Electrophotographic Photosensitive Member Coating Method
Solution Overview
Problem
Existing methods for preparing electrophotographic photosensitive members with surface depressed portions are limited by low productivity, difficulty in achieving uniformity and fine processing, and challenges in fabricating complex surface shapes, which affect mechanical strength and chemical stability.
Innovation Solution
A method using a coating liquid with a hydrophilic solvent and a hydrophobic solvent, where the hydrophilic solvent has a boiling point equal to or higher than the hydrophobic solvent and a dipole moment of 0 to 2.8, and the hydrophobic solvent constitutes 50-100% of the solvent mixture, promoting condensation to form depressed portions on the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If surface processing is performed by independent steps (abrading or sand blasting), then depressed portions can be formed on the surface, but productivity decreases and uniformity and fine processing capability are insufficient
Solution Approach 1:
The patent combines the surface processing function with the coating process by adding a surfactant to the coating liquid. This allows depressed portions to be formed during the coating step itself, eliminating the need for separate surface processing steps and thereby improving productivity while maintaining uniformity and fine processing capability.
Solution Approach 2:
The surfactant acts as an intermediary substance that enables the formation of depressed portions on the surface. By controlling the surfactant concentration and properties, the coating liquid can self-organize to create uniform depressed portions with fine processing capability, resolving the contradiction between precision and productivity.
2Adaptability or versatility
If depressed portions are formed by independent surface processing, then surface functionality can be improved, but the preparing method becomes complex and time-consuming
Solution Approach 1:
The patent merges multiple functions (coating and surface pattern formation) into a single process step by incorporating the surfactant in the coating liquid. This reduces process complexity while maintaining the ability to create surfaces with enhanced functionality for electrophotographic applications.
3Productivity
If conventional coating methods are used, then coating can be completed quickly, but dew condensation causes pores and defects on the surface
Solution Approach 1:
The surfactant serves as a mediator that prevents dew condensation during the coating process. By adjusting the surfactant concentration and selecting appropriate surfactants, the coating liquid maintains stability during application and drying, preventing pore formation while allowing rapid coating completion.
Solution Approach 2:
The patent changes the chemical parameters of the coating liquid by adding surfactants with specific concentrations (0.01-5% by mass). This parameter modification prevents dew condensation and pore formation, enabling high-speed coating while maintaining surface quality.
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
This method enables the high-productivity preparation of electrophotographic photosensitive members with stable and controlled depressed portions, improving surface functionality and versatility.
Implementation Method 1
promoting condensation to form depressed portions on the surface
Implementation Method 2
the hydrophilic solvent has a boiling point equal to or higher than that of the hydrophobic solvent and a dipole moment of 0 to 2.8
Data Source
AI summary
A method for preparing in high productivity and stably an electrophotographic photosensitive member having depressed portions on its surface, is provided. The method is characterized in that a coating liquid for a surface layer which includes a solvent including a hydrophilic solvent and a hydrophobic solvent and a polymer compound soluble in the hydrophobic solvent is used; the hydrophilic solvent has a boiling point equal to or higher than that of the hydrophobic solvent; the hydrophilic solvent has a dipole moment of 0 or more and less than 2.8, obtained by a structure optimized calculation using a semiempirical molecular orbital calculation; the total mass of the hydrophobic solvent is 50 mass % or more and less than 100 mass % of the total mass of the solvent included in the coating liquid for a surface layer; and after the coating liquid for a surface layer is applied, the depressed portions are formed by condensation on the surface on which the coating liquid for a surface layer is applied.