Nozzle surface cleaning apparatus and droplet ejection apparatus

A nozzle surface cleaning apparatus is configured to clean a nozzle surface of a droplet ejection head in which the nozzle surface is inclined with respect to a horizontal plane. The nozzle surface cleaning apparatus includes: a cleaning liquid deposition device which deposits cleaning liquid on the nozzle surface while moving relatively to the nozzle surface in a direction perpendicular to a direction of inclination of the nozzle surface; and an excess cleaning liquid removal device which removes excess cleaning liquid adhering to a lower edge portion of the nozzle surface in terms of the direction of inclination, while moving relatively to the nozzle surface in the direction perpendicular to the direction of inclination of the nozzle surface, the excess cleaning liquid being a part of the cleaning liquid deposited by the cleaning liquid deposition device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a nozzle surface cleaning apparatus and a droplet ejection apparatus, and more particularly to a nozzle surface cleaning apparatus and a droplet ejection apparatus in which a droplet ejection head has a nozzle surface disposed obliquely with respect to the horizontal plane and the oblique nozzle surface is cleaned.

2. Description of the Related Art

When a recording operation is carried out continuously in an inkjet recording apparatus, ink adheres and accumulates in the vicinity of the nozzles and blockages occur in the nozzles. Hence, in an inkjet recording apparatus, cleaning of the nozzle surface is carried out periodically.

For example, Japanese Patent Application Publication Nos. 03-262646 and 2006-205712 disclose that the cleaning of the nozzle surface is performed by wiping the nozzle surface with a blade or an ink absorbing body.

Japanese Patent Application Publication No. 2002-019132 discloses that a cleaning liquid is applied to the nozzle surface before wiping in order to further increase the cleaning effect.

In an inkjet recording apparatus which performs color recording using a plurality of line heads while conveying a medium on a drum, if the heads of the respective colors (for example, yellow, cyan, magenta, black) are arranged about one drum, then it is necessary to obliquely dispose the respective heads about the periphery of the drum in such a manner that nozzle surfaces of the heads are oblique to the horizontal plane.

On the other hand, if cleaning is performed by applying cleaning liquid on the nozzle surfaces in the inkjet recording apparatus in which the nozzle surfaces are obliquely disposed, then a problem arises in that the applied cleaning liquid collects on the lower edges of the nozzle surfaces in the direction of inclination and irregularly drops down, causing soiling of the peripheral area.

Furthermore, in the case of a cleaning apparatus having a composition which subsequently performs wiping with an ink absorbing body, there is also a problem in that the cleaning liquid which has collected on the lower edges of the nozzle surfaces is absorbed by the ink absorbing body, the absorbing capacity of the ink absorbing body declines and wiping residue occurs.

SUMMARY OF THE INVENTION

The present invention has been contrived in view of these circumstances, an object thereof being to provide a nozzle surface cleaning apparatus and a droplet ejection apparatus whereby a nozzle surface can be cleaned reliably without soiling the periphery.

In order to attain the aforementioned object, the present invention is directed to a nozzle surface cleaning apparatus configured to clean a nozzle surface of a droplet ejection head in which the nozzle surface is inclined with respect to a horizontal plane, the apparatus comprising: a cleaning liquid deposition device which deposits cleaning liquid on the nozzle surface while moving relatively to the nozzle surface in a direction perpendicular to a direction of inclination of the nozzle surface; and an excess cleaning liquid removal device which removes excess cleaning liquid adhering to a lower edge portion of the nozzle surface in terms of the direction of inclination, while moving relatively to the nozzle surface in the direction perpendicular to the direction of inclination of the nozzle surface, the excess cleaning liquid being a part of the cleaning liquid deposited by the cleaning liquid deposition device.

According to this aspect of the present invention, the excess cleaning liquid removal device removes the excess cleaning liquid adhering to the lower edge portion of the nozzle surface in terms of the direction of inclination of the nozzle surface after the cleaning liquid is deposited. Thus, it is possible to prevent the cleaning liquid that has been deposited on the nozzle surface from dropping down from the lower edge portion of the nozzle surface in the direction of inclination and soiling the peripheral area.

Preferably, the excess cleaning liquid removal device includes a squeegee which is pressed against the lower edge portion of the nozzle surface to sweep the excess cleaning liquid.

According to this aspect of the present invention, the excess cleaning liquid adhering to the lower edge portion of the nozzle surface is removed by sweeping the excess liquid with the squeegee which is pressed against the lower edge portion of the nozzle surface. Thus, it is possible to remove the excess cleaning liquid by means of a simple composition.

Preferably, the cleaning liquid deposition device includes a cleaning liquid tray which receives the cleaning liquid falling down from the nozzle surface; and the excess cleaning liquid removal device sweeps the excess cleaning liquid into the cleaning liquid tray.

According to this aspect of the present invention, the cleaning liquid tray which receives the cleaning liquid falling down from the nozzle surface is arranged in the cleaning liquid deposition device, and the excess cleaning liquid is swept into the cleaning liquid tray. Thus, it is possible to recover the excess cleaning liquid together with the cleaning liquid which falls down naturally from the nozzle surface.

Preferably, the excess cleaning liquid removal device includes a suction device which suctions the excess cleaning liquid adhering to the lower edge portion of the nozzle surface.

According to this aspect of the present invention, the excess cleaning liquid adhering to the lower edge portion of the nozzle surface is removed by suctioning. Thus, the excess cleaning liquid can be removed and recovered simultaneously.

Preferably, the nozzle surface cleaning apparatus further comprises a wiping device which wipes the nozzle surface after the excess cleaning liquid is removed, while moving relatively to the nozzle surface in the direction perpendicular to the direction of inclination of the nozzle surface.

According to this aspect of the present invention, the nozzle surface is wiped with the wiping device after the excess cleaning liquid is removed. Since the nozzle surface is wiped after the excess cleaning liquid is removed, then it is possible to wipe the nozzle surface without giving rise to wiping residue.

Preferably, the nozzle surface cleaning apparatus further comprises a cleaning liquid type switching device which switches types of the cleaning liquid to be deposited on the nozzle surface from the cleaning liquid deposition device.

According to this aspect of the present invention, it is possible to switch the types of the cleaning liquid deposited onto the nozzle surface. By this means, for example, it is possible to clean using a cleaning liquid which corresponds to the extent of soiling of the nozzle surface, and the nozzle surface can be cleaned with good efficiency.

Preferably, the cleaning liquid deposition device includes a plurality of cleaning liquid deposition units which deposit the cleaning liquid on the nozzle surface and are aligned in the direction perpendicular to the direction of inclination of the nozzle surface; and the nozzle surface cleaning apparatus further comprises a cleaning liquid deposition control device which controls deposition of the cleaning liquid onto the nozzle surface by individually controlling the cleaning liquid deposition units.

According to this aspect of the present invention, the plurality of cleaning liquid deposition units are arranged in the direction perpendicular to the direction of inclination of the nozzle surface. By this means, for example, it is possible to increase the number of cleaning liquid deposition units used in accordance with the extent of soiling of the nozzle surface, and the nozzle surface can be cleaned with good efficiency.

Preferably, the cleaning liquid deposition units respectively deposit the cleaning liquid of different types onto the nozzle surface.

According to this aspect of the present invention, the cleaning liquid of different types are deposited onto the nozzle surface from the respective cleaning liquid deposition units. By this means, for example, it is possible to clean using a cleaning liquid which corresponds to the extent of soiling of the nozzle surface, and the nozzle surface can be cleaned with good efficiency.

Preferably, the nozzle surface cleaning apparatus further comprises a movement control device which controls and changes a speed of relative movement of the cleaning liquid deposition device and the excess cleaning liquid removal device with respect to the nozzle surface.

According to this aspect of the present invention, it is possible to change the speed of relative movement of the cleaning liquid deposition device and the excess cleaning liquid removal device with respect to the nozzle surface. By this means, for example, it is possible to change the speed of relative movement in accordance with the extent of soiling of the nozzle surface, and the nozzle surface can be cleaned with good efficiency.

In order to attain the aforementioned object, the present invention is also directed to a droplet ejection apparatus, comprising: a droplet ejection head in which a nozzle surface is inclined with respect to the horizontal plane; and the above-described nozzle surface cleaning apparatus which cleans the nozzle surface of the droplet ejection head.

According to this aspect of the present invention, the nozzle surface cleaning apparatus is incorporated in the droplet ejection apparatus in which the nozzle surface of the droplet ejection head is inclined with respect to the horizontal plane.

Preferably, the droplet ejection head includes a line head having a length corresponding to a width of a medium; and the nozzle surface is inclined in a direction perpendicular to a lengthwise direction of the line head.

According to this aspect of the present invention, the droplet ejection head includes the line head having the length corresponding to the width of the medium, and the nozzle surface is inclined in the direction perpendicular to the lengthwise of the line head.

Preferably, the droplet ejection apparatus further comprises: a conveyance drum which conveys the medium while holding the medium on a circumferential surface thereof, wherein the nozzle surface is inclined to face the circumferential surface of the conveyance drum.

According to this aspect of the present invention, the nozzle surface is inclined so as to face the circumferential surface of the conveyance drum which conveys the medium.

According to the present invention, it is possible to reduce the replacement frequency of the wiping member. Furthermore, it is possible to make the overall composition of the inkjet recording apparatus more compact in size.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Here, an example is described in which a nozzle surface cleaning apparatus according to an embodiment of the present invention is incorporated in an inkjet recording apparatus which records an image on a cut sheet of paper.

Composition of Image Recording Unit of Inkjet Recording Apparatus

FIG. 1is a side view diagram showing the general composition of an image recording unit of an inkjet recording apparatus.

As shown inFIG. 1, the image recording unit10of the inkjet recording apparatus according to the present embodiment conveys a medium (cut sheet of paper)12by means of an image recording drum14. Droplets of inks of respective colors of cyan (C), magenta (M), yellow (Y), black (K) are ejected and deposited on a surface of the medium12from inkjet heads (droplet ejection heads)16C,16M,16Y and16K, which are arranged about the periphery of the image recording drum14, whereby a color image is recorded on the surface of the medium12.

