meniscus pressure is determined according to the set pressure and the fluid resistance ratio.

  In the above description, the first sub tank 211 is set to a positive pressure. However, the second sub tank 221 has a negative pressure larger than that of the first sub tank 211 while the first sub tank 211 is set to a negative pressure. By controlling in this way, it can also be set as the structure which generates a differential pressure and circulates a liquid.

  The advantage of this configuration is that the first sub-tank 211 is also at a negative pressure, so that the liquid can be circulated while reducing the risk of liquid dripping compared to the configuration described above.

  Next, the bubble discharging operation will be described.

  In the present embodiment, the bubbles move from the first manifold 241 to the second manifold 251 by opening the electromagnetic valve 311 of the first bubble discharge path 301.

  At this time, air bubbles can be efficiently discharged from the first manifold 241 to the second manifold 251 by arranging the second manifold 251 at a position higher than the first manifold 241. In addition, since the first bubble discharge path 301 communicates with the bottom surface of the second manifold 251, the bubbles can move without staying in the first bubble discharge path 301.

  Further, by opening the electromagnetic valve 312 of the second bubble discharge path 302, the bubbles move from the second manifold 251 to the common bubble discharge path 303 and are discharged to the gas chamber 221 a of the second sub tank 221.

  As described above, the bubbles are discharged by the bubble discharge path (first bubble discharge path 301, second bubble discharge path 302, common bubble discharge path 303) which is a path different from the liquid path.

  Thereby, the flow of the liquid is not hindered by the bubbles. Further, even if the inner diameter of the bubble discharge path is reduced, the inner diameter of the liquid path does not change, so that the liquid flow rate can be ensured.

  Further, by disposing the outlet of the bubble discharge path in the gas chamber 221a of the second sub tank 221, the discharged bubbles can be sent to the gas chamber as they are.

  Further, the first bubble discharge path 301 is connected to both ends of the first manifold 241 in the longitudinal direction, and the second bubble discharge path 302 is connected to both ends of the second manifold 251 in the longitudinal direction. Bubbles can be discharged.

  Here, regarding the order of opening the solenoid valves 311A, 311B, 312A, 312B, first, the solenoid valve 311A on the one end side of the first manifold 241 and the solenoid valve 312B on the other end side of the second manifold 251 are opened. It is preferable.

  That is, the one end side far from the liquid inflow side of the first manifold 241 and the second manifold 251 are connected via the first bubble discharge path 301A, and the other end close to the liquid discharge side of the second manifold 251 and the common bubble discharge. The path 303 communicates with the second bubble discharge path 302B. Here, the “end portion” means a region between the center and the end, and is not limited to the end.

  As a result, a liquid flow can be generated throughout the first manifold 241 and the second manifold 251.

  After opening the solenoid valves 311A and 312B, the solenoid valves 311B and 312B may be opened to continue the bubble discharging operation, or only the solenoid valves 311A and 312B may be opened to continue the bubble discharging operation. .

  In this case, the liquid inflow side of the first manifold 241 and the liquid discharge side of the second manifold 251 are arranged so as to be located on the same side in the longitudinal direction, so that the liquid is spread over the entire area of the first manifold 241 and the second manifold 251. Can be generated.

  Next, the part (liquid circulation apparatus) concerning the liquid supply circulation in 2nd Embodiment of this invention is demonstrated with reference to FIG. FIG. 7 is a block diagram for explaining the same.

  In the present embodiment, one end of the first bubble discharge path 301 communicates with the first manifold 241 at the end opposite to the liquid inflow side, and the other end of the first bubble discharge path 301 is the liquid discharge side of the second manifold 251. The second bubble discharge path 302 communicates with the end of the second manifold 251 on the liquid discharge side.

  Electromagnetic valves 311 and 312 are provided in the first bubble discharge path 301 and the second bubble discharge path 302.

  Even with this configuration, it is possible to generate a liquid flow over the entire area of the first manifold 241 and the second manifold 251 and finally discharge the bubbles from the second bubble discharge path 302 leading to the second manifold 251. it can.

