LIQUID SUPPLY SYSTEM, CONTROL METHOD, NON-TRANSITORY COMPUTER-READABLE MEDIUM STORING COMPUTER-READABLE INSTRUCTIONS, AND LIQUID SUPPLY DEVICE

A liquid supply system supplies a liquid from a server tank to a printer tank via a tube by a liquid delivery mechanism. A processor of the liquid supply system causes the liquid delivery mechanism to perform a supply and return operations. A first tank is one of the server tank or the printer tank. A second tank is different from the first tank, of the server tank and the printer tank. The processor causes the liquid delivery mechanism to perform a liquid delivery operation before the supply and return operations, when a remaining amount of the liquid in the first tank becomes equal to or greater than a first prescribed remaining amount. The liquid delivery operation is the supply or return operation of delivering the liquid from the first tank to the second tank via the tube.

REFERENCE TO RELATED APPLICATIONS

This application claims priority from Japanese Patent Application No. 2022-191862 filed on Nov. 30, 2022. The entire content of the priority application is incorporated herein by reference.

BACKGROUND ART

A liquid supply system that supplies a liquid to a printer is known. The liquid supply system is provided with a main tank and the printer. Ink is stored in the main tank as one type of the liquid. The printer is provided with a sub tank. The sub tank is connected to the main tank via a main tank tube. The liquid supply system supplies the ink from the main tank to the sub tank via the main tank tube.

DESCRIPTION

In the above-described liquid supply system, in order to cause a state of the ink, such as a temperature distribution, a density distribution and the like, to be uniform, it is conceivable to circulate the ink between the main tank and the sub tank via the main tank tube. In this case, there is a possibility that an amount of the ink in the main tank after the circulation changes from an amount of the ink in the main tank before the circulation, and an amount of the ink in the sub tank after the circulation changes from an amount of the ink in the sub tank before the circulation. Thus, if the amount of ink in the main tank continues to increase as a result of the circulation being repeatedly performed, there is a possibility that ink may overflow from the main tank. If the amount of ink in the sub tank continues to increase as a result of the circulation being repeatedly performed, there is a possibility that the ink may overflow from the sub tank.

Embodiments of the broad principles derived herein provide a liquid supply system, a control method, a non-transitory computer-readable medium storing computer-readable instructions, and a liquid supply device that contribute to suppressing a liquid from overflowing from a tank.

A first aspect of the present disclosure relates to a liquid supply system supplying a liquid to a printer tank. The printer tank is a tank provided in a printer. The liquid supply system includes a tube, a liquid delivery mechanism, a processor, and a memory. The tube connects the printer tank and a server tank configured to store the liquid. The liquid delivery mechanism is provided in the tube, and is configured to perform a supply operation of supplying the liquid from the server tank to the printer tank via the tube, and a return operation of returning the liquid from the printer tank to the server tank via the tube. The memory stores computer-readable instructions that, when executed by the processor, cause the processor to perform processes. The processes include circulation processing of causing the liquid delivery mechanism to perform the supply operation and the return operation, and first liquid delivery processing of, when a remaining amount of the liquid in a first tank becomes equal to or greater than a first prescribed remaining amount, causing the liquid delivery mechanism to perform a liquid delivery operation before the circulation processing. The first tank is one of the server tank or the printer tank. The liquid delivery operation is the supply operation or the return operation of delivering the liquid from the first tank to a second tank via the tube. The second tank is, of the server tank and the printer tank, different from the first tank.

According to the first aspect, when the remaining amount of the liquid in the first tank becomes equal to or greater than the first prescribed remaining amount, before the circulation processing, the liquid is delivered from the first tank to the second tank by the first liquid delivery processing. In this way, the remaining amount of the liquid in the first tank decreases. Thus, even when the circulation processing is subsequently performed, the liquid is suppressed from overflowing from the first tank. As a result, the processor contributes to suppressing the liquid from overflowing from the first tank.

A second aspect of the present disclosure relates to a control method by a liquid supply system supplying a liquid to a printer tank. The printer tank is a tank provided in a printer. The liquid supply system includes a tube and a liquid delivery mechanism. The tube connects the printer tank and a server tank configured to store the liquid. The liquid delivery mechanism is provided in the tube. The liquid delivery mechanism is configured to perform a supply operation of supplying the liquid from the server tank to the printer tank via the tube, and a return operation of returning the liquid from the printer tank to the server tank via the tube. The control method includes circulation processing of causing the liquid delivery mechanism to perform the supply operation and the return operation, and first liquid delivery processing of, when a remaining amount of the liquid in a first tank becomes equal to or greater than a first prescribed remaining amount, causing the liquid delivery mechanism to perform a liquid delivery operation before the circulation processing. The first tank is one of the server tank or the printer tank. The liquid delivery operation is the supply operation or the return operation of delivering the liquid from the first tank to a second tank via the tube. The second tank is, of the server tank and the printer tank, different from the first tank.

The second aspect contributes to the seme advantage as the first aspect.

A third aspect of the present disclosure relates to a non-transitory computer-readable medium storing computer-readable instructions executed by a computer of a liquid supply system supplying a liquid to a printer tank. The printer tank is a tank provided in a printer. The liquid supply system includes a tube and a liquid delivery mechanism. The tube connects the printer tank and a server tank configured to store the liquid. The liquid delivery mechanism is provided in the tube. The liquid delivery mechanism is configured to perform a supply operation of supplying the liquid from the server tank to the printer tank via the tube, and a return operation of returning the liquid from the printer tank to the server tank via the tube. The instructions, when executed by the computer, causes the computer to perform processes. The processes includes circulation processing of causing the liquid delivery mechanism to perform the supply operation and the return operation, and first liquid delivery processing of, when a remaining amount of the liquid in a first tank becomes equal to or greater than a first prescribed remaining amount, causing the liquid delivery mechanism to perform a liquid delivery operation before the circulation processing. The first tank is one of the server tank or the printer tank. The liquid delivery operation is the supply operation or the return operation of delivering the liquid from the first tank to a second tank via the tube. The second tank is, of the server tank and the printer tank, different from the first tank.

The third aspect contributes to the seme advantage as the first aspect.

A fourth aspect of the present disclosure relates to a liquid supply device supplying a liquid to a printer tank. The printer tank is a tank provided in a printer. The liquid supply device includes a tube, a liquid delivery mechanism, a processor, and a memory. The tube connects the printer tank and a server tank configured to store the liquid. The liquid delivery mechanism is provided in the tube, and is configured to perform a supply operation of supplying the liquid from the server tank to the printer tank via the tube, and a return operation of returning the liquid from the printer tank to the server tank via the tube. The memory stores computer-readable instructions that, when executed by the processor, cause the processor to perform processes. The processes include circulation processing of causing the liquid delivery mechanism to perform the supply operation and the return operation, and first liquid delivery processing of, when a remaining amount of the liquid in a first tank becomes equal to or greater than a first prescribed remaining amount, causing the liquid delivery mechanism to perform a liquid delivery operation before the circulation processing. The first tank is one of the server tank or the printer tank. The liquid delivery operation is the supply operation or the return operation of delivering the liquid from the first tank to a second tank via the tube. The second tank is, of the server tank and the printer tank, different from the first tank.

OVERALL CONFIGURATION OF LIQUID SUPPLY SYSTEM100

A liquid supply system100according to an embodiment of the present disclosure will be described with reference to the appended drawings. As shown inFIG.1, the liquid supply system100includes a plurality of printers1, and a liquid supply device2. The liquid supply system100supplies an ink, for example, as a liquid, to each of the plurality of printers1, from the liquid supply device2.

A number of the plurality of printers1is not limited to a particular number, and, for example, four printers1A,1B,1C, and1D are connected to the single liquid supply device2. The printer1is an inkjet printer, for example, and performs printing by ejecting the ink onto a print medium (not shown in the drawings). The print medium is a cloth, paper, or the like, and is a T-shirt, for example.

The ink is, for example, white (W), black (K), yellow (Y), cyan (C), or magenta (M). Hereinafter, of the five colors of the ink, the white color ink will be referred to as “white ink,” and when the four colors of the black, cyan, yellow and magenta inks are collectively referred to, or when one of the inks is not particularly specified, they will be referred to as “color inks.”

The white ink is used in printing as a portion representing white in an image, or as a base for the color inks. The color inks are ejected directly onto the print medium, or onto the base created using the white ink, and are used in printing of a color image.

