Abstract:
A cradle for a fusing assembly including end tabs or protrusions for supporting and pivoting on a side wall. The cradle functionally associates with the side walls and is adapted to angularly pivot between a first position and a second position.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates generally to a fusing system in an electrophotographic printing machine, and more particularly to an improved system for supporting a roll in a fuser device.  
         BACKGROUND OF THE INVENTION  
         [0002]    In an electrophotographic printing process, a photoconductive member is charged to a substantially uniform potential so as to sensitize the surface thereof. The charged portion of the photoconductive member is exposed to a light image of an original document being reproduced. Exposure of the charged photoconductive member selectively dissipates the charges thereon in the irradiated areas. This records an electrostatic latent image on the photoconductive member corresponding to the informational areas contained within the original document. After the electrostatic latent image is recorded on the photoconductive member, the latent image is developed by bringing a developer material into contact therewith. Generally, the developer material comprises toner particles adhering triboelectrically to carrier granules. The toner particles are attracted from the carrier granules to the latent image forming a toner powder image on the photoconductive member. The toner powder image is then transferred from the photoconductive member to a copy sheet. The toner particles are heated to permanently affix the powder image to the copy sheet.  
           [0003]    While existing fuser frames and load arm systems are generally suitable, improvements in development quality and performance are desired. Existing systems may include pivot pins that are stacked, welded, or otherwise fastened to the side frame for mounting load arms in the fuser assemblies which must be tightly controlled to insure the strength and security of the pivot pin.  
           [0004]    Reference is made to U.S. Pat. No. 5,848,331 relating to a fuser roll housing.  
           [0005]    All documents cited herein, including the foregoing, are incorporated herein by reference in their entireties.  
         SUMMARY OF THE INVENTION  
         [0006]    The principles described herein provide for a cradle system for use with a roll in an electrophotographic printing or copying system. This system utilizes a cradle and side frames including features formed therein to provide an assembly that allows the cradle to be supported and to pivot at pivot points while being supported on the side frames. This improved design eliminates the need for support pins, fastening issues and associated assembly costs. Support pins may apply generally high cantilever loads to fuser frames which under certain conditions may bend. This improved system generally eliminates cantilever loading of the fuser frames. A need exists for such an improved roll support system for printing and copying machines to resist high load between a roll pair, such as a pressure roll and fuser roll. An improved cost-effective cradle which eliminates cantilever loading of the fuser frames, parts, pins and associated manufacturing steps would be beneficial.  
           [0007]    In accordance with one aspect of the invention, there is provided a roll support system in an electrophotographic apparatus including a member including a wall. The wall has a longitudinal length, a first end and a second end. A pair of roll support members are formed from the wall and extend a distance from the wall. The roll support members are spaced apart from one another. The wall includes a first protrusion defining the first end and a second protrusion defining the second end. At least one of the first and second protrusions include a notch at an edge. The notch is adapted for selective positioning of the member with respect to a frame. The pair of roll support members is adapted to support a roll and to pivot between a first position and a second position.  
           [0008]    Pursuant to another aspect of the invention, there is provided a support system for a roll in at least one of a printing and copying apparatus including a frame and a cradle. The frame has a first side and a second side. Each of the first side and second side having a length, width and thickness. The first side and second side each having an opening of a first selected shape. The cradle has a length and width and includes a first protrusion and a second protrusion defining a first end and a second end. At least one of the first and second protrusions include an opening of a second selected shape that is positioned opposed to the side opening such that the cradle is supported at the first and second protrusions by the first side and the second side. The cradle is adapted to angularly move with respect to the frame.  
