Imide Compound Undercoat Layer for Ghost Suppression

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Solution Overview

Problem

Existing electrophotographic photosensitive members are prone to positive ghosting due to residual charge accumulation, which is not adequately addressed by current technologies that incorporate electron-transporting substances in the undercoat layer.

Innovation Solution

Incorporating a polymerized product of an imide compound with specific hydrogen-bonding polymerizable functional groups and a bulky structure in the undercoat layer to reduce electron trap formation and agglomeration of electron-transporting molecules, thereby suppressing positive ghosting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensitivity of the charge-generating substance is increased to improve image quality, then the charge generation capability is enhanced, but residual charge accumulates in the photosensitive layer causing positive ghosting

Engineering Contradiction:
Improveimage qualityVSAvoidpositive ghosting
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

An electron-transporting substance is introduced as an intermediary component in the undercoat layer. This substance mediates the transport of electrons from the support to the photosensitive layer, preventing charge accumulation that causes positive ghosting while maintaining the benefits of high-sensitivity charge-generating substances.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The undercoat layer is cured before the photosensitive layer is applied to prevent elution of the electron-transporting substance. This preliminary curing action ensures the electron-transporting substance remains fixed and functional, preventing positive ghosting from the outset rather than addressing it after image formation.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If an electron-transporting substance is incorporated into the undercoat layer to suppress positive ghosting, then charge transport is improved, but the substance may be eluted by solvents in the photosensitive layer application liquid

Engineering Contradiction:
Improvepositive ghost suppressionVSAvoidsubstance elution resistance
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The undercoat layer containing the electron-transporting substance is cured before the photosensitive layer is applied. This preliminary curing action locks the electron-transporting substance in place, preventing its elution by solvents in subsequent application liquids while maintaining its charge transport functionality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The undercoat layer undergoes a phase transition from uncured to cured state through curing treatment. This phase change transforms the electron-transporting substance from a soluble state to an insoluble crosslinked network, preventing elution while preserving electrical properties.

Inventive Principle:
Principle #36Phase transitions

3Stability of the object's composition

If the undercoat layer is cured to prevent electron-transporting substance elution, then substance stability is improved, but positive ghosting may still occur due to insufficient electron transport

Engineering Contradiction:
Improvesubstance stabilityVSAvoidpositive ghost suppression
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The chemical structure of the electron-transporting substance is optimized by selecting compounds with specific properties (electron affinity, molecular weight, functional groups) that enable effective electron transport even in the cured state. This parameter optimization ensures sufficient electron transport capability while maintaining substance stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The undercoat layer is formulated as a composite material containing the electron-transporting substance combined with resins and crosslinking agents. This composite structure provides both the electron transport functionality and the structural stability needed to prevent elution while maintaining charge transport after curing.

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 proposed solution effectively reduces positive ghosting by maintaining the electron-transporting properties while preventing residual charge accumulation, enhancing the quality of electrophotographic images.

Implementation Method 1

the undercoat layer comprises a polymerized product of a composition including a compound represented by the following formula (1)

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP2889688B1Electrophotographic photosensitive member, process cartridge, electrophotographic apparatus, and imide compound
Publication Date: 2017.09.13 CANON KK
  • EP2889688B1 patent drawingFigure 1~3
  • EP2889688B1 patent drawingFigure 2
  • EP2889688B1 patent drawingFigure 4A~4B

AI summary

Provided is an electrophotographic photosensitive member including an undercoat layer that contains a polymerized product of a composition containing a compound represented by the formula (1).