JP6996316B2 - Liquid circulation device, liquid discharge device - Google Patents

Description

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

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

Conventionally, as a liquid circulation device for a liquid discharge part such as a liquid discharge head, a supply flow path for supplying a liquid to the liquid discharge part, a recovery flow path for collecting the liquid from the liquid discharge part, and a liquid pressure in the supply flow path are used. A first pressure adjusting means for adjusting, a second pressure adjusting means for adjusting the pressure of the liquid in the recovery flow path, and opening and closing provided in at least one of the supply flow path and the recovery flow path to open and close the flow path. It controls the valve, the first pressure adjusting means, the second pressure adjusting means, and the on-off valve, and circulates between the pressure of the liquid on the supply side and the pressure of the liquid on the recovery side with respect to the nozzle while holding the liquid in the nozzle. There is a device that causes a staggered pressure to circulate a liquid (Patent Document 1).

Japanese Patent No. 5215376

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

The present invention has been made in view of the above problems, and an object of the present invention is to suppress the mixing of air bubbles so that the circulation path can be filled with liquid.

In order to solve the above problems, the liquid circulation device according to the present invention is
A circulation path in which the liquid supplied to the liquid discharge head and collected from the liquid discharge head circulates.
A supply route for supplying the liquid to the circulation route and a supply route.
A drainage path that branches off from the circulation path on the upstream side of the confluence where the circulation path and the replenishment path meet.
A switching means for switching communication and interruption between the drainage path and the circulation path is provided .
In the circulation path,
The first sub-tank leading to the supply port of the liquid discharge head and
The second sub-tank leading to the collection port of the liquid discharge head and
A third sub-tank, which is located between the first sub-tank and the second sub-tank and is supplied with the liquid through the replenishment path, comprises.
The drainage path branches from between the second sub-tank and the third sub-tank.
It was configured.

According to the present invention, it is possible to suppress the mixing of air bubbles and fill the circulation path with liquid.

It is a schematic explanatory drawing of an example of the printing apparatus which is the apparatus which ejects a liquid which concerns on this invention. It is a plane explanatory view of an example of the head unit of the same apparatus. It is an external perspective explanatory view of an example of a liquid discharge head. It is sectional drawing in the direction orthogonal to the nozzle arrangement direction (the liquid chamber longitudinal direction) of the head. It is explanatory drawing which provides the explanation of the liquid circulation apparatus in 1st Embodiment of this invention. It is a block diagram which provides the outline | description of the control part in this apparatus. It is explanatory drawing which provides the explanation of the liquid filling operation in the same embodiment. It is explanatory drawing which provides the explanation of the liquid filling operation in the same embodiment. It is a perspective explanatory drawing which provides the detailed explanation of a drainage path and a drainage tank. It is explanatory drawing of the part of the drain valve (switching means) and the 3rd sub-tank in the 2nd Embodiment of this invention. It is explanatory drawing of the suction mechanism part which provides the explanation of the liquid filling to a head.

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

The printing device 1000, which is a device for discharging this liquid, includes a carry-in means 1 for carrying in the continuous body 10, a guide transport means 3 for guiding and transporting the continuous body 10 carried in from the carry-in means 1 to the printing means 5, and a continuous body. It is provided with a printing means 5 for printing to form an image by ejecting a liquid to the ten, a drying means 7 for drying the continuum 10, a carrying-out means 9 for carrying out the continuum 10, and the like.

The continuum 10 is sent out from the original winding roller 11 of the carrying-in means 1, guided and conveyed by the rollers of the carrying-in means 1, the guiding and transporting means 3, the drying means 7, and the carrying-out means 9, and is guided and conveyed by the winding roller 91 of the carrying-out means 9. It is wound up at.

The continuum 10 is conveyed on the transfer guide member 59 in the printing means 5 facing the head unit 50 and the head unit 55, an image is formed by the liquid discharged from the head unit 50, and the continuous body 10 is discharged from the head unit 55. Post-treatment is performed with the treatment liquid to be treated.

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

Each head array 51 is a liquid discharging means, and discharges black K, cyan C, magenta M, and yellow Y liquids to the conveyed continuum 10, respectively. The types and numbers of colors are not limited to this.

