Liquid discharge system and filter state determination method

Abstract

To provide a liquid discharge system in which filters are arranged on a head flow channel and a supply flow channel, respectively, and occurrence of abnormality on either of the filters can be determined.SOLUTION: A liquid discharge system for discharging liquid includes: a first filter positioned in a head flow channel; a second filter positioned in a supply flow channel; a pump for making a liquid in the supply flow channel flow; a first liquid amount sensor for detecting an amount of liquid accumulated in a supply tank; a second liquid amount sensor for detecting an amount of liquid accumulated in a discharge tank; and a controller for determining a state of the first filter on the basis of a first change amount as a change amount of detection values of the first liquid amount sensor in a predetermined period and a second change amount as a change amount of detection values of the second liquid amount sensor in the predetermined period, and determines a state of the second filter on the basis of a value based on the first change amount and the second change amount, and the number of rotations of the pump.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a liquid ejection system and a method for determining a filter state. [Background technology]

[0002] A liquid ejection system is used that ejects a liquid (ink, etc.) from a head having nozzles onto a medium (paper, etc.) to form an image on the medium. In such a liquid ejection system, a filter is disposed in a flow path for supplying the liquid to the nozzles in order to prevent foreign matter, etc., mixed in the liquid from reaching the nozzles.

[0003] As a technique for grasping the state of a filter in a liquid ejection system, Patent Document 1 discloses an inkjet printer equipped with "an estimation unit that estimates the degree of clogging of a filter based on a decrease in the volume of ink droplets." Patent Document 2 discloses a liquid ejection device equipped with "a control unit that determines the degree of clogging of a filter according to the pressure difference between the flow pressure of ink flowing through a first region located on the ink cartridge side of the filter in the ink supply tube and the flow pressure of ink flowing through a second region located on the recording head side of the filter in the ink supply tube." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-112794 A [Patent Document 2] JP 2010-228147 A Summary of the Invention [Problem to be solved by the invention]

[0005] A liquid ejection system is used in which a filter is disposed in each of a head flow path that flows liquid from a supply tank to a discharge tank via a head, and a supply flow path that flows liquid to a supply tank. When trying to determine the state of the filter in such a liquid ejection system, it is difficult to make a good determination even using the estimation unit described in Patent Document 1. This is because it is not possible to determine whether the reduction in the volume of the ink droplets is caused by clogging of a filter disposed in the head flow path or a filter disposed in the supply flow path.

[0006] In addition, it is difficult to make a good judgment even when using the control unit described in Patent Document 2. This is because it is not easy to obtain the ink flow pressures upstream and downstream of the filter arranged in the head flow path by arranging a sensor or the like in the limited space around the head flow path.

[0007] In view of the above, an object of the present invention is to provide a technology that can determine which filter is abnormal in a liquid ejection system in which a filter is arranged in each of a head flow path and a supply flow path. [Means for solving the problem]

[0008] According to a first aspect of the present invention, there is provided a liquid ejection system for ejecting liquid, comprising: a head configured to eject the liquid, the head having a supply port for supplying the liquid to the head and a discharge port for discharging the liquid from the head; A supply tank connected to the supply port; A discharge tank connected to the discharge port; a pump for causing the liquid to flow in a supply flow path that supplies the liquid to the supply tank; a first filter located in a head flow path extending from the supply tank through the head to the discharge tank; A second filter located in the supply flow path; a first liquid amount sensor for detecting the amount of the liquid stored in the supply tank; a second liquid amount sensor for detecting the amount of the liquid stored in the discharge tank; A liquid ejection system is provided which includes a controller that determines a state of the first filter based on a first change amount, which is the amount of change in the detection value of the first liquid volume sensor over a predetermined period of time, or a second change amount, which is the amount of change in the detection value of the second liquid volume sensor over a predetermined period of time, and determines the state of the second filter based on a value based on the first change amount and the second change amount or on the rotation speed of the pump.

[0009] According to a second aspect of the present invention, there is provided a filter state determination method executed by a controller of a liquid ejection system that ejects liquid, the method comprising: The liquid ejection system includes: a head configured to eject the liquid, the head having a supply port for supplying the liquid to the head and a discharge port for discharging the liquid from the head; A supply tank connected to the supply port; A discharge tank connected to the discharge port; a pump for causing the liquid to flow in a supply flow path that supplies the liquid to the supply tank; a first filter located in a head flow path extending from the supply tank through the head to the discharge tank; A second filter located in the supply flow path; a first liquid amount sensor for detecting the amount of the liquid stored in the supply tank; a second liquid amount sensor for detecting the amount of the liquid stored in the discharge tank; determining a state of the first filter based on a first change amount, which is an amount of change in a detection value of the first liquid quantity sensor during a predetermined period, or a second change amount, which is an amount of change in a detection value of the second liquid quantity sensor during a predetermined period; There is provided a filter state determining method including determining a state of the second filter based on a value based on the first amount of change and the second amount of change, or based on a rotation speed of the pump. Effect of the Invention

[0010] According to the liquid ejection system and filter state determination method of the present invention, a user of a liquid ejection system in which filters are arranged in both the head flow path and the supply flow path can determine which filter is abnormal. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a printer according to an embodiment. [Diagram 2] FIG. 2 is a perspective view of the head system. [Diagram 3] FIG. 3 is a side view of the housing of the head system. [Figure 4] FIG. 4 is an exploded perspective view of the subtank. [Diagram 5] FIG. 5 is a bottom view of the subtank. [Figure 6] FIG. 6 is a perspective view of the right end portion of the subtank and the vicinity thereof, and a liquid level detector attached to the subtank. [Figure 7] FIG. 7 is a perspective view of the head mechanism. [Figure 8] FIG. 8 is a plan view of the head. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. [Figure 10] FIG. 10 is a schematic explanatory diagram showing a flow path configuration of an HPM (Hydraulic Pneumatics Module). [Figure 11] FIG. 11 is a flow chart showing a state determination process for determining the state of the head filter. [Figure 12] FIG. 12 is a graph showing the temporal fluctuation of the detection values ​​of the fill tank sensor and the drain tank sensor. [Figure 13] Fig. 13(a) is a graph for explaining the relationship between the change in the amount of ink stored in the fill tank and the slope of the detection value of the fill tank sensor. Fig. 13(b) is a graph for explaining the relationship between the change in the amount of ink stored in the drain tank and the slope of the detection value of the drain tank sensor. [Figure 14]Fig. 14(a) is a graph showing the relationship between the operation time of the head filter and the slope of the detection value of the drain tank sensor, and Fig. 14(b) is an explanatory diagram for explaining an example of a method for calculating the life of the head filter. [Figure 15] FIG. 15 is a flow chart illustrating a state determination process for determining the state of the HPM filter based on the flow rate of the HPM filter. [Figure 16] Fig. 16(a) is a graph showing the relationship between the operating time of the HPM filter and the flow rate of the HPM filter, and Fig. 16(b) is an explanatory diagram for explaining an example of a method for calculating the lifespan of the HPM filter. [Figure 17] FIG. 17 is a flow chart showing a state determination process for determining the state of the HPM filter based on the rotation speed of the pump. [Figure 18] Fig. 18(a) is a graph showing the relationship between the operating time of the HPM filter and the rotation speed of the pump, and Fig. 18(b) is an explanatory diagram for explaining another example of a method for calculating the life of the HPM filter. [Figure 19] FIG. 19 is a flow chart showing a modified example of the state determination process for determining the state of the head filter. [Figure 20] FIG. 20 is a flow chart illustrating a modified state determination process for determining the state of the HPM filter based on the flow rate of the HPM filter. [Figure 21] FIG. 21 is a flow chart showing a modified state determination process for determining the state of the HPM filter based on the rotational speed of the pump. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] [Embodiment] A printer 1000 (an example of a "liquid ejection system") according to an embodiment will be described with reference to FIGS.

[0013] <Printer 1000> 1, the printer 1000 mainly includes four head systems 100, a platen 200, transport rollers 301 and 302, an ink tank 400, a hydraulic pneumatics module (HPM) 500, an air pressure regulator 600, a controller 700, and a housing 800 that houses these components. The printer 1000 further includes a display unit 900 located on the outer surface of the housing 800.

[0014] In the printer 1000, the direction in which the transport rollers 301 and 302 are aligned, i.e., the direction in which the medium PM is transported during image formation, is referred to as the “transport direction.” Additionally, the direction that extends in the horizontal plane and is perpendicular to the transport direction is referred to as the “medium width direction.”

[0015] Each of the four head systems 100 is a so-called line-type head (head bar), and is supported by a frame 100a at both ends in the medium width direction. The specific structure and function of the head system 100 will be described later.

[0016] The frame 100a supports the four head systems 100 such that the front-rear direction (described later) of each of the four head systems 100 coincides with the transport direction of the printer 1000 and the nozzle surfaces 40n (described later) of the four head systems 100 face the upper surface of a platen 200.

[0017] The platen 200 is a plate-like member that supports the medium PM from the side opposite the head system 100 (below) when ink (an example of a "liquid") is ejected from the head system 100 toward the medium PM.

[0018] The transport rollers 301 and 302 are disposed on either side of the platen 200 in the transport direction. The transport rollers 301 and 302 function as a transport device that sends the medium PM in a predetermined manner in the transport direction when the head system 100 forms an image on the medium PM.

[0019] The ink tank 400 (an example of a "storage tank") is divided into four main tanks 410 to accommodate four colors of ink. Each of the four main tanks 410 is connected to one of the four head systems 100 by the HPM 500.

[0020] A total of four HPMs 500 are provided, one for connecting one main tank 410 and one head system 100. The specific structure and function of the HPM 500 will be described later.

[0021] In this embodiment, four different types of ink are stored in each of the four main tanks 410, and each of the four head systems 100 ejects one of the four different types of ink. As an example, the four types of ink are cyan ink, magenta ink, yellow ink, and black ink.

[0022] The air pressure regulator 600 is a mechanism, such as a pump, that adjusts the pressure inside the sub-tank 20 (described later) of the head system 100. A total of four air pressure regulators 600 are provided, one for each head system 100 (only one is shown representatively in FIG. 1).

[0023] The controller 700 controls each part of the printer 1000 as a whole, causing each part to perform operations such as forming an image on the medium PM. The controller 700 includes an FPGA (Field Programmable Gate Array), an EEPROM (Electrically Eracable Programmable Read-Only Memory), and a RAM (Random Access Memory). The controller 700 may also include a CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit). The controller 700 is connected to an external device (not shown) such as a PC so as to be able to communicate data with the printer 1000, and controls each part of the printer 1000 based on print data sent from the external device.

[0024] The display unit 900 is a device for visually presenting information to a user. Specifically, the display unit 900 is, for example, a liquid crystal monitor.

[0025] <Head System 100> 2, each of the four head systems 100 mainly comprises a housing 10, a subtank 20, a liquid level detection unit 30, ten head mechanisms 40 arranged in a staggered pattern, a relay board 50, and a control board unit 60. Since the four head systems 100 have the same configuration, the following description focuses on one of the four.

