JP6996164B2 - Device that discharges liquid - Google Patents

Description

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

When performing degassing circulation in a device using a flow-through type liquid discharge head (hereinafter, also simply referred to as "head"), if the circulation is performed to the inside of the head, the circulation flow rate increases because the flow path in the head is small. It takes less time to degas.

Therefore, conventionally, there is a method in which a bypass path (flow path) for bypassing and circulating the head is provided so that the head is first bypassed and circulated (Patent Document 1).

Japanese Patent No. 5209431

As described above, when the circulation for degassing is performed by bypassing the head, the liquid that is not degassed remains around the head including the inside of the head. Therefore, when switching from the circulation path bypassing the head to the circulation path passing through the head, the problem is that the liquid with a low degree of degassing around the head and the liquid with a high degree of degassing that have been degassed are rapidly mixed and bubbles are generated. There is.

The present invention has been made in view of the above problems, and an object of the present invention is to reduce the generation of bubbles when switching the degassing circulation path.

In order to solve the above problems, the device for discharging the liquid according to claim 1 of the present invention is
A liquid storage means for storing liquid and
The circulation path through which the liquid of the liquid storage means circulates,
The liquid discharge head provided in the circulation path and
A bypass path connecting the upstream and downstream of the liquid discharge head in the circulation path,
A means for switching between a first route in which the bypass route is a part of the circulation route and a second route in which the bypass route is not included in the circulation route.
A means for generating a pressure for the liquid to circulate in the circulation path,
The degassing means for removing the gas in the liquid and
A degassing control means for controlling the circulation and degassing of the liquid is provided.
The liquid storage means includes a first tank and a second tank, and includes a first tank and a second tank.
The pressure at which the liquid circulates is the differential pressure between the first tank and the second tank.
The degassing control means is
After performing the first degassing operation for circulating the liquid in the first path, the control is performed by switching to the second path and performing the second degassing operation for circulating the liquid in the second path.
In the second degassing operation, the control is performed to start the circulation of the liquid at a differential pressure lower than the differential pressure in the first degassing operation.

According to the present invention, it is possible to reduce the generation of bubbles when switching the degassing circulation path.

It is a schematic explanatory drawing of an example of the apparatus which discharges 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 a block explanatory drawing which provides the explanation of the part which concerns on the liquid supply circulation in 1st Embodiment of this invention. It is a block diagram which provides the outline of the part which concerns on the supply circulation control of the control part in the same embodiment. It is a schematic diagram when the same embodiment is modeled as an equivalent circuit. It is a flow figure which provides the explanation of the control of the 1st degassing operation (process) in the same embodiment. Similarly, it is a flow diagram which provides the explanation of the control of the 2nd degassing operation (process). It is explanatory drawing which showed the contour line of the pressure and the flow rate of the meniscus in the case of Rr = 1. It is a block explanatory drawing which provides the explanation of the part which concerns on the liquid supply circulation in the 2nd Embodiment of this invention. It is a flow diagram which provides the explanation of the control of the 1st degassing operation (process) before the start of discharge in the same embodiment. Similarly, it is a flow diagram which provides the explanation of the control of the 2nd degassing operation (process). It is a block explanatory drawing which provides the explanation of the part which concerns on the liquid supply circulation in the 3rd Embodiment of this invention. It is a block explanatory drawing which provides the explanation of the part which concerns on the liquid supply circulation in 4th Embodiment of this invention. It is a block explanatory drawing which provides the explanation of the part which concerns on the liquid supply circulation in 5th Embodiment of this invention. It is a block diagram which provides the outline of the part which concerns on the supply circulation control of the control part in the same embodiment. It is a block explanatory drawing which provides the explanation of the part which concerns on the liquid supply circulation in the 6th Embodiment of this invention.

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 with respect to 10, a drying means 7 for drying the continuum 10, a discharging means 9 for discharging 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 discharging means 9, and is guided and conveyed by the winding roller 91 of the discharging means 9. It is wound up at.

In the printing means 5, the continuum 10 is conveyed on the transfer guide member 59 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).

In this liquid discharge head, a nozzle plate 101, a flow path plate 102, and a diaphragm member 103 as a wall surface member are 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 discharge side. The supply-side common liquid chamber 110 is connected to the supply port 171 and the discharge-side common liquid chamber 150 is connected to the discharge-side port 181.

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 discharge side common liquid chamber 150 leading to the discharge 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 discharge flow path 151 along the surface direction of the flow path plate 102 that communicates with each individual liquid chamber 106 via the nozzle communication passage 105. The discharge flow path 151 leads to the discharge 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 that is not discharged from the nozzle 104 passes through the nozzle 104 and is discharged from the discharge flow path 151 to the discharge side common liquid chamber 150, and is again discharged from the discharge 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, the portion related to the liquid supply circulation in the first embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block explanatory diagram provided for the same explanation.

The liquid supply device 200 includes a main tank 201, a first sub tank 220, a second sub tank 210, a third sub tank 290, and a first liquid feed pump 202, which are liquid storage means for storing the liquid 300 discharged from the head 100. A second liquid feeding pump 203 and a third liquid feeding pump 209 are provided.

Further, the first manifold 230 and the second manifold 240 through which the plurality of heads 100 pass, the pressurized head tank 251 and the depressurized head tank 252 for each head 100, and the degassing means for removing the dissolved gas in the liquid. It is equipped with a gas device 260.

Here, the third sub-tank 290 is arranged between the first sub-tank 220 and the second sub-tank 210, and is connected to the third sub-tank 290 by the third liquid feed pump 209 from the main tank 201 via the liquid path 289 including the filter 205. Send (supply) liquid.

