Fixing Device Pressing Roller Static Elimination

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Solution Overview

Problem

Conventional image forming apparatuses face issues with electrical charging of the pressing roller, leading to the recording medium winding around the roller and toner attachment, due to the insulating properties of the elastic and release layers, which necessitate additional components like static elimination sheets and increased complexity.

Innovation Solution

A fixing device with a pressing force changing mechanism incorporating an electrically conductive rotation shaft and a static elimination sheet to eliminate electrical charges from the pressing member, eliminating the need for additional components and simplifying the structure by grounding the rotation shaft and integrating the static elimination function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pressing roller with elastic and release layers is used, then the fixing device can effectively fix toner images, but the pressing roller surface becomes electrically insulating and accumulates electrical charge

Engineering Contradiction:

Improvefixing performanceVSAvoidelectrical charge accumulation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent combines the pressing roller and static elimination sheet into a single integrated component. The static elimination sheet is wound around the pressing roller, merging the pressing function and static elimination function into one structure, thereby eliminating the need for separate static elimination components while maintaining both fixing performance and charge elimination capabilities

Inventive Principle:

Principle #5Merging (Combining)

2Object-generated harmful factors

If a separate static elimination sheet and plate spring are added, then electrical charge can be eliminated, but the device complexity and component count increase

Engineering Contradiction:

Improveelectrical charge accumulationVSAvoidcomponent count

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the static elimination sheet with the pressing roller structure, eliminating the need for separate plate springs and additional mounting components. This integration reduces the overall component count and simplifies the device structure while maintaining effective static elimination functionality

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The pressing roller is designed to serve multiple functions: it provides mechanical pressing force for fixing and simultaneously acts as a static elimination component through the conductive sheet wound around it. This multi-functionality reduces the need for separate dedicated static elimination components

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If the pressing roller surface is made electrically insulating, then release properties are improved, but recording medium winding around the roller occurs due to friction charge

Engineering Contradiction:

Improverelease layer propertiesVSAvoidrecording medium winding

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent integrates a conductive static elimination sheet around the insulating pressing roller, combining the benefits of both insulating materials (for release properties) and conductive materials (for charge elimination). This allows the pressing roller to maintain its release layer properties while simultaneously preventing recording medium winding through active charge neutralization

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

Effectively suppresses electrical charging of the pressing roller, preventing medium winding and toner attachment, while reducing manufacturing costs and component count by integrating the static elimination function within the existing structure.

Implementation Method 1

The rotation shaft is electrically grounded. The rotation shaft is provided with a static elimination sheet for eliminating electrical charge from the surface of the pressing member

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

The heating member heats an unfixed toner image carried on a recording medium

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20190072888A1Fixing device and image forming apparatus therewith

Publication Date: 2019.03.07 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

A fixing device has a heating member, a pressing member, a pressurizing mechanism pressing the pressing member against the heating member and a pressing force changing mechanism changing the pressing force of the pressing member against the heating member. The pressing force changing mechanism has an electrically conductive rotation shaft arranged opposite the surface of the pressing member across a predetermined interval, and a pressing force changing member provided at an end part of the rotation shaft and rotating about the rotation shaft to change the pressing force of the pressurizing mechanism. The rotation shaft has a static elimination sheet for eliminating electrical charge from the surface of the pressing member.