[0026] In the following description, the direction in which the ten head mechanisms 40 are arranged in a staggered (zigzag) pattern is referred to as the width direction of the head system 100, and the direction in which the ten head mechanisms 40 and the subtanks 20 are arranged is referred to as the up-down direction. In addition, the direction perpendicular to the width direction and up-down direction is referred to as the front-rear direction of the head system 100.

[0027] 2 are defined as the front and rear sides in the front-to-rear direction. Regarding the width direction, the left and right sides when viewed from the front in the front-to-rear direction are defined as the left and right sides in the width direction. Regarding the up-down direction, the side where the sub-tanks 20 are located with respect to the ten head mechanisms 40 is defined as the upper side, and the opposite side is defined as the lower side.

[0028] When the head system 100 is mounted on the printer 1000 , the width direction of the head system 100 coincides with the medium width direction of the printer 1000 , and the front-rear direction of the head system 100 coincides with the transport direction of the printer 1000 .

[0029] <Case 10> The housing 10 may be made of, for example, metal. The housing 10 includes a first housing 11 and a second housing 12 that is detachable from the first housing 11.

[0030] The first housing 11 has a top plate 11a, a bottom plate 11b, a front wall (not shown in FIG. 2 in order to show the interior of the first housing 11), a rear wall 11d, a left wall 11e, and a right wall 11f. Inside the first housing 11, a space S1 is defined that is surrounded by the top plate 11a, the bottom plate 11b, the front wall, the rear wall 11d, the left wall 11e, and the right wall 11f.

[0031] The top plate 11a has a first region 11a1, a second region 11a2 located to the right of the first region 11a1, and a vertical region 11a3 between the first region 11a1 and the second region 11a2. The first region 11a1 is located above the second region 11a2.

[0032] As shown in FIG. 3, a power connector CN is provided on the upper portion of the left wall 11e, and below the power connector CN, two air vents AP 10 Two air vents AP 10 Below the ink supply, there are two ink flow ports arranged in the front-to-back direction. 10 It is equipped with a power connector CN and two air vents AP 10 and two ink flow ports IP 10 is omitted in FIG. 2.

[0033] 2, the second housing 12 has a top plate 12a, a bottom plate 12b, a front wall 12c, a rear wall 12d, a left wall 12e, and a right wall 12f. When the second housing 12 is attached to the first housing 11, the bottom plate 12b of the second housing 12 abuts against the second region 11a2 of the top plate 11a of the first housing 11.

[0034] <Subtank 20> The subtank 20 receives and stores the ink supplied to the head system 100. The ink stored in the subtank 20 is distributed to each of the multiple head mechanisms 40.

[0035] As shown in FIG. 2, the sub-tank 20 has an elongated shape, and is disposed in the space S1 so that the longitudinal direction coincides with the width direction of the head system 100.

[0036] 4 and 5, the subtank 20 is composed of a main body 21, a top plate 22, and a bottom plate 23. A heater 24 (FIG. 5) is attached to the lower surface of the bottom plate 23.

[0037] The main body 21 is formed of resin, for example. The main body 21 has a front wall 21c and a rear wall 21d extending along a plane perpendicular to the front-rear direction of the head system 100, and a left wall 21e and a right wall 21f extending along a plane perpendicular to the width direction of the head system 100. Inside the main body 21, there is a separation wall 21w parallel to the front wall 21c and the rear wall 21d.

[0038] The top plate 22 is, for example, a flat plate made of metal. The shape of the top plate 22 in a plan view is the same as the outline shape of the main body 21 when viewed from above. The top plate 22 is fixed to the upper end of the main body 21 with a seal rubber (not shown) sandwiched therebetween.

[0039] The bottom plate 23 is a flat plate made of metal. The shape of the bottom plate 23 in a plan view is the same as the outline shape of the main body 21 when viewed from above. The bottom plate 23 is fixed to the lower end of the main body 21 with a seal rubber (not shown) sandwiched therebetween.

[0040] 4, in the subtank 20, a fill tank FT (an example of a "supply tank") is formed by the front wall 21c, the partition wall 21w, the left wall 21e, and the right wall 21f of the main body 21, the top plate 22, and the bottom plate 23. A drain tank DT (an example of a "discharge tank") is formed by the rear wall 21d, the partition wall 21w, the left wall 21e, and the right wall 21f of the main body 21, the top plate 22, and the bottom plate 23. The internal space IN of the fill tank FT FT and the internal space of the drain tank DT IN DT are closed spaces and are separated from each other.

[0041] The left wall 21e has two ink flow ports IP 20 are arranged in the front-rear direction. 20 The internal space of the fill tank FT IN FTThe ink flow port IP at the rear 20 is the internal space of the drain tank DT DT It is connected to.

[0042] The top plate 22 has two air vents AP 20 The front air vents AP are aligned in the front-rear direction. 20 The internal space of the fill tank FT IN FT The rear air vent AP 20 is the internal space of the drain tank DT DT As shown in FIG. 10, the two air vents AP 20 are connected to the air vent AP at the rear of the housing 10 through a duct AT. 10 1. The air pressure regulator 600 is connected to the air pressure regulator 600 via

[0043] Ten ink circulation port sets S are provided on the lower surface of the bottom plate 23 (FIG. 5). Each of the ink circulation port sets S includes one ink supply port SP and one ink discharge port DP. The ten ink circulation port sets S are arranged in a staggered (zigzag) pattern along the width direction of the head system 100. In each ink circulation port set S, the ink supply port SP and the ink discharge port DP are aligned in the width direction.

[0044] A flow path (not shown) formed in the lower part of the inside of the main body 21 allows the internal space IN of the fill tank FT to flow through the FT are connected to the ink supply ports SP of each ink circulation port set S, and the internal space IN of the drain tank DT DT are connected to the ink discharge ports DP of each ink flow port set S.

[0045] <Liquid level detection unit 30> As shown in FIG. 6, the liquid level detection unit 30 includes a fill tank sensor 31 (an example of a "first liquid level sensor") that detects the position of the liquid level of the ink stored in the fill tank FT, and a drain tank sensor 32 (an example of a "second liquid level sensor") that detects the position of the liquid level of the ink stored in the drain tank DT.

[0046] The fill tank sensor 31 and the drain tank sensor 32 are both known capacitance type liquid level sensors. The fill tank sensor 31 mainly has a flat detection electrode 31E attached to the front wall 21c near the right end of the subtank 20. The drain tank sensor 32 mainly has a flat detection electrode 32E attached to the rear wall 21d near the right end of the subtank 20.

[0047] The fill tank sensor 31 forms a pseudo capacitor with the detection electrode 31E and a grounded metal surface in the vicinity thereof. The grounded metal surface may be, for example, a metal plate built into the fill tank sensor 31, or may be the top plate 22, bottom plate 23, etc. of the subtank 20. Similarly, the drain tank sensor 32 forms a pseudo capacitor with the detection electrode 32E and a grounded metal surface in the vicinity thereof. The grounded metal surface may be, for example, a metal plate built into the drain tank sensor 32, or may be the top plate 22, bottom plate 23, etc. of the subtank 20.

[0048] In the fill tank sensor 31 and the drain tank sensor 32, the capacitance value of the pseudo capacitor is FT Position of the liquid surface in the internal space IN DT The capacitance value of the fill tank sensor 31 and the capacitance value of the drain tank sensor 32 each output a capacitance value of a pseudo capacitor to the controller 700.

[0049] <Head mechanism 40> 7, each of the ten head mechanisms 40, which have the same configuration, includes, in order from the top, a connection plate 41, a main body 42, and a head 43. The head mechanism 40 further includes a wiring connection part WC that extends in the vertical direction between the upper part of the connection plate 41 and the head 43.

[0050] The connection plate 41 is provided with an ink supply pipe connection portion ISC and an ink discharge pipe connection portion IDC.

[0051] The main body 42 is fixed to the lower surface of the connection plate 41. The main body 42 has therein a flow path that supplies ink supplied to the ink supply pipe connection portion ISC to the head 43, and a flow path that returns ink not ejected from the head 43 to the ink discharge pipe connection portion IDS.

[0052] The head 43 is fixed to the lower surface of the main body 42. As shown in Figures 8 and 9, the head 43 includes a flow path unit 431 and a piezoelectric actuator 432.

[0053] 9, the flow path unit 431 is a laminated structure in which an ink sealing film 431A, plates 431B to 431E, and a nozzle plate 431F are laminated in this order from above. As shown in FIG. 8, a flow path CH is formed inside the flow path unit 431.

[0054] The flow channel CH has eight ink flow ports IP 43 Each of the four manifold channels M1 to M4 is a linear channel, and has an ink flow port IP 43 Each of the four manifold channels M1 to M4 is connected to 12 individual channels iCH.

[0055] 8 ink flow ports IP 43 Each of the head filters F HD (an example of a "first filter") is located in the head filter F. HD is configured to remove foreign matter and air bubbles that have become mixed into the ink.

[0056] As shown in FIG. 9, each of the individual channels iCH includes a pressure chamber 1, a descender channel 2, and a nozzle 3. The upper surface of the pressure chamber 1 is formed by an ink sealing film 431A. The descender channel 2 extends in the vertical direction from the pressure chamber 1 toward the nozzle 3. The nozzle 3 is a minute opening that ejects ink toward the medium PM, and is formed in the nozzle plate 431F. The lower surface of the nozzle plate 431F is the lower surface of the head mechanism 40, and is the nozzle surface 40n. On the nozzle surface 40n, a nozzle row L is formed along the direction in which the manifold channels M1 to M4 extend. 3 (Figure 8) is formed.

[0057] 9, the piezoelectric actuator 432 is composed of a first piezoelectric layer L1 provided on the upper surface of the flow path unit 431, a second piezoelectric layer L2 above the first piezoelectric layer L1, a common electrode cET sandwiched between the first piezoelectric layer L1 and the second piezoelectric layer L2, and a plurality of individual electrodes iET provided on the upper surface of the second piezoelectric layer L2. The plurality of individual electrodes iET are provided on the upper surface of the second piezoelectric layer L2 so as to be located above the pressure chambers 1 of the plurality of individual flow paths iCH. The portions of the second piezoelectric layer L2 sandwiched between the common electrode cET and each of the plurality of individual electrodes iET become active portions AC polarized in the thickness direction.

[0058] Each of the individual electrodes iET of the piezoelectric actuator 432 is connected to a control board 442 on which a driver IC is mounted via an FPC (Flexible Printed Circuits) 441. The control board 442 is disposed inside the main body 42.

[0059] The wiring connection part WC is in the form of a substrate. An upper end of the wiring connection part WC protrudes above the connection plate 41. The wiring connection part WC is connected to a relay board 50 (described later) via a flexible substrate (not shown). A lower end of the wiring connection part WC is connected to a control substrate 442.

