JP6903929B2 - Liquid discharge device - Google Patents

Description

The present invention relates to a technique for ejecting a liquid such as ink.

A valve device (for example, a self-sealing valve) is provided in the liquid flow path communicating with the liquid discharge head. The valve device includes a valve body that opens and closes the flow path in response to a print job from the control device or an operation according to a cleaning command. Deposits due to liquid components may adhere to such a valve body, and the deposits grow as the valve body is repeatedly opened and closed. When the deposit grows and grows, there is a risk that the valve body may be poorly occluded. Therefore, for example, in Patent Document 1, by switching the flow velocity so that the flow velocity of the fluid increases according to the number of times the valve body is opened and closed (the number of times the valve body contacts the valve seat), a problem occurs due to the growth of sediment. Before doing so, the deposits can be removed. Examples of the number of times the valve body is opened and closed include a case where the movement of the valve body is detected by a sensor and directly measured, and a case where the number of times is indirectly estimated from the number of times of printing jobs and cleaning.

Japanese Unexamined Patent Publication No. 2016-168818

However, when the number of times of opening and closing of the valve body is directly measured by the sensor as in Patent Document 1, the number of parts such as the sensor and the electric wiring increases, which may lead to an increase in the size of the valve device. In addition, depending on the usage environment, the transition time from the open state to the closed state of the valve body changes according to changes in the viscosity and temperature of the liquid, so the valve body may open without closing or the valve body may open. It may close early. Therefore, as in Patent Document 1, even if the number of times the valve body is opened and closed is indirectly estimated from the number of times such as printing jobs and cleaning, the estimation accuracy may decrease depending on the usage environment. If the estimation accuracy of the number of times of opening and closing of the valve body is lowered, the timing of removing the deposits may be shifted, and the occurrence of poor blockage of the valve body may not be accurately suppressed. In addition, there is a risk of wasteful consumption of ink and unnecessary replacement of the valve body. In consideration of the above circumstances, an object of the present invention is to accurately suppress the occurrence of defective valve body occlusion.

[Aspect 1]
In order to solve the above problems, the liquid discharge device according to the preferred embodiment (aspect 1) of the present invention is provided in the liquid discharge head for discharging the liquid and the flow path communicating with the liquid discharge head, and discharges the liquid. A valve device including a valve body that opens and closes the flow path according to the operation, and a control device that calculates the number of times the valve body opens and closes based on the non-discharge time during which the liquid is not discharged from the valve device to the flow path. Be prepared. According to the above aspect, since the valve body that opens and closes the flow path according to the liquid discharge operation (printing job, cleaning, etc.) is provided, the valve body opens when the liquid discharge operation is started, and the valve device. Liquid is discharged from the flow path. When the discharge operation is completed, the valve body closes and the liquid is not discharged from the valve device to the flow path. In such a device, the transition time from the open state to the closed state of the valve body changes depending on the usage environment (for example, the viscosity and temperature of the liquid), so that the liquid is not discharged from the valve device to the flow path. Depending on the time, the valve body may open without closing, or the valve body may close early. According to this aspect, since the number of times the valve body is opened and closed is calculated based on the non-discharge time, it is determined whether or not to count the number of times the valve body is opened and closed based on the length of the non-discharge time, and then the determination result is obtained. It can be said that the number of times the valve body is opened and closed is calculated based on. As a result, depending on the usage environment, if there is a high possibility that the valve body will actually open without closing, the number of times the valve body opens and closes will not be counted, and if there is a high possibility that the valve body will close early. It is also possible to count the number of times the valve body is opened and closed. Therefore, in this embodiment, it is possible to improve the estimation accuracy of the number of times the valve body is opened and closed, as compared with the case where the number of times the valve body is opened and closed is indirectly calculated by the number of times such as printing job and cleaning. In this way, by improving the estimation accuracy of the number of times the valve body is opened and closed, it is possible to accurately suppress the occurrence of defective valve body closure.

[Aspect 2]
In a preferred example of aspect 1 (aspect 2), the control device calculates the number of times the valve body is opened and closed based on the viscosity of the liquid or the temperature of the liquid and the non-discharge time. According to the above aspect, since the number of times the valve body is opened and closed is calculated based on the viscosity of the liquid or the temperature of the liquid and the non-discharge time, the accuracy of estimating the number of times the valve body is opened and closed can be improved. Since the transition time from the open state to the closed state of the valve body changes depending on the viscosity of the liquid or the temperature of the liquid, the viscosity of the liquid or the temperature of the liquid depends on the non-discharge time during which the liquid is not discharged from the valve device to the flow path. If, the valve body may open without closing, or the valve body may close early. According to this aspect, it is possible to change the threshold value of the non-discharge time for determining whether or not to count the number of times of opening and closing of the valve body according to, for example, the viscosity of the liquid or the temperature of the liquid. The accuracy of estimating the number of times of opening and closing can be improved.

[Aspect 3]
The liquid discharge device according to a preferred embodiment (aspect 3) of the present invention includes a liquid discharge head that discharges a liquid and a valve device that is provided in a flow path communicating with the liquid discharge head and includes a valve body that opens and closes the flow path. A control device that calculates the number of times the valve body is opened and closed based on the viscosity of the liquid or the temperature of the liquid. According to the above aspect, since the process of calculating the number of times of opening and closing of the valve body is performed based on the viscosity of the liquid or the temperature of the liquid, even if the transition time of the valve body changes depending on the viscosity of the liquid or the temperature of the liquid, it can be calculated. The number of times the valve body is opened and closed can be calculated accordingly. According to this configuration, if the valve body opens without closing due to the viscosity of the liquid or the temperature of the liquid, the number of times the valve body opens and closes is not counted, and if the valve body closes quickly, the valve body does not count. It is possible to count the number of times of opening and closing. Therefore, according to this aspect, the accuracy of estimating the number of times the valve body is opened and closed can be improved.

[Aspect 4]
The liquid discharge device according to a preferred embodiment (aspect 4) of the present invention is provided in a liquid discharge head that discharges a liquid and a flow path that communicates with the liquid discharge head, and opens and closes the flow path according to a liquid discharge operation. A process that prompts the replacement of the valve body and the liquid from the liquid discharge head based on the valve device provided with the valve body, the viscosity of the liquid or the temperature of the liquid, and the non-discharge time during which the liquid is not discharged from the valve device into the flow path. A control device that performs at least one of a process of stopping discharge and a process of cleaning the valve body is provided. According to the above aspect, at least one of the process of urging the replacement of the valve body, the process of stopping the discharge of the liquid from the liquid discharge head, and the process of cleaning the valve body is performed, so that the liquid adheres to the valve body. Poor blockage due to deposits can be avoided or eliminated. Since the viscosity of the liquid or the temperature of the liquid changes depending on the usage environment, the transition time of the valve body changes accordingly, the number of times the valve body opens and closes, and the timing at which deposits adhering to the valve body should be removed also changes. .. In this embodiment, the viscosity of the liquid or the temperature of the liquid is determined by performing a process such as cleaning the valve body based on the viscosity of the liquid or the temperature of the liquid and the non-discharge time during which the liquid is not discharged from the valve device to the flow path. Even if the temperature changes, the timing of performing processing such as cleaning the valve body can be changed accordingly. Therefore, according to this aspect, it is possible to accurately suppress the occurrence of poor occlusion of the valve body.

[Aspect 5]
In any preferred example (aspect 5) of any of aspects 2 to 4, a temperature sensor for detecting the temperature of the liquid is provided, and the control device performs processing according to the detection result by the temperature sensor. According to the above aspect, since the control device performs the above-mentioned processing (processing of calculating the number of times of opening and closing of the valve body, processing of cleaning the valve body, etc.) according to the detection result by the temperature sensor, it depends on the temperature of the liquid. Even if the transition time of the valve body changes, the occurrence of defective valve body occlusion can be accurately suppressed accordingly. In this embodiment, the temperature of the liquid may be measured directly by the temperature sensor, or the temperature of the liquid may be indirectly measured from the ambient temperature measured by the temperature sensor.

[Aspect 6]
In any of the preferred examples (Aspect 6) of Aspects 1 to 5, there are a plurality of types of liquids, and the control device performs processing for each type of liquid. According to the above aspect, since the control device performs the above-mentioned processing (processing for calculating the number of times of opening and closing of the valve body, processing for cleaning the valve body, etc.) for each type of liquid, the valve body is transferred depending on the type of liquid. Even if the deposit amount and the deposit rate of the deposits are different, the timing of performing the above treatment can be changed accordingly. Therefore, according to this aspect, it is possible to accurately suppress the occurrence of poor occlusion of the valve body.

