Liquid discharge device and liquid storage device

Abstract

To detect a residual quantity of liquid in a storage container.SOLUTION: A liquid discharge device includes: a storage container configured to store conductive liquid; a first electrode housed in the first liquid chamber of the storage container; a second electrode housed in the second liquid chamber of the storage container; a partition wall housed in the storage container and partitioning the first liquid chamber from the second liquid chamber; a detection part which is electrically connected to the first electrode and the second electrode and outputs a detection signal generated according to an electric signal from one of the first electrode and the second electrode; and an identification part which identifies the residual quantity of the liquid stored in the storage container on the basis of the detection signal. A first opening allowing communication between the first liquid chamber and the second liquid chamber is formed below the partition wall. A second opening allowing communication between the first liquid chamber and the second liquid chamber is formed above the partition wall. When the liquid stored in the storage container exists in the first opening and the second opening, the first electrode and the second electrode contact with the liquid stored in the storage container.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a liquid ejection device and a liquid storage device.

Background Art

[0002] Various techniques for detecting the remaining amount of liquid in a storage container that stores a conductive liquid such as ink have been proposed. For example, Patent Document 1 proposes a technique for detecting the remaining amount of liquid in a storage container based on the resistance value between two rod-shaped electrode pins provided in the storage container that stores the liquid.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology, since the change amount of the resistance value between the two electrode pins is smaller than the change amount of the remaining amount of the liquid in the storage container, it has been difficult to detect the remaining amount of the liquid in the storage container in some cases.

Means for Solving the Problems

[0005] In order to solve the above problems, a liquid ejection device according to the present invention includes a storage container that stores a conductive liquid, a first electrode stored in a first liquid chamber of the storage container, a second electrode stored in a second liquid chamber of the storage container, a partition wall stored in the storage container that partitions the first liquid chamber and the second liquid chamber, a detection unit that is electrically connected to the first electrode and the second electrode and outputs a detection signal according to an electrical signal from one of the first electrode and the second electrode, and a specifying unit that specifies the remaining amount of the liquid stored in the storage container based on the detection signal. A first opening that communicates the first liquid chamber and the second liquid chamber is formed downward of the partition wall, and a second opening that communicates the first liquid chamber and the second liquid chamber is formed upward of the partition wall. When the liquid stored in the storage container is present in the first opening and the second opening, the first electrode and the second electrode are in contact with the liquid stored in the storage container.

[0006] Further, a liquid storage device according to the present invention includes a storage container that stores a conductive liquid, a first electrode stored in a first liquid chamber of the storage container, a second electrode stored in a second liquid chamber of the storage container, a partition wall stored in the storage container that partitions the first liquid chamber and the second liquid chamber, and a detection unit that is electrically connected to the first electrode and the second electrode and outputs a detection signal according to an electrical signal from one of the first electrode and the second electrode. A first opening that communicates the first liquid chamber and the second liquid chamber is formed downward of the partition wall, and a second opening that communicates the first liquid chamber and the second liquid chamber is formed upward of the partition wall. When the liquid stored in the storage container is present in the first opening and the second opening, the first electrode and the second electrode are in contact with the liquid stored in the storage container.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 6

Figure 7

Figure 8

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Figure 11

Figure 12

Best Mode for Carrying Out the Invention

[0008] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, in each figure, the dimensions and scales of each part are appropriately different from the actual ones. Further, the embodiments described below are preferred specific examples of the present invention, and thus various technically preferable limitations are imposed. However, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description to limit the present invention.

[0009] <<A. Embodiment>> Hereinafter, the inkjet printer 100 according to the present embodiment will be described.

[0010] <<1. Outline of Inkjet Printer>> FIG. 1 is an explanatory diagram showing an example of the configuration of an inkjet printer 100 according to the present embodiment.

[0011] The inkjet printer 100 is a printing apparatus of an inkjet method that discharges ink IK onto a medium PP. The medium PP is typically printing paper, but any printing target such as a resin film or fabric can be used as the medium PP. In the present embodiment, conductive ink is employed as the ink IK. Note that in the present embodiment, the inkjet printer 100 is an example of a "liquid discharge device", and the ink IK is an example of a "conductive liquid".

[0012] As shown in FIG. 1, the inkjet printer 100 includes an ink storage device 1, a control device 8, a plurality of liquid discharge heads HU, a conveyance mechanism 91, and a movement mechanism 92.

[0013] The control device 8 includes, for example, a processing circuit such as a CPU or an FPGA and a storage circuit such as a semiconductor memory, and controls each element of the inkjet printer 100. Here, the CPU is an abbreviation for Central Processing Unit, and the FPGA is an abbreviation for Field Programmable Gate Array.

[0014] The conveyance mechanism 91 conveys the medium PP in the sub-scanning direction MP1 based on the control by the control device 8. The movement mechanism 92 reciprocates the plurality of liquid discharge heads HU in the main scanning direction MH1 intersecting the sub-scanning direction MP1 and the main scanning direction MH2 opposite to the main scanning direction MH1 based on the control by the control device 8. The movement mechanism 92 includes a storage case 921 that houses the plurality of liquid discharge heads HU and an endless belt 922 to which the storage case 921 is fixed. Note that the storage case 921 may house the ink storage device 1 together with the liquid discharge heads HU.

[0015] The control device 8 supplies a drive signal Com for driving the liquid ejection head HU and a control signal SI for controlling the liquid ejection head HU to the liquid ejection head HU.

[0016] The liquid ejection head HU is driven by the drive signal Com based on the control by the control signal SI, and ejects ink IK from some or all of a plurality of nozzles provided in the liquid ejection head HU. That is, the liquid ejection head HU ejects ink IK from some or all of the plurality of nozzles in conjunction with the conveyance of the medium PP by the conveyance mechanism 91 and the reciprocating movement of the liquid ejection head HU by the movement mechanism 92, and lands the ejected ink on the surface of the medium PP, thereby forming a desired image on the surface of the medium PP.

[0017] The ink storage device 1 stores the ink IK. Further, the ink storage device 1 supplies the ink IK stored in the ink storage device 1 to the liquid ejection head HU based on the control by the control device 8. Note that in the present embodiment, the ink storage device 1 is an example of a "liquid storage device".

[0018] In the present embodiment, it is assumed that the ink storage device 1 stores M types of ink IK. Here, the value M is a natural number satisfying 1 ≦ M. More specifically, in the present embodiment, as an example, it is assumed that the ink storage device 1 stores four types of ink IK corresponding to cyan, magenta, yellow, and black. That is, in the present embodiment, as an example, the case of "M = 4" is assumed.

[0019] In the present embodiment, it is assumed that the inkjet printer 100 includes M liquid ejection heads HU corresponding to M types of ink IK. Specifically, in the present embodiment, as an example, it is assumed that the inkjet printer 100 includes four liquid ejection heads HU corresponding to four types of ink IK. Incidentally, hereinafter, among the M liquid ejection heads HU, the m-th liquid ejection head HU may be referred to as the liquid ejection head HU[m]. Here, the variable m is a natural number satisfying 1 ≦ m ≦ M.

[0020] The ink storage device 1 includes an ink amount detection circuit 2 that detects the remaining amounts of various types of ink IK stored in the ink storage device 1 and outputs an output signal Vout indicating the detection result. The ink amount detection circuit 2 will be described later with reference to FIG. 3. Incidentally, in the present embodiment, the output signal Vout is an example of a "detection signal".

[0021] <<2. Ink Storage Device>> Hereinafter, an overview of the ink storage device 1 will be described with reference to FIGS. 2 to 7.

[0022] FIG. 2 is a perspective view for explaining an example of the configuration of the ink storage device 1.

