Metal particulate media with a thin magnetic layer were developed for high density magnetic recording. A thin magnetic layer can be stably provided by simultaneous double-layer coating method with a non-magnetic underlayer. The underlayer was found to improve not only electromagnetic properties but also runnability and durability of magnetic media. These technologies have been applied in Hi-8 and W-VHS tapes.
Thin magnetic tape has been developed relating to problem of strength. This paper reports the thin tape technology of the reinforce. The results are summarized as follows; Required strength of thinner tape is different between tape directions, and (1) toward the longitudinal direction, required strength is high young modulus, and (2) toward the transvers direction, required strength is high yield strength. According to these results, we develop TC-40 tape, that shows good performance as TC-30 tape.
We are developing a photochromic optical recording medium with an extra-high recoding density. We have focused on development of high durability compounds, a new non-destractive readout method and a new crosstalk reduction technology for multi-frequency optical recording.
The overwrite characteristics in perpendicular magnetic recording is discussed based on the transition shift. The transition shift during the write process caused by the interference field in the vicinity of the recording position was measured and quantified. The dependences of the overwrite on the recording density were explained. It was simultaneously confirmed that the bi-layered head can improve the overwrite by suppressing the transition shift.