JP6980339B2 - Liquid material discharge device and liquid material discharge method - Google Patents

Description

The present invention relates to a liquid material discharge device for discharging liquid from a discharge port and a liquid material discharge method.

Patent Document 1 below discloses an ink supply system that circulates and supplies ink from a sub tank to an inkjet head via an ink circulation path. In this ink supply system, pressure sensors are arranged on the upstream side and the downstream side of the inkjet head, respectively. The controller calculates the ink pressure at the position of the nozzle of the inkjet head based on the detection value of the pressure sensor, and controls the pressure in the sub tank so that the pressure becomes a predetermined value.

Japanese Unexamined Patent Publication No. 2015-157362

In some cases, it is desired to control not only the ink pressure at the nozzle position (ink pressure in the nozzle) but also the flow rate of ink flowing through the inkjet head. For example, when adopting a configuration in which the ink is heated and circulated, it is preferable to keep the flow rate of the ink constant in order to keep the temperature of the ink constant. As described above, it has been found that when a control system having two degrees of freedom and two physical quantities to be controlled is configured, a new problem arises in which the start-up time of the device becomes long.

An object of the present invention is to provide a liquid material discharge device and a liquid material discharge method capable of suppressing an increase in the start-up time of the device.

According to one aspect of the invention
A discharge port including a supply port to which the liquid material is supplied, a discharge port for discharging the liquid material supplied from the supply port, and a discharge port for discharging the liquid material that has not been discharged.
The first controlled amount, which is the meniscus pressure of the liquid material in the discharge port, and the second controlled amount, which is the differential pressure between the pressure of the supply port and the pressure of the discharge port, are the target values of the first controlled amount, respectively. It is provided with a constant first target value, and a control device for controlling so as to be maintained at a constant second target value, which is the target value of the second control amount.
The control device supplies the liquid material from the supply port to the discharge unit during the period until the first control amount and the second control amount approach the first target value and the second target value, respectively. Then, while discharging the liquid material from the discharge port, the control for bringing the first controlled amount closer to the first target value is executed in preference to the control for bringing the second controlled amount closer to the second target value. A functional liquid material discharge device is provided.

According to another aspect of the invention
Supply of the liquid material to a discharge portion including a supply port to which the liquid material is supplied, a discharge port for discharging the liquid material supplied from the supply port, and a discharge port for discharging the liquid material which has not been discharged. And discharge
The first controlled amount, which is the meniscus pressure of the liquid material in the discharge port, and the second controlled amount, which is the differential pressure between the pressure of the supply port and the pressure of the discharge port, are the target values of the first controlled amount, respectively. a control by constant first target value, and so as to maintain the second target value of the constant is a target value of the second control amount, a first control mode for supplying and discharging of the liquid material is ,
Prior to the control by the first control mode, the liquid material is supplied from the supply port to the discharge portion, and the liquid material is discharged from the discharge port, and the first control amount is set to the first target value. Provided is a liquid material discharge method for performing control by a second control mode in which the control of approaching to is executed in preference to the control of bringing the second controlled amount closer to the second target value.

The time for bringing the first control amount and the second control amount closer to the first target value and the second target value, respectively, becomes shorter. As a result, it is possible to suppress an increase in the start-up time of the device.

FIG. 1 is a schematic view of a liquid material discharge device according to an embodiment. FIG. 2 is a schematic control block diagram of a control system that controls the meniscus pressure Pma and the differential pressure Pda. FIG. 3 is a graph showing an example of time changes of the meniscus pressure Pma and the differential pressure Pda when the control is performed by the control method shown in FIG. FIG. 4 is a flowchart of the liquid material discharge method according to the embodiment. FIG. 5 is a control block diagram showing an example of the control executed in step S1. FIG. 6 is a control block diagram showing an example of the control executed in step S3. FIG. 7 is a graph showing an example of time changes of the meniscus pressure Pma and the differential pressure Pda when the meniscus pressure Pma and the differential pressure Pda are set by using the liquid material discharge method according to the embodiment.

