Abstract:
In a two piece toner cartridge assembly, as typically used in a computer and/or facsimile printing device, comprising separable photoconductor and developer units a unique coupling device is provided whereby the cartridge assembly may be removed from the printing device without the photoconductor unit separating from the developer unit for paper jam clearance or unit replacement. However, if desired the developer unit may be separately removed from the printing device for servicing or replacement without removal of the photoconductor unit.

Description:
TECHNICAL FIELD 
   The present invention generally relates to electrophotographic imaging devices and, more particularly to a two piece printer cartridge assembly having a separately replaceable developer and a photoconductor, which are typically biased together when installed in an imaging device such as a computer printer or facsimile machine. More specifically, the present invention relates to a blocking mechanism whereby the two piece cartridge may be removed as a combined assembly from the imaging device, or the developer unit, having the toner supply therein, may be singly removed for replacement by the user without having to remove the photoconductor. 
   PRIOR ART 
   Heretofore electrophotographic toner cartridges were of the unitary type typically including a developer section and a photoconductor section connected to one another so that the developer roller, of the developer, is pressed against the photoconductor drum, of the photoconductor, with a predetermined and controlled pressure. The controlled pressure is often provided by permanently installed springs stretching between the two units such that the two units are not separable, thereby forming a unitary or one piece replaceable cartridge. 
   Such one piece toner cartridges have the advantage of having the springs installed at the factory manufacturing the cartridge and since the springs have a relatively short operational life, the entire cartridge may be factory refurbished (or discarded) upon depletion of the toner supply whereupon new springs may be installed. However, such one-piece cartridges have the disadvantage that biasing springs must be included in each cartridge assembly thereby increasing the cost of manufacture and/or refurbishing. Also, for such one piece cartridges, replacement, by the user, of the toner section only, with a new toner section, is not practical since the units are not readily separated. 
   However, two piece cartridges are known in which the developer unit, having the toner, is readily separated from the photoconductor unit. When such two piece cartridges are installed in a typical printing device, they are manually brought together, by the user, and interconnected by a latching mechanism, such as a resilient latch, lever, or springs of some sort, whereby the two units are drawn together with the required pressure between the developer roll and the photoconductor roll for satisfactory imaging. 
   A disadvantage of such prior art cartridge assemblies is that the pressure applying mechanism must be installed on one or both of the units and therefore adds to supply costs, as both of the assemblies are typically replaceable as they are worn, as in the case of the photoconductor unit, or expended, as in the case of the developer unit. 
   A further disadvantage of the prior art two piece cartridge, is that such user involvement requires training and/or skill, on the part of the user, and requires an overall structural design which permits the user to easily reach the latching mechanism, between the two units, and activate or deactivate it. A further disadvantage is that the force biasing elements require space within the body of the imaging device. 
   SUMMARY OF THE INVENTION 
   The present invention provides for an easily separated two piece toner cartridge assembly, comprising a developer unit and a photoconductor unit which requires no force biasing mechanism between the developer unit and the photoconductor unit. The biasing force mechanism urging the developer unit and the photoconductor units together, with the desired pressure for use, is provided by the front cover of the imaging device, within which the toner cartridge is inserted, when the front cover, of the imaging device, is in the closed operational position. The developer and photoconductor units need only have conforming external configurations wherein they fit together requiring no interior space within the imaging device for accommodating a force biasing mechanism to urge the developer and photoconductor units together. No user involvement is necessary for urging the developer and photoconductor units together except for inserting the units into the imaging device and closing the cover of the imaging device. Although the biasing mechanism provided by the cover may comprise a spring or springs more costly than springs or other forcing mechanism which might be otherwise provided between the developer unit and the photoconductor unit, over the life of the imaging device the overall costs will typically be less. 
