Fujifilm Assigned Five Patents

Magnetic tape having characterized magnetic layer
FujiFilm Corporation, Tokyo, Japan, has been assigned a patent (10,438,625) developed by Ozawa, Eiki, and Kasada, Norihito, Minami-ashigara, Japan, for a “magnetic tape having characterized magnetic layer.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”A magnetic tape has an Ra measured regarding the surface of the magnetic layer of less than or equal to 1.8 nm, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer of less than or equal to 0.050. The magnetic layer includes fatty acid ester. The full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before and after performing vacuum heating with respect to the magnetic tape is respectively greater than 0 nm and less than or equal to 7.0 nm, and the difference between the spacing measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape and the spacing measured before performing the vacuum heating is greater than 0 nm and less than or equal to 8.0 nm.”

The patent application was filed on February 20, 2018 (15/900,160).

Magnetic tape having characterized magnetic layer
FujiFilm Corporation, Tokyo, Japan, has been assigned a patent (10,438,624) developed by Kasada, Norihito, Minami-ashigara, Japan, for a “magnetic tape having characterized magnetic layer.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”A magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support. The center line average surface roughness Ra measured regarding the surface of the magnetic layer is less than or equal to 1.8 nm. The logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is less than or equal to 0.050. The ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the magnetic layer includes an abrasive, and the tilt cos .theta. of the ferromagnetic hexagonal ferrite powder with respect to the surface of the magnetic layer acquired by cross section observation performed using a scanning transmission electron microscope is 0.85 to 1.00.”

The patent application was filed on February 20, 2018 (15/900,106).

Magnetic tape having characterized magnetic layer
FujiFilm Corporation, Tokyo, Japan, has been assigned a patent (10,438,623) developed by Ozawa, Eiki, and Kasada, Norihito, Minami-ashigara, Japan, for a “magnetic tape having characterized magnetic layer.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”A magnetic tape has a total thickness of a non-magnetic layer and a magnetic layer of 0.60 .mu.m or smaller. The magnetic layer includes an abrasive and fatty acid ester. The percentage of a plan view maximum area of the abrasive confirmed in a region having a size of 4.3 .mu.m.times.6.3 .mu.m of the surface of the magnetic layer with respect to the total area of the region, obtained by plane observation performed by using an SEM is 0.02% or greater and less than 0.06%. The full widths at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before and after performing a vacuum heating with respect to the magnetic tape are greater than 0 nm and 7.0 nm or smaller, and the difference between spacings before and after the vacuum heating is greater than 0 nm and is 8.0 nm or smaller.”

The patent application was filed on March 14, 2018 (15/920,616).

Magnetic tape device and head tracking servo
FujiFilm Corporation, Tokyo, Japan, has been assigned a patent (10,438,622) developed by Kasada, Norihito, and Ozawa, Eiki, Minami-ashigara, Japan, for “magnetic tape device and head tracking servo method.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”The magnetic tape device includes a magnetic tape, and a servo head, in which the servo head is a TMR head, the magnetic tape includes a servo pattern in the magnetic layer, a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and a ratio, Sdc/Sac) of an average area Sdc of a magnetic cluster of the magnetic tape in a DC demagnetization state and an average area Sac of a magnetic cluster thereof in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.”

The patent application was filed on July 25, 2018 (16/044,574).

Magnetic tape having characterized back coating layer
FujiFilm Corporation, Tokyo, Japan, has been assigned a patent (10,438,621) developed by Kasada, Norihito, Minami-ashigara, Japan, for a “magnetic tape having characterized back coating layer.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”A magnetic tape includes a non-magnetic support, a magnetic layer including ferromagnetic powder and a binding agent on one surface side of the non-magnetic support, and a back coating layer including non-magnetic powder and a binding agent on the other surface side of the non-magnetic support. The thickness of the back coating layer is less than or equal to 0.30 .mu.m. The logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the back coating layer is less than or equal to 0.060. Further, the contact angle with respect to 1-bromonaphthalene measured regarding the surface of the back coating layer is 15.0.degree. to 30.0.degree.”

The patent application was filed on February 20, 2018 (15/900,334).