Undercoat Layer Curing Control for Photoreceptor Uniformity
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Solution Overview
Problem
Electrophotographic photoreceptors experience a decrease in image density due to residual potential accumulation in the undercoat layer, particularly at the end portions, leading to in-plane nonuniformity after repeated use.
Innovation Solution
An electrophotographic photoreceptor with a cylindrical conductive substrate and an undercoat layer containing a cured product of resin and blocked isocyanate, where the degree of curing is controlled to 1.5 or less in specific regions to suppress residual potential accumulation and charge traps, thereby maintaining image density and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the undercoat layer is highly cured to improve mechanical strength and durability, then the photoreceptor structure becomes more stable, but residual potential accumulates more rapidly leading to image density loss
Solution Approach 1:
The patent applies parameter changes by precisely controlling the degree of curing of the blocked isocyanate in the undercoat layer to be 0.5 or less. This parameter control resolves the contradiction by maintaining mechanical strength while suppressing residual potential accumulation that causes image density loss, thus ensuring both structural stability and image quality reliability.
2Productivity
If repeated use of the photoreceptor continues to maintain productivity, then manufacturing output is sustained, but residual potential accumulation causes in-plane nonuniformity in image density
Solution Approach 1:
The patent applies preliminary action by pre-controlling the degree of curing of the blocked isocyanate in the undercoat layer to 0.5 or less before the photoreceptor enters repeated use. This preliminary control prevents residual potential accumulation from occurring during continuous operation, thereby maintaining both productivity and image density uniformity throughout the photoreceptor's service life.
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 controlled degree of curing in the undercoat layer effectively reduces residual potential and image density loss, enhancing image quality and reducing in-plane nonuniformity even after repeated use.
Implementation Method 1
an undercoat layer containing a cured product of a resin and a blocked isocyanate and having a degree of curing of 0.5 or less
Data Source
AI summary
An electrophotographic photoreceptor includes a cylindrical conductive substrate, an undercoat layer containing a cured product of a resin and a blocked isocyanate and being disposed on the conductive substrate, and a photosensitive layer on the undercoat layer. The degree of curing of the undercoat layer defined by the equation below is about 1.5 or less in both a region A and a region B defined below:Region A (B): A region between a position distant from a first (second) end of the conductive substrate by about ⅛ of a length of the conductive substrate and a position distant from the first (second) end of the conductive substrate by about ⅕ of the length of the conductive substrateDegree of curing=[Amount (g) of blocking agent separated from blocked isocyanate in undercoat layer]/weight of undercoat layer (g)×100.