   A novel feature of the two piece toner cartridge taught herein comprises a blocking mechanism whereby the developer unit and the photoconductor unit may be locked together and removed from the imaging device as a unitary assembly or the developing unit may be unlocked from the photoconductor unit and singly removed from the imaging device for servicing or replacement. A blocking lever is provided within the handle of the photoconductor unit which, although not being in a physical latched relationship with the developer unit, nevertheless functions as a physical obstructing barrier preventing separation of the developer unit from the photoconductor unit when the blocking lever is in the blocking position thereby allowing removable of the photoconductor unit from the imaging device with the developer unit intact. To separate the developer unit from the photoconductor unit, the blocking lever is repositioned to an unlocked position, thereby permitting the developer unit to be separated from the photoconductor unit. 
   Thus by the present invention, a two piece toner cartridge may be removed from an imaging device and handled as a unitary assembly, or the two units may be easily separated from one another for separate servicing. 

   
     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 showing the two piece toner cartridge having the developer unit separated from the photoconductor unit in accord with the present invention. 
       FIG. 2  is a perspective view of the two piece toner cartridge having the photoconductor unit and the developer unit assembled in accord with the present invention. 
       FIG. 3  is a left side view with covers removed, showing selected elements of the photoconductor and developer units of the two piece toner cartridge as an operating assembly with the blocking arms in their default, locked position. 
       FIG. 4  is a left side view showing the photoconductor and developer units separated from one another. 
       FIG. 5  is a left side view of the photoconductor and developer units assembled in accord with the present invention. 
       FIG. 6  is a reverse angle perspective view of  FIG. 2  showing the photoconductor and developer units assembled in accord with the present invention. 
       FIG. 7  is a perspective view of the photoconductor unit separated from the developer unit. 
       FIG. 8  is a sectional view taken along line  8 — 8  in FIG.  7 . 
       FIG. 8A  is a partial schematic view of a typical method of attaching the unit blocking assembly to the photoconductor unit handle. 
       FIG. 9  presents a perspective view of the unit blocking assembly removed from the photoconductor handle. 
       FIG. 10  is a partial left side view showing the blocking arms in their release position. 
       FIG. 11  is a left side view, similar to  FIG. 3 , showing the developer unit being removed from the photoconductor unit. 
       FIG. 12  is a perspective view showing the inside of the printer front cover. 
       FIG. 13  is a perspective view of the printer front cover, similar to the view in  FIG. 12 , with a housing deleted to fully show the pressure spring mounting. 
       FIG. 14  is a left side view showing the printer cover, sectioned in the middle, illustrating the cover in the open position and the assembled toner cartridge as installed in a typical printer. 
       FIG. 15  presents a left side view, similar to that in  FIG. 14 , showing the printer cover pivoted to its final closed and operating position wherein the cover is applying a lateral force upon the developer unit thereby biasing the developer and photoconductor units together in accord with the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 , presents a pictorial view of a two piece cartridge assembly illustrating the developer unit  5  separated from the photoconductor unit  1 . Developer unit  5  includes the developer roller  7  and toner (not shown). The right side of photoconductor unit  1  includes an upper guide channel  9  ending in a flat section  11  having a rear wall  13 . The right side of photoconductor unit  1  also includes a similar, lower guide channel  15 . Planar member  16  is a guide for installation of photoconductor unit  1  within a printer. Similarly the left side of photoconductor unit  1  includes an upper guide channel  30  and a lower guide channel  31 . 
   The right side of developer unit  5  includes an upper guide stud  17  and a lower guide stud  19 . Similarly the left side of developer unit  5  includes an upper guide stud  36  and a lower guide stud  35  as best illustrated in FIG.  4 .  FIG. 2  illustrates the photoconductor unit  1  and the developer unit  5  assembled in their normal working configuration. Guide stud  17  fits within channel  9  but does not reach wall  13 . Similarly, guide studs  19 ,  35  and  36  fit within channels  15 ,  31  and  30  respectively. Thus channels  9 ,  15 ,  30  and  31  engage guide studs  17 ,  19 ,  36  and  35  respectively, (see  FIGS. 2 ,  5 , and  5   a ) thereby bringing developer roller  7  into an aligned contact with photoconductor drum  3  as illustrated in FIG.  3 . 