The image recording drum14is arranged rotatably, and end portions of a rotating shaft18of the image recording drum14are supported on a pair of bearings22(seeFIG. 2). The bearings22are arranged on a main frame20of the inkjet recording apparatus, and due to the end portions of the rotating shaft18being supported on this pair of bearings22, the image recording drum14is installed horizontally (the rotating shaft18is installed in parallel with the horizontal installation surface).

A motor is coupled to the rotating shaft18of the image recording drum14through a rotation transmission mechanism (not illustrated). The image recording drum14is driven by the motor to rotate.

The image recording drum14is provided with grippers24arranged on the circumferential surface thereof (in the present embodiment, at two locations on the outer circumferential surface thereof) so as to grip a leading end portion of the medium12. The leading end portion of the medium12is gripped by the grippers24and thereby held on the outer circumferential surface of the image recording drum14.

The image recording drum14is further provided with an attraction holding mechanism which is not illustrated (for example, an electrostatic attraction mechanism or a vacuum suction mechanism). The medium12which is wrapped about the outer circumferential surface of the image recording drum14and the leading end portion of which is gripped by the gripper24is held by attraction on the rear surface side thereof by the attraction holding mechanism and thereby held on the outer circumferential surface of the image recording drum14.

In the inkjet recording apparatus according to the present embodiment, the medium12is transferred to the image recording drum14through a conveyance drum26from a previous step. The conveyance drum26is disposed in parallel with the image recording drum14and transfers the medium12onto the image recording drum14in a synchronized fashion.

Furthermore, the medium12after the image recording is transferred to a subsequent step through a conveyance drum28. The conveyance drum28is disposed in parallel with the image recording drum14and receives the medium12from the image recording drum14in a synchronized fashion.

The four inkjet heads16C,16M,16Y and16K are constituted of line heads having widths corresponding to the width of the medium, and are arranged at uniform intervals apart radially on a circle concentric with the rotating shaft18of the image recording drum14.

In the present embodiment, the four inkjet heads16C,16M,16Y and16K are arranged horizontally symmetrically about the image recording drum14. In other words, the cyan inkjet head16C and the black inkjet head16K are disposed symmetrically with respect to the vertical line that passes through the center of the image recording drum14, and the magenta inkjet head16M and the yellow inkjet head16Y are also disposed horizontally symmetrically with respect to the same vertical line.

Nozzle surfaces30C,30M,30Y and30K, which are formed at lower ends of the inkjet heads16C,16M,16Y and16K disposed as described above, are positioned so as to face the outer circumferential surface of the image recording drum14, and the nozzle surfaces30C,30M,30Y and30K are disposed at a prescribed height position from the outer circumferential surface of the image recording drum14(a uniform gap is formed between the outer circumferential surface of the image recording drum14and each of the nozzle surfaces30C,30M,30Y and30K). Furthermore, inkjet nozzles are formed in the nozzle surfaces30C,30M,30Y and30K, and are arranged in rows perpendicular to the conveyance direction of the medium12.

Ink droplets are ejected perpendicularly toward the outer circumferential surface of the image recording drum14from the nozzles which are formed on the nozzle surfaces30C,30M,30Y and30K of the inkjet heads16C,16M,16Y,16K disposed as described above.

FIG. 3is a plan view perspective diagram of the nozzle surface of the inkjet head.

The nozzle surfaces have the same composition and therefore the composition of one nozzle surface30is described here.

As shown inFIG. 3, the nozzle surface30(30C,30M,30Y,30K) is formed in a rectangular shape and is constituted of a nozzle forming surface30A, in which nozzles N are formed, and nozzle protection surfaces30B, which protect the nozzle forming surface30A.

The nozzle forming surface30A is disposed in the center of the nozzle surface30and a prescribed liquid repelling treatment is applied to the nozzle forming surface30A. The inkjet recording apparatus according to the present embodiment has a composition in which the nozzles N are arranged in a two-dimensional matrix configuration in the nozzle forming surface30A. More specifically, the nozzle rows are formed by arranging the nozzles N at a uniform pitch in a direction inclined by a prescribed angle with respect to the direction of conveyance of the medium12, and furthermore a plurality of the nozzle rows are arranged at uniform pitch in the direction perpendicular to the conveyance direction of the medium12. By adopting this arrangement for the nozzles, it is possible to reduce the effective pitch between the nozzles N as projected to the lengthwise direction of the head (namely, a direction perpendicular to the conveyance direction of the medium12), and therefore a high-density configuration of the nozzles N can be achieved.

The nozzle protection surfaces30B are arranged on either side of the nozzle forming surface30A. The nozzle protection surfaces30B are formed to project by a prescribed amount from the nozzle forming surface30A.

The nozzles N formed in the nozzle surface30are connected respectively to pressure chambers P, and droplets of ink are ejected from the nozzles N by expanding and contracting the volume of the pressure chambers P by means of actuators, such as piezoelectric elements.

The image recording unit10has the composition described above. In the image recording unit10, the medium12is received onto the image recording drum14from the previous step through the conveyance drum26, and is conveyed in rotation while being held by attraction on the circumferential surface of the image recording drum14. The medium12passes below the inkjet heads16C,16M,16Y and16K during this conveyance and ink droplets are ejected and deposited from the inkjet heads16C,16M,16Y and16K onto the recording surface of the medium12as the medium12passes, thereby forming a color image on the recording surface of the medium12. After having completed the image recording, the medium12is transferred from the image recording drum14to the conveyance drum28and is conveyed to the subsequent step.

In the image recording unit10having the composition described above, the inkjet heads16C,16M,16Y and16K are installed on a head supporting frame40and are arranged around the image recording drum14as shown inFIG. 2.

The head supporting frame40is constituted of a pair of side plates42L and42R, which are arranged perpendicularly to the rotating shaft18of the image recording drum14, and a linking frame44, which links the pair of side plate42L and42R together at the upper end portions thereof.

Each of the side plates42L and42R is formed in a plate shape, and the side plates42L and42R are disposed so as to face each other across the image recording drum14. Installation sections46C,46M,46Y and46K for installing the respective inkjet heads16C,16M,16Y and16K are provided on the inner side faces of the pair of side plates42L and42R (only the installation sections46Y and46K are depicted inFIG. 2).

The installation sections46C,46M,46Y and46K are disposed at a uniform spacing apart radially on a circle concentric with the rotating shaft18of the image formation drum14. The inkjet heads16C,16M,16Y and16K are installed on the head supporting frame40by fixing attachment sections48C,48M,48Y and48K, which are formed on the respective ends of the heads (only the attachment sections48Y and48K are depicted inFIG. 2) onto the installation sections46C,46M,46Y and46K. By installing the inkjet heads16C,16M,16Y and16K on the head supporting frame40, the inkjet heads16C,16M,16Y and16K are disposed at uniform intervals apart radially on a circle concentric with the rotating shaft18of the image formation drum14.

The head supporting frame40for installing the inkjet heads16C,16M,16Y and16K is arranged slidably in a direction parallel to the rotating shaft18of the image formation drum14by being guided by guide rails (not illustrated). The head supporting frame40is arranged movably between an “image recording position” indicated by the solid lines inFIG. 2and a “maintenance position” indicated by the dotted lines inFIG. 2, by being driven by a linear drive mechanism (not illustrated) such as, for example, a screw feed mechanism.

When the head supporting frame40is disposed in the image recording position, the inkjet heads16C,16M,16Y and16K are disposed about the periphery of the image recording drum14and assume a state capable of image recording.

On the other hand, when the head supporting frame40is disposed in the maintenance position, the inkjet heads16C,16M,16Y and16K are retracted from the image recording drum14. A moisturizing unit50for moisturizing the inkjet heads16C,16M,16Y and16K is provided in this maintenance position. When the inkjet heads16C,16M,16Y and16K are not used for a long time, the head supporting frame40is placed in the maintenance position and the inkjet heads16C,16M,16Y and16K are moisturized by the moisturizing unit50. Thereby, ejection failure due to drying is prevented.

The movement of the head supporting frame40is controlled by a controller (not shown). This controller is a control unit which performs overall control of the operation of the whole inkjet recording apparatus, and controls the movement of the head supporting frame40by controlling the driving of the linear drive mechanism.

A nozzle surface cleaning apparatus60for cleaning the nozzle surfaces30C,30M,30Y and30K of the inkjet heads16C,16M,16Y and16K is arranged between the image recording position and the maintenance position. When the inkjet heads16C,16M,16Y and16K are moved from the image recording position to the maintenance position, cleaning liquid is deposited onto the nozzle surfaces30C,30M,30Y and30K from the nozzle surface cleaning apparatus60, and the nozzle surfaces30C,30M,30Y and30K are wiped with wiping webs and cleaned.

Below, the composition of the nozzle surface cleaning apparatus60is described.

Composition of Nozzle Surface Cleaning Apparatus

First Embodiment

As shown inFIG. 2, the nozzle surface cleaning apparatus60includes: a cleaning liquid deposition device62, which deposits the cleaning liquid onto the nozzle surfaces30C,30M,30Y and30K of the inkjet heads16C,16M,16Y and16K; and a wiping device64, which wipes the nozzle surface30C,30M,30Y and30K of the inkjet heads16C,16M,16Y and16K on which the cleaning liquid has been deposited.

The cleaning liquid deposition device62and the wiping device64are arranged on a movement path of the head supporting frame40, and the cleaning liquid deposition device62is arranged to the image recording drum14side of the wiping device64. In other words, the cleaning liquid deposition device62is arranged on the upstream side of the wiping device64in terms of the direction of movement of the head supporting frame40from the image recording position toward the maintenance position.

<Composition of Cleaning Liquid Deposition Device>

FIG. 4is a side view diagram showing the cleaning liquid deposition device62viewed from the maintenance position side.

The cleaning liquid deposition device62is constituted of cleaning liquid deposition units200C,200M,200Y and200K, which are arranged correspondingly to the inkjet heads16C,16M,16Y and16K, and a base202, on which the cleaning liquid deposition unit200C,200M,200Y and200K are mounted.

