Liquid discharge system and valve state determination method

Abstract

The present invention provides a liquid discharge system which realizes, at low cost, a configuration for determining a state of a valve.　The liquid discharge system comprises: a head; a first flow path; a second flow path that partially overlaps with the first flow path; a first valve that opens and closes the first flow path and the second flow path at an overlapping section at which the first flow path and the second flow path overlap; a second valve that opens and closes the first flow path at a position which is different from the overlapping section; a third valve that opens and closes the second flow path at a position which is different from the overlapping section; a first flow rate detector that detects the flow rate of a liquid flowing through the first flow path; a second flow rate detector that detects the flow rate of the liquid flowing through the second flow path; and a controller that, on the basis of a detected value of the first flow rate detector and / or a detected value of the second flow rate detector, determines whether or not there is an abnormality and / or predicts the service life with regard to at least one of the first valve, the second valve, and the third valve.

Description

Liquid ejection system and valve state determination method

[0001] The present invention relates to a liquid ejection system and a valve state determination method.

[0002] Liquid ejection systems are used to form images on a medium (such as paper) by ejecting a liquid (such as ink) from a head having nozzles onto the medium. In such liquid ejection systems, the supply of liquid to the head and the discharge of liquid from the head are performed by switching the open / close state of a valve provided in the flow path.

[0003] In a liquid ejection system equipped with a valve, it is desirable to determine the state of the valve as needed. Patent Document 1 discloses a method for determining the state of a valve, in which a valve open command is issued to at least one of a supply valve and a recovery valve connected to a single liquid ejection means, and whether the valve that is the target of the valve open command is operating normally is determined based on pressure changes in the supply flow path and the recovery flow path. Patent Document 1 requires multiple pressure sensors to determine the state of a single valve.

[0004] JP 2011-68033 A

[0005] In a system such as that disclosed in Patent Document 1, which requires multiple pressure sensors to determine the state of a single valve, it is difficult to provide a configuration for determining the valve state at low cost, and this becomes even more difficult as the number of valves to be determined increases.

[0006] An object of the present invention is to provide a liquid ejection system in which a configuration for determining the state of a valve is realized at low cost, and a valve state determination method that can determine the state of a valve at low cost.

[0007] According to a first aspect of the present invention, there is provided a liquid ejection system for ejecting a liquid, comprising: a head configured to eject the liquid; a first flow path that supplies the liquid to the head and / or discharges the liquid from the head; a second flow path that supplies the liquid to the head and / or discharges the liquid from the head, the second flow path partially overlapping with the first flow path; a first valve that opens and closes the first flow path and the second flow path at an overlapping portion between the first flow path and the second flow path; a second valve that opens and closes the first flow path at a position different from the overlapping portion; a third valve that opens and closes the second flow path at a position different from the overlapping portion; a first flow rate detector that detects a flow rate of the liquid flowing through the first flow path; a second flow rate detector that detects the flow rate of the liquid flowing through the second flow path; and a controller that determines whether or not there is an abnormality and / or predicts a lifespan of at least one of the first valve, the second valve, and the third valve based on a detection value of the first flow rate detector and / or a detection value of the second flow rate detector.

[0008] According to a second aspect of the present invention, there is provided a valve state determination method executed by a controller of a liquid ejection system that ejects liquid, the liquid ejection system having: a head configured to eject the liquid; a first flow path that supplies the liquid to the head and / or discharges the liquid from the head; a second flow path that supplies the liquid to the head and / or discharges the liquid from the head, the second flow path being a part that overlaps with the first flow path; a first valve that opens and closes the first flow path and the second flow path at an overlapping portion between the first flow path and the second flow path; a second valve that opens and closes the first flow path at a position different from the overlapping portion; a third valve that opens and closes the second flow path at a position different from the overlapping portion; a first flow rate detector that detects a flow rate of the liquid flowing through the first flow path; and a second flow rate detector that detects the flow rate of the liquid flowing through the second flow path, and the valve state determination method is provided that determines whether or not there is an abnormality and / or predicts a lifespan of at least one of the first valve, the second valve, and the third valve based on a detection value of the first flow rate detector and / or a detection value of the second flow rate detector.

[0009] The liquid ejection system of the present invention allows the manufacturer of the system to realize a configuration for determining the state of the valve at low cost, and the valve state determination method of the present invention allows the practitioner of the method to determine the state of the valve at low cost.

[0010] FIG. 1 is a schematic diagram of a printer according to an embodiment. FIG. 2 is a perspective view of a head system. FIG. 3 is a side view of a housing of the head system. FIG. 4 is an exploded perspective view of a subtank. FIG. 5 is a bottom view of the subtank. FIG. 6 is a perspective view of the right end portion of the subtank and a liquid level detector attached to the subtank. FIG. 7 is a perspective view of a head module. FIG. 8 is a plan view of the head. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8. FIG. 10 is a schematic diagram showing the flow path configuration of an HPM (Hydraulic Pneumatics Module). FIG. 11 is a schematic diagram showing the HPM forming a supply flow path. FIG. 12 is a schematic diagram showing the HPM forming a circulation flow path. FIG. 13 is a schematic diagram showing the HPM forming a discharge flow path. FIG. 14(a) is a schematic diagram illustrating a valve in an open state. FIG. 14(b) is a schematic diagram illustrating the valve in a closed state. FIG. 15 is a flowchart showing the procedure for the head condition determination process. FIG. 16 is a flowchart showing the procedure for the flow rate detection step. FIG. 17 is a graph showing temporal fluctuations in the detection values ​​of the fill tank sensor and the drain tank sensor. FIG. 18(a) is a graph illustrating the relationship between changes in the amount of ink stored in the fill tank and the slope of the detection value of the fill tank sensor. FIG. 18(b) is a graph illustrating the relationship between changes in the amount of ink stored in the drain tank and the slope of the detection value of the drain tank sensor. FIGS. 19(a) and 19(b) are graphs showing the relationship between the printer's operating time and the flow rate of the flow path. FIG. 19(a) shows the decrease in flow rate due to clogging of the HPM filter. FIG. 19(b) shows the decrease in flow rate due to clogging of the HPM filter before time T1, and the decrease in flow rate due to clogging of the HPM filter and valve deterioration after time T2. FIG. 20 is a flowchart showing the procedure for the valve abnormality determination step. FIG. 21 is a flowchart showing the procedure for the valve abnormality determination step. FIG. 22 is a flowchart showing the procedure for the flow rate abnormality determination step. Fig. 23 is a graph illustrating a process of calculating an approximate line based on past detected values ​​for the flow rate, and a process of calculating an estimated value based on the approximate line. Fig. 24 is a flowchart illustrating the procedure of a valve life prediction process.Fig. 25 is a flowchart showing the procedure of the life prediction process. Fig. 26(a) is a graph illustrating the process of calculating an approximation line for the flow rate based on past detected values ​​and the process of calculating an estimated value based on the approximation line. Fig. 26(b) is a graph illustrating the process of calculating a new approximation line for the flow rate in accordance with changes in the rate of decrease. Fig. 27 is a graph illustrating an example of a method for calculating a predicted value for the valve life. Fig. 28 is a graph showing the change in flow rate when a large foreign object becomes clogged in the HPM filter at time T2.

[0011] [Embodiment] A printer 1000 (an example of a "liquid ejection system") according to an embodiment will be described with reference to Figs.

[0012] 1, the printer 1000 mainly includes four head systems 100, a platen 200, transport rollers 301 and 302, an ink tank 400, an HPM (Hydraulic Pneumatics Module) 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.

[0013] 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. Also, the direction extending in the horizontal plane and perpendicular to the transport direction is referred to as the medium width direction.

[0014] 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.

[0015] The frame 100a supports the four head systems 100 so that the front-to-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 the platen 200.

[0016] The platen 200 is a plate-like member that supports the medium PM from the side opposite (below) the head system 100 when ink (an example of "liquid") is ejected from the head system 100 toward the medium PM.

[0017] The transport rollers 301 and 302 are arranged to sandwich the platen 200 in the transport direction. The transport rollers 301 and 302 function as a transport device that sends the medium PM in the transport direction in a predetermined manner when the head system 100 forms an image on the medium PM.

[0018] The ink tank 400 is divided into four main tanks 410 so as 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.

[0019] 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 HPMs 500 will be described later.

[0020] 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. The four types of ink are, for example, cyan ink, magenta ink, yellow ink, and black ink. In this embodiment, the ink may be UV ink.

[0021] The air pressure regulator 600 is a mechanism, such as a pump, that adjusts the pressure inside the subtank 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 in FIG. 1 as a representative example).

[0022] 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 a Field Programmable Gate Array (FPGA), an Electrically Erasable Programmable Read-Only Memory (EEPROM®), a Random Access Memory (RAM), etc. The controller 700 may also include a Central Processing Unit (CPU), an Application Specific Integrated Circuit (ASIC), etc. 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 external device, and controls each part of the printer 1000 based on print data sent from the external device.

[0023] The display unit 900 is a device that visually presents information to the user, and is specifically, for example, a liquid crystal monitor.

[0024] 2, each of the four head systems 100 mainly comprises a housing 10, subtanks 20 (an example of a "tank"), a liquid level detection unit 30, ten head modules 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 will focus on one of the four.

