Patents by Inventor Kenmei Masuda

Kenmei Masuda has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6867938
    Abstract: A digital information reproducing apparatus using rotary heads that reproduces digital information signals recorded on a magnetic tape using magneto resistive heads installed on a rotary drum. The apparatus includes, in the fixed side of the apparatus, a magnetic tape checking circuit that checks the type of the magnetic tape; and a control signal generation circuit that generates a control signal for controlling the gain of a reproduction amplifier circuit; and on the rotary drum, a decoder circuit that identifies the control signal transmitted from the control signal generation circuit. The control signal generation circuit generates the control signal based on a checking result given by the magnetic tape checking circuit, and the decoder circuit identifies the transmitted control signal to control the gain of the reproduction amplifier circuit.
    Type: Grant
    Filed: November 20, 2002
    Date of Patent: March 15, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Shigeru Yamazaki, Kenmei Masuda
  • Patent number: 6757123
    Abstract: According to the invention, techniques for cleaning a rotary magneto-resistive head. Embodiments according to the invention are especially useful in tape drive systems, and the like. Embodiments can provide methods and apparatus for cleaning contaminant from rotary magneto-resistive heads while guarding against damage to the head from excess cleaning, and the like. Specific embodiments can control the rotational speed of a rotary magneto-resistive head in order to facilitate cleaning operations. Embodiments include a cleaning device and a control method, and are suited for use in a magneto-resistive head mounted on a rotary cylinder of a computer tape storage unit, for example, although application of the present invention is not limited to such embodiments.
    Type: Grant
    Filed: January 16, 2002
    Date of Patent: June 29, 2004
    Assignee: Exabyte Corporation
    Inventors: Kenmei Masuda, Hidekazu Takeda, Shigeru Yamazaki, Akihisa Obata, Toshio Tsuchiya, Kenkichi Inada, Kuniako Hirayama
  • Publication number: 20030223141
    Abstract: It is desirable to set an optimum bias current of an MR head in accordance with changes in MR head height, the wear difference of an MR element and the characteristics of the magnetic tape. In the present invention, test track 3 is provided in a beginning-of-tape position of a magnetic tape for setting a bias current for each of MR heads 11 and 12. A test signal is recorded on and reproduced from the test track before recording or reproducing data on/from data track 2. After detecting an error rate or a waveform asymmetry, the bias current is set in such a manner as to set the error rate or the waveform asymmetry in a predetermined range. The optimum current value is stored in memory 24, and the stored value is read out to set a bias current in a subsequent recording or reproduction.
    Type: Application
    Filed: December 5, 2002
    Publication date: December 4, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Kenmei Masuda, Shigeru Yamazaki, Hidekazu Takeda, Hideki Maruyama, Toshio Tsuchiya
  • Patent number: 6654194
    Abstract: According to the invention, techniques for cleaning a rotary magneto-resistive head. Embodiments according to the invention are especially useful in tape drive systems, and the like. Embodiments can provide methods and apparatus for cleaning contaminant from rotary magneto-resistive heads while guarding against damage to the head from excess cleaning, and the like. Specific embodiments can control the rotational speed of a rotary magneto-resistive head in order to facilitate cleaning operations. Embodiments include a cleaning device and a control method, and are suited for use in a magneto-resistive head mounted on a rotary cylinder of a computer tape storage unit, for example, although application of the present invention is not limited to such embodiments.
    Type: Grant
    Filed: August 4, 2000
    Date of Patent: November 25, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Kenmei Masuda, Hidekazu Takeda, Shigeru Yamazaki, Akihisa Obata, Toshio Tsuchiya, Kenkichi Inada, Kuniako Hirayama
  • Publication number: 20030197966
    Abstract: A digital information reproducing apparatus using rotary heads that reproduces digital information signals recorded on a magnetic tape using magneto resistive heads installed on a rotary drum. The apparatus includes, in the fixed side of the apparatus, a magnetic tape checking circuit that checks the type of the magnetic tape; and a control signal generation circuit that generates a control signal for controlling the gain of a reproduction amplifier circuit; and on the rotary drum, a decoder circuit that identifies the control signal transmitted from the control signal generation circuit. The control signal generation circuit generates the control signal based on a checking result given by the magnetic tape checking circuit, and the decoder circuit identifies the transmitted control signal to control the gain of the reproduction amplifier circuit.
