Abstract:
An image forming apparatus includes a recording head configured to jet droplets of recording liquid; a maintenance device configured to maintain/restore a condition of the recording head, whereby the maintenance device is detachably attached to a body of the image forming apparatus; and a waste liquid tank configured to hold waste liquid collected by the maintenance device, whereby the waste liquid tank is disposed adjacent to the maintenance device. The maintenance device has a jetting tube configured to discharge the waste liquid into the waste liquid tank. The waste liquid tank includes an induction opening surrounding the jetting tube, whereby the induction opening has a notch through which the jetting tube passes when the maintenance device is detached from the body. The image forming apparatus further includes a wall member configured to block at least part of the notch when the maintenance device is attached in the body.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus including a recording head for jetting liquid droplets of recording liquid; a maintenance device that is detachably attached to the apparatus, which is for maintaining/restoring the condition of the recording head; and a waste liquid tank for holding waste liquid that has been collected by the maintenance device, whereby the waste liquid tank is disposed adjacent to the maintenance device. 
         [0003]    2. Description of the Related Art 
         [0004]    There is known an inkjet recording apparatus which is an image forming apparatus such as a printer, a fax machine, a copier, and a multifunction peripheral including printer/fax/copier functions. In the inkjet recording apparatus, a recording head, which is (image forming unit) constituted by a liquid droplet jetting head for jetting liquid droplets of recording liquid, is used for forming images (recording and printing are also used as synonyms) by causing liquid droplets (hereinafter, also referred to as ink droplets) of recording ink to adhere onto a sheet while conveying the sheet. 
         [0005]    There are various types of liquid droplet jetting heads, such as a piezo type, a thermal type, and an electrostatic type. The piezo type uses an electromagnetic transducer element such as a piezoelectric element. The thermal type uses an electrothermal element such as a heat element provided in the jetting head for jetting ink droplets by generating bubbles due to film boiling. The electrostatic type uses an electrostatic force to deform oscillating plates which form walls of a jetting chamber for jetting ink droplets. 
         [0006]    In an inkjet recording apparatus, ink droplets are jetted from fine jetting outlets. Therefore, the jetting outlets may become clogged when the ink dries and the viscosity of the ink increases or the ink solidifies, or when bubbles are generated in the ink. As a result, jetting failures may occur. In order to prevent such jetting failures, there is provided a maintenance device for maintaining the ink jetting function in a normal state and restoring the ink jetting function. 
         [0007]    For example, such a maintenance device includes the following mechanisms. One mechanism is for restoring the jetting outlet by filling the recording head with ink with the use of a pressurizing unit, in the event that a jetting failure occurs due to bubbles that have been generated in the jetting outlet during a recording operation. Another mechanism is for performing preliminary jetting (idle jetting) in preparation for when the viscosity of the ink increases or the ink solidifies due to natural evaporation of the ink in the jetting outlets. Yet another mechanism is for wiping off ink droplets and dust that have adhered to the surface of the jetting outlets. Two or more of these mechanisms may be combined. 
         [0008]    Patent document 1 describes an apparatus in which an outer cover is detachably attached to the backside of the apparatus main body. On the inside of the outer cover, a waste liquid tank for holding waste liquid received from a maintenance/recovery mechanism, is detachably attached to the apparatus main body. The outer cover can be removed to retrieve the waste liquid tank, and provide a new waste liquid tank or reuse the same waste liquid tank. In conjunction with the waste liquid tank and the maintenance device being retrieved from the apparatus main body, the waste liquid tube part is blocked with a shutter mechanism. 
         [0009]    Patent document 2 describes a liquid ejecting device including a liquid ejecting head for ejecting liquid; a cleaning unit for cleaning the liquid ejecting head by ejecting liquid from the liquid ejecting head through a liquid path; and a detachably attached liquid storing unit for storing the liquid ejected by the cleaning unit, whereby the liquid storing unit is disposed on the outlet side of the liquid path. The liquid storing unit includes an absorbing unit for absorbing the liquid, and a forced dropping unit for forcibly dropping the liquid remaining in the liquid path to a liquid receiving position of the absorbing unit when the liquid storing unit is detached from the liquid ejecting device. 
