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1. 发明专利

JP2003228927A MAGNETIC DISK DEVICE MAGNETIC RECORDING MEDIUM, AND SERVO WRITE SYSTEM 审中-公开
公开(公告)号：JP2003228927A
公开(公告)日：2003-08-15
申请号：JP2002022679
申请日：2002-01-31
申请人： HITACHI LTD
发明人： TOMIYAMA HIROSHI , HAMAGUCHI KATSUHIKO , KIKUKAWA ATSUSHI
IPC分类号： G11B5/65 , G11B5/596 , G11B5/667 , G11B20/12 , G11B21/10
摘要： PROBLEM TO BE SOLVED: To provide a servo write system which seldom has a servo error for a magnetic disk drive which uses a vertical medium. SOLUTION: The magnetic disk drive is mounted with a medium having a servo area so constituted that at least one point where no servo sector is present on a ray connecting the center of rotation of a recording medium and one arbitrary point on the outermost circumferential track of the recording medium is present on the outermost circumferential track in a system characterized by B×N>2π, where B is the angle of an area that a servo pattern track occupies to the center of rotation and N is the number of servo samples. COPYRIGHT: (C)2003,JPO

2. 发明专利

JPH0927101A MAGNETIC MEMORY METHOD AND MAGNETIC MEMORY DEVICE 失效
公开(公告)号：JPH0927101A
公开(公告)日：1997-01-28
申请号：JP17235995
申请日：1995-07-07
申请人： HITACHI LTD
发明人： TOMIYAMA HIROSHI , SUZUKI MIKIO , TAKANO KOJI , SHIROISHI YOSHIHIRO , TSUCHIYA REIJIROU , MATSUOKA SHINYA
IPC分类号： G11B5/09 , G11B5/02
摘要： PROBLEM TO BE SOLVED: To attain high-density and high-frequency recording without changing a recording head material and specifically reducing the distance between a magnetic head and a magnetic recording medium and without deteriorating the overwriting characteristic of the magnetic recording medium, the magnetic head and a recording and reproducing amplifier. SOLUTION: The design of a magnetic memory device is executed in such a manner that the various parameters determined by the magnetic head, the magnetic recording medium, recording amplifier, etc., satisfy the following equation 1, equation 2 or equation 3: v×(tr +tf )/2

3. 发明专利

JP2000011336A MAGNETIC HEAD AND MAGNETIC DISK DEVICE 失效
公开(公告)号：JP2000011336A
公开(公告)日：2000-01-14
申请号：JP16982298
申请日：1998-06-17
申请人： HITACHI LTD
发明人： SHIMOKOSHI MASAYOSHI , DOI TAKESHI , TOMIYAMA HIROSHI , KODAMA NAOKI , IDE HIROSHI
IPC分类号： G11B5/39 , G11B5/265
摘要： PROBLEM TO BE SOLVED: To provide a magnetic head and a magnetic disk device capable of obtaining an enough reproduced output and also obtaining an enough offtrack margin in the magnetic disk device which uses a recording and reproduction separation type head and especially whose track density exceeds 10 kTPI. SOLUTION: In this magnetic disk device provided with the recording and reproduction separation type head using an induction type head for the recording of a medium and using a magnetorestive head for the reproduction of the medium, the relation among the reproducing track width R of the magnetorestive head, the signal recording width W of the induction type head and the signal erasing width E of the induction type head is E>=R>=W. Moreover, the track density of the medium is equal to or larger than 10 kTPI. Furthermore, the device has the width of a magnetic sensing part corresponding to the reproducing track width R and widths of magnetic poles corresponding to the signal recording width W including an erasing part corresponding to the signal erasing width E and has the relation of E>=R>=W.

4. 发明专利

JPH11250401A MAGNETIC DISK DEVICE 失效
公开(公告)号：JPH11250401A
公开(公告)日：1999-09-17
申请号：JP5178798
申请日：1998-03-04
申请人： HITACHI LTD
发明人： TOMIYAMA HIROSHI , SHISHIDA KAZUHISA , HAMAGUCHI KATSUHIKO , TAKANO KOJI
IPC分类号： G11B5/012 , G11B5/187 , G11B5/23
摘要： PROBLEM TO BE SOLVED: To optimize track widths of the magnetic heads and to improve the yield of magnetic heads by using heads whose track widths are different in accordance with the assembled positions of the magnetic heads. SOLUTION: Positioning accuracies of magnetic heads 0, 5 respectively being at the nearest head position HD#0 and the farthrest head position HD#5 from the bearing part 10 of a spindle motor 9 are respectively considered as V0, V5. The amplitude displacement which is to be generated in the spindle 9 due to the variation in respective balls of the bearing part 10 of a head position farther from the bearing part 10 is geater and as a result, respective positioning accuracies of the magnetic heads 0, 5 become to be V5>V0. Then, interference of recorded information between adjacent tracks are made uniform by setting magnetic pole widths of the magnetic 0, 5 so as to become a relation of Tww5= Tww0-(V5-V0) by changing magnetic pole widths Tww0, Tww5 of the magnetic heads 0, 5 while considering positioning accuracies. Less sensitive hands can be used where positioning accuracies are satisfactory.

