Wiping apparatus for print head

A wiping apparatus for a print head for wiping a head surface of the print head by rubbing the same with a blade is provided that includes a wiping box having a top open area; a blade support having the blade fastened thereto and disposed in an upper part of the wiping box so as to be rotatable between a wiping position at which a tip of the blade points upwards and a storage position at which the tip of the blade points downwards; leakproof plates fastened to the blade support for closing the top open area of the wiping box while the blade is in a state of the storage position; and a cleaning liquid nozzle disposed in the wiping box so that it is directed towards the blade in the storage position.

TECHNICAL FIELD

The present invention relates to an apparatus for wiping a head surface of a print head for use in an ink jet printer by rubbing the same with a blade, that is, a wiping apparatus for such a print head which renders the blade washable after wiping.

BACKGROUND ART

In a print head for an ink jet printer when loaded with ink or purged of ink by sucking ink through a head surface, ink adheres to the head surface. Accordingly, it is customary to wipe the head surface of the print head from time to time with a wiping apparatus attached to the ink jet printer.

In such a wiping apparatus, if ink adhering to the blade after wiping is left as it is, there is a fear that ink made high in viscosity or contaminants adhering together with ink which move to the head surface of the print head come to clog a nozzle.

In order to prevent this, it is customary that the blade which has wiped the head surface of the print head is flushed with a cleaning liquid from a nozzle and the cleaning liquid that adheres to the blade is wiped off by a wiping member (see, e.g., JP P 2005-319654 A). It is also customary that the blade after its wiping operation is immersed in a cleaning liquid for washing and then dried by a drying means (see, e.g., JP P H10-95125 A).

These conventional apparatuses have the problem that below the print head, they are exposed to the surroundings so that the cleaning liquid comes to be scattered into the environment. Especially in the former apparatus of the prior art in which the cleaning liquid is flushed from the nozzle and the liquid wiping is performed by a rotating wiping roll, there is the problem of scattering of the cleaning liquid. In the latter apparatus of the prior art, the drying efficiency was poor since the liquid is drawn and dried by the suction force of a suction pump. Furthermore, in both these apparatus, there was a fear that contaminants may adhere to the blade while not in use.

With the foregoing taken into account, it is an object of the present invention to provide a wiping apparatus for a print head which prevents scattering of a cleaning liquid when cleaning, allows drying after cleaning efficiently and prevents contaminants from adhering to the blade while not in use.

DISCLOSURE OF THE INVENTION

In order to achieve the object mentioned above, there is provided in accordance with the present invention in a first form of implementation thereof a wiping apparatus for a print head for wiping a head surface of the print head by rubbing the same with a blade, characterized in that it comprises: a wiping box having an open area at its top; a blade support having the blade fastened thereto and disposed in an upper part of the wiping box so as to be rotatable over between a wiping position at which a tip of the blade points upwards and a storage position at which the tip of the blade points downwards; a leakproof plate means fastened to the blade support for closing the top open area of the wiping box while the blade is in a state of the storage position; and a cleaning liquid nozzle disposed in the wiping box so that it is directed towards the blade in the storage position.

The present invention also provides in a second form of implementation thereof a wiping apparatus for a print head of the makeup mentioned above which further comprises an air nozzle disposed in the wiping box so that it is directed towards the blade in the storage position.

According to the first form of implementation of the invention described above which requires that the open area of the wiping box be closed with the leakproof plate means when the blade is moved to the storage position at which the blade points downwards to be washed, the cleaning liquid, if flushed forcibly from the cleaning liquid nozzle for washing the blade in this state, is prevented from running out through the upper part of the wiping box or scattering into the surroundings; it is possible to prevent the environment from becoming worse while a print head is cleaned up.

Also, holding the blade in the storage position within the wiping box whose open area is closed prevents contaminants from attaching to the blade while not in use prior to a wiping operation.

According to the second form of implementation of the invention described above, it is possible to dry the blade in the storage position with air from the air nozzle, to perform the drying with air within the wiping box immediately after flushing with the cleaning liquid without the latter scattered into the environment and to execute the washing and drying efficiently.

BEST MODES FOR CARRYING OUT THE INVENTION

FIG. 1is an explanatory view diagrammatically illustrating an ink jet printer. InFIG. 1, there are shown a conveyer unit1for conveying a substrate in a direction perpendicular toFIG. 1and a print head2reciprocating in a transverse direction with respect to the conveyer unit1for printing on the substrate. The print head2is supported via a base mount4on a guide rail3mounted on a frame and is designed to be reciprocated by a drive unit (not shown). The print head2is also movable vertically with respect to the base mount4.

The guide rail3is extended to and mounted over a maintenance section provided laterally of the conveyer unit1so that the print head2may be moved to above a purging unit5mounted on the maintenance section. And, between the purging and conveyer units5and1there is disposed a wiping apparatus6such that when the print head2having its head surface2athrough which ink is purged by the purging unit5is returned toward a printing position above the conveyer unit1, the nozzle surface2ais rubbed with a blade7of the wiping apparatus6and thereby wiped.

Referring now toFIG. 2ff, mention is made of the wiping apparatus6.FIG. 2is a cross sectional view, in part cut away, of the printer including the wiping apparatus along the line II-II inFIG. 1wherein an example using two wiping boxes8is shown. This is one in which two rows of print heads2each as shown inFIG. 1are provided. And, the two wiping boxes8are identical in construction to each other, of one of which mention is made below.FIG. 3is a plan view of the wiping apparatus;FIG. 4is a cross sectional view of the wiping apparatus taken along the line IV-IV inFIG. 2; andFIGS. 5A and 5Bare enlarged cross sectional views of the wiping apparatus taken along the line V-V.

