Image forming apparatus having rotatable electrophotographic process unit

Abstract

An image forming apparatus has two units which are engageable with a photoconductive element and provided with a substantially identical configuration. Various electrophotographic process devices including a developing device and a cleaning device and to be arranged around the photoconductive element are selectively arranged in the two units. The photoconductive element is passed over two rollers such that part of the element forms parallel flat portions. The two units and the photoconductive element are rotatable integrally with each other.

What is claimed is: 
     
       1. An image forming apparatus comprising: an image carrier; and   a plurality of electrophotographic process means arranged around said image carrier;   at least part of said plurality of electrophotographic process means being constructed into two units each being engageable with said image carrier and rotatable integrally with said image carrier, such that said image carrier and said two units are rotatable together as a unit;   said two units having a substantially identical configuration, and wherein said two units are shaped and positioned such that as said image carrier and said two units rotate together each of said two units are disposed inside of a locus of rotation of said image carrier, and wherein said locus of rotation is defined as a path of radially outermost points of said image carrier as said image carrier and said two units rotate together.   
     
     
       2. An apparatus as claimed in claim 1, wherein one of said units comprises any of said electrophotographic process means whose life is comparatively long, the other of said units comprising any of said process means whose life is comparatively short. 
     
     
       3. An image forming apparatus comprising: an image carrier; and   a plurality of electrophotographic process means;.   at least part of said plurality of electrophotographic process means being constructed into two units each being engageable with said image carrier and rotatable integrally with said image carrier, such that said image carrier and said two units are rotatable together as a unit;   said two units having a substantially identical configuration;   wherein one of said two units comprises any of said electrophotographic process means whose life is comparatively long, the other of said two units comprising any of said process means whose life is comparatively short; and   wherein said electrophotographic process means whose life is comparatively long comprises a developing device while said electrophotographic process means whose life is comparatively short comprises a cleaning device.   
     
     
       4. An apparatus as claimed in claim 1, wherein said unit includes a flat portion and said two units are each constructed such that said electrophotographic process means received therein does not protrude from the flat portion included in said unit. 
     
     
       5. An apparatus as claimed in claim 4, further comprising a cylindrical receptacle for storing said two units removed from a body of said apparatus. 
     
     
       6. An image forming apparatus comprising: an image carrier; and   a plurality of electrophotographic process means;   at least part of said plurality of electrophotographic process means being constructed into two units each being engageable with said image carrier and rotatable integrally with said image carrier, such that said image carrier and said two units are rotatable together as a unit;   said two units having a substantially identical configuration;   wherein one of said two units comprises any of said electrophotographic process means whose life is comparatively long, the other of said two units comprising any of said process means whose life is comparatively short; and   wherein a body of said apparatus comprises a housing through which an opening is formed, said opening allowing only one of said two units to pass therethrough into or out of said body at a time.   
     
     
       7. An apparatus as claimed in claim 6, wherein said other of said two units comprises said electrophotographic process means whose life is comparatively short and is positioned closest to said opening. 
     
     
       8. An apparatus as claimed in claim 6, wherein said opening is oriented such that said two units are each inserted or pulled out with a portion thereof engageable with said image carrier facing upward. 
     
     
       9. An image forming apparatus comprising: an image carrier; and   a plurality of electrophotographic process means;   at least part of said plurality of electrophotographic process means being constructed into two units each being engageable with said image carrier and rotatable integrally with said image carrier, such that said image carrier and said two units are rotatable together as a unit;   said image carrier being implemented as an endless belt and passed over two rotatable support means such that part of said belt forms two flat portions, said electrophotographic process means of said two units being arranged in such a manner as to face said flat portions of said belt respectively;   said two units each comprising a casing, the outer periphery of said casing forming, when each of said two units is engaged with said image carrier, part of a circumcircle of said image carrier.   
     
     
       10. An apparatus as claimed in claim 9, wherein said electrophotographic process means of said two units which face said flat portions of said image carrier comprise a developing device and cleaning device, respectively. 
     
