Abstract:
A two part cartridge having a photoconductor part ( 1 ) and a toner part ( 5 ) having no force biasing element on either part. The two parts fit together so that a developer roller ( 7 ) in the toner part contacts a photoconductor drum ( 3 ) in the other part. When the two parts are installed in a printer the cover ( 50 ), when closed, brings a spring ( 62 ) into contact with one side of the toner part while the frame (F) of the printer blocks movement away from the cover. An advantage of the two part cartridge is that the toner part can be replaced without replacing the photoconductor part. Members on the cartridge for force biasing are avoided and the need for training or skill to latch the parts together is avoided.

Description:
RELATED APPLICATION 
   This application is a continuation of U.S. application Ser. No. 10/195,270, filed Jul. 15, 2002 now U.S. Pat. No. 6,678,489, and titled Two Part Cartridges with Force Biasing by Printer. 

   TECHNICAL FIELD 
   This invention relates to electrophotographic imaging and, more particularly, relates to separate replaceable cartridges for toner and photoconductor, which are pressed together for good operation when installed in the imaging device. 
   BACKGROUND OF THE INVENTION 
   Electrophotographic toner cartridges are often joined in two sections pivoted to one another so that a developer roller can be pressed against a photoconductor drum with controlled pressure. The controlled pressure is provided by permanently installed springs stretching between the two sections. The two sections are not normally separated, so such cartridges can be said to be one part cartridges. 
   Such one part cartridges have the advantage of having the spring force installed at the factory manufacturing the cartridge and having a relatively short duration during which the springs need provide the correct pressure, since the entire cartridge is refurbished (or discarded) after use of the original cartridge. Such one-piece cartridges have the disadvantage that the springs must be included on each cartridge. Also, for such one piece cartridges, replacement of the toner with a new section having the toner is not practical since the sections are not readily separated. 
   Two part cartridges are known in which a part having the toner is readily separated from a part having the photoconductor drum, since they are not pivoted to one another. To install such two part cartridges for imaging, they are manually brought together by the operator, and then the operator activates a latching mechanism, such as a resilient latch or a lever of some kind, to force the two parts together with the appropriate pressure for imaging. 
   A disadvantage of such known two part cartridges is that the forcing mechanism must be on one or both of the two parts and therefore adds to supplies costs, as both of the two parts are typically replaceable as they are worn (in the case of the photoconductor and other physical parts) or expended (in the case of the toner). Another disadvantage is that operator involvement requires training or some skill, and requires an overall design which permits the operator to reach the latching mechanism and activate it or deactivate it. A further disadvantage is that the force biasing elements require some space in the body of the imaging devide. 
   DISCLOSURE OF THE INVENTION 
   This invention provides for two part cartridges which have no mechanism to latch the cartridges together. Biasing force during use is provided from the cover of the imaging device when closed. The two parts need only have conforming external configurations so that they fit together, and require no space in the middle of the printer for a force biasing element. No operator involvement in forcing the two parts together is required except for inserting the cartridges in the imaging device and closing the cover of the imaging device. Although the biasing by the cover may be by a spring or springs more costly than springs or other forcing mechanism which might be on the parts, over the life of the imaging device the overall costs typically will be less. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The details of this invention will be described in connection with the accompanying drawings, in which 
       FIG. 1  is a perspective view from the right of the two parts of the cartridge separated; 
       FIG. 2  is a side view from the left with covers removed showing selected parts of the two parts of the cartridge in contact when being forced together by the cover of the printer; 
       FIG. 3  is a side view from the right of the two parts of the cartridge forced together; 
       FIG. 4  is a side view from the left of the two parts of the cartridge separated; 
       FIG. 5  is a side view from the left of the two parts of the cartridge forced together; 
       FIG. 6  is a perspective view from the left showing the inside of the cover of the printer; 
       FIG. 7  is a perspective view of the cover like the view of  FIG. 6  with a housing deleted to fully show the spring mounting; 
       FIG. 8  is a side view from the left sectioned in the middle of the cover showing the cover open and the cartridge parts installed in the printer; and 
       FIG. 9  is a side view as in  FIG. 8  showing part  5  with the cover pivoted to its final position in which it is applying a force by contacting on the toner part of the cartridge. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIG. 1 , a replaceable cartridge part  1  containing a photoconductive drum  3  (shown in  FIG. 2 ) is shown separated from a replaceable cartridge part  5  containing a developer roller  7  and toner (not shown). The right side of part  1  has an upper guide channel  9  ending in a flat section  11  having a rear wall  13 . The right side of part  1  also has a lower guide channel  15 . Planar member  16  is a guide for installation in a printer. 
   The right side of part  5  has an upper guide stud  17  and a lower guide stud  19 .  FIG. 3  shows the two parts  1  and  5  forced together in accordance with this invention. Guide stud  17  fits in channel  9  but does not reach wall  13 . Similarly, guide stud  19  fits in channel  15 . Channels  9  and  15  direct the guide studs  17  and  19  respectively to bring developer roller  7  in contact with photoconductor drum  3  (FIG.  2 ). 
   Part  5  has an upper handle  21 , which can be readily grasped by an operator to pull part  5  away from part  1 . Part  1  has a lower handle  23  which extends past part  5  when the two are combined (FIG.  2 ). Handle  21  and handle  23  can be grasped and pulled by an operator to pull out part  1  and part  5 . 
   Since part  5  contains toner used for imaging, part  5  will be extracted and replaced with a replacement part  5  having toner more frequently than part  1  will be replaced. Part  1  will be extracted and replaced with a replacement part  1  when the photoconductor becomes deteriorated or when excess toner fills the compartment in part  1  for toner cleaned from the photoconductor  3  (such cleaning is standard). 