<Mechanical Configuration of Printer1>

The printer1is provided with a platen15, a carriage13, and a head14shown inFIG.2. The platen15is provided to be moveable in a sub-scanning direction. The print medium is placed on the platen15. The carriage13is provided to be movable in a main scanning direction. The main scanning direction is orthogonal to the sub-scanning direction.

The head14is mounted to the carriage13, and moves together with the carriage13in the main scanning direction. The head14includes nozzles and ejects white ink from the nozzles onto the print medium on the platen15. In addition to the head14, the printer1is provided with a head or a plurality of heads (hereinafter referred to as the “other heads”). In the present embodiment, the other heads are not shown in the drawings, and a description thereof is simplified. The other heads are different from the head14in that the other heads eject the color inks, rather than the white ink, from the nozzles onto the print medium on the platen15.

The printer1is provided with a printer tank17W. The printer tank17W receives the supply of the white ink from the liquid supply device2, and stores the supplied white ink. The printer tank17W is connected to the head14shown inFIG.2, via a tube (not shown in the drawings).

In addition to the printer tank17W, the printer1is provided with a plurality of printer tanks (hereinafter referred to as “other printer tanks”). In the present embodiment, the other printer tanks are not shown in the drawings, and a description thereof is simplified. The other printer tanks differ from the printer tank17W in that the other printer tanks receive the supply of the color inks from the liquid supply device2, in place of the white ink. The other printer tanks are connected to the other heads via tubes (not shown in the drawings).

The white ink is supplied from the printer tank17W to the head14shown inFIG.2via the tube (not shown in the drawings), by the driving of a supply mechanism184shown inFIG.2. Similarly, the color inks are supplied to the other heads from the other printer tanks. The carriage13moves in the main scanning direction as a result of the driving of a main scanning motor181shown inFIG.2. The platen15moves in the sub-scanning direction as the result of the driving of a sub-scanning motor182shown inFIG.2. In this way, the head14moves in the main scanning direction and the sub-scanning direction relative to the print medium on the platen15.

While the head14moves in the main scanning direction and the sub-scanning direction relative to the print medium on the platen15, the head14ejects the white ink from the nozzles onto the print medium on the platen15as a result of the driving of a head driver183shown inFIG.2. Similarly, the other heads eject the color inks from the nozzles onto the print medium on the platen15. As a result of the above, the printer1performs print processing of printing on the print medium.

<Mechanical Configuration of Liquid Supply Device2>

The liquid supply device2is provided with a server tank6W, tubes8, and an agitation mechanism96. The server tank6W is positioned outside the plurality of printers1, and stores the white ink. A capacity of the white ink that can be stored by the server tank6W is greater than a capacity of the white ink that can be stored by the single printer tank17W, and is greater than a total of the capacities of the white ink that can be stored by the printer tanks17W of the printers1A,1B,1C, and1D. The tubes8configure flow paths of the white ink between the server tank6W and the respective printer tanks17W of the plurality of printers1.

The agitation mechanism96is a propeller stirrer, for example, and performs an agitation operation of agitating the white ink inside the server tank6W, as a result of the driving of an agitation motor963shown inFIG.3. In the present embodiment, the white ink includes, as solid components such as pigment particles and the like, components that are more prone to settling than components included in the color inks. The component prone to settling is titanium oxide, for example. The titanium oxide is a type of inorganic pigment having a relatively high specific gravity. Since the white ink includes the component that is relatively prone to settling, the pigment particles and the like in the white ink easily precipitate as the solid components. Hereinafter, the precipitation of the solid components in the white ink will also be referred to as “settling of the white ink.” By performing the agitation operation, the agitation mechanism96suppresses the settling of the white ink inside the server tank6W.

Note that, in addition to the server tank6W, the liquid supply device2is provided with a plurality of server tanks (hereinafter referred to as “other server tanks”) and, in addition to the tubes8, is provided with a plurality of tubes (hereinafter referred to as “other tubes”). In the present embodiment, the other server tanks and the other tubes are not shown in the drawings, and a description thereof is simplified.

The other server tanks differ from the server tank6W in that the other server tanks store the color inks rather than the white ink. The other tubes configure flow paths of the color inks between the other server tanks and respective other printer tanks of the plurality of printers1. The other tubes differ from the tube8in that the other tubes are not provided with tubes84,85, and86to be described later. Note that in the present embodiment, the agitation mechanism96is not provided in the other server tanks.

<Flow Path Configuration of White Ink>

A flow path of the white ink includes a first white flow path W1and a second white flow path W2. Note thatFIG.1shows the first white flow path W1using solid lines and shows the second white flow path W2using dotted lines. The first white flow path W1connects the server tank6W and the respective printer tanks17W of the printers1A and1B to each other. The second white flow path W2connects the server tank6W and the respective printer tanks17W of the printers1C and1D to each other.

The first white flow path W1and the second white flow path W2differ from each other in whether the connection destination from the liquid supply device2is one of the printers1A and1, or the printers1C and1D. Thus, hereinafter, the first white flow path W1will be described and, for the second white flow path W2, the same reference signs will be assigned as for the first white flow path W1and the description thereof will be omitted or simplified.

The first white flow path W1is configured by tubes81, tubes82and83, and tubes84,85, and86as the tubes8. The tube81is connected to the server tank6W. The tube81extends from inside the server tank6W to a point P1. The tube81is connected to the tube82and the tube83at the point P1.

The tube82extends from the point P1toward the printer tank17W of the printer1A via a point P2, and is connected to the printer tank17W of the printer1A. The tube83extends from the point P1toward the printer1B via a point P3, and is connected to the printer tank17W of the printer1B.

The tube84is connected to the tube82at the point P2. The tube84extends from the point P2to a point P4, and is connected to the tube86at the point P4. The tube85is connected to the tube83at the point P3. The tube85extends from the point P3to the point P4, and is connected to the tube86at the point P4. The tube86extends from the point P4toward the server tank6W, and is connected to the server tank6W.

Hereinafter, the flow path from the server tank6W to the printer tank17W of the printer1A via the tube81and the tube82, and the flow path from the server tank6W to the printer tank17W of the printer1B via the tube81and the tube83will be respectively referred to as a “supply flow path.” The side of the server tank6W in the supply flow path will be referred to as “upstream in the supply flow path,” and the side of the printer tank17W of the printer1A or the printer1B will be referred to as “downstream in the supply flow path.” For example, at a halfway point in the supply flow path, the side of the server tank6W is upstream in the supply flow path and the side of the printer tank17W of the printer1A or the printer1B is downstream in the supply flow path.

The flow path from the printer tank17W of the printer1A to the server tank6W via the tube84and the tube86, and the flow path from the printer tank17W of the printer1B to the server tank6W via the tube85and the tube86will be respectively referred to as a “circulation flow path.” The side of the printer tank17W of the printer1A or the printer1B in the circulation flow path will be referred to as “upstream in the circulation flow path,” and the side of the server tank6W will be referred to as “downstream in the circulation flow path.” For example, at a halfway point in the circulation flow path, the side of the printer tank17W of the printer1A or the printer1B is upstream in the circulation flow path and the side of the server tank6W is downstream in the circulation flow path.

A supply pump20, a supply valve22, and a filter24are provided in the tube82. A supply pump21, a supply valve23, and a filter25are provided in the tube83. The supply pump20is positioned further upstream in the supply flow path than the point P2. The supply pump21is positioned further upstream in the supply flow path than the point P3.

As a result of being respectively driven by pump motors201and211shown inFIG.3, the supply pumps20and21suck up the white ink from the server tank6W via the tube81. As a result of being driven by the pump motor201shown inFIG.3, the supply pump20sends the sucked up white ink toward the printer tank17W of the printer1A, via the tube82. As a result of being driven by the pump motor211shown inFIG.3, the supply pump21sends the sucked up white ink toward the printer tank17W of the printer1, via the tube83.

Hereinafter, a state in which a valve is closed will be referred to as a “closed state,” and a state in which valve is open will be referred to as an “open state.” In the closed state, the valve causes the flow path to be in a blocked state. In the open state, the valve causes the flow path to be in a communicated state.

The supply valve22is positioned further upstream in the supply flow path than the supply pump20. The supply valve23is positioned further upstream in the supply flow path than the supply pump21. The supply valves22and23switch between the closed state and the open state as a result of being driven by solenoids221and231shown inFIG.3, respectively. In the closed state, the supply valve22causes the tube82to be in the blocked state, and in the open state, causes the tube82to be in the communicated state. In the closed state, the supply valve23causes the tube83to be in the blocked state, and in the open state, causes the tube83to be in the communicated state.

