| 摘要 |
An improved sheet feeder mechanism includes a D-shaped roller that is mounted on a shaft and is positioned transversely to a direction of sheet feed. A D-roller gear is mounted on the shaft and has both a non-recessed geared region and a recessed non-geared region that extends partially about a circumference of the D-roller gear. A shaft extension extends from and is attached to the shaft, and a spring engages the shaft extension to cause the shaft and the D-roller gear to rotate to a position that enables a gear drive to engage the non-recessed geared region of the D-roller gear. A spiral cam assembly is mounted for rotation with the gear drive and includes a spiral cam that is positioned between and resiliently bears upon inner and outer annuli of the cam assembly. A control arm engages both the spiral cam and the shaft extension and is responsive to rotation in a first direction of the cam assembly to enable the spring to move the shaft extension and D-roller gear to a position where a non-recessed, geared region aligns with the gear drive. The control arm is further responsive to rotation in a second direction of the cam assembly, after the first direction rotation, to enable rotation of the D-roller gear by the gear drive so as to cause a sheet feed.
|