A liquid material discharge device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7.
FIG. 1 is a schematic view of a liquid material discharge device according to an embodiment. Ink, which is a liquid material, is stored in the sub tank 20. A heater 35 is arranged in the sub tank 20, and the heater 35 heats the ink in the sub tank 20.

The ink in the sub tank 20 is supplied to the supply port 11 of the inkjet head (discharge unit) 10 through the supply path 51. An ink chamber from the supply port 11 to the discharge port 12 is provided in the inkjet head 10. The inkjet head 10 ejects ink in the ink chamber as droplets from a plurality of ejection ports (nozzles) 13. The ejection control device 31 controls the ejection of ink from the inkjet head 10.

The ink supplied to the inkjet head 10 and not ejected from the ejection port 13 is ejected from the ejection port 12. The ink discharged from the discharge port 12 is collected in the sub tank 20 through the collection path 52.

The first pump 21 is inserted in the supply path 51. The first pump 21 sends out the ink in the sub tank 20 toward the supply port 11 of the inkjet head 10. The first buffer tank 22 is inserted in the supply path 51 between the first pump 21 and the inkjet head 10. The first buffer tank 22 suppresses the pulsation of the ink delivered from the first pump 21.

A first pressure sensor 23 is attached to a supply path 51 between the first buffer tank 22 and the supply port 11. The first pressure sensor 23 measures the pressure of the ink flowing into the supply port 11 and obtains the measured value Psa.

A second pump 24 is inserted in the recovery path 52. The second pump 24 discharges ink from the inkjet head 10 through the discharge port 12 and sends it toward the sub tank 20. The second buffer tank 25 is inserted in the recovery path 52 between the second pump 24 and the inkjet head 10. The second buffer tank 25 suppresses the pulsation of the ink sucked by the second pump 24.

A second pressure sensor 26 is attached to a recovery path 52 between the second buffer tank 25 and the discharge port 12. The second pressure sensor 26 measures the pressure of the ink discharged from the discharge port 12 and obtains the measured value Pra.

When the amount of ink in the sub tank 20 decreases, the ink is replenished from the main tank 40 to the sub tank 20. A drain pipe 55 is provided in the sub tank 20. When cleaning the ink path of the liquid material ejection device, ink is discharged from the sub tank 20 through the drain pipe 55.

The controller (control device) 30 controls the outputs of the first pump 21 and the second pump 24 based on the measured values Psa and Pra of the first pressure sensor 23 and the second pressure sensor 26. The controller 30 can be realized by, for example, a programmable logic controller (PLC). In order to stably eject ink from the ejection port 13, the ink meniscus pressure at the position of the ejection port 13 (the pressure of the ink at the ejection port 13 when the ink meniscus is formed in the ejection port 13) is appropriate. It is preferable to control to a negative pressure (pressure below atmospheric pressure). Further, in order to keep the temperature of the circulating ink constant, it is preferable to control the flow rate of the ink within an appropriate range.

The meniscus pressure is from the measured value Psa of the first pressure sensor 23, the measured value Pra of the second pressure sensor 26, the flow path resistance Rs from the mounting position of the first pressure sensor 23 to the supply port 11, and the discharge port 12. It depends on the flow path resistance Rr to the mounting position of the second pressure sensor 26 and the head pressure Ph based on the height H from the discharge port 13 to the liquid surface of the ink in the sub tank 20. For example, the meniscus pressure Pma can be expressed by the following equation.
Pma = (Rr / (Rs + Rr)) Psa + (Rs / (Rs + Rr)) Pra + Ph ・ ・ ・ (1)

The flow rate of ink circulating in the sub tank 20, the supply path 51, the inkjet head 10, and the recovery path 52 depends on the difference between the measured value Psa of the first pressure sensor 23 and the measured value Pra of the second pressure sensor 26. .. Hereinafter, Psa-Pra is simply referred to as differential pressure Pda.

