Conductive Substrate Waviness Control for Image Density Uniformity
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Solution Overview
Problem
The use of conductive substrates with waviness in the axial direction in electrophotographic photoreceptors leads to banded inconsistencies in image density due to interference between variations in exposure intensity and substrate waviness, particularly when used in image-forming apparatuses with light sources arranged in the axial direction.
Innovation Solution
The mean width of the waviness profile of the conductive substrate is controlled to be smaller than the arrangement interval of the light sources, reducing the likelihood of interference and thus minimizing banded inconsistencies in image density, by optimizing the machining process and using specific treatments like acidic and boehmite treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the outer periphery of the conductive substrate is formed by machining, then the substrate can be manufactured with required dimensions, but helical traces of machining remain causing waviness in the axial direction
Solution Approach 1:
The patent applies surface treatment processes (acidic treatment and boehmite treatment) to change the surface parameters of the conductive substrate. These treatments modify the surface morphology to reduce waviness amplitude while maintaining the underlying dimensional accuracy achieved through machining.
Solution Approach 2:
The surface treatment processes are applied as preliminary actions before the electrophotographic layers are formed on the substrate. By treating the surface in advance, the waviness is reduced prior to layer formation, preventing the transfer of surface irregularities to the final product.
2Ease of manufacture
If an electrophotographic photoreceptor with waviness in the axial direction is used, then the photoreceptor can be manufactured, but banded inconsistencies in image density occur due to interference with light source exposure
Solution Approach 1:
The patent changes the surface parameters of the conductive substrate through acidic and boehmite treatments, reducing the amplitude of waviness to a level where it no longer causes banded inconsistencies in image density during exposure with plural light sources arranged in the axial direction.
Solution Approach 2:
The patent converts the harmful effect of machining-induced waviness into a beneficial outcome by applying surface treatments that control the waviness parameters. The treatment process transforms the rough, wavy surface into one with controlled micro-irregularities that do not interfere with exposure uniformity while maintaining manufacturing feasibility.
3Manufacturing precision
If surface treatment processes are applied to reduce waviness, then image density uniformity is improved, but additional manufacturing steps are required
Solution Approach 1:
The patent employs surface treatment processes (acidic treatment and boehmite treatment) that, while adding manufacturing steps, provide significant improvement in image density uniformity by controlling waviness parameters. These treatments are integrated into the existing manufacturing workflow to minimize overall process complexity.
Data Source
AI summary
An image-forming apparatus includes an electrophotographic photoreceptor including a conductive substrate and a photosensitive layer disposed on the conductive substrate; a charging device that charges a surface of the photoreceptor; an exposure device that forms an electrostatic latent image on the surface of the photoreceptor by irradiating the surface of the photoreceptor with light, the exposure device including plural light sources arranged in an axial direction of the photoreceptor; a developing device including a developer including a toner which forms a toner image by developing the electrostatic latent image with the developer; and a transfer device that transfers the toner image to a recording medium. A mean width WSm of waviness profiles of an outer periphery of the conductive substrate determined in accordance with JIS B0601 (2001) is smaller than an interval at which the light sources are arranged in the axial direction of the photoreceptor.