US 11,922,981 B2
Magnetic tape device
Norihito Kasada, Minamiashigara (JP)
Assigned to FUJIFILM Corporation, Tokyo (JP)
Filed by FUJIFILM Corporation, Tokyo (JP)
Filed on Jul. 25, 2022, as Appl. No. 17/872,464.
Claims priority of application No. 2021-121715 (JP), filed on Jul. 26, 2021; and application No. 2021-202748 (JP), filed on Dec. 14, 2021.
Prior Publication US 2023/0039477 A1, Feb. 9, 2023
Int. Cl. G11B 5/48 (2006.01); G11B 5/008 (2006.01)
CPC G11B 5/4893 (2013.01) [G11B 5/00821 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A magnetic tape device comprising:
a medium; and a magnetic head,
wherein
the medium is a magnetic tape,
the magnetic head includes a module including an element array including a plurality of magnetic head elements between a pair of servo signal reading elements,
the magnetic tape device changes an angle θ formed by an axis of the element array with respect to a width direction of the magnetic tape during running of the magnetic tape in the magnetic tape device,
the magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder,
the magnetic layer includes a plurality of servo bands,
in a case where storage in an environment of a temperature of 23° C. and relative humidity of 50% for 12 hours and storage in an environment of a temperature of 32° C. and relative humidity of 55% for 12 hours are defined as one cycle, a maximum value of an absolute value of a difference between a servo band spacing obtained before the storage and a servo band spacing obtained after the storage of N cycles is defined as A, a unit of A is μm, and N is set to 1, 2, 3, 4, or 5, a medium life calculated by a linear function of A and a logarithm loge T of T, that are derived from a value of A and a value of the logarithm loge T of total storage time T of the storage of N cycles is 5 years or longer,
the medium life is the total storage time T when A satisfies Equation a:
A=1.5−B+C,  (Equation a)
the B is a value calculated by multiplying a difference between a maximum value and a minimum value of servo band spacings obtained
in each of the following five environments of
a temperature of 16° C. and relative humidity of 20%,
a temperature of 16° C. and relative humidity of 80%,
a temperature of 26° C. and relative humidity of 80%,
a temperature of 32° C. and relative humidity of 20%, and
a temperature of 32° C. and relative humidity of 55%,
by ½, and a unit is μm, and
the C is a value calculated by
C=L{cos(θinitial−Δθ)−cos(θinitial+Δθ)} and
a unit is μm,
the L is a distance between the pair of servo signal reading elements and a unit is μm, and
in a case where the angle θ at start of the running of the magnetic tape is defined as θinitial,
a maximum value of the angle θ during the running of the magnetic tape is defined as θmax, and a minimum value thereof is defined as θmin, and
the Δθ is a greater value between values calculated by
Δθmax=θmax−θinitial and
Δθmin=θinitial−θmin.