In order to maintain the temperature of the circulating ink at the target value and stably eject the ink, the meniscus pressure Pma and the flow rate of the ink may be maintained at the target values, respectively. In this embodiment, the meniscus pressure Pma (first control amount) and the differential pressure Pda (second control amount) are the meniscus pressure targets, respectively, with the meniscus pressure Pma as the first control amount and the differential pressure Pda as the second control amount. Control is performed so that the value Pmc (first target value) and the differential pressure target value Pdc (second target value) are maintained. This control can be performed, for example, by controlling the outputs of the first pump 21 and the second pump 24.

FIG. 2 is a schematic control block diagram of a control system that controls the meniscus pressure Pma and the differential pressure Pda. In FIG. 2, the display of functions such as gain, time delay, low-pass filter, and averaging filter is omitted. The deviation Pme between the meniscus pressure target value Pmc and the meniscus pressure Pma is input to the PID control block, and the meniscus pressure manipulated variable Pmo is output. The deviation Pde between the differential pressure target value Pdc and the differential pressure Pda is input to another PID control block, and the differential pressure operation amount Pdo is output.

The first pump command value Psc is determined based on the non-reversing value of the meniscus pressure manipulated variable Pmo and the non-reversing value of the differential pressure manipulated variable Pdo. The output of the first pump 21 is controlled by the first pump command value Psc. The second pump command value Prc is determined based on the reversal value of the meniscus pressure manipulated variable Pmo and the non-reversal value of the differential pressure manipulated variable Pdo. The output of the second pump 24 is controlled by the second pump command value Prc.

The meniscus pressure calculation block 61 outputs the meniscus pressure Pma based on the measured value Psa of the first pressure sensor 23, the measured value Pra of the second pressure sensor 26, and the head pressure Ph. For the derivation of the meniscus pressure Pma, for example, the above equation (1) may be used. The differential pressure calculation block 62 outputs the differential pressure Pda based on the measured value Psa of the first pressure sensor 23 and the measured value Pra of the second pressure sensor 26. For example, the differential pressure Pda may be calculated by the following formula.
Pda = Psa-Pra ・ ・ ・ (2)

When the meniscus pressure Pma becomes smaller than the meniscus pressure target value Pmc, the output in the direction of increasing the output of the first pump 21 and decreasing the output of the second pump 24 is controlled. As a result, the meniscus pressure Pma increases. When the meniscus pressure Pma becomes larger than the meniscus pressure target value Pmc, the reverse control is performed, and as a result, the meniscus pressure Pma decreases.

When the differential pressure Pda becomes smaller than the differential pressure target value Pdc, control is performed to increase the outputs of both the first pump 21 and the second pump 24. As a result, the differential pressure Pda becomes large. When the differential pressure Pda becomes larger than the differential pressure target value Pdc, the reverse control is performed, and as a result, the differential pressure Pda becomes smaller.

Next, before explaining the liquid material discharge method according to the embodiment, the problems in the period until the meniscus pressure Pma and the differential pressure Pda are set to the meniscus pressure target value Pmc and the differential pressure target value Pdc, respectively, will be described. This problem is newly discovered by the inventor of the present application by actually operating the liquid material discharge device. Here, "setting" means that the controlled amount of the meniscus pressure Pma, the differential pressure Pda, or the like is within the target range including the target value.

In the control block diagram shown in FIG. 2, the second pump command value Prc is set based on the difference between the differential pressure manipulated variable Pdo and the meniscus pressure manipulated variable Pmo. Therefore, depending on the initial state immediately after the start of control or the state during setting, the differential pressure operation amount Pdo and the meniscus pressure operation amount Pmo cancel each other out, and the second pump command value Prc may become minute. .. Therefore, the time required for the meniscus pressure Pma and the differential pressure Pda to be set may become long.

