Sheet supplying device and image forming apparatus

Abstract

A sheet supplying device which supplies a sheet, including: a sheet supplying tray which stacks a bundle of sheets; a first air blowing section which blows air against a side of the bundle of sheets stacked on the sheet supplying tray; a second air blowing section which blows air from downstream of the bundle of sheets in a sheet conveyance direction, onto a leading section of the sheets; a vacuum conveyance section which vacuums an uppermost sheet of the bundle of sheets and conveys the sheets one by one; a shielding member which shields air blown from the first air blowing section; a vacuum detection sensor which detects that a sheet has been vacuumed by the vacuum conveyance section; and a control section which controls the shielding member to open so that air generated by the first air blowing section is blown to the bundle of sheets.

1 . A sheet supplying device which supplies a sheet, comprising:
 a sheet supplying tray which stacks a bundle of sheets;   a first air blowing section which blows air against a side of the bundle of sheets stacked on the sheet supplying tray;   a second air blowing section which blows air from a position downstream of the bundle of sheets in a sheet conveyance direction, onto a leading section of the sheets;   a vacuum conveyance section which vacuums an uppermost sheet of the bundle of sheets stacked on the sheet supplying tray and conveys the sheets one by one in the sheet conveyance direction;   a shielding member which shields against air blown by the first air blowing section;   a vacuum detection sensor which detects that a sheet has been vacuumed by the vacuum conveyance section; and   a control section which controls the shielding member to open or close so that air generated by the first air blowing section is blown to the bundle of sheets or not.   
     
     
         2 . The sheet supplying device of  claim 1 , wherein when the vacuum detection sensor detects that the sheet has been vacuumed by the vacuum conveyance section, the control section controls the shielding member so that air is not blown from the first air blow section. 
     
     
         3 . The sheet supplying device of  claim 1 , wherein the first air blow section comprises an air inlet and an air outlet, and the shielding member comprises a shutter which shields the air inlet or the air outlet. 
     
     
         4 . An image forming apparatus, comprising:
 an image forming section which forms an image on an image carrier;   a transfer section which transfers a toner image on the image carrier onto a sheet;   a sheet supplying device which conveys the sheet to the transfer section; and   a fixing device which heats and fixes the sheet carrying the toner image,   
       wherein the sheet supplying device comprises:
 a sheet supplying tray which stacks a bundle of sheets including plural sheets; 
 a first air blowing section which blows air against a side of the bundle of sheets stacked on the sheet supplying tray; 
 a second air blowing section which blows air, from a position downstream of the bundle of sheets in a sheet conveyance direction, onto leading sections of the sheet; 
 a vacuum conveyance section which vacuums an uppermost sheet of the bundle of sheets stacked on the sheet supplying tray and conveys the sheets one by one in the sheet conveyance direction; 
 a shielding member which shields air blown by the first air blowing section; 
 a vacuum detection sensor which detects that a sheet has been vacuumed by the vacuum conveyance section; and 
 a control section which controls the shielding member to open or close so that air generated by the first air blowing section is blown to the bundle of sheets or not. 
 
     
     
         5 . The image forming apparatus of  claim 4 , wherein when the vacuum detection sensor detects that the sheet has been vacuumed by the vacuum conveyance section, the control section controls the shielding member so that air is not blown from the first air blow section. 
     
     
         6 . The sheet supplying device of  claim 1 , wherein the first air blow section comprises an air inlet and an air outlet, and the shielding member comprises a shutter which shields the air inlet of the air outlet.