MAGNETO-OPTICAL PRINTING HEAD

摘要

Magneto-optical printing head for generating a grey-scale image on a recording substrate has a magneto-optical light-switching mask with light-switching elements which are switched thermomagnetically by the simultaneous positive or negative effect of heat pulses selectively generated from thin-film resistors applied to the light-switching elements. A magnetic field is applied to a coil between two possible states with in each case the direction of magnetization either parallel or antiparallel to the surface normals, whereby individual time control of the light-switching elements in n possible steps is effected by the single switching of all light-switching elements into the (first) starting state by the action of the positive magnetic field generated by the coil and subsequent switching into the second state by means of a second static magnetic field whose direction is opposite to that of the magnetic field of the coil, and by the action of heat pulses of n-1 point in time. The static magnetic field is generated by an arrangement of permanent magnets situated close to the light-switching elements.