FIG. 3 is a graph showing an example of time changes of the meniscus pressure Pma and the differential pressure Pda when the control is performed by the control method shown in FIG. The horizontal axis represents the elapsed time, and the vertical axis represents the pressure in arbitrary units. The thick solid line and the thin solid line in FIG. 3 show the time change of the meniscus pressure Pma and the differential pressure Pda, respectively.

When the control is started at time 0, the meniscus pressure Pma and the differential pressure Pda gradually approach the meniscus pressure target value Pmc and the differential pressure target value Pdc, respectively. Here, the meniscus pressure target value Pmc becomes negative at the gauge pressure. With this method, it took about 1500 seconds from the start of control to the completion of settling. Therefore, it is necessary to wait at least 1500 seconds from the start-up of the device to the ink ejection operation. In the embodiment described below, the settling time can be shortened.

FIG. 4 is a flowchart of the liquid material discharge method according to the embodiment. Each process of this flowchart is executed by the controller 30 (FIG. 1). When the control is started, first, the meniscus pressure Pma is controlled to approach the meniscus pressure target value Pmc without controlling the differential pressure Pda to approach the differential pressure target value Pdc (step S1). For example, control is performed to set the meniscus pressure Pma within the target range including the meniscus pressure target value Pmc. The control mode in step S1 is referred to as a "meniscus pressure setting mode". That is, the control for bringing the meniscus pressure Pma closer to the meniscus pressure target value Pmc is performed prior to the control of the differential pressure Pda.

FIG. 5 is a control block diagram showing an example of control of the meniscus setting mode. The differential pressure manipulated variable Pdo is not used to control either the first pump 21 or the second pump 24. Therefore, the control to bring the differential pressure Pda closer to the differential pressure target value Pdc is not performed. The second pump command value Prc for the second pump 24 is determined based on the reversal value of the meniscus pressure manipulated variable Pmo.

The first pump command value Psc is fixed to the command value PscL that operates the first pump 21 at the output lower limit value. As a result, the first pump 21 is driven at the lower limit of the output. Since the meniscus pressure manipulated variable Pmo is fed back to the output control of the second pump 24, this control causes the meniscus pressure Pma to approach the meniscus pressure target value Pmc.

The controller 30 determines whether or not the meniscus pressure Pma approaches the meniscus pressure target value Pmc (step S2). If the meniscus pressure Pma is set within the target range including the meniscus pressure target value Pmc, step S3 is executed. This target range may be wider than the target range for adjusting the meniscus pressure Pma when discharging the liquid material. In step S3, control is performed to bring the differential pressure Pda closer to the differential pressure target value Pdc while preventing the meniscus pressure Pma from diverging. For example, control is performed to set the differential pressure Pda within the target range including the differential pressure target value Pdc. The control mode in step S3 is referred to as a "differential pressure setting mode".

FIG. 6 is a control block diagram showing an example of control of the differential pressure setting mode. The first pump command value Psc is determined based on the non-inverted value of the differential pressure manipulated variable Pdo. This control acts in the direction of increasing the output of the first pump 21 when the differential pressure Pda becomes smaller than the differential pressure target value Pdc, and the output of the first pump 21 when the differential pressure Pda becomes larger than the differential pressure target value Pdc. Acts in the direction of lowering.

The second pump command value Prc is determined based on the value obtained by reversing the meniscus pressure manipulated variable Pmo and the value obtained by reversing the differential pressure manipulated variable Pdo. The reason why the value obtained by reversing the meniscus pressure manipulated variable Pmo is used for the feedback control is to prevent the meniscus pressure Pma that has approached the meniscus pressure target value Pmc in step S1 (FIG. 4) from being dissipated. Further, in the control in the steady state shown in FIG. 2, the second pump command value Prc was determined based on the non-inverted value of the differential pressure manipulated variable Pdo. The reason why the differential pressure manipulated variable Pdo is reversed in step S3 is to prevent the meniscus pressure manipulated variable Pmo and the differential pressure manipulated variable Pdo from canceling each other out.