[0023] As shown in FIG. 2, the ink storage device 1 includes M ink tanks TK that correspond one-to-one with the M types of ink IK stored in the ink storage device 1, and a storage case 11 that stores the M ink tanks TK. Specifically, in the present embodiment, the ink storage device 1 includes four ink tanks TK that correspond one-to-one with four types of ink IK: cyan, magenta, yellow, and black. Incidentally, in the present embodiment, the ink tank TK is an example of a "storage container".

[0024] Hereinafter, among the M ink tanks TK, the m-th ink tank TK may be referred to as the ink tank TK[m]. The ink tank TK[m] stores the type of ink IK corresponding to the ink tank TK[m] and supplies the ink IK to the liquid ejection head HU[m] corresponding to the ink tank TK[m].

[0025] In this embodiment, the ink tank TK is provided with a supply port 12 for supplying ink IK to the internal space of the ink tank TK. Further, the ink tank TK houses an electrode rod BT and an electrode rod BK, which are rod-shaped electrodes, and a partition wall WL for partitioning the internal space of the ink tank TK. In this embodiment, the electrode rod BT is an example of the "first electrode", and the electrode rod BK is an example of the "second electrode".

[0026] Hereinafter, when ink IK is supplied from the ink tank TK to the liquid ejection head HU and the ink IK stored inside the ink tank TK decreases, the direction in which the ink IK decreases in the ink tank TK is referred to as the Z1 direction. In this embodiment, as an example, a case where the electrode rod BT and the electrode rod BK are provided so as to extend in the Z1 direction in the ink tank TK is assumed. Hereinafter, the Z1 direction and the Z2 direction opposite to the Z1 direction are collectively referred to as the Z-axis direction. In this embodiment, the Z1 direction is an example of the "downward direction", and the Z2 direction is an example of the "upward direction".

[0027] FIG. 3 is a circuit diagram showing an example of the configuration of the ink storage device 1. In this embodiment, a case where M ink amount detection circuits 2 corresponding one-to-one to M ink tanks TK[1] to TK[M] are provided in the ink storage device 1 is assumed. In this embodiment, the ink amount detection circuit 2 is an example of the "detection unit".

[0028] As shown in FIG. 3, the ink amount detection circuit 2 includes an output circuit 20, an input terminal TnN, a detection terminal TnK, a reference potential connection terminal TnT, and an output terminal TnS.

[0029] The output circuit 20 includes a node NK and an input resistor RN provided between the input terminal TnN and the node NK.

[0030] The node NK is electrically connected to the input terminal TnN, the detection terminal TnK, and the output terminal TnS. The detection terminal TnK is electrically connected to the electrode rod BK via the detection wiring LK. The reference potential connection terminal TnT is electrically connected to the ground wiring set to the ground potential and is also electrically connected to the electrode rod BT via the reference potential connection wiring LT.

[0031] As described above, the ink tank TK houses the electrode rod BT, the electrode rod BK, and the partition wall WL. The partition wall WL divides the internal space of the ink tank TK for housing the ink IK into an ink liquid chamber RM1 and an ink liquid chamber RM2. The electrode rod BT is housed in the ink liquid chamber RM1. The electrode rod BK is housed in the ink liquid chamber RM2. A lower opening OP1 for communicating the ink liquid chamber RM1 and the ink liquid chamber RM2 is formed in the Z1 direction of the partition wall WL. An upper opening OP2 for communicating the ink liquid chamber RM1 and the ink liquid chamber RM2 is formed in the Z2 direction of the partition wall WL. In the present embodiment, the ink liquid chamber RM1 is an example of the "first liquid chamber", the ink liquid chamber RM2 is an example of the "second liquid chamber", the lower opening OP1 is an example of the "first opening", and the upper opening OP2 is an example of the "second opening".

[0032] In the present embodiment, when the ink IK is housed in the ink tank TK and the electrode rod BT and the electrode rod BK come into contact with the ink IK housed in the ink tank TK, the electrode rod BT and the electrode rod BK are electrically connected via the ink IK housed in the ink tank TK. Hereinafter, when the electrode rod BT and the electrode rod BK are electrically connected via the ink IK present in the lower opening OP1 among the ink IK housed in the ink tank TK, the electrical resistance of the ink IK that electrically connects the electrode rod BT and the electrode rod BK through the path via the lower opening OP1 is referred to as the ink resistance RT1. Also, hereinafter, when the electrode rod BT and the electrode rod BK are electrically connected via the ink IK present in the upper opening OP2 among the ink IK housed in the ink tank TK, the electrical resistance of the ink IK that electrically connects the electrode rod BT and the electrode rod BK through the path via the upper opening OP2 is referred to as the ink resistance RT2.

[0033] In this embodiment, an input signal Vin set to a constant input potential VN is input to the input terminal TnN. Therefore, when the electrode bar BT and the electrode bar BK are electrically connected via the ink IK accommodated in the ink tank TK, the potential of the node NK is determined based on the input potential VN of the input signal Vin, the resistance value of the input resistor RN, and the combined resistance value of the ink resistors RT1 and RT2. In this embodiment, since the input potential VN of the input signal Vin and the resistance value of the input resistor RN are constant values, the potential of the node NK is determined based on the combined resistance value of the ink resistors RT1 and RT2. Then, an output signal Vout indicating the potential of the node NK is output from the output terminal TnS.

[0034] In this embodiment, the control device 8 specifies the remaining amount of the ink IK accommodated in the ink tank TK based on the output signal Vout output by the output circuit 20. Note that, in this embodiment, the control device 8 is an example of the "specifying unit".

[0035] FIG. 4 and FIG. 5 are configuration diagrams showing an example of the configuration of the ink tank TK.

[0036] As shown in FIGS. 4 and 5, the ink tank TK accommodates an electrode bar BT. The electrode bar BT is made of a conductive material and is electrically connected to the reference potential connection wiring LT on the upper surface TU of the ink tank TK. Then, the electrode bar BT is provided such that the distance in the Z-axis direction from the end portion of the electrode bar BT in the Z1 direction to the bottom surface TM of the ink tank TK is the distance H1.

[0037] As shown in FIGS. 4 and 5, the ink tank TK accommodates an electrode bar BK. The electrode bar BK is made of a conductive material and is electrically connected to the detection wiring LK on the upper surface TU of the ink tank TK. Then, the electrode bar BK is provided such that the distance in the Z-axis direction from the end portion of the electrode bar BK in the Z1 direction to the bottom surface TM of the ink tank TK is the distance H1.

[0038] As shown in FIGS. 4 and 5, a partition wall WL is accommodated in the ink tank TK. The partition wall WL is made of an insulating material. However, the partition wall WL may be formed of a conductive substance having a higher resistance value per unit volume than the ink IK. In the present embodiment, as an example, it is assumed that the partition wall WL is provided such that the distance in the Z-axis direction from the end portion of the partition wall WL in the Z1 direction to the bottom surface TM of the ink tank TK is the distance HE, and the distance in the Z-axis direction from the end portion of the partition wall WL in the Z2 direction to the bottom surface TM of the ink tank TK is the distance H2. That is, in the present embodiment, as an example, it is assumed that the partition wall WL is provided such that the lower opening OP1 extends in the range of the distance in the Z-axis direction from the bottom surface TM from "0" to the distance HE, and the upper opening OP2 extends in the range of the distance in the Z-axis direction from the bottom surface TM from the distance H2 to the distance HF. Here, the distance HF is the distance in the Z-axis direction from the bottom surface TM to the upper surface TU. The distance HE is a distance shorter than the distance H1. The distance H2 is a distance longer than the distance H1 and shorter than the distance HF. In the present embodiment, it is assumed that the difference value obtained by subtracting the distance H2 from the distance HF is larger than the distance HE. That is, in the present embodiment, it is assumed that the cross-sectional area of the lower opening OP1 is smaller than the cross-sectional area of the upper opening OP2 when the lower opening OP1 and the upper opening OP2 are cut by a plane perpendicular to the direction from the ink liquid chamber RM1 to the ink liquid chamber RM2.