[Aspect 7]
In any of the preferred examples (Aspect 7) of Aspects 1 to 3, the control device does not calculate the number of times the valve body is opened and closed when the liquid is of a specific type. According to the above aspect, since the control device does not calculate the number of times the valve body is opened and closed when the liquid is of a specific type, for example, a liquid (cleaning liquid) that does not contain a component that causes deposits to adhere to the valve body. Etc.), it is possible to prevent the number of times the valve body is opened and closed from being counted. According to such a configuration, it is possible to suppress the excessive calculation of the number of times the valve body is opened and closed, so that the occurrence of defective valve body occlusion can be accurately suppressed.

[Aspect 8]
In a preferred example of aspect 6 or 7 (aspect 8), the control device performs processing according to the elapsed time from the time of production of the liquid. According to the above aspect, the control device performs the above-mentioned processing (processing of calculating the number of times of opening and closing of the valve body, processing of cleaning the valve body, etc.) according to the elapsed time from the time of manufacturing the liquid, and therefore the liquid. Even if the elapsed time from the time of manufacture of the above is longer, the deposits are more likely to adhere, the timing of performing the treatment can be changed accordingly. Therefore, according to this aspect, it is possible to accurately suppress the occurrence of poor occlusion of the valve body.

[Aspect 9]
In any of the preferred examples of Aspects 1 to 3 (Aspect 9), the control device resets the number of times of opening and closing of the valve body by exchanging the valve body or cleaning the valve body, and recalculates. According to the above aspect, the calculation of the number of times of opening and closing of the valve body can be newly started from the replacement of the valve body or the cleaning of the valve body. Therefore, according to this aspect, even if the valve body is replaced or the valve body is cleaned, the subsequent occurrence of defective valve body occlusion can be accurately suppressed.

[Aspect 10]
In any preferred example (aspect 10) of any one of aspects 1 to 3, a storage device for storing the number of times the valve body is opened and closed in association with the valve body is provided. According to the above aspect, even if the valve body is removed, the number of times the valve body is opened and closed can be managed in association with the valve body. Therefore, even if the valve body is temporarily removed and reattached due to maintenance, for example, the number of times of opening and closing can be continuously calculated without being reset. Therefore, since the estimation accuracy of the number of times the valve body is opened and closed can be maintained, the occurrence of defective valve body occlusion can be accurately suppressed even after mounting.

[Aspect 11]
A preferred aspect of the present invention (Aspect 11) is a valve device of a liquid discharge device, which is provided in a flow path communicating with a liquid discharge head for discharging a liquid, and opens and closes the flow path by a contact / detachment operation with respect to a valve seat. It includes a valve body and a storage unit that stores the number of times the valve body is opened and closed in association with the valve device. According to the above aspect, by storing the number of times of opening and closing of the valve body in association with the valve device, it is possible to manage each valve device independently. Therefore, for example, the number of times the valve body is opened and closed not only when it is reattached to the flow path to which the valve device was attached, but also when it is attached to another flow path or to the flow path of another liquid discharge device. Can be calculated continuously without being reset. Therefore, since the estimation accuracy of the number of times of opening and closing of the valve body can be maintained, it is possible to accurately suppress the occurrence of defective valve body closure after the valve device is attached.

[Aspect 12]
In a preferred example of the eleventh aspect (aspect 12), the communication unit is provided to communicate the information on the number of times of opening and closing of the valve body stored in the storage unit with the liquid discharge device by wire or wirelessly. According to the above aspect, since the communication unit that communicates the information on the number of times of opening and closing of the valve body stored in the storage unit with the liquid discharge device by wire or wirelessly is provided, in the liquid discharge device, the communication unit of the valve device is used. Information on the number of times the valve body is opened and closed can be obtained. Therefore, according to this embodiment, it is not necessary to store the information on the number of times the valve body is opened and closed on the liquid discharge device side. Therefore, any liquid discharge device that can communicate with the valve device can be used with the valve device. Even if it is attached, the estimation accuracy of the number of times the valve body is opened and closed can be maintained. As a result, it is possible to accurately suppress the occurrence of defective valve body occlusion after the valve device is attached.

[Aspect 13]
In a preferred example of aspect 12 (aspect 13), an electrode is provided that is exposed to the outside of the liquid discharge device and is connected to a communication unit, and the electrode has a predetermined potential and is connected to a valve body or a valve seat. According to the above aspect, since the electrode is provided so as to be exposed to the outside of the liquid discharge device and connected to the communication unit, the communication unit can communicate with the outside via the electrode. Further, since the electrode of this embodiment has a predetermined potential and is connected to the valve body or the valve seat, the potential of the valve body or the valve seat can be changed by changing the predetermined potential of the electrode. Therefore, it is possible to prevent the liquid component adhering to the valve body or the valve seat from adhering to the valve body or the valve seat due to charging. For example, depending on the zeta potential of the liquid component and the charged state of the valve body or valve seat, the predetermined potential of the electrode is set to an optimum value (for example, -0.5 V) in order to prevent the liquid component from adhering. May be changed to.

[Aspect 14]
In a preferred example of aspect 13 (aspect 14), the predetermined potential of the electrode is the ground potential. According to the above aspect, since the predetermined potential of the electrode is the ground potential, the valve body or the valve seat also becomes the ground potential. Therefore, since the valve body or the valve seat can be prevented from being charged, it is possible to effectively suppress the tendency of the liquid component to adhere to the valve body or the valve seat due to the charging.

[Aspect 15]
In any of the preferred examples of aspects 11 to 14 (aspect 15), the number of times the valve body is opened and closed stored in the storage unit is the viscosity of the liquid, the temperature of the liquid, and the liquid is not discharged from the valve device to the flow path. It is calculated based on at least one of the non-emission time. According to the above aspect, the estimation accuracy of the opening / closing number of the valve body is calculated by calculating the opening / closing number of the valve body based on at least one of the viscosity of the liquid, the temperature of the liquid, and the non-discharge time. Can be improved. Therefore, it is possible to accurately suppress the occurrence of defective valve body occlusion.

[Aspect 16]
A preferred embodiment (aspect 16) of the present invention is a liquid discharge head that discharges a liquid flowing in a flow path communicating with a valve device, and the number of times of opening and closing of a valve body provided in the valve device to open and close the flow path. It is provided with a storage unit for storing the image in association with the valve device, and a nozzle for discharging the liquid supplied from the liquid supply source via the valve device. According to the above aspect, the valve device can be managed on the liquid discharge head side by storing the number of times of opening and closing of the valve body in association with the valve device in the storage unit provided in the liquid discharge head. Therefore, for example, not only when reattaching to the flow path to which the valve device was attached, but also when attaching to another flow path of the liquid discharge head, the number of times of opening and closing of the valve body is not reset and continues. It can be calculated. Therefore, since the estimation accuracy of the number of times of opening and closing of the valve body can be maintained, it is possible to accurately suppress the occurrence of defective valve body closure after the valve device is attached.

[Aspect 17]
In a preferred example of aspect 16 (aspect 17), the number of times the valve body is opened and closed stored in the storage unit is the viscosity of the liquid, the temperature of the liquid, and the non-discharge time during which the liquid is not discharged from the valve device to the flow path. It is calculated based on at least one of. According to the above aspect, the estimation accuracy of the opening / closing number of the valve body is calculated by calculating the opening / closing number of the valve body based on at least one of the viscosity of the liquid, the temperature of the liquid, and the non-discharge time. Can be improved. Therefore, it is possible to accurately suppress the occurrence of defective valve body occlusion.

[Aspect 18]
A preferred aspect of the present invention (aspect 18) is a method for controlling a liquid discharge device, wherein the liquid discharge device is provided in a liquid discharge head for discharging a liquid and a flow path communicating with the liquid discharge head, and is provided with a liquid. A valve device including a valve body that opens and closes the flow path according to a discharge operation, and includes at least one of the viscosity of the liquid, the temperature of the liquid, and the non-discharge time during which the liquid is not discharged from the valve device to the flow path. A first step of determining whether or not to calculate the number of times of opening and closing of the valve body based on the above, and a second step of calculating the number of times of opening and closing of the valve body based on the determination result of the first step are provided. According to the above aspect, in the first step, after determining whether or not to calculate the number of times of opening and closing of the valve body based on the viscosity of the liquid or the like, in the second step, the valve body of the valve body is determined based on the determination result. Since the number of times of opening and closing is calculated, the accuracy of estimating the number of times of opening and closing of the valve body can be improved. Therefore, it is possible to accurately suppress the occurrence of defective valve body occlusion.

