Ink dot printer

Abstract

An ink dot printer comprises: an ink tank storing magnetic ink; a pair of magnetic pole plates arranged opposite to each other to form a slit whose one end is immersed in the magnetic ink in the ink tank; an electromagnet magnetizing the paired magnetic pole plates to introduce the magnetic ink in the ink tank into the slit to form a magnetic ink film therein; a plurality of needles arranged adjacent to one another along the longitudinal direction of the slit where each is freely movable in its longitudinal direction between a first position where its one end portion is immersed in the magnetic ink film in the slit and a second position where its one end portion is projected from the magnetic ink film in the slit; electromagnets for selectively driving the needles to move from the first position to the second position; and stoppers which collide with the needles in the course of their moving from the first position to stop the needles at the second position; wherein the driving force produced in the electromagnets is so set that the magnetic ink is flied from the end faces of the one end portions of the needles onto a recording paper thanks to an inertia of the magnetic ink on the end faces of the one end portions of the needles which is caused by the collision of the needles with the stoppers.