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 pressure head tank 251. The supply path 231 is provided with a solenoid valve 232 that opens and closes the path upstream of the pressure head tank 251. 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 discharge port 181 (discharge port) side of the head 100 via the discharge path 241. The discharge path 241 is connected to the discharge port 181 of the head 100 via the decompression head tank 252. The discharge path 241 is provided with a solenoid valve 242 that opens and closes the path downstream of the pressure reducing head tank 252. Further, the pressure sensor 243 is provided on the second manifold 240.

Further, a bypass path 270 is provided through the first manifold 230 upstream of the head 100 and the second manifold 240 downstream of the head 100. The bypass path 270 is provided with a solenoid valve 271 on the first manifold 230 side and a solenoid valve 272 on the second manifold 240 side.

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. A circulation route is constructed by the route returning to.

Further, the bypass path 270 is a path connecting the first manifold 230 and the second manifold 240, and is a path connecting the upstream and the downstream of the head 100 in the circulation path.

Further, the solenoid valves 232, 242, 271, and 272 block the space between the head 100 and the circulation path, and the bypass path 270 forms a part of the circulation path, and the bypass path 270 and the circulation path are separated from each other. The space is cut off, and the head 100 constitutes a means for switching to a second path constituting a part of the circulation path.

That is, by closing the solenoid valves 232 and 242 and opening the solenoid valves 271 and 272, the bypass path 270 becomes a part of the circulation path, and the head 100 does not become a part of the circulation path.

Further, by opening the solenoid valves 232 and 242 and closing the solenoid valves 271 and 272, the head 100 becomes a part of the circulation path, and the bypass path 270 and the second path which does not become a part of the circulation path are configured.

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.

Here, 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.

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. .. This pressure change is transmitted through the liquid path, and when it is transmitted to the nozzle meniscus, it leads to the overflow of 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 compliance component. By having the gas chambers 220a and 210a, it becomes possible to suppress the pressure change (pulsation).

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

The control unit 500 comprises a CPU 501 that controls the entire device, a ROM 502 that stores fixed data such as various programs including a program executed by the CPU 501, and a RAM 503 that temporarily stores image data and the like, according to the present invention. It includes a main control unit 500A that also serves as a control means.

The control unit 500 includes a rewritable non-volatile memory 504 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 for rearranging images, and other input / output signals for control.

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 223, 242, 271, 272 and the solenoid valves 212, 222, 292, 287, 288, etc. of the solenoid valve group 550.

The control unit 500 includes a supply system drive 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 extracted 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 circulation method in the circulation device of the present embodiment will be described.

(1) Liquid flow from the main tank 201 to the third sub tank 290 When the liquid level detecting means 291 detects a liquid shortage in the third sub tank 290, the third liquid feed pump 209 is driven to drive the liquid path 289 from the main tank 201. The liquid is supplied to the third sub tank 290 until the liquid level is full according to the detection result of the liquid level detecting means 291.
(2) Liquid flow from the third sub-tank 290 to the first sub-tank 220 The liquid can be fed from the third sub-tank 290 to the first sub-tank 220 via the liquid path 284 by driving the first liquid feeding pump 202. can.
(3) Liquid flow from the second sub tank 210 to the third sub tank 290 The second liquid feed pump 203 is driven to send energy liquid from the second sub tank 210 to the third sub tank 290 via the liquid path 283. Can be done.

(4) Drive the first liquid feed pump 202 until the pressure detected by the liquid flow pressure sensor 233 of the first sub tank 220-circulating head 100-second sub tank 210 reaches the target pressure (for example, the pressure to be pressurized). Then, the liquid is supplied to the first sub tank 220. Further, the second liquid feeding pump 203 is driven until the detected pressure of the pressure sensor 243 reaches a target pressure (for example, a pressure that becomes a negative pressure), and the liquid is fed to the third sub tank 290.

As a result, a differential pressure is generated between the first sub tank 220 and the second sub tank 210. Depending on this differential pressure, the filter 261 and the deaerator 260, the first manifold 230, the plurality of supply paths 231 and the plurality of head tanks 251, the plurality of heads 100, and the plurality of heads 100 from the first sub tank 220 via the liquid path 281. The liquid can be circulated to the second sub tank 210 via the discharge path 241 of the above, the plurality of head tanks 252, the second manifold 240, and the liquid path 282.

At this time, the solenoid valve 271 and the solenoid valve 272 are closed, and the solenoid valve 232 and the solenoid valve 242 are opened.

On the other hand, when the solenoid valve 232 and the solenoid valve 242 are closed and the solenoid valve 271 and the solenoid valve 272 are opened, the first liquid feed pump 202 and the second liquid feed pump 203 are driven to generate a differential pressure. From the first sub-tank 220 via the liquid path 281, the filter 261. The liquid can be circulated to the second sub tank 210 via the degassing device 260, the first manifold 230, the bypass path 270, the second manifold 240, and the liquid path 282.

The liquid level detecting means 211, 221 and 291 include a float type detection of the liquid, a method of detecting the presence or absence of the liquid according to the output of the voltage detected by using at least two or more electrode pins, and other lasers. A liquid level detection method or the like can be used.

Further, by driving the solenoid valves 222, 212, 292, the inside of the first sub tank 220, the second sub tank 210, and the third sub tank 290 can be communicated with the atmosphere.

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

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

When a circulating liquid discharge head is used, it is common to set a positive pressure in the first sub tank 220 and set a negative pressure in the second sub tank 210.