This control acts in the direction of increasing the output of the first pump 21 and decreasing the output of the second pump 24 when the differential pressure Pda becomes smaller than the differential pressure target value Pdc. When the differential pressure Pda becomes larger than the differential pressure target value Pdc, the output of the first pump 21 is decreased and the output of the second pump 24 is increased.

When the differential pressure Pda is smaller than the differential pressure target value Pdc, the control for increasing the output of the first pump 21 acts in the direction of increasing the differential pressure Pda, but the control for decreasing the output of the second pump 24. On the contrary, acts in the direction of reducing the differential pressure Pda. Therefore, when the magnitude acting in the direction of increasing the differential pressure Pda and the magnitude acting in the direction of decreasing the differential pressure Pda are balanced, it seems that the differential pressure Pda does not approach the differential pressure target value Pdc.

Next, the reason why the differential pressure Pda approaches the differential pressure target value Pdc by the above control will be described. When the control mode is the differential pressure setting mode, the meniscus pressure manipulated variable Pmo is connected only to the second pump 24 as shown in FIG. Due to the effect of the increase in the output of the first pump 21 due to the differential pressure operation amount Pdo, the output of the second pump 24 increases due to the meniscus pressure operation amount Pmo, and the pressure of the ink discharged from the discharge port 12 decreases. As a result, the balance of the differential pressure Pda is lost, and the differential pressure Pda approaches the differential pressure target value Pdc.

The controller 30 determines whether or not the differential pressure Pda approaches the differential pressure target value Pdc (step S4). If the differential pressure Pda is set within the target range including the differential pressure target value Pdc, step S5 is executed. This target range may be wider than the target range for adjusting the differential pressure Pda when discharging the liquid material. In step S5, both the meniscus pressure Pma and the differential pressure Pda are controlled to be maintained at the meniscus pressure target value Pmc and the differential pressure target value Pdc, respectively. In step S5, control is performed by the control block diagram shown in FIG. The control mode in step S5 is referred to as a "precision settling mode".

The liquid material is discharged with the meniscus pressure Pma and the differential pressure Pda within the settling target width. During the discharge of the liquid material, the control of the precision settling mode is continuously executed. When the discharge process is terminated, this control is terminated (step S6).

Next, with reference to FIG. 7, the excellent effect of the liquid material discharge method according to the above embodiment will be described.

FIG. 7 is a graph showing an example of time changes of the meniscus pressure Pma and the differential pressure Pda when the meniscus pressure Pma and the differential pressure Pda are set by using the liquid material discharge method according to the embodiment. The horizontal axis represents the elapsed time, and the vertical axis represents the pressure in arbitrary units. The thick solid line and the thin solid line in FIG. 3 show the time change of the meniscus pressure Pma and the differential pressure Pda, respectively.

The periods T1, T2, and T3 of FIG. 7 correspond to the control periods of the meniscus pressure setting mode (step S1), the differential pressure setting mode (step S3), and the precision setting mode (step S5) of FIG. 4, respectively. In the period T1, since the meniscus pressure Pma is controlled, the meniscus pressure Pma approaches the meniscus pressure target value Pmc. However, since the differential pressure Pda is not controlled, the differential pressure Pda hardly approaches the differential pressure target value Pdc. Since the differential pressure Pda is controlled in the period T2, the differential pressure Pda approaches the differential pressure target value Pdc faster than in the period T1. The meniscus pressure Pma once changes in the direction away from the meniscus pressure target value Pmc, but does not diverge and gradually approaches the meniscus pressure target value Pmc.

In the period T3, the meniscus pressure Pma and the differential pressure Pda once deviate from the meniscus pressure target value Pmc and the differential pressure target value Pdc, but after that, the meniscus pressure target value Pmc and the differential pressure target value Pdc are reached. It is approaching rapidly. Both the meniscus pressure Pma and the differential pressure Pda were settled about 90 seconds after the start of control.