[Aspect 19]
A preferred aspect of the present invention (Aspect 19) is a method for controlling a liquid discharge device, wherein the liquid discharge device is provided in a liquid discharge head for discharging a liquid and a flow path communicating with the liquid discharge head, and is provided with a liquid. A valve device comprising a valve body that opens and closes the flow path according to a discharge operation, and the valve body is based on the viscosity of the liquid or the temperature of the liquid and the non-discharge time during which the liquid is not discharged from the valve device into the flow path. At least one of a process of urging the replacement of the liquid, a process of stopping the discharge of the liquid from the liquid discharge head, and a process of cleaning the valve body is performed. According to the above aspect, at least one of the process of urging the replacement of the valve body, the process of stopping the discharge of the liquid from the liquid discharge head, and the process of cleaning the valve body is performed, so that the liquid adheres to the valve body. Poor blockage due to deposits can be avoided or eliminated. Since the viscosity of the liquid or the temperature of the liquid changes depending on the usage environment, the transition time of the valve body changes accordingly, the number of times the valve body opens and closes, and the timing at which deposits adhering to the valve body should be removed also changes. .. In this embodiment, the above treatment is performed based on the viscosity of the liquid or the temperature of the liquid and the non-discharge time during which the liquid is not discharged from the valve device to the flow path, so that even if the viscosity of the liquid or the temperature of the liquid changes. The timing of performing the above processing can be changed accordingly. Therefore, according to this aspect, it is possible to accurately suppress the occurrence of poor occlusion of the valve body.

It is a block diagram of the liquid discharge device which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the structure of a valve device. It is a figure which shows the time change of the flow velocity of the ink discharged from a valve device. It is a figure which shows the relationship between the viscosity of ink and the temperature of ink. It is a figure for demonstrating the relationship between the transition time of a valve body, and the non-discharge time of ink. It is a figure which shows the structure of the data table of the 1st threshold value in 1st Embodiment. It is a flowchart which shows the control of the liquid discharge device performed by the control device. It is a figure which shows the structure of the data table of the 1st threshold value in 2nd Embodiment. It is a figure which shows the structure of the data table of the 2nd threshold value in 3rd Embodiment. It is a figure which shows the modification of the data table of the 2nd threshold value in 3rd Embodiment.

<First Embodiment>
FIG. 1 is a partial configuration diagram of a liquid discharge device 10 according to a first embodiment of the present invention. The liquid ejection device 10 of the present embodiment is an inkjet printing apparatus that ejects ink, which is an example of a liquid, onto a medium 12 such as printing paper. The liquid discharge device 10 shown in FIG. 1 includes a control device 20, a storage device 21, a transfer mechanism 22, a carriage 24, a liquid discharge head 26, and a maintenance unit 30. Although FIG. 1 illustrates a case where one liquid discharge head 26 is mounted on the carriage 24, the present invention is not limited to this, and a plurality of liquid discharge heads 26 may be mounted on the carriage 24. A liquid container (cartridge) 14 for storing ink is attached to the liquid discharge device 10.

The liquid container 14 is an ink tank type cartridge composed of a box-shaped container that can be attached to and detached from the main body of the liquid discharge device 10. The liquid container 14 is not limited to the box-shaped container, and may be an ink pack type cartridge composed of a bag-shaped container. Ink is stored in the liquid container 14. The ink may be black ink or color ink. The ink stored in the liquid container 14 is supplied (pumped) to the liquid discharge head 26 by a pump (not shown). Therefore, the liquid container 14 functions as a liquid supply source for supplying the liquid to the liquid discharge head 26.

The control device 20 includes, for example, a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array). The storage device 21 is composed of a semiconductor memory or the like and is connected to the control device 20. The control device 20 and the storage device 21 are mounted on the control circuit board of the liquid discharge device 10. The control device 20 comprehensively controls each element of the liquid discharge device 10 by executing the program stored in the storage device 21 by the control device 20. Print data representing an image to be formed on the medium 12 is supplied to the control device 20 from an external device (not shown) such as a host computer. The control device 20 controls each element of the liquid discharge device 10 so that the image specified by the print data is formed on the medium 12.

The transport mechanism 22 transports the medium 12 in the Y direction under the control of the control device 20. The liquid ejection head 26 ejects ink from each of the plurality of nozzles N to the medium 12 under the control of the control device 20. A nozzle row is arranged on the liquid discharge head 26. The nozzle array is a set of a plurality of nozzles N arranged linearly along the Y direction. The plurality of nozzles N are formed on the discharge surface 260 of the liquid discharge head 26 facing the medium 12. The number of nozzle rows is not limited to the one shown in the figure. The liquid discharge head 26 includes a plurality of sets (not shown) of pressure chambers and piezoelectric elements corresponding to different nozzles N. By vibrating the piezoelectric element by supplying a drive signal to fluctuate the pressure in the pressure chamber, the ink filled in the pressure chamber is ejected from each nozzle N.

The liquid discharge head 26 is mounted on the carriage 24. The control device 20 reciprocates the carriage 24 in the X direction intersecting the Y direction. A desired image is formed on the surface of the medium 12 by the liquid discharge head 26 ejecting ink to the medium 12 in parallel with the transfer of the medium 12 by the transfer mechanism 22 and the repetitive reciprocation of the carriage 24. For example, it is possible to mount a plurality of liquid ejection heads 26 for ejecting different types of ink on the carriage 24. The direction (vertical direction) perpendicular to the XY plane (plane parallel to the surface of the medium 12) is referred to as the Z direction.

The maintenance unit 30 is arranged in the non-printing area H, which is the home position (standby position) of the carriage 24 in the X direction, for example. The maintenance unit 30 performs maintenance processing on the liquid discharge head 26 when the carriage 24 is in the non-printing area H. The maintenance unit 30 includes a capping mechanism 32 controlled by the control device 20 and a waste liquid tank 34 for accommodating a fluid (cleaning liquid, ink, etc.) discharged from the nozzle N. In the waste liquid tank 34, for example, an absorbent material for holding ink or cleaning liquid is provided.

The capping mechanism 32 is used when capping the discharge surface 260 of the liquid discharge head 26. The capping mechanism 32 includes a cap 322 that seals the nozzle N of the discharge surface 260. The cap 322 is formed in a box shape with the negative side in the Z direction open. When the opening edge of the cap 322 comes into contact with the discharge surface 260, the nozzle N of the discharge surface 260 is sealed. The cap 322 can be moved by a motor (not shown) to the negative side in the Z direction in contact with the discharge surface 260 or to the positive side in the Z direction away from the discharge surface 260. The control device 20 contacts the discharge surface 260 with the cap 322 and seals the nozzle N. At this time, by sucking the thickening ink and air bubbles from the nozzle N with a pump (not shown) communicating with the cap 322, these can be discharged to the cap 322. The ink discharged to the cap 322 is discarded in the waste liquid tank 34 via the flow path (waste liquid flow path) communicating with the cap 322.

Examples of the maintenance process of the liquid discharge head 26 include a cleaning process and a flushing process of the liquid discharge head 26. The cleaning process is a maintenance process in which ink is forcibly discharged from the nozzle N by a pump (not shown) communicating with the cap 322. The flushing process is a maintenance process in which ink is ejected from the nozzle N by applying an ejection waveform to the piezoelectric element. By performing maintenance processing such as cleaning treatment and flushing treatment to discharge thickening ink and air bubbles from nozzle N, clogging of nozzle N and ejection failure can be suppressed.

A valve device 70 is provided in the flow path communicating with the liquid discharge head 26. The valve device 70 of the present embodiment is arranged in the middle of the flow path communicating the liquid container 14 and the liquid discharge head 26. Although the valve device 70 of the present embodiment is configured as a component different from the liquid discharge head 26, the present invention is not limited to this, and the carriage together with the liquid discharge head 26 is not limited to this. It may be mounted on 24. The valve device 70 is a structure in which a flow path for supplying the ink supplied from the liquid container 14 to the liquid discharge head 26 is formed inside. The valve device 70 adjusts the ink pressure by opening / closing (opening / closing) the flow path by the valve body (switching member) 82 described later.

FIG. 2 is a cross-sectional view showing the configuration of the valve device 70 according to the present embodiment. The valve device 70 includes a valve body 82, a valve seat 84, a spring S1, and a spring S2. Roughly speaking, the first flow path R1 opens and closes when the valve body 82 moves to the positive side and the negative side in the W direction with respect to the valve seat 84 and moves in contact with and separate from each other. Specifically, when the valve body 82 moves to the positive side in the W direction and comes into contact with the valve seat 84, the first flow path R1 and the second flow path R2 are blocked, and the first flow path R1 becomes It becomes a closed state. On the other hand, when the valve body 82 moves to the negative side in the W direction and separates from the valve seat 84, the first flow path R1 and the second flow path R2 are communicated with each other, and the first flow path R1 becomes It becomes an open state.

