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The magnetization process in contact printing is considered to be the same process as an ideal anhysteretic magnetization process. In the anhysteretic magnetization process a self-demagnetization effect by an internal field is an important factor, especially at short wavelength. Therefore, the internal field effect should be evaluated dynamically depending on the instantaneous strength of the diminishing bias field. It was shown that such an anhysteretic magnetization process including the internal field effect can be represented as a first-order feedback system in an automatic control theory. Thus the numerical analyzing method for the anhysteretic magnetization was established, and excellent coincidence between the numerically computed result and the experimental result in the contact printing was obtained. Consequently the distribution patterns of the magnetization and the internal field in the duplicated tape was computed.

A new type of ferrite called hot pressed ferrite (HPF) which is processed at a very high temperature and pressure during sintering, and which has almost the same density and lack of porosity as single crystal ferrite is described. Furthermore, HPF has many advantages over single-crystal ferrites, including the fact that it is isotropic. The permeability, expansion coefficients, and wearing characteristics of an HPF ingot are identical in all directions, which facilitates head design and manufacture. The magnetic, physical, and ether properties of HPF are described in detail and these properties are compared with those of conventional, high-density, and single-crystal ferrites. The way HPF can be used to design heads giving improved signal-to-noise ratio, higher resolution, and exceptionally long life is also described. The experimental results relate mainly to heads for audio, video, and instrumentation recording.

The anhysteretic contact printing process was simulated by a computer with the Preisach diagram which was modified by the Onsager field effect. The printed magnetization was determined by successive magnetizations at each peak of the decreasing transfer field. The second quadrant demagnetization was also discussed afterward, but the effect of the reproducing head was not included. The actual magnetization will be situated between the magnetization before and after the second quadrant demagnetization. As a result of the simulation, considerable saturation was found at the surface layer of the printed tape when the input signal intensity of the recorded master tape becomes large. The transfer efficiency decreases rapidly, corresponding to the increase of the signal field intensity. These results show qualitatively good agreement with experimental results published heretofore.

A magnetoresistive (MR) head produces high output. A stripe type MR head, however, has poor wave-length response due to its stripe width loss and has limitation in reducing track width due to its configuration. A new MR head, therefore, is proposed here to obtain extremely narrow track width. This head can achieve very high areal density and has no wear problems, since having flux guide cores.

According to the increasing demands for magnetic tape printing especially for video tape, the magnetic tape duplication using a contact process is one of the most attractive solutions. There are two major methods, i. e. anhysteretic transfer and thermal transfer. The coercivity of the master tape should be 2.5 times higher than the slave by computer simulation for anhysteretic transfer, but is not important for thermal transfer. The highest coercivity of the slave tape will be decided by the master tape which, in turn, is limited by the recording head saturation for anhysteretic transfer, however, the thermal characteristics of coercivity and magnetic induction under Tc are more dominant for thermal transfer. The tape surface roughness as well as the coercivity is very important for short wavelength printing. In this paper, the properties of the master and slave tapes for anhysteretic and thermal transfer are discussed with theoretical and experimental results.