[0060] Each of the head mechanisms 40 is fixed to the bottom 11b of the first housing 11 (FIG. 2). In this state, the nozzle surface 40n of each head mechanism 40 is exposed toward the bottom of the housing 10. In addition, the nozzle row L of the nozzle surface 40n 3 extends along the width direction of the head system 100. The ten head mechanisms 40 are arranged in a staggered (zigzag) pattern along the width direction.

[0061] Each of the head mechanisms 40 and the sub-tank 20 are connected by an ink tube set ITS (FIG. 2). The ink tube set ITS includes one ink supply tube IST and one ink discharge tube IDT.

[0062] The upper end of each ink supply tube IST is connected to the ink supply port SP of each ink circulation port set S of the subtank 20. The lower end of each ink supply tube IST is connected to the ink supply tube connection part ISC of the head mechanism 40. The upper end of each ink discharge tube IDT is connected to the ink discharge port DP of each ink circulation port set S of the subtank 20. The lower end of each ink discharge tube IDT is connected to the ink discharge tube connection part IDC of the head mechanism 40.

[0063] The ink supplied from the sub tank 20 to the ink supply pipe connection portion ISC through the ink supply pipe IST is branched in the main body portion 42 and flows through the ink flow port IP 43 flows into

[0064] The flow paths of the main body 42 are configured so that ink supplied to the ink supply pipe connection portion ISC flows through the manifolds M1-M4, and ink discharged from the manifolds M1-M4 flows to the ink discharge pipe connection portion IDC. The flow paths may be configured so that ink flows in the same direction in all of the manifolds M1-M4, or the flow directions of ink in the manifolds M1 and M3 are opposite to each other.

[0065] <Relay board 50> The relay board 50 mainly serves as a relay between a control board unit 60 (described later) and a control board 442 of the head mechanism 40. The relay board 50 is connected to the wiring connection parts WC of each of the ten head mechanisms 40 by a flexible board (not shown).

[0066] The relay board 50 is also connected to an electric connector CN of the housing 10 by wiring (not shown), and distributes the power supplied from the electric connector CN to the control board unit 60 and the like.

[0067] 2, the relay board 50 is attached to the lower surface of the second region 11a2 of the top plate 11a in parallel to the second region 11a2. That is, the mounting surface of the relay board 50 is parallel to the upper and lower surfaces of the second region 11a2 and is parallel to a plane including the width direction and the front-rear direction.

[0068] <Control board unit 60> The control board unit 60 receives print data signals from the controller 700 of the printer 1000, and sends them to the control board 442 of each head mechanism 40 via the relay board 50. The control board unit 60 is provided inside the second housing 12 of the housing 10 (FIG. 2).

[0069] A terminal (not shown) of the control board unit 60 protrudes downward through an opening (not shown) provided in the bottom plate 12b of the second housing 12. The second housing 12 is attached to and detached from the first housing 11 by attaching and detaching the terminal to and from a connector (not shown) of the relay board 50 through an opening (not shown) provided in the second area 11a2 of the top plate 11a of the first housing 11.

[0070] <hpm500> 1, each of the four HPMs 500 (short for Hydraulic Pneumatics Module) connects one of the four main tanks 410 of the ink tank 400 to one of the four head systems 100. Since the four HPMs 500 have the same configuration, the following description focuses on one of the four.

[0071] As shown in FIG. 10, the HPM 500 includes a pump P, a degassing unit DU, five flow paths (flow paths CH1 to CH5), five valves (valves V1 to V5), and an HPM filter F. HPM (an example of a "second filter").

[0072] The flow channel CH1 connects the main tank 410 and the suction port PA of the pump P. The flow channel CH2 connects the main tank 410 and the suction port IP 10 and the ink flow port IP on the front side of the subtank 20 20 The flow channel CH3 connects the discharge port PB of the pump P to the fill tank FT via the ink supply port IP 10 and the ink flow port IP on the rear side of the subtank 20 20 The flow path CH2 and the drain tank DT are connected via the flow path CH4. The flow path CH1 and the flow path CH3 are connected via the flow path CH5. The flow path CH2 and the main tank 410 are connected via the flow path CH5.

[0073] The flow channel CH3 is connected to the flow channel CH2 at a branch J1 of the flow channel CH2. The flow channel CH4 is connected to the flow channel CH1 at a branch J2 of the flow channel CH1 and is connected to the flow channel CH3 at a branch J3 of the flow channel CH3. The flow channel CH5 is connected to the flow channel CH2 at a branch J4 of the flow channel CH2.

[0074] Valve V1 is located in flow path CH1, between main tank 410 and branch J2. Valve V2 is located in flow path CH2, between branch J1 and fill tank FT. Valve V3 is located in flow path CH3, between branch J1 and branch J3. Valve V4 is located in flow path CH4. Valve V5 is located in flow path CH5. Valves V1 to V5 open and close flow paths CH1 to CH5, respectively.

[0075] The degassing unit DU is located in the flow path CH2 between the pump P and the branch J4. In this embodiment, the degassing unit DU is a known degassing module, and removes gases such as air contained in the ink passing through the degassing unit DU.

[0076] HPM Filter F HPM is located in the flow path CH2 between the pump P and the degassing unit DU.

[0077] In the following description, the flow path from the main tank 410 through flow path CH1 and flow path CH2 to the fill tank FT is called a supply flow path SCH. The flow path from the drain tank DT through flow path CH3, branch J3, flow path CH4, branch J2, flow path CH1, flow path CH2, branch J4, and flow path CH5 to the main tank 410 is called a discharge flow path DCH. Also, the flow path from the fill tank FT through the ink supply pipe IST, the flow path CH of the head 43, and the ink discharge pipe IDT to the drain tank DT is called a head flow path HCH. The supply flow path SCH and the discharge flow path DCH include an HPM filter F. HPM The head flow channel HCH is equipped with a head filter F HD is located.

[0078] <Printing method> The printer 1000 forms an image on the medium PM as follows, with the controller 700 controlling each section of the printer 1000.

[0079] The controller 700 controls the HPM 500 and the air pressure regulator 600 to send ink from the main tank 410 to the head system 100. As an example, the controller 700 sends ink from the main tank 410 to the fill tank FT via the supply flow path SCH by driving the pump P while opening the first valve V1 and the second valve V2 of the HPM 500 and closing the third valve V3 to the fifth valve V5.

[0080] The air pressure regulator 600 is connected to the internal space IN of the fill tank FT. FT The air pressure in the air layer (the area where air exists above the ink surface) is DT The air pressure in the fill tank FT is adjusted so that it is higher than the air pressure in the air layer in the head 43. This causes the ink in the fill tank FT to be sent to the head flow path HCH. The ink sent from the fill tank FT to the head flow path HCH is sent to the flow path CH of the head 43 via the ink supply pipe IST. In the head 43, the ink that is not ejected from the nozzles 3 is sent to the drain tank DT via the ink discharge pipe IDT.

[0081] When discharging ink from the drain tank DT, the controller 700, for example, drives the pump P while opening the fourth valve V4 and the fifth valve V5 and closing the first valve V1 to the third valve V3. This causes the ink in the drain tank DT to return to the main tank 410 via the discharge flow path DCH.

[0082] In parallel with the above-mentioned ink supply, the controller 700 sends print data corresponding to the image to be formed to the control board unit 60. The control board unit 60 sends the print data to the control board 442 of each head mechanism 40 via the relay board 50 and a flexible board (not shown). The control board 442 of each head mechanism 40 drives each of the multiple piezoelectric actuators 432 at appropriate timing based on the print data, and ejects ink from the nozzles 3 at appropriate timing.

[0083] The controller 700 alternately ejects ink and transports the medium PM using the transport rollers 301, 302, thereby forming an image on the medium PM according to the print data.

[0084] <Filter status determination> The filter state determination executed by the printer 1000 of this embodiment will be described. The filter state determination is executed by the head filter F HD and HPM filter F HPM The head filter F HD State judgment and HPM filter F HPM The state determinations may be performed at the same timing or at different timings.

[0085] (1) Head filter F HD Status judgment The head filter F implemented by the printer 1000 of this embodiment HD In this embodiment, the controller 700 executes a state determination process P100 (FIG. 11) to determine the state of the head filter F. HD The controller 700 judges the status of the device and presents information corresponding to the judgment result to the user. The controller 700 executes the status judgment process P100 periodically (for example, once a day).

[0086] In the state determination process P100, the controller 700 uses the slope (gradient) X of the detection value (capacitance value) of the fill tank sensor 31 or the slope (gradient) Y of the detection value (capacitance value) of the drain tank sensor 32 as a value indicating the flow rate of ink flowing through the head flow path HCH. The slope X of the detection value of the fill tank sensor 31 is the amount of change in the detection value of the fill tank sensor (first liquid level sensor) 31 during a predetermined period, and is an example of the "first amount of change." The slope Y of the detection value of the drain tank sensor 32 is the amount of change in the detection value of the drain tank sensor (second liquid level sensor) 32 during a predetermined period, and is an example of the "second amount of change." The length of the predetermined period can be set arbitrarily. The reason why the slope X of the detection value of the fill tank sensor 31 or the slope Y of the detection value of the drain tank sensor 32 can be used as a value indicating the flow rate of ink flowing through the head flow path HCH is as follows.

[0087] 12, the solid line graph shows the time variation of the detection value (capacitance value) of the fill tank sensor 31, and the dashed line graph shows the time variation of the detection value (capacitance value) of the drain tank sensor 32. The vertical axis of FIG. 12 is the detection value (capacitance value), and the horizontal axis is time.

[0088] Since the dielectric constant of ink is generally higher than that of air, when the amount of ink stored in the fill tank FT increases (i.e., when the liquid level rises), the capacitance value of the pseudo capacitor constituted by the fill tank sensor 31 (i.e., the detection value of the fill tank sensor 31) increases. Conversely, when the amount of ink stored in the fill tank FT decreases (i.e., when the liquid level drops), the capacitance value of the pseudo capacitor constituted by the fill tank sensor 31 (i.e., the detection value of the fill tank sensor 31) decreases. The same is true for the detection value of the drain tank sensor 32.

[0089] Therefore, as shown in FIG. 13(a), if the amount of ink stored in the fill tank FT increases greatly during period PP (one example of a "predetermined period" which can be of any length), the increase in the detection value of the fill tank sensor 31 also increases, and as a result the slope X of the detection value of the fill tank sensor 31 increases. If the increase in the amount of ink stored in the fill tank FT during period PP is small, the slope X also decreases, and if the increase in the amount of ink stored in the fill tank FT during period PP is zero, the slope X also becomes zero. Also, if the amount of ink stored in the fill tank FT decreases during period PP, the slope X becomes a negative value.

[0090] The same relationship applies to the drain tank sensor 32. As shown in Fig. 13(b), if the amount of ink stored in the drain tank DT increases greatly during the period PP, the amount of increase in the detection value of the drain tank sensor 32 also increases, and as a result, the slope Y of the detection value of the drain tank sensor 32 increases. If the amount of ink stored in the drain tank DT increases small during the period PP, the slope Y also decreases, and if the increase in the amount of ink stored in the drain tank DT during the period PP is zero, the slope Y also becomes zero. Also, if the amount of ink stored in the drain tank DT decreases during the period PP, the slope Y becomes a negative value.