   Developer unit  5  also includes an upper handle  21 , which can be readily grasped by the user to separately remove developer unit  5  from engagement with photoconductor unit  1 . Photoconductor unit  1  is also provided with a lower handle  23  which extends slightly beyond developer unit  5  when the two units are combined as illustrated in  FIGS. 3 ,  5  and  6 . Included within handle  23  is a blocking mechanism  80 , as illustrated in  FIGS. 8 and 9  whereby developer unit  5  is blockingly restrained within photoconductor unit  1 . Thus handle  23 , or handle  21 , may be grasped by the user to remove the photoconductor unit  1  and developer unit  5 , as a coupled assembly, (see  FIG. 6 ) from the printer device, without the developer unit separating from the photoconductor unit. 
   Turning now to  FIGS. 7 ,  8 ,  8 A and  9 , blocking mechanism  80  is included within photoconductor handle  23  comprising an elongated torsion rod  82  having journal ends  84   a  and  84   b  at opposites ends thereof. Integral with rod  82  and positioned inward from journals  84   a  and  84   b  are radially extending blocking arms  86   a  and  86   b.    
   Journal ends  84   a  and  84   b  are rotatingly received within a pair of laterally opposed, over center, “C” shaped receptacles  87 , integrally molded into the structure of handle  23  as illustrated in  FIG. 8A , or any other suitable receptacle mounting within which rod  82  may freely rotate. Affixed to torsion rod  82  is an offset toggle button  85  for manually rotating torsion rod  82 . Torsion spring  89  is attached to at least one of the blocking arms  86  such that the blocking mechanism  80  is biased to the default blocking position as illustrated in FIG.  3 . Upon depressing button  85 , torsion rod  82  will rotate counterclockwise, as indicated by arrow A in  FIG. 9 , thereby rotating blocking arms  86  downward as illustrated in FIG.  10 . 
   When blocking arms  86  are in their default, blocking position, as illustrated in  FIG. 3 , there is a small clearance, or gap, provided between blocking arms  86  and the bottom edge  93  of developer unit  5  such that in an attempt to remove developer unit  5  from photoconductor unit  1 , bottom edge  93 , of developer unit  5 , will physically contact blocking arms  86  thereby preventing separation of developer unit  5  from photoconductor unit  1 . 
   The physical contact between bottom edge  93  and blocking arms  86  is assured by the movement of guide studs  17 ,  19 ,  35  and  36  within their respective guide channels  9 ,  15 ,  31 , and  30 . In order to remove developer unit  5  from photoconductor unit  1 , developer unit  5  must, by action of the guide channels, first translate horizontally before it can move upward and away from the photoconductor unit as illustrated in FIG.  11 . Thus when blocking arms  86  are in their default blocking position,  FIG. 3 , developer unit  5  may not be separated from photoconductor unit  1 . 
   However, when blocking arms  86  are rotated downward, by the operator depressing toggle button  85 , blocking arms  86  are removed from the path of bottom edge  93 , as illustrated in  FIG. 10  thereby permitting passage of bottom edge  93  and removal of developer unit  5  from photoconductor unit  1  as illustrated in FIG.  11 . Accordingly handle  21  is used to remove both units  1  and  5  together and by rotating blocking arm  86  downward, to remove unit  5  alone. Handle  23  on unit  1  is used only rarely, when unit  1  is replaced or discarded. 
   Since developer unit  5  contains the toner used for imaging, the developer unit will be removed and replaced with a replacement developer unit more frequently than photoconductor unit  1 . Photoconductor unit  1  will only be removed and replaced when the photoconductor unit becomes deteriorated or when the photoconductor unit&#39;s waste toner sump is judged to be full. 
   Referring to  FIG. 4 , units  1  and  5 , are shown from the left side and separated. Photoconductor unit  1  includes a guide channels  30  and  31  ending in a flat section  32  and  33  and having a rear wall  34  and  37 . Developer unit  5  includes a guide studs  36  and  35 . The side wall of photoconductor unit  1  includes an opening  38  to provide external access to driven coupling  40  when developer unit  5  is installed within photoconductor unit  1  (See FIG.  5 ). 