More specifically, the fluid resistance Rin from the first sub-tank 220 to the nozzle 104 of the head 100 and the fluid resistance Rout from the nozzle 104 to the second sub-tank 210 are obtained in advance by calculation or measurement. Then, by setting the pressure Pin of the first sub-tank 220 and the pressure Pout of the second sub-tank 210 according to these fluid resistances Rin and Rout, the ratio of Rin and Rout and the ratio of Rout are similar to the partial pressure of the series resistance. Depending on the values of Pin and Pout, the target pressure Pn can be generated in the meniscus.

That is, if the circulating flow rate is I,
Pn-Pin = I × Rin
Pout-Pn = I × Rout
Here, by deleting I from both sides and transforming it, the equation (1) is obtained.

In this equation (1), if Rin = Rout, Pn = (Pout + Pin) / 2.

Therefore, it can be seen that the pressure of the meniscus is determined according to the set pressure and the fluid resistivity ratio.

Here, FIG. 7 shows a schematic diagram when modeled as an equivalent circuit.

This schematic diagram assumes a line head, and means that the module A communicates with the head 100, its supply path 231 and the circulation path (discharge path) 241. This is a configuration in which the required number (within the frame of B) is lined up in parallel.

Further, the first sub-tank 220, the second sub-tank 210, and the nozzle meniscus can be modeled as a capacitor component in which a voltage is accumulated. The liquid path can be modeled as a resistance component that causes a voltage drop.

Therefore, Rin is represented by the liquid path 281 (R1), a part of the first manifold 230 (R3), the supply path 231 (R4), and the head 100 from the supply port (supply port 171) to the nozzle 104 (R5). Can be done.

On the other hand, Rout is represented by the nozzle 104 of the head 100 to the discharge port (discharge port 181) (R6), the discharge path 241 (R7), a part of the second manifold 240 (R8), and the liquid path 282 (R2). Can be done.

Further, a voltage generated by using a voltage source (air pump or the like as a means) or a current source (liquid pump or the like as a means) (not shown) in the first sub tank 220 can be expressed as Pin.

On the other hand, a voltage generated by using a voltage source (air pump or the like as a means) or a current source (liquid pump or the like as a means) (not shown) in the second sub tank 210 can be expressed as Pout.

Further, usually, a part of the first manifold 230 (R3 ... R3 + 6n) and a part of the second manifold 240 (R8 ... R8 + 6n) are attached to calculate the pressure of the nozzle meniscus of each head 100. Depending on the position given, it must be considered as appropriate. However, since the resistance value is sufficiently small compared to other paths, it can be ignored in the calculation.

Further, depending on the actual piping method and the structure inside the liquid discharge head, the above equation may not be exactly the same, but basically, the above idea can be applied.

In the above description, an example in which the first sub tank 220 is set to a positive pressure is described, but the second sub tank 210 has a larger negative pressure than the first sub tank 220 while the first sub tank 220 is set to a negative pressure. By controlling the above, it is possible to generate a differential pressure to circulate the liquid.

The advantage of this configuration is that the first sub-tank 220 also has a negative pressure, so that the liquid can be circulated while reducing the possibility of the liquid dripping as compared with the above-mentioned configuration. However, when the fluid resistance in the head is large, the initial negative pressure of the nozzle meniscus becomes large on the negative pressure side, so that the pressure fluctuation range that can be discharged becomes narrow.

Here, in the equation (1), the ratio Rout / Rin of the fluid resistance Rout and the fluid resistance Rin is set to Rr (Rr = Rout / Rin), and when modified, the following equation (2) is obtained.

If the nozzle meniscus pressure Pn is a constant value, Pout can be expressed by a linear function of Pin with an intercept of (1 + Rr) × Pn and a slope of −Rr.

If Pin and Pout are set so as to satisfy this relationship, the differential pressure (Pin-Pout), which is the pressure for circulating the liquid, can be increased or decreased while keeping the pressure of the nozzle meniscus constant. can.

On the other hand, if the relational expression ((2)) is deviated and the size increases in the positive direction, the liquid tends to overflow from the nozzle. On the contrary, if it is increased in the negative direction, air bubbles are caught from the nozzle and the nozzle is likely to go down.

Therefore, it is important to change the differential pressure while maintaining the target nozzle meniscus pressure.

Next, the control of the degassing operation in the first embodiment will be described.

The degree of degassing tends to decrease in the vicinity of the first sub-tank 220 and the second sub-tank 210 where the gas-liquid interface exists.

Therefore, if a liquid having a low degree of degassing around the first sub-tank 220 and the second sub-tank 210 is flowed through the head 100 during circulation, bubbles may be formed in the head 100.

Therefore, in the first stage, a first degassing operation is performed in which the first path is configured with the bypass path 270 as a part of the circulation path, and the liquid in the path having a low degree of degassing is circulated without passing through the head 100. By doing so, the degree of degassing of the liquid is improved.

Next, the control of the first degassing operation (process) in the present embodiment will be described with reference to the flow chart of FIG.

First, the solenoid valve 271, the solenoid valve 232, the solenoid valve 272, and the solenoid valve 242 are closed. Subsequently, the driving of the first liquid feeding pump 202 and the second liquid feeding pump 203 is started.

Then, it is determined from the detection result of the pressure sensor 233 whether or not the target pressure Pin has been reached. At this time, if the target pressure Pin has not been reached, it is determined whether or not the predetermined time has elapsed, and if the predetermined time has not elapsed, the process returns to the determination process of whether or not the target pressure Pin has been reached.