5. 发明专利

JPH11203807A INFORMATION STORAGE DEVICE 失效
公开(公告)号：JPH11203807A
公开(公告)日：1999-07-30
申请号：JP449698
申请日：1998-01-13
申请人： HITACHI LTD
发明人： IDE HIROSHI , TOMIYAMA HIROSHI , NISHIDA YASUTAKA , HAMAGUCHI KATSUHIKO , TAKANO KOJI , MARUYAMA YOJI , NAKAMURA ATSUSHI , SAWAGUCHI HIDEKI
IPC分类号： G11B5/012 , G11B5/596 , G11B7/08 , G11B19/04 , G11B21/10
摘要： PROBLEM TO BE SOLVED: To lower an upper limit of a threshold value so that a recording magnetization pattern of a track is not overlapped on a recording magnetization pattern of an adjacent track by providing exclusive areas for recording a pattern for detecting dislocation on plural positions on the same track with a data recording area. SOLUTION: A dislocation detecting address pattern 301 is arranged at the head of a dislocation detecting pattern area 204. When data are recorded, recording operation is interrupted and an information storage device is switched to a reproduction mode immediately before the dislocation detecting address pattern 301 appears. When the dislocation detecting address pattern 301 is detected, the information storage device is set in a recording mode of the pattern for detecting dislocation in case of a dislocation detecting pattern section 303 of the track and is set in a mode to detect and record dislocation in case of the dislocation detecting pattern section 303 of the adjacent track according to the order of the dislocation detecting pattern section 303 between the adjacent track and the track.

6. 发明专利

JPH11134601A MAGNETIC HEAD AND MAGNETIC RECORDER USING THE SAME 失效
公开(公告)号：JPH11134601A
公开(公告)日：1999-05-21
申请号：JP29376497
申请日：1997-10-27
申请人： HITACHI LTD
发明人： TOMIYAMA HIROSHI , HAMAGUCHI KATSUHIKO , YAMAGUCHI TAKASHI
IPC分类号： G11B5/39 , G11B5/02
摘要： PROBLEM TO BE SOLVED: To make a track density higher without making the standardization sensitivity of the regenerative track width of head excessively large by making the head a magnetic head whose effective regenerative track width Twreff satisfies a prescribed condition with respect to the effective recording track width Twweff of a recording element. SOLUTION: In an actual head, when the interval between magnetic domain controlling films is made small in order to make the Twreff smaller, since the sensitivity of a magnetoresistive head becomes small, an error rate becomes worse than that in the assumed condition of a constant sensitivity in a region where the Twreff is small. Consequently, the error rate of 10 is secured even in a region where the Twreff is larger than a line B, that is, in a condition in which a wide write-and-narrow read is not relized. As a result, the effective track width is designed in a region where the wider write-and-narrow read is actively broken by making the Twreff smaller than a value is which 2.05×Twweff is subtracted from 5.5167.

7. 发明专利

JPH07320216A MAGNETIC DISK DEVICE 失效
公开(公告)号：JPH07320216A
公开(公告)日：1995-12-08
申请号：JP11492194
申请日：1994-05-27
申请人： HITACHI LTD
发明人： TOMIYAMA HIROSHI
IPC分类号： G11B5/09 , G11B5/02 , G11B5/39 , G11B20/18
摘要： PURPOSE:To obtain the means to accurately discriminate data by efficiently evading the thermal asperity caused from the contact between a magnetic head of the magnetic disk device and a magnetic recording medium. CONSTITUTION:Each track is read by a recording/reproducing separation type magnetic head 2 provided with a magneto-resistance-effect type head after the data area is DC erased or before the data are written. When the burst signal exceeding a certain slice level 16 is detected, the track and the sector position information are stored in a memory 21. When the recording/reproducing operation is performed, the memory 21 is referred to by a disk controller 6, and no recording/reproducing operation is executed at this position. When the used time exceeds a specified device energizing time or the number of times the head goes across the track whereon a TA is generated exceeds a prescribed number of times, the track and the sector position whereon the TA is generated are recognized again.