The head array 51 is, for example, as shown in FIG. 2, in which liquid discharge heads (which are also simply referred to as “heads”) 100 are arranged in a staggered pattern on the base member 52, but the head array 51 is not limited to this. do not have.

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

The liquid discharge head 100 has a nozzle plate 101, a flow path plate 102, and a diaphragm member 103 as a wall surface member laminated and joined. Further, it includes a piezoelectric actuator 111 that displaces the 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. The portion composed of the flow path plate 102 and the diaphragm member 103 is referred to as a flow path member 140.

The nozzle plate 101 has a plurality of nozzles 104 for discharging a liquid.

The flow path plate 102 penetrates into the individual liquid chamber 106 that leads to the nozzle 104 via the nozzle communication passage 105, the supply-side fluid resistance portion 107 that leads to the individual liquid chamber 106, and the liquid introduction portion 108 that leads to the supply-side fluid resistance portion 107. It forms holes and grooves. The nozzle communication passage 105 is a flow path that connects to the nozzle 104 and the individual liquid chamber 106, respectively. Further, the liquid introduction portion 108 is connected to the common liquid chamber 110 on the supply side through the opening 109 of the diaphragm member 103.

The diaphragm member 103 has a deformable vibration region 130 that forms the 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 by a first layer that forms a thin wall portion from the flow path plate 102 side and a second layer that forms a thick wall portion. A deformable vibration region 130 is formed in a portion corresponding to the individual liquid chamber 106.

Then, on the side of the diaphragm member 103 opposite 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 is included. Is placed.

In the piezoelectric actuator 111, the piezoelectric members joined on the base member 113 are grooved by half-cut dicing to form a required number of columnar piezoelectric elements 112 in a comb-teeth shape at predetermined intervals.

Then, the piezoelectric element 112 is joined to the convex portion 130a, which is an island-shaped thick portion formed in the vibration region 130 of the diaphragm member 103. Further, a flexible wiring member 115 is connected to the piezoelectric element 112.

The common liquid chamber member 120 forms a common liquid chamber 110 on the supply side and a common liquid chamber 150 on the recovery side. The supply-side common liquid chamber 110 is connected to the supply port (supply port) 171 and the recovery-side common liquid chamber 150 is connected to the recovery port (collection port) 172.

Here, the common liquid chamber member 120 is composed of 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 joined to the first common liquid chamber member 121.

The first common liquid chamber member 121 forms a downstream common liquid chamber 110A, which is a part of the supply side common liquid chamber 110 leading to the liquid introduction portion 108, and a recovery side common liquid chamber 150 leading to the recovery flow path 151. ing. Further, the second common liquid chamber member 122 forms the upstream common liquid chamber 110B, which is the remainder of the supply side common liquid chamber 110.

Further, the flow path plate 102 is formed with a recovery 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 passage 105. The recovery flow path 151 leads to the recovery side common liquid chamber 150.

In this liquid discharge head, for example, by lowering the voltage applied to the piezoelectric element 112 from the reference potential (intermediate potential), the piezoelectric element 112 contracts, the vibration region 130 of the vibrating plate member 103 is pulled, and the volume of the individual liquid chamber 106 is reached. As the liquid expands, the liquid flows into the individual liquid chamber 106.

After that, 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 vibrating plate 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 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 again from the recovery side common liquid chamber 150 to the supply side common liquid chamber 110 through an external circulation path. Will be supplied.

The method of driving the head is not limited to the above example (pull-push), and pulling or pushing may be performed depending on the driving waveform.

Next, a portion related to the liquid circulation device according to the first embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block explanatory diagram provided for the same explanation.

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

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

Further, the first manifold 230 and the second manifold 240 through which the plurality of heads 100 pass, the first head tank 300a and the second head tank 300b for each head 100, and the degassing means for removing the dissolved gas in the liquid. It is equipped with a degassing device 260. The first head tank 300a and the second head tank 300b are referred to as a head tank (or buffer tank) 300 when not distinguished.

Here, the third sub-tank 290 is arranged between the first sub-tank 220 and the second sub-tank 210, and the third sub-tank 209 is used from the main tank 201 via the liquid path 289 which is a replenishment path including the filter 205. 3 Liquid is sent (replenished) to the sub tank 290.

The third sub-tank 290 is provided with a liquid level detecting means 291 and a solenoid valve 292 that constitutes an atmospheric opening mechanism that opens the inside to the atmosphere.

