Liquid spraying device

Abstract

To provide a technology that can determine whether any connection failure occurs in an electrode on a liquid jetting device.SOLUTION: A liquid jetting device 1 includes: an electrode part 37 including a first electrode 35 and a second electrode 36; a determination part 161 capable of determining whether the electrode part has any connection failure and whether liquid is left in a liquid container; a first resistor R1 provided between the first electrode and the second electrode and having a first resistance value; and a second resistor having a second resistance value that varies in accordance with an amount of the liquid between the first electrode and the second electrode.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a liquid ejection apparatus. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is known an ink remaining amount detection device that provides two electrodes on a liquid container, applies a voltage between the electrodes, and detects the amount of ink remaining in the liquid container using the resistance value between the electrodes (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-270410 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, when detecting the resistance between electrodes, even if there is a connection failure in the electrodes, the resistance is about the same as when there is no ink remaining. This makes it difficult to determine whether or not there is a connection failure in the electrodes using the resistance between the electrodes. This problem is not limited to technology that detects the amount of ink remaining in a liquid container, but is common to technology that uses two electrodes to detect the amount of liquid other than ink. [Means for solving the problem]

[0005] (1) According to one aspect of the present disclosure, there is provided a liquid ejection device for ejecting liquid, the liquid ejection device including: an electrode unit provided in a liquid container capable of storing the liquid and having a first electrode and a second electrode; a determination unit capable of determining the presence or absence of a connection failure of the electrode unit and the presence or absence of the liquid in the liquid container; a first resistor provided between the first electrode and the second electrode and having a first resistance value; and a second resistor having a second resistance value that changes depending on the amount of the liquid between the first electrode and the second electrode.

[0006] (2) According to another aspect of the present disclosure, there is provided a liquid ejection device for ejecting liquid, the liquid ejection device including an electrode unit provided in a liquid container capable of containing the liquid and having a first electrode and a second electrode, a determination unit capable of determining the presence or absence of a connection failure of the electrode unit and the presence or absence of the liquid in the liquid container, a first capacitor provided between the first electrode and the second electrode, and a second resistor having a second resistance value that changes depending on the amount of the liquid between the first electrode and the second electrode. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is an external perspective view of a liquid ejecting apparatus according to a first embodiment. [Diagram 2] FIG. 4 is a perspective view showing the liquid container unit with the unit cover removed. [Diagram 3] 3A and 3B are diagrams for further illustrating the liquid ejecting apparatus. [Figure 4] FIG. 4 is a diagram showing an example of a liquid detection mechanism. [Diagram 5] FIG. 5 is an equivalent circuit diagram of the liquid detection mechanism in FIG. [Figure 6] 6 is a timing chart showing an example of the operation of the liquid detection mechanism. [Figure 7] FIG. 13 is a diagram showing a simulation result of detection output at a measurement point. [Figure 8] FIG. 13 is a diagram illustrating a liquid ejecting apparatus according to a second embodiment. [Figure 9] FIG. 13 is a diagram showing a simulation result of detection output at a measurement point. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A. First embodiment: FIG. 1 is an external perspective view of a liquid ejection device 1 of a first embodiment. FIG. 2 is a perspective view showing a liquid container unit 20 with a unit cover 21 removed. FIGS. 1 and 2 are indicated with mutually orthogonal coordinate axes, namely, X-axis, Y-axis, and Z-axis. Similar coordinate axes are indicated in subsequent figures as necessary. In this embodiment, the liquid ejection device 1 is disposed and used on a horizontal plane parallel to the X-axis and Y-axis. The Z-axis direction is a direction along the vertical direction, the +Z-axis direction is a vertically upward direction, and the -Z-axis direction is a vertically downward direction. The surface of the liquid ejection device 1 in the +Y-axis direction is referred to as the front surface, and the surface in the -Y-axis direction is referred to as the rear surface.

[0009] The liquid ejection device 1 is an inkjet printer that ejects ink as a liquid 34 onto a medium 12 such as paper to form an image. The liquid 34 may be a pigment-based ink or a dye-based ink. In this embodiment, the liquid 34 is a pigment-based ink. The liquid ejection device 1 includes a liquid container unit 20, an operation unit 13, a paper discharge unit 11, and a case 14. The case 14 forms part of the outer shell of the liquid ejection device 1. A mechanical unit (not shown) of the liquid ejection device 1 is housed inside the case 14. The mechanical unit is a mechanical part that executes a printing operation in the liquid ejection device 1.

[0010] The liquid container unit 20 includes a unit cover 21 and a unit bottom 22, and is installed outside the case 14. The liquid container unit 20 can accommodate a plurality of liquid containers 30. The liquid container 30 stores liquid 34 to be used for printing, and when the liquid ejecting device 1 prints, the liquid 34 is supplied from the liquid container 30 to the print head 17.

[0011] At least a portion of the liquid container 30 is formed from a transparent material, and the stored liquid 34 can be seen from the outside. The unit cover 21 has a transparent window portion 24 at a position facing the transparent portion of the stored liquid container 30. The user can see the amount of liquid 34 in the liquid container 30 through the window portion 24 from outside the liquid ejection device 1.

[0012] An operation unit 13 and a paper discharge unit 11 are arranged on the front of the liquid ejection device 1. The operation unit 13 is provided with a power button, setting buttons, a display panel, etc. The liquid ejection device 1 has a control unit 16 mounted on a control board 15. The control unit 16 operates the above-mentioned mechanism units based on instructions input from the operation unit 13, and prints on the medium 12 by transporting the medium 12 and driving the print head 17. The printed medium 12 is discharged from the paper discharge unit 11. The control board 15 is housed in a case 14.