[0039] In addition, in the present embodiment, it is assumed that the electrode rods BT and BK are provided such that the distance in the Z-axis direction from the bottom surface TM to the electrode rod BT and the distance in the Z-axis direction from the bottom surface TM to the electrode rod BK are both the distance H1. However, the present invention is not limited to such a mode. The electrode rods BT and BK may be provided such that the longer of the distance in the Z-axis direction from the bottom surface TM to the electrode rod BT and the distance in the Z-axis direction from the bottom surface TM to the electrode rod BK is the distance H1. Further, in the present embodiment, it is assumed that the distance H1 is longer than the distance HE. However, the present invention is not limited to such a mode. The distance H1 may be shorter than the distance HE.

[0040] Hereinafter, the distance in the Z-axis direction from the bottom surface TM of the ink tank TK to the liquid surface SF of the ink IK accommodated in the ink tank TK is referred to as the ink liquid surface distance SZ.

[0041] As shown in FIG. 4, when the ink liquid surface distance SZ is equal to or greater than the distance H1 and less than the distance H2, the ink IK is present in the lower opening OP1. And when the ink liquid surface distance SZ is equal to or greater than the distance H1, the electrode rods BT and BK are electrically connected by the ink IK present in the lower opening OP1. Therefore, when the ink liquid surface distance SZ is equal to or greater than the distance H1 and less than the distance H2, the electrical resistance of the ink IK that electrically connects the electrode rods BT and BK is the ink resistance RT1.

[0042] As shown in FIG. 5, when the ink liquid surface distance SZ is equal to or greater than the distance H2, the ink IK is present in the lower opening OP1 and the upper opening OP2. And when the ink liquid surface distance SZ is equal to or greater than the distance H2, the electrode rods BT and BK are electrically connected by the ink IK of the ink resistance RT1 present in the lower opening OP1 and are also electrically connected by the ink IK of the ink resistance RT2 present in the upper opening OP2. Therefore, when the ink liquid surface distance SZ is equal to or greater than the distance H2, the electrical resistance of the ink IK that electrically connects the electrode rods BT and BK is the combined resistance of the ink resistance RT1 and the ink resistance RT2 when the ink resistance RT1 and the ink resistance RT2 are connected in parallel.

[0043] Hereinafter, the combined resistance of ink resistors RT1 and RT2 is referred to as ink resistor RG. That is, in the present embodiment, the resistance of ink IK that electrically connects electrode bars BT and BK is referred to as ink resistor RG.

[0044] <<3. Reference Example>> Hereinafter, while referring to FIG. 6, the outline of the inkjet printer according to the reference example will be described. The inkjet printer according to the reference example is different from the inkjet printer 100 according to the present embodiment in that it includes an ink storage device 1W instead of the ink storage device 1.

[0045] FIG. 6 is a circuit diagram for explaining the configuration of the ink storage device 1W.

[0046] As shown in FIG. 6, the ink storage device 1W is different from the ink storage device 1 according to the present embodiment in that it includes an ink tank TK-W instead of the ink tank TK. The ink tank TK-W is different from the ink tank TK according to the present embodiment in that it does not include a partition wall WL. That is, in the reference example, the electrode bars BT and BK are accommodated in the ink tank TK-W. In the reference example, similar to the present embodiment, the electrode bar BT is provided such that the distance in the Z-axis direction from the end portion of the electrode bar BT in the Z1 direction to the bottom surface TM of the ink tank TK-W is the distance H1, and the electrode bar BK is provided such that the distance in the Z-axis direction from the end portion of the electrode bar BK in the Z1 direction to the bottom surface TM of the ink tank TK-W is the distance H1.

[0047] In the inkjet printer according to the reference example, when the electrode rods BT and BK come into contact with the ink IK stored in the ink tank TK-W, the electrode rods BT and BK are electrically connected via the ink IK stored in the ink tank TK-W. Hereinafter, when the electrode rods BT and BK are electrically connected via the ink IK stored in the ink tank TK-W, the electrical resistance of the ink IK that electrically connects the electrode rods BT and BK is referred to as the ink resistance RW. Further, hereinafter, the output signal Vout output from the ink amount detection circuit 2 provided in the ink storage device 1W is referred to as the output signal Vout-W.

[0048] <<4. Relationship between Ink Liquid Surface Distance, Ink Resistance, and Output Signal>> FIG. 7 is an explanatory diagram for explaining the resistance value change curve CR according to the present embodiment and the resistance value change curve CRW according to the reference example. Here, the resistance value change curve CR is a curve showing the relationship between the resistance value of the ink resistance RG and the ink liquid surface distance SZ in the present embodiment. The resistance value change curve CRW is a curve showing the relationship between the resistance value of the ink resistance RW and the ink liquid surface distance SZ in the reference example. In FIG. 7, the horizontal axis represents the ink liquid surface distance SZ, and the vertical axis represents the resistance value of the ink resistance, so that the relationship between the ink liquid surface distance SZ and the resistance value of the ink resistance is represented as the resistance value change curve CR and the resistance value change curve CRW.

[0049] As described above, in the present embodiment and the reference example, when the ink liquid surface distance SZ is less than the distance H1, the electrode rods BT and BK do not contact the ink IK. That is, when the ink liquid surface distance SZ is less than the distance H1, the electrode rods BT and BK are in a non-electrically connected state. On the other hand, when the ink liquid surface distance SZ is greater than or equal to the distance H1, the electrode rods BT and BK contact the ink IK. That is, when the ink liquid surface distance SZ is greater than or equal to the distance H1, the electrode rods BT and BK are in a state of being electrically connected by the ink IK.

[0050] Therefore, as shown by the resistance value change curve CR in FIG. 7, in this embodiment, when the ink liquid surface distance SZ is greater than or equal to the distance H1, the ink resistance RG has a smaller resistance value compared to the case where the ink liquid surface distance SZ is less than the distance H1. That is, in this embodiment, the resistance value change curve CR has a change region A-R1 where the ink resistance RG changes significantly at the boundary between the case where the ink liquid surface distance SZ is less than the distance H1 and the case where the ink liquid surface distance SZ is greater than or equal to the distance H1.

[0051] Similarly, as shown by the resistance value change curve CRW in FIG. 7, also in the reference example, when the ink liquid surface distance SZ is greater than or equal to the distance H1, the ink resistance RW has a smaller resistance value compared to the case where the ink liquid surface distance SZ is less than the distance H1. That is, the resistance value change curve CRW according to the reference example also has a change region A-R1 where the ink resistance RW changes significantly at the boundary between the case where the ink liquid surface distance SZ is less than the distance H1 and the case where the ink liquid surface distance SZ is greater than or equal to the distance H1, similar to the resistance value change curve CR according to this embodiment.

[0052] Further, in this embodiment, when the ink liquid surface distance SZ is greater than or equal to the distance H1 and less than or equal to the distance H2, the electrical resistance of the ink IK that electrically connects the electrode rod BT and the electrode rod BK is maintained at substantially the same resistance value as the resistance value of the ink resistance RT1. That is, as shown by the resistance value change curve CR in FIG. 7, in this embodiment, when the ink liquid surface distance SZ is greater than or equal to the distance H1 and less than or equal to the distance H2, the ink resistance RG is maintained at substantially the same resistance value. Here, "substantially the same" is a concept that includes not only the case of being completely identical but also the case where it can be regarded as identical considering errors. Specifically, in this specification, "substantially the same" is a concept that includes the case where it can be regarded as identical considering an error of about 10%.

