Liquid ejection system and valve state determination method

Abstract

To provide a liquid ejection system of which configuration for performing valve state determination is realized at low cost.SOLUTION: A liquid ejection system comprises: a head; a first flow channel; a second flow channel of which a part overlaps with the first flow channel; a first valve which opens / closes the first flow channel and the second flow channel at an overlapping part between the first flow channel and the second flow channel; a second valve which opens / closes the first flow channel at a position different from the overlapping part; a third valve which opens / closes the second flow channel at a position different from the overlapping part; a first flow rate detector which detects a flow rate of a liquid flowing in the first flow channel; a second flow rate detector which detects a flow rate of the liquid flowing in the second flow channel; and a controller which perform determination of existence or absence of abnormality and life prediction for at least one of the first valve, the second valve and the third valve on the basis of a detection value of the first flow rate detector and / or a detection value of the second flow rate detector.SELECTED DRAWING: Figure 15

Description

[Technical Field]

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

[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 one 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 one valve. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-68033 Summary of the Invention [Problem to be solved by the invention]

[0005] In a configuration that requires multiple pressure sensors to determine the state of one valve, such as that disclosed in Patent Document 1, 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. [Means for solving the problem]

[0007] According to a first aspect of the present invention, A liquid ejection system that ejects a liquid, 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 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; A liquid ejection system is provided that includes 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 detector and / or the detection value of the second flow detector.

[0008] According to a second aspect of the present invention, A valve state determination method executed by a controller of a liquid ejection system that ejects liquid, comprising: The liquid ejection system includes: a head configured to eject the liquid; 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 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, A valve state determination method is provided 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 detector and / or the detection value of the second flow detector. [Effects of the Invention]

[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. [Brief explanation of the drawings]

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

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

[0012] <Printer 1000> 1, the printer 1000 mainly includes four head systems 100, a platen 200, transport rollers 301 and 302, an ink tank 400, a hydraulic pneumatics module (HPM) 500, an air pressure regulator 600, a controller 700, and a housing 800 that houses these components. The printer 1000 further includes a display unit 900 located on the outer surface of the housing 800.

[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 called the transport direction. Also, the direction extending in the horizontal plane and perpendicular to the transport direction is called 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-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 to the head system 100 (below) 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 a predetermined manner in the transport direction 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 sub-tank 20 (described later) of the head system 100. A total of four air pressure regulators 600 are provided, one for each head system 100 (only one is shown 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 an FPGA (Field Programmable Gate Array), an EEPROM (registered trademark) (Electrically Eracable Programmable Read-Only Memory), and a RAM (Random Access Memory). The controller 700 may also include a CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit). The controller 700 is connected to an external device (not shown) such as a PC so as to be able to communicate data with the printer 1000, and controls each part of the printer 1000 based on print data sent from the external device.

[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] <Head System 100> 2, each of the four head systems 100 mainly comprises a housing 10, a sub-tank 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] <Case 10> The housing 10 may be made of, for example, metal. The housing 10 includes a first housing 11 and a second housing 12 that is detachable from the first housing 11.

[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. Inside the first housing 11, a space S1 is defined that 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 on the upper part of the left wall 11e, and below the power connector CN, two air vents AP are arranged in the front-rear direction. 10 Two air vents AP 10 Below the ink flow port, there are two ink flow ports arranged in the front-to-back direction. 10 It is equipped with a power connector CN and two air vents AP. 10 and two ink flow ports IP 10 is omitted from FIG. 2.

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

[0033] <Subtank 20> The subtank 20 receives and stores the ink supplied to the head system 100. The ink stored in the subtank 20 is distributed to each of the multiple head 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 made up 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. The main body 21 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, a separation wall 21w is provided 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 shape of the top plate 22 in a plan view is the same as the outline shape of the main body 21 when viewed from above. The top plate 22 is fixed to the upper end of the main body 21 with a 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 sub-tank 20, the fill tank FT is formed by the front wall 21c, the partition wall 21w, the left wall 21e, and the right wall 21f of the main body 21, the top plate 22, and the bottom plate 23. The drain tank DT is formed by the rear wall 21d, the partition wall 21w, the left wall 21e, and the right wall 21f of the main body 21, the top plate 22, and the bottom plate 23. The internal space IN of the fill tank FT FT and the internal space of the drain tank DT DT are closed spaces and are separated from each other.

[0040] The left wall 21e has two ink flow ports IP 20 are arranged in the front-to-back direction. Front ink flow port IP 20 The internal space of the fill tank FT FT The ink flow port IP at the rear20 is the internal space of the drain tank DT DT It is connected to.

[0041] The top panel 22 has two air vents AP 20 are arranged in a line in the front-to-rear direction. 20 The internal space of the fill tank FT FT The rear air vent AP 20 is the internal space of the drain tank DT DT As shown in Figure 10, two air vents AP 20 are connected to the air vent AP at the rear of the housing 10 by a duct AT. 10 The air pressure regulator 600 is connected via

[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 port SP and the ink discharge port DP are aligned in the width direction.

