Abstract:
A magnetic latch for removably latching a first member to a second member includes a magnet emitting a magnetic field carried by the first member and a magnetically attractive catch plate carried by the second member. A release mechanism is provided for moving the magnet relative to the catch plate from a first position in which the catch plate is strongly engaged with the magnetic field to a second position in which the catch plate is weakly engaged with the magnetic field. The release mechanism includes a lever, pivotally mounted to one of the first and second members and a biasing member carried by the other of the first and second members, the lever engaging the biasing member during pivoting of the lever. The release mechanism enables the magnetic engagement of the members to be broken with a relatively small applied force.

Description:
BACKGROUND 
   The exemplary embodiment relates to copiers and printers, and more particularly, to an improved apparatus and method for use in the clearance of jammed media sheets. 
   In a typical xerographic imaging device, such as a copier or printer, a photoconductive insulating member is charged to a uniform potential and thereafter exposed to a light image of an original document to be reproduced. The exposure discharges the photoconductive insulating surface in exposed or background areas and creates an electrostatic latent image on the member, which corresponds to the image areas contained within the document. Subsequently, the electrostatic latent image on the photoconductive insulating surface is made visible by developing the image with a developing material. Generally, the developing material comprises toner particles adhering triboelectrically to carrier granules. The developed image is subsequently transferred to a print medium, such as a sheet of paper. The fusing of the toner onto the paper is generally accomplished by applying heat to the toner with a heated roller and application of pressure. 
   The sheets of paper are conveyed through the imaging device by a conveyor system comprising baffles which incorporate sheet moving devices, such as rollers, and guides including parallel plates which constrain the sheets to move in a desired direction. Occasionally, the paper can become curled, skewed, or otherwise misaligned causing paper jams to occur. When a paper jam occurs, the jammed sheets are typically removed by an operator. To access the jammed sheets, an operator may pivot one of the guides away from the other and remove the jammed paper. To keep the guides closed when paper is moving at high speed through the baffle, the guides are held in place by latches, which in some cases, may be magnetic. 
   Magnetic latches have advantages for applications where openings and closings are frequent. A magnetic latch provides an inexpensive, durable, and simple closure device. One disadvantage of magnetic latches is the force required to separate the magnet from its catch plate. The strength of the magnet is greatest when the magnet or its strike plates are in direct contact with the metallic catch plate to which the magnet is attracted. The intensity of the magnetic field dissipates rapidly as the catch plate is moved from the magnet during the process of opening. 
   INCORPORATION BY REFERENCE 
   The following references, the disclosures of which are incorporated herein in their entireties by reference, are mentioned: 
   U.S. Pat. No. 6,607,223, issued, Aug. 19, 2003, entitled MOLDED MAGNETIC CATCH ASSEMBLY, by Paul F. Mastro, discloses a magnetic catch suitable for holding a door of an electrophotographic device in a closed position. 
   U.S. Pat. No. 6,976,715, issued Dec. 20, 2005, entitled MAGNETIC LATCH AND RELEASE APPARATUS, by Donald J. Lyon, discloses a magnetic latch mechanism including a magnetically attractive catch plate. The catch plate includes a rod with first and second sections of different cross sectional diameter. The first section strongly engages the magnetic field when located in a position proximate to the magnet. The second section weakly engages the magnetic field when moved to the position proximate the magnet. 
   U.S. Pat. No. 6,757,506, issued Jun. 29, 2004, entitled MEDIA CLEARANCE MEMBER, by Arthur H. Kahn, discloses a media clearance apparatus including a member having a length, a thickness, and a width, and a first end and a second end. The member is securable along a portion of the member to a secondary member and is functionally operational such that one end of the member is movable from a first position out of contact with a media path into a second position in contact with the media path. 
