Patent Publication Number: US-9904212-B2

Title: Toner agitation system including a cam driven reciprocating toner agitator

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application Ser. No. 62/218,610, filed Sep. 15, 2015, entitled “Reciprocating Toner Agitator Drive,” the content of which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     1. Field of the Disclosure 
     The present invention relates generally to electrophotographic image forming devices and more particularly to a cam driven reciprocating toner agitator. 
     2. Description of the Related Art 
     During the electrophotographic printing process, an electrically charged rotating photoconductive drum is selectively exposed to a laser beam. The areas of the photoconductive drum exposed to the laser beam are discharged creating an electrostatic latent image of a page to be printed on the photoconductive drum. Toner particles are then electrostatically picked up by the latent image on the photoconductive drum creating a toned image on the photoconductive drum. The toned image is transferred to the print media (e.g., paper) either directly by the photoconductive drum in a one-step transfer system or indirectly by an intermediate transfer member in a two-step transfer system. The toner is then fused to the media using heat and pressure to complete the print. Not all of the toner picked up by the photoconductive drum is transferred to the print media or intermediate transfer member due to inefficiencies in the image transfer process. Residual toner left on the photoconductive drum after the photoconductive drum has contacted the print media or intermediate transfer member is removed before the next image is formed in order to avoid contamination of the next image. For this purpose, a cleaner blade or a cleaner brush in contact with the photoconductive drum (and, in a two-step transfer system, the intermediate transfer member) removes the residual toner from its surface. 
     The residual toner removed by the cleaner blade or cleaner brush is typically stored in a reservoir of a waste toner container that is replaced periodically when it fills with toner in order to accommodate additional waste toner. Similarly, the image forming device&#39;s toner supply is typically stored in reservoirs of one or more units that are replaced periodically in order to continue to provide toner to the image forming device for printing. The reservoirs that store fresh toner and waste toner include agitators that fluff and mix the toner in the reservoir to prevent it from clumping and to distribute the toner more evenly throughout the reservoir. 
     SUMMARY 
     A toner agitation system according to one example embodiment includes a toner agitator movable in a reciprocating manner. A cam follower is operatively connected to the toner agitator. A rotatable cam has a cam surface that contacts the cam follower. A biasing member biases the cam follower into contact with the cam surface. Contact between the cam surface and the cam follower during rotation of the cam causes the toner agitator to move in the reciprocating manner. 
     A toner container according to one example embodiment includes a housing having a reservoir for storing toner. A toner agitator is movable in a reciprocating manner within the reservoir. A cam follower is operatively connected to the toner agitator. A rotatable cam has a cam surface that contacts the cam follower. A biasing member biases the cam follower into contact with the cam surface. Contact between the cam surface and the cam follower during rotation of the cam causes the toner agitator to move in the reciprocating manner. 
     A container for storing waste toner in an electrophotographic image forming device according to one example embodiment includes a housing having a reservoir for storing toner. At least one toner inlet permits toner to enter the reservoir. A toner agitator is movable in a reciprocating manner within the reservoir. The toner agitator includes a cam follower. A rotatable cam has a cam surface that contacts the cam follower. A biasing member biases the cam follower into constant contact with the cam surface throughout an entire rotational path of the cam. Contact between the cam surface and the cam follower during rotation of the cam causes the toner agitator to move back and forth in the reciprocating manner against a direction of bias of the biasing member on the cam follower and in the direction of bias of the biasing member on the cam follower. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings incorporated in and forming a part of the specification, illustrate several aspects of the present disclosure, and together with the description serve to explain the principles of the present disclosure. 
         FIG. 1  is a schematic view of an image forming device according to one example embodiment. 
         FIG. 2  is a perspective view of an interior of a waste toner container showing a toner agitator according to one example embodiment. 
         FIGS. 3A-3D  are sequential elevation views of a cam drive of the toner agitator according to one example embodiment. 
         FIG. 4  is a perspective view of an exterior of the waster toner container showing a drive coupler that receives rotational motion to drive the toner agitator according to one example embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, reference is made to the accompanying drawings where like numerals represent like elements. The embodiments are described in sufficient detail to enable those skilled in the art to practice the present disclosure. It is to be understood that other embodiments may be utilized and that process, electrical, and mechanical changes, etc., may be made without departing from the scope of the present disclosure. Examples merely typify possible variations. Portions and features of some embodiments may be included in or substituted for those of others. The following description, therefore, is not to be taken in a limiting sense and the scope of the present disclosure is defined only by the appended claims and their equivalents. 
