JP2019130668A - Liquid circulation system, and liquid discharging device - Google Patents

Abstract

To perform filling of a liquid into a circulation path while suppressing contamination of air bubbles.SOLUTION: A third sub-tank 290 constitutes a confluent part at which a circulation path 280 and a liquid path 289, which is a replenishment path, are confluent, and comprises a waste liquid path 402 which is branched from a liquid path 283 on an upstream side with respect to the third sub-tank 290, and a drain valve 401 which switches connection and disconnection between the waste liquid path 402 and the liquid path 283 which constitutes the circulation path 280. When performing liquid filling, a liquid is fed by a first liquid feeding pump 202 in the state that downstream of a junction a of the liquid path 283 and the waste liquid path 401 are communicated with each other thereby filling the liquid to a connection with the waste liquid path 401, and the waste liquid path 401 and the third sub-tank 290 are communicated with each other, thereby performing filling of the liquid between the waste liquid path 401 and the third sub-tank 290.SELECTED DRAWING: Figure 5

Description

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

  As a liquid discharge head (hereinafter also simply referred to as “head”), the liquid supply head has a supply flow path to the individual liquid chamber that communicates with the nozzle and a recovery flow path that communicates with the individual liquid chamber. There is a flow-through type head (circulation type head) provided with a mouth and a liquid recovery port leading to a recovery flow path.

  Conventionally, as a liquid circulation device for a liquid ejection unit such as a liquid ejection head, a supply channel for supplying liquid to the liquid ejection unit, a recovery channel for recovering liquid from the liquid ejection unit, and the pressure of the liquid in the supply channel First pressure adjusting means for adjusting, second pressure adjusting means for adjusting the pressure of the liquid in the recovery flow path, and opening / closing provided in at least one of the supply flow path and the recovery flow path to open and close the flow path The valve, the first pressure adjusting means, the second pressure adjusting means, and the on-off valve are controlled, and the liquid is circulated between the supply-side liquid pressure and the recovery-side liquid pressure with respect to the nozzle while holding the liquid at the nozzle. There is one that causes a time difference pressure to circulate a liquid (Patent Document 1).

Japanese Patent No. 5215376

  By the way, for example, when initial filling is performed on the circulation path of the liquid circulation device, there is a problem that the filling must be performed while suppressing the mixing of bubbles.

  The present invention has been made in view of the above problems, and an object of the present invention is to prevent liquid bubbles from being mixed and fill the circulation path with liquid.

In order to solve the above problems, a liquid circulation device according to the present invention is
A circulation path through which liquid supplied to the liquid discharge head and recovered from the liquid discharge head circulates;
A supply path for supplying the liquid to the circulation path;
A drainage path that branches from the circulation path on the upstream side of the joining portion where the circulation path and the replenishment path meet;
Switching means for switching communication and blocking between the drainage path and the circulation path is provided.

  According to the present invention, it is possible to fill the circulation path with liquid while suppressing the mixing of bubbles.

It is a schematic explanatory drawing of an example of the printing apparatus which is an 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 explanatory drawing with which it uses for description of the liquid circulation apparatus in 1st Embodiment of this invention. It is a block diagram with which it uses for description of the outline | summary of the control part in the apparatus. It is explanatory drawing with which it uses for description of the liquid filling operation | movement in the embodiment. It is explanatory drawing with which it uses for description of the liquid filling operation | movement in the embodiment. It is a perspective explanatory drawing with which it uses for detailed description of a drainage path and a drainage tank. It is explanatory drawing of the part of the drain valve (switching means) and 3rd sub tank in 2nd Embodiment of this invention. It is explanatory drawing of the suction mechanism part with which it uses for description of the liquid filling to a head.

  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. 10 includes a printing unit 5 that performs printing to form an image by ejecting a liquid to the unit 10, a drying unit 7 that dries the continuous body 10, and a carry-out unit 9 that carries the continuous body 10 out.

