Patent classifications
G11B5/70678
Magnetic tape, magnetic tape cartridge, and magnetic tape apparatus
The magnetic tape includes a non-magnetic support; and a magnetic layer in which the magnetic layer has a timing-based servo pattern, an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference between a value L.sub.99.9 of a cumulative distribution function of 99.9% and a value L.sub.0.1 of a cumulative distribution function of 0.1% in a position deviation width from an ideal shape of the magnetic tape in a longitudinal direction is 180 nm or less, and a difference between a spacing S.sub.after measured on a surface of the magnetic layer by an optical interferometry after methyl-ethyl-ketone cleaning and a spacing S.sub.before measured on the surface of the magnetic layer by an optical interferometry before methyl-ethyl-ketone cleaning is greater than 0 nm and 15.0 nm or less.
Magnetic tape, magnetic tape cartridge, and magnetic tape apparatus
The magnetic tape includes a non-magnetic support and a magnetic layer, in which an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference between a value L.sub.99.9 of a cumulative distribution function of 99.9% and a value L.sub.0.1 of a cumulative distribution function of 0.1% in a position deviation width from an ideal shape of the magnetic tape in a longitudinal direction is 180 nm or less, and in which a difference between a spacing S.sub.after measured on a surface of the magnetic layer by an optical interferometry after ethanol cleaning and a spacing S.sub.before measured on the surface of the magnetic layer by an optical interferometry before ethanol cleaning is greater than 0 nm and 6.0 nm or less.
Magnetic tape having characterized back coating layer, magnetic tape cartridge, and magnetic recording and reproducing apparatus
The magnetic tape includes: a non-magnetic support; a magnetic layer that includes ferromagnetic powder on one surface side of the non-magnetic support; and a back coating layer that includes non-magnetic powder on the other surface side of the non-magnetic support, in which the ferromagnetic powder is ferromagnetic powder selected from the group consisting of hexagonal strontium ferrite powder and ε-iron oxide powder, and the number of protrusions having a height of 50 nm or more and less than 75 nm on a surface of the back coating layer is 700 pieces/6400 μm.sup.2 or less.
MAGNETIC RECORDING MEDIUM AND CARTRIDGE
A magnetic recording medium is a tape-shaped magnetic recording medium, including: a substrate; an underlayer provided on the substrate; and a magnetic layer provided on the underlayer. The substrate contains polyester, each of the underlayer and the magnetic layer contains a lubricant, the magnetic layer has a surface on which a large number of holes is provided, the arithmetic average roughness Ra of the surface is 2.5 nm or less, a BET specific surface area of the entire magnetic recording medium measured in a state where the magnetic recording medium has been washed and dried is 3.5 m.sup.2/g or more and 7.0 m.sup.2/g or less, a squareness ratio of the magnetic layer in a vertical direction is 65% or more, an average thickness of the magnetic layer is 80 nm or less, an average thickness of the magnetic recording medium is 5.6 μm or less, and a servo pattern is recorded on the magnetic layer and a statistical value δ.sub.SW indicating a non-linearity of the servo pattern is 24 nm or less.
Magnetic recording and reproducing device
The magnetic recording and reproducing device includes a magnetic recording medium, a recording element, and a reproducing element. The recording element is an inductive recording element having a first magnetic pole which generates a magnetic field, and a second magnetic pole which is spaced apart from the first magnetic pole with a write gap interposed therebetween, a tip width of the first magnetic pole is substantially the same as a tip width of the second magnetic pole, and a reproducing element width of the reproducing element is 0.5 μm to 0.8 μm. The magnetic recording medium has a non-magnetic support, and a magnetic layer containing a ferromagnetic powder, and the number of recesses, which are present in a surface of the magnetic layer and have an equivalent circle diameter of 0.20 μm to 0.50 μm, is 10 to 500 per area of 40 μm×40 μm.
MAGNETIC RECORDING MEDIUM
An object is to provide a magnetic recording medium having excellent traveling stability and a thin total thickness.
