Patent Description:
Conventionally, there is known an ink-jet printer provided with an ink supplying unit and a head unit which is connected to the ink supplying unit by an ink channel such as a tube, etc. For example, in an ink-jet printer disclosed in Japanese Patent Application Laid-Open No. <CIT>, an ink discharge surface (ink ejection surface) of a head unit is provided perpendicularly or vertically so as to perform printing on a side surface (vertical surface) of an object of printing. Further, an end of the ink channel is connected to a surface (vertical surface), of the head unit, which is on the opposite side to the ink discharge surface.

Here, in a case that printing is to be performed on an upper surface of the object of printing by the ink-jet printer disclosed in Japanese Patent Application Laid-Open No. <CIT>, it is necessary to orient the ink discharge surface downwardly. In a state that the ink discharge surface is oriented downwardly, since the side surface, which is on the opposite side to the ink discharge surface, namely the side surface to which the one end of the ink channel is connected, is oriented upwardly, a part of the ink channel projects or protrudes upward to a location above the head unit. Due to this, a certain space is required at the location above the head unit, which in turn leads to such a problem that a placement (arrangement) posture or a placement location of the head unit is restricted. Further, there arises also such a problem that the length of the ink channel is required to be made long because the part of the ink channel protrudes upwardly to the location above the head unit.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a head unit, a printing system and a printing method each of which is capable of improving the degree of freedom of the placement posture and placement location of the head unit, while maintaining the length of the ink channel connecting the ink supplying unit and the head unit at a predetermined length.

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

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

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

According to the first to third aspects of the present invention, it is possible to improve the degree of freedom of the placement posture and placement location of the head unit, while maintaining the length of the ink channel connecting the ink supplying unit and the head unit at a predetermined length.

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 surface detecting 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 surface detecting 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 surface detecting 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 surface detecting 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 surface detecting 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 controller drives the purge pump <NUM> via the relay substate <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 surface detecting 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 surface detecting 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 surface detecting 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 which is parallel to a plane 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 tube IT1, the tubes IT1 and IT2 (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 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 on the inside of 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 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.

Next, the details of the head unit <NUM> will be explained, with reference to <FIG>. As depicted in <FIG>, the head unit <NUM> is provided with the ink-jet head <NUM>, a casing <NUM>, an edge member <NUM> and a guide bracket <NUM>. The ink discharge surface 42a of the ink-jet head <NUM> has a rectangular outer shape which is elongated in the z direction. Further, the nozzle row NR is formed, in the ink discharging surfacer 42a, by the plurality of nozzles aligned in the z direction. Namely, the nozzle row NR is formed along the z direction. Note that the illustration of the guide bracket <NUM> is omitted in <FIG>.

The casing <NUM> includes a frame <NUM> depicted in <FIG>, inside the casing <NUM>; the driving substrate <NUM>, the ink-jet head <NUM>, the damper <NUM> are supported by the frame <NUM>. As depicted in <FIG>, the casing <NUM> has a side surface 44a on the one side in the y direction, a side surface 44b on the one side in the z direction, and a side surface 44c on the one side in the x direction. The side surface 44a spreads in the x direction and the z direction. The side surface 44b spreads in the x direction and the y direction. The side surface 44c spreads in the y direction and the z direction. Further, the edge member <NUM> which is detachably attachable with respect to the casing <NUM> is attached to a part, of the casing <NUM>, to which the side surface 44a and the side surface 44b are connected.

As depicted in <FIG>, the edge member <NUM> defines an opening OP4 through which the tubes T2 and T3 and the wiring cable C2 extending from the tank unit <NUM> are inserted into the head unit <NUM>. The edge member <NUM> is attachable, with respect to the casing <NUM>, selectively in a first state in which the opening OP4 faces (is oriented) in the y direction (the state in <FIG>) and a second state in which the opening OP4 faces in the z direction (the state in <FIG>). In a case that the head unit <NUM> is to be attached to the rack R in the horizontal posture depicted in <FIG>, the edge member <NUM> is attached to the casing <NUM> in the first state, thereby making it possible to route the tubes T2 and T3 and the wiring cable C2 without using a space on the one side in the z direction with respect to the head unit <NUM>. On the other hand, in a case that the head unit <NUM> is to be attached to the rack R in the vertical posture depicted in <FIG>, the edge member <NUM> is attached to the casing <NUM> in the second state and then the ink discharge surface 42a is oriented or turned to face in the direction opposite to the z direction, thereby making it possible to route the tubes T2 and T3 and the wiring cable C2 without using a space on the one side in the z direction with respect to the head unit <NUM>.

