Liquid discharge device and head unit

Abstract

To provide a liquid discharge device that can improve accuracy in discharging liquid.SOLUTION: The liquid discharge device is provided with: a discharging part that discharges liquid; a container that stores the liquid; a flow passage through which the liquid is supplied from the container to the discharging part; a first electrode provided in the container or in the flow passage; and a control part that applies an AC signal having 3 MHz or more to the first electrode to heat the liquid.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a liquid ejection device and a head unit. [Background technology]

[0002] Patent document 1 discloses a technology in which, in an inkjet printer having an ink tank, an AC signal is applied to an input electrode provided on the ink tank, and the amount of ink stored in the ink tank is detected based on a signal output from a detection electrode provided on the ink tank. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-077616 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have conceived the idea of ​​utilizing electrodes provided on a container or the like in which liquid is stored in a liquid ejection device that ejects liquid such as ink, in order to improve the ejection accuracy of the liquid. [Means for solving the problem]

[0005] One aspect of the liquid ejection device according to the present invention is to A discharge unit that discharges liquid; A container for storing the liquid; a flow path for supplying the liquid from the container to the discharge portion; A first electrode provided in the container or the flow path; A control unit that applies an AC signal of 3 MHz or more to the first electrode to heat the liquid; Equipped with.

[0006] One aspect of the head unit according to the present invention is A discharge unit that discharges liquid; A container for storing the liquid; a flow path for supplying the liquid from the container to the discharge portion; A first electrode provided in the container or the flow path; Equipped with An AC signal of 3 MHz or more is applied to the first electrode to heat the liquid. [Brief description of the drawings]

[0007] [Figure 1] 1 is an explanatory diagram illustrating an example of a configuration of a liquid ejection device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view showing an example of a tank unit. [Diagram 3] FIG. 2 is a perspective view illustrating an example of an ink tank. [Figure 4] 11 is a schematic diagram of the ink tank as viewed from the +Y direction. FIG. [Diagram 5] FIG. 2 is a perspective view showing an example of a schematic internal structure of an ink tank. [Figure 6] FIG. 11 is a schematic diagram of the ink tank as viewed from the -Z direction. [Figure 7] 3A and 3B are schematic diagrams of the ink tank as viewed from the -X direction and the +Z direction. [Figure 8] 4 is a cross-sectional view showing an example of a cross section of the ink tank and the flexible printed circuit board taken along line A1-A2 shown in FIG. [Figure 9] 10 is an explanatory diagram for explaining an outline of a method for detecting the amount of ink stored in an ink tank. FIG. [Figure 10] 5 is an explanatory diagram for explaining the relationship between the ink level in an ink tank and a detection signal. FIG. [Figure 11] FIG. 2 is a diagram illustrating an example of the configuration of a portion of a control unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Preferred embodiments of the present invention will be described below with reference to the drawings. The drawings are used for the convenience of explanation. Note that the embodiments described below do not unduly limit the contents of the present invention described in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0009] In the following description, an inkjet printer is taken as an example of a liquid ejection device according to the present invention. However, the liquid ejection device is not limited to an inkjet printer, and may be, for example, a color material ejection device used in manufacturing color filters for liquid crystal displays and the like, an electrode material ejection device used in forming electrodes for organic electroluminescence displays, surface-emitting displays and the like, a bioorganic material ejection device used in manufacturing biochips, etc.

[0010] 1. Embodiment First, the configuration of an inkjet printer 1 according to this embodiment will be described with reference to FIG.

[0011] Fig. 1 is an explanatory diagram illustrating an example of the configuration of an inkjet printer 1 according to an embodiment of the invention. Note that Fig. 1 shows an example of a partial configuration of the inkjet printer 1.

[0012] The inkjet printer 1 ejects ink to form an image on a printing medium P such as printing paper. Specifically, the inkjet printer 1 is supplied with print data indicating an image to be formed by the inkjet printer 1 from a host computer such as a personal computer or digital camera. The inkjet printer 1 then executes a printing process to form an image indicated by the print data supplied from the host computer on the printing medium P. The printing medium P is not limited to printing paper. For example, the printing medium P may be a medium made of any material such as a resin film or fabric. In this embodiment, it is assumed that the inkjet printer 1 is a serial printer. The inkjet printer 1 may have any of a copy function, a scanner function, a facsimile transmission function, and a facsimile reception function in addition to a printing function. In other words, the inkjet printer 1 may correspond to a so-called "multifunction device."

[0013] The inkjet printer 1 has a head unit 6. The head unit 6 includes a tank unit 10, multiple print heads 30, and a carriage 32, all of which are shown in Fig. 2. The tank unit 10 and the multiple print heads 30 are mounted on the carriage 32.

[0014] Fig. 2 is a perspective view showing an example of the tank unit 10. As shown in Fig. 2, the tank unit 10 has a plurality of ink tanks 100 each having a one-to-one correspondence with a plurality of different types of ink INK, and a plurality of flexible printed circuit boards 200 each having a one-to-one correspondence with the plurality of ink tanks 100.

[0015] FIG. 2 illustrates an example in which there are five types of ink. For example, the five types of ink may be cyan, magenta, yellow, and two types of black. In this case, the tank unit 10 has five ink tanks 100 that correspond one-to-one to the five types of ink. Note that the types of ink are not limited to five. In other words, the number of ink tanks 100 that the tank unit 10 has is not limited to five. For example, when there is one type of ink, the tank unit 10 may have one ink tank 100.

[0016] Each ink tank 100 stores a corresponding ink INK among the plurality of inks INK. Also, each flexible printed circuit board 200 is fixed to a corresponding ink tank 100 among the plurality of ink tanks 100. Hereinafter, the flexible printed circuit board is also referred to as FPC (Flexible Printed Circuits). Note that details of the ink tanks 100 and the FPC 200 will be described later with reference to FIG. 3 etc.

[0017] There is a one-to-one correspondence between the multiple ink tanks 100 shown in Fig. 2 and the multiple print heads 30 shown in Fig. 1. The multiple ink tanks 100 are provided above the multiple print heads 30, and a flow path (not shown) that supplies ink INK from the ink tank 100 to the print head 30 is provided between the corresponding ink tank 100 and print head 30.

[0018] As shown in FIG. 1, the inkjet printer 1 has a control unit 4. The control unit 4 is a processor that controls each part of the inkjet printer 1. For example, the control unit 4 has one or more central processing units (CPUs) (not shown). The control unit 4 functions as a control unit that controls the head unit 6 and the like by, for example, operating according to a control program. For example, the control unit 4 transmits control signals to the head unit 6 in accordance with print data supplied from a host computer, and executes a print process that forms an image indicated by the print data on a print medium P.

[0019] All or part of the elements realized by the control unit 4 executing the control program may be realized in hardware using electronic circuits such as a field programmable gate array (FPGA) or an application specific IC (ASIC). Alternatively, all or part of the functions of the control unit 4 may be realized by cooperation between software and hardware. The control program may be stored in a storage device (not shown) included in the control unit 4, or may be transmitted from another device via a network.

[0020] The inkjet printer 1 includes a timing belt 40, a carriage guide shaft 42, a carriage transport mechanism 43, a transport roller 44, a medium transport mechanism 45, and a platen 46. The carriage guide shaft 42 supports the carriage 32 so that it can reciprocate along the main scanning direction SD1. The timing belt 40 is fixed to the carriage 32 and driven by the carriage transport mechanism 43. This allows the carriage transport mechanism 43 to reciprocate the head unit 6 along the carriage guide shaft 42. The transport roller 44 rotates in response to the drive of the medium transport mechanism 45, and transports the printing medium P on the platen 46 in the sub-scanning direction SD2. The printing medium P is located between the platen 46 and the carriage 32.

[0021] Each print head 30 has multiple ejection units 30a that eject ink INK supplied from each ink tank 100 via a flow path. Under the control of the control unit 4, the transport roller 44 transports the print medium P in the sub-scanning direction SD2, while the head unit 6 reciprocates along the main scanning direction SD1 intersecting the sub-scanning direction SD2, causing the ejection units 30a of each print head 30 to eject ink INK. This changes the relative position of the print medium P with respect to each print head 30, allowing the ink INK to land on the entire print medium P, and forms dots on the print medium P according to the print data.

[0022] In order to form dots of a desired size on the printing medium P, it is necessary for the ejection unit 30a to eject an appropriate amount of ink INK. In order for the ejection unit 30a to eject an appropriate amount of ink INK, the viscosity of the ink INK stored in the ink tank 100 needs to be a desired value. The viscosity of the ink INK changes depending on the temperature, and the higher the temperature, the lower the viscosity. Therefore, in order to make the ink INK have an appropriate temperature, the control unit 4 performs a process of heating the ink INK stored in each ink tank 100 during the first period. The first period may be included in the period in which the ejection unit 30a ejects ink INK. In addition, the first period may not be included in the period in which the ejection unit 30a does not eject ink INK. For example, the period in which the ejection unit 30a ejects ink INK may be a printing period in which the control unit 4 executes a printing process, and the period in which the ejection unit 30a does not eject ink INK may be a non-printing period in which the control unit 4 does not execute a printing process. For example, the control unit 4 may perform a process of heating the ink INK stored in each ink tank 100 only during printing.

[0023] Furthermore, when the remaining amount of ink INK stored in each ink tank 100 is small, problems such as dots of a desired size not being formed on the print medium P or printing processing being stopped may occur. Therefore, when the remaining amount of ink INK is small, it is preferable to notify the user of the inkjet printer 1 of the remaining amount of ink INK before starting printing, etc. For this reason, the control unit 4 performs a process of detecting the amount of ink INK stored in each ink tank 100 during the second period. The second period may be included in a period in which the ejection unit 30a does not eject ink INK. Furthermore, the second period may not be included in a period in which the ejection unit 30a ejects ink INK. For example, the control unit 4 may perform a process of detecting the amount of ink INK stored in each ink tank 100 only during a non-printing period in which the ejection unit 30a does not eject ink INK.

[0024] In the following, the structure of the ink tank 100 will be described in detail, and then the ink INK heating process and the ink storage amount detection process performed by the control unit 4 will be described in detail.

[0025] Fig. 3 is a perspective view showing an example of an ink tank 100. In the following, the configuration of the tank unit 10 will be described focusing on one ink tank 100 out of the multiple ink tanks 100 included in the tank unit 10 and an FPC 200 fixed to the ink tank 100. Fig. 3 shows one ink tank 100 out of the multiple ink tanks 100 included in the tank unit 10 and an FPC 200 fixed to the ink tank 100.

[0026] For convenience of explanation, a three-axis Cartesian coordinate system having an X-axis, a Y-axis, and a Z-axis that are mutually orthogonal will be introduced as appropriate below. In addition, in the following, the direction indicated by the X-axis arrow is referred to as the +X direction, and the opposite direction of the +X direction is referred to as the -X direction. In the following, the direction indicated by the Y-axis arrow is referred to as the +Y direction, and the opposite direction of the +Y direction is referred to as the -Y direction. In the following, the +X direction and the -X direction may be referred to as the X direction without any particular distinction, and the +Y direction and the -Y direction may be referred to as the Y direction without any particular distinction. In the following, the +Z direction and the -Z direction may be referred to as the Z direction without any particular distinction. In the following, the +Z direction may be referred to as the upper side, and the -Z direction may be referred to as the lower side. In this embodiment, the -Z direction is assumed to be the direction of gravity. The -Z direction corresponds to the direction in which the ink INK decreases. In addition, hereinafter, viewing an object from a specific direction may be referred to as planar viewing.

[0027] The ink tank 100 has multiple outer walls 120, a discharge section 150 that discharges ink INK from the ink tank 100, a supply port 160 for supplying ink INK to the ink tank 100, an adjustment port 180, and an attachment section 190. The adjustment port 180 is an intake port that takes in air to adjust the pressure inside the ink tank 100. In addition, the attachment section 190 is a mechanism for attaching the ink tank 100 to the inside of the carriage 32.