The valve seat 84 is a portion of the support 72 located between the first flow path R1 and the second flow path R2 (the bottom of the recess 722 or the recess 724), and is spaced from the movable portion 762 of the sealing body 76. Open and face each other. A through hole K penetrating the support 72 is formed at substantially the center of the valve seat 84. The through hole K is a foramen rotundum whose inner peripheral surface is parallel to the W direction. The first flow path R1 located on the upstream side of the valve seat 84 and the second flow path R2 located on the downstream side of the valve seat 84 communicate with each other through the through hole K of the valve seat 84.

The valve body 82 is installed in the first flow path R1. The valve body 82 includes a base portion 822, a sealing portion 824, and a valve shaft 826. The base portion 822 is a flat plate-shaped portion formed into a circular shape having an outer diameter larger than the inner diameter of the through hole K. A valve shaft 826 projects coaxially and vertically from the surface of the base portion 822, and an annular sealing portion 824 surrounding the valve shaft 826 in a plan view is installed on the surface of the base portion 822. The valve body 82 is installed so that the base portion 822 and the sealing portion 824 are located in the first flow path R1 in a state where the valve shaft 826 with the axis G directed in the W direction is inserted into the through hole K of the valve seat 84. Will be done. A gap is formed between the inner peripheral surface of the through hole K of the valve seat 84 and the outer peripheral surface of the valve shaft 826. The spring S1 is installed between the sealing body 74 and the base portion 822 of the valve body 82 to urge the valve body 82 toward the valve seat 84 side. On the other hand, the spring S2 is installed between the valve seat 84 and the pressure receiving plate 78 (movable portion 762).

The sealing portion 824 of the valve body 82 is located between the base portion 822 and the valve seat 84, and functions as a seal that closes the through hole K by coming into contact with the valve seat 84. Specifically, the sealing portion 824 comes into contact with the surface (hereinafter referred to as “sealing surface”) S on the first flow path R1 side of the valve seat 84.

According to the valve device 70 having such a configuration, when the pressure in the second flow path R2 is maintained within a predetermined range, the valve body 82 is urged by the spring S1 to urge the peripheral edge of the sealing portion 824. Since the portion comes into contact with the sealing surface S of the valve seat 84, the through hole K of the valve seat 84 is maintained in a state in which the valve body 82 is closed (hereinafter referred to as “closed state”) as shown by the alternate long and short dash line in FIG. To. That is, the first flow path R1 and the second flow path R2 are blocked. On the other hand, when the pressure in the second flow path R2 decreases due to, for example, ink ejection or suction from the outside, the movable portion 762 of the sealing body 76 becomes a valve seat, as shown by the solid line in FIG. The pressure receiving plate 78, which is displaced to the 84 side and is installed in the movable portion 762, presses the valve shaft 826 of the valve body 82 against the urging by the spring S2. That is, the movable portion 762 functions as a diaphragm that is displaced according to the pressure (negative pressure) in the second flow path R2. When the pressure in the second flow path R2 further decreases, the valve shaft 826 is pressed by the movable portion 762 (pressure receiving plate 78), and the valve body 82 opposes the urging of the spring S1 and is on the negative side (sealing) in the W direction. By moving to the body 74 side), as shown by the solid line in FIG. 2, the sealing portion 824 shifts to a state separated from the valve seat 84 (hereinafter referred to as “open state”). In the open state, the through hole K of the valve seat 84 is opened, and the first flow path R1 and the second flow path R2 communicate with each other through the through hole K.

According to such a valve device 70, in a non-printing state, that is, in a state where ink is not consumed, even if ink is pumped from the flow path on the liquid container 14 side upstream of the valve device 70, the valve device 70 Is closed. As a result, the ink from the flow path on the liquid container 14 side is not supplied to the liquid discharge head 26 located on the downstream side of the valve device 70.

On the other hand, when ink is ejected from the nozzle N and the ink is consumed in the printing state, the pressure decreases as the ink in the second flow path R2 decreases, and the second flow path R2 has a negative pressure. become. As a result, the movable portion 762 is displaced to the negative side in the W direction that pushes down the valve body 82, so that the valve body 82 is opened and ink is supplied from the first flow path R1 to the second flow path R2. In this way, the ink from the flow path on the liquid container 14 side is supplied to the liquid discharge head 26. Then, when the negative pressure of the second flow path R2 is eliminated by the inflow of ink into the second flow path R2 of the valve device 70, the movable portion 762 is on the positive side in the W direction as shown by the alternate long and short dash line in FIG. The valve body 82 returns to its original position, the valve body 82 is closed again, and the supply of ink to the liquid discharge head 26 is stopped.

By the way, in the valve device 70 having such a configuration, ink is formed in a minute space formed when the valve body 82 and the valve seat 84 come into contact with each other due to repeated contact of the valve body 82 with the valve seat 84. The components contained in the ink are accumulated and aggregated by compression dehydration. The agglomerated ink has a problem that deposits are generated by adhering to and depositing on the valve body 82 and the valve seat 84. Further, when the SP value (compatibility parameter) of the deposit composed of the ink component is close to the SP value of the valve seat constituent material and the compatibility with the valve seat constituent material is high, the deposit is peeled off from the valve seat 84. Since it is difficult, it sticks to the valve seat 84 as it is and enters the growth process. When the deposit grows and the amount of deposit increases, a gap is formed in the contact surface between the valve body 82 and the valve seat 84, and there is a possibility that the valve body 82 may be poorly closed. In particular, when the valve body 82 is poorly closed in the liquid discharge device 10, ink leaks from the valve body 82, which may cause ink dripping from the nozzle N.

The amount of sediment growth due to the ink components has a strong positive correlation with the number of times the valve body 82 is brought into contact with the valve seat 84, which is the opportunity for solids to aggregate and precipitate due to compression dehydration, that is, the number of times the valve body 82 is opened and closed. .. Therefore, by measuring the number of times the valve body 82 is opened and closed, if the valve body 82 is cleaned and the deposits are removed before the valve body 82 reaches the amount of growth of the leaking deposits, the valve can be valved. It is possible to suppress the occurrence of poor occlusion of the body 82.

However, depending on the measurement accuracy of the number of times the valve body 82 is opened and closed, the timing of the cleaning process of the valve body 82 may be deviated, and the valve body 82 may be poorly closed. On the other hand, for example, if the number of times the valve body 82 is opened and closed is directly measured by detecting the movement of the valve body 82 with a sensor, the measurement accuracy of the number of times the valve body 82 is opened and closed can be improved. However, when the number of times of opening and closing of the valve body 82 is directly measured by the sensor, the number of parts such as the sensor and the electric wiring increases, which may lead to an increase in the size of the valve device 70, which is not preferable.

It is also conceivable to indirectly estimate the number of times the valve body 82 is opened and closed from the number of times such as printing jobs and cleaning. The print job here is, for example, a series of printing commands for continuous printing of a plurality of sheets of medium 12. For example, when a 10-sheet document is printed at one time, the number of prints on the medium 12 is 10, but the number of print jobs is one.

However, depending on the usage environment, the viscosity and temperature of the ink change, and the movement of the valve body 82 also changes accordingly. Therefore, the valve body 82 may open without closing or the valve body 82 may close quickly. .. Therefore, depending on the usage environment, even if the number of times of opening and closing of the valve body 82 is indirectly estimated from the number of times of printing jobs, the actual number of times of opening and closing of the valve body 82 does not match the number of times of printing jobs, etc., and the estimation accuracy Will decrease.

Hereinafter, the factors that reduce the estimation accuracy of the number of times the valve body 82 is opened and closed will be described in more detail. FIG. 3 is a diagram showing a time change of the flow velocity of the ink when the valve body 82 transitions from the open state to the closed state. FIG. 4 is a diagram showing the relationship between the viscosity of the ink and the temperature of the ink. When the ink discharge operation from the valve body 70 is stopped, the valve body 82 is closed through the ink filling operation from the first flow path R1 to the second flow path R2. FIG. 3 shows the state at this time, the horizontal axis is the elapsed time [sec] since the ink discharge operation from the valve device 70 is stopped, and the vertical axis is the first flow path R1 to the second flow path. The ink flow velocity flowing through R2 is [cm ³ / sec].

As shown in FIG. 3, the flow velocity of the ink draws a curve that gradually attenuates with the elapsed time. That is, even if the ink discharge operation from the valve device 70 is stopped, the valve body 82 does not close promptly. Such a transient phenomenon can be interpreted as occurring for the following reasons. When the valve body 82 transitions from the open state to the closed state after the ink discharge operation from the valve device 70 is stopped, the compliance (corresponding to the acoustic capacity) of the movable portion 762 that changes the volume of the second flow path R2. ) C is filled with ink via the flow path resistance R from the first flow path R1 to the second flow path R2.

