Image forming apparatus and image forming unit detachably mountable thereto

Abstract

An image forming unit detachably mountable to an image forming apparatus includes an image bearing member, and an intermediate transfer member to which a toner image on the image bearing member is transferred, the image bearing member and the intermediate transfer member being movable relative to each other in the image forming unit.

What is claimed is:  
     
         1 . An image forming unit detachably mountable to an image forming apparatus, said image forming unit comprising: 
 an image bearing member; and    an intermediate transfer member to which a toner image on said image bearing member is transferred,    wherein said image bearing member and said intermediate transfer member are movable relative to each other in said image forming unit.    
     
     
         2 . An image forming unit according to  claim 1 , wherein said image forming unit is mounted to a main body of the image forming apparatus, whereby positions of said image bearing member and said intermediate transfer member relative to the main body of the apparatus are determined.  
     
     
         3 . An image forming unit according to  claim 2 , further comprising: 
 a fixed projected portion;    a driving bearing portion of said image bearing member; and    a driving bearing portion of said intermediate transfer member,    wherein said image forming unit is positioned in the main body of the apparatus by said fixed projected portion, said driving bearing portion of said image bearing member and said driving bearing portion of said intermediate transfer member.    
     
     
         4 . An image forming unit according to  claim 1 , wherein driving forces are transmitted from the main body of the apparatus to said image bearing member and said intermediate transfer member independently of each other.  
     
     
         5 . An image forming unit according to  claim 1 , further comprising: 
 charging means for charging said image bearing member;    cleaning means for removing toner remaining on a surface of said image bearing member; and    toner carrying means for carrying the toner.    
     
     
         6 . An image forming unit according to  claim 1 , further comprising: 
 primary transfer means for applying a transfer bias to said intermediate transfer member; and    cleaning charging means for inducing charges opposite to those during transfer in toner remaining on a surface of said intermediate transfer member.    
     
     
         7 . An image forming unit according to  claim 1 , further comprising: 
 toner collecting means for collecting and accumulating therein toner remaining on a surface of said image bearing member or said intermediate transfer member.    
     
     
         8 . An image forming unit according to  claim 7 , wherein said image bearing member is disposed above said intermediate transfer member, and said toner collecting means is disposed below said intermediate transfer member.  
     
     
         9 . An image forming unit according to  claim 1 , wherein said image bearing member is a photosensitive drum, and said intermediate transfer member is an endless belt.  
     
     
         10 . An image forming apparatus comprising: 
 an image forming unit detachably mountable to a main body of said apparatus,    wherein said image forming unit comprises an image bearing member and an intermediate transfer member to which a toner image on said image bearing member is transferred, and said image bearing member and said intermediate transfer member are movable relative to each other in said image forming unit.    
     
     
         11 . An image forming unit detachably mountable to an image forming apparatus, said image forming unit comprising: 
 an image bearing member;    an intermediate transfer member to which a toner image on said image bearing member is transferred; and    transfer-contact-separation means for moving transfer means for transferring the toner image on said intermediate transfer member to a recording material into and out of contact with said intermediate transfer member.    
     
     
         12 . An image forming unit according to  claim 11 , wherein said intermediate transfer member is belt-shaped, said image forming unit has rollers around which said intermediate transfer member is stretched, and said transfer-contact-separation means has cams supported coaxially with said rollers, and can drive transmitting means for transmitting a driving force to said cams.  
     
     
         13 . An image forming unit according to  claim 11 , wherein when said image forming unit is mounted to a main body of the apparatus, said intermediate transfer member and said transfer means are maintained spaced apart from each other by said transfer-contact-separation means.  
     
     
         14 . An image forming unit according to  claim 11 , further comprising toner collecting means for collecting and accumulating therein toner remaining on a surface of said image bearing member or said intermediate transfer member.  
     
     
         15 . An image forming unit according to  claim 11 , further comprising driving-force transmitting means for transmitting a driving force from a main body of the apparatus to said transfer-contact-separation means, said driving-force transmitting means having lock means for enabling a transmission of the driving force only when said image forming unit is mounted to the main body of the apparatus.  
     
