Patent Description:
Conventionally, there is known an ink-jet printer provided with a controller, a print driving part electrically connected to the controller, and a print head electrically connected to the print driving part. For example, in an ink-jet printer disclosed in Japanese Patent Application Laid-Open No. <CIT>, the controller and the print driving part are connected by a cable, and the print driving part and the print head are connected by another cable.

In the ink-jet printer disclosed in Japanese Patent Application Laid-Open No. <CIT>, a direction in which the cable connecting the controller and the print driving part extends crosses a direction in which the another cable connecting the print driving part and the print head extends. Due to this, in a case of installing or arranging the print driving part, it is necessary to secure not only a space for the print driving part, but also a space in each of the direction in which one of the cables extends, which in turn leads to such a problem that a placement (arrangement) location of the print driving part is restricted.

The present invention has been made in view of the above-described problems, and an object of the present invention is to improve the degree of freedom of the placement location of a tank unit relaying a head unit and a base unit. Further, another object of the present invention is to provide a head system, an ink supplying system, a printing system and a printing method each provided with such a tank unit.

According to a first aspect of the present invention, there is provided a tank unit including:.

According to a second aspect of the present invention, there is provided a head system including:.

According to a third aspect of the present invention, there is provided an ink supplying system including:.

According to a fourth aspect of the present invention, there is provided a printing system including:.

According to a fifth aspect of the present invention, there is provided a printing method including:.

According to the first to fifth aspects of the present invention, it is possible to provide a tank unit of which degree of freedom of the placement location is improved, and to provide a head system, an ink supplying system, a printing system and a printing method each provided with such a tank unit.

In the following, an explanation will be given about an embodiment of a printing system according to the present invention, with an ink-jet printer as an example.

First, the overview of an ink-jet printer <NUM> will be explained, with reference to <FIG>. Note that in the following explanation, a direction from a far side toward a front side of the sheet surface in <FIG> is referred to as an x direction, a direction from the left side toward the right side of the sheet surface is referred to as a y direction, and a direction from the lower side toward the upper side of the sheet surface is referred to as a z direction. Namely, the x direction and the y direction are along a horizontal plane and are orthogonal to each other. The z direction is along the vertical direction and is orthogonal to the x direction and the y direction. Further, in each of the drawings, a side of a forward (tip) end of an arrow indicating the x direction is referred to as one side in the x direction, and a side of a base end of the arrow indicating the x direction is referred to as the other side of the x direction in some cases. A side of a forward end of an arrow indicating the y direction is referred to as one side in the y direction, and a side of a base end of the arrow indicating the y direction is referred to as the other side of the y direction in some cases. Further, a side of a forward end of an arrow indicating the z direction is referred to as one side in the z direction, and a side of a base end of the arrow indicating the z direction is referred to as the other side of the z direction in some cases.

As depicted in <FIG>, the ink-jet printer <NUM> is mainly provided with a base unit <NUM>, a tank unit <NUM>, a head unit <NUM> and an operation panel <NUM>. The base unit <NUM> and the tank unit <NUM> are connected by a tube T1 as an ink channel and a wiring cable C1. The tank unit <NUM> and the head unit <NUM> are connected by tubes T2 and T3 as the ink channel and a wiring cable C2. The operation panel <NUM> and the base unit <NUM> are connected by a wiring cable C3. The base unit <NUM>, the tank unit <NUM>, the head unit <NUM> and the operation panel <NUM> are fixed to a rack R to thereby have a relative positional relationship determined therefor.

The base unit <NUM> functions as an ink supplying device configured to supply an ink to the tank unit <NUM> via the tube T1. The tank unit <NUM> functions as a relaying device configured to supply the ink supplied from the base unit <NUM> to the head unit <NUM> via the tubes T2 and T3. Namely, the base unit <NUM> and the tank unit <NUM> function as an ink supplying system configured to supply the ink to the head unit <NUM>. Further, the tank unit <NUM> and the head unit <NUM> function as a head system to which the ink is supplied from the base unit <NUM>. The head unit <NUM> is provided with an ink-jet head <NUM>, and a plurality of nozzles are formed in an ink discharge surface 42a of the ink-jet head <NUM>. The ink-jet head <NUM> is configured to discharge or eject the ink, supplied from the tank unit <NUM>, from the plurality of nozzles formed in the ink discharge surface 42a. As the ink-jet head <NUM>, it is allowable to use, for example, a so-called piezoelectric ink-jet head provided with a plurality of nozzles, a plurality of individual channels each of which communicates with one of the plurality of nozzles, and a plurality of piezoelectric elements each of which applies a discharge pressure to the ink inside one of the plurality of individual channels.