[0013] 2, the liquid container unit 20 includes a unit bottom 22, a substrate support 27, and a unit cover 21 that surrounds the liquid container 30. The unit bottom 22 and the substrate support 27 are fixed to the liquid ejecting device 1 and installed thereon.

[0014] The liquid container unit 20 can have a plurality of liquid containers 30 mounted side by side facing the unit bottom 22. In this embodiment, four liquid containers 30 are mounted. The four liquid containers 30 may store liquids 34 of different colors, materials, etc. One of the four liquid containers 30 is larger in size than the others and can store more liquid 34. For example, the larger liquid container 30 can store black liquid 34, which is used frequently, and the other liquid containers 30 can store liquids 34, such as yellow, magenta, and cyan, individually.

[0015] 2, the substrate support portion 27 disposed vertically above the unit bottom portion 22 is disposed so as to come into contact with the liquid container 30 when the liquid container 30 is mounted side by side in the liquid container unit 20. Therefore, the liquid container 30 is mounted in the liquid container unit 20 sandwiched between the unit bottom portion 22 and the substrate support portion 27.

[0016] Furthermore, the liquid container 30 is fixed to the substrate support portion 27 by screws 28. The substrate support portion 27 includes a circuit board 26 on which circuits including an AC generating circuit 40, which will be described later, are mounted. When the liquid container 30 is fixed to the substrate support portion 27, the liquid container 30 is also fixed to the circuit board 26. A signal wiring FFC (Flexible Flat Cable) 19 is connected to the circuit board 26, and the circuit mounted on the circuit board 26 and the circuit mounted on the control board 15 of the liquid ejection device 1 are electrically connected. The liquid container 30 comes into contact with the substrate support portion 27 and the circuit board 26 in an area away from an injection port 32 provided in the liquid container 30.

[0017] FIG. 3 is a diagram for further explaining the liquid ejection device 1. The configuration of the liquid container 30 will be mainly described with reference to FIG. 2 and FIG. 3. As shown in FIG. 3, the liquid container 30 is a hollow container, and can store the liquid 34 in the liquid storage chamber 301, which is a hollow portion. The liquid container 30 also has an inlet 32 ​​that can inject the liquid 34 on the vertically upward surface. When the remaining amount of the liquid 34 is low, the liquid container 30 can be refilled with the liquid 34 through the inlet 32. A cap member (not shown) is usually attached airtight to the opening of the inlet 32. A user of the liquid ejection device 1 can replenish the liquid 34 in the liquid container 30 through the inlet 32 ​​by removing the cap member.

[0018] Each liquid container 30 is formed with an outer wall that is at least partially transparent. In this embodiment, a portion of the outer wall in the X-axis direction is transparent. This outer wall surface is provided with a mark 31 shown in FIG. 2 that serves as an indication of the remaining amount. The user can grasp the remaining amount by looking at the mark 31.

[0019] As shown in FIG. 3, the liquid container 30 includes a liquid supply unit 33, an electrode unit 37, and a first resistor R1. The liquid supply unit 33 sends the liquid 34 contained in the liquid container 30 to the print head 17. The electrode unit 37 is used to determine the remaining amount of liquid in the liquid container 30. The electrode unit 37 has a first electrode 35 and a second electrode 36. When the liquid container 30 is sandwiched between the unit bottom 22 and the substrate support unit 27 and attached to the liquid container unit 20, the first electrode 35 and the second electrode 36 protruding outside the liquid container 30 are arranged to contact the circuit board 26 arranged on the substrate support unit 27.

[0020] The first electrode 35 and the second electrode 36 are rod-shaped and extend from the outside of the liquid container 30 to the liquid storage chamber 301. The first electrode 35 and the second electrode 36 are formed of a conductive member, in this embodiment, stainless steel. The length of the first electrode 35 is shorter than the length of the second electrode 36. The second electrode 36 extends closer to the bottom of the liquid storage chamber 301 than the first electrode 35. As a result, when the liquid storage chamber 301 is filled with at least the liquid 34 to the extent that it fills the liquid storage chamber 301, both the first electrode 35 and the second electrode 36 are immersed in the liquid 34. After that, when printing is performed and the liquid 34 is consumed and the amount of liquid decreases, the first electrode 35 is exposed to the outside of the liquid 34, and only the second electrode 36 is immersed in the liquid 34.

[0021] As described above, the liquid container 30 is sandwiched between the unit bottom 22 and the substrate support portion 27 and attached to the liquid container unit 20. The circuit board 26 is disposed on the substrate support portion 27 at a position facing and contacting the first electrode 35 and the second electrode 36 of the liquid container 30. The circuit board 26 has a first terminal 38 and a second terminal 39 formed at positions facing the first electrode 35 and the second electrode 36. As a result, when the liquid container 30 is attached to the liquid container unit 20, the first electrode 35 and the first terminal 38 come into contact with each other and are electrically connected, and the second electrode 36 and the second terminal 39 come into contact with each other and are electrically connected.

[0022] As shown in FIG. 2, the first electrode 35 is crimped to the first terminal 38, and the second electrode 36 is crimped to the second terminal 39 by fixing the substrate support portion 27 and the liquid container 30 with the screw 28. Therefore, the electrodes 35, 36 and the terminals 38, 39 are reliably electrically connected. Furthermore, the circuit mounted on the circuit substrate 26 and the circuit mounted on the control substrate 15 of the liquid ejection device 1 are mutually connected via the signal wiring FFC 19. The circuit mounted on the control substrate 15 includes the control portion 16, so that the circuit on the circuit substrate 26 can communicate with the control portion 16. The electrical connection between the first electrode 35 and the second electrode 36 and the circuit substrate 26 is not limited to the above. For example, the first electrode 35 and the second electrode 36 may be electrically connected to the circuit substrate 26 using a signal line and a connector. Specifically, one end of the first signal line is attached to the first electrode 35 by soldering or the like, and the other end of the first signal line is attached to the connector. Also, one end of the second signal line is attached to the second electrode 36 by soldering or the like, and the other end of the second signal line is attached to the connector. The connector is connected to the connection portion of the circuit board 26, so that the first electrode 35 and the second electrode 36 are electrically connected to the circuit board 26.