The third sub-tank 290 and the second sub-tank 210 are connected to each other through a liquid path 283, and a second liquid feeding pump 203 is provided in the liquid path 283. Further, the third sub tank 290 and the second sub tank 210 are connected to each other through a backflow liquid path 285, and a solenoid valve 287 is provided in the backflow liquid path 285.

The second sub-tank 210 has a gas chamber 210a, and is configured such that a liquid and a gas coexist. The second sub-tank 210 is provided with a liquid level detecting means 211 for detecting the liquid level and a solenoid valve 212 as an atmospheric opening mechanism for opening the inside to the atmosphere.

The third sub-tank 290 and the first sub-tank 220 are connected to each other through a liquid path 284, and a first liquid feeding pump 202 is provided in the liquid path 284. Further, the third sub tank 290 and the first sub tank 220 are connected to each other through a backflow liquid path 286, and a solenoid valve 288 is provided in the backflow liquid path 286.

The first sub-tank 220 has a gas chamber 220a, and is configured such that a liquid and a gas coexist. The first sub-tank 220 is provided with a liquid level detecting means 221 for detecting the liquid level and a solenoid valve 222 as an atmospheric opening 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 degassing device 260 and a filter 261.

The first manifold 230 is connected to the supply port 171 (supply port) side of the head 100 via the 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 a solenoid valve 232 that opens and closes a path upstream of the first head tank 300a. The solenoid valve 232 is provided according to the number of heads 100, and can be individually opened and closed. Further, the pressure sensor 233 is provided on the first manifold 230.

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

The second manifold 240 is connected to the collection port 181 (collection port) side of the head 100 via the collection 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 a solenoid valve 242 that opens and closes a path downstream of the second head tank 300b. The solenoid valve 242 is provided according to the number of heads 100, and can be individually opened and closed. Further, the pressure sensor 243 is provided on the second manifold 240.

Further, a bypass path 270 is provided through the first manifold 230 and the second manifold 240. The bypass path 270 has a solenoid valve 271 which is a bypass opening / closing means on the first manifold 230 side, and the liquid path 282 between the second manifold 240 and the second sub tank 210 has a solenoid valve 272 which is a recovery side opening / closing means. Is provided.

Here, from the third sub tank 290, the third sub tank 290 passes through the liquid path 284, the first sub tank 220, the liquid path 281, the deaerator 260, the first manifold 230, the head 100, the second manifold 240, and the second sub tank 210. The circulation route 280 is configured by the route returning to.

Further, the solenoid valves 232, 242, and 271 cut off the space between the head 100 and the circulation path 280, and the bypass path 270 forms a part of the circulation path 280, and the bypass path 270 and the circulation path 280. The space is cut off, and the head 100 constitutes a means for switching from the second path forming a part of the circulation path 280.

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

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

Further, the first sub-tank 220, the second sub-tank 210, the first liquid feeding pump 202, and the second liquid feeding pump 203 constitute a means for generating a pressure for the liquid to circulate in the circulation path 280.

Next, the supply and circulation of the liquid will be described.

In the liquid feeding (replenishment) from the main tank 201 to the third sub tank 290, when the liquid level detecting means 291 of the third sub tank 290 detects a shortage of liquid, the third liquid feeding pump 209 is used to feed the liquid from the main tank 201. Through the liquid path 289, the liquid level detecting means 291 supplies the liquid to the third sub tank 290 until the liquid level is full.

The liquid is fed from the third sub tank 290 to the first sub tank 220 by using the first liquid pump 202 to supply the liquid from the third sub tank 290 to the first sub tank 220 via the liquid path 284.

The liquid is supplied from the second sub tank 210 to the third sub tank 290 by using the second liquid pump 203 to supply the liquid from the second sub tank 210 to the third sub tank 290 via the liquid path 283.

The liquid transfer 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.

That is, the liquid is supplied to the first sub tank 220 by the first liquid feeding pump 202 until the target pressure (for example, the pressure to be pressurized) 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 pressure that becomes a negative pressure) is reached by the pressure sensor 243 of the second manifold 240.

