JP2009279847A - Ink jet device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact ink jet device. <P>SOLUTION: In the ink jet device 100, after only the inside of a reference pressure chamber 7 is brought into a decompressed state of a fixed level, the remaining capacities of sub-tanks 2A, 2B, and 2C in pressure chambers 6A, 6B, and 6C are calculated from changes in pressure in the reference pressure chamber 7 when the pressure chambers 6A, 6B, and 6C communicate with one another. If the calculated remaining capacities are equal to or greater than a fixed value, filling of the sub-tanks 2A, 2B, and 2C with ink is started and also inflows are monitored through pressure changes. The influx of the ink is stopped when the ink reaches a specific quantity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inkjet apparatus that applies a liquid material by an inkjet method. More specifically, the present invention relates to a liquid material filling mechanism from a main tank to a sub tank and a liquid material discharging mechanism to a waste liquid tank in the ink jet apparatus.

  An industrial inkjet device applies a liquid material to a discharge target by an inkjet method. Specifically, in the ink jet apparatus, after the liquid material in the main tank is filled into a sub tank that has been subjected to negative pressure control, the liquid material filled in the sub tank is ejected from the ink jet head onto an ejection target.

  On the other hand, in such an ink jet apparatus, waste liquid generated during maintenance operation of the ink jet head or the like is temporarily stored in a waste liquid tank.

  Conventionally, in such an ink jet apparatus, the inflow operation of the liquid material from the main tank to the sub tank and the inflow operation of the liquid material from the ink jet head to the waste liquid tank have been performed by a drive source such as a liquid feed pump. In such an ink jet apparatus, the storage amount of the liquid material in each tank has been detected by a weight sensor, a liquid level sensor, a capacitance sensor, a light amount sensor, or the like.

  For example, Patent Document 1 discloses a waste liquid system that transports waste liquid accumulated in a collection container to a vacuum transport pipe. Specifically, the waste liquid system of Patent Document 1 includes a sensor valve, a control valve, and a vacuum valve in addition to a collection container. Each valve is a differential pressure valve interlocked with each other, and the transport cycle of the waste liquid is controlled by the acting differential pressure.

  Patent Document 2 discloses a fuel remaining amount measuring device. Specifically, the fuel remaining amount measuring device of Patent Document 2 changes the volume of the space in the main tank and the reference tank, and determines the fuel remaining amount in the main tank based on the ratio of the pressure fluctuation values in both spaces. taking measurement. However, the remaining fuel amount measuring device of Patent Document 2 is different from the inkjet device in industrial application fields.

Patent Document 3 discloses an apparatus for measuring a void volume in a body to be measured. Specifically, the volume measuring device of Patent Document 3 is a configuration in which a measurement container in which a measurement object to be measured for void volume is accommodated is connected to a standard container, and measurement is performed from a pressure change caused by this connection. Determine the apparent volume of the container. That is, in the volume measuring device of Patent Document 3, since the volume of the measurement container is equal to the sum of the apparent volume of the measurement container and the volume of the measured object minus the volume of the gap, The void volume is determined.
No. 6-509988 (published on November 10, 1994) Japanese Patent Laid-Open No. 6-300608 (released on October 28, 1994) JP-A-4-339221 (published on November 26, 1992)

  However, the conventional ink jet device has a problem that the size is increased, leading to an increase in cost.

  Specifically, in recent years, the size of products (for example, liquid crystal televisions) including an object to be ejected on which a liquid material is applied by an ink jet apparatus has been increasing. Due to this influence, an increase in the size of the discharge target (for example, a glass substrate) and an increase in the size of the inkjet apparatus itself are also progressing. Furthermore, the types of liquid materials used in ink jet devices are diversifying.

  When a plurality of types of liquid materials are used in the ink jet apparatus, a main tank and a sub tank independent from each other are provided for each of the plurality of types of liquid material. However, conventionally, in such a case, a liquid feed pump for filling the liquid material from each main tank to each sub tank and a liquid amount sensor for detecting the liquid amount in each sub tank are provided for each liquid material. Mounted (individually). As a result, there is a problem that the liquid material feeding system (supply system) becomes complicated and large.

  Such a problem also occurs in the case of a waste liquid system in an inkjet apparatus. That is, this waste liquid system is composed of a waste liquid tank and an inflow system for allowing the waste liquid to flow into the waste liquid tank. In the case of an inkjet apparatus that uses a single liquid material or a plurality of liquid materials having compositions similar to each other, the waste liquid system may be a single configuration regardless of the type of liquid material.

  However, the production process of the above products is only increasing in complexity. That is, in most cases, a plurality of liquid materials that cannot be mixed with each other are used. In other words, it is extremely rare when the waste liquid system may have a single configuration. For this reason, also in a waste liquid system, it mounts for every liquid material (individually). As a result, there arises a problem that the waste liquid system becomes complicated and large.

  In particular, a large-sized ink jet apparatus is required to perform application of a liquid material from an ink jet head to a discharge target and supply of the liquid material to the ink jet head with high speed and high accuracy. However, as described above, when the liquid feeding system and the waste liquid system become complicated, this requirement cannot be satisfied.

  In addition, Patent Documents 1 to 3 do not have a description suggesting application to an ink jet apparatus, and the industrial application field is also different from that of an ink jet apparatus.

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to realize a small-sized ink jet apparatus by simplifying a liquid feeding system and a waste liquid system.

In order to solve the above problems, an inkjet apparatus of the present invention is an inkjet apparatus that discharges a plurality of types of liquid materials,
A main tank and a sub tank provided independently for each liquid material;
An ink jet head for supplying the liquid material of the sub tank filled from the main tank and discharging the supplied liquid material;
A pressure chamber for sealing each sub tank and applying pressure to the sub tank;
A reference pressure chamber that is communicated with each pressure chamber and in which the internal pressure varies;
A pump for adjusting the pressure in the reference pressure chamber;
A pressure sensor for detecting the pressure in the reference pressure chamber;
A shut-off section for switching each pressure chamber and the reference pressure chamber to a communication state or a shut-off state;
A control unit for controlling the driving of the pump and the opening / closing operation of the blocking unit;
The control unit
After the shut-off portion is in the open state, the pressure in each pressure chamber and the pressure in the reference pressure chamber are equalized, then the shut-off portion is in the closed state, and the pressure value of the reference pressure chamber when the reference pressure chamber is held at a negative pressure, From the amount of change from the pressure value of the reference pressure chamber when the blocking portion is opened with the reference pressure chamber held at the negative pressure, the volume in the sub tank is calculated,
Based on the calculated internal volume of the subtank, it is determined whether or not it is necessary to fill the subtank with the liquid material from the main tank.

  According to the above invention, the pressure chamber and the reference pressure chamber communicate with each other. In addition, the pressure chamber and the reference pressure chamber can be communicated or blocked by the blocking unit. Further, the pressure in the reference pressure chamber can be adjusted by driving the pump.

  Thus, when the blocking part is opened, the pressure in each pressure chamber and the pressure in the reference pressure chamber are equal to each other. On the other hand, when the pump is driven with the pressure chamber and the reference pressure chamber shut off, only the reference pressure chamber can be decompressed. Further, when the pump is driven with the pressure chamber and the reference pressure chamber in communication with each other, the pressure chamber can be decompressed in addition to the reference pressure chamber. Note that the pressure in the reference pressure chamber can be detected by a pressure sensor.

  Here, after the pressure chamber and the reference pressure chamber are shut off and only the reference pressure chamber is brought into a constant reduced pressure state, when the pressure chamber communicates with the reference pressure chamber, the reduced pressure state in the reference pressure chamber changes. In the above invention, the volume in the sub tank is calculated from such a pressure change. Then, based on the calculated inner volume of the sub tank, it is determined whether or not it is necessary to fill the liquid material from the main tank to the sub tank. That is, when the calculated internal volume of the sub tank is equal to or less than the set value (predetermined value), the liquid material from the main tank to the sub tank is filled.

  As described above, according to the above invention, the volume (remaining volume) in the sub tank provided independently for each liquid material is calculated from the detection value of the pressure sensor that detects the pressure in the reference pressure chamber. . Further, the pressure in the pressure chamber is adjusted by a pump for adjusting the pressure in the reference pressure chamber and a shut-off unit. For this reason, it is not necessary to provide a pump and a pressure sensor in each pressure chamber. Thereby, the structure of the liquid feeding system (filling system) in an inkjet apparatus can be simplified. Accordingly, it is possible to reduce the size of the ink jet apparatus.

