Image forming apparatus

Abstract

An image forming apparatus ( 100 ) includes a rotation driving portion ( 40 ) configured to drive rotation of a discharge roller ( 31 ), a shift driving portion ( 50 ) configured to drive shift of the discharge roller ( 31 ), thereby causing shift, and a control portion ( 200 ) configured to control driving of rotation of the rotation driving portion ( 40 ) and driving of shift of the shift driving portion ( 50 ). The control portion ( 200 ) controls a discharge timing for sheet (P) that is being discharged such that a trailing edge (P 2 ) of the sheet (P) moves past the discharge roller ( 31 ) during the shift of the discharge roller ( 31 ).

1 . An image forming apparatus that sorts sheets discharged by a discharge roller for discharging sheets to the outside, by causing shift of the discharge roller along an axial direction of the discharge roller, comprising:
 a rotation driving portion configured to drive rotation of the discharge roller;   a shift driving portion configured to drive shift of the discharge roller, thereby causing the shift; and   a control portion configured to control driving of rotation of the rotation driving portion and driving of shift of the shift driving portion;   wherein the control portion controls a discharge timing for a sheet that is being discharged such that a discharge direction upstream edge of the sheet moves past the discharge roller during the shift of the discharge roller.   
     
     
         2 . The image forming apparatus according to  claim 1 , wherein the discharge timing at which the discharge direction upstream edge of the sheet that is being discharged moves past the discharge roller during the shift is a timing at which a movement velocity of the shift of the discharge roller is a maximum velocity. 
     
     
         3 . The image forming apparatus according to  claim 1 , wherein the discharge timing at which the discharge direction upstream edge of the sheet that is being discharged moves past the discharge roller during the shift is substantially equivalent to a timing at which the discharge roller reaches a movement end in the axial direction. 
     
     
         4 . The image forming apparatus according to  claim 1 , wherein the control portion reduces a revolving velocity of the discharge roller before the discharge direction upstream edge of the sheet that is being discharged moves past the discharge roller. 
     
     
         5 . The image forming apparatus according to  claim 4 , wherein the control portion reduces the revolving velocity of the discharge roller when starting the shift of the discharge roller. 
     
     
         6 . The image forming apparatus according to  claim 4 , wherein the control portion rotates the discharge roller at a first revolving velocity, at a second revolving velocity that is higher than the first revolving velocity after a discharge direction downstream edge of the sheet has moved past the discharge roller, at a third revolving velocity that is higher than the first revolving velocity and lower than the second revolving velocity before the discharge direction upstream edge of the sheet moves past the discharge roller, and again at the first revolving velocity after the discharge direction upstream edge of the sheet has moved past the discharge roller. 
     
     
         7 . The image forming apparatus according to  claim 1 , wherein the control portion starts the shift of the discharge roller after the discharge direction upstream edge of the sheet that is being discharged has moved past a closest roller disposed closest to the discharge roller on an upstream side therefrom in a discharge direction of the sheet. 
     
     
         8 . The image forming apparatus according to  claim 1 , wherein a timing of starting the shift of the discharge roller can be adjusted. 
     
     
         9 . The image forming apparatus according to  claim 2 , wherein the control portion starts the shift of the discharge roller after the discharge direction upstream edge of the sheet that is being discharged has moved past a closest roller disposed closest to the discharge roller on an upstream side therefrom in a discharge direction of the sheet. 
     
     
         10 . The image forming apparatus according to  claim 3 , wherein the control portion starts the shift of the discharge roller after the discharge direction upstream edge of the sheet that is being discharged has moved past a closest roller disposed closest to the discharge roller on an upstream side therefrom in a discharge direction of the sheet. 
     
     
         11 . The image forming apparatus according to  claim 4 , wherein the control portion starts the shift of the discharge roller after the discharge direction upstream edge of the sheet that is being discharged has moved past a closest roller disposed closest to the discharge roller on an upstream side therefrom in a discharge direction of the sheet. 
     
     
         12 . The image forming apparatus according to  claim 5 , wherein the control portion starts the shift of the discharge roller after the discharge direction upstream edge of the sheet that is being discharged has moved past a closest roller disposed closest to the discharge roller on an upstream side therefrom in a discharge direction of the sheet. 
     
     
         13 . The image forming apparatus according to  claim 6 , wherein the control portion starts the shift of the discharge roller after the discharge direction upstream edge of the sheet that is being discharged has moved past a closest roller disposed closest to the discharge roller on an upstream side therefrom in a discharge direction of the sheet. 
     
     
         14 . The image forming apparatus according to  claim 2 , wherein a timing of starting the shift of the discharge roller can be adjusted. 
     
     
         15 . The image forming apparatus according to  claim 3 , wherein a timing of starting the shift of the discharge roller can be adjusted. 
     
     
         16 . The image forming apparatus according to  claim 4 , wherein a timing of starting the shift of the discharge roller can be adjusted. 
     
     
         17 . The image forming apparatus according to  claim 5 , wherein a timing of starting the shift of the discharge roller can be adjusted. 
     
     
         18 . The image forming apparatus according to  claim 6 , wherein a timing of starting the shift of the discharge roller can be adjusted.