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

In response to this differential pressure, from the first sub-tank 220 via the liquid path 281, a filter 261 and a deaerator 260, a first manifold 230, a plurality of supply paths 231 and a plurality of first head tanks 300a and a plurality of heads 100. The liquid can be circulated to the second sub tank 210 via the plurality of recovery paths 241 and the plurality of second head tanks 300b, 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 solenoid valve 232 and 242 are closed and the solenoid valve 271 is opened, the first liquid feed pump 202 and the second liquid feed pump 203 are driven to generate a differential pressure. Liquid circulation from the first sub tank 220 to the second sub tank 210 via the filter 261, the deaerator 260, the first manifold 230, the bypass path 270, the second manifold 240, and the liquid path 282 via the liquid path 281. It will be possible.

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

Further, each sub-tank 210, 220, 290 is provided with solenoid valves 212, 222, 292 as an atmosphere opening mechanism, respectively, and by controlling this, each sub-tank 210, 220, 290 communicates 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 of the liquid is in contact with, for example, air.

Here, when the pressurized state of air is generated in the first sub-tank 220 and the depressurized state of air is generated in the second sub-tank 210, the gas has compressibility, so that pressure can be stored. 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 feeding pump 202 and the second liquid feeding pump 203 communicating with the first sub tank 220 and the third sub tank 290, 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 the overflow of the liquid and the entrainment of air bubbles.

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

Next, a configuration relating to bubble discharge during liquid filling in the liquid circulation device 200 will be described.

In the present embodiment, the third sub-tank 290 is a confluence portion where the circulation path 280 and the liquid path 289, which is a replenishment path, meet. Then, it is a switching means for switching the connection and disconnection between the drainage path 402 branching from the liquid path 283 on the upstream side of the third sub tank 290 and the liquid path 283 constituting the drainage path 402 and the circulation path 280. It is equipped with a drain valve 401.

The drain valve 401 is a three-way valve that has three entrances and exits and can selectively switch between the three paths. The drain valve 401 may be manually switched, which is composed of an electrically driven solenoid valve.

One inlet / outlet of the drain valve 401 is connected to the downstream side of the second liquid feed pump 203 of 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 entrance / exit 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 inlet / outlet 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 connection between the downstream of the connection point a downstream of the backflow liquid path 285 and the upstream of the third subtank 290 and the downstream of the backflow liquid path 285 is communicated with the liquid path 283. It is possible to selectively switch between the second path in which the downstream of the point a and the drainage path 402 communicate with each other and the third path in which the upstream side of the third sub-tank 290 and the drainage path 402 communicate with each other. 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 leading to the drainage path 402 is provided with a solenoid valve 404 that enables communication with the atmosphere and a pressure sensor 406. The drainage tank 403 preferably has a capacity that exceeds the volume of all 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 order to raise air bubbles in the path by buoyancy. ing.

Further, it is preferable that the drainage tank 403 is arranged above the drainage path 402, and the drainage path 403 is connected at the bottom of the drainage tank 403.

Further, in the present embodiment, in order to replaceably attach / detach the head 100 to / from the supply path 231 and the recovery path 241, the head assembly 400 including the head 100, the first head tank 300a, the second head tank 300b, and the coupling 405 is included. Consists of.

The head assembly 400 can be interchangeably attached to and detached from the supply path 231 and the recovery path 241 by the coupling 405.

The disconnection at the coupling 405 allows the head 100 to take an individual state. Therefore, the filling liquid can be pre-filled in the state of the head assembly 400. Therefore, in the present embodiment, in the initial state, the head assembly 400 is pre-filled with a filling liquid having good wettability or a predetermined liquid.

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

The control unit 500 includes a main control unit 500A composed of a CPU 501 that controls the entire device, 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 non-volatile memory 504 (NVRAM) for holding data even while the power of the device is cut off. The control unit 500 includes an ASIC 505 that processes various signal processing for image data, image processing that performs sorting, and other input / output signals for control, and is connected to a printer driver 590 via a host I / F 506. Send and receive data with.

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

The control unit 500 includes a solenoid valve control unit 510 that drives and controls the solenoid valves 232, 242, 271 and the solenoid valves 212, 222, 292, 287, 288, etc. of the solenoid valve group 550. The control unit 500 includes a supply system control unit 511 that drives and controls the third liquid feed pump 209.

