Magnetic tape device and method of controlling magnetic tape device

• US 5,923,494 A
• Filed: 03/20/1996
• Issued: 07/13/1999
• Est. Priority Date: 03/20/1995
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Toki, Kenji, Okuyama, Kouetsu, Sakai, Kazuo, Nemoto, Yasuhiro, Arisaka, Toshihiro
• Primary Examiner(s): Tran, Thang V.
• Assistant Examiner(s): WONG, KIN C
• Application Number:
  US08/618,600
• Time in Patent Office: 1,210 Days
• Field of Search: 360/71, 360/78.02, 360/77.12, 360/74.3, 360/75
• US Class Current: 360/78.02
• CPC Class Codes: G11B 15/1808 Driving of both record carrier and head G11B15/467 takes precedence; mounting of head G11B5/52
• CPC Class Codes: G11B 15/602 for track selection, acquisition or following
• CPC Class Codes: G11B 5/00817 on longitudinal tracks only, e.g. for serpentine format recording
• CPC Class Codes: G11B 5/54 with provision for moving the head into or out of its operative position or across tracks
• CPC Class Codes: G11B 5/5504 across tape tracks
• CPC Class Codes: G11B 5/5508 Control circuits therefor G11B5/5513 takes precedence
• CPC Class Codes: G11B 5/584 for track following on tapes

Abstract

There is provided a magnetic tape device capable of highly accurate positioning at a high speed. For this purpose, the head is driven in the direction of the width of the tape by eliminating the friction between the tape the head. In order to allow positioning in the direction of the width of the tape, even if a servo signal cannot be read from a servo track, the absolute position of the head from a reference position is detected, and the head is controlled based on the absolute position.

Claims

1. A magnetic tape device wherein a servo signal read from a servo track provided on a magnetic tape and a magnetic head having one or more head cores is moved in the direction of the width of the tape to position said head cores on predetermined data tracks, comprising:

a positioning control portion for controlling the positioning of said magnetic head, said positioning control portion being responsive to a moving speed of the tape and controlling said magnetic head So that said magnetic head moves between different data tracks in the direction of the width of the tape when the tape is moving at a speed equal to or higher than a predetermined value greater than zero and said magnetic head does not move between the different data tracks when the tape is moving at a speed below the predetermined value including when the tape is stationary.

2. The magnetic tape device according to claim 1, further comprising:

a guide provided on the magnetic head, which guide is put in contact the magnetic tape in the direction of the width thereof for regulating the movement of the magnetic tape in the direction of the width thereof.

3. A magnetic tape device according to claim 1, wherein said positioning control portion is responsive to the moving speed of the tape for controlling said magnetic head so that said magnetic head moves between different data tracks in the direction of the width of the tape only when the tape is moving at the speed which is equal to or higher than the predetermined value greater than zero and for controlling said magnetic head so not to move said magnetic head when the tape is not moving at a speed equal to or higher than the predetermined value greater than zero.

4. A magnetic tape device wherein a magnetic head is positioned in the direction of the width of a magnetic tape, comprising:

a contact-vibration means which contacts an end of the magnetic tape in the direction of the width thereof or a surface of the magnetic tape and which vibrates the magnetic tape in the direction of the width thereof or in an out-of-plane direction;

a driving means for moving said contact-vibration means so that the contact-vibration means is put into contact with and moved away from the magnetic tape; and

a control portion for controlling said driving means in response to a speed of movement of the magnetic tape so that said driving means moves the contact-vibration means to a position where the contact-vibration means contacts the magnetic tape when the moving speed of the magnetic tape is higher than zero and equal to or lower than a predetermined value.

5. A magnetic tape device according to claim 4, wherein said control portion controls said driving means so that said driving means moves the contact-vibration means to a position where the contact-vibration means contacts the magnetic tape only when the moving speed of the magnetic tape is higher than zero and equal to or lower than the predetermined value and controls said driving means so that the contact-vibration means is out of contact with the magnetic tape when the magnetic tape is not moving at a speed which is higher than zero and equal to or lower than the predetermined value.

6. A method of controlling a magnetic tape device which includes a moving means for moving a magnetic head having one or more head cores in the direction of the width of a magnetic tape and wherein a servo signal is read from a servo track provided on the magnetic tape to position the magnetic head in the direction of the width of the magnetic tape, the method comprising the steps of:

coarsely positioning the magnetic head in the vicinity of a target track in the direction of the width of the magnetic tape and in response to a speed of movement of the magnetic tape which is equal to or higher than a predetermined value greater than zero during the repositioning of the magnetic head to the magnetic tape and not positioning the magnetic head when the magnetic tape moves at a speed lower than the predetermined value including when the magnetic tape is stationary; and

starting the following of the target track immediately before a recording or reading operation is started on the target track specified on the magnetic tape.

7. A method according to claim 6, wherein the step of coarsely positioning the magnetic head in response to a speed of movement of the magnetic tape which is equal to or higher than the predetermined value greater than zero includes moving the magnetic head in response to the speed of movement of the magnetic tape only when the magnetic tape is moving at a speed equal to or higher than the predetermined value greater than zero and not moving the magnetic head when the magnetic tape is not moving at a speed which is equal to or is not higher than the predetermined value greater than zero.

8. A method of controlling a magnetic tape device, comprising the steps of:

positioning a magnetic head in the direction of the width of a magnetic tape according to a servo signal obtained from a servo track on the magnetic tape and in response to a speed of movement of the magnetic tape which is equal to or higher than a predetermined value greater than zero and not positioning the magnetic head when the magnetic tape moves at a speed lower than the predetermined value including when the magnetic tape is stationary;

reciprocating the magnetic head in the vicinity of a target track after the magnetic head is coarsely positioned in the vicinity of a target track during a track switching operation; and

following the track thereafter.

9. A method according to claim 8, wherein the step of positioning the magnetic head includes moving the magnetic head in response to the speed of movement of the magnetic tape only when the speed of movement of the magnetic tape is equal to or higher than a predetermined value greater than zero and not moving the magnetic head when the magnetic tape is not moving at a speed which is equal to or is not higher than the predetermined value greater than zero.

10. A method of controlling a magnetic tape device, comprising the steps of:

positioning a magnetic head in the direction of the width of a magnetic tape according to a servo signal obtained from a servo track on the magnetic tape and in response to a speed of movement of the magnetic tape which is equal to or higher than a predetermined value greater than zero and not positioning the magnetic head when the magnetic tape moves at a speed lower than the predetermined value including when the magnetic tape is stationary; and

performing one or more reciprocating operations with said head in the direction of the width of the magnetic tape while the magnetic head is moved to a target track from a track to which the magnetic head has been positioned during a track switching operation.

11. A method according to claim 10, wherein the step of positioning the magnetic head includes moving the magnetic head in response to the speed of movement of the magnetic tape only when the speed of movement of the magnetic tape is equal to or higher than the predetermined value greater than zero and not moving the magnetic head when the magnetic tape is not moved at a speed which is equal to or higher than the predetermined value greater than zero.