Photosensitive Member Layer Composition for Ghosting-Free Printing

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Solution Overview

Problem

Existing electrophotographic photosensitive members suffer from image failures such as pattern memory and ghosting during mass and high-speed printing due to insufficient electron-conveying ability and non-uniform film states caused by perylene imide stacking.

Innovation Solution

Incorporating a polymer with a specific structural unit and a glass transition temperature of -10 to 50°C in the electron-transporting layer to suppress perylene imide stacking, enhancing electron mobility and reducing trap sites, thereby alleviating pattern memory and ghosting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional photosensitive member with higher glass transition temperature is used, then mechanical strength and durability are improved, but image quality and toner transfer characteristics deteriorate

Engineering Contradiction:
Improvemechanical strengthVSAvoidimage quality
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by precisely controlling the glass transition temperature (Tg) of the polymer in the electron-transporting layer to fall within -10°C to 50°C. This specific parameter range allows the material to exhibit optimal balance between mechanical durability and image quality, resolving the contradiction between strength and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining the polymer with specific glass transition temperature characteristics with other functional components in the photosensitive member structure. This composite approach enables simultaneous achievement of mechanical strength and optimal image quality through synergistic material properties.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If the polymer has lower glass transition temperature to improve image quality, then toner transfer characteristics improve, but mechanical durability and resistance to deformation worsen

Engineering Contradiction:
Improvetoner transfer characteristicsVSAvoidmechanical durability
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent resolves this contradiction by changing the parameter of glass transition temperature to a specific range (-10°C to 50°C) that simultaneously provides good toner transfer characteristics and sufficient mechanical durability, avoiding the extremes that cause either poor image quality or poor mechanical properties.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the electron-transporting layer has higher glass transition temperature to improve dimensional stability, then resistance to deformation improves, but charge generation and transport performance worsen

Engineering Contradiction:
Improvedimensional stabilityVSAvoidcharge generation and transport performance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies parameter changes by setting the glass transition temperature within -10°C to 50°C, which provides sufficient dimensional stability while maintaining adequate charge generation and transport performance. This parameter optimization resolves the contradiction between stability and reliability.

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 both pattern memory and ghosting by maintaining a uniform film state and improving electron mobility, even at high perylene imide concentrations.

Implementation Method 1

an electrophotographic photosensitive member which comprises in this order: a support; an electron-transporting layer; a charge-generating layer; and a hole-transporting layer

Methodology Applied
Scientific EffectPhotoconduction: Photoconductivity

Data Source

PatentEP4462190B1Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus
Publication Date: 2026.05.06 CANON KK
  • EP4462190B1 patent drawingFigure 1A~1E
  • EP4462190B1 patent drawingFigure 2A~2B
  • EP4462190B1 patent drawingFigure 3

AI summary

Provided is an electrophotographic photosensitive member including in this order: a support; an electron-transporting layer; a charge-generating layer; and a hole-transporting layer, wherein the electron-transporting layer comprises a polymer having a specific structural unit, and wherein the polymer has a glass transition temperature Tg of -10 to 50°C.