The present technology provides a tape-shaped magnetic recording medium including: a magnetic layer; an underlayer; a base layer; and a back layer, in which a surface on a side of the magnetic layer has a kurtosis of 3.0 or more, a surface on a side of the back layer has a kurtosis of 2.0 or more, the surface on the magnetic layer side has arithmetic average roughness R.sub.a of 2.5 nm or less, the base layer includes a polyester as a main component, the magnetic recording medium has an average thickness t.sub.T of 5.6 μm or less, the magnetic recording medium includes a lubricant, the lubricant includes a fatty acid and a fatty acid ester, and a mass ratio between the fatty acid and the fatty acid ester extracted with hexane satisfies fatty acid/fatty acid ester ≤0.6, and the magnetic recording medium has pores, and the pores have an average diameter of 6 nm or more and 11 nm or less when the diameters of the pores are measured in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried.
MAGNETIC RECORDING MEDIUM
A magnetic recording medium is a magnetic recording medium in the form of a tape and includes a substrate, a foundation layer provided on the substrate, and a magnetic layer provided on the foundation layer and containing a magnetic powder. The foundation layer and the magnetic layer each contain a lubricant. A squareness ratio of the magnetic layer in a perpendicular direction is equal to or higher than 65%, an average thickness of the magnetic recording medium is equal to or smaller than 5.6 μm, a plurality of recessed portions each having a depth corresponding to 20% or higher of the average thickness of the magnetic layer is provided on a surface of the magnetic layer, and the number of the recessed portions per unit area of 1,600 μm.sup.2 of the surface of the magnetic layer is equal to or greater than 20 and equal to or smaller than 200, and an amount of exudation of the lubricant per unit region of 12.5 μm×9.3 μm on the surface of the magnetic layer in a vacuum is equal to or greater than 3.0 μm.sup.2 and equal to or smaller than 6.5 μm.sup.2.
Magnetic recording medium
A tape-shaped magnetic recording medium is provided with a base, an underlayer provided on the base, and a magnetic layer provided on the underlayer including magnetic powder including hexagonal ferrite. The underlayer and the magnetic layer include lubricant. The magnetic layer includes a surface provided with a large number of holes, and arithmetic average roughness Ra of the surface is 2.5 nm or smaller. A BET specific surface area of a whole of the magnetic recording medium in a state in which the lubricant is removed is 3.5 m.sup.2/mg or larger. A square ratio in a vertical direction is 65% or larger, an average thickness of the magnetic layer is 90 nm or smaller, and an average thickness of the magnetic recording medium is 5.6 μm or smaller.
MAGNETIC TAPE HAVING CHARACTERIZED PSD RATIO, MAGNETIC TAPE CARTRIDGE, AND MAGNETIC RECORDING AND REPRODUCING APPARATUS
The magnetic tape includes a non-magnetic support, a magnetic layer that includes ferromagnetic powder having an average particle volume of 2,500 nm.sup.3 or less on one surface side of the non-magnetic support, and a back coating layer that includes non-magnetic powder on the other surface side of the non-magnetic support, in which the ferromagnetic powder is ferromagnetic powder selected from the group consisting of hexagonal ferrite powder and ε-iron oxide powder, and a ratio (PSD.sub.5μm-PSDmag/PSD.sub.10μm-PSDbc) of the magnetic layer and the back coating layer is in a range of 0.0050 to 0.20. A magnetic tape cartridge and a magnetic recording and reproducing apparatus include the magnetic tape.
MAGNETIC RECORDING MEDIUM, MAGNETIC TAPE CARTRIDGE, AND MAGNETIC RECORDING AND REPRODUCING DEVICE
Provided are: a magnetic recording medium including a non-magnetic support and a magnetic layer containing a ferromagnetic powder, in which the ferromagnetic powder is an ε-iron oxide powder, a vertical magnetization amount Φm per unit area of the magnetic recording medium is 5 G.Math.μm or more and 100 G.Math.μm or less at a measurement temperature of 25° C., and an inclination of Φm obtained from Φm at a measurement temperature of 10° C., Φm at a measurement temperature of 25° C., and Φm at a measurement temperature of 40° C. is −0.20 G.Math.μm/° C. or more and −0.03 G.Math.μm/° C. or less; a magnetic tape cartridge including the magnetic recording medium which is a magnetic tape; and a magnetic recording and reproducing device including the magnetic recording medium.