[0025] In the following description, the direction in which the ten head modules 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 modules 40 and the sub-tanks 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.

[0026] 2 are 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 are the left and right sides in the width direction. Regarding the up-down direction, the side where the sub-tanks 20 are located relative to the ten head modules 40 is the upper side, and the opposite side is the lower side.

[0027] 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 .

[0028] <Housing 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.

[0029] The first housing 11 has a top panel 11a, a bottom panel 11b, a front wall (not shown in FIG. 2 to show the interior of the first housing 11), a rear wall 11d, a left wall 11e, and a right wall 11f. A space S1 is defined inside the first housing 11 and is surrounded by the top panel 11a, the bottom panel 11b, the front wall, the rear wall 11d, the left wall 11e, and the right wall 11f.

[0030] 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.

[0031] As shown in Fig. 3, a power connector CN is provided at the top of the left wall 11e, and two air vents AP10 are provided below the power connector CN, aligned in the front-to-rear direction. Two ink vents IP10 are provided below the two air vents AP10, aligned in the front-to-rear direction. The power connector CN, the two air vents AP10, and the two ink vents IP10 are not shown in Fig. 2.

[0032] 2 , the second housing 12 has a top plate 12 a, a bottom plate 12 b, a front wall 12 c, a rear wall 12 d, a left wall 12 e, and a right wall 12 f. When the second housing 12 is attached to the first housing 11, the bottom plate 12 b of the second housing 12 abuts against the second region 11 a2 of the top plate 11 a of the first housing 11.

[0033] <Subtank 20> The subtank 20 receives and stores ink supplied to the head system 100. The ink stored in the subtank 20 is distributed to each of the multiple head modules 40.

[0034] 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.

[0035] 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 underside of the bottom plate 23.

[0036] The main body 21 is formed of resin, for example, and has a front wall 21c and a rear wall 21d extending along a plane perpendicular to the front-to-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 that is parallel to the front wall 21c and the rear wall 21d.

[0037] The top plate 22 is, for example, a flat plate made of metal. The top plate 22 has a planar shape that is the same as the contour 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 sealing rubber (not shown) sandwiched therebetween.

[0038] 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 sealing rubber (not shown) sandwiched therebetween.

[0039] 4, in the subtank 20, the fill tank FT is formed by the front wall 21c, separation wall 21w, left wall 21e, and right wall 21f of the main body 21, the top plate 22, and the bottom plate 23. The drain tank DT is formed by the rear wall 21d, separation wall 21w, left wall 21e, and right wall 21f of the main body 21, the top plate 22, and the bottom plate 23. The internal space INFT of the fill tank FT and the internal space INDT of the drain tank DT are each closed spaces and are separated from each other.

[0040] Two ink circulation ports IP20 are formed in the left wall 21e, side by side in the front-to-rear direction. The front ink circulation port IP20 communicates with the internal space INFT of the fill tank FT. The rear ink circulation port IP20 communicates with the internal space INDT of the drain tank DT.

[0041] Two air vent ports AP20 are formed in the top plate 22, side by side in the front-to-rear direction. The front air vent port AP20 is connected to the internal space INFT of the fill tank FT. The rear air vent port AP20 is connected to the internal space INDT of the drain tank DT. As shown in FIG. 10 , each of the two air vent ports AP20 is connected to the air pressure regulator 600 by a conduit AT via the air vent port AP10 on the rear side of the housing 10.

[0042] Ten ink circulation port sets S are provided on the underside 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 ports SP and ink discharge ports DP are aligned in the width direction.

[0043] A flow path (not shown) formed at the bottom inside the main body 21 connects the internal space INFT of the fill tank FT to the ink supply port SP of each ink flow port set S, and connects the internal space INDT of the drain tank DT to the ink discharge port DP of each ink flow port set S.

[0044] 6, the liquid level detection unit 30 includes a fill tank sensor 31 that detects the level of the ink stored in the fill tank FT, and a drain tank sensor 32 that detects the level of the ink stored in the drain tank DT. The fill tank sensor 31 and the drain tank sensor 32 are each an example of a "liquid level sensor."

[0045] 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.

[0046] The fill tank sensor 31 forms a pseudo-capacitor with the detection electrode 31E and a nearby grounded metal surface. The grounded metal surface may be, for example, a metal plate built into the fill tank sensor 31, or the top plate 22 or bottom plate 23 of the subtank 20. Similarly, the drain tank sensor 32 forms a pseudo-capacitor with the detection electrode 32E and a nearby grounded metal surface. The grounded metal surface may be, for example, a metal plate built into the drain tank sensor 32, or the top plate 22 or bottom plate 23 of the subtank 20.

[0047] The capacitance values ​​of the pseudo capacitors in the fill tank sensor 31 and the drain tank sensor 32 change depending on the position of the liquid level in the internal space INFT and the position of the liquid level in the internal space INDT. The fill tank sensor 31 and the drain tank sensor 32 each output the capacitance values ​​of the pseudo capacitors to the controller 700.

[0048] 7 , each of the ten head modules 40, which have the same configuration, includes, in order from top to bottom, a connection plate 41, a main body 42, and a head 43. The head module 40 further includes a wiring connection portion WC that extends in the vertical direction between the top of the connection plate 41 and the head 43.

[0049] The connection plate 41 is provided with an ink supply pipe connection portion ISC and an ink discharge pipe connection portion IDC.

[0050] 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 IDC.

[0051] 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.

[0052] 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 the top. As shown in FIG. 8, a flow path CH43 is formed inside the flow path unit 431.

[0053] The flow paths CH43 include eight ink circulation ports IP43, four manifold flow paths M1, M2, M3, and M4, and 48 individual flow paths iCH. Each of the four manifold flow paths M1 to M4 is a linear flow path, and communicates with the ink circulation port IP43 at both ends. Twelve individual flow paths iCH are connected to each of the four manifold flow paths M1 to M4.

[0054] A head filter FHD is located at each of the eight ink circulation ports IP43. The head filter FHD is configured to remove foreign matter and air bubbles that have become mixed in the ink.

[0055] 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 module 40, which is the nozzle surface 40n. A nozzle row L3 (FIG. 8) is formed on the nozzle surface 40n along the direction in which the manifold channels M1 to M4 extend.

[0056] 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 respectively positioned 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.

[0057] 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 Circuit) 441. The control board 442 is disposed inside the main body 42.

[0058] The wiring connection portion WC is in the form of a substrate. The upper end of the wiring connection portion WC protrudes above the connection plate 41. The wiring connection portion WC is connected to a relay substrate 50 (described later) via a flexible substrate (not shown). The lower end of the wiring connection portion WC is connected to the control substrate 442.

[0059] Each of the head modules 40 is fixed to the bottom 11b of the first housing 11 (FIG. 2). In this state, the nozzle surface 40n of each head module 40 is exposed facing downward from the housing 10. Furthermore, the nozzle row L3 of the nozzle surface 40n extends along the width direction of the head system 100. The ten head modules 40 are arranged in a staggered (zigzag) pattern along the width direction.

[0060] Each of the head modules 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.

[0061] 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 module 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 module 40.

[0062] Ink supplied from the subtank 20 to the ink supply pipe connection portion ISC via the ink supply pipe IST is branched in the main body portion 42 and flows into the ink circulation port IP43 of the head 43.

[0063] 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 manifold flow paths M1 to M4, and ink discharged from the manifold flow paths M1 to M4 flows to the ink discharge pipe connection portion IDC. The manifold flow paths M1 to M4 may all be configured so that ink flows in the same direction, or the manifold flow paths M1 and M3 may be configured so that the direction of ink flow in the manifold flow paths M2 and M4 is opposite to that of ink flow in the manifold flow paths M1 and M3.

[0064] <Relay Board 50> The relay board 50 mainly serves as a relay between the control board unit 60 (described later) and the control board 442 of the head module 40. The relay board 50 is connected to the wiring connection parts WC of each of the ten head modules 40 by a flexible board (not shown).

[0065] The relay board 50 is also connected to the power connector CN of the housing 10 by a wire (not shown), and distributes the power supplied from the power connector CN to the control board unit 60 and the like.

[0066] 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.

[0067] <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 module 40 via the relay board 50. The control board unit 60 is provided inside the second housing 12 of the housing 10 (FIG. 2).

[0068] Terminals (not shown) of the control board unit 60 protrude downward through openings (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 terminals to and from connectors (not shown) of the relay board 50 through openings (not shown) provided in the second region 11a2 of the top plate 11a of the first housing 11.

[0069] 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 will focus on one of the four.

[0070] As shown in FIG. 10, the HPM 500 mainly includes a pump P, a degassing unit DU, five flow paths (flow paths CH1 to CH5), five valves (valves Va to Ve), and an HPM filter FHPM.

[0071] Flow path CH1 connects the main tank 410 and the suction port PA of the pump P. Flow path CH2 connects the discharge port PB of the pump P and the fill tank FT via the ink circulation port IP10 on the front side of the casing 10 and the ink circulation port IP20 on the front side of the subtank 20. Flow path CH3 connects the flow path CH2 and the drain tank DT via the ink circulation port IP10 on the rear side of the casing 10 and the ink circulation port IP20 on the rear side of the subtank 20. Flow path CH4 connects the flow path CH1 and the flow path CH3. Flow path CH5 connects the flow path CH2 and the main tank 410.