     
       11. An apparatus as claimed in claim 10, wherein said developing device and said cleaning device are respectively accommodated in said two units and each faces a respective one of said flat portions of said image carrier. 
     
     
       12. An image forming apparatus comprising: an image carrier;   a plurality of electrophotographic process means;   at least part of said plurality of electrophotographic process means being constructed into two units each being engageable with said image carrier and rotatable integrally with said image carrier, such that said image carrier and said two units are rotatable together as a unit; and   discriminating means for determining at least one of: (1) a kind of each of said two units; and (2) a position of each of said two units.     
     
     
       13. An apparatus as claimed in claim 12, wherein said discriminating means comprises a plurality of conductive contact pieces provided in spaced positions on an outer periphery of each of said two units, and a plurality of conductive terminals mounted on a body of said apparatus for contacting said conductive contact pieces. 
     
     
       14. An apparatus as claimed in claim 12, wherein each of said two units includes a front end plate and wherein said discriminating means comprises a projection extending out from the front end plate of each of said two units and protruding from a front edge of an inlet formed in a mounting portion of a body of said apparatus. 
     
     
       15. An apparatus as claimed in claim 12, wherein said discriminating means comprises a cross-sectional area which decreases from a front portion to a rear portion of each of said two units, a mounting portion of a body of said apparatus including a portion whose cross-sectional area is smaller than the cross-sectional area of said front portions of said two units. 
     
     
       16. An apparatus as claimed in claim 15, wherein said front portion comprises an inlet. 
     
     
       17. An apparatus as claimed in claim 15, wherein said front portion comprises handle means provided on an end face of said front portion. 
     
     
       18. An image forming apparatus comprising: an image carrier;   a plurality of electrophotographic process means; and   at least part of said plurality of electrophotographic process means being constructed into two units each being engageable with said image carrier and rotatable integrally with said image carrier, such that said image carrier and said two units are rotatable together as a unit;   handle means provided on an outer periphery of each said two units to be selectively raised or lowered and, when raised, having support portions thereof lying in a vertical plane containing a center of gravity of said unit.   
     
     
       19. An image forming apparatus comprising: an image carrier; and   a plurality of electrophotographic process means;   at least part of said plurality of electrophotographic process means being constructed into two units each being engageable with said image carrier and rotatable integrally with said image carrier, such that the integral arrangement itself having said image carrier and said two units are bodily rotatable together as a unit about an axis in a body of said image forming apparatus;   wherein said two units comprise respective casings having a substantially identical configuration, said casings each being formed with a notch at a particular position, a body of said apparatus comprising a housing through which an opening capable of passing only one of said casings at a time is formed and an engaging member which mates with said notch when one of said casings is mounted or dismounted.   
     
     
       20. An image forming apparatus comprising: an image carrier; and   a plurality of electrophotographic process means;   at least part of said plurality of electrophotographic process means being constructed into two units each being engageable with said image carrier and rotatable integrally with said image carrier, such that the integral arrangement itself having said image carrier and said two units are bodily rotatable together as a unit about an axis in a body of said image forming apparatus;   the apparatus further comprising display means, and discriminating means for determining a kind of said two units being mounted, said display means displaying a guidance matching the kind of said two units.   
     
     
       21. An apparatus as claimed in claim 20, wherein said discriminating means is mounted on a body of said apparatus and determines the kind of each of said two units when said discriminating means contacts part of each of said two units. 
     
     
       22. An apparatus as claimed in claim 20, wherein said discriminating means comprises transmitting means mounted on each of said two units for transporting a particular signal, and receiving means mounted on a body of said apparatus for receiving said signal from each of said two units. 
     
     
       23. An apparatus as claimed in claim 22, wherein said two units each comprise a switch to be operated when an operator holds a handle provided on each of said two units for inserting said two units into a body of said apparatus, said transmitting means transmitting said signal when said switch is closed. 
     
     
       24. An apparatus as claimed in claim 20, wherein said two units each include a particular color representative of the kind of each of said two units, said display means displaying the kind of each of said two units by using the same respective colors as said two units. 
     