[0023] The first resistor R1 is provided between the first electrode 35 and the second electrode 36 in the electric circuit, and has a first resistance value RV1. The first resistor R1 is electrically connected to the first electrode 35 and the second electrode 36. Specifically, in this embodiment, one end of the first resistor R1 is connected to a portion of the first electrode 35 located outside the liquid storage chamber 301, and the other end of the first resistor R1 is connected to a portion of the second electrode 36 located outside the liquid storage chamber 301, so that the first resistor R1 is provided between the first electrode 35 and the second electrode 36.

[0024] The liquid 34 in the liquid storage chamber 301 functions as a second resistor R2. The liquid 34 is conductive and has a second resistance value RV2 that changes depending on the amount between the first electrode 35 and the second electrode 36. Therefore, when both the first electrode 35 and the second electrode 36 are immersed in the liquid 34, the first electrode 35 and the second electrode 36 are electrically connected via the liquid 34.

[0025] The first resistor R1 and the second resistor R2 are resistors connected in parallel to the first electrode 35 and the second electrode 36. The first resistance value RV1 is greater than the maximum value of the second resistance value RV2. In this embodiment, the first resistance value RV1 is 50 kΩ.

[0026] Control unit 16 has a determination unit 161 capable of determining whether or not there is a connection failure caused by a break in electrode unit 37 or the like, and whether or not there is liquid in liquid holder 30.

[0027] The liquid supply unit 33 is provided at a location corresponding to the lower part of the liquid container 30 when the liquid container 30 is in an attached state for use. Liquid 34 injected into the liquid container 30 from the inlet 32 ​​is stored in the liquid storage chamber 301 and is sent to the outside from the liquid supply unit 33. Meanwhile, a tube 18 is fixedly disposed in the liquid ejection device 1 as a liquid transport path. One end of the tube 18 is connected to the liquid supply unit 33, and the other end of the tube 18 is connected to the print head 17. As a result, the liquid 34 in the liquid container 30 is transported via the tube 18 to the print head 17 and used for printing.

[0028] The liquid container unit 20 is configured such that the liquid supply portion 33 is joined to the tube 18 when the liquid container 30 is attached.

[0029] As described above, in the liquid container 30, the liquid supply unit 33 is attached to the tube 18, and the first electrode 35 and the second electrode 36 are electrically connected to the first terminal 38 and the second terminal 39 on the circuit board 26. This makes the liquid 34 stored in the liquid storage chamber 301 of the liquid container 30 available for use in the liquid ejection device 1.

[0030] Next, the liquid detection mechanism 60 will be described with reference to Figs. 4 to 6. Fig. 4 is a diagram showing an example of the liquid detection mechanism 60. Fig. 5 is an equivalent circuit diagram of the liquid detection mechanism 60 of Fig. 4. Fig. 6 is a timing chart showing an example of the operation of the liquid detection mechanism 60. In Fig. 4, VDD indicates the potential on the high potential side of the power supply that operates the liquid detection mechanism 60. VSS indicates the potential on the low potential side of the power supply, and is ground, which is the reference potential. Similar symbols are used in the subsequent drawings.

[0031] 4, the liquid detection mechanism 60 includes an AC generating circuit 40, a detection output generating section 55, and a determination section 161. The AC generating circuit 40 has the following elements. a) Electrode section 37 including first electrode 35 and second electrode 36 b) A periodic signal generating unit 41 that generates a predetermined periodic signal c) p-channel FET 43 as a predetermined potential supply unit d) A third resistor R3, one end of which is connected to the first electrode 35. e) a first terminal 38 connecting the first electrode 35 and the third resistor R3 f) The fourth resistor R4 constituting the reference potential supply section g) a capacitor Ct connected between the second electrode 36 and a reference potential h) a second terminal 39 connecting the second electrode 36 and the capacitor Ct i) a first resistor R1 connected to the first electrode 35 and the second electrode 36

[0032] The detection output generating unit 55 also includes the following elements: j) an analog switch 53 with a control terminal S; k) Resistor R54 and capacitor C54 which form the integrator circuit 54.

[0033] The liquid detection mechanism 60 generates a detection voltage V1 in the AC generating circuit 40, and the detection output generating unit 55 shapes the waveform of the detection voltage V1 to output a detection output 57. The determining unit 161 detects the detection output 57 at a measurement point MP, which is a point after the waveform is generated. Here, the detection output 57 is a voltage at the measurement point MP. The measurement point MP is provided between the first resistor R1 and the second resistor R2 and the determining unit 161 on the electric circuit. In detail, the measurement point MP is located between the detection output generating unit 55 and the determining unit 161 on the electric circuit.

