JPH0576687B

• Main Authors: KYOHARA TADASHI, SUZUKI MASAYASU, ISHIGAKI KAZUO, SUZUKI TAKESHI, SUZUKI JIRO
• Format: Patent
• Language: English
• Published: 25.10.1993
• Edition: 5
• Subjects: ADHESIVES; BOOK COVERS; BOOKBINDING; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; COLOUR PRINTING; CORRECTING FLUIDS; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDEDFOR; DYES; FILES; FILLING PASTES; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; INKS; LINING MACHINES; LOOSE LEAVES; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; MOVABLE-STRIP WRITING OR READING APPARATUS; NATURAL RESINS; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; PERFORMING OPERATIONS; PHYSICS; POLISHES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITYFEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOTOTHERWISE PROVIDED FOR; PRINTING; PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; SPECIAL PRINTED MATTER; STAMPS; TRANSPORTING; TYPEWRITERS; USE OF MATERIALS THEREFOR; WOODSTAINS

PURPOSE:To prevent forgery by successively laminating a magnetic layer of high coercive force, high magnetic permeability layer and magnetic layer of low coercive force on one surface of a base and providing a leuco dye heat sensitive color forming layer consisting of a sulfonate-contg. polyester resin as a binder, barrier layer and protective layer essentially consisting of a polyurethane resin on the other surface. CONSTITUTION:Normal data is recorded to the high coercive force of a magnetic recording medium constituted by successively laminating the high coercive force magnetic layer, the high magnetic permeability layer 13 and the low coercive force magnetic layer 14 on one surface of the base 11 consisting of a nonmagnetic sheet and a dummy signal is recorded to the low coercive force layer. The heat sensitive recording layer to be formed on another surface of the base is the leuco dye heat sensitive color forming layer consisting of the sulfonate-contg. polyester resin as the binder and further the protective layer essentially consisting of the polyurethane resin is provided via the barrier layer thereon. The magnetic permeability layer 3 is magnetically saturated when a card for reproduction is brought into tight contact with the magnetic surface and a magnetic field for transfer is applied thereto. The magnetic permeability is then decreased and the magnetic shielding effect is lost. The normal data recorded to the high coercive force layer 12 and the dummy signal recorded to the low coercive force layer 4 are thereby mixedly reproduced on the card for reproduction. The forgery is thus prevented.