Paper feeder and image forming apparatus

Abstract

When a recording medium is not detected even after an elapse of a predetermined period of time since a paper feeding unit fed the recording medium, the paper feeding unit is operated, to execute an assisting operation for assisting conveying of the recording medium.

1 . An paper feeder comprising:
 a feeding unit configured to execute an operation for feeding a recording medium and then, stop the operation;   a conveyance unit configured to convey the fed recording medium fed by the paper feeding unit; and   a detection unit configured to detect the conveyed recording medium conveyed by the conveyance unit, wherein   when the detection unit does not detect the conveyed recording medium at a predetermined timing, the feeding unit executes an assisting operation for assisting conveying of the recording medium.   
     
     
         2 . The paper feeder according to  claim 1 , wherein when the detection unit does not detect the recording medium even if the assisting operation is executed, it is determined that defective conveyance of the recording medium has occurred and a conveying operation is stopped. 
     
     
         3 . The paper feeder according to  claim 1 , wherein when the assisting operation is executed while the feeding unit feeds a plurality of recording media, it is determined whether the execution of the assisting operation is permitted depending on whether a trailing edge of the recording medium has passed through the feeding unit. 
     
     
         4 . The paper feeder according to  claim 1 , wherein a number of times the assisting operation is executed is set based on a length in a conveyance direction of the recording medium and a distance in a conveyance path from a leading edge of the recording medium that has not been fed, to the detection unit. 
     
     
         5 . The paper feeder according to  claim 1 , wherein a number of times the assisting operation is executed is set based on a type of the recording medium. 
     
     
         6 . The paper feeder according to  claim 1 , wherein a number of times the assisting operation is executed is set based on a degree of wear of the feeding unit. 
     
     
         7 . An paper feeder apparatus comprising:
 a feeding unit configured to execute an operation for feeding a recording medium and then, stop the operation;   a conveyance unit configured to convey the fed recording medium fed by the paper feeding unit;   a detection unit configured to detect the conveyed recording medium conveyed by the conveyance unit; and   an image forming unit configured to form an image on the detected recording medium,   wherein when the detection unit does not detect the conveyed recording medium at a predetermined timing, the feeding unit executes an assisting operation for assisting conveying of the recording medium.   
     
     
         8 . The paper feeder apparatus according to  claim 7 , wherein when the detection unit does not detect the recording medium even if the assisting operation is executed, it is determined that defective conveyance of the recording medium has occurred and a conveying operation is stopped. 
     
     
         9 . The paper feeder apparatus according to  claim 7 , wherein when the assisting operation is executed while the feeding unit feeds a plurality of recording media, it is determined whether the execution of the assisting operation is permitted depending on whether a trailing edge of the recording medium has passed through the feeding unit. 
     
     
         10 . The paper feeder apparatus according to  claim 7 , wherein a number of times the assisting operation is executed is set based on a length in a conveyance direction of the recording medium and a distance in a conveyance path from a leading edge of the recording medium that has not been fed, to the detection unit. 
     
     
         11 . The paper feeder apparatus according to  claim 7 , wherein a number of times the assisting operation is executed is set based on a type of the recording medium. 
     
     
         12 . The paper feeder apparatus according to  claim 7 , wherein a number of times the assisting operation is executed is set based on a degree of wear of the feeding unit.