     
         16 . An image forming apparatus comprising: 
 an image forming unit detachably mountable to a main body of said apparatus,    wherein said image forming unit comprises an image bearing member, an intermediate transfer member to which a toner image on said image bearing member is transferred, and transfer-contact-separation means for moving transfer means for transferring the toner image on said intermediate transfer member to a recording material into and out of contact with said intermediate transfer member.    
     
     
         17 . An image forming apparatus according to  claim 16 , wherein said intermediate transfer member is belt-shaped, said image forming unit has rollers around which said intermediate transfer member is stretched, and said transfer-contact-separation means has cams supported coaxially with said rollers, and cam drive transmitting means for transmitting a driving force to said cams.  
     
     
         18 . An image forming apparatus according to  claim 17 , further comprising urging means for urging said transfer means against said rollers, and bearings for supporting said transfer means and abutting against said cams.  
     
     
         19 . An image forming unit detachably mountable to an image forming apparatus, said image forming unit comprising: 
 an image bearing member;    an intermediate transfer member to which a toner image on said image bearing member is transferred;    cleaning means for cleaning said intermediate transfer member; and    cleaning-contact-separation means for moving said cleaning means into and out of contact with said intermediate transfer member.    
     
     
         20 . An image forming unit according to  claim 19 , wherein said intermediate transfer member is belt-shaped, said image forming unit has rollers around which said intermediate transfer member is stretched, and said cleaning-contact-separation means has cams supported coaxially with said rollers, cam drive transmitting means for transmitting a driving force to said cams, urging means for urging said cleaning means against said rollers, and bearings for supporting said cleaning means and abutting against said cams.  
     
     
         21 . An image forming unit according to  claim 19 , wherein when said image forming unit is detached from a main body of the apparatus, said intermediate transfer member and said cleaning means are maintained spaced apart from each other by said cleaning-contact-separation means.  
     
     
         22 . An image forming unit according to  claim 19 , wherein said cleaning means induces charges opposite to those during transfer in toner remaining on a surface of said intermediate transfer member.  
     
     
         23 . An image forming unit according to  claim 19 , further comprising tone collecting means for collecting and accumulating therein toner remaining on a surface of said image bearing member or said intermediate transfer member.  
     
     
         24 . An image forming unit according to  claim 19 , further comprising driving-force transmitting means for transmitting a driving force from a main body of the apparatus to said cleaning-contact-separation means, said driving-force transmitting means having lock means for enabling a transmission of the driving force only when said image forming unit is mounted to the main body of the apparatus.  
     
     
         25 . An image forming apparatus comprising: 
 an image forming unit detachably mountable to a main body of the apparatus,    wherein said image forming unit comprises an image bearing member, an intermediate transfer member to which a toner image on said image bearing member is transferred, cleaning means for cleaning said intermediate transfer member, and cleaning-contact-separation means for moving said cleaning means into and out of contact with said intermediate transfer member.    
     
     
         26 . An image forming unit detachably mountable to an image forming apparatus, said image forming unit comprising; 
 an image bearing member;    an intermediate transfer member to which a toner image on said image bearing member is transferred;    toner collecting means for collecting therein toner removed from said image bearing member;    intermediate transfer member drive transmitting means for transmitting a driving force to said intermediate transfer member; and    toner carrying means for carrying the toner removed from said image bearing member to said toner collecting means,    wherein a driving-force transmission to said toner carrying means is effected through said intermediate transfer member drive transmitting means.    
     
     
         27 . An image forming unit according to  claim 26 , further comprising image bearing member drive transmitting means for transmitting a driving force to said image bearing member, wherein a driving-force path of said intermediate transfer member drive transmitting means and a driving-force path of said image bearing member drive transmitting means are paths discrete from each other.  
     
     
         28 . An image forming unit according to  claim 26 , further comprising toner agitating means for agitating the toner in said toner collecting means, wherein a driving-force transmission to said toner agitating means is effected through said intermediate transfer member drive transmitting means.  
     