The base202is horizontally arranged so as to be raisable and lowerable by an elevator device (not shown). Cleaning liquid deposition unit attachment sections202C,202M,202Y and202K are formed in the upper surface portion of the base202. The cleaning liquid deposition units200C,200M,200Y and200K are fixed to the cleaning liquid deposition unit attachment sections202C,202M,202Y and202K formed on the base202, by bolts, or the like, and are thereby installed in prescribed positions. By installing the cleaning liquid deposition units200C,200M,200Y and200K on the base202, the cleaning liquid deposition units200C,200M,200Y and200K are arranged over the movement path of the corresponding inkjet heads16C,16M,16Y and16K (namely, over the movement path from the image recording position to the maintenance position).

<<Composition of Cleaning Liquid Deposition Unit>>

Next, the composition of the cleaning liquid deposition units200C,200M,200Y and200K is described.

The cleaning liquid deposition units200C,200M,200Y and200K each have the same basic composition and therefore the composition of a cleaning liquid deposition unit200is described here.

FIG. 5is a front view diagram of the cleaning liquid deposition unit200, andFIGS. 6 and 7are side view diagrams of the cleaning liquid deposition unit200, observed from the maintenance position side and the image recording position side, respectively.

As shown inFIGS. 5 to 7, the cleaning liquid deposition unit200includes: a cleaning liquid deposition head210, which deposits the cleaning liquid onto the nozzle surface30; a squeegee212, which sweeps, from the nozzle surface30, excess cleaning liquid which has collected on the lower edge of the nozzle surface30in the direction of inclination; and a cleaning liquid recovery tray214, which recovers the cleaning liquid falling down from the nozzle surface30.

The cleaning liquid recovery tray214is formed in the shape of a rectangular box of which the upper portion is open. The cleaning liquid deposition head210and the squeegee212are arranged inside the cleaning liquid recovery tray214.

The cleaning liquid deposition head210is formed in a rectangular block shape with an inclined upper surface, and has a cleaning liquid holding surface216, which is parallel to the nozzle surface30, on the upper portion thereof. The cleaning liquid holding surface216is formed at the same angle of inclination of the nozzle surface30of the head that is to be cleaned, and is formed to a slightly greater width than the width of the nozzle surface30(the width in the medium conveyance direction).

A cleaning liquid emission port218is formed in the vicinity of the upper part of the cleaning liquid holding surface216, and the cleaning liquid flows out from the cleaning liquid emission port218. The cleaning liquid which has flowed out from the cleaning liquid emission port218flows down the inclined cleaning liquid holding surface216and is recovered in the cleaning liquid recovery tray214. By setting the gap between the cleaning liquid holding surface216and the nozzle surface30to a uniform value, when the nozzle surface30passes over the cleaning liquid holding surface216, the cleaning liquid which has flowed down over the cleaning liquid holding surface216makes contact with the nozzle surface30and the cleaning liquid is thereby deposited on the nozzle surface30.

A cleaning liquid supply flow channel220connected to the cleaning liquid emission port218is formed inside the cleaning liquid deposition head210. The cleaning liquid supply flow channel220is connected to a connection flow channel221formed in the cleaning liquid recovery tray214. A cleaning liquid supply port222connected to the connection flow channel221is formed in the cleaning liquid recovery tray214, and the cleaning liquid flows out from the cleaning liquid emission port218due to the cleaning liquid being supplied to the cleaning liquid supply port222.

The cleaning liquid supply port222is connected to a cleaning liquid supply tank226through a cleaning liquid supply channel224. A cleaning liquid supply pump228is arranged at an intermediate position of the cleaning liquid supply channel224, and by driving the cleaning liquid supply pump228, the cleaning liquid is supplied from the cleaning liquid supply tank226to the cleaning liquid supply port222.

The squeegee212is formed in a plate shape of a material having elastic properties, such as silicone rubber, EPDM (ethylene propylene dyne monomer rubber), NBR (nitriles butadiene rubber), urethane, or the like. A squeegee installation section230for installing the squeegee212is arranged inside the cleaning liquid recovery tray214. The squeegee installation section230is arranged on the maintenance position side with respect to the cleaning liquid deposition head210. The squeegee212is installed vertically on the squeegee installation section230. The squeegee212installed on the squeegee installation section230is arranged perpendicularly with respect to the lengthwise direction of the nozzle surface30.

The tip portion of the squeegee212is formed at an inclination correspondingly to the nozzle surface30of the head that is to be cleaned (namely, is formed at an angle of inclination which is the same as the angle of inclination of the nozzle surface to be cleaned).

When the nozzle surface30passes the squeegee212, the tip portion of the squeegee212abuts and presses against the lower edge portion of the nozzle surface30in the direction of inclination. Thereby, it is possible to sweep excess cleaning liquid which has collected on the lower edge portion of the nozzle surface30in the direction of inclination, by means of the squeegee212.

The excess cleaning liquid swept with the squeegee212drops down under its own weight and is recovered in the cleaning liquid recovery tray214.

The cleaning liquid recovery tray214is formed in the shape of the rectangular box, the upper portion of which is open, as described above. The bottom face of the interior of the cleaning liquid recovery tray214is formed at an inclination to the center. A cleaning liquid recovery hole232is formed in the central portion of the bottom face of the cleaning liquid recovery tray214. A cleaning liquid discharge port236connected to the cleaning liquid recovery hole232through a cleaning liquid recovery flow channel234is formed in the side face portion of the cleaning liquid recovery tray214.

The cleaning liquid discharge port236is connected to a cleaning liquid recovery tank240through a cleaning liquid recovery channel238. The cleaning liquid recovered by the cleaning liquid recovery tray214is recovered into the cleaning liquid recovery tank240.

Each of the cleaning liquid deposition units200(200C,200M,200Y,200K) is composed as described above. The cleaning liquid deposition device62is composed by installing the cleaning liquid deposition units200C,200M,200Y and200K on the cleaning liquid deposition unit installation sections202C,202M,202Y and202K formed in the base202.

The operation of the cleaning liquid deposition device62is controlled by a controller, which is not illustrated. The controller controls the cleaning liquid deposition operation by the cleaning liquid deposition device62by controlling the driving of the elevator device, the cleaning liquid supply pump228, and the like.

<<Action of Cleaning Liquid Deposition Device>>

Next, a cleaning liquid deposition operation by the cleaning liquid deposition device62according to the present embodiment having the composition described above is explained.

The cleaning liquid deposition device62deposits the cleaning liquid onto the nozzle surfaces30(30C,30M,30Y,30K) of the inkjet heads16(16C,16M,16Y,16K) while the inkjet heads16(16C,16M,16Y,16K) move from the image recording position to the maintenance position. More specifically, the cleaning liquid is deposited as follows.

The whole of the cleaning liquid deposition device62is arranged raisable and lowerable. When not performing cleaning, the cleaning liquid deposition device62is disposed in a prescribed standby position. During cleaning, the cleaning liquid deposition device62is raised by a prescribed amount from the standby position to a prescribed operating position.

When the cleaning liquid deposition device62is moved to the operating position, the cleaning liquid deposition units200C,200M,200Y and200K are set in prescribed cleaning liquid deposition positions. Thereby, it is possible to deposit the cleaning liquid onto the nozzle surfaces30C,30M,30Y and30K of the inkjet heads16C,16M,16Y and16K, by means of the cleaning liquid deposition heads210arranged in the cleaning liquid deposition units200C,200M,200Y and200K, and it is also possible to sweep excess cleaning liquid which collects on the lower edge portions of the nozzle surfaces30C,30M,30Y and30K of the inkjet heads16C,16M,16Y and16K in the direction of inclination, by means of the squeegees212arranged on the cleaning liquid deposition units200C,200M,200Y and200K. In other words, when the cleaning liquid deposition units200C,200M,200Y and200K are set in the cleaning liquid deposition position, they are set in the positions where the cleaning liquid which has flowed over the cleaning liquid holding surfaces216of the cleaning liquid deposition heads210makes contact with the nozzle surfaces30C,30M,30Y and30K (i.e., the positions where the gaps between the cleaning liquid holding surfaces216and the nozzle surfaces30C,30M,30Y and30K are in a prescribed range). Furthermore, the cleaning liquid deposition units200C,200M,200Y and200K are set in the positions where the tip portions of the squeegees212abut and press against the lower edge portions of the nozzle surfaces30C,30M,30Y and30K in the direction of inclination.

When the cleaning liquid deposition units200C,200M,200Y and200K are set in the prescribed cleaning liquid deposition position, the controller drives the linear drive mechanism and causes the head supporting frame40to move at a prescribed speed of movement from the image recording position to the maintenance position.

On the other hand, the controller also drives the cleaning liquid supply pump228in accordance with the timing at which the inkjet heads16C,16M,16Y and16K arrive at the cleaning liquid deposition heads210of the cleaning liquid deposition units200C,200M,200Y and200K. Thereby, the cleaning liquid flows out at a prescribed flow rate from the cleaning liquid emission ports218of the cleaning liquid deposition heads210in the respective cleaning liquid deposition units200C,200M,200Y and200K. The cleaning liquid which has flowed out from the cleaning liquid emission ports218flows down over the cleaning liquid holding surfaces216.

When the inkjet heads16C,16M,16Y and16K moving toward the maintenance position pass the cleaning liquid deposition heads210, the cleaning liquid which has flowed over the cleaning liquid holding surfaces216of the cleaning liquid deposition heads210contacts the nozzle surfaces30C,30M,30Y and30K, and the cleaning liquid is thereby deposited on the nozzle surfaces30C,30M,30Y and30K.

In the inkjet recording apparatus according to the present embodiment, as shown inFIG. 2, the inkjet heads16C,16M,16Y and16K are arranged about the periphery of the image recording drum14, and are obliquely disposed (i.e., the nozzle surfaces30C,30M,30Y and30K are inclined with respect to the horizontal plane). As a result of this, the cleaning liquid deposited on the nozzle surfaces30C,30M,30Y and30K is liable to collect in the lower edge portions of the nozzle surfaces30C,30M,30Y and30K in the direction of inclination.

However, in the cleaning liquid deposition device62according to the present embodiment, by arranging the squeegees212in the cleaning liquid deposition units200C,200M,200Y and200K, it is possible to remove excess liquid which collects in the lower edge portions of the nozzle surfaces30C,30M,30Y and30K in the direction of inclination.