In the present embodiment, the head unit <NUM> is configured to be attachable with respect to the rack R in a horizontal posture or a vertical posture. Here, the horizontal posture is a posture, as depicted in <FIG>, wherein the ink discharge surface 42a of the ink-jet head <NUM> is orthogonal to the y direction. In the horizontal posture, the ink is discharged from the ink discharge surface 42a in a horizontal direction (a direction opposite to the y direction). On the other hand, the vertical posture is a posture, as depicted in <FIG>, wherein the ink discharge surface 42a of the ink-jet head <NUM> is orthogonal to the z direction. In the vertical posture, the ink is discharged from the ink discharge surface 42a vertically downward (a direction opposite to the z direction). Here, it is presumed that a print medium M is conveyed in the x direction by a conveyor CV, as depicted in <FIG>. In such a case, as depicted in <FIG>, by attaching the head unit <NUM> to the rack R in the horizontal posture, it is possible to perform printing on a side surface (side surface orthogonal to the horizontal plane) of the print medium M. On the other hand, by attaching the head unit <NUM> to the rack R in the vertical posture as depicted in <FIG>, it is possible to perform printing on an upper surface of the print medium M.

Next, an ink supply system of the ink-jet printer <NUM> will explained. As depicted in <FIG>, the base unit <NUM> is provided with a main tank <NUM> and a pump <NUM>. The main tank <NUM> is installed inside the base unit <NUM>. The main tank <NUM> is provided, for example, with a liquid level sensor 22a of a float type which is configured to detect the water level of the ink inside the main tank <NUM>. Further, an atmosphere communicating hole is formed in the main tank <NUM>, and the inside of the main tank <NUM> communicates with the atmosphere via the atmosphere communicating hole. Note that in the present embodiment, although the main tank <NUM> is installed inside the base unit <NUM>, the main tank <NUM> may be configured to be detachable from the base unit <NUM> and exchangeable. Alternatively, it is also allowable to separately provide an exchangeable ink tank configured to communicate with the main tank <NUM> and to supply the ink to the main tank <NUM>.

The tank unit <NUM> is provided with a head tank <NUM>, a circulation pump <NUM>, a purge pump <NUM>, a solenoid valve <NUM> and an atmosphere communicating channel <NUM>. The head tank <NUM> is installed inside the tank unit <NUM>. The head tank <NUM> is provided, for example, with a liquid level sensor 32a of a float type which is configured to detect the water level of the ink inside the head tank <NUM>. The atmosphere communicating channel <NUM> is provided with the purge pump <NUM> and the solenoid valve <NUM>. Although the solenoid valve <NUM> normally allows the head tank <NUM> to communicate with the atmosphere, the solenoid valve <NUM> shuts off the communication between the head tank <NUM> and the atmosphere during a purge processing (to be described later on), and allows the head tank <NUM> and the purge pump <NUM> to communicate with each other. Accordingly, the head tank <NUM> communicates with the atmosphere, except for a period of time during which the purge processing is being executed.

The head unit <NUM> is provided with the ink-jet head <NUM> and a damper <NUM>. The damper <NUM> is provided, for example, in order to mitigate any variation in pressure in the ink inside the ink-jet head <NUM> which occurs, for example, in such a case that a print medium conveyed by the conveyor skews and collides against the ink-jet head <NUM>, etc..

The main tank <NUM> and the head tank <NUM> communicate 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 <NUM>, and the other end of the tube T0 is connected to the pump <NUM>. One end of the tube T1 is connected to the pump <NUM>, and the other end of the tube T1 is connected to a coupler CP1 of the tank unit <NUM>. Further, one end of the tube IT1 is connected to the coupler CP1 of the tank unit <NUM>, and the other end of the tube IT1 is connected to the head tank <NUM>.