    Type: Application
    Filed: November 20, 2002
    Publication date: October 23, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Shigeru Yamazaki, Kenmei Masuda
  • Publication number: 20020085302
    Abstract: According to the invention, techniques for cleaning a rotary magneto-resistive head. Embodiments according to the invention are especially useful in tape drive systems, and the like. Embodiments can provide methods and apparatus for cleaning contaminant from rotary magneto-resistive heads while guarding against damage to the head from excess cleaning, and the like. Specific embodiments can control the rotational speed of a rotary magneto-resistive head in order to facilitate cleaning operations. Embodiments include a cleaning device and a control method, and are suited for use in a magneto-resistive head mounted on a rotary cylinder of a computer tape storage unit, for example, although application of the present invention is not limited to such embodiments.
    Type: Application
    Filed: January 16, 2002
    Publication date: July 4, 2002
    Inventors: Kenmei Masuda, Hidekazu Takeda, Shigeru Yamazaki, Akihisa Obata, Toshio Tsuchiya, Kenkichi Inada, Kuniako Hirayama
  • Patent number: 6108165
    Abstract: An arrangement is designed to achieve satisfactory tape contact by setting a specific ratio for the width of a drum window and the head length of a double azimuth head. The head length L is defined as the distance from the front end of the preceding head to the back end of the succeeding head. When the drum window width W is defined as the distance of the drum window in the rotary direction, the preceding head and the succeeding head are arranged within the drum window to satisfy the relation 1.15 L.ltoreq.W.ltoreq.1.28 L. When the space S1 is defined as the distance from the front end of the preceding head to the front end of the drum window, and the space S2 is defined as the distance from the back end of the succeeding head to the back end of the drum window, the preceding head and the succeeding head are arranged within the drum window to satisfy the relation 0.075 L.ltoreq.S1.ltoreq.0.14 L and 0.075 L.ltoreq.S2.ltoreq.0.14 L.
    Type: Grant
    Filed: November 25, 1998
    Date of Patent: August 22, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Hideki Maruyama, Kenmei Masuda, Kuniaki Hirayama, Yoshio Uemura, Toshihiko Imachi, Kenkichi Inada, Toshio Tsuchiya
  • Patent number: 6078464
    Abstract: A drum base according to he invention, on which a drum of a magnetic tape recorder is mounted, comprises a substantially annular frame having a fixing surface to which the drum is fixed; at least one through hole extending through the fixing surface for allowing a screw which is to be threadably attached to a threaded hole formed in the drum to pass therethrough; and a pair of mounting surfaces provided on the fixing surface on which the drum is mounted, the mounting surfaces being located adjacent to the at least one through hole so as to have a symmetrical relationship in a circumferential direction of the annular frame with respect to the at least one through hole and within a range of a diameter dimension of the at least one through hole in a radial direction of the annular frame.
    Type: Grant
    Filed: March 27, 1996
    Date of Patent: June 20, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Hidekazu Takeda, Shinya Fujimori, Kenmei Masuda, Atsushi Inoue, Fukuyasu Abe, Hisashi Ichikawa, Masashi Ueda, Yoshiharu Yamashita, Kazuyuki Kodama
  • Patent number: 6061213
    Abstract: A magnetic tape cartridge includes a casing having a tape chamber defined therein for accommodating a reeled magnetic recording tape and, also, box arms protruding outwardly from a front wall section of the casing so as to leave a loading bay that opens upwardly, frontwardly and downwardly and is thus delimited by upwardly, frontwardly and downwardly oriented open areas. The casing includes a lid assembly for selectively concealing and exposing that portion of magnetic recording tape and including front, top and rear lids operatively linked together. The front and top lids are adapted to selectively open and close the frontwardly and upwardly oriented open areas of the loading bay, respectively, while the rear lid is positioned within the loading bay and adapted to selectively open and close a space delimited between the front and the rear lid.