This means that the change in ink flow velocity with respect to the elapsed time can be treated as a change in current value using the RC series electric circuit as an equivalent circuit, and has a time constant determined by the product of R and C described above. Therefore, FIG. 3 is a graph obtained by calculating the change in ink flow velocity with respect to the elapsed time as a change in current value using an RC series electric circuit as an equivalent circuit. In this case, compliance C hardly changes depending on the environment, but since the flow path resistance R largely depends on the viscosity of the ink, the RC time constant changes according to the viscosity of the ink. That is, the time for the valve body 82 to transition from the open state to the closed state changes depending on the viscosity of the ink.

FIG. 3 shows three graphs y1, y2, and y3 having different ink viscosities. Based on the viscosity of the ink in graph y1, the viscosity of the ink in graph y2 is 0.5 times smaller than that in graph y1, and the viscosity of the ink in graph y3 is 1.5 times larger than that in graph y1. The time constant determined by the product of compliance and flow path resistance is 5.4 sec in graph y1, while it is 2.7 sec, which is smaller than graph y1 in graph y2, and larger than graph y1 in graph y3. It is 1 sec. Therefore, the transition time of the valve body 82 from the open state to the closed state is 27.0 sec in the graph y1, whereas it is 13.5 sec shorter than the graph y1 in the graph y2, and the graph y1 in the graph y3. It will be 40.5 sec, which is longer than that. That is, according to FIG. 3, it can be seen that the transition time for the valve body 82 to transition from the open state to the closed state becomes shorter as the viscosity of the ink decreases, and becomes longer as the viscosity of the ink increases.

FIG. 4 shows three graphs yA, yB, and yC with different ink types. yA is a graph of ink A, yB is a graph of ink B, and yC is a graph of ink C. According to the graphs yA, yB, and yC of FIG. 4, it can be seen that the lower the temperature of the ink, the higher the viscosity of the ink, and the higher the temperature of the ink, the lower the viscosity of the ink. Further, the viscosity of the ink A is lower than the viscosity of the ink B, and the viscosity of the ink C is higher than the viscosity of the ink B. As described above, the viscosity of the ink differs depending on the type of ink (for example, the color of the ink).

According to FIGS. 3 and 4, it can be seen that the viscosity of the ink changes depending on the temperature of the ink, and the transition time for the valve body 82 to transition from the open state to the closed state also changes accordingly. That is, the lower the temperature of the ink, the higher the viscosity of the ink, and the higher the viscosity of the ink, the higher the flow path resistance. Therefore, the valve body 82 also becomes difficult to move and the transition time of the valve body 82 becomes long. On the other hand, the higher the temperature of the ink, the lower the viscosity of the ink, and the lower the viscosity of the ink, the lower the flow path resistance. Therefore, the valve body 82 also becomes easier to move and the transition time of the valve body 82 becomes shorter. When the discharge of ink from the valve device 70 is started and the valve body 82 transitions from the closed state to the open state, the pressure receiving plate 78 (moving portion 762) forcibly pushes the valve shaft 826 of the valve body 82. Since the valve body 82 starts to open, the transition is instantaneous.

As described above, in the valve device 70 shown in FIG. 2, when the valve body 82 transitions from the open state to the closed state, the transition time differs depending on the viscosity of the ink and the temperature of the ink. Therefore, for example, depending on the relationship between the time from the end of the print job to the start of the next print job, that is, the non-discharge time during which ink is not discharged from the valve device 70 to the flow path and the transition time of the valve body 82. , The valve body 82 may open without closing, or the valve body 82 may close early.

FIG. 5 is a diagram for explaining the relationship between the transition time of the valve body 82 and the non-discharge time of the ink. In FIG. 5, the ink non-discharge time V is the ink discharge time from the valve device 70, for example, the time from the end of the print job to the start of the next print job. The transition times T and T'of the valve body 82 are transition times (open state → closed state) in which the valve body 82 transitions from the closed state to the open state.

As shown in FIG. 5, when the print job is completed, the valve body 82 starts to close, becomes a closed state with the lapse of the transition time, and when the next print job is started, the valve body 82 starts to open. For example, assuming that the transition time of the valve body 82 is T, when the transition time T is shorter than the non-discharge time V of the ink, the next print job is started after the valve body 82 is closed. .. In this case, since the valve body 82 is opened and closed, the number of printing jobs matches the number of times the valve body 82 is opened and closed.

However, in an environment where the ink temperature is lower than that in the case of the transition time T of the valve body 82, the transition time transition time of the valve body 82 is T', which is longer than T. When the transition time T'is longer than the non-discharge time V of the ink, the next print job is started before the valve body 82 is closed. In this case, since the valve body 82 is opened without closing, the valve body 82 is not actually opened and closed and remains in the open state. In such a case, the number of times the valve body 82 is opened and closed does not match the number of print jobs, and the accuracy of estimating the number of times the valve body 82 is opened and closed is lowered. If the estimation accuracy of the number of times of opening and closing of the valve body 82 is lowered, the timing of removing the deposits may be shifted, and the occurrence of poor occlusion of the valve body 82 may not be accurately suppressed. Further, if the number of times of opening and closing is counted excessively, there is a possibility that wasteful ink consumption may be caused or the valve body 82 may be unnecessarily replaced.

Therefore, in order to accurately suppress the occurrence of poor blockage of the valve body 82, the control device 20 of the present embodiment opens and closes the valve body 82 based on the non-discharge time V in which ink is not discharged from the valve device 70 to the flow path. Performs the process of calculating the number of times. Specifically, when the control device 20 shown in FIG. 1 executes a predetermined program, the control device 20 functions as the determination unit 202 and the processing unit 204. The determination unit 202 determines whether or not to count the number of times the valve body 82 is opened and closed depending on whether or not the non-discharge time V exceeds the first threshold value P. The processing unit 204 performs a process of calculating the number of times of opening and closing of the valve body 82 based on the determination result by the determination unit 202. Further, the determination unit 202 determines whether or not the integrated value of the number of times of opening and closing of the valve body 82 exceeds the second threshold value Q. The processing unit 204 executes a predetermined process such as cleaning the valve body 82 based on the determination result by the determination unit 202.

As shown in FIG. 5, for example, if the transition time T of the valve body 82 is set to the first threshold value P, when the non-discharge time V exceeds the first threshold value P, the valve is valved before the next print job is started. Since there is a high possibility that the body 82 will close, the determination unit 202 determines that the number of times the valve body 82 is opened and closed is counted. On the other hand, if the non-emission time V does not exceed the first threshold value P, there is a high possibility that the valve body 82 will open without closing before the next print job is started. Therefore, the determination unit 202 Determines that the number of times the valve body 82 is opened and closed is not counted. Therefore, since the non-discharge time V in FIG. 5 does not exceed the first threshold value P, the number of times the valve body 82 is opened and closed is not counted.

As described above, in the present embodiment, after the determination unit 202 determines whether or not the number of times of opening and closing of the valve body 82 is counted depending on whether or not the non-discharge time V exceeds the first threshold value P, the processing unit 204 Counts the number of times the valve body 82 is opened and closed based on the determination result of the determination unit 202. According to this configuration, the accuracy of estimating the number of times the valve body 82 is opened and closed can be improved. Moreover, since the transition time T of the valve body 82 changes depending on the usage environment such as the ink temperature and the ink viscosity, the usage environment changes by changing the first threshold P also according to the ink temperature and the ink viscosity. It is also possible to improve the estimation accuracy of the number of times the valve body 82 is opened and closed.

Specifically, the data table 212 in which the ink temperature D and the first threshold value P as shown in FIG. 6 are associated with each other is stored in the storage device 21. The ink temperature D is associated so that the first thresholds P1, P2, ... Pn correspond to each predetermined temperature range (D1 <D≤D2, D2 <D≤D3, ... Dn <D≤Dn + 1). There is. Further, a temperature sensor 15 for detecting the temperature of the ink is provided in the flow path on the upstream side of the valve device 70. However, the arrangement position of the temperature sensor 15 is not limited to the example. For example, the temperature sensor 15 may be arranged in the flow path on the downstream side of the valve device 70, or the temperature sensor 15 may be arranged in the valve device 70. In the present embodiment, the case where the temperature of the ink is directly measured by the temperature sensor 15 has been illustrated, but the present invention is not limited to this. For example, the temperature of the ink may be indirectly measured from the atmospheric temperature measured by the temperature sensor 15.

The determination unit 202 acquires the first threshold value P corresponding to the temperature range in which the temperature of the ink detected by the temperature sensor 15 enters from the data table 212. The determination unit 202 determines whether or not to count the number of times the valve body 82 is opened and closed depending on whether or not the non-discharge time V exceeds the first threshold value P acquired from the data table 212.