[0034] The elements of the AC generating circuit 40 described above are connected as shown in FIG. 4 to form the AC generating circuit 40. Specifically, the source terminal of the p-channel FET 43 is connected to VDD. The gate terminal of the p-channel FET 43 is connected to the PWM output 42, which is the output of the periodic signal generating unit 41. The drain terminal of the p-channel FET 43 is connected to the third resistor R3 and the fourth resistor R4. Here, the connection point of the drain terminal, the third resistor R3, and the fourth resistor R4 is called the second connection point, and the potential of the second connection point is V2. The third resistor R3 has one end connected to the first electrode 35 via the first terminal 38, and the other end connected to the drain terminal. The fourth resistor R4 has one end connected to VSS, and the other end connected to the drain terminal. The second electrode 36 is connected to a capacitor Ct. The capacitor Ct has one end connected to VSS, and the other end connected to the second electrode 36 via the second terminal 39.

[0035] The periodic signal generating unit 41 is configured with a signal generator capable of generating periodic signals at various timings based on the control of the control unit 16 of the liquid ejecting device 1. Here, the AC generating circuit 40 can be configured, for example, with the third resistor R3 having a resistance value of 10 kΩ, the fourth resistor R4 having a resistance value of 1 kΩ, and the capacitor Ct having a capacitance of 1 nF.

[0036] The detection output generating unit 55 transmits the detection voltage V1 generated in the AC generating circuit 40 to the integrating circuit 54 at a specific timing by the analog switch 53, and smooths the detection voltage V1 by the integrating circuit 54. The smoothed output of the integrating circuit 54 becomes the detection output 57 detected by the determining unit 161. As shown in FIG. 4, the control terminal S of the analog switch 53 is connected to the second connection point in the AC generating circuit 40, and the detection voltage V1 is transmitted to the integrating circuit 54 based on the potential V2 of the second connection point. One of the input / output terminals of the analog switch 53 is connected to the first connection point in the AC generating circuit 40. As described above, the first connection point is the connection point between the first electrode 35 and the third resistor R3, and the potential of the first connection point is the detection voltage V1. The other of the input / output terminals of the analog switch 53 is connected to one end of the resistor R54, which is the input of the integrating circuit 54. The other end of the resistor R54 is connected to one end of a capacitor C54, the other end of which is connected to VSS, and the resistor R54 and the capacitor C54 form an integrating circuit 54. The potential at the connection point between the resistor R54 and the capacitor C54 is the output of the integrating circuit 54, which becomes the detection output 57 that is the output of the detection output generating unit 55. Note that the detection output generating unit 55 can be configured, for example, with the resistance value of the resistor R54 being 66 kΩ and the capacitance of the capacitor C54 being 0.01 μF.

[0037] FIG. 6 is a timing chart TC showing an example of the operation of the liquid detection mechanism 60, and also shows the voltage of the detection voltage V1 and the voltage of the detection output 57 based on the timing chart TC. The PWM output 42 shown in FIG. 6(a) and the PWM output 42 shown in FIG. 6(b) both show the output 42 of the periodic signal generating unit 41. The PWM output 42 shown in FIG. 6(b) is a diagram showing a part of the PWM output 42 shown in FIG. 6(a) enlarged in time. Specifically, it is a diagram showing an enlarged view of the range A surrounded by the two-dot chain line. FIG. 6(c) shows the potential V2 of the second connection point that controls the operation of the analog switch 53. FIG. 6(d) shows the detection voltage V1 for the liquid 34 with a dashed line, and the detection voltage V1 when the liquid 34 is not present with a dashed line. FIG. 6(e) shows the output 56 of the analog switch 53. FIG. 6(f) shows the detection output 57.

[0038] The periodic signal generating unit 41 is controlled to start and stop oscillating the periodic signal by a control signal from the control unit 16. During the period in which the periodic signal generating unit 41 receives an instruction to oscillate from the control unit 16, the unit outputs, as the PWM output 42, a signal that periodically repeats a first period T1 at the VSS level and a second period T2 at the VDD level. In FIG. 6(a), the periods from t1 to t2 and from t3 to t4 are periods in which the unit receives an instruction to oscillate from the control unit. Each period is called a periodic signal section. The length of this section is set to a time that allows the detection unit to obtain a detection output 57 for one liquid container to determine information about the ink. For example, the PWM output 42 periodically repeats a first period T1 and a second period T2 with the same duty ratio of 50% during the periodic signal section.

[0039] When the periodic signal generating section receives a signal to stop oscillation from control section 16 during the period from t2 to t3, it stops oscillation and outputs as output 42 a signal at the Vdd level.

[0040] In the AC generating circuit 40 shown in FIG. 4, the p-channel FET 43 is controlled to be turned ON / OFF based on the PWM output 42. Specifically, the p-channel FET 43 is turned ON when the PWM output 42 is in the first period T1, and turned OFF when the PWM output 42 is in the second period T2. As a result, the drain terminal is at VDD in the first period T1, and is in a high impedance state in the second period T2. Therefore, in the first period T1, the first electrode 35 is connected to VDD via the third resistor R3, and is disconnected in the second period T2. In this way, the p-channel FET 43 functions as a predetermined potential supply unit.

[0041] In the first period T1, the fourth resistor R4 is also connected to VDD, so that a current flows from VDD to VSS via the fourth resistor R4. This current increases the current consumption of the AC generating circuit 40, so in order to prevent the increase in current consumption, it is preferable to make the value of the fourth resistor R4 as large as possible.

[0042] As described above, when both the first electrode 35 and the second electrode 36 are immersed in the liquid 34, the electrodes are in a conductive state through the combined resistance of the first resistor R1 and the second resistor R2 generated by the liquid 34. Therefore, in the first period T1, a current flows through the path of VDD, the p-channel FET 43, the third resistor R3, the first terminal 38, the first electrode 35, the liquid 34, the first resistor R1, the second electrode 36, the second terminal 39, the capacitor Ct, and VSS. When a current flows through this path, the capacitor Ct is charged. Therefore, the potential of the capacitor Ct gradually approaches VDD, and as shown in (d) of FIG. 6, the detection voltage V1 gradually approaches VDD in the first period T1.

