Single-Layer Electrophotographic Photoreceptor Fluorenone Derivatives

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing electrophotographic photoreceptors with single-layer photosensitive layers containing only fluorenone derivatives as electron transport materials are prone to morphological changes due to thermal diffusion, leading to cracks and electrical characteristic degradation, while using dimers of fluorenone derivatives as sole electron transport materials results in low solubility and film formation issues.

Innovation Solution

A single-layer electrophotographic photoreceptor incorporating both a monomeric fluorenone derivative as the first electron transport material and a dimerized fluorenone derivative as the second electron transport material, which synergistically prevents agglomeration and diffusion, enhances thermal stability, and maintains solubility for long-term film integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If only fluorenone derivatives are used as electron transport materials, then the photosensitive layer can be formed, but morphological changes occur due to thermal diffusion causing cracks and electrical characteristic degradation

Engineering Contradiction:

Improvecharging durabilityVSAvoidmorphological stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses a composite electron transport system combining fluorenone derivatives (first electron transport material) with other electron transport materials (second electron transport material) in a single-layer photosensitive layer. This composite approach prevents thermal diffusion-induced morphological changes while maintaining charging durability, resolving the contradiction between reliability and compositional stability.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If dimers of fluorenone derivatives are used as sole electron transport materials, then thermal stability is improved, but solubility decreases and film formation becomes difficult

Engineering Contradiction:

Improvethermal stabilityVSAvoidfilm formation

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent combines fluorenone derivatives with other electron transport materials to create a composite system that achieves thermal stability without the solubility problems of dimerized fluorenone derivatives. This allows proper film formation while maintaining compositional stability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent assigns different functional roles to different materials in the composite system: fluorenone derivatives provide electron transport capability while the second electron transport material contributes to thermal stability and solubility enhancement, allowing each component to optimize its local function.

Inventive Principle:

Principle #3Local quality

3Device complexity

If a single-layer photosensitive layer is used, then device complexity is reduced, but morphological changes and image quality defects occur

Engineering Contradiction:

Improvelayer structureVSAvoidimage quality

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent achieves high image quality and manufacturing precision within a single-layer structure by using composite electron transport materials. The combination of fluorenone derivatives and second electron transport materials prevents morphological changes and image defects without requiring multiple layers, thus maintaining low device complexity.

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 combined use of monomeric and dimeric fluorenone derivatives in the photosensitive layer prevents morphological changes, improves charging durability, and reduces defects in image quality, such as black spots, while maintaining film stability and solubility over time.

Implementation Method 1

a photosensitive layer that is a single layer type photosensitive layer provided on the conductive substrate

Methodology Applied

Scientific EffectPhotoconductivity: Photoconductivity

Implementation Method 2

a first electron transport material represented by the formula (1), and a second electron transport material represented by the formula (2)

Methodology Applied

Scientific EffectElectron transport: Conduction (electrical)

Data Source

PatentUS9563138B2Electrophotographic photoreceptor, process cartridge, and image forming apparatus

Publication Date: 2017.02.07 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An electrophotographic photoreceptor includes a single layer type photosensitive layer which includes a binder resin, a charge generating material, a hole transport material, a first electron transport material represented by the formula (1), and a second electron transport material represented by the formula (2),wherein X1 represents an oxygen atom or ═C(CN)2; R11 to R17 independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, or an aralkyl group; and R18 represents an alkyl group, -L111-O—R112, an aryl group, or an aralkyl group; provided that L111 represents an alkylene group, and R112 represents an alkyl group,wherein X2 represents an oxygen atom or ═C(CN)2; R21 to R27 independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group or an aralkyl group; and R28 represents an alkylene group having 4 to 20 carbon atoms or the like.