paint so as to satisfy the above relationships of the particle sizes examples of the binder resins contained in the magnetic layer and the backcoating layer are vinyl chloride resins e g vinyl chloride vinyl acetate copolymers vinyl chloride vinyl acetate vinyl alcohol copolymers vinyl chloride acrylate copolymers vinyl chloride vinylidene chloride copolymers vinyl chloride acryronitrile copolymers and vinyl chloride vinyl acetate maleic acid copolymers thermoplastic polyurethane resins thermosetting polyurethane resins polyester resins phenoxy resins polyvinyl buryral resins cellulose derivatives epoxy resins and mixtures thereof to these resins hydrophilic groups such as carboxylic acid groups sulfonic acid groups sulfonatc groups phosphoric acid groups phosphate groups amine groups or ammonium salt groups may be introduced to improve the dispersibility of the powder particles in the resins or acrylic double bonds may be introduced to the resins so that the resins can be cured by irradiation examples of the solvent to prepare the paints for the layers are alcohols e g ethanol propanol butanol etc esters e g methyl acetate ethyl acetate butyl acetate etc ketches e g methyl ethyl ketone methyl isobutyl ketone cyclohexanone etc ethers e g tetrahydrofuran dioxane etc aromatic hydrocarbons e g benzene toluene xylene etc aliphatic hydrocarbons e g heptane hexane cyclohexane etc chlorinated hydrocarbons e g methylene chloride ethylene chloride chloroform etc and the like among them a mixed solvent of cyclohexanone and toluene is preferred to the above layers a lubricant such as saturated or unsaturated higher fatty acids higher fatty acid amides fatty acid esters higher alcohols silicone oils mineral oils edible oils fluorinated oils etc may be added as an additional additive the above components in predetermined amounts are dispersed with a ball mill or a sand mill to prepare the magnetic or backcoating paint and coated on the.