The head tank <NUM> and the damper <NUM> of the head unit <NUM> communicate with each other via a tube IT2 and a tube T2. One end of the tube IT2 is connected to the head tank <NUM>, and the other end of the tube IT2 is connected to a coupler CP2 of the tank unit <NUM>. Further, one end of the tube T2 is connected to the coupler CP2 of the tank unit <NUM> and the other end of the tube T2 is connected to the damper <NUM>.

The damper <NUM> and the ink-jet head <NUM> of the head unit <NUM> communicate with each other via a tube T4. Namely, one end of the tube T4 is connected to the damper <NUM> and the other end of the tube T4 is connected to the ink-jet head <NUM>. Further, the ink-jet head <NUM> and the head tank <NUM> communicate with each other via a tube T3, a tube IT4 and a tube IT3. One end of the tube T3 is connected to the ink-jet head <NUM>, and the other end of the tube T3 is connected to a coupler CP3 of the tank unit <NUM>. One end of the tube IT4 is connected to the coupler CP3 of the tank unit <NUM>, and the other end of the tube IT4 is connected to the circulation pump <NUM> of the tank unit <NUM>. Further, one end of the tube IT3 is connected to the circulation pump <NUM> of the tank unit <NUM>, and the other end of the tube IT3 is connected to the head tank <NUM>.

At a time of initially introducing (installing) the ink-jet printer <NUM>, the ink is not present inside the head tank <NUM> and inside the ink-jet head <NUM>. Accordingly, at first, a controller <NUM> (to be described later on, see <FIG>) drives the pump <NUM> so as to supply the ink from the main tank <NUM> to the head tank <NUM> via the tubes T0, T1 and IT1. Further, in a case that the liquid level sensor 32a of the head tank <NUM> detects that the water level of the ink inside the head tank <NUM> has reached an upper limit, the controller <NUM> stopes the pump <NUM>. With this, the supply of the ink to the head tank <NUM> is stopped. Next, in a state that the ink discharge surface 42a of the ink-jet head <NUM> is covered by a non-illustrated cap, the controller <NUM> drives the circulation pump <NUM> via a relay substrate <NUM> (to be described later on; see <FIG>) of the tank unit <NUM>. With this, the ink flows in an order of: the tube IT2, the tube T2, the tube T4, the ink-jet head <NUM>, the tube T3, the tube IT4, and the tube IT3, whereby the ink is filled in the ink-jet head <NUM> and in a channel connecting the ink-jet head <NUM> and the head tank <NUM>. In a case that the ink is filled in the ink-jet head <NUM> and in the channel connecting the ink-jet head <NUM> and the head tank <NUM>, the controller <NUM> stopes the circulation pump <NUM> via the relay substrate <NUM>. With this, the supply of the ink to the ink-jet head <NUM> is stopped.

In a case that the ink is discharged or ejected from the ink-jet head <NUM> in a state that the ink is filled in the ink-jet head <NUM> and in the channel connecting the ink-jet head <NUM> and the head tank <NUM>, an amount, of the ink, which is same as the amount of the ink discharged from the ink-jet head <NUM> is supplied from the head tank <NUM> to the ink-jet head <NUM> via the tubes IT2, T2 and T4. Then, in a case that the ink inside the head tank <NUM> is decreased by continuous discharge of the ink from the ink-jet head <NUM> and that the liquid level sensor 32a of the head tank <NUM> detects that the water level of the ink inside the head tank <NUM> has reached a lower limit, the controller <NUM> drives the pump <NUM>. With this, the ink is supplied from the main tank <NUM> to the head tank <NUM> via the tubes T0, T1 and IT1. In a case that the ink inside the main tank <NUM> is decreased by supplying of the ink to the head tank <NUM> and that the liquid level sensor 22a of the main tank <NUM> detects that the water level of the ink inside the main tank <NUM> has reached a lower limit, the controller <NUM> causes, for example, the operation panel <NUM> to display a message urging replenishing of the ink with respect to the main tank <NUM>. Then, a user, who has seen the message urging the replenishing of the ink with respect to the main tank <NUM> replenishes the main tank <NUM> with the ink, thereby making it possible to supply the ink from the main tank <NUM> to the head tank <NUM> again.

