Hitachi, Ltd.

Hitachi-lg Data Storage, Inc.

Eijiro Tazawa

Osamu Kawamae

Kuniaki Hirayama

Masanori Kochi

Yoshio Uemura

Toshihiko Imachi

Akihiro Nakajima

Kiyokazu Watanabe

A watermark information detection process prevents prolonging of time required for setup process when no watermark information can be detected from an optical disc where watermark information has been recorded. During a setup, the number of retrials is limited. Weighting of the retrial is changed so that detection of watermark information is performed when it is confirmed that watermark information is recorded. This enables detection of information for copyright protection in an appropriate processing time.

Data production method and apparatus

A rotary magnetic recording and reproducing apparatus includes a stationary cylinder formed on a lower portion of an outer peripheral surface thereof with a guide lead for guiding a lower edge of a magnetic tape and defining a tape running face on an upper portion of the outer peripheral surface thereof, a first bulge portion formed on an upper edge portion of the tape running face of the stationary cylinder on a tape leaving side of the upper edge portion of the tape running face and a second bulge portion which is smaller in height than the first bulge portion and formed on the upper edge portion of the tape running face on the tape leaving side thereof and in the vicinity of the first bulge portion on a tape incoming side of the first bulge portion. The first bulge portion serves to relax shock or vibration of a magnetic tape leaving the magnetic head and the second bulge portion serves to improve 'head-touch' of the magnetic tape.

Rotary magnetic head cylinder device for reduced vibration and proper

Growing community of inventors

Tokyo, Japan

Eijiro Tazawa