Sheet flipping device

Abstract

A sheet flipping device comprising:a flipping element rotatably disposed adjacent to a sheet receiving plane and having, in its outer periphery, at least two insertion slots for insertion of a respective leading edge of a sheet to be flipped;a sheet transport device configured for feeding sheets with their respective leading edges into the insertion slots; anda controller configured to control the sheet transport device and a rotary drive (54) for the flipping element such that each sheet the leading edge of which has been inserted into one of the insertion slots is temporarily restrained while the transport mechanism continues to feed the sheet, so that the sheet flips over, and the sheet is then dropped onto the receiving plane,wherein each insertion slot has a mouth defined between a peripheral surface of the flipping element and a flexible finger that extends tangentially from said peripheral surface, the controller is configured to move one of the insertion slots into a sheet receiving position regardless of whether or not a trailing edge of a preceding sheet has left the sheet transport device, and the flexible finger has sufficient flexibility to be deflected by a sheet which has its trailing edge still held in the sheet transport device.

1 . A sheet flipping device comprising:
 a flipping element rotatably disposed adjacent to a sheet receiving plane and having, in its outer periphery, at least two insertion slots for insertion of a respective leading edge of a sheet to be flipped;   a sheet transport device configured for feeding sheets with their respective leading edges into the insertion slots; and   a controller configured to control the sheet transport device and a rotary drive for the flipping element such that each sheet the leading edge of which has been inserted into one of the insertion slots is temporarily restrained while the transport mechanism continues to feed the sheet, so that the sheet flips over, and the sheet is then dropped onto the receiving plane,   wherein each insertion slot has a mouth defined between a peripheral surface of the flipping element and a flexible finger that extends tangentially from said peripheral surface, the controller is configured to move one of the insertion slots into a sheet receiving position regardless of whether or not a trailing edge of a preceding sheet has left the sheet transport device, and the flexible finger has sufficient flexibility to be deflected by a sheet which has its trailing edge still held in the sheet transport device.   
     
     
         2 . The sheet flipping device according to  claim 1 , wherein the flipping element has two insertion slots with a mutual angular spacing of 180°. 
     
     
         3 . The sheet flipping device according to  claim 1 , wherein each insertion slot has an inner portion that is outwardly delimited by a rigid arm of the flipping element, and the flexible finger projects from a free end of said arm. 
     
     
         4 . The sheet flipping device according to  claim 3 , wherein the flexible finger is formed of a different material as the arm. 
     
     
         5 . The sheet flipping device according to  claim 4 , wherein the flexible finger is formed of a material with a greater elasticity than that of a material of which the arm is formed. 
     
     
         6 . The sheet flipping device according to  claim 1 , wherein the flipping element has, for each insertion slot, a pushing mechanism arranged to engage a sheet that has been dropped onto the receiving surface and then to push this sheet against a registration wall as the flipping element rotates. 
     
     
         7 . A method for stacking sheets, comprising the steps of:
 positioning a sheet adjacent a flipping element comprising in its outer periphery, at least two insertion slots, each insertion slot comprising a mouth defined between a peripheral surface of the flipping element and a flexible finger that extends tangentially from said peripheral surface;   rotating the flipping element, such that the flexible finger is moved radially inward by contact with the sheet, thereby at least partially narrowing the mouth;   the flexible finger flexing radially outward after passing the sheet, such that the mouth is further opened; and   the mouth receiving the sheet.   
     
     
         8 . The method according to  claim 7 , wherein the finger is sufficiently flexible such that contact with the sheet takes place without substantial displacement of and/or damage to the sheet. 
     
     
         9 . The method according to  claim 7 , wherein each insertion slot has an inner portion that is outwardly delimited by a rigid arm of the flipping element, and the flexible finger projects from a free end of said arm. 
     
     
         10 . The method according to  claim 9 , wherein the rigid arm is stationary with respect to the flipping element. 
     
     
         11 . The method according to  claim 9 , wherein the rigid arm is formed of a different, more rigid material than the flexible finger.