         [0010]    Patent Document 1: Japanese Laid-Open Patent Application No. 2005-254636 
         [0011]    Patent Document 2: Japanese Laid-Open Patent Application No. 2007-130998 
         [0012]    However, in the apparatus described in patent document 1, the ink cannot be prevented from scattering while the image forming apparatus is operating. 
         [0013]    In the device described in patent document 2, the ink cannot be prevented from scattering while the image forming apparatus is operating, and moreover, when the maintenance unit is retrieved from the image forming apparatus, ink cannot be prevented from spilling out of the maintenance device. 
       SUMMARY OF THE INVENTION 
       [0014]    The present invention provides an image forming apparatus in which one or more of the above-described disadvantages are eliminated. 
         [0015]    A preferred embodiment of the present invention provides an image forming apparatus including a simple mechanism with which waste liquid is prevented from scattering out of a waste liquid jetting tube part of a maintenance device, and ink is prevented from spilling out of a maintenance device when the maintenance device is retrieved. 
         [0016]    According to an aspect of the present invention, there is provided an image forming apparatus including a recording head configured to jet liquid droplets of recording liquid; a maintenance device configured to maintain/restore a condition of the recording head, whereby the maintenance device is detachably attached to an apparatus main body of the image forming apparatus; and a waste liquid tank configured to hold waste liquid collected by the maintenance device, whereby the waste liquid tank is disposed adjacent to the maintenance device, wherein the maintenance device includes a waste liquid jetting tube configured to discharge the waste liquid into the waste liquid tank; the waste liquid tank includes an induction opening substantially surrounding the waste liquid jetting tube, whereby the induction opening includes a notch part through which the waste liquid jetting tube passes when the maintenance device is detached from the apparatus main body; and the image forming apparatus further includes a wall member configured to block at least part of the notch part when the maintenance device is attached in the apparatus main body. 
         [0017]    According to an aspect of the present invention, there is provided an image forming apparatus including a recording head configured to jet liquid droplets of recording liquid; a maintenance device configured to maintain/restore a condition of the recording head, whereby the maintenance device is detachably attached to an apparatus main body of the image forming apparatus; and a waste liquid tank configured to hold waste liquid collected by the maintenance device, whereby the waste liquid tank is disposed adjacent to the maintenance device, wherein the maintenance device includes a waste liquid jetting tube configured to discharge the waste liquid into the waste liquid tank; the waste liquid tank includes an induction opening substantially surrounding the waste liquid jetting tube; and at least part of the induction opening is formed with an elastic member configured to deform as the waste liquid jetting tube of the maintenance device contacts the elastic member, so that the waste liquid jetting tube can pass through the induction opening. 