[0043] Next, in the second period T2, the p-channel FET 43 is turned OFF. Therefore, no current flows from VDD, and the charged capacitor Ct has the highest potential in the circuit system. As a result, a current flows through the capacitor Ct, the second terminal 39, the second electrode 36, the liquid 34, the first resistor R1, the first electrode 35, the first terminal 38, the third resistor R3, the fourth resistor R4, and VSS. As a result, in the second period T2, the charge stored in the capacitor Ct in the first period T1 is discharged. Therefore, the fourth resistor R4 functions as a reference potential supply unit that connects the first electrode 35 to VSS via the third resistor R3. At this time, the potential of the capacitor Ct gradually decreases as it is discharged. Therefore, as shown in (d) of FIG. 6, in the second period T2, the detection voltage V1 gradually approaches VSS.

[0044] As is clear from the above description, the direction of the current flowing through the liquid 34 in the first period T1 is opposite to the direction of the current flowing through the liquid 34 in the second period T2. In other words, an AC current flows through the liquid 34 in a periodic signal section in which the PWM output 42 periodically repeats the first period T1 and the second period T2.

[0045] Next, the operation of the detection output generating unit 55 shown in FIG. 4 will be described. The potential V2 that controls the analog switch 53 changes as shown in FIG. 6(c) based on the PWM output 42 shown in FIG. 6(b). Specifically, when the PWM output 42 is at the VDD level, the p-channel FET 43 is turned OFF, and the potential V2 approaches VSS via the fourth resistor R4. On the other hand, when the PWM output 42 is at the VSS level, the p-channel FET 43 is turned ON, and the potential V2 becomes VDD. The analog switch 53 is configured to turn OFF when the potential V2 exceeds a predetermined threshold and approaches VDD, and to turn ON when the potential V2 falls below the predetermined threshold and approaches VSS. Therefore, during the second period T2 when the potential V2 approaches VSS, the detection voltage V1 is transmitted to the output 56 of the analog switch 53. On the other hand, during the first period T1 when the potential V2 becomes VDD, the transmission of the detection voltage V1 is interrupted, and the output 56 becomes indefinite. FIG. 6(e) shows this state, and specifically shows that the detection voltage V1 shown in FIG. 6(d) appears at the output 56 during the second period T2.

[0046] As described above, the detection voltage V1 is extracted based on the change in the potential V2, and becomes the output 56 of the analog switch 53 shown in FIG. 6(e). The output 56 is then transmitted to the integrating circuit 54 and smoothed to generate the detection output 57. As a result, a stable detection output 57 is generated as shown in FIG. 6(f). Specifically, the voltage of the detection output 57 when there is no liquid in the liquid storage chamber 301 is lower than the minimum voltage of the detection output 57 when there is liquid in the liquid storage chamber 301. The second resistance value RV2 of the liquid 34 changes according to the remaining amount of liquid in the liquid storage chamber 301. As a result, the voltage of the detection output 57 when there is liquid in the liquid storage chamber 301 also changes. Here, "there is no liquid in the liquid storage chamber 301" refers to a state in which the liquid level in the liquid storage chamber 301 has reached a level lower than the first electrode 35.

[0047] Furthermore, as shown by the solid line in (f) of Figure 6, when a poor connection occurs between the first electrode 35 and the second electrode 36 due to a break or the like, causing the circuit to be in an open state, the potential of the detection output 57 will be lower than the potential of the detection output 57 when there is no liquid in the liquid storage chamber 301.

[0048] Next, the behavior of the AC generating circuit 40 will be described in more detail with reference to Fig. 5 and Fig. 6. In Fig. 5, SW is a switch representing the p-channel FET 43. SW53 is a switch representing the analog switch 53.

[0049] FIG. 7 is a diagram showing a simulation result of the detection output 57 at the measurement point MP. The vertical axis of FIG. 7 is voltage, and the horizontal axis is elapsed time. As shown in FIG. 7, the detection output 57, which is the voltage at the measurement point MP, is higher in the case of remaining amount, in which the first electrode 35 and the second electrode 36 are immersed in the liquid 34, than in the case of no remaining amount, in which the liquid level is located below the first electrode 35. In the case of remaining amount, the resistance when the second resistance value RV2 of the liquid 34 is maximum is 36 kΩ. Moreover, the detection output 57, which is the voltage at the measurement point MP, is higher in the case of no remaining amount than in the case of poor connection of the electrode part 37.

[0050] Based on the results of this simulation, a first threshold value Va and a second threshold value Vb are determined in advance. The first threshold value Va is a threshold value for determining the presence or absence of a connection failure of the electrode unit 37. The second threshold value Vb is a threshold value for determining the presence or absence of liquid in the liquid container 30. The second threshold value Vb is larger than the first threshold value Va. The first threshold value Va and the second threshold value Vb are stored, for example, in a memory of the control unit 16. The determination unit 161 determines the presence or absence of a connection failure of the electrode unit 37 by comparing the detection output 57 with the first threshold value Va. Specifically, the determination unit 161 determines that a connection failure has occurred when the detection output 57 is smaller than the first threshold value Va, and determines that a connection failure has not occurred when the detection output 57 is larger than the first threshold value Va. The determination unit 161 also determines the presence or absence of liquid in the liquid container 30 by comparing the detection output 57 with the second threshold value Vb. Specifically, determination unit 161 determines that there is liquid in liquid container 30 when detection output 57 is greater than second threshold value Vb, and determines that there is no liquid in liquid container 30 when detection output 57 is less than second threshold value Vb and greater than first threshold value Va. The determination of the presence or absence of a connection failure is performed, for example, before shipment of liquid ejection device 1 or when liquid 34 is refilled through inlet 32 ​​of liquid container 30. The determination of the presence or absence of liquid is performed at a predetermined timing, for example, at the end of a print job.