More specifically, the nozzle surfaces30C,30M,30Y and30K on which the cleaning liquid has been deposited by the cleaning liquid deposition heads210pass the installation positions of the squeegees212after the cleaning liquid has been deposited thereon by passing the cleaning liquid deposition heads210, and in so doing, the squeegees212abut and press against the lower edge portions of the nozzle surfaces30C,30M,30Y and30K in the direction of inclination. Thereby, the excess cleaning liquid which has collected on the lower edge portions in the direction of inclination is swept with the squeegees212, and is removed from the nozzle surfaces30C,30M,30Y and30K.

Thus, by means of the cleaning liquid deposition device62in the present embodiment, it is possible to deposit the cleaning liquid onto the whole of the nozzle surfaces, without excess cleaning liquid collecting in the lower edge portions in the direction of inclination.

FIG. 8is a side view diagram showing the wiping device64viewed from the maintenance position side.

As shown inFIG. 8, the wiping device64includes wiping units100C,100M,100Y and100K, which are arranged correspondingly to the inkjet heads16C,16M,16Y and16K, and a rack102, in which the wiping units100C,100M,100Y and100K are set.

The rack102is horizontally arranged so as to be raisable and lowerable by an elevator device (not shown). The rack102is formed in a box shape having an open upper end portion, and installation sections104C,104M,104Y and104K for installing the wiping units100C,100M,100Y and100K are arranged inside the rack102. The wiping units100C,100M,100Y and100K are set in the respective installation sections104C,104M,104Y and104K by being inserted vertically downward through the upper end openings of the installation sections104C,104M,104Y and104K.

Next, the composition of the wiping units100C,100M,100Y and100K is described.

The wiping units100C,100M,100Y and100K all have the same basic composition and therefore the composition is described here with respect to one wiping unit100.

FIG. 9is a plan diagram of the wiping unit100,FIG. 10is a partial cross-sectional side view of the wiping unit100,FIG. 11is a partial cross-sectional front view of the wiping unit100, andFIG. 12is a rear view of the wiping unit100.

As shown inFIGS. 9 to 12, the wiping unit100has a wiping web110formed in a band shape, which is wrapped about a pressing roller118obliquely disposed, and the wiping unit100wipes and cleans the nozzle surface of the inkjet head by pressing the wiping web110wrapped about the pressing roller118, against the nozzle surface of the inkjet head.

The wiping unit100includes: a case112; a supply spindle114, which supplies the wiping web110; a take-up spindle116, which takes up the wiping web110; a front-stage guide120, which guides the wiping web110supplied from the supply spindle114so as to be wrapped about the pressing roller118; a rear-stage guide122, which guides the wiping web110having been wrapped about the pressing roller118so as to be taken up onto the take-up spindle116; and a drive roller124, which drives the wiping web110.

The case112is constituted of a case main body126and a lid128. The case main body126is formed in a box shape, which is long in the vertical direction, and the upper end portion and the front face portion thereof are open. The lid128is attached to the front face portion of the case main body126with a hinge130. The front face portion of the case main body126is opened and closed by means of the lid128.

The lid128is provided with an elastically deformable locking hook132, and the lid128is fixed to the case main body126by means of the locking hook132, which elastically deforms and engages with a hook receiving section134formed on the case main body126.

The supply spindle114is disposed so that the axis thereof is horizontal, and the base end portion thereof is rotatably supported on a bearing section136, which is arranged in the case main body126. A supply reel138having a flange138aon the base end portion thereof is installed on the supply spindle114. The supply reel138is fixed onto the supply spindle114, and rotates in unison with the supply spindle114.

As described below, the wiping web110which is wrapped in the form of a roll about a winding core110A is installed on the supply spindle114by fitting the winding core110A onto the supply reel138.

The take-up spindle116is disposed so that the axis thereof is horizontal, at a position below the supply spindle114. More specifically, the take-up spindle116is arranged below and parallel with the supply spindle114. The vicinity of the base end portion of the take-up spindle116is rotatably supported on a bearing section140, which is arranged in the case main body126.

A take-up reel142having a flange142aon the base end portion thereof is installed on the take-up spindle116. A sliding member144is installed on the inner circumference of the axle portion of the take-up reel142, and is composed so as to slide with respect to the take-up spindle116when a prescribed load or greater is applied in the direction of rotation.

As described below, a winding core110B which is attached to the leading end of the wiping web110is installed on the take-up spindle116by fitting onto the take-up reel142.

Furthermore, the take-up spindle116is arranged in such a manner that the base end portion thereof projects to the outer side of the case main body126, and a take-up gear158is fixed to this projecting base end portion of the take-up spindle116. The take-up spindle116is rotated by driving and rotating the take-up gear158. The related drive system is described hereinafter.

The pressing roller118is disposed above the supply spindle114(in the present embodiment, the pressing roller118, the supply spindle114and the take-up spindle116are disposed on the same straight line), and is arranged at a prescribed inclination with respect to the horizontal plane. In other words, the pressing roller118is disposed in accordance with the inclination of the nozzle surface of the inkjet head that is to be cleaned (i.e., the axis of the pressing roller118is parallel with the nozzle surface) in order to press the wiping web110against the nozzle surface of the inkjet head.

The pressing roller118is provided with axle portions118L and118R, which project on either end portion thereof, and the axle portions118L and118R are supported by a pair of axle supporting sections146L and146R in a rotatable and swingable fashion.

FIG. 13is a partial cross-sectional front view diagram showing the composition of the axle supporting sections which support the axle sections118L and118R of the pressing roller118, andFIG. 14is a cross-sectional diagram along14-14inFIG. 13.

As shown inFIG. 13, the axle supporting sections146L and the146R are arranged on an elevator stage170, which is horizontally disposed. The axle supporting sections146L and146R are constituted of pillar sections150L and150R, which are vertically erected on the elevator stage170, and supporting sections152L and152R, which are arranged in a bent fashion at the top ends of the pillar sections150L and150R.

The supporting sections152L and152R are arranged perpendicularly to the axle of the pressing roller118, and recess sections154L and154R are formed in the inner sides thereof. Each of the recess sections154L and154R is formed in a rectangular shape, which has a breadth substantially equal to (slightly larger than) the diameter of each of the axle sections118L and118R of the pressing roller118, and the lengthwise direction thereof is perpendicular to the nozzle surface of the inkjet head that is to be cleaned (seeFIG. 14). The axle sections118L and118R on either end of the pressing roller118are fitted freely into the recess sections154L and154R of the supporting sections152L and152R. Thus, the pressing roller118is supported swingably within the plane perpendicular to the nozzle surface of the inkjet head that is to be cleaned.

Springs156L and156R are accommodated inside the recess sections154L and154R, and the axle sections118L and118R of the pressing roller118which are fitted freely inside the recess sections154L and154R are pressed upward by the springs156L and156R. By this means, it is possible to cause the circumferential surface of the pressing roller118to make close contact with the nozzle surface, by following the nozzle surface of the line head that is to be cleaned.

The front-stage guide120is constituted of a first front-stage guide160and a second front-stage guide162, and the wiping web110supplied from the supply spindle114is guided so as to wrap about the pressing roller118, which is obliquely disposed.

On the other hand, the rear-stage guide122is constituted of a first rear-stage guide164and a second rear-stage guide166, and the wiping web110which has been wrapped about the pressing roller118obliquely disposed is guided so as to be taken up onto the horizontally disposed take-up spindle116.

The front-stage guide120and the rear-stage guide122are disposed symmetrically about the pressing roller118. More specifically, the first front-stage guide160and the first rear-stage guide164are disposed symmetrically about the pressing roller118, and furthermore the second front-stage guide162and the second rear-stage guide166are disposed symmetrically about the pressing roller118.

The first front-stage guide160is formed in a plate shape having a prescribed width and is vertically erected on the elevator stage170. The upper edge portion160A of the first front-stage guide160is formed as a supporting section for the wiping web110, and the surface thereof is formed in a circular arc shape. Furthermore, the upper edge portion160A is formed at a prescribed angular inclination with respect to the horizontal plane, whereby the travel direction of the wiping web110is changed.

The first rear-stage guide164has the same composition as the first front-stage guide160. More specifically, the first rear-stage guide164is formed in a plate shape having a prescribed width and is vertically erected on the elevator stage170. The upper edge portion164A is formed as a supporting section for the wiping web110and is formed in a circular arc shape. Furthermore, the upper edge portion164A is formed at a prescribed angular inclination with respect to the horizontal plane.

The first front-stage guide160and the first rear-stage guide164are disposed symmetrically about the pressing roller118. The travel direction of the wiping web110which has been supplied from the supply spindle114is changed to a direction substantially perpendicular to the axis of the pressing roller118from the direction perpendicular to the axis of the supply spindle114, by wrapping the wiping web110about the first front-stage guide160. The travel direction of the wiping web110having been wrapped about the second rear-stage guide166described below is changed to a direction perpendicular to the axis of the take-up spindle116by wrapping the wiping web110about the first rear-stage guide164.

The second front-stage guide162is formed as a guide roller having flanges162L and162R on the respective end portions thereof. The second front-stage guide162is disposed between the first front-stage guide160and the pressing roller118, and guides the wiping web110which has wrapped about the first front-stage guide160so as to be wrapped about the pressing roller118. More specifically, the travel direction of the wiping web110which has been changed to the direction substantially perpendicular to the axis of the pressing roller118by the first front-stage guide160is slightly adjusted so that the wiping web110travels in the direction just perpendicular to the axis of the pressing roller118. Furthermore, skewed travel of the wiping web110is prevented by the flange sections162L and162R on the respective ends of the first front-stage guide160.

The second front-stage guide162is supported at only one end thereof on a bracket168A, and the second front-stage guide162is disposed at a prescribed angular inclination. As shown inFIGS. 12 and 15, the bracket168A is formed in a plate shape with a bent top end, and the base end portion of the bracket168A is fixed to the upper end portion of the rear face of the case main body126. The bracket168A is arranged so as to project perpendicularly upward from the upper end portion of the case main body126. The second front-stage guide162is rotatably supported at only one end thereof on the bent portion of the top end of the bracket168A.

