Abstract:
An image forming device having a main body and a movable subunit. The subunit is movable between a first orientation and a second orientation. A developer member is positioned within the main body, and a photoconductive member is positioned on the subunit. In the first orientation, the developer member and photoconductive member are spaced apart. In the second orientation, the photoconductive member is positioned either in contact with or closely located to the developer member. Image formation occurs when the subunit is in the second orientation as toner is transferred from the developer member to the photoconductive member. Methods of using the image forming device include positioning the developer member in the main body and the photoconductive member on the subunit, and moving the subunit from a first orientation to a second orientation such that image formation can occur.

Description:
BACKGROUND 
   Image forming devices require user intervention for proper operation. One user intervention is clearing the media path during a paper jam. Access to the media path is often difficult because of the complex mechanical design in existing devices. The media path may be located within the interior of the device making it very difficult to remove a jammed media sheet. Further, the user may have access to a limited section of the media path and be able to remove only a portion of the jammed media sheet. A torn remainder is left in the device that must somehow be removed prior to restarting image formation. 
   Another user intervention requires mounting cartridges within the device. Cartridge mounting may occur initially when the machine is first used, or throughout the device life to replace exhausted cartridges. The complex design again makes it difficult for the user to access the cartridges. Difficult cartridge mounting locations may also result in the user getting toner on their hands and fingers by inadvertently contacting the toner outlet on the cartridge. 
   Some existing devices provide for an adjustable media path and cartridge mounts to ease the user intervention. The media path and cartridge mounts may be positionable between an operational position during image formation, and a non-operational position to ease user access for media jam removal and cartridge installation respectively. It is important that these adjustable elements be accurately located in the operational position. Inaccurate locating of the elements may result in image forming defects, increased media jams, and other detrimental effects. 
   Further, the device should be constructed in an economical manner. Price is one of the leading factors when a user makes a purchasing decision. Improvements to user intervention should add to functionability, but not at a price that will drive away potential users. 
   SUMMARY 
   The present invention is directed to an image forming device having a main body and a movable subunit. In one embodiment, the subunit is movable between a first orientation that is spaced from the main body, and a second orientation that is either in contact with or closely located to the main body. A developer member is positioned within the main body, and a photoconductive member is positioned on the subunit. In the first orientation, the developer member and photoconductive member are spaced apart. Image formation occurs when the subunit is in the second orientation as toner is transferred from the developer member to the photoconductive member. 
   In one embodiment, an imaging device is positioned within the main body. One or more photoconductive members are positioned on a subunit that is movable relative to the main body. In a first orientation, the photoconductive members are spaced from the imaging device. In a second orientation, the photoconductive members are positioned within the main body and the imaging device can form an electrostatic latent image on the photoconductive members during image forming operations. 
   In another embodiment, a developer unit is located within the main body. The developer unit may include one or more of a developer member, toner sump, and agitating members. A photoconductive unit is connected to the subunit and may include one or more of a photoconductive member, a charger, a cleaning unit, and an auger. When the subunit is in a first orientation, the developer units and the photoconductive units are accessible to a user. In a second orientation, the subunit is closed and the photoconductive member of each photoconductive unit is mounted against a developer member of each developer unit. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view of one embodiment of an image forming device constructed according to the present invention; 
       FIG. 2  is a cross-sectional view of an image forming unit constructed according to one embodiment of the present invention; 
       FIG. 3  is a perspective view of a developer unit constructed according to one embodiment of the present invention; 
       FIG. 4  is a perspective view of a photoconductor unit constructed according to one embodiment of the present invention; 
       FIG. 5  is a cut-away side view of a subunit pivoted away from the main body according to one embodiment of the present invention; 
       FIG. 6  is a partial perspective view of one side of the developer unit constructed according to one embodiment of the present invention; 
       FIG. 7  is a partial perspective view of a second side of the developer unit constructed according to one embodiment of the present invention; and 
       FIG. 8  is a partial perspective view of one side of the photoconductor unit according to one embodiment of the present invention. 
