Magnetic Tape Back Coating Surface Roughness Control

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Solution Overview

Problem

Magnetic tapes with increased surface smoothness of the back coating layer experience deterioration in running stability due to temperature changes from high to low temperatures under low humidity conditions, leading to signal drop-outs and increased error rates.

Innovation Solution

A magnetic tape with a back coating layer having a center line average surface roughness of 7.0 nm or less and a spacing difference of 0 to 15.0 nm before and after ethanol cleaning, which helps maintain stability by controlling the amount of organic components on the surface and preventing contact instability with drive constituents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the surface smoothness of the back coating layer is increased to prevent set-off, then drop-out is prevented, but running stability deteriorates under temperature change from high to low temperature under low humidity

Engineering Contradiction:
Improvedrop-out preventionVSAvoidrunning stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention changes the surface roughness parameter of the back coating layer to a specific range (Ra: 3.0-7.0 nm) and controls the organic component content through the spacing difference parameter (Safter-Sbefore: 1.0-15.0 nm). This parameter optimization resolves the contradiction by finding the optimal balance point where both set-off prevention and running stability are maintained under temperature variations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The back coating layer is formulated as a composite material containing non-magnetic powder and binding agent with controlled organic components. The specific composition and spacing difference parameters create a composite structure that simultaneously provides surface smoothness for set-off prevention and maintains running stability under temperature changes.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the surface smoothness of the back coating layer is increased to prevent set-off, then drop-out is prevented, but contact instability with drive constituents occurs under temperature change

Engineering Contradiction:
Improvedrop-out preventionVSAvoidcontact stability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention optimizes the surface roughness parameter (Ra: 3.0-7.0 nm) and organic component content (spacing difference: 1.0-15.0 nm) to achieve the optimal balance between set-off prevention and contact stability. This parameter control ensures that the back coating layer maintains stable contact with drive constituents even under temperature variations.

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If environmental management conditions are alleviated to reduce cost, then power saving is achieved, but running stability deteriorates due to temperature and humidity changes

Engineering Contradiction:
Improvepower consumptionVSAvoidrunning stability
Core Design Contradiction:
Loss of energyVSStability of the object's composition

Solution Approach 1:

The magnetic tape is designed with inherent resistance to environmental changes through its specific surface roughness and organic component content parameters. The back coating layer structure provides self-regulating properties that maintain running stability without requiring strict environmental management, allowing the system to tolerate temperature and humidity variations autonomously.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention changes the material parameters of the back coating layer (surface roughness Ra: 3.0-7.0 nm, spacing difference: 1.0-15.0 nm) to create a structure that is inherently resistant to environmental changes. This allows the magnetic tape to maintain stable performance under varied environmental conditions without requiring active environmental control.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS10679657B2Magnetic tape and magnetic recording and reproducing device
Publication Date: 2020.06.09 FUJIFILM CORP

AI summary

The magnetic tape includes a non-magnetic support; a magnetic layer including a ferromagnetic powder and a binding agent on one surface of the non-magnetic support; and a back coating layer including a non-magnetic powder and a binding agent on the other surface of the non-magnetic support, in which a center line average surface roughness Ra measured regarding a surface of the back coating layer is equal to or smaller than 7.0 nm, and a difference (Safter−Sbefore) between a spacing Safter measured by optical interferometry regarding the surface of the back coating layer after ethanol cleaning and a spacing Sbefore measured by optical interferometry regarding the surface of the back coating layer before ethanol cleaning is greater than 0 nm and equal to or smaller than 15.0 nm.