Developing Member Alumina Protrusions Charge Retention

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Solution Overview

Problem

Existing developing members in electrophotographic apparatuses experience a reduction in triboelectric charge imparting ability over time due to alumina drop-off and toner contamination, especially at high process speeds, leading to reduced image quality and fogging issues.

Innovation Solution

A developing member with a surface layer containing alumina particles and a resin, where the alumina particles are exposed at protrusions and the resin is interposed among them, enhancing adhesive force and minimizing contamination, thus maintaining triboelectric charge imparting ability even after long-term use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If alumina is used in the surface layer to enhance triboelectric charge imparting ability, then the ability to charge toners is improved, but alumina drops off from the surface over time reducing the charge imparting ability

Engineering Contradiction:

Improvetriboelectric charge imparting abilityVSAvoidservice life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The surface layer is constructed as a composite material containing alumina particles dispersed in a binder resin. This composite structure allows the alumina to provide triboelectric charge while the resin matrix holds the alumina particles in place, preventing drop-off and maintaining performance throughout the developing member's service life.

Inventive Principle:

Principle #40Composite materials

2Reliability

If friction between developing member and toner feeding roller increases to improve charge imparting, then triboelectric charge ability is enhanced, but contamination of the developing member surface increases

Engineering Contradiction:

Improvetriboelectric charge imparting abilityVSAvoidsurface contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The surface roughness parameter is optimized to balance charge imparting and contamination resistance. The protrusions created by alumina particle aggregation provide sufficient friction for charging while their geometry and distribution minimize the contact area that becomes contaminated, allowing the developing member to maintain performance over time.

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 retains the triboelectric charge imparting ability of the developing member, reducing fogging and ensuring high-quality image formation over a large number of prints, even at high process speeds.

Implementation Method 1

developing members deliver toners to regions to be developed, and impart triboelectric charge to the toners

Methodology Applied

Scientific EffectTriboelectric effect: Triboelectric Effect

Implementation Method 2

the resin being interposed among the alumina particles

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3239781B1Developing member, process cartridge, and electrophotographic image forming apparatus

Publication Date: 2019.04.03 CANON KK

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AI summary

The present disclosure provides developing member superior in triboelectric charge imparting ability to a toner. The developing member includes a substrate and a surface layer, the surface layer containing alumina particles and a resin, the surface layer having protrusions on the surface thereof. Each of the protrusions containing the alumina particles, part or all of the alumina particles being exposed at the surfaces of the protrusions, and the resin being interposed among the alumina particles.