Tank unit, head system, ink supply system, printing system, and printing method

Abstract

To improve flexibility of an installation site of a tank unit which relays a head unit and a base unit.SOLUTION: A tank unit 30 includes: a bottom wall 30a; a bottom wall 30b which is located at a higher position than the bottom wall 30a and formed with openings OP1, OP2 penetrating through the bottom wall 30b in a vertical direction; a side wall 30c connected to the bottom wall 30a and the bottom wall 30b; a head tank 32 which is disposed on an upper surface of the bottom wall 30a and in which ink is stored; a liquid surface detection sensor 32a which detects a liquid surface of the ink in the head tank 32; a relay substrate 31 electrically connected to the liquid surface detection sensor 32a; a wiring cable W1 connected at one end to the relay substrate 31; a tube IT1 connected at one end to the head tank 32; a connector CN1 which is positioned at an inner side of the opening OP2 of the bottom wall 30b and connected with the other end of the wiring cable W1; and a coupler CP1 which is positioned at the inner side of the opening OP1 of the bottom wall 30b and connected with the other end of the tube IT1.SELECTED DRAWING: Figure 4b

Description

[Technical Field]

[0001] The present invention relates to a tank unit, a head system, an ink supply system, a printing system, and a printing method. [Background technology]

[0002] Conventionally, inkjet printers have been known that include a control unit, a print drive unit electrically connected to the control unit, and a print head electrically connected to the print drive unit. For example, in the inkjet printer disclosed in Patent Document 1, the control unit and the print drive unit are connected by a cable, and the print drive unit and the print head are connected by a separate cable. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-58282 Summary of the Invention [Problem to be solved by the invention]

[0004] In the inkjet printer disclosed in Patent Document 1, the direction in which the cable connecting the control unit and print drive unit extends crosses the direction in which the cable connecting the print drive unit and print head extends. As a result, when installing the print drive unit, it is necessary to secure not only space for the print drive unit, but also space in the direction in which each cable extends, which poses a problem of limiting the installation location of the print drive unit.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to improve the flexibility of the installation location of the tank unit that connects the head unit and the base unit, and to provide a head system, an ink supply system, a printing system, and a printing method that include such a tank unit. [Means for solving the problem]

[0006] According to a first aspect of the present invention, a first bottom wall extending in a first direction along a horizontal plane and a second direction along the horizontal plane and intersecting the first direction; a second bottom wall located above the first bottom wall, extending in the first direction and the second direction, the second bottom wall having an opening formed therethrough in a vertical direction; a first side wall extending in the vertical direction and the second direction, the upper end of which is connected to an end of the second bottom wall on one side in the first direction, and the lower end of which is connected to an end of the first bottom wall on the other side in the first direction; a tank disposed on an upper surface of the first bottom wall and configured to store ink; a liquid level detection sensor that detects the liquid level of the ink in the tank; a substrate electrically connected to the liquid level detection sensor; a first internal wiring having one end connected to the substrate; a first internal tube having one end connected to the tank and through which the ink supplied to the tank flows; a first electrical interface located inside the opening of the second bottom wall and connected to the other end of the first internal wiring; A tank unit is provided, the tank unit including a first fluid interface located inside the opening in the second bottom wall and connected to the other end of the first inner tube.

[0007] According to a second aspect of the present invention, a head unit having a head in which nozzles are formed; a tank unit according to the first aspect connected to the head unit and configured to supply ink to the head unit.

[0008] According to a third aspect of the present invention, An ink supply device; and a tank unit according to the first aspect, which is connected to the ink supply machine and configured to receive ink from the ink supply machine.

[0009] According to a fourth aspect of the present invention, a head unit having a head in which nozzles are formed; a tank unit according to the first aspect, connected to the head unit and configured to supply ink to the head unit; An ink supply connected to the tank unit and configured to supply the ink to the tank unit is provided.

[0010] According to a fifth aspect of the present invention, transporting the print medium by a conveyor; There is provided a printing method including ejecting ink from the head system according to the second aspect or the printing system according to the fourth aspect onto a print medium transported by a conveyor. [Effects of the Invention]

[0011] According to the first to fifth aspects of the present invention, it is possible to provide a tank unit with improved freedom in installation location, and a head system, ink supply system, printing system, and printing method that include such a tank unit. [Brief explanation of the drawings]

[0012] [Figure 1a] FIG. 1 is a diagram showing an inkjet printer in use. [Figure 1b] 10A and 10B are diagrams illustrating other usage states of the inkjet printer. [Figure 2] FIG. 1 is a diagram illustrating an outline of an ink supply system of an inkjet printer. [Figure 3] FIG. 2 is a diagram illustrating an outline of electrical connections between a base unit, a tank unit, a head unit, an operation panel, and an external device. [Figure 4a]FIG. [Figure 4b] FIG. [Figure 4c] FIG. 2 is a perspective view showing the internal structure of the tank unit. [Figure 4d] FIG. 2 is a front view showing the internal structure of the tank unit. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of a printing system according to the present invention will be described using an inkjet printer as an example.