[0028] The multiple outer walls 120 include outer walls 120a, 120b, 120c, 120d, and 120e. In addition, in order to make the drawing easier to see, the reference numerals of some of the multiple outer walls 120 are omitted in Fig. 3 .

[0029] The material of the multiple outer walls 120 is not particularly limited as long as it is a dielectric material and does not transmit ink INK. The material of the multiple outer walls 120 may be various resin materials such as polyolefin, polycarbonate, and polyester, or various glass materials. The material of the multiple outer walls 120 may be a hard material or a soft material. Alternatively, some parts of the multiple outer walls 120 may be made of a hard material, and the other parts may be made of a soft material.

[0030] As shown in FIG. 3, the outer wall 120a and the outer wall 120b are disposed apart from each other in the Y direction, and constitute side walls of the ink tank 100 that are approximately parallel to the XZ plane. Note that "approximately parallel", "approximately perpendicular" and "approximately right angle" described later are concepts that include errors. "Approximately parallel" only needs to be parallel in design. Furthermore, the outer wall 120c and the outer wall 120d are disposed apart from each other in the X direction, and constitute side walls of the ink tank 100 that are approximately parallel to the YZ plane. The outer wall 120c is disposed between the outer wall 120a and the outer wall 120b, and is connected to a part of the outer wall 120a and a part of the outer wall 120b at the edges of the outer wall 120a and the outer wall 120b in the +X direction. Furthermore, the outer wall 120d is disposed between the outer wall 120a and the outer wall 120b, and is connected to a part of the outer wall 120a and a part of the outer wall 120b at the edges of the outer wall 120a and the outer wall 120b in the -X direction.

[0031] Moreover, the outer wall 120e includes a surface that is approximately parallel to the XY plane, and constitutes the bottom of the ink tank 100. The outer wall 120e is disposed between the outer walls 120a and 120b, and is connected to a part of the outer wall 120a and a part of the outer wall 120b at the edges of the outer walls 120a and 120b in the -Z direction. The outer walls 120a, 120b, 120c, 120d, and 120e form a box that opens in the +Z direction. The opening of the box is closed by the outer walls 120 other than the outer walls 120a, 120b, 120c, 120d, and 120e among the multiple outer walls 120.

[0032] The outer walls 120a and 120b may be provided so as to be inclined at a predetermined angle with respect to the XZ plane. Similarly, the outer walls 120c and 120d may be provided so as to be inclined at a predetermined angle with respect to the YZ plane.

[0033] The outer wall 120a includes a first arrangement portion PP1 where the electrode 210 is to be provided. A portion of the outer wall 120a including a target arrangement portion where the electrode 210 is to be provided and a peripheral portion of the target arrangement portion corresponds to the first arrangement portion PP1. The first arrangement portion PP1 includes a peripheral portion of the target arrangement portion of the electrode 210 so as to include the entire electrode 210 in a plan view from the -Y direction even if the attachment position of the FPC 200 with respect to the outer wall 120a is shifted from a predetermined position due to an attachment error or the like.

[0034] The width WP1x of the first arrangement portion PP1 in the X direction is larger than the width W10x of the electrode 210 in the X direction, and the width WP1z of the first arrangement portion PP1 in the Z direction is larger than the width W10z of the electrode 210 in the Z direction.

[0035] A part of the FPC 200 is attached to the outer surface OF1 of the outer wall 120a. In this embodiment, among the outer surfaces OF1 of the outer wall 120a, the reference numeral of the outer surface OF1 of the first arrangement portion PP1 has a lowercase alphabet "a" added to the end of the reference numeral.

[0036] The FPC 200 has an electrode 210 provided on the outer surface OF1a of the first arrangement portion PP1, a wire 212 connected to the electrode 210 and extending in the X direction, and two shield wires 240 maintained at a constant voltage such as a ground voltage. In FIG. 3, in order to distinguish the two shield wires 240 from each other, the lowercase alphabet "a" or "b" is added to the end of each reference numeral of the two shield wires 240. The shield wire 240a is a shield wire 240 provided in the -Z direction from the electrode 210, and the shield wire 240b is a shield wire 240 provided in the +Z direction from the electrode 210. In order to distinguish the shield wires 240 from the other shield wires 240, the lowercase alphabet is added to the end of each reference numeral of the shield wire 240 shown in FIG. 4 and subsequent figures.

[0037] The electrode 210, the wiring 212, and the shield wiring 240a, 240b are formed of a conductive material. The conductive material may be, for example, a metal material such as gold, silver, copper, aluminum, iron, nickel, cobalt, or an alloy containing one or more types of metal materials. In this embodiment, it is assumed that the electrode 210 and the wiring 212 are integrally formed. In this case, the wiring 212 is directly connected to the electrode 210.

[0038] The electrode 210 is formed such that the width W10z of the electrode 210 in the Z direction is smaller than the width W10x of the electrode 210 in the X direction. For example, the electrode 210 may be formed in a rectangular shape with the X direction as the longitudinal direction. The shape of the electrode 210 is not limited to a rectangular shape. In the present embodiment, the electrode 210 is located between the shield wiring 240a extending in the X direction and the shield wiring 240b extending in the X direction. The electrode 210 includes a portion that overlaps with the center CXa of the outer wall 120a in the X direction in a plan view from the -Y direction.

[0039] In this embodiment, in addition to the electrode 210, a part of the shield wiring 240a and a part of the shield wiring 240b are also provided on the outer surface OF1a of the first arrangement portion PP1. Therefore, the width WP1z of the first arrangement portion PP1 is larger than the width W40ab in the Z direction of the portion of the FPC 200 that includes the electrode 210 and the shield wirings 240a and 240b.

[0040] Next, with reference to FIG. 4, the elements facing the outer wall 120b among the multiple elements of the FPC 200 will be described.

[0041] Fig. 4 is a schematic diagram of the ink tank 100 as viewed from the +Y direction. In Fig. 4, of the multiple elements of the FPC 200, the elements provided on the outer surface OF2 of the outer wall 120b as seen when the ink tank 100 is viewed from the +Y direction will be mainly described.

[0042] The outer wall 120b includes a second arrangement portion PP2 in which two electrodes 220 are provided. In Fig. 4, in order to distinguish the two electrodes 220 from each other, the reference numerals of the two electrodes 220 are suffixed with a lowercase alphabet "a" or "b." The electrode 220a is an electrode 220 provided in the -Z direction from the electrode 220b.

[0043] In this embodiment, it is assumed that the electrodes 220a and 220b are the same size. In addition, in this embodiment, it is assumed that two electrodes 220a and 220b are provided in the second arrangement portion PP2 of the outer wall 120b, but the number of electrodes 220 provided in the second arrangement portion PP2 is not limited to two. For example, the number of electrodes 220 provided in the second arrangement portion PP2 may be one, or three or more.

[0044] The second arrangement portion PP2 corresponds to a portion of the outer wall 120b including a target arrangement portion where the electrodes 220a and 220b are to be provided and a peripheral portion of the target arrangement portion. The second arrangement portion PP2 includes a peripheral portion of the target arrangement portion of the electrode 220 so as to include the entire electrode 220 in a plan view from the +Y direction even if the attachment position of the FPC 200 relative to the outer wall 120b is shifted from a predetermined position due to an attachment error or the like. The entire electrode 220 includes the entire electrode 220a and the entire electrode 220b.

[0045] The X-direction width WP2x of the second arrangement portion PP2 is larger than both the X-direction width W20ax of the electrode 220a and the X-direction width W20bx of the electrode 220b. Also, the Z-direction width WP1z of the second arrangement portion PP2 is larger than the Z-direction width W20ab of the portion of the FPC 200 that includes the electrodes 220a and 220b.

[0046] A part of the FPC 200 is attached to the outer surface OF2 of the outer wall 120b. In this embodiment, among the outer surfaces OF2 of the outer wall 120b, the reference numeral of the outer surface OF2 of the second arrangement portion PP2 has a lowercase alphabet "a" added to the end of the reference numeral.

[0047] The FPC 200 has an electrode 220a and an electrode 220b provided on the outer surface OF2a of the second arrangement portion PP2, a wiring 222a connected to the electrode 220a and extending in the X direction, and a wiring 222b connected to the electrode 220b and extending in the X direction. The FPC 200 further has a shield wiring 240c that is held at a constant voltage such as a ground voltage. The shield wiring 240c is a shield wiring 240 located between the electrode 220a and the electrode 220b. Therefore, a part of the shield wiring 240c is provided on the outer surface OF2a of the second arrangement portion PP2. In this embodiment, a part of the shield wiring 240a and a part of the shield wiring 240b are also provided on the outer surface OF2a of the second arrangement portion PP2.

[0048] The electrode 220a is located between the shield wiring 240a extending in the X-direction and the shield wiring 240c extending in the X-direction, and the electrode 220b is located between the shield wiring 240b extending in the X-direction and the shield wiring 240c extending in the X-direction. The shield wiring 240c is located between the shield wiring 240a and the shield wiring 240b.

[0049] Moreover, the electrode 220a includes a portion overlapping with the center CXb of the outer wall 120b in the X direction in a plan view from the +Y direction. Similarly, the electrode 220b includes a portion overlapping with the center CXb of the outer wall 120b in the X direction in a plan view from the +Y direction. Note that, in this embodiment, the center CXb of the outer wall 120b in the X direction substantially coincides with the center CXa of the outer wall 120a in the X direction. Also, the position of the supply port 160 in the X direction and the position of the electrode 220a in the X direction are different from each other. Similarly, the position of the supply port 160 in the X direction and the position of the electrode 220b in the X direction are different from each other.

[0050] In this manner, in this embodiment, the electrodes 220a and 220b, and a portion of the shield wiring 240a, a portion of the shield wiring 240b, and a portion of the shield wiring 240c are provided on the outer surface OF2a of the second arrangement portion PP2. Therefore, the width WP2z of the second arrangement portion PP2 is larger than the width W40cd in the Z direction of the portion of the FPC 200 that includes the electrodes 220a and 220b and the shield wirings 240a, 240b, and 240c.

[0051] The electrode 220a is formed such that the width W20az of the electrode 220a in the Z direction is smaller than the width W20ax of the electrode 220a in the X direction. Similarly, the electrode 220b is formed such that the width W20bz of the electrode 220b in the Z direction is smaller than the width W20bx of the electrode 220b in the X direction. In this embodiment, the electrodes 220a and 220b are understood to have a rectangular shape with the X direction as the longitudinal direction in a plan view from the +Y direction. Note that the shape of the electrodes 220a and 220b is not limited to a rectangular shape.

[0052] Furthermore, the electrodes 220a and 220b, the wirings 222a and 222b, and the shield wiring 240c are made of the same material as the electrode 210. In this embodiment, it is assumed that the electrode 220a and the wiring 222a are integrally formed, and the electrode 220b and the wiring 222b are integrally formed. In this case, the wiring 222a is directly connected to the electrode 220a, and the wiring 222b is directly connected to the electrode 220b.

[0053] As described above, the ink tank 100 is provided with the electrodes 210, 220a, and 220b. Specifically, the electrodes 210 and 220a are provided at positions that sandwich a part of the ink tank 100. Similarly, the electrodes 210 and 220b are provided at positions that sandwich a part of the ink tank 100. Then, the control unit 4 applies an AC signal for heating the ink INK stored in the ink tank 100 to the electrode 210 during the first period. Also, the control unit 4 applies an AC signal for detecting the amount of ink INK stored in the ink tank 100 to the electrode 210 during the second period, and detects the amount of ink INK stored in the ink tank 100 based on the voltages of the electrodes 220a and 220b. That is, in this embodiment, the electrodes 210, 220a, and 220b are used for both the process of heating the ink INK and the process of detecting the amount of ink INK stored.