   

   DETAILED DESCRIPTION 
     FIG. 1  depicts a representative image forming device, such as a printer, indicated generally by the numeral  10 . The image forming device  10  comprises a main body  12  and a subunit  13 . A media tray  14  with a pick mechanism  16 , or a manual input  32 , are conduits for introducing media sheets in the device  10 . The media tray  14  is preferably removable for refilling, and located on a lower section of the device  10 . 
   Media sheets are moved from the input and fed into a primary media path. One or more registration rollers disposed along the media path aligns the print media and precisely controls its further movement along the media path. A media transport belt  20  forms a section of the media path for moving the media sheets past a plurality of image forming units  100 . Color printers typically include four image forming units  100  for printing with cyan, magenta, yellow, and black toner to produce a four-color image on the media sheet. 
   An imaging device  22  forms an electrical charge on a photoconductive member within the image forming units  100  as part of the image formation process. The media sheet with loose toner is then moved through a fuser  24  that adheres the toner to the media sheet. Exit rollers  26  rotate in a forward or a reverse direction to move the media sheet to an output tray  28  or a duplex path  30 . The duplex path  30  directs the inverted media sheet back through the image formation process for forming an image on a second side of the media sheet. 
   The image forming units  100  are constructed of a developer unit  40  and a photoconductor unit  50 . The developer unit  40 , including a developer member  45 , is positioned within the main body  12 . The photoconductor unit  50 , including a photoconductive member  51 , is mounted to the subunit  13 . In a closed orientation as illustrated in  FIG. 1 , the subunit  13  is positioned adjacent to the main body  12  with the photoconductive member  51  of the photoconductor unit  50  against the developer member  45  of the developer unit  40 . In an open orientation as illustrated in  FIG. 5 , the subunit  13  is moved away from the main body  12  separating the photoconductor unit  50  from the developer unit  40 . This configuration provides direct and easy user access to the developer unit  40 , photoconductor unit  50 , and the media path. It has been determined that the highest user intervention rates are at the developer unit  40 , photoconductor unit  50 , and media path. 
     FIG. 2  illustrates a cross-sectional view of the image forming unit  100  in the closed orientation. The developer unit  40  comprises an exterior housing  43  that forms a reservoir  41  for holding a supply of toner. One or more agitating members  42  are positioned within the reservoir  41  for agitating and moving the toner towards a toner adder roll  44  and the developer member  45 . Toner moves from the reservoir  41  via the one or more agitating members  42 , to the toner adder roll  44 , and finally is distributed to the developer member  45 . The developer unit  40  is structured with the developer member  45  on an exterior section where it is accessible for being in contact with the photoconductive member  51  as illustrated in  FIG. 3 . 
   The photoconductor unit  50  is illustrated in  FIG. 2  and comprises the photoconductive member  51 . In one embodiment, the photoconductive member  51  is an aluminum hollow-core drum coated with one or more layers of light-sensitive organic photoconductive materials. The photoconductor unit  50  may also include a charger  52  that applies an electrical charge to the photoconductive member  51  to receive an electrostatic latent image from the imaging device  22 . A cleaner blade  53  contacts the surface of the photoconductive member  51  to remove any toner that remains on the photoconductive member  51 . The residual toner is moved to a waste toner auger  54  and moved out of the photoconductor unit  50 . A pair of mounts (not illustrated) attaches the photoconductor unit  50  to the subunit  13 . As illustrated in  FIG. 4 , the photoconductive member  51  is mounted on an exterior of the photoconductor unit  50  so it may be placed in contact with the developer member  45 . 
   In this two-piece cartridge architecture, the developer unit  40  and photoconductor unit  50  are mounted to ensure good contact axially across a print zone between the developer member  45  in the developer unit  40  and the photoconductive member  51  in the photoconductor unit  50 . The mounting of each of the developer unit  40  and photoconductor unit  50  is important for the axial contact. 
