Hitachi, Ltd.

Makoto Aihara

Moriaki Fuyama

Hiroshi Fukui

Hisashi Takano

Yutaka Sugita

Yohji Maruyama

Shinji Narishige

Kanji Kawakami

Takashi Kawabe

Hajime Aoi

Yokuo Saitoh

Tadayuki Iwakura

Hirotsugu Fukuoka

Katsuya Mitsuoka

Masanori Tanabe

Makoto Saito

Hiroshi Ikeda

Kazuo Kato

Mikio Tokuyama

Masaaki Futamoto

Kiyoshi Matsubara

Yoshihiro Shiroishi

Yoshibumi Matsuda

Masaaki Hayashi

Mikio Suzuki

Kyo Akagi

Takeshi Nakao

Nobuaki Miyakawa

Kazuhiro Nakamoto

Makoto Morijiri

Yoshinori Miyamura

Fumio Kugiya

Kazuo Nakagoshi

Kazuo Nate

Yosuke Seo

Yoji Maruyama

Masaaki Sano

Sadanori Nagaike

Teruyoshi Higashiya

Takayuki Munemoto

Tokuho Takagaki

Eiji Ashida

Masatoshi Tsuchiya

Shunichiro Kuwatsuka

Yukihiro Isono

Hideki Yamazaki

Hideki Sonobe

Tetsuji Higashijima

Yoshikazu Tsuji

Mitsuo Suda

Shuji Sudo

Kouji Takeshita

Three pads are disposed on the surface of a magnetic head facing to a storage medium and are brought into contact with the surface of the storage medium through a lubricant layer. The total of areas of the three pads is equal to or larger than 0.0001 mm.sup.2 and equal to or smaller than 0.02 mm.sup.2 and the height of the pads is equal to or higher than 5 .mu.m and equal to or lower than 100 .mu.m. Two pads of the three pads include tapers formed in the front thereof and are disposed in a forward position in a relative movement direction to the storage medium and one remaining pad is disposed in a backward position. The total of areas of the two pads in the forward position is set to be narrower than an area of the pad in the backward position. A writing and reading function unit is provided in the pad in the backward position.

Magnetic storage apparatus having a head with sliding pads

Magnetic head with a magnetic pole sandwiched between conductive

A magnetic storage apparatus includes a magnetic head having sliding front and rear pads on its sliding surface. The front pads are tapered toward their front ends and the height of the front pads are higher than the height of the rear pad. The tapered front pads are coated with a thin film. The magnetic pad is provided with a total of three pads, two pads on its front side and one pad on its rear side. The sum area of the pads is within a range of 0.0003 to 0.02 mm.sup.2. A recording and reproducing operation is performed with the front pads and the rear pad concurrently kept in contact sliding with the surface of a recording medium. A reliable contact sliding is thus performed with the pads kept in contact with the recording medium. The magnetic head reliably operates with its recording and reproducing component kept in close vicinity with the recording medium. Therefore, a reliable magnetic head and a magnetic storage apparatus employing it are provided.

Magnetic head and slider configuration for contact recording having a

A magnetic disc apparatus has a large recording density of 120 megabits per square inch or more, and defines a relationship among a pole thickness (Pt) of thin-film magnetic heads disposed in the magnetic disc apparatus, and a saturation flux density (Bs) of cores of the heads and a recording wavelength (.lambda.) for the thin film magnetic discs have a coercivity of 1800 Oe or more, wherein a levitation space between the head and the disc is 0.15 .mu.m or less.

Large capacity magnetic disc apparatus with a particular relationship

A magnetic disc unit has a thin film magnetic head in which a lower magnetic core and an upper magnetic core form a magnetic circuit. The upper magnetic core is constructed by magnetic films having at least two layers. A saturation magnetic flux density of the inside magnetic film, of the magnetic films having at least two layers, facing a magnetic gap of the magnetic circuit is larger than that of the outside magnetic films of the upper magnetic core and the lower magnetic core.

Magnetic disc unit having a plurality of magnetic heads which include

A method and device of head positioning in an information recording/reading device in which a magnetic recording medium with data tracks for recording information thereon is provided and a magnetic head is positioned on the data track to record/read out the information, wherein a data signal is recorded in the data recording layer of said recording medium, a servo signal is recorded in the servo signal recording layer located below said data signal recording layer, said data signal is read out using a data magnetic head whereas said servo signal is read out using a servo magnetic head, and the frequency of said servo signal is within the range of the gap-null frequency of said data magnetic head whereas the frequency of said data signal is within the range of the gap-null frequency of said servo magnetic head, and said magnetic head is positioned on the data track on the basis of said servo signal. A method and device of head positioning in an information recording/reading device in which a magnetic recording medium with data tracks for recording information thereon is provided and a magnetic head is positioned on the data track to record/read out the information, wherein the data tracks are discrete tracks in which adjacent data tracks are separated by a groove located therebetween, a data signal is recorded on the data track of said recording medium, a servo signal is recorded on the servo tracks of grooves between said adjacent data tracks, and said magnetic head is positioned on the data track on the basis of said servo signal.

Method of head positioning and magnetic recording disk drive using the

A magnetic disc apparatus includes a magnetic disc for recording information; a thin film magnetic head including a magnetic pole structure having an upper magnetic pole tip and a lower magnetic pole tip arranged to provide a magnetic gap at respective end portions thereof for writing and reading information in and from the magnetic disc; a device for rotating the magnetic disc; and a device for positioning the thin film magnetic head; the upper and lower magnetic pole tips having different contours at the respective end portions as viewed from a side confronting the magnetic disc wherein the difference (.DELTA.CW in .mu.m) in the width, along the magnetic gap, of the upper magnetic pole tip and the width, along the magnetic gap, of the lower magnetic pole tip satisfies the relation

Magnetic disc apparatus with thin film head suitable for high-density

DC bias currents are applied to a conducting wire of a thin film magnetic head to be inspected. When the DC bias currents (I.sub.0, I.sub.1, I.sub.2) are supplied to the conducting wire, the impedances (Z.sub.0, Z.sub.1, Z.sub.2) corresponding to the DC bias currents are measured. When a ratio (.vertline.Z.sub.1 -Z.sub.0 .vertline./.vertline.Z.sub.2 -Z.sub.0 .vertline.) corresponding to an overwrite characteristic (OW) reaches to a predetermined value by lapping tip portions of an upper magnetic layer and a lower magnetic layer of the magnetic head, the lapping process of the magnetic head is finished.

Method for making a thin film magnetic head

An analog data acquisition device fetches a plurality of analog data by a multiplexer in time-division, compares the analog data fetched with a reference value applied from a digital-to-analog converter by a two-input comparator, and produces the result of comparison to a data bus. The result of comparison is also applied to a successive approximation register where the analong-to-digital conversion is effected by successively changing the digital data to the digital-to-analog converter, and the digital data converted is read out onto the data bus. The digital data applied to the digital-to-analog converter is either the output from the successive approximation register or the output from the reference register loaded through the data bus, in accordance with the contents of the control register loaded through the data bus. Thus, in which mode the device operates, in the comparing mode or in the analog-to-digital conversion mode, is selected by the control register.

Analog data acquisition device

Growing community of inventors

Katsuta, Japan

Makoto Aihara