  In the ink jet apparatus of the present invention, it is preferable that the control unit controls the pressure on each sub tank so that the filling speed of each liquid material from the main tank to the sub tank is constant.

  The viscosity and the resistance to the flow path from the main tank to the sub-tank vary depending on the liquid material. For this reason, regardless of the type of liquid material, when a certain pressure is applied to the sub tank, the filling speed (inflow speed) to the sub tank differs.

  According to the above invention, when liquid material is required from the main tank to the sub tank, the pressure on the sub tank is controlled so that the filling speed of the liquid material from the main tank to the sub tank is constant. That is, a pressure corresponding to the characteristics of the liquid material is applied to the sub tank. Therefore, it is possible to fill the sub tank with the liquid material under appropriate conditions.

  In the ink jet apparatus according to the present invention, when the liquid material is not filled from the main tank to the sub tank, the control unit causes the pressure chamber and the reference pressure chamber to communicate with each other and drives the pump to place the sub tank in a negative pressure state. It is preferable.

  According to the above invention, even when the liquid material is not filled from the main tank to the sub tank, the pump is driven and the sub tank is in a negative pressure state. Thereby, it is possible to prevent the liquid material from leaking from the inkjet head.

  Moreover, according to said invention, the pump which adjusts the pressure in a reference | standard pressure chamber is combined as a pump for preventing the leakage of a liquid material. For this reason, it is not necessary to separately provide a pump for preventing leakage of the liquid material. Therefore, the ink jet device can be further reduced in size.

  In the ink jet apparatus of the present invention, it is preferable that the control unit causes the pressure chamber and the reference pressure chamber to communicate with each other when the ink is ejected from the ink jet head to drive the pump so that the sub tank is in a negative pressure state. .

  According to the above invention, when the ink is ejected from the inkjet head, the pump is driven and the sub tank is in a negative pressure state. That is, the pump that adjusts the pressure in the reference pressure chamber is also used as a pump for discharging ink. For this reason, it is not necessary to separately provide a pump for discharging ink. Therefore, the ink jet device can be further reduced in size.

In the ink jet device of the present invention, the ink jet device further includes an opening for opening the reference pressure chamber and each pressure chamber to the atmosphere,
The control unit keeps the reference pressure chamber at a negative pressure by opening the open portion and the shut-off portion and setting each pressure chamber and the reference pressure chamber to atmospheric pressure and then closing the open portion and the shut-off portion. The volume in the sub-tank is calculated from the amount of change between the pressure value of the reference pressure chamber and the pressure value of the reference pressure chamber when the shut-off portion is opened with the reference pressure chamber held at the above negative pressure. It is preferable to do.

  According to the above invention, the volume in the sub-tank is calculated after the open portion and the shut-off portion are in the open state and the pressure chambers and the reference pressure chamber are at atmospheric pressure. For this reason, it is not necessary to drive the pump in order to equalize the pressure in each pressure chamber and the reference pressure chamber. Therefore, the process for calculating the volume in the sub tank can be simplified.

  The ink jet apparatus of the present invention preferably includes a pair of pumps and a pressure sensor.

  According to the above invention, regardless of the type of liquid material, the set of pumps and pressure sensors allows at least the filling of the liquid material, the filling speed of the liquid material, the prevention of leakage of the liquid material from the inkjet head, and the ink ejection. Do one. Thereby, the apparatus structure of an inkjet apparatus can be simplified. Therefore, further downsizing of the ink jet apparatus can be realized.

In the ink jet device of the present invention, a plurality of waste liquid tanks for storing liquid materials that are not discharged from the ink jet head,
Each waste liquid tank is sealed, a waste liquid pressure chamber for applying pressure to the waste liquid tank,
A waste liquid reference pressure chamber that communicates with each waste liquid pressure chamber, and in which the internal pressure fluctuates,
A waste liquid pump for adjusting the pressure in the waste liquid reference pressure chamber;
Waste liquid pressure sensor for detecting the pressure in the waste liquid reference pressure chamber;
A waste liquid blocking section for switching each waste liquid pressure chamber and the waste liquid reference pressure chamber to a communication state or a blocking state;
It has a waste liquid control unit that controls the drive of the waste liquid pump and the opening and closing operation of the waste liquid blocking unit,
The waste liquid control unit
Waste liquid reference pressure when the waste liquid blocking chamber is opened and the pressure of each waste liquid pressure chamber is equalized with the pressure of the waste liquid reference pressure chamber, then the waste liquid blocking section is closed and the waste liquid reference pressure chamber is held at a negative pressure. The volume in the waste liquid tank is calculated from the amount of change between the pressure value in the chamber and the pressure value in the waste liquid reference pressure chamber when the waste liquid blocking section is opened with the waste liquid reference pressure chamber held at the above negative pressure. And
It is preferable to determine whether or not the liquid material can be discharged from the inkjet head to the waste liquid tank based on the calculated internal volume of the waste liquid tank.

  According to the above invention, the discharging operation from the ink jet head to the waste liquid tank is performed in the same manner as the filling of the liquid material from the main tank to the sub tank. That is, according to the above invention, the volume (remaining volume) in the waste liquid tank provided independently for each liquid material is calculated from the detection value of the waste liquid pressure sensor that detects the pressure in the waste liquid reference pressure chamber. Yes. The pressure in the waste liquid pressure chamber is adjusted by a waste liquid pump that adjusts the pressure in the waste liquid reference pressure chamber and a waste liquid blocking unit. For this reason, it is not necessary to provide a waste liquid pump or a waste liquid pressure sensor in each waste liquid pressure chamber. Thereby, the structure of the waste liquid system in an inkjet apparatus can be simplified. Accordingly, it is possible to reduce the size of the ink jet apparatus.

The inkjet apparatus of the present invention further includes a waste liquid release portion that opens the waste liquid reference pressure chamber to the atmosphere,
The waste liquid control unit opens the waste liquid opening part and the waste liquid blocking part and sets each waste liquid pressure chamber and the waste liquid reference pressure chamber to atmospheric pressure, and then closes the waste liquid opening part and the waste liquid blocking part to close the waste liquid standard. Pressure value of the waste liquid reference pressure chamber when the pressure chamber is held at negative pressure, and pressure value of the waste liquid reference pressure chamber when the waste liquid blocking part is opened with the waste liquid reference pressure chamber held at the above negative pressure It is preferable to calculate the volume in the waste liquid tank from the change amount.

  According to the above invention, the volume in the waste liquid tank is calculated after the waste liquid release section and the waste liquid blocking section are in the open state, and the respective waste liquid pressure chambers and the waste liquid reference pressure chamber are at atmospheric pressure. For this reason, it is not necessary to drive the pump in order to equalize the pressure in each pressure chamber and the reference pressure chamber. Therefore, the process for calculating the volume in the waste liquid tank can be simplified.

  The ink jet apparatus of the present invention preferably includes a pair of waste liquid pumps and a waste liquid pressure sensor.

  According to the above invention, the liquid material is discharged to the waste liquid tank by the set of waste liquid pump and the waste liquid pressure sensor regardless of the type of the liquid material. Thereby, the structure of the waste liquid system of an inkjet apparatus can be simplified more.

  As described above, according to the present invention, the control unit opens the blocking unit, equalizes each pressure in each pressure chamber and the reference pressure chamber, then closes the blocking unit, and sets the reference pressure chamber to a negative pressure. From the amount of change between the pressure value of the reference pressure chamber when held at a negative pressure and the pressure value of the reference pressure chamber when the blocking portion is opened with the reference pressure chamber held at the above negative pressure, The volume is calculated, and whether or not it is necessary to fill the liquid material from the main tank to the sub tank is determined based on the calculated inner volume of the sub tank. Therefore, the configuration of the liquid feeding system (filling system) in the ink jet apparatus can be simplified. Therefore, the ink jet apparatus can be reduced in size.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2. Note that the present invention is not limited to the configurations of the following embodiments.

[Embodiment 1]
FIG. 1 is a plan view showing a main configuration of an ink jet apparatus according to the present invention. In the present embodiment, as shown in FIG. 1, an inkjet apparatus 100 that ejects three types of ink (liquid material) will be described. Below, when distinguishing these three types of ink, A, B, and C are attached after each member, and when not distinguishing ink, it demonstrates without attaching A, B, and C.