[0054] Next, the internal structure of the ink tank 100 will be described with reference to FIG.

[0055] FIG. 5 is a perspective view showing an example of a schematic internal structure of the ink tank 100. As shown in FIG.

[0056] The ink tank 100 has a plurality of partition walls 122, a plurality of support parts 130, and a plurality of auxiliary parts 140 inside. In FIG. 5, in order to distinguish the plurality of support parts 130 from one another, the reference numerals of the plurality of support parts 130 are suffixed with lowercase alphabets "a", "b", or "c". Similarly, the reference numerals of the plurality of auxiliary parts 140 are suffixed with lowercase alphabets "a", "b", "c", "d", or "e". The number of support parts 130 and the number of auxiliary parts 140 are not limited to the example shown in FIG. 5. For example, the number of support parts 130 may be one or two. Alternatively, the number of support parts 130 may be four or more. The plurality of partition walls 122 include, for example, partition walls 122a and 122b.

[0057] The partition wall 122a is disposed away from the outer wall 120d in the -X direction so as to face the outer wall 120d. The partition wall 122a is located closer to the outer wall 120d than the outer wall 120c. Air is taken into the space between the outer wall 120d and the partition wall 122a through the adjustment port 180 to adjust the pressure inside the ink tank 100. Ink INK is stored in a space SP surrounded by the partition wall 122a and the outer walls 120a, 120b, 120c, and 120e.

[0058] The partition wall 122b separates the space SP from a flow path (not shown) for the ink INK supplied from the supply port 160. The partition wall 122b is disposed away from the outer wall 120e in the +Z direction so as to face the outer wall 120e. In this embodiment, the partition wall 122b is located further in the +Z direction than the second arrangement portion PP2 of the outer wall 120b.

[0059] In this manner, the space SP in which the ink INK is stored is defined by the outer walls 120a, 120b, 120c, and 120e and the partition walls 122a and 122b.

[0060] The support portion 130a supports the outer walls 120a and 120b. The support portion 130a includes a plurality of rod portions 132 that support the outer walls 120a and 120b, a plurality of plate portions 134 that support the outer walls 120a and 120b, and an auxiliary support portion 136. In FIG. 5, in order to distinguish the plurality of rod portions 132 from one another, the reference numerals of the plurality of rod portions 132 are suffixed with a lowercase alphabet "a", "b", or "c". Similarly, the reference numerals of the plurality of plate portions 134 are suffixed with a lowercase alphabet "a" or "b".

[0061] Each rod portion 132 is a columnar body extending in the Y direction. In the example shown in Fig. 5, each rod portion 132 is a cylinder, but each rod portion 132 may be a rectangular column. The multiple rod portions 132 are arranged in the Z direction. One end E1 of each rod portion 132 is bonded to the outer wall 120a, and the other end E2 of each rod portion 132 is bonded to the outer wall 120b.

[0062] Moreover, each plate portion 134 includes a plane that is approximately parallel to the YZ plane. That is, each plate portion 134 includes a plane that is approximately perpendicular to the outer wall 120b. Two edges of the plate portion 134a along the Y direction are connected to the outer walls 120a and 120b, respectively, and two edges of the plate portion 134a along the Z direction are connected to the rod portions 132a and 132b, respectively. Two edges of the plate portion 134b along the Y direction are connected to the outer walls 120a and 120b, respectively, and two edges of the plate portion 134b along the Z direction are connected to the rod portions 132b and 132c, respectively.

[0063] The auxiliary support portion 136 is grasped as being substantially in the shape of a right-angled triangle in a plan view from the +Z direction. Of the edges of the auxiliary support portion 136, two edges corresponding to the two sides other than the hypotenuse of the right-angled triangle are connected to the outer wall 120b and the rod portion 132b, respectively. The rod portion 132b is stably fixed to the outer wall 120b by the auxiliary support portion 136.

[0064] The configuration of the support parts 130b and 130c is the same as that of the support part 130a. Like the support part 130a, the support parts 130b and 130c also support the outer walls 120a and 120b. In Fig. 5, the reference numerals of the elements such as the rod part 132 included in the support parts 130b and 130c are omitted, but the elements included in the support parts 130b and 130c are also referred to using the same reference numerals as the elements included in the support part 130a.

[0065] In this embodiment, it is assumed that the support parts 130a and 130b are disposed on two edges of the first arrangement part PP1 along the Z direction. The support parts 130a and 130b extend along the +Y direction from the first arrangement part PP1 toward the second arrangement part PP2, and support the first arrangement part PP1 and the second arrangement part PP2. Note that since the first arrangement part PP1 of the outer wall 120a is not shown in FIG. 5, the positional relationship between the support parts 130a and 130b and the first arrangement part PP1 will be described later in FIG. 6.

[0066] The auxiliary parts 140 are grasped as being substantially right-angled triangular in plan view from the +X direction. Among the edges of the auxiliary part 140a, two edges corresponding to the two sides other than the hypotenuse of the right triangle are connected to the outer walls 120b and 120e, respectively. Similarly to the auxiliary part 140a, the auxiliary parts 140b and 140c also have two edges corresponding to the two sides other than the hypotenuse of the right triangle connected to the outer walls 120b and 120e, respectively. The auxiliary parts 140a, 140b, and 140c stably fix the outer walls 120b and 120e to each other. In addition, among the edges of the auxiliary part 140d, two edges corresponding to the two sides other than the hypotenuse of the right triangle are connected to the outer wall 120b and the partition wall 122b, respectively. In the auxiliary portion 140e, similarly to the auxiliary portion 140d, two edges corresponding to the two sides other than the hypotenuse of the right triangle are connected to the outer wall 120b and the partition wall 122b, respectively. The outer wall 120b and the partition wall 122b are stably fixed to each other by the auxiliary portions 140d and 140e.

[0067] Furthermore, in this embodiment, it is assumed that the support section 130 and the auxiliary section 140 are subjected to a water-repellent treatment, but a part or all of the support section 130 and the auxiliary section 140 do not need to be subjected to the water-repellent treatment.

[0068] The discharge portion 150 is provided with a discharge port Hd that penetrates the discharge portion 150 and the outer wall 120e and discharges the ink INK from the space SP. The discharge port Hd is located near the center of the outer wall 120e in the X direction. The positional relationship between the discharge port Hd and the first arrangement portion PP1 and the second arrangement portion PP2 will be described later with reference to FIG.

[0069] The supply port 160 is open in the +Z direction. An opening Hf of the supply port 160 communicates with the space SP via a flow path (not shown). This allows the ink INK to be supplied from the supply port 160 to the space SP.

[0070] The ink INK stored in the space SP is discharged from the discharge port Hd of the discharge section 150 and is supplied to the discharge section 30a of the print head 30 via a flow path (not shown).

[0071] Next, the positional relationship between the electrodes 210 and 220 and the outlet Hd will be described with reference to FIG.

[0072] Fig. 6 is a schematic diagram of the ink tank 100 as viewed from the -Z direction. Fig. 6 illustrates the positional relationship between the electrodes 210 and 220 and the discharge port Hd. In Fig. 6, the shield wiring 240 and the like are omitted in order to make it easier to understand the positional relationship between the electrodes 210 and 220 and the discharge port Hd. In Fig. 6, the supports 130a and 130b are indicated by dashed lines in order to illustrate the positional relationship between the first arrangement portion PP1 of the outer wall 120a and the second arrangement portion PP2 of the outer wall 120b and the supports 130a and 130b.

[0073] 6, when the outlet Hd is viewed from the -Z direction, the entire outlet Hd is located between the electrodes 210 and 220. This allows the control unit 4 to efficiently heat the ink INK near the outlet Hd in the first period, and detect the amount of stored ink INK near the outlet Hd in the second period.

[0074] When the exhaust outlet Hd is viewed from the -Z direction, the exhaust outlet Hd may include a portion located between the electrode 210 and the electrode 220, and a portion not located between the electrode 210 and the electrode 220. When the exhaust outlet Hd is viewed from the -Z direction, at least a part of the exhaust outlet Hd may be located between the first arrangement portion PP1 of the outer wall 120a and the second arrangement portion PP2 of the outer wall 120b.

[0075] Moreover, when focusing on the position of the discharge port Hd, the discharge port Hd is formed near the center of the outer wall 120e in the X direction. The discharge port Hd is formed so that the center CXs of the space SP of the ink tank 100 in the X direction is located inside the discharge port Hd in a plan view from the -Z direction. In the example shown in Fig. 6, the discharge port Hd is formed so that the center CP of the space SP of the ink tank 100 is located inside the discharge port Hd in a plan view from the -Z direction. As a result, in this embodiment, when the ink tank 100 is used in an inclined state, it is possible to reduce the amount of ink INK that is not discharged from the discharge port Hd and remains in the space SP.

[0076] Furthermore, the width W10x of the electrode 210 in the X direction and the width W20ax of the electrode 220a in the X direction are greater than the width WHx of the discharge port Hd in the X direction. As a result, in this embodiment, even if the ink tank 100 is tilted, the control unit 4 can efficiently heat the ink INK near the discharge port Hd in the first period, and can accurately detect whether the amount of ink INK stored in the ink tank 100 is equal to or greater than a predetermined lower limit in the second period.

[0077] The support parts 130a and 130b are disposed on two edges of the first arrangement part PP1 of the outer wall 120a along the Z direction. The end part E1 of each rod part 132 of the support part 130a is fixed to one of the two edges of the first arrangement part PP1 along the Z direction, and the end part E1 of each rod part 132 of the support part 130b is fixed to the other of the two edges of the first arrangement part PP1 along the Z direction. The end part E2 of each rod part 132 of the support part 130a is fixed to one of the two edges of the second arrangement part PP2 along the Z direction, and the end part E2 of each rod part 132 of the support part 130b is fixed to the other of the two edges of the second arrangement part PP2 along the Z direction.

[0078] In this manner, in the present embodiment, a range of the outer wall 120a including the positions in the X direction of each rod portion 132 of the support portion 130a and each rod portion 132 of the support portion 130b can be regarded as the X direction range of the first arrangement portion PP1. Similarly, in the present embodiment, a range of the outer wall 120b including the positions in the X direction of each rod portion 132 of the support portion 130a and each rod portion 132 of the support portion 130b can be regarded as the X direction range of the second arrangement portion PP2.

[0079] The thickness T1 of the first arrangement portion PP1 of the outer wall 120a is thinner than the thickness T2 of the second arrangement portion PP2 of the outer wall 120b. The thickness T1 of the first arrangement portion PP1 of the outer wall 120a is thinner than the thickness T3 of the outer wall 120d. Furthermore, in this embodiment, it is assumed that the outer wall 120a is formed of a nylon film having a smaller elastic modulus than the outer wall 120b, etc., so the outer wall 120a is more likely to deform than the outer wall 120b, etc. For this reason, in this embodiment, support parts 130a and 130b are provided to support the first arrangement portion PP1 and the second arrangement portion PP2. As a result, in this embodiment, the first arrangement portion PP1 can be suppressed from deforming. In addition, in this embodiment, in addition to the support parts 130a and 130b, the support part 130c is provided to support the portion of the outer wall 120a other than the first arrangement portion PP1 and the portion of the outer wall 120b other than the second arrangement portion PP2, so that the outer wall 120a can be suppressed from deforming.

[0080] Note that the rod portions 132 of the support portion 130a and the rod portions 132 of the support portion 130b may be disposed outside the first arrangement portion PP1 as long as deformation of the first arrangement portion PP1 can be suppressed. Specifically, the rod portions 132 of the support portion 130a may be positioned in the -X direction from the first arrangement portion PP1. Similarly, the rod portions 132 of the support portion 130b may be positioned in the +X direction from the first arrangement portion PP1. Furthermore, the support portion 130 may be provided near the center of the first arrangement portion PP1 in the X direction.