8. 发明专利

JPH06243432A MAGNETO RESISTIVE EFFECT TYPE MAGNETIC HEAD AND MAGNETIC DISK DEVICE UTILIZING THE SAME 失效
公开(公告)号：JPH06243432A
公开(公告)日：1994-09-02
申请号：JP2513493
申请日：1993-02-15
申请人： HITACHI LTD
发明人： TOMIYAMA HIROSHI , TSUYOSHI TOSHIAKI , KOYAMA NAOKI , YAMAMOTO KAZUHIRO , KITADA MASAHIRO
IPC分类号： G11B5/39
摘要： PURPOSE:To provide the magnetoresistive effect type magnetic head which suppresses the generation of Barkhausen noises and does not change the symmetry of reproducing waveform amplitude even if a magnetoresistive effect film is worn by sliding with recording media by extremely effectively decreasing the diamagnetic field effect of a magnetoresistive effect element by the magnetic fields leaking from the recording media and improving the high-frequency response of the magnetic head. CONSTITUTION:A nonconductive soft magnetic film 5 or conductive soft magnetic film via an insulating film is formed on the ferromagnetic magnetoresistive effect element film (described as the MR film) 2 on the surface side not facing the recording media so as to come into contact with the MR film 2. These soft magnetic films are so formed that the anisotropic easy axis thereof of parallel with the anisotropic easy axis of the magnetoresistive effect film 2. The height of the soft magnetic film for generating bias magnetic fields is increased by using the soft magnetic film 5 and a film consisting of a nonmagnetic material is formed between the soft magnetic film 5 and the soft magnetic film for generating the bias magnetic fields so as not to make magnetic exchange bonding at the time of using a soft bias method. The height of the MR film and the height of the conductor film for impressing bias are made the same by using the soft magnetic film 5 at the time of using a shunt bias method.

9. 发明专利

JP2001028111A MAGNETIC DISK DEVICE 失效
公开(公告)号：JP2001028111A
公开(公告)日：2001-01-30
申请号：JP19859799
申请日：1999-07-13
申请人： HITACHI LTD
发明人： HAMAGUCHI KATSUHIKO , ZAITSU HIDEKI , TOMIYAMA HIROSHI
IPC分类号： G11B5/596 , G11B21/10
摘要： PROBLEM TO BE SOLVED: To correct errors in positional signals of a servo area and to improve positioning precision by assigning at least one of the plural servo areas to the one containing a larger number of burst parts than other servo areas. SOLUTION: A servo area 51 has a burst part 52 consisting of four burst patterns from (A) to (D) burst, while a servo area 53 has the same burst part 52 as the servo area 51 as a first burst part and a burst part 54 as a second burst part. Among the 72 pieces of servo areas, seven pieces servo areas with sector numbers from 1 to 7 are given the structure of the servo area 53 having the second burst part 54, while the 65 pieces of servo areas with the sector numbers from 81 to 72 is given the structure of the servo area 51 having only one burst part 52. By providing the additional burst part 54 only for some of the servo areas, a consecutive writing part can be corrected which is caused at the time of recording of a servo pattern.

10. 发明专利

JPH06259714A MAGNETIC DISK DEVICE 失效
公开(公告)号：JPH06259714A
公开(公告)日：1994-09-16
申请号：JP4772793
申请日：1993-03-09
申请人： HITACHI LTD
发明人： TSUYOSHI TOSHIAKI , TOMIYAMA HIROSHI
IPC分类号： G11B5/00 , G11B5/012 , G11B5/09 , G11B5/39
摘要： PURPOSE:To appropriately and easily adjust a sense current of an MR head and to obtain the device provided with high recording density by positioning a magneto-resistance effective element to a specific zone arranged on the surface of a magnetic disk. CONSTITUTION:When the sense current is adjusted, the MR head 40 is moved to a sense current adjusting zone on the surface of the disk by driving a rotary actuator and made to the reference signal reproducing state. A reproduced waveform of the reference signal is observed as the change of the voltage between both terminals of the MR head 40. By an adjustment circuit system, a positive peak value and a negative peak value of the reproduced signal 11S are detected in peak hold circuits 14, 15 and fetched in a microcomputer 17. An analog voltage is thereby supplied to the driving circuit, and the sense current Ib is obtained. Then, the current Ib is controlled so that each positive/ negative peak value of the signal 11S becomes equal.

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