[0051] According to the first embodiment, by providing the first resistor R1 between the first electrode 35 and the second electrode 36, the resistance value between the first electrode 35 and the second electrode 36 can be made different between the case where the amount of liquid is reduced to a level below the first electrode 35 and the case where a connection failure of the electrode unit 37 occurs. As a result, the determination unit 161 can determine the presence or absence of a connection failure and the presence or absence of liquid based on the difference in the resistance value between the first electrode 35 and the second electrode 36. Specifically, the detection output 57, which is the voltage of the measurement point MP, also changes as the resistance value between the first electrode 35 and the second electrode 36 changes. As a result, the determination unit 161 can determine the presence or absence of a connection failure of the electrode unit 37 by comparing the voltage of the measurement point MP with the first threshold value Va, and can determine the presence or absence of liquid by comparing the voltage of the measurement point MP with the second threshold value Vb. In addition, when determining the connection failure of the electrode unit 37, there is no need to place any other element, such as an additional dummy resistor, so that the determination time can be shortened. Furthermore, since there is no need to consider the space for arranging other elements, the degree of freedom in designing the liquid ejecting device 1 is improved.

[0052] In the first embodiment, the first resistance value RV1 is greater than the maximum value of the second resistance value RV2. This allows the resistance values ​​RV1, RV2 between the first electrode 35 and the second electrode 36 to be more significantly different when a connection failure occurs in the electrode portion 37 and when the amount of liquid is reduced. This allows the determination unit 161 to accurately determine the presence or absence of a connection failure of the electrode portion 37 and the presence or absence of liquid based on the difference in the resistance values ​​between the first electrode 35 and the second electrode 36.

[0053] Furthermore, according to the first embodiment, liquid container 30 has inlet 32. This allows determination unit 161 to accurately determine the presence or absence of a connection failure and the presence or absence of liquid even when liquid ejection device 1 is used for a long period of time, such as when liquid is refilled through inlet 32.

[0054] B. Second embodiment: Fig. 8 is a diagram showing a liquid ejection device 1a of a second embodiment. The difference between the liquid ejection device 1 shown in Fig. 3 and the liquid ejection device 1a is that the liquid ejection device 1a includes a first capacitor C1 instead of the first resistor R1. Since the other configurations of the liquid ejection device 1a are the same as those of the first embodiment, the same reference numerals are used for the similar configurations and the description thereof will be omitted.

[0055] The first capacitor C1 is provided between the first electrode 35 and the second electrode 36, similar to the first resistor R1 in the first embodiment. The first capacitor C1 is electrically connected to the first electrode 35 and the second electrode 36. The first capacitor C1 and the second resistor R2 formed by the liquid 34 are connected in parallel to the first electrode 35 and the second electrode 36. The capacitance of the first capacitor C1 is, for example, 220 pF. The determination unit 161 detects the detection output 57, which is the voltage at the measurement point MP provided between the second resistor R2 and the first capacitor C1, and the determination unit 161 on the electric circuit.

[0056] 9 is a diagram showing a simulation result of the detection output 57 at the measurement point MP. As shown in FIG. 9, the detection output 57, which is the voltage at the measurement point MP, is higher in the case where there is a remaining amount, in which the first electrode 35 and the second electrode 36 are immersed in the liquid 34, than in the case where there is no remaining amount, in which the liquid level is located below the first electrode 35. In the case where there is a remaining amount, the resistance when the second resistance value RV2 of the liquid 34 is at its maximum value is 36 kΩ. Furthermore, the detection output 57, which is the voltage at the measurement point MP, is higher in the case where there is no remaining amount than in the case where there is a connection failure of the electrode part 37.

[0057] Based on the results of this simulation, a first threshold value Vaa and a second threshold value Vba are determined in advance. The first threshold value Vaa is a threshold value for determining the presence or absence of a connection failure of the electrode unit 37. The second threshold value Vba is a threshold value for determining the presence or absence of liquid in the liquid container 30. The second threshold value Vba is larger than the first threshold value Vaa. The first threshold value Vaa and the second threshold value Vba are stored, for example, in the memory of the control unit 16. The determination unit 161 determines the presence or absence of a connection failure of the electrode unit 37 by comparing the detection output 57 with the first threshold value Vaa. Specifically, the determination unit 161 determines that a connection failure has occurred when the detection output 57 is smaller than the first threshold value Vaa, and determines that a connection failure has not occurred when the detection output 57 is larger than the first threshold value Vaa. The determination unit 161 also determines the presence or absence of liquid in the liquid container 30 by comparing the detection output 57 with the second threshold value Vba. Specifically, when detection output 57 is smaller than second threshold value Vba, determination unit 161 determines that liquid is present in liquid container 30, and when detection output 57 is smaller than second threshold value Vba and greater than first threshold value Vaa, determination that liquid is absent in liquid container 30. The determination of the presence or absence of a connection failure is performed, for example, before shipment of liquid ejection device 1 or when liquid 34 is refilled through inlet 32 ​​of liquid container 30. The determination of the presence or absence of liquid is performed at a predetermined timing, for example, at the end of a print job.

