Fixing Film Electroconductive Layer Abrasion Reduction

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Solution Overview

Problem

The existing fixing devices in electrophotographic copying machines and printers face heat generation non-uniformity issues due to abrasion between the sliding member and the heat generating layer, leading to inconsistent toner image fixation.

Innovation Solution

A fixing device with a cylindrical film having a heat generating layer and an electroconductive layer, where the sliding member has higher thermal conductivity than the supporting member, and its longitudinal end is positioned between the inner and outer end surfaces of the electroconductive layer, reducing heat generation non-uniformity by minimizing abrasion and maintaining stable heat generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the sliding member slides on the heat generating layer, then the fixing device can form a nip and feed recording material, but the heat generating layer is abraded and heat generation non-uniformity occurs

Engineering Contradiction:

Improvenip formation and recording material feedingVSAvoidheat generation uniformity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent introduces an electroconductive layer as an intermediary between the sliding member and the heat generating layer. This intermediate layer receives the sliding contact from the sliding member, preventing direct abrasion of the heat generating layer while still allowing the nip to form and recording material to be fed through the system.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The electroconductive layer is positioned specifically at the longitudinal end portion of the film where the sliding member contacts the film. This localized structure provides abrasion resistance only where needed (at the contact region) while leaving the rest of the heat generating layer intact for uniform heat generation.

Inventive Principle:

Principle #3Local quality

2Device complexity

If the sliding member contacts the heat generating layer at the longitudinal end, then the structure is simple, but abrasion occurs and heat generation becomes non-uniform

Engineering Contradiction:

Improvefilm structureVSAvoidheat generation uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Stability of the object's composition

If the sliding member is supported from the opposite side, then the sliding member is stabilized, but thermal conductivity is insufficient to prevent heat generation non-uniformity

Engineering Contradiction:

Improvesliding member stabilityVSAvoidheat generation uniformity

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent changes the thermal conductivity parameter of the sliding member by selecting a material with high thermal conductivity. This allows the sliding member to act as a heat transfer component, conducting heat from the heat generating layer to maintain uniform temperature distribution and prevent heat generation non-uniformity.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively suppresses heat generation non-uniformity, ensuring consistent toner image fixation across large and small-sized recording materials, even after passing a significant number of sheets, by preventing abrasion and maintaining temperature uniformity within a narrow range.

Implementation Method 1

a cylindrical film including a heat generating layer that generates heat by energization

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a thermal conductivity of the sliding member is higher than a thermal conductivity of the supporting member

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10310424B2Fixing device that alleviates a physical load on non-heat-generating regions of a heat generating layer of a fixing film

Publication Date: 2019.06.04 CANON KK

AI summary

A fixing device includes a cylindrical film including a heat generating layer and an electroconductive layer electrically connected with the heat generating layer. A volume resistivity of the electroconductive layer is less than a volume resistivity of the heat generating layer. The fixing device further includes an energizing member, a roller, a sliding member, and a supporting member. A thermal conductivity of the sliding member is greater than a thermal conductivity of the supporting member. A recording material on which a toner image is formed is heated while being fed through a nip. A longitudinal end of the sliding member is positioned between an inner end surface and an outer end surface of the electroconductive layer with respect to the longitudinal direction of the film.