[0081] The plate portion 134 may be formed in a lattice shape having through holes through which the ink INK passes. Alternatively, the plate portion 134 may be omitted. The support portion 130 may have a plurality of pillars extending in the Z direction instead of the plate portion 134. In this case, the support portion 130 may be formed in a lattice shape having openings through which the ink INK passes by a plurality of pillars extending in the Z direction and a plurality of rod portions 132 extending in the Y direction. Alternatively, a triangular or L-shaped support portion that supports the outer walls 120a, 120e may be provided. A plate-shaped support portion that has a surface parallel to the inner surface IF3 of the outer wall 120e and supports the outer walls 120a, 120b may be provided.

[0082] Next, with reference to FIG. 7, an outline of the ink tank 100 as viewed from the -X direction will be described.

[0083] Fig. 7 is a schematic diagram of the ink tank 100 as viewed from the -X direction and as viewed from the +Z direction. In Fig. 7, the plan view shown on the upper side is a schematic diagram of the ink tank 100 as viewed from the -X direction, and the plan view shown on the lower side is a schematic diagram of the ink tank 100 as viewed from the +Z direction. Note that in Fig. 7, electrodes 210 and electrodes 220, etc. are omitted to make the drawing easier to see.

[0084] As shown in the schematic diagram of the ink tank 100 seen from the -X direction, the ink tank 100 has positioning portions PT10 and PT12. The positioning portions PT10 and PT12 are made of the same material as the outer wall 120d and are formed integrally with the outer wall 120d. That is, in this embodiment, the positioning portions PT10 and PT12 are provided on the outer wall 120d, which is a portion formed of a material harder than the first arrangement portion PP1. The positioning portions PT10 and PT12 are formed in a convex shape protruding from the outer wall 120d in the -X direction. Moreover, the positioning portion PT10 is grasped as a rectangular shape in a plan view from the -X direction. Moreover, the positioning portion PT12 is grasped as a triangular shape in a plan view from the -X direction. The positioning portions PT10 and PT12 are provided on the outer wall 120d, and the positioning portion PT10 is located in the +Z direction from the positioning portion PT12.

[0085] The FPC 200 also has a positioning portion PT20 which determines the position of the FPC 200 by connecting to the positioning portion PT10, and a positioning portion PT22 which determines the position of the FPC 200 by connecting to the positioning portion PT12.

[0086] As shown in the schematic diagram of the ink tank 100 as viewed from the -X direction, a notch that opens in the +Z direction and fits with the positioning portion PT10 is formed as the positioning portion PT20 at the +Z direction edge of the two edges of the FPC 200 along the Y direction. That is, the area inside the notch formed as the positioning portion PT20 is understood as being rectangular in plan view from the -X direction. Also, a notch that opens in the -Z direction and fits with the positioning portion PT20 is formed as the positioning portion PT22 at the -Z direction edge of the two edges of the FPC 200 along the Y direction. That is, the area inside the notch formed as the positioning portion PT22 is understood as being triangular in plan view from the -X direction.

[0087] The positioning portions PT20 and PT22 are not limited to notches. For example, a through hole that penetrates the FPC 200 in the X direction and engages with the positioning portion PT10 may be formed as the positioning portion PT20. Similarly, a through hole that penetrates the FPC 200 in the X direction and engages with the positioning portion PT12 may be formed as the positioning portion PT22.

[0088] In this embodiment, when the FPC 200 is attached to the ink tank 100, the positioning portion PT20 of the FPC 200 is connected to the positioning portion PT10 of the ink tank 100, and the positioning portion PT22 of the FPC 200 is connected to the positioning portion PT12 of the ink tank 100. This makes it possible to prevent the position of the FPC 200 relative to the ink tank 100 from shifting from a predetermined position when the FPC 200 is attached to the ink tank 100 in this embodiment.

[0089] Furthermore, in this embodiment, the shape of the positioning portion PT10 is different from the shape of the positioning portion PT12. This makes it possible to reduce the possibility of the positioning portion PT22 being erroneously fitted into the positioning portion PT10, or the possibility of the positioning portion PT20 being erroneously fitted into the positioning portion PT12. This makes it possible to reduce the possibility of the FPC 200 being attached to the ink tank 100 in the wrong orientation.

[0090] The positioning portions PT10 and PT12 may be formed such that one or both of the shape and size of the positioning portion PT10 and the positioning portion PT12 are different. When the size of the positioning portion PT10 is different from the size of the positioning portion PT12, the shape of the positioning portion PT10 and the shape of the positioning portion PT12 may be the same. Even in this case, it is possible to reduce the possibility of the FPC 200 being attached to the ink tank 100 in an incorrect orientation. Below, the positioning portions PT10, PT12, PT20, and PT22 may be collectively referred to as the positioning portions PT.

[0091] The FPC 200 also has a terminal TMt1 electrically connected to the electrode 210, a terminal TMR1 electrically connected to the electrode 220a, and a terminal TMR2 electrically connected to the electrode 220b. The FPC 200 also has a plurality of terminals TMg1 to TMg6 that are held at a constant voltage such as a ground voltage. Hereinafter, the terminals TMg1 to TMg6 may be collectively referred to as terminals TMg. The number of terminals TMg is not limited to six. For example, the number of terminals TMg may be two or more and five or less, or seven or more. Hereinafter, the terminals TMt1, TMR1, TMR2, and TMg may be collectively referred to as terminals TM. The plurality of terminals TMg are formed, for example, from the same material as the electrode 210.

[0092] In this embodiment, it is assumed that the multiple terminals TMg are held at the ground voltage, but the multiple terminals TMg may be held at a constant voltage other than the ground voltage. Alternatively, the multiple terminals TMg may include a terminal TMg held at a first constant voltage such as the ground voltage, and a terminal TMg held at a second constant voltage other than the first constant voltage. Each of the multiple terminals TMg1 to TMg6 is electrically connected to one or more of the multiple shield wirings 240. Note that, when focusing on the multiple shield wirings 240, each of the multiple shield wirings 240 is electrically connected to one or more of the multiple terminals TMg1 to TMg6.

[0093] In this embodiment, in order to reduce interference between two terminals TM among terminals TMt1, TMR1, and TMR2, one or more terminals TMg among the multiple terminals TMg are arranged between the two terminals TM. Interference between two terminals TM occurs when a signal transmitted to one of the two terminals TM is transmitted to the other terminal TM as noise. In this embodiment, in a plan view from the -X direction, a terminal TMg that overlaps with a straight line connecting an arbitrary position in one terminal TM and an arbitrary position in the other terminal TM corresponds to the terminal TMg located between the two terminals TM.

[0094] Among the multiple terminals TMg, terminals TMg1, TMg2, and TMg3 are arranged between terminals TMt1 and TMR1. Terminals TMg3 and TMg6 are arranged between terminals TMR1 and TMR2. Terminals TMg1, TMg2, TMg4, and TMg5 are arranged between terminals TMR2 and TMt1.

[0095] Moreover, the terminal TMt1 contacts a first external contact outside the FPC 200, the terminal TGr1 contacts a second external contact outside the FPC 200, and the terminal TGr2 contacts a third external contact outside the FPC 200. The first external contacts are electrically connected to a power supply circuit 12, which will be described later in Fig. 11. The second external contact is electrically connected to an input terminal IN1 of a selection circuit 13, which will be described later in Fig. 11, and the third external contact is electrically connected to an input terminal IN2 of the selection circuit 13.

[0096] The multiple terminals TMg1 to TMg6 are in contact with multiple constant voltage contacts outside the FPC 200. The multiple constant voltage contacts are held at a constant voltage such as ground voltage. That is, the multiple terminals TMg1 to TMg6 are held at a constant voltage such as ground voltage by being in contact with multiple constant voltage contacts held at a constant voltage such as ground voltage.

[0097] In this embodiment, the external contact CTt1, which will be described later in FIG. 9, corresponds to the first external contact, the external contact CTr1 corresponds to the second external contact, the external contact CTr2 corresponds to the third external contact, and the external contacts CTg1 to CTg6 correspond to the constant voltage contacts. Hereinafter, the external contacts CTt1, CTr1, CTr2, and CTg1 to CTg6 may be collectively referred to as the external contacts CT. The external contact CT is also used as a collective term for the first external contact, the second external contact, the third external contact, and a plurality of constant voltage contacts.

[0098] The connections between the multiple terminals TM and the multiple external contacts CT are realized, for example, by spring contacts. For example, the multiple external contacts CT are provided on an external board that is detachable from the ink tank 100. When the external board is attached to the ink tank 100, a repulsive force of a spring or the like acts on each of the multiple external contacts CT provided on the external board, pushing the external contact CT in the +X direction.

[0099] When attention is paid to the positional relationship between the multiple terminals TM and the positioning portions PT20, PT22, at least a portion of the terminal arrangement area AR including the multiple terminals TM in the FPC200 is located between the positioning portions PT20 and PT22. In the portions of the FPC200 that are close to the positioning portions PT20, PT22, the deviation of the attachment position of the FPC200 with respect to the ink tank 100 is smaller than in the portions of the FPC200 that are far from the positioning portions PT20, PT22.

[0100] In this embodiment, since the multiple terminals TM are disposed near the positioning portions PT20, PT22, it is possible to reduce deviation of the multiple terminals TM from their predetermined positions relative to the ink tank 100. As a result, in this embodiment, it is possible to prevent erroneous connections between the multiple terminals TM and the multiple external contacts CT. Furthermore, in this embodiment, it is possible to reduce deviation of the multiple terminals TM from their predetermined positions relative to the ink tank 100, which improves the stability of the connections between the multiple terminals TM and the multiple external contacts CT.

[0101] As shown in the schematic diagram of the ink tank 100 viewed from the +Z direction, the FPC 200 is folded at the folding portions BP1 and BP2 along the outer circumference of the ink tank 100. When the ink tank 100 is viewed from the +Z direction, the terminals TM are provided on the edge EP1 of the two edges EP1 and EP2 of the ink tank 100, and the supply port 160 is located closer to the edge EP2 than the edge EP1. The two edges EP1 and EP2 of the ink tank 100 are edges that are separated from each other in the X direction among the edges that are grasped when the ink tank 100 is viewed from the +Z direction. Note that when the ink tank 100 is viewed from the +Z direction, the X direction corresponds to the longitudinal direction of the ink tank 100. Hereinafter, the edge of the outer wall 120e among the edge EP1 of the ink tank 100 may be simply referred to as the edge EP1 of the outer wall 120e. Similarly, of the edge portion EP2 of the ink tank 100, the edge portion of the outer wall 120e may be simply referred to as the edge portion EP2 of the outer wall 120e.

[0102] Thus, in this embodiment, the supply port 160 is located closer to the edge portion EP2 than to the edge portion EP1 where the multiple terminals TM are provided. Therefore, in this embodiment, even if the ink INK leaks from the supply port 160 when the ink INK is supplied, it is possible to prevent the leaked ink INK from soiling the vicinity of the multiple terminals TM. If the vicinity of the multiple terminals TM is soiled by the ink INK leaked from the supply port 160, there is a risk that the multiple terminals TM will short-circuit. In this embodiment, it is possible to prevent the vicinity of the multiple terminals TM from being soiled by the ink INK leaked from the supply port 160, and therefore it is possible to prevent the multiple terminals TM from short-circuiting.

[0103] Next, a cross section of the ink tank 100 and the FPC 200 will be described with reference to FIG.

[0104] Fig. 8 is a cross-sectional view showing an example of a cross section of the ink tank 100 and the FPC 200 along the A1-A2 line shown in Fig. 4. In Fig. 8, elements located in the +Z direction from the partition wall 122b, the support portion 130, etc. are omitted in order to make the drawing easier to see.