A rotating shaft9is passed through and rotatably supported by the upper part of the wiping box8in a direction perpendicular to that in which the print head2is moved. And, the rotating shaft9has a blade support10fastened thereto to which the blade7is fastened so that it towards its upper side has a tilt to the conveyer unit1in the direction in which the print head2is moved. The blade7is made a little longer than a width of the head surface2aof the print head2. Further, the blade7is made of a plate material such as hard rubber or the like having a suitable elasticity.

The blade support10has a length such that its both ends are in contact with inner side surfaces of the wiping box8. And, the blade support10as shown inFIGS. 5A and 5Bhas a support member11fastened thereto, of which support pieces11aand11bare extended to and disposed at both sides around the rotary axis9, and leak-proof plates12aand12bare fastened to the support pieces11aand11bof the support member11by bolts13.

Rotating the rotating shaft9causes the blade support10to rotate from a wiping position as shown inFIG. 5Aat which the blade7projects upwards to a storage position as shown inFIG. 5Bat which the blade7points downwards by about 180 degrees. And, the two leakproof plates12aand12bwhen the blade support10lies at least at the storage position are oriented horizontally to hold their ends and side ends in contact with the inner surfaces of the wiping box8, leaving no space between them. Here, the leakproof plates12aand12bmay be made of elastic material such as rubber plate so that their ends and side ends make elastic contact with the inner surfaces of the wiping box8.

Under the wiping box8there is disposed a cleaning fluid nozzle14directed towards the end of the blade in the storage state. A side wall of the wiping box8is formed with an air nozzle15laterally juxtaposed with the tip of the blade7in the storage state as mentioned above.

The wiping box8at its lower end is closed with a bottom plate17having a drain hole16.

The wiping apparatus in this form of implementation comprises two of a wiping box8as mentioned above, and the two wiping boxes8and8as shown inFIG. 2are disposed spacedly with each other and coupled to a frame18so that their blades7and7are opposed to the lower surfaces of print heads2and2, respectively. This frame18is supported by a lifting unit19using an air cylinder. The frame18is also provided at its both ends with guide blocks20and20which are fastened to side walls of the wiping boxes8and8, respectively. And, the guide blocks20and20are slidably fitted with posts22and22standing on a base plate21. The posts22and22are respectively supported by stands23and23which stand on the base plate21and which have top plates23aand23aprovided with stoppers24and24contacting with the upper ends of the guide blocks20and20, respectively. The stopper24and24are each constituted by a bolt whose end position is made adjustable.

A rotary actuator26of 180° rotation is mounted on the frame18via a bracket25and has an output shaft coupled to the rotating shaft9via gears27and28so that when the rotary actuator26is operated to rotate the rotating shaft9, the blades7and7rotate over a range of angles between the wiping position shown inFIG. 5Aand the storage position shown inFIG. 5B.

Mention is made below of an operation of the wiping apparatus6constructed as mentioned above.

The print head2is first purged of ink trough the nozzles on the nozzle surface2aby the purging unit5in the maintenance section. Thereafter, the print head2in returning to the printing position above the conveyer unit1is wiped of the nozzle surface2aby the blade7of the wiping apparatus8.

In the wiping apparatus6during this wiping operation, the rotary actuator26is driven to move the blade7to the wiping position at which it points upwards as shown inFIG. 5while the lifting unit19is driven to move the wiping box8up to a position at which it is restrained by the stopper24. At this move-up position, the head surface2ain contacting with the blade7makes the blade tip moderately bend.

Moving the print head2towards the conveyer unit1in this state causes the nozzle surface2aof the print head2to be rubbed by the blade7of the wiping apparatus6and ink adhering on the nozzle surface2ato be thereby scraped and wiped off. And, as the blade7after the wiping operation has the ink adhering thereon which has been scraped and wiped off from the head surface2a, this is cleaned by a cleaning operation.

The cleaning operation is performed as follows:

The rotary actuator26is driven to move the blade7to the storage position at which it point downwards. In this state as in the wiping position, the leakproof plates12aand12bextends horizontally and their ends and side ends are held in elastic contact with the inner surfaces of the wiping box8so that the upper part of the wiping box8is closed liquid-tight with the leakproof plates12aand12band the both ends of the blade support10.

In this state, a cleaning liquid is first flushed from the cleaning liquid nozzle14. As the cleaning liquid nozzle14is then pointed towards the tip of the blade7in the storage position, the cleaning liquid is then flushed directly on the tip of the blade7to cause the ink adhering on the blade7to be washed off. Then, since as mentioned above the upper part of the wiping box8is closed liquid-tight, the cleaning liquid flushed from the cleaning liquid nozzle14is discharged through the drain hole16without running out through above the wiping box8. The cleaning liquid then used may be purified water as an example. Further, if ink used for the print head2is dye or pigment ink, the cleaning liquid may use water but if it is UV ink, a special type of ink is used.

After the cleaning liquid is flushed over a time period in which to cause the ink adhered on the blade7to be washed out, the flushing is terminated. After then, air is flushed from the air nozzle15to dry the blade7wetted with the cleaning liquid.

The wiping apparatus6other than in the wiping operation is held lowered by the lift-down by the lifting unit19so that the wiping apparatus6is held not to interfere with the head surface2aof the print head2.

While in the forms of implementation described above a wiping apparatus is illustrated for an ink jet printer having two row of print heads2in which two wiping boxes8are arranged in parallel and their respective blades7and7are rotated by a single rotating shaft9, it should be understood that the number of wiping boxes8is provided according to the number of print heads2and that if the ink jet printer is of multi-color type requiring three or more print heads2, a necessary number of wiping boxes8are provided accordingly. The blades7then provided can be operated with a single rotating shaft9as in the structure shown inFIG. 2and can be operated with a single rotary actuator26as well. Further, the lifting unit19may be used in common for them.