[0014] First, an overview of the inkjet printer 10 will be described with reference to Figures 1a and 1b. In the following description, the direction from the far side of the page to the near side in Figures 1a and 1b will be referred to as the x-direction, the direction from left to right on the page as the y-direction, and the direction from bottom to top on the page as the z-direction. That is, the x-direction and y-direction are parallel to the horizontal plane and perpendicular to each other. The z-direction is parallel to the vertical plane and perpendicular to the x-direction and y-directions. In each figure, the tip of an arrow indicating the x-direction may be referred to as one side of the x-direction, and the base of an arrow indicating the x-direction may be referred to as the other side of the x-direction. The tip of an arrow indicating the y-direction may be referred to as one side of the y-direction, and the base of an arrow indicating the y-direction may be referred to as the other side of the y-direction. The tip of an arrow indicating the z-direction may be referred to as one side of the z-direction, and the base of an arrow indicating the z-direction may be referred to as the other side of the z-direction.

[0015] As shown in Figures 1a and 1b, the inkjet printer 10 mainly comprises a base unit 20, a tank unit 30, a head unit 40, and an operation panel 50. The base unit 20 and the tank unit 30 are connected by a tube T1 and a wiring cable C1, which serve as ink flow paths. The tank unit 30 and the head unit 40 are connected by tubes T2 and T3, which serve as ink flow paths, and a wiring cable C2. The operation panel 50 and the base unit 20 are connected by a wiring cable C3. The base unit 20, the tank unit 30, the head unit 40, and the operation panel 50 are fixed to a rack R, thereby determining their relative positions.

[0016] The base unit 20 functions as an ink supply device that supplies ink to the tank unit 30 via a tube T1. The tank unit 30 functions as a relay device that supplies ink supplied from the base unit 20 to the head unit 40 via tubes T2 and T3. In other words, the base unit 20 and the tank unit 30 function as an ink supply system that supplies ink to the head unit 40. The tank unit 30 and the head unit 40 also function as a head system to which ink is supplied from the base unit 20. The head unit 40 is provided with an inkjet head 42, and an ink ejection surface 42a of the inkjet head 42 has multiple nozzles formed thereon. The inkjet head 42 ejects ink supplied from the tank unit 30 from the multiple nozzles formed on the ink ejection surface 42a. The inkjet head 42 can be, for example, a so-called piezoelectric inkjet head that includes multiple nozzles, multiple individual flow paths that respectively communicate with the multiple nozzles, and multiple piezoelectric elements that apply ejection pressure to the ink in the multiple individual flow paths.

[0017] In this embodiment, the head unit 40 is configured to be attached to the rack R in a horizontal or vertical position. Here, the horizontal position refers to a position in which the ink ejection surface 42a of the inkjet head 42 is perpendicular to the y direction, as shown in FIG. 1a. In the horizontal position, ink is ejected horizontally (opposite the y direction) from the ink ejection surface 42a. On the other hand, the vertical position refers to a position in which the ink ejection surface 42a of the inkjet head 42 is perpendicular to the z direction, as shown in FIG. 1b. In the vertical position, ink is ejected vertically downward (opposite the z direction) from the ink ejection surface 42a. Here, as shown in FIGS. 1a and 1b, it is assumed that the print medium M is being transported in the x direction by a conveyor CV. In this case, by attaching the head unit 40 to the rack R in a horizontal position, as shown in FIG. 1a, printing can be performed on one side of the print medium M (the side perpendicular to the horizontal plane). On the other hand, as shown in FIG. 1b, by attaching the head unit 40 to the rack R in a vertical position, printing can be performed on the upper surface of the print medium M.

[0018] Next, the ink supply system of the inkjet printer 10 will be described. As shown in FIG. 2, the base unit 20 is provided with a main tank 22 and a pump 23. The main tank 22 is installed inside the base unit 20. The main tank 22 is provided with, for example, a float-type liquid level detection sensor 22a for detecting the ink level in the main tank 22. The main tank 22 also has an air vent formed therein, and the interior of the main tank 22 communicates with the atmosphere via the air vent. In this embodiment, the main tank 22 is installed inside the base unit 20, but the main tank 22 may be configured to be removable from the base unit 20 and replaceable. Alternatively, a replaceable ink tank may be provided separately that communicates with the main tank 22 and supplies ink to the main tank 22.