Note that in the present embodiment, in order to exhaust (discharge), from the plurality of nozzles of the ink discharge surface 42a, a viscous ink inside the ink-jet head <NUM>, or an air bubble entered into and mixed with the ink inside the ink-jet head <NUM> and inside the tubes IT2, T2 and T4, the controller <NUM> executes, in some cases, a purge processing of forcibly supplying the ink from the head tank <NUM> to the ink-jet head <NUM>. In the purge processing, the controller <NUM> controls the solenoid valve <NUM> so as to shut off the communication between the head tank <NUM> and the atmosphere and to allow the head tank <NUM> to communicate with the pure pump <NUM>. Further, the control <NUM> drives the purge pump <NUM> via the relay substrate <NUM> in this state, to thereby make the pressure inside the head tank <NUM> to be in the positive pressure. By doing so, the ink is forcibly supplied from the head tank <NUM> to the ink-jet head <NUM> via the tube IT2, T2 and T4, thereby exhausting the viscous ink and/or the air bubble inside the ink-jet head <NUM> from the plurality of nozzles.

Next, an explanation will be given about the electric connecting relationship among the base unit <NUM>, the tank unit <NUM>, the head unit <NUM> and the operation panel <NUM>. As depicted in <FIG>, the base unit <NUM> is provided with the controller <NUM>; the controller <NUM> is electrically connected to the liquid level sensor 22a and the pump <NUM>. Further, the controller <NUM> is electrically connected to the operation panel <NUM> as an input-output interface with respect to a user. The tank unit <NUM> is provided with the relay substrate <NUM>; the relay substrate <NUM> is electrically connected to the liquid level sensor 32a, the circulation pump <NUM>, the purge pump <NUM> and the solenoid valve <NUM>. Further, the relay substrate <NUM> is electrically connected to the controller <NUM> of the base unit <NUM> via a wiring cable W1 and the wiring cable C1. One end of the wiring cable W1 is connected to the relay substrate <NUM>, and the other end of the wiring cable W1 is connected to a connector CN1 of the tank unit <NUM>. Further, one end of the wiring cable C1 is connected to the connector C1 of the tank unit <NUM>, and the other end of the wiring cable CN1 is connected to the controller <NUM>. The head unit <NUM> is provided with a driving substrate <NUM>; the driving substrate <NUM> is electrically connected to ink-jet head <NUM>. Further, the relay substrate <NUM> of the tank unit <NUM> and the driving substrate <NUM> are electrically connected to each other via a wiring cable W2 and the wiring cable C2. One end of the wiring cable W2 is connected to the relay substrate <NUM>, and the other end of the wiring cable W2 is connected to a connector CN2 of the tank unit <NUM>. Further, one end of the wiring cable C2 is connected to the connector CN2 of the tank unit <NUM>, and the other end of the wiring cable C2 is connected to the driving substrate <NUM>.

The controller <NUM> is provided with a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory) and an ASIC (Application Specific Integrated Circuit) which includes a variety of kinds of control circuits, etc. The controller <NUM> executes a variety of kinds of processing in accordance with a program stored in the ROM and by the CPU and the ASIC. For example, the controller <NUM> generates a control signal based on a print job received from an external apparatus <NUM> such as a PC, etc., and transmits the control signal to the driving substrate <NUM> via the relay substrate <NUM>. Further, the driving substrate <NUM> generates a driving signal based on the control signal, and drives the ink-jet head <NUM> based on the driving signal, thereby executing a print processing of printing an image, etc., on the print medium M. Furthermore, the controller <NUM> controls the pumps <NUM> and <NUM>, the purge pump <NUM>, the solenoid valve <NUM>, the operation panel <NUM>, etc., based on signals each of which is outputted from one of the liquid level sensors 22a and 32a, thereby executing a supply processing of the ink and a maintenance processing with respect to the ink-jet head <NUM>. Note that although the example in which the controller <NUM> performs the print processing by the CPU and the ASIC has been explained, the present invention is not limited to or restricted by this. It is allowable to realize the controller <NUM> by any hardware configuration. For example, it is allowable that the processing is executed by the CPU only or the ASIC only. Alternatively, it is allowable to realize the function of the controller <NUM> in a divided manner by two or more pieces of the CPU and/or two or more pieces of the ASIC.

Next, the details of the tank unit <NUM> will be explained, with reference to <FIG>. As depicted in <FIG>, the tank unit <NUM> 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 <NUM>, a side wall <NUM> and an upper wall 30i. Note that in <FIG>, in order to depict the internal configuration of the tank unit <NUM>, the upper wall 30i, the inclined wall 30f, the side wall 30e and the side wall <NUM> are omitted from the illustration. Further, in <FIG>, in order to depict the internal configuration of the tank unit <NUM>, the side wall 30e and the inclined wall 30f are omitted from the illustration.