       FIG. 1  illustrates a schematic view of the interior of an example image forming device  20 . Image forming device  20  includes a housing  22  having a top  24 , bottom  25 , front  26  and rear  27 . Housing  22  includes one or more input trays  28  positioned therein. Trays  28  are sized to contain a stack of media sheets. As used herein, the term media is meant to encompass not only paper but also labels, envelopes, fabrics, photographic paper or any other desired substrate. Trays  28  are preferably removable for refilling. A control panel (not shown) may be located on housing  22 . Using the control panel, a user is able to enter commands and generally control the operation of the image forming device  20 . For example, the user may enter commands to switch modes (e.g., color mode, monochrome mode), view the number of pages printed, etc. A media path  32  extends through image forming device  20  for moving the media sheets through the image transfer process. Media path  32  includes a simplex path  34  and may include a duplex path  36 . A media sheet is introduced into simplex path  34  from tray  28  by a pick mechanism  38 . In the example embodiment shown, pick mechanism  38  includes a roll  40  positioned at the end of a pivotable arm  42 . Roll  40  rotates to move the media sheet from tray  28  and into media path  32 . The media sheet is then moved along media path  32  by various transport rolls. Media sheets may also be introduced into media path  32  by a manual feed  46  having one or more rolls  48 . 
     Image forming device  20  includes an image transfer section that includes one or more imaging stations  50 . In the example embodiment illustrated, each imaging station  50  includes a toner cartridge  100 , a developer unit  110  and a photoconductor unit  120 . Each toner cartridge  100  includes a reservoir  102  for holding toner and an outlet port in communication with an inlet port of a corresponding developer unit  110  for periodically transferring toner from reservoir  102  to developer unit  110  in order to replenish the developer unit  110 . In the example embodiment illustrated, image forming device  20  utilizes what is commonly referred to as a single component development system. In this embodiment, each developer unit  110  includes a toner reservoir  112  and a toner adder roll  114  that moves toner from reservoir  112  to a developer roll  116 . One or more agitating members may be positioned within each of reservoir  102  and reservoir  112  to aid in moving the toner. Each photoconductor unit  120  includes a photoconductive (PC) drum  122 , a charge roll  124  and a cleaner blade or roll  126 . PC drums  122  are mounted substantially parallel to each other. For purposes of clarity, developer unit  110  and photoconductor unit  120  are labeled on only one of the imaging stations  50 . Each imaging station  50  may be substantially the same except for the color of toner used. 
     Each charge roll  124  forms a nip with the corresponding PC drum  122 . During a print operation, charge roll  124  charges the surface of PC drum  122  to a specified voltage, such as, for example, −1000 volts. A laser beam from a printhead  52  associated with each imaging station  50  is then directed to the surface of PC drum  122  and selectively discharges those areas it contacts to form a latent image on the surface of PC drum  122 . In one embodiment, areas on PC drum  122  illuminated by the laser beam are discharged to approximately −300 volts. Developer roll  116 , which forms a nip with the corresponding PC drum  122 , then transfers toner to the latent image on the surface of PC drum  122  to form a toner image. The toner is attracted to the areas of PC drum  122  surface discharged by the laser beam from the printhead  52 . A metering device, such as a doctor blade, can be used to meter toner onto developer roll  116  and apply a desired charge on the toner prior to its transfer to PC drum  122 . 
     An intermediate transfer mechanism (ITM)  54  is disposed adjacent to the imaging stations  50 . In this embodiment, ITM  54  is formed as an endless belt trained about a drive roll  56 , a tension roll  58  and a back-up roll  60 . During image forming operations, ITM  54  moves past imaging stations  50  in a clockwise direction as viewed in  FIG. 1 . One or more of PC drums  122  apply toner images in their respective colors to ITM  54  at a first transfer nip  62 . In one embodiment, a positive voltage field attracts the toner image from PC drums  122  to the surface of the moving ITM  54 . ITM  54  rotates and collects the one or more toner images from imaging stations  50  and then conveys the toner images to a media sheet at a second transfer nip  64  formed between a transfer roll  66  and ITM  54 , which is supported by back-up roll  60 . The cleaner roll  126  of each photoconductor unit  120  removes any toner remnants on PC drum  122  so that the surface of PC drum  122  may be charged and developed with toner again. 
