Electrophotographic Photoreceptor Intermediate Layer Hardness
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Solution Overview
Problem
Electrophotographic photoreceptors experience peeling of layers at the end part where an abutting member contacts, despite the use of an undercoat layer to improve image quality, due to stress-induced strain between layers.
Innovation Solution
Incorporating an intermediate layer with a Martens hardness of 500 N/mm2 or less between specific layers in the photoreceptor, particularly in the region abutting the spacing member, to relieve stress and prevent peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an undercoat layer containing a polymer of a composition containing an electron transport material and a crosslinking agent is used, then image quality is improved and positive ghosts are prevented, but layer peeling occurs at the abutting portion due to stress-induced strain
Solution Approach 1:
The photoreceptor is divided into a first portion (image forming region) and a second portion (abutting region), with the undercoat layer selectively applied only to the first portion. This segmentation allows the undercoat layer to improve image quality in the image forming region while avoiding the layer peeling problem in the abutting region where stress concentrates.
Solution Approach 2:
The undercoat layer is applied locally only to the first portion of the photoreceptor surface, not uniformly across the entire surface. This local quality approach ensures that the benefits of the undercoat layer (improved image quality and positive ghost prevention) are achieved where needed, while avoiding the harmful effects (layer peeling) in the abutting portion.
2Reliability
If the photoreceptor structure is simplified without an undercoat layer, then layer peeling is reduced, but image quality deteriorates and positive ghosts form
Solution Approach 1:
The photoreceptor structure is segmented such that the undercoat layer is present only in the first portion (image forming region) and absent in the second portion (abutting region). This segmentation resolves the contradiction by providing layer stability in the abutting region while maintaining image quality in the image forming region.
Solution Approach 2:
The undercoat layer configuration is optimized locally for different functional regions: present and optimized for image quality in the first portion, and absent or minimized in the second portion to prevent peeling. This local differentiation allows both requirements to be satisfied simultaneously.
3Ease of operation
If the photoreceptor abuts against the charging member or developer carrying member, then the electrophotographic process is enabled, but stress-induced strain causes layer peeling at the abutting portion
Solution Approach 1:
The photoreceptor is segmented into an image forming region (first portion) and an abutting region (second portion), with the undercoat layer selectively applied to the first portion. This segmentation allows the abutting operation to proceed while preventing stress-induced peeling by avoiding the undercoat layer in the high-stress abutting region.
Solution Approach 2:
The undercoat layer is applied with local quality differentiation: fully present in the first portion for optimal image forming, and absent or reduced in the second portion where abutting stress occurs. This local adaptation enables both functional operation and reliability.
Data Source
AI summary
An electrophotographic photoreceptor abuts against a charging member and/or a developer carrying member with an abutting member therebetween, has a first portion and a second portion abutting against the abutting member along the longitudinal direction of the photoreceptor, and includes a support, a charge generating layer containing a charge generation material, and a surface layer in this order. The first portion includes an undercoat layer containing a polymer of a composition containing an electron transport material and a crosslinking agent and being contiguous with the surface of the charge generating layer facing the support. The second portion includes (i) an intermediate layer being disposed between and being contiguous with the support and the charge generating layer and/or (ii) an intermediate layer being disposed between and being contiguous with the charge generating layer and the surface layer, wherein the intermediate layers each have a Martens hardness of 500 N/mm2 or less.