Abstract:
An ink jet head capping device provided in an ink jet printer has a cleaning mechanism which performs a brushing operation to remove or wipe ink which has leaked out from an ink nozzle of an ink jet head during a suction operation and which is present on the ink jet head face, and to scrape deposits on the ink jet nozzle and the ink jet head face, which would cause clogging of the ink jet head.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an ink jet head capping device in an ink jet printing apparatus. 
     In a conventional ink jet head capping device, as shown in FIG. 5, a cleaning belt 15 carrying scraping strips 25 is arranged in parallel with, and alongside, a cap 14 and receives a driving force from a driving belt 19 to undergo rotation. An arm 16 supports cleaning belt 15 and cap 14, and is carried by a support shaft 20 to undergo pivotal movement therearound to switch between a capped state and a released state with respect to an ink jet head (not shown) disposed above cap 14. Further, in color ink jet printing, four heads are provided for four printing inks, for example of yellow, magenta, cyan and black, so that three more caps must be added adjacent to the cap 14 of FIG. 5 in parallel to the support shaft 20. Therefore, the apparatus must be enlarged in the axial direction of support shaft 20, i.e. in the printing width direction. In such case, a single cleaning belt is commonly utilized to sequentially effect cleaning of the four color ink nozzles, rather than providing three additional cleaning belts, so as to save space. 
     In the above noted construction, additional space is needed in the axial direction of support shaft 20, and an ink jet capping device must be disposed within the ink jet head printing apparatus but outside the printing region, thereby causing the drawback that the overall dimension of the printing apparatus is enlarged, especially in the widthwise direction of a printing paper sheet. Such drawback is quite disadvantageous in view of the recent demand for miniaturization of the printing apparatus. 
     Further, in case such structure is adapted for color ink jet printing apparatus, a single cleaning belt 15 may be commonly utilized to effect sequential cleaning of respective color inks, since four cleaning belts could not be provided for the four color inks in view of the above noted space limitations. Therefore, previously, cleaned ink of one color may be deposited on an adjacent head for another color to be cleaned, to thereby cause mixing of the inks, resulting in serious degradation of image quality. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to reduce the space required, in the direction of the support shaft axis, for a print head wiping unit. 
     Another object of the invention is to avoid transfer of ink from one print head to another in a color printer. 
     The above and other objects are achieved, according to the present invention, in an ink jet printer which includes a print head having a head face and at least one ink jet ejecting nozzle disposed at the head face for ejecting ink drops in a direction transverse to the head face, by the provision of an ink jet capping device comprising: a cap for covering the nozzle; cap displacement means supporting the cap and movable between a capping position in which the cap contacts the head face and covers the nozzle and an uncapping position in which the cap is spaced from the head face and the nozzle; a cleaning member for wiping ink deposits away from the head face; and cleaning member displacement means carrying the cleaning member and moveable to a stored position which allows movement of the cap displacement means to the capping position, the cleaning member displacement means being operable for moving the cleaning members to wipe the head face subsequent to movement of the cap displacement means from the capping position toward the uncapping position. 
     In the apparatus according to the invention, a wiper member having a cleaning function is disposed along a widthwise direction in parallel to a cap, or a row of caps which can come into contact with respective ink jet heads. In the capped state where extra or leaked ink is absorbed or the ink jet head stays nonoperative, the wiper member held at one end of a cleaning arm is moved to a stored position to avoid interference with the caps and a cap arm which supports the cap. On the other hand, to establish an uncapping state, the caps and cap arm are displaced away from the print head by rotating the cap arm around an arm support shaft. The cleaning arm is rotated around a cleaning arm support shaft to move the wiper member between the ink jet head and the caps. The wiper member carries blades of a specific material effective to remove deposits on ink jet nozzles. The wiper member is displaced to avoid interference with the caps and the cap arm, and thereafter starts to operate to effect cleaning of the head. 
     According to the above described construction, in cooperation with uncapping movement of the cap arm, the cleaning arm operates to act on respective ink jet nozzles on a head face or head faces to clean remaining ink and deposits. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of an embodiment according to the invention. 
     FIG. 2 is a perspective view of the embodiment of FIG. 1. 
     FIG. 3 is a side elevational view showing one operating state of the embodiment of FIG. 1. 