For example, in FIG. 5, when the ink temperature changes and the transition time of the valve body 82 changes to T', the determination unit 202 sets the temperature range in which the changed ink temperature enters in the data table 212 shown in FIG. The first threshold value P corresponding to is acquired. For example, if the first threshold value P acquired by the determination unit 202 is P2, it is determined whether or not to count the number of times the valve body 82 is opened and closed based on the P2. Since the non-discharge time V in FIG. 5 exceeds the first threshold value P2, the determination unit 202 determines that the number of times the valve body 82 is opened and closed is counted. The processing unit 204 counts the number of times the valve body 82 is opened and closed based on the determination result of the determination unit 202. Since the transition time T of the valve body 82 also changes depending on the viscosity of the ink, the first threshold value P may also be changed according to the viscosity of the ink.

The viscosity of the ink may also change depending on the elapsed time t from the time of manufacturing the ink. For example, as the elapsed time t becomes longer, the ink may become thicker, which may cause the transition time T to fluctuate. Therefore, a margin based on the fluctuation of the transition time T as described above may be added as a correction value to the first threshold value P acquired from the data table 212. Further, in the first embodiment, the case where the data table 212 is used to acquire the first threshold value P is illustrated, but instead of using the data table 212, the ink temperature, the ink viscosity, the ink type, and the like will be described later. A function or the like indicating the relationship between any of the elapsed times from the time of manufacture of the ink to be used and the first threshold value P may be used.

As described above, according to the present embodiment, even if the viscosity of the ink and the temperature of the ink differ depending on the usage environment, the number of times the valve body 82 is opened and closed can be calculated accordingly. Therefore, the accuracy of estimating the number of times the valve body 82 is opened and closed can be significantly improved as compared with the case where the number of times the valve body 82 is opened and closed is indirectly calculated based on the number of times such as printing jobs and cleaning. Further, by improving the estimation accuracy of the number of times of opening and closing of the valve body 82, it is possible to perform processing such as removing the deposits adhering to the valve body 82 at an appropriate timing, so that the valve body 82 may be poorly blocked. It can be suppressed accurately. It is possible to suppress wasteful consumption of ink and unnecessary force to replace the valve body 82.

The non-discharge time V in which the ink is not discharged from the valve device 70 to the flow path is the time from when the ink is not discharged from the valve device 70 to the flow path until the ink is discharged from the valve device 70 to the flow path again. Is. Therefore, the non-discharge time V of such ink may be acquired as the time from the end of the print job to the start of the print job, and the time during which the ink is not discharged from the valve device 70 to the flow path is directly measured and acquired. You may. Further, the time during which the ink is discharged from the valve device 70 to the flow path may be measured, and the non-discharge time V of the ink may be obtained from the measurement result.

In addition, the ink is discharged from the valve device 70 not only when the print job is performed, but also when the print stop in the print job shifts to the print restart, and when the flushing process and the cleaning process described above are performed. Therefore, the non-emission time V of the present embodiment includes not only the time from the end of the print job to the start of the next print job, but also the time from the print stop in the print job to the restart of printing, and the end of the cleaning process. It also includes the time from to the start of the flushing process. Further, the non-emission time V of the present embodiment also includes a time from the stop of the cleaning process to the restart of the cleaning process and a time from the stop of printing to the start of the flushing process. Further, during the non-discharge time V of the present embodiment, not only the process of ejecting ink from the liquid ejection head 26, but also the liquid ejection head without ejecting ink from the liquid ejection head 26 even when the ink is ejected from the valve device 70. A process of circulating ink in the flow path in 26 is also included.

Hereinafter, the control method of the liquid discharge device 10 according to the present embodiment will be described. FIG. 7 is a flowchart showing the control of the liquid discharge device 10 performed by the control device 20. As shown in FIG. 7, in step S101, the determination unit 202 of the control device 20 acquires the ink non-emission period V. Specifically, if the process of ejecting ink from the valve device 70, such as a print job, is the ink ejection operation, the determination unit 202 starts the ink ejection operation immediately before the ink ejection operation. The time from the end of the process to the start of the current ink ejection operation is acquired as the ink non-ejection period V. For example, when the print job is started, the determination unit 202 acquires the time from the end of the print job immediately before that to the start of the current print job as the ink non-discharge period V.

Subsequently, in step S102 (first step), the determination unit 202 determines whether or not the non-emission period V exceeds the first threshold value P. In this way, the determination unit 202 determines whether or not to count the number of times the valve body 82 is opened and closed by determining whether or not the non-discharge period V exceeds the first threshold value P. Specifically, first, the determination unit 202 acquires the first threshold value P based on the data table 212. The determination unit 202 acquires the first threshold value corresponding to the temperature of the ink detected by the temperature sensor 15 from the first threshold values P1, P2, ... Pn stored in the data table 212. At this time, if the determination unit 202 has acquired the first threshold value P2, the determination unit 202 determines whether or not the non-emission period V exceeds the first threshold value P2. Then, when the determination unit 202 determines that the non-discharge period V exceeds the first threshold value P2, the processing unit 204 performs a process of counting the number of times the valve body 82 is opened and closed in step S103 (second step). .. On the other hand, when the determination unit 202 determines that the non-emission period V does not exceed the first threshold value P2, the process returns to the process of step S101. Therefore, in this case, the number of times the valve body 82 is opened and closed is not counted.

According to steps S101 and S102, the number of times the valve body 82 is opened and closed is calculated based on the temperature of the ink and the non-discharge time V, so that the accuracy of estimating the number of times the valve body 82 is opened and closed can be improved. .. Moreover, since the first threshold value P of the non-emission time V for determining whether or not to count the number of times the valve body 82 is opened and closed is changed according to the ink temperature, the valve body is used even in an environment where the ink temperature is different. The estimation accuracy of the number of times of opening and closing of 82 can be improved. In steps S101 and S102, the number of times the valve body 82 is opened and closed may be calculated based on the viscosity of the ink and the non-emission time V. The viscosity of the ink in this case may be detected by a sensor or may be specified based on the type of ink.

Next, in step S104, the determination unit 202 determines whether or not the integrated value of the number of times of opening and closing of the valve body 82 exceeds the second threshold value Q. The second threshold value Q is stored in the storage device 21. The determination unit 202 acquires the second threshold value Q from the storage device 21 and compares it with the integrated value of the number of times the valve body 82 is opened and closed. When the determination unit 202 determines that the integrated value of the number of times the valve body 82 is opened and closed does not exceed the second threshold value Q, the determination unit 202 returns to the process of step S101. On the other hand, when the determination unit 202 determines that the integrated value of the number of times the valve body 82 is opened and closed exceeds the second threshold value Q, the processing unit 204 executes a predetermined process in step S105.

The processing unit 204 executes at least one of a process of urging the replacement of the valve body 82, a process of stopping the ejection of ink from the liquid ejection head 26, and a process of cleaning the valve body 82 as predetermined processes. To do. Examples of the process for prompting the replacement of the valve body 82 include an error display displayed on a display unit (not shown) included in the liquid discharge device 10 and notification of an error by sound or voice. Examples of the process of stopping the ejection of ink from the liquid ejection head 26 include pausing the print job, pausing the cleaning process, and pausing the flushing process. Examples of the process of cleaning the valve body 82 include a process of increasing the flow velocity of the ink flowing in the valve device 70. In addition, in the process of cleaning the valve body 82, the portion where the valve body 82 contacts the valve seat 84 is composed of an elastic member, and the valve body 82 is pressed against the valve seat 84 so that the elastic members intersect in the W direction. It may be a process of rubbing against the valve seat 84. The process of cleaning the valve body 82 may be a cleaning performed while the valve body 82 is attached to the liquid discharge device 10, or may be a cleaning performed while the valve body 82 is removed from the liquid discharge device 10. Before the process of cleaning the valve body 82, a process of prompting the replacement of the valve body 82 may be performed.

In this way, the valve is valved by executing at least one of a process of prompting the replacement of the valve body 82, a process of stopping the ejection of ink from the liquid ejection head 26, and a process of cleaning the valve body 82. It is possible to avoid or eliminate the occurrence of poor obstruction due to deposits adhering to the body. Further, according to the present embodiment, the estimation accuracy of the number of times of opening and closing of the valve body 82 is improved by performing a process such as cleaning of the valve body 82 based on the viscosity of the ink or the temperature of the ink and the non-discharge time V. Therefore, even if the deposits adhering to the valve body 82 grow, it is possible to carry out a process such as cleaning of the valve body 82 at an appropriate timing before the defective closure of the valve body 82 occurs. As a result, it is possible to accurately suppress the occurrence of poor blockage of the valve body 82 due to deposits. Further, by changing the second threshold value Q according to the viscosity of the liquid or the temperature of the liquid, it is possible to change the timing of performing processing such as cleaning of the valve body 82.