  In the present embodiment, one end of the first bubble discharge path 301 is connected to the first manifold 241 at the end opposite to the liquid inflow side, and the other end of the first bubble discharge path 301 is the liquid of the second manifold 251. The second bubble discharge path 302 communicates with the end of the second manifold 251 on the liquid discharge side and the end opposite to the discharge side.

  Thereby, the number of bubble discharge paths can be reduced as compared with the first embodiment. For example, even when the bubble generation source is on the downstream side of the first manifold 241 (such as the head 100 connected to the most downstream side), the bubbles can be discharged through the bubble discharge path disposed further downstream than the bubble generation source.

  Next, a portion (liquid circulation device) related to the liquid supply circulation in the third embodiment of the present invention will be described with reference to FIG. FIG. 8 is a block diagram for explaining the same.

  In the present embodiment, the first manifold 241 has a ceiling so as to become higher from the liquid inflow end (one end) toward the end (the other end) opposite to the liquid inflow side. The surface 241a is inclined. The first bubble discharge path 301 is connected to the end of the first manifold 241 opposite to the liquid inflow side.

  The other end of the first bubble discharge path 301 is connected to the end of the second manifold 251 opposite to the end on the liquid discharge side.

  The top surface 251a of the second manifold 251 is inclined so as to become higher from the end (one end) side opposite to the liquid discharge side toward the end (other end) side on the liquid discharge side. Yes. The second bubble discharge path 302 is connected to the liquid discharge side of the second manifold 251.

  That is, by inclining the top surfaces 241a and 251a of the first manifold 241 and the second manifold 251 in the longitudinal direction, bubbles can be collected on the other end side by buoyancy. “One end” means an end on the lower side in the inclination, and “the other end” means an end on the higher side in the inclination.

  Thereby, even if the first bubble discharge path and the second bubble discharge path are one path, the bubbles can be reliably discharged, and the configuration becomes simple.

  The configuration in which the top surface is tilted may be either a configuration in which the top surface itself is tilted or a configuration in which the entire manifold is tilted.

  Next, the part (liquid circulation apparatus) which concerns on the liquid supply circulation in 4th Embodiment of this invention is demonstrated with reference to FIG. FIG. 9 is a block diagram for explaining the same.

  In the present embodiment, the second manifold 251 has a top surface so as to become higher from the liquid discharge side end (one end) side toward the end opposite to the liquid discharge side (the other end). 251a is inclined. The second air bubble discharge path 302 is connected to the side opposite to the liquid discharge side of the second manifold 251 (the higher side of the top surface 251a).

  Even if comprised in this way, by tilting the top surfaces 241a and 251a of the first manifold 241 and the second manifold 251 in the longitudinal direction, bubbles can be collected on one end side by buoyancy.

  Therefore, similarly to the third embodiment, even if the first bubble discharge path and the second bubble discharge path are one path, the bubbles can be reliably discharged and the configuration is simplified.

  In addition, the bubbles that have moved from the first manifold 241 to the second manifold 251 through the first bubble discharge path rise as they are to the portion where the second bubble discharge path is connected by buoyancy. Thereby, since the bubbles do not move in the longitudinal direction in the second manifold 251, it is possible to reduce the bubbles from melting into the second manifold 251 while reducing the possibility that the bubbles are supplied to the head.

  Next, the part (liquid circulation apparatus) concerning the liquid supply circulation in the fifth embodiment of the present invention will be described with reference to FIG. FIG. 10 is a block diagram for explaining the same.

  In the present embodiment, the top surface 241a of the first manifold 241 is inclined so as to increase from both ends in the longitudinal direction toward the center. The first bubble discharge path 301 is connected to a high portion of the top surface 241a of the first manifold 241.

Similarly, the top surface 251a of the first manifold 251 is inclined so as to increase from both ends in the longitudinal direction toward the center. The second bubble discharge path 302 is connected to a high portion of the top surface 251a of the second manifold 251.
ing.

  Even with this configuration, air bubbles can be collected by buoyancy at the central portions of the top surfaces 241a and 251a of the first manifold 241 and the second manifold 251.