   BRIEF DESCRIPTION 
   In accordance with one aspect of the exemplary embodiment, a magnetic latch for removably latching a first member to a second member includes a magnet emitting a magnetic field carried by the first member and a magnetically attractive catch plate carried by the second member. A release mechanism is provided for moving the magnet relative to the catch plate from a first position in which the catch plate is strongly engaged with the magnetic field to a second position in which the catch plate is weakly engaged with the magnetic field. The release mechanism includes a lever, pivotally mounted to one of the first and second members, and a biasing member carried by the other of the first and second members, the lever engaging the biasing member during pivoting of the lever. 
   In another aspect, an assembly includes a first member and a second member which define a paper path therebetween. The first member is movable from a position adjacent the paper path to a position spaced from the paper path. A magnet emitting a magnetic field is mounted to the first member. A magnetically attractive catch plate is mounted to the second member. A release mechanism is provided for moving the magnet relative to the catch plate from a first position, in which the catch plate is strongly engaged with the magnetic field, to a second position, in which the catch plate is weakly engaged with the magnetic field. The release mechanism includes a lever, pivotally mounted to one of the first and second members, and a biasing member, mounted to the other of the first and second members. The lever engages the biasing member during pivoting of the lever. 
   In another aspect, a method for unlatching a first member from a second member is provided. The method includes applying a force to a first end of a lever whereby a second end of the lever engages a biasing member on the second member. The lever is pivotally connected with the first member intermediate the first and second ends. The pivoting of the lever moves a magnet carried by one of the first and second members relative to a magnetically attractive catch plate carried by the other of the first and second members from a first position, in which the catch plate is strongly engaged with the magnetic field, to a second position, in which the catch plate is weakly engaged with the magnetic field. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view of a printing system in accordance with one aspect of the exemplary embodiment; 
       FIG. 2  is an enlarged perspective view of one of the baffles of  FIG. 1 ; 
       FIG. 3  is a side sectional view of the release mechanism of  FIG. 2 ; 
       FIG. 4  is a perspective view of the release mechanism of  FIG. 3  with the lever pivoted to a release position by grasping the lever and handle of the release mechanism between the thumb and forefinger; and 
       FIG. 5  is a perspective view of the baffle of  FIG. 2  after pivoting the plastic guide member to a position suitable for jam clearance. 
   

   DETAILED DESCRIPTION 
   With reference to  FIG. 1 , a printing or copying device  10  (generally referred to herein as a printing system) comprises a marking engine  12 , a print media source  14 , and a finishing device  16 , all coupled by a print media conveyor  18 . The print media source supplies paper or other print media to the imaging member for printing and may include one or more paper trays. An image input device (not shown) supplies the printing system  10  with images to be printed. 
   The illustrated marking engine employs xerographic printing technology, in which an electrostatic image is formed on an imaging member  20 , such as a photoreceptor belt or drum, and coated with a toner material. The developed image is then transferred and fused to paper or another print medium by a fuser  22 , e.g., by application of heat and pressure. However, imaging members employing other printing technologies can be employed, such as marking engines employing ink jet transfer, thermal impact printing, or so forth. While a single marking engine is illustrated, it is contemplated that multiple marking engines may be employed in the printing system. The finisher  16  provides finishing capabilities such as one or more of stacking, collation, stapling, folding, hole-punching, binding, postage stamping, and the like. The finisher includes one or more print media destinations. While a single destination is illustrated, the printing system may include two, three, four, or more print media destinations. The finisher deposits each sheet after the processing in one of the print media destinations, which may be trays, pans, or so forth. 
   The print media conveyor  18  is controllable to acquire sheets  24  of a selected print medium from the print media source trays  14 , transfer each acquired sheet to the marking engine  12  to perform selected marking tasks, and transfer each sheet to the finisher  16  to perform finishing tasks. 
   The image input device can include a built-in optical scanner, which can be used to scan a document such as book pages, a stack of printed pages, or the like, to create a digital image of the scanned document that is reproduced by printing operations performed by the printing system  10 . Alternatively or additionally, the image input device can include a link to a remote source. For example, a print job can be electronically delivered to the control system of the printer via a wired or wireless connection to a digital network that interconnects, for example, personal computers or other digital devices. 
