Hitachi, Ltd.

Hitachi Computer Peripherals Co., Ltd.

Yoshihiro Moribe

Mikio Takahashi

Kazuo Nakagoshi

Osamu Beppu

Akira Chuma

Hideo Maekawa

Toshiaki Tsuyoshi

Yukitaka Hayashi

Masahiro Mitamura

Sumio Obata

Yasuo Yamamoto

Nobukuni Ohkubo

Shigeo Nakamura

Masafumi Nozawa

Kazuhisa Shiraishi

Hiroshi Tsuchiya

Kiyotake Kumazawa

Asao Sasamoto

Toshio Shiono

Yoshiyuki Hirano

Akio Takatsuka

Haruhiko Hosokawa

Chikayuki Sogabe

Tetsuji Kameoka

Kunitsugu Tsukui

Masataka Fujii

Takaaki Abo

Tetsji Kameoka

Noriaki Minamide

Noriaki Miniamide

Increased memory capacity for a magnetic disk device is realized without degrading information error rate, by making the number of sectors at a given circumference of the disk variable in accordance with a radial direction of a disk. The number of sectors is made variable by deciding a predetermined information error rate from a ratio of reproduced signal output to noises of head, disk and amplifier at a maximum recording and reproducing frequency at a certain radial position along a disk.

Method and apparatus for optimizing the recording and reproducing of

In a record/reproduce apparatus, medium defects in magnetic disks are avoided without considerably losing record areas. In a record or reproduce mode, the plurality of magnetic disks are accessed in parallel by a plurality of magnetic heads and a plurality of record circuits or reproduce circuits. Regarding the record areas where only one of the magnetic disks has the medium defect, a control circuit controls a head change-over circuit so that a record area in a spare magnetic disk may be accessed by a spare magnetic head instead of the defective record area. Besides, regarding the record areas where two or more of the magnetic disks have the medium defects, the control circuit operates so that spare record areas in the two or more magnetic disks may be accessed instead of the defective record areas.

Method of avoiding medium defects in record/reproduce apparatus

A housing for an information recording and reproducing apparatus is adapted for increased storage capacity and an increased operating speed by placing a relatively larger number of relatively smaller magnetic disks each having a relatively smaller mass and a relatively smaller recording and reproducing surface in an enclosure and housing the enclosure for a relatively larger magnetic disc in a box-like frame. A shock absorbing device is disposed between the enclosure and the box-like frame to absorb shock. A circuit assembly for controlling the operation of recording and reproducing is disposed outside the enclosure and between the frame and the enclosure.

Mounting structure for information recording and reproducing apparatus

A favorable balance of mass and strength is provided by the truss type beam formed through the use of triangular apertures in the head arm, which further can be arranged to provide a greater leading edge beam strength than trailing edge beam strength. With increased density of data and correspondingly decreased flying height, favorable results are obtained by making the outermost yaw angle greater than the innermost yaw angle. Mass unbalance can be corrected by shifting the coil position.

Magnetic head mounting arm having asymmetrical configuration

In a rotary actuator including a voice coil motor having a coil fitted to the other end portion of a carriage fixed to a rotary shaft and having a load at one of the end portions thereof, the rotary actuator of the present invention is characterized in that the rotation on the coil side and the rotation on the load side with respect to the rotary shaft are balanced. The weight of the coil is adjusted by forming the coil by at least two kinds of coil wires having different specific gravities, and where a plurality of coils are disposed on the outer side of the rotary shaft, the weight of the coil on the load side is made smaller than that of the coil on the opposite side.

Rotary actuator

A disk drive housing structure has a rotating disk for recording information and a transducer adapted to write and read information on and from the disk. The structure further includes a positioning system having at least an arm to which the transducer is fixed and which is adapted to selectively position the transducer along the radial direction of the disk transducer by turning the arm. The structure also includes a member on which the disk, transducer and positioning system are mounted, wherein the mounting member includes a first housing which supports thereon both ends of a rotary shaft of the recording medium and both ends of a rotary shaft of the positioning system, and which has a first aperture part. The first housing further includes a second aperture part through which the disk and the rotary shaft supporting the disk are inserted and to which a supporting member for the rotary shaft of the recording medium is fixed.