[0019] The tank unit 30 is provided with a head tank 32, a circulation pump 33, a purge pump 35, a solenoid valve 36, and an atmosphere communication flow path 37. The head tank 32 is installed inside the tank unit 30. The head tank 32 is provided with, for example, a float-type liquid level detection sensor 32a for detecting the ink level in the head tank 32. The atmosphere communication flow path 37 is provided with the purge pump 35 and the solenoid valve 36. The solenoid valve 36 normally connects the head tank 32 to the atmosphere, but during a purge process (described later), it blocks communication between the head tank 32 and the atmosphere and connects the head tank 32 to the purge pump 35. Therefore, the head tank 32 is in communication with the atmosphere except when the purge process is being performed.

[0020] The head unit 40 is provided with an inkjet head 42 and a damper 43. The damper 43 is provided to mitigate pressure fluctuations in the ink inside the inkjet head 42 that occur when, for example, the print medium being transported by the conveyor moves obliquely and collides with the inkjet head 42.

[0021] The main tank 22 and the head tank 32 are in communication with each other via a tube T0, a tube T1, and a tube IT1. One end of the tube T0 is connected to the main tank 22, and the other end of the tube T0 is connected to the pump 23. One end of the tube T1 is connected to the pump 23, and the other end of the tube T1 is connected to a coupler CP1 of the tank unit 30. One end of the tube IT1 is connected to the coupler CP1 of the tank unit 30, and the other end of the tube IT1 is connected to the head tank 32.

[0022] The head tank 32 and the damper 43 of the head unit 40 are in communication with each other via a tube IT2 and a tube T2. One end of the tube IT2 is connected to the head tank 32, and the other end of the tube IT2 is connected to the coupler CP2 of the tank unit 30. One end of the tube T2 is connected to the coupler CP2 of the tank unit 30, and the other end of the tube T2 is connected to the damper 43.

[0023] The damper 43 of the head unit 40 and the inkjet head 42 are in communication with each other via a tube T4. That is, one end of the tube T4 is connected to the damper 43, and the other end of the tube T4 is connected to the inkjet head 42. The inkjet head 42 and the head tank 32 are in communication with each other via a tube T3, a tube IT4, and a tube IT3. One end of the tube T3 is connected to the inkjet head 42, and the other end of the tube T3 is connected to a coupler CP3 of the tank unit 30. One end of the tube IT4 is connected to the coupler CP3 of the tank unit 30, and the other end of the tube IT4 is connected to a circulation pump 33 of the tank unit 30. One end of the tube IT3 is connected to the circulation pump 33 of the tank unit 30, and the other end of the tube IT3 is connected to the head tank 32.

[0024] When the inkjet printer 10 is initially installed, there is no ink in the head tank 32 or the inkjet head 42. Therefore, first, the controller 21 (see FIG. 3 ), which will be described later, drives the pump 23 to supply ink from the main tank 22 to the head tank 32 via the tubes T0, T1, and IT1. When the liquid level detection sensor 32a of the head tank 32 detects that the ink level in the head tank 32 has reached its upper limit, the controller 21 stops the pump 23. This stops the supply of ink to the head tank 32. Next, with the ink ejection surface 42a of the inkjet head 42 covered with a cap (not shown), the controller 21 drives the circulation pump 33 via the relay board 31 (see FIG. 3 ), which will be described later, of the tank unit 30. This causes ink to flow in the order of tube IT2, tube T2, tube T4, inkjet head 42, tube T3, tube IT4, and tube IT3, thereby filling the inkjet head 42 and the flow path connecting the inkjet head 42 and the head tank 32 with ink. When the ink is filled in the inkjet head 42 and the flow path connecting the inkjet head 42 and the head tank 32, the controller 21 stops the circulation pump 33 via the relay board 31. This stops the supply of ink to the inkjet head 42.

[0025] When ink is ejected from the inkjet head 42 while the inkjet head 42 and the flow path connecting the inkjet head 42 and the head tank 32 are filled with ink, the same amount of ink as the amount ejected from the inkjet head 42 is supplied from the head tank 32 to the inkjet head 42 via the tubes IT2, T2, and T4. As ink is continuously ejected from the inkjet head 42, the ink in the head tank 32 decreases. When the liquid level detection sensor 32a of the head tank 32 detects that the ink level in the head tank 32 has reached its lower limit, the controller 21 drives the pump 23. As a result, ink is supplied from the main tank 22 to the head tank 32 via the tubes T0, T1, and IT1. As ink is supplied to the head tank 32, the ink in the main tank 22 decreases. When the liquid level detection sensor 22a of the main tank 22 detects that the ink level in the main tank 22 has reached its lower limit, the controller 21 displays a message on, for example, the operation panel 50, urging the user to refill the main tank 22 with ink. Then, when the user sees the message urging the user to refill the main tank 22 with ink, the user can refill the main tank 22 with ink, thereby making it possible to supply ink from the main tank 22 to the head tank 32 again.