Similarly, it is determined from the detection result of the pressure sensor 243 whether or not the target pressure Pout has been reached. At this time, if the target pressure Pout has not been reached, it is determined whether or not the predetermined time has elapsed, and if the predetermined time has not elapsed, the process returns to the determination process of whether or not the target pressure Pout has been reached.

Here, when the target pressure Pin or the target pressure Pout has not been reached even after the predetermined time has elapsed (when the predetermined time has elapsed), an error display is performed. That is, if the target pressures Pin and Pout are not reached even after a lapse of a predetermined time, the drive sources, the first liquid feed pump 202 and the second liquid feed pump 203, may be out of order, air leaks from the piping, or parts may be damaged. Since it is possible that there is an ink leak due to the above, it is considered as an error.

Then, when the target pressure Pin and the target pressure Pout are reached within the predetermined time, the solenoid valves 271 and 272 are opened and the bypass path 270 is passed through to communicate the first manifold 230 and the second manifold 240.

As a result, liquid circulation is performed in the first path from the first sub-tank 220 to the first sub-tank 220 via the liquid path 281, the first manifold 230, the bypass path 270, the second manifold 240, the liquid path 282, and the second sub-tank 210. Start.

After that, when the circulation for the target time is performed, the first degassing operation is terminated.

Here, the details of the control to the target pressure will be described.

The control to reach the target pressure is, for example, a method in which the detection results of the pressure sensor 233 and the pressure sensor 243 are fed back, and the liquid feed amounts of the first liquid feed pump 202 and the second liquid feed pump 203 are sequentially controlled. There may be. The control of the liquid feed amount of the first liquid feed pump 202 and the second liquid feed pump 203 is, for example, PID from the deviation between each detected value (detected pressure) and the target value (target pressure) of the pressure sensor 233 and the pressure sensor 243. It can be realized by a control method typified by control.

Next, the set amount of the circulation amount will be described.

From the liquid capacity of the circulatory device and the degassing performance of the degassing device 260, how much circulation should be performed is calculated or measured in advance, and how long the degassing is performed is determined in advance. It is preferable to carry out circulation for this time or longer to replace the liquid with a liquid having an increased degree of degassing.

Further, after the circulation for a predetermined time, it is preferable to release the pressure in preparation for the next degassing operation (degassing step) of the second stage. For example, by closing the solenoid valve 271 and the solenoid valve 272 and opening the solenoid valve 212, the solenoid valve 222, and the solenoid valve 292 provided in the atmospheric release mechanism, the pressure is released to the atmospheric pressure.

Next, after performing the first degassing operation, the bypass path 270 is separated from the circulation path to form a second path in which the head 100 is a part of the circulation path, and the second degassing operation for circulating the liquid is performed. I do.

The control of the second degassing operation (process) will be described with reference to the flow chart of FIG.

First, the solenoid valve 271, the solenoid valve 232, the solenoid valve 272, and the solenoid valve 242 are closed. Next, the solenoid valve 232 and the solenoid valve 242 are opened. In this state, when pressure is generated, circulation starts.

Then, it is reset to n = 0. n is a predetermined number of times when the pressure is gradually increased from the smaller side and changed.

After that, the driving of the first liquid feeding pump 202 and the second liquid feeding pump 203 is started.

Then, it is determined from the detection result of the pressure sensor 233 whether or not the target pressure Pin (n) has been reached. At this time, if the target pressure Pin (n) has not been reached, it is determined whether or not the predetermined time has elapsed, and if the predetermined time has not elapsed, whether or not the target pressure Pin (n) has been reached. Return to the determination process of.

Similarly, it is determined from the detection result of the pressure sensor 243 whether or not the target pressure Pout (n) has been reached. At this time, if the target pressure Pout (n) has not been reached, it is determined whether or not the predetermined time has elapsed, and if the predetermined time has not elapsed, whether or not the target pressure Pout (n) has been reached. Return to the discrimination process.

Here, when the target pressure Pin (n) or the target pressure Pout (n) has not been reached even after the predetermined time has elapsed (when the predetermined time has elapsed), an error is displayed as in the first step. I do.

Then, when the target pressure Pin (n) and the target pressure Pout (n) are reached within a predetermined time, a process of setting n = (n + 1) is performed, and the pressure detected by the pressure sensor 233 is the target pressure Pin (n). = Pin (n-1) + α is controlled so that the pressure detected by the pressure sensor 243 is the target pressure Pout (n) = Pout (n-1) + β.

That is, every time n is incremented (+1), α is set as the target pressure Pin, and β is added as the target pressure Pout, and the new target pressure is controlled so as to be the target pressure.

Then, after circulating for a predetermined time, it is determined whether or not n has reached a predetermined value, and until n reaches a predetermined value, n is incremented (+1) and the target pressure is controlled. Repeat the process of.

In this way, when the second degassing operation is performed, the liquid is started from a pressure lower than the target pressures Pin and Pout of the first degassing operation, that is, the liquid is circulated at a pressure lower than the pressure in the first degassing operation. Controlling to start.

As a result, the liquid having a low degree of degassing around the head 100 and the liquid having a high degree of degassing degassed in the first degassing operation are slowly mixed and can reduce the generation of bubbles due to the rapid mixing.

Then, in the second degassing operation, the pressure for circulating the liquid is gradually increased (may be continuous) from the lower side, and the circulation flow rate is gradually increased.

As a result, it is possible to shorten the time required for degassing by increasing the circulation flow rate while preventing the liquid having a low degree of degassing from forming bubbles in the head 100 as described above, thereby suppressing the generation of bubbles. It is possible to improve the degassing efficiency.