  The continuous body 10 is fed 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 carry-out means 9, and the take-up roller 91 of the carry-out 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 100, 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 recovery side common liquid chamber 150. The supply-side common liquid chamber 110 communicates with a supply port (supply port) 171, and the recovery-side common liquid chamber 150 communicates with a recovery port (collection port) 172.

  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 recovery side common liquid chamber 150 that communicates with the recovery 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.

  In addition, a recovery channel 151 is formed in the channel plate 102 along the surface direction of the channel plate 102 that communicates with each individual liquid chamber 106 via the nozzle communication path 105. The recovery channel 151 communicates with the recovery 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 flows into the recovery side common liquid chamber 150 from the recovery flow path 151, and then returns to the supply side common liquid chamber 110 from the recovery side common liquid chamber 150 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, the part which concerns on the liquid circulation apparatus in 1st Embodiment of this invention is demonstrated with reference to FIG. FIG. 5 is a block diagram for explaining the same.

  The liquid circulation device 200 circulates the liquid with respect to a plurality of circulatorable heads 100 arranged in a line in the width direction of the continuum 10.

  The liquid circulation device 200 includes a main tank 201 that is a liquid tank as a liquid storage unit that stores the liquid 600 discharged from the head 100. Further, the first sub tank 220 as a pressurizing sub tank, the second sub tank 210 as a depressurizing tank, the third sub tank 290 as an intermediate tank, the first liquid feeding pump 202 as a first liquid feeding means, and the second A second liquid feeding pump 203 and a third liquid feeding pump 209 are provided as liquid feeding means.

  Further, the first manifold 230 and the second manifold 240 through which the plurality of heads 100 communicate, the first head tank 300a and the second head tank 300b for each head 100, and deaeration means for removing dissolved gas in the liquid. A deaeration device 260 is provided. The first head tank 300a and the second head tank 300b are referred to as a head tank (or a buffer tank) 300 unless they are distinguished from each other.

  Here, a third sub-tank 290 is disposed between the first sub-tank 220 and the second sub-tank 210, and the third sub-tank 209 is supplied from the main tank 201 via a liquid path 289 that is a replenishment path including the filter 205. 3 Sub-tank 290 is fed (supplemented).

  The third sub-tank 290 includes a liquid level detection unit 291 and an electromagnetic valve 292 that constitutes an atmosphere release mechanism that opens the interior to the atmosphere.

  The third sub tank 290 and the second sub tank 210 are connected through a liquid path 283, and the second liquid feed pump 203 is provided in the liquid path 283. Further, the third sub tank 290 and the second sub tank 210 are connected through the backflow liquid path 285, and the backflow liquid path 285 is provided with an electromagnetic valve 287.

  The second sub-tank 210 has a gas chamber 210a and has a configuration in which liquid and gas coexist. The second sub tank 210 is provided with a liquid level detecting means 211 for detecting the liquid level and an electromagnetic valve 212 serving as an atmospheric release mechanism for releasing the interior to the atmosphere.

  The third sub tank 290 and the first sub tank 220 are connected through a liquid path 284, and the first liquid feed pump 202 is provided in the liquid path 284. Further, the third sub tank 290 and the first sub tank 220 are connected through a backflow liquid path 286, and an electromagnetic valve 288 is provided in the backflow liquid path 286.

  The first sub-tank 220 has a gas chamber 220a and has a configuration in which liquid and gas coexist. The first sub tank 220 is provided with a liquid level detecting means 221 for detecting the liquid level, and an electromagnetic valve 222 serving as an air release mechanism for opening the inside to the atmosphere.

  The first sub tank 220 is connected to the first manifold 230 through a liquid path 281 including a deaeration device 260 and a filter 261.

  The first manifold 230 communicates with the supply port 171 (supply port) side of the head 100 via a supply path 231. The supply path 231 is connected to the supply port 171 of the head 100 via the first head tank 300a.