  As shown in FIG. 1, the ink jet apparatus 100 includes main tanks 1A, 1B, 1C, sub tanks 2A, 2B, 2C, and ink jet heads 3A, 3B, 3C, which are provided independently for each ink. . The ink jet apparatus 100 discharges ink filled in the sub tanks 2A, 2B, 2C from the main tanks 1A, 1B, 1C from the ink jet heads 3A, 3B, 3C.

  The ink jet apparatus 100 also includes a pair of vacuum pumps 8 and pressure sensors 9 and a control unit 10 that controls the ink filling operation (filling amount) from the main tank 1 to the sub tank 2. Yes.

  Each of the main tank 1 and the sub tank 2 has a bag shape, and stores a liquid material such as ink. The main tanks 1A, 1B, 1C and the sub tanks 2A, 2B, 2C are connected to each other by independent flow paths 21A, 21B, 21C. Filling valves 4A, 4B, and 4C are provided in the flow paths 21A, 21B, and 21C, respectively. Accordingly, ink can be filled from the main tank 1 to the sub tank 2 by opening and closing the filling valve 4. The ink filling into the sub tank 2 is performed when a certain amount of ink in the sub tank 2 is consumed. Further, in the ink jet apparatus 100, the amount of ink used for ejection is extremely small, and the amount of waste ink from the ink jet head 3 during maintenance of the ink jet head 3 is much larger than that. For this reason, filling of the sub tank 2 with ink is often performed after maintenance (cleaning) of the inkjet head 3.

  On the other hand, the sub tanks 2A, 2B, 2C and the inkjet heads 3A, 3B, 3C are connected to each other by independent flow paths 22A, 22B, 22C. Supply valves 5A, 5B, and 5C are provided in the flow paths 22A, 22B, and 22C, respectively. Thus, ink can be supplied from the sub tank 2 to the inkjet head 3 by opening and closing the supply valve 5.

  The sub tanks 2A, 2B, 2C are provided in the pressure chambers 6A, 6B, 6C independent of each other. That is, the sub tank 2 is sealed in the pressure chamber 6. In FIG. 1, the pressure chambers 1A, 1B, and 1C are arranged adjacent to each other in this order. Further, a reference pressure chamber 7 is provided adjacent to and adjacent to the pressure chamber 6C of the sub tank 2C. Thus, the four pressure chambers (pressure chambers 6A, 6B, 6C and the reference pressure chamber 7) are arranged side by side. The main tank 1 is not provided in the pressure chamber 6 like the sub tank 2 and exists under atmospheric pressure.

  Unlike the pressure chamber 6 in which the sub tank 2 is accommodated, the reference pressure chamber 7 does not accommodate anything inside. A vacuum pump 8 and a pressure sensor 9 are connected to the reference pressure chamber 7. The vacuum pump 8 places the reference pressure chamber 7 in a reduced pressure state. The pressure sensor 9 detects the pressure in the reference pressure chamber 7. The pressure value detected by the pressure sensor 9 is output to the control unit 10. In the ink jet apparatus 100, the pressure and volume in each sub tank 6 </ b> A, 6 </ b> B, 6 </ b> C are calculated by the pair of vacuum pumps 8 and the pressure sensor 9. Such calculation is performed by the control unit 10. Then, the control unit 10 controls the vacuum pump 8 according to the calculation result.

  Specifically, the reference pressure chamber 7 and each of the sub tanks 6A, 6B, 6C are connected by a pipe 23. The piping 23 is branched into the pressure chambers 6A, 6B, and 6C, and the cutoff valves 11A, 11B, and 11C are formed in the piping 23 after the branching. The reference pressure chamber 7 includes an atmosphere release valve (open portion) 12. Thereby, the pressure in each pressure chamber 6A, 6B, 6C is controllable by operating each cutoff valve 11A, 11B, 11C and the air release valve 12. FIG. Further, the volume in the sub tank 6 can be calculated from the detection value of the pressure sensor 9.

  The inkjet head 3 is provided with a nozzle (not shown) at the tip, and discharges ink from this nozzle.

  Here, an ink ejection operation in the inkjet apparatus 100 will be described. In the ink jet apparatus 100, the ink ejection operation is controlled by the control unit 10.

  In order for the ink jet apparatus 100 to eject ink from the ink jet head 3, first, the specified amount sub tank 2 is filled with the ink in the main tank 1. Next, the ink filled in the sub tank 2 is supplied to the inkjet head 3.

  Specifically, the main tank 1 is disposed under atmospheric pressure. On the other hand, when the sub tank 2 is filled with ink, the internal pressure of the pressure chamber 6 is set to a negative pressure. In this state, the filling valve 4 is opened. As a result, the ink in the main tank 1 is filled into the sub tank 2 via the flow path 21. When the specified amount of ink is filled in the sub tank 2, the filling valve 4 is closed and the ink filling is finished.

  Next, the supply valve 5 is opened. As a result, the ink in the sub tank 2 is supplied to the inkjet head 3 via the flow path 22. Then, the supplied ink is ejected from the inkjet head 3. When ink is ejected, the internal pressure of the sub tank 2 is maintained at a constant negative pressure. Thereby, when the inkjet head 3 is arrange | positioned above the subtank 2, it can prevent that an ink leaks from the nozzle of the inkjet 3 by a water head difference. The amount of ink in the sub tank 2 decreases as ink is ejected from the inkjet head 3. For this reason, it is preferable to keep the internal pressure of the sub tank 2 constant even when ink is consumed by ejection. That is, it is preferable that the internal pressure of the sub tank 2 is always adjusted to a constant negative pressure.

  In addition, when the inkjet head 3 is arrange | positioned below the sub tank 2, it is not necessary to maintain the internal pressure of the sub tank 2 constant in this way.

  Here, in the conventional inkjet apparatus, in order to fill the ink from the main tank to the sub tank, a sensor (for example, a capacitance sensor or a light amount sensor) that detects the remaining amount of ink in the sub tank has a sub tank corresponding to each ink. Every one was installed. For example, when three types of ink are used as in the present embodiment, three pairs of sensors for detecting the ink remaining amount in the sub tank are necessary.

  On the other hand, the greatest feature of the ink jet apparatus 100 of the present embodiment is that the ink ejection operation is controlled by the pair of vacuum pumps 8 and the pressure sensor 9 even when a plurality of inks are used. . That is, even when three types of ink are used as in the present embodiment, the remaining amount of ink in each of the three sub tanks 2A, 2B, and 2C is detected by a set of vacuum pump 8 and pressure sensor 9. It is possible. Furthermore, the application of the ink filling driving force and the detection of the amount of ink filled can also be realized by the set of vacuum pump 8 and pressure sensor 9.

  Hereinafter, ink filling from the main tank 1A to the sub tank 2A will be described. That is, an operation for filling a specified amount of ink (until the amount of ink in the sub tank 2A reaches a specified amount) from the main tank 1A to the sub tank 2A will be described.

In the following description, P represents atmospheric pressure, and P7 ₀ , P7 _A0 , and P7 _A represent relative pressure from atmospheric pressure.

Further, it is assumed that the internal volume (V ₇ ) of the reference pressure chamber 7 and the internal volume (V _6A ) of the pressure chamber 6A when the sub tank 2A is not filled with ink are known. Since nothing exists in the reference pressure chamber 7, the internal volume (V ₇ ) of the reference pressure chamber 7 can be calculated relatively accurately from the design value. On the other hand, a bag-like sub tank 2A is contained in the pressure chamber 6A. For this reason, it is difficult to accurately calculate the internal volume (V _6A ) of the pressure chamber 6A from the design value of the pressure chamber 6A. Therefore, the internal volume (V _6A ) of the pressure chamber 6A is preferably measured from a pressure change in a state where ink is not filled. Thus if by calculating the inner volume of the pressure chamber 6A (V _6A) from the pressure change, including the volume of the pipe 23 which connects the pressure chamber 6A and the reference pressure chamber 7, an internal volume (V _6A) There is an advantage that it can be calculated. The internal volume (V _6A ) need only be calculated once.

Specifically, the internal volume (V _6A ) of the pressure chamber 6A can be calculated as follows. First, the air release valve 12 and the shutoff valve 11A are opened, and the pressures in the pressure chamber 6A in which the sub tank 2A is accommodated and the reference pressure chamber 7 are made equal. At this time, the pressure in the pressure chamber 6A and the reference pressure chamber 7 is atmospheric pressure.

