Abstract: A method of field annealing a thin-film electromagnetic read/write head formed of magnetic-field-responsive material having a known Curie temperature. Such a head also includes an electric coil for operatively exciting the head. The method includes the steps of heating the head to a temperature less than the Curie temperature, and then cooling the head while applying electric current to the coil sufficient to induce magnetic flux in the head. The foregoing steps, properly applied, align the magnetic-field-responsive structure, such as magnetic domains in a soft magnetic material, in the direction of operative flux flow in the head.

Abstract: A method is presented for producing a controlled-distribution, toned magnetic image unit on a planar-like magnetic-image-storage medium having a magnetizable facial expanse using magnetically attractable toner particles having differing sizes. The method includes the steps of creating in such a facial expanse a latent magnetic image formed of magnetic vectors which extend generally parallel with the facial expanse adjacent the perimeter of the image and which extend with increasing angularity with respect to the facial expanse plane with distance inwardly from the perimeter; positioning the image sufficiently close to a mass of such particles to draw the particles magnetically to the latent image; and by said positioning and drawing, selectively capturing particles on the facial expanse extending over the latent image with the sizes of the captured particles generally tending to increase in size with distance inwardly from the perimeter of the image.

Abstract: An apparatus for transferring toner from an incompressible, flexible magnetic image-storage medium to paper. The apparatus includes a cylindrical drum having a layer of resilient backing material on an inner support structure. An image-storage medium is slidably disposed on the backing material. A pressure roller also having a resilient surface layer is placable against the roller to form, in combination therewith, a pinch roller through which paper is transported during toner transfer. Deformation of the respective resilient layers in the roller and drum during transfer produces a complimentary slip action between the resilient backing and image-storage medium. This allows the paper and medium to move together without smearing the associated toner images.

Abstract: A magnetic-image read/write head including inner and outer, substantially co-planar, symmetrically arranged pole portions. In one embodiment, the head is disclosed with the inner pole portion presenting a substantially full-circular facial expanse, and with the outer pole portion presenting an annular facial expanse surrounding that of the inner pole portion. In another embodiment, each of the two pole portions presents a substantially annular facial expanse with the inner pole being hollow. In both embodiments, the inner pole portion has a magnetic permeability which is significantly lower than that of the outer pole portion. An image unit written on a magnetic-image-storage medium by the head takes the form, generally, of a dot characterized by an appreciably larger magnetic field intensity adjacent its perimeter than inside the perimeter.

Abstract: Apparatus for producing a preselected final image in a travelling magnetic image-storage medium, which image is formed of an arrangement of individual magnetic image units and line segments formed of a plurality of linearly disposed contiguous units having a predetermined center-to-center spacing. Adjacent units in adjacent line segments have substantially the same predetermined center-to-center spacing when viewed in a direction substantially normal to the direction of travel, and also have a known maximum actual center-to-center spacing. Plural magnetic writing heads, each capable of producing an image unit, are distributed to have, when viewed in a direction substantially parallel with the direction of travel of the medium, a center-to-center spacing equalling that of contiguous units in a line segment. The actual center-to-center spacing between heads capable of forming adjacent image units in a line segment exceeds the mentioned center-to-center spacings between adjacent units.

Abstract: Apparatus for producing in a magnetic image-storage medium a high-resolution, smooth-edge-defining magnetic image. Such is accomplished through the cooperative action of two, opposite-polarity, concentric magnetic poles which function to create, on a face in such a medium, a somewhat doughnut-shaped defined magnetized zone, which zone is characterized by multi-directionally oriented magnetic vectors distributed generally with spherical geometry. The magnetic poles are created by exciting electrically magnetic-flux-inducing spiral coils which are spaced from the magnetic poles.

Abstract: Apparatus for transferring toner magnetically adhering to magnetic images stored in a magnet image-storage medium to a toner-adherable receiving medium such as paper. Included is a platen which presses the paper against the storage medium to form regions of contact and noncontact between the paper and storage medium. A boundary between the two regions is defined by a line of contact. The apparatus also includes magnets for producing a magnetic field in the paper and storage medium which is asymetrical with respect to the line of contact. The field is stronger in the region of noncontact than in the region of contact. In the preferred embodiment, the field originates from a pair of spaced-apart, confronting magnetic poles disposed on a side of the paper opposite from the storage medium. The apparatus is structured to produce selectively a field in the storage medium having a magnetizing force less than or, alternatively, greater than, the coercivity of the storage medium.