  The supply path 231 is provided with an electromagnetic valve 232 that opens and closes a path upstream of the first head tank 300a. The electromagnetic valves 232 are provided according to the number of the heads 100 and can be individually controlled to be opened and closed. The first manifold 230 is provided with a pressure sensor 233.

  The second sub tank 210 is connected to the second manifold 240 via the liquid path 282.

  The second manifold 240 communicates with the recovery port 181 (recovery port) side of the head 100 via a recovery path 241. The collection path 241 is connected to the collection port 181 of the head 100 via the second head tank 300b.

  The recovery path 241 is provided with an electromagnetic valve 242 that opens and closes a path downstream of the second head tank 300b. The electromagnetic valves 242 are provided according to the number of the heads 100 and can be individually controlled to be opened and closed. The second manifold 240 is provided with a pressure sensor 243.

  Further, a bypass path 270 that passes through the first manifold 230 and the second manifold 240 is provided. In the bypass path 270, an electromagnetic valve 271 as bypass opening / closing means is provided on the first manifold 230 side, and in the liquid path 282 between the second manifold 240 and the second sub tank 210, electromagnetic valve 272 as recovery side opening / closing means is provided. Is provided.

  Here, from the third sub tank 290, the liquid passage 284, the first sub tank 220, the liquid passage 281, the deaeration device 260, the first manifold 230, the head 100, the second manifold 240, and the second sub tank 210 are passed through the third sub tank 290. A circulation path 280 is configured by the path returning to the line.

  In addition, the solenoid valve 232, 242, 271 blocks between the head 100 and the circulation path 280, and the bypass path 270 forms a part of the circulation path 280, the bypass path 270, the circulation path 280, Is configured so that the head 100 switches the second path that forms part of the circulation path 280.

  That is, by closing the electromagnetic valves 232 and 242 and opening the electromagnetic valve 271, the bypass path 270 becomes a part of the circulation path 280 and the first path in which the head 100 does not become a part of the circulation path 280 is configured.

  Further, by opening the electromagnetic valves 232 and 242 and closing the electromagnetic valve 271, the head 100 becomes a part of the circulation path 280, and the second path in which the bypass path 270 does not become a part of the circulation path 280 is configured.

  The first sub-tank 220 and the second sub-tank 210, the first liquid feeding pump 202, and the second liquid feeding pump 203 constitute means for generating a pressure for circulating the liquid through the circulation path 280.

  Next, liquid supply and circulation will be described.

  The liquid supply (replenishment) from the main tank 201 to the third sub tank 290 is carried out from the main tank 201 by using the third liquid supply pump 209 when the liquid level detection means 291 of the third sub tank 290 detects a shortage of liquid. The liquid is supplied to the third sub tank 290 through the liquid path 289 until the liquid level is filled by the liquid level detecting means 291.

  Liquid feeding from the third sub tank 290 to the first sub tank 220 uses the first liquid feeding pump 202 to supply liquid from the third sub tank 290 to the first sub tank 220 via the liquid path 284.

  Liquid feeding from the second sub tank 210 to the third sub tank 290 uses the second liquid feeding pump 203 to supply liquid from the second sub tank 210 to the third sub tank 290 via the liquid path 283.

  Liquid feeding from the first sub tank 220 to the head 100 and from the head 100 to the second sub tank 210 is performed as follows.

  In other words, the liquid is supplied to the first sub tank 220 by the first liquid feed pump 202 until the target pressure (for example, the pressure to be increased) is reached by the pressure sensor 233 of the first manifold 230. At the same time, the liquid is fed to the third sub-tank 290 by the second liquid feed pump 203 until the target pressure (for example, a negative pressure) is reached by the pressure sensor 243 of the second manifold 240.

  Thereby, a differential pressure is generated between the first sub tank 220 and the second sub tank 210.

