Patent classifications
G11B5/73937
MAGNETIC RECORDING MEDIUM, MAGNETIC RECORDING/REPRODUCING DEVICE, AND MAGNETIC RECORDING MEDIUM CARTRIDGE
A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. On the surface of the magnetic layer, recesses having a depth of 20% or more of the average thickness of the magnetic layer are formed at a ratio of 20 or more and 200 or less per 1600 μm.sup.2. On the surface of the magnetic layer, a logarithmic decay rate determined by a pendulum viscoelasticity test at a temperature of 10° C. or higher and 45° C. or lower is 0.025 or more and 0.040 or less. A difference between a maximum value of the logarithmic decay rate and a minimum value of the logarithmic decay rate is 0 or more and 0.020 or less. The squareness ratio in the perpendicular direction is 65% or more. The average thickness of the magnetic layer is 80 nm or less. The average thickness of the magnetic recording medium is 5.6 μm or less.
Magnetic recording medium having characterized magnetic layer, and magnetic recording and reproducing apparatus
The magnetic recording medium includes: a non-magnetic support; and a magnetic layer including ferromagnetic powder, in which a difference S.sub.after−S.sub.before between a spacing S.sub.after measured on a surface of the magnetic layer by optical interferometry after methyl-ethyl-ketone cleaning and a spacing S.sub.before measured on the surface of the magnetic layer by optical interferometry before methyl-ethyl-ketone cleaning is more than 0 nm and 15.0 nm or less, and the non-magnetic support is an aromatic polyamide support having a moisture absorption of 2.2% or less.
Tape-shaped magnetic recording medium including magnetic layer having recesses on a surface, magnetic recording/reproducing device, and magnetic recording medium cartridge
A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. On the surface of the magnetic layer, recesses having a depth of 20% or more of the average thickness of the magnetic layer are formed at a ratio of 20 or more and 200 or less per 1600 μm.sup.2. On the surface of the magnetic layer, a logarithmic decay rate determined by a pendulum viscoelasticity test at a temperature of 10° C. or higher and 45° C. or lower is 0.025 or more and 0.035 or less. A difference between a maximum value of the logarithmic decay rate and a minimum value of the logarithmic decay rate is 0 or more and 0.020 or less. The squareness ratio in the perpendicular direction is 65% or more. The average thickness of the magnetic layer is 80 nm or less. The average thickness of the magnetic recording medium is 5.6 μm or less.
MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING AND REPRODUCING APPARATUS
The magnetic recording medium includes: a non-magnetic support; and a magnetic layer including ferromagnetic powder, in which a difference S.sub.afterS.sub.before between a spacing S.sub.after measured on a surface of the magnetic layer by optical interferometry after methyl-ethyl-ketone cleaning and a spacing S.sub.before measured on the surface of the magnetic layer by optical interferometry before methyl-ethyl-ketone cleaning is more than 0 nm and 15.0 nm or less, and the non-magnetic support is an aromatic polyamide support having a moisture absorption of 2.2% or less.
MAGNETIC RECORDING MEDIUM, MAGNETIC TAPE CARTRIDGE, MAGNETIC RECORDING AND REPRODUCING DEVICE, AND POLYMER
The magnetic recording medium contains one or more polymers selected from the group consisting of a polymer P and a polymer Q in a portion on the non-magnetic support on the magnetic layer side. R.sup.1 represents a monovalent aromatic group or a monovalent hydrocarbon group having 6 or more carbon atoms and L.sup.1 represents a single bond or a divalent group. R.sup.2 represents a monovalent polar group and L.sup.2 represents a single bond or a divalent group. R.sup.3 represents a monovalent aromatic group or a monovalent hydrocarbon group having 6 or more carbon atoms, L.sup.3 represents a single bond or a divalent group, and R.sup.11 represents an alkyl group. R.sup.4 represents a monovalent polar group, L.sup.4 represents a single bond or a divalent group and R.sup.12 represents an alkyl group.
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