   The developer unit  40  is located within the main body  12  along three separate dimensional planes. In a first plane, feet  81  extend from two sides of the developer unit  40 . One or more rollers  83  are positioned within the main body  12  and extend outward to support the feet  81 . In one embodiment illustrated in  FIGS. 6 and 7 , a first side ( FIG. 6 ) of the developer unit  40  is supported by two rollers  83 , and a second side ( FIG. 7 ) is supported by one roller  83 . The feet  81  are also used for mounting the developer unit  40  within the main body  12  as the feet  81  slide along the rollers  83 . In one embodiment, the rollers  83  rotate as the feet  81  slide along during installation and removal of the developer unit  40 . In another embodiment, rollers  83  are stationary and the rounded edge slides along the feet  81 . Guide rails  82  may extend outward from the main body  12  along each side of the developer unit  40  and align with the rollers  83  ( FIG. 5 ). 
   In a second plane, the developer unit  40  is biased by a plurality of electrical contacts  85  that include a biasing mechanism  84  mounted to the main body  12 . The electrical contacts  85  apply a force outward from the main body  12  (i.e., towards the right as illustrated in  FIG. 5 ). One embodiment of the electrical contacts is described in U.S. patent application Ser. No. 10/804,691 entitled “Variable Force Biasing Mechanism and Electrical Connection” filed on Mar. 1, 2004 and assigned to Lexmark International, Inc., the owner of the present application, and herein incorporated by reference in its entirety. In another embodiment, location in the second plane is accomplished by one or more biasing mechanisms  84  that extend between the main body and a back edge of the developer unit  40  as schematically illustrated in  FIG. 5 . 
   Developer unit  40  is located in a third plane by a biasing force applied against a pad  86  on a first side. The force is applied to the pad  86  by a roller  89  within the main body  12  to force the developer unit  40  laterally within the main body  12  (i.e., into the page as illustrated in  FIG. 5 ). The roller  89  is biased against the pad  86  by a biasing mechanism  98 , such as a torsion spring. This force pushes the gear side of developer unit  40  ( FIG. 7 ) against coupling members in the main body  12 . The contact member  88  on the second side abuts against a stop pin  87  within the main body  12  to position the developer unit  40  and control the lateral position. Stop pin  87  and roller  89  have rounded surfaces to compensate for movement of the developing unit  40  relative to the main body  12 . 
   The locating features that bias the developer unit  40  along the three separate dimensional planes allow the unit  40  to move in all three directions instead of being rigidly locked in a fixed position. This allows the nip force acting on the developer member  45  when contacting the photoconductive member  51  to position the developer unit  40  such that the developer member  45  axially contacts the photoconductive member  51  completely and with the necessary nip force. 
   The photoconductor unit  50  attaches to the subunit  13  as illustrated in  FIG. 5 . Mounts extend outward to attach to and place the photoconductor unit  50  on an inner side of the subunit  13 . In one embodiment, mounts are positioned on both ends of the photoconductor unit  50 . The mounts do not locate the photoconductor unit  50 , but rather provide a means for the unit  50  to remain attached to the subunit  13  in the open orientation. One embodiment of the mounts is disclosed in U.S. patent Ser. No. 10/804,551 entitled “Door Assembly for an Image Forming Device” filed concurrently with the present application, assigned to Lexmark International, Inc., and herein incorporated by reference in its entirety. 
   When the subunit  13  is in the closed orientation, the photoconductor unit  50  is located along three dimensional planes. In a first plane, ball bearings  90  are positioned at each end of the photoconductor member  51 . The ball bearings  90  locate within a block  91  within the main body  12 . In one embodiment as illustrated in  FIG. 8 , photoconductor member  51  is an elongated drum and the ball bearings  90  are positioned towards each end of the drum. 
   The photoconductor unit  50  is located in a second plane via stop features  92 . The stops  92  are positioned in the housing  56  of the photoconductor unit  50  and ensure the correct rotational position of the photoconductive member  50  onto the developer member  45 . When the subunit  13  is moved to the closed orientation and torque is applied to the coupler  99  from a driving mechanism within the main body  12 , the photoconductor unit  50  rotates and is located by the stops  92  seating against the ends of guide rails  82  in the main body  12  ( FIG. 5 ). In one embodiment, one stop  92  is positioned at each end of the photoconductor unit  50 . 