[0105] The FPC 200 has a non-conductive first cover film layer 201, a conductive first conductor layer 202, a non-conductive base layer 203, a conductive second conductor layer 204, and a non-conductive second cover film layer 205. The base layer 203 is provided between the first cover film layer 201 and the second cover film layer 205. The first conductor layer 202 is provided between the first cover film layer 201 and the base layer 203, and the second conductor layer 204 is provided between the second cover film layer 205 and the base layer 203.

[0106] The first conductive layer 202 includes an electrode 210, electrodes 220a and 220b, and shield wirings 240a, 240b, and 240c. The first conductive layer 202 further includes wirings 212, 222a, and 222b shown in FIGS. 3 and 4. The second conductive layer 204 further includes shield wirings 240d and 240e that are held at a constant voltage such as a ground voltage. The second conductive layer 204 further includes terminals TMt1, TMR1, TMR2, and TMg1 to TMg6 shown in FIG. 7. The shield wirings 240d and 240e are formed of, for example, the same material as the electrode 210.

[0107] The first cover film layer 201 and the second cover film layer 205 are formed of, for example, a polyimide film. The first cover film layer 201 and the second cover film layer 205 may be formed of a material other than a polyimide film.

[0108] The tank unit 10 also has a double-sided tape 260 that adheres the FPC 200 to the ink tank 100. The first cover film layer 201 is provided between the second cover film layer 205 and the ink tank 100, and is adhered to the ink tank 100 by the double-sided tape 260. The double-sided tape 260 includes a base material 264, a first adhesive layer 262 formed on a first surface SF1 of the base material 264, and a second adhesive layer 266 formed on a second surface SF2 of the base material 264 opposite to the first surface SF1.

[0109] The FPC 200 is attached to the ink tank 100 at a position determined by the positioning portions PT10, PT12, PT20, and PT22 shown in FIG. 7 by using a double-sided tape 260. As a result, the electrode 210 included in the FPC 200 is provided on the outer surface OF1a of the first arrangement portion PP1 of the outer wall 120a, and the electrodes 220a and 220b included in the FPC 200 are provided on the outer surface OF2a of the second arrangement portion PP2 of the outer wall 120b. The electrode 210 is disposed at a position where the entire electrode 210 overlaps with the outer surface OF1a of the first arrangement portion PP1 in a plan view from the -Y direction. The electrodes 220a and 220b are disposed at a position where the entire electrode 220a and the entire electrode 220b overlap with the outer surface OF2a of the second arrangement portion PP2 in a plan view from the +Y direction.

[0110] Furthermore, in this embodiment, the FPC 200 is attached to the ink tank 100 such that, in plan view from the +Y direction, the entire electrode 220a and the entire electrode 220b overlap with the electrode 210. The electrodes 220a and 220b are disposed at different positions in the Z direction.

[0111] In the Z direction, electrode 220a is disposed so that the center of electrode 220a is at position H1, and electrode 220b is disposed so that the position of the center of electrode 220b is at position H2. Positions H1 and H2 are positions in the Z direction when the inner surface IF3 of outer wall 120e is used as the starting point, and position H2 is a position in the +Z direction from position H1. Therefore, electrode 220b is disposed in the +Z direction from electrode 220a. Hereinafter, a position in the +Z direction from a specific position is also referred to as a position higher than the specific position, and a position in the -Z direction from the specific position is also referred to as a position lower than the specific position.

[0112] The electrode 220a may be arranged such that the -Z side of the two sides of the electrode 220a along the X direction is at position H1, or the +Z side of the electrode 220a is at position H1. Similarly, the electrode 220b may be arranged such that the -Z side of the two sides of the electrode 220b along the X direction is at position H2, or the +Z side of the electrode 220b is at position H2.

[0113] In this embodiment, the shield wirings 240d, 240e are provided on the FPC 200, and therefore it is possible to reduce interference between the multiple FPCs 200 that correspond one-to-one to the multiple ink tanks 100 of the tank unit 10. Interference between the FPCs 200 occurs when a signal from one of the two FPCs 200 is transmitted as noise to one or both of the electrodes 210 and 220 of the other FPC 200.

[0114] Furthermore, a large amplitude signal of about 42 V is supplied to the piezoelectric element that drives the ejection portion 30a of the print head 30. In this embodiment, since the shield wiring 240d, 240e is provided on the FPC 200, it is possible to reduce the large amplitude signal supplied to the piezoelectric element from being transmitted as noise to one or both of the electrodes 210 and 220.

[0115] In addition, in this embodiment, since the FPC 200 is fixed to the ink tank 100 with the double-sided tape 260 of a substantially uniform thickness, the distance between the electrode 210 and the outer surface OF1a of the first arrangement portion PP1 and the distance between the electrode 220 and the outer surface OF2a of the second arrangement portion PP2 are substantially constant. Therefore, in this embodiment, it is possible to suppress uneven distribution of the adhesive compared to when the FPC 200 is fixed to the ink tank 100 with a general curing adhesive. In other words, in this embodiment, it is possible to suppress the distance between the electrode 210 and the electrode 220 from varying depending on the position within the electrode 220 compared to when the FPC 200 is fixed to the ink tank 100 with a general curing adhesive.

[0116] In this embodiment, the inner surface IF1 opposite to the outer surface OF1 of the outer wall 120a and the inner surface IF2 opposite to the outer surface OF2 of the outer wall 120b are subjected to a water-repellent treatment. Specifically, the water-repellent treatment is applied to a portion of the inner surface IF1 of the outer wall 120a exposed to the space SP and a portion of the inner surface IF2 of the outer wall 120b exposed to the space SP. That is, the water-repellent treatment is not applied to the portion of the inner surface IF1 of the outer wall 120a that is bonded to the outer walls 120c, 120d, and 120e and the portion that is bonded to the partition walls 122a and 122b. The water-repellent treatment is, for example, a water-repellent treatment by a silicone-based coating. Note that the water-repellent treatment is not limited to the water-repellent treatment by a silicone-based coating. For example, the water-repellent treatment may be a water-repellent treatment by a fluorine-based coating.

[0117] In this embodiment, among the inner surfaces IF1 of the outer wall 120a, the reference numeral of the inner surface IF1 of the first arrangement portion PP1 has a lowercase alphabet "a" added to the end of the reference numeral. Similarly, among the inner surfaces IF2 of the outer wall 120b, the reference numeral of the inner surface IF2 of the second arrangement portion PP2 has a lowercase alphabet "a" added to the end of the reference numeral.

[0118] The range to which the water-repellent treatment is applied is not limited to the above example, as long as the water-repellent treatment is applied to the inner surface IF1a of the first arrangement portion PP1 of the outer wall 120a and the inner surface IF2a of the second arrangement portion PP2 of the outer wall 120b. For example, the water-repellent treatment may be applied to the inner surface IF1a of the first arrangement portion PP1 and the inner surface IF2a of the second arrangement portion PP2 by a fluorine-based coating or a silicone-based coating.

[0119] In this embodiment, the water-repellent treatment is applied to the inner surface IF1a of the first arrangement portion PP1 and the inner surface IF2a of the second arrangement portion PP2, so that the water-repellent properties of the inner surface IF1a of the first arrangement portion PP1 and the inner surface IF2a of the second arrangement portion PP2 can be improved. As a result, in this embodiment, it is possible to suppress adhesion of ink INK to the inner surfaces IF1a and IF2a compared to a case in which the inner surfaces IF1a and IF2a are not subjected to the water-repellent treatment.

[0120] When ink INK adheres to the inner surfaces IF1a and IF2a, there is a risk that the accuracy of detecting the amount of ink INK stored in the ink tank 100 will decrease compared to when ink INK is not adhered to the inner surfaces IF1a and IF2a. In this embodiment, since it is possible to prevent ink INK from adhering to the inner surfaces IF1a and IF2a, the control unit 4 can improve the accuracy of detecting the amount of ink INK stored in the ink tank 100.

[0121] In addition, in the present embodiment, as described above, the portions of the inner surface IF1 of the outer wall 120a that are bonded to the outer walls 120c, 120d, and 120e and the portions that are bonded to the partition walls 122a and 122b are not subjected to a water-repellent treatment. Therefore, in the present embodiment, it is possible to suppress a decrease in the adhesive strength between the outer walls 120c, 120d, and 120e and the outer wall 120a and between the partition walls 122a and 122b and the outer wall 120a.

[0122] Here, when ink INK is ejected from the ejection unit 30a of the print head 30, the amount of ink INK stored in the ink tank 100 decreases, and the liquid level L of the ink INK drops. In this embodiment, the control unit 4 can grasp the amount of ink INK stored in the ink tank 100, i.e., the remaining amount of ink INK, by detecting the liquid level L of the ink INK. The inkjet printer 1 may also have a notification unit that notifies the user of the inkjet printer 1 of the remaining amount of ink INK. For example, the notification unit may notify the user of the inkjet printer 1 of the remaining amount of ink INK by displaying the remaining amount of ink INK under the control of the control unit 4.

[0123] Next, a method for detecting the amount of ink INK stored in the ink tank 100 will be outlined with reference to FIG.

[0124] Fig. 9 is an explanatory diagram for explaining an outline of a method for detecting the amount of ink INK stored in the ink tank 100. Fig. 9 shows a cross section of the ink tank 100 and the FPC 200 taken along the line A1-A2 shown in Fig. 4. In Fig. 9, similarly to Fig. 8, elements located in the +Z direction from the partition wall 122b, the support portion 130, etc. are omitted in order to make the drawing easier to see.

[0125] Capacitor CCa is composed of electrode 210, electrode 220a, and dielectrics present between electrode 210 and electrode 220a. Major dielectrics present between electrode 210 and electrode 220a include, for example, double-sided tape 260, outer wall 120a, one or both of ink INK and air, and outer wall 120b. The capacitance of capacitor CCa is represented by, for example, a composite capacitance of multiple capacitors divided based on multiple dielectrics present between electrode 210 and electrode 220a.

[0126] 9, it is assumed that the capacitor CCa is divided into capacitors Ca1 and Ca5, which use the double-sided tape 260 as a dielectric, capacitors Ca2 and Ca3, which use the outer wall 120a as a dielectric, and capacitor Ca4, which uses the outer wall 120b as a dielectric. Note that the capacitor Ca3 is a capacitor that uses one or both of the ink INK and air as a dielectric, among the dielectrics present between the electrode 210 and the electrode 220a.

[0127] Furthermore, a capacitor CCb is formed by the electrodes 210 and 220b and a dielectric present between the electrodes 210 and 220b. The dielectric present between the electrodes 210 and 220b is the same as the dielectric present between the electrodes 210 and 220a. For example, the capacitor CCb is divided into capacitors Cb1 and Cb5 using the double-sided tape 260 as a dielectric, capacitors Cb2 and Cb3 using the outer wall 120a as a dielectric, and capacitor Cb4 using the outer wall 120b as a dielectric.

[0128] The capacitance CC of each of the capacitors CCa and CCb is expressed by equation (1) using capacitances C1, C2, C3, C4, and C5 of a plurality of capacitors obtained by dividing each of the capacitors CCa and CCb. CC=1 / (1 / C1+1 / C2+1 / C3+1 / C4+1 / C5) ···(1)

[0129] In this embodiment, since it is assumed that the electrodes 220a and 220b are the same size, C1 in formula (1) indicates the capacitance of the capacitors Ca1 and Cb1, and C2 indicates the capacitance of the capacitors Ca2 and Cb2. Furthermore, C4 in formula (1) indicates the capacitance of the capacitors Ca4 and Cb4, and C5 indicates the capacitance of the capacitors Ca5 and Cb5. Furthermore, when formula (1) indicates the capacitance C of the capacitor CCa, C3 indicates the capacitance of the capacitor Ca3, and when formula (1) indicates the capacitance C of the capacitor CCb, C3 indicates the capacitance of the capacitor Cb3.