The filter24is positioned further upstream in the supply flow path than the supply valve22. The filter25is positioned further upstream in the supply flow path than the supply valve23. The filters24and25are respectively configured by a non-woven fabric, a woven fabric, a resin film, or a porous metal piece, for example, and filter the white ink.

A circulation pump26and a circulation valve28are provided in the tube84. A circulation pump27and a circulation valve29are provided in the tube85. As a result of being driven by a pump motor261shown inFIG.3, the circulation pump26sucks up the white ink from the printer tank17W of the printer1A, via a portion of the tube82further downstream in the supply flow path than the point P2. As a result of being driven by a pump motor271shown inFIG.3, the circulation pump27sucks up the white ink from the printer tank17W of the printer1i, via a portion of the tube83further downstream in the supply flow path than the point P3. As a result of being respectively driven by the pump motors261and271shown inFIG.3, the circulation pumps26and27send the sucked up white ink toward server tank6W, via the tube86.

The circulation valve28is positioned further downstream in the supply flow path than the circulation pump26. The circulation valve29is positioned further downstream in the circulation flow path than the circulation pump27. The circulation valves28and29switch between the closed state and the open state as a result of being driven by solenoids281and291shown inFIG.3, respectively. In the closed state, the circulation valve28causes the tube84to be in the blocked state, and in the open state, causes the tube84to be in the communicated state. In the closed state, the circulation valve29causes the tube85to be in the blocked state, and in the open state, causes the tube85to be in the communicated state.

In the above-described configuration, by causing one or both of the supply valves22and23to be in the open state and driving, of the supply pump20and the supply pump21, the supply pump corresponding to the valve[s] in the open state, the liquid supply system100supplies the white ink from the server tank6W to the printer tank17W via the tube8.

Hereinafter, an operation in which the liquid supply system100supplies the liquid from the server tank6W toward the printer tank17W via the tube8will be referred to as a “supply operation.” In the supply operation of the present embodiment, the liquid supply system100can supply the white ink from the server tank6W to each of the plurality of printer tanks17W of the plurality of printers1, via the tube8, in parallel or to one of the plurality of printers1at a time. In other words, in each of the supply flow paths to the plurality of printers1, the server tank6W is positioned further upstream than each of the plurality of printers1.

As an example of a flow of the white ink when the supply operation has been performed, a flow of the white ink from the server tank6W via the tube8toward the printer tanks17W of each of the printers1A and1B in the first white flow path W1will be described. When the white ink is supplied from the server tank6W to the printer tank17W of the printer1A, the white ink flows from the server tank6W toward the printer tank17W of the printer1A via the tube81and the tube82(refer to arrows A1). When the white ink is supplied from the server tank6W to the printer tank17W of the printer1, the white ink flows from the server tank6W toward the printer tank17W of the printer1B via the tube81and the tube83(refer to arrows A2).

In a state in which one or both of the circulation valve28and the circulation valve29are in the open state, of the circulation pump26and the circulation pump27, the liquid supply system100drives the circulation pump corresponding to the valve[s] in the open state, and thus returns the white ink from the printer tank17W toward the server tank6W, via the tube8.

Hereinafter, an operation in which the liquid supply system100returns the white ink from the printer tanks17W toward the server tank6W via the tube8will be referred to as a “return operation.” In the return operation of the present embodiment, the liquid supply system100can return the white ink from the plurality of printer tanks17W of each of the plurality of printers1to the server tank6W, via the tube8, in parallel or from one of the plurality of printers1at a time.

As an example of a flow of the white ink when the return operation has been performed, a flow of the white ink from the printer tank17W of each of the printers1A and1B via the tube8toward the server tank6W in the first white flow path W1will be described. When the white ink is returned to the server tank6W from the printer tank17W of the printer1A, the white ink flows from the printer tank17W of the printer1A toward the server tank6W via the tube82, the point P2, the tube84, and the tube86(refer to arrows B1). When the white ink is returned to the server tank6W from the printer tank17W of the printer1, the white ink flows from the printer tank17W of the printer1B toward the server tank6W via the tube83, the point P3, the tube85, and the tube86(refer to arrows B2).

Both when the white ink is supplied from the server tank6W to the printer tank17W of the printer1A, and when the white ink is returned to the server tank6W from the printer tank17W of the printer1A, the white ink flows through a portion of the tube82further downstream in the supply flow path than the point P2. Both when the white ink is supplied from the server tank6W to the printer tank17W of the printer1i, and when the white ink is returned to the server tank6W from the printer tank17W of the printer1B, the white ink flows through a portion of the tube83further downstream in the supply flow path than the point P3.

By performing one of the supply operation or the return operation after the other operation has been performed, the liquid supply system100can circulate the white ink between the server tank6W and the respective printer tanks17W of the plurality of printers1, via the tubes8. By alternating the supply operations and return operations, the liquid supply system100may circulate the white ink between the server tank6W and the respective printer tanks17W of the plurality of printers1, via the tubes8.

Hereinafter, an operation in which the liquid supply system100circulates the white ink between the server tank6W and the printer tank17W via the tube8will be referred to as a “circulation operation.” The liquid supply system100performs the circulation operation in the first white flow path W1, for example. In this way, the liquid supply system100suppresses the white ink from settling inside the server tank6W and in the first white flow path W1, and in the respective printer tanks of the printers1A and1B.

<Electrical Configuration of Printer1>

As shown inFIG.2, the printer1is provided with a control device40. The control device40is provided with a CPU41, a ROM42, a RAM43, a flash memory44, and a communication portion45. The CPU41controls the printer1, and functions as a processor. The CPU41controls the print processing, for example. The CPU41is electrically connected to the ROM42, the RAM43, the flash memory44, and the communication portion45.

The ROM42stores a control program for the CPU41to control operations of the printer1, information necessary for the CPU41when executing various programs, and the like. The RAM43temporarily stores various data and the like used by the control program. The flash memory44is non-volatile, and stores calibration data of printer sensors185to be described later, and the like. The communication portion45is a controller for communicating, in a wired or wireless manner with an external device. The CPU41communicates with the liquid supply device2, for example, using the communication portion45.

The main scanning motor181, the sub-scanning motor182, the head driver183, the supply mechanism184, the plurality of printer sensors185, and an operation portion186are electrically connected to the CPU41. The main scanning motor181, the sub-scanning motor182, the head driver183, and the supply mechanism184are driven by control of the CPU41.

The printer sensor185is provided in the printer tank17W shown inFIG.1. The printer sensor185is a pressure sensor, for example. The printer sensor185detects a printer remaining amount by detecting a pressure inside the printer tank17W. The printer remaining amount is a remaining amount of the white ink inside the printer tank17W. A signal indicating the printer remaining amount detected by the printer sensor185is output to the CPU41.

The operation portion186is a touch panel display or the like, displays various information, and outputs information to the CPU41in accordance with an operation by the user. By operating the operation portion186, the user can input, to the printer1, a print command for starting printing by the printer1and the like.

<Electrical Configuration of Liquid Supply Device2>

As shown inFIG.3, the liquid supply device2is provided with a control device50. The control device50is provided with a CPU51, a ROM52, a RAM53, a flash memory54, and a communication portion55. The CPU51controls the liquid supply device2, and functions as a processor. The CPU51is electrically connected to the ROM52, the RAM53, the flash memory54, and the communication portion55.

The ROM52stores a control program for the CPU51to control operations of the liquid supply device2, information necessary for the CPU51when executing various programs, and the like. The RAM53temporarily stores various data and the like used by the control program. The flash memory54is non-volatile, and stores calibration data of the server sensors71, and the like. The communication portion55is a controller for communicating, in a wired or wireless manner with an external device. The CPU51communicates with each of the printers1A,1B,1C, and1D, for example, via the communication portion55.

The agitation motor963, the pump motors201,211,261, and271, the solenoids221,231,281, and291, the server sensor71, the display56, and the operation portion57are electrically connected to the CPU51.

The agitation motor963, the pump motors201,211,261, and271, the solenoids221,231,281, and291, and the display56are driven by control of the CPU51. The server sensor71is a weight sensor, for example, and detects a server remaining amount by the weight. The server remaining amount is a remaining amount of the white ink inside the server tank6W. A signal indicating the server remaining amount detected by the server sensor71is output to the CPU51.