When the valve body 82 is replaced or the valve body 82 is cleaned, the control device 20 resets the number of times the valve body 82 is opened and closed and recalculates the calculation. According to this, the calculation of the number of times of opening and closing of the valve body 82 can be newly started from the replacement of the valve body 82 or the cleaning of the valve body 82. Therefore, even if the valve body 82 is replaced or the valve body 82 is cleaned, the subsequent occurrence of poor occlusion of the valve body 82 can be accurately suppressed.

Further, the control device 20 may perform processing such as cleaning of the valve body 82 described above for each type of ink. Even if the amount of deposits deposited on the valve body 82 and the deposition rate differ depending on the type of ink, the timing of performing processing such as cleaning of the valve body 82 can be changed accordingly. Therefore, it is possible to accurately suppress the occurrence of poor blockage of the valve body 82 depending on the type of ink. Further, the control device 20 may not calculate the number of times the valve body 82 is opened and closed when the liquid is of a specific type. Specific types of liquids include, for example, cleaning liquids, pretreatment liquids, posttreatment liquids, dye inks and the like. Since the cleaning liquid and the like do not contain components that are deposited as solids on the valve body 82, the deposits do not adhere even if the valve body 82 and the valve seat 84 come into contact with each other. For example, the control device 20 specifies the type of liquid according to the type of the liquid container 14, and when the liquid is a specific type, the control device 20 does not count the number of times the valve body 82 is opened and closed. According to this, in a specific type of liquid that does not contain a component that causes deposits to adhere to the valve body 82, the number of times the valve body 82 is opened and closed is not counted, so that the determination unit 202 and the processing unit 204 are not counted. Load can be reduced.

Further, the storage device 21 may store the number of times of opening and closing of the valve body 82 in association with the valve body 82. According to this configuration, even if the valve body 82 is removed, the number of times the valve body 82 is opened and closed can be managed in association with the valve body 82. Therefore, even if the valve body 82 is temporarily removed and reattached due to maintenance, for example, the number of times of opening and closing can be continuously calculated without being reset. Therefore, even after the valve body 82 is attached, the estimation accuracy of the number of times the valve body 82 is opened and closed can be maintained, so that the occurrence of poor occlusion of the valve body 82 can be accurately suppressed.

The number of times the valve body 82 is opened and closed associated with the valve body 82 may be held by the valve device 70. Specifically, as shown in FIG. 1, the valve device 70 may include a storage unit 702 that stores the number of times the valve body 82 is opened and closed. According to this, the number of times of opening and closing of the valve body 82 associated with the valve body 82 can be stored in the storage unit 702 of the valve device 70. In this way, by storing the number of times the valve body 82 is opened and closed in association with the valve device 70, it is possible to manage each valve device 70 independently. Therefore, for example, the valve body 82 is not only reattached to the flow path to which the valve device 70 is attached, but also when it is attached to another flow path or to the flow path of another liquid discharge device 10. The number of times of opening and closing of is not reset and can be continuously calculated. Therefore, since the estimation accuracy of the number of times of opening and closing of the valve body 82 can be maintained, it is possible to accurately suppress the occurrence of defective closing of the valve body 82 after the valve device 70 is attached.

The number of times of opening and closing of the valve body 82 associated with the valve body 82 may be stored in a storage unit (not shown) included in the liquid discharge head 26. The valve device 70 can be managed on the liquid discharge head 26 side by storing the number of times the valve body 82 is opened and closed in association with the valve device in the storage unit included in the liquid discharge head 26. Therefore, for example, not only when the valve device 70 is reattached to the flow path to which the valve device 70 is attached, but also when it is attached to another flow path of the liquid discharge head 26, the number of times the valve body 82 is opened and closed is not reset. It can be calculated continuously. Therefore, since the estimation accuracy of the number of times of opening and closing of the valve body 82 can be maintained, it is possible to accurately suppress the occurrence of defective closing of the valve body 82 after the valve device 70 is attached. The number of times the valve body 82 stored in the storage unit 702 of the valve device 70 or the storage unit of the liquid discharge head 26 is opened / closed is based on at least one of the viscosity of the ink, the temperature of the ink, and the non-discharge time V. It is calculated by.

Further, the valve device 70 of the present embodiment includes a communication unit 704 that communicates information on the number of times of opening and closing of the valve body 82 stored in the storage unit 702 with the control device 20 of the liquid discharge device 10 by wire or wirelessly. As a result, in the liquid discharge device 10, information on the number of times of opening and closing of the valve body 82 can be acquired from the communication unit 704 of the valve device 70. According to this configuration, it is not necessary to store information on the number of times the valve body 82 is opened and closed on the liquid discharge device 10 side. Therefore, no matter what liquid discharge device 10 is attached to the liquid discharge device 10 as long as the liquid discharge device 10 can communicate with the valve device 70, the estimation accuracy of the number of times of opening and closing of the valve body 82 can be maintained. It is possible to accurately suppress the occurrence of poor occlusion of the valve body 82 after mounting.

The valve device 70 may be provided with an electrode (not shown) that is exposed to the outside of the liquid discharge device 10 and is connected to the communication unit 704. According to this configuration, the communication unit 704 can communicate with the outside via the electrodes. The electrode has a predetermined potential and is connected to the valve body 82 or the valve seat 84. According to this configuration, the potential of the valve body 82 or the valve seat 84 can be changed by changing the predetermined potential of the electrode. Therefore, it is possible to prevent the ink component adhering to the valve body 82 or the valve seat 84 from being easily adhered to the valve body 82 or the valve seat 84 due to charging. For example, the predetermined potential of the electrode may be the ground potential (ground). According to this, the valve body 82 or the valve seat 84 also becomes the ground potential. Therefore, since the valve body 82 or the valve seat 84 can be prevented from being charged, it is possible to effectively suppress that the ink component is likely to adhere to the valve body 82 or the valve seat 84 due to the charging. Further, depending on the zeta potential of the ink component and the charged state of the valve body 82 or the valve seat 84, in order to prevent the ink component from adhering, a predetermined potential of the electrode is set to an optimum value (for example, −0.5 V). Etc.).

<Second Embodiment>
A second embodiment of the present invention will be described. For the elements whose actions and functions are the same as those of the first embodiment in each of the embodiments exemplified below, the reference numerals used in the description of the first embodiment will be diverted and detailed description of each will be omitted as appropriate. FIG. 8 is a diagram showing the configuration of the data table 212 of the first threshold value P in the second embodiment. The data table 212 of FIG. 8 illustrates a case where the first threshold value P is stored for each type of ink.

In the data table 212, the ink temperature D and the first threshold value P are associated with each ink type (yA ink A, yB ink B, yC ink C shown in FIG. 4). According to FIG. 4, the viscosity of the ink changes for each type of ink, and for each type of ink, the higher the temperature of the ink, the lower the viscosity, and the lower the temperature of the ink, the higher the viscosity. Therefore, since the transition time for the valve body 82 to transition from the open state to the closed state also changes depending on the type of ink, the relationship with the non-discharge time V in which the ink is not discharged from the valve device 70 depends on the type of ink and its temperature. Therefore, there may be a case where the valve body 82 is opened without closing or a case where the valve body 82 is closed early.

In the second embodiment, the first threshold value P in which the ink temperature and the first threshold value P are associated with each other is stored in the data table 212 for each type of ink. As a result, in step S104 of FIG. 7, the determination unit 202 can determine whether or not to count the number of times the valve body 82 is opened and closed for each type of ink. According to the second embodiment, the accuracy of estimating the number of times of opening and closing of the valve body 82 can be improved even when the amount of deposits deposited on the valve body 82 and the deposition rate differ depending on the type of ink. In addition, since the timing of performing processing such as cleaning of the valve body 82 can be changed depending on the type of ink, the occurrence of poor blockage of the valve body 82 due to the deposits adhering to the valve body 82 can be accurately generated for each type of ink. Can be suppressed.

<Third Embodiment>
A third embodiment of the present invention will be described. In the third embodiment, a case where the control device 20 performs a process of calculating the number of times of opening and closing of the valve body 82 and a process of cleaning the valve body 82 according to the elapsed time from the time of manufacturing the ink is illustrated. FIG. 9 is a diagram showing a data table 212'of the second threshold value Q in the third embodiment. The data table 212'in FIG. 9 associates the elapsed time t from the time of manufacturing the ink (manufacturing date, etc.) with the second threshold value Q, and is stored in the storage device 21. The elapsed time t from the time of manufacturing the ink is such that the second threshold values Q1, Q2, ... Qn correspond to each predetermined range (t1 <t≤t2, t2 <t≤t3, ... tn <t≤tn + 1). Is associated with. The longer the elapsed time from the time of ink production, the more the ink components aggregate and the more easily deposits adhere. Therefore, in the data table 212', the longer the elapsed time t from the time of ink production, the second threshold Q. Make it smaller.