[0072] The flow channel CH3 is connected to the flow channel CH2 at the branch J1 of the flow channel CH2. The flow channel CH4 is connected to the flow channel CH1 at the branch J2 of the flow channel CH1 and is connected to the flow channel CH3 at the branch J3 of the flow channel CH3. The flow channel CH5 is connected to the flow channel CH2 at the branch J4 of the flow channel CH2.

[0073] Valve Va is located on flow path CH1 between the main tank 410 and branch J2. Valve Vb is located on flow path CH2 between branch J1 and fill tank FT. Valve Vc is located on flow path CH3 between branch J1 and branch J3. Valve Vd is located on flow path CH4. Valve Ve is located on flow path CH5. Valves Va to Ve open and close flow paths CH1 to CH5, respectively.

[0074] The degassing unit DU is located on the flow path CH2 between the pump P and the branch J4. In this embodiment, the degassing unit DU is a known degassing module that removes gases such as air contained in the ink passing through the degassing unit DU.

[0075] The HPM filter FHPM is located in the flow path CH2 between the pump P and the degassing unit DU.

[0076] In the following description, the flow path from the main tank 410 to the fill tank FT via flow paths CH1 and CH2 is referred to as the supply flow path SCH (FIG. 11). When the HPM 500 forms the supply flow path SCH, valves Va and Vb are open, and valves Vc, Vd, and Ve are closed. The flow path from the drain tank DT to the fill tank FT via flow path CH3, branch J3, flow path CH4, branch J2, and flow path CH2 is referred to as the circulation flow path CCH (FIG. 12). When the HPM 500 forms the circulation flow path CCH, valves Vb and Vd are open, and valves Va, Vc, and Ve are closed. The flow path from the drain tank DT to the main tank 410 via flow path CH3, branch J3, flow path CH4, branch J2, flow path CH1, flow path CH2, branch J4, and flow path CH5 is referred to as the discharge flow path DCH (FIG. 13). When the HPM 500 forms the discharge flow path DCH, the valves Vd and Ve are open, and the valves Va, Vb, and Vc are closed. The region from branch J2 of the supply flow path SCH and the circulation flow path CCH to the fill tank FT is the overlapping portion of the supply flow path SCH and the circulation flow path CCH. The region from drain tank DT to branch J4 of the circulation flow path CCH and the discharge flow path DCH is the overlapping portion of the circulation flow path CCH and the discharge flow path DCH. The region from branch J2 of the supply flow path SCH and the discharge flow path DCH to branch J4 is the overlapping portion of the supply flow path SCH and the discharge flow path DCH. In this specification and the present invention, the term "overlap portion of a flow path and another flow path" refers to a portion where a flow path and another flow path are configured as a single flow path.

[0077] Additionally, the flow path from the fill tank FT through the ink supply pipe IST, the flow path CH43 of the head 43, and the ink discharge pipe IDT to the drain tank DT is called a head flow path HCH.

[0078] <Printing Method> The printer 1000 forms an image on the medium PM as follows, with the controller 700 controlling each part 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 drives the pump P with the valves Va and Vb of the HPM 500 open and the valves Vc to Ve closed, thereby sending ink from the main tank 410 to the fill tank FT via the supply flow path SCH.

[0080] The air pressure regulator 600 adjusts the air pressure in the air layer (the region where air exists above the ink surface) in the internal space INFT of the fill tank FT so that it is higher than the air pressure in the air layer in the internal space INDT of the drain tank DT. 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 CH43 of the head 43 via the ink supply pipe IST. In the head 43, ink that is not ejected from the nozzles 3 is sent to the drain tank DT via the ink discharge pipe IDT.

[0081] In parallel with the above-described 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 module 40 via the relay board 50 and a flexible board (not shown). The control board 442 of each head module 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 the appropriate timing.

[0082] The controller 700 alternately ejects ink and transports the medium PM using the transport rollers 301 and 302 to form an image on the medium PM according to the print data.

[0083] <Valve State Determination Process> A description will be given of the valve state determination process executed by the controller 700 in the printer 1000 of this embodiment. First, the significance of determining the state of the valve will be described.

[0084] Each of the valves Va to Ve provided in the HPM 500 of the above embodiment has the structure shown in FIG. 14(a) and FIG. 14(b), for example.

[0085] Specifically, each of valves Va to Ve is a solenoid valve, and mainly comprises a valve element BD that is moved by electromagnetic force and a rubber O-ring OR that is disposed around the opening OP of the flow path CH. In each of valves Va to Ve, when in the open state, the valve element BD is spaced apart from the opening OP, as shown in FIG. 14(a). On the other hand, in each of valves Va to Ve, when in the closed state, the valve element BD closes the opening OP, as shown in FIG. 14(b). This stops the flow of liquid through the flow path CH.

[0086] Here, in the valves Va to Ve, if the O-ring OR is in contact with the ink for a long period of time, the O-ring OR may swell due to factors such as material compatibility. In this case, the flow path resistance of the flow path CH increases, and even if the valves Va to Ve are open, there may be cases where not enough ink flows through the flow path CH. This type of swelling of the O-ring OR is likely to occur when the ink is UV ink.

[0087] Therefore, the controller 700 repeatedly executes the valve state determination process described below for each of the valves Va, Vb, Vd, and Ve at predetermined intervals. Here, "repeated execution" includes both a mode in which the valve state determination process is executed at regular intervals (periodic determination, regular determination) and a mode in which the interval between two consecutive determination processes is not constant (non-periodic determination, irregular determination). The periodic determination cycle and the interval between two consecutive non-periodic determination processes may be, for example, 24 hours, several hours, or several days. The controller 700 may execute the valve state determination process described below simultaneously with the printer 1000 printing on the medium PM, or may execute the process during a period when the printer 1000 is not printing on the medium PM.

[0088] Additionally, the controller 700 may execute the valve state determination process at any timing, such as when a predetermined process (such as a maintenance process) is completed or when an instruction to execute the state determination process is received from the user.

[0089] In this embodiment, valve Vc is a valve that is opened during initial setup of the printer 1000 and is generally closed, so the period during which the O-ring OR of valve Vc comes into contact with ink is shorter than the periods during which the O-rings OR of valves Va, Vb, Vd, and Ve come into contact with ink. Therefore, the controller 700 of this embodiment does not perform status determination for valve Vc. However, the controller 700 may also be configured to perform status determination for valve Vc.

[0090] The valve state determination process executed by the controller 700 includes a flow rate detection step S1, a valve abnormality determination step S2, a valve life prediction step S3, and a display step S4, as shown in the flowchart of Fig. 15. In the following description, valves Va to Ve will be collectively referred to as the "valve group."

[0091] <Flow Rate Detecting Step S1> As shown in the flowchart of FIG. 16, the flow rate detecting step S1 includes a supply flow rate detecting step S101, a circulation flow rate detecting step S102, and a discharge flow rate detecting step S103.

[0092] In a supply flow path flow rate detection process S101, the controller 700 detects the flow rate of ink flowing through the supply flow path SCH (hereinafter referred to as the "supply flow path flow rate QSCH"). In a circulation flow path flow rate detection process S102, the controller 700 detects the flow rate of ink flowing through the circulation flow path CCH (hereinafter referred to as the "circulation flow path flow rate QCCH"). In a discharge flow path flow rate detection process S103, the controller 700 detects the flow rate of ink flowing through the discharge flow path DCH (hereinafter referred to as the "discharge flow path flow rate QDCH").

[0093] Here, in each of the supply flow path flow rate detection process S101, the circulation flow path flow rate detection process S102, and the discharge flow path flow rate detection process S103, the controller 700 of this embodiment detects 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 the supply flow path flow rate QSCH, the circulation flow path flow rate QCCH, and the discharge flow path flow rate QDCH.

[0094] 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 31 over a predetermined period of time. 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 32 over a predetermined period of time. The length of the predetermined period can be set arbitrarily.

[0095] The reason why the gradient X of the detection value of the fill tank sensor 31 or the gradient Y of the detection value of the drain tank sensor 32 can be regarded as the flow rate of ink flowing through each flow path is as follows.

[0096] 17, the dashed line graph shows the time variation of the detected value (capacitance value) of the fill tank sensor 31, and the solid line graph shows the time variation of the detected value (capacitance value) of the drain tank sensor 32. The vertical axis of FIG. 17 represents the detected value (capacitance value), and the horizontal axis represents time.

[0097] Since the dielectric constant of ink is generally higher than that of air, as the amount of ink stored in the fill tank FT increases (i.e., as the liquid level rises), the capacitance value of the pseudo capacitor formed by the fill tank sensor 31 (i.e., the detection value of the fill tank sensor 31) increases. Conversely, as the amount of ink stored in the fill tank FT decreases (i.e., as the liquid level drops), the capacitance value of the pseudo capacitor formed 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.

[0098] Therefore, as shown in Figure 18(a), if the amount of ink stored in the fill tank FT during the period PP increases significantly, the increase in the detected value of the fill tank sensor 31 also increases, resulting in a larger slope X of the detected value of the fill tank sensor 31. If the increase in the amount of ink stored in the fill tank FT during the 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 the period PP is zero, the slope X also becomes zero. Furthermore, if the amount of ink stored in the fill tank FT decreases during the period PP, the slope X becomes a negative value. As shown in Figure 18(b), this relationship is similar for the slope Y of the detected value of the drain tank sensor 32.