[0053] On the other hand, in the reference example, when the ink liquid surface distance SZ is equal to or greater than the distance H1, as the ink liquid surface distance SZ increases and the cross-sectional area of the ink IK that electrically connects the electrode rod BT and the electrode rod BK increases, the resistance value of the ink resistance RW decreases. Therefore, as shown by the resistance value change curve CRW in FIG. 7, in the reference example, when the ink liquid surface distance SZ is equal to or greater than the distance H1, as the ink liquid surface distance SZ increases, the resistance value of the ink resistance RW decreases.

[0054] Also, in the present embodiment, when the ink liquid surface distance SZ is longer than the distance H2, the electrode rod BT and the electrode rod BK are electrically connected by the ink IK of the ink resistance RT2 existing in the upper opening OP2 in addition to the ink IK of the ink resistance RT1 existing in the lower opening OP1. Then, the resistance value of the combined resistance of the ink resistance RT1 and the ink resistance RT2 when the ink resistance RT1 and the ink resistance RT2 are connected in parallel is smaller than the resistance value of the ink resistance RT1 alone. Therefore, as shown by the resistance value change curve CR in FIG. 7, in the present embodiment, when the ink liquid surface distance SZ is longer than the distance H2, compared with the case where the ink liquid surface distance SZ is equal to or less than the distance H2, the ink resistance RG has a smaller resistance value. That is, in the present embodiment, the resistance value change curve CR has a change region A-R2 where the ink resistance RG changes greatly at the boundary between the case where the ink liquid surface distance SZ is equal to or less than the distance H2 and the case where the ink liquid surface distance SZ is longer than the distance H2.

[0055] On the other hand, in the reference example, the partition wall WL is not provided in the ink tank TK-W. Therefore, as shown in FIG. 7, the resistance value change curve CRW according to the reference example does not have the change region A-R2.

[0056] And in this embodiment, when the ink liquid surface distance SZ is longer than the distance H2, as the ink liquid surface distance SZ becomes longer and the cross-sectional area of the ink IK that electrically connects the electrode rod BT and the electrode rod BK becomes larger, the resistance value of the ink resistance RG becomes smaller. For this reason, as shown by the resistance value change curve CR in FIG. 7, in this embodiment, when the ink liquid surface distance SZ is longer than the distance H2, as the ink liquid surface distance SZ becomes longer, the resistance value of the ink resistance RG becomes smaller.

[0057] Thus, both the resistance value change curve CR according to this embodiment and the resistance value change curve CRW according to the reference example have the change region A-R1. On the other hand, the resistance value change curve CR according to this embodiment has the change region A-R2, while the resistance value change curve CRW according to the reference example does not have the change region A-R2, and has a smooth shape in which the ink resistance RW continuously decreases as the ink liquid surface distance SZ becomes longer.

[0058] FIG. 8 is an explanatory diagram for explaining the potential change curve CV according to this embodiment and the potential change curve CVW according to the reference example. Here, the potential change curve CV is a curve showing the relationship between the output signal Vout output from the ink amount detection circuit 2 in this embodiment and the ink liquid surface distance SZ. The potential change curve CVW is a curve showing the relationship between the output signal Vout-W output from the ink amount detection circuit 2 in the reference example and the ink liquid surface distance SZ. In FIG. 8, the horizontal axis represents the ink liquid surface distance SZ, and the vertical axis represents the potential of the output signal Vout, so that the relationship between the ink liquid surface distance SZ and the potential of the output signal Vout is represented as the potential change curve CV and the potential change curve CVW.

[0059] As described above, the potential of the output signal Vout, that is, the potential of the node NK, is determined based on the resistance value of the ink resistance RG. Specifically, in this embodiment, as an example, it is assumed that when the resistance value of the ink resistance RG is large, the potential of the output signal Vout is higher than when it is small.

[0060] As described above, the resistance value change curve CR has a change region A-R1. Therefore, as shown in FIG. 8, the potential change curve CV also has a change region A-V1, which is a region where the potential of the output signal Vout changes significantly at the boundary between the case where the ink liquid surface distance SZ is less than the distance H1 and the case where the ink liquid surface distance SZ is greater than or equal to the distance H1. Also, as described above, the resistance value change curve CRW also has a change region A-R1. Therefore, as shown in FIG. 8, the potential change curve CVW also has a change region A-V1, which is a region where the potential of the output signal Vout-W changes significantly at the boundary between the case where the ink liquid surface distance SZ is less than the distance H1 and the case where the ink liquid surface distance SZ is greater than or equal to the distance H1. Also, as described above, the resistance value change curve CR has a change region A-R2. Therefore, as shown in FIG. 8, the potential change curve CV also has a change region A-V2, which is a region where the potential of the output signal Vout changes significantly at the boundary between the case where the ink liquid surface distance SZ is less than or equal to the distance H2 and the case where the ink liquid surface distance SZ is longer than the distance H2. Note that, as described above, the resistance value change curve CRW does not have a change region A-R2. Therefore, as shown in FIG. 8, the potential change curve CVW also does not have a change region A-V2.

[0061] Hereinafter, when the temperature of the ink IK in the ink tank TK is the reference temperature t1 and the ink liquid surface distance SZ in the ink tank TK is the distance H1, the potential indicated by the output signal Vout according to the present embodiment is referred to as a threshold potential Vth1. As shown in FIG. 8, when the temperature of the ink IK in the ink tank TK-W is the reference temperature t1 and the ink liquid surface distance SZ in the ink tank TK-W is the distance H1, the potential indicated by the output signal Vout-W in the reference example also becomes the threshold potential Vth1. Further, in the following, when the temperature of the ink IK in the ink tank TK is the reference temperature t1 and the ink liquid surface distance SZ in the ink tank TK is the distance H2, the potential indicated by the output signal Vout in the present embodiment is referred to as the threshold potential Vth2. As shown in FIG. 8, when the temperature of the ink IK in the ink tank TK-W is the reference temperature t1 and the ink liquid surface distance SZ in the ink tank TK-W is the distance H2, the potential indicated by the output signal Vout-W represented by the potential change curve CVW in the reference example is lower than the threshold potential Vth2.

[0062] Here, the reference temperature t1 is, for example, the temperature of the ink IK in the ink tank TK when the inkjet printer 100 is used in a standard usage environment of the inkjet printer 100. Further, the reference temperature t1 may be, for example, the ambient temperature of the inkjet printer 100 when the inkjet printer 100 is used in a standard usage environment of the inkjet printer 100. Further, the reference temperature t1 may be, for example, the temperature of the standard usage environment of the ink IK.

[0063] As described above, in the present embodiment, the control device 8 specifies the remaining amount of the ink IK stored in the ink tank TK based on the output signal Vout.

[0064] Specifically, in the present embodiment, when the potential of the output signal Vout is higher than the threshold potential Vth1, the control device 8 specifies that the remaining amount of the ink IK in the ink tank TK is less than the ink amount corresponding to the distance H1, and when the potential of the output signal Vout is lower than the threshold potential Vth1, the control device 8 specifies that the remaining amount of the ink IK in the ink tank TK is more than the ink amount corresponding to the distance H1. Here, the ink amount corresponding to the distance H1 is an amount based on the minimum amount of ink IK in the ink tank TK. Specifically, the amount based on the minimum amount of ink IK in the ink tank TK may be the minimum ink amount that enables the ejection of ink IK from the liquid ejection head HU by the ink IK supplied from the ink tank TK, or may be an ink amount such that the difference from the minimum ink amount is equal to or less than the first difference amount. Here, the first difference amount may be, for example, an ink amount equal to or less than the ink amount required for the inkjet printer 100 to form an image on a predetermined number of media PP, or may be an ink amount that enables the ejection of ink IK from the liquid ejection head HU a predetermined number of times or less. That is, the ink amount corresponding to the distance H1 may be an ink amount corresponding to a state called the so-called "ink end". In addition, in the present embodiment, the ink amount corresponding to the distance H1 is an example of an "amount based on the minimum amount of liquid in the storage container".