     A media sheet advancing through simplex path  34  receives the toner image from ITM  54  as it moves through the second transfer nip  64 . The media sheet with the toner image is then moved along the media path  32  and into a fuser area  68 . Fuser area  68  includes fusing rolls or belts  70  that form a nip  72  to adhere the toner image to the media sheet. The fused media sheet then passes through exit rolls  74  that are located downstream from the fuser area  68 . Exit rolls  74  may be rotated in either forward or reverse directions. In a forward direction, exit rolls  74  move the media sheet from simplex path  34  to an output area  76  on top  24  of image forming device  20 . In a reverse direction, exit rolls  74  move the media sheet into duplex path  36  for image formation on a second side of the media sheet. A cleaner roll  128  removes any toner remnants on ITM  54  so that the surface of ITM  54  may receive toner from PC drums  122  again. 
     While the example image forming device  20  shown in  FIG. 1  illustrates four toner cartridges  100  and four corresponding developer units  110  and photoconductor units  120 , it will be appreciated that a monocolor image forming device  20  may include a single toner cartridge  100  and corresponding developer unit  110  and photoconductor unit  120  as compared to a multicolor image forming device  20  that may include multiple toner cartridges  100 , developer units  110  and photoconductor units  120 . Further, although image forming device  20  utilizes ITM  54  to transfer toner to the media, toner may be applied directly to the media by the one or more PC drums  122  as is known in the art. 
     While the example image forming device  20  shown in  FIG. 1  utilizes a single component development system, in another embodiment, image forming device  20  utilizes what is commonly referred to as a dual component development system. In this embodiment, reservoir  112  of developer unit  110  stores a mixture of toner and magnetic carrier beads. The carrier beads may be coated with a polymeric film to provide triboelectric properties to attract toner to the carrier beads as the toner and the carrier beads are mixed in reservoir  112 . Each developer unit  110  also includes a magnetic roll that attracts the carrier beads in reservoir  112  having toner thereon to the magnetic roll through the use of magnetic fields and transports the toner to the corresponding PC drum  122 . Electrostatic forces from the latent image on PC drum  122  strip the toner from the carrier beads to form a toner image on the surface of PC drum  122 . PC drum  122  is charged by charge roll  124  and cleaned by cleaner roll  126  as discussed above. 
       FIG. 2  illustrates a reservoir  202  of a waste toner container  200  of image forming device  20  according to one example embodiment. Reservoir  202  is contained within a housing  204  of waste toner container  200 . Reservoir  202  stores waste toner that fails to transfer from and is then cleaned from PC drum(s)  122  or ITM  54  by cleaner rolls  126  or  128 . Waste toner container  200  may be removable from image forming device  20  as desired in order to permit replacement or emptying of waste toner container  200  when it fills with toner in order to accommodate additional waste toner. As shown in  FIG. 2 , housing  204  includes one or more toner inlets  206  through which waste toner enters reservoir  202 . Toner cleaned from PC drum(s)  122  and ITM  54  is fed to inlets  206  by toner conveyors, e.g., augers, paddles or the like. In the embodiment illustrated, each inlet  206  includes a shutter  208  that is movable between an open position that permits toner to enter reservoir  202  through inlets  206  and a closed position that prevents toner from leaking out of housing  204  when waste toner container  200  is removed from image forming device  20 . 
     A toner agitator  210  is positioned within reservoir  202  to mix and break up any clumped toner in reservoir  202  in order to more evenly distribute the toner in reservoir  202  so that volumetric capacity of reservoir  202  is used more efficiently. Agitator  210  is movable in a reciprocating back and forth manner along a lengthwise direction thereof indicated by arrow A in  FIG. 2 . For example, in the embodiment illustrated, agitator  210  is translatable linearly in a reciprocating manner left and right as viewed in  FIG. 2 . In the example embodiment illustrated, agitator  210  includes a series of rake teeth  214  that extend outward from a spine  212  of agitator  210 . Spine  212  extends along a lengthwise direction of agitator  210  and, in the embodiment illustrated, rake teeth  214  extend perpendicular to the lengthwise direction of agitator  210 . However, rake teeth  214  may extend at any suitable angle or direction to the lengthwise direction of agitator  210 . Further, agitator  210  may take many suitable forms other than the embodiment illustrated. For example, agitator  210  may include any desired form of paddle, scraper, conveyor, coil, etc. 