In the present embodiment, oscillation may occur in the white ink inside the server tank6W due to the circulation operation, or a minute amount of the white ink may flow from one to the other of the server tank6W and the tube8after the end of the circulation operation. In this case, there is a possibility that an error may occur between the server remaining amount detected by the server sensor71and the actual server remaining amount.

Similarly, oscillation may occur in the white ink inside the printer tank17W due to the circulation operation, or a minute amount of the white ink may flow from one to the other of the printer tank17W and the tube8after the circulation operation. In this case, there is a possibility that an error may occur between the printer remaining amount detected by the printer sensor185and the actual printer remaining amount.

When the above-described error occurs, there is a possibility that the actual server remaining amount after the circulation operation may change from the server remaining amount before the circulation operation, and that the actual printer remaining amount after the circulation operation may change from the printer remaining amount before the circulation operation. For example, in the present embodiment, the actual server remaining amount after the circulation operation may decrease from the server remaining amount before the circulation operation, and the actual printer remaining amount after the circulation operation may increase from the printer remaining amount before the circulation operation. In this case, as a result of repeatedly performing the circulation operation, there is a possibility that the white ink may overflow from the printer tank17W. In the present embodiment, by performing main processing to be described below, the liquid supply system100contributes to suppressing the white ink from overflowing from the printer tank17W.

When a power supply to the liquid supply device2is turned on, for example, the CPU51performs the main processing shown inFIG.4, by reading out and executing the control program from the ROM52. In the main processing, the CPU51performs control relating to the supply operation and the return operation. In the main processing, the control relating to the supply operation and the return operation is performed for the second white flow path W2in a similar manner as for the first white flow path W1. In the present embodiment, with respect to the main processing, the control relating to the first white flow path W1will be described and a description of the control relating to the second white flow path W2will be omitted. Hereinafter, the description will be made assuming that, at the start of the main processing, all of the supply valves22and23and the circulation valves28and29shown inFIG.1are in the closed state.

As shown inFIG.4, when the main processing is started, the CPU51determines whether or not a supply request for performing supply processing (S13) to be described later has been acquired from the printer1A or the printer1B (S12). For example, when the printer1A performs the print processing using the white ink, the white ink in the printer tank17W of the printer1A is consumed and the printer remaining amount of the printer1A decreases. For example, in the printer1A, when the printer remaining amount has become equal to or less than a predetermined supply start remaining amount, the CPU41transmits the supply request to the liquid supply device2. The supply start remaining amount is stored in advance in the flash memory44, for example.

When the supply request has not been acquired from either the printer1A or the printer1B (no at S12), the CPU51shifts the processing to S14. When the supply request has been received from the printer1A or the printer1B (yes at S12), the CPU51performs the supply processing (S13).

In the supply processing (S13), the CPU51controls the supply operation for the printer tank17W of the printer1from which the supply request has been acquired. For example, when the supply request has been acquired from the printer1A, the CPU51controls the solenoid221shown inFIG.3in the supply operation, and causes the supply valve22shown inFIG.1to be in the open state. In this state, the CPU51controls the pump motor201shown inFIG.3, and starts the driving of the supply pump20shown inFIG.1. In this way, the white ink is supplied from the server tank6W to the printer tank17W of the printer1A, via the tube8.

When, for example, the printer remaining amount has reached a predetermined supply stop remaining amount as a result of the supply operation, the CPU41transmits a supply stop request to the liquid supply device2. The supply stop remaining amount is stored in advance in the flash memory44, for example. The supply stop remaining amount is greater than the supply start remaining amount, for example. When the supply stop request has been acquired from the printer1A, for example, the CPU51stops the driving of the pump motor201shown inFIG.3, and stops the driving of the supply pump20shown inFIG.1. The CPU51controls the solenoid221shown inFIG.3and causes the supply valve22shown inFIG.1to be in the closed state. In this way, the CPU51stops the supply operation and ends the supply processing.

The CPU51refers to the timer counter in the RAM53, and determines whether or not a circulation interval has elapsed (S14) for each of the printers1A and1B. In the present embodiment, circulation processing (S60, refer toFIG.5) to be described later is periodically performed for the printer tank17W of each of the printers1A and1B. First circulation processing and second circulation processing will be defined. The first circulation processing is one of the circulation processing that is periodically performed. The second circulation processing is the circulation processing subsequent to the first circulation processing, of the circulation processing that is periodically performed. The circulation interval is a time period between the first circulation processing and the second circulation processing, and is stored in advance in the flash memory54, for example. The circulation interval is not limited to a specific length, and is 4 hours, for example.

When the circulation interval has not elapsed (no at S14) for either of the printers1A and1i, the CPU51returns the processing to S12. Hereinafter, the printer1in which the circulation interval has elapsed will be referred to as a “target printer.” When the circulation interval has elapsed (yes at S14) in the printer1A or the printer1B, the CPU51acquires the printer remaining amount from the printer sensor185of the target printer (S21).

In the processing at S21, for example, the CPU51transmits, to the target printer, a remaining amount request for requesting the printer remaining amount from the target printer. In the target printer, when the CPU41receives the remaining amount request, the CPU41transmits the printer remaining amount indicated by the signal from the printer sensor185to the liquid supply device2. The CPU51acquires the printer remaining amount transmitted from the target printer.

The CPU51determines whether or not the printer remaining amount of the target printer acquired by the processing at S21is equal to or greater than a printer prescribed remaining amount (S22). The printer prescribed remaining amount is less than the difference between a printer maximum increase amount and a capacity of the printer tank17W, and in the present embodiment, is greater than the supply start remaining amount and greater than the supply stop remaining amount. The printer maximum increase amount is the difference between the printer remaining amount at a start of the circulation processing to be described later, and a maximum printer remaining amount in a period from the start to the end of the circulation processing. The capacity of the printer tank17W is a maximum value of the amount of white ink stored inside the printer tank17W, when the white ink does not overflow from the printer tank17W during normal usage of the printer tank17W. Normal usage of the printer tank17W means that the printer tank17W is used when placed on a horizontal surface, that the printer tank17W is used when mounted to a mounting portion (not shown in the drawings) for mounting the printer tank17W, or the like. For example, when an inlet opening is provided for pouring the ink into the printer tank17W, the capacity of the printer tank17W may be determined as a volume of the lower portion of the printer tank17W lower than a position of the lower edge of the inlet opening in the up-down direction. The printer prescribed remaining amount is stored in advance in the flash memory54, for example.

In the target printer, for example, when an execution frequency of the print processing using the white ink from the time the circulation processing was previously performed is high, the printer remaining amount is decreased from the time the circulation processing was previously performed, and thus, the printer remaining amount is more likely to be less than the printer prescribed remaining amount. When the printer remaining amount is less than the printer prescribed remaining amount (no at S22), the CPU51performs the circulation processing shown inFIG.5(S60). After the circulation processing, the CPU51returns the processing to S12.

The circulation processing (S60) will be described in detail with reference toFIG.6. In the circulation processing, the CPU51controls the circulation operation for the printer tank17W of the target printer. When the circulation processing is started, the CPU51acquires the server remaining amount from the server sensor71shown inFIG.3(S61). The CPU51stores the server remaining amount acquired by the processing at S61in the RAM53, as a pre-circulation remaining amount (S62). The pre-circulation remaining amount is the server remaining amount at the start of the circulation operation, and in the present embodiment, is the server remaining amount at the start of the supply operation in processing at S63to be described below.

The CPU51starts the supply operation for the printer tank17W of the target printer (S63). For example, when the target printer is the printer1A, in the processing at S63, the CPU51controls the solenoid221shown inFIG.3and causes the supply valve22shown inFIG.1to be in the open state. In this state, the CPU51controls the pump motor201shown inFIG.3and starts the driving of the supply pump20shown inFIG.1. In this way, the white ink is supplied from the server tank6W to the printer tank17W of the printer1A (the target printer), via the tube8.

The CPU51refers to the timer counter in the RAM53, and determines whether or not a supply time period has elapsed (S64). The supply time period is a time period from the start to the end of the supply operation, and is stored in advance in the flash memory54, for example.

When the supply time period has not elapsed (no at S64), the CPU51repeats the processing at S64until the supply time period has elapsed. When the supply time period has elapsed (yes at S64), the CPU51stops the supply operation for the printer tank17W of the target printer (S65). In the processing at S65, the CPU51stops the driving of the pump motor201shown inFIG.3, and stops the driving of the supply pump20shown inFIG.1. The CPU51controls the solenoid221shown inFIG.3and causes the supply valve22shown inFIG.1to be in the closed state. In this way, the supply of the white ink from the server tank6W to the printer tank17W of the printer1A (the target printer) via the tube8is stopped.

