PURPOSE: To simplify a sleeve replacement by rotatably supporting a hollow unit slightly rotatable and/or axially movable shaft, and incorporating only a hole for receiving an end of a shaft in a first sidewall.

CONSTITUTION: A first sidewall 1 has a wide cutout 3. Support plates 10, 11 have a width completely covering the cutout 3, and have a plurality of holes 13, 14, 15, 16 of a range of a separate seam 12 extended vertically. A first shaft 27 is guided via the holes 13, 19, 23 coincident with first row, and projected over an outer surface of a second sidewall 2. A hollow cylinder 30 is supported to two bearings 28, 29 to the shaft 27. The cylinder 30 supports a replaceable sleeve 31 for holding an image on an outer periphery. And, the shaft 27 is supported to an eccentric sleeve 34 useful to adjust a registration in the sidewall 2. And, an opposite holder 35 is operated from an upper side at a protruding end of the shaft 27.