[0099] In this way, when the outflow of ink from the fill tank FT is zero, the slope X of the detection value of the fill tank sensor 31 corresponds to the amount of ink flowing into the fill tank FT. Similarly, when the inflow of ink into the drain tank DT is zero, the slope Y of the detection value of the drain tank sensor 32 corresponds to the amount of ink flowing out from the drain tank DT. Therefore, the controller 700 can handle the values ​​of the slopes X and Y detected in the following manner, for example, as values ​​indicating the supply flow rate QSCH, the circulation flow rate QCCH, and the discharge flow rate QDCH.

[0100] In the supply flow path flow rate detection step S101, the controller 700 configures the supply flow path SCH by opening valves Va and Vb and closing valves Vc to Ve. Then, the controller 700 drives the pump P while stopping the supply of ink from the fill tank FT to the head module 40, and sends ink from the main tank 410 to the fill tank FT via the supply flow path SCH. In this state, the controller 700 detects the slope X of the detection value of the fill tank sensor 31 as the supply flow path flow rate QSCH. The controller 700 may also supply ink from the fill tank FT to the drain tank DT via the head flow path HCH, and detect the slope Y of the detection value of the drain tank sensor 32 as the supply flow path flow rate QSCH.

[0101] In the circulation channel flow rate detection step S102, the controller 700 configures the circulation channel CCH by opening valves Vb and Vd and closing valves Va, Vc, and Ve. The controller 700 then drives the pump P while stopping the supply of ink from the fill tank FT to the head module 40, and sends ink from the drain tank DT to the fill tank FT via the circulation channel CCH. In this state, the controller 700 detects the slope X of the detection value of the fill tank sensor 31 as the circulation channel flow rate QCCH. Alternatively, the controller 700 may stop the discharge of ink from the head module 40 to the drain tank DT and detect the slope Y of the detection value of the drain tank sensor 32 as the circulation channel flow rate QCCH.

[0102] In the discharge flow path flow rate detection step S103, the controller 700 configures the discharge flow path DCH by opening valves Vd and Ve and closing valves Va to Vc. The controller 700 then drives the pump P while stopping the discharge of ink from the head module 40 to the drain tank DT, and sends ink from the drain tank DT to the main tank 410 via the discharge flow path DCH. In this state, the controller 700 detects the slope Y of the detection value of the drain tank sensor 32 as the discharge flow path flow rate QDCH. The controller 700 may also supply ink from the fill tank FT to the drain tank DT via the head flow path HCH, and detect the slope X of the detection value of the fill tank sensor 31 as the discharge flow path flow rate QDCH.

[0103] The controller 700 may execute the supply flow path flow rate detection step S101 for a predetermined period (for example, several seconds to several minutes) and store the average value of the slope X or slope Y detected during the predetermined period in a storage unit (not shown). The storage unit may be a memory (e.g., a ROM) built into the controller 700, an external memory connected to the printer 1000, or a cloud-based memory. The stored average value is used as the latest value of the supply flow path flow rate QSCH in the valve abnormality determination step S2 and the valve life prediction step S3, which will be described later. The same applies to the slope X or slope Y detected in the circulation flow path flow rate detection step S102 and the slope X or slope Y detected in the discharge flow path flow rate detection step S103. Alternatively, the controller 700 may repeatedly execute multiple sets of the supply flow path flow rate detection step S101, the circulation flow path flow rate detection step S102, and the discharge flow path flow rate detection step S103, with each set consisting of the supply flow path flow rate detection step S101, the circulation flow path flow rate detection step S102, and the discharge flow path flow rate detection step S103, and store the average value of the detection values ​​over the multiple sets in a storage unit (not shown). In this case, the stored average values ​​are used as the latest value of the supply flow path flow rate QSCD, the latest value of the circulation flow path flow rate QCCH, and the latest value of the discharge flow path flow rate QDCH in the valve abnormality determination process S2 and the valve life prediction process S3 described below.

[0104] <Valve Abnormality Determination Process S2> In the valve abnormality determination process S2, the controller 700 determines whether or not there is an abnormality in each of the valves Va, Vb, Vd, and Ve based on the supply flow path flow rate QSCH, the circulation flow path flow rate QCCH, and the discharge flow path flow rate QDCH detected in the flow rate detection process S1.

[0105] The reason for determining whether or not there is an abnormality in the valves Va, Vb, Vd, and Ve based on the supply flow rate QSCH, the circulation flow rate QCCH, and the discharge flow rate QDCH is as follows.

[0106] If there is no abnormality in each valve, the flow rate in each flow path gradually decreases over time as shown in Fig. 19(a) The decrease in flow rate is caused, for example, by gradual clogging of the filter (HPM filter FHPM in this embodiment) disposed in the flow path.

[0107] On the other hand, if an abnormality occurs in one of the valves in the flow path and the flow rate at that valve decreases, the rate at which the flow rate in the flow path decreases (i.e., the slope of the graph) increases, as shown in Figure 19(b). Figure 19(b) shows that an abnormality occurs in the valve at time T1, and then the rate at which the flow rate decreases increases. In this case, the decrease in flow rate after time T1 is caused by the increasing clogging of the filter arranged in the flow path and the increasing swelling of the O-ring OR equipped in the valve.

[0108] Therefore, the controller 700 determines whether or not an abnormality has occurred for each of the valves Va, Vb, Vd, and Ve based on the presence or absence of an abnormality in the supply flow path flow rate QSCH, the circulation flow path flow rate QCCH, and the discharge flow path flow rate QDCH detected in the flow rate detection process S1 (more specifically, for example, whether or not there is a change in the rate of decrease).

[0109] The controller 700 executes the valve abnormality determination step S2 in accordance with the flowcharts shown in FIGS.

[0110] First, we will explain the flow rate abnormality determination step S25 (FIG. 22) used to determine whether or not there is an abnormality in the flow rate in the flow paths in steps S201, S202, S203, S206, S209, S210, and S213 of the flowcharts shown in Figures 20 and 21. In the following explanation of the flow rate abnormality determination step S25, the flow rate Q refers to any one of the supply flow path flow rate QSCH, the circulation flow path flow rate QCCH, and the discharge flow path flow rate QDCH, which are the targets of abnormality determination.

[0111] In step S251, the controller 700 calculates an approximate line AL passing through each data included in the time-series data SDQ based on the time-series data SDQ ( FIG. 23 ) of the flow rate Q at each past determination timing (i.e., each valve state determination process executed in the past). The calculation of the approximate line AL may use any linear approximation method, such as the least squares method. The linear approximation method is not limited to obtaining an approximate straight line, but may also obtain an approximate curve. Note that the controller 700 may exclude from the time-series data SDQ the value of the flow rate Q when it was determined in step S254 (described below) that the difference D was greater than the threshold value THD at a past determination timing.

[0112] In step S252, the controller 700 calculates a value on the calculated approximation line AL that corresponds to the current determination timing as the estimated value QES. That is, the estimated value QES is an estimate of the current flow rate Q that is estimated based on the tendency of changes in the flow rate Q at each past determination timing.

[0113] In step S253, the controller 700 calculates the difference D between the calculated estimated value QES and the latest value of the flow rate Q detected in the flow rate detection step S1, and in step S254, compares the calculated difference D with a threshold value THD.

[0114] If the controller 700 determines that the difference D is equal to or greater than the threshold value THD (S254: YES), the controller 700 adds "1" to the cumulative value A in step S255. The cumulative value A is a value indicating the number of consecutive determination timings at which it was determined that the difference D is equal to or greater than the threshold value THD (i.e., the number of consecutive determination timings at which a YES determination was made in step S254).

[0115] In step S256, the controller 700 compares the cumulative value A with the threshold value THA. If the cumulative value A is equal to or greater than the threshold value THA (S256: YES), the controller 700 determines that the flow rate Q is abnormal (S257).

[0116] If the controller 700 determines in step S254 that the difference D is smaller than the threshold value THD (S254: NO), the controller 700 returns the cumulative value A to "0" in step S258 and determines that the flow rate Q is normal in step S259. If the controller 700 determines in step S256 that the cumulative value A is smaller than the threshold value THA (S256: NO), the controller 700 determines in step S259 that the flow rate Q is normal.

[0117] In this way, in the flow rate abnormality determination step S25, the controller 700 determines that the flow rate Q in the flow path is abnormal if the difference between the latest value of the flow rate Q detected in the flow rate detection step S1 and the estimated value QES of the flow rate Q based on past detected values ​​is greater than the threshold value for more than a predetermined number of consecutive determination timings. This makes it possible to suppress the influence of variations in the detected value of the flow rate Q due to errors, etc., and more accurately determine whether or not the flow rate Q is abnormal.

[0118] Next, the flowcharts shown in FIGS. 20 and 21 will be described.

[0119] In step S201, the controller 700 determines whether or not there is an abnormality in the discharge flow path flow rate QDCH in accordance with the flow rate abnormality determination process S25. If the controller 700 determines in step S201 that there is an abnormality in the discharge flow path flow rate QDCH (S201: YES), in step S202, the controller 700 determines whether or not there is an abnormality in the circulation flow path flow rate QCCH in accordance with the flow rate abnormality determination process S25. If the controller 700 determines in step S202 that there is an abnormality in the circulation flow path flow rate QCCH (S202: YES), in step S203, the controller 700 determines whether or not there is an abnormality in the supply flow path flow rate QSCH in accordance with the flow rate abnormality determination process S25.