As depicted in <FIG>, the edge member <NUM> has a first base part 45a in which the opening OP4 is formed, and a second base part 45b which extends from an end of the first base part 45a so as to be orthogonal to the first base part 45a. As depicted in <FIG>, in the first state, a length <NUM> in the z direction of the first base part 45a is same as a length l2 in the y direction of the second base part 45b. Further, as depicted in <FIG>, in the second state, the length l1 in the y direction of the first base part 45a is same as the length l2 in the z direction of the second base part 45b.

As depicted in <FIG>, the frame <NUM> includes a side surface 46a on the one side in the y direction, a side surface 46b on the one side in the z direction, and a side surface 46c on the one side in the x direction. The side surface 46a is parallel to a plane spreading in the x direction and the z direction. The side surface 46b is parallel to a plane spreading in the x direction and the y direction. The side surface 46c is parallel to a plane spreading in the y direction and the z direction. In a state that the head unit <NUM> is assembled, the side surfaces 46a, 46b and 46c of the frame <NUM> are covered, respectively, by the side surfaces 44a, 44b and 44c of the casing <NUM>. As depicted in <FIG>, an opening OP5 facing in the y direction is formed in the side surface 46a, and an opening OP6 facing in the z direction is formed in the side surface 46b. An end part in the z direction of the opening OP5 and an end part in the y direction of the opening OP <NUM> are connected or linked. Further, a cutout NT facing in the z direction is formed in the side surface 46b. The cutout NT extends in the x direction from the opening OP6. An opening OP7 and an opening OP8 facing in the x direction are formed in an end part in the z direction of the side surface 46c. The opening OP7 is connected to the opening OP8 in the y direction, and a size in the y direction and a size in the z direction of the opening OP8 are greater than a size in the y direction and a size in the z direction of the opening OP7. Further, an end part in the z direction of the opening OP7 is connected to an end part in the x direction of the cutout NT of the side surface 46b.

Here, in a case of assembling the head unit <NUM>, an operation of connecting the tube T2, the tube T3 and the wiring cable C2 extending from the tank unit <NUM>, respectively, to the damper <NUM>, the ink-jet head <NUM> and the driving substrate <NUM> of the head unit <NUM>. In this case, it is possible to perform the operation by allowing the tube T2, the tube T3 and the wiring cable C2 to pass through the opening OP8 which is greater than the openings OP5, OP6 and OP7 and which is close to the damper <NUM> and the driving substrate <NUM> in a state that the head unit <NUM> is assembled. Accordingly, it is possible to improve the efficiency of an connecting operation of connecting the tube T2, the tube T3 and the wiring cable C2 extending from the tank unit <NUM>, respectively, with respect to the damper <NUM>, the ink-jet head <NUM> and the driving substrate <NUM> of the head unit <NUM>. Further, after connecting the tube T2, the tube T3 and the wiring cable C2, respectively, with respect to the damper <NUM>, the ink-jet head <NUM> and the driving substrate <NUM>, the tube T2, the tube T3 and the wiring cable C2 are allowed to pass through, in an order of, the opening OP8, the opening OP7 and the cutout NT. Then, by pulling the tube T2, the tube T3 and the wiring cable C2 from the opening OP6 in the z direction, or from the opening OP5 in the y direction, it is possible to eliminate any looseness of the tube T2, the tube T3 and the wiring cable C2 inside the frame <NUM>. As a result, it is possible to efficiently use the internal space of the frame <NUM>.

