Undercoat Layer Adhesion in Electrophotographic Photosensitive Members
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Solution Overview
Problem
Existing electrophotographic photosensitive members face challenges with adhesiveness between the undercoat layer and the photosensitive layer due to the hardening of the undercoat layer, which leads to internal stress and insufficient flexibility, affecting durability and electron mobility.
Innovation Solution
Incorporating at least one type of particles, such as resin particles with a hollow structure or rubber particles, into the undercoat layer, along with an electron transporting material and a cross-linking agent, to enhance adhesiveness and electron mobility while maintaining durability, with specific mass ratios and Martens hardness ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the undercoat layer contains a cured product including an electron transporting material and a cross-linking agent, then electron mobility is improved, but adhesiveness between the undercoat layer and photosensitive layer deteriorates due to hardening
Solution Approach 1:
The undercoat layer uses a composite material system combining electron transporting material (for electron mobility), cross-linking agent (for durability), and resin particles (for adhesiveness). This composite structure resolves the contradiction by integrating multiple functional materials that simultaneously provide electron transport capability and bonding strength to the photosensitive layer.
Solution Approach 2:
The patent optimizes the content ratio of electron transporting material to cross-linking agent within specific ranges (electron transporting material: 30-70 mass%, cross-linking agent: 10-50 mass%). By controlling these compositional parameters, the undercoat layer achieves both sufficient electron mobility and adequate adhesiveness, resolving the contradiction through parameter optimization.
2Strength
If the undercoat layer is hardened to improve durability, then structural strength is improved, but flexibility deteriorates leading to internal stress
Solution Approach 1:
The undercoat layer exhibits local quality differentiation through the resin particle distribution. The matrix provides hardness and durability, while the dispersed resin particles provide localized flexibility and stress absorption. This local quality variation allows the material to simultaneously achieve durability and flexibility.
Solution Approach 2:
The resin particles act as flexible micro-domains within the hardened undercoat layer matrix. These particle inclusions provide localized flexibility that prevents crack propagation and reduces internal stress, allowing the overall structure to maintain both hardness and flexibility.
3Reliability
If the content of electron transporting material is increased to improve electron mobility, then electron transport capability is improved, but the undercoat layer becomes too hard and loses flexibility
Solution Approach 1:
The patent specifies optimal content ranges for electron transporting material (30-70 mass%) and cross-linking agent (10-50 mass%) to balance electron mobility and flexibility. By controlling these parameters within defined ranges, the undercoat layer achieves sufficient electron transport capability while maintaining adequate flexibility through proper compositional ratios.
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 adhesiveness between the undercoat and photosensitive layers, preventing electron entry from the support member and facilitating electron movement, thereby improving image quality and reducing ghost phenomena.
Implementation Method 1
an undercoat layer, which contains a cured product including an electron transporting material... facilitating movement of electrons from the photosensitive layer side to the support member side
Implementation Method 2
a cured product obtained by polymerizing a composition including an electron transporting material, a cross-linking agent, and a resin
Data Source
AI summary
An electrophotographic photosensitive member includes a support member, an undercoat layer, and a photosensitive layer adjacent to the undercoat layer in this order, wherein the undercoat layer contains a polymerized product of a composition including an electron transporting material having a polymerizable functional group, a cross-linking agent, and a thermoplastic resin having a polymerizable functional group, and at least one type of particles selected from the group consisting of resin particles having a hollow structure and rubber particles, wherein a content of the electron transporting material in the undercoat layer is 30% by mass or more with respect to a total mass of the composition, and wherein a content of the at least one type of particles in the undercoat layer is 10% by mass or more and 100% by mass or less with respect to the content of the electron transporting material.