[0043] A flow path (not shown) formed in the lower part of the inside of the main body 21 allows the internal space IN of the fill tank FT to FT are connected to the ink supply ports SP of each ink circulation port set S, and the internal space IN of the drain tank DT DT are in communication with the ink discharge ports DP of each ink flow port set S.

[0044] <Liquid level detection unit 30> 6, the liquid level detection unit 30 includes a fill tank sensor 31 that detects the position of the liquid level of the ink stored in the fill tank FT, and a drain tank sensor 32 that detects the position of the liquid 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 may be the top plate 22, bottom plate 23, etc. of the subtank 20. Similarly, the drain tank sensor 32 forms a pseudo-capacitor with the detection electrode 32E and a nearby grounded metal surface. The grounded metal surface may be, for example, a metal plate built into the drain tank sensor 32, or may be the top plate 22, bottom plate 23, etc. of the subtank 20.

[0047] In the fill tank sensor 31 and the drain tank sensor 32, the capacitance value of the pseudo capacitor is FT Position of the liquid surface in the internal space IN DT The fill tank sensor 31 and the drain tank sensor 32 each output the capacitance value of a pseudo capacitor to the controller 700.

[0048] <Head module 40> 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 that was 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 FIGS.

[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 above. As shown in FIG. 8, the flow path unit 431 includes a flow path CH 43 is formed.

[0053] Channel CH 43 8 ink flow ports IP 43 Each of the four manifold channels M1 to M4 is a linear channel, and has ink flow ports IP 43 Each of the four manifold channels M1 to M4 is connected to 12 individual channels iCH.

[0054] 8 ink outlets 43 Each of the head filters F HD is located. Head filter F HD is configured to remove foreign matter and air bubbles 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. On the nozzle surface 40n, a nozzle row L3 (FIG. 8) is formed 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. 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 Circuits) 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. An upper end portion 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). A lower end portion of the wiring connection portion WC is connected to a 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 pipe 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 pipe IST is connected to the ink supply pipe connection part ISC of the head module 40. The upper end of each ink discharge pipe 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 pipe IDT is connected to the ink discharge pipe connection part IDC of the head module 40.

[0062] The 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 through the ink flow port IP of the head 43. 43 flows into

[0063] The flow paths of the main body 42 are configured so that ink supplied to an ink supply pipe connection portion ISC flows through the manifold flow paths M1-M4, and ink discharged from the manifold flow paths M1-M4 flows to an ink discharge pipe connection portion IDC. The manifold flow paths M1-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 relays between a 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 area 11a2 of the top panel 11a in parallel to the second area 11a2. That is, the mounting surface of the relay board 50 is parallel to the upper and lower surfaces of the second area 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 an opening (not shown) provided in the bottom plate 12b of the second housing 12. The second housing 12 is attached to and detached from the first housing 11 by attaching and detaching the terminals to and from a connector (not shown) of the relay board 50 through an opening (not shown) provided in the second region 11a2 of the top plate 11a of the first housing 11.

[0069] <hpm500> 1, each of the four HPMs 500 (Hydraulic Pneumatics Modules) 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 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 F. HPM and mainly provide for.

[0071] The flow channel CH1 connects the main tank 410 and the suction port PA of the pump P. The flow channel CH2 connects the main tank 410 and the suction port IP 10 and the ink flow port IP on the front side of the subtank 20 20 The flow path CH3 connects the outlet PB of the pump P to the fill tank FT via the ink flow port IP 10 and the ink flow port IP on the rear side of the subtank 20 20 The flow channel CH2 and the drain tank DT are connected via the flow channel CH4. The flow channel CH1 and the flow channel CH3 are connected via the flow channel CH5. The flow channel CH2 and the main tank 410 are connected via the flow channel CH5.

[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] HPM Filter F HPM 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 via flow paths CH1 and CH2 to the fill tank FT is referred to as the supply flow path SCH (FIG. 11). When the HPM 500 configures 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 via flow path CH3, branch J3, flow path CH4, branch J2, and flow path CH2 to the fill tank FT is referred to as the circulation flow path CCH (FIG. 12). When the HPM 500 configures 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 via flow path CH3, branch J3, flow path CH4, branch J2, flow path CH1, flow path CH2, branch J4, and flow path CH5 to the main tank 410 is referred to as the discharge flow path DCH (FIG. 13). When the HPM 500 configures 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] In addition, from the fill tank FT, the ink supply pipe IST, the flow path CH of the head 43 43 The flow path that passes through the ink discharge pipe IDT and reaches the drain tank DT is called the 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 while opening valves Va and Vb of the HPM 500 and closing valves Vc to Ve, 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 is connected to the inner space IN of the fill tank FT. FT The air pressure in the air layer (the area where air exists above the ink surface) DT The ink in the fill tank FT is then sent to the head flow channel HCH via the ink supply pipe IST. 43 In the head 43, the ink that is not ejected from the nozzles 3 is sent to the drain tank DT via the ink discharge pipe IDT.

[0081] 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, thereby forming an image on the medium PM according to the print data.

[0083] <Valve state determination process> In the printer 1000 of this embodiment, the valve state determination process executed by the controller 700 will be described. First, the significance of determining the state of the valve will be described.