[0091] Here, consider the magnitude of the slope X when ink is supplied from the fill tank FT to the drain tank DT via the head flow path HCH with the supply of ink to the fill tank FT and the ejection of ink from the head 43 stopped. In this case, the slope X has a magnitude that corresponds to the outflow amount from the fill tank FT, i.e., the flow rate of ink flowing through the head flow path HCH. Similarly, consider the magnitude of the slope Y when ink is supplied from the fill tank FT to the drain tank DT via the head flow path HCH with the discharge of ink from the drain tank DT and the ejection of ink from the head 43 stopped. In this case, the slope Y has a magnitude that corresponds to the inflow amount of ink to the drain tank DT, i.e., the flow rate of ink flowing through the head flow path HCH.

[0092] In this way, the magnitude of the slopes X and Y in a given state corresponds to the flow rate of ink flowing through the head flow channel HCH. Therefore, the controller 700 can use the slope X of the detection value of the fill tank sensor 31 or the slope Y of the detection value of the drain tank sensor 32 as a value indicating the flow rate of ink flowing through the head flow channel HCH.

[0093] The state determination process P100 will be described below using as an example a case where the slope Y of the detection value of the drain tank sensor 32 is used as a value indicating the flow rate of ink flowing through the head flow path HCH. The state determination process P100 can be performed in the same manner as described below even when the slope X of the detection value of the fill tank sensor 31 is used as a value indicating the flow rate of ink flowing through the head flow path HCH. Note that, in order to provide redundancy, the state determination process P100 using the slope X of the detection value of the fill tank sensor 31 and the state determination process P100 using the slope Y of the detection value of the drain tank sensor 32 may be executed in parallel or one after the other. In this case, one determination result can be used as a backup when a problem such as an error or an abnormal value occurs in the other determination result.

[0094] In step S101 of the state determination process P100 (FIG. 11), the controller 700 determines whether the pressure difference PD between the fill tank FT and the drain tank DT is being appropriately controlled.

[0095] The controller 700 determines whether the differential pressure PD is being appropriately controlled in the following procedure.

[0096] First, the controller 700 controls the HPM 500 and the air pressure regulator 600 to send ink from the main tank 410 to the drain tank DT via the supply flow path SCH and the head flow path HCH. In this state, the controller 700 obtains the slope Y of the detection value of the drain tank sensor 32. Next, the controller 700 stops the supply of ink from the supply flow path SCH to the fill tank FT, and controls the air pressure regulator 600 to send ink from the fill tank FT to the drain tank DT via the head flow path HCH. In this state, the controller 700 obtains the slope Y of the detection value of the drain tank sensor 32. After that, the controller 700 compares the slope Y obtained while sending ink from the main tank 410 to the drain tank DT with the slope Y obtained while sending ink from the fill tank FT to the drain tank DT, and if the two values ​​are equal, it is determined that the differential pressure PD is appropriately controlled. This is because if the amount of ink sent to the drain tank DT is the same regardless of whether or not ink is being supplied to the fill tank FT (in other words, whether or not the liquid level in the fill tank FT changes), it is considered that the differential pressure PD is being appropriately controlled.On the other hand, if the two values ​​are different, it is determined that the differential pressure PD is not being appropriately controlled.

[0097] The controller 700 may determine whether the differential pressure PD is appropriately controlled based on a comparison between the gradient X obtained while the ink in the fill tank FT is being sent to the drain tank DT and the gradient X obtained while the ink in the fill tank FT is being sent to the main tank 410 via the head flow path HCH and the discharge flow path DCH. In this case, too, if the two values ​​are equal, it is determined that the differential pressure PD is appropriately controlled.

[0098] If the controller 700 determines that the differential pressure PD is not appropriately controlled (step S101: NO), it displays information indicating that an abnormality has occurred in the control of the differential pressure PD on the display unit 900 (step S107), and terminates the state determination process P100.

[0099] When it is determined that the pressure difference PD is appropriately controlled (step S101: YES), the controller 700 determines in step S102 whether the amount of decrease in the slope Y of the detection value of the drain tank sensor 32 from the time of the previous execution of the state determination process P100 is equal to or greater than the decrease amount threshold TH ΔY It is determined whether the amount of decrease in the slope is smaller than the decrease threshold TH ΔY The fact that the slope Y of the detection value of the drain tank sensor 32 is smaller than the slope Y of the detection value of the drain tank sensor 32 indicates that the slope Y of the detection value of the drain tank sensor 32 has not decreased significantly compared to the previous execution of the state determination process P100. Note that such a large decrease in the slope Y of the detection value of the drain tank sensor 32 in a short period of time may indicate that a relatively large foreign object has been deposited on the head filter F. HD This can occur when a

[0100] First, the controller 700 sets the slope Y of the detection value of the drain tank sensor 32 obtained during the previous execution of the status determination process P100 as slope Y0, and the slope Y of the detection value of the drain tank sensor 32 newly obtained in the current status determination process as slope Y1, and calculates the slope reduction amount ΔY using equation (1) (note that the slopes Y0 and Y1 are values ​​obtained under conditions where they correspond to the flow rate of the head flow path HCH). ΔY=Y0-Y1 … Equation (1)

[0101] Thereafter, the controller 700 calculates the calculated inclination decrease amount ΔY by a decrease amount threshold TH ΔY The controller 700 compares the slope decrease amount ΔY with the decrease amount threshold TH ΔY If the number is equal to or greater than the number of the first filter (S102: NO), the process proceeds to step S108, and a head maintenance alert (an example of a "notification regarding the first filter") is issued. Specifically, the controller 700 performs maintenance of the head 43 (specifically, for example, the head filter F HD The display unit 900 displays information indicating that a head maintenance alert (replacement of the ink cartridge 41, replacement of the head 43, etc.) is necessary. Note that the head maintenance alert issued by the controller 700 in step S108 is based on a sudden decrease in the slope Y (i.e., the flow rate of ink flowing through the head flow channel HCH) and is considered to be of high urgency. Therefore, the controller 700 may display information urging the user to perform immediate replacement. After that, the controller 700 ends the status determination process P100.

[0102] The controller 700 determines whether the inclination decrease amount ΔY is equal to or smaller than the decrease amount threshold TH ΔY If it is smaller (S102: YES), the process proceeds to step S103. In step S103, the controller 700 determines the head filter F based on the slope Y of the detection value of the drain tank sensor 32. HD Calculate the lifespan (remaining lifespan, remaining usable period).

[0103] In this embodiment, the controller 700 controls the head filter F in the following manner. HD Calculate the life span.

[0104] As shown in FIG. 14A, the slope Y of the detection value of the drain tank sensor 32 (a value acquired under a condition in which the value corresponds to the flow rate of the head flow channel HCH) is proportional to the operating time of the printer 1000 (and thus the head filter F HD This is because the head filter F HD Deterioration or accumulation of minute clogs occurs with use, and the head filter F HD This is because the amount of ink flowing through the head flow channel HCH is reduced. Y When the temperature drops to , the head filter F HD can be considered to be in a state where it is no longer suitable for use.

[0105] Here, the current operating time is the operating time OH1, and the slope Y of the detection part of the drain tank sensor 32 is the threshold value TH Y If the operating time at the time when the head filter F drops to is operating time OH2, the period from operating time OH1 to operating time OH2 is HD Lifespan LT HD is equivalent to.

[0106] In view of the above, the controller 700 calculates the time series data SD of the gradient Y (a value acquired under a condition in which the value corresponds to the flow rate of the head flow channel HCH) accumulated in the state determination process P100 executed so far. Y Based on the head filter F HD Lifespan LT HD The controller 700 calculates, for example, the time series data S. Y The life LT can be calculated by calculating the slope of the time-dependent change in slope Y based on HD Specifically, for example, as shown in FIG. 14B, the controller 700 obtains a straight line passing through the time series data SD of the slope Y by a linear approximation method such as the least squares method, and calculates whether the value of the slope Y indicated by the straight line is equal to or exceeds the threshold value TH Y Then, find the point A1 that matches the head filter F HD Lifespan LT HD is calculated as the difference between the operating time OH2 indicated by point A1 and the current operating time OH1.

[0107] In step S103, the controller 700 HD Filter life LT HD After calculating, in step S104, the filter life LT HD is the first threshold TH1 HD (An example of a "first filter threshold") Determine whether the first threshold TH1 is equal to or smaller than the first threshold TH1 HD For example, it may be several months to several years.

[0108] The controller 700 determines the filter life LT HD is the first threshold TH1 HD If it is greater than (S104: NO), the head filter F HD The display unit 900 displays information indicating that the head filter F is in a normal state (S109), and the state determination process P100 is terminated. HD The information indicating that the condition of the filter is normal may be, for example, text information or an icon indicating that the condition is "normal." HD is the first threshold TH1 HD The indication that the head filter is larger than F HD 13 is an example of a display of information indicating that the status is normal.

[0109] The controller 700 determines the filter life LT HD is the first threshold TH1 HD If it is equal to or less than the filter life LT (S104: YES), in step S105, HD is the second threshold TH2 HD (An example of a "first filter notification threshold value") HD is the first threshold TH1 HD The value is smaller than the above, and may be, for example, on the order of several days to several weeks.

[0110] The controller 700 determines the filter life LT HD is the second threshold TH2 HD If it is equal to or greater than the filter life LT calculated in step S103, HD is displayed on the display unit 900 (S110), and the state determination process P100 is terminated. HD may be displayed as the life of the head 42. The controller 700 may display the filter life LT HD is the second threshold TH2 HD If it is smaller (S105: YES), the process proceeds to step S106, and a head maintenance alert (an example of a "notification regarding the first filter") is issued. Specifically, the controller 700 performs maintenance of the head 43 (specifically, for example, the head filter F HD The display unit 900 displays information indicating that a head maintenance alert (replacement of the head 41, replacement of the head 42, etc.) is necessary. Note that the head maintenance alert issued by the controller 700 in step S106 is based on a gradual decrease in the slope Y (i.e., the flow rate of ink flowing through the head flow channel HCH) that is assumed in advance, and is considered to be less urgent than the head maintenance alert issued in step S108. For this reason, the controller 700 may display in a manner different from that in step S108, and may, for example, display information urging the user to replace the head 41 in the near future. Thereafter, the controller 700 ends the state determination process P100.

[0111] (2) HPM Filter F HPM Status judgment The HPM filter F executed by the printer 1000 of this embodiment HPM The printer 1000 of this embodiment determines the state of the HPM filter F. HPM HPM filter F based on flow rate Q HPM The HPM filter F based on the state judgment of the pump P and the rotation speed HPM and performing at least one of the above state determinations.