         [0018]    According to one embodiment of the present invention, an image forming apparatus is provided, which includes a wall member that blocks at least part of a notch part of an induction opening of a waste liquid tank when a maintenance device is attached to the main body of the image forming apparatus, so that waste liquid scattered from a waste liquid jetting tube part of the maintenance device is blocked by the wall member of the induction opening, thereby preventing waste liquid from scattering with a simple mechanism. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings, in which: 
           [0020]      FIG. 1  is a schematic side view of an inkjet recording apparatus according to an embodiment of the present invention; 
           [0021]      FIG. 2  is a perspective view of a state where a maintenance device is detached from the main body of the image forming apparatus; 
           [0022]      FIGS. 3A and 3B  illustrate the maintenance device and a waste liquid tank, where  FIG. 3A  is a schematic front view of the maintenance device and the waste liquid tank, and  FIG. 3B  is a perspective view of a duct part of the waste liquid tank; 
           [0023]      FIGS. 4A through 4C  schematically illustrate a failure of the image forming apparatus; 
           [0024]      FIGS. 5A and 5B  illustrate a liquid droplet jetting device according to a first embodiment, where  FIG. 5A  schematically illustrates the state where the maintenance device is detached from the inkjet recording apparatus, and  FIG. 5B  schematically illustrates the state where the maintenance device is attached to the inkjet recording apparatus; 
           [0025]      FIG. 6  is a perspective view of the liquid droplet jetting device according to the first embodiment; 
           [0026]      FIGS. 7A and 7B  illustrate a liquid droplet jetting device according to a second embodiment, where  FIG. 7A  schematically illustrates the state where the maintenance device is detached from the inkjet recording apparatus, and  FIG. 7B  schematically illustrates the state where the maintenance device is attached to the inkjet recording apparatus; 
           [0027]      FIG. 8  schematically illustrates a liquid droplet jetting device according to a modification of the second embodiment; 
           [0028]      FIG. 9  schematically illustrates a liquid droplet jetting device according to another modification of the second embodiment; 
           [0029]      FIGS. 10A and 10B  illustrate a liquid droplet jetting device according to a third embodiment, where  FIG. 11A  schematically illustrates the state of the maintenance device detached from the inkjet recording apparatus, and  FIG. 10B  schematically illustrates the state of the maintenance device attached to the inkjet recording apparatus; and 
           [0030]      FIGS. 11A and 11B  illustrate a liquid droplet jetting device according to a fourth embodiment, where  FIG. 11A  schematically illustrates the state of the maintenance device set inside the inkjet recording apparatus, and  FIG. 11B  schematically illustrates the state of the maintenance device being attached into the inkjet recording apparatus. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]    A description is given, with reference to the accompanying drawings, of embodiments of the present invention. 
       Embodiments  
       [0032]    A description is given of an inkjet recording apparatus which is an image forming apparatus according to an embodiment of the present invention.  FIG. 1  is a schematic side view of an inkjet recording apparatus according to an embodiment of the present invention. An inkjet recording apparatus  100  includes a recording device engine  120  for forming images, whereby the recording device engine  120  is provided inside an apparatus main body  110 . A carriage  160  provided with recording heads  150  is provided in the recording device engine  120 . The recording heads  150  are moved in a main scanning direction along a rod  190 . 
         [0033]    The inkjet recording apparatus  100  includes a sheet feeding unit  130  where recording media P is placed, whereby the sheet feeding unit  130  is located at the bottom of the apparatus main body  110 . A recording medium that is fed out of the sheet feeding unit  130  is conveyed in a sub scanning direction by a belt  140  which is a sub scanning conveying unit. 
         [0034]    The recording medium is then moved in a main scanning direction by the belt  140  while ink is jetted from the recording heads  150  of the carriage  160  that is driven in a main scanning direction, so that an image is formed on the recording medium. 
         [0035]    The recording device engine  120  includes an ink cartridge  170 , an ink collecting container  180 , and a maintenance device  200 . When the ink cannot be normally jetted from the recording heads  150 , the maintenance device  200  performs a function recovery process on the recording heads  150  by suctioning the ink from the recording heads  150  through a auctioning cap  240  with the use of a pump  210 . The auctioned waste liquid is provided through a waste liquid jetting tube part  220  that extends down from the bottom of a main unit  270  of a maintenance device  200 , and into a waste liquid tank  300  having an induction opening  310 . The maintenance device  200  includes moisture caps  230  for preventing the recording heads  150  from drying, a wiper blade  250  for cleaning the jetting outlets of the recording heads  150 , and an ink collecting opening  260  for collecting the ink that has been removed by the wiper blade  250 . 
         [0036]    Next, a description is given of the location of the maintenance device  200  in the inkjet recording apparatus  100 .  FIG. 2  is a perspective view of a state where the maintenance device  200  is detached from the main unit of the image forming apparatus. The maintenance device  200  is for receiving ink that is suctioned from the recording heads  150 , and ink that is not used for printing but jetted for the purpose of maintaining the conditions of the recording heads  150  (idle jetting). This ink solidifies and deposits in the maintenance device  200 . Accordingly, the operating life of the maintenance device  200  is typically set to be shorter than that of the apparatus main body  110 . Thus, the maintenance device  200  is configured to be easily retrieved (detached) from the apparatus main body  110 . Specifically, the maintenance device  200  can be retrieved by sliding out the maintenance device  200  through an opening part  112  provided on a side surface part  111  of the apparatus main body  110 . 
