Fixing Roller Grounding Structure to Suppress Abrasion and Noise

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Solution Overview

Problem

Existing fixing devices in image forming apparatuses face issues with abrasion and abnormal noise due to direct contact between the ground member and the rotating pressure roller, which can lead to improper grounding and potential damage to electrical components.

Innovation Solution

A grounding structure is implemented using a rolling bearing member and a ground member that electrically grounds the pressure roller via an insulated bearing holder, with compression coil springs and a resistance member to prevent abrasion and noise, ensuring stable grounding and preventing overcurrent transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the ground member directly contacts the rotating pressure roller, then grounding is achieved, but abrasion and abnormal noise occur leading to improper grounding

Engineering Contradiction:
Improvegrounding stabilityVSAvoidabrasion and noise
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A plate spring member is introduced as an intermediary between the ground member and the pressure roller. The plate spring member abuts on the outer peripheral surface of the pressure roller, allowing the ground member to contact the plate spring member instead. This intermediary prevents direct contact between the ground member and pressure roller, eliminating abrasion and noise while maintaining effective grounding through the conductive plate spring member.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple ring-shaped members are arranged on the pressure roller, then surface damage is prevented, but device complexity increases

Engineering Contradiction:
Improveroller surface protectionVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The grounding function and the roller surface protection function are merged into a single plate spring member. The plate spring member simultaneously serves as the grounding contact element and the protective element that abuts on the pressure roller outer peripheral surface, eliminating the need for separate ring-shaped members and reducing device complexity while maintaining both functions.

Inventive Principle:
Principle #5Merging (Combining)

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 abrasion and noise at the grounding contact point, maintains proper grounding of the pressure roller, and prevents damage to electrical circuits by managing overcurrent, enhancing the reliability of the image forming apparatus.

Implementation Method 1

The rolling bearing member is disposed between either of the fixing member and the pressure member and the fixing frame in an electrically insulated state. The ground member electrically grounds either of the fixing member and the pressure member via the rolling bearing member.

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

compression coil springs and a resistance member to prevent abrasion and noise

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4679189A1Fixing device and image forming apparatus
Publication Date: 2026.01.14 KYOCERA DOCUMENT SOLUTIONS INC
  • EP4679189A1 patent drawingFigure 1
  • EP4679189A1 patent drawingFigure 2
  • EP4679189A1 patent drawingFigure 3

AI summary

A fixing device (7) includes a fixing member (20), a pressure member (21), a fixing frame (23), a rolling bearing member (30), and a ground member (60). The fixing member (20) heats a toner on a medium. The pressure member (21) forms a pressure region with the fixing member (20) and pressurizes the toner on the medium passing through the pressure region. The fixing frame (23) supports both ends of the fixing member (20) and the pressure member (21). The rolling bearing member (30) is disposed between either of the fixing member (20) and the pressure member (21) and the fixing frame (23) in an electrically insulated state. The ground member (60) electrically grounds either of the fixing member (20) and the pressure member (21) via the rolling bearing member (30).