That is, since the decompression on the second sub-tank 210 side acts on the discharge port (discharge port 181) of the head 100, there is a possibility that bubbles may be generated from the liquid having a low degree of degassing. Once bubbles are formed, it takes time for the bubbles to dissolve in the liquid even if the liquid having a high degree of degassing that has passed through the first stage flows. In addition, it takes extra time because it needs to be degassed as much as it melts.

Therefore, in order to suppress the formation of bubbles, a small depressurization and a small pressurization associated therewith are applied at the initial stage of the second degassing operation (step). Then, when the liquid having a low degree of degassing is replaced with the liquid degassed in the first degassing operation, the pressure is changed so as to be high.

In this way, control is performed to replace the supply path 231, the inside of the head 100, and the discharge path 241 from a liquid having a low degree of degassing to a liquid having a high degree of degassing. In this case, the liquid having a low degree of degassing can be replaced by being pushed out to the next liquid having a high degree of degassing.

By performing such control, it is possible to replace the liquid having a low degree of degassing with a liquid having a high degree of degassing in a short time while suppressing the generation of bubbles on the discharge port side, and to shorten the degassing time. ..

In the process of the second degassing operation described above, as the n increases, the predetermined pressures (α and β) are added to the target pressures (Pin, Pout) in the previous stage, so that the differential pressure is increased stepwise. (Note that Pout and β are negative pressures).

In this case, although the target pressure is changed stepwise in the above process, the target pressure can be continuously changed with a required inclination.

Further, as described above, the pressure is changed between the pressure Pout and the pressure Pin so as to satisfy the relationship of the following equation (2).

Here, if the nozzle meniscus pressure Pn is set to a constant value, Pout can be expressed by a linear function of Pin in which (1 + Rr) × Pn is an intercept and −Rr is a slope.

If Pin and Pout are set so as to satisfy this relationship, the differential pressure (Pin-Pout) can be increased or decreased while keeping the pressure of the nozzle meniscus constant.

On the other hand, if the relational expression ((2)) is deviated and the ink increases in the positive direction, the ink tends to overflow from the nozzle. On the contrary, if it is increased in the negative direction, air bubbles are caught from the nozzle and the nozzle is likely to go down.

Therefore, it is important to change the differential pressure while maintaining the target nozzle meniscus pressure. Then, if the differential pressure is increased, the flow rate can be increased while maintaining the nozzle meniscus pressure.

This situation is shown in FIG. FIG. 10 is a diagram showing contour lines of the pressure and flow rate of the meniscus when Rr = 1.

For example, when Rr = 1, when the intercept is -2 kPa, the meniscus pressure Pn is -1 kPa. At this time, it becomes a linear function of intercept-2 kPa and slope -1, and the larger the positive pressure and the negative pressure (the larger the lower right), the larger the differential pressure and the larger the flow rate. As long as the relational expression of this straight line (Pout = -1 × Pin + 2 × Pn) is observed, the flow rate can be increased while keeping the meniscus pressure constant.

The same applies to the section of 0 kPa, and the flow rate can be increased while the meniscus pressure is 0 kPa. The relational expression at this time is Pout = -1 × Pin.

In this way, before ejection from the head or before the start of printing, circulation is performed to increase the degree of degassing of the liquid, so that even if a gas-liquid interface exists in the circulation device, the influence of air bubbles can be exerted. It can be reduced and reliability can be improved.

At this time, the total degassing time can be shortened by switching the path for circulating the liquid at the time of degassing or gradually changing the pressure.

Further, in the present embodiment, when the first sub-tank 220 and the second sub-tank 210 are excessively pressurized and depressurized, the backflow liquid paths 285 and 286 are referred to by the detection values of the pressure sensor 233 and the pressure sensor 243, respectively. The pressure can be released by opening the electromagnetic valves 287 and 288 provided in the above.

That is, by opening the solenoid valves 287 and 288, the second sub tank 210 and the third sub tank 290, and the third sub tank 290 and the first sub tank 220 communicate with each other via the backflow liquid path 285 and 286.

Therefore, even when a one-way pump such as a diaphragm pump is used as the first liquid feed pump 202 and the second liquid feed pump 203, excessive pressure can be released. In particular, the diaphragm pump has a life of about 10 times that of a tubing pump capable of sending liquid in both directions, so that the life of the device can be extended.

Next, the portion related to the liquid supply circulation in the second embodiment of the present invention will be described with reference to FIG. FIG. 11 is a block explanatory diagram provided for the same explanation.

In the present embodiment, one end of the bypass path 270 is connected to a liquid path 281 between the first manifold 230 and the deaerator 260, which is a liquid path upstream of the first manifold 230 (connection point). Let a).

Further, the other end of the bypass path 270 is connected to the liquid path 282 between the second sub tank 210, which is a liquid path downstream of the second manifold 240 (referred to as a connection point b).

Then, the solenoid valve 271 is arranged between the connection point a and the first manifold 230, and the solenoid valve 272 is arranged between the connection point b and the second manifold 240.

Further, a solenoid valve 273 is provided on the connection point a side of the bypass path 270, and a solenoid valve 274 is provided on the connection point b side of the bypass path 270.

Therefore, by closing the solenoid valves 271 and 272 and opening the solenoid valves 273 and 274, the bypass path 270 becomes a part of the circulation path, and the first manifold 230 and the second manifold 240 and each head 10 become a part of the circulation path. The first route that does not become is constructed.

Further, by opening the solenoid valves 271 and 272 and closing the solenoid valves 273 and 274, the first manifold 230 and the second manifold 240 and each head 10 become a part of the circulation path, and the bypass path 270 becomes a part of the circulation path. A second route is constructed that does not.

