PURPOSE: To facilitate the printing of patterns such as characters in desired sizes on a sheet paper in any size by moving a recording means on a recording paper according to printing signals as provided on the bottom of a box which capable of straight movement and rotary motion.

CONSTITUTION: An input section KB comprising a key switch and an indicator DSP are provided on the top surface of a sheet printer and a recording pen PEN and adjustable balls B freely movable in any direction with respect to right and left drive wheels RW and LW separately driven by drivers (e.g. stepping motors) LM and RM are provided on the bottom thereof. This enables straight movement and rotary motion of the box on a sheet paper. According to signals from the key input section KB, a controller CPU controls the driving of the drivers LM and RM and the vertical movement of the recording pen PEN with an aid of a character generator CG and registers R1 and R2 whereby characters in any size are drawn on the sheet paper.