Patent Publication Number: US-7912400-B2

Title: Devices and methods for removing toner from a belt within an image forming apparatus

Description:
BACKGROUND 
     The present application is directed to devices and methods for removing toner from a belt within an image forming apparatus. 
     Image forming apparatuses form and transfer one or more toner images to a media sheet. In a direct transfer system, the toner images are initially formed on a development member and then transferred to a media sheet. In a secondary transfer system, the toner images initially formed on the development member are first transferred to an intermediate member, and then transferred from the intermediate member to the media sheet. The toner images may be transferred to a belt in the various transfer systems. The belt may include but is not limited to a transfer belt that moves the media sheet in the direct transfer system, the intermediate member in the secondary transfer system, and the development member in either system. 
     Some portion of the one or more of the toner images may not transfer from the belt during the transfer process. This non-transferred toner, referred to as residual toner, should be removed from the belt prior to the next toner image being transferred to the belt. In some prior art devices, a cleaner device is positioned to remove the residual toner from the belt. However, these prior art devices have caused various types of problems. 
     Many prior art toner removal devices are relatively large. With the size of many image forming apparatuses currently being reduced, the space available for positioning the removal devices is often small. Many current apparatuses include architectures that cannot accommodate a large removal device. 
     The physical properties of the toner may further complicate removal of the residual toner from the belt. The toner may tend to adhere together forming a mass that is difficult to move away from the belt. The adhered toner also prevents subsequent residual toner from being removed from the belt. 
     SUMMARY 
     The present application is directed to devices and methods for removing toner from a belt within an image forming apparatus. In one embodiment, the device includes a housing that forms an enclosed interior space. The housing may include an inlet that leads into the interior space. A blade may be positioned in proximity to the inlet to remove the toner from the belt and direct it into the inlet. An auger may be rotationally positioned within the interior space to move the toner along a longitudinal width of the device. An agitating member may be rotationally positioned within the interior space to move the toner along a depth of the device from the inlet towards the auger. In one embodiment, the agitating member includes a flexible arm that contacts against at least one of the blade and the auger during rotation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic side view of an image forming apparatus according to one embodiment. 
         FIG. 2  is a perspective view of a removal device according to one embodiment. 
         FIG. 3  is a schematic section view of a removal device according to one embodiment. 
         FIG. 4  is a perspective view of an auger with a gear mounted at an end according to one embodiment. 
         FIG. 5  is a perspective view of an agitating member according to one embodiment. 
         FIG. 6  is a schematic side view of a cleaning device according to one embodiment. 
         FIG. 7  is a side schematic view of a gear train according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The present application is directed to a toner removal device and methods for removing residual toner from a belt within an image forming apparatus. The device may include a housing that forms an enclosed interior space. A blade may be positioned to remove the toner from the belt and direct it into the interior space. An auger may be rotationally positioned within the interior space to move the toner along a longitudinal length of the device. An agitating member may be rotationally positioned within the interior space to move the toner towards the auger. The agitating member may include a flexible arm that contacts against at least one of the blade and the auger during rotation. 
       FIG. 1  depicts a representative image forming apparatus, indicated generally by the numeral  100 . The image forming apparatus  100  includes a printer body  112  with an interior space sized to hold a main media sheet stack  116 . Media sheets may also be introduced through a manual input  120 . The term “image forming apparatus” and the like is used generally herein as a device that produces images on a media sheet. Examples include but are not limited to a laser printer, ink-jet printer, fax machine, copier, and a multi-functional machine. Examples of an image forming apparatus include Model Nos. C750 and C752 available from Lexmark International, Inc. of Lexington, Ky. 