It is also possible to configure the solenoid valves 271 and 273 with one solenoid three-way valve and the solenoid valves 272 and 274 with one solenoid three-way valve.

Further, the pressure sensor 233 is provided at a position upstream of the connection point a to detect the pressure of the liquid path 281, and the pressure sensor 243 is provided at a position downstream of the connection point b to detect the pressure of the liquid path 282. There is.

As described above, in the present embodiment, the bypass path 270 has a starting point (connection point a) upstream of the first manifold 230 and downstream of the first sub tank 220, and downstream of the second manifold 240, the second sub tank. The end point (connection point b) is upstream from 210.

As a result, in the above-mentioned first embodiment, it is necessary to provide solenoid valves 232 and 242 in each supply path 231 and each discharge path 241 respectively, whereas in this embodiment, one common solenoid valve 271 and 272 are provided. It can be handled with, the configuration is simple, and space can be saved.

The configuration of the portion related to the supply circulation control of the control unit in the present embodiment is the same as that of the first embodiment. However, the solenoid valve control unit 510 also drives and controls the solenoid valves 273 and 274 with the change in the configuration of the solenoid valve. However, it does not have the solenoid valves 232 and 242 of the first embodiment.

Further, in the present embodiment, when switching from the first path to the second path, air bubbles are likely to be generated immediately downstream of the second manifold 240 (around the solenoid valve 272). Therefore, when opening the solenoid valve 272 which is the valve means for switching from the first path to the second path, it is preferable to open it slowly. As a result, liquids having different degassing degrees can be slowly mixed, and the generation of bubbles can be suppressed. In order to perform such control, a solenoid valve whose opening degree can be controlled is used as the solenoid valve 272, and the opening degree can be gradually increased so that the solenoid valve can be opened slowly.

Further, when switching from the first path to the second path, the solenoid valve 271 which is the first valve means and the solenoid valve 272 which is the second valve means are opened, but it is preferable to open the solenoid valve 272 first. That is, if the pressure control of the first path and the second path is not successful due to some trouble, liquids having different degassing degrees may be rapidly mixed to generate bubbles when the solenoid valve is opened. However, if the point where bubbles are generated is on the solenoid valve 272 side, the bubbles can pass through the degassing device 260 before passing through the head 100, so that the intrusion of bubbles into the head 100 can be reduced, and the intrusion of bubbles into the head 100 can be reduced. Bubbles may mix with the gas inside each sub-tank and disappear.

Next, the control of the first degassing operation (process) before the start of discharge in the present embodiment will be described with reference to the flow chart of FIG.

First, the solenoid valve 271, the solenoid valve 273, the solenoid valve 272, and the solenoid valve 274 are closed. Subsequently, the driving of the first liquid feeding pump 202 and the second liquid feeding pump 203 is started.

Then, it is determined from the detection result of the pressure sensor 233 whether or not the target pressure Pin has been reached. At this time, if the target pressure Pin has not been reached, it is determined whether or not the predetermined time has elapsed, and if the predetermined time has not elapsed, the process returns to the determination process of whether or not the target pressure Pin has been reached.

Similarly, it is determined from the detection result of the pressure sensor 243 whether or not the target pressure Pout has been reached. At this time, if the target pressure Pout has not been reached, it is determined whether or not the predetermined time has elapsed, and if the predetermined time has not elapsed, the process returns to the determination process of whether or not the target pressure Pout has been reached.

Here, when the target pressure Pin or the target pressure Pout has not been reached even after the predetermined time has elapsed (when the predetermined time has elapsed), an error display is performed.

Then, when the target pressure Pin and the target pressure Pout are reached within the predetermined time, the solenoid valves 273 and 274 are opened and the bypass path 270 is passed through to communicate the first sub-tank 220 and the second sub-tank 210.

As a result, the circulation of the liquid from the first sub-tank 220 to the second sub-tank 210 via the bypass path 270 starts.

After that, when the circulation for the target time is performed, the degassing operation of the first stage is completed.

Here, the control to the target pressure and the setting amount of the circulation amount are the same as those in the first embodiment.

Further, after the circulation for a predetermined time, it is preferable to release the pressure in preparation for the next second degassing operation (degassing step). For example, by closing the solenoid valve 271 and the solenoid valve 272 and opening the solenoid valve 212 and the solenoid valve 222 provided in the atmospheric release mechanism, the pressure is released to the atmospheric pressure.

Next, the control of the second degassing operation (process) will be described with reference to the flow chart of FIG.

First, the solenoid valve 271, the solenoid valve 273, the solenoid valve 272, and the solenoid valve 274 are closed. Next, the solenoid valve 271 and the solenoid valve 272 are opened. In this state, when pressure is generated, circulation starts.

Then, it is reset to n = 0. n is a predetermined number of times when the pressure is gradually increased from the smaller side and changed.

After that, the driving of the first liquid feeding pump 202 and the second liquid feeding pump 203 is started.

Then, it is determined from the detection result of the pressure sensor 233 whether or not the target pressure Pin (n) has been reached. At this time, if the target pressure Pin (n) has not been reached, it is determined whether or not the predetermined time has elapsed, and if the predetermined time has not elapsed, whether or not the target pressure Pin (n) has been reached. Return to the determination process of.

Similarly, it is determined from the detection result of the pressure sensor 243 whether or not the target pressure Pout (n) has been reached. At this time, if the target pressure Pout (n) has not been reached, it is determined whether or not the predetermined time has elapsed, and if the predetermined time has not elapsed, whether or not the target pressure Pout (n) has been reached. Return to the discrimination process.