Next, the atmosphere release valve 12 and the shutoff valve 11A are closed. Then, the vacuum pump 8 is driven until the pressure in the reference pressure chamber 7 reaches the set negative pressure (P7 ₀ ). If it is confirmed by the pressure sensor 9 that the pressure in the reference pressure chamber 7 has reached the set pressure (P7 ₀ ), the driving of the vacuum pump 8 is stopped. Thereafter, the shutoff valve 11A is opened, and the pressure value (P7 _A0 ) of the pressure sensor 9 is acquired. At this time, the internal volume (V _6A ) of the pressure chamber 6A when the sub tank 2A is not filled with ink can be calculated by the following equation (1).
V _6A = {(P7 ₀ / P7 _A0 ) -1} * V ₇ (1)
In order to fill the sub tank 2A with ink from the main tank 1A, first, the atmosphere release valve 12 and the shutoff valve 11A are opened. Thereby, the pressures in the pressure chamber 6A and the reference pressure chamber 7 become equal to the atmospheric pressure.

Next, the atmosphere release valve 12 and the shutoff valve 11A are closed. Then, the vacuum pump 8 is driven to set the pressure in the reference pressure chamber 7 to a constant negative pressure (P7 ₀ ). If it is confirmed by the pressure sensor 9 that the inside of the reference pressure chamber 7 has become negative pressure (P7 ₀ ), the vacuum pump 8 is stopped. When the vacuum pump 8 is stopped, the shutoff valve 11A is opened, and the pressure value (P7 _A0 ) of the pressure sensor 9 at that time is acquired. At this time, the internal volume (V _2A ) of the sub tank 2A can be calculated by the following equation (2).
V _2A = (1-P7 ₀ / P7 _A0 ) * V ₇ + V _6A (2)
Here, if the internal volume (V _2A ) of the sub-tank 2A obtained by the above equation (2) is less than the specified amount (V _2MAX ) (V _2A <V _2MAX ), the control unit 10 is controlled from the main tank 1A. It is determined that it is necessary to fill the sub tank 2A with ink. When ink filling is necessary, the filling valve 4A is opened, and ink filling into the sub tank 2A is started. Even after the start of filling, the pressure sensor 9 continues to monitor the pressure (P7 ₀ ) in the reference pressure chamber 7. That is, the calculation of the internal volume (V _2A ) of the sub tank 2A is continued by the equation (2). Then, when the internal volume (V _2A ) of the sub tank 2A reaches the specified value (V _2MAX ) (V _2A = V _2MAX ), the pressure value (P7 _A ) is reached, and the filling valve 4A is closed. Thereby, the ink filling from the main tank 1A to the sub tank 2A is completed. Such calculation processing and control are performed by the control unit 10.

The pressure value (P7 _A ) when V _2A = V _2MAX can be calculated by the following equation (3). In the following formula (3), P is atmospheric pressure.
_{P7 A = (V 7 + V} 6A -V 2A) * (P + P7 A0) / (V 7 + V 6A -V 2MAX) -P ··· (3)
Next, the result of actually performing such ink filling operation will be described. Here, the reference pressure chamber 7 whose internal volume (V ₇ ) calculated from the design value is 120 mL was used. Further, the prescribed amount (V _2MAX ) of the internal volume when the sub tank 2A was filled with ink was set to 15 mL.

In addition, the following operation was performed in advance, and the internal volume (V _6A ) of the pressure chamber 6A in a state where the sub tank 2A was not filled with ink was measured. This operation was performed only once. Specifically, the internal volume (V _6A ) of the pressure chamber 6A was calculated by the following method.

  First, the air release valve 12 and the shutoff valve 11A were opened, and the pressures in the pressure chamber 6A in which the sub tank 2A was accommodated and the reference pressure chamber 7 were made equal. At this time, the pressure in the pressure chamber 6A and the reference pressure chamber 7 is atmospheric pressure.

Next, the atmosphere release valve 12 and the shutoff valve 11A are closed. Then, the vacuum pump 8 was driven until the pressure in the reference pressure chamber 7 became the set negative pressure (P7 ₀ ). Here, the pressure (P7 ₀ ) in the reference pressure chamber 7 was set to −10 kPA. It was confirmed by the pressure sensor 9 that the pressure (P7 ₀ ) in the reference pressure chamber 7 became −10 kPA, and the driving of the vacuum pump 8 was stopped. Thereafter, when the shutoff valve 11A was opened, the pressure value (P7 _A0 ) of the pressure sensor 9 was −4.92 kPA. These results were applied to the above equation (1) to calculate the internal volume (V _2A ) of the sub tank 2A. As a result, the internal volume (V _6A ) of the pressure chamber 6A when the sub tank 2A was not filled with ink was about 123.9 mL. The internal volume (V _6A ) includes the volume of the pipe 23 that connects the pressure chamber 6A and the reference pressure chamber 7.
V _6A = {(P7 ₀ / P7 _A0 ) -1} * V ₇ (1)
= {(− 10 / −4.92) −1} * 120
= About 123.9
Based on this result, first, the current ink remaining amount in the sub tank 2A is detected. That is, first, the air release valve 12 and the shutoff valve 11A were opened, and the pressures in the pressure chamber 6A and the reference pressure chamber 7 were set to atmospheric pressure.

Next, the atmosphere release valve 12 and the shutoff valve 11A are closed. Then, the vacuum pump 8 was driven until the pressure in the reference pressure chamber 7 reached the set pressure (P7 ₀ = −10 kPA). When the pressure (P7 ₀ ) in the reference pressure chamber 7 became −10 kPA, the driving of the vacuum pump 8 was stopped. After that, when the shutoff valve 11A was opened, the pressure value (P7 _A0 ) of the pressure sensor 9 was −5.02 kPA. These results were applied to the above equation ( ₂ ) to calculate the internal volume (V _2A ) of the sub tank 2A. As a result, the internal volume (V _2A ) of the sub tank 2A was about 4.86 mL.
V _2A = (1-P7 ₀ / P7 _A0 ) * V ₇ + V _6A (2)
= {1-(-10 / -5.02)} * 120 + 123.9
= About 4.86
As described above, here, the prescribed amount (V _2MAX ) of the internal volume of the sub tank 2A is set to 15 mL. Therefore, (2) it was calculated by the formula _{(V 2A),} the defined amount of internal volume smaller than _{(V 2MAX) (V 2A <} V 2MAX). Therefore, it is necessary to fill the ink from the main tank 1A to the sub tank 2A. In this case, the filling valve 4A is opened, and ink filling from the main tank 1A to the sub tank 2A is started. Even after the ink filling is started, the pressure sensor 9 continues to monitor the pressure (P7 ₀ ) in the reference pressure chamber 7. That is, the pressure (P7 ₀ ) in the reference pressure chamber 7 is monitored until the internal volume (V _2A ) of the sub-tank 2A becomes the specified amount (V _2MAX ) of the _internal volume.

Here, the pressure value (P7 _A ) when the internal volume (V _2A ) of the sub tank 2A is the specified amount (V _2MAX ) (V _2A = V _2MAX ) can be calculated from the above equation (3). As a result, the pressure value (P7 _A ) was −0.81 kPA. Therefore, after the ink filling is started, the filling valve 4A is controlled to be opened when the pressure (P7 ₀ ) in the reference pressure chamber 7 by the pressure sensor 9 becomes −0.81 kPA (P7 _A ). did.
_{P7 A = (V 7 + V} 6A -V 2A) * (P + P7 A0) / (V 7 + V 6A -V 2MAX) -P
... (3)
= (120 + 123.9-4.86) * (100-5.02) / (120 + 123.9-15) -100
= About -0.81
When the volume of ink filled in the sub tank 2A was measured by such ink filling operation, it was 14.7 mL. Therefore, it was demonstrated that the specified amount of ink (V _2MAX = 15 mL) can be filled.

  If the same operation as the ink filling operation from the main tank 1A to the sub tank 2A is performed for the main tanks 1B and 1C and the sub tanks 2B and 2C, a predetermined amount (approximately 15 mL) is added to each of the sub tanks 2B and 2C. ) Ink.