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

The control unit 500 has an I / O unit 513. The I / O unit 513 can process various sensor information, and acquires the detection results of the pressure sensors 233 and 243 and the information from various sensor groups 515. Then, the information necessary for controlling the device is put out and used for control by the print control unit 508, the solenoid valve control unit 510, the supply system control unit 511, the pressure system control unit 512, and the like.

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

Next, the liquid filling operation in this embodiment will be described with reference to FIGS. 7 and 8. 7 and 8 are explanatory views for explaining the operation.

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

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 solenoid valve 271 in the bypass path 270 is opened.

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

The liquid 600 to be filled in the circulation path 280 is stored in the main tank 201. The solenoid 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 feeding pump 209 when the liquid level height reaches a predetermined position. After that, the third liquid feed pump 209 is driven according to the detection result of the liquid level height of the liquid level detecting means 291 and the liquid supply (replenishment) operation to the third sub tank 290 is repeated.

Next, the solenoid valve 222 of the first sub tank 220 is opened to communicate with the atmosphere. The solenoid valve 292 of the third sub-tank 290 is closed in order to fill the backflow liquid path 286 with the liquid 600. As a result, the third sub tank 290 is sealed, and the third liquid feed pump 209 is driven in this state. The backflow liquid path 286 is filled by feeding the liquid for a predetermined time or a predetermined amount. After that, the solenoid valve 288 is closed and the solenoid valve 292 is opened.

Next, with the solenoid valve 222 of the first sub-tank 220 communicating with the atmosphere in the open state, the first liquid feed pump 202 is driven, and the liquid is supplied to the first sub-tank 220 until the liquid level detecting means 221 detects it. Fill and stop the first liquid feed pump 202. After the first liquid feeding pump 202 is stopped, the solenoid valve 222 is closed, and the first sub tank 220 is filled with a predetermined amount of liquid and then sealed.

In this state, the drain valve 401 communicates with the connection point a downstream of the second liquid feed pump 203 and the drainage path 402, and the liquid path 283 and the third sub tank 290 are cut off (“x” in FIG. 7). Is attached.) Switch to the second state.

Here, by driving the first liquid feeding pump 202 and the second liquid feeding pump 203, the positive pressure in the gas chamber 220a of the first sub tank 220 rises, and the gas chamber 210a in the second sub tank 210 becomes 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.

The pressure difference can be set according to the state of air discharge and liquid movement, and the filling method is performed by adjusting the pump driving force of each of the first liquid feed pump 202 and the second liquid feed 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 feeding pump 203 is stopped in a state where the inside of the drainage path 402 is filled with the liquid. Then, the solenoid 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 is detected by the liquid level detecting means 211 of the second sub tank 210, the first liquid feeding pump 202 is stopped, so that the inside of the second sub tank 210 is filled with a predetermined amount of liquid. ..

After that, the solenoid valve 212 of the second sub-tank 210 is closed, and the second sub-tank 210 is closed. Then, by opening the solenoid valve 287 of the backflow liquid path 285 and driving the first liquid feed pump 202 again, the backflow liquid path 285 is filled with the liquid. After filling, the solenoid valve 287 is closed.

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

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

By the above-mentioned 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 and the deaerator 260, the first manifold 230, the bypass path 270, the second manifold 240, The liquid 600 is to be filled up to the downstream of the connection point a downstream of the liquid path 282, the second sub tank 210, the backflow liquid path 285, and the backflow liquid path 285 and the drainage path 402.

Here, when the drainage path 402 is cut off from the circulation path 280 to form a path for communicating 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 are formed. The route will be opened with air remaining in the section.

In this case, air may flow into the third sub-tank 290, causing bubbles to be generated in the third sub-tank 290, resulting in malfunction of the liquid level detecting means 291 and leakage of bubbles from the solenoid valve 292. be.

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

After that, as shown in FIG. 8, the route is switched by the drain valve 401, and the third state is set in which the drainage tank 403 communicates with the upstream side of the third sub-tank 290 via the drainage path 402.

By driving the third liquid feed pump 209, the liquid in the third sub tank 290 moves toward the drain tank 403, and the upstream side of the third sub tank 290 and the liquid path 283 of the drainage path 402 The path to the connection is filled with 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 drain valve 401 is switched to a state in which the drain valve 402 is separated 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.