Here, when the target pressure Pin (n) or the target pressure Pout (n) has not been reached even after the predetermined time has elapsed (when the predetermined time has elapsed), an error is displayed as in the first step. I do.

Then, when the target pressure Pin (n) and the target pressure Pout (n) are reached within a predetermined time, a process of setting n = (n + 1) is performed, and the pressure detected by the pressure sensor 233 is the target pressure Pin (n). = Pin (n-1) + α is controlled so that the pressure detected by the pressure sensor 243 is the target pressure Pout (n) = Pout (n-1) + β.

That is, every time n is incremented (+1), α is set as the target pressure Pin, and β is added as the target pressure Pout, and the new target pressure is controlled so as to be the target pressure.

Then, after circulating for a predetermined time, it is determined whether or not n has reached a predetermined value, and until n reaches a predetermined value, n is incremented (+1) and the target pressure is controlled. Repeat the process of.

As described above, also in the present embodiment, when the second degassing operation is performed, the generation of bubbles can be reduced by starting from a pressure lower than the target pressures Pin and Pout of the first degassing operation. Then, in the second degassing operation, the pressure for circulating the liquid is gradually increased (may be continuous) from the lower side, and the circulating flow rate is gradually increased to shorten the time required for degassing. .. As a result, it is possible to suppress the generation of bubbles and improve the degassing efficiency.

Next, the portion related to the liquid supply circulation in the third embodiment of the present invention will be described with reference to FIG. FIG. 14 is a block explanatory diagram provided for the same explanation.

In the present embodiment, in the configuration of the first embodiment, a reversible pump, for example, a tubing pump is used as the first liquid feed pump 202 and the second liquid feed pump 203.

As a result, even when the first sub-tank 220 and the second sub-tank 210 are excessively pressurized and depressurized, they are back-fed by the first liquid feeding pump 202 and the second liquid feeding pump 203 to release the pressure. Can be done.

Therefore, the reverse liquid path and the solenoid valve as in the first embodiment are not required, and the configuration is simplified.

Next, the portion related to the liquid supply circulation in the fourth embodiment of the present invention will be described with reference to FIG. FIG. 15 is a block explanatory diagram provided for the same explanation.

In the present embodiment, in the configuration of the second embodiment, a reversible pump, for example, a tubing pump is used as the first liquid feed pump 202 and the second liquid feed pump 203, as in the third embodiment.

Therefore, the reverse liquid path and the solenoid valve as in the second embodiment are not required, and the configuration is simplified.

Next, the portion related to the liquid supply circulation in the fifth embodiment of the present invention will be described with reference to FIG. FIG. 16 is a block explanatory diagram provided for the same explanation.

In the present embodiment, the liquid is sent from the second sub tank 210 to the first sub tank 220 by the first liquid feeding pump 202. Further, liquid is sent from the main tank 201 to the second sub tank 210 by the second liquid feeding pump 203.

A second adjusting device 207 for adjusting the pressure in the second sub tank 210 is connected to the second sub tank 210. The second adjusting device 207 has a pressure adjusting mechanism (regulator) 213, a decompression buffer tank 214, and a vacuum pump 215 which is a gas pump. Further, a solenoid valve 216 is provided between the regulator 213 and the pressure reducing buffer tank 214. The solenoid valve 217 is provided in the pressure reducing buffer tank 214.

A first adjusting device 206 for adjusting the pressure in the first sub tank 220 is connected to the first sub tank 220. The first adjusting device 206 has a pressure adjusting mechanism (regulator) 223, a pressurized buffer tank 224, and a compressor 225. Further, a solenoid valve 226 is provided between the regulator 223 and the pressurizing buffer tank 224. The pressurizing buffer tank 224 is provided with a solenoid valve 227.

The configuration of the portion from the first sub-tank 220 to the second sub-tank 210 via the head 10 or the bypass path 270 is the same as that of the first embodiment.

Next, the outline of the part related to the supply circulation control of the control unit in the present embodiment will be described with reference to FIG. FIG. 17 is a block diagram provided for the same explanation.

Here, the control unit 500 includes a supply system drive unit 511 that drives and controls the first liquid feed pump 202 and the second liquid feed pump 203. Further, the control unit 500 includes a pressure system control unit 532 that drives and controls the vacuum pump 215, the compressor 225, and the regulators 213 and 223. Other configurations are the same as those in the first embodiment.

The control of the first degassing operation and the second degassing operation in the present embodiment is the process of starting the drive of the first liquid feeding pump 202 and the second liquid feeding pump 203 of FIGS. 8 and 9 in the above-mentioned first embodiment. May be the process of starting the drive of the compressor 225 and the vacuum pump 215.

Next, the portion related to the liquid supply circulation in the sixth embodiment of the present invention will be described with reference to FIG. FIG. 18 is a block explanatory diagram provided for the same explanation.

In this embodiment, in the configuration of the sixth embodiment, the connection position of the bypass path 270 is the same as that of the second embodiment.

Therefore, the control of the first degassing operation and the second degassing operation is the process of starting the drive of the first liquid feeding pump 202 and the second liquid feeding pump 203 of FIGS. 12 and 13 in the above-mentioned second embodiment. The process of starting the drive of the compressor 22 and the vacuum pump 215 may be performed.

Next, the seventh embodiment of the present invention will be described with reference to FIG. 5 described above. The details of each part are as described above.

The liquid degassing step in this embodiment is as follows. First, all the solenoid valves 232, 242, 271 and 272 are opened. Next, the liquid is circulated using the pressurizing pump 202, the depressurizing pump 203, or the like.