  In addition, it is preferable to maintain the negative pressure by communicating the pressure chamber 6 and the reference pressure chamber 7 when ejecting ink from the inkjet head 3 after filling the sub tank 2. That is, the supply valve 5 is opened, the atmosphere release valve 12 is closed, and the shutoff valve 6 is opened. Thereby, the pressure chamber 6 and the reference pressure chamber 7 are in a communication state. If the vacuum pump 8 is driven in this state, the pressure chamber 6 and the reference pressure chamber 7 are maintained at a negative pressure. Thereby, the negative pressure holding of the sub tank 2 necessary for the ink ejection operation by the inkjet head 3 can be performed.

  As described above, according to the ink jet apparatus 100 of the present embodiment, the set of vacuum pumps 8 can be used even if the main tanks 1A, 1B, 1C and the sub tanks 2A, 2B, 2C are provided independently of each other. The pressure sensor 9 can detect the remaining amount of ink in the sub tank 2, apply a driving force for filling the sub tank 2 with ink, and fill the sub tank 2 with a specified amount of ink. That is, it is not necessary to provide the vacuum pump 8 and the pressure sensor 9 in each sub tank 2A, 2B, 2C. For this reason, even if the kind of ink to be used increases, it is not necessary to increase the vacuum pump 8 and the pressure sensor 9. Thereby, the apparatus structure of the inkjet apparatus 100 can be simplified. Therefore, it is possible to reduce the size of the inkjet device 100.

  In the ink jet apparatus 100 of the present embodiment, the vacuum pump 8 and the pressure sensor 9 are also used for holding the negative pressure of the sub tank 2 when the ink jet head 3 ejects ink. For this reason, the inkjet apparatus 100 can be further reduced in size.

  In the ink jet apparatus 100 of the present embodiment, the ink inflow speed may be controlled when filling the sub tank 2 with ink as necessary. For example, in the inkjet device 100, it is preferable to accurately define the amount of ink flowing into the sub tank 2 (filling amount). For this reason, it is preferable to detect the inflow amount of ink in real time. However, if the flow rate of the ink is too high, the accuracy of detecting the amount of inflow of ink decreases. On the other hand, if the ink flow rate is too slow, the processing time until the ink filling operation is completed becomes long. Here, if the pressure difference is constant, the flow rate becomes slower as the viscosity of the ink or the resistance to the flow path 21 is larger, and the flow velocity is faster as the viscosity of the ink or the resistance to the flow path 21 is smaller. Therefore, when the ink viscosity is low or the resistance to the flow path 21 is low, if the flow rate of the ink is too high, it is preferable to reduce the pressure difference to suppress the flow rate. On the other hand, when the flow rate is slow, the ink inflow amount can be detected under optimum conditions by operating with a large differential pressure.

  For example, it is assumed that one of the two types of ink is likely to flow twice as much as the other ink (the resistance to the flow path 21 is small or the viscosity is small). In this case, when the inflow operation of the ink that tends to flow is performed, the pressure difference between the main tank 1 (atmospheric pressure) and the sub tank 2 is controlled to be ½ times that in the inflow operation of the ink that does not flow easily. To do. As a result, the flow speeds of both inks can be made to be conditions that make it easy to control (detect) the amount of inflow. Thus, the inflow speed of ink can be controlled by changing the negative pressure value applied to the pressure chamber 6.

[Embodiment 2]
Next, a waste liquid system that discharges waste liquid (unused ink) of the ink jet apparatus 100 of FIG. 1 to a waste liquid tank will be described. FIG. 2 is a plan view of such a waste liquid system. The waste liquid system of FIG. 2 stores three types of ink discharged from the inkjet apparatus 100 in a waste liquid tank. In this embodiment as well, when distinguishing these three types of ink, A, B, and C are given after each member, and when not distinguishing the ink, A, B, and C are not explained.

  As shown in FIG. 2, the waste liquid system 110 includes waste liquid tanks 32A, 32B, and 32C that are provided independently for each ink. The waste liquid system 110 includes a pair of vacuum pumps 38, a pressure sensor 39, and a control unit 40, and controls the amount of ink discharged to the waste liquid tank 32 by these.

  The waste liquid tanks 32A, 32B, and 32C are connected to the inkjet heads 3A, 3B, and 3C by independent flow paths 31A, 31B, and 31C, respectively. Each flow path 31A, 31B, 31C is provided with waste liquid valves 34A, 34B, 34C. Thus, the ink (waste liquid) can be discharged from the inkjet head 3 to the waste liquid tank 32 by opening and closing the waste liquid valve 34.

  The waste liquid tanks 32A, 32B, and 32C are provided in the pressure chambers 36A, 36B, and 36C independent of each other. That is, the waste liquid tank 32 is sealed in the pressure chamber 36. In FIG. 2, the pressure chambers 36A, 36B, and 36C are arranged adjacent to each other in this order. Further, a reference pressure chamber 37 is provided adjacent to the pressure chamber 36C of the waste liquid tank 32C. Thus, the four pressure chambers (pressure chambers 36A, 36B, 36C and the reference pressure chamber 37) partitioned from each other are arranged side by side.

  In the reference pressure chamber 37, unlike the pressure chamber 36 in which the waste liquid tank 2 is accommodated, nothing is accommodated therein. A vacuum pump 38 and a pressure sensor 39 are connected to the reference pressure chamber 37. The vacuum pump 38 places the reference pressure chamber 37 in a reduced pressure state. The pressure sensor 39 detects the pressure in the reference pressure chamber 37. In the waste liquid system 110, the pressure and volume in each of the waste liquid tanks 36A, 36B, 36C are calculated by the pair of vacuum pumps 38 and the pressure sensor 39.

  Specifically, the reference pressure chamber 37 and the sub tanks 36 </ b> A, 36 </ b> B, 36 </ b> C are connected by a pipe 33. The piping 33 is branched into the pressure chambers 36A, 36B, and 36C, and shut-off valves 35A, 35B, and 35C are formed in the branched piping 33. The reference pressure chamber 37 is provided with an air release valve 42. Thereby, the pressure in each pressure chamber 36A, 36B, 36C is controllable by operating each cutoff valve 35A, 35B, 35C and the air release valve 42. Further, the volume in the waste liquid tank 36 can be calculated from the detection value of the pressure sensor 39.

  In the inkjet device 100, when maintenance of the inkjet head 3 is executed, bubbles, dust, and the like in the inkjet head 3 (in the nozzle) are discharged together with the ink. The discharged ink is stored in the waste liquid tank 32, and the waste liquid tank 32 is periodically replaced. It should be noted that such ink is also discharged when the ink jet head 3 is replaced and when all the ink of the entire apparatus is discharged when the operation of the ink jet apparatus 100 is stopped.

  Here, when the inkjet apparatus 100 uses a plurality of inks, if the inks are similar in composition to each other, or are inks that do not interfere with mixing with each other, the waste liquid flow path system (the flow path 31 and the waste liquid tank 32). , The waste liquid valve 34) is not provided for each ink and can be combined into one. However, recent production processes are becoming more complex and most often use multiple inks that cannot be mixed together. For example, when different types of ink are mixed, ink that solidifies or aggregates or causes a chemical reaction is often used. In such a case, it is necessary to provide a flow path system including the flow path 31 and the waste liquid tank 32 independently.

  However, in the conventional waste liquid system, when the flow path system is provided independently, a sensor (for example, a capacitance sensor or a light amount sensor) for detecting the remaining amount of waste liquid in the waste liquid tank is provided for each ink type (inkjet head). (Each 3 individually). As a result, there arises a problem that the waste liquid system becomes complicated and large.

  On the other hand, the greatest feature of the waste liquid treatment system 110 of this embodiment is that the waste liquid operation of ink is controlled by a pair of vacuum pumps 38 and a pressure sensor 39 even when a plurality of inks are used. is there. That is, as in this embodiment, even when three types of ink are used, the amount of ink stored in each of the three waste liquid tanks 32A, 32B, and 32C (waste liquid) is reduced by one set of vacuum pump 38 and pressure sensor 39. The amount of ink discharged to the tank 32) can be detected. Furthermore, the application of driving force for ink filling and the detection of the amount of ink filled can also be realized by a set of vacuum pump 38 and pressure sensor 39. As described above, in the waste liquid system 110 according to the present embodiment, the remaining capacity of the waste liquid tank 32 is detected and the driving force for discharging the waste liquid is detected by the set of vacuum pump 38 and the pressure sensor 39 with respect to the discharge operation of the three types of ink. And the amount of liquid to be discharged can be regulated.