    Type: Grant
    Filed: July 2, 1997
    Date of Patent: May 9, 2000
    Assignees: Hitachi Maxell, Ltd., Hitachi, Ltd.
    Inventors: Hikaru Mizutani, Mikihisa Inoue, Kenmei Masuda, Hidekazu Takeda
  • Patent number: 5978185
    Abstract: Disclosed in an arrangement to achieve satisfactory head contact by increasing contact face pressure at a head gap and to reduce the change in time of head contact performance in a double azimuth head. Heads in a portion in which a tape is slid are respectively constructed with each head having two different arcs with a radius of curvature R1 in a first area which includes a gap, and with a radius of curvature R2 in a second area which is adjacent to the first area. A transition portion P for transitioning an arc with the radius of curvature R1 and an arc with the radius of curvature R2 is located in the direction of its adjacent head based upon a contact point Q on R1 of a common tangent drawn from an arc forming a periphery of a rotating drum to a circle formed by R1. The relationship between the radiuses of curvature in two areas is set to R1>R2.
    Type: Grant
    Filed: December 23, 1996
    Date of Patent: November 2, 1999
    Assignee: Hitachi Ltd.
    Inventors: Fukuyasu Abe, Kenmei Masuda, Shinya Fujimori, Hidekazu Takeda, Atsushi Inoue, Yoshiharu Yamashita, Kuniaki Hirayama, Yoshio Uemura, Masahiko Fujishiro, Toshihiko Imachi
  • Patent number: 5812340
    Abstract: A magnetic tape recording and reproducing plug-in unit including a case with a front plate having an insertion opening through which a magnetic tape cassette is inserted, a bottom plate, a top plate, and a pair of side plates each formed with a pair of guide slots arranged for guiding the cassette to a loading position. The slide plates are attached to the side plates so as to be slidable within the case, each slide plate formed with a pair of cam slots arranged for moving the cassette to the loading position. A cassette holder is disposed inside the pair of slide plates for holding the cassette and has pins extending through the cam slots into the guide slots of the side plates. A recording and reproducing device is mounted on the bottom plate. A driving device drives the slide plates. An electronic circuit is disposed at the rear of the recording and reproducing device.
    Type: Grant
    Filed: March 11, 1997
    Date of Patent: September 22, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Tatsumi Nishijima, Kyuichirou Nagai, Kenmei Masuda, Nobuyuki Kaku
  • Patent number: 5739976
    Abstract: As a method of increasing the storage capacity of a magnetic recording and reproducing apparatus for recording and reproducing information to and from a magnetic tape in a cartridge, there is a helical scan recording method in which the magnetic tape is diagonally wound around a drum which rotates a magnetic head. With an apparatus adapted to this method, the disposition of the cartridge and the take-up reel for taking up the magnetic tape on the same plane arises a necessity of considerably bending the magnetic tape at the drum portion and, accordingly, the magnetic tape is damaged. In order to prevent the damage of the foregoing type, the tape passage surface from the cartridge to the drum and the tape passage from the drum to the take-up reel are formed by an angle at which the direction in which the magnetic tape is moved is changed due to winding of the magnetic tape around the drum so that the magnetic tape is not bent excessively.