   Location in a third plane is established through a v-notch feature  93  in the photoconductor unit  50 . The v-notch features includes first and second edges that straddle a mating point  95  in the main body. In one embodiment, a v-notch feature  93  is positioned at opposing ends of the photoconductor unit  50  and each mates with a corresponding mating point  95  within the main body  12 . 
   When the device  10  is in the open orientation, the developer units  40  can be individually removed and replaced as necessary. By way of example and using the embodiment of  FIG. 5 , the upper developer unit  40  can be removed from the main body  40  without disturbing the remaining developer units  40 . In one embodiment, the developer unit  40  is removed by pulling the unit outward away from the main body  12 . A replacement developer unit  40  can be inserted into the resulting gap by applying an opposite force such that the developer unit  40  is located along the three dimensional planes. Likewise, any of the photoconductive units  50  can be removed and replaced from the subunit  13 . Again by way of example and using  FIG. 5  as an example, the second photoconductor unit  50  from the upper edge of the subunit may be removed without interfering with the remaining units  50 . In one embodiment, photoconductor unit  50  is removed by lifting the unit  50  from the mounts positioned on the subunit  13 . A replacement unit  50  is reinserted by attaching the mounts to the subunit. The photoconductor unit  50  is loosely attached to the subunit  13  to ease the burden of removing jammed sheets on the media path, and replacing the unit  50  on the subunit  13 . 
   The subunit  13  results in locating the photoconductive units  50  relative to the corresponding developer units  40 . As the subunit  13  closes and the driving mechanism in the main body rotates the coupler  99 , the photoconductive units  50  are located along the three dimensional planes. The developer units  40  are located along the three planes as the photoconductive member  51  abuts against the developer member  45 . This positioning of the photoconductive member  51  against the developer member  45  allows for toner to pass during the image formation process. In one embodiment, the only contact between the mating developer units  40  and photoconductive units  50  is the contact between the developer members  45  and the photoconductive members  51 . 
   The design provides for most of the developing forces acting on the image forming units  100  to be developed when the subunit  13  is initially placed into the closed orientation. For the developing unit  40 , forces are applied along each of the three planes. For the photoconductor unit  50 , the forces are completed once torque is applied through the coupler  99  and the stops  92  seat against the ends of guide rails  82  to completely locate the unit with the developer member  45  in contact with the photoconductive member  51 . Once the subunit  13  is opened, the forces are removed as the photoconductive member  51  moves away from the developer member  45 . 
   A two-piece cartridge design with pivoting subunit is disclosed in concurrently filed U.S. patent application Ser. No. 10/804,488 titled “Image Forming Device having a Door Assembly and Method of Use” which is assigned to Lexmark International, Inc., and incorporated herein by reference in its entirety. 
   The term “image forming device” and the like is used generally herein as a device that produces images on a media sheet  50 . Examples include but are not limited to a laser printer, ink-jet printer, fax machine, copier, and a multi-functional machine. One example of an image forming device is Model No. C750 referenced above. 
   The term “imaging device” refers to a device that arranges an electrical charge on the photoconductive element  51 . Various imaging devices may be used such as a laser printhead and a LED printhead. 
   A transport belt  20  is illustrated in the embodiments for moving the media sheets past the image forming units  100 , and as part of the subunit. In another embodiment, roller pairs are mounted to the subunit  13  and spaced along the media path. The roller pairs move the media sheets past the image forming units  100 . In one embodiment, each of the roller pairs is mounted on the subunit  13 . In another embodiment, one of the rollers is mounted on the subunit, and the corresponding roller of the pair is mounted on the main body  12 . In yet another embodiment, rollers may be positioned within the photoconductor unit  50 . 
   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, both the photoconductive member  51  and the developer member  45  are cylindrically shaped. 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.