When the controls of steps S2 and S4 (FIG. 4) were not performed, for example, it took about 1500 seconds to settle as shown in FIG. On the other hand, in the method according to the example, the time required for setting was shortened to, for example, 90 seconds. This makes it possible to improve the operating rate of the liquid material discharge device. Further, since the heating time of the ink is shortened, an energy saving effect can be obtained.

In the above embodiment, in step S1 (FIG. 4), the meniscus pressure Pma is controlled by operating the first pump 21 at the lower limit of the output and changing the output of the second pump 24. Since the first pump 21 operates at the lower limit of the output, the meniscus pressure Pma can be quickly reduced to a negative pressure by making the output of the second pump 24 slightly larger than the lower limit of the output.

On the other hand, in the example shown in FIG. 3, the time from the start of control until the meniscus pressure Pma becomes a negative pressure is about 750 seconds. Until the meniscus pressure Pma becomes a negative pressure, ink dripping from the ejection port 13 of the inkjet head 10 is likely to occur. In the method according to the above embodiment, the meniscus pressure Pma can be reduced to a negative pressure in a short time, so that ink dripping from the ejection port 13 of the inkjet head 10 is unlikely to occur.

In the above embodiment, feedback control was performed using the meniscus pressure Pma defined in the equation (1) as the first controlled variable and the differential pressure Pda defined in the equation (2) as the second controlled variable. As another configuration, the physical quantity that depends on the meniscus pressure Pma itself instead of the meniscus pressure Pma itself may be used as the first controlled quantity, and the physical quantity that depends on the differential pressure Pda may be used as the second controlled quantity. For example, when the head pressure Ph shown in the equation (1) is constant, the sum of the first term and the second term on the right side of the equation (1) may be used as the first control amount. Further, when the flow path resistance Rs and the flow path resistance Rr are equal, the meniscus pressure Pma is expressed by the following equation.
Pma = (Psa + Pra) / 2 + Ph ・ ・ ・ (3)

Therefore, when the head pressure Ph is constant, Psa + Pra may be used as the first control amount. In particular, the physical quantity that depends on the meniscus pressure Pma and has a one-to-one correspondence with the meniscus pressure may be the first controlled quantity. Similarly, a physical quantity that depends on the differential pressure Pda and has a one-to-one correspondence with the differential pressure Pda may be used as the second control quantity.

Next, a modification of the above embodiment will be described.
In the above embodiment, in the meniscus setting mode (step S1), the first pump 21 is operated at the lower limit of the output, and the output of the second pump 24 is changed. As another method, for example, the second pump 24 may be operated at the output upper limit value to change the output of the first pump 21.

In the above embodiment, the control of the meniscus pressure Pma is prioritized in terms of time over the control of the differential pressure Pda, and the meniscus pressure Pma is controlled before the control of the differential pressure Pda. Instead of the configuration giving priority in terms of time, the control of the meniscus pressure Pma may be prioritized by making the feedback amount of the meniscus pressure Pma larger than the feedback amount of the differential pressure Pda. Also in this case, in the initial stage from the control start time, a period in which the speed at which the meniscus pressure Pma approaches the meniscus pressure target value Pmc becomes faster than the speed at which the differential pressure Pda approaches the differential pressure target value Pdc appears.

In the above embodiment, the meniscus pressure Pma and the differential pressure Pda were controlled by changing the outputs of the two pumps. Instead of varying the outputs of the two pumps, at least two manipulated variables that affect the meniscus pressure Pma and the differential pressure Pda may be varied. As the operation amount to be changed, any two of the output of the pump, the flow path resistance, the pressure in the sub tank 20, and the like can be selected.

The above examples are examples, and the present invention is not limited to the above examples. For example, it will be obvious to those skilled in the art that various changes, improvements, combinations, etc. are possible.

