PURPOSE: To exactly send paper into a vertical stacker, by providing claws on paper discharge rollers so that the paper discharged into the stacker by the rotation of the rollers is further pushed into the stacker by the claws.

CONSTITUTION: When paper discharge rollers 15, 16 with claws 27 are rotating, the rear edge of paper 22 is surely engaged with the claws so that the paper is sent out while being certainly pushed up in the direction of paper discharge. When the rear edge of the paper 22 has reached such a rotation angle position as to disengage from the claws 27 by the weight of the paper 22, as a result of the further rotation of the rollers 15, 16, the paper drops along a paper housing surface in a stacker 12. Subsequently, the rotation of the claw 27 in the same direction as that of the paper discharge roller 16 acts so that the paper 22 is pushed into the stacker 12 while the paper is driven down to the bottom 12a of the stacker. Sheets of paper are thus sequentially trued up and housed in the stacker 12.