[0130] In the following, the capacitances CC, C1, C2, C3, C4, and C5 may be collectively referred to as capacitance C. The capacitance C [F] is expressed by equation (2). C = ε0 * ε1 * S / d (2)

[0131] In addition, "*" in formula (2) indicates multiplication. In addition, S in formula (2) indicates the area of ​​electrode 220a or electrode 220b, and d indicates the distance between the electrodes of the capacitor. In the example shown in FIG. 9, the length in the Y direction of the dielectric material of the capacitor corresponds to the distance d. In addition, ε0 in formula (2) indicates the dielectric constant of a vacuum, and ε1 indicates the relative dielectric constant of the dielectric material of the capacitor.

[0132] As shown in formula (2), the capacitance C increases in proportion to the relative dielectric constant ε1 of the dielectric of the capacitor. Note that, among the capacitors Ca1 to Ca5 and Cb1 to Cb5, the relative dielectric constant ε1 of the capacitors other than the capacitors Ca3 and Cb3 does not change even if the amount of ink INK stored in the ink tank 100 changes. In contrast, the relative dielectric constant ε1 of the capacitors Ca3 and Cb3, which use either or both of the ink INK and air as a dielectric, varies depending on the amount of ink INK stored in the ink tank 100.

[0133] In the capacitor Ca3, the relative dielectric constant ε1 changes depending on the ratio of the ink INK and the air present between the electrode 210 and the electrode 220a. The relative dielectric constant ε1 of the ink INK is greater than the relative dielectric constant ε1 of the air. The relative dielectric constant ε1 of the ink INK differs depending on the material of the ink INK, but is approximately 80 if considered to be close to the relative dielectric constant of water. The relative dielectric constant ε1 of air is approximately 1.

[0134] In this way, the capacitance C3 of capacitors Ca3 and Cb3 changes depending on the amount of ink INK stored in the ink tank 100. The effect of the change in capacitance C3 of capacitor Ca3 on capacitor CCa is greater when the capacitance C of capacitors other than capacitor Ca3 is large, compared to when the capacitance C of capacitors other than capacitor Ca3 is small. Similarly, the effect of the change in capacitance C3 of capacitor Cb3 on capacitor CCb is greater when the capacitance C of capacitors other than capacitor Cb3 is large, compared to when the capacitance C of capacitors other than capacitor Cb3 is small.

[0135] The capacitance C increases in proportion to the inverse of the distance d between the electrodes of the capacitor. That is, when the length of the dielectric of the capacitor in the Y direction is small, the capacitance C is larger than when the length of the dielectric of the capacitor in the Y direction is large. For this reason, in this embodiment, as described in FIG. 8, the thickness T1 of the first arrangement portion PP1 of the outer wall 120a is thinner than the thickness T2 of the second arrangement portion PP2 of the outer wall 120b and the thickness T3 of the outer wall 120d. The thickness T1 of the first arrangement portion PP1 is not particularly limited as long as the thickness T1 is thinner than one of the thicknesses T2 and T3. For example, the thickness T1 of the first arrangement portion PP1 may be about 0.01 mm, and the thickness T2 of the second arrangement portion PP2 may be about 1 mm.

[0136] In this embodiment, since the thickness T1 of the first arrangement portion PP1 is thinner than the thicknesses T2 and T3, the capacitance C1 of the capacitors Ca1 and Cb1 can be made larger than when the thickness T1 of the first arrangement portion PP1 is the same as the thickness T2 or the thickness T3. This makes it possible to accurately detect the change in the capacitance C3 of each of the capacitors Ca3 and Cb3. As a result, in this embodiment, it is possible to improve the accuracy of detecting the amount of ink INK stored in the ink tank 100.

[0137] In this embodiment, it is assumed that the dielectric constant of the first arrangement portion PP1 of the outer wall 120a is higher than the dielectric constant of the second arrangement portion PP2 of the outer wall 120b and the dielectric constant of the outer wall 120d. In this case, the capacitance C1 of the capacitors Ca1 and Cb1 can be made larger than when the outer wall 120a is made of a material having the same dielectric constant as the outer wall 120b or the outer wall 120d.

[0138] In the example shown in FIG. 9, in order to reduce transmission of noise to the electrode 210, as well as the electrodes 220a and 220b, the terminal TMg of the shield wiring 240 is grounded via one of the external contacts CTg1 to CTg6.

[0139] Also, the terminal TMt1 of the electrode 210 is electrically connected to the power supply circuit 12 via the external contact CTt1. The power supply circuit 12 outputs, for example, an AC signal including a pulse with an amplitude of 3.3 [V] as an input signal Vin to the electrode 210. The input signal Vin is transmitted to the electrode 220a via the capacitor CCa as a detection signal Vout1, and transmitted to the electrode 220b via the capacitor CCb as a detection signal Vout2. The terminal TGr1 of the electrode 220a is electrically connected to an input terminal IN1 of the selection circuit 13, which will be described later in FIG. 11, via the external contact CTr1, and the terminal TGr2 of the electrode 220b is electrically connected to an input terminal IN2 of the selection circuit 13 via the external contact CTr2. As a result, the detection signals Vout1 and Vout2 are input to the selection circuit 13.

[0140] In addition, the amplitude of the detection signal Vout1 is larger when the capacitance CC of the capacitor CCa is large than when the capacitance CC of the capacitor CCa is small. The amplitude of the detection signal Vout1 is larger when the capacitance C3 of the capacitor Ca3 is large than when the capacitance C3 of the capacitor Ca3 is small. That is, when the space between the electrodes 210 and 220a is filled with ink INK, the amplitude of the detection signal Vout1 is larger than when the space between the electrodes 210 and 220a is filled with air. Similarly, when the space between the electrodes 210 and 220b is filled with ink INK, the amplitude of the detection signal Vout2 is larger than when the space between the electrodes 210 and 220b is filled with air.

[0141] 9, the liquid level L of the ink INK is located between the liquid level range LV1 and the liquid level range LV2, and therefore the amplitude of the detection signal Vout1 is greater than the amplitude of the detection signal Vout2. The liquid level range LV1 corresponds to the position of the electrode 220a in the Z direction, and is the range from the -Z side to the +Z side of the two sides of the electrode 220a along the X direction. The liquid level range LV2 corresponds to the position of the electrode 220b in the Z direction, and is the range from the -Z side to the +Z side of the two sides of the electrode 220b along the X direction.

[0142] Next, with reference to FIG. 10, the relationship between the liquid level L of the ink INK in the ink tank 100 and the detection signals Vout1, Vout2 will be described.

[0143] FIG. 10 is an explanatory diagram for explaining the relationship between the liquid level L of the ink INK in the ink tank 100 and the detection signals Vout1 and Vout2. Hereinafter, the detection signals Vout1 and Vout2 may be collectively referred to as the detection signal Vout. The horizontal axis of the diagram indicates the position of the liquid level L of the ink INK in the Z direction. Position H2 is a position in the +Z direction from position H1. Furthermore, the liquid level range LV2 is located in the +Z direction from the liquid level range LV1. In other words, the liquid level range LV2 is located above the liquid level range LV1. Furthermore, the vertical axis of the diagram indicates the magnitude of the detection signal Vout, which is the voltage of the electrode 220. The magnitude of the detection signal Vout may be, for example, the amplitude of the detection signal Vout or the effective value of the detection signal Vout. The voltage VH is greater than the voltage Vth, and the voltage Vth is greater than the voltage VL.

[0144] The voltage Vth is a threshold voltage when the magnitude of the detection signal Vout is expressed by two values ​​such as a high level and a low level. For example, the voltage Vth may be a central voltage between the voltages VL and VH, a voltage between the voltages VL and VH that is closer to the voltage VL than the voltage VH, or a voltage between the voltages VL and VH that is closer to the voltage VH than the voltage VL.

[0145] When the space between the electrodes 210 and 220a is filled with air and no ink INK is present between the electrodes 210 and 220a, the magnitudes of the detection signals Vout1 and Vout2 are voltage VL. The magnitude of the detection signal Vout1 increases when the proportion of ink INK present between the electrodes 210 and 220a increases. When the magnitude of the detection signal Vout1 is voltage Vth, it can be considered that the ink level L of the ink is present in a liquid level range LV1 including the position H1 where the electrode 220a is located. When the space between the electrodes 210 and 220a is filled with ink INK and no air is present between the electrodes 210 and 220a, the magnitude of the detection signal Vout1 is voltage VH.

[0146] The magnitude of the detection signal Vout2 increases when the proportion of ink INK present between the electrodes 210 and 220b increases. When the magnitude of the detection signal Vout2 is voltage Vth, it can be considered that the ink level L of the ink is present in a liquid level range LV2 that includes the position H2 where the electrode 220b is located. When the space between the electrodes 210 and 220b is filled with ink INK and no air is present between the electrodes 210 and 220b, the magnitude of the detection signal Vout2 is voltage VH.

[0147] Next, the control unit 4 will be described with reference to Fig. 11. Fig. 11 is a diagram showing an example of the configuration of a portion of the control unit 4. Fig. 11 is a diagram showing an excerpt of a portion of the control unit 4 that performs a process of heating the ink INK in one of the ink tanks 100 of the multiple ink tanks 100 in the tank unit 10 and a process of detecting the amount of ink INK stored therein. In Fig. 11, for ease of understanding, the tank unit 10 is shown as an equivalent circuit represented by capacitors CCa and CCb.

[0148] 11, the control unit 4 has a CPU 11, a power supply circuit 12, a selection circuit 13, and a detection circuit 20. The detection circuit 20 is a circuit that detects the amount of ink INK stored in the ink tank 100, and has a bias circuit 22, a buffer circuit 23, a BPF (Band Pass Filter) 24, an SH (Sample and Hold) circuit 25, an LPF (Low Pass Filter) 26, an amplifier circuit 27, and an ADC (Analog to Digital Converter) 28. The CPU 11 controls the power supply circuit 12, the selection circuit 13, and the detection circuit 20.

[0149] The selection circuit 13 has input terminals IN1 and IN2 and an output terminal OT. The input terminal IN1 of the selection circuit 13 is electrically connected to an external contact CTr1 that contacts the terminal TGr1, and the input terminal IN2 of the selection circuit 13 is electrically connected to an external contact CTr2 that contacts the terminal TGr2. That is, the input terminal IN1 of the selection circuit 13 is electrically connected to the electrode 220a via the external contact CTr1 and the terminal TGr1, and the input terminal IN2 of the selection circuit 13 is electrically connected to the electrode 220b via the external contact CTr2 and the terminal TGr2. The output terminal OT of the selection circuit 13 is electrically connected to the buffer circuit 23 via the bias circuit 22. Then, the selection circuit 13 electrically connects the input terminals IN1 and IN2 to the output terminal OT or grounds them, respectively, according to the control by the CPU 11.

[0150] During the first period, the CPU 11 grounds both input terminals IN1 and IN2 of the selection circuit 13 and causes the power supply circuit 12 to output an input signal Vin, which is an AC signal of a first frequency of 3 MHz or more. The input signal Vin is applied to the electrode 210 via the external contact CTt1 and the terminal TMt1. This causes the ink INK stored in the ink tank 100 to be heated. That is, during the first period, the CPU 11 applies an AC signal of the first frequency to the electrode 210 to heat the ink INK.

[0151] The first frequency may be a predetermined frequency between 3 MHz and 300 MHz. In particular, the first frequency is preferably a frequency included in an ISM band such as the 13 MHz band, the 27 MHz band, or the 40 MHz band. In this case, a high-frequency electric field is generated between the electrode 210 and the electrodes 220a and 220b by the input signal Vin applied to the electrode 210, and the ink INK is heated by high-frequency dielectric heating.

