Electrophotographic Photosensitive Layer Triboelectric Charge Control
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Solution Overview
Problem
Traditional electrophotographic photosensitive members fail to adequately inhibit the white spot phenomenon, a defect that occurs during image formation due to triboelectric charging and attachment of paper dust.
Innovation Solution
An electrophotographic photosensitive member with a single-layer photosensitive layer containing a charge generating material, an electron transport material represented by a naphthoquinone derivative, a hole transport material, and a binder resin, which generates a triboelectric charge of at least +7 µC/g on calcium carbonate, preventing the attachment of paper dust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electrophotographic photosensitive members are used, then the basic image formation function is achieved, but the white spot phenomenon cannot be sufficiently inhibited
Solution Approach 1:
The patent changes the triboelectric charge parameter of the photosensitive layer by selecting specific electron transport materials (compounds E-1 to E-6) with appropriate molecular structures and substituents. This parameter change ensures the photosensitive layer generates sufficient positive triboelectric charge to repel paper dust, thereby inhibiting the white spot phenomenon while maintaining normal image formation function
Solution Approach 2:
The patent uses composite material structures in the electron transport materials by combining specific molecular frameworks (such as dibenzofuran, dibenzothiophene, carbazole groups) with various substituents (halogen atoms, alkyl groups, aryl groups). This composite approach creates materials with optimized triboelectric properties that effectively prevent paper dust attachment
2Reliability
If the photosensitive layer generates strong positive triboelectric charge to repel paper dust, then the white spot phenomenon is inhibited, but the selection of electron transport material becomes more restricted
Solution Approach 1:
Instead of restricting material selection, the patent establishes specific parameter ranges for electron transport materials (molecular structures containing dibenzofuran, dibenzothiophene, carbazole groups with specific substituents) that naturally generate the required positive triboelectric charge. This transforms the selection constraint into a structured design guideline
Solution Approach 2:
The patent applies local quality by introducing specific functional groups and substituent patterns at particular positions within the electron transport material molecules. These localized structural features (such as halogen atoms at specific positions, alkyl group configurations) are what generate the required triboelectric properties, allowing systematic material design rather than broad restriction
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 solution effectively inhibits the occurrence of the white spot phenomenon by maintaining a strong electrostatic repelling force against paper dust, ensuring higher image quality and reduced defects.
Implementation Method 1
An amount of triboelectric charge of calcium carbonate as measured by charging the calcium carbonate through friction with the photosensitive layer is at least +7 μC/g
Implementation Method 2
The light exposure device irradiates the charged surface of the image bearing member with light to form an electrostatic latent image on the surface of the image bearing member
Implementation Method 3
The transfer device transfers the toner image from the surface of the image bearing member to a recording medium while in contact with the surface of the image bearing member
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
An electrophotographic photosensitive member (1) includes a conductive substrate (2) and a photosensitive layer (3). The photosensitive layer (3) is a single-layer photosensitive layer containing at least a charge generating material, an electron transport material, a hole transport material, and a binder resin. The electron transport material includes a naphthoquinone derivative represented by general formula (1). An amount of triboelectric charge of calcium carbonate as measured by charging the calcium carbonate through friction with the photosensitive layer (3) is at least +7 µC/g. In general formula (1), R11 and R12 are respectively the same as R11 and R12 described in the description.