Photoreceptor Charge Transport Layer Hardness for Filming Suppression
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Solution Overview
Problem
Existing electrophotographic photoreceptors face issues with filming and abrasiveness, particularly when using lamination or single layer type photosensitive layers, due to the embedding of toner external additives, leading to surface deformation and deterioration.
Innovation Solution
The photoreceptor incorporates a charge transport layer or single layer type photosensitive layer containing a resin such as polyester or polycarbonate, with specific hardness and elastic modulus ranges defined by Relational Equation (0) to suppress filming while maintaining low abrasiveness, using a conductive substrate with optional undercoat and interlayer configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lamination type photosensitive layer or single layer type photosensitive layer is used, then the photoreceptor can achieve basic imaging function, but filming occurs and abrasiveness increases due to embedding of toner external additives
Solution Approach 1:
The patent applies parameter changes by precisely controlling the hardness (HM: 120-300 N/mm²) and elastic deformation modulus (45-70%) of the charge transport layer, along with the indentation hardness (nIT: 150-600 N/mm²). These parameter optimizations prevent toner external additives from embedding into the layer, thereby suppressing filming while maintaining low abrasiveness and improving overall reliability
Solution Approach 2:
The patent employs composite materials by formulating the charge transport layer with specific resins (polyester or polycarbonate) combined with charge transport substances. This composite structure provides both the mechanical properties needed to resist toner embedding and the electrical properties required for charge transport, effectively addressing both filming suppression and abrasiveness concerns
2Reliability
If the charge transport layer has high hardness to prevent toner embedding, then filming is suppressed, but abrasiveness increases
Solution Approach 1:
The patent resolves this contradiction through parameter changes by establishing an optimal balance between hardness (HM: 120-300 N/mm²) and elastic deformation modulus (45-70%). This balanced parameter set provides sufficient resistance to toner embedding for filming suppression while maintaining low abrasiveness, avoiding the need for excessive hardness
3Stability of the object's composition
If the elastic deformation modulus is increased to maintain layer integrity, then structural stability improves, but filming and abrasiveness worsen
Solution Approach 1:
The patent applies parameter changes by optimizing the elastic deformation modulus to a specific range (45-70%) that simultaneously ensures layer integrity and prevents toner embedding. This balanced parameter selection achieves both structural stability and filming suppression without compromise
Data Source
AI summary
An electrophotographic photoreceptor includes a conductive substrate, and a lamination type photosensitive layer disposed on the conductive substrate and including a charge generation layer and a charge transport layer in this order, in which the charge transport layer contains at least one resin selected from a polyester resin or a polycarbonate resin, and in a case where a Martens hardness and an indentation hardness, which are acquired by an indentation test performed on the charge transport layer to a depth of 0.5 μm, are respectively defined as HM (N/mm2) and nIT (N/mm2), Relational Equation (0) is satisfied, an elastic deformation modulus is 45% or greater and 70% or less, and a tensile elastic modulus of the charge transport layer is 2,300 MPa or greater and 5,000 MPa or less,nIT=a×HM−b(a=2±0.2,b=100±20). (0)