     A number of image formation cartridges  126  are positioned within the body  112 . In one embodiment, each cartridge  126  may be removed from the body  112  and replaced as necessary. The cartridges  126  may each include a similar construction but are distinguished by the toner color contained therein. In one embodiment, the image forming apparatus  100  includes a black cartridge (K), a magenta cartridge (M), a cyan cartridge (C), and a yellow cartridge (Y). Each cartridge  126  forms an individual monocolor toner image that is combined in layered fashion with toner images from the other cartridges to create the final multi-colored toner image. The image forming apparatus  100  further includes an intermediate transfer mechanism (ITM) belt  124 , one or more imaging devices  130 , a fuser  132 , and a removal device  10  as well as various rollers, actuators, sensors, optics, and electronics (not shown) as are conventionally known in the image forming apparatus arts, and which are not further explicated herein. 
     The internal components of removable image formation cartridges  126  are not specifically identified in  FIG. 1 , but are briefly described. Each image formation cartridge  126  is a removable cartridge that may include a reservoir holding a supply of toner, a developer roller for applying toner to develop a latent image on a photoconductive drum, and a photoconductive (PC) drum  114 , which may comprise, for example, an aluminum hollow-core drum coated with one or more layers of light-sensitive organic photoconductive materials. The image formation cartridge  126  may additionally include various rollers, paddles, augers and blades, as well known in the art. Note that this description is representative only—various image formation devices may organize these components into a plurality of cartridges. 
     The operation of the image forming apparatus  100  is conventionally known. Upon command from control electronics, a single media sheet is “picked,” or selected, from either the main media sheet stack  116  or the manual input  120 . Regardless of its source, the media sheet is transported to a second transfer location  122  to receive a toner image from the ITM belt  124 . The ITM belt  124  is endless and rotates in the direction indicated by arrow R around a series of rollers adjacent to the PC drums  114  of the respective image formation cartridges  126 . Rolls include a drive roll  141 , a backup roll  142 , a reverse roll  143 , and a tension roll  144 . A motor  167  is operatively connected to provide rotational power to the drive roll  141 . Toner is deposited from each PC drum  114  as needed to create a full color image on the ITM belt  124 . The ITM belt  124  and each PC drum  114  are synchronized so that the toner from each PC drum  114  precisely aligns on the ITM belt  124  during a single pass. 
     The media sheet may receive an electrostatic charge before contacting the ITM belt  124  at the second transfer location  122  to assist in attracting the toner from the ITM belt  124 . The transfer location  122  includes a nip formed between the backup roll  142  and a second transfer roll  129 . The sheet and attached toner next travel through a fuser  132  having a pair of rollers and a heating element that heats and fuses the toner to the sheet. The sheet with fused image is then transported out of the printer body  112  for retrieval by a user. Alternatively, the media sheet is moved through a duplex path  139  for image formation on a second side. 
     The removal device  10  removes the toner that remains on ITM belt  124  after the second transfer location  122 . This residual toner should be removed prior to the belt  124  rotating around and receiving new toner images from the PC drums  114  for subsequent image formations. 
       FIG. 2  illustrates a perspective view of the removal device  10 . Device  10  includes a housing  20  with a front side  21  that faces towards the ITM belt  124 . Front side  21  includes a blade  23  positioned to remove the toner from the ITM belt  124 . The device  10  includes a depth D measured between the front side  21  and a back side  28 , a height H measured between a floor  27  and a ceiling  29 , and a width W measured between first and second ends  87 ,  88 . 
     An inlet  22  is formed adjacent to the blade  23  to receive the toner and direct it into an interior space  25  formed within the housing  20 . A seal  24  is positioned below the inlet  22  to prevent the residual toner from escaping from the inlet  22  and interior space  25 . In one embodiment, the width of the removal device  10  is substantially equal to a width of the ITM belt  124 . 
       FIG. 3  illustrates a section view of the housing  20  and the elements within the interior space  25 . The front side  21  includes the blade  23  that extends outward to remove the toner from the ITM belt  124 . The blade  23  includes a first side that faces outward towards the ITM belt  124 , and a second side that faces inward towards the interior space  25 . Blade  23  may further include a leading edge that forms an upper extent of the inlet  22 . Blade  23  may further be mounted on a bracket  26  that is connected to the housing  20 . 
