Image forming apparatus

Abstract

In an image forming apparatus in which a plurality of feeders can be added, a main body driving portion is provided in an apparatus main body and a drive feeder having a driving portion is provided among the plurality of feeders. The main body side driving portion drives an adjacent feeder, and the driving portion of the drive feeder drives the drive feeder and a feeder adjacent to the drive feeder. In the image forming apparatus, it is unnecessary to provide a dedicated driving portion in an additional feeder, it is also unnecessary to supply a driving force to the additional feeder from the apparatus main body. Therefore, no limitation is required of the additional feeder, and cost increase for an entire product can be prevented.

What is claimed is:  
     
         1 . An image forming apparatus wherein a plurality of feeders each including a sheet containing portion and a sheet feeding portion for feeding a sheet can be added in series in an apparatus main body, comprising: 
 a main body side driving portion provided in said apparatus main body; and    a drive feeder added in a predetermined position among said plurality of added feeders,    wherein a feeder adjacent to said apparatus main body among said plurality of added feeders is driven by said main body side driving portion, and    wherein said drive feeder and a feeder adjacent to said drive feeder are driven by said driving portion.    
     
     
         2 . An image forming apparatus according to  claim 1 , wherein, in case that another feeder is connected between said feeder adjacent to said apparatus main body and said drive feeder, said another feeder is driven by said main body side driving portion.  
     
     
         3 . An image forming apparatus according to  claim 1 , wherein, in case that another feeder is further connected to said feeder adjacent to said drive feeder, said another feeder is driven by said driving portion provided in said drive feeder.  
     
     
         4 . An image forming apparatus according to  claim 1 , wherein said feeders and said drive feeder comprise a sheet containing portion for containing sheets and a sheet feeding portion for feeding a sheet from said sheet containing portion, and drive said sheet feeding portion by a driving force from said main body side driving portion or said driving portion to feed a sheet.  
     
     
         5 . An image forming apparatus according to any one of  claims 1  to  4 , wherein said feeders other than said drive feeder provided with said driving portion are constituted in common.  
     
     
         6 . An image forming apparatus according to  claim 4 , wherein said drive feeder comprises a drive transmitting portion for driving said sheet feeding portion by a driving force of said driving portion provided in said drive feeder and transmitting a driving force to said feeder adjacent to said drive feeder, and 
 wherein said adjacent feeder comprises a relay portion to which a driving force of said driving portion is transmitted via said drive transmitting portion and transmits the driving force received by said relay portion to said sheet feeding portion.    
     
     
         7 . An image forming apparatus according to  claim 6 , wherein a feeder having a same structure as a structure of said feeder driven by said main body side driving portion of said apparatus main body is connected to said feeder, and a driving force from said main body side driving portion is sequentially transmitted to said feeders via said relay portion and said drive transmitting portion.  
     
     
         8 . An image forming apparatus according to  claim 4 , wherein said feeder which is adjacent to said apparatus main body and is driven by said main body side driving portion comprises a relay portion to which a driving force from said main body side driving portion is transmitted and a drive transmitting portion for transmitting the driving force received by said relay portion to said sheet feeding portion, and said drive transmitting portion has the same structure as a structure of a drive transmitting portion of said drive feeder and a drive transmitting portion of said feeder driven by said driving portion of said drive feeder.  
     
     
         9 . An image forming apparatus according to  claim 6 , wherein said driving portion of said drive feeder is made interchangeable with said relay portion of a feeder which is adjacent to said drive feeder and is driven by said driving portion.  
     
     
         10 . An image forming apparatus according to  claim 1 , wherein said feeders are stacked vertically below said apparatus main body, and said drive feeder is arranged below said feeder driven by said main body side driving portion.  
     
     
         11 . An image forming apparatus including: 
 an apparatus main body provided with an image forming portion;    a plurality of feeders which are stacked below said apparatus main body;    a sheet feeding cassette for containing sheets and a pick-up roller for delivering a sheet from said sheet feeding cassette which are provided in said respective feeders;    a main body side motor provided in said apparatus main body;    a gear train for transmitting a driving force of said main body side motor to said pick-up roller of said feeder provided adjacently below said apparatus main body;    a drive feeder provided among said stacked plurality of feeders and has a feeder side motor; and    a gear train for transmitting a driving force of said feeder side motor to said pick-up roller of a feeder provided adjacently below said drive feeder.    
     
     
         12 . An image forming apparatus according to  claim 11 , wherein said feeder adjacent to said apparatus main body and said feeder adjacent to said drive feeder have a common structure.  
     
     
         13 . An image forming apparatus according to  claim 11 , wherein each of said feeders has a feed roller and a retard roller for separating sheets delivered by said pick-up roller individually, a convey roller for conveying the sheet separated individually, and a clutch for transmitting or not transmitting a driving force to each roller, and said clutch is controlled by a control portion provided in said apparatus main body.  
     
     
         14 . An image forming apparatus according to  claim 13 , wherein said gear trains comprise transmission gears for receiving a driving force from said apparatus main body or from said plurality of feeders and input gears meshing with said transmission gears, and a driving force is transmitted to said pick-up roller and said feed roller from said input gears via said clutch.  
     
     
         15 . An image forming apparatus according to  claim 14 , wherein said feeder side motor of said drive feeder and said transmission gears of said plurality of feeders are made interchangeable.