After that, the liquid filling in 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 paths other than the head assembly libri 400 are described in an empty state, but the filling liquid or the like may be filled in advance as in the head assembly 400. In this case, the filling liquid in the piping path other than the head assembly 400 is replaced with the liquid by sending the liquid to be filled while discharging the filling liquid previously filled in the drainage tank 403. Further, 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 significantly shortened.

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

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

As a result, the air or the liquid with the bubbles 407 sent from the liquid path 283 to the drainage path 402 is discharged to the drainage tank 403, the bubbles 407 are raised by buoyancy, and the air layer is accumulated upward. Bubbles 407, which are lighter than the liquid, always try to head toward the beginning of the liquid flow in the drainage path 402, resulting in gas-liquid separation in the drainage tank 403.

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

Next, the second embodiment of the present invention will be described with reference to FIG. FIG. 10 is an explanatory diagram of a portion 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, it is possible to suppress the generation of bubbles 407 and further shorten the filling operation.

The drain valve 401 has three doorways that are opened and closed by the valve bodies 408, 409, and 410. The entrance / exit portion of the drain valve 401 having the valve body 409 is directly connected to the side wall 290a so as to be a part of the side wall 290a of the third sub tank 290.

The doorway of the other two-way valve body 408 is connected to the liquid path 283, and the doorway having the valve body 410 is connected to the drainage path 402.

The inside of the drain valve 401 is configured with flow paths divided in three directions, and by combining the operations of the valve bodies 408, 409, and 410, it is possible to form a flow path in three directions.

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 the downstream of the connection point a downstream of the backflow liquid path 285 and the drainage path 402 are opened, 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, the liquid filling in the head 100 will be described with reference to FIG. FIG. 11 is an explanatory diagram of the suction mechanism portion provided for the same explanation.

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 via the waste liquid path 702, and the like.

Then, after the filling other than the head 100 is completed, the cleaning liquid is sucked and discharged from the nozzle 104 by the suction mechanism unit 700 to replace the liquid and the head 100 is also filled with the liquid.

Further, apart from suction, it can also be performed by pressurizing and filling the head 100 with a liquid and discharging the liquid from the nozzle.

For example, the solenoid valve 272 downstream of the second manifold 240 is closed and the solenoid valve 271 of the bypass path 270 is opened. By driving the first liquid feeding pump 202 in this state, positive pressure is applied to both the first manifold 230 and the second manifold 240, and the liquids in the supply path 231 and the recovery path 241 connected to the plurality of heads 100 are applied. 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 liquid in both the circulation direction and the direction opposite to the circulation direction is used.

When the second liquid feed pump 203 is reversely driven, the liquid flows in the second manifold 240 in the direction opposite to the circulation, and a positive pressure is applied to the recovery path 241. At the same time, by driving the first liquid feeding 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 discharged may have a viscosity and surface tension that can be discharged from the head, and is not particularly limited, but has a viscosity of 30 mPa · s or less at room temperature, under normal pressure, or by heating or cooling. Is preferable. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, functionalizing materials such as surfactants, biocompatible materials such as DNA, amino acids and proteins, and calcium. , Solvents, suspensions, emulsions, etc. containing edible materials such as natural pigments, such as inks for inkjets, surface treatment liquids, components of electronic and light emitting elements, and formation of electronic circuit resist patterns. It can be used in applications such as liquids and material liquids for three-dimensional modeling.

The "liquid discharge head" includes a piezoelectric actuator (laminated piezoelectric element and thin film type piezoelectric element), a thermal actuator using an electric heat conversion element such as a heat generating resistor, a vibrating plate and a counter electrode as an energy generation source for discharging liquid. Includes those that use electrostatic actuators and the like.

The "device for discharging a liquid" includes a device for driving a liquid discharge head to discharge a liquid. The device for discharging a liquid includes not only a device capable of discharging a liquid to a device to which the liquid can adhere, but also a device for discharging the liquid into the air or into the liquid.

The "device for discharging the liquid" can also include means for feeding, transporting, and discharging paper to which the liquid can adhere, as well as a pretreatment device, a posttreatment device, and the like.

For example, as a "device that ejects a liquid", an image forming device that is a device that ejects ink to form an image on paper, and a three-dimensional object (three-dimensional object) are formed in layers in order to form a three-dimensional object. There is a three-dimensional modeling device (three-dimensional modeling device) that discharges the modeling liquid into the powder layer.

