Patent ID: 6948710

Claim:
A method for feeding a sheet material for a sheet feeding apparatus, comprising the steps of: providing a feeding means for forwarding a sheet material to a separation unit, said feeding means being in contact with a sheet material loaded on a sheet loading member; providing a taper member provided thereon with a tapered face, said taper member being brought into pressed contact with said feeding means at a nip forming portion, and said tapered face colliding with a leading edge of said sheet material; providing further on said taper member with a contact face of a protruded portion, said contact face being aligned parallel to a tangent of sheet feeding direction to be brought into contact with said feeding means; forwarding said sheet material to said separation unit; and separating said sheet material by means of said tapered face of taper member under following conditions adapted to said sheet material feeding; P>R f ·A /(μ 1 −μ P12 ) P<R f ·A/Δμ P A =sin θ P2 +μ 2 ·cos θ P2 , where P: feeding pressure, R f : a vertical drag caused by sheet material bending exerted onto leading edge of said sheet material through said taper face of taper member, μ 1 : coefficient of friction between said feeding means and said sheet material, μ 2 : coefficient of friction between said tapered face of taper member and said leading edge of said sheet material, μ P12 : coefficient of friction between first and second sheet materials, Δμ P : a difference in coefficients of friction between said sheet materials, and θ P2 : an angle between a tangent to said nip forming portion and said sheet forwarding direction.