Abstract: An ink dot printer includes an ink tank for storing magnetic ink, a pair of magnetic pole plates arranged opposite to each other to form a slit, one end of the pair of plates being immersed in the magnetic ink in the ink tank. An electromagnet magnetizes the paired magnetic pole plates to introduce the magnetic ink in the ink tank into the slit to form a magnetic ink film therein, and a plurality of needles arranged adjacent to one another in the longitudinal direction of the slit are each freely movable in the longitudinal direction of the needle between a first position where its one end portion is immersed in the magnetic ink film in the slit between the paired magnetic pole plates and a second position where its one end portion is projected from the magnetic ink film in the slit.

Abstract: An ink-dot printer comprises a magnetic ink storage tank storing magnetic ink, a pair of pole plates facing each other so as to define a slit one end portion of which is contacted with the magnetic ink supplied from the magnetic ink storage tank, an electromagnet for magnetizing the pole plates, thereby feeding the magnetic ink from the magnetic ink storage tank into the slit to form a magnetic ink curtain in the slit, and a plurality of needles arranged adjacent to one another along the longitudinal direction of the slit and adapted selectively to move in the longitudinal direction thereof between a first position where one end portion of each needle is immersed in the magnetic ink curtain in the slit and a second position where the one end portion is projected from the magnetic ink curtain in the slit, the cross-sectional area of the one end portion of each needle being made to narrower than that of the remaining portion of the needle so that the distance between the one end portions of any two adjacent nee

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 electroma

Abstract: An ink dot printer includes an ink tank having a magnetic ink supplying hole and an air opening; a pair of magnetic pole plates arranged to form a slit one end of which is immersed in magnetic ink in the ink tank; and an electromagnet for magnetizing the magnetic pole plates to introduce the magnetic ink in the ink tank into the slot to form a magnetic ink film. A plurality of needles arranged adjacent to one another along the longitudinal direction of the slit are each freely movable in its longitudinal direction between a first position where one end portion is immersed in the magnetic ink film in the slit, and a second position where the one end portion is projected from the magnetic ink film. Electromagnets selectively drive the needles to move them from the first position to the second position, wherein the needles selected force the magnetic ink adhered on their one ends at the first position, onto a recording paper to form dots of the magnetic ink.