     The inlet  22  is formed directly below the blade  23  to receive the toner as it is removed from the ITM belt  124 . The lower extent of the inlet  22  is formed by the seal  24  that extends upward from a bottom of the housing  20 . The height of the inlet  22  measured between the blade  23  and seal  24  may vary, with one embodiment including a height of about 5 mm. 
     The interior space  25  receives the toner through the inlet  22 . The interior space  25  includes the floor  27  that extends between the inlet  22  and an auger  50 . The interior space  25  may further include the ceiling  29  spaced vertically upward from the floor  27 . 
     The auger  50  is positioned in the interior space  25  in proximity to the floor  27  and away from the inlet  22 .  FIG. 4  illustrates one embodiment of the auger  50  that includes a number of helical coils  51 . The auger  50  includes an elongated shape and extends along the longitudinal width of the housing  20 . Auger  50  may extend the entire length or a limited length of the housing  20 . Auger  50  moves the toner longitudinally along the width in the direction indicated by arrow T to a separate part of the housing  20  or a remote storage container  150 . In the embodiments shown in the Figures, the auger  50  is depicted as a coiled wire, although other conveyors known to those skilled in the art, including screws or other equivalent devices, may be used. A gear  72  may be attached to an end of the auger  50 . Gear  72  may include a shaft  53  with a rotational center point  52 . 
     As illustrated in  FIGS. 3 and 5 , an agitating member  40  is positioned within the interior space  25  between the blade  23  and the auger  50 . The agitating member  40  rotates within the interior space  25  and moves the toner away from the inlet  22  and towards the auger  50 . In the embodiment of  FIG. 3 , the agitating member  40  rotates in direction P. Agitating member  40  includes an elongated shaft  41  that may include a variety of lengths, and may include various sectional shapes including rectangular as illustrated in  FIG. 3  and circular as illustrated in  FIG. 5 . An arm  42  is attached to and extends outward from the shaft  41 . Arm  42  may include the same or a different length as the shaft  41 . As illustrated in  FIG. 5 , a distance X is formed between a center C of the shaft  41  and an outer end  43  of the arm  42 . Arm  42  may be constructed from various materials. In one embodiment, arm  42  is constructed of a flexible material that deforms during rotation of the agitating member  40 . Materials include but are not limited to mylar, plastic, and rubber. In one specific embodiment, arm  42  is mylar that is about 0.125 millimeter thick. 
     As illustrated in  FIG. 3 , the auger  50  is positioned within the sweep envelope of the agitating member  40  as a distance between the center C of the shaft  41  and the edge of the auger  50  is less than X. This positioning causes the arm  42  to contact against the auger  50  and deform as it rotates past the auger  50 . The deformation causes the arm  42  to direct the toner into the auger  50  where it is then moved laterally and out of the housing  20 . Likewise, the blade  23  may be positioned within the sweep envelope of the agitating member  40  causing the arm  42  to contact against the blade  23  and deform as it rotates. This deformation prevents toner from pooling within the inlet  22  and maintains the toner moving towards the auger  50 . The agitating member  40  may also be positioned for the arm  42  to contact the floor  27  and/or ceiling  29  during rotation. 
     In another embodiment, the agitating member  40  is positioned such that it contacts just one of the blade  23  and the auger  50  during the rotation. Stated in another manner, only one of the blade  23  and auger  50  lie within the sweep envelope of the agitating member  40 . 
       FIG. 6  illustrates a schematic representation of the removal device  10  according to one embodiment. The removal device includes a depth D that extends between the front side  21  and the back side  28  of the housing  20 . Device  10  also includes a height H that extends between the floor  27  and the ceiling  29 . In one embodiment, the device  10  is positioned in a horizontal orientation with the inlet  22  at the same height H as the auger  50  (i.e., the inlet  22  is at the same height as the sweep envelope of the auger  50 ). Further, the floor  27  may be substantially horizontal and lie at the same height along the depth of the housing  20 . Because of the horizontal orientation and the inlet  22  and the auger  50  at the same height H, the agitating member  40  is necessary to move the toner from the inlet  22  towards the auger  50  as gravity is not a factor to move the toner. The horizontal, orientation may be a result of the device  10  positioned within the image forming apparatus  100  at a point along a vertical section of the ITM belt  124 . 