[0084] Each of the valves Va to Ve included 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] In the valves Va to Ve, if the O-rings OR are in contact with the ink for a long period of time, the O-rings OR may swell due to factors such as material compatibility. In this case, the flow resistance of the flow path CH increases, and even if the valves Va to Ve are open, there may not be enough ink flowing through the flow path CH. This type of swelling of the O-rings OR is more 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, "repeatedly execute" 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 period for periodic determination and the interval between two consecutive determination processes in non-periodic determination 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. Therefore, 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 are collectively referred to as a "valve group."

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

[0092] In the supply flow path flow rate detection step 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 Q SCH In the circulation channel flow rate detection step S102, the controller 700 detects the flow rate of ink flowing through the circulation channel CCH (hereinafter referred to as the "circulation channel flow rate Q CCH In the discharge flow path flow rate detection step 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 Q DCH ") is detected.

[0093] Here, in each 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, the controller 700 of this embodiment calculates 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 Q. SCH , circulation flow rate Q CCH , discharge flow rate Q DCH Detect as.

[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 increase in the amount of ink stored in the fill tank FT during the period PP is large, the increase in the detected value of the fill tank sensor 31 will also be large, resulting in a large 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 will also be small, and if the increase in the amount of ink stored in the fill tank FT during the period PP is zero, the slope X will also be zero. Also, if the amount of ink stored in the fill tank FT decreases during the period PP, the slope X will be 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 ink outflow from the fill tank FT is zero, the slope X of the detection value of the fill tank sensor 31 has a magnitude corresponding to the amount of ink inflow into the fill tank FT. Similarly, when the ink inflow into the drain tank DT is zero, the slope Y of the detection value of the drain tank sensor 32 has a magnitude corresponding to the amount of ink outflow from the drain tank DT. Therefore, the controller 700 converts the values ​​of the slopes X and Y detected, for example, in the following manner, into the supply flow path flow rate Q. SCH , circulation flow rate Q CCH , discharge flow rate Q DCH It can be treated as a value indicating

[0100] In the supply flow path flow rate detection step S101, the controller 700 configures the supply flow path SCH by opening the valves Va and Vb and closing the valves Vc to Ve. Then, the controller 700 drives the pump P in a state where the supply of ink from the fill tank FT to the head module 40 is stopped, 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 supply flow path flow rate Q SCH The controller 700 also supplies ink from the fill tank FT to the drain tank DT via the head flow channel HCH, and the supply flow channel flow rate Q SCH As a result, the gradient Y of the detection value of the drain tank sensor 32 may be detected.

[0101] In the circulation channel flow rate detection step S102, the controller 700 opens the valves Vb and Vd and closes the valves Va, Vc, and Ve to configure the circulation channel CCH. Then, the controller 700 drives the pump P in a state where the supply of ink from the fill tank FT to the head module 40 is stopped, and sends the ink in the drain tank DT to the fill tank FT via the circulation channel CCH. In this state, the controller 700 detects the circulation channel flow rate Q CCH The controller 700 detects the gradient X of the detection value of the fill tank sensor 31 as the gradient X. The controller 700 stops the discharge of ink from the head module 40 to the drain tank DT and reduces the circulation flow rate Q CCH As a result, the gradient Y of the detection value of the drain tank sensor 32 may be detected.

[0102] In the discharge flow path flow rate detection step S103, the controller 700 opens the valves Vd and Ve and closes the valves Va to Vc to configure the discharge flow path DCH. Then, the controller 700 drives the pump P in a state where the discharge of ink from the head module 40 to the drain tank DT is stopped, and sends the ink in the drain tank DT to the main tank 410 via the discharge flow path DCH. In this state, the controller 700 detects the discharge flow path flow rate Q DCH The controller 700 also supplies ink from the fill tank FT to the drain tank DT via the head flow path HCH, and the discharge flow path flow rate Q DCH As a result, the slope X of the detection value of the fill tank sensor 31 may be detected.

[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 (for example, 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 supply flow path flow rate Q in a valve abnormality determination step S2 and a valve life prediction step S3, which will be described later. SCH 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 a plurality of 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, and store the average value of the detection values ​​over the plurality of sets in a storage unit (not shown). In this case, too, the stored average value is used as the supply flow path flow rate Q in the valve abnormality determination step S2 and the valve life prediction step S3, which will be described later. SCD The latest value of the circulation flow rate Q CCH The latest value of and the discharge flow rate Q DCH is used as the latest value of

[0104] <Valve abnormality determination process S2> In the valve abnormality determination step S2, the controller 700 determines the supply flow path flow rate Q detected in the flow rate detection step S1. SCH , circulation flow rate Q CCH , and the discharge flow rate Q DCH Based on the above, it is determined whether or not there is an abnormality in each of the valves Va, Vb, Vd, and Ve.

[0105] Here, the supply flow rate Q SCH , circulation flow rate Q CCH , and the discharge flow rate Q DCH The reason for determining whether or not there is an abnormality in the valves Va, Vb, Vd, and Ve based on the above is as follows.

[0106] When 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 may be caused by, for example, a filter (HPM filter F in this embodiment) disposed in the flow path. HPM ) due to gradual clogging.