   The printing system  10  executes print jobs. Print job execution involves printing images, such as selected text, line graphics, photographs, and the like on front, back, or front and back sides or pages of one or more sheets of paper or other print media. Execution of the print job may also involve collating the sheets in a certain order. Still further, the print job may include folding, stapling, punching holes into, or otherwise physically manipulating or binding the sheets. 
   The print media conveyor system  18  includes one or more baffles  30 ,  32 ,  34  which are used to guide the sheets  24  of paper along a predetermined path. Since the baffles may be similarly configured, only one is described. Each of the baffles includes first and second members  36 ,  38 , one of which is a stationary member and the other, a movable member. 
   As shown in  FIGS. 2 and 3 , each of the members  36 ,  38  may include a guide plate  40 ,  42 , respectively, which is generally wider (in the cross process direction) than the width of a sheet  24  of print media. During printing, the guide plates are arranged in parallel to constrain the sheets for movement along a media path  44  ( FIG. 1 ) defined between the plates  40 ,  42 . Typically, the movable member  36  is formed from plastic and the stationary member  38 , or at least the guide plate  42 , is formed from metal. The sheets  24  are conveyed along the paper path  44  by suitable sheet moving devices  46 , such as rollers, spherical balls, or air jets. In the illustrated embodiment, the stationary guide member  38  includes parallel, spaced rollers  46  which protrude through slots  48  in the guide plate  40 ,  42  and which are arranged to convey the paper sheets in the direction of arrow A (z direction, using the axis notation shown in  FIG. 3 ). Sheets of paper enter the baffle through an inlet slot at an upstream end of the baffle and exit the baffle through an outlet slot at a downstream end. While the illustrated baffle  30  is shown in a generally vertical orientation in  FIG. 3 , it is to be appreciated that the baffle  30  may be arranged to convey the paper generally horizontally or in another predefined direction. 
   The movable member  36  is movable between a position adjacent the media path  44  to a position spaced from the media path. In the spaced position, an operator can remove jammed sheets of paper from the baffle  30 . In the closed position, sidewalls  50  ( FIG. 3 ) of one or both guide members  36 ,  38  prevent access to the paper. The illustrated movable member  36  is pivotable in the direction of arrow B, around a pivot axis as shown in  FIG. 1 . 
   As shown in  FIG. 3 , a magnetic latch  52  maintains the guide members  36 ,  38  in a closed relationship during printing. The latch  52  includes a permanent magnet  54 , carried by one of the guide members (the movable guide member  36  in the illustrated embodiment) and a catch plate  56  carried by the other guide member  38  (the stationary guide member in the illustrated embodiment). The illustrated magnet  54  is fixedly mounted to the first member  36  for movement therewith and the catch plate  56  is fixedly mounted to the second member  38 . 
   A release mechanism  60  is configured for effecting relative movement between the magnet  54  and the catch plate  56 , from a position in which the catch plate is strongly attracted by the magnetic field to a position in which the catch plate is weakly attracted, if at all. The release mechanism  60  includes a handle  62  and a lever  64  pivotally connected with the handle. The illustrated handle  62  extends from the moveable guide member  36  in a direction generally transverse to the paper path (x direction) and includes a generally planar grasping portion  68  at a distal end  69 . The illustrated handle  62  is integrally formed with (e.g., by molding) or otherwise rigidly attached to the movable member  36  to be moveable therewith. The handle allows an operator to pivot the movable guide member  36  away from the stationary guide member  38  prior to conducting a jam clearance procedure. In particular, an operator may grasp the distal end  68  and apply a force to the handle. 
   The catch plate  56  may be in the form of a planar flange which extends transversely from the stationary guide member  38 . In one embodiment, the catch plate  56  is an extension of the guide plate  42 . Alternatively, the flange may be formed by outward bending of a metal tab, which is integrally formed with a sidewall of the stationary member, to a position in which the tab extends from the side wall at an angle of approximately 90°. In yet another embodiment, the catch plate  56  may be welded, attached with fixing members, such as screws or bolts, or otherwise mounted to the stationary guide member. The catch plate  56  may be formed from any suitable magnetically attractive material, such as a ferromagnetic material, e.g., iron, nickel or an alloy thereof, such as steel. 