         [0037]      FIGS. 3A and 3B  illustrate the maintenance device  200  and the waste liquid tank  300 .  FIG. 3A  is a schematic front view of the maintenance device  200  and the waste liquid tank  300 .  FIG. 3B  is a perspective view of a duct part of the waste liquid tank  300 . 
         [0038]    In the present embodiment, the maintenance device  200  is detachably attached to the apparatus main body  110  of the image forming apparatus, so that the maintenance device  200  can be retrieved by sliding it out. The waste liquid jetting tube part  220  extends down from the bottom of the maintenance device  200 . The waste liquid tank  300  is positioned beneath the maintenance device  200  of the apparatus main body  110 , and the induction opening  310  is positioned at the top part of the waste liquid tank  300  so as to surround the waste liquid jetting tube part  220 . The waste liquid from the waste liquid jetting tube part  220  of the maintenance device  200  is discharged through the induction opening  310  and transferred into the waste liquid tank  300 . The induction opening  310  has a peripheral wall part  320  substantially surrounding the waste liquid jetting tube part  220 . In the present embodiment, in one side of the peripheral wall part  320 , there is formed a notch part  330  through which the waste liquid jetting tube part  220  can pass when sliding the waste liquid jetting tube part  220  along a direction indicated by an arrow A (see  FIGS. 2 and 3B ) to retrieve the maintenance device  200  from the apparatus main body  110 . 
         [0039]    Merely forming the notch part  330  in the image forming apparatus may not be sufficient for preventing the following failure.  FIGS. 4A through 4C  schematically illustrate a failure of the image forming apparatus.  FIG. 4C  is a perspective magnified view of the circled part in  FIG. 4B . When there is no ink adhering to the end of the waste liquid jetting tube part  220 , as shown in  FIG. 4A , ink  280  that is discharged from the waste liquid jetting tube part  220  drops straight down and enters the waste liquid tank  300  through the induction opening  310 . However, when there is solid ink  290  adhering to the end of the waste liquid jetting tube part  220  ( FIG. 4C ), an end opening  221  of the waste liquid jetting tube part  220  is blocked by the solid ink  290 . Accordingly, the end opening  221  of the waste liquid jetting tube part  220  may become very small, and may be directed sideways. When the end opening  221  reaches the notch part  330  that is cut out in the peripheral wall part  320  shown in  FIGS. 3A and 3B , the ink  280  may scatter out from the notch part  330  and soil the inside of the image forming apparatus. 
         [0040]    Furthermore, the waste liquid may not be completely removed, and may still be remaining in the waste liquid jetting tube part  220  of the maintenance device  200 . Due to the impact when the maintenance device  200  is retrieved from the image forming apparatus in such a condition, the ink remaining in the waste liquid jetting tube part  220  may drop. Thus, the inside or the image forming apparatus or the floor on which the image forming apparatus is placed may be soiled. 
