Gallium Oxide Surface Layer for Photoreceptor Wear Resistance

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Solution Overview

Problem

Electrophotographic photoreceptors in image forming apparatuses face issues with surface deterioration due to discharge products and mechanical stress, leading to image blurring and uneven wear, which existing abrasive cleaning methods cannot effectively address without compromising the photoreceptor's surface integrity.

Innovation Solution

An electrophotographic photoreceptor with a surface layer containing gallium (Ga) and oxygen (O) as constituent elements, having a thickness of 0.2 μm to 1.5 μm and microhardness of 2 GPa to 15 GPa, which prevents uneven wear and mechanical damage, maintaining initial surface characteristics and image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If abrasive particles are mixed with developer to remove discharge products, then discharge products are rubbed off the photoreceptor, but the surface of the photoreceptor is deteriorated by abrasion

Engineering Contradiction:

Improvedischarge products adhesionVSAvoidsurface integrity

Core Design Contradiction:

Object-generated harmful factorsVSStrength

Solution Approach 1:

The patent replaces the mechanical abrasive cleaning system with an electrostatic cleaning system. Instead of using abrasive particles that physically wear the surface, the invention uses a corona discharge or ion blower to generate ions that electrostatically attract and remove discharge products from the photoreceptor surface, thereby eliminating mechanical abrasion while maintaining cleaning effectiveness

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the cleaning mechanism from mechanical abrasion to electrostatic interaction. By controlling the electrostatic potential and ion concentration parameters, the system achieves effective removal of discharge products without the harmful mechanical wear associated with abrasive particles

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the photoreceptor is exposed to various contact and stress within the apparatuses, then charging and development functions are performed, but the photoreceptor deteriorates resulting in image blurring

Engineering Contradiction:

Improveimage forming capabilityVSAvoidimage quality stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies a protective surface layer on the photoreceptor before it is exposed to harsh operating conditions. This surface layer acts as a cushioning barrier that protects the underlying photosensitive material from deterioration caused by contact with developer, toner, and environmental factors, thereby maintaining image quality stability over extended periods

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent uses composite material structures combining the photosensitive layer with a protective surface layer having different properties. The surface layer is specifically designed to be resistant to abrasion, chemicals, and environmental degradation while allowing the photosensitive layer to maintain its charging and development functions

Inventive Principle:

Principle #40Composite materials

3Strength

If the surface layer is made harder to prevent wear, then mechanical durability is improved, but the surface becomes more prone to cracking and loss of electrical properties

Engineering Contradiction:

Improvewear resistanceVSAvoidelectrical conductivity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent optimizes the surface layer's microhardness parameter within a specific range (2 GPa to 15 GPa) to achieve the right balance. This parameter optimization ensures sufficient wear resistance while preventing excessive hardness that would lead to cracking and electrical property degradation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material design where the surface layer combines hardness-providing components with flexibility-providing components. This composite structure allows the surface to resist wear while maintaining enough elasticity to prevent cracking and preserve electrical conductivity pathways

Inventive Principle:

Principle #40Composite materials

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 specified surface layer composition and properties enhance the photoreceptor's durability and electrical conductivity, preventing image defects and maintaining halftone density stability even under repeated use and varying environmental conditions.

Implementation Method 1

a microhardness of 2 GPa to 15 GPa

Methodology Applied

Scientific EffectHardness:

Implementation Method 2

discharge products adhere to the photoreceptor

Methodology Applied

Scientific EffectElectrostatic discharge: Electrostatic Discharge

Data Source

PatentUS8158316B2Electrophotographic photoreceptor, process cartridge and image forming apparatus

Publication Date: 2012.04.17 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An electrophotographic photoreceptor includes an electrically conductive substrate, an organic photosensitive layer and a surface layer laminated in this order. The surface layer includes at least gallium (Ga) and oxygen (O) as constituent elements thereof, and has a thickness of 0.2 μm to 1.5 μm, and a microhardness of 2 GPa to 15 GPa.