[0026] In this embodiment, in order to expel thickened ink in the inkjet head 42 or air bubbles mixed in the ink in the inkjet head 42 and the tubes IT2, T2, and T4 from the multiple nozzles of the ink ejection surface 42a, the controller 21 may execute a purge process in which ink is forcibly supplied from the head tank 32 to the inkjet head 42. In the purge process, the controller 21 controls the solenoid valve 36 to block communication between the head tank 32 and the atmosphere and to connect the head tank 32 to the purge pump 35. In this state, the controller 21 drives the purge pump 35 via the relay board 31 to create a positive pressure inside the head tank 32. As a result, ink is forcibly supplied from the head tank 32 to the inkjet head 42 via the tubes IT2, T2, and T4, and thickened ink and air bubbles in the inkjet head 42 are expelled from the multiple nozzles.

[0027] Next, the electrical connections between the base unit 20, the tank unit 30, the head unit 40, and the operation panel 50 will be described. As shown in FIG. 3 , the base unit 20 is provided with a controller 21, which is electrically connected to the liquid level detection sensor 22a and the pump 23. The controller 21 is also electrically connected to the operation panel 50, which serves as an input / output interface for the user. The tank unit 30 is provided with a relay board 31, which is electrically connected to the liquid level detection sensor 32a, the circulation pump 33, the purge pump 35, and the solenoid valve 36. The relay board 31 is also electrically connected to the controller 21 of the base unit 20 via wiring cables W1 and C1. One end of the wiring cable W1 is connected to the relay board 31, and the other end of the wiring cable W1 is connected to the connector CN1 of the tank unit 30. One end of the wiring cable C1 is connected to the connector CN1 of the tank unit 30, and the other end of the wiring cable C1 is connected to the controller 21. The head unit 40 is provided with a drive substrate 41, which is electrically connected to the inkjet head 42. The relay substrate 31 of the tank unit 30 and the drive substrate 41 are also electrically connected via wiring cables W2 and C2. One end of the wiring cable W2 is connected to the relay substrate 31, and the other end of the wiring cable W2 is connected to the connector CN2 of the tank unit 30. One end of the wiring cable C2 is connected to the connector CN2 of the tank unit 30, and the other end of the wiring cable C2 is connected to the drive substrate 41.

[0028] The controller 21 includes a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), and an application-specific integrated circuit (ASIC) including various control circuits. The controller 21 executes various processes using the CPU and ASIC in accordance with programs stored in the ROM. For example, the controller 21 generates a control signal based on a print job received from an external device 60 such as a PC and transmits the control signal to the drive board 41 via the relay board 31. The drive board 41 then generates a drive signal based on the control signal and drives the inkjet head 42 based on the drive signal, thereby executing a print process of printing an image or the like on the print medium M. The controller 21 also controls the pumps 23 and 33, the purge pump 35, the solenoid valve 36, the operation panel 50, and the like based on signals output from the liquid level detection sensors 22a and 32a, thereby executing ink supply processes and maintenance processes for the inkjet head 42. While the example in which the controller 21 executes a print process using the CPU and ASIC has been described, the present invention is not limited to this, and the controller 21 may be implemented using any hardware configuration. For example, the processing may be performed by only a CPU or only an ASIC, or the functions may be shared among two or more CPUs or two or more ASICs.

[0029] Next, details of the tank unit 30 will be described with reference to Figures 4a to 4d. As shown in Figures 4a and 4b, the tank unit 30 has a bottom wall 30a, a bottom wall 30b, a side wall 30c, a side wall 30d, a side wall 30e, an inclined wall 30f, a side wall 30g, a side wall 30h, and an upper wall 30i. Note that in Figure 4c, the upper wall 30i, the inclined wall 30f, the side wall 30e, and the side wall 30g are not shown in order to show the internal configuration of the tank unit 30. Also, in Figure 4d, the side wall 30e and the inclined wall 30f are not shown in order to show the internal configuration of the tank unit 30.

[0030] The bottom walls 30a, 30b and the top wall 30i have a rectangular shape extending in the x and y directions. The bottom wall 30b is located on one side of the bottom wall 30a in the z direction (upper side in FIG. 4a), and the top wall 30i is located on one side of the bottom wall 30b in the z direction.

[0031] The side wall 30c has a rectangular outer shape extending in the y and z directions. One end of the side wall 30c in the z direction is connected to one end of the bottom wall 30b in the x direction (the left side in FIG. 4a). The other end of the side wall 30c in the z direction (the bottom side in FIG. 4a) is connected to the other end of the bottom wall 30a in the x direction (the right side in FIG. 4a).