[0152] During the first period, the CPU 11 may ground the input terminal IN1 of the selection circuit 13, switch the input terminal IN2 of the selection circuit 13 between grounding and high impedance, and cause the power supply circuit 12 to output the input signal Vin, which is an AC signal of a first frequency of 3 MHz or more. That is, during the first period, the CPU 11 may control whether to apply an AC voltage based on an AC signal of the first frequency between the electrodes 210 and 220a to heat the ink INK, and to apply an AC voltage based on an AC signal of the first frequency between the electrodes 210 and 220b to heat the ink INK. This allows the CPU 11 to adjust the volume of the ink INK heated by high-frequency dielectric heating, making it easier to control the ink INK to have an appropriate temperature.

[0153] Alternatively, the first frequency may be a predetermined frequency of 300 MHz or more and 300 GHz or less. In particular, the first frequency is preferably a frequency included in an ISM band such as 2.4 GHz band or 5.8 GHz band. In this case, microwaves are generated from the electrode 210 by the input signal Vin applied to the electrode 210, and the ink INK is heated by microwave heating. That is, the CPU 11 may apply an AC signal to the electrode 210 in the first period to generate microwaves and heat the ink INK. The microwaves are electromagnetic waves with a frequency of 300 MHz or more and 300 GHz or less, and may be electromagnetic waves in the UHF band of 300 MHz to 3 GHz, electromagnetic waves in the SHF band of 3 GHz to 30 GHz, or electromagnetic waves in the EHF band of 30 GHz to 300 GHz. UHF is an abbreviation for Ultra High Frequency, SHF is an abbreviation for Super High Frequency, and EHF is an abbreviation for Extremely High Frequency.

[0154] The CPU 11 controls the application of the input signal Vin to the electrode 210 based on the temperature detected by a temperature sensor 50 built into the head unit 6. For example, the CPU 11 may control the time for applying the input signal Vin to the electrode 210 by turning on or off the output of the input signal Vin from the power supply circuit 12 based on the temperature detected by the temperature sensor 50. The temperature sensor 50 is a sensor that detects the temperature of the ejection section 30a of the print head 30, and is provided, for example, near the print head 30 or inside the print head 30. By controlling the application of the input signal Vin to the electrode 210 by the CPU 11, the ink INK stored in the ink tank 100 becomes a constant temperature and the viscosity of the ink INK becomes a predetermined value.

[0155] In the first period, since the detection circuit 20 does not need to operate, the CPU 11 may stop the operation of the detection circuit 20.

[0156] In the second period, the CPU 11 causes the power supply circuit 12 to output an input signal Vin, which is an AC signal of a second frequency. The input signal Vin is applied to the electrode 210 via the external contact CTt1 and the terminal TMt1. As a result, detection signals Vout1 and Vout2 corresponding to the remaining amount of ink INK stored in the ink tank 100 are output from the electrodes 220a and 220b, respectively. The second frequency is lower than the first frequency. In other words, the second frequency is a frequency lower than 3 MHz.

[0157] Then, the CPU 11 detects the amount of ink INK stored in the ink tank 100 based on the voltage of the detection signal Vout1. That is, the CPU 11 applies an AC signal of a second frequency to the electrode 210 during the second period, and detects the amount of ink INK stored in the ink tank 100 based on the voltage of the electrode 220a. The CPU 11 also detects the amount of ink INK stored in the ink tank 100 based on the voltage of the detection signal Vout2. That is, the CPU 11 applies an AC signal of a second frequency to the electrode 210 during the second period, and detects the amount of ink INK stored in the ink tank 100 based on the voltage of the electrode 220b.

[0158] In reality, the CPU 11 causes the detection circuit 20 to detect the amount of stored ink INK. Therefore, during the second period, the CPU 11 electrically connects one of the input terminals IN1 and IN2 of the selection circuit 13 to the output terminal OT, and grounds the other of the input terminals IN1 and IN2. For example, during the first half of the second period, the CPU 11 electrically connects the input terminal IN1 of the selection circuit 13 to the output terminal OT, and grounds the input terminal IN2. Also, during the second half of the second period, the CPU 11 electrically connects the input terminal IN2 of the selection circuit 13 to the output terminal OT, and grounds the input terminal IN1.

[0159] That is, the selection circuit 13 outputs the detection signal Vout selected under the control of the CPU 11 from the detection signal Vout1 received at the input terminal IN1 and the detection signal Vout2 received at the input terminal IN2 from the output terminal OT to the buffer circuit 23. In this way, the selection circuit 13 switches the detection signal Vout to be output to the buffer circuit 23 between the detection signal Vout1 and the detection signal Vout2.

[0160] In the detection circuit 20, the bias circuit 22 biases the output terminal OT of the selection circuit 13, i.e., the input of the buffer circuit 23, to a predetermined bias voltage between the power supply voltage and the ground voltage. The bias circuit 22 may bias the input of the buffer circuit 23 with a predetermined bias current.

[0161] The buffer circuit 23 outputs the detection signal Vout output from the selection circuit 13 to the BPF 24. As described above, the detection signal Vout output from the selection circuit 13 is biased to a predetermined bias voltage by the bias circuit 22. In the buffer circuit 23, the input impedance is higher than the output impedance. The buffer circuit 23 is used for impedance conversion.

[0162] The BPF 24 removes frequency components outside a predetermined frequency range from the detection signal Vout output from the buffer circuit 23, and outputs a signal with components within the predetermined frequency range to the SH circuit 25.

[0163] The SH circuit 25 receives the input signal Vin output from the power supply circuit 12 and the signal output from the BPF 24. The SH circuit 25 samples the signal output from the BPF 24 at a period based on the period of the input signal Vin, and holds the voltage value of the sampled signal until the operation of the ADC 28 is completed. The SH circuit 25 also outputs the sampled signal to the LPF 26.

[0164] The LPF 26 removes frequency components higher than a predetermined threshold from the signal output from the SH circuit 25, and outputs the signal with frequency components equal to or lower than the predetermined threshold to the amplifier circuit 27. Therefore, the signal that has passed through the LPF 26 is a signal from which noise and other components with frequencies higher than the predetermined threshold have been removed.

[0165] The amplifier circuit 27 amplifies the signal output from the LPF 26 at a predetermined amplification factor, and outputs the amplified signal to the ADC 28. The signal output from the amplifier circuit 27 to the ADC 28 is an analog signal.

[0166] The ADC 28 converts the analog signal output from the amplifier circuit 27 into a digital signal. The ADC 28 then outputs the digital signal converted from the analog signal to the CPU 11 as an output signal Do. The output signal Do is a digital signal that indicates the magnitude of the detection signal Vout selected by the selection circuit 13 from the detection signals Vout1, Vout2. In this manner, the detection circuit 20 detects the amount of ink INK stored in the ink tank 100 by detecting the magnitudes of the detection signals Vout1, Vout2. The CPU 11 can identify the amount of ink INK stored in the ink tank 100 based on the output signal Do output from the detection circuit 20.

[0167] Specifically, the CPU 11 compares the value of the output signal Do with a judgment threshold. The judgment threshold is, for example, a threshold corresponding to the voltage Vth shown in FIG. 10. Then, when the value of the output signal Do indicating the magnitude of the detection signal Vout1 is smaller than the judgment threshold, the CPU 11 can judge that the liquid level L of the ink INK is at a position lower than the position H1 where the electrode 220a is arranged. Also, when the value of the output signal Do indicating the magnitude of the detection signal Vout2 is larger than the judgment threshold, the CPU 11 can judge that the liquid level L of the ink INK is at a position higher than the position H2 where the electrode 220b is arranged. Also, when the value of the output signal Do indicating the magnitude of the detection signal Vout1 is larger than the judgment threshold and the value of the output signal Do indicating the magnitude of the detection signal Vout2 is smaller than the judgment threshold, the CPU 11 can judge that the liquid level L of the ink INK is at a position between the position H1 and the position H2.

[0168] The configuration of the detection circuit 20 is not limited to the example shown in Fig. 11. For example, the detection circuit 20 may have a comparator that compares whether the output voltage of the amplifier circuit 27 is equal to or higher than a predetermined value instead of the ADC 28. For example, when the number of electrodes 220 is three or more, the selection circuit 13 has three or more input terminals IN in one-to-one correspondence with the three or more electrodes 220. The selection circuit 13 electrically connects one of the three or more input terminals IN to the output terminal OT and grounds the other input terminals IN.

[0169] In this embodiment, the inkjet printer 1 is an example of a "liquid ejection device." The ink INK is an example of a "liquid." The ink tank 100 is an example of a "container." The electrode 210 is an example of a "first electrode." The electrode 220a is an example of a "second electrode." The electrode 220b is an example of a "third electrode." The control unit 4 is an example of a "control unit."

[0170] As described above, in the inkjet printer 1 of this embodiment, the control unit 4 applies an AC signal of 3 MHz or more to the electrode 210 provided in the ink tank 100 that stores the ink INK to heat the ink INK. For example, the control unit 4 can apply an AC voltage of 3 MHz or more and 300 MHz or less between the electrode 210 and the electrode 220a provided in positions that sandwich a part of the ink tank 100, thereby efficiently heating the ink INK by high-frequency dielectric heating. Alternatively, the control unit 4 can apply an AC signal of 300 MHz or more and 300 GHz or less to the electrode 210 provided in the ink tank 100 to generate microwaves, thereby efficiently heating the ink INK by microwave heating.

[0171] Furthermore, in the inkjet printer 1 of this embodiment, the control unit 4 applies an AC voltage of 3 MHz or more and 300 MHz or less between the electrodes 210 and 220a, and controls whether or not to apply an AC voltage of 3 MHz or more and 300 MHz or less between the electrodes 210 and 220b, which are positioned to sandwich a part of the ink tank 100, thereby adjusting the amount of ink INK heated by high-frequency dielectric heating, making it easy to control the ink INK to an appropriate temperature.

[0172] Furthermore, according to the inkjet printer 1 of this embodiment, the control unit 4 can perform feedback control based on the temperature detected by the temperature sensor 50 so that the ink INK ejected from the ejection portion 30a of the print head 30 is at an appropriate temperature.

[0173] Thus, according to the inkjet printer 1 of this embodiment, the control unit 4 heats the ink INK in the ink tank 100, thereby maintaining the viscosity of the ink INK ejected from the ejection section 30a of the print head 30 at a desired value and ejecting an appropriate amount of ink INK, thereby improving the ejection accuracy of the ink INK.

[0174] Furthermore, according to the inkjet printer 1 of this embodiment, the electrode 210 and the electrodes 220a, 220b, which are provided in a position sandwiching a portion of the ink tank 100, are used both to heat the ink INK stored in the ink tank 100 during the first period and to detect the amount of ink INK stored in the ink tank 100 during the second period, which is advantageous for miniaturization and cost reduction.

[0175] 2. Variations The present invention is not limited to the present embodiment, and various modifications are possible within the scope of the present invention.

[0176] For example, in the above embodiment, an inkjet printer 1 in which the tank unit 10 is mounted on the carriage 32 has been exemplified, but the tank unit 10 does not have to be mounted on the carriage 32. Furthermore, the inkjet printer 1 may have a configuration in which each ink tank 100 of the tank unit 10 is replaced with an ink cartridge.

[0177] For example, in the above embodiment, a serial printer having a head unit 6 in which a print head 30 is mounted on a carriage 32 is exemplified as the inkjet printer 1, but the inkjet printer 1 may be a line printer that does not have a carriage and in which a head unit having a print head is fixed.

[0178] In the above embodiment, an inkjet printer 1 in which the control unit 4 is not mounted on the carriage 32 has been exemplified, but the control unit 4 may be mounted on the carriage 32. That is, the head unit 6 may have the control unit 4. Also, some of the components of the control unit 4 may be mounted on the carriage 32. That is, the head unit 6 may have some of the components of the control unit 4. For example, the detection circuit 20 may be mounted on the carriage 32, and the head unit 6 may have the detection circuit 20.

