Taizou Hamada

Printed Media technology for an effective and inexpensive servo track writing of HDDs

As an alternative method for the servo track writing of hard disk drives (HDDs), a magnetic contact duplication method by using a lithographically patterned master disk has been proposed and investigated. On the master disk, magnetic film pattern according to the information signal to be printed on slave disks is provided by a lithography technique. In this method, unlike the anhysteretic process of the conventional contact duplication method for magnetic tapes, the master information never disappears when a large external field is applied to the master while printing. This duplication method, as we call the Printed Media technology, can provide a very effective and inexpensive lump-sum servo track writing method for HDDs.

A novel magnetic printing technique for perpendicular recording media

A novel magnetic printing technique designed for perpendicular hard-disk media using a lithographically formed master disk was satisfactorily demonstrated. In this paper, optimum conditions for the magnetic printing process are discussed by analyzing the waveforms of signals experimentally retrieved from the printed media and by numerical simulation using a finite element method.

Magnetic printing technology - application to HDD

As the recording density of hard disk drives is being rapidly increased, the current servo track writing method using a conventional servo track writer has become more costly and technically difficult. In order to solve the problem, the authors propose a new magnetic contact duplication technology using a lithographically patterned master disk and discuss the printing process reliability for practical implementation to the product drives, in particular, from the viewpoint of master-slave contact issues. The air channel structure provided on the master disk surface allows close surface contact between the master and the slave disks, yielding very small amplitude modulation of the printed signal. The master disk was found durable over 1 million printing shots without giving any serious damage to the lithographically patterned ferromagnetic film. Moreover, organic and inorganic contamination tests show that the contact printing operation does not increase contamination on the printed disks. The magnetic printing technique can also be successfully applied to perpendicular recording media using the same master disk as for longitudinal media.

A novel magnetic printing technique for perpendicular media

Summary form only given. A magnetic printing technique for longitudinal media using a lithographically formed master disk has been proposed and satisfactorily demonstrated (W. Bernard and W. Buslik, 1975; T. Ishida et al., 2001; A. Saito et al., 2001). However, promising printing techniques for perpendicular media have not yet been proposed. We report a satisfactory implementation of a novel magnetic printing technique designed for perpendicular media.