Disk drive housing structure

A method of adjusting the position of a magnetic head in a magnetic head positioning mechanism positions the magnetic head at a target track on a magnetic disk. Since a floppy disk system is so designed as to make a floppy disk replaceable, it is necessary to adjust accurately the position of the magnetic head from the position of a spindle. According to the present invention, the position of the magnetic head is adjusted by the method wherein the displacement of an amount of deviation from a prescribed track in the magnetic head positioning mechanism is calculated beforehand, the amount of deviation is sampled subsequently by moving the magnetic head, this sampled amount of deviation is compared with the aforesaid calculated displacement to know the maximum and minimum values of the amounts of deviation on the track of movement of the magnetic head, and the adjustment is implemented on the basis of these values.

Method for adjustably positioning a transducer for a disc drive

A method of first erasing the full width of a recording track using an erase core before recording data into a flexible disk and then writing the new data into the erased area using a read/write core, and an apparatus for effecting the same are disclosed. The erasure by the erase core is done in an AC manner. A gap pattern used to form a gap area is written by the read/write core into a portion of the erased area where no valid data has been written.

Apparatus for and method of writing/reading data into/from a flexible

A method and apparatus for moving a moving member of a positioning mechanism to a target position by means of a stepper motor as a driver. The method and apparatus alleviate the positioning error attributable to the hysteresis of the stepper motor, which is inherent in stepper motor drive systems, by controlling the oscillation damping condition when the stepper motor has entered a damped oscillation phase in the vicinity to the target positon. The damping condition is controlled by varying the solid friction factor of the mechanism or the drawback torque constant of the stepper motor.

Positioning method and apparatus therefor

First and second magnetic heads, or magnetic head sliders containing these heads, which are brought into contact with a magnetic disc on its both sides so as to record and reproduce information signals, are respectively supported by first and second swing arms. The first and second swing arms are respectively supported by first and second elastic bodies. The swing arms are respectively provided with first and second adjusting screws for adjusting the movable range of the swing arms. The first adjusting screw operates to adjust the pressure of a first spring supported by the first arm and the position of the first magnetic head. The second adjusting screw operates to locate the associated second magnetic head to a position which is adjusted to the thus-adjusted position of the first magnetic head.

Magnetic head assembly

In a disk unit having a rotating mechanism to rotate the disk by pinching the disk at both sides, and a loading mechanism to bring a read-write head into contact with the disk, a method for driving the disk includes the steps in which, at the time of recording and reproduction, the rotating mechanism and the loading mechanism are actuated simultaneously, and when the recording and reproduction are completed, the rotating mechanism is stopped simultaneously with release of the loading mechanism, or after the lapse of a predetermined time from the release.

Method and apparatus for driving a disk

A magnetic disc head positioning system using a stepper motor eliminates positioning errors due to different approach directions and distances to a target track position through a drive control of temporarily stopping the head at a position immediately preceding or following the target track depending on the approach direction and, thereafter, moving the head from this position to the target track with a constant transient response. The head is brought to the temporary stop position by utilizing the overshooting response of the stepper motor so as to minimize the positioning time.

Control method and apparatus for positioning servo system

A head loading system including a head support mechanism supporting heads for at least reproducing information in juxtaposed relation to a recording medium, and a loading actuator driving the head support mechanism to move the heads toward and away from the recording medium. The loading actuator include motion converting arrangement for converting a linear motion of a solenoid into a rotary motion which is capable of increasing the amount of motion when the linear motion is converted into the rotary motion, thereby enabling the loading actuator to drive the heads with a small amount of linear motion. The motion converting arrangement includes a rotary member connected to a plunger of the solenoid and formed with grooves, a frame juxtaposed against the rotary member and formed with grooves and a bearing fitted between the grooves. The linear motion of the plunger is converted into a rotary motion of the rotary member by the action of the bearing performed in cooperation with the grooves.

Head loading system

A floppy disk driver intended to protect the disk center hole from damage when the disk is mounted. The arrangement includes a speed detection circuit for detecting a relatively low rotational speed of the disk and a control circuit for speeding up the disk to a higher rotational speed for the read/write operation in response to the detection of the lower disk speed, whereby the disk is protected from damage by being rotated at the lower speed when its center hole is held between the collet and spindle.

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Chigasaki, Japan

Yoshihiro Moribe