Polyester Resin Photoreceptor Adhesion and Abrasion

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Solution Overview

Problem

Electrophotographic photoreceptors using polyester resins suffer from insufficient mechanical strength, abrasion resistance, and adhesion to the support, particularly in high-speed and long-life models, due to poor reactivity of aliphatic divalent alcohols in interfacial polymerization and inadequate introduction of divalent phenol and carboxylic acid residues.

Innovation Solution

Incorporating a specific partial structure with divalent phenol and carboxylic acid residues in the polyester resin, such as those represented by certain formulas, to enhance the photoreceptor's mechanical properties and adhesion, achieved through a combination of interfacial and solution polymerization methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If interfacial polymerization method is used to produce polyester resin, then high molecular weight and high purity are obtained, but aliphatic divalent alcohol cannot be introduced due to poor reactivity

Engineering Contradiction:

Improvepurity of polyester resinVSAvoidability to introduce aliphatic divalent alcohol

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the reaction parameters by using solution polymerization instead of interfacial polymerization, allowing aliphatic divalent alcohols to be incorporated into the polyester resin while maintaining acceptable purity and molecular weight

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses an intermediary approach by combining solution and interfacial polymerization methods, where solution polymerization introduces the aliphatic divalent alcohol and interfacial polymerization completes the high-purity polyester resin formation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If polyester resin is used as binder resin in photosensitive layer, then sensitivity and solubility are improved, but mechanical strength is insufficient

Engineering Contradiction:

Improvesensitivity of photoreceptorVSAvoidmechanical strength of photosensitive layer

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent creates a composite polyester resin system combining aromatic and aliphatic components, where the aromatic portion provides structural strength and the aliphatic portion provides flexibility and solubility, achieving both mechanical strength and sensitivity

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by having different functional groups within the polyester resin serve different purposes: aromatic rings provide mechanical strength and rigidity, while aliphatic chains provide flexibility and solubility

Inventive Principle:

Principle #3Local quality

3Strength

If polyester resin is used as binder resin, then abrasion resistance is improved, but adhesion to support and undercoat layer is insufficient

Engineering Contradiction:

Improveabrasion resistance of photosensitive layerVSAvoidadhesion force between layers

Core Design Contradiction:

StrengthVSForce

Solution Approach 1:

The patent modifies the chemical composition parameters of the polyester resin by incorporating specific functional groups that enhance both abrasion resistance and adhesion properties simultaneously

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10884348B2Electrophotographic photoreceptor, and electrophotographic cartridge and image forming apparatus including same

Publication Date: 2021.01.05 MITSUBISHI CHEM CORP

AI summary

The present invention aims to provide an electrophotographic photoreceptor which is excellent in abrasion resistance against practical load and excellent in initial electrical properties, preferably further excellent in adhesion between layers by containing a polyester resin excellent in abrasion resistance, which is an electrophotographic photoreceptor containing a photosensitive layer and a conductive support, the electrophotographic photoreceptor containing a polyester resin having a specific structure α with a number average molecular weight of 15,000 or less and containing a divalent phenol residue and a divalent carboxylic acid residue.