     In another embodiment as illustrated in  FIG. 6 , the shaft  41  of the agitating member  40  is positioned at a greater height H than the inlet  22 . The shaft  41  may also be positioned at a greater height H than the sweep envelope of the auger  50  as illustrated in the embodiment of  FIG. 6 , or within the sweep envelope but above a center point  52  of the auger  50  as illustrated in  FIG. 3 . 
     As illustrated in  FIG. 2 , removal device  10  may further include a number of gears on the exterior of the housing  20 . In this embodiment, the gears include an agitating member gear  71  connected to the shaft  41  of the agitating member  40 . An auger gear  72  is connected to the auger  50 . An idler gear  73  may operatively connect the gears  71 ,  72 . The gears transfer a rotational force to rotate the auger  50  and agitating member  40 . In one embodiment, the size of the auger gear  72  is smaller than the agitating member gear  71  causing the auger  50  to rotate at a greater speed than the agitating member  40 . 
       FIG. 7  illustrates a gear train  70  that provides the rotational force to the agitating member  40  and the auger  50 . An idler gear  75  is operatively connected to the motor  167  that rotates the drive roll  141  of the ITM belt  124 . Idler gear  75  meshes with a second auger gear  74  that is also positioned on the auger shaft  53 . Rotation of second auger gear  74  imparts rotation to the auger shaft  53  which drives gears  72 ,  73 , and  71 . 
     The position of the agitating member  40  within the interior space  25  may vary. In one embodiment as illustrated in  FIG. 3 , the auger  50  and the blade  23  are each positioned within the sweep envelope of the agitating member  40 . In another embodiment, only one of the auger  50  and blade  23  are positioned within the sweep envelope. In another embodiment, neither of the auger  50  or blade  23  are positioned within the sweep envelope. In this embodiment, the arm  42  does not contact either of the auger  50  or blade  23  during rotation. The arm  42  in this embodiment may be constructed out of a flexible material. Alternatively, arm  42  may be constructed from a non-flexible material, including but not limited to Mylar, PET, TPE, ETFE, PI, PAI, and other film materials. 
     The agitating member  40  may include a single arm  42  as illustrated in the embodiment of  FIG. 5 . In another embodiment, the agitating member  40  includes multiple arms. Each of the arms may include the same shape and length, or may include different shapes and/or lengths. Further, the arm  42  may include a variety of different shapes and sizes. In one embodiment, an opening is positioned within the arm  42  between the shaft  41  and the outer end  43 . 
     In the embodiment illustrated in  FIG. 1 , the removal device  10  removes toner from an ITM belt  124 . Removal device  10  may also remove toner from other belts. In another embodiment, removal device  10  removes toner from a transport belt used to transport media sheets in a direct transfer apparatus. The toner may be applied to the transport belt for various reasons, such as during color calibration processes, or inadvertently during transport of the media sheets and toner. In another embodiment, the PC drums  114  are formed as belts and the removal device  10  is positioned to remove toner from the surfaces of these belts. 
     Spatially relative terms such as “under”, “below”, “lower”, “over”, “upper”, and the like, are used for ease of description to explain the positioning of one element relative to a second element. These terms are intended to encompass different orientations of the device in addition to different orientations than those depicted in the figures. Further, terms such as “first”, “second”, and the like, are also used to describe various elements, regions, sections and the like and are also not intended to be limiting. Like terms refer to like elements throughout the description. 
     As used herein, the terms “having”, “containing”, “including”, “comprising” and the like are open ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise. 
     The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. In one embodiment, the auger  50 , agitating member  40 , and the blade  23  extend along an entire longitudinal width of the housing  20 . The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.