  In response to this differential pressure, the filter 261, the deaeration device 260, the first manifold 230, the plurality of supply paths 231, the plurality of first head tanks 300a, and the plurality of heads 100 are passed from the first sub tank 220 through the liquid path 281. The liquid can be circulated to the second sub tank 210 via the plurality of recovery paths 241, the plurality of second head tanks 300 b, the second manifold 240, and the liquid path 282. At this time, the solenoid valves 232 and 242 are open, and the solenoid valve 271 is closed.

  On the other hand, when the electromagnetic valves 232 and 242 are closed and the electromagnetic valve 271 is opened, when the first liquid pump 202 and the second liquid pump 203 are driven to generate a differential pressure, according to the differential pressure, Circulation of liquid from the first sub-tank 220 to the second sub-tank 210 through the filter 261, the deaeration device 260, the first manifold 230, the bypass passage 270, the second manifold 240, and the liquid passage 282 via the liquid passage 281. It becomes possible.

  In addition, the liquid level detection means 221, 211, 291 provided in each sub tank 220, 210, 290 is not particularly limited. For example, detection of the presence or absence of liquid by a float type or at least two or more electrode pins. A method of detecting the presence or absence of liquid according to the output of the resistor detected by using the liquid, a liquid level detection method using a laser, or the like can be used.

  In addition, the sub tanks 210, 220, and 290 are provided with solenoid valves 212, 222, and 292, respectively, as air release mechanisms. By controlling these, the sub tanks 210, 220, and 290 are communicated with the atmosphere. be able to.

  Next, the roles of the gas chamber 220a of the first sub tank 220 and the gas chamber 210a of the second sub tank 210 will be described. In the gas chamber 220a and the gas chamber 210a, the liquid level is in contact with air, for example.

  Here, when a pressurized state of air is generated in the first sub-tank 220 and a reduced pressure state of air is generated in the second sub-tank 210, the pressure can be stored because the gas is compressible. The air in this case is considered to be the same as the capacitor component when expressed by an equivalent electric circuit, and can also be expressed as compliance (elastic component).

  When the first liquid feed pump 202 and the second liquid feed pump 203 communicating with the first sub tank 220 and the third sub tank 290 and the second sub tank 210 and the third sub tank 290 are driven, a pressure change (pulsation) occurs. . When this pressure change is transmitted through the liquid path and transmitted to the nozzle meniscus of the head 100, it leads to overflow of liquid and entrainment of bubbles.

  Therefore, compliance (elastic component) is required to suppress this. In general, since air has a compressible property, it becomes a compliance component. By having the gas chambers 220a and 210a, a pressure change (pulsation) can be suppressed.

  Next, a configuration related to bubble discharge at the time of liquid filling in the liquid circulation device 200 will be described.

  In the present embodiment, the third sub-tank 290 serves as a junction where the circulation path 280 and the liquid path 289 that is a replenishment path merge. The drainage path 402 is branched from the liquid path 283 on the upstream side of the third sub tank 290, and is a switching means for switching connection and disconnection between the drainage path 402 and the liquid path 283 constituting the circulation path 280. And a drain valve 401.

  The drain valve 401 is a three-way valve having three outlets and selectively switching three paths. The drain valve 401 may be a manually switching type constituted by an electromagnetic valve that is electrically driven.

  One outlet / inlet of the drain valve 401 is connected to the downstream side of the second liquid feeding pump 203 in the liquid path 283, here, downstream of the connection point a between the liquid path 283 and the downstream side of the backflow liquid path 285. Further, the other inlet / outlet of the drain valve 401 is connected to the upstream side connected to the liquid path 283 of the third sub tank 290. Further, the remaining one entrance of the drain valve 401 is connected to the drainage path 402. The end of the drainage path 402 is connected to the drainage tank 403.

  By switching the drain valve 401, the downstream of the connection point a downstream of the backflow liquid path 285 and the upstream of the third sub tank 290 communicate with each other, the first path where the liquid path 283 communicates, and the downstream connection of the backflow liquid path 285 The second path where the drainage path 402 communicates with the downstream of the point a and the third path where the upstream side of the third sub tank 290 communicates with the drainage path 402 can be selectively switched. In the first path, the internal flow path of the drain valve 401 also constitutes a part of the circulation path 280.