[0120] If the controller 700 determines in step S203 that there is an abnormality in the supply flow path flow rate QSCH (S203: YES), the controller 700 determines in step S204 that the valve group is in the first state. When the valve group is in the first state, the valves Va, Vb, Vd, and Ve are in one of the following states: (1) Valves Va and Vd are abnormal, and the other valves are normal. (2) Valves Vb and Vd are abnormal, and the other valves are normal. (3) Valves Vb and Ve are abnormal, and the other valves are normal. (4) Valves Va, Vb, and Vd are abnormal, and the other valves are normal. (5) Valves Va, Vb, and Ve are abnormal, and the other valves are normal. (6) Valves Va, Vd, and Ve are abnormal, and the other valves are normal. (7) Valves Vb, Vd, and Ve are abnormal, and the other valves are normal. (8) Valves Va, Vb, Vd, and Ve are all abnormal.

[0121] If the controller 700 determines in step S203 that the supply flow rate QSCH is normal (S203: NO), it determines in step S205 that the valve group is in the second state. When the valve group is in the second state, the valves Va, Vb, Vd, and Ve are in one of the following states: (1) Valve Vd is abnormal, and the other valves are normal; or (2) Valves Vd and Ve are abnormal, and the other valves are normal.

[0122] If the controller 700 determines in step S202 that the circulation flow rate QCCH is normal (S202: NO), it determines in step S206 whether or not there is an abnormality in the supply flow rate QSCH in accordance with the flow rate determination step S25.

[0123] If the controller 700 determines in step S206 that there is an abnormality in the supply flow path flow rate QSCH (S206: YES), it determines in step S207 that the valve group is in the third state. When the valve group is in the third state, valves Va, Vb, Vd, and Ve are abnormal, and the other valves are normal.

[0124] If the controller 700 determines in step S206 that the supply flow path flow rate QSCH is normal (S206: NO), the controller 700 determines in step S205 that the valve group is in the fourth state. When the valve group is in the fourth state, valves Va, Vb, Vd, and Ve are abnormal, and the other valves are normal.

[0125] If the controller 700 determines in step S201 that the discharge flow rate QDCH is normal (S201: NO), it determines in step S209 whether or not there is an abnormality in the circulation flow rate QCCH in accordance with the flow rate determination step S25.

[0126] If the controller 700 determines that there is an abnormality in the circulation flow path flow rate QCCH (S209: YES), in step S210, it determines whether there is an abnormality in the supply flow path flow rate QSCH according to the flow rate determination process S25. If the controller 700 determines that there is an abnormality in the supply flow path flow rate (S210: YES), it determines in step S211 that the valve group is in the fifth state. When the valve group is in the fifth state, valves Va, Vb, Vd, and Ve are in one of the following states: (1) Valve Vb is abnormal, and the other valves are normal; (2) Valves Va and Vb are abnormal, and the other valves are normal.

[0127] If the controller 700 determines in step S210 that the supply flow path flow rate QSCH is normal (S210: NO), it determines in step S212 that the valve group is in the sixth state. When the valve group is in the sixth state, the states of valves Va, Vb, Vd, and Ve are unknown. In other words, determining that the valve group is in the sixth state is an error determination. In the sixth state, there is no abnormality in the supply flow path flow rate QSCH, but there is an abnormality in the circulation flow path flow rate QCCH, so it is estimated that there is an abnormality in valve Vd. On the other hand, there is no abnormality in the discharge flow path flow rate QDCH, so it is estimated that there is no abnormality in valve Vd. In this way, since mutually contradictory estimates are valid in the sixth state, it is believed that some kind of error has occurred.

[0128] If the controller 700 determines in step S209 that the circulation flow path flow rate QCCH is normal (S209: NO), then in step S213 it determines whether or not there is an abnormality in the supply flow path flow rate QSCH according to the flow rate abnormality determination process S25. If the controller 700 determines that there is an abnormality in the supply flow path flow rate QSCH (S213: YES), then in step S214 it determines that the valve group is in the seventh state. When the valve group is in the seventh state, valve Va, valve Vb, valve Vd, and valve Ve, valve Va is abnormal and the other valves are normal.

[0129] If the controller 700 determines in step S213 that the supply flow path flow rate QSCH is normal (S213: NO), the controller 700 determines in step S215 that the valve group is in state 8. When the valve group is in state 8, the valves Va, Vb, Vd, and Ve are all normal.

[0130] <Valve life prediction process S3> In the valve life prediction process S3, the controller 700 predicts the life of each of the valves Va, Vb, Vd, and Ve based on the supply flow path flow rate QSCH, the circulation flow path flow rate QCCH, and the discharge flow path flow rate QDCH detected in the flow rate detection process S1.

[0131] The controller 700 executes the valve life prediction step S3 according to the flowchart shown in Fig. 24. In step S301, the controller 700 predicts the life of the valve Va based on the supply flow path flow rate QSCH. In step S302, the controller 700 predicts the life of the valve Vb based on the supply flow path flow rate QSCH or the circulation flow path flow rate QCCH. In step S303, the controller 700 predicts the life of the valve Vd based on the circulation flow path flow rate QCCH or the exhaust flow path flow rate QDCH. In step S304, the controller 700 predicts the life of the valve Ve based on the exhaust flow path flow rate QDCH.

[0132] In each of steps S301 to S304, the controller 700 predicts the lifespan of the valve in accordance with the lifespan prediction process S35 shown in Fig. 25. In the following description of the lifespan prediction process S35, the flow rate Q refers to any one of the supply flow path flow rate QSCH, the circulation flow path flow rate QCCH, and the discharge flow path flow rate QDCH used in the lifespan prediction.

[0133] In step S351, the controller 700 calculates, as an estimated value QES, a value on an approximate line AL1 calculated based on time-series data SDQ1 ( FIG. 26( a) ) of the flow rate Q at each past prediction timing, which corresponds to the current prediction timing. As the approximate line AL1, the approximate line AL2 calculated in step S356 (described later) or the approximate line AL1 calculated in step S359 (described later) at the immediately previous prediction timing in the life prediction process S35 can be used. Note that the approximate line AL1 is calculated using any linear approximation method, such as the least squares method. The linear approximation method is not limited to one that finds an approximate straight line, but may also be one that finds an approximate curve.

[0134] In step S352, the controller 700 calculates the difference DD between the calculated estimated value QES and the latest value of the flow rate Q detected in the flow rate detection step S1, and in step S353, compares the calculated difference DD with a threshold value THDD.

[0135] If the controller 700 determines in step S353 that the difference DD is equal to or greater than the threshold value THDD (S353: YES), it adds "1" to the cumulative value AA in step S354. The cumulative value AA is a value indicating the number of consecutive predicted timings at which it was determined that the difference DD was equal to or greater than the threshold value THDD (i.e., the number of consecutive predicted timings at which it was determined that YES was returned in step S353).

[0136] In step S355, the controller 700 compares the cumulative value AA with the threshold value THAA. If the controller 700 determines that the cumulative value AA is equal to or greater than the threshold value THAA (S355: YES), the controller 700 recalculates the approximation line in step S356.

[0137] Specifically, in step S356, the controller 700 calculates an approximate line AL2 passing through each data included in the time-series data SDQ2 based on the time-series data SDQ2 ( FIG. 26( b) ) of the flow rate Q at the determination timing of the cumulative value AA immediately prior to determining that the difference DD is equal to or greater than the threshold value THDD. In other words, the controller 700 calculates a new approximate line AL2 using only the value of the flow rate Q after the latest value of the flow rate Q begins to deviate from the estimated value of the flow rate Q based on past data. The calculation of the approximate line AL2 may use any linear approximation method, such as the least squares method. The linear approximation method is not limited to obtaining an approximate straight line, but may also be one that obtains an approximate curve.

[0138] In step S357, the controller 700 performs a life prediction using the newly calculated approximation line AL2. Specifically, the process is as follows.

[0139] 27, if the current operating time is operating time OH1 and the operating time at the point when the flow rate Q has fallen to the lower limit MIN, which is the minimum value required for normal operation of the printer 1000, is operating time OH2, the period from operating time OH1 to operating time OH2 corresponds to the life LTV of the valve V. The controller 700 calculates the life LTV of the valve V as the difference between the current operating time OH1 and the operating time OH2 corresponding to point X, indicated by the approximation line AL2, where the flow rate Q reaches the lower limit MIN.

[0140] If the controller 700 determines in step S353 that the difference DD is smaller than the threshold value THDD (S353: NO), the controller 700 resets the cumulative value AA to "0" in step S358 and proceeds to step S359. If the controller 700 determines in step S355 that the cumulative value AA is smaller than the threshold value THAA (S355: NO), the controller 700 proceeds to step S359. In step S359, the controller 700 includes the latest value of the flow rate Q in the time-series data SDQ1 and recalculates the approximate line AL1. That is, the previous approximate line AL1 is updated. Thereafter, in step S360, the controller 700 calculates the lifetime LTV of the valve V using the updated approximate line AL1. The controller 700 calculates the lifetime LTV in the same manner as in step S357.