The liquid path at this time is divided into two, one is a path toward the head 100 and the other is a path toward the bypass path 270 around the first manifold 230. Here, since the fluid resistance value of the head 100 is larger than the fluid resistance value of the bypass path 270, most of the liquid flows to the bypass path 270. Of course, even a liquid in the vicinity of the head 100 may circulate, albeit in a small amount.

Most of the liquid staying in the vicinity of the head 100 does not pass through the degassing device and is not degassed, but the other liquids are degassed by the degassing device. Then, after sufficient deaeration, the solenoid valves 271 and 272 are closed. As a result, the circulation path of the liquid becomes a path through the head 100.

Next, the liquid is circulated using the pressurizing pump 202 and the depressurizing pump 203. At this time, if the liquid that stays in the vicinity of the head 100 and has not been degassed and the liquid that has been degassed in the vicinity of the manifold are rapidly mixed, bubbles are generated. Therefore, it is preferable that the circulation pressure at this time is smaller than the previous circulation pressure (circulation pressure when circulating with all the solenoid valves open).

In this way, the liquid can be efficiently circulated even when all the solenoid valves 232, 242, 271, and 272 are open. That is, when the bypass path 270 becomes a part of the circulation path, it is not essential that the head 100 deviates from the circulation path.

Further, of course, the present embodiment may be combined with each of the above-described embodiments.

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" may 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 supply device 201 Main tank (liquid storage means)
202 1st liquid feeding pump (liquid feeding means)
203 Second liquid feed pump 210 Second sub tank 220 First sub tank 230 First manifold 240 Second manifold 260 Degassing device 270 Bypass path 1000 Printing device (device that discharges liquid)

Claims (9)

A liquid storage means for storing liquid and
The circulation path through which the liquid of the liquid storage means circulates,
The liquid discharge head provided in the circulation path and
A bypass path connecting the upstream and downstream of the liquid discharge head in the circulation path,
A means for switching between a first route in which the bypass route is a part of the circulation route and a second route in which the bypass route is not included in the circulation route.
A means for generating a pressure for the liquid to circulate in the circulation path,
The degassing means for removing the gas in the liquid and
A degassing control means for controlling the circulation and degassing of the liquid is provided.
The liquid storage means includes a first tank and a second tank, and includes a first tank and a second tank.
The pressure at which the liquid circulates is the differential pressure between the first tank and the second tank.
The degassing control means is
After performing the first degassing operation for circulating the liquid in the first path, the control is performed by switching to the second path and performing the second degassing operation for circulating the liquid in the second path.
The second degassing operation is a device for discharging a liquid, which controls to start circulation of the liquid at a differential pressure lower than the differential pressure in the first degassing operation. A liquid storage means for storing liquid and
The circulation path through which the liquid of the liquid storage means circulates,
The liquid discharge head provided in the circulation path and
A bypass path connecting the upstream and downstream of the liquid discharge head in the circulation path,
A first path in which the bypass path becomes a part of the circulation path and the liquid discharge head deviates from the circulation path, and a first path in which the liquid discharge head becomes a part of the circulation path and the bypass path deviates from the circulation path. Means to switch between 2 routes and
A means for generating a pressure for the liquid to circulate in the circulation path,
The degassing means for removing the gas in the liquid and
A degassing control means for controlling the circulation and degassing of the liquid is provided.
The liquid storage means includes a first tank and a second tank, and includes a first tank and a second tank.
The pressure at which the liquid circulates is the differential pressure between the first tank and the second tank.
The degassing control means is
After performing the first degassing operation for circulating the liquid in the first path, the control is performed by switching to the second path and performing the second degassing operation for circulating the liquid in the second path.
The second degassing operation is a device for discharging a liquid, which controls to start circulation of the liquid at a differential pressure lower than the differential pressure in the first degassing operation. The first tank is arranged on the upstream side of the liquid discharge head in the circulation path, the second tank is arranged on the downstream side of the liquid discharge head in the circulation path, and the second tank is from the first tank. Is also located on the upstream side where the liquid circulates.
The device for discharging a liquid according to claim 1 or 2. The device for discharging a liquid according to any one of claims 1 to 3, wherein in the second degassing operation, control for continuously or stepwisely increasing the differential pressure is performed . Claims 1 to 4, wherein when the second degassing operation is started, the first path and the second path are both closed and then the second path is opened . A device that discharges the liquid according to any one. The first manifold leading to the supply port side of multiple liquid discharge heads,
A second manifold leading to the discharge port side of the plurality of liquid discharge heads is provided.
The device for discharging a liquid according to any one of claims 1 to 5 , wherein the bypass path is a path connecting the first manifold and the second manifold . The first manifold leading to the supply port side of multiple liquid discharge heads,
A second manifold leading to the discharge port side of the plurality of liquid discharge heads is provided.
The bypass path is according to any one of claims 1 to 5 , wherein the bypass path is a path connecting the liquid path on the upstream side of the first manifold and the liquid path on the downstream side of the second manifold. A device that discharges the described liquid. The seventh aspect of the present invention is characterized in that the valve means capable of controlling the opening and closing of the liquid path on the downstream side of the second manifold and on the upstream side of the connection point with the bypass path is provided. A device that discharges the liquid. A first valve means for opening and closing a liquid path downstream from a connection point with the bypass path on the upstream side of the first manifold.
A second valve means for opening and closing a liquid path upstream of the connection point with the bypass path on the downstream side of the second manifold is provided.
When switching from the first path to the second path, the second valve means is opened before the first valve means.
The device for discharging a liquid according to claim 7.

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