Patent GB-1013794-A (GB)
Title: Magnetic printing device
IPC: G03G19/00
Filed: 1962-10-10
Abstract: 1,013,794. Typewriters; selective printing. OLYMPIA WERKE A.G. Oct. 10, 1962 [May 23, 1962], No. 38340/62. Heading B6F. Machines with inkless printing.-A magnetic printing device comprises field-shaping type members 1, Fig. 1, consisting of independent magnetic paths 2, 3, separated by an air gap 5, which is filled with a non-magnetic or diamagnetic material 4 and the end faces 2a, 3a, of which are constructed in the form of characters to be printed, so that when the bipolar type members 1 are energized, magnetic lines of flux 11 emerge from the end face 2a, flow through a magnetizable recording medium 7 into the end face 3a to magnetize the recording medium longitudinally to produce latent magnetic character images thereon. Type-band actions.-The type members 1 may be aligned on an endless band 41, Fig. 9, separated therefrom by an intermediate non- magnetic member 40, with the polepieces 20a, 30a of the type members sliding past corresponding polepieces 50, 51, of electromagnets 42, 43, 44, allocated to particular printing positions, which as soon as the type members are in the required printing positions are magnetized in pulse-like manner to transfer a magnetic character image to the recording medium 7. Type-wheel actions.-In another embodiment, in Fig. 10, the type members 1 are arranged on a type drum 70, of a non-magnetic material and the magnetic polepieces 20a, 30a are adapted to lie on the inner diameter of the drum, when the energizing magnets 42, 43, 44 are accommodated in the interior of the drum. Type-lever actions.-In a further embodiment (not shown) the type members may have their magnetic paths formed of permanent magnets mounted on the ends of type bars, whereby the type members are struck against the magnetizable recording medium. In this case a common magnet, which is a permanent or an electromagnet, may be provided for the magnetization of the type and the electromagnet may be energized only during impact of the type. The type members also permit an impression with an ink-ribbon and paper. Types dies and printing surfaces.-The fieldshaping type members 1, Fig. 2a and 2b, consist of two independent magnetic paths 20, 30 separated by an air gap 5, which is filled with a non-magnetic material 4, such as hard solder, copper, or thermoplastic synthetic material and the magnetic paths may be fixed together by rivets or set-pins of non-magnetic material. Each magnetic path 20 and 30 is provided with end faces 2a, 3a, respectively, which are constructed in relief to form a character, e.g. " 0 " in Fig. 2a. In another embodiment in Fig. 7, one magnetic path 13 comprises a stencil-like excision in the form of the character, into which excision a second magnetic path 14, constructed in the form of a knife edge projects symmetrically about the air gap and the divided gap is filled with a non-magnetic material 4. In still another embodiment Fig. 7b comprises a first magnetic path including an iron ring 21, to which is spot-welded a flange 16a of a soft-iron cup 16, lined with a copper layer 17 and the bottom 16c of which is stamped through by an iron stamp 18 forming the second path and carrying at its end a raised type 23 of triangular cross-section. During the subsequent heating the non-magnetic material 19 becomes soft, forming on cooling a continuous rigid connection between the copper layer 17 and stamp 18. Finally the raised embossing 16c is removed by grinding to expose the type character. In a further embodiment (in Fig. 8c, not shown) an iron plate carrying a type face in relief is first coated with a layer of copper and then with a further external layer of iron and the type member is then ground down to expose the type face.