  The drainage tank 403 communicating with the drainage path 402 includes an electromagnetic valve 404 and a pressure sensor 406 that enable communication with the atmosphere. The drainage tank 403 preferably has a capacity that exceeds the volume of all the paths through which the liquid circulates.

  Here, the drainage path 402 is piped upward from the drain valve 401, which is a connection portion with the liquid path 283 constituting the circulation path 280, in the direction opposite to the gravity direction in order to raise bubbles in the path by buoyancy. ing.

  Further, the drainage tank 403 is preferably disposed above the drainage path 402, and the drainage path 403 is preferably connected at the bottom of the drainage tank 403.

  In the present embodiment, the head assembly 400 including the head 100, the first head tank 300 a, the second head tank 300 b, and the coupling 405 is attached to the supply path 231 and the recovery path 241 in a replaceable manner. Is configured.

  The head assembly 400 can be detachably attached to the supply path 231 and the recovery path 241 by a coupling 405.

  The head 100 can be in an individual state by being disconnected at the coupling 405. Therefore, the filling liquid can be filled in advance in the state of the head assembly 400. Therefore, in the present embodiment, in the initial state, the head assembly 400 is prefilled with a filling liquid with good wettability or a predetermined liquid.

  Next, an overview of the control unit of the printing apparatus 1000 will be described with reference to FIG. FIG. 6 is a block diagram of the control unit.

  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 (NVRAM) for holding data even when the power of the apparatus is shut 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, and is connected to the printer driver 590 via the host I / F 506. Send and receive data with.

  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 electromagnetic valves 232, 242, and 271 of the electromagnetic valve group 550 and the electromagnetic valves 212, 222, 292, 287, and 288. The control unit 500 includes a supply system control unit 511 that drives and controls the third liquid feeding pump 209.

  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 513. The I / O unit 513 can process various sensor information, and obtains detection results from the pressure sensors 233 and 243 and information from various sensor groups 515. Then, information necessary for controlling the apparatus is set up and used for control by the print control unit 508, the electromagnetic valve control unit 510, 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, the liquid filling operation in the present embodiment will be described with reference to FIGS. 7 and 8 are explanatory views for explaining the operation.

  As described above, the liquid can be filled in advance in the state of the head assembly 400 including the head 100. In the present embodiment, the head assembly 400 is prefilled with a liquid having a good wettability (filling liquid).

  First, all the solenoid valves 232 and 242 in the supply path 231 and the recovery path 241 of each head assembly 400 are closed. Further, the electromagnetic valve 271 in the bypass path 270 is opened.

  As a result, the liquid inflow into each head assembly 400 is stopped, and the circulation path 280 that does not pass through the head assembly 400 can be secured by opening the bypass path 270. Note that each liquid path (piping path) and the first sub tank 220, the second sub tank 210, and the third sub tank 290 constituting the circulation path 280 at this time are empty.

  The main tank 201 stores a liquid 600 that fills the circulation path 280. The electromagnetic valve 292 in the third sub tank 290 is opened to communicate with the atmosphere, the third liquid feed pump 209 is driven, and the liquid 600 is filled in the third sub tank 290.

  Then, the liquid level detecting means 291 of the third sub tank 290 stops the driving of the third liquid feed pump 209 when the liquid level height reaches a predetermined position. Thereafter, the third liquid feed pump 209 is driven according to the detection result of the liquid level of the liquid level detection means 291 and the liquid supply (replenishment) operation to the third sub tank 290 is repeated.

  Next, the electromagnetic valve 222 of the first sub tank 220 is opened to communicate with the atmosphere. In order to fill the back flow liquid path 286 with the liquid 600, the electromagnetic valve 292 of the third sub tank 290 is closed. As a result, the third sub tank 290 is hermetically sealed, and the third liquid feeding pump 209 is driven in this state. By feeding a predetermined time or a predetermined amount, the backflow liquid path 286 is filled. Thereafter, the electromagnetic valve 288 is closed and the electromagnetic valve 292 is opened.