Hereinafter, an operation of discharging ink from the inkjet head 3A to the sub tank 32A via the flow path 31A will be described. P represents atmospheric pressure, and P37 ₀ , P37 _A0 , and P37 _A represent relative pressure from atmospheric pressure.

Further, it is assumed that the internal volume (V ₃₇ ) of the reference pressure chamber 37 and the internal volume (V _36A ) of the pressure chamber 36A in a state where the waste liquid is not stored in the waste liquid tank 36A are known. Since nothing exists in the reference pressure chamber 37, the internal volume (V ₃₇ ) of the reference pressure chamber 37 can be calculated relatively accurately from the design value. On the other hand, a waste liquid tank 32A is accommodated in the pressure chamber 36A. For this reason, it is difficult to accurately calculate the internal volume (V _36A ) of the pressure chamber 36A from the design value of the pressure chamber 36A. Therefore, the internal volume (V _6A ) of the pressure chamber 36A is preferably measured from the pressure change in a state where the waste liquid tank 36A is not filled with the waste liquid. Thus if by calculating the inner volume of the pressure chamber 36A _{(V 36A)} from the pressure change, including the volume of the pipe 33 for connecting the pressure chamber 36A and the reference pressure chamber 37, the internal volume _{(V 36A)} There is an advantage that it can be calculated. The internal volume (V _36A ) only needs to be calculated once.

Specifically, the internal volume (V _36A ) of the pressure chamber 36A can be calculated as follows. First, the air release valve 42 and the shutoff valve 35A are opened, and the pressures in the pressure chamber 36A in which the waste liquid tank 32A is accommodated and the reference pressure chamber 37 are made equal. At this time, the pressure in the pressure chamber 36A and the reference pressure chamber 37 is atmospheric pressure.

Next, the atmosphere release valve 42 and the shutoff valve 35A are closed. Then, the vacuum pump 38 is driven until the pressure in the reference pressure chamber 37 reaches the set negative pressure (P37 ₀ ). If it is confirmed by the pressure sensor 39 that the pressure in the reference pressure chamber 37 has reached the set pressure (P37 ₀ ), the driving of the vacuum pump 38 is stopped. Thereafter, the shutoff valve 35A is opened, and the pressure value (P37 _A0 ) of the pressure sensor 39 is acquired. At this time, the internal volume (V _36A ) of the pressure chamber 36A when the waste liquid tank 32A is not filled with ink can be calculated by the following equation (4).
V _36A = {(P37 ₀ / P37 _A0 ) -1} * V ₃₇ (4)
In order to discharge the waste liquid from the flow path 31A to the waste liquid tank 32A, first, the air release valve 42 and the shutoff valve 35A are opened. Thereby, the pressures in the pressure chamber 36A and the reference pressure chamber 37 become equal to the atmospheric pressure.

Next, the atmosphere release valve 42 and the shutoff valve 35A are closed. Then, the vacuum pump 38 is driven to set the pressure in the reference pressure chamber 37 to a constant negative pressure (P37 ₀ ). If it is confirmed by the pressure sensor 39 that the inside of the reference pressure chamber 37 has become negative pressure (P37 ₀ ), the vacuum pump 38 is stopped. If the vacuum pump 38 is stopped, the shutoff valve 35A is opened, and the pressure value (P37 _A0 ) of the pressure sensor 39 at that time is acquired. At this time, the internal volume (V _32A ) of the waste liquid tank 32A can be calculated by the following equation (5).
V _32A = (1−P37 ₀ / P37 _A0 ) * V ₁₃ + V _36A (5)
Here, if the internal volume (V _32A ) of the waste liquid tank 32A obtained by the above equation (5) is less than the specified amount (V _32MAX ) (V _32A <V _32MAX ), the control unit 40 will control the inkjet head 3A. It is determined that the ink (waste liquid) can be discharged to the waste liquid tank 32A. When ink can be discharged, the filling valve 34A is opened, and ink filling into the waste liquid tank 32A is started. Even after the start of discharge, the pressure sensor 39 continues to monitor the pressure (P37 ₀ ) in the reference pressure chamber 37. That is, the calculation of the internal volume (V _32A ) of the waste liquid tank 32A is continued by the equation (5). Then, when the pressure value (P37 _A ) is reached (V _32A = V _D ) when the specified amount (V _D ) of the waste liquid operation is discharged, the filling valve 34A is closed. Thereby, the discharge of the ink from the inkjet head 3A to the waste liquid tank 32A is completed. Such calculation processing and control are performed by the control unit 40.

Note that the pressure value (P37 _A ) when V _32A = V _D can be calculated by the following equation (6). In the following formula (6), P is atmospheric pressure.
_{P37 A = (V 37 + V} 36A -V 32A) * (P + P37 A0) / (V 37 + V 36A - (V 36A + V D)) - P ··· (6)
Next, the result of actually performing such an ink discharging operation will be described. Here, the reference pressure chamber 37 whose internal volume (V ₃₇ ) calculated from the design value is 200 mL was used. Moreover, the maximum storage amount (specified amount V _32MAX ) of the waste liquid tank was set to 100 mL.

Further, the following operation was performed in advance, and the internal volume (V _32A ) of the pressure chamber 36A in a state where the waste liquid was not stored in the waste liquid tank 32 was measured. This operation was performed only once. Specifically, the internal volume (V _32A ) of the pressure chamber 36A was calculated by the following method.

  First, the air release valve 42 and the shutoff valve 35A were opened, and the pressures in the pressure chamber 36A in which the waste liquid tank 32A was accommodated and the reference pressure chamber 37 were made equal. At this time, the pressure in the pressure chamber 36A and the reference pressure chamber 37 is atmospheric pressure.

Next, the atmosphere release valve 42 and the shutoff valve 35A are closed. Then, the vacuum pump 38 was driven until the pressure in the reference pressure chamber 37 reached the set negative pressure (P37 ₀ ). Here, the pressure (P37 ₀ ) in the reference pressure chamber 37 was set to −20 kPA. It was confirmed by the pressure sensor 39 that the pressure (P37 ₀ ) in the reference pressure chamber 37 became −20 kPA, and the driving of the vacuum pump 38 was stopped. After that, when the shutoff valve 35A was opened, the pressure value (P37 _A0 ) of the pressure sensor 39 showed −9.85 kPA. These results were applied to the above equation (4) to calculate the internal volume (V _32A ) of the waste liquid tank 32A. As a result, the internal volume (V _36A ) of the pressure chamber 36A when the sub tank 2A was not filled with ink was about 206.1 mL. The internal volume (V _36A ) includes the volume of the pipe 33 that connects the pressure chamber 36 A and the reference pressure chamber 37.
V _36A = {(P37 ₀ / P37 _A0 ) -1} * V ₃₇ (4)
= {(− 20 / −9.85) −1} * 200
= About 206.1
Based on this result, first, the amount of waste liquid stored in the current waste liquid tank 32A is detected. That is, first, the air release valve 42 and the shutoff valve 35A were opened, and the pressure in the pressure chamber 36A and the reference pressure chamber 37 was set to atmospheric pressure.

Next, the atmosphere release valve 42 and the shutoff valve 35A are closed. Then, the vacuum pump 38 was driven until the pressure in the reference pressure chamber 37 reached the set pressure (P37 ₀ = −20 kPA). When the pressure (P37 ₀ ) in the reference pressure chamber 37 became −20 kPA, the driving of the vacuum pump 38 was stopped. After that, when the shut-off valve 35A was opened, the pressure value (P37 _A0 ) of the pressure sensor 39 was −10.75 kPA. These results were applied to the above equation (5) to calculate the internal volume (V _32A ) of the waste liquid tank 32A. As a result, the waste liquid storage amount (V _32A ) in the waste liquid tank 32A was about 34.0 mL.
V _32A = (1−P37 ₀ / P37 _A0 ) * V ₁₃ + V _36A (5)
= {1-(− 20 / −10.75)} * 200 + 206.1
= About 34.0
As described above, the maximum storage amount (V _32MAX ) of the waste liquid tank is set to 100 mL. Thus, (5) an inner volume determined by the formula _{(V 32A),} the maximum storage amount is smaller than _{(V 32MAX) (V 32A <} V 32MAX). For this reason, a waste liquid operation from the inkjet head 3A to the waste liquid tank 32A is possible. In this case, the waste liquid valve 34A is opened, and the discharge of the waste liquid tank 32A from the inkjet head 3A is started. Even after the ink discharge is started, the pressure sensor 39 continues to monitor the pressure (P37 ₀ ) in the reference pressure chamber 37.

