Abstract:
A waste collection tube for a dry electrophotographic printer is a molded, open construction. The molded open construction has mirror symmetry, and a first half and a second half connected by a flexible hinge. The first half and the second half open construction waste tubes have edges and labyrinth seals on the edges. A fastening device attaches the first half to the second half in a removable manner.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    Reference is made to commonly-assigned copending U.S. patent application Ser. No. ______ (Attorney Docket No. 96593/NAB), filed herewith, entitled METHOD FOR MAKING WASTE COLLECTION TUBE, 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 method of making a waste collection tube for an electrophotographic printer. 
       BACKGROUND OF THE INVENTION 
       [0003]    The electrophotographic process creates an image on paper or other suitable printing media. An electrophotographic printer is comprised of components assembled into a print engine. 
         [0004]    The primary material used for printing purposes is toner. During the printing process not all of the toner transfers to the print media. Some of this toner may be unsuitable for transfer, but is present in the toner supply, or some of the toner may be intended to be discarded as part of the normal process. When this residual material is produced it is necessary to transport the material to a collection point. A waste transport device is used for this purpose. Sealing of the waste transport device is critical to prevent leakage and subsequent contamination of the machine. 
         [0005]    A primary component of a waste transport device is the waste collection tube. Manufacturers glue or ultrasonically weld the parts of the waste collection tube together. This process is labor intensive, expensive, and prone to leakage if the attachment is imperfect. 
         [0006]    Some manufacturers make collection tubes in two parts and then glue or ultrasonically weld the parts together. Great care must be taken to ensure that leakage does not occur. Often tube joints need to be wrapped or otherwise have the seals reinforced to prevent leakage. 
       SUMMARY OF THE INVENTION 
       [0007]    Briefly, according to one aspect of the present invention a waste collection tube for a dry electrophotographic printer is a molded, open construction. The molded open construction has mirror symmetry, and a first half and a second half connected by a flexible hinge. The first half and the second half open construction waste tubes have edges and labyrinth seals on the edges. A fastening device attaches the first half to the second half in a removable manner. 
         [0008]    In the present invention, the two halves of the waste collection tube are attached to each other by a “living hinge” that allows them to flex together during construction and assembly. The flexible seam or hinge is located at the bottom of the assembly in an auger cavity which is the area that is most prone to leakage. 
         [0009]    The hinge is made by molding the two halves of the assembly as one flexible piece, using a plastic or similar material. The joint between the two parts is sufficiently thin so as to allow the joint to flex without cracking Having the living hinge in the portion of the cavity where leakage would be most likely to occur is unique and produces unexpected results. This method eliminates tooling required in more commonly practiced sealing techniques. For example, specifically designed ultrasonic horns or gluing fixtures are not needed when practicing the present invention. 
         [0010]    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 
         [0011]      FIG. 1  is a cross-section of an electrophotographic print module. 
           [0012]      FIG. 2  is a cross-section of an electrophotographic print module cartridge with interface hardware. 
           [0013]      FIG. 3  is a waste transport device. 
           [0014]      FIG. 4  is a waste transport device with internal detail. 
           [0015]      FIG. 5  is a waste transport device showing assembly process. 
           [0016]      FIG. 6  is a waste transport device showing assembly process. 
           [0017]      FIG. 7  is a waste transport device showing assembly process. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    The present invention will be directed in particular to elements forming part of, or in cooperation more directly with the apparatus in accordance with the present invention. It is to be understood that elements not specifically shown or described may take various forms well known to those skilled in the art. 
         [0019]    Referring now to  FIG. 1 , an electrophotographic printer includes components necessary to print an image on paper. A printer is comprised of various sub-assemblies which perform specific functions. 
         [0020]    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. 
         [0021]    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. 
         [0022]    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 photoreceptor  206 . 
         [0023]    Image writer  220  is used to expose photoreceptor  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 photoreceptor  206 . Cleaning unit  230  removes residual toner from photoreceptor  206  after transfer of the image to a secondary receiver. Other meters and components may be included. 
         [0024]    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. 
         [0025]    Referring to  FIG. 2 , shown here with a change in form, is one such cluster, referred to as a replacement cartridge  200  within imaging module  31  consisting of a photoreceptive member  111 , cleaning system  230 , and charging subsystem  210 . These components are assembled into a cartridge and held in place with a plastic housing  233 . 
         [0026]    Referring now to  FIG. 3  a waste transport device  260  is shown. The waste transport device consists of collection tube  261  and transport tube  262 . Residual toner waste from cleaning unit  230  and toning unit  225  leave those devices and drop into the waste transport device at points A and B. The waste transport device  260  collects and combines the residual waste toner into a common waste stream which exits the waste transport device  260  at point C. Referring now to  FIG. 4 , within the transport tube  262  is a screw auger  263  which turns through the use of a drive device  264 . The drive device  264  may take many forms, either through direct coupling, or with a belt drive or gear drive arrangement. The drive turns the screw auger  263  and transports the residual toner waste to a convenient collection point C. The screw auger  263  may or may not enter a waste collection bottle at point C. 
         [0027]    Referring now to  FIGS. 5-7  shows a means of construction of the waste transport device  260  with the final step shown in  FIG. 3 . The waste collection device must be sealed to prevent contamination escaping and entering the print engine. The critical location for leakage is at the base of the transport tube, which through gravity and transport of the toner by screw auger  263 , tends to open the assembly joint and contaminate the print engine. The design of the waste tube integrates a living hinge along a long length of the transport tube  262  which creates an intrinsic seal when assembled. The hinged edge must be flexible in order to fold during assembly without fracturing. Typical materials chosen for such applications are polyethylene, polypropylene, polystyrene, or polyester. 
         [0028]    The design of the device is such that the long length is created substantially vertical at the base of the transport tube, which is the most critical point for leakage. Other less critical joints are created with overlapping plastic labyrinth features to seal, and snap features or fasteners to retain the assembly. As leakage possibility in these other locations is far less likely, less positive sealing means are required. 
         [0029]    Such a waste transport device depends upon additional parts for the transport of toner. Typically components included in the assembly include an auger, rattlers, bearing, springs, gates, shut off, or combinations thereof. 
         [0030]    Alignment features are included in the first half of the transport tube such that components are easily inserted in the first half of the open construction prior to joining the first half to the second half. The flexible hinge along the long length of the tube aids assembly by providing precise alignment when folded. 
         [0031]    Other designs in similar electrophotographic equipment comprise two separate pieces with glued, ultrasonically welded or screwed construction with sealing tapes. Assembly of the tube and various components within requires precise locating techniques. The construction of the waste collection device outlined is less costly than traditional two piece constructions and offers ease of disassembly for reuse purposes. 
         [0032]    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  printing module 
               111  photoreceptive member 
               200  replacement cartridge 
               206  photoreceptor 
               210  charging subsystem 
               211  meter 
               212  meter 
               213  grid 
               220  image writer 
               225  toning unit 
               226  element 
               227  element 
               230  cleaning unit 
               233  plastic housing 
               260  waste transport device 
               261  collection tube 
               262  transport tube 
               263  screw auger 
               264  drive device