  Next, in a state where the electromagnetic valve 222 of the first sub tank 220 is open and communicates with the atmosphere, the first liquid pump 202 is driven, and liquid is supplied to the first sub tank 220 until the liquid level detection means 221 detects it. After filling, the first liquid pump 202 is stopped. After the first liquid pump 202 is stopped, the electromagnetic valve 222 is closed, and the first sub-tank 220 is filled with a predetermined amount of liquid and sealed.

  In this state, the drain valve 401 communicates with the connection point a downstream of the second liquid pump 203 and the drainage path 402, and the liquid path 283 and the third sub tank 290 are blocked ("x" in FIG. 7). Is switched to the second state.

  Here, by driving the first liquid pump 202 and the second liquid pump 203, the gas chamber 220a of the first subtank 220 has a positive pressure, and the gas chamber 210a in the second subtank 210 is negative. The pressure rises and the liquid flows through the path with the pressure difference.

  The air in the circulation path 280 including the bypass path 270 is guided to the drainage tank 403 by the second liquid feed pump 203, and at the same time, the liquid is pushed out by the first liquid feed pump 202 and flows in the circulation path 280. It will be.

  Note that the setting of the pressure difference can be adjusted by the discharge of air and the movement state of the liquid. How to fill by adjusting the pump driving force of each of the first liquid pump 202 and the second liquid pump 203. Can be changed.

  In this way, the air in the circulation path 280 is discharged and the liquid enters the waste liquid dunk 403 or the second liquid feed pump 203 is stopped in a state where the liquid discharge path 402 is filled with the liquid. Then, the electromagnetic valve 212 of the second sub tank 210 is opened to communicate with the atmosphere. Since the first liquid feed pump 202 is being driven, the liquid is filled in the second sub tank 210. When the liquid level detecting means 211 of the second sub tank 210 detects the liquid level, the first liquid pump 202 is stopped, so that the second sub tank 210 is filled with a predetermined amount of liquid. .

  Thereafter, the electromagnetic valve 212 of the second sub tank 210 is closed, and the second sub tank 210 is sealed. Then, the electromagnetic valve 287 of the backflow liquid path 285 is opened, and the first liquid feed pump 202 is driven again, so that the backflow liquid path 285 is filled with liquid. After filling, the electromagnetic valve 287 is closed.

  The second liquid feed pump 203 preferably has a check valve function that prevents backflow when the pump is stopped. For example, it is preferable to use a diaphragm pump for feeding liquid by opening and closing a valve, a tubing pump for feeding liquid by handling a liquid feeding tube, and the like.

  Next, filling of the path 283a between the drain valve 401 and the third sub tank 290 will be described.

  Through the above-described operation, the third sub tank 290, the liquid path 284, the backflow liquid path 286, the first sub tank 220, the liquid path 281, the filter 261, the deaeration device 260, the first manifold 230, the bypass path 270, the second manifold 240, The liquid 600 is filled up to the liquid path 282, the second sub tank 210, the backflow liquid path 285, the downstream of the connection point a downstream of the backflow liquid path 285, and the drainage path 402.

  Here, if the drain path 402 is cut off from the circulation path 280 to form a path that connects the downstream of the connection point a of the liquid path 283 and the upstream of the third sub tank 290, the drain valve 401 to the third sub tank 290 The route is opened with air remaining in the section.

  In this case, air flows into the third sub tank 290 and bubbles are generated in the third sub tank 290, which may cause malfunction of the liquid level detection means 291, leakage of bubbles from the electromagnetic valve 292, and the like. is there.

  Therefore, in order to discharge air in the section (path 283a) between the drain valve 401 and the third sub tank 290, first, the electromagnetic valve 292 of the third sub tank 290 is closed, and the third sub tank 290 is sealed. .