The second rear-stage guide166has the same composition as the second front-stage guide162. More specifically, the second rear-stage guide166is formed as a guide roller having flanges166L and166R on either end portion thereof, and the second rear-stage guide166is supported at only one end thereof on a bracket168B. The second rear-stage guide166is arranged at a prescribed angular inclination. The bracket168B is formed in a plate shape with a bent top end, and the base end portion of the bracket168B is fixed to the upper end portion of the rear face of the case main body126. The second rear-stage guide166is rotatably supported at only one end thereof on the bent portion of the top end of the bracket168B.

The second rear-stage guide166is disposed between the pressing roller118and the first rear-stage guide164, and guides the wiping web110which has been wrapped about the pressing roller118so as to be wrapped about the first rear-stage guide164.

The second front-stage guide162and the second rear-stage guide166are disposed symmetrically about the pressing roller118. The wiping web110of which the travel direction has been changed to the direction substantially perpendicular to the axis of the pressing roller118by the first front-stage guide160is wrapped about the second front-stage guide162, whereby the travel direction of the wiping web110is slightly adjusted so that the wiping web110travels in the direction just perpendicular to the axis of the pressing roller118. Furthermore, the travel direction of the wiping web110having been wrapped about the pressing roller118is slightly adjusted by the second rear-stage guide166so that the wiping web110can be wrapped about the first rear-stage guide164. By wrapping the wiping web110about the first rear-stage guide164, the travel direction of the wiping web110is changed to the direction perpendicular to the axis of the take-up spindle116.

Thus, the front-stage guide120and the rear-stage guide122guide the wiping web110by gradually changing the travel direction of the wiping web110, so that the wiping web110can be wrapped about the pressing roller118readily.

Consequently, the angle of inclination of the second front-stage guide162is closer to the angle of inclination of the pressing roller118than the angle of inclination of the first front-stage guide160, and similarly, the angle of inclination of the second rear-stage guide166is closer to the angle of inclination of the pressing roller118than the angle of inclination of the first rear-stage guide164.

As described above, the first front-stage guide160, the pressing roller118and the first rear-stage guide164(the first structural body constituted of the first front-stage guide160, the pressing roller118and the first rear-stage guide164) are arranged on the elevator stage170. The elevator stage170can be raised and lowered in the direction vertical to the horizontal plane.

As shown inFIG. 10, a guide shaft172is connected integrally with the elevator stage170. The guide shaft172vertically extends downward from the lower face of the elevator stage170and is fitted into a guide bush174disposed inside the case main body126. The guide bush174is fixed to the inner wall face of the case main body126through a supporting member176, and guides the guide shaft172vertically.

In this way, the elevator stage170on which the first front-stage guide160, the pressing roller118and the first rear-stage guide164are disposed is arranged raisably and lowerably in the direction vertical to the horizontal plane. Therefore, as shown inFIGS. 16A and 16B, by raising and lowering the elevator stage170, it is possible to cause the first front-stage guide160, the pressing roller118and the first rear-stage guide164to advance and retreat with respect to the second front-stage guide162and the second rear-stage guide166(the second structural body constituted of the second front-stage guide162and the second rear-stage guide166), which are fixedly arranged. By this means, it is possible to simply replace the wiping web110.

More specifically, by lowering the elevator stage170, as shown inFIG. 16B, the first front-side guide160, the pressing roller118and the first rear-stage guide164can be retracted downward with respect to the second front-stage guide162and the second rear-stage guide166, and therefore a large space between same can be ensured. Thereby, it is possible to simply carry out the task of wrapping the wiping web110about the respective sections. Furthermore, the wiping web110can be simply wrapped about the respective sections by wrapping the wiping web110about the first front-stage guide160, the pressing roller118and the first rear-stage guide164, with the first front-stage guide160, the pressing roller118and the first rear-stage guide164in the downwardly retracted state, and then raising the elevator stage170. In other words, if the wiping web110is wrapped about the first front-stage guide160, the pressing roller118and the first rear-stage guide164, whereupon the elevator stage170is raised, as shown inFIG. 16A, then the wiping web110is automatically wrapped about the second front-stage guide162and the second rear-stage guide166.

In this way, by making the first front-stage guide160, the pressing roller118and the first rear-stage guide164capable of advancing and retracting with respect to the second front-stage guide162and the second rear-stage guide166, it is possible to simply carry out the task of replacing the wiping web110.

The first front-stage guide160, the pressing roller118and the first rear-stage guide164need to be positioned in the prescribed use position (the position inFIG. 16A) when being used, and the first front-stage guide160, the pressing roller118and the first rear-stage guide164are moved to the use position in coordination with the installation of the wiping unit100on the rack102.

This coordinated mechanism will now be described. As shown inFIGS. 10 and 12, an elevator lever (engagement section)178is arranged on the elevator stage170, on which the first front-stage guide160, the pressing roller118and the first rear-stage guide164are arranged. The elevator lever178is arranged so as to project from the rear face of the case main body126through a cutaway portion180formed on the rear face of the case main body126. The elevator stage170is raised and lowered by sliding the elevator lever178.

On the other hand, as shown inFIGS. 17A and 17B, a pin (engaged section)182is projectingly arranged on the inner side of the installation section104(104C,104M,104Y and104K) of the rack102in which the wiping unit100is set. The pin182is arranged so as to engage with the elevator lever178arranged on the wiping unit100when the wiping unit100is installed on the installation section104.

According to the composition described above, as shown inFIGS. 17A and 17B, when the wiping unit100is inserted into the installation section104of the rack102, the elevator lever178engages with the pin182and is forcibly raised up to a prescribed position. Thereby, the first front-stage guide160, the pressing roller118and the first rear-stage guide164are registered in the prescribed use position.

In this way, the first front-stage guide160, the pressing roller118and the first rear-stage guide164are moved to the use position in coordination with the installation of the wiping unit100on the rack102.

The drive roller124is disposed in the vicinity of the base face of the case main body126, in a position below the first rear-stage guide164. The drive roller124drives and guides the wiping web110of which the travel direction has been changed to the direction perpendicular to the take-up spindle116by the first rear-stage guide164, so that the wiping web110is taken up onto the take-up spindle116.

The drive roller124is arranged in parallel with the take-up spindle116(namely in parallel with the horizontal plane), and the vicinity of the base end portion thereof is rotatably supported on a bearing section184, which is arranged on the case main body126.

Furthermore, the drive roller124is arranged in such a manner that the base end portion of the rotating shaft thereof projects to the outer side of the case main body126, and a roller drive gear186is fixed to this projecting base end portion of the rotating shaft. The drive roller124is rotated by driving the roller drive gear186to rotate.

Here, the drive system of the wiping unit100including the drive roller124is described.

In the wiping unit100according to the present embodiment, by driving the take-up spindle116to rotate while also driving the drive roller124to rotate, the wiping web110is caused to travel from the supply spindle114toward the take-up spindle116.

As described above, the take-up gear158is fixed to the base end portion of the take-up spindle116, and the roller drive gear186is fixed to the base end portion of the rotating shaft of the drive roller124. As shown inFIG. 12, the take-up gear158and the roller drive hear186mesh with an idle gear188.

The rotating shaft of the idle gear188is horizontally arranged and is rotatably supported on a bearing section190arranged on the case main body126. The take-up gear158and the roller drive gear186are both caused to rotate in the same direction by driving the idle gear188. The idle gear188meshes with a drive gear192arranged inside the installation section104when the wiping unit100is installed in the installation section104of the rack102. More specifically, as shown inFIGS. 17A and 17B, a motor194forming a source of drive power is arranged in the base portion of the installation section104, and the idle gear188meshes with the drive gear192, which is fixed to the output shaft of the motor194, when the wiping unit100is installed in the installation section104of the rack102.

In this way, the idle gear188meshes with the drive gear192arranged inside the installation section104when the wiping unit100is installed in the installation section104of the rack102. When the drive gear192is caused to rotate by the motor194, the idle gear188rotates and this rotation of the idle gear188is transmitted to the roller drive gear186of the take-up gear158, thereby rotating the take-up spindle116and the drive roller124. Due to the rotation of the take-up spindle116and the driver roller124, the wiping web110is supplied from the supply spindle114, and taken up onto the take-up spindle116after passing along a prescribed path of travel.

As described above, the sliding member144is installed on the inner circumference of the axle portion of the take-up reel142, which is installed on the take-up spindle116, and the take-up reel142is composed so as to slide with respect to the take-up spindle116when the prescribed load or greater is applied in the direction of rotation. Consequently, the sliding member144slides if a velocity difference occurs between the take-up spindle116and the drive roller124, and therefore allows the wiping web110to be conveyed at a uniform velocity at all times.

The wiping units100(100C,100M,100Y,100K) are composed as described above. The wiping device64is composed by installing the wiping units100C,100M,100Y and100K on the rack102.

The operation of the wiping device64is controlled by a controller, which is not illustrated. The controller controls the wiping operation by the wiping device64by controlling the driving of the elevator device, motor194, and the like.

Next, the action of the wiping device64according to the present embodiment having the aforementioned composition is described.

The method of installation the wiping web110on the wiping unit100is described.

The wiping web110is formed in a band shape having the prescribed width, and the winding cores110A and110B are attached respectively to either end thereof. The wiping web110is supplied in the form of a roll wound up onto the winding core110A, one of the winding cores.

Firstly, the wiping unit100is taken out from the rack102and the lid128of the case112is opened. Upon opening the lid128, the supply reel138which is installed on the supply spindle114and the take-up reel142which is installed on the take-up spindle116are exposed, and then the winding cores110A and110B of the wiping web110are installed respectively on the supply reel138and the take-up reel142. The winding cores110A and110B of the wiping web110are installed on the supply reel138and the take-up reel142while the wiping web110is being wrapped about the first front-stage guide160, the pressing roller118, the first rear-stage guide164and the drive roller124.

More specifically, firstly, the winding core110A on which the wiping web110is wound in the form of a roll is installed on the supply reel138.