Note that the opening OP5 is formed in a position at which the opening OP5 overlaps with the opening OP4 of the edge member <NUM> in the y direction in a case that the frame member <NUM> is attached to the casing <NUM> in the first state depicted in <FIG>. Further, the opening OP6 is formed in a position at which the opening OP6 overlaps with the opening OP4 of the edge member <NUM> in the z direction in a case that the frame member <NUM> is attached to the casing <NUM> in the second state depicted in <FIG>. Furthermore, in the first state, a center c0 in the z direction of the opening OP4 is positioned between a center c1 in the z direction of the first base part 45a and one end in the z direction of the first base part 45a (a connection part with respect to the second base part 45b), as depicted in <FIG>. Namely, the position of the opening OP4 in the first base part 45a is closer to the end part on the one side in the z direction of the first base part <NUM> than the end part on the other side in the z direction of the firs base part 45a. Similarly, in the second state, the center c0 in the y direction of the opening OP4 is positioned between the center c1 in the y direction of the first base part 45a and the one end in the y direction of the second base part 45a (the connection part with respect to the second base part 45b), as depicted in <FIG>. Namely, the position of the opening OP4 in the first base part 45a is closer to the end part on the one side in the y direction of the first base part <NUM> than the end part on the other side in the y direction of the firs base part 45a. Accordingly, in the frame <NUM>, the size in the z direction of the opening OP5 and the size in the y direction of the opening OP6 can be suppressed to be minimum. As a result, after assembling the head unit <NUM>, it is possible to make any foreign matter such as dust, etc., to be less likely to enter into the inside of the frame <NUM>.

Further, as depicted in <FIG>, a sealer <NUM> which is formed, for example, of a sponge and which is a size larger than the edge member <NUM> is interposed between the casing <NUM> and the edge member <NUM> attached to the casing <NUM>. The sealer <NUM> prevents the foreign matter such as the dust, etc., from entering into the inside of the frame <NUM> via a gap between the edge member <NUM> and the casing <NUM> and via the openings OP5, OP6 and OP7 of the frame <NUM>, after the edge member <NUM> is attached to the casing <NUM>. The sealer <NUM> has a first part 47a overlapping with the first base part 45a of the edge member <NUM>, and a second part 47b overlapping with the second base part 45b of the edge member <NUM>; an opening OP9 overlapping with the opening OP4 of the edge member <NUM> is formed in the first part 47a.

As depicted in <FIG>, an inflow port 43a to which the tube T2 is connected is formed in an end part on the other side in the z direction of the damper <NUM>. The ink flowing through the tube T2 flows into the inside of the damper <NUM> from the inflow port 43a of the damper <NUM>. On the other hand, an outflow port 43b to which the tube T4 is connected is formed in an end part on one side in the z direction of the damper <NUM>. The ink inside the damper <NUM> which flows out from the outflow port 43b is supplied to the ink-jet head <NUM> via the tube T4. Further, as depicted in <FIG>, the tube T4 has a first part T4a extending in the z direction from the outflow port 43b of the damper <NUM>, and a second part T4b which is connected to an end part in the z direction of the first part T4a and which is curbed (bent) in the y direction.

Here, in a case that the head unit <NUM> is used in the horizontal posture as depicted in <FIG> (namely, a case that the edge member <NUM> is attached to the casing <NUM> in the first state depicted in <FIG>), the outflow port 43b is positioned above the inflow port 43a, in the damper <NUM>. Accordingly, at a time of initially introducing the ink, the ink is filled in the damper <NUM> from therebelow, and the air inside the damper <NUM> can be made to escape efficiently from the outflow port 43b located at the upper position. As a result, it is possible to prevent the air from remaining inside the damper <NUM> at the time of initially introducing the ink. On the other hand, in a case that the head unit <NUM> is used in the vertical posture as depicted in <FIG> (namely, in a case that the edge member <NUM> is attached to the casing <NUM> in the second state depicted in <FIG>), the second part T4b of the tube T4 is bent or curbed upward from the first part T4a connected to the outflow port 43b of the damper <NUM>. Accordingly, at the time of initially introducing the ink, it is possible to make the air inside the damper <NUM> to escape to a location above the outflow port 43b by the first part T4a and the second part T4b of the tube T4. As a result, it is possible to prevent the air from remaining inside the damper <NUM> at the time of initially introducing the ink.