10 Inkjet head (discharge part)
11 Supply port 12 Discharge port 13 Discharge port 20 Sub tank 21 First pump 22 First buffer tank 23 First pressure sensor 24 Second pump 25 Second pump tank 26 Second pressure sensor 30 Controller (control device) )
31 Discharge control device 35 Heater 40 Main tank 51 Supply path 52 Recovery path 55 Drain pipe 61 Meniscus pressure calculation block 62 Differential pressure calculation block

Claims (8)

A discharge port including a supply port to which the liquid material is supplied, a discharge port for discharging the liquid material supplied from the supply port, and a discharge port for discharging the liquid material that has not been discharged.
The first controlled amount, which is the meniscus pressure of the liquid material in the discharge port, and the second controlled amount, which is the differential pressure between the pressure of the supply port and the pressure of the discharge port, are the target values of the first controlled amount, respectively. It is provided with a constant first target value, and a control device for controlling so as to be maintained at a constant second target value, which is the target value of the second control amount.
The control device supplies the liquid material from the supply port to the discharge unit during the period until the first control amount and the second control amount approach the first target value and the second target value, respectively. Then, while discharging the liquid material from the discharge port, the control for bringing the first controlled amount closer to the first target value is executed in preference to the control for bringing the second controlled amount closer to the second target value. Liquid material discharge device with function. The control device is
Control is performed to set the first control amount within the first target range including the first target value.
After that, control is performed to set the second control amount within the second target range including the second target value.
The liquid material discharge device according to claim 1, wherein the control is performed to maintain the first control amount and the second control amount at the first target value and the second target value. Moreover,
A first pressure sensor that measures the pressure of the liquid material flowing into the supply port, and
It has a second pressure sensor that measures the pressure of the liquid material discharged from the outlet.
The liquid material discharge device according to claim 1 or 2, wherein the control device obtains the second control amount based on the difference between the measured value of the first pressure sensor and the measured value of the second pressure sensor. The control device is based on the sum of the measured value of the first pressure sensor and the measured value of the second pressure sensor, and the water head pressure applied to the liquid material at the position of the discharge port, and the first control is performed. The liquid material discharge device according to claim 3, wherein the amount is obtained. Moreover,
A first pump that pumps the liquid material toward the supply port,
It has a second pump that discharges the liquid material from the outlet.
By controlling the outputs of the first pump and the second pump, the control device changes the first control amount and the second control amount into the first target value and the second target value, respectively. The liquid material discharge device according to any one of claims 1 to 3 to be brought closer. The control device performs the control for bringing the first control amount closer to the first target value in preference to the control for bringing the second control amount closer to the second target value, during the period when the first pump and the control device are executed. The liquid material discharge device according to claim 5, wherein one of the second pumps is operated at a constant output to change the output of the other pump. Supply of the liquid material to a discharge portion including a supply port to which the liquid material is supplied, a discharge port for discharging the liquid material supplied from the supply port, and a discharge port for discharging the liquid material which has not been discharged. And discharge
The first controlled amount, which is the meniscus pressure of the liquid material in the discharge port, and the second controlled amount, which is the differential pressure between the pressure of the supply port and the pressure of the discharge port, are the target values of the first controlled amount, respectively. a control by constant first target value, and so as to maintain the second target value of the constant is a target value of the second control amount, a first control mode for supplying and discharging of the liquid material is ,
Prior to the control by the first control mode, the liquid material is supplied from the supply port to the discharge portion, and the liquid material is discharged from the discharge port, and the first control amount is set to the first target value. A liquid material discharge method for performing control by a second control mode in which control to bring the second control amount closer to is executed in preference to control to bring the second control amount closer to the second target value. In the first control mode, the first control amount is set within the first target range including the first target value, and then the second control amount is set to the second target including the second target value. The liquid material discharge method according to claim 7, wherein the liquid material is set within the range.

Images