Here, the specified amount (V _D ) for one waste liquid operation is set to 5.0 mL. Therefore, when the specified amount (V _D ) is discharged to the waste liquid tank 32A, the waste liquid operation is terminated. The pressure (P37 ₀ ) in the reference pressure chamber 37 when ink is discharged by the specified amount (V _D ) can be calculated from the above equation (6). As a result, the pressure value (P37 _A ) was −9.53 kPA.
_{P37 A = (V 37 + V} 36A -V 32A) * (P + P37 A0) / (V 37 + V 36A - (V 32A + V D)) - P ··· (6)
= (200 + 206.1-34) * (100-10.75) / (200 + 206.1- (34 + 5))-100
= About -9.53
With such an ink waste liquid operation, the volume of the ink discharged to the waste liquid tank 32A by one waste liquid operation was measured and found to be about 5 mL. Therefore, it was proved that the specified amount (V _D ) of ink discharged in a single waste liquid operation can be discharged.

When the internal volume (V _32A ) of the waste liquid tank 32A reaches the specified amount (V _32MAX ) of the waste liquid tank by monitoring the pressure (P37 ₀ ) in the reference pressure chamber 37, the waste liquid tank 32A is replaced. . The pressure value (P37 _B ) when V _32A = V _32MAX can be calculated by the following equation (7). In the following formula (7), P is atmospheric pressure. As a result, the pressure value (P37 _B ) was −8.49 kPA. Accordingly, if the pressure (P37 ₀ ) in the reference pressure chamber 37 indicates around −8.49 kPA, the waste liquid tank 32A may be replaced.
_{P37 B = (V 37 + V} 36A -V 32A) * (P + P37 A0) / (V 37 + V 36A -V 32MAX) -P ··· (7)
= (200 + 206.1-34) * (100-10.75) / (200 + 206.1-100) -100
= About -8.49
If the same operation as that for discharging ink (waste liquid) from the ink jet head 3A to the waste liquid tank 32A is performed for the ink jet heads 3B and 3C, a specified amount (approximately 5 mL) is applied to each of the waste liquid tanks 32B and 32C. Ink can be discharged.

  As described above, according to the waste liquid system 110 of the present embodiment, even if the waste liquid tanks 32A, 32B, and 32C are provided independently of each other, the waste liquid tank 32 is provided by the set of vacuum pumps 38 and the pressure sensor 39. It is possible to detect the remaining volume of the inside, to apply a driving force for waste liquid operation, and to discharge a specified amount of ink. That is, it is not necessary to provide the vacuum pump 38 and the pressure sensor 39 in each waste liquid tank 32A, 32B, 32C. For this reason, even if the kind of ink to be used increases, it is not necessary to increase the vacuum pump 38 and the pressure sensor 39. Thereby, the apparatus configuration of the waste liquid system 110 can be simplified. Accordingly, it is possible to reduce the size of the waste liquid system 110 and to reduce the size of the inkjet device 100.

  Note that the vacuum pump 38 and the pressure sensor 39 in the waste liquid system 110 may be combined with the vacuum pump 8 and the pressure sensor 9 in the ink jet apparatus 100 of FIG. 1. Thereby, the inkjet apparatus 100 can be further reduced in size.

  In the first embodiment, as described for controlling the ink inflow speed, even in the waste liquid system 110, when the ink discharge speed needs to be controlled, the reference pressure chamber 37 (substantially For this purpose, the negative pressure applied to the pressure chamber 36) may be changed.

  The present invention can also be expressed as follows.

  [1] Container for filling ink (main tank 1, sub tank 2, waste liquid tank 32), first pressure chamber (pressure chambers 3, 36) for maintaining the pressure of the ink container, and flow for allowing liquid to flow into the container A passage (flow passages 21, 31), an opening / closing valve for the passage, a second pressure chamber for pressure adjustment (reference pressure chambers 7, 37), and a pump for adjusting the pressure in the second pressure chamber (pump 8, 38) a pressure sensor (pressure sensors 9 and 39) for detecting the pressure in the second pressure chamber, a mechanism including a valve capable of shutting off the first pressure chamber and the second pressure chamber, and a pressure chamber air release valve; A step of releasing the air to the atmosphere, a step of shutting off the first pressure chamber and adjusting the pressure of the second pressure chamber to a certain negative pressure, and then communicating the pressure chambers to determine the remaining volume of the ink container from the amount of change in the negative pressure; If the remaining volume is equal to or greater than the threshold value, the valve of the flow path is opened to start ink inflow Inkjet apparatus using an extent, the ink inlet mechanism in which the internal pressure second constantly monitors the pressure chamber internal pressure and a step of completing the inlet to close the flow path valve reaches a predetermined value which varies with the ink inlet.

  If such a liquid inflow mechanism is used, the calculation of the remaining volume of the container before inflow and whether or not inflow is possible by simple components such as a pressure adjustment pump and pressure sensor, on-off valves for various flow paths, and a remaining volume calculation system. Operations such as discrimination, inflow operation, constant monitoring of the inflow amount, and regulation of the inflow amount are possible, and an ink inflow mechanism of a small, lightweight and low-cost ink jet apparatus can be realized.

  [2] Container for filling ink (main tank 1, sub tank 2, waste liquid tank 32), first pressure chamber (pressure chambers 3, 36) for maintaining the pressure of the ink container, and flow for allowing liquid to flow into the container A passage (flow passages 21, 31), an opening / closing valve for the passage, a second pressure chamber for pressure adjustment (reference pressure chambers 7, 37), and a pump for adjusting the pressure in the second pressure chamber (pump 8, 38, a pressure sensor for detecting pressure (pressure sensors 9 and 39), a mechanism comprising a valve capable of shutting off the first pressure chamber and the second pressure chamber, and a pressure chamber air release valve; And a step of shutting off the first pressure chamber and adjusting the pressure of the second pressure chamber 2 to a certain negative pressure, communicating both pressure chambers to determine the remaining volume of the ink container from the amount of change in the negative pressure, and sufficient for inflow of ink Adjusting the internal pressure of the first pressure chamber and the second pressure chamber to a correct pressure value; If the remaining volume is greater than or equal to the threshold value, the flow path valve is opened to start ink inflow, and the second pressure chamber pressure that changes with the ink inflow is constantly monitored. When the internal pressure reaches a certain value, the flow path valve is An ink jet apparatus using an ink inflow mechanism comprising a step of closing and finishing the inflow.

  According to this configuration, by adjusting the negative pressure of the pressure chamber, which is the driving force for liquid inflow before liquid inflow, it is possible to adjust the speed of inflow, liquid materials having different viscosities, A wide variety of ink jet apparatuses can be supported.

  [3] An ink jet apparatus using the ink inflow mechanism according to [1] or [2] as a waste liquid operation mechanism for a waste liquid container.

  As described above, when the liquid inflow mechanism of the present invention is used for the waste liquid mechanism of the inkjet apparatus, the waste liquid having a simple configuration having the function of detecting the amount of waste liquid in the waste liquid tank and the function of flowing the waste liquid into the waste liquid tank by a specified amount. The mechanism can be realized.

  [4] An ink jet apparatus using the ink inflow mechanism according to [1] or [2] as an ink filling operation mechanism from a main tank to a sub tank.

  As described above, when the liquid inflow mechanism of the present invention is used for the filling mechanism of the liquid material from the main tank to the sub tank of the ink jet apparatus, the calculation of the consumption amount of the liquid material consumed from the sub tank and the filling function of the liquid material to the sub tank are performed. It is possible to realize a liquid material filling mechanism with a simple configuration including:

  [5] In the ink jet device according to [4], when the ink is not filled from the main tank to the sub tank, the negative pressure in the sub tank can be maintained using the first pressure chamber, the second pressure chamber, the pump, and the pressure sensor. An ink jet apparatus characterized by being performed.

  Thus, by using the pump, pressure sensor, and pressure chamber of the present invention together with the subtank negative pressure holding mechanism of the ink jet device, the subtank negative pressure holding and the consumption amount of the liquid material consumed from the subtank are simplified. It is possible to realize a liquid material supply system having a simple configuration that includes the above calculation and the function of filling the sub tank with the liquid material.