The CPU51starts the return operation for the printer tank17W of the target printer (S71). For example, when the target printer is the printer1A, in the processing at S71, the CPU51controls the solenoid281shown inFIG.3, and causes the circulation valve28shown inFIG.1to be in the open state. In this state, the CPU51controls the pump motor261shown inFIG.3and starts the driving of the circulation pump26shown inFIG.1. In this way, the white ink is returned from the printer tank17W of the printer1A (the target printer) to the server tank6W via the tube8.

The CPU51acquires the server remaining amount from the server sensor71shown inFIG.3(S72). The CPU51determines whether or not the server remaining amount acquired by the processing at S72has reached the pre-circulation remaining amount stored by the processing at S62(S73). When the server remaining amount has not reached the pre-circulation remaining amount (no at S73), the CPU51returns the processing to S72.

When the server remaining amount has reached the pre-circulation remaining amount (yes at S73), the CPU51stops the return operation for the printer tank17W of the target printer (S74). In the processing at S74, for example, the CPU51stops the driving of the pump motor261shown inFIG.3, and stops the driving of the circulation pump26shown inFIG.1. The CPU51controls the solenoid281shown inFIG.3and causes the circulation valve28shown inFIG.1to be in the closed state. In this way, the returning of the white ink from the printer tank17W of the printer1A (the target printer) to the server tank6W via the tube8is stopped. The CPU51returns the processing to the main processing shown inFIG.5.

In the processing at S22shown inFIG.4, when the printer remaining amount is equal to or greater than the printer prescribed remaining amount (yes at S22), the CPU51acquires the server remaining amount from the server sensor71shown inFIG.3(S23). The CPU51determines whether or not the server remaining amount acquired by the processing at S23is equal to or greater than a server prescribed remaining amount (S24). The server prescribed remaining amount is less than the difference between a server maximum increase amount and a capacity of the server tank6W. The server maximum increase amount is the difference between the server remaining amount at the start of the circulation processing (the pre-circulation remaining amount), and a maximum server remaining amount in a period from the start to the end of the circulation processing. When the maximum server remaining amount from the start to the end of the circulation processing is not greater than the server remaining amount at the start of the circulation processing, that is, when the server remaining amount does not increase, during the circulation processing, from the server remaining amount at the start of the circulation processing, the server maximum increase amount is “zero.” More specifically, as will be described later with reference toFIG.7, in the present embodiment, the server maximum increase amount is “zero.” Thus, it is sufficient that the server prescribed remaining amount be less than the capacity of the server tank6W. The server prescribed remaining amount is stored in advance in the flash memory54, for example. The capacity of the server tank6W is a maximum value of the amount of white ink stored inside the server tank6W, when the white ink does not overflow from the server tank6W during normal usage of the server tank6W. Normal usage of the server tank6W means that the server tank6W is used when placed on a horizontal surface, that the server tank6W is used when mounted to a mounting portion (not shown in the drawings) for mounting the server tank6W, or the like. For example, when an inlet opening is provided for pouring the ink into the server tank6W, the capacity of the server tank6W may be determined as a volume of the lower portion of the server tank6W lower than a position of the lower edge of the inlet opening in the up-down direction.

When the server remaining amount is less than the server prescribed remaining amount (no at S24), the CPU51shifts the processing to step S51shown inFIG.5. When the server remaining amount is equal to or greater than the server prescribed remaining amount (yes at S24), the CPU51acquires the printer remaining amounts from the printer sensor185of others of the printers1(S31). The other printers1are, of the plurality of printers1, the printers1other than the target printer, and are two or more of the printers1. For example, when the target printer is the printer1A, the other printers are the printers1B,1C, and1D.

The CPU51determines, based on each of the printer remaining amounts acquired by the processing at S31, whether or not there is the printer tank17W in which the printer remaining amount is less than the printer prescribed remaining amount, among each of the printer tanks17W of the other printers1(S32). When there is no printer tank17W in which the printer remaining amount is less than the printer prescribed remaining amount (no at S32), the liquid supply system100is in an error state, and the CPU51performs error notification (S33). In this case, the CPU51returns the processing to S12without performing the circulation processing (S60) shown inFIG.5and first liquid delivery processing to be described later (S51to S54).

For example, if a user fills the server tank6W with white ink such that the server remaining amount is equal to or greater than the server prescribed remaining amount, in a state in which the printer remaining amounts of each of the plurality of printers1is equal to or greater than the printer prescribed remaining amount, the liquid supply system100is in an error state. The error notification is not limited to a specific format, and the CPU51performs error display on the display56shown inFIG.3, for example, and causes a warning lamp (not shown in the drawings) to be illuminated. For example, when the printing processing that uses the white ink is performed in any one of the plurality of printers1, the printer remaining amount falls. The error may be cancelled when the printer remaining amount in any one of the plurality of printers1becomes less than the printer prescribed remaining amount. The error may be cancelled when the printer remaining amount of the target printer has become less than the printer prescribed remaining amount.

In the processing at S32, when there is the printer tank17W in which the printer remaining amount is less than the printer prescribed remaining amount (yes at S32), the CPU51shifts the processing to S40shown inFIG.5.

As shown inFIG.5, based on the printer remaining amounts of the other printers1acquired by the processing at S31, the CPU51identifies a minimum printer tank from among the printer tanks17W in which the printer remaining amount is less than the printer prescribed remaining amount (S40). The minimum printer tank is the printer tank17W, of the printer tanks17W in which the printer remaining amount is less than the printer prescribed remaining amount, in which the printer remaining amount is the least.

The CPU51starts the supply operation for the minimum printer tank identified by the processing at S40(S41). For example, when the minimum printer tank is the printer tank17W of the printer1B, in the processing at S41, the CPU51controls a solenoid231shown inFIG.3and causes the supply valve23shown inFIG.1to be in the open state. In this state, the CPU51controls the pump motor211shown inFIG.3, and starts the driving of the supply pump21shown inFIG.1. In this way, the white ink is supplied from the server tank6W to the printer tank17W of the printer1B (the minimum printer tank), via the tube8. In this case, the white ink is not supplied to the printer tank17W of the target printer (the printer1A, for example).

The CPU51acquires the server remaining amount from the server sensor71shown inFIG.3(S42). The CPU51determines whether or not the server remaining amount acquired by the processing at S42has become less than the server prescribed remaining amount (S43). When the server remaining amount is equal to or greater than the server prescribed remaining amount (no at S43), the CPU51returns the processing to S42.

When the server remaining amount has become less than the server prescribed remaining amount (yes at S43), the CPU51stops the supply operation for the minimum printer tank (S44). In the processing at S44, for example, the CPU51stops the driving of the pump motor211shown inFIG.3, and stops the driving of the supply pump21shown inFIG.1. The CPU51controls the solenoid231shown inFIG.3and causes the supply valve23shown inFIG.1to be in the closed state. In this way, the supply of the white ink from the server tank6W to the printer tank17W of the printer1B (the minimum printer tank) via the tube8is stopped.

After the processing at S44, or in the processing at S24shown inFIG.4, when the server remaining amount becomes less than the server prescribed remaining amount (no at S24), in a similar manner to the processing at S71shown inFIG.6, the CPU51starts the return operation for the printer tank17W of the target printer (S51). In this way the white ink is returned to the server tank6W from the printer tank17W of the printer1A (the target printer), via the tube8.

The CPU51acquires the printer remaining amount from the printer sensor185of the target printer (S52). The CPU51determines whether or not the printer remaining amount acquired by the processing at S52has reached a return remaining amount (S53). The return remaining amount is the printer remaining amount at the end of the return operation, and is less than the difference between the printer prescribed remaining amount and the printer maximum increase amount. The return remaining amount is stored in advance in the flash memory54, for example.

When the printer remaining amount is greater than the return remaining amount (no at S53), the CPU51returns the processing to S52. When the printer remaining amount has reached the return remaining amount (yes at S53), the CPU51stops the return operation for the printer tank17W of the target printer (S54). In this way, the returning of the white ink from the printer tank17W of the printer1A (the target printer) to the server tank6W via the tube8is stopped. The CPU51performs the circulation processing (S60), and returns the processing to S12shown inFIG.4.