[0032] Each of the side walls 30d and 30g has a pentagonal outer shape parallel to the yz plane. The other end of the side wall 30d in the z direction (the lower side in FIG. 4a) is connected to the other end of the bottom wall 30b in the x direction. One end of the side wall 30d in the z direction is connected to the other end of the top wall 30i in the x direction. The other end of the side wall 30g in the z direction (the lower side in FIG. 4a) is connected to one end of the bottom wall 30a in the x direction. One end of the side wall 30g in the z direction is connected to one end of the top wall 30i in the x direction.

[0033] The side walls 30e and 30h each have a hexagonal shape parallel to a plane extending in the x and z directions. The side wall 30e is connected to the ends of the bottom walls 30a, 30b and side wall 30c on one side in the y direction (the front side in FIG. 4a) and to the portions of the ends of the side walls 30d and 30g on one side in the y direction that are parallel to the z direction. The side wall 30h is connected to the ends of the bottom walls 30a and 30b on the other side in the y direction (the back side in FIG. 4a) and to the ends of the side walls 30c, 30d, and 30g on the other side in the y direction.

[0034] The inclined wall 30f has a rectangular outer shape and is inclined with respect to a plane extending in the x and z directions. The inclined wall 30f is connected to one end of the side wall 30e in the z direction, one end of the top wall 30i in the y direction, an inclined portion of one end of the side wall 30d in the y direction that is inclined with respect to the z direction, and an inclined portion of one end of the side wall 30g in the y direction that is inclined with respect to the z direction.

[0035] As shown in FIG. 4c, a head tank 32, an interposer board 31, and a circulation pump 33 are arranged on one surface of the bottom wall 30a in the z direction. Tubes IT1, IT2 (see FIG. 2), and IT3 (see FIG. 2) are connected to the head tank 32. One end of an atmosphere-communicating flow path 37 (see FIG. 2) extending in the z direction is connected to one end of the head tank 32 in the z direction, and the other end of the atmosphere-communicating flow path 37 is connected to an opening formed in the bottom wall 30b, separate from the openings OP1 and OP2. The interposer board 31 has a rectangular shape extending in the x and z directions, and is located between the head tank 32 and the side wall 30e in the y direction. The circulation pump 33 is also located between the head tank 32 and the side wall 30e in the y direction.

[0036] As shown in FIG. 4b, two openings OP1 and OP2 are formed in the bottom wall 30b, penetrating in the z direction. A coupler CP1 is located inside the opening OP1. One end of the coupler CP1 protrudes from the opening OP1 in the direction opposite to the z direction. A tube T1 is connected to one end of the coupler CP1. As shown in FIG. 4c, a tube IT1 is connected to the other end of the coupler CP1. A connector CN1 is located inside the opening OP2. As shown in FIG. 4b, one end of the connector CN1 protrudes from the opening OP2 in the direction opposite to the z direction. A distribution cable C1 is connected to one end of the connector CN1. A distribution cable W1 (see FIG. 3) is connected to the other end of the connector CN1. As shown in FIGS. 4b and 4d, the coupler CP1 and the connector CN1 are aligned in the y direction. As shown in Figure 4b, the z-direction length h1 of the side wall 30c, in other words, the z-direction distance between the bottom wall 30a and the bottom wall 30b, is larger than the minimum bending radius of the tube T1 connected to one end of the coupler CP1, and is also larger than the minimum bending radius of the distribution cable C1 connected to one end of the connector CN1.

[0037] As shown in FIGS. 4a to 4d, the side wall 30d has openings at the ends of the cylindrical portions P1 to P4 extending in the x-direction from the side wall 30d. In other words, the side wall 30d has four openings and four cylindrical portions P1 to P4 extending in the x-direction from each of the four openings. A female thread is formed on the inside of each of the four cylindrical portions P1 to P4, and a male screw is inserted into each of the four cylindrical portions P1 to P4 to secure the tank unit 30 to the rack R. As shown in FIG. 4d, the length in the x-direction of each of the four cylindrical portions P1 to P4 is shorter than the length d1 in the x-direction of the bottom wall 30b (see FIG. 4d). In other words, the length d1 in the x-direction of the bottom wall 30b is longer than the length in the x-direction of each of the four cylindrical portions P1 to P4. Furthermore, the length h2 of the side wall 30d in the z direction (see FIG. 4b), in other words, the distance in the z direction from the bottom wall 30b to the top wall 30i, is greater than the minimum bending radius of the tube IT1 connected to the other end of the coupler CP1.

[0038] As shown in FIGS. 4a and 4b, a purge switch PS is provided on one side of the bottom wall 30b in the z direction on the inclined wall 30f, i.e., in the region overlapping with the bottom wall 30b in the z direction. When a user presses the purge switch SP, the above-described purge process is executed. As shown in FIGS. 4a and 4d, the length of the purge switch PS in the x direction is shorter than the length d1 of the bottom wall 30b in the x direction. In other words, the length d1 of the bottom wall 30b in the x direction is longer than the length of the purge switch PS in the x direction. Furthermore, as shown in FIG. 4d, the length d1 of the bottom wall 30b in the x direction is longer than the sum of the length of the cylindrical portion P1 in the x direction and the length of the purge switch PS in the x direction, and is longer than the sum of the length of the cylindrical portion P2 in the x direction and the length of the purge switch PS in the x direction.