     
       25. An apparatus as claimed in claim 20, wherein when one of said two units is inserted into a body of said apparatus, said display means displays an error when said one of said two units being inserted is of the same kind as another of said two units already mounted on said body as determined by said discriminating means. 
     
     
       26. An apparatus as claimed in claim 20, wherein said display means displays the kind of one of said two units which is not mounted as determined by said discriminating means. 
     
     
       27. An apparatus as claimed in claim 25, wherein said display means is positioned in close proximity to an opening which is formed through said body of said apparatus for inserting and removing said two units. 
     
     
       28. An image forming apparatus comprising: an image carrier; and   a plurality of electrophotographic process means;   at least part of said plurality of electrophotographic process means being constructed into two units each being engageable with said image carrier and rotatable integrally with said image carrier, such that the integral arrangement itself having said image carrier and said two units are bodily rotatable together as a unit about an axis in a body of said image forming apparatus;   the apparatus further comprising detecting means for detecting a paper jam occurring in a transport path, and control means for controlling the operation of said apparatus such that when said detecting means detects a paper jam, said two units are moved away from said image carrier.   
     
     
       29. An apparatus as claimed in claim 28, wherein said control means controls said apparatus such that when said detecting means detects a paper jam occurred at a toner image transfer position, said image carrier is fixed in an image forming position. 
     
     
       30. An apparatus as claimed in claim 28, wherein said control means control said apparatus such that when said detecting means detects a paper jam at a toner image transfer position, image transferring means and devices associated therewith are moved away from said image carrier. 
     
     
       31. An image forming apparatus comprising: an image carrier; and   a plurality of electrophotographic process means;   at least part of said plurality of electrophotographic process means being constructed into two units each being engageable with said image carrier and rotatable integrally with said image carrier, such that the integral arrangement itself having said image carrier and said two units are bodily rotatable together as a unit about an axis in a body of said image forming apparatus;   the apparatus further comprising:   support means for supporting said two units and said image carrier such that said two units and said image carrier are rotatable integrally;   first detecting means for detecting an end of a rotary motion of said two units and said image carrier;   second detecting means for detecting that said two units are mounted on a body of said apparatus; and   means for causing, among said plurality of electrophotographic process means, a cleaning device to operate and for rotating said image carrier in response to detection outputs of said first and second detecting means.   
     
     
       32. An image forming apparatus comprising: an image carrier; and   a plurality of electrophotographic process means arranged around said image carrier,   at least part of said plurality of electrophotographic process means being constructed into two units each being engageable with said image carrier and rotatable integrally with said image carrier, such that the integral arrangement itself including said image carrier and said two units are bodily rotatable together as a unit about an axis in a body of said image forming apparatus, wherein a closed space is defined within said image carrier, and said axis is located in said closed space;   the apparatus further including first support means for supporting said two units and said image carrier such that said two units and said image carrier are rotatable integrally;   second support means for supporting said two units such that said two units each move into or out of contact with said image carrier in interlocked relation to the rotation of said two units and said image carrier; and   said second support means causing said two units to move away from said image carrier only at a position where said two units may be mounted or dismounted.   
     
     
       33. An apparatus as set forth in claim 28, wherein said control means further controls said apparatus such that when said detecting means detects a paper jam on said transport path at a position other than a toner image transfer position, said two units are rotated together with said image carrier to move portions of said image carrier which are exposed away from said transport path. 
     
     
       34. An image forming apparatus comprising: an image carrier; and   a plurality of electrophotographic process means arranged around said image carrier;   at least part of said plurality of electrophotographic process means being constructed into two units each being engageable with said image carrier and rotatable integrally with said image carrier, such that the integral arrangement itself including said image carrier and said two units are bodily rotatable together as a unit about an axis in a body of said image forming apparatus, wherein a closed space is defined within said image carrier, and said axis is located in said closed space, and further wherein said two units comprise a developing unit and a cleaning unit.   
     