[0112] (2-1)HPM Filter F HPM State judgment based on flow rate Q First, the HPM filter F HPM HPM filter F based on flow rate Q HPM The printer 1000 does not have a feedback control of the rotation speed of the pump P, and the HPM filter F HPM In the embodiment in which the rotation speed of the pump P is constant regardless of the state of the HPM filter F HPM HPM filter F based on flow rate Q HPM In this embodiment, the controller 700 executes a state determination process P200 shown in the flowchart of FIG. 15 to determine the state of the HPM filter F HPM The controller 700 performs a state determination process P200 periodically (for example, once a day).

[0113] In step S201, the controller 700 controls the HPM filter F HPM Specifically, the controller 700 estimates the flow rate Q by, for example, the following method.

[0114] First, the controller 700 controls the HPM 500 and the air pressure regulator 600 to send ink from the main tank 410 to the drain tank DT via the supply flow path SCH and the head flow path HCH. At this time, the controller 700 does not discharge ink from the drain tank DT to the discharge flow path DCH. In this state, the controller 700 obtains the slope X of the detection value of the fill tank sensor 31 and the slope Y of the detection value of the drain tank sensor 32.

[0115] As shown in FIG. 10, the flow rate of ink flowing from the supply flow channel SCH to the fill tank FT during a predetermined period is defined as an inflow amount QF IN The flow rate of ink flowing from the fill tank FT to the head flow channel HCH during a given period is the outflow amount QF OUT Then, the amount of change ΔQF in the amount of ink stored in the fill tank FT during a predetermined period is expressed by equation (2). ΔQF=QF IN -QF OUT … Formula (2)

[0116] The flow rate of ink flowing from the head flow channel HCH to the drain tank DT during a given period is defined as the inflow amount QD IN The flow rate of ink flowing from the drain tank DT to the discharge flow path DCH during a given period is called the outflow amount QD OUT Then, the amount of change ΔQD in the amount of ink stored in the drain tank DT during a predetermined period is expressed by equation (3). ΔQD=QD IN -QD OUT … Formula (3)

[0117] Here, when the ink in the main tank 410 is sent to the drain tank DT via the supply flow channel SCH and the head flow channel HCH, the liquid is not ejected from the head 42, so the outflow amount QF OUT and inflow QD IN In addition, since the ink is not discharged from the drain tank DT to the discharge flow path DCH, the outflow amount QD OUT is zero. Based on these conditions and equations (2) and (3), equation (4) can be obtained. ΔQF+ΔQD=QF IN … Formula (4)

[0118] The left side of equation (4) is the sum of the change amount ΔQF of the ink storage amount in the fill tank FT over a predetermined period and the change amount ΔQD of the ink storage amount in the drain tank DT over a predetermined period. This value (ΔQF+ΔQD) corresponds to the sum of the slope X of the detection value of the fill tank sensor 31 and the slope Y of the detection value of the drain tank sensor 32, based on the correspondence relationship shown in Figures 13(a) and 13(b). On the other hand, the right side of equation (4) is the flow rate of ink flowing from the supply flow path SCH into the fill tank FT, and is the flow rate of the HPM filter F HPM is equal to the flow rate Q of the

[0119] Therefore, the controller 700 obtains the slope X of the detection value of the fill tank sensor 31 and the slope Y of the detection value of the drain tank sensor 32 while sending the ink in the main tank 410 to the drain tank DT via the supply flow path SCH and the head flow path HCH without discharging the ink from the drain tank DT to the discharge flow path DCH. Then, the controller 700 calculates the slope X of the detection value of the fill tank sensor 31 and the slope Y of the detection value of the drain tank sensor 32 based on the sum of the obtained slopes X and Y. HPM The flow rate Q of the flow rate Q is estimated. The sum of the slope X and the slope Y is an example of a "value based on the first change amount and the second change amount." In addition to the simple sum of the slope X and the slope Y, the "value based on the first change amount and the second change amount" may be, for example, a value corrected by multiplying the slope X and / or the slope Y by a coefficient in order to further increase the accuracy of the estimated value of the flow rate Q.

[0120] The controller 700 may obtain the slope X of the detection value of the fill tank sensor 31 and the slope Y of the detection value of the drain tank sensor 32 while sending the ink in the fill tank FT to the main tank 410 through the head flow path HCH and the discharge flow path DCH. At this time, the controller 700 does not supply ink from the supply flow path SCH to the fill tank FT. In this case, the inflow amount QF IN becomes zero, and the outflow QF OUT and inflow QD IN Based on these conditions and equations (2) and (3), equation (5) can be obtained. -(ΔQF+ΔQD)=QD OUT … Formula (5)

[0121] The right side of equation (5) is the flow rate of ink flowing from the drain tank DT to the discharge flow path DCH, and the HPM filter F HPM Therefore, the controller 700 calculates the HPM filter F based on the sum of the obtained slopes X and Y. HPM The flow rate Q of the

[0122] In step S202, the controller 700 calculates the estimated HPM filter F HPM Based on the flow rate Q of the HPM filter F HPM The controller 700 calculates the life of the HPM filter F in a manner substantially identical to that in step S103 of the state determination process P100. HPM The lifetime of the material can be calculated.

[0123] Specifically, as shown in Fig. 16(a), the HPM filter F HPM The flow rate Q of the printer 1000 (and thus the HPM filter F HPM This is because the HPM filter F HPM Deterioration or accumulation of minute clogs occurs with use, and the HPM filter F HPM This is because the amount of ink flowing through the HPM filter F, in other words, the amount of ink flowing through the supply flow channel SCH and the discharge flow channel DCH, is reduced. HPM The flow rate Q is the threshold TH Q When the HPM filter F HPM can be considered to be in a state where it is no longer suitable for use.

[0124] Here, the current operating time is the operating time OH1, the HPM filter F HPM The flow rate Q is the threshold TH Q If the operating time at which the temperature drops to OH2 is the operating time, the period from operating time OH1 to operating time OH2 is the HPM filter F HPM Lifespan LT HPM is equivalent to.

[0125] In view of the above, the controller 700 uses the HPM filter F stored in the state determination process P200 executed so far. HPM Time series data of flow rate Q SD Q Based on the HPM filter F HPM Lifespan LT HPM The controller 700 estimates, for example, the time series data S. Q The life LT can be calculated by calculating the slope of the change in flow rate Q over time based on HMP Specifically, the controller 700 calculates the HPM filter F HPM Time series data of flow rate Q SD Q A straight line passing through the flow rate Q is calculated using a linear approximation method such as the least squares method, and the flow rate Q indicated by the straight line is set to the threshold value TH Q Then, find the point A2 that matches the HPM filter F HPM Lifespan LT HPM is calculated as the difference between the operating time OH2 indicated by point A2 and the current operating time OH1.

[0126] In step S203, the controller 700 calculates the filter life LT HPM is the first threshold TH1 HPM (An example of a "second filter threshold") Determine whether the first threshold TH1 is equal to or smaller than the first threshold TH2. HPM For example, it may be several months to several years.

[0127] The controller 700 determines the filter life LT HPM is the first threshold TH1 HPM If it is greater than the threshold (S203: NO), the HPM filter F HPM The display unit 900 displays information indicating that the HPM filter F is in a normal state (S206), and the state determination process P200 is terminated. HPM The information indicating that the condition of the filter is normal may be, for example, text information or an icon indicating that the condition is "normal." HPM is the first threshold TH1 HPM The HPM filter F HPM 13 is an example of a display of information indicating that the status is normal.

[0128] The controller 700 determines the filter life LT HPM is the first threshold TH1 HPM If it is equal to or less than the filter life LT (S203: YES), in step S204, HPM is the second threshold TH2 HPM (An example of a "second filter notification threshold value") HPM is the first threshold TH1 HPM The value is smaller than the above, and may be, for example, on the order of several days to several weeks.

[0129] The controller 700 determines the filter life LT HPM is the second threshold TH2 HPM If it is equal to or greater than the filter life LT calculated in step S202, HPM The controller 700 displays the filter life LT HPM is the second threshold TH2 HPM If it is smaller (S204: YES), the process proceeds to step S205, and an HPM maintenance alert (an example of a "notification regarding the second filter") is issued. Specifically, the controller 700 performs maintenance of the HPM 500 (specifically, for example, the HPM filter F HPM Information indicating that a replacement (or replacement of the battery) is required is displayed on the display unit 900. After that, the controller 700 ends the state determination process P200.

[0130] (2-2) State determination based on the rotation speed of pump P HPM filter F based on the rotation speed of the pump P HPM The printer 1000 is, for example, a printer in which the rotational speed of the pump P is feedback-controlled, and the HPM filter F HPM In the embodiment where the rotation speed of the pump P changes depending on the state of the pump P, the HPM filter F based on the rotation speed of the pump P is HPM In this embodiment, the controller 700 executes a state determination process P300 shown in the flowchart of FIG. 17 to determine the state of the HPM filter F HPM The controller 700 performs a state determination process P300 periodically (for example, once a day).

[0131] In step S301, the controller 700 acquires the rotation speed of the pump P. Specifically, for example, a signal indicating the rotation speed of the pump P is received from a sensor such as an encoder (not shown) built into the pump P.

[0132] In step S302, the controller 700 controls the HPM filter F based on the rotation speed of the pump P. HPM The controller 700 calculates the life of the HPM filter F in a manner substantially identical to that in step S103 of the state determination process P100. HPM The lifetime of the material can be calculated.

[0133] Specifically, as shown in FIG. 18(a), the rotation speed of the pump P is changed depending on the operating time of the printer 1000 (and thus the HPM filter F HPM This increases as the operating time of the HPM filter F increases. HPM Deterioration occurs with use, and the HPM filter F HPM This is because it becomes necessary to increase the rotation speed of the pump P in order to keep the amount of ink circulating through the pump constant. P When the temperature rises to , the HPM filter F HPM It can be considered that the HPM filter F is in an unusable state. The controller 700 determines whether the HPM filter F is in an unusable state based on, for example, the detection value of a flow meter (not shown) located in the supply flow path SCH, or the sum of the slope X of the detection value of the fill tank sensor 31 and the slope Y of the detection value of the drain tank sensor 32. HPM It can be seen that the amount of ink circulating is kept constant.

[0134] In view of the above, the controller 700 stores the time-series data SD P Based on the HPM filter F HPM Lifespan LT HPM The controller 700 estimates, for example, the time series data S. P By calculating the slope of the change in the rotation speed of the pump P over time based on HMP Specifically, for example, the controller 700 calculates the time series data SD of the rotation speed of the pump P as shown in FIG. P A straight line passing through the line is obtained by a linear approximation method such as the least squares method, and the value of the rotation speed indicated by the straight line is the threshold value TH P Then, find the point A3 that matches the HPM filter F HPM Lifespan LT HPM is calculated as the difference between the operating time OH2 indicated by point A3 and the current operating time OH1.

[0135] In step S303, the controller 700 calculates the filter life LT HPM is the first threshold TH1 HPM (An example of a "second filter threshold") Determine whether the first threshold TH1 is equal to or smaller than the first threshold TH2. HPM For example, it may be several months to several years.