Hereinafter, the processing from S51to S54will be referred to as “first liquid delivery processing,” and the amount of white ink delivered by the first liquid delivery processing from the printer tank17W of the target printer to the server tank6W via the tube8will be referred to as a “return amount.”

The return amount will be described. The return amount is the difference between the printer remaining amount of the target printer at the start of the first liquid delivery processing and the printer remaining amount (the return remaining amount) of the target printer at the end of the first liquid delivery processing. The first liquid delivery processing is performed when the printer remaining amount of the target printer is equal to or greater than the printer prescribed remaining amount. Thus, the printer remaining amount of the target printer at the start of the first liquid delivery processing is equal to or greater than the printer prescribed remaining amount. Furthermore, the first liquid delivery processing is stopped when the printer remaining amount of the target printer has reached the return remaining amount. Thus, the printer remaining amount of the target printer at the end of the first liquid delivery processing is the return remaining amount. In this way, the printer remaining amount of the target printer at the end of the first liquid delivery processing is a constant value that is the return remaining amount, and a minimum value of the printer remaining amount of the target printer at the start of the first liquid delivery processing is the printer prescribed remaining amount, and thus, a minimum value of the return amount is the difference between the printer prescribed remaining amount and the return remaining amount. The return remaining amount is less than the difference between the printer prescribed remaining amount and the printer maximum increase amount. Thus, the return amount is greater than the printer maximum increase amount. In this case, the circulation processing is performed after the first liquid delivery processing, and even if the printer remaining amount increases from the return remaining amount by an amount corresponding to the printer maximum increase amount, the printer remaining amount is suppressed from becoming equal to or greater than the printer prescribed remaining amount. As a result, the white ink is suppressed from overflowing from the printer tank17W of the target printer during the circulation processing.

<Transitions in Remaining Amounts of White Ink>

An example of transitions in the server remaining amount and the printer remaining amount of the target printer will be described with reference toFIG.7andFIG.8. Hereinafter, a case is assumed in which, when the circulation interval has elapsed (yes at S14), the printer remaining amount of the target printer is equal to or greater than the printer prescribed remaining amount (yes at S22), the server remaining amount is equal to or greater than the server prescribed remaining amount (yes at S24), and there is the printer tank17W of the other printer1in which the printer remaining amount is less than the printer prescribed remaining amount (yes at S32).

As shown inFIG.7, a state ST11shows the server tank6W when the circulation interval has elapsed. Thus, a remaining amount V11is the server remaining amount when the circulation interval has elapsed. A remaining amount V10is the server prescribed remaining amount. The remaining amount V11is greater than the remaining amount V10(the server prescribed remaining amount).

As shown inFIG.8, a state ST21shows the printer tank17W of the target printer when the circulation interval has elapsed. Thus, a remaining amount V21is the printer remaining amount of the target printer when the circulation interval has elapsed. A remaining amount V20is the printer prescribed remaining amount. The remaining amount V21is greater than the remaining amount V20(the printer prescribed remaining amount).

As shown inFIG.7, when the supply operation is performed for the minimum printer tank by the processing from S41to S44shown inFIG.5(hereinafter referred to as “second liquid delivery processing”), the server remaining amount decreases, by an amount corresponding to an amount V12, from the remaining amount V11shown by the state ST11to a remaining amount V13shown by a state ST12. The remaining amount V13is less than the server prescribed remaining amount (the remaining amount V10). Note that even if the supply operation has been performed for the minimum printer tank by the second liquid delivery processing, the printer remaining amount of the target printer does not change, and thus, the printer tank17W of the target printer does not change from the state ST21shown inFIG.8.

When the return operation is performed for the printer tank17W of the target printer by the first liquid delivery processing (S51to S54) shown inFIG.5, the server remaining amount increases, by an amount corresponding to an amount V14, from the remaining amount V13shown by the state ST12to a remaining amount V15shown by a state ST13. The amount V14is the return amount. InFIG.7, the remaining amount V15is greater than the remaining amount V10(the server prescribed remaining amount). In contrast to this, the remaining amount V15may be equal to or less than the remaining amount V10, depending on a relationship with the remaining amount V13and the amount V14.

As shown inFIG.8, when the return operation is performed for the printer tank17W of the target printer by the first liquid delivery processing (S51to S54) shown inFIG.5, the printer remaining amount of the target printer decreases, by an amount corresponding to an amount V22, from the remaining amount V21shown by the state ST21to a remaining amount V23shown by a state ST22. The amount V22is the return amount. The remaining amount V23is the return remaining amount.

As shown inFIG.7, when the supply operation is performed for the printer tank17W of the target printer by the processing at S63to S65shown inFIG.6, the server remaining amount decreases, by an amount corresponding to an amount V16, from the remaining amount V15shown by the state ST13to a remaining amount V17shown by a state ST14. In the present embodiment, the amount V16is an amount of the white ink corresponding to the supply time period.

As shown inFIG.8, when the supply operation is performed for the printer tank17W of the target printer by the processing at S63to S65shown inFIG.6, the printer remaining amount of the target printer increases, by an amount corresponding to an amount V24, from the remaining amount V23shown by the state ST22to a remaining amount V25shown by a state ST23. In the present embodiment, during a period from the start to the end of the circulation processing, the printer remaining amount does not exceed the remaining amount V25of the circulation processing. Thus, the amount V24is the printer maximum increase amount, and in the present embodiment, is the amount of the white ink corresponding to the supply time period.

As shown inFIG.7, when the return operation is performed for the printer tank17W of the target printer by the processing at S71to S74shown inFIG.6, the server remaining amount increases, by an amount corresponding to an amount V18, from the remaining amount V17shown by the state ST14to a remaining amount V19shown by a state ST15. In the present embodiment, in the circulation processing, the supply operation is performed before the return operation. Furthermore, as described above, due to a detection error by the server sensor71at the end of the circulation processing, or the like, the actual amount V16of the white ink supplied from the server tank6W to the printer tank17W of the target printer via the tube8by the supply operation is less than the actual amount V18of the white ink returned from the printer tank17W of the target printer to the server tank6W via the tube8by the return operation. Thus, the CPU51at S73determines whether or not the server remaining amount acquired by the processing at S72has reached the pre-circulation remaining amount stored by the processing at S62, but in actuality, during a period from the start to the end of the circulation processing, the server remaining amount does not exceed the remaining amount V15at the start of the circulation processing. Thus, the server maximum increase amount is “zero.” For example, in the circulation processing, when the return operation is performed before the supply operation, the server maximum increase amount becomes the amount of the white ink supplied from the server tank6W to the printer tank17W of the target printer via the tube8by the supply operation, and becomes greater than “zero.”

As shown inFIG.8, when the return operation is performed for the printer tank17W of the target printer by the processing at S71to S74shown inFIG.6, the printer remaining amount of the target printer decreases, by an amount corresponding to an amount V26, from the remaining amount V25shown by the state ST23, to a remaining amount V28shown by a state ST24. Note that the return operation is stopped by the processing at S74when the server remaining amount reaches the pre-circulation remaining amount. However, as described above, due to a detection error by the server sensor71at the end of the circulation processing, or the like, in the state ST24, the actual printer remaining amount of the target printer may become the remaining amount V28that is greater than the remaining amount V23by an amount corresponding to an amount V27.

Note that, when the circulation interval has elapsed, if the printer remaining amount of the target printer is equal to or greater than the printer prescribed remaining amount and the server remaining amount is less than the server prescribed remaining amount, the printer remaining amount of the target printer transitions from the state ST21shown inFIG.8in a similar manner to the transitions described above. In this case, the server remaining amount transitions from the state ST12shown inFIG.7. When the circulation interval has elapsed, if the printer remaining amount of the target printer is less than the printer prescribed remaining amount, the printer remaining amount of the target printer transitions from the state ST22shown inFIG.8. In this case, the server remaining amount transitions from the state ST13shown inFIG.7.

Effects of Embodiment

In the above-described embodiment, the liquid supply system100supplies the white ink to the printer tank17W provided in the printer1. The tube8connects the printer tank17W and the server tank6W storing the white ink. The supply pumps20and21, the supply valves22and23, the circulation pumps26and27, and the circulation valves28and29(hereinafter referred to as a “liquid delivery mechanism”) are provided in the tube8, and perform the supply operation of supplying the white ink from the server tank6W to the printer tank17W via the tube8, and the return operation of returning the white ink from the printer tank17W to the server tank6W via the tube8. In the circulation processing (S60), the CPU51causes the liquid delivery mechanism to perform the supply operation and the return operation. When the printer remaining amount has become equal to or greater than the printer prescribed remaining amount, before the circulation processing (S60), in the first liquid delivery processing (S51to S54), the CPU51causes the liquid delivery mechanism to perform the return operation that delivers the white ink from the printer tank17W to the server tank6W via the tube8.