     
       35. An image forming apparatus comprising: an image carrier;   a plurality of electrophotographic process means arranged around said image carrier;   at least part of said plurality of electrophotographic process means being constructed into two units each being engageable with said image carrier and rotatable integrally with said image carrier, such that the integral arrangement itself including said image carrier and said two units are bodily rotatable together as a unit about an axis in a body of said image forming apparatus, wherein each of said two units include a contour which coincides with a locus of rotation of the image carrier, and wherein said locus of rotation is defined as a path of radially outermost points of said image carrier as said image carrier and said two units rotate together. .Iadd.   
     
     
       36.  An image forming apparatus for forming a toner image on an image forming medium, comprising: an outer housing which has an opening; and   a plurality of image forming units for forming said toner image on said image forming medium,   predetermined image forming units, each having a life which is shorter than that of said apparatus, among said plurality of image forming units being formed as a cylindrically shaped unit which rotates around a center of said cylindrically shaped unit, one of said predetermined image forming units being removed from said image forming apparatus when said predetermined image forming unit faces to said housing. .Iaddend..Iadd.37. An image forming apparatus as claimed in claim 36, wherein said one of said predetermined image forming units comprises a developing unit having a developing roller which is covered when said developing unit faces to   
     
     
        said opening. .Iaddend..Iadd.38.  An image forming apparatus comprising: a housing;   an image carrier in said housing;   at least one image developing device rotatable mountable in said housing; and   an opening in a wall of said housing, said opening being generally aligned with said developing device when said developing device is mounted in said housing at a predetermined rotational position,   wherein said developing device is mounted in said housing such that said developing device may be introduced and removed from said housing through said opening when said developing device is at said predetermined   
     
     
        rotational position. .Iaddend..Iadd.39.  The image forming apparatus of claim 38 including a generally cylindrical unit mounted for rotation in said housing about a cylinder axis thereof, said generally cylindrical unit having said at least one image developing device, wherein said at least one image developing device is mounted for rotation about the cylinder axis of said unit. .Iaddend..Iadd.40. The image forming apparatus of claim 38 wherein said opening has a size and shape which is substantially the same as a size and shape of said developing device. .Iaddend..Iadd.41. The image forming apparatus of claim 39 wherein said opening has a size and shape which is substantially the same as a size and shape of said developing device. .Iaddend..Iadd.42. The image forming apparatus of claim 38 including discriminating means for discriminating an identifying characteristic of said image developing device. .Iaddend..Iadd.43. The image forming apparatus of claim 38 including at least one image processing device which is outside a locus of revolution of said image developing device. .Iaddend..Iadd.44. The image forming apparatus of claim 38 wherein said housing includes an element which mates with the developing device only when the developing device is correctly 
     
     
        mounted in said housing. .Iaddend..Iadd.45.  The image forming apparatus of claim 38 including means for displaying that the developing device is empty. .Iaddend..Iadd.46. The image forming apparatus of claim 38, wherein said developing device cooperates with said image carrier to develop an image on said image carrier when said developing device is in a developing position which is different from said predetermined rotational position. .Iaddend..Iadd.47. The image forming apparatus of claim 38 including means for shutting off electrical power to said developing device when said developing device is at said predetermined position. .Iaddend..Iadd.48. The image forming apparatus of claim 38 wherein said image developing device includes a developing roller which cooperates with said image carrier to develop an image on said image carrier. .Iaddend..Iadd.49. The image forming apparatus of claim 39 wherein said image developing device includes a developing roller which cooperates with said image carrier to develop an image on said image carrier. .Iaddend..Iadd.50. The image forming apparatus of claim 48 wherein said developing device includes an opening through which said developing roller is exposed so as to cooperate with said image carrier, further including a shutter which selectively closes said opening. .Iaddend..Iadd.51. The image forming apparatus of claim 49 wherein said developing device includes an opening through which said developing roller is exposed so as to cooperate with said image carrier, further including a shutter which selectively closes said opening. .Iaddend.