Multiple-layer backcoating for magnetic tape

• US 20030059649A1
• Filed: 08/16/2002
• Published: 03/27/2003
• Est. Priority Date: 08/17/1999
• Status: Abandoned Application

• Current Assignee: Quantum Corporation (Chi Ko Investment Co., Ltd.)
• Original Assignee: Quantum Corporation (Chi Ko Investment Co., Ltd.)
• Inventors: Choe, Geon, Seng, Daravuth, Mallick, Satya, Saliba, George A.
• Application Number:
  US10/222,420
• Publication Number:
  US 20030059649A1
• Time in Patent Office: Days
• US Class Current: 428/694BB
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G11B 5/7358 specially adapted for achieving a specific property, e.g. average roughness [Ra]
• CPC Class Codes: G11B 5/743 Patterned record carriers, wherein the magnetic recording layer is patterned into magnetic isolated data islands, e.g. discrete tracks
• CPC Class Codes: G11B 5/78 Tape carriers
• CPC Class Codes: G11B 5/8404 manufacturing base layers
• CPC Class Codes: Y10T 428/24479 including variation in thickness
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles

Abstract

A magnetic tape comprises a substrate having on one side thereof a magnetic layer serving as a recording surface, and on the other side thereof at least two layers containing inorganic particles which serve as a non-recording surface, wherein said magnetic tape has a region on the side of the non-recording surface along the longitudinal direction of the tape in which a regular pattern for servo tracking having different optical properties from the other major region of the side of the non-recording surface is or can be formed. The layers on the non-recording surface are characterized in that the inorganic particles in the outermost layer are larger than the inorganic particles in the underlying layer(s).

Claims

1. A magnetic tape comprising a substrate having disposed on opposite sides thereof a recording surface and a non-recording surface, wherein the recording surface comprises a magnetic layer, and the non-recording surface comprises at least two layers containing inorganic particles, said two layers comprising a first outer layer and a second inner layer, wherein the first layer comprises inorganic particles of a size sufficient to provide improved tape runnability and conductivity and to reduce reflectance, and the inner layer comprises inorganic particles of a size different from the inorganic particles in the first layer, wherein the size of the inorganic particles in the second layer provide improved servo cutting quality to the tape.

2. The magnetic tape of claim 1 wherein the inorganic particles in the first layer are larger than the inorganic particles in the second layer.

3. The magnetic tape of claim 1 wherein the non-recording surface has disposed along a longitudinal direction of the tape a regular pattern for servo tracking, said pattern having optical properties different from the non-patterned region of the non-recording surface.

4. The magnetic tape of claim 1 wherein said optical properties comprises an absorbance, reflectance or transmission of light, and the difference between said pattern and the non-patterned region of the non-recording surface in absorbance, reflectance or transmission of light having a prescribed wavelength used for servo tracking is about 10% or more.

5. The magnetic tape of claim 1, wherein the inorganic particles are carbon black particles.

6. The magnetic tape of claim 1 wherein the size of the particles in the first outer layer is in the range of from about 0.05 μ

m to about 0.08 μ

m.

7. The magnetic tape of claim 1 wherein the size of the particles in the second inner layer is in the range of from about 0.02 μ

m to about 0.035 μ

m.

8. The magnetic tape of claim 1 wherein said magnetic tape further comprises a layer of a metal or a metal alloy having a low melting point disposed between said substrate and said second layer, and a servo tracking pattern comprising depressions is formed in said metal or alloy layer.

9. The magnetic tape of claim 8 wherein said servo tracking pattern has a width of from about 0.1 to about 30 μ

m and a depth of from about ⅓

of the thickness of said metal or alloy layer up to the entire thickness of said thin layer.

10. A magnetic tape comprising a substrate having disposed on opposite sides thereof a recording surface, and a non-recording surface, wherein the recording surface comprises a magnetic layer, and the non-recording surface comprises at least two layers containing inorganic particles, wherein said magnetic tape has a regular pattern for servo tracking on the non-recording surface along the longitudinal direction of the tape which pattern has optical properties which differ from the non-patterned region of the non-recording surface.

11. A magnetic tape comprising a substrate having on one side thereof a recording surface comprising a magnetic layer, and on the other side thereof a backcoat system of at least two layers comprising a first outer layer and a second inner layer containing carbon black particles, wherein said backcoat system has disposed along the longitudinal direction of the tape a regular pattern for servo tracking having optical properties different from the non-patterned region.

12. A magnetic tape according to claim 11, wherein

the regular pattern comprises a repeating pattern of marks extending along substantially the length of the tape.

13. The magnetic tape according to claim 11, wherein

the regular pattern comprises a repeating pattern of marks extending transversely to an axis substantially perpendicular to the longitudinal edge of the tape.

14. A method of making a recording tape, comprising the steps of

providing a substrate having disposed on one side thereof a magnetic layer serving as a recording surface and on the other side thereof a backcoating system comprising a first outer layer and a second inner layer containing inorganic particles, and

directing a beam of light at said backcoat layer thereby to form an optically detectable depression in said backcoat layer.

15. A method according to claim 14, further comprising the step of forming a plurality of depressions in the layer.