[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 placed in the flow path and the increasing swelling of the O-ring OR equipped in the valve.

[0108] Therefore, the controller 700 detects the supply flow rate Q SCH , circulation flow rate Q CCH , and the discharge flow rate Q DCH Based on the presence or absence of an abnormality (more specifically, for example, the presence or absence of a change in the rate of decrease), it is determined whether or not an abnormality has occurred for each of the valves Va, Vb, Vd, and Ve.

[0109] The controller 700 executes the valve abnormality determination step S2 according to 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 of the flow path in steps S201, S202, S203, S206, S209, S210, and S213 of the flowcharts shown in FIGS. 20 and 21. In the following explanation of the flow rate abnormality determination step S25, the flow rate Q is the supply flow rate Q that is the target of abnormality determination. SCH , circulation flow rate Q CCH , and the discharge flow rate Q DCH means one of the following:

[0111] In step S251, the controller 700 calculates time-series data SD of the flow rate Q at each past determination timing (i.e., each valve state determination process executed in the past). Q Based on (Fig. 23), the time series data SD Q An approximation line AL passing through each data included in the data is calculated. The approximation line AL can be calculated using any linear approximation method such as the least squares method. The linear approximation method is not limited to finding an approximation line, but may be a method of finding an approximation curve. Note that the controller 700 calculates an approximation line AL by calculating an approximation line AL passing through each data included in the data. D The value of flow rate Q when it is determined to be greater than the time series data SD Q may be excluded from

[0112] In step S252, the controller 700 calculates the value on the calculated approximate line AL that corresponds to the current determination timing as the estimated value Q ES That is, the estimated value Q ES is an estimated value of the current flow rate Q 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 estimated value Q ES and the latest value of the flow rate Q detected in the flow rate detection step S1, and in step S254, the calculated difference D is compared with a threshold value TH D Compare with.

[0114] The controller 700 determines whether the difference D is greater than or equal to a threshold TH D If it is determined that the difference D is equal to or greater than the threshold value TH (S254: YES), in step S255, "1" is added to the cumulative value A. The cumulative value A is calculated by adding "1" to the cumulative value A when the difference D is equal to or greater than the threshold value TH D This is a value indicating the number of consecutive determination timings at which it is determined that the threshold is equal to or greater than the threshold (that is, the number of consecutive determination timings at which YES is determined in step S254).

[0115] In step S256, the controller 700 calculates the cumulative value A and the threshold value TH A The cumulative value A is compared with the threshold value TH A If it is equal to or greater than this (S256: YES), the controller 700 determines that the flow rate Q is abnormal (S257).

[0116] In step S254, the controller 700 determines whether the difference D is greater than or equal to the threshold TH D If it is determined that the flow rate Q is smaller than the threshold value TH (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. A If it is determined that the flow rate Q is smaller than the reference flow rate Q (S256: NO), the flow rate Q is determined to be normal in step S259.

[0117] In this way, in the flow rate abnormality determination step S25, the controller 700 compares the latest value of the flow rate Q detected in the flow rate detection step S1 with the estimated value Q of the flow rate Q based on the past detected values. ES If the difference between the flow rate Q and the actual flow rate Q is greater than the threshold value for more than a predetermined number of consecutive determination timings, it is determined that the flow rate Q in the flow path is abnormal. 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 controls the discharge flow rate Q DCH In step S201, the controller 700 determines whether there is an abnormality in the discharge flow path Q DCH If it is determined that there is an abnormality in the circulation flow path (S201: YES), in step S202, CCH In step S202, the controller 700 determines whether there is an abnormality in the circulation flow path Q CCH If it is determined that there is an abnormality in the supply flow path (S202: YES), in step S203, SCH It is determined whether or not there is an abnormality in the flow rate in accordance with the flow rate abnormality determination step S25.

[0120] In step S203, the controller 700 calculates the supply flow rate Q SCH If it is determined that there is an abnormality in the valve group (S203: YES), in step S204, it is determined that the valve group is in the first state. When the valve group is in the first state, valve Va, valve Vb, valve Vd, and valve Ve are in one of the following states. (1) Valve Va and valve Vd are abnormal, and other valves are normal. (2) Valves Vb and Vd are abnormal, and the other valves are normal. (3) Valve Vb and valve Ve are abnormal, and 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) Valve Va, Valve Vb, Valve Vd, and Valve Ve are all abnormal.

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

[0122] In step S202, the controller 700 calculates the circulation flow rate Q CCH If it is determined that the flow rate of the supply flow path Q is normal (S202: NO), in step S206, SCH It is determined whether or not there is an abnormality in the flow rate determination step S25.

[0123] In step S206, the controller 700 calculates the supply flow rate Q SCH If it is determined that there is an abnormality (S206: YES), in step S207, it is determined 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] In step S206, the controller 700 calculates the supply flow rate Q SCH If it is determined that the valves are normal (S206: NO), it is determined 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] In step S201, the controller 700 calculates the discharge flow rate Q DCH If it is determined that the flow rate of the circulation flow path Q is normal (S201: NO), the flow rate of the circulation flow path Q is CCH It is determined whether or not there is an abnormality in the flow rate determination step S25.