  Therefore, similarly to the third embodiment, even if the first bubble discharge path and the second bubble discharge path are one path, the bubbles can be reliably discharged and the configuration is simplified. In addition, since the bubbles that have moved from the first manifold to the second manifold through the first bubble discharge path rise as they are to the portion where the second bubble discharge path is connected by buoyancy, they do not move in the longitudinal direction in the second manifold. The possibility of being supplied to the head can be reduced.

  In addition, since the bubble discharge path is provided near the center of each manifold, minute pressure changes due to the opening and closing of the valves provided in the bubble discharge path are targeted from the vicinity of the center toward the upstream side and the downstream side. It is transmitted to. As a result, it is possible to reduce the printing unevenness caused by the pressure change, as compared with the case where the bubble discharge path is provided near the end of the manifold.

  In the present application, the “liquid” to be ejected is not particularly limited as long as it has a viscosity and surface tension that can be ejected from the head, but the viscosity is 30 mPa · s or less at normal temperature, normal pressure, or by heating and cooling. It is preferable that More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional materials such as polymerizable compounds, resins, and surfactants, and biocompatible materials such as DNA, amino acids, proteins, and calcium. , Edible materials such as natural pigments, solutions, suspensions, emulsions, and the like. These include, for example, inkjet inks, surface treatment liquids, components of electronic devices and light emitting devices, and formation of electronic circuit resist patterns. It can be used in applications such as liquids for use, three-dimensional modeling material liquids, and the like.

  “Liquid ejection head” includes a piezoelectric actuator (laminated piezoelectric element and thin film piezoelectric element), a thermal actuator using an electrothermal conversion element such as a heating resistor as an energy generation source for ejecting liquid, a diaphragm and a counter electrode Those using an electrostatic actuator made of or the like are included.

  The “apparatus for ejecting liquid” includes an apparatus for ejecting liquid by driving a liquid ejection head. The apparatus for ejecting a liquid includes not only an apparatus capable of ejecting a liquid to an object to which the liquid can adhere, but also an apparatus for ejecting the liquid into the air or liquid.

  This “apparatus for discharging liquid” may include means for feeding, transporting, and discharging a liquid to which liquid can adhere, as well as a pre-processing apparatus and a post-processing apparatus.

  For example, as a “liquid ejecting device”, an image forming device that forms an image on paper by ejecting ink, a powder is formed in layers to form a three-dimensional model (three-dimensional model) There is a three-dimensional modeling apparatus (three-dimensional modeling apparatus) that discharges a modeling liquid onto the powder layer.

  Further, the “apparatus for ejecting liquid” is not limited to an apparatus in which significant images such as characters and figures are visualized by the ejected liquid. For example, what forms a pattern etc. which does not have a meaning in itself, and what forms a three-dimensional image are also included.

  The above-mentioned “applicable liquid” means that the liquid can be attached at least temporarily and adheres and adheres, or adheres and penetrates. Specific examples include recording media such as paper, recording paper, recording paper, film, and cloth, electronic parts such as electronic substrates and piezoelectric elements, powder layers (powder layers), organ models, and test cells. Yes, unless specifically limited, includes everything that the liquid adheres to.

  The material of the above-mentioned “material to which liquid can adhere” is not limited as long as liquid such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics can be adhered even temporarily.

  In addition, the “device for ejecting liquid” includes a device in which the liquid ejection head and the device to which the liquid can adhere move relatively, but is not limited thereto. Specific examples include a serial type apparatus that moves the liquid discharge head, a line type apparatus that does not move the liquid discharge head, and the like.

  In addition, as the “device for ejecting liquid”, other than the above, a treatment liquid coating apparatus that ejects a treatment liquid onto a sheet in order to apply the treatment liquid to the surface of the sheet for the purpose of modifying the surface of the sheet, There is an injection granulation apparatus that granulates raw material fine particles by spraying a composition liquid in which raw materials are dispersed in a solution through a nozzle.

  Note that the terms “image formation”, “recording”, “printing”, “printing”, “printing”, “modeling” and the like in the terms of the present application are all synonymous.

