Electrophotographic Photosensitive Member Polyester Resin Surface Layer
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Solution Overview
Problem
Existing electrophotographic photosensitive members face challenges in achieving high responsiveness and durability while reducing ghosting and memory effects of light, as previous techniques have not adequately addressed these requirements.
Innovation Solution
An electrophotographic photosensitive member is developed with a surface layer containing a charge transporting material and a polyester resin, featuring specific structural units that enhance both durability and responsiveness, including a rigid and flexible structure with a bulky portion, which reduces ghosting and memory effects by evenly distributing charge carriers and increasing the degree of freedom of the charge transporting material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a charge transport layer is used to improve responsiveness, then charge carrier mobility increases, but the layer becomes vulnerable to external electrical and mechanical forces
Solution Approach 1:
The patent creates a composite surface layer combining a polyester resin matrix with specific charge transporting materials (triarylamine compounds). This composite structure provides both the mechanical strength and electrical properties needed, resolving the contradiction between responsiveness and durability.
Solution Approach 2:
The invention places charge transporting materials specifically within the polyester resin surface layer at controlled concentrations. This local concentration of functional materials provides high responsiveness where needed while the surrounding resin matrix provides mechanical protection, addressing the durability concern.
2Speed
If the charge transport layer acts as the surface layer to improve responsiveness, then charge carrier mobility increases, but resistance to external forces decreases
Solution Approach 1:
The surface layer is formulated as a composite material where the polyester resin provides mechanical strength and the embedded triarylamine compounds provide charge transport capability. This composite approach allows both requirements to be satisfied simultaneously.
Solution Approach 2:
The patent optimizes parameters including the concentration of charge transporting material (5-50 parts by mass per 100 parts polyester resin), molecular weight of polyester (5,000-200,000), and layer thickness (5-50 μm) to achieve the right balance between mechanical strength and charge transport performance.
3Strength
If conventional polyester resins are used in the surface layer, then mechanical strength improves, but charge carrier mobility and responsiveness deteriorate
Solution Approach 1:
The patent introduces specific triarylamine compounds with high charge carrier mobility into the polyester resin matrix. These localized functional materials provide the needed responsiveness without compromising the overall mechanical structure of the polyester resin.
Solution Approach 2:
By creating a composite of polyester resin and triarylamine charge transporting materials, the invention achieves both mechanical strength from the resin and high charge carrier mobility from the triarylamine compounds, overcoming the limitation of conventional single-material approaches.
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 achieves high durability and responsiveness, effectively reducing ghosting and memory effects of light, with optimal proportions of structural units in the polyester resin enhancing charge carrier mobility and image quality.
Implementation Method 1
Japanese Patent Laid-Open No. 2008-74714 discloses a technique using a charge transporting material having a high charge carrier mobility in the charge transport layer for increasing the responsiveness of an electrophotographic photosensitive member.
Data Source
AI summary
An electrophotographic photosensitive member includes a surface layer containing a charge transporting material and a polyester resin having a specific structure.