Electrophotographic Photoreceptor Surface Layer Composite
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Solution Overview
Problem
Electrophotographic photoreceptors used in proximity charging-type image forming apparatuses face challenges in achieving balanced wear resistance, transfer memory resistance, image deletion resistance, and durability due to surface layer deterioration from electric discharge and contamination issues.
Innovation Solution
An electrophotographic photoreceptor with a surface layer containing a charge transport material, surface-treated inorganic fine particles with high volume resistivity, and organic fine particles, such as melamine-formaldehyde condensation resin particles, which improves wear resistance, transfer memory resistance, and image deletion resistance by reducing electric discharge impact and toner adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the photoreceptor uses a surface layer with low-resistance metal oxide particles to reduce wear, then wear resistance is improved, but torque increases and cleanability deteriorates
Solution Approach 1:
The surface layer uses a composite material system consisting of inorganic fine particles (metal oxide, silica, or alumina) combined with organic fine particles (melamine-formaldehyde condensation resin particles) and a binder resin. This composite structure provides both wear resistance from the inorganic particles and controlled electrical properties from the organic components, avoiding the torque issues associated with low-resistance metal oxide particles while maintaining cleanability.
2Ease of operation
If the photoreceptor uses melamine-formaldehyde condensation resin particles to improve cleanability, then cleanability is improved, but wear resistance and transfer memory resistance are insufficient
Solution Approach 1:
The surface layer combines organic fine particles (melamine-formaldehyde condensation resin particles) with inorganic fine particles (metal oxide, silica, or alumina) having specific surface treatments and controlled volume resistivity. The inorganic particles provide wear resistance and transfer memory resistance, while the organic particles maintain cleanability, creating a synergistic composite structure that achieves all required properties simultaneously.
3Reliability
If the inorganic fine particles have high volume resistivity to reduce electric discharge impact, then transfer memory resistance is improved, but image deletion resistance may deteriorate
Solution Approach 1:
The inorganic fine particles are controlled to have a specific volume resistivity range (1.0×10^11 to 1.0×10^16 Ω·cm) and undergo surface treatment with silane coupling agents. This parameter optimization allows the particles to provide sufficient transfer memory resistance while the surface treatment and combination with organic fine particles prevent excessive charge accumulation that would cause image deletion, achieving a balanced electrical property profile.
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 proposed configuration enhances the photoreceptor's ability to maintain excellent image quality over time by preventing surface layer deterioration, reducing toner adhesion, and efficiently removing discharge products, thereby achieving improved wear resistance, transfer memory resistance, and durability.
Implementation Method 1
surface layer deterioration from electric discharge
Implementation Method 2
a cured product of a composition containing a polymerizable compound and inorganic fine particles
Data Source
AI summary
An electrophotographic photoreceptor for use in an image forming apparatus having a proximity charge-type charging unit includes a conductive support and at least photosensitive layer and surface layer laminated in order on the conductive support, wherein the surface layer includes (A) a charge transport material, (B) a cured product of a composition containing a polymerizable compound and inorganic fine particles, and (C) organic fine particles, and the inorganic fine particles contain a metal oxide, has a surface treated with a surface treatment agent having a reactive organic group, and has a volume resistivity of 1.2×1011Ω·cm or more.