   The exemplary lever  64  is pivotally connected with one of the movable and stationary guide members for biasing the other of the movable and stationary guide members away from the other to pry the magnet away from the catch plate a sufficient distance for the magnetic attraction force to be largely dissipated. In one embodiment, the handle  62  includes a magnet housing  70  which depends from the grasping portion  68  of the handle intermediate the distal end and the guide member  36 . The housing supports the magnet  54  between parallel strike plates  72 ,  74 . The strike plates can be of any metallic or other material through which a magnetic field can be transmitted. 
   As shown in  FIG. 3 , the lever  64  may be disposed intermediate the handle  62  and the catch plate  56  to bias the handle away from the catch plate. For example, the lever  64  may be pivotally connected at its fulcrum  76  to the handle. In one embodiment, the lever defines a pair of tabs  78  which are received in corresponding slots  80  in support plates  82  extending from an underside the handle ( FIG. 4 ). The tabs  78  have a generally circular cross section for ease of rotation within the slots. 
   A first portion  84  of the lever  64  may be generally planar and extend toward the distal end of the handle. A second portion  86  of the lever may be angled away from the first portion  84 , e.g., curved toward the catch plate, and define an engagement surface  88  for contacting the catch plate  56 . In the closed position, a distal end  90  of the lever first portion  84  is spaced from the distal end  69  of the handle  62  by a sort distance  92  which allows the operator to grasp the tips  69 ,  90  of the handle and lever between the fingers and thumb of one hand ( FIG. 4 ). For example, the spacing  92  may be about 0.5 to 5 cm, e.g., about 1-3 cm. By exerting a force on the lever and handle, the lever is pivoted to a position as shown in  FIG. 4 , where the distal end  90  is closer to the handle, e.g., touching the handle  62 . 
   The catch plate  56  includes a distal portion  94  which serves as a biasing member. During pivoting, the engagement surface  86  slides transversely along the distal portion  94  of catch plate  56 , thereby increasing a distance between the pivot point and the catch plate and causing the magnet  54  to move away from the catch plate  56  by a distance  96 . Because of the lever action (the distance  96  is substantially less than the distance  92 ), it is much easier for the operator to overcome the force of the magnet that would be the case if the handle  62  alone were pushed to break the magnetic attraction. Once the magnet  54  is spaced slightly from the catch plate  56 , the magnetic attraction is largely dissipated. The lever can then be released, and the handle  62  can be used to pivot the movable guide member  36  away from the stationary member  38 . Thereafter, an operator may remove any sheets of paper jammed therebetween. 
   While the illustrated lever  64  is biased against the catch plate  56 , it is also contemplated that the biasing member for the lever may be provided by another portion of the stationary guide member  38 , e.g., a flange laterally spaced (in the z direction) from the catch plate  56 . 
   The lever  64  may be formed of plastic, metal, or other suitable material with sufficient rigidity to withstand the forces generated in releasing the magnet. 
   As will be appreciated, in another embodiment, the handle  62  may incorporate the catch plate, and the magnet may be supported on the stationary member  38  with a suitable biasing member extending transversely from the stationary member whereby the lever may engage the biasing member to displace the handle from the magnet. 
   In general, the printing system  10  may include several magnetic latches  52 , formed according to the exemplary embodiment. Typically, the printing system includes at least two baffles  30 ,  32 ,  34  of the type described. Additionally, the conveyor system  18  may also include diverters, inverters, interposers, and the like, as known in the art some or all of which may also include a magnetic latch formed according to the exemplary embodiment. While the magnetic latch has been described with particular reference to the securement of components of the conveyor system  18 , it may find other applications as a closure member for a door, access panel, or the like. 
   Additionally, while the conveyor system  18  has been described in terms of a printing system, it is also contemplated that the conveyor system may form a part of another device in which sheets of flexible media, such as paper, plastic, or the like, are conveyed between the first and second members, such as a sheet sorting device, bookbinding machine, or the like. 
   It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.