[0065] Further, in the present embodiment, when the potential of the output signal Vout is higher than the threshold potential Vth2, the control device 8 specifies that the remaining amount of ink IK in the ink tank TK is less than the ink amount corresponding to the distance H2, and when the potential of the output signal Vout is lower than the threshold potential Vth2, the control device 8 specifies that the remaining amount of ink IK in the ink tank TK is more than the ink amount corresponding to the distance H2. Here, the ink amount corresponding to the distance H2 is an amount based on the maximum amount of the ink IK in the ink tank TK. Specifically, the amount based on the maximum amount of the ink IK in the ink tank TK may be the maximum ink amount that can be stored in the ink tank TK, or may be an ink amount such that the difference from the maximum ink amount is equal to or less than the second difference amount. Here, the second difference amount may be, for example, the ink amount that can be supplied within a predetermined time when a user of the inkjet printer 100 supplies the ink IK into the ink tank TK through the supply port 12 from a bottle storing the ink IK. Also, for example, the second difference amount may be the minimum amount of the ink IK that can be supplied to the ink tank TK by a bottle storing the ink IK by the user of the inkjet printer 100. That is, the ink amount corresponding to the distance H2 may be an ink amount corresponding to a state called so-called "full". Note that, in the present embodiment, the ink amount corresponding to the distance H2 is an example of an "amount based on the maximum amount of the liquid in the storage container".

[0066] Also, in the reference example, similar to the present embodiment, when the potential of the output signal Vout-W is higher than the threshold potential Vth1, the control device 8 specifies that the remaining amount of the ink IK in the ink tank TK-W is less than the ink amount corresponding to the distance H1, and when the potential of the output signal Vout-W is lower than the threshold potential Vth1, the control device 8 specifies that the remaining amount of the ink IK in the ink tank TK-W is more than the ink amount corresponding to the distance H1. On the other hand, in the reference example, different from the present embodiment, the control device 8 cannot specify whether the remaining amount of the ink IK in the ink tank TK-W is less than the ink amount corresponding to the distance H2 based on the determination result of whether the potential of the output signal Vout-W is higher than the threshold potential Vth2.

[0067] FIG. 9 is an explanatory diagram for explaining the temperature change of the resistance change curve CR accompanying the temperature change of the ink IK in the ink tank TK according to the present embodiment.

[0068] Specifically, in FIG. 9, the resistance value change curve CR when the temperature of the ink IK in the ink tank TK is the reference temperature t1 is represented as the resistance value change curve CR(t1), and the resistance value change curve CR when the temperature of the ink IK in the ink tank TK is a temperature t2 different from the reference temperature t1 is represented as the resistance value change curve CR(t2).

[0069] As shown in FIG. 9, when the temperature of the ink IK in the ink tank TK changes, the resistance value indicated by the resistance value change curve CR also changes. Specifically, when the temperature of the ink IK in the ink tank TK changes from the reference temperature t1 to the temperature t2, the resistance value of the ink resistance RG indicated by the resistance value change curve CR also changes. That is, even when the ink liquid surface distance SZ is the same value, the resistance value of the ink resistance RG indicated by the resistance value change curve CR(t1) and the resistance value of the ink resistance RG indicated by the resistance value change curve CR(t2) are different.

[0070] As described above, the resistance value change curve CR according to the present embodiment has a change region A-R1 in the portion where the ink liquid surface distance SZ is the distance H1. That is, in the change region A-R1 including the portion where the ink liquid surface distance SZ is the distance H1 in the resistance value change curve CR, the resistance value of the ink resistance RG indicated by the resistance value change curve CR changes greatly. Therefore, in the vertical axis direction of the graph shown in FIG. 9, a part of the change region A-R1 of the resistance value change curve CR(t1) and a part of the change region A-R1 of the resistance value change curve CR(t2) overlap.

[0071] Also, as described above, the resistance value change curve CR according to the present embodiment has a change region A-R2 in the portion where the ink liquid surface distance SZ is the distance H2. That is, in the change region A-R2 including the portion where the ink liquid surface distance SZ is the distance H2 in the resistance value change curve CR, the resistance value of the ink resistance RG indicated by the resistance value change curve CR changes greatly. Therefore, in the vertical axis direction of the graph shown in FIG. 9, a part of the change region A-R2 of the resistance value change curve CR(t1) and a part of the change region A-R2 of the resistance value change curve CR(t2) overlap.

[0072] FIG. 10 is an explanatory diagram for explaining the temperature change of the potential change curve CV accompanying the temperature change of the ink IK in the ink tank TK according to the present embodiment.

[0073] Specifically, in FIG. 10, the potential change curve CV when the temperature of the ink IK in the ink tank TK is the reference temperature t1 is represented as the potential change curve CV(t1), and the potential change curve CV when the temperature of the ink IK in the ink tank TK is the temperature t2 is represented as the potential change curve CV(t2).

[0074] As shown in FIG. 10, when the temperature of the ink IK in the ink tank TK changes, the potential indicated by the potential change curve CV also changes. Specifically, when the temperature of the ink IK in the ink tank TK changes from the reference temperature t1 to the temperature t2, the potential of the output signal Vout indicated by the potential change curve CV also changes. That is, even when the ink liquid level distance SZ is the same value, the potential of the output signal Vout indicated by the potential change curve CV(t1) and the potential of the output signal Vout indicated by the potential change curve CV(t2) are different.

[0075] As described above, the potential change curve CV according to the present embodiment has a change region A-V1, which is a region where the potential of the output signal Vout indicated by the potential change curve CV changes greatly at the portion where the ink liquid level distance SZ becomes the distance H1. And the change region A-V1 of the potential change curve CV(t1) intersects the straight line "Vout = Vth1" in the graph shown in FIG. 10. Further, since the change region A-V1 is a region where the potential of the output signal Vout indicated by the potential change curve CV changes greatly, in the vertical axis direction of the graph shown in FIG. 10, a part of the change region A-V1 of the potential change curve CV(t1) and a part of the change region A-V1 of the potential change curve CV(t2) overlap. And if the temperature difference between the reference temperature t1 and the temperature t2 is within a predetermined temperature difference, the change region A-V1 of the potential change curve CV(t2) intersects the straight line "Vout = Vth1" in the graph shown in FIG. 10.

[0076] Here, the predetermined temperature difference may be, for example, the temperature difference between the temperature of the ink IK in the ink tank TK and the reference temperature t1 when the inkjet printer 100 is used in the extreme usage environment of the inkjet printer 100. Further, the predetermined temperature difference may be, for example, the temperature difference between the ambient temperature of the inkjet printer 100 and the reference temperature t1 when the inkjet printer 100 is used in the extreme usage environment of the inkjet printer 100. Further, the predetermined temperature difference may be, for example, the temperature difference between the temperature of the extreme usage environment of the ink IK and the reference temperature t1.

[0077] As described above, the potential change curve CV according to the present embodiment has a change region A-V2, which is a region where the potential of the output signal Vout indicated by the potential change curve CV changes greatly at the portion where the ink liquid surface distance SZ becomes the distance H2. And the change region A-V2 of the potential change curve CV(t1) intersects with the straight line "Vout = Vth2" in the graph shown in FIG. 10. Further, since the change region A-V2 is a region where the potential of the output signal Vout indicated by the potential change curve CV changes greatly, in the vertical axis direction of the graph shown in FIG. 10, a part of the change region A-V2 of the potential change curve CV(t1) and a part of the change region A-V2 of the potential change curve CV(t2) overlap. Therefore, if the temperature difference between the reference temperature t1 and the temperature t2 is within the predetermined temperature difference, the change region A-V2 of the potential change curve CV(t2) intersects with the straight line "Vout = Vth2" in the graph shown in FIG. 10.

