Organic Photoreceptor Surface Layer for Humidity Stability
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Solution Overview
Problem
Conventional organic photoreceptors face issues with transferability and durability in high humidity environments, leading to uneven halftone images and image deletion due to insufficient surface hardness and mechanical strength, as well as inadequate resistance to abrasion and scratches.
Innovation Solution
Incorporating a surface layer with a photocurable compound containing a polar group and particulate metal oxide particles with low hydrophobicity (0.1-10% water absorption) to enhance curing reaction and reduce water or NOx adsorption, thereby improving layer durability and electrical potential characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a protective layer with high surface hardness is formed through curing reaction, then scratch resistance is improved, but image deletion occurs in unreacted sites due to insufficient curing progress
Solution Approach 1:
The patent changes the chemical parameters of the curing system by introducing a specific photopolymerization initiator (2,4-xylylenedipolyisocyanate) and controlling the curing conditions to achieve complete reaction throughout the protective layer, eliminating unreacted sites that cause image deletion while maintaining high surface hardness
Solution Approach 2:
The patent creates a composite protective layer combining cured resin with inorganic particles (silica, alumina, or titanium oxide) having specific surface areas and hydrophobicity characteristics. This composite structure provides both the mechanical strength for scratch resistance and controlled permeability to prevent image deletion
2Reliability
If metal oxide particles with high hydrophobicity are added to the protective layer, then image deletion is prevented, but surface layer durability decreases and resistance to abrasion or scratch is insufficient
Solution Approach 1:
The patent precisely controls the hydrophobicity parameter of metal oxide particles, selecting particles with a hydrophobicity degree of 30-70 (optimal range) and specific surface area (5-200 m²/g). This parameter optimization prevents image deletion while maintaining sufficient mechanical strength and abrasion resistance
Solution Approach 2:
The patent applies local quality by distributing metal oxide particles with specific properties throughout the protective layer to create regions with enhanced image completeness, while the overall layer composition maintains mechanical durability through the balanced resin matrix and crosslinking structure
3Productivity
If the photoreceptor is used in high temperature and high humidity environment, then productivity is improved, but transferability deteriorates and images become uneven due to insufficient surface hardness
Solution Approach 1:
The patent forms a composite protective layer containing cured resin, inorganic particles (silica, alumina, or titanium oxide) with specific surface areas, and hydrophobic additives. This composite structure provides enhanced surface hardness and dimensional stability that prevents image unevenness even under high temperature and humidity conditions, maintaining both productivity and image quality
Solution Approach 2:
The patent optimizes the crosslinking density and surface composition parameters of the protective layer through controlled photopolymerization and particle selection, creating a surface that resists softening and deformation in high humidity environments, thereby preventing transferability issues and image unevenness
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 enables the production of halftone images without image unevenness or deletion even under severe hygrothermal conditions, with enhanced layer durability and electrical potential characteristics, ensuring stable electrophotographic performance.
Implementation Method 1
a surface layer, wherein the surface layer comprises a resin obtainable by curing a compound having a polar group and a photocurable functional group
Implementation Method 2
a polar group which exists in a relatively high moisture-absorptive region on the metal oxide particle surface, catalytically promotes a curing reaction through interaction with the polar group of a curable compound
Implementation Method 3
after completion of the curing reaction, a polar group attributed to the curable compound captures water or NOx, whereby adsorption of water or NOx is reduced even in relatively high water-absorptive metal oxide particles
Data Source
AI summary
Disclosed is an organic photoreceptor comprising on an electrically conductive support a light-sensitive layer and a surface layer, wherein the surface layer comprises a resin formed by curing a photocurable compound containing at least one polar group and at least one photocurable-functional group and a particulate metal oxide having a water absorption of 0.1 to 10%. There are also disclosed an image forming apparatus and a process cartridge.