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    MANUFACTURE OF MAGNETIC RECORDING MEDIUM
    4.
    发明专利
    MANUFACTURE OF MAGNETIC RECORDING MEDIUM 失效

    公开(公告)号：JPH02292725A

    公开(公告)日：1990-12-04

    申请号：JP9418190

    申请日：1990-04-11

    Applicant: BASF AG

    Inventor： HORUSUTO PURATSUTSU ,  PEETAA ENGERUHARUTO ,  FURIIDORITSUHI ZOMAAMAN ,  ARUBERUTO KOORU ,  YURUGEN KURAUSUMAN ,  RAINHORUTO BAURU ,  PEETAA HAIRUMAN ,  HERUMAN RORAA

    IPC: G11B5/84 ,  G11B5/842

    Abstract: PURPOSE: To improve the recording properties of a magnetic recording medium by producing a dispersion in a mixing and pulverizing machine filled with pulverizing balls having a specific diameter and density. CONSTITUTION: The dispersion is produced in the mixing and pulverizing machine filled with the pulverizing balls having a diameter of 0.2 to 3.0mm and a density of 3.6 to 3.9g/cm . The dispersion is post-treated in a ball mill including pulverizing balls having a diameter larger than 2.0mm and a density larger than 4.2g/cm . The dispersion is so produced that the viscosity of the resulted dispersion, measured at 25 deg.C is at least 50mPas and that the added particulate magnetic material has at least 14m /g as the surface layer measured by a BET method. Consequently, the stable dispersion is produced without increasing a dispersant ratio and/or stabilizer ratio by using the known effective dispersion assembly. As a result, the magnetic properties are intrinsically improved and the recording properties of the resulted magnetic recording medium are improved.

    METHOD OF MEASURING THICKNESS OF MAGNETIC TAPE
    5.
    发明专利
    METHOD OF MEASURING THICKNESS OF MAGNETIC TAPE 失效

    公开(公告)号：JPH0283408A

    公开(公告)日：1990-03-23

    申请号：JP21532988

    申请日：1988-08-31

    Applicant: BASF AG

    Inventor： RAINHORUTO BAURU ,  YURUGEN KURAUSUMAN

    IPC: G01B21/08 ,  G01B7/06 ,  G11B5/84

    Abstract: PURPOSE: To measure the thickness of a magnetic tape while it is wound in roll by calculating the rotation per unit time of the hub while the magnetic tape is taken up, measuring the length of wound tape and calculating the tape thickness using a specified mathematical relational expression. CONSTITUTION: During winding of a magnetic tape, rotation per unit time nB of a hub of radius r0 is calculated, and by counting pulses of a tape length measuring means, a wound tape length 1B is decided. Then, the difference between the tape thickness directly measured by a thickness measuring means and the decided tape thickness is calibrated utilizing a tape roll diameter on the hub after wound and tape winding times. Since the latter tape thickness varies depending on operation conditions of loading devices such as tape's physical characteristics such as surface roughness, tape thickness (d) is calculated with a microprocessor using a mathematical relational expression, d=1Ba/ n B-2r0 /nB, and the tape thickness is used for monitoring/processing while compared to a tolerant error limit.

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