[0039] As shown in Figures 4b and 4c, an opening OP3 is formed in the side wall 30h. Couplers CP2 and CP3 (see Figure 2) and a connector CN2 (see Figure 3) are provided inside the opening OP3. A tube IT2 (see Figure 2) is connected to one end of the coupler CP2, and a tube T2 (see Figure 2) is connected to the other end of the coupler CP2. A tube IT4 (see Figure 2) is connected to one end of the coupler CP3, and a tube T3 (see Figure 2) is connected to the other end of the coupler CP3. A wiring cable W2 (see Figure 3) is connected to one end of the connector CN2, and a wiring cable C2 is connected to the other end of the connector CN2.

[0040] As shown in Fig. 4c, a reinforcing frame FR extending in the x and y directions is provided inside the tank unit 30. As shown in Fig. 4d, a cylindrical portion P5 extending in the z direction is formed in the bottom wall 30b, and the reinforcing frame FR is fixed to one side in the z direction of the head tank 32 by screws inserted into the cylindrical portion P5. As shown in Figs. 4c and 4d, a purge pump 35, a solenoid valve 36, etc. are disposed on one surface of the reinforcing frame FR in the z direction. The purge pump 35 is located in the x direction between one end of the bottom wall 30b in the x direction and an atmosphere-communicating flow path 37 extending in the z direction. Also, as shown in Figure 4d, the x-direction length d1 of the bottom wall 30b is longer than the sum of the x-direction length of the cylindrical portion P1, the x-direction length of the purge switch PS, and the x-direction length of the cylindrical portion P5, and is longer than the sum of the x-direction length of the cylindrical portion P2, the x-direction length of the purge switch PS, and the x-direction length of the cylindrical portion P5.

[0041] In the tank unit 30 of this embodiment described above, the x direction, y direction, and z direction are examples of the "first direction," "second direction," and "vertical direction," respectively. The bottom walls 30a and 30b are examples of the "first bottom wall" and the "second bottom wall," respectively, and the side walls 30c and 30d are examples of the "first side wall" and the "second side wall," respectively. The side wall 30e and the inclined wall 30f are examples of the "third side wall," and the side wall 30h is an example of the "fourth side wall." The head tank 32 is an example of a "tank," and the relay board 31 is an example of a "board." The tubes IT1, T1, and IT2 are examples of the "first inner tube," the "first outer tube," and the "second inner tube," respectively, and the couplers CP1 and CP2 are examples of the "first fluid interface" and the "second fluid interface," respectively. The wiring cables W1, C1, and W2 are examples of the “first internal wiring,” “first external wiring,” and “second internal wiring,” respectively, and the connectors CN1 and CN2 are examples of the “first electrical interface” and the “second electrical interface,” respectively. The cylindrical portions P1 to P4 are examples of the “first cylindrical portion,” and the cylindrical portion P5 is an example of the “second cylindrical portion.”

[0042] In the tank unit 30 of the present embodiment described above, one end of the coupler C1 and one end of the connector CN1 protrude from the openings OP1 and OP2 in the bottom wall 30b toward the other side in the z direction, respectively. The tube T1 and the wiring cable C1 are connected to one end of the coupler C1 and one end of the connector CN1, respectively. The length h1 of the side wall 30c in the z direction—in other words, the distance in the z direction between the bottom wall 30a and the bottom wall 30b—is greater than the minimum bending radius of the tube T1 connected to one end of the coupler CP1 and the wiring cable C1 connected to one end of the connector CN1. Therefore, even when the tank unit 30 is placed with the bottom wall 30a attached to a horizontal surface, the tube T1 and the wiring cable C1 extending from the coupler CP1 and the connector CN1 toward the other side in the z direction can be bent and routed along the horizontal surface without breakage. This improves the flexibility of the installation location of the tank unit 30.