   Referring to  FIG. 4 , the two parts  1  and  5  are shown from the left side separated. Part  1  has a guide channel  30  ending in a flat section  32  having a rear wall  34 . Part  5  has a guide stud  36 . The cover of part  1  has an opening  38  to provide external access to driven coupling  40  when part  5  is pressed against part  1  (FIG.  5 ). Planar member  42  is a guide for installation in a printer, as is standard. 
   The action of the drive coupling and the gears shown will not be described in detail as they are essentially standard for imaging by driving known parts, not shown, including a toner adder roller and a toner mixing paddle, as well photoconductor drum  3  and the developer roller  7 . Similarly, with reference to  FIG. 2 , spring  46  biasing a change roller  48  against photoconductor  3  is standard and will not be further discussed. 
     FIG. 5  shows parts  1  and  5  from the left forced together in accordance with this invention. Guide stud  36  fits in channel  30  but does not reach wall  34 . Channel  30  directs stud  36  to bring developer roller  7  in contact with photoconductor drum  3  (FIG.  2 ). Driven coupler  40  is located in opening  38  ( FIG. 4 ) for access by a printer drive coupler (not shown). 
   Guide studs  17 ,  19  and  36  are external caps of DELRIN 500 polyacetal, a hard plastic, mounted on shafts integral with the body of part  5 . The body of part  5  is made of polystyrene. Openings  17   a ,  19   a  ( FIG. 1 ) and  36   a ( FIG. 4 ) permit flexing of the shafts. The DELRIN polyacetal caps have a circumferential groove which meshes with small, radial tongues (not shown) extending into the grooves of the caps to thereby form studs  17 ,  19  and  38 . The caps are free to rotate, but they may simply slide without loss of important function with respect to this invention. Alternative materials and construction of studs  17 ,  19  and  36  could be readily employed. 
   Referring to  FIG. 6 , the inside of printer cover  50  is shown, which may be made of a standard, strong plastic. Mounted on opposite sides of cover  50  are pivot arms  52   a  and  52   b , having near their ends pivot studs  54   a  and  54   b . Pivot studs  54   a  and  54   b  enter frame F ( FIG. 8 ) of the printer (only frame of printer illustrated in this description) to define fixed pivot points of cover  50  relative to the frame F. 
   Mounted on the inside of cover  50  is one-piece housing  56 , mounted to cover  50  by four screws,  58   a - 58   d . Housing  56  has latching members  60   a  and  60   b  on opposite sides of cover  50 . Primarily significant to this invention, housing  50  confines a leaf spring  62 , having opposed bent ends  62   a  and  62   b  which extend past housing  56  at openings  56   a  and  56   b  on opposite sides of cover  50 . 
   Housing  56  has integral, upward extending arms  57   a - 57   d , which contact cover extensions  50   a - 50   d . Screws  58   a - 58   d  are located in lateral, oval slots in housing  56 . Integral with housing  56  on the left is a flat, pressing surface or “button”  64 . When cover  50  is closed, latching members  60   a  and  60   b  are pushed leftward by arms  57   a - 57   d  acting on extensions  50   a - 50   d . An operator pushing on button  64  overcomes this force and frees latches  60   a  and  60   b  to allow cover  50  to open. 
     FIG. 7  is the same view as  FIG. 6  with housing  56  and its integral parts deleted so as to better show spring  62  and its mounting. In this embodiment, spring  62  is a single leaf spring held against cover  50  by two screws  70   a ,  70   b  located at the center of spring  62 . Spring  62  is held against undue movement away from cover  50  by spaced ledge members  72   a ,  72   b  on cover  50 . Spring  62  is confined from undue movement laterally by the extensions  72   aa  and  72   bb  holding ledge members  72   a  and  72   b  and by upper and lower spaced ledges  74   a ,  74   aa  and  74   b  and  74   bb . Mounting posts  76   a - 76   d  receive screws  58   a - 58   d  (FIG.  6 ). 
     FIG. 8  shows cover  50  open and the full cartridge of parts  1  and  5  in its installed position on the printer, illustrated as frame elements F. The installed parts are held against further movement away from cover  50  by being blocked by frame F. 
     FIG. 9  omits cartridge part  1  to better illustrate cartridge part  5 . Part  5  is also in the installed position as shown in FIG.  8 . In this position part  1  has a substantially vertical front wall  70 . Upon closing of cover  50 , the ends  62   a  and  62   b  encounter front wall  70  of cartridge part  5  and press it against part  1 . As discussed with respect to  FIG. 8 , the installed cartridge parts  1  and  5  are held against movement away from door  50  by frame members of the printer. Latch members  60   a  and  60   b  flex past ledges (not shown) in the frame F and then latch over the ledges, 
   VARIATIONS AND ALTERNATIVES 
   Although spaced spring contacts as in the foregoing embodiment tend to minimize variations between printers from differences within accepted tolerance, clearly a single leaf spring mounted in the center is an alternative. Of course, two spaced coil springs is an alternative. Other members can provide resilience, such a urethane rubber pads. Instead of spaced contacts, a wide, resilient pad could provide the force biasing. In sum, this invention is not deemed limited by the details of the biasing member operating from the cover. The cover could provide a linkage to move a separated biasing member with movement of the cover, although this normally would be more expensive than simply mounting the biasing member on the cover. 
   A modification of the foregoing under consideration is to replace spring  62  by two, separate leaf springs, each originating near the middle of cover  50  and terminating as shown in the foregoing. 
   Although the cover in the foregoing embodiment opens from the bottom, a clear alternative would be to hinge the cover on the bottom so that it opens from the top. 
   Other variations and alternatives will be readily apparent or can be anticipated.