           [0009]    Pursuant to a further aspect of the invention, there is provided an electrophotographic apparatus including a fuser roll, a pressure roll, a frame system, and a cradle. The pressure roll is associated with the fuser roll. The frame system supports the fuser roll and the pressure roll. The frame system includes a first side and second side. Each of the first side and second side have a length, width and thickness. The first side and second side each have an opening of a selected shape. The cradle supports the pressure roll between the first side and the second side of the frame system. The cradle includes a wall, a length and a width, and a first protrusion and a second protrusion defining a first end and a second end of the wall. At least one of the first and second protrusions include an opening of a selected shape. A plurality of pressure roll support members extend a distance from the wall. The openings of the first protrusion and the second protrusion are positioned downward and the openings of the first side and the second side are situated upward such that the first protrusion and the second protrusion are supported by the first side and the second side and wherein the cradle is adapted to angularly move with respect to the frame system.  
           [0010]    Pursuant to another aspect of the invention, there is provided a roll support system in an electrophotographic apparatus including a member including a wall. The wall has a longitudinal length, a first end and a second end. A plurality of roll support members extend a distance from the wall. The plurality of roll support members are spaced apart from one another. The wall includes a first protrusion defining the first end and a second protrusion defining the second end. At least one of the first and second protrusions including a notch at an edge. The notch is adapted for selective positioning of the member with respect to a frame. The plurality of roll support members are adapted to support a roll and the member is adapted to pivot between a first position and a second position.  
           [0011]    Pursuant to yet another aspect of the invention, there is provided a cradle including a wall having a longitudinal length, a first end, a second end, and an angle for purposes of support, rigidity, and strength. A pair of roll support members are formed from the wall and extend a distance from the wall. The roll support members are spaced apart from one another and are used to hold and support a roll such as a pressure roll. A first protrusion or end tab is located at one end of the cradle and a second protrusion or end tab is located at the other end of which at least one end tab includes a notch at an edge thereof. The notch is for selective positioning of the cradle with respect to a frame. The cradle and roll support members pivot between a first position and a second position.  
           [0012]    Still other aspects and advantages of the present invention and methods of construction of the same will become readily apparent to those skilled in the art from the following detailed description, wherein embodiments are shown and described, simply by way of illustration. As will be realized, the invention is capable of other and different embodiments and methods of construction, and its several details are capable of modification and interchangeability in various obvious respects, all without departing from the invention. Accordingly, the drawing and description are to be regarded as illustrative in nature, and not as restrictive. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is a schematic elevational view of an electrophotographic machine utilizing a cradle;  
         [0014]    [0014]FIG. 2 is an end view of an assembly including an embodiment of the cradle;  
         [0015]    [0015]FIG. 3 is a perspective view illustrating an embodiment of the cradle supported by side frames;  
         [0016]    [0016]FIG. 4 illustrates a notch feature of one end tab of the cradle and an associated opening and notch features on one of the side frames;  
         [0017]    [0017]FIG. 5 illustrates an embodiment of an opposite end tab of the cradle and an associated opening and notch on the opposite side frame;  
         [0018]    [0018]FIG. 6 illustrates an end view of FIG. 5 showing the end tab and side frame; and  
         [0019]    [0019]FIG. 7 illustrates an embodiment of an assembly including a cradle having a bottom shield. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]    While the principles and embodiments of the present invention will be described in connection with an electrostatographic reproduction apparatus, it should be understood that the present invention is not limited to that embodiment or to that application. Therefore, it should be understood that the principles of the present invention and embodiments extend to all alternatives, modifications, and equivalents thereof.  
         [0021]    Referring to FIG. 1 of the drawings, schematically illustrated is an original document is positioned in a document handler  27  on a raster input scanner (RIS) indicated generally by reference numeral  28 . The RIS contains document illumination lamps, optics, a mechanical scanning drive and a charge coupled device (CCD) array. The RIS captures the entire original document and converts it to a series of raster scan lines. This information is transmitted to an electronic subsystem (ESS) which controls a raster output scanner (ROS) described below.  
         [0022]    An electrophotographic printing machine may generally include a photoconductive belt  10 . The photoconductive belt  10  may be made from a photoconductive material coated on a ground layer, which, in turn, is coated on an anti-curl backing layer. Belt  10  moves in the direction of arrow  13  to advance successive portions sequentially through the various processing stations disposed about the path of movement thereof. Belt  10  is entrained about stripping roller  14 , tensioning roller  20  and drive roller  16 . As roller  16  rotates, it advances belt  10  in the direction of arrow  13 .  