    Type: Grant
    Filed: October 30, 1995
    Date of Patent: April 14, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Kazuo Sakai, Fumio Takeda, Taichiro Yamashita, Fujio Tajima, Takao Terayama, Tomokazu Ishii, Kooetsu Okuyama, Takayuki Munemoto, Nobuyuki Kaku, Kenmei Masuda, Shigeyuki Kobata, Fukuyasu Abe, Kenji Ogiro, Shigemitsu Higuchi
  • Patent number: 5734537
    Abstract: In a rotary head drum of a recording/reproduction apparatus, for smoothly holding a magnetic tape over a guide step provided on a lower drum to guide the magnetic tape, part of a chamfer formed in the guide step is formed as a large chamfer in which a chamfered amount is larger than that of the remaining part of the chamfer. With the provision of the large chamfer, even if the lower edge of the magnetic tape deviates from the guide step when the tape is wound over or unwound from the drum, damages of the magnetic tape can be prevented. Therefore, the position and attitude control of tape withdrawing members can be greatly simplified and the magnetic tape can always run stably while being restricted in its position by the guide step.
    Type: Grant
    Filed: May 23, 1996
    Date of Patent: March 31, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Seiji Ono, Kenmei Masuda, Hidekazu Takeda, Atsushi Inoue, Nobuo Masuoka, Noboru Katohno, Makoto Ibe, Kuniaki Hirayama, Kiyokazu Watanabe
  • Patent number: 5687047
    Abstract: A magnetic tape cartridge includes a casing having a tape chamber defined therein for accommodating a reeled magnetic recording tape and, also, box arms protruding outwardly from a front wall section of the casing so as to leave a loading bay that opens upwardly, frontwardly and downwardly and is thus delimited by upwardly, frontwardly and downwardly oriented open areas. The casing includes a lid assembly for selectively concealing and exposing that portion of magnetic recording tape and including front, top and rear lids operatively linked together. The front and top lids are adapted to selectively open and close the frontwardly and upwardly oriented open areas of the loading bay, respectively, while the rear lid is positioned within the loading bay and adapted to selectively open and close a space delimited between the front and the rear lid.
    Type: Grant
    Filed: July 10, 1996
    Date of Patent: November 11, 1997
    Assignees: Hitachi Maxell, Ltd., Hitachi, Ltd.
    Inventors: Hikaru Mizutani, Mikihisa Inoue, Kenmei Masuda, Hidekazu Takeda
  • Patent number: 5617391
    Abstract: An optical recording and reproducing system has an optical recording and reproducing head driving arrangement including an optical pick-up and has an optical recording medium provided between the recording heads. The optical recording and reproducing head is mounted on a rotating arrangement. The head scans tracks while a relative position of the recording medium and rotating arrangement is changed. Each track has an address recorded at the beginning of scanning and a hold signal at the end of scanning. The recording and reproducing heads are separated one track. The recording head makes recording while the reproducing head makes reproduction. In the recording or reproducing mode of operation, the track address is looked. If wrong, it is corrected. The hold signal is detected to operate a tracking device and focusing device. Scanning the next track is determined by the address before tracking is made for recording or reproduction.
    Type: Grant
    Filed: January 25, 1995
    Date of Patent: April 1, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Seiji Ono, Kenmei Masuda, Katsuo Konishi, Hiroyuki Nagatomo
  • Patent number: 5608585
    Abstract: A tape run control unit in the magnetic recording/reproducing apparatus is provided with a discrimination element and a control element. The discrimination element detects a stand-by time until a signal to be recorded is received in repositioning of the tape and generates a discrimination signal for discriminating the length of the stand-by time. The control element controls tape run driving unit such as a capstan motor during the reposition and controls the stop position of the tape such that a magnetic head scans the portion of the tape where no data is recorded. After completion of repositioning, furthermore, the control element works according to a discrimination signal so as to select the stop mode which involves the release of pinch roller when the stand-by time is long and to select the mode for simply stopping only the capstan when the stand-by time is short.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: March 4, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Kenmei Masuda, Kenji Ogiro, Hidefumi Goto, Sadao Hirose, Satoshi Fujino, Shinya Fujimori, Katsuhiko Izumi
  • Patent number: 5602695
    Abstract: A cassette loading mechanism for loading either a smaller tape cassette or a larger tape cassette into a recording/reproducing apparatus, having apparatus for causing the large cassette to avoid obstructions in a cassette holder during insertion of the large cassette and of enabling the stable insertion of the larger tape cassette in the cassette holder. The cassette loading mechanism has a cassette holder provided with contact members disposed so as to engage only the larger tape cassette and so as to move members provided on the cassette holder for use with the smaller tape cassette to a retracted position. The member for use with the smaller tape cassette and the contact member are formed in an integral unit to ensure the correct operation of the cassette loading mechanism.
