PURPOSE: To reduce the cost, supress generation of eddy current, lower temperature rise coefficient and thereby obtain a magnetic core just suitable for high speed printing by winding band shaped steel plate which has been punched for fitting excitation coil like a roll and thereby forming the stacked structure of magnet core.

CONSTITUTION: A magnet core for printing 10 having the stacking structure is obtained by winding the band shaped steel plate which has been punched and it is engaged between the fixing ring 12 at the center and fitting flange 11 at the circumference. A core C having the almost trapezoidal section of excitation coil and a cylindrical core D located at the circumference thereof are thus formed, a coil lead inserting hole 13 is bored on the core D corresponding to the slit formed between the cores C and D and simultaneously a protrusion 14 is provided at the rear side of core 10. Thus, welding is carried out here. The band shaped steel plate is respectively provided with cutaway part Sa for forming the core C, cutaway part Sb for forming the recess part between the core C and core D, punch hole Sc for forming a hole 13 and cutaway part Sd for forming protrusion 14.