         [0041]    Accordingly, in the present embodiment, a wall member covering the notch part  330  of the waste liquid tank  300  is provided in the maintenance device  200 . The wall member may have various configurations. First, a description is given of a liquid droplet jetting device according to a first embodiment.  FIGS. 5A and 5B  illustrate a liquid droplet jetting device according to the first embodiment.  FIG. 5A  schematically illustrates the state where the maintenance device  200  is detached from the inkjet recording apparatus  100 ,  FIG. 5B  schematically illustrates the state where the maintenance device  200  is attached to the inkjet recording apparatus  100 , and  FIG. 6  is a perspective view of the liquid droplet jetting device according to the present embodiment. In the present embodiment, as shown in  FIG. 5A , a wall member  400  is provided in the maintenance device  200 . The wall member  400  has a plate  410  made of Mylar (registered trademark) extending down from the main unit  270  of the maintenance device  200 . In the present embodiment, when the maintenance device  200  is set into the apparatus main body  110  of the inkjet recording apparatus  100 , the plate  410  of the wall member  400  contacts the periphery of the notch part  330  formed in the peripheral wall part  320  of the waste liquid tank  300  so as to cover the notch part  330 , as shown in  FIG. 5B  and  FIG. 6 . Accordingly, in the liquid droplet jetting device according to the present embodiment, when the maintenance device  200  is attached to the inkjet recording apparatus  100 , the plate  410  covers the notch part  330  of the peripheral wall part  320 , so that waste liquid (ink) scattering from the waste liquid jetting tube part  220  is prevented from scattering outside from the waste liquid tank  300 . 
         [0042]    Next, a description is given of a modification of the liquid droplet jetting device according to a second embodiment.  FIGS. 7A and 7B  illustrate the liquid droplet jetting device according to the second embodiment.  FIG. 7A  schematically illustrates the state where the maintenance device  200  is detached from the inkjet recording apparatus  100 , and  FIG. 7B  schematically illustrates the state where the maintenance device  200  is attached to the inkjet recording apparatus  100 . In a wall member  500 , a plate  510  is provided in such a manner as to pivot on a shaft  520 . In between the plate  510  and the main unit  270  of the maintenance device  200 , an extension coil spring  530  is provided so that the plate  510  is urged against the main unit  270 . In such a configuration, when the maintenance device  200  is not attached to the apparatus main body  110 , as shown in  FIG. 7A , the plate  510  is positioned beneath the waste liquid jetting tube part  220  due to the extension coil spring  530 , so as to block waste liquid dropping from the waste liquid jetting tube part  220 . Meanwhile, when the maintenance device  200  is attached to the inkjet recording apparatus  100 , as shown in  FIG. 7B , the plate  510  contacts the induction opening  310  of the waste liquid tank  300  and pivots, so as to cover the notch part  330  of the peripheral wall part  320 . Accordingly, the waste liquid (ink) scattering from the waste liquid jetting tube part  220  is prevented from scattering out from the notch part  330 . 
         [0043]    According to the present embodiment, the maintenance device  200  is provided with the wall member  500 . Therefore, while the maintenance device  200  is attached to the inkjet recording apparatus  100 , it is possible to prevent soiling caused by the waste liquid scattering from the waste liquid jetting tube part  220 . Meanwhile, when the maintenance device  200  is detached from the inkjet recording apparatus  100 , the ink dropping from the moisture caps  230  of the maintenance device  200  can be blocked, so that the image forming apparatus is prevented from being soiled due to dropping ink. 
         [0044]    Next, a description is given of a modification of the second embodiment.  FIG. 8  schematically illustrates a liquid droplet jetting device according to the modification of the second embodiment. In the present embodiment, the main unit  270  of the maintenance device  200  is provided with a damper device  540  for absorbing the impact caused when the plate  510  contacts the main unit  270  of the maintenance device  200 . The damper device  540  is, for example, a rubber member, which is disposed on the bottom side of the main unit  270 . Specifically, the damper device  540  is located on the bottom side of the main unit  270 , where the plate  510  contacts the main unit  270  upon pivoting along a trajectory by being urged by the extension coil spring  530 . According to the present embodiment, when the maintenance device  200  is retrieved from the apparatus main body  110  of the inkjet recording apparatus  100 , the waste liquid adhering to the plate  510  is prevented from scattering around when the plate  510  impacts the maintenance device  200 . 
         [0045]    Next, a description is given of another modification of the second embodiment.  FIG. 9  schematically illustrates a liquid droplet jetting device according to the other modification of the second embodiment. In the present embodiment, the plate  510  and the shaft  520  of the wall member  500  are combined as a single unit, which is detachably attached to a hole part  271  formed in the main unit  270  of the maintenance device  200 . The main unit  270  of the maintenance device  200  is made of synthetic resin that is elastically deformable. The hole part  271  is made by forming an opening on the bottom side of the main unit  270 . 