     FIG. 5  illustrates units  1  and  5 , as viewed from the left side, assembled in accordance with the present invention. Guide stud  36  is received in channel  30  but does not reach wall  34 . Similarly guide stud  35  is received in channel  31  but does not reach wall  37 . When assembled, as illustrated in  FIGS. 2 and 5 , channels  30 ,  31 ,  15 , and  9  act to direct studs  36 ,  19 ,  17 , and  35  respectively, thereby bringing developer roller  7  into aligned contact with photoconductor drum  3  (See FIG.  3 ). When units  1  and  5  are assembled as illustrated, in  FIGS. 2 and 5 , driven coupler  40  is aligned with opening  38  for access by a printer driving coupler (not shown). 
   The action of the drive coupling and the gears shown in  FIGS. 3 and 4 , will not be described in detail as they are essentially standard for imaging apparatus and drive known elements, not shown, including a toner, an adder roller and a toner mixing paddle, as well as the photoconductor drum  3  and developer roller  7 . Similarly, with reference to  FIG. 3 , spring  46  biasing charge roller  48  against photoconductor  3  is standard and will not be further discussed. 
   Guide studs  17 ,  19 ,  35  and  36  preferably include external caps of polyacetal, a hard plastic, mounted on shafts integral with the body of developer unit  5 . The body of developer unit  5  is preferably made of polystyrene. 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 ,  35  and  36 . The polyacetal 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 ,  35  and  36  could be readily employed by one skilled in this technology. 
   Referring now to  FIG. 12 , the inside of printer cover  50  is illustrated, which may be made of any suitable, 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 (See  FIG. 12 ) of the printer structure (not shown) to define fixed pivot points for cover  50  relative to the frame F. 
   Mounted on the inside of cover  50  is one-piece housing  56 , attached to cover  50  by four screws,  58   a ,  58   b ,  58   c  and  58   d . Housing  56  includes 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  includes integral, upward extending arms  56   a ,  56   b ,  56   c , and  56   d  (see  FIG. 12 ) which contact cover extensions  50   a ,  50   b ,  50   c , and  50   d . Screws  58   a ,  58   b ,  58   c , and  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  56   a ,  56   b ,  56   c , and  56   d  acting on extensions  50   a ,  50   b ,  50   c , and  50   d . A user pushing on button  64  overcomes this force and frees latches  60   a  and  60   b  to allow cover  50  to be opened. 
     FIG. 13  presents a similar view as that in  FIG. 12  with housing  56  and its integral assemblies deleted so as to better illustrate spring  62  and its mounting. In the embodiment illustrated in  FIG. 13 , spring  62 , a single leaf spring, is attached to 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 lateral movement by 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   b ,  58   c , and  58   d  (See FIG.  13 ). 
   Referring now to  FIG. 14 , printer cover  50  is illustrated in an open position with the cartridge assembly, comprising developer unit  5  and photoconductor unit  1 , in its installed position within the printer. The printer structure is illustrated as frame elements F. The installed photoconductor unit  1  and developer unit  5  are held in place and prevented from moving away from cover  50  by action of frame F. 
   In  FIG. 15  cartridge photoconductor unit  1  has been removed to better illustrate developer unit  5  and its interaction with cover  50  and is illustrated in its installed position. As illustrated in  FIG. 15  developer unit  5  has a substantially vertical front wall  70 . Upon closing cover  50 , the ends  62   a  and  62   b  encounter front wall  70  of cartridge developer unit  5  thereby applying pressure against wall  70  urging developer unit  5  against photoconductor unit  1 . Thus the installed units  1  and  5  are held against movement away from door  50  by frame members F of the printer. Latch members  60   a  and  60   b  (See  FIG. 12 ) flex past ledges (not shown) in the printer frame F and latch over the ledges thereby securing cover  50  to the printer frame. 
   VARIATIONS AND ALTERNATIVES 
   Although a specific embodiment of the invention has been disclosed, there is no intent to thereby limit the invention to the specific embodiment illustrated herein. On the contrary, the intention herein is to cover all modifications, alternatives, embodiments, usage and/or equivalents of the subject invention as may fall within the spirit and scope of the invention as disclosed. Accordingly, the scope of the present invention is to be considered in terms of the following claims and understood not to be limited to the details of the structures and methods shown and described in the specification and drawings.