     Agitator  210  is driven by a rotatable cam  220 . Cam  220  is rotated (e.g., counterclockwise as viewed in  FIG. 2 ) by a drive shaft  222  that defines a rotational axis  224  of cam  220 . Cam  220  includes an eccentric or irregular disc  226  or other shape that defines a cam surface  228  of cam  220 . For example, in the embodiment illustrated, cam  220  includes a circular disc  226  that has a center  227  that is offset from rotational axis  224  of drive shaft  222 . Agitator  210  includes an engagement surface  216  that is positioned to contact cam surface  228  and serve as a cam follower as cam  220  rotates. In the embodiment illustrated, engagement surface  216  is formed integrally with agitator  210  on a wall  218  that protrudes outward from spine  212  of toner agitator  210 . In other embodiments, engagement surface  216  may be formed on a separate component connected to toner agitator  210 . 
     A biasing member  230  biases engagement surface  216  of agitator  210  into contact with cam surface  228  such that engagement surface  216  remains in contact with cam surface  228  through the entire rotational path of disc  226 . In the embodiment illustrated, biasing member  230  includes an extension spring that pulls engagement surface  216  of agitator  210  into contact with cam surface  228 ; however, any suitable biasing member may be used (e.g., a compression spring that pushes engagement surface  216  of agitator  210  into contact with cam surface  228 , a leaf spring, a torsion spring or another member composed of a material having resilient properties). 
       FIGS. 3A-3D  illustrate sequential views of the motion of cam  220  and agitator  210  as drive shaft  222  rotates. As drive shaft  222  rotates counterclockwise as viewed in  FIGS. 3A-3D , cam  220  rotates counterclockwise therewith. As cam  220  rotates counterclockwise from the position shown in  FIG. 3A , through the position shown in  FIG. 3B  and toward the position shown in  FIG. 3C , contact between cam surface  228  and engagement surface  216  of agitator  210  causes agitator  210  to move to the left as viewed in  FIGS. 3A-3D  against the bias applied to agitator  210  by biasing member  230  as center  227  of disc  226  moves to the left as shown in  FIGS. 3A and 3B .  FIG. 3C  illustrates agitator  210  at one end of its travel (a leftmost end of travel as viewed in  FIGS. 3A-3D ). As cam  220  continues to rotate counterclockwise from the position shown in  FIG. 3C , through the position shown in  FIG. 3D  and back toward the position shown in  FIG. 3A , the bias applied to agitator  210  causes agitator  210  to move to the right as viewed in  FIGS. 3A-3D  in the direction of bias applied to agitator  210  by biasing member  230  with engagement surface  216  of agitator  210  remaining in contact with cam surface  228  as center  227  of disc  226  moves back to the right as shown in  FIGS. 3C and 3D .  FIG. 3A  illustrates agitator  210  at the other end of its travel (a rightmost end of travel as viewed in  FIGS. 3A-3D ). 
     In the embodiment illustrated, engagement surface  216  of agitator  210  and cam surface  228  remain in constant contact through the entire rotational path of drive shaft  222  and cam  220 . The constant contact between engagement surface  216  of agitator  210  and cam surface  228  reduces the noise generated by agitator  210  as agitator  210  moves back and forth within reservoir  202 . Specifically, by maintaining contact between engagement surface  216  of agitator  210  and cam surface  228 , noise that would otherwise be generated by the repeated engagement and disengagement of agitator  210  and its drive member is avoided. Further, in the embodiment illustrated, the constant contact between engagement surface  216  of agitator  210  and cam surface  228  allows agitator  210  to reciprocate freely back and forth without the use of motion limiting stops thereby avoiding the noise that would otherwise be generated by agitator  210  contacting a stop at the end of its travel in each direction. 
       FIG. 4  illustrates the exterior of housing  204  of waste toner container  200  according to one example embodiment. Housing  204  includes a drive coupler  232  exposed on the exterior thereof and operatively connected (directly or indirectly) to drive shaft  222 . When waste toner container  200  is installed in image forming device  20 , drive coupler  232  mates with a corresponding drive member that provides rotational motion to drive coupler  232  from a motor in image forming device  20 . Drive coupler  232  may be any suitable gear or coupling for receiving rotational motion. 
     While the example embodiment illustrated includes a cam driven agitator positioned in the reservoir of a waste toner container, it will be appreciated that such a cam arrangement may be used to drive a reciprocating agitator in any toner reservoir, such as, for example, reservoir  102  of toner cartridge  100  or reservoir  112  of developer unit  110 . 
     The foregoing description illustrates various aspects of the present disclosure. It is not intended to be exhaustive. Rather, it is chosen to illustrate the principles of the present disclosure and its practical application to enable one of ordinary skill in the art to utilize the present disclosure, including its various modifications that naturally follow. All modifications and variations are contemplated within the scope of the present disclosure as determined by the appended claims. Relatively apparent modifications include combining one or more features of various embodiments with features of other embodiments.