[0126] The controller 700 controls the circulation flow rate Q CCH If it is determined that there is an abnormality in the supply flow path (S209: YES), in step S210, SCH In accordance with the flow rate determination step S25, the controller 700 determines whether or not there is an abnormality in the supply flow rate. If it is determined that there is an abnormality in the supply flow rate (S210: YES), the controller 700 determines in step S211 that the valve group is in the fifth state. When the valve group is in the fifth state, the 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) Valve Va and valve Vb are abnormal, and other valves are normal.

[0127] In step S210, the controller 700 calculates the supply flow rate Q SCH If it is determined that the valves Va, Vb, Vd, and Ve are normal (S210: NO), the valve group is determined to be in the sixth state in step S212. When the valve group is in the sixth state, the states of valves Va, Vb, Vd, and Ve are unknown. In other words, the determination that the valve group is in the sixth state is an error determination. In the sixth state, the supply flow path flow rate Q SCH There is no abnormality in the circulation flow path Q CCH Since there is an abnormality in the valve Vd, it is presumed that there is an abnormality in the valve Vd. On the other hand, the discharge flow rate Q DCH Since there is no abnormality in valve Vd, it is estimated that there is no abnormality in valve Vd. In this way, contradictory assumptions are made in the sixth state, so it is thought that some kind of error has occurred.

[0128] In step S209, the controller 700 calculates the circulation flow rate Q CCH If it is determined that the flow rate of the supply flow path Q is normal (S209: NO), in step S213, SCH The controller 700 determines whether or not there is an abnormality in the supply flow path flow rate Q in accordance with the flow rate abnormality determination step S25. SCH If it is determined that there is an abnormality in valve Va, valve Vb, valve Vd, and valve Ve (YES in step S213), the valve group is determined to be in state 7. When the valve group is in state 7, valve Va is abnormal and the other valves are normal.

[0129] In step S213, the controller 700 calculates the supply flow rate Q SCH If it is determined that the valves Va, Vb, Vd, and Ve are normal (S213: NO), then in step S215, it is determined that the valve group is in state 8. When the valve group is in state 8, all of valves Va, Vb, Vd, and Ve are normal.

[0130] <Valve life prediction process S3> In the valve life prediction step S3, the controller 700 calculates the supply flow rate Q SCH , circulation flow rate Q CCH , and the discharge flow rate Q DCH Based on the above, the lifespan of each of the valves Va, Vb, Vd, and Ve is predicted.

[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 calculates the supply flow path flow rate Q SCH In step S302, the controller 700 calculates the supply flow rate Q SCH or circulation flow rate Q CCH In step S303, the controller 700 calculates the circulation flow rate Q CCH or discharge flow rate Q DCH In step S304, the controller 700 calculates the discharge flow rate Q DCH The life of the valve Ve is predicted based on this.

[0132] In each of steps S301 to S304, the controller 700 predicts the life of the valve in accordance with the life prediction process S35 shown in Fig. 25. In the following description of the life prediction process S35, the flow rate Q is the supply flow rate Q used in the life prediction. SCH , circulation flow rate Q CCH , and the discharge flow rate Q DCH means one of the following:

[0133] In step S351, the controller 700 calculates the time series data SD of the flow rate Q at each past prediction timing. Q1 The value on the approximation line AL1 calculated based on (Fig. 26(a)) that corresponds to the current predicted timing is the estimated value Q ES The approximate line AL1 can be the approximate line AL2 calculated in step S356 (to be described later) or the approximate line AL1 calculated in step S359 (to be described later) in the life prediction step S35 at the immediately previous prediction timing. 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 estimated value Q ES and the latest value of the flow rate Q detected in the flow rate detection step S1, a difference DD is calculated, and in step S353, the calculated difference DD is compared with a threshold value TH DD Compare with.

[0135] In step S353, the controller 700 determines whether the difference DD is greater than or equal to the threshold TH DD If it is determined that the difference DD is equal to or greater than the threshold value TH (S353: YES), "1" is added to the cumulative value AA in step S354. DD This is a value indicating the number of consecutive predicted timings that are determined to be equal to or greater than the predetermined threshold (that is, the number of consecutive predicted timings for which a YES determination is made in step S353).

[0136] In step S355, the controller 700 calculates the cumulative value AA and the threshold value TH AA The controller 700 compares the accumulated value AA with the threshold value TH AA If it is determined that the number is equal to or greater than this (S355: YES), the approximate line is recalculated in step S356.

[0137] Specifically, in step S356, the controller 700 determines whether the difference DD is greater than or equal to a threshold TH DD Time series data SD of flow rate Q at the timing of judgment of the cumulative value AA times immediately before it was judged to be equal to or greater than Q2 Based on (Fig. 26(b)), the time series data SD Q2 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 starts 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 finding an approximate straight line, but may also be one that finds 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] As shown in Figure 27, if the current operating time is operating time OH1 and the operating time at the point when the flow rate Q has dropped 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 is the lifespan LT of the valve V. V The controller 700 determines the life of the valve V as follows: V is calculated as the difference between the current operation time OH1 and the operation time OH2 corresponding to the point X at which the flow rate Q indicated by the approximation line AL2 reaches the lower limit value MIN.

