Electrophotographic Photosensitive Member Ionization Potential Alignment
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Solution Overview
Problem
Electrophotographic photosensitive members described in existing patents have high residual potential and potential fluctuation due to low hole injection from the support into the undercoat layer, leading to inefficient electron removal.
Innovation Solution
An electrophotographic photosensitive member configuration with an electroconductive layer having an ionization potential of 5.4 to 5.8 eV and an undercoat layer with an ionization potential of 6.0 eV or more, containing electron transporting compounds, where the ionization potential difference between the undercoat and electroconductive layers promotes hole injection and electron removal, reducing residual potential and fluctuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the undercoat layer uses conventional materials with lower ionization potential, then hole injection from support is easier, but residual potential and potential fluctuation increase due to inefficient electron removal
Solution Approach 1:
The patent changes the ionization potential parameter of the undercoat layer material to 6.0 eV or more, which is higher than conventional materials. This parameter change creates a larger energy barrier that prevents electron injection from the support, thereby reducing residual potential and potential fluctuation while maintaining reliable hole injection through the optimized energy level alignment.
Solution Approach 2:
The patent uses composite materials in the undercoat layer, specifically combining electron transporting compounds with compounds having specific ionization potentials (6.0 eV or more). This composite approach allows the layer to simultaneously achieve good hole injection properties and reduced residual potential by leveraging the complementary characteristics of different materials.
2Reliability
If the electroconductive layer has lower ionization potential, then electron removal is easier, but residual potential increases due to insufficient hole injection into the undercoat layer
Solution Approach 1:
The patent optimizes the ionization potential parameter of the electroconductive layer to 5.4-5.8 eV, creating an energy level gradient that facilitates hole injection from the support into the undercoat layer. This parameter optimization ensures efficient charge transfer while maintaining low residual potential and minimal potential fluctuation.
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 configuration effectively lowers residual potential and suppresses potential fluctuation by enhancing hole injection and electron removal in the undercoat layer, improving image quality and stability in electrophotographic apparatuses.
Implementation Method 1
the injection of holes from the support into the undercoat layer
Implementation Method 2
the undercoat layer comprises an electron transporting compound
Data Source
AI summary
An electrophotographic photosensitive member comprising a support, an electroconductive layer, an undercoat layer, a charge generating layer, and a hole transporting layer in this order, wherein when an ionization potential of the electroconductive layer is defined as IPc, the IPc is 5.4 to 5.8 eV, and when an ionization potential of the undercoat layer is defined as IPu, the IPu is 6.0 eV or more, wherein the undercoat layer comprises an electron transporting compound and a compound (α), and when an ionization potential of the compound (α) is defined as IPα, the IPc, the IPu, and the IPα satisfy relation (1):IPu−IPc>IPα−IPc (1).