According to this configuration, when the printer remaining amount becomes equal to or greater than the printer prescribed remaining amount, before the circulation processing, the white ink is delivered from the printer tank17W to the server tank6W by the first liquid delivery processing. In this way, the printer remaining amount decreases. Thus, even when the circulation processing is subsequently performed, the white ink is suppressed from overflowing from the printer tank17W. As a result, the CPU51contributes to suppressing the white ink from overflowing from the printer tank17W.

The CPU51performs the first liquid delivery processing and the circulation processing in that order for the target printer when the circulation interval has elapsed, and the printer remaining amount of the target printer is equal to or greater than the printer prescribed remaining amount. Thus, the CPU51contributes to shortening a down time caused by the first liquid delivery processing, compared to a case in which the first liquid delivery processing is separately performed without regard to the circulation processing.

The printer prescribed remaining amount is less than the difference between the printer maximum increase amount and the capacity of the printer tank17W. The printer maximum increase amount is the difference between the printer remaining amount at the start of the circulation processing and the maximum remaining amount of the white ink in the printer tank17W from the start to the end of the circulation processing. For example, in a state in which the printer remaining amount is slightly less than the printer prescribed remaining amount, the first liquid delivery processing is not performed. Even in this case, since the printer prescribed remaining amount is less than the difference between the printer maximum increase amount and the capacity of the printer tank17W, even if the printer remaining amount increases by an amount corresponding to the printer maximum increase amount as a result of the circulation processing, the increased printer remaining amount is suppressed from reaching the capacity of the printer tank17W. Thus, the liquid supply system100contributes to further suppressing the white ink from overflowing from the printer tank17W.

The amount of the white ink delivered from the printer tank17W to the server tank6W via the tube8by the return operation in the first liquid delivery processing (the return amount) is greater than the printer maximum increase amount. According to this configuration, even when the first liquid delivery processing is performed after the circulation processing, the printer remaining amount is suppressed from becoming equal to or greater than the printer prescribed remaining amount as a result of the circulation processing. Thus, the liquid supply system100contributes to reducing an execution frequency of the first liquid delivery processing.

When the printer remaining amount is equal to or greater than the printer prescribed remaining amount and the server remaining amount is equal to or greater than the server prescribed remaining amount, the CPU51prohibits the execution of the first liquid delivery processing and the circulation processing. According to this configuration, the white ink is suppressed from overflowing from the server tank6W as a result of the first liquid delivery processing. Thus, the CPU51contributes to suppressing the white ink from overflowing from the server tank6W, in addition to the printer tank17W.

When the printer remaining amount of the target printer is equal to or greater than the printer prescribed remaining amount, and the server remaining amount is equal to or greater than the server prescribed remaining amount, before the first liquid delivery processing, in the second liquid delivery processing, the CPU51causes the liquid delivery mechanism to perform the supply operation that supplies the white ink from the server tank6W to the printer tanks17W of the other printers1via the tube8, until the server remaining amount becomes less than the server prescribed remaining amount. According to this configuration, the white ink is returned to the server tank6W from the printer tank17W of the target printer via the tube8by the first liquid delivery processing in the state in which the server remaining amount has become less than the server prescribed remaining amount. Thus, the CPU51contributes to suppressing the white ink from overflowing from the server tank6W, in addition to the printer tank17W.

In the second liquid delivery processing, the CPU51causes the liquid delivery mechanism to perform the supply operation that supplies the white ink from the server tank6W to the minimum printer tank, in which the printer remaining amount is the least, via the tube8. According to this configuration, the CPU51contributes to increasing the printer remaining amount of the minimum printer tank, by suppling the white ink to the minimum printer tank. For example, even if the server tank6W is unable to supply the white ink to each of the printer tanks17W of the plurality of printers1, due to a malfunction of the liquid supply device2or the like, by supplying the white ink in advance to the minimum printer tank in the second liquid delivery processing, a quantity of the print medium that can be printed by the printer1that is the minimum printer tank increases. Thus, the CPU51contributes to suppressing a down time of the printer1when the liquid supply device2malfunctions or the like.

Modified Examples

While the invention has been described in conjunction with various example structures outlined above and illustrated in the figures, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or that may be presently unforeseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the example embodiments of the disclosure, as set forth above, are intended to be illustrative of the invention, and not limiting the invention. Various changes may be made without departing from the spirit and scope of the disclosure. Therefore, the disclosure is intended to embrace all known or later developed alternatives, modifications, variations, improvements, and/or substantial equivalents. Some specific examples of potential alternatives, modifications, or variations in the described invention are provided below. Modified examples described below may be combined with each other as appropriate insofar as no contradictions arise. In the above-described embodiment, when the circulation interval has elapsed, the CPU51acquires the printer remaining amount of the target printer in the processing at S21. In contrast to this, the CPU51may acquire the printer remaining amounts of each of the plurality of printers1, regardless of whether or not the circulation interval has elapsed. For example, when the printer remaining amount of any one of the plurality of printers1has become equal to or greater than the printer prescribed remaining amount, the CPU51may perform the processing from S23onward without waiting for the circulation interval to elapse. In this case, if the printer remaining amounts of all of the plurality of printers1are less than the printer prescribed remaining amount, the CPU51may return the processing to S12.

As long as the printer prescribed remaining amount is less than the capacity of the printer tank17W, the printer prescribed remaining amount may be the same as the difference between the printer maximum increase amount and the capacity of the printer tank17W, or may be greater than the difference between the printer maximum increase amount and the capacity of the printer tank17W. The return amount may be the same as the printer maximum increase amount, or may be greater than the printer maximum increase amount. The printer prescribed remaining amount may be the same as the supply start remaining amount, or may be less than the supply start remaining amount. The printer prescribed remaining amount may be the same as the supply stop remaining amount, or may be less than the supply stop remaining amount.

In the above-described embodiment, when the server remaining amount increases as a result of the circulation processing, in the processing at S22, the CPU51may determine whether or not the server remaining amount has become equal to or greater than the server prescribed remaining amount. In this case, if the server remaining amount is equal to or greater than the server prescribed remaining amount (yes at S22), the CPU51may omit the second liquid delivery processing, and, in the first liquid delivery processing, may cause the liquid delivery mechanism to perform the supply operation to deliver the white ink from the server tank6W to the printer tank17W of the target printer via the tube8. In this case, the CPU51may perform the circulation processing after the first liquid delivery processing. Hereinafter, a modified example in which, in the first liquid delivery processing, the CPU51causes the liquid delivery mechanism to perform the supply operation to deliver the white ink from the server tank6W to the printer tank17W via the tube8will be referred to as a “modified example of the first liquid delivery processing.” In the modified example of the first liquid delivery processing, since the server remaining amount has decreased before the circulation processing, the CPU51contributes to suppressing the white ink from overflowing from the server tank6W.

In the modified example of the first liquid delivery processing, the amount of the white ink delivered by the first liquid delivery processing from the server tank6W to the printer tank17W of the target printer via the tube8will be referred to as a “supply amount.” The supply amount is preferably greater than the server maximum increase amount, but may be the same as the server maximum increase amount or may be less than the server maximum increase amount.

The server prescribed remaining amount is preferably less than the difference between the server maximum increase amount and the capacity of the server tank6W, but as long as the server prescribed remaining amount is less than the capacity of the server tank6W, the server prescribed remaining amount may be the same as the difference between the server maximum increase amount and the capacity of the server tank6W, or may be greater than the difference between the server maximum increase amount and the capacity of the server tank6W.

In the above-described embodiment, the CPU51may omit the second liquid delivery processing. In other words, in the processing at S24, when the server remaining amount is equal to or greater than the server prescribed remaining amount, the CPU51may perform the error notification without determining whether or not there is the printer tank17W in which the printer remaining amount is equal to or less than the printer prescribed remaining amount. When the printer remaining amount is equal to or greater than the printer prescribed remaining amount, and the server remaining amount is equal to or greater than the server prescribed remaining amount, the CPU51may perform one or both of the first liquid delivery processing and the circulation processing. In the processing at S22, when the printer remaining amount is equal to or greater than the printer prescribed remaining amount, the CPU51may shift the processing to the first liquid delivery processing without performing the determinations at S24and S32.