  [6] The ink jet apparatus according to [4] or [5], wherein the filling operation from the main tank to the sub tank of two or more different inks is performed by a single pump and a pressure sensor. Inkjet device.

  Further, if the ink jet apparatus has a plurality of ink jet heads and discharges a plurality of types of liquid materials, even if the ink types increase, a set of pumps and pressure sensors can be used to calculate the consumption of all the liquid materials. The sub tank can be filled with the liquid material and the sub tank can be maintained at a negative pressure, and the size and complexity of the ink jet apparatus can be reduced.

  [7] The ink jet apparatus according to [3], wherein the waste liquid operation of two or more different inks to independent waste liquid tanks is performed by a single pump and a pressure sensor.

  Thus, even if the present invention is used in a waste liquid system of an inkjet apparatus that uses a plurality of liquid materials that cannot be mixed with each other, a plurality of waste liquid flow paths and waste liquid tanks can be used even if the system is independent. A waste liquid system can be constructed by a pump and a pressure sensor.

  Further, the ink jet device of the present invention calculates the remaining volume of the container when the liquid material flows into the container and determines whether or not the inflow can be performed, and starts the inflow when the remaining volume is equal to or greater than a certain value. It can be said that the invention relates to an inflow mechanism for a liquid material, including a method of ending the inflow when the inflow amount reaches a constant value while constantly monitoring the inflow amount.

  According to the present invention, an ink jet apparatus having a simple configuration can be realized by using the liquid inflow mechanism for filling a liquid material from a main tank to a sub tank of the ink jet apparatus or a waste liquid operating mechanism for the waste liquid tank. That is, the ratio of the volume of the second pressure chamber and the volume of the first pressure chamber, which is a reference, is obtained from the pressure change, and the remaining volume of the ink container in the first pressure chamber is calculated. If the remaining volume exceeds a certain value, the inflow is started, the inflow amount is monitored by the pressure change, and the inflow is stopped when it reaches a specified amount. The inflow speed can also be controlled by the initial negative pressure value.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  According to the present invention, in an ink jet apparatus, it is possible to define a liquid material filling operation and a waste liquid operation, a filling amount and a waste liquid amount with a simple configuration. Further, the production process by the ink jet apparatus becomes complicated, and the increase in size and complexity of the apparatus when the types of liquid materials used are increased can be reduced.

It is a top view which shows the principal part structure of the inkjet apparatus of Embodiment 1 of this invention. It is a top view which shows the principal part structure of the inkjet apparatus of Embodiment 2 of this invention.

Explanation of symbols

1, 1A, 1B, 1C Main tank 2, 2A, 2B, 2C Sub tank 3, 3A, 3B, 3C Inkjet head 4, 4A, 4B, 4C Filling valve 5, 5A, 5B, 5C Supply valve 6, 6A, 6B, 6C Pressure chamber 7 Standard pressure chamber 8 Vacuum pump (pump)
9 Pressure sensor 10 Control unit 11, 11A, 11B, 11C Shut-off valve (shut-off unit)
12 Atmospheric release valve (opening part)
32, 32A, 32B, 32C Waste liquid tank 34, 34A, 34B, 34C Waste liquid valve 35, 35A, 35B, 35C Shut-off valve (waste liquid shut-off section)
36, 36A, 36B, 36C Pressure chamber (waste liquid pressure chamber)
37 Reference pressure chamber (waste liquid reference pressure chamber)
38 Vacuum pump (waste liquid pump)
39 Pressure sensor (Waste liquid pressure sensor)
40 Control unit (waste liquid control unit)
42 Air release valve (Waste liquid release part)
100 Inkjet device 110 Waste liquid system

Claims (9)

An inkjet apparatus that discharges a plurality of types of liquid materials,
A main tank and a sub tank provided independently for each liquid material;
An ink jet head for supplying the liquid material of the sub tank filled from the main tank and discharging the supplied liquid material;
A pressure chamber for sealing each sub tank and applying pressure to the sub tank;
A reference pressure chamber that is communicated with each pressure chamber and in which the internal pressure varies;
A pump for adjusting the pressure in the reference pressure chamber;
A pressure sensor for detecting the pressure in the reference pressure chamber;
A shut-off section for switching each pressure chamber and the reference pressure chamber to a communication state or a shut-off state;
A control unit for controlling the driving of the pump and the opening / closing operation of the blocking unit;
The control unit
After the shut-off portion is in the open state, the pressure in each pressure chamber and the pressure in the reference pressure chamber are equalized, then the shut-off portion is in the closed state, and the pressure value of the reference pressure chamber when the reference pressure chamber is held at a negative pressure, From the amount of change from the pressure value of the reference pressure chamber when the blocking portion is opened with the reference pressure chamber held at the negative pressure, the volume in the sub tank is calculated,
An ink jet apparatus that determines whether or not it is necessary to fill a liquid material from a main tank to a sub tank based on the calculated internal volume of the sub tank.   2. The ink jet apparatus according to claim 1, wherein the control unit controls the pressure applied to each sub tank so that the filling speed of each liquid material from the main tank to the sub tank is constant.   The control unit, when not filling the liquid material from the main tank to the sub tank, connects the pressure chamber and the reference pressure chamber, drives the pump, and puts the sub tank in a negative pressure state. The inkjet apparatus according to 1 or 2.   The control unit causes the pressure chamber and the reference pressure chamber to communicate with each other when the ink is ejected from the inkjet head, drives the pump, and sets the sub tank to a negative pressure state. The inkjet device according to any one of the above. An opening for opening the reference pressure chamber and each pressure chamber to the atmosphere;
The control unit keeps the reference pressure chamber at a negative pressure by opening the open portion and the shut-off portion and setting each pressure chamber and the reference pressure chamber to atmospheric pressure and then closing the open portion and the shut-off portion. The volume in the sub-tank is calculated from the amount of change between the pressure value of the reference pressure chamber and the pressure value of the reference pressure chamber when the shut-off portion is opened with the reference pressure chamber held at the above negative pressure. The ink jet apparatus according to claim 1, wherein the ink jet apparatus is an ink jet apparatus.   The inkjet apparatus according to claim 1, further comprising a pair of pumps and a pressure sensor. A plurality of waste liquid tanks for storing liquid materials not discharged from the inkjet head;
Each waste liquid tank is sealed, a waste liquid pressure chamber for applying pressure to the waste liquid tank,
A waste liquid reference pressure chamber that communicates with each waste liquid pressure chamber, and in which the internal pressure fluctuates,
A waste liquid pump for adjusting the pressure in the waste liquid reference pressure chamber;
Waste liquid pressure sensor for detecting the pressure in the waste liquid reference pressure chamber;
A waste liquid blocking section for switching each waste liquid pressure chamber and the waste liquid reference pressure chamber to a communication state or a blocking state;
It has a waste liquid control unit that controls the drive of the waste liquid pump and the opening and closing operation of the waste liquid blocking unit,
The waste liquid control unit
Waste liquid reference pressure when the waste liquid blocking chamber is opened and the pressure of each waste liquid pressure chamber is equalized with the pressure of the waste liquid reference pressure chamber, then the waste liquid blocking section is closed and the waste liquid reference pressure chamber is held at a negative pressure. The volume in the waste liquid tank is calculated from the amount of change between the pressure value in the chamber and the pressure value in the waste liquid reference pressure chamber when the waste liquid blocking section is opened with the waste liquid reference pressure chamber held at the above negative pressure. And
6. The ink jet apparatus according to claim 1, wherein whether or not the liquid material can be discharged from the ink jet head to the waste liquid tank is determined based on the calculated internal volume of the waste liquid tank. A waste liquid opening part that opens the waste liquid reference pressure chamber to the atmosphere is further provided.
The waste liquid control unit opens the waste liquid opening part and the waste liquid blocking part and sets each waste liquid pressure chamber and the waste liquid reference pressure chamber to atmospheric pressure, and then closes the waste liquid opening part and the waste liquid blocking part to close the waste liquid standard. Pressure value of the waste liquid reference pressure chamber when the pressure chamber is held at negative pressure, and pressure value of the waste liquid reference pressure chamber when the waste liquid blocking part is opened with the waste liquid reference pressure chamber held at the above negative pressure 8. The ink jet apparatus according to claim 7, wherein the volume in the waste liquid tank is calculated from the amount of change.   9. The ink jet apparatus according to claim 7, further comprising a pair of waste liquid pump and a waste liquid pressure sensor.

Images