[0058] According to the second embodiment, by providing the first capacitor C1 between the first electrode 35 and the second electrode 36, the resistance value between the first electrode 35 and the second electrode 36 can be made different between the case where the amount of liquid is reduced to a level below the first electrode 35 and the case where a connection failure of the electrode unit 37 occurs. As a result, the determination unit 161 can determine the presence or absence of a connection failure and the presence or absence of liquid based on the difference in the resistance value between the first electrode 35 and the second electrode 36. Specifically, the detection output 57, which is the voltage of the measurement point MP, also changes as the resistance value between the first electrode 35 and the second electrode 36 changes. As a result, the determination unit 161 can determine the presence or absence of a connection failure of the electrode unit 37 by comparing the voltage of the measurement point MP with the first threshold value Va, and can determine the presence or absence of liquid by comparing the voltage of the measurement point MP with the second threshold value Vb. In addition, when determining the connection failure of the electrode unit 37, it is not necessary to place other elements, such as dummy resistors, so that the determination time can be shortened. Also, since there is no need to consider space for arranging other elements, there is increased freedom in designing the liquid ejecting device 1. Furthermore, according to the second embodiment, the liquid container 30 has the injection port 32. This allows the determination unit 161 to accurately determine the presence or absence of a connection failure in the electrode unit 37 and the presence or absence of liquid even when the liquid ejecting device 1a is used for a long period of time, such as when the liquid is refilled through the injection port 32.

[0059] C. Other embodiments: C-1. Alternative embodiment 1: In the above embodiments, the liquid ejecting device 1, 1a equipped with the liquid container 30 that contains ink as the liquid has been described as an example, but the technology disclosed herein can be applied to a liquid container that contains a liquid other than ink, and to a liquid ejecting device equipped with the liquid container. For example, the technology disclosed herein can be applied to the following liquid ejecting devices other than printers. (1) Image recording devices such as facsimile machines (2) A color material jet recording device used in the manufacture of color filters for image display devices such as liquid crystal displays. (3) Electrode material spraying equipment used to form electrodes in organic EL (Electro Luminescence) displays, field emission displays (FEDs), etc. (4) A liquid injection device for injecting a liquid containing a biological organic substance used in the manufacture of biochips. (5) Sample injection device as a precision pipette (6) Lubricating oil injection device (7) Resin liquid injection device (8) A liquid injection device that uses lubricating oil in a pinpoint manner in precision machinery such as watches and cameras (9) A liquid injection device that injects transparent resin liquid, such as ultraviolet curing resin liquid, onto a substrate to form minute hemispherical lenses (optical lenses) used in optical communication elements, etc. (10) A liquid injection device that injects an acidic or alkaline etching liquid to etch a substrate, etc. (11) A liquid ejection device having a liquid ejection head that ejects any other minute amount of liquid droplets.

[0060] C-2. Alternative embodiment 2: In each of the above embodiments, the first resistor R1 and the first capacitor C1 are not limited to the arrangement in each of the above embodiments as long as they are provided between the first electrode 35 and the second electrode 36 on the electric circuit. For example, the first resistor R1 and the first capacitor C1 may be provided on the circuit board 26. Even in this case, the first resistor R1 and the first capacitor C1 and the second resistor R2 formed by the liquid 34 are connected in parallel between the first electrode 35 and the second electrode 36.

[0061] D. Other forms: The present disclosure is not limited to the above-mentioned embodiment, and can be realized in various forms without departing from the spirit of the present disclosure. For example, the present disclosure can be realized in the following aspects. The technical features in the above-mentioned embodiments corresponding to the technical features in each aspect described below can be appropriately replaced or combined in order to solve some or all of the problems of the present disclosure, or to achieve some or all of the effects of the present disclosure. Furthermore, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

[0062] (1) According to one aspect of the present disclosure, a liquid ejection device for ejecting liquid is provided. The liquid ejection device includes an electrode unit provided in a liquid container capable of storing the liquid and having a first electrode and a second electrode, a determination unit capable of determining the presence or absence of a connection failure of the electrode unit and the presence or absence of the liquid in the liquid container, a first resistor provided between the first electrode and the second electrode and having a first resistance value, and a second resistor having a second resistance value that changes depending on the amount of the liquid between the first electrode and the second electrode. According to this aspect, by providing the first resistor between the first electrode and the second electrode, the resistance value between the first electrode and the second electrode can be made different between when the amount of liquid is small and when a connection failure occurs in the electrode unit. This allows the determination unit to determine the presence or absence of a connection failure and the presence or absence of liquid based on the difference in the resistance value between the first electrode and the second electrode.

[0063] (2) In the above embodiment, the first resistance value may be greater than the maximum value of the second resistance value. According to this embodiment, the resistance value between the first electrode and the second electrode can be made to differ more greatly between a case where a connection failure occurs in the electrode portion and a case where the amount of liquid is reduced. This allows the determination unit to accurately determine the presence or absence of a connection failure and the presence or absence of liquid based on the difference in the resistance value between the first electrode and the second electrode.

[0064] (3) In the above embodiment, the determination unit may determine the presence or absence of the connection failure of the electrode unit by comparing a voltage at a measurement point provided between the first resistor and the second resistor and the determination unit with a predetermined first threshold, and may determine the presence or absence of the liquid by comparing the voltage at the measurement point with a predetermined second threshold. According to this embodiment, the presence or absence of the connection failure of the electrode unit can be determined by comparing the voltage at the measurement point with the first threshold, and the presence or absence of the liquid can be determined by comparing the voltage at the measurement point with the second threshold.

[0065] (4) In the above embodiment, the second threshold value may be greater than the first threshold value. According to this embodiment, by setting the second threshold value greater than the first threshold value, it is possible to determine whether there is a connection failure of the electrode portion and whether there is liquid in the liquid container.