         [0023]    Initially, a portion of the photoconductive surface passes through charging station A. At charging station A, a corona generating device indicated generally by the reference numeral  22  charges the photoconductive belt  10  to a relatively high, substantially uniform potential.  
         [0024]    At an exposure station, B, a controller or electronic subsystem (ESS), indicated generally by reference numeral  29 , receives the image signals representing the desired output image and processes these signals to convert them to a continuous tone or greyscale rendition of the image which is transmitted to a modulated output generator, for example the raster output scanner (ROS), indicated generally by reference numeral  30 . Preferably, ESS  29  is a self-contained, dedicated minicomputer. The image signals transmitted to ESS  29  may originate from a RIS as described above or from a computer, thereby enabling the electrophotographic printing machine to serve as a remotely located printer for one or more computers. Alternatively, the printer may serve as a dedicated printer for a high-speed computer. The signals from ESS  29 , corresponding to the continuous tone image desired to be reproduced by the printing machine, are transmitted to ROS  30 . ROS  30  includes a laser with rotating polygon mirror blocks. The ROS will expose the photoconductive belt to record an electrostatic latent image thereon corresponding to the continuous tone image received from ESS  29 . As an alternative, ROS  30  may employ a linear array of light emitting diodes (LEDs) arranged to illuminate the charged portion of photoconductive belt  10  on a raster-by-raster basis.  
         [0025]    After the electrostatic latent image has been recorded on photoconductive surface  12 , belt  10  advances the latent image to a development station, C, where toner, in the form of liquid or dry particles, is electrostatically attracted to the latent image using commonly known techniques. The latent image attracts toner particles from the carrier granules forming a toner powder image thereon. As successive electrostatic latent images are developed, toner particles are depleted from the developer material. A toner particle dispenser, indicated generally by the reference numeral  44 , dispenses toner particles into developer housing  46  of developer unit  38 .  
         [0026]    After the electrostatic latent image is developed, the toner powder image present on belt  10  advances to transfer station D. A print sheet  48  is advanced to the transfer station, D, by a sheet feeding apparatus,  50 . Preferably, sheet feeding apparatus  50  includes a nudger roll  51  which feeds the uppermost sheet of stack  54  to nip  55  formed by feed roll  52  and retard roll  53 . Feed roll  52  rotates to advance the sheet from stack  54  into vertical transport  56 . Vertical transport  56  directs the advancing sheet  48  of support material into the registration transport  120  of the invention herein, described in detail below, past image transfer station D to receive an image from photoreceptor belt  10  in a timed sequence so that the toner powder image formed thereon contacts the advancing sheet  48  at transfer station D. Transfer station D includes a corona generating device  58  which sprays ions onto the back side of sheet  48 . This attracts the toner powder image from photoconductive surface  12  to sheet  48 . The sheet is then detacked from the photoreceptor by corona generating device  59  which sprays oppositely charged ions onto the back side of sheet  48  to assist in removing the sheet from the photoreceptor. After transfer, sheet  48  continues to move in the direction of arrow  60  by way of belt transport  62  which advances sheet  48  to fusing station F of the invention herein, described in detail below.  
         [0027]    Fusing station includes a fuser assembly  200  which permanently affixes the transferred toner powder image to the copy sheet. Fuser assembly  200  may include a heated fuser roller  240  and a pressure roller  230  with the powder image on the copy sheet contacting fuser roller  240 . The pressure roller is loaded against the fuser roller to provide the necessary pressure to fix the toner powder image to the copy sheet. The fuser roll is internally heated by a quartz lamp (not shown). Release agent, stored in a reservoir (not shown), is pumped to a metering roll (not shown). A trim blade (not shown) trims off the excess release agent. The release agent transfers to a donor roll (not shown) and then to the fuser roll  240 . Or alternatively, release agent is stored in a presoaked web (not shown) and applied to the fuser roll  240  by pressing the web against fuser roll  240  and advancing the web at a slow speed.  