  After that, as shown in FIG. 8, the path is switched by the drain valve 401, so that the drain tank 403 communicates with the upstream side of the third sub tank 290 through the drain path 402.

  By driving the third liquid feeding pump 209, the liquid in the third sub tank 290 moves toward the drainage tank 403, and the upstream side of the third sub tank 290 and the liquid path 283 of the drainage path 402 are moved. The path of the section to the connecting portion is filled with the liquid.

  Then, the drain valve 401 is opened downstream of the connection point a downstream of the backflow liquid path 285 and upstream of the third sub tank 290, and the drainage path 402 is switched to the state disconnected from the liquid path 283.

  As a result, the circulation path 280 other than the head assembly 400 is filled with the liquid.

  In this way, liquid filling can be performed in a short time without leaving bubbles in the circulation path 280 and without causing bubbles to move in the recirculation direction.

  Thereafter, the filling of the liquid into the head assembly 400 is completed by discharging the liquid from the nozzle by means such as a suction mechanism and replacing the filling liquid previously filled in the head assembly 400 with the liquid.

  In the above description of the filling operation, the route other than the head assembly 400 is described as being empty. However, similarly to the head assembly 400, a filling liquid or the like may be filled in advance. In this case, the liquid to be filled is fed while discharging the liquid filled in advance to the drain tank 403, thereby replacing the liquid filled in the piping path other than the head assembly 400 with the liquid. In this case, the filling liquid is discharged to the drainage tank 403 and does not return to the third sub tank 290, so that the replacement time can be greatly shortened.

  Next, details of the drainage path and drainage tank will be described with reference to FIG. FIG. 9 is a perspective view for explaining the same.

  The drainage tank 403 and the drainage path 402 are disposed so as to face upward with respect to the liquid flow in the liquid path 283 constituting the circulation path 280.

  As a result, the air or the liquid accompanied by the bubbles 407 sent from the liquid path 283 to the drainage path 402 is discharged to the drainage tank 403, the bubbles 407 rise by buoyancy, and the air layer accumulates upward. The bubbles 407 that are lighter than the liquid always go to the head of the liquid flow in the drainage path 402 and are separated into gas and liquid in the drainage tank 403.

  Thereby, the bubbles 407 in the circulation path 280 can be collected through the drainage path 402.

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 10 is an explanatory diagram of the drain valve (switching means) and the third sub tank in the same embodiment.

  By shortening the path between the drain valve 401 and the third sub tank 290 as much as possible, the generation of bubbles 407 can be suppressed and the filling operation can be further shortened.

  The drain valve 401 has three entrances that are opened and closed by valve bodies 408, 409, and 410. And the entrance / exit part which has the valve body 409 of the drain valve 401 is directly connected with the side wall 290a so that it may become a part of the side wall 290a of the 3rd sub tank 290.

  The other two-way valve body 408 has an inlet / outlet connected to the liquid path 283, and the inlet / outlet having the valve body 410 is connected to the drainage path 402.

  The drain valve 401 has a flow path that is divided into three directions. By combining the operations of the valve bodies 408, 409, and 410, a flow path in the three directions can be formed.

  For example, when the downstream of the connection point a downstream of the backflow liquid path 285 and the upstream of the third sub tank 290 are opened, the valve bodies 408 and 409 are opened, and the valve body 410 is closed. When opening the drainage path 402 downstream of the connection point a downstream of the backflow liquid path 285, the valve body 408 and the valve body 410 are opened, and the valve body 409 is closed. When the upstream side of the third sub tank 290 and the drainage tank 403 are opened, the valve body 409 and the valve body 410 are opened, and the valve body 408 is closed.

  Next, liquid filling into the head 100 will be described with reference to FIG. FIG. 11 is an explanatory view of a suction mechanism unit provided for the description.

  The suction mechanism unit 700 includes a cap 701 that caps the nozzle surface 101a of the head 100, a suction pump 703 that sucks the inside of the cap 701 through a waste liquid path 702, and the like.