     FIG. 4 is a side elevational view showing several stages of another operating state of the embodiment of FIG. 1. 
     FIG. 5 is a perspective view of a prior art structure. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, an embodiment of the invention will be described with reference to the drawings. Referring to FIGS. 1-3, a wiper member 10 has protruding blades, or strips, 25 effective to scrape ink jet nozzles 1a and an ink jet face 1b of print head 1, and four sets of blades 25 are aligned widthwise, or transverse of the device, corresponding to ink nozzles 1a for four different printing colors. Moreover, wiper member 10 has a plurality of blades 25 for each head 1, arranged in succession effective to improve the scraping or wiping performance. 
     Wiper member 10 is supported by cleaning arms 8 supported, in turn, by a cleaning arm support shaft 11 and rotatable about the axis of shaft 11. Cleaning arms 8 are further biased by a cleaning arm spring 13 in a direction of an escape or restoring position when heads 1 are capped. The cleaning arm 8 has a lateral branch supporting a roller 7 which is in contact with a drive cam 6b such that the cleaning arms 8 undergo pivotal movement in response to clockwise rotation of drive cam 6b. 
     Another drive cam 6a is coaxially supported with the drive cam 6b and is in contact with a roller 5 which is attached to a lateral branch of cap arm 3. Cap arm 3 is mounted for pivotal movement about the axis of another arm support shaft 4 such that the cap arm 3 can undergo pivotal movement around shaft 4 in response to rotation of drive cam 6a. Further, drive cams 6a and 6b are offset from each other along their rotation axis to enable concurrent operation of arms 8 and 3. 
     Cap arm 3 supports at its free end caps 2 such that each cap 2 can cover and seal a corresponding ink jet nozzle 1a in the capped state. Cap arm 3 is biased in the capping direction shown in FIG. 1 by a cap arm spring 12 shown in FIG. 2. Cap arm 3 is pivoted by the rotation of the drive cam 6a to effect closing and opening of cap 2. 
     The operation of the illustrated embodiment will now be described. 
     As shown in FIG. 1, in the capped state, wiper member 10 is restored to a position between arm support shaft 4 and caps 2 so as to avoid interference with caps 2. 
     When opening or releasing caps 2, drive cams 6a and 6b start to rotate in the clockwise direction such that, firstly, cap arm roller 5 moves along a cam face of drive cam 6a to start pivoting of cap arm 3 in the clockwise direction around arm support shaft 4 in the direction of the uncapping state. During this movement, caps 2 move down to a position where they do not interfere with passage of wiper member 10 across faces 1b during pivoting of cleaning arms 8 around cleaning arm support shaft 11. For this purpose, rotating drive cam 6b acts on cleaning arm roller 7 to pivot cleaning arms 8 in the clockwise direction. By the pivoting of cleaning arms 8, wiper member 10 passes between ink jet head 1 and the caps 2 to effect and complete cleaning of the ink jet nozzles 1a and ink jet faces 1b. Several stages in this passage are shown in FIG. 4 and the position of arms 8 at the completion of a cleaning pass is shown in FIG. 3. 
     Further, as shown in FIGS. 2 and 4, two rollers 9 are attached to the top ends of cleaning arms 8. When the wiper member 10 is displaced between the ink jet head 1 and caps 2 during the pivotal movement of the cleaning arms 8, rollers 9 come into sliding contact with the ink jet face 1b to set the height of wiper member 10. Further, as shown in FIG. 4, cleaning arms 8 have respective resilient U-shaped portions just under wiper member 10, effective to easily bend to thereby facilitate the height adjustment of wiper member 10. 
     In this embodiment, blades 25 are made of a rubber material; however, they can be composed advantageously of brush hair or finely slit blades in the form of brushes. 
     By the above described construction, the space required for the capping device can be reduced to thereby permit an overall reduction in size of the ink jet printing apparatus. Further, in color ink jet printing apparatus, a plurality of wiper members can be provided for four different color inks to thereby avoid mixing of the different inks which would be caused in the prior art where a single wiper member is commonly applied to four different ink jet heads, thereby maintaining high quality of printing. 
     This application relates to subject matter disclosed in Japanese Application No. U1-87695, filed on July 25, 1989, the disclosure of which is incorporated herein by reference. 
     While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention. 
     The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather that the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embrace therein.