[0179] Furthermore, in the above embodiment, an inkjet printer 1 in which one electrode 210 is provided in each ink tank 100 has been exemplified, but multiple electrodes 210 may be provided in each ink tank 100. In this case, the control unit 4 controls whether or not to apply an AC signal of 300 MHz or more and 300 GHz or less to each of the multiple electrodes 210 during the first period, thereby controlling the number of electrodes 210 that generate microwaves and thereby controlling the volume of ink INK to be heated.

[0180] In the above embodiment, the inkjet printer 1 is illustrated in which the electrodes 210, 220a, and 220b provided in each ink tank 100 are used for both the process of heating the ink INK and the process of detecting the amount of stored ink INK. However, the electrodes used for the process of heating the ink INK and the electrodes used for the process of detecting the amount of stored ink INK may be different. For example, a first electrode may be provided in a flow path that supplies the ink INK from the ink tank 100 to the ejection section 30a, and the control unit 4 may apply an AC signal to the first electrode to generate microwaves to heat the ink INK. Furthermore, a second electrode may be provided in the flow path. For example, a first electrode and a second electrode may be provided at positions that sandwich a part of the flow path, and the control unit 4 may apply an AC voltage between the first electrode and the second electrode to heat the ink INK. Furthermore, a third electrode may be provided in the flow path. For example, a first electrode and a third electrode may be provided at positions sandwiching a part of the flow path, and the control unit 4 may apply an AC voltage between the first electrode and the second electrode to heat the ink INK, and may also control whether or not to apply an AC voltage between the first electrode and the third electrode to heat the ink INK. In this way, an inkjet printer in which the control unit 4 heats the flow path of the ink INK can also achieve the same effects as the inkjet printer 1.

[0181] The present invention includes configurations that are substantially the same as the configurations described in this embodiment, for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effects. The present invention also includes configurations in which non-essential parts of the configurations described in this embodiment are replaced. The present invention also includes configurations that achieve the same effects as the configurations described in this embodiment, or configurations that can achieve the same purpose. The present invention also includes configurations in which publicly known technology is added to the configurations described in this embodiment.

[0182] The above-described embodiment is merely an example, and the present invention is not limited to the above. For example, the embodiments can be appropriately combined.

[0183] The following can be derived from the above-described embodiment and modified examples.

[0184] One aspect of the liquid ejection device is A discharge unit that discharges liquid; A container for storing the liquid; a flow path for supplying the liquid from the container to the discharge portion; A first electrode provided in the container or the flow path; A control unit that applies an AC signal of 3 MHz or more to the first electrode to heat the liquid; Equipped with.

[0185] In this liquid ejection device, the viscosity of the liquid ejected from the ejection part can be adjusted to a desired value by applying an AC signal of 3 MHz or more to a first electrode provided in a container that stores the liquid or a flow path that supplies the liquid from the container to the ejection part to heat the liquid. Therefore, with this liquid ejection device, an appropriate amount of liquid is ejected from the ejection part, and the ejection accuracy of the liquid can be improved.

[0186] One aspect of the liquid ejection device is A second electrode is provided in the container or the flow path, the first electrode and the second electrode are provided at positions sandwiching a part of the container or a part of the flow path, The control unit is The liquid may be heated by applying an AC voltage based on the AC signal between the first electrode and the second electrode.

[0187] According to this liquid ejection device, an AC voltage is applied between the first electrode and the second electrode, so that the liquid can be efficiently heated by high-frequency dielectric heating.

[0188] One aspect of the liquid ejection device is a third electrode provided in the container or the flow path; the first electrode and the third electrode are provided at positions sandwiching a part of the container or a part of the flow path, The control unit is The AC voltage may be applied between the first electrode and the second electrode to heat the liquid, and it may be controlled whether or not the AC voltage is applied between the first electrode and the third electrode to heat the liquid.

[0189] With this liquid ejection device, the amount of liquid heated by high-frequency dielectric heating can be adjusted by controlling whether or not to heat the liquid by applying an AC voltage between the first electrode and the third electrode, making it easy to control the liquid to an appropriate temperature.

[0190] In one aspect of the liquid ejection device, The control unit is The liquid may be heated by applying the AC signal to the first electrode to generate microwaves.

[0191] According to this liquid ejection device, microwaves are generated by applying an AC signal to the first electrode, so that the liquid can be efficiently heated by microwave heating.

[0192] One aspect of the liquid ejection device is A temperature sensor is provided to detect the temperature of the discharge portion, The control unit is The application of the AC signal to the first electrode may be controlled based on the temperature detected by the temperature sensor.

[0193] According to this liquid ejection device, feedback control can be performed based on the temperature of the ejection portion detected by the temperature sensor so that the liquid ejected from the ejection portion has an appropriate temperature.

[0194] One aspect of the liquid ejection device is A second electrode is provided in the container or the flow path, The first electrode and the second electrode are provided at positions sandwiching a part of the container, The control unit is during a first period, the AC signal of a first frequency is applied to the first electrode to heat the liquid; In a second period, an AC signal having a second frequency lower than the first frequency may be applied to the first electrode, and the amount of the liquid stored in the container may be detected based on a voltage of the second electrode.

[0195] According to this liquid ejection device, the first electrode and the second electrode, which are arranged at positions sandwiching a part of the container, are used both to heat the liquid stored in the container and to detect the amount of liquid stored in the container, which is advantageous for miniaturization and cost reduction.

[0196] One aspect of the head unit is A discharge unit that discharges liquid; A container for storing the liquid; a flow path for supplying the liquid from the container to the discharge portion; A first electrode provided in the container or the flow path; Equipped with An AC signal of 3 MHz or more is applied to the first electrode to heat the liquid.

[0197] In this head unit, an AC signal of 3 MHz or more is applied to a first electrode provided in a container that stores the liquid or in a flow path that supplies the liquid from the container to the ejection unit, thereby heating the liquid, and the viscosity of the liquid ejected from the ejection unit can be set to a desired value. Therefore, with this head unit, an appropriate amount of liquid is ejected from the ejection unit, and the ejection accuracy of the liquid can be improved.

[0198] One aspect of the head unit is A second electrode is provided in the container or the flow path, the first electrode and the second electrode are provided at positions sandwiching a part of the container or a part of the flow path, An AC voltage based on the AC signal may be applied between the first electrode and the second electrode to heat the liquid.

[0199] One aspect of the head unit is a third electrode provided in the container or the flow path; the first electrode and the third electrode are provided at positions sandwiching a part of the container or a part of the flow path, The AC voltage may be applied between the first electrode and the second electrode to heat the liquid, and whether or not the liquid is heated by applying the AC voltage between the first electrode and the third electrode may be controlled.

[0200] In one embodiment of the head unit, The liquid may be heated by generating microwaves by applying the AC signal to the first electrode.

[0201] One aspect of the head unit is A temperature sensor is provided to detect the temperature of the discharge portion, The application of the AC signal to the first electrode may be controlled based on the temperature detected by the temperature sensor.

[0202] One aspect of the head unit is A second electrode is provided in the container or the flow path, The first electrode and the second electrode are provided at positions sandwiching a part of the container, In a first period, the AC signal of a first frequency is applied to the first electrode to heat the liquid, During a second period, an AC signal having a second frequency lower than the first frequency may be applied to the first electrode, and the amount of the liquid stored in the container may be detected based on the voltage of the second electrode. [Explanation of symbols]

[0203] 1...inkjet printer, 4...control unit, 6...head unit, 10...tank unit, 11...CPU, 12...power supply circuit, 13...selection circuit, 20...detection circuit, 22...bias circuit, 23...buffer circuit, 24...BPF, 25...SH circuit, 26...LPF, 27...amplification circuit, 28...ADC, 30...print head, 30a...ejection section, 32...carriage, 40...timing belt, 42...carriage guide shaft, 43...carriage transport mechanism, 44...transport roller, 45...media transport mechanism, 46...platen, 50...temperature sensor, 100...ink tank, 120...outer wall, 122...partition wall, 130...support section, 132...rod section, 134...plate section, 136...auxiliary support section, 140...auxiliary section, 150...discharge section, 160...supply port, 180...adjustment port, 190...mounting portion, 200...FPC, 201...first cover film layer, 202...first conductive layer, 203...base material layer, 204...second conductive layer, 205...second cover film layer, 210...electrode, 212...wiring, 220, 220a, 220b...electrodes, 222a, 222b...wiring, 240, 240a, 240b, 240c, 2 40d, 240e...shield wiring, 260...double-sided tape, 262...first adhesive layer, 264...base material, 266...second adhesive layer, BP1, BP2...folded portion, IF1, IF1a, IF2, IF2a...inner surface, OF1, OF1a, OF2, OF2a...outer surface, PP1...first arrangement portion, PP2...second arrangement portion, PT10, PT12, PT20, PT22...positioning portion

Claims

1. A discharge unit that discharges liquid; A container for storing the liquid; a flow path for supplying the liquid from the container to the discharge portion; A first electrode provided in the container or the flow path; A control unit that applies an AC signal of 3 MHz or more to the first electrode to heat the liquid; Equipped with A liquid ejection device comprising:

2. A second electrode is provided in the container or the flow path, the first electrode and the second electrode are provided at positions sandwiching a part of the container or a part of the flow path, The control unit is applying an AC voltage based on the AC signal between the first electrode and the second electrode to heat the liquid; The liquid ejection device according to claim 1 .

3. A third electrode is provided in the container or the flow path, the first electrode and the third electrode are provided at positions sandwiching a part of the container or a part of the flow path, The control unit is applying the AC voltage between the first electrode and the second electrode to heat the liquid, and controlling whether or not to apply the AC voltage between the first electrode and the third electrode to heat the liquid. The liquid ejection device according to claim 2 .

4. The control unit is applying the AC signal to the first electrode to generate microwaves and heat the liquid; The liquid ejection device according to claim 1 .

5. A temperature sensor is provided to detect the temperature of the discharge portion, The control unit is controlling application of the AC signal to the first electrode based on the temperature detected by the temperature sensor; The liquid ejection device according to claim 1 .

6. A second electrode is provided in the container or the flow path, The first electrode and the second electrode are provided at positions sandwiching a part of the container, The control unit is during a first period, the AC signal of a first frequency is applied to the first electrode to heat the liquid; during a second period, an AC signal having a second frequency lower than the first frequency is applied to the first electrode, and an amount of the liquid stored in the container is detected based on a voltage of the second electrode; The liquid ejection device according to claim 1 .

7. A discharge unit that discharges liquid; A container for storing the liquid; a flow path for supplying the liquid from the container to the discharge portion; A first electrode provided in the container or the flow path; Equipped with An AC signal of 3 MHz or more is applied to the first electrode to heat the liquid. A head unit characterized by:

8. A second electrode is provided in the container or the flow path, the first electrode and the second electrode are provided at positions sandwiching a part of the container or a part of the flow path, An AC voltage based on the AC signal is applied between the first electrode and the second electrode to heat the liquid.

8. The head unit according to claim 7.

9. A third electrode is provided in the container or the flow path, the first electrode and the third electrode are provided at positions sandwiching a part of the container or a part of the flow path, The AC voltage is applied between the first electrode and the second electrode to heat the liquid, and the AC voltage is applied between the first electrode and the third electrode to control whether the liquid is heated or not.

9. The head unit according to claim 8.

10. When the AC signal is applied to the first electrode, microwaves are generated and the liquid is heated.

8. The head unit according to claim 7.

11. A temperature sensor is provided to detect the temperature of the discharge portion, The application of the AC signal to the first electrode is controlled based on the temperature detected by the temperature sensor.

8. The head unit according to claim 7.

12. A second electrode is provided in the container or the flow path, The first electrode and the second electrode are provided at positions sandwiching a part of the container, In a first period, the AC signal of a first frequency is applied to the first electrode to heat the liquid, In a second period, an AC signal having a second frequency lower than the first frequency is applied to the first electrode, and the amount of the liquid stored in the container is detected based on a voltage of the second electrode.

8. The head unit according to claim 7.

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