[0140] In step S353, the controller 700 determines whether the difference DD is greater than or equal to the threshold TH DD If it is determined that the cumulative value AA is smaller than the threshold value TH (S353: NO), the controller 700 returns the cumulative value AA to "0" in step S358, and the process proceeds to step S359. AA If it is determined that the flow rate Q is smaller than the time-series data SD Q1 In other words, the previous approximation line AL1 is updated. Thereafter, in step S360, the controller 700 calculates the life LT of the valve V using the updated approximation line AL1. V The controller 700 calculates the life LT V is calculated in the same manner as in step S357.

[0141] In this way, in the life prediction step S3, the controller 700 predicts the life of the valve based on the tendency of the flow rate decrease based on past data. V The value is calculated before swelling occurs in the O-ring OR of the valve, and is essentially the HPM filter F HPM However, the life LT calculated in step S360 is V There is no problem if the value of LT is used as a predicted value of the valve life because it is considered to be a value shorter than the actual valve life. V The value reflects the decrease in flow rate caused by swelling of the valve's O-ring OR, and can be said to be a more accurate prediction value.

[0142] <Display process 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, on the display unit 900 using text information, an icon, or the like. In addition, the controller 700 displays the life LT calculated in the valve life prediction step S3 for each of the valves Va, Vb, Vd, and Ve. V The value of is displayed on the display unit 900.

[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 the valve state determination method of this embodiment, a fill tank sensor 31 for detecting the amount of liquid in the fill tank FT and a drain tank sensor 32 for detecting the amount of liquid in the drain tank DT are used to measure the supply flow path flow rate Q SCH , circulation flow rate Q CCH , and the discharge flow rate Q DCH The detected supply flow rate Q SCH , circulation flow rate Q CCH , and the discharge flow rate Q DCH The states of the valves Va, Vb, Vd, and Ve are determined (i.e., abnormality determination and lifespan prediction) using the above. Therefore, there is no need to provide a separate sensor for determining the state of each valve, and a configuration for determining the state of the valves can be realized at low cost.

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

[0146] [Variations] In the above embodiment, the following modifications can also be used.

[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. SCH , circulation flow rate Q CCH , and the discharge flow rate Q DCH 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 detection sensors. The fill tank sensor 31 and the drain tank sensor 32 may be any liquid level detection sensor (e.g., float type, optical type, radio wave type, etc.) that can detect the liquid level in the fill tank FT and the drain tank DT, respectively. Furthermore, the fill tank sensor 31 and the drain tank sensor 32 are not limited to liquid level detection sensors, but may be any liquid level sensor that can detect the liquid level in the fill tank FT and the drain tank DT, respectively. The liquid level sensor may be any liquid level sensor, and may be 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, for example. Note that the liquid level detection sensor is one aspect of the liquid level sensor. Regardless of the aspect having any liquid level sensor, the supply flow path flow rate Q can be calculated in the same way as in the above embodiment. SCH , circulation flow rate Q CCH , and the discharge flow rate Q DCH can be detected.

[0149] Another example is the supply flow rate Q SCH , circulation flow rate Q CCH , and the discharge flow rate Q DCH A flow rate sensor that detects at least one of the above may be disposed in at least one of the supply flow path SCH, the circulation flow path CCH, and the discharge flow path DCH.

[0150] Specifically, for example, the supply flow rate Q SCH A flow sensor for detecting the flow rate Q of the circulation flow path is disposed between the main tank 410 of the supply flow path SCH and the valve Va. CCH A flow sensor that detects the flow rate Q of the discharge flow path is placed between the valve Vb of the circulation flow path CCH and the fill tank FT. DCH Alternatively, a flow rate sensor for detecting the supply flow rate Q may be disposed between the valve Ve of the discharge flow path DCH and the main tank 410. SCH and circulation flow rate Q CCH A flow sensor that detects the flow rate Q of the discharge flow path is placed between the valve Vb and the fill tank FT, which is the overlapping portion of the supply flow path SCH and the circulation flow path CCH. DCH Alternatively, a flow rate sensor for detecting the supply flow rate Q may be disposed between the valve Ve of the discharge flow path DCH and the main tank 410. Alternatively, a single flow rate sensor disposed in an overlapping portion of the supply flow path SCH, the circulation flow path CCH, and the discharge flow path DCH (for example, in the region between the pump P and the degassing unit DU) may be used to measure the supply flow rate Q. SCH , circulation flow rate Q CCH , and the discharge flow rate Q DCH In addition, the supply flow rate Q SCH , circulation flow rate Q CCH , and the discharge flow rate Q DCH One or more flow sensors may be optionally positioned to detect at least one of the following:

[0151] In this way, even if a flow sensor is used in addition to the liquid volume sensor that detects 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 to be determined).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 the discharge flow path flow rate Q DCH , circulation flow rate Q CCH , supply flow rate Q SCH 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, 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 the valve Vd or that an abnormality has occurred in both the valve Vd and the valve Ve, the controller 700 determines the discharge flow path flow rate Q DCH The rate of decrease (the slope of the approximation line AL calculated in step S251) is compared with a threshold value. If the rate of decrease is equal to or greater than the threshold value, 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, 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 the number of valves having an abnormality is two, three, or four.