         [0028]    The sheet then passes through fuser  200  where the image is permanently fixed or fused to the sheet. After passing through fuser  200 , a gate  80  either allows the sheet to move directly via output  84  to a finisher or stacker, or deflects the sheet into the duplex path  100 , specifically, first into single sheet inverter  82  here. That is, if the sheet is either a simplex sheet, or a completed duplex sheet having both side one and side two images formed thereon, the sheet will be conveyed via gate  80  directly to output  84 . However, if the sheet is being duplexed and is then only printed with a side one image, the gate  80  will be positioned to deflect that sheet into the inverter  82  and into the duplex loop path  100 , where that sheet will be inverted and then fed to acceleration nip  102  and belt transports  110 , for recirculation back through transfer station D and fuser assembly  200  for receiving and permanently fixing the side two image to the backside of that duplex sheet, before it exits via exit path  84 .  
         [0029]    After the print sheet is separated from photoconductive surface  12  of belt  10 , the residual toner/developer and paper fiber particles adhering to photoconductive surface  12  are removed therefrom at cleaning station E. Cleaning station E includes a rotatably mounted fibrous brush in contact with photoconductive surface  12  to disturb and remove paper fibers and a cleaning blade to remove the nontransferred toner particles. The blade may be configured in either a wiper or doctor position depending on the application. Subsequent to cleaning, a discharge lamp (not shown) floods photoconductive surface  12  with light to dissipate any residual electrostatic charge remaining thereon prior to the charging thereof for the next successive imaging cycle.  
         [0030]    The various machine functions are regulated by controller  29 . The controller is preferably a programmable microprocessor which controls all of the machine functions hereinbefore described. The controller provides a comparison count of the copy sheets, the number of documents being recirculated, the number of copy sheets selected by the operator, time delays, jam corrections, etc. The control of all of the exemplary systems heretofore described may be accomplished by conventional control switch inputs from the printing machine consoles selected by the operator. Conventional sheet path sensors or switches may be utilized to keep track of the position of the document and the copy sheets.  
         [0031]    [0031]FIG. 2 illustrates an end view of a fuser assembly  200  including a cradle  202  supported at a side frame  212  (side frame  214  not shown). The cradle  202  may be formed in one-piece member or be made of two pieces connected or formed together to make one-piece that spans between the side frames  212 ,  214 . The cradle  202  functions to replace two separate load arms for support of a pressure roller  230  and may pivot. The cradle  202  may be formed from sheet metal. The fuser roll  240  and the pressure roll  230  may form a nip  260  therebetween.  
         [0032]    Shown in FIG. 2 is the arcuate range of motion of the cradle  202  in the fuser assembly  200  which allows movement of the pressure roll  230  with respect to the fuser roll  240 . The angular motion (β+θ) of the cradle  202  may range up to about 120 degrees, for example, up to 60 degrees, β, from the imaginary line  203  in one direction and up to about 60 degrees, θ, from the imaginary line  203  in the other direction. In an embodiment, β ranges up to 15 degrees and θ ranges up to 30 degrees. The relative movement between the cradle  202  and the side frame  212 ,  214  defines a generally low friction rocking motion, and generally not a high friction sliding action.  
         [0033]    In an embodiment, the cradle  202  may pivot about a straight line that intersects the two contact points formed between the cradle and the side frames, at the bottom surface of the end tabs  204 ,  206  and at the bottom of each notch  216 ,  218 . The imaginary line  203  is a reference line from which the angular position can be measured. The notches  216 ,  218  of the side frames  212 ,  214  and the notch  220  at one end of the cradle  202  function together as a pivot and positioning system. The pivot point and imaginary line  203  are located on one side of the cradle  202  and a spring  250  is spaced apart therefrom and connected to roll support arms  224 ,  226  and associated with the side frames  212 ,  214 . The end tabs  204 ,  206  of the cradle  202  rest on the edges of the side frames  212 ,  214 .  