[0136] The controller 700 determines the filter life LT HPM is the first threshold TH1 HPM If it is larger than the head filter F HPM The display unit 900 displays information indicating that the HPM filter F is in a normal state (S306), and the state determination process P300 is terminated. HPM The information indicating that the condition of the filter is normal may be, for example, text information or an icon indicating that the condition is "normal." HPM is the first threshold TH1 HPM The HPM filter F HPM 13 is an example of a display of information indicating that the status is normal.

[0137] The controller 700 determines the filter life LT HPM is the first threshold TH1 HPM If it is equal to or less than the filter life LT (S303: YES), in step S304, HPM is the second threshold TH2 HPM (An example of a "second filter notification threshold value") HPM is the first threshold TH1 HPM The value is smaller than the above, and may be, for example, on the order of several days to several weeks.

[0138] The controller 700 determines the filter life LT HPM is the second threshold TH2 HPM If it is equal to or greater than the filter life LT calculated in step S302 (S304: NO), HPM The controller 700 displays the filter life LT HPM is the second threshold TH2 HPM If it is smaller (S304: YES), in step S305, an HPM maintenance alert (an example of a "notification regarding the second filter") is issued. Specifically, the controller 700 performs maintenance of the HPM 500 (specifically, for example, the HPM filter F HPM Information indicating that a replacement (or replacement of the battery) is required is displayed on the display unit 900. Thereafter, the controller 700 ends the state determination process P300.

[0139] The advantageous effects of the printer 1000 and filter state determination of this embodiment are summarized below.

[0140] In the printer 1000 of this embodiment, the controller 700 executes a state determination step P100 and a state determination step P200 or a state determination step P300. HD Status and HPM filter F HPM The state of the head filter F can be determined independently of each other. HD and HPM filter F HPM It is possible to determine which of the filters is abnormal.

[0141] In the printer 1000 of this embodiment, the state determination process P100, the state determination process P200, or the state determination process P300 is executed using the liquid level detection unit 30 (i.e., the fill tank sensor 31 and the drain tank sensor 32) of the head system 100 and / or the rotation speed of the pump P of the HPM 500. HD HPM filter F HPM This is advantageous in terms of reducing the size of the printer 1000 and reducing the manufacturing costs of the printer 1000. HD HPM filter F HPM Since a dedicated structure for determining the state is not required, the flow path structure does not become complicated.

[0142] In the printer 1000 of this embodiment, the controller 700 judges whether the differential pressure PD is appropriately controlled (state judgment process P100, step S101), and when it is judged that the differential pressure PD is appropriately controlled, the controller 700 FD The life of the head filter H is calculated (state determination process P100, step S103). Therefore, the life can be calculated with higher accuracy. If the determination as to whether the differential pressure PD is appropriately controlled is not performed, the change in the flow rate of the head flow path HSC is not FD It is possible that this is not due to a change in the state of the air pressure regulator 600, but rather that the air pressure regulator 600 is not being appropriately controlled. This may result in a decrease in the accuracy, reliability, etc. of the calculated lifespan.

[0143] In the printer 1000 of this embodiment, the controller 700 judges whether the slope X of the detection value of the fill tank sensor 31 or the slope Y of the detection value of the drain tank sensor 32 has suddenly decreased in a short period of time (state judgment process P100, step S102). HD Therefore, the occurrence of clogging can be appropriately detected.

[0144] [Variations] In the above embodiment, the following modifications may be used.

[0145] (Variation 1) In the above embodiment, the controller 700 executes the state determination process P100 (FIG. 11) to determine the head filter F HD However, the head filter F HD There are various steps for carrying out the state determination, and they are not limited to those following the state determination process P100.

[0146] Specifically, for example, the controller 700 executes a state determination process P400 shown in FIG. HD The main difference between the state determination process P400 and the state determination process P100 is that the head filter F HD 19. The difference between the state determination process P400 and the state determination process P100 is that the display content on the display unit 900 is determined based on a comparison of the slope X of the detection value of the fill tank sensor 31 or the slope Y of the detection value of the drain tank sensor 32 with a threshold value, rather than a comparison of the life of the detection value of the fill tank sensor 31 with a threshold value. The main difference between the state determination process P400 and the state determination process P100 is that, when focusing on the flowchart of FIG. 11 and the flowchart of FIG. 19, steps S403 and S404 are performed instead of steps S103 to S105.

[0147] In the following, the state determination process P400 will be described using as an example a case where the slope Y of the detection value of the drain tank sensor 32 is used as a value indicating the flow rate of ink flowing through the head flow channel HCH. The state determination process P400 can also be performed in the same manner as described below when the slope X of the detection value of the fill tank sensor 31 is used as a value indicating the flow rate of ink flowing through the head flow channel HCH.

[0148] In step S401 of the state determination process P400, the controller 700 determines whether the pressure difference PD between the fill tank FT and the drain tank DT is appropriately controlled. Specifically, step S401 may be the same as step S101 of the state determination process P100.

[0149] If the controller 700 determines that the differential pressure PD is not appropriately controlled (step S401: NO), it displays information indicating that an abnormality has occurred in the control of the differential pressure PD on the display unit 900 (step S406), and terminates the state determination process P400.

[0150] When the controller 700 determines that the pressure difference PD is appropriately controlled (step S401: YES), it determines in step S402 whether the slope Y of the detection value of the drain tank sensor 32 has decreased significantly compared to the previous execution of the state determination process P400. Specifically, step S402 may be the same as step S102 of the state determination process P100. That is, the controller 700 checks whether the slope decrease amount ΔY is greater than or equal to the decrease amount threshold TH ΔY A check is made to see if it is smaller than the given value.

[0151] The controller 700 determines whether the inclination decrease amount ΔY is equal to or smaller than the decrease amount threshold TH ΔY If the number is equal to or greater than the number of the first filter (S402: NO), the process proceeds to step S407, and a head maintenance alert (an example of a "notification regarding the first filter") is issued. Specifically, the controller 700 performs maintenance of the head 43 (specifically, for example, the head filter F HD The display unit 900 displays information indicating that a head maintenance alert (replacement of the ink cartridge 41, replacement of the head 43, etc.) is necessary. Note that the head maintenance alert issued by the controller 700 in step S407 is based on a sudden decrease in the slope Y (i.e., the flow rate of ink flowing through the head flow channel HCH) and is considered to be of high urgency. Therefore, the controller 700 may display information urging the user to perform immediate replacement. After that, the controller 700 ends the state determination process P400.

[0152] The controller 700 determines whether the slope decrease amount ΔY is equal to or smaller than the decrease amount threshold TH ΔY If it is smaller than the initial value IV (S402: YES), in step S403, the slope Y of the detection value of the drain tank sensor 32 is set to the initial value IV Y Here, it is determined whether the initial value IV Y Head filter F HD is the value of the slope Y of the detection value of the drain tank sensor 32 at the start of use. Y For example, the new head filter F HD After the head filter F is attached to the head 43 or after a new head 43 is attached to the printer 1000, HD The measurement can be obtained by flowing ink onto the surface of the inkjet head.

[0153] The controller 700 determines whether the slope Y is equal to the initial value IV Y If it is equal to or greater than this (S403: NO), the head filter F HD The controller 700 displays information indicating that the state of the gradient Y is normal on the display unit 900 (S408), and ends the state determination process P400. Y If the gradient Y is smaller than the third threshold TH3 (S403: YES), in step S404, HD (An example of the "first filter notification threshold". The third threshold TH3 HD is the initial value IV Y Determine whether the value is less than or equal to the given value (i.e., a smaller value).

[0154] Slope Y is the third threshold TH3 HD If it is greater than the head filter F (S404: NO), the controller 700 in step S409 HD The life of the head filter F is calculated and the calculated life is displayed on the display unit 900. HD The calculation of the filter life LT can be performed in the same manner as in step S103 of the state determination process P100. HD may be displayed as the life of the head 43. After executing step S409, the controller 700 ends the state determination process P400.

[0155] Slope Y is the third threshold TH3 HD If the condition is as follows (S404: YES), the controller 700 performs a head maintenance alert (an example of a "notification regarding the first filter") in step S405. Specifically, the controller 700 performs maintenance of the head 43 (specifically, for example, the head filter F HD The display unit 900 displays information indicating that a head maintenance alert (replacement of the head 41, replacement of the head 42, etc.) is necessary. Note that the head maintenance alert performed by the controller 700 in step S405 is based on a predicted gradual decrease in the slope Y (i.e., the flow rate of ink flowing through the head flow channel HCH), and is considered to be less urgent than the head maintenance alert performed in step S407. Therefore, the controller 700 may perform a display in a manner different from that in step S407, and may display, for example, information urging the user to perform replacement in the near future. After that, the controller 700 ends the state determination process P400.

[0156] (Variation 2) In the above embodiment, the controller 700 executes the state determination process P200 (FIG. 15) to determine the HPM filter F HPM HPM filter F based on flow rate Q HPM However, the HPM filter F HPM HPM filter F based on flow rate Q HPM There are various steps for carrying out the state determination, and they are not limited to those following the state determination process P200.

[0157] Specifically, for example, the controller 700 executes a state determination process P500 shown in FIG. 20 to determine whether the HPM filter F HPM The main difference between the state determination process P500 and the state determination process P200 is the HPM filter F HPM Instead of comparing the life span and threshold value of the HPM filter F HPM 15 and 20, the state determination process P500 determines the display content for the display unit 900 based on a comparison of the flow rate Q with a threshold value. The main difference between the state determination process P500 and the state determination process P200 is that, when focusing on the flowcharts of Fig. 15 and 20, steps S502 and S503 are performed instead of steps S202 to S204.

[0158] In step S501 of the state determination process P500, the controller 700 detects the HPM filter F HPM The flow rate Q of the flow rate .DELTA..times ...

[0159] In step S502, the controller 700 calculates the HPM filter F estimated in step S501. HPM The flow rate Q is the initial value IV Q Here, it is determined whether the initial value IV Q What is HPM filter F HPM The value of flow rate Q at the start of use of the initial value IV Q For example, the new HPM filter F HPM After installing the HPM500, the HPM filter F HPM The measurement can be obtained by flowing ink onto the surface of the inkjet head.

[0160] The controller 700 determines whether the flow rate Q is equal to the initial value IV Q If it is equal to or greater than this (S502: NO), the HPM filter F HPM The controller 700 displays information indicating that the flow rate Q is normal on the display unit 900 (S505), and ends the state determination process P500. Q If the flow rate Q is smaller than the third threshold value TH3 (S502: YES), in step S503, HPMQ (An example of the "second filter notification threshold". The third threshold TH3 HPMQ is the initial value IV Q Determine whether the value is less than or equal to the given value (i.e., a smaller value).