     
         29 . An image forming unit according to  claim 26 , wherein the toner remaining on a surface of said intermediate transfer member is transferred to said image bearing member.  
     
     
         30 . An image forming apparatus comprising: 
 an image forming unit detachably mountable to a main body of the apparatus,    wherein said image forming unit comprises an image bearing member, an intermediate transfer member to which a toner image on said image bearing member is transferred, toner collecting means for collecting therein toner removed from said image bearing member, intermediate transfer member drive transmitting means for transmitting a driving force to said intermediate transfer member, and toner carrying means for carrying the toner removed from said image bearing member to said toner collecting means, and    wherein a driving-force transmission to said toner carrying means is effected through said intermediate transfer member drive transmitting means.    
     
     
         31 . An image forming apparatus according to  claim 30 , further comprising image bearing member drive transmitting means for transmitting a driving force to said image bearing member, wherein a driving-force path of said intermediate transfer member drive transmitting means and a driving-force path of said image bearing member drive transmitting means are paths discrete from each other.  
     
     
         32 . An image forming apparatus according to  claim 31 , further comprising a single drive source for imparting a driving force to said intermediate transfer member drive transmitting means and said image bearing member drive transmitting means.  
     
     
         33 . An image forming apparatus according to  claim 30 , further comprising transfer means for transferring the toner image on said intermediate transfer member to a recording material, wherein a driving-force transmission to said transfer means is effected through said intermediate transfer member drive transmitting means.  
     
     
         34 . An image forming unit detachably mountable to an image forming apparatus, said image forming unit comprising: 
 an image bearing member;    an endless belt to which a toner image on said image bearing member is transferred in a transferring portion;    a driving rotary member for driving said belt; and    a driven rotary member driven to be rotated by said belt,    wherein said belt is stretched around said driving rotary member and said driven rotary member, and    said transferring portion is located downstream of said driving rotary member and upstream of said driven rotary member in a moving direction of said belt.    
     
     
         35 . An image forming unit according to  claim 34 , wherein said image bearing member is a photosensitive drum, and a circumferential length of said photosensitive drum is substantially one integerth of the circumferential length of said belt.  
     
     
         36 . An image forming unit according to  claim 34 , wherein said image bearing member and said belt are driven by a single drive source, and a ratio between a gear for transmitting a driving-force from said single drive source to said image bearing member and a gear for transmitting a driving force from said single drive source to said driving rotary member is integer times.  
     
     
         37 . An image forming unit according to  claim 34 , wherein a diameter of said driving rotary member and a diameter of said driven rotary member are substantially equal to each other, and circumferential lengths of said driving rotary member and said driven rotary member are substantially one integerth of a circumferential length of said belt.  
     
     
         38 . An image forming unit according to  claim 37 , wherein the diameters of said driving rotary member and said driven rotary member are 25 mm to 35 mm.  
     
     
         39 . An image forming unit according to  claim 34 , further comprising primary transfer means opposed to said image bearing member with said belt interposed therebetween for transferring the toner image formed on said image bearing member to said belt.  
     
     
         40 . An image forming unit according to  claim 34 , comprising a first unit having said image bearing member, and a second unit having said belt, said first unit and said second unit being separable from each other.  
     
     
         41 . An image forming apparatus comprising: 
 an image forming unit detachably mountable to a main body of said apparatus,    wherein said image forming unit comprises an image bearing member, an endless belt to which a toner image on said image bearing member is transferred in a transferring portion, a driving rotary member for driving said belt, and a driven rotary member driven to be rotated by said belt,    said belt is stretched around said driving rotary member and said driven rotary member, and    said transferring portion is located downstream of said driving rotary member and upstream of said driven rotary member in a moving direction of said belt.    
     
     
         42 . An image forming apparatus according to claim  41 , further comprising transfer means for transferring the toner image on said belt onto a recording material in a transferring portion.  
     
     
         43 . An image forming apparatus according to claim  41 , wherein the transferring portion in which the toner image is transferred from said belt to the recording material is provided below the transferring portion in which the toner image is transferred from said image bearing member to said belt.