Pressure Roller Adhesive Layer Electrostatic Offset

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Solution Overview

Problem

Existing fixing devices in electrophotographic printers and copiers face issues with electrostatic offset and toner stain due to the high electrical insulation properties of fluorine resin releasing layers, leading to continuous image defects and toner accumulation on the pressure roller.

Innovation Solution

A pressure roller configuration with a core metal, elastic layer, adhesive layer containing monomer electrolyte, and a releasing layer formed from fluorine resin, which includes conductive members like carbon black or ion conductive substances to improve electrostatic charge management and reduce toner adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a fluorine resin releasing layer is used on the pressure roller to prevent toner adhesion, then the releasing property is improved, but the electrostatic offset occurs due to high electrical insulation and charge accumulation

Engineering Contradiction:
Improvereleasing propertyVSAvoidelectrostatic offset
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent applies composite materials by combining fluorine resin with conductive materials (carbon black, metal particles, or ion-conductive substances) to create a releasing layer that simultaneously provides both releasing properties and electrostatic charge dissipation. This composite structure resolves the contradiction by integrating two opposing requirements into a single functional layer.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the electrical parameter of the releasing layer by incorporating conductive materials that modify its electrical resistance. The conductive material content is controlled to achieve optimal balance: enough to dissipate electrostatic charge but not so much as to compromise the releasing property. This parameter adjustment resolves the contradiction between insulation and conductivity.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If conductive materials are added to the fluorine resin releasing layer to reduce electrostatic charge, then the electrostatic offset is suppressed, but toner stain occurs due to reduced releasing property

Engineering Contradiction:
Improveelectrostatic offset suppressionVSAvoidreleasing property
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent precisely controls the concentration and distribution of conductive materials within the fluorine resin matrix to optimize the balance between electrostatic charge dissipation and toner releasing. By adjusting the amount and type of conductive additive, the patent achieves a parameter range where both electrostatic offset suppression and releasing property are maintained.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates local quality variations by distributing conductive materials non-uniformly within the releasing layer or using different conductive materials with varying properties. This allows different regions or aspects of the releasing layer to fulfill different functions: some areas provide releasing property while others provide electrostatic dissipation, resolving the contradiction between these two properties.

Inventive Principle:
Principle #3Local quality

3Object-generated harmful factors

If the electrical resistance of the pressure roller surface is decreased to prevent charge accumulation, then electrostatic offset is reduced, but toner adheres more strongly causing image defects

Engineering Contradiction:
Improvecharge accumulationVSAvoidtoner adhesion
Core Design Contradiction:
Object-generated harmful factorsVSObject-affected harmful factors

Solution Approach 1:

The patent uses composite materials combining fluorine resin base material with controlled amounts of conductive additives. This composite structure provides a balanced electrical resistance that prevents charge accumulation while maintaining sufficient releasing property to prevent excessive toner adhesion, resolving the contradiction between these two harmful effects.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the electrical resistance parameter of the pressure roller surface by controlling the type, amount, and distribution of conductive materials in the composite releasing layer. This parameter optimization achieves a sweet spot where electrical resistance is low enough to prevent charge accumulation but high enough to maintain releasing property, resolving the contradiction.

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 electrostatic offset and toner stain on the pressure roller, ensuring stable image formation without significant defects, by balancing electrostatic conductivity and releasing properties.

Implementation Method 1

the adhesive layer contains monomer electrolyte... which includes conductive members like carbon black or ion conductive substances to improve electrostatic charge management

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the fluorine resin has properties in which it is easily electrically charged and static electricity is hardly escaped therefrom... to prevent the fluorine resin of the releasing layer from being electrically charged

Methodology Applied
Scientific EffectElectrostatic discharge: Electrostatic Discharge

Implementation Method 3

a pressure roller brought into contact with the fixing roller to form a nip portion... while the recording material is pinched and transported at the nip portion

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2482140B1Pressure roller and fixing device equipped with the same
Publication Date: 2016.11.16 CANON KK
  • EP2482140B1 patent drawingFigure 1
  • EP2482140B1 patent drawingFigure 2
  • EP2482140B1 patent drawing

AI summary

A pressure roller for use in a fixing device includes a core metal, an elastic layer, a releasing layer, and an adhesive layer configured to cause the elastic layer and the releasing layer to adhere to each other, wherein the adhesive layer contains monomer electrolyte.