    Type: Grant
    Filed: July 5, 1994
    Date of Patent: February 11, 1997
    Assignees: Hitachi, Ltd., Hitachi Maxell, Ltd.
    Inventors: Tatsumi Nishijima, Hidekazu Takeda, Kenmei Masuda, Hikaru Mizutani, Yoshimi Maehara
  • Patent number: 5570831
    Abstract: A tape guide device having apertures formed in two tape-winding surfaces of non-rotatable curvature portions. A tape restriction is provided at a connecting portion of the tape guide device interconnecting the curvature portions. A flange is provided on one of the curvature portions for movement along an axis thereof to adjust the height thereof. The flange has an outer diameter greater than that of the one curvature portion. The curvature portions are integrated with each other. According this, an air film is generated between the tape and the tape-winding surfaces by discharging air from the apertures, thereby reducing the friction coefficient between the tape and the tape-winding surfaces to suppress the increase of tape tension. The tape is restricted to fluctuate in the direction of width. Further, the attitude and relative positioning between the curvature portions can be secured with high precision.
    Type: Grant
    Filed: December 16, 1993
    Date of Patent: November 5, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Hidekazu Takeda, Kenmei Masuda, Nobuyuki Kaku, Tomoki Shoji, Toshihiro Koyama, Kazuo Sakai, Fumio Takeda
  • Patent number: 5497279
    Abstract: A tape cartridge is arranged so that when an upper lid of a pocket portion of the tape cartridge is in a position for opening the upper side of the pocket portion, the upper lid is positioned above an upper surface of a casing body so that a lower surface of the upper lid faces the upper surface of the casing body through a gap in which a member of a recording/reproduction apparatus for depressing the cartridge can be placed. When the upper lid is in the position for opening the upper side of the pocket, the cartridge depressing member of the recording/reproduction apparatus is placed in the gap to depress the cartridge, whereby the cartridge can be stably depressed to and mounted in a predetermined position in the recording/reproduction apparatus when the cartridge is loaded in the apparatus.
    Type: Grant
    Filed: April 8, 1994
    Date of Patent: March 5, 1996
    Assignees: Hitachi, Ltd., Hitachi Maxell Ltd.
    Inventors: Tatsumi Nishijima, Hidekazu Takeda, Kenmei Masuda, Hikaru Mizutani, Yoshimi Maehara, Kenji Ogiro
  • Patent number: 5495371
    Abstract: A magnetic recording and reproducing device and a magnetic tape library device are provided for properly recovering a function and issuing a warning when a failure of a magnetic head of the device takes place because of wear and dirt of the magnetic head. Further, a method for maintaining the magnetic head is provided. A wear sensor and a dirt sensor are prepared for sensing a wear amount of a state of dirt of the magnetic head. A head check controller operates to determine the wear amount of the magnetic head and the state of dirt based on the sensed result. In accordance with the determined result, the warning device is started for taking a precaution of preventing a head failure. As one aspect, the tape library device instructs to load the cleaning tape using a robot.
    Type: Grant
    Filed: November 29, 1993
    Date of Patent: February 27, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Takayuki Munemoto, Kazuo Sakai, Fujio Tajima, Tomokazu Ishii, Fumio Takeda, Kouetsu Okuyama, Takeshi Itoh, Shigeyuki Kobata, Kenmei Masuda, Shigemitsu Higuchi