Fixing Apparatus Temperature Sensor Friction Reduction

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Solution Overview

Problem

In image forming apparatuses using the electro-photographic method, contact type temperature sensors often malfunction due to deformation of the flexible surface layer on the heating member, causing defects like abnormal sounds, wire breakage, and increased driving torque, when used in conjunction with a heating member having a flexible surface layer for uniform toner fixing.

Innovation Solution

A fixing apparatus with a heating member having an elastically deformable surface layer, where the paper sheet passing area has a lower surface roughness (Ra < 0.1 μm) and the non-passing area has a higher surface roughness (Ra ≥ 0.1 μm), allowing the temperature sensor to contact the non-passing area, reducing frictional resistance and preventing sensor malfunctions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a contact type temperature sensor is used to reduce cost, then the apparatus cost is reduced, but the temperature sensor interlocks with the flexible surface layer causing abnormal sounds, wire breakage, and increased driving torque

Engineering Contradiction:

Improveapparatus costVSAvoidtemperature sensor operation

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The surface layer is configured with different surface roughness in different regions: a first region with lower surface roughness (Ra < 0.1 μm) where the temperature sensor contacts, and a second region with higher surface roughness (Ra ≥ 0.1 μm) for paper sheet passage. This local differentiation allows the temperature sensor to contact a smoother area, reducing friction and preventing interlocking with the flexible surface layer, while the higher roughness region maintains adequate toner fixing performance.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If a flexible surface layer is formed on the heating member to uniformly heat toner images, then fixing quality is improved, but the surface layer deforms causing temperature sensor malfunctions

Engineering Contradiction:

Improvefixing uniformityVSAvoidtemperature sensor operation

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The surface layer has spatially differentiated surface roughness: the first region (Ra < 0.1 μm) provides a stable contact surface for the temperature sensor, reducing deformation-induced interlocking, while the second region (Ra ≥ 0.1 μm) maintains the flexibility needed for uniform toner fixing across the image area.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The surface layer acts as an intermediary element with differentiated properties: in the first region it provides a stable, low-friction contact surface for the temperature sensor, while in the second region it maintains flexibility for uniform heat distribution to the toner image, thus mediating between sensor reliability and fixing quality.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If the temperature sensor contacts the flexible surface layer, then temperature detection is achieved, but frictional resistance increases causing abnormal sounds and wire breakage

Engineering Contradiction:

Improvetemperature detectionVSAvoidfrictional resistance

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The surface layer is configured with a first region having lower surface roughness (Ra < 0.1 μm) specifically where the temperature sensor contacts, reducing frictional resistance and preventing harmful effects like abnormal sounds and wire breakage, while maintaining temperature detection capability.

Inventive Principle:

Principle #3Local quality

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

This configuration enables smooth operation of the temperature sensor, preventing defects like abnormal sounds and wire breakage, while maintaining high-quality image formation by ensuring uniform heat application and reducing driving torque, thus ensuring long-term apparatus functionality.

Implementation Method 1

a heating member which is provided with a surface layer

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

a pressing member which press-contacts the heating member

Methodology Applied

Scientific EffectMechanical pressure: Compression

Data Source

PatentUS7546079B2Fixing apparatus and image forming apparatus including a contact type temperature sensor placed stably on a paper non-passing zone of a fixing member

Publication Date: 2009.06.09 KONICA MINOLTA BUSINESS TECH INC

AI summary

There is described a fixing apparatus for fixing a toner image onto a recording material, which makes it possible not only to reduce the frictional resistance generated between a temperature sensor and a heating member, but also to prevent occurrences of abnormal sounds and breaking of the wire coupled to the temperature sensor, both caused by the direct contact between them. The fixing apparatus includes: a heating member provided with a surface layer, which is elastically deformable and includes the paper sheet passing area and the paper sheet non-passing area; a pressing member that press-contacts the heating member; and a temperature sensor that contacts the paper sheet non-passing area of the surface layer. A surface roughness Ra of the paper sheet non-passing area is set at such a value that is larger than that of a paper sheet passing area.