Photoconductive Layer Crack Suppression via Amine Structure

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Solution Overview

Problem

Electrophotographic photoconductive members with organic photoconductive layers face issues of crack generation and black spots due to the high crystallinity of amine compounds used as hole transferring materials, which leads to poor adhesion and sensitivity, especially when exposed to oil components.

Innovation Solution

Incorporating a binder resin with an IV/OV value of 0.36 or more and using amine compounds represented by specific general formulas to improve dispersibility and reduce crystallinity, thereby enhancing the stability and compatibility of the photoconductive layer, which suppresses crack generation and black spots in the formed image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an amine compound with high charge transfer rate is used as a hole transferring material, then electrical characteristics are improved, but the photoconductive layer easily separates from the substrate and cracks are easily generated

Engineering Contradiction:

Improveelectrical characteristicsVSAvoidadhesion strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent changes the chemical structure parameters of the amine compound by introducing specific substituents (X1 and X2) at defined positions in the molecular structure. This structural modification reduces crystallinity while maintaining charge transfer capability, thereby improving adhesion strength without sacrificing electrical characteristics

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite photoconductive layer by combining the modified amine compound (formula 1) with specific binder resins and charge generating materials. This composite structure balances the high charge transfer rate requirement with improved adhesion and crack resistance through synergistic material interactions

Inventive Principle:

Principle #40Composite materials

2Reliability

If an amine compound is used as a hole transferring material, then charge transfer rate is improved, but cracks are easily generated when oil components adhere onto the surface

Engineering Contradiction:

Improvecharge transfer rateVSAvoidcrack generation from oil adhesion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the amine compound structure by adding substituents X1 and X2, which change the surface properties and intermolecular interactions. This reduces the compound's sensitivity to oil components while preserving its charge transfer function, preventing crack generation upon oil adhesion

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent transforms the previously harmful high crystallinity of amine compounds into a benefit by controlled structural modification. The modified structure maintains ordered arrangements for efficient charge transfer while introducing enough disorder to prevent oil-induced crack propagation

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If conventional amine compounds are used to achieve high charge transfer rate, then electrical performance is improved, but black spots are generated in the formed image due to crack formation

Engineering Contradiction:

Improveelectrical performanceVSAvoidimage quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

By changing the molecular structure parameters of the amine compound (formula 1) through specific substituent placement, the patent achieves a balance where charge transfer efficiency is maintained but crack formation is suppressed, thereby eliminating black spots in the final image

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite formulation combining the modified amine compound with specific binder resins and charge generating materials, creating a photoconductive layer that simultaneously achieves high electrical performance and image quality without black spot defects

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 solution effectively maintains high electrical characteristics while significantly reducing crack formation and black spots, ensuring improved performance and longevity of image forming apparatuses.

Implementation Method 1

the binder resin has a IV/OV value in which an inorganic value (IV) is divided by an organic value (OV) of 0.36 or more... improve dispersibility and reduce crystallinity

Methodology Applied

Scientific EffectDispersibility: Dispersion (of waves)

Implementation Method 2

a photoconductive layer containing a hole transferring material, a charge generating material and a binder resin

Methodology Applied

Scientific EffectPhotoconductivity: Photoconductivity

Implementation Method 3

the hole transferring material contains an amine compound... It is required for the charge transferring material to have a high charge transfer rate

Methodology Applied

Scientific EffectCharge transfer: Conduction (electrical)

Data Source

PatentUS7754402B2Electrophotographic photoconductive member and image forming apparatus

Publication Date: 2010.07.13 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

The present invention provides an electrophotographic photoconductive member comprising a substrate, and a photoconductive layer containing a hole transferring material, a charge generating material and a binder resin, wherein a value (IV/OV value) in which the inorganic value is divided by the organic value of the binder resin is 0.36 or more and the hole transferring material contains an amine compound represented by the following general formula (1):