The bottom walls 30a, 30b and the upper wall 30i each have a rectangular outer shape spreading or expanding in the x direction and the y direction. The bottom wall 30b is positioned on the one side in the z direction with respect to the bottom wall 30a (the upper side in <FIG>), and the upper wall 30i is positioned on the one side in the z direction with respect to the bottom wall 30b.

The side wall 30c has a rectangular outer shape spreading in the y direction and the z direction. An end part on the one side in the z direction (the upper side in <FIG>) of the side wall 30c is connected to an end part on the one side in the x direction (the left side in <FIG>) of the bottom wall 30b. An end part on the other side in the z direction (the lower side in <FIG>) of the side wall 30c is connected to an end part on the other side in the x direction (the right side in <FIG>) of the bottom wall 30a.

The side walls 30d and <NUM> each have a pentagonal shape which are parallel to a yz plane. An end part on the other side in the z direction (the lower side in <FIG>) of the side wall 30d is connected to an end part on the other side in the x direction of the bottom wall 30b. An end part on the one side in the z direction of the side wall 30d is connected to an end part on the other side in the x direction of the upper wall 30i. An end part on the other side in the z direction (the lower side in <FIG>) of the side wall <NUM> is connected to an end part on the one side in the x direction of the bottom wall 30a. An end part on the one side in the z direction of the side wall <NUM> is connected to an end part on the one side in the x direction of the upper wall 30i.

The side walls 30e and <NUM> each have a hexagonal outer shape spreading in the x direction and the z direction. The side wall 30e is connected to the bottom walls 30a and 30b, an end part on the one side in the y direction (the front side in <FIG>) of the side wall 30c, and a part, of an end part on the one side in the y direction of each of the side walls 30d and <NUM>, which is parallel to the z direction. The side wall <NUM> is connected to an end part in the other side in the y direction (the far (rear) side in <FIG>) of each of the bottom walls 30a and 30b, and an end part on the other side in the y direction of each of the side walls 30c, 30d and <NUM>.

The inclined wall 30f has a rectangular outer shape, and is inclined with respect to the plane spreading in the x direction and the z direction. The inclined wall 30f is connected to an end part on the one side in the z direction of the side wall 30e, an end part on the one side in the y direction of the upper wall 30i, an inclined part, of an end part on the one side in the y direction of the side wall 30d, which is inclined with respect to the z direction, and an inclined part, of an end part on the one side in the y direction of the side wall <NUM>, which is inclined with respect to the z direction.

As depicted in <FIG>, the head tank <NUM>, the relay substrate <NUM> and the circulation pump <NUM> are arranged on a surface on the one side in the z direction of the bottom wall 30a. The tubes IT1 and IT2 (see <FIG>) and the tube IT3 (see <FIG>) are connected to the head tank <NUM>. Further, an end of the atmosphere communicating channel <NUM> (see <FIG>) which extends in the z direction is connected to an end part on the one side in the z direction of the head tank <NUM>, and the other end of the atmosphere communicating channel <NUM> is connected to an another opening which is formed in the bottom wall 30b and which is different from openings OP1 and OP2. The relay substrate <NUM> has a rectangular outer shape spreading in the x direction and the z direction, and is positioned, in the y direction, between the head tank <NUM> and the side wall 30e. Further, the circulation pump <NUM> is also positioned, in the y direction, between the head tank <NUM> and the side wall 30e.

As depicted in <FIG>, the two openings OP1 and OP2 penetrating the bottom wall 30b in the z direction are formed in the bottom wall 30b. The coupler CP1 is positioned inside the opening OP1. One end of the coupler CP1 protrudes from the opening OP1 in the direction opposite to the z direction. The tube T1 is connected to the one end of the coupler CP1. Furter, as depicted in <FIG>, the tube IT1 is connected to the other end of the coupler CP1. The connector CN1 is positioned inside the opening CP2. As depicted in <FIG>, one end of the connector CN1 protrudes in the direction opposite to the z direction. The wiring cable C1 is connected to the one end of the connector CN1. Furter, the wiring cable W1 (see <FIG>) is connected to the other end of the connector CN1. As depicted in <FIG> and <FIG>, the coupler CP1 and the connector CN1 are arranged side by side in the y direction. Furthermore, as depicted in <FIG>, a length h1 in the z direction of the side wall 30c, in other words, a spacing 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 connectable to the one end of the coupler CP1, and is greater than the minimum bending radius of the wiring cable C1 connectable to the one end of the connector CN1.

