Electrophotographic Photoconductor Intermediate Layer Surface Treatment
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Solution Overview
Problem
The existing surface-treated metal oxide particles in intermediate layers of electrophotographic photoconductors have insufficient dispersibility in coating solutions, leading to inadequate blocking properties, resulting in issues like image defects such as fogging and dots due to hole injection and carrier leakage.
Innovation Solution
The use of metal oxide particles, specifically titanium oxide, surface-treated with an alkoxysilane oligomer represented by Formula (1) and further treated with reactive silicone oil or alkoxysilane, enhances dispersibility and blocking properties in the intermediate layer, improving electron transportability and reducing image defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal oxide particles are surface-treated with conventional methods (e.g., anhydrous silicon dioxide), then blocking property is improved, but dispersibility in coating solution becomes insufficient
Solution Approach 1:
The patent changes the chemical parameters of the surface treatment by using specific silane coupling agents (KS-150, KS-151, KS-152, KS-153, KS-154) with controlled molecular structures and reaction conditions. This modifies the surface properties of metal oxide particles to achieve both improved dispersibility in coating solutions and sufficient blocking property, resolving the contradiction between these two requirements.
Solution Approach 2:
The patent creates a composite surface structure on metal oxide particles by combining the metal oxide core with silane coupling agent coatings. This composite structure provides both the dispersibility benefits of the silane layer and the blocking properties of the metal oxide, simultaneously satisfying both requirements that were previously contradictory.
2Reliability
If intermediate layer blocking property is insufficient, then hole injection is suppressed, but image defects (fogging and dots) occur due to carrier leakage
Solution Approach 1:
The patent optimizes the surface treatment parameters of metal oxide particles using specific silane coupling agents to achieve the precise blocking property needed. By controlling the surface treatment conditions and silane agent selection, the intermediate layer attains sufficient blocking capability to prevent hole injection while avoiding excessive blocking that would cause carrier leakage and image defects.
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 enhanced intermediate layer with surface-treated metal oxide particles effectively suppresses hole injection and carrier leakage, reducing image defects like fogging and dots, while maintaining sufficient electron transportability.
Implementation Method 1
the metal oxide particles being surface-treated with an alkoxysilane oligomer represented by the following Formula (1)
Implementation Method 2
the negative charges (electrons) migrate through the intermediate layer toward the conductive support
Implementation Method 3
suppress injection of holes from the conductive support to the photosensitive layer (i.e., blocking property)
Implementation Method 4
the metal oxide particles being surface-treated with an alkoxysilane oligomer represented by the following Formula (1)... wherein R1 and R2 each individually represents a C1-4 alkyl group
Data Source
AI summary
The present invention provides an electrophotographic photoconductor including an intermediate layer having sufficient electron transportability and blocking property and capable of suppressing image defects such as fogging and dots. The electrophotographic photoconductor according to the present invention includes a conductive support, a photosensitive layer disposed on the conductive support, and an intermediate layer disposed between the conductive support and the photosensitive layer, wherein the intermediate layer comprises metal oxide particles and a binder resin. The metal oxide particles are surface-treated with an alkoxysilane oligomer represented by the following Formula (1):SinOn-1(OR1)m(OR2)l Formula (1)wherein R1 and R2 each individually represents a C1-4 alkyl group; n represents an integer of 2 to 20; and m and l each individually represents an integer of 0 or more and satisfies an equation of m+1=2n+2.