In the processing at S40, the CPU51need not necessarily identify the minimum printer tank. For example, the CPU51may identify the printer tank17W of the printer1that is determined in advance. The CPU51may identify the printer tank17W in which an empty capacity is greatest. The CPU51may identify the printer tank17W having the highest frequency for performing the supply processing.

The CPU51may control the supply processing, the first liquid delivery processing, the second liquid delivery processing, the circulation processing, and the like based on the signal from the server sensor71, or based on the signal from the printer sensor185. For example, in the circulation processing, in the processing at S61, the CPU51may acquire the printer remaining amount from the printer sensor185, and, in the processing at S62, may store the printer remaining amount in the RAM53as the pre-circulation remaining amount. In this case, in the processing at S72, the CPU51may acquire the printer remaining amount from the printer sensor185, and, in the processing at S73, may determine whether or not the printer remaining amount has reached the pre-circulation remaining amount.

In the circulation processing, the CPU51may change an execution order of the supply operation (S63and S65) and the return operation (S71and S74). For example, the CPU51may perform the supply operation after performing the return operation. The CPU51may perform the supply operation and the return operation in parallel with each other. The CPU51may alternately repeat the supply operation and the return operation.

In the above-described embodiment, when the supply time period has elapsed (yes at S64), the CPU51stops the supply operation (S65). In contrast to this, the CPU51may stop the supply operation based on an integrated number of rotations of the supply pumps20and21from when the supply operation is started by the processing at S63, on a change amount of the server remaining amount from when the supply operation is started by the processing at S43, or the like. The CPU51may control the supply operation and the return operation based on the printer remaining amount.

In the above-described embodiment, when the server remaining amount has reached the pre-circulation remaining amount (yes at S73), the CPU51stops the return operation (S74). In contrast to this, the CPU51may stop the return operation based on an integrated number of rotations of the circulation pumps26and27from when the return operation is started by the processing at S71, on a change amount of the server remaining amount from when the return operation is started by the processing at S71, or the like.

For example, in the first white flow path W1, the liquid supply device2may omit one or both of the supply pumps20and21. For example, when both the supply pumps20and21are omitted, the CPU51controls one or both of the supply valves22and23to be in the open state and the closed state. In this way, the CPU51may control the supply of the white ink to the respective printer tanks17W of the printers1A and1B from the server tank6W using the liquid head difference between the respective printer tanks17W of the printers1A and1B and the server tank6W.

For example, in the first white flow path W1, the liquid supply device2may omit one or both of the circulation pumps26and27. For example, when both the circulation pumps26and27are omitted, the CPU51controls one or both of the circulation valves28and29to be in the open state and the closed state. In this way, the CPU51may control the return of the white ink from the respective printer tanks17W of the printers1A and1B to the server tank6W using the liquid head difference between the respective printer tanks17W of the printers1A and1B and the server tank6W.

For example, in the first white flow path W1, the liquid supply device2may omit one or both of the supply valves22and23. In the first white flow path W1, the liquid supply device2may omit one or both of the circulation valves28and29. In the first white flow path W1, the liquid supply device2may omit one or both of the filters24and25.

In the tube82, for example, the liquid supply device2may change an upstream or downstream positional relationship in the supply flow path of the supply pump20, the supply valve22, and the filter24, as appropriate. Similarly, in the tube83, for example, the liquid supply device2may change an upstream or downstream positional relationship in the supply flow path of the supply pump21, the supply valve23, and the filter25, as appropriate.

In the tube84, for example, the liquid supply device2may change an upstream or downstream positional relationship in the circulation flow path of the circulation pump26and the circulation valve28, as appropriate. Similarly, in the tube85, for example, the liquid supply device2may change an upstream or downstream positional relationship in the circulation flow path of the circulation pump27and the circulation valve29, as appropriate.

The single printer1may be connected to the single liquid supply device2by the tube8. The two printers1, three printers 1 or more than five printers1may be connected to the single liquid supply device2by the tube8. The liquid supply device2may be provided with only the server tank6W of the plurality of server tanks, and need not necessarily be provided with the other server tanks. In this case, the printer1may be provided with only the printer tank17W for example, of the plurality of printer tanks, and need not necessarily be provided with the other printer tanks. The printer1need not necessarily be provided with the other heads.

The liquid supply system100may supply a pre-treatment agent, a post-treatment agent, or water, as the liquid, to each of the plurality of printers1from the liquid supply device2. For example, the water may be used for humidifying the atmosphere inside the printer1. In this case, the plurality of printers1may be respectively provided with a humidifier. The humidifier is provided inside the printer1and humidifies the atmosphere inside the printer1. The tube8may connect the server tank storing the water and a tank of the humidifier with each other. The main processing may be applied to a flow path of the water instead of, or in addition to, the first white flow path W1and the second white flow path W2. Similarly, the main processing may be applied to a flow path of the color inks, the pre-treatment agent, or the post-treatment agent, for example.

The configuration of the printer1is not limited to that of the above-described embodiment. For example, in the above-described embodiment, the printer1may be a type different from the inkjet printer, and may be a laser printer, a tape printer, or the like. The plurality of heads14are not limited to the inkjet heads, and may be thermal heads, or the like. The head14and the other heads may be a line head. For example, the printer1need not necessarily use ink as the liquid, and it is sufficient that the printer1be provided with the humidifier. In this case, the liquid supply system100supplies the water from the liquid supply device2to the humidifier of the printer1via the tube8.

The server sensor71may be an optical sensor or an electrode-type level sensor. In this case, the server sensor71may detect the server remaining amount by detecting a height of the liquid surface inside the server tank6W. The server sensor71may be a pressure sensor. In this case, the server sensor71may detect the server remaining amount by detecting the pressure inside the server tank6W.

The printer sensor185may be a weight sensor. In this case, the printer sensor185may detect the printer remaining amount by detecting the weight of the printer remaining amount. The printer sensor185may be an optical sensor or an electrode-type level sensor. In this case, the printer sensor185may detect the printer remaining amount by detecting a height of the liquid surface inside the printer tank17W.

A configuration of the number of the tubes8, a branching format and the like are not limited to those of the above-described embodiment. For example, the server tank6W may be connected to the printer tank17W of the single printer1via a plurality of (2, for example) the tubes8that do not branch. In this case, in the supply operation and the return operation, the white ink flows through each of the different tubes8. For example, the tube84need not necessarily be connected to the tube82at the point P2, and may be directly connected to the server tank6W of the printer1A. The tube85need not necessarily be connected to the tube84at the point P4, and may be directly connected to the server tank6W. The server tank6W and the printer tank17W of the single printer1may be connected by the single tube8that does not branch. In this case, in each of the supply operation and the return operation, the white ink flows through the same tube8.

In the above-described embodiment, the liquid supply system100may change each of execution conditions for the supply processing and execution conditions for the circulation processing. For example, the CPU51may execute the supply processing or the circulation processing when the user operates the operation portion186or the operation portion57, and inputs an instruction to execute the supply processing or the circulation processing to the printer1or the liquid supply device2. The CPU51may perform the circulation processing at a time determined in advance.

In the above-described embodiment, the liquid supply system100may omit the server sensor71and the printer sensor185. In this case, the CPU51may store the server remaining amount and the printer remaining amount of an initial state, for example. Furthermore, by performing time control of the pump motors201,211,261, and271using the stored server remaining amount or printer remaining amount as a reference, the CPU51may determine a current server remaining amount or printer remaining amount.

The CPU41may perform the main processing. In this case, the liquid supply system100may omit the CPU51. The CPU51may perform a part of the main processing, and the CPU41may perform another part of the main processing. A CPU of an external device may perform the main processing. The external device is a device other than the printer1and the liquid supply device2, and is a personal computer (PC), a smartphone, or the like.

In place of the CPU41or51, a microcomputer, application specific integrated circuits (ASICs), a field programmable gate array (FPGA) or the like may be used as a processor. The main processing may be performed as distributed processing by a plurality of the processors. It is sufficient that the non-transitory storage media, such as the ROM42or52, the flash memory44or54, and the like be a storage medium capable of storing information, regardless of a period of storing the information. The non-transitory storage medium need not necessarily include a transitory storage medium (a transmitted signal, for example). The control program may be downloaded from a server connected to a network (not shown in the drawings) (in other words, may be transmitted as transmission signals), and may be stored in the ROM42or52or the flash memory44or54. In this case, the control program may be stored in a non-transitory storage medium, such as an HDD provided in the server.