[0141] Thus, in the life prediction process S3, the controller 700 predicts the valve life based on the flow rate reduction trend based on past data. The life LTV value calculated in step S360 of the life prediction process S35 is a value calculated before swelling of the valve's O-ring OR occurs, and can essentially be considered a predicted life value of the HPM filter FHPM. However, even if the life LTV value calculated in step S360 is substituted for the predicted value of the valve life, there is no problem because it is considered to be a value shorter than the valve's actual life. On the other hand, the life LTV value calculated in step S357 of the life prediction process S35 reflects the reduction in flow rate due to swelling of the valve's O-ring OR and can be considered a more accurate prediction.

[0142] <Display Step S4> In the display step S4, the controller 700 displays the determination result of the valve abnormality determination step S2 and the prediction result of the valve life prediction step S3 on the display unit 900. Specifically, for example, the controller 700 displays, based on the result of the valve abnormality determination step S2, which of the valves Va, Vb, Vd, and Ve has been determined to have an abnormality by using text information, an icon, or the like on the display unit 900. The controller 700 also displays, on the display unit 900, the value of the life LTV calculated in the valve life prediction step S3 for each of the valves Va, Vb, Vd, and Ve.

[0143] The advantageous effects of the printer 1000 and the valve state determination method of this embodiment are summarized below.

[0144] In the printer 1000 and valve status determination method of this embodiment, the supply flow path flow rate QSCH, the circulation flow path flow rate QCCH, and the discharge flow path flow rate QDCH are detected using a fill tank sensor 31 for detecting the amount of fluid in the fill tank FT and a drain tank sensor 32 for detecting the amount of fluid in the drain tank DT. The detected supply flow path flow rate QSCH, circulation flow path flow rate QCCH, and discharge flow path flow rate QDCH are then used to determine the status of valves Va, Vb, Vd, and Ve (i.e., to determine abnormalities and predict lifespans). Therefore, there is no need to provide separate sensors for determining the status of each valve, and a configuration for determining the status of the valves can be implemented at low cost.

[0145] In the printer 1000 and valve state determination method of this embodiment, in the flow rate abnormality determination step S25, if the difference D between the estimated value QES of the flow rate Q and the latest value of the flow rate Q is continuously equal to or greater than a threshold value for a predetermined number of determination timings, it is determined that the flow rate Q is abnormal. Therefore, the influence of measurement error of the flow rate Q is suppressed, and the presence or absence of an abnormality in the flow rate Q can be determined more accurately.

[0146] [Modifications] The following modifications can also be used in the above embodiment.

[0147] <Modification of Flow Rate Detection> In the above embodiment, the liquid levels in the fill tank FT and the drain tank DT are detected by the fill tank sensor 31 and the drain tank sensor 32, which are capacitance-type liquid level sensors. The supply flow rate QSCH, the circulation flow rate QCCH, and the discharge flow rate QDCH are also detected using the fill tank sensor 31 and the drain tank sensor 32. However, the present invention is not limited to this.

[0148] As an example, the fill tank sensor 31 and the drain tank sensor 32 are not limited to capacitance-type liquid level sensors. The fill tank sensor 31 and the drain tank sensor 32 may be any liquid level sensor (e.g., float-type, optical-type, radio-wave-type, etc.) capable of detecting 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 sensors, but may be any liquid level sensor capable of detecting the liquid level in the fill tank FT and the drain tank DT, respectively. The liquid level sensor may be any liquid level sensor, for example, configured to detect the liquid level 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. The liquid level sensor is one aspect of a liquid level sensor. Regardless of the type of liquid level sensor, the supply flow rate QSCH, the circulation flow rate QCCH, and the discharge flow rate QDCH can be detected, as in the above embodiment.

[0149] As another example, a flow sensor that detects at least one of the supply flow rate QSCH, circulation flow rate QCCH, and discharge flow rate QDCH may be disposed in at least one of the supply flow rate SCH, circulation flow rate CCH, and discharge flow rate DCH.

[0150] Specifically, for example, a flow sensor for detecting the supply flow path flow rate QSCH may be disposed between the main tank 410 and the valve Va of the supply flow path SCH, a flow sensor for detecting the circulation flow path flow rate QCCH may be disposed between the valve Vb of the circulation flow path CCH and the fill tank FT, and a flow sensor for detecting the discharge flow path flow rate QDCH may be disposed between the valve Ve of the discharge flow path DCH and the main tank 410. Alternatively, flow sensors for detecting the supply flow path flow rate QSCH and the circulation flow path flow rate QCCH may be disposed between the valve Vb and the fill tank FT, which is an overlapping portion of the supply flow path SCH and the circulation flow path CCH, and a flow sensor for detecting the discharge flow path flow rate QDCH may be disposed between the valve Ve of the discharge flow path DCH and the main tank 410. Alternatively, a single flow sensor disposed in an overlapping portion of the supply flow path SCH, the circulation flow path CCH, and the discharge flow path DCH (e.g., the region between the pump P and the degassing unit DU) may detect all of the supply flow path flow rate QSCH, the circulation flow path flow rate QCCH, and the discharge flow path flow rate QDCH. Alternatively, one or more flow rate sensors may be arbitrarily arranged to detect at least one of the supply flow rate QSCH, the circulation flow rate QCCH, and the discharge flow rate QDCH.

[0151] In this way, even if a flow sensor is used in addition to the liquid volume sensors that detect the liquid volume in the fill tank FT and the drain tank DT, costs are reduced compared to an embodiment in which two pressure sensors are used to determine the state of one valve (for example, an embodiment in which a pressure sensor is placed upstream and downstream of the valve being determined). Note that the type of flow sensor is arbitrary. Each flow sensor is an example of a "first flow detector" and / or a "second flow detector."

[0152] <Modification of Valve Abnormality Determination> In the above embodiment, in the valve abnormality determination step S2, the controller 700 determines whether or not there is an abnormality in the discharge flow rate QDCH, the circulation flow rate QCCH, and the supply flow rate QSCH in this order, but this is not limited to this. The order in which the abnormality determination for the three flow rates is performed is arbitrary, and regardless of the order, the controller 700 can determine which of the first to eighth states exists depending on the abnormal / normal combination of the three flow rates.

[0153] In the valve abnormality determination process S2 in the above embodiment, steps S204, S205, and S211 are processes for determining whether the valve state is state 1, state 2, or state 5, respectively, or in other words, for determining whether one or more valves have an abnormality. The controller 700 may execute the following process after these processes.

[0154] As an example, the controller 700 may compare the rate of decrease in flow rate of the flow paths in which multiple (e.g., two) valves determined to possibly have an abnormality are located with a threshold value after steps S204, S205, and S211. Then, if the rate of decrease in flow rate is equal to or greater than the threshold value, it may be determined that multiple (e.g., two) valves have an abnormality, and if the amount of decrease in flow rate is smaller than the threshold value, it may be determined that only one valve has an abnormality.

[0155] Specifically, for example, after determining in step S205 that an abnormality has occurred in valve Vd or that an abnormality has occurred in valves Vd and Ve, the controller 700 compares the rate of decrease in the discharge flow path flow rate QDCH (the slope of the approximation line AL calculated in step S251) with a threshold value. If the rate of decrease is equal to or greater than the threshold value, the controller 700 determines that an abnormality has occurred in valves Vd and Ve, and if the rate of decrease is smaller than the threshold value, the controller 700 determines that an abnormality has occurred in only valve Vd. The same applies to the steps performed after step S204 and step S211. Note that in the steps performed after step S204, multiple threshold values ​​may be used to determine whether two, three, or four valves are abnormal.

[0156] As another example, the controller 700 may compare the amount of flow rate reduction in the flow paths in which multiple (e.g., two) valves determined to possibly have an abnormality are located with a threshold value after steps S204, S205, and S211. If the amount of flow rate reduction is equal to or greater than the threshold value, it may be determined that multiple (e.g., two) valves have an abnormality, and if the amount of flow rate reduction is smaller than the threshold value, it may be determined that only one valve has an abnormality.

[0157] Specifically, for example, after determining in step S205 that valve Vd is abnormal or that both valves Vd and Ve are abnormal, the controller 700 compares the decrease in the discharge flow path flow rate QDCH (which may be the difference D calculated in the flow rate abnormality determination step S25 or the decrease from the value at the previous determination timing) with a threshold value (which may be a value greater than the threshold value THD used in the flow rate abnormality determination step S25). If the decrease is equal to or greater than the threshold value, the controller 700 determines that valves Vd and Ve are abnormal, and if the decrease is smaller than the threshold value, the controller 700 determines that only valve Vd is abnormal. The same applies to steps performed after step S204 and step S211. Note that in the steps performed after step S204, multiple threshold values ​​may be used to determine whether two, three, or four valves are abnormal.

[0158] As another example, the controller 700 may compare the amount of flow rate reduction in the flow paths in which two of the valves determined to possibly have an abnormality are located with the amount of flow rate reduction in the flow path in which one of the valves determined to possibly have an abnormality is located after steps S204, S205, and S211. Then, the controller 700 may determine that both valves are abnormal if the difference between the amount of flow rate reduction in the flow paths in which two of the valves determined to possibly have an abnormality are located and the amount of flow rate reduction in the flow path in which one of the valves determined to possibly have an abnormality is located is equal to or greater than a threshold value, and may determine that one valve is abnormal if the difference is smaller than the threshold value.