[0161] Flow rate Q is the third threshold TH3 HPMQ If it is greater than the threshold (S503: NO), the controller 700 in step S506 selects the HPM filter F HPM The life of the HPM filter F is calculated and the calculated life is displayed on the display unit 900. HPM The calculation of the life span can be performed in the same manner as in step S202 of the state determination process P200. After executing step S506, the controller 700 ends the state determination process P500.

[0162] Flow rate Q is the third threshold TH3 HPMQ If the condition is as follows (S503: YES), the controller 700 performs a head maintenance alert (an example of a "notification regarding the second filter") in step S504. HPM Information indicating that a replacement (or replacement of the battery) is necessary is displayed on the display unit 900. After that, the controller 700 ends the state determination process P500.

[0163] (Variation 3) In the above embodiment, the controller 700 executes the state determination process P300 (FIG. 17) to determine the HPM filter F based on the rotation speed of the pump P. HPM However, the HPM filter F based on the rotation speed of the pump P is HPM There are various steps for carrying out the state determination, and they are not limited to those following the state determination process P300.

[0164] Specifically, for example, the controller 700 executes a state determination process P600 shown in FIG. 21 to determine whether the HPM filter F HPM The main difference between the state determination process P600 and the state determination process P300 is the HPM filter F HPM 21, the main difference between the state determination process P600 and the state determination process P300 is that steps S602 and S603 are performed instead of steps S302 to S304.

[0165] In step S601 of the state determination process P600, the controller 700 calculates the rotation speed of the pump P. The specific procedure of step S601 may be the same as that of step S301 of the state determination process P300.

[0166] In step S602, the controller 700 sets the rotation speed of the pump P calculated in step S601 to the initial value IV P Here, it is determined whether the initial value IV P What is HPM filter F HPM is the value of the rotation speed of the pump P at the start of use. P For example, the new HPM filter F HPM After installing the HPM500, the HPM filter F HPM The measurement can be obtained by flowing ink onto the surface of the inkjet head.

[0167] The controller 700 sets the rotation speed of the pump P to an initial value IV P If it is equal to or less than (S602: NO), the HPM filter F HPM The controller 700 displays information indicating that the rotational speed of the pump P is normal on the display unit 900 (S605), and ends the state determination process P600. P If the rotation speed of the pump P is greater than the third threshold value TH3 (S602: YES), in step S603, HPMP (An example of the "second filter notification threshold". The third threshold TH3 HPMP is the initial value IV P Determine whether the value is greater than or equal to the

[0168] The rotation speed of the pump P is the third threshold TH3 HPMP If it is smaller (S603: NO), the controller 700 in step S606 adjusts the HPM filter F HPM The life of the HPM filter F is calculated and the calculated life is displayed on the display unit 900. HPM The calculation of the life span can be performed in the same manner as in step S302 of the state determination process P300. After executing step S606, the controller 700 ends the state determination process P600.

[0169] The rotation speed of the pump P is the third threshold TH3 HPMP If the number is equal to or greater than the number of the HPM filters (S603: YES), the controller 700 performs a head maintenance alert (an example of a "notification related to the second filter") in step S604. HPM Information indicating that a replacement (or replacement of the battery) is necessary is displayed on the display unit 900. Thereafter, the controller 700 ends the state determination process P600.

[0170] (Other variations) In the printer 1000 of the above embodiment and modified example, the controller 700 periodically executes the status determination processes P100 to P600. However, this is not limited to this. The controller 700 can execute at least one of the status determination processes P100 to P600 at any timing. The arbitrary timing may be, for example, the timing when a predetermined process (maintenance process, etc.) is completed, the timing when an instruction to execute a status determination process is received from the user, etc.

[0171] In the printer 1000 of the above embodiment and modified example, the controller 700 visually displays and notifies the information in the state determination processes P100 to P600 via the display unit 900, but is not limited to this. The information may be displayed or notified in any manner that can be perceived by the user, and may be audibly displayed via an audio display unit (not shown), for example.

[0172] In the above embodiment and modified examples, each step of the state determination process P100 to P600 may be omitted as appropriate. Specifically, for example, steps S101 and S102 of the state determination process P100 and steps S401 and S402 of the state determination process P400 may not be executed.

[0173] In the above embodiment and modified example, the fill tank sensor 31 and the drain tank sensor 32 provided in the liquid level detection unit 30 of the head system 100 are each a capacitance type liquid level detection sensor, but are not limited to this. The fill tank sensor 31 and the drain tank sensor 32 may be any liquid level detection sensor (for example, a float type, an optical type, a radio wave type, etc.) that can detect the position of the liquid level in the fill tank FT and the drain tank DT, respectively. Furthermore, the fill tank sensor 31 and the drain tank sensor 32 are not limited to liquid level detection sensors, and may be any liquid volume sensor that can detect the liquid volume in the fill tank FT and the drain tank DT, respectively. The liquid volume sensor may be any liquid volume sensor, and may be configured to detect the liquid volume in the fill tank FT and the drain tank DT based on the mass of the liquid in the fill tank FT and the drain tank DT, for example. The liquid level detection sensor is one aspect of the liquid volume sensor.

[0174] In the above embodiment and modified example, the HPM filter F is disposed between the pump P and the filter tank FT in the supply flow path SCH of the HPM 500. HPM In the supply flow path SCH, a HPM filter is provided between the main tank 410 and the pump P. HPM In addition, a head filter F HD The HPM filter F is placed at an arbitrary position in the head flow channel HCH. HPM may be disposed at any position within the supply channel SCH.

[0175] In the above embodiment and modified examples, the controller 700 included in the printer 1000 executes the state determination processes P100 to P600, but this is not limited to the above. An external device (e.g., a PC) different from the printer 1000 may function as a controller and execute the state determination processes P100 to P600. In this case, the printer 1000 and the external device configure a liquid ejection system. Also, display and notification of information in the state determination processes P100 to P600 may be performed via the external device instead of the display unit 900.

[0176] The above describes the embodiment and modified examples using as an example a case where an image is formed on a medium PM by ejecting ink from the head system 100. The head system 100 may be a liquid ejection system that ejects any liquid for forming an image, and the medium PM on which the image is formed may be, for example, paper, cloth, resin, etc.

[0177] The embodiments described in this specification are illustrative in all respects and should not be considered as limiting. For example, the number and configuration of the head systems 100 in the printer 1000 may be changed. The number of colors that the printer 1000 can print simultaneously is not limited, and the printer 1000 may be configured to be capable of single-color printing only. The number and arrangement of the individual flow channels iCH may also be changed as appropriate. The technical features described in each embodiment and modification may be combined with each other. Instead of the head system 100, the printer 1000 may be provided with a serial head that ejects liquid while moving in the scanning direction.

[0178] As long as the characteristics of the present invention are maintained, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0179] (Additional Note) It will be understood by those skilled in the art that the above-described embodiments and their modifications are specific examples of the following aspects.

[0180] (Item 1) A liquid ejection system for ejecting a liquid, comprising: a head configured to eject the liquid, the head having a supply port for supplying the liquid to the head and a discharge port for discharging the liquid from the head; A supply tank connected to the supply port; A discharge tank connected to the discharge port; a pump for causing the liquid to flow in a supply flow path that supplies the liquid to the supply tank; a first filter located in a head flow path extending from the supply tank through the head to the discharge tank; A second filter located in the supply flow path; a first liquid amount sensor for detecting the amount of the liquid stored in the supply tank; a second liquid amount sensor for detecting the amount of the liquid stored in the discharge tank; a controller that determines a state of the first filter based on a first change amount, which is an amount of change in a detection value of the first liquid quantity sensor over a predetermined period of time, or a second change amount, which is an amount of change in a detection value of the second liquid quantity sensor over a predetermined period of time, and that determines the state of the second filter based on a value based on the first change amount and the second change amount or on the rotation speed of the pump.

[0181] (Item 2) The liquid ejection system described in item 1, wherein the controller issues an alert regarding the first filter when the amount of decrease in the newly acquired first change amount compared to the previously acquired first change amount is equal to or greater than a decrease amount threshold, or when the amount of decrease in the newly acquired second change amount compared to the previously acquired second change amount is equal to or greater than the decrease amount threshold.

[0182] (Item 3) The liquid ejection system described in item 1 or 2, wherein the controller calculates the life of the first filter based on the first change amount or the second change amount, and displays that the condition of the first filter is normal if the calculated life is greater than a threshold value for the first filter.

[0183] (Item 4) The liquid ejection system described in item 3, wherein the controller calculates the life of the first filter when the amount of decrease in the newly acquired first change amount compared to the previously acquired first change amount is smaller than a decrease amount threshold, or when the amount of decrease in the newly acquired second change amount compared to the previously acquired second change amount is smaller than a decrease amount threshold.

[0184] (Item 5) The liquid ejection system described in item 3 or 4, wherein the controller displays the calculated lifespan when the calculated lifespan is equal to or less than the first filter threshold and equal to or greater than a first filter warning threshold that is smaller than the first filter threshold.

[0185] (Item 6) The liquid ejection system according to any one of items 3 to 5, wherein the controller issues a notification regarding the first filter when the calculated life is smaller than a first filter notification threshold that is smaller than the first filter threshold.

[0186] (Item 7) The liquid ejection system described in item 1 or 2, wherein the controller issues an alert regarding the first filter when the first change amount or the second change amount is equal to or less than a first filter alert threshold that is smaller than an initial value of the first change amount or the second change amount.

[0187] (Item 8) The liquid ejection system described in any one of items 1, 2, and 7, wherein the controller calculates a lifespan of the first filter when the first change amount or the second change amount is equal to or less than an initial value of the first change amount or the second change amount and is greater than a first filter warning threshold value that is smaller than the initial value, and displays the calculated lifespan.

[0188] (Item 9) The liquid ejection system according to any one of items 3 to 6 and 8, wherein the controller calculates a lifespan of the first filter based on a gradient of a change over time in the first amount of change or the second amount of change.

[0189] (Item 10) The supply flow path is connected to a storage tank, the discharge tank is connected to the storage tank via a discharge flow path that sends the liquid in the discharge tank to the storage tank, The liquid ejection system of any one of items 1 to 9, wherein the controller determines whether or not a differential pressure between the supply tank and the discharge tank is normal based on a comparison between the second amount of change when the liquid stored in the supply tank is sent to the discharge tank via the head flow path and the second amount of change when the liquid stored in the storage tank is sent to the discharge tank via the supply flow path and the head flow path, or based on a comparison between the first amount of change when the liquid stored in the supply tank is sent to the discharge tank via the head flow path and the first amount of change when the liquid stored in the supply tank is sent to the storage tank via the head flow path and the discharge flow path.

[0190] (Item 11) The liquid ejection system described in any one of items 1 to 10, wherein the controller calculates the life of the second filter based on a value based on the first change amount and the second change amount, and displays that the condition of the second filter is normal if the calculated life is greater than a threshold value for the second filter.

[0191] (Item 12) The liquid ejection system described in item 11, wherein the controller displays the calculated lifespan when the calculated lifespan is equal to or less than the second filter threshold and equal to or greater than a second filter warning threshold that is smaller than the second filter threshold.

