Sheet processing apparatus and image forming apparatus

Abstract

A sheet processing apparatus and an image forming apparatus can secure the stackability of a sheet when discharging a residual sheet. When a residual sheet is conveyed from a main body of an image forming apparatus to a first sheet stacking portion at turning on the power for the main body of the image forming apparatus, the trailing edge of the residual sheet is aligned first by a trailing edge aligning portion. And then, a residual sheet is moved to a sheet discharging position, in which the sheet is discharged onto a second sheet stacking portion, while the residual sheet, the trailing edge of which has been aligned, is being held by a holding member.

1 . A sheet processing apparatus comprising: 
 a first sheet stacking portion connected to a main body of an image forming apparatus for stacking thereon a sheet conveyed from the main body of the image forming apparatus;    a second sheet stacking portion provided downstream of said first sheet stacking portion with respect to a sheet conveying direction for stacking thereon the sheet discharged from said first sheet stacking portion after being treated on said first sheet stacking portion;    a trailing edge aligning portion for aligning a trailing edge in the sheet conveying direction of the sheet stacked on said first sheet stacking portion;    a discharging member having a holding member for holding the sheet, the trailing edge of which has been aligned by said trailing edge aligning portion, and while holding the sheet by said holding member, moving the sheet to a sheet discharging position, in which the sheet is discharged onto said second sheet stacking portion by releasing a holding by said holding member; and    a control device for controlling said discharging member in such a manner that, when a residual sheet remains in the main body of the image forming apparatus and the residual sheet is conveyed at turning on a power for the main body of the image forming apparatus, a trailing edge of the residual sheet is aligned by said trailing edge aligning portion, and then the residual sheet is moved to the sheet discharging position while the residual sheet is held by said holding member.    
   
   
       2 . A sheet processing apparatus according to  claim 1 , wherein said trailing edge aligning portion is provided with a regulating member, which is provided upstream of said first sheet stacking portion with respect to the sheet conveying direction for regulating the trailing edge of the sheet, and a sheet conveying member, which is rotatable forward and reversely, for abutting the sheet against said regulating member by conveying the sheet, which is conveyed onto said first sheet stacking portion, in a direction reverse to the sheet conveying direction after conveying the sheet in the sheet conveying direction.  
   
   
       3 . A sheet processing apparatus according to  claim 2 , further comprising a sheet detecting device for detecting the trailing edge of the sheet conveyed from the main body of the image forming apparatus, wherein when said control devices judges that the sheet conveyed by said sheet conveying member has passed said regulating member based on a signal from said sheet detecting device, said control device controls a drive of said sheet conveying member so as to abut the sheet against said regulating member by rotating said sheet conveying member reversely.  
   
   
       4 . An image forming apparatus comprising: 
 an image forming portion for forming an image on a sheet; and    a sheet processing apparatus as recited in  claim 1  for treating the sheet with the image formed by said image forming portion.    
   
   
       5 . An image forming apparatus according to  claim 4 , wherein said control device is provided in said sheet processing apparatus or a main body of said image forming apparatus.  
   
   
       6 . An image forming apparatus comprising: 
 an image forming portion for forming an image on a sheet; and    a sheet processing apparatus as recited in  claim 2  for treating the sheet with the image formed by said image forming portion.    
   
   
       7 . An image forming apparatus according to  claim 6 , wherein said control device is provided in said sheet processing apparatus or a main body of said image forming apparatus.  
   
   
       8 . An image forming apparatus comprising: 
 an image forming portion for forming an image on a sheet; and    a sheet processing apparatus as recited in  claim 3  for treating the sheet with the image formed by said image forming portion.    
   
   
       9 . An image forming apparatus according to  claim 8 , wherein said control device is provided in said sheet processing apparatus or a main body of said image forming apparatus.  
   
   
       10 . An image forming apparatus comprising: 
 an image forming portion for forming an image on a sheet;    a first sheet stacking portion for stacking thereon the sheet with the image formed by said image forming portion;    a second sheet stacking portion provided downstream of said first sheet stacking portion with respect to a sheet conveying direction for stacking thereon the sheet discharged after being treated on said first sheet stacking portion;    a trailing edge aligning portion for aligning a trailing edge in the sheet conveying direction of the sheet stacked on said first sheet stacking portion;    a discharging member having a holding member for holding the sheet, the trailing edge of which has been aligned by said trailing edge aligning portion, and while holding the sheet by said holding member, moving the sheet to a sheet discharging position, in which the sheet is discharged onto said second sheet stacking portion by releasing a holding by said holding member; and    a control device for controlling said discharging member in such a manner that, when a residual sheet remains upstream of said first sheet stacking portion with respect to the sheet conveying direction and the residual sheet is conveyed at turning on a power for the image forming apparatus, a trailing edge of the residual sheet is aligned by said trailing edge aligning portion, and then the residual sheet is moved to the sheet discharging position while the residual sheet is held by said holding member.