As depicted in <FIG>, in the wide wall 30d, end parts of cylindrical parts P1 to P4, respectively, which extend in the x direction from the side wall 30d are opened. In other words, the four openings and the four cylindrical parts P1 to P4 extending from the four openings, respectively, in the x direction are formed in the side wall 30d. A female screw is formed inside each of the four cylindrical parts P1 to P4, and a male screw configured to fix the tank unit <NUM> to the rack R is inserted into each of the four cylindrical parts P1 to P4. As depicted in <FIG>, a length in the x direction of each of the four cylindrical parts P1 to P4 is shorter than a length d1 in the x direction of the bottom wall 30b (see <FIG>). 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 parts P1 to P4. Further, a length h2 in the z direction of the side wall 30d (see <FIG>), in other words, a spacing distance in the z direction from the bottom wall 30b to the upper wall 30i, is greater than the minimum bending radius of the tube IT1 connected to the other end of the coupler CP1.

As depicted in <FIG>, a purge switch PS is provided, in the inclined wall 30f, on an area thereof on the one side in the z direction with respect to the bottom wall 30b, in other words, on the area overlapping with the bottom wall 30b in the z direction. In a case that the user presses or pushes the purge switch PS, the purge processing as described above is executed. Note that as depicted in <FIG> and <FIG>, a length in the x direction of the purge switch PS is shorter than the length d1 in the x direction of the bottom wall 30b. 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 the purge switch PS. Further, as depicted in <FIG>, the length d1 in the x direction of the bottom wall 30b is longer than a sum of the length in the x direction of the cylindrical part P1 and the length in the x direction of the purge switch PS, and is longer than a sum of the length in the x direction of the cylindrical part P2 and the length in the x direction of the purge switch PS.

As depicted in <FIG> and <FIG>, an opening OP3 is formed in the side wall <NUM>. Further, the couplers CP2 and CP3 (see <FIG>) and the connector CN2 (see <FIG>) are provided inside the opening OP3. The tube IT2 (see <FIG>) is connected to one end of the coupler CP2, and the tube T2 (see <FIG>) is connected to the other end of the coupler CP2. The tube IT4 (see <FIG>) is connected to one end of the coupler CP3, and the tube T3 (see <FIG>) is connected to the other end of the coupler CP3. Further, the wiring cable W2 (see <FIG>) is connected to one end of the connector CN2, and the wiring cable C2 (see <FIG>) is connected to the other end of the connector CN2.

As depicted In <FIG>, a reinforcing frame FR spreading in the x direction and the y direction is provided inside the tank unit <NUM>. As depicted in <FIG>, a cylindrical part P5 extending in the z direction is formed in the bottom wall 30b; the reinforcing frame FR is fixed to the one side in the z direction with respect to the head tank <NUM>, by a screw inserted into the inside of the cylindrical part P5. Further, as depicted in <FIG>, the purge pump <NUM>, the solenoid valve <NUM>, etc., are arranged on a surface on the one side in the z direction of the reinforcing frame FR. The purge pump <NUM> is positioned, in the x direction, between an end part on the one side in the x direction of the bottom wall 30b and the atmosphere communicating channel <NUM> (see <FIG>) extending in the z direction. Furthermore, as depicted in <FIG>, the length d1 in the x direction of the bottom wall 30b is longer than a sum of the length in the x direction of the cylindrical part P1, the length in the x direction of the purge switch PS and a length in the x direction of the cylindrical part P5, and is longer than a sum of a length in the x direction of the cylindrical part P2, the length in the x direction of the purge switch PS and the length in the x direction of the cylindrical part P5.

