MAGNETIC TAPE DEVICE, MAGNETIC REPRODUCING METHOD, AND HEAD TRACKING SERVO METHOD

• US 20180286444A1
• Filed: 03/14/2018
• Published: 10/04/2018
• Est. Priority Date: 03/29/2017
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: KASADA, Norihito, OZAWA, Eiki
• Granted Patent: US 10,134,433 B2
• Time in Patent Office: Days
• CPC Class Codes: G11B 5/00817 on longitudinal tracks only, e.g. for serpentine format recording
• CPC Class Codes: G11B 5/584 for track following on tapes
• CPC Class Codes: G11B 5/70 on a base layer
• CPC Class Codes: G11B 5/70615 containing Fe metal or alloys G11B5/70621 takes precedence
• CPC Class Codes: G11B 5/70626 containing non-metallic substances
• CPC Class Codes: G11B 5/71 characterised by the lubricant
• CPC Class Codes: G11B 5/78 Tape carriers

Abstract

Provided is a magnetic tape device in which a magnetic tape transportation speed is equal to or lower than 18 m/sec, Ra measured regarding a surface of a magnetic layer of a magnetic tape is equal to or smaller than 2.0 nm, a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, and ΔSFD (=SFD_{25° C.}−SFD_{−190° C.}) in a longitudinal direction of the magnetic tape is equal to or smaller than 0.50, with the SFD_{25° C.} being SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25° C., and the SFD_{−19° C.} being SFD measured at a temperature of −190° C.

Claims

1. A magnetic tape device comprising:

a magnetic tape; and

a reproducing head,

wherein a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec,

the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element,

the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,

a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,

the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,

a C—

H derived C concentration calculated from a C—

H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, and

Δ

SFD in a longitudinal direction of the magnetic tape calculated by Expression 1 is equal to or smaller than 0.50,

Δ

SFD=SFD<sub>25°

C.</sub>−

SFD<sub>−

190°

C.</sub> 

 

Expression 1

in Expression 1, the SFD<sub>25°

C.</sub> is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25°

C., and the SFD<sub>−

190°

C.</sub> is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of −

190°

C.

3. The magnetic tape device according to claim 1,

wherein the Δ

SFD is 0.03 to 0.50.

6. The magnetic tape device according to claim 1,

wherein the center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.2 nm to 2.0 nm.

7. The magnetic tape device according to claim 1,

wherein the magnetic tape includes a non-magnetic layer including non-magnetic powder and a binding agent between the non-magnetic support and the magnetic layer.

2. A magnetic tape device comprising:

a magnetic tape; and

a servo head,

wherein a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec,

the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element,

the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,

the magnetic layer includes a servo pattern,

a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,

the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,

a C—

H derived C concentration calculated from a C—

H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, and

Δ

SFD in a longitudinal direction of the magnetic tape calculated by Expression 1 is equal to or smaller than 0.50,

Δ

SFD=SFD<sub>25°

C.</sub>−

SFD<sub>−

190°

C.</sub> 

 

Expression 1

in Expression 1, the SFD<sub>25°

C.</sub> is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25°

C., and the SFD<sub>−

190°

C.</sub> is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of −

190°

C.

4. A magnetic tape device comprising:

a magnetic tape; and

a reproducing head,

wherein a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec,

the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element,

the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,

a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,

the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,

a C—

H derived C concentration calculated from a C—

H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, 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 of the magnetic tape in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.

5. A magnetic tape device comprising:

a magnetic tape; and

a servo head,

wherein a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec,

the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element,

the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,

the magnetic layer includes a servo pattern,

a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,

the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,

a C—

H derived C concentration calculated from a C—

H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, 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 of the magnetic tape in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.

8. A magnetic reproducing method comprising:

reproducing information recorded on a magnetic tape by a reproducing head,

wherein a magnetic tape transportation speed during the reproducing is equal to or lower than 18 m/sec,

the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element,

the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,

a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,

the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,

a C—

H derived C concentration calculated from a C—

H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, and

Δ

SFD in a longitudinal direction of the magnetic tape calculated by Expression 1 is equal to or smaller than 0.50,

Δ

SFD=SFD<sub>25°

C.</sub>−

SFD<sub>−

190°

C.</sub> 

 

Expression 1

in Expression 1, the SFD<sub>25°

C.</sub> is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25°

C., and the SFD<sub>−

190°

C.</sub> is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of −

190°

C.

9. The magnetic reproducing method according to claim 8,

wherein the Δ

SFD is 0.03 to 0.50.

11. The magnetic reproducing method according to claim 8,

wherein the center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.2 nm to 2.0 nm.

12. The magnetic reproducing method according to claim 8,

wherein the magnetic tape includes a non-magnetic layer including non-magnetic powder and a binding agent between the non-magnetic support and the magnetic layer.

10. A magnetic reproducing method comprising:

reproducing information recorded on a magnetic tape by a reproducing head,

wherein a magnetic tape transportation speed during the reproducing is equal to or lower than 18 m/sec,

the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element,

the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,

a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,

the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,

a C—

H derived C concentration calculated from a C—

H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, 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 of the magnetic tape in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.

13. A head tracking servo method comprising:

reading a servo pattern of a magnetic layer of a magnetic tape by a servo head in a magnetic tape device,

wherein a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec,

the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element,

the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,

the magnetic layer includes the servo pattern,

a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,

the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,

a C—

H derived C concentration calculated from a C—

H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, and

Δ

SFD in a longitudinal direction of the magnetic tape calculated by Expression 1 is equal to or smaller than 0.50,

Δ

SFD=SFD<sub>25°

C.</sub>−

SFD<sub>−

190°

C.</sub> 

 

Expression 1

in Expression 1, the SFD<sub>25°

C.</sub> is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25°

C., and the SFD<sub>−

190°

C.</sub> is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of −

190°

C.

14. The head tracking servo method according to claim 13,

wherein the Δ

SFD is 0.03 to 0.50.

16. The head tracking servo method according to claim 13,

wherein the center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.2 nm to 2.0 nm.

17. The head tracking servo method according to claim 13,

wherein the magnetic tape includes a non-magnetic layer including non-magnetic powder and a binding agent between the non-magnetic support and the magnetic layer.

15. A head tracking servo method comprising:

reading a servo pattern of a magnetic layer of a magnetic tape by a servo head in a magnetic tape device,

wherein a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec,

the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element,

the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,

the magnetic layer includes the servo pattern,

a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,

the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,

a C—

H derived C concentration calculated from a C—

H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, 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 of the magnetic tape in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.