[0043] Furthermore, depending on the installation location of the tank unit 30, for example, an obstacle such as a wall may be present on the other side of the tank unit 30 in the x direction. Alternatively, a jig or the like may be placed against the side wall 30d of the tank unit 30, and the tank unit 30 may be fixed to the jig by inserting a screw into one of the cylindrical portions P1 to P4. In such a case, the user cannot access the coupler CP1 and the connector CN1 from the other side in the x direction. In this regard, in the present embodiment, one end of the coupler CP1 and one end of the connector CN1 protrude from the openings OP1 and OP2 in the bottom wall 30b, respectively, toward the other side in the z direction. Therefore, even if the user cannot access the coupler CP1 and the connector CN1 from the other side in the x direction, as described above, the user can access the coupler CP1 and the connector CN1 from one side in the y direction or the other side in the y direction and connect the tube T1 and the wiring cable C1. Even if there is no space to route the tube T1 or the wiring cable C1 on the other side in the x direction of the side wall 30d of the tank unit 30 due to such restrictions on the installation location, the tube T1 and the wiring cable C1 can be routed along the yz plane. In other words, the degree of freedom in the installation location of the tank unit 30 can be improved.

[0044] The other end of the coupler C1 is located on one side of the bottom wall 30b in the z direction, and the length h2 of the side wall 30d in the z direction, in other words, the distance in the z direction from the bottom wall 30b to the top wall 30i, is greater than the minimum bending radius of the tube IT1 connected to the other end of the coupler CP1. Therefore, the tube IT1 can be bent and routed inside the tank unit 30 without being damaged.

[0045] In the tank unit 30 of this embodiment, the z-direction length h1 of the side wall 30c is kept to the necessary minimum within a range greater than the minimum bending radius of the tube T1 and the minimum bending radius of the distribution cable C1, while the z-direction length h2 of the side wall 30d is kept to the necessary minimum within a range greater than the minimum bending radius of the tube IT1, thereby enabling the z-direction size of the tank unit 30 to be kept to the necessary minimum.

[0046] Furthermore, in the tank unit 30 of this embodiment, the x-direction length d1 of the bottom wall 30b is kept to a necessary minimum within a range longer than the sum of the x-direction length of the cylindrical portion P1, the x-direction length of the purge switch PS, and the x-direction length of the cylindrical portion P5, thereby enabling the x-direction size of the tank unit 30 to be kept to a necessary minimum.

[0047] In the tank unit 30 of this embodiment, the coupler CP1 and the connector CN1 are aligned in the y direction on the bottom wall 30b. Therefore, the size of the bottom wall 30b in the x direction can be minimized, and as a result, the size of the tank unit 30 in the x direction can be minimized.

[0048] Inside the tank unit 30 of this embodiment, a reinforcing frame FR is provided on one side in the z direction of the head tank 32. A purge pump 35 is disposed on one surface of the reinforcing frame FR in the z direction, and the purge pump 35 is located in the x direction between one end of the bottom wall 30b in the x direction and the atmosphere-communicating flow path 37 extending on one side in the z direction. This makes it possible to effectively utilize the space inside the tank unit 30 on one side in the z direction of the head tank 32, and to prevent the tank unit 30 from becoming larger.

[0049] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design modifications are possible within the scope of the claims.

[0050] In the above embodiment, openings OP1 and OP2 are formed in the bottom wall 30b, and one end of the coupler CP1 protrudes from opening OP1, and one end of the connector CN1 protrudes from opening OP2. However, this is not limited to this. For example, one end of the coupler CP1 and one end of the connector CN1 may protrude from one opening formed in the bottom wall 30b. Furthermore, the other end of the atmosphere communication channel 37 may be connected to the one opening.

[0051] In the above embodiment, the coupler CP1 and the connector CN1 are aligned in the y direction on the bottom wall 30b, but this is not limited to this. For example, if there is a wall or the like on the other side of the tank unit 30 in the x direction and a user accesses the coupler CP1 and the connector CN1 from one side in the y direction or the other side in the y direction to connect the tube T1 and the wiring cable C1, the coupler CP1 and the connector CN1 are offset in the x direction, allowing the user to more easily access the coupler CP1 and the connector CN1.

[0052] In the above embodiment, the float-type liquid level detection sensors 22a and 32a are used as the liquid level detection sensors that detect the amount of ink in the main tank 22 and the head tank 32, but this is not limiting. For example, an optical sensor equipped with a light-emitting element and a light-receiving element may also be used. [Explanation of symbols]

[0053] 10. Inkjet printer 20 base units 21 Controller 22 Main Tank 22a Liquid level detection sensor 23 Pump 30 Tank Unit 31 Relay board 32 Head Tank 32a Liquid level detection sensor 33 Circulation Pump 35 Purge pump 36 Solenoid valve 37 Atmospheric communication channel 40 Head Unit 41 Drive board 42 Inkjet head 50 Operation Panel CP1, CP2, CP3 couplers CN1, CN2 connectors T1~T4, IT1~IT4 tubes C1~C3, W1, W2 wiring cables