[0078] Therefore, according to the present embodiment, when the temperature of the ink IK in the ink tank TK is the reference temperature t1 and the temperature t2, based on the fact that the potential of the output signal Vout is higher than the threshold potential Vth1, it is specified that the remaining amount of the ink IK in the ink tank TK is less than the ink amount corresponding to the distance H1, and based on the fact that the potential of the output signal Vout is higher than the threshold potential Vth2, it can be specified that the remaining amount of the ink IK in the ink tank TK is less than the ink amount corresponding to the distance H2. According to the other party's reference example, similar to the present embodiment, when the temperature of the ink IK in the ink tank TK-W is the reference temperature t1 and when it is the temperature t2, based on the fact that the potential of the output signal Vout-W is higher than the threshold potential Vth1, it can be specified that the remaining amount of the ink IK in the ink tank TK is less than the ink amount corresponding to the distance H1. However, according to the reference example, different from the first embodiment, when the temperature of the ink IK in the ink tank TK-W is the reference temperature t1 and when it is the temperature t2, based on the fact that the potential of the output signal Vout-W is higher than the threshold potential Vth2, the remaining amount of the ink IK in the ink tank TK cannot be specified. That is, according to the inkjet printer 100 according to the present embodiment, compared with the inkjet printer according to the reference example, it is possible to accurately detect the remaining amount of the ink IK in the ink tank TK based on the output signal Vout.

[0079] In the present embodiment, it has been exemplified and described that when the resistance value of the ink resistance RG changes due to the temperature change of the ink IK in the ink tank TK, and as a result, the potential of the output signal Vout shown by the potential change curve CV changes. However, the present invention is not limited to such a mode. The present embodiment can be applied to any case where the potential of the output signal Vout shown by the potential change curve CV fluctuates.

[0080] For example, according to the present embodiment, even when the potential of the output signal Vout shown by the potential change curve CV changes due to the deterioration or denaturation of the ink IK in the ink tank TK, compared with the reference example, it is possible to accurately detect the remaining amount of the ink IK in the ink tank TK based on the output signal Vout. Also, according to the present embodiment, even when the potential of the output signal Vout shown by the potential change curve CV changes due to noise being superimposed on the output signal Vout, compared with the reference example, it is possible to accurately detect the remaining amount of the ink IK in the ink tank TK based on the output signal Vout.

[0081] <<5. Conclusion of the embodiment>> As described above, the inkjet printer 100 according to the present embodiment includes an ink tank TK that stores conductive ink IK, an electrode rod BT stored in the ink liquid chamber RM1 of the ink tank TK, an electrode rod BK stored in the ink liquid chamber RM2 of the ink tank TK, a partition wall WL stored in the ink tank TK that separates the ink liquid chamber RM1 and the ink liquid chamber RM2, an ink amount detection circuit 2 that is electrically connected to the electrode rod BT and the electrode rod BK and outputs an output signal Vout according to an electrical signal from the electrode rod BK, and a control device 8 that specifies the remaining amount of the ink IK stored in the ink tank TK based on the output signal Vout. In the Z1 direction of the partition wall WL, a lower opening OP1 that communicates the ink liquid chamber RM1 and the ink liquid chamber RM2 is formed. In the Z2 direction of the partition wall WL, an upper opening OP2 that communicates the ink liquid chamber RM1 and the ink liquid chamber RM2 is formed. When the ink IK stored in the ink tank TK is present in the lower opening OP1 and the upper opening OP2, the electrode rod BT and the electrode rod BK are in contact with the ink IK stored in the ink tank TK.

[0082] That is, in the present embodiment, the electrode rod BT and the electrode rod BK can take any one of three connection states: a first connection state in which the electrode rod BT and the electrode rod BK are not electrically connected by the ink IK in the ink tank TK; a second connection state in which the electrode rod BT and the electrode rod BK are electrically connected by the ink IK present in the lower opening OP1; and a third connection state in which the electrode rod BT and the electrode rod BK are electrically connected by the ink IK present in the lower opening OP1 and the upper opening OP2. Therefore, in the present embodiment, when the remaining amount of the ink IK in the ink tank TK changes, the ink amount detection circuit 2 can greatly change the potential of the output signal Vout at the boundary between the first connection state and the second connection state and at the boundary between the second connection state and the third connection state. Thus, according to the present embodiment, it is possible to accurately detect the remaining amount of the ink IK in the ink tank TK as compared with the conventional mode in which the potential of the output signal Vout changes smoothly even when the remaining amount of the ink IK in the ink tank TK changes.

[0083] Further, in the inkjet printer 100 according to the present embodiment, the cross-sectional area of the lower opening OP1 is smaller than the cross-sectional area of the upper opening OP2.

[0084] Therefore, according to the present embodiment, it is possible to increase the change amount of the output signal Vout at the boundary between the second connection state and the third connection state as compared with the case where the cross-sectional area of the lower opening OP1 is larger than the cross-sectional area of the upper opening OP2. Thus, according to the present embodiment, it is possible to accurately detect the remaining amount of the ink IK in the ink tank TK as compared with the case where the cross-sectional area of the lower opening OP1 is larger than the cross-sectional area of the upper opening OP2.

[0085] Further, in the inkjet printer 100 according to the present embodiment, when the ink IK stored in the ink tank TK is present at the upper opening OP2, the resistance value of the electrical resistance between the electrode rod BT and the electrode rod BK is smaller than the resistance value of the electrical resistance between the electrode rod BT and the electrode rod BK when the ink IK stored in the ink tank TK is not present at the upper opening OP2.

[0086] Further, in the inkjet printer 100 according to the present embodiment, when the ink IK stored in the ink tank TK is present at the lower opening OP1, the resistance value of the electrical resistance between the electrode rod BT and the electrode rod BK is equal to or less than the resistance value of the electrical resistance between the electrode rod BT and the electrode rod BK when the ink IK stored in the ink tank TK is not present at the lower opening OP1.

[0087] Further, in the inkjet printer 100 according to the present embodiment, when the ink IK stored in the ink tank TK is present at the upper opening OP2, the control device 8 may specify the remaining amount of the ink IK stored in the ink tank TK as an amount based on the maximum amount of the ink IK that can be stored in the ink tank TK.

[0088] In this case, when adding the ink IK to the ink tank TK, it becomes possible to confirm in advance the possibility of the ink IK overflowing from the ink tank TK.

[0089] Further, in the inkjet printer 100 according to the present embodiment, when at least one of the electrode rod BT and the electrode rod BK changes from a state where they are electrically connected by the ink IK stored in the ink tank TK to a state where they are not in contact with the ink IK stored in the ink tank TK, the control device 8 may specify the remaining amount of the ink IK stored in the ink tank TK as an amount based on the minimum amount of the ink IK in the ink tank TK.

[0090] In this case, it becomes possible to confirm in advance the depletion of the ink IK in the ink tank TK.

[0091] Also, in the inkjet printer 100 according to the present embodiment, the partition wall WL is characterized by being composed of an insulator.

[0092] Therefore, according to the present embodiment, it becomes possible to accurately detect the remaining amount of the ink IK in the ink tank TK as compared with the mode in which the partition wall WL is formed of a conductive substance.

[0093] Also, in the inkjet printer 100 according to the present embodiment, the ink tank TK is characterized by including a supply port 12 for supplying the ink IK to the internal space for the ink tank TK to accommodate the ink IK.

[0094] <<B. Modified Example>> Each of the embodiments exemplified above can be variously modified. Specific modified modes are exemplified below. Two or more modes arbitrarily selected from the following examples can be appropriately combined within a range not conflicting with each other.