Although the foregoing explanation has been made on the premise that a conveyance surface of the conveyor CV is parallel to the xy plane, it is also conceivable that the conveyance surface of the conveyor CV is inclined with respect to the xy plane, depending on the service or usage environment of the ink-jet printer <NUM>. For example, in <FIG>, such a case is conceivable that the conveyance surface of the conveyor CV is inclined such that as the print medium M is being conveyed in the x direction, the position of the print medium M is deviated in the z direction. In a case that printing is performed with respect to one side surface (a side surface parallel to the xz plane) of the print medium M in this situation, it is necessary to incline the head unit <NUM> so that the nozzle row NR is inclined with respect to the z direction while maintaining the head unit <NUM> to be at the horizontal posture. In such a case, the head unit <NUM> of the present embodiment may further include, for example, a supporting member <NUM> as depicted in <FIG>. As depicted in <FIG>, the supporting member <NUM> is attached to the side surface 44c and to the side surface 44d which faces or is opposite to the side surface 44c (see <FIG>), at an end part in the y direction (an end part on the opposite side with respect to the ink-jet head <NUM>) of the casing <NUM>. Further, the supporting member <NUM> has a shaft 48a extending in the y direction, and supports the casing <NUM> so that the casing <NUM> is rotatable, with a central axis I of the shaft 48a as the rotational axis. As depicted in a left view of <FIG>, in a case that the supporting member <NUM> supports the casing <NUM> so that the nozzle row NR is parallel to the z direction, the central axis I of the shaft 48a passes the center in the x direction in the ink-jet head <NUM>, and passes a location between nozzles nz1 and nz2 which are, respectively, at the both ends in the nozzle row NR. Note that in the state that the nozzle row NR is parallel to the z direction, the nozzle nz21 is located at an end on the one side in the z direction, and the nozzle nz2 is located at an end on the other side in the z direction. Here, as depicted in a right view of <FIG>, the supporting member <NUM> is allowed to rotate, together with the casing <NUM>, with the central axis I of the shaft 48a as the rotational axis, so as to incline the nozzle row NR with respect to the z direction. In this case, the position of the nozzle nz1 moves to the direction opposite to the z direction (the other side in the z direction), and the position of the nozzle nz2 moves to the z direction (the one side in the z direction). Accordingly, even in a case that the casing <NUM> is supported while being inclined so that the nozzle row NR is inclined with respect to the z direction, it is possible to maintain the head difference with respect to the water surface of the ink inside the head tank <NUM> within a predetermined range. Accordingly, it is possible to prevent such a situation that the head difference is broken due to that the casing <NUM> is supported while being inclined and that the ink flows out from the nozzles.

Next, the guide bracket <NUM> will be explained. The guide bracket <NUM> is provided so as to correct or rectify a conveying direction of the print medium M conveyed by the conveyor CV and to maintain a spacing distance from the ink discharge surface 42a to the print medium M to be constant, in a case that the print medium M, which is conveyed by the conveyor CV, is conveyed so as to approach toward the ink discharge surface 42a of the ink-jet head <NUM>.

As depicted in <FIG>, the guide bracket <NUM> is provided with a first guide 49a, a second guide 49b, a third guide 49c, a bracket 49d for a photocell sensor, and a photocell sensor 49e. The first guide 49a, the second guide 49b and the third guide 49c are supported by a part, of the casing <NUM>, which is on the other side in the y direction (the right side in <FIG>). The first guide 49a is positioned on the one side in the x direction (the right side in <FIG>) with respect to the ink-jet head <NUM>, and the second guide 49b is positioned on the other side in the x direction (the left side in <FIG>) with respect to the ink-jet head <NUM>. Further, the third guide 49c is positioned, in the x direction, between the ink-jet head <NUM> and the second guide 49b.

The first guide 49a has a first guide surface 49a1 spreading in the x direction and the z direction, a first inclined surface 49a2 extending from an end part on the one side in the x direction of the first guide surface 49a1, and an attachment surface 49a3 extending toward the one side in the y direction from an end part on the other side in the x direction of the first guide surface 49a1. As depicted in a lower view of the <FIG>, the first guide surface 49a1 is positioned on the other side in the y direction with respect to the ink discharge surface 42a. Further, the first inclined surface 49a2 is connected to the end part on the one side in the x direction of the first guide surface 49a1 in a state that an end part on the other side in the x direction of the first inclined surface 49a2 is positioned on the other side in the y direction with respect to the end part on the one side in the x direction of the first inclined surface 49a2. Furthermore, the first guide surface 49a is attached to the casing <NUM> via the attachment surface 49a3. The first guide surface 49a1 is formed with two openings OP12 and OP13 penetrating the first guide surface 49a1 in the y direction. The openings OP12 and OP13 have a same shape, and are arranged side by side in the z direction. A distance d13 from an end part on the one side in the z direction of the first guide surface 49a1 to an end part on the one side in the z direction of the opening OP13 is equal to a distance d12 from an end part on the other side in the z direction of the first guide surface 49a1 to an end part on the other side in the z direction of the opening OP12. Note that it is allowable that a length in the z direction of the first guide 49a is not more than a length in the z direction of the casing <NUM>.