Claims

1. a first bottom wall extending in a first direction along a horizontal plane and in a second direction along the horizontal plane and intersecting the first direction; a second bottom wall located above the first bottom wall, extending in the first direction and the second direction, the second bottom wall having an opening formed therethrough in a vertical direction; a first side wall extending in a vertical direction and the second direction, the upper end of which is connected to an end of the second bottom wall on one side in the first direction, and the lower end of which is connected to an end of the first bottom wall on the other side in the first direction; a tank disposed on an upper surface of the first bottom wall and configured to store ink; a liquid level detection sensor that detects the liquid level of the ink in the tank; a substrate electrically connected to the liquid level detection sensor; a first internal wiring having one end connected to the substrate; a first internal tube having one end connected to the tank and through which the ink supplied to the tank flows; a first electrical interface located inside the opening of the second bottom wall and connected to the other end of the first internal wiring; a first fluid interface located inside the opening of the second bottom wall and connected to the other end of the first inner tube;

2. 2. The tank unit according to claim 1, wherein the vertical length of the first side wall is greater than the minimum bending radius of a first external wiring connected to the first electrical interface and greater than the minimum bending radius of a first external tube connected to the first fluid interface.

3. a second side wall extending in the vertical direction and the second direction, the lower end of which is connected to the other end of the second bottom wall in the first direction; The tank unit according to claim 1 or 2, wherein a vertical length of the second side wall is greater than a minimum bending radius of the first inner tube connected to the first fluid interface.

4. a first cylindrical portion extending from the second side wall to one side in the first direction is formed in the second side wall; The tank unit according to claim 3 , wherein the length of the second bottom wall in the first direction is longer than the length of the first cylindrical portion in the first direction.

5. a third side wall connected to one end of the first bottom wall in the second direction, one end of the first side wall in the second direction, one end of the second bottom wall in the second direction, and one end of the second side wall in the second direction; a fourth side wall extending in the vertical direction and the first direction and connected to an end of the first bottom wall on the other side in the second direction, an end of the first side wall on the other side in the second direction, an end of the second bottom wall on the other side in the second direction, and an end of the second side wall on the other side in the second direction, a switch is located on the third side wall vertically above the second bottom wall; The tank unit according to claim 4 , wherein the length of the second bottom wall in the first direction is longer than the length of the switch in the first direction.

6. The tank unit according to claim 5 , wherein the length of the second bottom wall in the first direction is longer than the sum of the length of the switch in the first direction and the length of the first cylindrical portion in the first direction.

7. The second bottom wall is formed with a second cylindrical portion extending upward from the second bottom wall, The tank unit of claim 6, wherein the length of the second bottom wall in the first direction is longer than the sum of the length of the switch in the first direction, the length of the first cylindrical portion in the first direction, and the length of the second cylindrical portion in the first direction.

8. a second internal tube having one end connected to the tank and through which the ink flows out of the tank; a second fluid interface connected to the other end of the second inner tube; The tank unit according to claim 5 , wherein the second fluid interface is located inside an opening formed in the fourth side wall and penetrating in the second direction.

9. a second internal wiring having one end connected to the substrate; a second electrical interface to which the other end of the second internal wiring is connected, The tank unit according to claim 8 , wherein the second electrical interface is located inside the opening in the fourth side wall.

10. the first electrical interface and the first fluid interface project downwardly from the opening in the second bottom wall; The tank unit according to any one of claims 5 to 9, wherein the first electrical interface and the first fluid interface are aligned in the second direction.

11. an atmosphere communication passage extending upward from the tank and having a valve for releasing pressure in the tank to the atmosphere; a purge pump provided in the atmosphere communication passage; a reinforcing frame disposed above the second bottom wall and extending in the first direction and the second direction, 9. The tank unit according to claim 8, wherein the purge pump is located on an upper surface of the reinforcement frame and is located, in the first direction, between an end of the second bottom wall on one side in the first direction and the atmosphere communication flow path.

12. The second bottom wall is further formed with another opening passing through in the vertical direction, one end of the atmosphere communication passage is connected to the tank, The tank unit according to claim 11 , wherein the other end of the atmosphere communication passage is connected to the other opening of the second bottom wall.

13. The tank unit according to claim 9 , wherein the substrate extends in the first direction and the vertical direction, and is located between the tank and the third side wall in the second direction.

14. a head unit having a head in which nozzles are formed; A head system comprising: a tank unit according to any one of claims 1 to 13, connected to the head unit and configured to supply ink to the head unit.

15. An ink supply device; 14. An ink supply system comprising: the tank unit according to claim 1, which is connected to the ink supply machine and is configured to receive ink from the ink supply machine.

16. a head unit having a head in which nozzles are formed; The tank unit according to any one of claims 1 to 13, which is connected to the head unit and configured to supply ink to the head unit; an ink supply unit connected to the tank unit and configured to supply the ink to the tank unit.

17. transporting the print medium by a conveyor; A printing method comprising: ejecting ink from the head system according to claim 14 or the printing system according to claim 16 onto a printing medium transported by a conveyor.

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