         [0046]    Next, a description is given of a third embodiment.  FIGS. 10A and 10B  illustrate a liquid droplet jetting device according to the third embodiment.  FIG. 10A  schematically illustrates the state of the maintenance device  200  detached from the inkjet recording apparatus  100 , and  FIG. 10B  schematically illustrates the state of the maintenance device  200  attached to the inkjet recording apparatus  100 . In the present embodiment, a wall member  600  is provided in the waste liquid tank  300  disposed in the apparatus main body  110  of the inkjet recording apparatus  100 . 
         [0047]    In the wall member  600  according to the present embodiment, a plate  610  is rotatably provided on a shaft  620  that is disposed in the waste liquid tank  300 , and the plate  610  has a coil spring  630  and a contact plate  640 . The coil spring  630  urges the plate  610  in the direction toward the outside of the notch part  330 , and the contact plate  640  is fixed to the plate  610  such that a substantial right angle is formed between the contact plate  640  and the plate  610 . When the waste liquid jetting tube part  220  of the maintenance device  200  contacts the contact plate  640 , the plate  610  rotates to a position where it seals the notch part  330 . 
         [0048]    In the present embodiment, when the maintenance device  200  is attached to the apparatus main body  110  of the inkjet recording apparatus  100 , as shown in  FIG. 10B , the contact plate  640  is pressed by the pump  210 , so that the plate  610  rises and covers the notch part  330  of the peripheral wall part  320 . 
         [0049]    According to the present embodiment, the maintenance device  200  is provided with the wall member  600 . Therefore, while the maintenance device  200  is attached to the inkjet recording apparatus  100 , it is possible to prevent soiling caused by the waste liquid scattering from the waste liquid jetting tube part  220 . 
         [0050]    Next, a description is given of a fourth embodiment.  FIGS. 11A and 11B  illustrate a liquid droplet jetting device according to the fourth embodiment.  FIG. 11A  schematically illustrates the state of the maintenance device  200  set inside the inkjet recording apparatus  100 , and  FIG. 11B  schematically illustrates the state of the maintenance device  200  being attached into the inkjet recording apparatus  100 . 
         [0051]    In the present embodiment, at a position corresponding to the notch part  330 , the peripheral wall part  320  of the waste liquid tank  300  is provided with an elastic rubber plate member  710 , in such a manner as to cover the notch part  330 . In the present embodiment, when the maintenance device  200  is attached into the inkjet recording apparatus  100 , as shown in  FIG. 11B , the waste liquid jetting tube part  220  of the maintenance device  200  contacts the plate member  710 , so that the plate member  710  elastically deforms. Accordingly, the maintenance device  200  can be easily attached in the inkjet recording apparatus  100 . When the maintenance device  200  is set inside the inkjet recording apparatus  100 , as shown in  FIG. 11A , the plate member  710  returns to its original shape, so that the waste liquid scattering from the waste liquid jetting tube part  220  is prevented from scattering outside of the peripheral wall part  320 . 
         [0052]    Furthermore, when the maintenance device  200  is retrieved from the apparatus main body  110 , the plate member  710  deforms in the direction opposite to that when the maintenance device  200  is attached, so that the maintenance device  200  can be easily retrieved from the inkjet recording apparatus  100 . 
         [0053]    Thus, according to the present embodiment, with a simple structure of providing a plate member to the waste liquid tank, the maintenance device can be easily attached/detached, and soiling caused by scattering waste liquid can be prevented. 
         [0054]    The present invention is not limited to the specifically disclosed embodiment, and variations and modifications may be made without departing from the scope of the present invention. 
         [0055]    The present application is based on Japanese Priority Patent Application No. 2008-193088, filed on Jul. 28, 2008, the entire contents of which are hereby incorporated herein by reference.