The second guide 49b has a second guide surface 49b <NUM> spreading in the x direction and the z direction, a second inclined surface 49b2 extending from an end part on the other side in the x direction of the second guide surface 49b1, and an attachment surface 49b3 extending toward the one side in the y direction from an end part on the one side in the x direction of the second guide surface 49b1. As depicted in the lower view of <FIG>, the second guide surface 49b1 is positioned on the other side in the y direction with respect to the ink discharge surface 42a. Further, the second inclined surface 49b2 is connected to the end part on the other side in the x direction of the second guide surface 49b1 in a state that an end part on the one side in the x direction of the second inclined surface 49b2 is positioned on the other side in the y direction with respect to the end part on the other side in the x direction of the second inclined surface 49b2. Furthermore, the second guide surface 49b is attached to the casing <NUM> via the attachment surface 49b3. The second guide surface 49b1 is formed with two openings OP10 and OP11 penetrating the second guide surface 49b1 in the y direction. The openings OP10 and OP11 have a same shape, and are arranged side by side in the z direction. A distance d11 from an end part on the one side in the z direction of the second guide surface 49b1 to an end part on the one side in the z direction of the opening OP11 is equal to a distance d10 from an end part on the other side in the z direction of the second guide surface 49b1 to an end part on the other side in the z direction of the opening OP <NUM>. Note that it is allowable that a length in the z direction of the second guide 49b is not more than the length in the z direction of the casing <NUM>.

The third guide 49c has a third guide surface 49c1 spreading in the x direction and the z direction, a third inclined surface 49c2 extending from an end part on the one side in the x direction of the third guide surface 49c1, and an attachment surface 49c3 extending toward the one side in the y direction from an end part on the other side in the x direction of the third guide surface 49c1. As depicted in the lower view of <FIG>, the third guide surface 49c1 is positioned on the other side in the y direction with respect to the ink discharge surface 42a. Further, the third inclined surface 49c2 is connected to the end part on the one side in the x direction of the third guide surface 49c1 in a state that an end part on the other side in the x direction of the third inclined surface 49c2 is positioned on the other side in the y direction with respect to the end part on the one side in the x direction of the third inclined surface 49c2. Furthermore, the third guide surface 49c is attached to the casing <NUM> via the attachment surface 49c3. Note that it is allowable that a length in the z direction of the third 49c is not more than the length in the z direction of the casing <NUM>.

As depicted in <FIG>, the bracket 49d for the photocell sensor is attached to the attachment surface 49b3 of the second guide 49b. Further, the photocell sensor 49e is supported by the bracket 49d for the photocell sensor. The photocell sensor 49e is provided with a light receiving element 49e1 configured to detect approaching, to the head unit <NUM>, of the print medium M which is being conveyed by the conveyor CV. In a state that the photocell sensor 49e is supported by the bracket 49d for the photocell sensor, the light receiving element 49e1 is positioned on the other side in the y direction in the photocell sensor 49e. Further, as seen in the y direction from the other side in the y direction, a light receiving surface of the light receiving element 49e1 is positioned inside the opening OP10 of the second guide 49b.

As explained above, in the present embodiment, the first guide 49a is provided on the one side in the x direction with respect to the ink-jet head <NUM>, and the second guide 49b and the third guide 49c are provided on the other side in the x direction with respect to the ink-jet head <NUM>. Further, in a case that the conveying direction of the print medium M is the direction opposite to the x direction of <FIG>, the first guide 49a has the first inclination surface 49a2 which is further inclined in a direction away from the ink discharge surface 42a (the direction opposite to the y direction) as advancing further toward the downstream side in the conveying direction of the print medium M (the direction opposite to the x direction). On the other hand, in a case that the conveying direction of the print medium M is the x direction of <FIG>, the second guide 49b has the second inclination surface 49b2 which is further inclined in a direction away from the ink discharge surface 42a (the direction opposite to the y direction) as advancing further toward the downstream side in the conveying direction of the print medium M (the x direction). Furthermore, each of the first guide surface 49a1 and the second guide surface 49b1 is positioned on the other side in the y direction with respect to the ink discharge surface 42a. Accordingly, in a case that the print medium M which is being conveyed by the conveyor CV is conveyed so as to approach toward the ink discharge surface 42a of the ink-jet head <NUM>, the conveying direction of the print medium M is corrected by the inclined surface on the upstream side in the conveying direction and the guide surface continued from the inclined surface, thereby making it possible to maintain the spacing distance from the ink discharge surface 42a to the print medium M to be constant. Further, also in a case that the print medium M is being conveyed in the x direction by the conveyor CV, and in a case that the print medium M is conveyed in the direction opposite to the x direction by the conveyor CV, it is possible to guide the print medium M to an appropriate position.