[0192] (Item 13) 13. The liquid ejection system according to item 11 or 12, wherein the controller issues a notification regarding the second filter when the calculated life is smaller than a second filter notification threshold that is smaller than the second filter threshold.

[0193] (Item 14) The liquid ejection system described in any one of items 1 to 10, wherein the controller issues an alert regarding the second filter when a value based on the first change amount and the second change amount is equal to or less than a second filter alert threshold which is smaller than an initial value of the value based on the first change amount and the second change amount.

[0194] (Item 15) The liquid ejection system described in any one of items 1 to 10 and 14, wherein the controller calculates the life of the second filter and displays the calculated life when a value based on the first change amount and the second change amount is less than or equal to an initial value of the value based on the first change amount and the second change amount and is greater than a second filter warning threshold value that is smaller than the initial value.

[0195] (Item 16) The liquid ejection system according to any one of items 11 to 13 and 15, wherein the controller calculates a lifespan of the second filter based on a gradient of a change over time of a value based on the first amount of change and the second amount of change.

[0196] (Item 17) The liquid ejection system according to any one of items 1 to 10, wherein the controller calculates the life of the second filter based on the rotation speed of the pump, and displays that the condition of the second filter is normal if the calculated life is greater than a threshold value for the second filter.

[0197] (Item 18) The liquid ejection system described in item 17, wherein the controller displays the calculated lifespan when the calculated lifespan is equal to or less than the second filter threshold and equal to or greater than a second filter warning threshold that is smaller than the second filter threshold.

[0198] (Item 19) 19. The liquid ejection system according to item 17 or 18, wherein the controller issues a notification regarding the second filter when the calculated life is smaller than a second filter notification threshold which is smaller than the second filter threshold.

[0199] (Item 20) 11. The liquid ejection system according to any one of items 1 to 10, wherein the controller issues a notification regarding the second filter when the rotation speed of the pump is equal to or greater than a second filter notification threshold value that is greater than an initial value of the rotation speed of the pump.

[0200] (Item 21) The liquid ejection system according to any one of items 1 to 10 and 20, wherein the controller calculates the life of the second filter and displays the calculated life when the pump rotation speed is equal to or greater than an initial value of the pump rotation speed and is smaller than a second filter warning threshold value that is greater than the initial value.

[0201] (Item 22) The liquid ejection system according to any one of items 17 to 19 and 21, wherein the controller calculates the life of the second filter based on a gradient of a change over time in the rotation speed of the pump.

[0202] (Item 23) A filter state determination method executed by a controller of a liquid ejection system that ejects liquid, comprising: The liquid ejection system includes: a head configured to eject the liquid, the head having a supply port for supplying the liquid to the head and a discharge port for discharging the liquid from the head; A supply tank connected to the supply port; A discharge tank connected to the discharge port; a pump for causing the liquid to flow in a supply flow path that supplies the liquid to the supply tank; a first filter located in a head flow path extending from the supply tank through the head to the discharge tank; A second filter located in the supply flow path; a first liquid amount sensor for detecting the amount of the liquid stored in the supply tank; a second liquid amount sensor for detecting the amount of the liquid stored in the discharge tank; determining a state of the first filter based on a first change amount, which is an amount of change in a detection value of the first liquid quantity sensor during a predetermined period, or a second change amount, which is an amount of change in a detection value of the second liquid quantity sensor during a predetermined period; A filter state determining method comprising: determining a state of the second filter based on a value based on the first amount of change and the second amount of change or on a rotation speed of the pump. [Explanation of symbols]

[0203] 20 Subtank 30 Liquid level detector 31 Fill Tank Sensor 32 Drain tank sensor 40 Head mechanism 43 Head 100 Head System 400 Ink Tank 500 HPM 700 Controller 1000 Printers DT Drain Tank F HD Head Filter F HPM HPM Filter FT Fill Tank P-Pump

Claims

1. A liquid ejection system for ejecting a liquid, comprising: a head configured to eject the liquid, the head having a supply port for supplying the liquid to the head and a discharge port for discharging the liquid from the head; A supply tank connected to the supply port; A discharge tank connected to the discharge port; a pump for causing the liquid to flow in a supply flow path that supplies the liquid to the supply tank; a first filter located in a head flow path extending from the supply tank through the head to the discharge tank; A second filter located in the supply flow path; a first liquid amount sensor for detecting an amount of the liquid stored in the supply tank; a second liquid amount sensor for detecting the amount of the liquid stored in the discharge tank; a controller that determines a state of the first filter based on a first change amount, which is the amount of change in the detection value of the first liquid volume sensor over a predetermined period of time, or a second change amount, which is the amount of change in the detection value of the second liquid volume sensor over a predetermined period of time, and that determines the state of the second filter based on a value based on the first change amount and the second change amount or the rotation speed of the pump.

2. The liquid ejection system of claim 1, wherein the controller issues an alert regarding the first filter when the amount of decrease in the newly acquired first change amount compared to the previously acquired first change amount is equal to or greater than a decrease amount threshold, or when the amount of decrease in the newly acquired second change amount compared to the previously acquired second change amount is equal to or greater than the decrease amount threshold.

3. The liquid ejection system of claim 1, wherein the controller calculates a lifespan of the first filter based on the first change amount or the second change amount, and displays that the condition of the first filter is normal if the calculated lifespan is greater than a threshold value for the first filter.

4. The liquid ejection system of claim 3, wherein the controller calculates the life of the first filter when the amount of decrease in the newly acquired first change amount compared to the previously acquired first change amount is smaller than a decrease amount threshold, or when the amount of decrease in the newly acquired second change amount compared to the previously acquired second change amount is smaller than a decrease amount threshold.

5. The liquid ejection system according to claim 3 , wherein the controller displays the calculated lifespan when the calculated lifespan is equal to or less than the first filter threshold and equal to or greater than a first filter warning threshold that is smaller than the first filter threshold.

6. The liquid ejection system according to claim 3 , wherein the controller issues a notification regarding the first filter when the calculated life is smaller than a first filter notification threshold that is smaller than the first filter threshold.

7. The liquid ejection system of claim 1 , wherein the controller issues an alert regarding the first filter when the first change amount or the second change amount is equal to or less than a first filter alert threshold that is smaller than an initial value of the first change amount or the second change amount.

8. The liquid ejection system of claim 1, wherein the controller calculates a life of the first filter when the first change amount or the second change amount is less than an initial value of the first change amount or the second change amount and is greater than a warning threshold for a first filter that is smaller than the initial value, and displays the calculated life.

9. The liquid ejection system according to claim 3 , wherein the controller calculates the life of the first filter based on a gradient of the change over time of the first change amount or the second change amount.

10. The supply flow path is connected to a storage tank, the discharge tank is connected to the storage tank via a discharge flow path that sends the liquid in the discharge tank to the storage tank, The liquid ejection system of claim 1, wherein the controller determines whether or not the differential pressure between the supply tank and the discharge tank is normal based on a comparison between the second amount of change when the liquid stored in the supply tank is sent to the discharge tank via the head flow path and the second amount of change when the liquid stored in the storage tank is sent to the discharge tank via the supply flow path and the head flow path, or based on a comparison between the first amount of change when the liquid stored in the supply tank is sent to the discharge tank via the head flow path and the first amount of change when the liquid stored in the supply tank is sent to the storage tank via the head flow path and the discharge flow path.

11. A liquid ejection system described in any one of claims 1 to 10, wherein the controller calculates the life of the second filter based on a value based on the first change amount and the second change amount, and displays that the condition of the second filter is normal if the calculated life is greater than a threshold value for the second filter.

12. The liquid ejection system according to claim 11 , wherein the controller displays the calculated lifespan when the calculated lifespan is equal to or less than the second filter threshold and equal to or greater than a second filter warning threshold that is smaller than the second filter threshold.

13. The liquid ejection system according to claim 11 , wherein the controller issues a notification regarding the second filter when the calculated life is smaller than a second filter notification threshold that is smaller than the second filter threshold.

14. A liquid ejection system described in any one of claims 1 to 10, wherein the controller issues an alert regarding the second filter when a value based on the first change amount and the second change amount is equal to or less than a second filter alert threshold value which is smaller than an initial value of the value based on the first change amount and the second change amount.

15. A liquid ejection system described in any one of claims 1 to 10, wherein the controller calculates the life of the second filter and displays the calculated life when a value based on the first change amount and the second change amount is less than or equal to an initial value of the value based on the first change amount and the second change amount and is greater than a warning threshold for a second filter that is smaller than the initial value.

16. The liquid ejection system according to claim 11 , wherein the controller calculates the life of the second filter based on a gradient of a change over time of a value based on the first amount of change and the second amount of change.

17. A liquid ejection system described in any one of claims 1 to 10, wherein the controller calculates the life of the second filter based on the rotation speed of the pump, and displays that the condition of the second filter is normal if the calculated life is greater than a threshold value for the second filter.

18. The liquid ejection system according to claim 17 , wherein the controller displays the calculated lifespan when the calculated lifespan is equal to or less than a second filter threshold and equal to or greater than a second filter warning threshold that is smaller than the second filter threshold.

19. The liquid ejection system according to claim 17 , wherein the controller issues a notification regarding the second filter when the calculated life is smaller than a second filter notification threshold which is smaller than the second filter threshold.

20. The liquid ejection system according to any one of claims 1 to 10, wherein the controller issues an alert regarding the second filter when the rotation speed of the pump is equal to or greater than a second filter alert threshold value that is greater than an initial value of the rotation speed of the pump.

21. A liquid ejection system according to any one of claims 1 to 10, wherein the controller calculates the life of the second filter and displays the calculated life when the pump rotation speed is equal to or greater than an initial value of the pump rotation speed and is smaller than a second filter warning threshold value that is greater than the initial value.

22. The liquid ejection system according to claim 17 , wherein the controller calculates the life of the second filter based on a slope of a change over time in the rotation speed of the pump.

23. A filter state determination method executed by a controller of a liquid ejection system that ejects liquid, comprising: The liquid ejection system includes: a head configured to eject the liquid, the head having a supply port for supplying the liquid to the head and a discharge port for discharging the liquid from the head; A supply tank connected to the supply port; A discharge tank connected to the discharge port; a pump for causing the liquid to flow in a supply flow path that supplies the liquid to the supply tank; a first filter located in a head flow path extending from the supply tank through the head to the discharge tank; A second filter located in the supply flow path; a first liquid amount sensor for detecting an amount of the liquid stored in the supply tank; a second liquid amount sensor for detecting the amount of the liquid stored in the discharge tank; determining a state of the first filter based on a first change amount, which is an amount of change in a detection value of the first liquid quantity sensor during a predetermined period, or a second change amount, which is an amount of change in a detection value of the second liquid quantity sensor during a predetermined period; A filter state determining method comprising: determining a state of the second filter based on a value based on the first amount of change and the second amount of change or on a rotation speed of the pump.

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