[0159] Specifically, for example, after determining in step S205 that an abnormality has occurred in valve Vd or that an abnormality has occurred in valves Vd and Ve, the controller 700 compares the decrease in the discharge flow path flow rate QDCH of the discharge flow path DCH in which both valves Vd and Ve are located (which may be the difference D calculated in the flow rate abnormality determination step S25, or may be the decrease from the value at the previous determination timing) with the decrease in the circulation flow path flow rate QCCH of the circulation flow path CCH in which only valve Vd is located. Then, the controller 700 compares the difference between the decrease in the discharge flow path flow rate QDCH and the decrease in the circulation flow path flow rate QCCH with a threshold value. If the difference is greater than or equal to the threshold value, it is determined that an abnormality has occurred in valves Vd and Ve. If the difference is smaller than the threshold value, it is determined that an abnormality has occurred in only valve Vd. The same applies to steps performed after steps S204 and S211.

[0160] In the above embodiment, in the flow rate abnormality determination step S25 of the valve abnormality determination step S2, the controller 700 determines that the flow rate Q is abnormal (S257) if the cumulative value A is equal to or greater than the threshold value THA (S256: YES). However, this is not limited thereto. The controller 700 may also determine that the flow rate Q is abnormal if it is determined in step S254 that the difference D is equal to or greater than the threshold value (S254: YES).

[0161] In the above embodiment, step S258 may be omitted in the flow rate abnormality determination step S25 of the valve abnormality determination step S2. That is, if it is determined that the difference D is smaller than the threshold value THD (S254: YES), the cumulative value A does not need to be reset to "0".

[0162] <Modification of Valve Life Prediction Process> In the above embodiment, in the valve life prediction process S3, if the controller 700 determines in step S355 that the cumulative value AA is equal to or greater than the threshold value THAA (S355: YES), the controller 700 recalculates the approximation line in step S356. This recalculation of the approximation line is performed using only the value of the flow rate Q after the latest value of the flow rate Q begins to deviate from the estimated value of the flow rate Q based on past data. However, the data used to recalculate the approximation line in step S356 is not limited to this. The controller 700 can recalculate the approximation line in any manner that reflects the gradient of the change in the flow rate Q over time at multiple determination times when it is determined that the difference DD is greater than the threshold value THDD (step S353: YES).

[0163] Specifically, for example, the controller 700 may include the flow rate Q0 (FIG. 26(b) ; the flow rate at the bending point between the approximation lines AL1 and AL2) at the determination timing immediately before the first determination timing at which it was determined that the difference DD was greater than the threshold value THDD in the time-series data SDQ2 used to recalculate the approximation line. Alternatively, the controller 700 may include the flow rate Q at a determination timing earlier than the determination timing at which the flow rate Q0 was detected in the time-series data SDQ2 used to recalculate the approximation line. Even in such a case, if the slope of the recalculated approximation line is greater than the slope of the approximation line before recalculation, it can be said that the influence of a valve abnormality is reflected. Therefore, it can be said that the recalculated approximation line reflects the slope of the change in the flow rate Q over time at multiple determination timings at which it was determined that the difference DD was greater than the threshold value THDD.

[0164] In the valve life prediction step S3 of the above embodiment, the controller 700 may recalculate the approximation line in step S356 and then calculate the difference between the slope of the approximation line before recalculation and the slope of the recalculated approximation line. If the calculated difference is equal to or greater than a threshold (i.e., if the change in slope is equal to or greater than the threshold), the controller 700 may determine that the recalculated approximation line reflects the slope of the change in the flow rate Q over time at multiple determination times at which it was determined that the difference DD was greater than the threshold THDD, and may perform life prediction using the recalculated approximation line (step S357). On the other hand, if the calculated difference is smaller than the threshold (i.e., if the change in slope is smaller than the threshold), the controller 700 may determine that large foreign matter has clogged the HPM filter FHPM. This is because, if the slope of the approximation line recalculated based on the flow rate Q at multiple determination timings at which it was determined that the difference DD was greater than the threshold value THDD is similar to the slope of the approximation line before recalculation, there is a possibility that a stepwise decrease in the flow rate Q has occurred due to clogging of the filter, such as the change in flow rate at time T2 in Fig. 28. Note that the controller 700 may then execute step S357.

[0165] In the above embodiment, step S358 may be omitted in the life prediction step S35. That is, when it is determined that the difference DD is smaller than the threshold value THDD (S353: YES), the cumulative value AA does not need to be reset to "0".

[0166] In this specification and the present invention, the slope of the change in flow rate over time means the slope of an approximate straight line when the change in flow rate over time is represented by an approximate straight line. Also, when the change in flow rate over time is represented by an approximate curve, the slope of the change in flow rate over time may be the average slope of the tangents to the approximate curve, or the slope of the tangent at any one point (for example, the determination time point) on the approximate curve.

[0167] <Other Modifications> In the above embodiment, the controller 700 targets the valves Va, Vb, Vd, and Ve for state determination, but this is not limited to this. As an example, the controller 700 may target only the valves Va, Vb, and Vd for state determination. In this case, the valves Va, Vb, and Vd correspond to the "third valve," the "first valve," and the "second valve," respectively, and the supply flow path SCH and the circulation flow path CCH correspond to the "second flow path" and the "first flow path," respectively. In this case, if the valve Ve is further included in the targets for state determination, the valve Ve corresponds to the "fourth valve," and the discharge flow path DCH corresponds to the "third flow path."

[0168] As another example, the controller 700 may only target the valves Vb, Vd, and Ve for state determination. In this case, the valves Vb, Vd, and Ve correspond to the "second valve," the "first valve," and the "third valve," respectively, and the circulation flow path CCH and the discharge flow path DCH correspond to the "first flow path" and the "second flow path," respectively. In this case, if the valve Va is further included in the state determination targets, the valve Va corresponds to the "fourth valve," and the supply flow path SCH corresponds to the "third flow path."

[0169] In the above embodiment and modified examples, the controller 700 may select only one or more of the valves Va to Ve as the object of judgment (object of abnormality judgment and / or object of life prediction).

[0170] In addition, when the valve state determination by the controller 700 is related to only two flow paths, the HPM 500 may be configured to configure only those two flow paths.

[0171] In the above embodiment, the controller 700 predicts the lifespan of the valves Va, Vb, Vd, and Ve in the valve lifespan prediction step S3, but this is not limiting. The controller 700 may predict the lifespan of only those valves Va, Vb, Vd, and Ve that have been determined to have an abnormality in the immediately preceding valve abnormality determination step S2.

[0172] In the above embodiment, the controller 700 executes both the valve abnormality determination step S2 and the valve life prediction step S3 in the valve state determination process, but this is not limited to this. The controller 700 may be configured to execute at least one of the valve abnormality determination step S2 and the valve life prediction step S3 in the valve state determination process.

[0173] In the above embodiment and modified examples, the controller 700 included in the printer 1000 executes the valve state determination process, but this is not limiting. For example, a controller implemented externally to the printer 1000, such as on the cloud or in an external device (e.g., a PC), may execute the valve state determination process via communication with the printer 1000. In this case, a liquid ejection system is formed by the printer 1000 and the controller implemented externally to the printer 1000. Furthermore, information display and notification in the valve state determination process may be performed via an external device (e.g., a PC) rather than the display unit 900.

[0174] The above has described 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.

[0175] In the above embodiment and modified examples, valves Va to Ve are solenoid valves, and the abnormality of valves Va to Ve is mainly explained as a decrease in flow rate due to swelling of the O-ring OR. However, valves Va to Ve may be any valve other than solenoid valves, and the abnormality of valves Va to Ve may be any flow rate abnormality. For example, a valve malfunction may occur due to foreign matter getting caught in the valve drive unit or deterioration of a valve component (such as a spring), resulting in a flow rate abnormality. Alternatively, in the case of a valve that performs its opening and closing function by the elasticity (sealing property) of rubber, the rubber may swell due to material compatibility when it comes into contact with ink, resulting in a flow rate abnormality.

[0176] The embodiments described in this specification are illustrative in all respects and should not be considered 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 simultaneously print 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 modified example 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.

[0177] 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 that can be conceived within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0178] (Additional Notes) 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.

[0179] a first flow path that supplies the liquid to the head and / or discharges the liquid from the head; a second flow path that supplies the liquid to the head and / or discharges the liquid from the head, the second flow path partially overlapping with the first flow path; a first valve that opens and closes the first flow path and the second flow path at an overlapping portion between the first flow path and the second flow path; a second valve that opens and closes the first flow path at a position different from the overlapping portion; a third valve that opens and closes the second flow path at a position different from the overlapping portion; a first flow rate detector that detects a flow rate of the liquid flowing through the first flow path; a second flow rate detector that detects a flow rate of the liquid flowing through the second flow path; and a controller that determines whether or not there is an abnormality and / or predicts a lifespan of at least one of the first valve, the second valve, and the third valve based on a detection value of the first flow rate detector and / or a detection value of the second flow rate detector.

[0180] (Item 2) The liquid ejection system according to Item 1, wherein the first flow rate detector also serves as the second flow rate detector.