Further, the "device for discharging a liquid" is not limited to a device in which a significant image such as characters and figures is visualized by the discharged liquid. For example, those that form patterns that have no meaning in themselves and those that form a three-dimensional image are also included.

The above-mentioned "thing to which a liquid can adhere" means a material to which a liquid can adhere at least temporarily, such as a material to which the liquid adheres and adheres, and a material to which the liquid adheres and permeates. Specific examples include paper, recording paper, recording paper, film, recorded media such as cloth, electronic substrates, electronic components such as piezoelectric elements, powder layers (powder layers), organ models, and media such as inspection cells. Yes, and includes everything to which the liquid adheres, unless otherwise specified.

The material of the above-mentioned "material to which a liquid can adhere" may be paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics or the like as long as the liquid can adhere even temporarily.

Further, the "device for discharging the liquid" includes, but is not limited to, a device in which the liquid discharge head and the device to which the liquid can adhere move relatively. Specific examples include a serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like.

In addition, as a "device for ejecting a liquid", a treatment liquid coating device for ejecting a treatment liquid to the paper in order to apply the treatment liquid to the surface of the paper for the purpose of modifying the surface of the paper, etc. There is an injection granulation device that granulates fine particles of raw materials by injecting a composition liquid in which raw materials are dispersed in a solution through a nozzle.

In addition, in the term of this application, image formation, recording, printing, printing, printing, modeling, etc. 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 sub tank 220 1st sub tank 230 1st manifold 240 2nd manifold 260 degassing device 270 Bypass path 280 Circulation path 290 3rd sub tank 401 Drain Valve (switching means)
402 Drainage route 403 Drainage tank 1000 Printing device (device that discharges liquid)

Claims (8)

A circulation path in which the liquid supplied to the liquid discharge head and collected from the liquid discharge head circulates.
A supply route for supplying the liquid to the circulation route and a supply route.
A drainage path that branches off from the circulation path on the upstream side of the confluence where the circulation path and the replenishment path meet.
A switching means for switching communication and interruption between the drainage path and the circulation path is provided .
In the circulation path,
The first sub-tank leading to the supply port of the liquid discharge head and
The second sub-tank leading to the collection port of the liquid discharge head and
A third sub-tank, which is located between the first sub-tank and the second sub-tank and is supplied with the liquid through the replenishment path, comprises.
The drainage path branches from between the second sub-tank and the third sub-tank.
A liquid circulation device characterized by that. The switching means is
The first state that blocks the drainage path and the circulation path,
A second state in which the second sub-tank side and the drainage path are communicated with each other and the drainage path and the third sub-tank side are blocked.
The first aspect of claim 1 , wherein the third sub-tank side and the drainage path are communicated with each other, and the drainage path and the second sub-tank side can be switched to a third state. Liquid circulation device. The liquid circulation device according to claim 1 or 2 , wherein the connecting portion of the switching means connected to the third sub-tank is connected in the liquid stored in the third sub-tank. The liquid circulation device according to any one of claims 1 to 3 , wherein the switching means is integrated with the wall portion of the third sub tank. A bypass path connecting the upstream and downstream of the liquid discharge head,
The liquid circulation device according to any one of claims 1 to 4 , further comprising a bypass opening / closing means for opening / closing the bypass path. A first liquid feeding means provided between the first sub-tank and the third sub-tank to feed a liquid toward the liquid discharge head is provided.
A collection side opening / closing means for opening / closing between the liquid discharge head and the second sub tank is provided.
The liquid circulation device according to claim 5 , wherein when the liquid discharge head is filled with the liquid, the collection side opening / closing means is closed and the liquid is fed by the first liquid feeding means. A first liquid feeding means provided between the first sub-tank and the third sub-tank to feed a liquid toward the liquid discharge head, and a liquid feeding means.
A second liquid feeding means, which is provided between the second sub-tank and the third sub-tank and is a reversible type capable of feeding liquid in both directions, is provided.
When the liquid discharge head is filled with the liquid, the liquid is fed by the first liquid feeding means, and the second liquid feeding means sends the liquid toward the liquid discharge head.
The liquid circulation device according to claim 5 . With multiple liquid discharge heads,
A device for discharging a liquid, which comprises the liquid circulation device according to any one of claims 1 to 7 .

Images