Thereupon, the wiping web110is unwound by a prescribed amount from the winding core110A, passed below the second front-stage guide162and the second rear-stage guide166, and also wrapped about the upper side of the first front-stage guide160, the pressing roller118and the first rear-stage guide164. At this time, the wiping web110is wrapped about the first front-stage guide160, the pressing roller118and the first rear-stage guide164while the elevator stage170is in the lowered state, in other words, while the first front-stage guide160, the pressing roller118and the first rear-stage guide164are in the downwardly retracted state. Thereby, it is possible to ensure sufficient space with respect to the second front-stage guide162and the second front-stage guide166, and the wiping web110can be easily wrapped about the first front-stage guide160, the pressing roller118and the first rear-stage guide164by passing below the second front-stage guide162and the second rear-stage guide166.

The wiping web110wrapped about the first front-stage guide160, the pressing roller118and the first rear-stage guide164is further wrapped about the drive roller124, and finally the winding core110B on the leading end thereof is installed on the take-up reel142. Thus, installation of the wiping web110is completed. Thereafter, the wiping web110is wound back onto the winding core110A as necessary, thereby eliminating slack in the wiping web110, and the lid128of the case112is then closed.

Next, the wiping unit100in which the wiping web110has been installed in set in the rack102.

The wiping unit100is set in the rack102by vertically inserting the wiping unit100into the installation section104formed in the rack102.

When the wiping unit100has been set in the installation section104of the rack102, as shown inFIG. 17B, the idle gear188of the wiping unit100meshes with the drive gear192arranged on the installation section72, and thus becomes rotatably drivable by the motor194, which is coupled to the drive gear192.

Furthermore, when the wiping unit100is set in the installation section104of the rack102, the elevator lever178arranged on the elevator stage170engages with the pin182arranged on the installation section104, and the elevator stage170is forcibly raised up to the prescribed position. Thereby, the first front-stage guide160, the pressing roller118and the first rear-stage guide164are registered in the prescribed use position. By registering the first front-stage guide160, the pressing roller118and the first rear-stage guide164in the prescribed use position, the wiping web110becomes wrapped about the second front-stage guide162, which is disposed between the first front-stage guide160and the pressing roller118, and furthermore the wiping web110also becomes wrapped about the second rear-stage guide166, which is disposed between the pressing roller118and the first rear-stage guide164. Thereby, the wiping web110is tautly wrapped about the circumferential surface of the pressing roller118.

Thus, the setting of the wiping unit100in the rack102is completed.

In the thus set wiping unit100in the rack102, by driving the motor194, the wiping web110is supplied from the supply spindle114and taken up onto the take-up spindle116after passing along a prescribed path of travel.

Furthermore, as shown inFIG. 8, the pressing rollers118of the wiping units100C,100M,100Y and100K, which correspond respectively to the inkjet heads16C,16M,16Y and16K disposed with their nozzle surfaces30C,30M,30Y and30K at the inclinations with respect to the horizontal plane, are positioned in parallel with the nozzle surfaces30C,30M,30Y and30K, respectively. Thus, it is possible to cause the wiping webs110wrapped about the respective pressing rollers118to make tight contact with the corresponding nozzle surfaces30C,30M,30Y and30K.

Similarly to the cleaning liquid deposition device62, the wiping device64wipes and cleans the nozzle surfaces30(30C,30M,30Y,30K) of the inkjet heads16(16C,16M,16Y,16K) while the inkjet heads move from the image recording position to the maintenance position. More specifically, the nozzle surfaces are wiped as follows.

The whole of the wiping device64is arranged raisable and lowerable. When not performing cleaning, the wiping device64is disposed in a prescribed standby position. During cleaning, the wiping apparatus64is raised by a prescribed amount from the standby position to a prescribed operating position.

When the wiping device64is moved to the operating position, the nozzle surfaces30C,30M,30Y and30K of the inkjet heads16C,16M,16Y and16K can be wiped by the wiping units100C,100M,100Y and100K. More specifically, when the inkjet heads16C,16M,16Y and16K pass the respective wiping units100C,100M,100Y and100K, it is possible for the wiping webs110wound about the pressing rollers118to abut and press against the nozzle surfaces30C,30M,30Y and30K.

When the inkjet heads16C,16M,16Y and16K in which the cleaning liquid has been deposited on the nozzle surfaces30C,30M,30Y and30K by the cleaning liquid deposition device62are moved in this state toward the maintenance position, during the course of this movement, the wiping webs110abut and press against the nozzle surfaces30C,30M,30Y and30K.

The controller drives the motors194and causes the wiping webs110to travel, in accordance with the timing at which the inkjet heads16C,16M,16Y and16K arrive at the wiping units100C,100M,100Y and100K. Thereby, the traveling wiping webs110abut and press against the nozzle surfaces30C,30M,30Y and30K, thus wiping and cleaning the nozzle surfaces30C,30M,30Y and30K.

In this operation, since the excess cleaning liquid has been removed from the nozzle surfaces30C,30M,30Y and30K, then it is possible to wipe the nozzle surfaces30C,30M,30Y and30K reliably, without any decline in the absorbing capability of the wiping webs110.

<Action of Nozzle Surface Cleaning Apparatus>

The nozzle surface cleaning apparatus60according to the present embodiment is composed as described above.

Next, a nozzle surface cleaning operation performed by the nozzle surface cleaning apparatus60in the present embodiment is described.

The cleaning of the nozzle surfaces is performed while the inkjet heads16C,16M,16Y and16K are moved from the image recording position to the maintenance position.

When a nozzle surface cleaning instruction is input to the controller, the controller moves the cleaning liquid deposition device62and the wiping device64to the prescribed operating positions. By this means, deposition of the cleaning liquid and wiping become possible.

After the cleaning liquid deposition device62and the wiping device64are moved to the prescribed operating positions, the controller causes the head supporting frame40to move from the image recording position to the maintenance position at a prescribed movement speed.

On the other hand, the controller also drives the cleaning liquid supply pump228in accordance with the timing at which the inkjet heads16C,16M,16Y and16K arrive at the cleaning liquid deposition heads210of the cleaning liquid deposition units200C,200M,200Y and200K. Thereby, the cleaning liquid flows out at a prescribed flow rate from the cleaning liquid emission ports218of the cleaning liquid deposition heads210in the respective cleaning liquid deposition units200C,200M,200Y and200K. The cleaning liquid which has flowed out from the cleaning liquid emission ports218flows down over the cleaning liquid holding surfaces216.

When the inkjet heads16C,16M,16Y and16K moving toward the maintenance position pass the cleaning liquid deposition heads210, the cleaning liquid which has flowed over the cleaning liquid holding surfaces216of the cleaning liquid deposition heads210contacts the nozzle surfaces30C,30M,30Y and30K, and the cleaning liquid is thereby deposited on the nozzle surfaces30C,30M,30Y and30K.

Thereupon, the squeegees212are pressed against the lower edge portions of the nozzle surfaces30C,30M,30Y and30K on which the cleaning liquid has been deposited, and excess cleaning liquid which collects in the lower edge portions in the direction of inclination is swept with the squeegees212.

The inkjet heads16C,16M,16Y and16K from the nozzle surfaces of which excess cleaning liquid has been swept are then moved toward the maintenance position and during the course of this movement, the wiping webs110are pressed against the nozzle surfaces30C,30M,30Y and30K.

The controller drives the motors194and causes the wiping webs110to travel, in accordance with the timing at which the inkjet heads16C,16M,16Y and16K arrive at the wiping units100C,100M,100Y and100K. Thereby, the traveling wiping webs110abut and press against the nozzle surfaces30C,30M,30Y and30K, thus wiping and cleaning the nozzle surfaces30C,30M,30Y and30K.

When the nozzle surfaces30C,30M,30Y and30K have completely passed the cleaning liquid deposition units200C,200M,200Y and200K, the driving of the cleaning liquid supply pump228is halted and the supply of cleaning liquid is halted. Thereupon, the cleaning liquid deposition device62is withdrawn to the standby position.

When the nozzle surfaces30C,30M,30Y and30K have completely passed the wiping units100C,100M,100Y and100K, the driving of the motors194is halted and the travel of the wiping webs110is halted. Thereupon, the wiping device64is withdrawn to the standby position.

The cleaning of the nozzle surfaces30C,30M,30Y and30K of the inkjet heads16C,16M,16Y and16K is completed by the series of steps described above.

As described above, in the nozzle surface cleaning apparatus60according to the present embodiment, when the cleaning liquid has been deposited onto the nozzle surfaces30C,30M,30Y and30K from the cleaning liquid deposition heads210in the cleaning liquid deposition device62, the excess cleaning liquid which collects on the lower edge portions of the nozzle surfaces30C,30M,30Y and30K in the direction of inclination is swept with the squeegees212. Thereby, it is possible to prevent excess cleaning liquid from dripping down during movement of the inkjet heads and soiling the peripheral area. Furthermore, it is possible to prevent the wiping capability of the wiping webs110declining with the wiping step in the latter stage and giving rise to insufficient wiping. In particular, this is especially useful when using wiping webs110having absorbency, since they display marked decline in the absorption capacity due to the presence of residual excess cleaning liquid.

In the above-described embodiment, the squeegees212are composed to abut only against the nozzle surfaces30; however, it is desirable that as shown inFIG. 18, the tip portion of each squeegee212is formed in a V-shape and the squeegee212also abuts against the side wall surface of the inkjet head on the lower side of the direction of inclination. By this means, it is possible to remove the excess cleaning liquid more reliably. More specifically, since the excess cleaning liquid may descend and bend back inside the side wall surface, then it is possible to remove the excess cleaning liquid which has collected in the lower edge portions of the direction of inclination, in a more reliable way, by pressing the squeegee212against the side wall surface also.

Furthermore, in the present embodiment, the cleaning liquid deposition head210and the squeegee212are integrally installed on the cleaning liquid recovery tray214, but the cleaning liquid deposition head210and the squeegee212can be composed separately.

Second Embodiment

In the nozzle surface cleaning apparatus according to the first embodiment of the present invention, the composition is adopted in which the excess cleaning liquid is removed from the nozzle surface30by sweeping with the squeegee212, the excess cleaning liquid which has collected on the lower edge portion of the nozzle surface30in the direction of inclination.