[0066] (5) According to another aspect of the present disclosure, there is provided a liquid ejection device that ejects liquid. The liquid ejection device includes an electrode unit provided in a liquid container capable of storing the liquid, the electrode unit having a first electrode and a second electrode, a determination unit capable of determining the presence or absence of a connection failure of the electrode unit and the presence or absence of the liquid in the liquid container, a first capacitor provided between the first electrode and the second electrode, and a second resistor having a second resistance value that varies depending on the amount of the liquid between the first electrode and the second electrode. According to this aspect, by providing the first capacitor between the first electrode and the second electrode, the resistance value between the first electrode and the second electrode can be made different between when the amount of liquid is small and when a connection failure occurs in the electrode unit. This allows the determination unit to determine the presence or absence of a connection failure and the presence or absence of liquid based on the difference in the resistance value between the first electrode and the second electrode.

[0067] (6) In the above embodiment, the determination unit may determine the presence or absence of the connection failure of the electrode unit by comparing a voltage at a measurement point provided between the second resistor and the first capacitor and the determination unit with a predetermined first threshold, and may determine the presence or absence of the liquid by comparing the voltage at the measurement point with a predetermined second threshold. According to this embodiment, the presence or absence of a connection failure of the electrode unit can be determined by comparing the voltage at the measurement point with the first threshold, and the presence or absence of liquid can be determined by comparing the voltage at the measurement point with the second threshold.

[0068] (7) In the above embodiment, the second threshold value may be greater than the first threshold value. According to this embodiment, by setting the second threshold value greater than the first threshold value, it is possible to determine whether there is a connection failure of the electrode portion and whether there is liquid in the liquid container.

[0069] (8) In the above aspect, the liquid container may have an inlet through which the liquid can be poured. According to this aspect, in a liquid ejection device having a liquid container with an inlet, a determination unit can determine the presence or absence of a connection failure and the presence or absence of liquid.

[0070] In addition to the above aspects, the present disclosure can be realized in the form of a manufacturing method for a liquid ejecting device, a method for determining a connection failure and a remaining amount of liquid, a computer program for executing the determination method, and the like. [Explanation of symbols]

[0071] 1,1a...liquid ejection device, 11...paper discharge section, 12...medium, 13...operation section, 14...case, 15...control board, 16...control section, 17...print head, 18...tube, 20...liquid container unit, 21...unit cover, 22...unit bottom, 24...window section, 26...circuit board, 27...board support section, 28...screw, 30...liquid container, 31...mark, 32...inlet, 33...liquid supply section, 34...liquid, 35...first electrode, 36...second electrode, 37...electrode section, 38...first terminal, 39...second terminal, 40...AC generating circuit, 41...periodic signal generating section, 42...PWM output, 53...analog switch, 54...integral Distribution circuit, 55...detection output generating section, 56...output, 57...detection output, 60...liquid detection mechanism, 161...determination section, 301...liquid storage chamber, A...range, C...first capacitor, C1...first capacitor, C54...capacitor, Ct...capacitor, MP...measurement point, R1...first resistor, R2...second resistor, R3...third resistor, R4...fourth resistor, R54...resistance, RV1...first resistance value, RV2...second resistance value, S...control terminal, T1...first period, T2...second period, TC...timing chart, V1...detection voltage, V2...electric potential, Va, Vaa...first threshold value, Vb, Vba...second threshold value

Claims

1. A liquid ejection device that ejects liquid, an electrode portion provided in a liquid container capable of accommodating the liquid and having a first electrode and a second electrode; a determination unit capable of determining whether or not a connection failure due to disconnection of the electrode unit occurs and whether or not the liquid is present in the liquid container; a first resistor provided between the first electrode and the second electrode and having a first resistance value; a second resistor having a second resistance value that varies with the amount of the liquid between the first electrode and the second electrode; the first electrode and the second electrode are each a member extending from an upper side of the liquid container into the liquid container, the second electrode extending to a position closer to a bottom of the liquid container than the first electrode; The determination unit is determining whether or not the connection failure occurs due to the disconnection of the electrode portion by comparing a voltage at a measurement point provided between the first resistor and the second resistor and the determination unit with a predetermined first threshold value; determining the presence or absence of the liquid by comparing the voltage at the measurement point with a second predetermined threshold value; The liquid ejection apparatus, wherein the second threshold value is greater than the first threshold value.

2. The liquid ejection apparatus according to claim 1 , The liquid ejecting device, wherein the first resistance value is greater than a maximum value of the second resistance value in a state in which the first electrode and the second electrode are immersed in the liquid.

3. A liquid ejection device that ejects liquid, an electrode portion provided in a liquid container capable of accommodating the liquid and having a first electrode and a second electrode; a determination unit capable of determining whether or not a connection failure due to disconnection of the electrode unit occurs and whether or not the liquid is present in the liquid container; a first capacitor provided between the first electrode and the second electrode; a second resistor having a second resistance value that varies depending on the amount of the liquid between the first electrode and the second electrode; the first electrode and the second electrode are each a member extending from an upper side of the liquid container into the liquid container, the second electrode extending to a position closer to a bottom of the liquid container than the first electrode; The determination unit is determining whether or not the connection failure occurs due to the disconnection of the electrode portion by comparing a voltage at a measurement point provided between the second resistor and the first capacitor and the determination unit with a predetermined first threshold value; determining the presence or absence of the liquid by comparing the voltage at the measurement point with a second predetermined threshold value; The liquid ejection apparatus, wherein the second threshold value is greater than the first threshold value.

4. The liquid ejection apparatus according to any one of claims 1 to 3, The liquid ejection device, wherein the liquid container has an inlet through which the liquid can be injected.

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