Compagnie Internationale Pour L'informatique Cii-honeywell Bull (societe

Compagnie Internationale Pour L'informatique

Andre Lucan

Jean-Philippe Voirin

Henri Morizot

Francois Pon

A powder suitable for developing latent magnetic images comprising magnetic particles coated with a mixture of a thermoplastic resin and a silane. A method for producing the said powder comprising hot-forming a mixture of magnetic particles, a thermoplastic resin and a silane, cooling and reducing the cooled mass to a fine powder.

Powder for developing latent images and a method of producing the powder

A magnetic recording element made in accordance with the present invention comprises a layer of magnetic material applied to a carrier formed from a material of high magnetic permeability. A layer of non-ferrous, non-magnetic material is interposed between the carrier and the layer of magnetic material. The layer of non-magnetic material has a thickness between 20 and 40 microns. The magnetic recording element enables sharply defined magnetized domains to be obtained and is in a simple and repeatable fashion, by using a process in which the materials applied to the carrier of the element undergo no chemical transformation. To this end, the non-magnetic layer is produced by successively depositing, on the carrier which is used as a cathode, a first layer of copper obtained from an alkaline electrolytic solution, and then a second layer of copper which is obtained from an acid electrolytic solution.

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Belfort, France

Andre Lucan