In the tank unit <NUM> of the present embodiment as explained above, the x direction, the y direction and the z direction are examples, respectively, of a "first direction", a "second direction" and a "vertical direction". The bottom wall 30a and the bottom wall 30b are examples, respectively, of a "first bottom wall" and a "second bottom wall". The side wall 30c and the side wall 30d are examples, respectively, of a "first side wall" and a "second side wall". The side wall 30e and the inclined wall 30f are an example of a "third side wall", and the side wall <NUM> is an example of a "fourth side wall". The head tank <NUM> is an example of a "tank", and the relay substrate <NUM> is an example of a "substrate". The tubes IT1, T1 and IT2 are examples, respectively, of a "first internal tube", a "first external tube" and a "second internal tube", and the coupler CP1 and CP2 are examples, respectively, of a "first fluidic interface" and a "second fluidic interface". The wiring cables W1, C1 and W2 are examples, respectively, of a "first internal wiring", a "first external wiring" and a "second internal wiring", and the connectors CN1 and CN2 are examples, respectively, of a "first electric interface" and a "second electric interface". The cylindrical parts P1 to P4 are an example of a "first cylindrical part" and the cylindrical part P5 is an example of a "second cylindrical part".

In the tank unit <NUM> as explained above, the one end of the coupler CP1 and the one end of the connector CN1 protrude, respectively, from the opening OP1 and the opening OP2 of the bottom wall 30b to the other side in the z direction, and the tube T1 and the wiring cable C1 are connected, respectively, to the one end of the coupler CP1 and the one end of the connector CN1. Further, the length h1 in the z direction of the side wall 30c, in other words, the spacing distance between the bottom wall 30a and the bottom wall 30b is greater than the minimum bending radius of the tube T1 connected to the one end of the coupler CP1, and is greater than the minimum bending radius of the wiring cable C1 connected to the one end of the connector CN1. Accordingly, for example, even in such a case that the tank unit <NUM> is arranged in a state that the bottom wall 30a is placed on the horizontal plane, it is possible to route, along the horizontal plane, the tube T1 and the wiring cable C1 extending, respectively, from the coupler CP1 and the connector CN1 to the other side in the z direction, while bending the tube T1 and the wiring cable C1 without breaking or damaging the tube T1 and the writing cable C1. Namely, it is possible to improve the degree of freedom of the placement location of the tank unit <NUM>.

Further, for example, depending on the placement location of the tank unit <NUM>, such a case is conceivable that any obstacle such as a wall, etc., is present on the other side in the x direction with respect to the tank unit <NUM>. Alternatively, such a case is conceivable that, in a state that a jig, etc., is placed with respect to the side wall 30d of the tank unit <NUM>, a screw is inserted into any one of the cylindrical parts P1 to P4 to thereby fix the tank unit <NUM> to the jig. In either of the above-described cases, the user is unable to access the coupler CP1 and the connector CN1 from the other side in the x direction. In view of this, in the present embodiment, the one end of the coupler CP1 and the one end of the connector CN1 protrude, respectively, from the opening OP1 and the opening OP2 of the bottom wall 30b to the other side in the z direction. Accordingly, even in the above-described case that the user is unable to access the coupler CP1 and the connector CN1 from the other side in the x direction, the user is able to access the coupler CP1 and the connector CN1 from the one side in the y direction or from the other side in the y direction, and to connect the tube T1 and the wiring cable C1, respectively, to the coupler CP1 and the coupler CP2. Furthermore, even in a case that any space for routing the tube T1 and/or the wiring cable C1 is not present on the other side in the x direction with respect to the side wall 30d of the tank unit <NUM> due to such a restriction in the placement location, it is possible to route the tube T1 and/or the wiring cable C1 along the yz plane. Namely, it is possible to improve the degree of freedom of the placement location of the tank unit <NUM>.

Furthermore, the other end of the coupler CP1 is positioned on the one side in the z direction from (with respect to) the bottom wall 30b, and the length h2 in the z direction of the side wall 30d, in other words, the spacing distance from the bottom wall 30b to the upper wall 30i is greater than the minimum bending radius of the tube IT1 connected to the other end of the coupler CP1. Accordingly, it is possible to route the tube IT1 inside the tank unit <NUM>, while bending the tube IT1 without breaking or damaging the tube IT1.

In the tank unit <NUM> of the present embodiment, it is possible to suppress the size in the z direction of the tank unit <NUM> to be minimally required, by suppressing the length h2 in the z direction of the side wall 30d to be minimally required within a range which is greater than the minimum bending radius of the tube IT1, while suppressing the length h1 in the z direction of the side wall 30c within a range greater than the minimum bending radius of the tube T1 and the minimum bending radius of the wiring cable C1.