In the nozzle surface cleaning apparatus according to the second embodiment of the present invention, the excess cleaning liquid which has collected on the lower edge portion of the nozzle surface30in the direction of inclination is removed by suctioning. Apart from the composition for removing the excess cleaning liquid, the composition of the nozzle surface cleaning apparatus in the second embodiment is the same as the nozzle surface cleaning apparatus in the above-described first embodiment, and therefore only the composition for suctioning and removing the excess cleaning liquid is described here.

FIG. 19is a front view diagram showing a composition of the cleaning liquid deposition unit300which is arranged in the nozzle surface cleaning apparatus according to the second embodiment.FIG. 20is a side view diagram showing the cleaning liquid deposition unit300viewed from the maintenance position side.

As shown inFIG. 19, a suction nozzle310is arranged instead of a squeegee in the cleaning liquid deposition unit300according to the present embodiment.

The suction nozzle310is vertically erected by being installed on a suction nozzle installation section312, which is arranged inside the cleaning liquid recovery tray214. The suction nozzle310is disposed so as to correspond to the position of the lower edge portion, in the direction of inclination, of the nozzle surface30that is being cleaned, and the upper end portion of the suction nozzle310is formed at an inclination corresponding to the angle of inclination of the nozzle surface30being cleaned.

A suction aperture310A is formed on the upper end surface of the suction nozzle310, and excess cleaning liquid which has collected on the lower edge portion of the nozzle surface30in the direction of inclination is suctioned through the suction aperture310A.

The suction nozzle310is connected to the cleaning liquid recovery tank240through a suction channel314. A suction pump316is arranged at an intermediate point of the suction channel314, and by driving the suction pump316, excess cleaning liquid is suctioned through the suction nozzle310. The excess cleaning liquid suctioned through the suction nozzle310is recovered into the cleaning liquid recovery tank240through the suction channel314.

A controller, which is not illustrated, controls the driving of the suction pump316and thereby controls the suctioning operation of the excess cleaning liquid by the suction nozzle310.

The action of the cleaning liquid deposition unit300according to the present embodiment which has the composition described above is as follows.

When the cleaning liquid deposition unit300is set to the prescribed cleaning liquid deposition position, it is possible to suction and remove the excess cleaning liquid which has collected in the lower edge portion of the nozzle surface30in each of the inkjet heads, by means of the suction head310. In other words, when the cleaning liquid deposition unit300is set to the cleaning liquid deposition position, the suction nozzle310is set to the position where it is possible to suction excess cleaning liquid which collects in the lower edge portion of the nozzle surface in the direction of inclination. More specifically, the suction nozzle310is set to the position which opposes the lower edge portion of the nozzle surface30in the direction of inclination, at a prescribed distance from same.

The deposition of the cleaning liquid is similar to the cleaning liquid deposition in the first embodiment. In other words, the cleaning liquid supply pump228is driven at the timing of the arrival of the inkjet head, the nozzle surface30is made to contact the cleaning liquid which has flowed down the cleaning liquid holding surface216, and the cleaning liquid is thereby deposited onto the nozzle surface30.

On the other hand, the removal of excess cleaning liquid is performed as described below.

The controller drives the suction pump316in accordance with the timing at which the inkjet head arrives at the suction nozzle310. By this means, when the nozzle surface30passes the installation position of the suction nozzle310, the lower edge portion of the nozzle surface30in the direction of inclination is applied with suction by the suction nozzle310, and the excess cleaning liquid having been collected thereon is suctioned through the suction nozzle310. Thereby, it is possible to remove the excess cleaning liquid.

Thus, in the nozzle surface cleaning apparatus according to the present embodiment, the excess cleaning liquid which has collected on the lower edge portion of the nozzle surface30in the direction of inclination is removed by suctioning through the suction nozzle310. By this means, similarly to the nozzle surface cleaning apparatus according to the first embodiment described above, it is possible to prevent the excess cleaning liquid from dripping down during movement of the inkjet head and soiling the peripheral area. Furthermore, it is possible to prevent the wiping capability of the wiping webs110declining with the wiping step in the latter stage and giving rise to insufficient wiping.

It is desirable that the suction nozzle310of the present embodiment has a tip section formed in a V-shape and a suction hole faces also the side wall surface on the lower side of the inkjet head in the direction of inclination. Thereby, it is possible to remove the excess cleaning liquid more reliably.

Furthermore, in the nozzle surface cleaning apparatus according to the present embodiment, the cleaning liquid deposition head210and the suction nozzle310may also be arranged separately.

Third Embodiment

FIG. 21is a front view diagram showing a composition of a cleaning liquid deposition unit400which is arranged in the nozzle surface cleaning apparatus according to a third embodiment of the present invention.

The nozzle surface cleaning apparatus in the present embodiment is capable of switching the types of cleaning liquid deposited on the nozzle surface30.

Apart from being devised so as to switch the cleaning liquid to be deposited, the composition of the cleaning liquid deposition unit400in the second embodiment is the same as the cleaning liquid deposition unit200in the above-described first embodiment, and therefore only the composition which enables switching of the cleaning liquid to be deposited is described here.

The cleaning liquid supply channel224is connected to the cleaning liquid support port222, which is connected to the cleaning liquid deposition head210. The cleaning liquid supply channel224is formed to branch into a first cleaning liquid supply channel224A and a second cleaning liquid supply channel224B at an intermediate point thereof.

The first cleaning liquid supply channel224A is connected to a first cleaning liquid supply tank226A, and a first cleaning liquid supply pump228A and a first valve410A are arranged at an intermediate point of the channel.

On the other hand, the second cleaning liquid supply channel224B is connected to a second cleaning liquid supply tank226B, and a second cleaning liquid supply pump228B and a second valve410B are arranged at an intermediate point of the channel.

Different types of cleaning liquid are stored respectively in the first cleaning liquid supply tank226A and the second cleaning liquid supply tank226B. In other words, a first cleaning liquid is stored in the first cleaning liquid supply tank226A and a second cleaning liquid is stored in the second cleaning liquid supply tank226B. In the present embodiment, normal cleaning liquid is used for the first cleaning liquid and diluted cleaning liquid is used for the second cleaning liquid.

The controller switches the cleaning liquid to be deposited onto the nozzle surface by controlling the driving of the first cleaning liquid supply pump228A and the second cleaning liquid supply pump228B, and the driving of the first valve410A and the second valve410B.

More specifically, when depositing the first cleaning liquid, the first valve410A is opened, the second valve410B is closed, and the first cleaning liquid supply pump228A is driven. Thereby, the first cleaning liquid, which is stored in the first cleaning liquid supply tank226A, is sent to the cleaning liquid deposition head210and the first cleaning liquid flows out from the cleaning liquid emission port218of the cleaning liquid deposition head210.

On the other hand, when depositing the second cleaning liquid, the second valve410B is opened, the first valve410A is closed, and the second cleaning liquid supply pump228B is driven. Thereby, the second cleaning liquid, which is stored in the second cleaning liquid supply tank226B, is sent to the cleaning liquid deposition head210and the second cleaning liquid flows out from the cleaning liquid emission port218of the cleaning liquid deposition head210.

Thus, according to the nozzle surface cleaning apparatus of the present embodiment, it is possible to switch the types of cleaning liquid deposited on the nozzle surface30. By this means, it is possible to use suitable cleaning liquid in accordance with the extent of soiling of the nozzle surface30, and the nozzle surface30can be cleaned efficiently. More specifically, for example, if the extent of soiling is high, then cleaning is performed using the first cleaning liquid, and if the extent of soiling is low, then cleaning is performed using the second cleaning liquid, whereby it is possible to clean the nozzle surface30efficiently in accordance with the extent of soiling.

Fourth Embodiment

FIG. 22is a front view diagram showing a composition of a cleaning liquid deposition unit500which is arranged in the nozzle surface cleaning apparatus according to the fourth embodiment of the present invention.

The cleaning liquid deposition unit500in the present embodiment differs from the cleaning liquid deposition unit200in the first embodiment described above in that a plurality of cleaning liquid deposition heads are arranged. Consequently, only this point is described here.

As shown inFIG. 22, in the cleaning liquid deposition unit500according to the present embodiment, the first cleaning liquid deposition head210A and the second cleaning liquid deposition head210B, which have the same composition, are arranged in parallel in the direction of movement of the inkjet head. More specifically, the first cleaning liquid deposition head210A is on the image recording position side, and the second cleaning liquid deposition head210B is on the maintenance position side.

In this case, the squeegee212is arranged to the side of the maintenance position from the second cleaning liquid deposition head210B.

The composition of the first cleaning liquid deposition head210A and the second cleaning liquid deposition head210B is the same as the composition of the cleaning liquid deposition head210in the first embodiment which has been described above. In other words, each of the first and second cleaning liquid deposition heads210A and210B is formed in a rectangular block shape having an inclined upper surface, and a cleaning liquid holding surface parallel to the nozzle surface30is formed on top of same. The cleaning liquid holding surface of the first cleaning liquid deposition head210A is taken to be a first cleaning liquid holding surface216A, and the cleaning liquid holding surface of the second cleaning liquid deposition head210B is taken to be a second cleaning liquid holding surface216B.

Furthermore, the cleaning liquid emission port is formed in the vicinity of the upper part of the cleaning liquid holding surface, and the cleaning liquid flows out from the cleaning liquid emission port. The cleaning liquid emission port of the first cleaning liquid deposition head210A is taken to be a first cleaning liquid emission port218A, and the cleaning liquid emission port of the second cleaning liquid deposition head210B is taken to be a second cleaning liquid emission port218B.

The cleaning liquid supply flow channel connected to the cleaning liquid emission port is formed inside the cleaning liquid deposition head. The cleaning liquid supply flow channel of the first cleaning liquid deposition head210A is taken to be a first cleaning liquid supply flow channel220A, and the cleaning liquid supply flow channel of the second cleaning liquid deposition head210B is taken to be a second cleaning liquid supply flow channel220B.

A first connection flow channel221A, which connects to the first cleaning liquid supply flow channel220A, and a second connection flow channel221B, which connects to the second cleaning liquid supply flow channel220B, are formed in the cleaning liquid recovery tray214, and furthermore a first cleaning liquid supply port222A, which connects to the first connection flow channel221A, and a second cleaning liquid supply port222B, which connects to the second connection flow channel221B, are also formed in the cleaning liquid recovery tray214.

