Photoreceptor Undercoat Composition for Humidity-Resistant Charge Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrophotographic photoreceptors with an undercoat layer containing electron transport materials experience charge retention property deterioration when operated in high-temperature and high-humidity environments due to electrochemical corrosion.
Innovation Solution
The photoreceptor design includes a configuration where the ratio of electron transport material content is limited in the undercoat layer near the interface with the charge generation layer, suppressing infiltration of moisture and reducing electrochemical corrosion, thereby maintaining excellent charge retention properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an electron transport material is used in the undercoat layer to replace metal oxide for environmentally low-impact manufacturing, then environmental friendliness is improved, but charge retention property deteriorates in high-temperature and high-humidity environments due to electrochemical corrosion
Solution Approach 1:
The patent applies local quality by creating a gradient structure in the undercoat layer where the electron transport material concentration varies with depth. Specifically, the ratio of electron transport material content in the region within 4% from the interface (X1) to the content in the region exceeding 4% from the interface (X2) is controlled to be 0 or 78 or less. This local variation in material distribution protects the charge generation layer interface from electrochemical corrosion while maintaining the environmental benefits of using organic electron transport materials.
2Power
If the electron transport material content is increased to improve electron transport performance, then electron transport ability is improved, but electrochemical corrosion accelerates in high-temperature and high-humidity environments, worsening charge retention
Solution Approach 1:
The patent implements local quality by establishing a non-uniform distribution of electron transport material throughout the undercoat layer thickness. The controlled ratio (X1/X2 ≤ 0 or 78) creates a gradient where lower concentrations near the interface reduce corrosion risk, while sufficient concentrations deeper in the layer maintain electron transport performance. This resolves the contradiction between performance and reliability.
Solution Approach 2:
The patent transitions from considering only the total amount of electron transport material to considering its spatial distribution in the thickness direction. By introducing the depth-dependent concentration ratio (X1/X2) as a new dimensional parameter, the patent enables simultaneous optimization of both electron transport performance and corrosion resistance.
Data Source
AI summary
An electrophotographic photoreceptor includes a conductive substrate, an undercoat layer that is provided on the conductive substrate and contains an electron transport material and a binder resin, a charge generation layer that is provided on the undercoat layer, and a charge transport layer that is provided on the charge generation layer, in which, in the undercoat layer, a ratio (X1/X2) of a content X1 (% by mass) of the electron transport material in a region within 4% in a thickness direction of the undercoat layer from an interface between the undercoat layer and the charge generation layer to a content X2 (% by mass) of the electron transport material in a region exceeding 4% in the thickness direction of the undercoat layer from the interface between the undercoat layer and the charge generation layer is 0 or 78 or less.