Conductive Roller Surface Layer to Prevent Particle Detachment

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Solution Overview

Problem

Roller members in image forming devices experience detachment and scraping of particles from the surface layer, leading to image defects due to inadequate charging performance.

Innovation Solution

A conductive roller with a surface layer composed of a mixture of energy ray-curable urethane resin and heat-curable urethane (meth)acrylate particles, where both the surface layer and particles are made from the same urethane-based resin, enhancing adhesion and resistance to detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If particles are dispersed in the surface layer to control surface roughness and charging properties, then charging performance is improved, but particle detachment and scraping occur during use leading to image defects

Engineering Contradiction:
Improvecharging performanceVSAvoidparticle detachment
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses a composite surface layer comprising a resin matrix (urethane acrylate or polyurethane resin) with dispersed particles (TiO2, SiO2, ZrO2, or Al2O3). The resin component provides binding strength while the particles provide surface roughness control and charging properties, creating a composite structure that prevents particle detachment while maintaining desired surface properties

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies particular resin types (urethane acrylate or polyurethane) with defined molecular weight ranges (1,000-10,000) and glass transition temperatures (-50°C to 0°C). These parameter specifications ensure the resin has appropriate adhesion strength and flexibility to firmly bind particles while withstanding operational stresses, thereby preventing particle detachment

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a surface layer is added on the elastic layer to control roller surface properties, then charging properties are improved, but particle scraping occurs during contact with photoreceptor

Engineering Contradiction:
Improvecharging propertiesVSAvoidparticle scraping
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The surface layer is constructed as a composite material where the resin matrix (urethane acrylate or polyurethane) embeds inorganic particles. This composite structure allows the resin to provide a protective matrix that prevents particle scraping during contact, while the exposed particle surfaces maintain the desired charging properties and surface roughness

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The surface layer exhibits local quality differentiation where the resin component provides protective binding and anti-scraping properties in regions subject to contact stress, while the dispersed particles provide charging functionality and surface roughness control. This spatial differentiation of functions resolves the contradiction between preventing scraping and maintaining charging properties

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

The solution prevents particle detachment and scraping, ensuring stable image performance by improving wettability and cross-linking between the surface layer and particles, thus maintaining image quality during prolonged use.

Implementation Method 1

the surface layer is formed by curing, with energy ray irradiation, a mixture obtained by mixing the thus obtained particles and a surface layer resin composition comprising an energy ray-curable urethane resin

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

the particles are composed of a particle resin composition comprising a urethane (meth)acrylate, wherein the particles are heat-curable

Methodology Applied
Scientific EffectThermal polymerization:

Data Source

PatentEP3413137B1Conductive roller, and production method therefor
Publication Date: 2021.07.14 BRIDGESTONE CORP
  • EP3413137B1 patent drawingFigure 1~3A
  • EP3413137B1 patent drawingFigure 3B~3E

AI summary

Provided are: a conductive roller in which detachment and scraping of particles from a surface layer are unlikely to occur; and a method of producing the same. A conductive roller 10 includes: a shaft 1; and an elastic layer 2 and a surface layer 3, which are sequentially formed on the outer circumference of the shaft 1. In this conductive roller 10, the surface layer 3 is composed of a mixture of a surface layer resin composition and particles, the surface layer resin composition contains a heat-curable or energy ray-curable urethane resin, and the particles are composed of a particle resin composition containing a urethane (meth)acrylate.