JPS6423420A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To exactly detect a defective part by recording production information directly to the arbitrary point of a ferromagnetic metallic layer formed by means such as vapor deposition on the surface of a tape-shaped substrate, reading and analyzing this production information in later stages and setting production conditions in the later stages. CONSTITUTION:Operation data format such as film specifications, numbers, sizes, target film thickness of vapor deposition, vapor deposition number and data of vapor deposition inputted to a computer 31 are called onto a CRT 32. The data are recorded via a typed signal input device 33 onto the film G for vapor deposition. The feed length of the film is determined by a film length meter 36 from the number of the pulses emitted by a pulse counter 35 directly coupled to a coating roller 7 and is fed to the computer 31. While the thickness of the film under vapor deposition is kept monitored by a film thickness measuring instrument 34, the signal of the defective vapor deposition is emitted when the average value of the thickness of the vapor deposited film in the thickness direction exceeds the value of + or -1-10% of the target film thickness of the vapor deposition. The signal of un-vapor deposition is emitted when the un-vapor deposited part is generated by the abnormal discharge of an electron gun D. These signals are magnetically recorded on the film G from a magnetic input head 23a.