[0181] (Item 3) A liquid ejection system as described in item 1 or 2, further comprising a tank for storing the liquid supplied to the head and / or the liquid discharged from the head, wherein the first flow path and the second flow path are connected to the tank, and at least one of the first flow rate detector and the second flow rate detector is a liquid volume sensor for detecting the amount of the liquid stored in the tank.

[0182] (Item 4) A liquid ejection system described in any one of items 1 to 3, wherein the controller determines whether or not there is an abnormality in at least one of the first valve, the second valve, and the third valve based on a determination of whether or not the detection value of the first flow rate detector is an abnormal value and a determination of whether or not the detection value of the second flow rate detector is an abnormal value.

[0183] (Item 5) The liquid ejection system described in Item 4, wherein the controller determines that an abnormality has occurred in the second valve when it determines that the detection value of the first flow rate detector is an abnormal value and the detection value of the second flow rate detector is a normal value, and determines that an abnormality has occurred in the third valve when it determines that the detection value of the first flow rate detector is a normal value and the detection value of the second flow rate detector is an abnormal value.

[0184] (Item 6) The liquid ejection system described in Item 4 or 5, wherein the controller calculates the difference between an estimated value calculated based on past values ​​of the detection value of the first flow detector and the latest value of the detection value of the first flow detector at multiple different times, and determines that the detection value of the first flow detector is an abnormal value if the calculated difference is greater than a threshold value over multiple times greater than a predetermined number of times.

[0185] (Item 7) A liquid ejection system described in any one of items 1 to 6, wherein the controller predicts the lifespan of the first valve and / or the second valve based on the slope of the change over time in the detection value of the first flow detector, and / or predicts the lifespan of the first valve and / or the third valve based on the slope of the change over time in the detection value of the second flow detector.

[0186] (Item 8) A liquid ejection system described in any one of items 1 to 7, wherein the controller calculates the difference between an estimated value calculated based on past values ​​of the detection value of the first flow detector and the latest value of the detection value of the first flow detector at multiple different times, and if the calculated difference is greater than a threshold value over a predetermined number of multiple times, predicts the lifespan of the first valve and / or the second valve based on the slope of the change over time in the detection value of the first flow detector corresponding to the multiple times.

[0187] (Item 9) The liquid ejection system according to any one of Items 1 to 8, wherein the controller performs a life prediction for a valve determined to have an abnormality among the first valve, the second valve, and the third valve.

[0188] (Item 10) A liquid ejection system described in any one of items 1 to 9, further comprising: a third flow path that supplies the liquid to the head and / or discharges the liquid from the head, the third flow path partially overlapping with the first flow path; a fourth valve that opens and closes the third flow path; and a third flow rate detector that detects the flow rate of the liquid flowing through the third flow path, wherein the second valve opens and closes the first flow path and the third flow path at an overlapping portion between the first flow path and the third flow path, and the fourth valve opens and closes the third flow path at a position different from the overlapping portion between the first flow path and the third flow path, and the controller determines whether or not there is an abnormality and / or predicts the lifespan of at least one of the first valve, the second valve, the third valve, and the fourth valve based on a detection value of the first flow rate detector and / or a detection value of the second flow rate detector and / or a detection value of the third flow rate detector.

[0189] (Item 11) The liquid ejection system according to Item 10, wherein the first flow rate detector also serves as the third flow rate detector.

[0190] a first flow path that supplies the liquid to the head and / or discharges the liquid from the head; a second flow path that supplies the liquid to the head and / or discharges the liquid from the head, the second flow path partially overlapping with the first flow path; a first valve that opens and closes the first flow path and the second flow path at an overlapping portion between the first flow path and the second flow path; a second valve that opens and closes the first flow path at a position different from the overlapping portion; a third valve that opens and closes the second flow path at a position different from the overlapping portion; a first flow rate detector that detects a flow rate of the liquid flowing through the first flow path; and a second flow rate detector that detects the flow rate of the liquid flowing through the second flow path, and the valve state determination method determines whether or not there is an abnormality and / or predicts a lifespan of at least one of the first valve, the second valve, and the third valve based on a detection value of the first flow rate detector and / or a detection value of the second flow rate detector.

[0191] 20 Subtank 30 Liquid level detection unit 31 Fill tank sensor 32 Drain tank sensor 40 Head module 43 Head 100 Head system 400 Ink tank 500 HPM 700 Controller 1000 Printer DT Drain tank Va, Vb, Vc, Vd, Ve Valves FT Fill tank P Pump

Claims

a first flow path that supplies the liquid to the head and / or discharges the liquid from the head; a second flow path that supplies the liquid to the head and / or discharges the liquid from the head, the second flow path partially overlapping with the first flow path; a first valve that opens and closes the first flow path and the second flow path at an overlapping portion between the first flow path and the second flow path; a second valve that opens and closes the first flow path at a position different from the overlapping portion; a third valve that opens and closes the second flow path at a position different from the overlapping portion; a first flow rate detector that detects the flow rate of the liquid flowing through the first flow path; a second flow rate detector that detects the flow rate of the liquid flowing through the second flow path; and a controller that determines whether or not there is an abnormality and / or predicts the lifespan of at least one of the first valve, the second valve, and the third valve based on the detection value of the first flow rate detector and / or the detection value of the second flow rate detector.

2. The liquid ejection system according to claim 1, wherein the first flow rate detector also serves as the second flow rate detector.

3. A liquid ejection system as described in claim 1 or 2, further comprising a tank for storing the liquid supplied to the head and / or the liquid discharged from the head, wherein the first flow path and the second flow path are connected to the tank, and at least one of the first flow rate detector and the second flow rate detector is a liquid volume sensor for detecting the amount of the liquid stored in the tank.

4. A liquid ejection system as described in claim 1 or 2, wherein the controller determines whether or not there is an abnormality in at least one of the first valve, the second valve, and the third valve based on a determination of whether or not the detected value of the first flow detector is an abnormal value and a determination of whether or not the detected value of the second flow detector is an abnormal value.

5. A liquid ejection system as described in claim 4, wherein the controller determines that an abnormality has occurred in the second valve when it determines that the detection value of the first flow rate detector is an abnormal value and the detection value of the second flow rate detector is a normal value, and determines that an abnormality has occurred in the third valve when it determines that the detection value of the first flow rate detector is a normal value and the detection value of the second flow rate detector is an abnormal value.

6. The liquid ejection system described in claim 4, wherein the controller calculates the difference between an estimated value calculated based on past values ​​of the detection value of the first flow detector and the latest value of the detection value of the first flow detector at multiple different times, and determines that the detection value of the first flow detector is an abnormal value if the calculated difference is greater than a threshold value over a predetermined number of times or more.

7. A liquid ejection system as described in claim 1 or 2, wherein the controller predicts the life of the first valve and / or the second valve based on the slope of the change over time in the detection value of the first flow detector, and / or predicts the life of the first valve and / or the third valve based on the slope of the change over time in the detection value of the second flow detector.

8. A liquid ejection system as described in claim 1 or 2, wherein the controller calculates the difference between an estimated value calculated based on past values ​​of the detection value of the first flow detector and the latest value of the detection value of the first flow detector at multiple different times, and if the calculated difference is greater than a threshold value over a predetermined number of times or more, predicts the life of the first valve and / or the second valve based on the slope of the change over time in the detection value of the first flow detector corresponding to the multiple times.

9. A liquid ejection system according to claim 1 or 2, wherein the controller predicts the life of a valve that is determined to be abnormal among the first valve, the second valve, and the third valve.

10. A liquid ejection system as described in claim 1 or 2, further comprising: a third flow path that supplies the liquid to the head and / or discharges the liquid from the head, the third flow path partially overlapping with the first flow path; a fourth valve that opens and closes the third flow path; and a third flow rate detector that detects the flow rate of the liquid flowing through the third flow path, wherein the second valve opens and closes the first flow path and the third flow path at the overlapping portion of the first flow path and the third flow path, and the fourth valve opens and closes the third flow path at a position different from the overlapping portion of the first flow path and the third flow path, and the controller determines whether or not there is an abnormality and / or predicts the lifespan of at least one of the first valve, the second valve, the third valve, and the fourth valve based on the detection value of the first flow rate detector and / or the detection value of the second flow rate detector and / or the detection value of the third flow rate detector.

11. The liquid ejection system according to claim 10, wherein the first flow rate detector also serves as the third flow rate detector.

12. A valve state determination method executed by a controller of a liquid ejection system that ejects liquid, wherein the liquid ejection system has: a head configured to eject the liquid; a first flow path that supplies the liquid to the head and / or discharges the liquid from the head; a second flow path that supplies the liquid to the head and / or discharges the liquid from the head, the second flow path partially overlapping with the first flow path; a first valve that opens and closes the first flow path and the second flow path at an overlapping portion between the first flow path and the second flow path; a second valve that opens and closes the first flow path at a position different from the overlapping portion; a third valve that opens and closes the second flow path at a position different from the overlapping portion; a first flow rate detector that detects the flow rate of the liquid flowing through the first flow path; and a second flow rate detector that detects the flow rate of the liquid flowing through the second flow path, and the valve state determination method determines the presence or absence of an abnormality and / or predicts the lifespan of at least one of the first valve, the second valve, and the third valve based on the detection value of the first flow rate detector and / or the detection value of the second flow rate detector.

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