The first cleaning liquid supply tank226A is connected to the first cleaning liquid supply port222A through the first cleaning liquid supply channel224A. The first cleaning liquid supply pump228A is arranged at an intermediate point of the first cleaning liquid supply channel224A, and by driving the first cleaning liquid supply pump228A, the first cleaning liquid stored in the first cleaning liquid supply tank226A is supplied to the first cleaning liquid supply port222A. Due to the first cleaning liquid being supplied to the first cleaning liquid supply port222A, the first cleaning liquid flows out from the first cleaning liquid emission port218A of the first cleaning liquid deposition head210A.

On the other hand, the second cleaning liquid tank226B is connected to the second cleaning liquid supply port222B through the second cleaning liquid supply channel224B. The second cleaning liquid supply pump228B is arranged at an intermediate point of the second cleaning liquid supply channel224B, and by driving the second cleaning liquid supply pump228B, the second cleaning liquid stored in the second cleaning liquid supply tank226B is supplied to the second cleaning liquid supply port222B. Due to the second cleaning liquid being supplied to the second cleaning liquid supply port222B, the second cleaning liquid flows out from the second cleaning liquid emission port218B of the second cleaning liquid deposition head210B.

A controller, which is not illustrated, controls the driving of the first cleaning liquid supply pump228A and the second cleaning liquid supply pump228B, so as to control the supply of the first cleaning liquid to the first cleaning liquid deposition head210A and the supply of the second cleaning liquid to the second cleaning liquid deposition head210B.

According to the cleaning liquid deposition unit500in the present embodiment which is composed as described above, it is possible to alter the deposition volume and/or the type of cleaning liquid which is deposited on the nozzle surface30. Thereby, it is possible to deposit the cleaning liquid appropriately, in accordance with the extent of soiling of the nozzle surface30.

For example, if the cleaning liquid of the same type is stored in the first cleaning liquid supply tank226A and the second cleaning liquid supply tank226B (namely, if the first cleaning liquid is the same as the second cleaning liquid), then it is possible to deposit an appropriate amount of the cleaning liquid in accordance with the extent of soiling, by altering the number of cleaning liquid deposition heads used in accordance with the extent of soiling. For example, if there is little soiling, then the cleaning liquid is deposited on the nozzle surface30by using only one of the first cleaning liquid deposition head210A and the second cleaning liquid deposition head210B. On the other hand, if there is a large amount of soiling, then the cleaning liquid is deposited onto the nozzle surface30by using both the first cleaning liquid deposition head210A and second cleaning liquid deposition head210B.

Furthermore, for example, if the cleaning liquids of different types are stored in the first cleaning liquid supply tank226A and the second cleaning liquid supply tank226B (namely, if the first cleaning liquid is not the same as the second cleaning liquid), then it is possible to deposit an appropriate cleaning liquid in accordance with the extent of soiling, by being able to alter the cleaning liquid deposition head used in accordance with the extent of soiling. For instance, the normal cleaning liquid (first cleaning liquid) is stored in the first cleaning liquid supply tank226A and the diluted cleaning liquid (second cleaning liquid) is stored in the second cleaning liquid supply tank226B, and if there is little soiling, then the diluted cleaning liquid (second cleaning liquid) is deposited onto the nozzle surface30using the second cleaning liquid deposition head210B. On the other hand, if there is a large amount of soiling, then the normal cleaning liquid (first cleaning liquid) is deposited onto the nozzle surface30by using the first cleaning liquid deposition head210A.

In this way, according to the nozzle surface cleaning apparatus of the present embodiment, it is possible to switch the deposited amount and/or the type of cleaning liquid deposited on the nozzle surface30, by providing the plurality of cleaning liquid deposition heads. Thus, it is possible to use a suitable volume or a suitable type of cleaning liquid in accordance with the extent of soiling of the nozzle surface30, and the nozzle surface30can be cleaned efficiently. Moreover, it is also possible to restrict wasteful consumption of the cleaning liquid.

In the present embodiment, an example is described in which two cleaning liquid deposition heads are arranged, but the number of the cleaning liquid deposition heads arranged is not limited to this. Furthermore, in the present embodiment, the two cleaning liquid deposition heads are composed separately, but it is also possible to adopt a composition in which a plurality of cleaning liquid emission ports are arranged in a single cleaning liquid deposition head.

Fifth Embodiment

The nozzle surface cleaning apparatus according to the fifth embodiment of the present invention varies the speed of movement of the inkjet head (speed of movement of the head supporting frame) in accordance with the extent of soiling of the nozzle surface. In other words, when the speed of movement of the inkjet head is changed, the time from the deposition of the cleaning liquid by the cleaning liquid deposition device62until the wiping by the wiping device64changes, the time during which the cleaning liquid is present on the nozzle surface changes, and therefore the cleaning capability also varies.

Consequently, it is possible to clean the nozzle surface appropriately by changing the speed of movement of the inkjet head in accordance with the extent of soiling of the nozzle surface. For example, if there is a large amount of soiling, the speed of movement of the inkjet head is slowed, thereby increasing the time during which the cleaning liquid is present on the nozzle surface and raising the cleaning properties.

Apart from being able to change the speed of movement of the inkjet head, the composition of the nozzle surface cleaning apparatus in the fifth embodiment is the same as that of the nozzle surface cleaning apparatus in the above-described first embodiment, and therefore only the cleaning method is described here.

As stated previously, the head supporting frame40on which the inkjet heads16C,16M,16Y and16K are installed is driven by the linear drive mechanism (for example, the screw feed mechanism, or the like), which is not illustrated, and thereby moved between the image recording position and the maintenance position. The present embodiment adopts a composition whereby the speed of movement of the head supporting frame40can be altered (for example, if the linear drive mechanism is constituted of the screw feed mechanism, then the speed of rotation of the feed screw is variable). The linear drive mechanism moves the inkjet heads16C,16M,16Y and16K (by moving the head supporting frame40) at a speed of movement corresponding to an instruction from the controller.

In the present embodiment, a composition is adopted in which the inkjet heads16C,16M,16Y and16K can be moved at either at a first speed of movement V1or a second speed of movement V2(V1>V2).

FIG. 23is a table showing cleaning patterns implemented by the control unit.

As shown inFIG. 23, during normal cleaning, the inkjet heads16C,16M,16Y and16K are moved at the first movement speed V1. On the other hand, if there is a large amount of soiling, then the inkjet heads16C,16M,16Y and16K are moved at the second movement speed V2, which is slower than the first movement speed V1.

As described above, by slowing the speed of movement of the inkjet heads16C,16M,16Y and16K, the time from deposition of the cleaning liquid by the cleaning liquid deposition device62until wiping by the wiping device64becomes longer, and the time during which the cleaning liquid is present on the nozzle surface30can be increased. Thereby, it is possible to clean the nozzle surface30in an appropriate manner.

Thus, in the nozzle surface cleaning apparatus according to the present embodiment, it is possible to clean the nozzle surface appropriately by changing the speed of movement of the inkjet head in accordance with the extent of soiling of the nozzle surface.

In the example described above, the speed of movement of the inkjet head can be changed in two stages, but it is also possible to change the speed of movement in a greater number of stages. Furthermore, it is also possible to adopt a composition where a desired speed of movement can be set manually by an operator.

Moreover, in the example described above, the fifth embodiment is implemented in the nozzle surface cleaning apparatus which is provided with only one cleaning liquid deposition head (e.g., the nozzle surface cleaning apparatus according to the first embodiment), but it may also be implemented as described below in the nozzle surface cleaning apparatus which is provided with a plurality of cleaning liquid deposition heads.

FIG. 24is a table showing cleaning patterns implemented by the controller in the nozzle surface cleaning apparatus which is provided with two cleaning liquid deposition heads (e.g., the nozzle surface cleaning apparatus according to the fourth embodiment).

In the present example, the cleaning liquid of the same type is deposited from the first cleaning liquid deposition head210A and the second cleaning liquid deposition head210B.

As shown inFIG. 23, during normal cleaning, the inkjet heads16C,16M,16Y and16K are moved at the first movement speed V1, and the cleaning liquid is deposited from only the first cleaning liquid deposition head210A.

On the other hand, during strong cleaning, the inkjet heads16C,16M,16Y and16K are moved at the second movement speed V2slower than the first movement speed V1, and the cleaning liquid is deposited from only the first cleaning liquid deposition head210A.

Moreover, during finishing cleaning, the inkjet heads16C,16M,16Y and16K are moved at the first movement speed V1, and the cleaning liquid is deposited from both the first cleaning liquid deposition head210A and the second cleaning liquid deposition head210B.

Moreover, during strong finishing cleaning, the inkjet heads16C,16M,16Y and16K are moved at the second movement speed V2, and the cleaning liquid is deposited from both the first cleaning liquid deposition head210A and the second cleaning liquid deposition head210B.

In this way, it is possible to clean the nozzle surface more appropriately, by changing the combination of the number of cleaning liquid deposition heads used and the speed of movement of the inkjet heads.

In the example described above, the case is given in which the cleaning liquid of the same type is deposited from the first cleaning liquid deposition head210A and the second cleaning liquid deposition head210B, but it is also possible to deposit cleaning liquids of different types.

Other Embodiments

In the series of embodiments described above, the composition is adopted in which the nozzle surface cleaning apparatus60is fixed and the inkjet heads16are moved to perform deposition of the cleaning liquid and wiping, but it is also possible to adopt a composition in which the deposition of cleaning liquid and wiping are performed by moving the nozzle surface cleaning apparatus60. Similarly, it is also possible to adopt a composition in which deposition of the cleaning liquid and wiping are performed by moving both the nozzle surface cleaning apparatus and the inkjet head. In this case, the nozzle surface cleaning apparatus60may be composed in such a manner that the cleaning liquid deposition device62and the wiping device64are moved in unison, or are moved separately.

Furthermore, in the series of embodiments described above, the case where the present invention is applied to the inkjet recording apparatus which records images on cut sheet of paper has been described, but the application of the present invention is not limited to this. The present invention can be applied similarly to any droplet ejection apparatus having a composition in which the nozzle surface of a droplet ejection head is inclined with respect to the horizontal plane, and in this case, similar action and beneficial effects can be achieved.