Electrophotographic Photosensitive Member Intermediate Layer Design
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Solution Overview
Problem
Electrophotographic photosensitive members with intermediate layers containing metal oxide particles and electron transport substances face challenges in suppressing voltage fluctuations and black spot occurrence, especially under high-temperature and high-humidity environments.
Innovation Solution
A laminated electrophotographic photosensitive member with a first intermediate layer of metal oxide particles having a specific primary particle diameter range and a second intermediate layer comprising a polymerized product of an electron transport substance with polymerizable functional groups and a crosslinking agent, which improves film uniformity and reduces oxidation of metal oxide particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an intermediate layer containing metal oxide particles with small particle diameters is used to suppress charge injection, then charge injection suppression is improved, but voltage fluctuation suppression deteriorates under high-temperature and high-humidity environments
Solution Approach 1:
The intermediate layer is divided into two distinct layers: a first intermediate layer containing metal oxide particles for charge injection suppression, and a second intermediate layer containing an electron transport substance for voltage fluctuation suppression. This segmentation allows each layer to specialize in one function, resolving the contradiction between charge injection suppression and voltage fluctuation suppression.
Solution Approach 2:
The patent uses a composite structure combining inorganic metal oxide particles in the first intermediate layer with an organic electron transport substance in the second intermediate layer. This composite approach leverages the strengths of both material types: metal oxides for charge injection control and electron transport substances for voltage stability, particularly under high-temperature and high-humidity conditions.
2Measurement precision
If a high-sensitivity charge generation substance is used to increase charge generation, then sensitivity is improved, but charge remaining in the intermediate layer increases
Solution Approach 1:
The patent extracts the electron transport function from the intermediate layer containing metal oxide particles and places it in a separate second intermediate layer. This allows the first intermediate layer to focus on charge injection suppression while the second intermediate layer handles electron transport, preventing charge accumulation in the metal oxide layer and enabling the use of high-sensitivity charge generation substances.
3Productivity
If repeated image formation is performed for a long time period, then productivity is improved, but voltage fluctuation increases
Solution Approach 1:
The second intermediate layer containing the electron transport substance maintains continuous and stable electron transport throughout repeated image formation cycles. This continuous action prevents voltage fluctuation buildup over time, enabling long-term repeated image formation without degradation, thus resolving the contradiction between productivity and voltage stability.
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 suppresses voltage fluctuations and black spot formation in repeated image formation under high-temperature and high-humidity conditions by enhancing the reducing action and film uniformity of the intermediate layers.
Implementation Method 1
a second intermediate layer on the first intermediate layer; and a photosensitive layer on the second intermediate layer, in which: the first intermediate layer includes metal oxide particles having a number-average primary particle diameter of 30 nm or more and 450 nm or less; and the second intermediate layer includes a polymerized product of a composition including an electron transport substance having a polymerizable functional group
Data Source
AI summary
Provided is an electrophotographic photosensitive member capable of suppressing a voltage fluctuation and occurrence of a black spot under a high-temperature/high-humidity environment. The electrophotographic photosensitive member includes: a support; a first intermediate layer formed on the support; a second intermediate layer formed on the first intermediate layer; and a photosensitive layer formed on the second intermediate layer, in which the first intermediate layer contains metal oxide particles having a number-average primary particle diameter of from 30 to 450 nm; and the second intermediate layer contains a cured product of a composition containing an electron transport substance having a polymerizable functional group represented by the formula (1) or (2), and having a molecular weight of from 100 to 1,000, and a crosslinking agent having 3 to 6 groups reactive with the polymerizable functional group represented by the formula (1) or (2), and having a molecular weight of from 200 to 1,300.