         [0034]    FIG&#39;S.  3 ,  4 , and  5  are perspective views of an embodiment of the cradle  202  supported by side frames  212 ,  214 . The cradle  202  spans the distance between the first side frame  212  and the second side frame  214  and the end tabs  204 ,  206  of the cradle  202  extend beyond side frames  212 ,  214 . The cradle  202  pivots on the end tabs  204 ,  206  and rest on the side frames  212 ,  214 . As a result, the load of the cradle and components, such as a roll, is applied generally coplanar with the side frames  212 ,  214 , which eliminates the bending load associated with a pivot pin.  
         [0035]    At least one of the side frames  212 ,  214  define an opening and/or a notch  216  to cooperate with the notch  220  of the end tab  204  to limit movement of the cradle  202  in the Y direction and angular rotation of the cradle  202 . At least one end tab  204 ,  206  includes a notch to cooperate with a side frame  212 ,  214 . Notch  220  may be located on either end tab  204 ,  206 . In an embodiment, the notch  220  of the end tab  204  and the notch  216  of the side frame  212  may be inverted to the other and functionally cooperate with the other when the cradle  202  is supported by the side frames  212 ,  214 . The notch  220  of the cradle  202  and the notch  216  of the side frame  212  may include a flat bottom and non-parallel sides extending from the bottom. The notches  216 ,  218 ,  220  may include a concave surface. The sides of the notches  216 ,  218 ,  220  may form a V-like shape. The notches  216 ,  218 ,  220  may include a selected shape and the cradle  202  may pivot a range defined by a selected shape formed in the side frame  212 ,  214 . Each end tab  204 ,  206  may have more than one notch for selective positioning. The relative movement of the cradle  202  may be characterized by a rocking movement with respect to the side frame  212 ,  214 .  
         [0036]    [0036]FIG. 4 illustrates the notch feature of end tab  204  of the cradle  202  and its associated opening  216  on the side frame  212 . In embodiments, the cradle  202  may be positioned and adjusted in the X, Y, and Z directions in an amount depending on the size and position of the notches  216 ,  218 ,  220 . FIG. 5 illustrates an embodiment of the end tab  206  of the cradle  202  and an opening and notch  218  on the side frame  214 . FIG. 6 illustrates an end view of FIG. 5 showing embodiment of the cradle  202  and side frame  214 . An end tab  206  is supported on a notch  218  having a flat bottom. Various notch shapes are envisioned including V shape, circular, triangular and concave shapes. FIG. 7 illustrates a further embodiment of a cradle  230  including a bottom shield sufficient in size to partially cover a roll such as a pressure roll.  
         [0037]    In embodiments, a thermoplastic bottom housing may be associated with the side frames and cradle in the fusing assembly. The side frames may be made of sheet metal. The bottom cover may be made of a plastic or metal. The end tabs of the cradle may be put in place in the frame by inserting the tab first into the bearing hole and then into the notch, inserting the tabs from a side opening and into the notch, or inserting the tab into an independent notch spaced from the bearing hole. The end tabs at each end of the cradle may include one or more notches. The notches may be slots, openings, or semi-circular shapes where there is positive clearance for the cradle to pivot. The cradle may be self-aligning on the frames. The cradle and pivot features may be used in other than fusing systems where support of a member and pivot features are desired. The thickness of the metal may range from about 1 mm to about 12.7 mm, for example, about 1½ mm. The length of the cradle and roll may range from about 8 inches to about 3 feet. A flange may extend from the frame and include a notch in which to associate the cradle. The flange may extend in a cantilever fashion from the side frame.  
         [0038]    While the invention herein has been described in the context of a black and white printing machine, it will be readily apparent that the device can be utilized in any analog or digital copying or printing machine in which a fuser is used to bond toner images to a substrate. Moreover, it is evident that many alternatives, modifications, and variations thereof will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications, and variations and their equivalents.