| 摘要 |
933,666. Printing surfaces; mounting means. JAMES NEILL & CO. (SHEFFIELD) Ltd. Sept. 29, 1961, No. 35010/61. Class 100 (2). [Also in Groups VIII and XXXV] A laminated magnetic holding device which may be adapted to cylindrical form for use with ferromagnetic backed printing sheets, comprises a plurality of plastic sheets loaded with powdered permanent magnet material of high coercive force, each sheet being magnetized perpendicular to its faces, together with a plurality of sheets of material of relatively high permeability and saturation density assembled in face-to-face contact with and in alternation with the magnetic sheets, alternate magnetic sheets being of reversed polarity so that the edges of the sheets of permeable material present pole faces of alternating polarity. In Fig. 1, plastic sheets 1 compounded of powdered barium ferrite and rubber, p.v.c. or like plastic are sandwiched between ferrous plates 2 the assembly being held together by rivets 4 and clamping plates 3A, 3B or by double-sided adhesive tape. The edges of the plastic sheet may level with the edges or the ferrous plates or slightly below. The gaps in the latter case may be fitted with material to provide a required surface. For use with printing sheets a magnetic cylinder is built up of alternate plastic and ferromagnetic annuli. |