[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 an abnormality has occurred in the valve Vd or that an abnormality has occurred in both the valve Vd and the valve Ve, the controller 700 determines the discharge flow path flow rate Q DCH The amount of decrease (which may be the difference D calculated in the flow rate abnormality determination step S25 or may be the amount of decrease from the value at the previous determination timing) is used as a threshold (threshold value TH used in the flow rate abnormality determination step S25). D The controller 700 compares the valve Vd and valve Ve (which may be a value greater than the threshold value) with the valve Vd. If the amount of decrease is equal to or greater than the threshold value, the controller 700 determines that an abnormality has occurred in valve Vd and valve Ve, and if the amount 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 the number of valves having an abnormality is two, three, or four.

[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, and may determine that one valve is abnormal if the difference is smaller than the threshold.

[0159] Specifically, for example, after determining in step S205 that an abnormality has occurred in the valve Vd or that an abnormality has occurred in both the valve Vd and the valve Ve, the controller 700 determines whether the discharge flow rate Q of the discharge flow path DCH in which both the valve Vd and the valve Ve are located is DCH (which may be the difference D calculated in the flow rate abnormality determination step S25, or may be the amount of decrease from the value at the previous determination timing) and the circulation flow rate Q of the circulation flow path CCH where only the valve Vd is located. CCH The decrease in the discharge flow rate Q DCH and circulation flow rate Q CCH The difference between the amount of decrease in valve Vd and the amount of decrease in valve Ve is compared with a threshold value, and if the difference is greater than or equal to the threshold value, it is determined that an abnormality has occurred in valve Vd and valve Ve, and if the difference is smaller than the threshold value, it is determined that an abnormality has occurred in valve Vd only. The same applies to the steps executed after step S204 and step 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 whether the cumulative value A is greater than or equal to the threshold value TH A If it is equal to or greater than the threshold (S256: YES), it is determined that the flow rate Q is abnormal (S257). However, this is not limiting. The controller 700 may 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 (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. D If it is determined that the cumulative value A is smaller than the threshold (YES at step S254), the cumulative value A does not need to be reset to "0."

[0162] <Variations of the valve life prediction process> In the above embodiment, in the valve life prediction step S3, the controller 700 determines whether the cumulative value AA is greater than or equal to the threshold value TH AA If it is determined that the difference DD is equal to or greater than the threshold value TH, the approximation line is recalculated 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 has started 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 determines whether the recalculated approximation line is equal to or greater than the threshold value TH. DD The approximation line may be recalculated in any manner that reflects the gradient of the change in the flow rate Q over time at a plurality of determination timings at which it is determined that the flow rate Q is greater than .gtoreq..times.(step S353: YES).

[0163] Specifically, for example, the controller 700 determines whether the difference DD is greater than or equal to a threshold TH DD The flow rate Q0 (FIG. 26(b)) at the judgment timing one time before the first judgment timing at which the flow rate was judged to be greater than 10 ... Q2 Alternatively, the controller 700 may use the flow rate Q at a determination timing before the determination timing at which the flow rate Q0 is detected as the time series data SD Q2 Even in such a case, if the slope of the recalculated approximation line is larger than the slope of the approximation line before recalculation, it can be said that the influence of the valve abnormality is reflected. Therefore, the recalculated approximation line is DD It can be said that this reflects the gradient of the change in the flow rate Q over time at multiple determination timings at which it is determined to be greater than .

[0164] In the valve life prediction step S3 of the above embodiment, the controller 700 may calculate the difference between the slope of the approximate line before recalculation and the slope of the recalculated approximate line after recalculating the approximate line in step S356. If the calculated difference is equal to or greater than a threshold value (i.e., if the amount of change in slope is equal to or greater than a threshold value), the controller 700 determines whether the recalculated approximate line is in a state where the difference DD is equal to or greater than the threshold value TH. DD On the other hand, if the calculated difference is smaller than the threshold value (i.e., if the amount of change in the slope is smaller than the threshold value), the controller 700 may perform a life prediction using the HPM filter F. HPM It may be determined that a large foreign object has become stuck in the DD This is because, when the slope of the approximation line recalculated based on the flow rate Q at a plurality of determination timings determined to be greater than 1 is similar to the slope of the approximation line before recalculation, there is a possibility that a stepwise decrease in the flow rate Q due to filter clogging has occurred, 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. DD If it is determined that the cumulative value AA is smaller than the predetermined value (YES at step S353), 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 the 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 time point of determination) on the approximate curve.

[0167] <Other variations> In the above embodiment, the controller 700 targets the valves Va, Vb, Vd, and Ve for state determination, but this is not limited thereto. 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 determine the state of the valves Vb, Vd, and Ve. 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 modifications, 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] If 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 limited to this. For example, a controller constructed outside 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 constructed outside 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, flow rate abnormalities may occur when foreign matter gets caught in the valve drive unit or when valve components (such as springs) deteriorate, causing the valve to malfunction. Alternatively, in the case of a valve that performs its opening and closing function by the elasticity (sealing properties) of rubber, flow rate abnormalities may occur when the rubber swells due to material compatibility when exposed to ink.