5 Printing Means 10 Continuum 50 Head Unit 100 Liquid Discharge Head (Head)
200 Liquid supply device 201 Main tank (liquid storage means)
202 1st liquid feeding pump (liquid feeding means)
203 2nd liquid feed pump 211 1st subtank 221 2nd subtank 241 1st manifold 252 2nd manifold 301, 301A, 301B 1st bubble discharge path 302, 302A, 302B 2nd bubble discharge path 303 Common bubble discharge path 311, 311A 311B Solenoid valve 312, 312A, 312B Solenoid valve 1000 Printing device (device for discharging liquid)

Claims (14)

A circulation path through which the liquid circulates via a liquid discharge head;
In the circulation path, an upstream manifold that leads to the supply ports of a plurality of liquid ejection heads,
A downstream manifold that leads to a discharge port side of the plurality of liquid discharge heads;
A discharge side flow path for discharging the liquid in the downstream side manifold,
A liquid circulation apparatus, wherein a bubble discharge path for discharging bubbles in the downstream manifold is provided separately from the discharge flow path. 2. The liquid circulation device according to claim 1, wherein an outlet of the bubble discharge path is disposed in a sub-tank that communicates with the downstream manifold. 3. The liquid circulation device according to claim 1, further comprising two bubble discharge paths that respectively communicate with both ends of the downstream side manifold in the longitudinal direction. In the longitudinal direction, the downstream manifold is inclined so that the top surface becomes higher from one end side toward the other end side, or the top surface becomes higher from both end sides toward the center portion. The liquid circulation device according to any one of claims 1 to 3, wherein the bubble discharge path communicates with a portion where the top surface is inclined. A circulation path through which the liquid circulates through the liquid discharge head;
In the circulation path, an upstream manifold that leads to the supply ports of a plurality of liquid ejection heads,
A downstream manifold that leads to a discharge port side of the plurality of liquid discharge heads,
A first bubble discharge path for discharging bubbles from the upstream manifold to the downstream manifold;
A second bubble discharge path for discharging bubbles from the downstream manifold to the outside of the downstream manifold,
The liquid circulation device according to claim 1, wherein the first bubble discharge path and the second bubble discharge path are different paths from the circulation path. The liquid circulation apparatus according to claim 5, wherein the downstream manifold is disposed at a position higher than the upstream manifold. 7. The liquid circulation device according to claim 5, wherein an outlet of the second bubble discharge path is disposed in a sub-tank that communicates with the downstream manifold. It has two first bubble discharge paths that respectively communicate with both ends in the longitudinal direction of the upstream manifold, and two second bubble discharge paths that respectively communicate with both ends in the longitudinal direction of the downstream manifold. The liquid circulation device according to claim 5. A first on-off valve for opening and closing the first bubble discharge path;
A second on-off valve that opens and closes the second bubble discharge path,
When discharging bubbles,
The first on-off valve of the first bubble discharge path that communicates with one longitudinal end of the upstream manifold, and the second on-off valve of the second bubble discharge path that communicates with the other longitudinal end of the upstream manifold The liquid circulation device according to claim 8, wherein the liquid circulation device is opened. 10. The liquid circulation apparatus according to claim 8, wherein the liquid inflow side of the upstream manifold and the liquid discharge side of the downstream manifold are arranged on the same side in the longitudinal direction. One end of the first bubble discharge path is connected to the end opposite to the liquid inflow side to the upstream manifold,
The other end of the first bubble discharge path leads to an end of the downstream manifold opposite to the liquid discharge side,
The liquid circulation device according to claim 5, wherein the second bubble discharge path communicates with an end of the downstream manifold on the liquid discharge side. In the longitudinal direction, the upstream manifold is inclined so that the top surface becomes higher from one end side toward the other end side, or the top surface becomes higher from both end sides toward the center portion. The liquid circulation device according to any one of claims 5 to 7, wherein the first bubble discharge path communicates with a portion where the top surface is inclined. In the longitudinal direction, the downstream manifold is inclined so that the top surface becomes higher from one end side toward the other end side, or the top surface becomes higher from both end sides toward the center portion. The liquid circulation device according to any one of claims 5 to 7 and 12, wherein the second bubble discharge path communicates with a portion inclined so as to have a higher top surface. A plurality of liquid discharge heads for discharging liquid;
An apparatus for ejecting liquid, comprising: the liquid circulation apparatus according to claim 1.

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