In the third embodiment, in step S104 of FIG. 7, the determination unit 202 specifies, for example, the manufacturing time stored in the electronic tag of the liquid container 14 as the manufacturing time of the ink, and starts from the manufacturing time of the ink. The elapsed time t is calculated. The determination unit 202 acquires the second threshold value Q corresponding to the calculated elapsed time t from the time of manufacture of the ink from the data table 212'of FIG. Then, the determination unit 202 determines whether or not the integrated value of the number of times of opening and closing of the valve body 82 exceeds the second threshold value Q acquired from the data table 212'of FIG. When the integrated value of the number of times of opening and closing of the valve body 82 exceeds the second threshold value Q, the processing unit 204 performs a predetermined process such as cleaning of the valve body 82 in step S105.

According to such a configuration, even if the elapsed time from the time of manufacturing the ink is longer, the deposits are more likely to adhere, by acquiring the second threshold value Q corresponding to the elapsed time, the above-mentioned cleaning of the valve body 82 and the like can be performed. It can be changed so that the timing of performing the processing of is shortened. Therefore, it is possible to accurately suppress the occurrence of poor clogging of the valve body 82 according to the elapsed time from the time of manufacturing the ink. The determination unit 202 specifies the time of manufacture of the ink based on the information input by the user from the operation unit (not shown) of the liquid discharge device 10 (for example, the information at the time of manufacture described on the package of the liquid container 14). Then, the elapsed time t from the time of manufacture of the specified ink may be calculated.

Further, the data table 212'of the second threshold value Q is not limited to that illustrated in FIG. For example, as in the data table 212'shown in FIG. 10, the elapsed time t from the time of manufacturing the ink and the second threshold value Q may be associated with each type of ink. According to the data table 212'of FIG. 10, the determination unit 202 can acquire the second threshold value Q according to the elapsed time t from the time of manufacturing the ink for each type of ink. Therefore, the timing of performing processing such as cleaning of the valve body 82 can be changed for each type of ink. According to such a configuration, it is possible to accurately suppress the occurrence of poor blockage of the valve body 82 due to the deposits adhering to the valve body 82 according to the elapsed time t from the time of manufacturing the ink for each type of ink. .. In the third embodiment, the case where the data table 212'of FIG. 9 or 10 is used to acquire the second threshold value Q is illustrated, but instead of using the data table 212', the type of ink and the type of ink are used. A function or the like indicating the relationship between any of the elapsed time from the time of ink production and the first threshold value P may be used.

<Modification example>
The embodiments and embodiments exemplified above can be variously modified. A specific mode of modification is illustrated below. Two or more aspects arbitrarily selected from the following examples and the above aspects can be appropriately merged to the extent that they do not contradict each other.

(1) In the above-described embodiment, the serial head in which the carriage 24 on which the liquid discharge head 26 is mounted is repeatedly reciprocated along the X direction is illustrated, but the line head in which the liquid discharge heads 26 are arranged over the entire width of the medium 12 is illustrated. The present invention can also be applied to the above.

(2) In the above-described embodiment, the piezoelectric liquid discharge head 26 using a piezoelectric element that applies mechanical vibration to the pressure chamber is illustrated, but a heat generating element that generates air bubbles inside the pressure chamber by heating is illustrated. It is also possible to adopt the thermal type liquid discharge head used.

(3) The liquid discharge device 10 illustrated in the above-described embodiment can be adopted in various devices such as a facsimile machine and a copier, in addition to a device dedicated to printing. However, the application of the liquid discharge device 10 of the present invention is not limited to printing. For example, a liquid discharge device that discharges a solution of a coloring material is used as a manufacturing device for forming a color filter of a liquid crystal display device, an organic EL (Electroluminescence) display, an FED (field emission display), or the like. Further, a liquid discharge device that discharges a solution of a conductive material is used as a manufacturing device for forming wiring and electrodes on a wiring board. It is also used as a chip manufacturing device that discharges a solution of a bioorganic substance as a kind of liquid.

10 ... Liquid discharge device, 12 ... Medium, 14 ... Liquid container, 15 ... Temperature sensor, 20 ... Control device, 202 ... Judgment unit, 204 ... Processing unit, 21 ... Storage device, 212 ... Data table, 22 ... Conveyance mechanism, 24 ... Carriage, 26 ... Liquid discharge head, 260 ... Discharge surface, 30 ... Maintenance unit, 32 ... Capping mechanism, 322 ... Cap, 34 ... Waste liquid tank, 70 ... Valve device, 702 ... Storage unit, 704 ... Communication unit, 72 ... Support, 722 ... Recessed, 724 ... Recessed, 74 ... Sealed body, 76 ... Sealed body, 762 ... Movable part, 78 ... Pressure receiving plate, 82 ... Valve body, 822 ... Base, 824 ... Sealed part, 286 ... Valve shaft, 84 ... Valve seat, A, B, C ... Ink, D ... Ink temperature, G ... Axis line, H ... Non-printing area, K ... Through hole, N ... Nozzle, P ... First threshold, Q ... 2nd threshold, R1 ... 1st flow path, R2 ... 2nd flow path, S ... sealing surface, S1 ... spring, S2 ... spring, T, T'... valve body transition time, V ... non-discharge time.

Claims (18)

A liquid discharge head that discharges liquid and
A valve device provided in a flow path communicating with the liquid discharge head and provided with a valve body that opens and closes the flow path according to the liquid discharge operation.
A liquid discharge device including a control device that performs a first process of calculating the number of times of opening and closing of the valve body based on a non-discharge time during which the liquid is not discharged from the valve device to the flow path. The control device assumes that the valve body is closed when the non-discharge time is longer than the first threshold value and the valve body is open when the non-discharge time is shorter than the first threshold value. The liquid discharge device according to claim 1, wherein the liquid discharge device is characterized in that. The liquid discharge device according to claim 2, wherein the control device changes the first threshold value based on the temperature of the liquid. The liquid discharge device according to claim 2 or 3, wherein the control device has a different first threshold value based on the viscosity of the liquid. The liquid discharge device according to any one of claims 2 to 4, wherein the control device has a different first threshold value based on the type of the liquid. The liquid discharge device according to any one of claims 2 to 5, wherein the control device has a different first threshold value based on an elapsed time from the time of manufacture of the liquid. The control device performs a process of urging the replacement of the valve body, a process of stopping the discharge of the liquid from the liquid discharge head, and the valve body based on the integrated value of the number of times of opening and closing calculated by the first process. The liquid discharge device according to any one of claims 1 to 6, wherein at least one of the cleaning processes is performed as a second process. 7. The control device is characterized in that the second process is performed when the integrated value is larger than the second threshold value, and the second process is not performed when the integrated value is smaller than the second threshold value. The liquid discharge device according to. The liquid discharge device according to claim 8 , wherein the control device changes the second threshold value based on the temperature of the liquid. The liquid discharge device according to claim 8 or 9, wherein the control device has a different second threshold value based on the viscosity of the liquid. The liquid discharge device according to any one of claims 8 to 10, wherein the control device has a different second threshold value based on the type of the liquid. The liquid discharge device according to any one of claims 8 to 11, wherein the control device has a different second threshold value based on an elapsed time from the time of manufacture of the liquid. The liquid discharge device according to any one of claims 1 to 12, wherein the control device does not perform the first process when the liquid is of a specific type. Claims 1 to 13 are characterized in that, when the valve body is replaced or the valve body is cleaned, the control device resets the integrated value of the number of times of opening and closing calculated by the first process. The liquid discharge device according to any one of. The liquid discharge device according to any one of claims 1 to 14, wherein the valve device includes a storage device that stores an integrated value of the number of times of opening and closing calculated by the first process. The liquid discharge device according to claim 15, wherein the valve device includes a communication unit that wirelessly communicates with the liquid discharge device. A liquid discharge head that discharges liquid and
A valve device provided in a flow path communicating with the liquid discharge head and provided with a valve body that opens and closes the flow path.
A liquid discharge device including a control device that performs a first process of calculating the number of times of opening and closing of the valve body based on the viscosity of the liquid or the temperature of the liquid. A liquid discharge head that discharges liquid and
A valve device provided in a flow path communicating with the liquid discharge head and provided with a valve body that opens and closes the flow path according to the liquid discharge operation.
A process of urging the replacement of the valve body, a process of stopping the discharge of the liquid from the liquid discharge head, and a process of cleaning the valve body based on the non-discharge time during which the liquid is not discharged from the valve device to the flow path. A liquid discharge device including a control device that performs at least one of the above processes as a second process.

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