Patent ID: 7441767

Claim:
A sheet feeder detachably attached in an inserting manner to a recording apparatus, comprising: a stacking member for stacking sheets of a recording medium, the stacking member being movable up and down; a rotating drive gear receiving a driving force from said recording apparatus, said drive gear transmitting said driving force to move said stacking member up and down; a lifting member for moving said stacking member up and down; a first curved rack portion on a first sidewall of the sheet feeder, said first rack portion having a curvature matching a circumference of said drive gear; and a first planet gear moving along the circumference of said drive gear in accordance with rotation of and in mesh with said drive gear, said first planet gear being sandwiched between said drive gear and said first rack portion and being engaged with said drive gear and said first rack portion, wherein said lifting member moves up and down in accordance with movement of said planet gear.