Further, in the tank unit <NUM> of the present embodiment, it is possible to suppress the size in the z direction of the tank unit <NUM> to be minimally required, by suppressing the length d1 in the x direction of the bottom wall 30b within a range longer than the sum of the length in the x direction of the cylindrical part P1, the length in the x direction of the purge switch PS and the length in the x direction of the cylindrical part P5.

In the tank unit <NUM> of the present embodiment, the coupler CP1 and the connector CN1 are arranged side by side in the y direction in the bottom wall 30b. Accordingly, it is possible to suppress the size in the x direction of the bottom wall 30b to be minimally required, which in turn makes it possible to suppress the size in the x direction of the tank unit <NUM> to be minimally required, as a result.

Inside the tank unit <NUM> of the present embodiment, the reinforcing frame FR is provided on the one side in the z direction with respect to the head tank <NUM>. Further, the purge pump <NUM> is arranged in the surface, of the reinforcing frame FR, which is on the one side in the z direction; the purge pump <NUM> is positioned, in the x direction, between the end part on the one side in the x direction of the bottom wall 30b and the atmosphere communicating channel <NUM> extending to the one side in the z direction. With this, it is possible to effectively use the space which is inside the tank unit <NUM> and which is on the one side in the z direction with respect to the head tank <NUM>, thereby making it possible suppress any increase in the size of the tank unit <NUM>.

Although the embodiment of the present invention has been explained in the foregoing, the present invention is not limited to or restricted by the above-described embodiment, and various design changes can be made within the scope of the claims.

In the above-described embodiment, the openings OP1 and OP2 are formed in the bottom wall 30b, and the one end of the coupler CP1 protrudes from the opening OP1, and the one end of the connector CN1 protrudes from the opening OP2. The present invention, however, is not limited to or restricted by this. For example, it is allowable that the one end of the coupler CP1 and the one end of the connector CN1 protrude from one opening formed in the bottom wall 30b. Alternatively, it is allowable that the other end of the atmosphere communicating channel <NUM> is connected to the one opening.

In the above-described embodiment, the coupler CP1 and the connector CN1 are arranged side by side in the y direction in the bottom wall 30b. The present invention, however, is not limited to this. For example, in a case that wall, etc., is present on the other side in the x direction with respect to the tank unit <NUM>, and that the user accesses the coupler CP1 and the connector CN1 from the one side in the y direction or from the other side in the y direction so as to connect the tube T1 and the wiring cabler C1, respectively, to the coupler CP1 and the connector CN1, it is allowable to arrange the coupler CP1 and the connector CN1 to be shifted from each other in the x direction. By doing so, the user is allowed to access the coupler CP1 and the connector CN1 more easily.

Claim 1:
A tank unit (<NUM>) comprising:
a first bottom wall (30a) spreading in a first direction and a second direction, the first direction being along a horizontal plane, the second direction being along the horizontal plane and crossing the first direction;
a second bottom wall (30b) spreading in the first direction and the second direction, the second bottom wall defining an opening (OP1, OP2) penetrating therethrough in a vertical direction;
a first side wall (30c) spreading in the vertical direction and the second direction, the first side wall having an upper end part and a lower end part, the upper end part being connected to an end part on one side in the first direction of the second bottom wall (30b), the lower end part being connected to an end part on the other side in the first direction of the first bottom wall (30a);
characterized in that:
the second bottom wall (30b) is positioned above the first bottom wall (30a); and
the tank unit (<NUM>) further comprises:
a tank (<NUM>) arranged on an upper surface of the first bottom wall (30a) and which is configured to store ink;
a liquid level sensor (32a) configured to detect a liquid level of the ink inside the tank (<NUM>);
a substrate (<NUM>) electrically connected to the liquid level sensor (32a);
a first internal wiring (W1) having one end connected to the substrate (<NUM>);
a first internal tube (IT1) which has one end connected to the tank (<NUM>) and through which the ink to be supplied to the tank flows;
a first electric interface (CN1) which is positioned inside the opening (OP2) of the second bottom wall (30b) and to which the other end of the first internal wiring (W1) is connected; and
a first fluidic interface (CP1) which is positioned inside the opening (OP1) of the second bottom wall (30b) and to which the other end of the first internal tube (IT1) is connected.