Sheet separating mechanism of an auto sheet feeder and auto sheet feeder incorporating the same

Abstract

An auto sheet feeder used for a device comprises an upper frame, a pick roller and a sheet separating mechanism secured on the upper frame. The sheet separating mechanism includes a bracket and a pair of arms disposed on the bracket and spring-biased toward the pick roller. A separator pad is disposed on the bracket and spring-biased toward the pick roller. A press plate is positioned on the bracket and presses against the separator pad. A torsion spring mounted above the press plate has at least two coil portions. Two adjacent ends of the coil portions extend toward the same side and then joint each other to form a contact portion which always props the upper frame. Two ends of the torsion spring have a retaining arm respectively. The two retaining arms are opposite each other and pivotally engage to two sides of the press plate respectively. The torsion spring is compressed by the press plate when the sheets push the separator pad and pushes the press plate and the separator pad to be reposition after the lowermost one of the sheets is separated.

1 . A sheet separating mechanism for an auto sheet feeder having a pick roller and an upper frame, the mechanism comprising:
 a bracket;   a pair of spring arms disposed on the bracket and spring-biased toward the pick roller for maintaining a plurality of sheets on the pick roller during transportation of the sheets;   a separator pad disposed on the bracket and spring-biased toward the pick roller for cooperating with the pick roller to permit further transportation of a lowermost sheet of the plurality of the sheets;   a press plate positioned on the bracket and pressing against the separator pad; and   a torsion spring mounted above the press plate and having at least two coil portions spaced and opposite to the adjacent coil portion, two adjacent ends of the coil portions extending toward the same side and then jointing each other to form a contact portion which always props the upper frame, two ends of the torsion spring having a retaining arm respectively, the two retaining arms pivotally engaging to two sides of the press plate respectively;   wherein the torsion spring is compressed by the press plate when the sheets push the separator pad to detach from the pick roller and pushes the press plate and the separator pad to be reposition after the lowermost one of the sheets is separated.   
   
   
       2 . The sheet separating mechanism of an auto sheet feeder as claimed in  claim 1 , wherein the bracket further comprises a support board, the bottom of the support board bending and extending backward to form a prop board, two fixing pegs extending downward from the bottom of the prop board, two fixing holes being defined in the separator pad, the two fixing pegs being inserted into the two fixing holes respectively so as to secure the separator pad on the bracket. 
   
   
       3 . The sheet separating mechanism of an auto sheet feeder as claimed in  claim 1 , wherein the spring arms are part of a pick spring mounted to the bracket, the pick spring further including a spring press portion, a separator press portion being formed on the surface of the separator pad, the spring press portion of the pick spring pressing on the separator press portion. 
   
   
       4 . The sheet separating mechanism of an auto sheet feeder as claimed in  claim 2 , further comprising a press pad, the press pad including a pad holder and a pad press portion, the backside of the prop board of the bracket being dent to form a fixing groove, the pad holder of the press pad being fixed in the fixing groove, the pad press portion being pressed upon the sheets to prevent curling of the sheets. 
   
   
       5 . An auto sheet feeder for a device where separation of a single sheet from a plurality of sheets is desired, the feeder comprising:
 an upper frame;   a pick roller; and   a sheet separating mechanism secured on the upper frame, wherein the sheet separating mechanism comprising
 a bracket; 
 a pair of spring arms disposed on the bracket and spring-biased toward the pick roller for maintaining the plurality of sheets on the pick roller during transportation of the sheets; 
 a separator pad disposed on the bracket and spring-biased toward the pick roller for cooperating with the pick roller to permit further transportation of a lowermost sheet of the plurality of the sheets; 
 a press plate positioned on the bracket and pressing against the separator pad; and 
 a torsion spring mounted above the press plate and having at least two coil portions spaced and opposite to the adjacent coil portion, two adjacent ends of the coil portions extending toward the same side and then jointing each other to form a contact portion which always props the upper frame, two ends of the torsion spring having a retaining arm respectively, the two retaining arms pivotally engaging to two sides of the press plate respectively; 
 wherein the torsion spring is compressed by the press plate when the sheets push the separator pad to detach from the pick roller and pushes the press plate and the separator pad to be reposition after the lowermost one of the sheets is separated.