Processing device and image forming device

Abstract

After post-processes have been performed on sheet bundles which have been stacked in a post-processing tray 16 , the sheet bundles are alternately shifted in the paper conveyance lateral direction and each of these shifted sheet bundles are conveyed from the post-processing tray 16 to the discharge port by a sheet receiving member 18 , and the sheet bundle is discharged in the shifted condition to a paper discharge tray 13 by a pair of discharge rollers 12 which are located at the discharge port. The pair of discharge rollers 12 have an upper discharge roller 22 and an opposing lower discharge roller 24 which open and close freely, and a solenoid for switching between a closed condition which grasps the sheet bundle and an opened condition which does not grasp the sheet bundle. The lower discharge roller 22 and the upper discharge roller 24 are closed by the solenoid 40 at predetermined timing based on the sheet size.

1 . A post-processing device, comprising: 
 a post-processing tray for stacking sheets;    post-processing means for performing post-processing on sheet bundles comprising a plurality of sheets which have been stacked in the post-processing tray;    sheet conveying means for alternately shifting each sheet bundle post-processed by the post-processing means in a direction orthogonal to a conveyance direction, and conveying each of the shifted sheet bundles to a discharge port;    a pair of discharge rollers for discharging sheet bundles which have been conveyed by the sheet conveying means from the discharge port, having an upper discharge roller and an opposing lower discharge roller which freely open and close in order to achieve a closed state where the sheet bundle can be grasped and discharged and an open state where the rollers are mutually separated;    a sheet discharging tray for receiving sheet bundles discharged by means of the pair of discharge rollers;    driving means for switching the upper discharge roller and the opposing lower discharge roller between the closed state and the open state; and    controlling means for controlling the timing for switching the lower discharge roller and the upper discharge roller between the open state and the closed state in response to the paper size or the number of sheets.    
   
   
       2 . The post-processing device according to  claim 1 , wherein the controlling means switches from the open state to the closed state after a fixed period of time from the moment the lead edge of the sheet bundle in the conveyance direction reaches the pair of discharge rollers.  
   
   
       3 . The post-processing device according to  claim 1 , wherein the controlling means switches from the open state to the closed state after a fixed period of time from the moment sheet bundle conveyance by the sheet conveying means begins.  
   
   
       4 . The post-processing device according to  claim 1 , wherein the controlling means controls the timing for switching between the open state and the closed state in order to nip the trailing end side of the sheet bundle in the conveyance direction as the size of the sheet bundle increases.  
   
   
       5 . The post-processing device according to  claim 1 , wherein the controlling means controls the timing for switching between the open state and the closed state in order to nip the trailing end side of the sheet bundle in the conveyance direction as the number of pages in the sheet bundle increases.  
   
   
       6 . An image forming device, comprising: 
 an image forming unit for forming an image on a sheet;    a post-processing device for performing post-processing on a sheet onto which an image is formed by the image forming unit;    the post-processing device comprising:    a post-processing tray for stacking sheets;    post-processing means for performing post-processing on sheet bundles comprising a plurality of sheets which have been stacked in the post-processing tray;    sheet conveying means for alternately shifting each sheet bundle post-processed by the post-processing means in a direction orthogonal to a conveyance direction, and conveying each of the shifted sheet bundles to a discharge port;    a pair of discharge rollers for discharging sheet bundles which have been conveyed by the sheet conveying means from the discharge port, having an upper discharge roller and an opposing lower discharge roller which freely open and close in order to achieve a closed state where the sheet bundle grasped and discharged and an open state where the rollers are mutually separated;    the sheet discharging tray for receiving sheet bundles discharged by means of the pair of discharge rollers;    driving means for switching the upper discharge roller and the opposing lower discharge roller between the closed state and the opened state; and    controlling means for controlling the timing for switching the lower discharge roller and the upper discharge roller between the opened state and a closed state in response to the paper size or the number of sheets.    
   
   
       7 . The image forming device according to  claim 6 , wherein the controlling means switches from the open state to the closed state after a fixed period of time from the moment the lead edge of the sheet bundle in the conveyance direction reaches the pair of discharge rollers.  
   
   
       8 . The image forming device according to  claim 6 , wherein the controlling means switches from the opened state to the closed state after a fixed period of time from the moment sheet bundle conveyance by the sheet conveying means begins.  
   
   
       9 . The image forming device according to  claim 6 , wherein the controlling means controls the timing for switching between the opened state and the closed state in order to nip the trailing end side of the sheet bundle in the conveyance direction in response to the size of the sheet bundle.  
   
   
       10 . The image forming device according to  claim 6 , wherein the controlling means controls the timing for switching between the opened state and the closed condition in order to nip the trailing end side of the sheet bundle in the conveyance direction as the number of pages in the sheet bundle increases.