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

[0179] (Item 1) A liquid ejection system that ejects a liquid, 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 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.

[0180] (Item 2) 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 tank that stores the liquid supplied to the head and / or the liquid discharged from the head; the first flow path and the second flow path are connected to the tank, 3. The liquid ejection system according to item 1 or 2, wherein at least one of the first flow rate detector and the second flow rate detector is a liquid volume sensor that detects the amount of the liquid stored in the tank.

[0182] (Item 4) The 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 detector is an abnormal value and a determination of whether or not the detection value of the second flow detector is an abnormal value.

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

[0184] (Item 6) The controller calculating, at a plurality of different timings, a difference between an estimated value calculated based on past values ​​of the detected value of the first flow rate detector and a latest value of the detected value of the first flow rate detector; 6. The liquid ejection system according to item 4 or 5, wherein the detected value of the first flow rate detector is determined to be an abnormal value when the calculated difference is greater than a threshold value over a predetermined number of or more timings.

[0185] (Item 7) The 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) The controller calculating, at a plurality of different timings, a difference between an estimated value calculated based on past values ​​of the detected value of the first flow rate detector and a latest value of the detected value of the first flow rate detector; A liquid ejection system described in any one of items 1 to 7, wherein if the calculated difference is greater than a threshold value over a predetermined number of timings or more, the lifespan of the first valve and / or the second valve is predicted based on the gradient of the change over time in the detection value of the first flow detector corresponding to the multiple timings.

[0187] (Item 9) The liquid ejection system according to any one of items 1 to 8, wherein the controller predicts the life span of a valve determined to be abnormal among the first valve, the second valve, and the third valve.

[0188] (Item 10) 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 the first flow path; a fourth valve that opens and closes the third flow path; a third flow rate detector that detects a flow rate of the liquid flowing through the third flow path, 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; the fourth valve opens and closes the third flow path at a position different from an overlapping portion between the first flow path and the third flow path, The liquid ejection system described in any one of items 1 to 9, wherein 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 detector and / or the detection value of the second flow detector and / or the detection value of the third flow detector.

[0189] (Item 11) 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] (Item 12) A valve state determination method executed by a controller of a liquid ejection system that ejects liquid, comprising: The liquid ejection system includes: a head configured to eject the liquid; 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 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, A valve state determination method for determining whether or not there is an abnormality and / or predicting 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 detector and / or the detection value of the second flow detector. [Explanation of symbols]

[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 tanks 500 HPM 700 Controller 1000 printers DT drain tank Va, Vb, Vc, Vd, Ve valve FT Fill Tank P pump

Claims

1. A liquid ejection system that ejects a liquid, 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 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; 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 detector and / or the detection value of the second flow 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 tank that stores the liquid supplied to the head and / or the liquid discharged from the head, the first flow path and the second flow path are connected to the tank, 3. The liquid ejection system according to claim 1, wherein at least one of the first flow rate detector and the second flow rate detector is a liquid amount sensor that detects the amount of the liquid stored in the tank.

4. The liquid ejection system 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 detection value of the first flow detector is an abnormal value and a determination of whether or not the detection value of the second flow detector is an abnormal value.

5. The controller determining that an abnormality has occurred in the second valve when it is determined 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; The liquid ejection system according to claim 4 , wherein it is determined that an abnormality has occurred in the third valve when it is determined that the detected value of the first flow rate detector is a normal value and the detected value of the second flow rate detector is an abnormal value.

6. The controller calculating, at a plurality of different timings, a difference between an estimated value calculated based on past values ​​of the detected value of the first flow rate detector and a latest value of the detected value of the first flow rate detector; The liquid ejection system according to claim 4 , wherein the detected value of the first flow rate detector is determined to be an abnormal value when 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. The controller calculating, at a plurality of different timings, a difference between an estimated value calculated based on past values ​​of the detected value of the first flow rate detector and a latest value of the detected value of the first flow rate detector; A liquid ejection system as described in claim 1 or 2, wherein if the calculated difference is greater than a threshold value for a predetermined number of or more timings, the life of the first valve and / or the second valve is predicted based on the slope of the change over time in the detection value of the first flow detector corresponding to the multiple timings.

9. 3. The liquid ejection system according to claim 1, wherein the controller predicts the life of a valve that is determined to have an abnormality among the first valve, the second valve, and the third valve.

10. 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 the first flow path; a fourth valve that opens and closes the third flow path; a third flow rate detector that detects a flow rate of the liquid flowing through the third flow path, 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; the fourth valve opens and closes the third flow path at a position different from an overlapping portion between the first flow path and the third flow path, The liquid ejection system described in claim 1 or 2, wherein 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 detector and / or the detection value of the second flow detector and / or the detection value of the third flow 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, comprising: The liquid ejection system includes: 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 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, A valve state determination method for determining whether or not there is an abnormality and / or predicting 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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