[0095] <<B.1. Modified Example 1>> In the above-described present embodiment, the case where the ink storage device 1 includes the output circuit 20 has been exemplified and described, but the present invention is not limited to such a mode. The ink storage device 1 may be any device that includes an output circuit 20 capable of detecting the remaining amount of the ink IK stored in the ink tank TK based on an electrical signal from one or a plurality of electrode rods provided in the ink tank TK.

[0096] FIG. 11 is a circuit diagram showing an example of the configuration of an ink storage device 1Q included in an inkjet printer according to Modification 1. Note that the inkjet printer according to Modification 1 is different from the inkjet printer 100 according to the embodiment in that it includes an ink storage device 1Q instead of the ink storage device 1. Further, the ink storage device 1Q is different from the ink storage device 1 according to the embodiment in that it includes an ink amount detection circuit 2Q instead of the ink amount detection circuit 2. That is, the ink storage device 1Q includes an ink amount detection circuit 2Q and an ink tank TK.

[0097] As shown in FIG. 11, the ink amount detection circuit 2Q includes an input terminal TnN, a detection terminal TnK, a reference potential connection terminal TnT, an output terminal TnS, a capacitor CQ1, and an output circuit 20Q having a node NK.

[0098] An input signal Vin is input to the input terminal TnN. The detection terminal TnK is electrically connected to the electrode rod BK via the detection wiring LK. The reference potential connection terminal TnT is electrically connected to the electrode rod BT via the reference potential connection wiring LT. The output terminal TnS outputs an output signal Vout. One of the two electrodes of the capacitor CQ1 is electrically connected to the reference potential connection terminal TnT, and the other electrode is electrically connected to a wiring set to the ground potential.

[0099] The output circuit 20Q includes a node NK, a node NQ1, a node NQ2, a node NQ3, an input resistor RN, a resistor RQ1, a resistor RQ2, a capacitor CQ2, and a switch SWQ.

[0100] The node NK is electrically connected to the detection terminal TnK and also electrically connected to one end of the input resistor RN. The node NQ1 is electrically connected to the other end of the input resistor RN and also electrically connected to the input terminal TnN, and the input signal Vin is supplied via the input terminal TnN.

[0101] Switch SWQ has two input terminals, one output terminal, and one control terminal. Of the two input terminals of switch SWQ, one input terminal is electrically connected to node NK, and the other input terminal is electrically connected to one end of resistor RQ1. The output terminal of switch SWQ is electrically connected to node NQ2. An input signal Vin is supplied to the control terminal of switch SWQ via node NQ1.

[0102] In this modification, the input signal Vin is a signal set to either a high level or a low level signal level. And in this modification, when the input signal Vin supplied to switch SWQ is at a low level, switch SWQ electrically connects the output terminal of switch SWQ and one of the two input terminals of switch SWQ. That is, in this modification, when the input signal Vin supplied to switch SWQ is at a low level, node NK and node NQ2 are electrically connected. Also, in this modification, when the input signal Vin supplied to switch SWQ is at a high level, switch SWQ electrically connects the output terminal of switch SWQ and the other of the two input terminals of switch SWQ. That is, in this modification, when the input signal Vin supplied to switch SWQ is at a high level, one end of resistor RQ1 and node NQ2 are electrically connected.

[0103] One end of resistor RQ1 is electrically connected to the other of the two input terminals of switch SWQ, and the other end is electrically connected to a wiring set to ground potential. One end of resistor RQ2 is electrically connected to node NQ2, and the other end is electrically connected to node NQ3. Of the two electrodes of capacitor CQ2, one electrode is electrically connected to node NQ3, and the other electrode is electrically connected to a wiring set to ground potential. Note that resistor RQ2 and capacitor CQ2 function as a low-pass filter. The output terminal TnS is electrically connected to the node NQ3 and outputs an output signal Vout indicating the potential of the node NQ3.

[0104] FIG. 12 is a timing chart for explaining various signals flowing through the ink amount detection circuit 2Q.

[0105] As shown in FIG. 12, in this modification, it is assumed that the operation period of the ink amount detection circuit 2Q is divided into a plurality of unit periods TQ. And in this modification, it is assumed that each unit period TQ is divided into a control period TP1 and a control period TP2.

[0106] The input signal Vin is set to a high level in the control period TP1 of the unit period TQ and set to a low level in the control period TP2 of the unit period TQ.

[0107] The signal VQK is a signal indicating the potential of the node NK. Hereinafter, when the ink IK stored in the ink tank TK is less than the ink amount corresponding to the distance H1, that is, when the ink IK in the ink tank TK is depleted, the signal VQK is referred to as the signal VQK-E. Also, when the ink IK stored in the ink tank TK is more than the ink amount corresponding to the distance H2, that is, when the ink IK in the ink tank TK is abundant, the signal VQK is referred to as the signal VQK-F.

[0108] When the ink IK in the ink tank TK is depleted, the electrode rod BT and the electrode rod BK are not electrically connected. Therefore, the signal VQK-E shows a waveform with a shape linked to the input signal Vin. Specifically, the signal VQK-E rises from a low level to a high level with a delay of time TQK-E compared to the timing when the input signal Vin rises from a low level to a high level, and falls from a high level to a low level with a delay of time TQK-E compared to the timing when the input signal Vin falls from a high level to a low level. Here, the time TQK-E is shorter than the time length of the control period TP1 and also shorter than the time length of the control period TP2, and is the time for charging the capacitance parasitic on the detection wiring LK, the electrode rod BK, etc.

[0109] When the ink IK in the ink tank TK is abundant, the electrode rod BT and the electrode rod BK are electrically connected. Therefore, the signal VQK-F shows a waveform with a shape that softens the input signal Vin. Specifically, the signal VQK-F rises from a low level to a high level with a delay of time TQK-F compared to the timing when the input signal Vin rises from a low level to a high level, and falls from a high level to a low level with a delay of time TQK-F compared to the timing when the input signal Vin falls from a high level to a low level. Here, the time TQK-F is longer than the time TQK-E, and is the time for charging the capacitance parasitic on the detection wiring LK, the electrode rod BK, etc., in addition to the capacitance parasitic on the reference potential connection wiring LT, the electrode rod BT, etc., and the capacitance CQ1.

[0110] The signal VQ2 is a signal indicating the potential of the node NQ2. Hereinafter, when the ink IK in the ink tank TK is depleted and the ink liquid level distance SZ in the ink tank TK is less than the distance H1, the signal VQ2 is referred to as the signal VQ2-E. Also, when the ink IK in the ink tank TK is abundant and the ink liquid level distance SZ in the ink tank TK is longer than the distance H2, the signal VQ2 is referred to as the signal VQ2-F.

[0111] As described above, during the control period TP1 when the input signal Vin is at a high level, the switch SWQ electrically connects the node NQ2 and one end of the resistor RQ1. Therefore, during the control period TP1, the signal VQ2 is set to a low level.

[0112] Also, during the control period TP2 when the input signal Vin is at a low level, the switch SWQ electrically connects the node NQ2 and the node NK. Therefore, during the control period TP2, the signal VQ2-E shows a waveform shaped such that it takes time TQK-E to fall from a high level to a low level. Also, during the control period TP2, the signal VQ2-F shows a waveform shaped such that it takes time TQK-F to fall from a high level to a low level.

[0113] The signal VQ3 is a signal indicating the potential of the node NQ3. Hereinafter, when the ink IK in the ink tank TK is depleted and the ink liquid level distance SZ in the ink tank TK is less than the distance H1, the signal VQ3 is referred to as the signal VQ3-E. Also, when the ink IK in the ink tank TK is abundant and the ink liquid level distance SZ in the ink tank TK is longer than the distance H2, the signal VQ3 is referred to as the signal VQ3-F.

