# US 6,724,549 B2 · Magnetic medium transfer quality control device

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- Number: US 6,724,549 B2
- Document ID: US6724549B2
- Status: Granted
- Kind: B2
- Application number: 09/897,579
- Filed: 2001-07-03
- Published: 2002-02-14
- Granted: 2004-04-20
- Earliest claimed: 2000-07-03
- Assignees: Fuji Electric Co., Ltd.
- Inventors: Hironori Mine
- Web page: https://patentgrep.com/patent/US6724549B2

## CPC

- G11B 27/36: Monitoring, i.e. supervising the progress of recording or reproducing {(for digital recording G11B20/00 and s.gr.; for monitoring, testing or measuring of TV recorders of the type covered by H04N5/76 and subgroups, see H04N17/06)}
- G11B 5/865: {by contact "printing"}
- G11B 33/10: Indicating arrangements; Warning arrangements {(G11B15/04, G11B19/04, G11B27/34, G11B27/36 take precedence)}
- G11B 2220/20: Disc-shaped record carriers
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)

## Abstract

In the case where a magnetic transfer process is used to record a specific magnetic pattern during the magnetic disk manufacturing process, a read/write tester for conducting a glide height test and a read/write test and a particle testing means are provided at the front section of a magnetic transfer device. The tester records a specific magnetic pattern onto a magnetic disk in a magnetic transfer method. An optical testing device, a read/write tester for conducting a glide height test, and a read/write test in sampling are provided at the rear section of the device. This enables the detection of consecutive disk abnormalities caused by particles, which are adhered a master disk or put between the magnetic disk and the master disk. A transfer quality control device collects the results of the respective tests, so that the quality can be controlled using the results. Accordingly, the present invention assures the desired quality of a magnetic disk produced after transfer.

## Claims

### Claim 1

A magnetic medium transfer quality control device for use in a magnetic disk manufacture line, in which a magnetic transfer process is performed by bringing a master disk, on which magnetic properties have previously been formed in a predetermined pattern, into contact with a magnetic disk to write a magnetic servo pattern, said magnetic medium transfer quality control device comprising:
data collection means for collecting data from the results of at least one of the following tests: a glide height test, a read/write test and a test for particles conducted before said magnetic transfer process; a visual test, a sampling glide height test and a sampling read/write test after said magnetic transfer process; and
determination means for making a predetermined determination according to the collected data concerning test results to determine whether or not there is an abnormal condition in said magnetic transfer process.

### Claim 2 (depends on 1)

A magnetic medium transfer quality control device according to claim 1, wherein said determination means determines a plurality of consecutive disks as being defective in said visual test, said sampling glide height test or said sampling read/write test, after said magnetic transfer process.

### Claim 3 (depends on 1)

A magnetic medium transfer quality control device according to claim 1, wherein said determination means compares the respective results of said sampling glide height test and said sampling read/write test after said magnetic transfer process with the results of said visual test after said magnetic transfer process, thereby enabling output of data for use in optimizing a set value for determining whether magnetic disks are defective or not.

### Claim 4 (depends on 1)

A magnetic medium transfer quality control device according to claim 1, wherein said determination means is capable of determining that a result of said test for particles before said magnetic transfer process is worse than a predetermined value.