Further, the third guide 49c is present between the ink-jet head <NUM> and the second guide 49b. Furthermore, the third guide 49c has the third inclined surface 49c2 between the ink-jet head <NUM> and the third guide surface 49c1. Accordingly, in a case that the print medium M is being conveyed in the direction opposite to the x direction by the conveyor CV and that the conveying direction is deviated to the y direction after the print medium M has passed the ink-jet head <NUM>, it is possible to guide the print medium M to the direction opposite to the y direction by the third inclined surface 49c2. As a result, it is possible to avoid the occurrence of such a situation that the print medium M which has passed the ink-jet head <NUM> collides against the second guide 49b and that the conveyance of the print medium M is thereby stopped.

As described above, in the present embodiment, each of the first guide 49a, the second guide 49b and the third guide 49c has the length in the z direction which is not more than the length in the z direction of the casing <NUM>. Accordingly, it is possible to suppress any increase in the size in the z direction of the head unit <NUM>.

Note that in the present embodiment, the first guide 49a and the second guide 49b have a same shape. Namely, in a case that the first guide 49a is rotated by <NUM> degrees along the first guide surface 49a1, the outer shape of the first guide 49a is coincident with the outer shape of the second guide 49b. Further, as depicted in the upper view of <FIG>, in a state that the first guide 49a and the second guide 49b are attached to the casing <NUM>, the first guide 44a and the second guide 44b are in a relationship of point symmetry, with respect to a point in the center in the x direction and the point in the center in the z direction which are positioned therebetween. Accordingly, it is possible to make the parts used as the first guide 49a and the second guide 49b to be common.

In the head unit <NUM> of the present embodiment as explained above, the x direction, the y direction and the z direction are examples, respectively, of a "second direction", a "third direction" and a "first direction". The ink discharge surface 42a is an example of a "nozzle surface". The damper <NUM> is an example of a "tank". The openings OP5, OP6, OP7 and OP9 are examples, respectively, of a "first hole", a "second hole", a "third hole" and a "fourth hole". The side surfaces 46a, 46b and 46c of the frame <NUM> are examples, respectively, of a "first side surface", a "second side surface", and a "third side surface".

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, although the opening OP4 is formed in the edge member <NUM>, the present invention is not limited to or restricted by this. For example, it is allowable to form a cylindrical part which protrudes in the y direction from the first base part 45a in the first state of <FIG>. In this case, a forward end of the cylindrical part corresponds to the opening of the edge member <NUM>.

Claim 1:
A head unit (<NUM>) comprising:
a head (<NUM>) having a nozzle surface spreading in a first direction (z) and a second direction (x) crossing the first direction (z), the nozzle surface having a nozzle row (NR) formed along the first direction (z);
a tank (<NUM>) fluidly connected to the head;
a substrate (<NUM>) electrically connected to the head (<NUM>); and
a casing (<NUM>) containing the head (<NUM>), the tank (<NUM>) and the substrate (<NUM>); and
characterized by:
an edge member (<NUM>) defining an opening (OP4) through which a tube (T2, T3) and a wiring (C2) pass, the tube (T2, T3) being fluidly connectable to the tank (<NUM>), the wiring (C2) being electrically connectable to the substrate (<NUM>), the edge member (<NUM>) being configured to be detachably attachable with respect to the casing (<NUM>),
wherein the edge member (<NUM>) is configured to be attachable with respect to the casing (<NUM>) selectively in a first state and a second state, the first state being a state in which the opening (OP4) faces in a third direction (y) crossing the first direction (z) and the second direction (x), the second state being a state in which the opening (OP4) faces in the first direction (z).