[0114] As described above, the resistor RQ2 and the capacitor CQ2 function as a low-pass filter. Therefore, the signal VQ3 becomes a signal with a waveform from which high-frequency components have been removed from the signal VQ2. And as described above, the time TQK-F is longer than the time TQK-E. Therefore, the signal VQ3-F becomes a higher potential than the signal VQ3-E. That is, in this modification example, the ink amount detection circuit 2Q outputs a higher-potential output signal Vout when the ink IK in the ink tank TK is abundant and the ink liquid level distance SZ in the ink tank TK is longer than the distance H2, compared to the case when the ink IK in the ink tank TK is depleted and the ink liquid level distance SZ in the ink tank TK is less than the distance H1.

[0115] <<B.2. Modification Example 2>> In the above-described embodiments and Modification 1, in the ink storage device 1, the case where M ink amount detection circuits 2 corresponding one-to-one to M ink tanks TK[1] to TK[M] are provided has been exemplified and described. However, the present invention is not limited to such an aspect. The ink storage device 1 may be provided with a smaller number of ink amount detection circuits 2 than M.

[0116] For example, the ink storage device 1 may be provided with one ink amount detection circuit 2. In this case, the ink amount detection circuit 2 may, for example, divide the operation period of the ink amount detection circuit 2 into M unit operation periods, and in the m-th unit operation period, detect the remaining amount of the ink IK stored in the ink tank TK[m]. Specifically, the ink amount detection circuit 2 may be configured to switch the ink tank TK[m] connected to the ink amount detection circuit 2 for each unit operation period.

[0117] <<B.3. Modification 3>> In the above-described embodiments, Modification 1, and Modification 2, a serial inkjet printer in which the storage case 921 equipped with the liquid ejection head HU is reciprocated in the main scanning direction MH1 has been exemplified. However, the present invention is not limited to such an aspect. The inkjet printer may be a line-type liquid ejection device including a liquid ejection head HU capable of ejecting the ink IK over the entire width of the medium PP.

[0118] <<B.4. Modification 4>> In the above-described embodiments and Modifications 1 to 3, the liquid ejection device exemplified and described by taking an inkjet printer as an example can be adopted in various devices such as a facsimile device and a copying machine in addition to the devices dedicated to printing. However, the use of the liquid ejection device of the present invention is not limited to printing. For example, a liquid ejection device that ejects a solution of a coloring material is used as a manufacturing device for forming a color filter of a liquid crystal display device. Also, a liquid ejection device that ejects a solution of a conductive material is used as a manufacturing device for forming wirings and electrodes of a wiring board.

Explanation of Reference Numerals

[0119] 1... Ink storage device, 2... Ink quantity detection circuit, 8... Control device, 20... Output circuit, 100... Inkjet printer, BK... Electrode rod, BT... Electrode rod, OP1... Lower opening, OP2... Upper opening, RM1... Ink liquid chamber, RM2... Ink liquid chamber, TK... Ink tank, WL... Partition wall.

Claims

1. A storage container for storing a conductive liquid, A first electrode housed in a first liquid chamber of the storage container, A second electrode housed in a second liquid chamber of the storage container, A partition wall housed in the storage container and partitioning the first liquid chamber and the second liquid chamber, Electrically connected to the first electrode and the second electrode, A detection unit that outputs a detection signal corresponding to an electrical signal from one of the first electrode and the second electrode, An identification unit that identifies the remaining amount of the liquid stored in the storage container based on the detection signal, Comprising, A first opening that communicates the first liquid chamber and the second liquid chamber is formed downward of the partition wall, A second opening that communicates the first liquid chamber and the second liquid chamber is formed upward of the partition wall, When the liquid stored in the storage container is present in the first opening and the second opening, The first electrode and the second electrode are in contact with the liquid stored in the storage container, A liquid discharge device characterized by the above.

2. The cross-sectional area of the first opening is smaller than the cross-sectional area of the second opening, The liquid discharge device according to claim 1, characterized by the above.

3. The resistance value of the electrical resistance between the first electrode and the second electrode when the liquid stored in the storage container is present in the second opening, Is smaller than the resistance value of the electrical resistance between the first electrode and the second electrode when the liquid stored in the storage container is not present in the second opening, The liquid discharge device according to claim 1, characterized by the above.

4. The resistance value of the electrical resistance between the first electrode and the second electrode when the liquid stored in the storage container is present in the first opening, Is equal to or less than the resistance value of the electrical resistance between the first electrode and the second electrode when the liquid stored in the storage container is not present in the first opening, The liquid discharge device according to claim 1, characterized by the above.

5. The identification unit, When the liquid stored in the storage container is present in the second opening, Identifies the remaining amount of the liquid stored in the storage container as an amount based on the maximum amount of the liquid in the storage container, The liquid discharge device according to claim 1, characterized by the above.

6. The identification unit, From the state where the first electrode and the second electrode are in contact with the liquid stored in the storage container, When at least one of the first electrode and the second electrode changes to a state where it is not in contact with the liquid stored in the storage container, Specifying the remaining amount of the liquid stored in the storage container as an amount based on the minimum amount of the liquid in the storage container. The liquid discharge device according to claim 1, characterized in that.

7. The partition wall is made of an insulator. The liquid discharge device according to claim 1, characterized in that.

8. The storage container includes a supply port for supplying liquid to an internal space for the storage container to store liquid. The liquid discharge device according to claim 1, characterized in that.

9. A storage container for storing a conductive liquid; A first electrode housed in a first liquid chamber of the storage container; A second electrode housed in a second liquid chamber of the storage container; A partition wall housed in the storage container and partitioning the first liquid chamber and the second liquid chamber; Electrically connected to the first electrode and the second electrode; A detection unit that outputs a detection signal according to an electrical signal from one of the first electrode and the second electrode; Comprising; A first opening communicating the first liquid chamber and the second liquid chamber is formed downward of the partition wall; A second opening communicating the first liquid chamber and the second liquid chamber is formed upward of the partition wall; When the liquid stored in the storage container is present in the first opening and the second opening; The first electrode and the second electrode are in contact with the liquid stored in the storage container. A liquid storage device, characterized in that.

10. The cross-sectional area of the first opening is smaller than the cross-sectional area of the second opening. The liquid storage device according to claim 9, characterized in that.

11. When the liquid stored in the storage container is present in the second opening, the resistance value of the electrical resistance between the first electrode and the second electrode is: Smaller than the resistance value of the electrical resistance between the first electrode and the second electrode when the liquid stored in the storage container is not present in the second opening. The liquid storage device according to claim 9, characterized in that.

12. When the liquid stored in the storage container is present in the first opening, the resistance value of the electrical resistance between the first electrode and the second electrode is: Equal to or less than the resistance value of the electrical resistance between the first electrode and the second electrode when the liquid stored in the storage container is not present in the first opening. The liquid storage device according to claim 9, characterized in that.

13. The detection unit is: When the liquid stored in the storage container is present in the second opening. Outputting the detection signal for specifying the remaining amount of the liquid stored in the storage container as an amount based on the maximum amount of the liquid in the storage container The liquid storage device according to claim 9, characterized in that

14. The detection unit From the state where the first electrode and the second electrode are in contact with the liquid stored in the storage container When at least one of the first electrode and the second electrode changes to a state where it is not in contact with the liquid stored in the storage container Outputting the detection signal for specifying the remaining amount of the liquid stored in the storage container as an amount based on the minimum amount of the liquid in the storage container The liquid storage device according to claim 9, characterized in that

15. The partition wall is made of an insulator The liquid storage device according to claim 9, characterized in that

16. The storage container includes a supply port for supplying liquid to an internal space for the storage container to store liquid The liquid storage device according to claim 9, characterized in that

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