Abstract:
An in situ replacement cartridge ( 200 ) for an electrophotographic printer includes a rigid, cylindrical photoreceptive member ( 206 ); a housing ( 233 ) for retaining and attaching the photoreceptive member to the printer; and a removable shield ( 231   a,    231   b ) surrounding the photoreceptive member.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    Reference is made to commonly-assigned copending U.S. patent application Ser. No. ______ (Attorney Docket No. 96470/NAB), filed herewith, entitled METHOD OF PREVENTING DAMAGE TO A PHOTOCONDUCTOR, by Pitas et al.; the disclosure of which is incorporated herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to electrophotography in general, and in particular to a replacement cartridge for an electrophotographic printer. 
       BACKGROUND OF THE INVENTION 
       [0003]    Electrophotographic equipment utilizes sensitive components that must be routinely serviced by either dedicated service personnel or by the end user. Many of these components are easily damaged unless care is exercised during replacement. In some instances, it is considered imprudent to depend upon an individual exercising care as a step in carrying out critical operation. This is especially important when the risk of error is high, and the cost and machine down-time associated with error is great. 
         [0004]    A primary component requiring frequent replacement within an electrophotographic print engine is the photoreceptive member. The function of the photoconductor is to provide a means of developing an image and transferring that image to paper. The photoreceptive member is coated with photosensitive material which is essential to operation of electrographic printers. The photosensitive material is easily scratched and can be damaged by exposure to ambient light if handled imprudently. This type of damage creates unacceptable image quality defects in the transferred image. 
         [0005]    In close proximity to the receptive member are many components that support the imaging of the photoconductor. These components can scratch or abrade the photoreceptive member during replacement. There is a need to eliminate the potential for damage to the photoreceptive member. 
       SUMMARY OF THE INVENTION 
       [0006]    Briefly, according to one aspect of the present invention an in situ replacement cartridge for an electrophotographic printer includes a rigid, cylindrical photoreceptive member; a housing for retaining and attaching the photoreceptive member to the printer; and a removable shield surrounding the photoreceptive member. 
         [0007]    The invention and its objects and advantages will become more apparent in the detailed description of the preferred embodiment presented below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is an cross-section of a replacement cartridge according to the present invention. 
           [0009]      FIG. 2  is a cross-section of a replacement cartridge in an electrophotographic printer. 
           [0010]      FIG. 3  is a perspective view of the replacement cartridge shown in  FIG. 2   
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    An electrophotographic printer includes all components necessary to accomplish the task of printing an image on paper. A printer is comprised of various subassemblies which perform specific functions. 
         [0012]    An imaging module in the printer consists of components to enable printing of a single color image. Multiple modules may be assembled to enable the printing of multiple color images.  FIG. 1  shows details of a typical printing module  31 , which may be assembled with other imaging modules to enable printing multiple colors. 
         [0013]    Primary charging subsystem  210  uniformly electrostatically charges photoreceptor  206  of photoreceptive member  111 , shown in the form of an imaging cylinder. Charging subsystem  210  may include a grid  213  having a selected voltage, or may be in the form of a roller with conductive properties. 
         [0014]    Additional necessary components provided for control may be assembled around the various process elements of the respective printing modules. Meter  211  measures the uniform electrostatic charge provided by charging subsystem  210 , and meter  212  measures the post-exposure surface potential within a patch area of a latent image formed from time to time in a non-image area on photoreceptive member  206 . 
         [0015]    Image writer  220  is used to expose photoreceptive member  206  and may be a light emitting diode (LED) array or other similar mechanisms or laser. Toning unit  225 , comprising elements  226  and  227  is used to develop the latent image created by image writer  220  on photoreceptive member  206 . Cleaning unit  230  removes residual toner from photoreceptive member  206  after transfer of the image to secondary receiver (not shown). Other meters and components may be included. 
         [0016]    Within the imaging module  31 , periodic replacement of critical components is necessary to ensure proper function. It may be desired to cluster multiple components to enable simultaneous replacement. 
         [0017]    Referring to  FIG. 2 , shown here with a change in form, for the present invention a replacement cartridge  200  within imaging module  31  is created consisting of a photoreceptive member  206 , cleaning unit  230 , and charger  210 . These components are assembled into a cartridge and held in place with a plastic housing  233 . Further, protective guards  231   a  and  231   b  are applied to the module, which serve to prevent damage to the photoreceptive member  206 . The replacement cartridge slides into the electrophotographic printer with guides  232   a  and  232   b.  Guides  232   a  and  232   b  are attached to the printer and help mount and align the replacement cartridge in the proper position. 
         [0018]    Because of the proximity of subsystems that interface with module  31  and with replacement cartridge  200 , it is necessary to have large areas of the photoreceptive member open during use. During insertion into the print engine, these open, unprotected areas could be damaged either mechanically or by light exposure. Therefore it is necessary to protect the photoreceptive member  206  from damage, either from extraneous light, fingerprints, or mechanical scrapes. The protective guards  231   a  and  231   b,  also referred to as a removable shield, slide in place in grooves within the replacement cartridge housing. These removable shields  231   a  and  231   b  stay in place when the cartridge is installed in the printer, and are removed by sliding out of the housing to the front of the equipment after the replacement cartridge  200  is in place in the printer. 
         [0019]    The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the scope of the invention. 
       PARTS LIST 
       [0000]    
       
           31  module 
           111  photoreceptive member 
           200  replacement cartridge 
           206  photoreceptive member 
           210  subsystem 
           211  meter 
           212  meter 
           213  grid 
           220  image writer 
           225  toning unit 
           226  element 
           227  element 
           230  cleaning unit 
           231   a  protective guards (removable shield) 
           231   b  protective guards (removable shield) 
           232   a  guide 
           232   b  guide 
           233  plastic housing