  Then, after the filling other than the head 100 is completed, the suction mechanism 700 sucks and discharges the cleaning liquid from the nozzle 104, whereby the liquid is replaced with the liquid and the head 100 is also filled with the liquid k.

  In addition to the suction, the head 100 can be filled with a liquid under pressure and discharged from the nozzle.

  For example, the electromagnetic valve 272 downstream of the second manifold 240 is closed, and the electromagnetic valve 271 of the bypass path 270 is opened. By driving the first liquid feed pump 202 in this state, positive pressure is applied to both the first manifold 230 and the second manifold 240, and the liquid in the supply path 231 and the recovery path 241 connected to the plurality of heads 100. Both flow toward the head 100 and can be discharged from the nozzle of each head 100.

  As another method, as the second liquid feeding pump 203, a reversible pump capable of feeding in both directions of the circulation direction and the direction opposite to the circulation direction is used.

  When the second liquid feed pump 203 is driven in reverse, the liquid flows through the second manifold 240 in the direction opposite to the circulation, and positive pressure is applied to the recovery path 241. At the same time, by driving the first liquid feed pump 202, a positive pressure is applied to the supply path 231, and the liquid can be discharged from the nozzle by the positive pressure from both sides.

  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 circulation device 201 Main tank (liquid storage means)
202 1st liquid feed pump 203 2nd liquid feed pump 209 3rd liquid feed pump 210 2nd subtank 220 1st subtank 230 1st manifold 240 2nd manifold 260 Deaeration device 270 Bypass path 280 Circulation path 290 3rd subtank 401 Drain Valve (switching means)
402 Drainage path 403 Drainage tank 1000 Printing device (device for discharging liquid)

Claims (9)

A circulation path through which liquid supplied to the liquid discharge head and recovered from the liquid discharge head circulates;
A supply path for supplying the liquid to the circulation path;
A drainage path that branches from the circulation path on the upstream side of the joining portion where the circulation path and the replenishment path meet;
A liquid circulation device comprising switching means for switching communication and blocking between the drainage path and the circulation path. The circulation path includes
A first sub tank that communicates with a supply port of the liquid ejection head;
A second sub-tank leading to a recovery port of the liquid discharge head;
A third sub-tank disposed between the first sub-tank and the second sub-tank and supplied with the liquid through the replenishment path;
2. The liquid circulation device according to claim 1, wherein the drainage path branches from between the second sub tank and the third sub tank. The switching means is
A first state that blocks the drainage path and the circulation path;
A second state in which the second subtank side and the drainage path communicate with each other, and the drainage path and the third subtank side are blocked;
3. The third state according to claim 2, wherein the third sub-tank side and the drainage path are communicated with each other and can be switched to a third state in which the drainage path and the second subtank side are blocked. Liquid circulation device. 4. The liquid circulation device according to claim 2, wherein a connection portion connected to the third sub tank of the switching unit is connected in the liquid stored in the third sub tank. 5. 5. The liquid circulating apparatus according to claim 2, wherein the switching unit is integrated with a wall portion of the third sub tank. A bypass path connecting upstream and downstream of the liquid discharge head;
The liquid circulation device according to claim 1, further comprising bypass opening / closing means for opening and closing the bypass path. A collection-side opening / closing means for opening / closing between the liquid discharge head and the second sub-tank is provided;
The liquid circulation according to claim 6, wherein when the liquid discharge head is filled with the liquid, the recovery-side opening / closing means is closed, the bypass opening / closing means is opened, and the first liquid feeding means feeds the liquid. apparatus. The second liquid feeding means is a reversible liquid feeding means capable of feeding in both directions,
7. The liquid discharge head according to claim 1, wherein when the liquid discharge head is filled with the liquid, the liquid is supplied by the first liquid supply unit and is reversely transferred by the second liquid supply unit. Liquid circulation device. A plurality of liquid ejection heads;
An apparatus for ejecting liquid, comprising: the liquid circulation apparatus according to claim 1.

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