Strontium Titanate Undercoat Layer for Ghost Image Suppression
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Solution Overview
Problem
Existing electrophotographic photosensitive members face challenges in reducing residual potential and preventing ghost images, especially in low-humidity environments, due to limitations in the electrical properties of undercoat layers containing metal oxide particles.
Innovation Solution
Incorporating strontium titanate particles with a specific X-ray diffraction pattern and titanium oxide particles in the undercoat layer, where the strontium titanate has a maximum peak at 2θ=32.20±0.20 in a CuKα characteristic X-ray diffraction pattern and a half-value width of 0.10 deg or more and 0.50 deg or less, along with a polyvinyl butyral resin in the photosensitive layer, to enhance electrical properties and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal oxide particles (e.g., dendrite-shaped titanium oxide) are used in the undercoat layer, then residual potential can be reduced in low-humidity environments, but ghost images still occur and electrical properties are insufficient
Solution Approach 1:
The patent applies composite materials by combining strontium titanate particles and titanium oxide particles in the undercoat layer. This composite structure leverages the high electrical conductivity of strontium titanate to reduce residual potential and suppress ghost images, while the titanium oxide provides additional electrical property enhancement. The synergistic effect of these two materials resolves the contradiction between reducing residual potential and preventing ghost images.
Solution Approach 2:
The patent changes the particle size parameter of the metal oxide particles to 10 μm or less, which optimizes the electrical properties of the undercoat layer. This parameter change enhances charge dissipation capability, thereby reducing residual potential and preventing ghost image formation while maintaining reliable electrophotographic performance in low-humidity environments.
2Reliability
If the undercoat layer uses metal oxide particles with optimized electrical properties, then residual potential is reduced, but adhesion between layers may be compromised
Solution Approach 1:
The patent applies local quality by using polyvinyl butyral resin specifically in the photosensitive layer, which provides excellent adhesion to the undercoat layer containing metal oxide particles. This localized use of adhesive resin ensures strong interlayer bonding while allowing the undercoat layer to maintain its optimized electrical properties for residual potential reduction.
Solution Approach 2:
The combination of polyvinyl butyral resin with metal oxide particles creates a composite structure that balances adhesion and electrical properties. The resin matrix provides binding strength between layers, while the dispersed metal oxide particles maintain the electrical conductivity needed for residual potential control.
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
This configuration effectively suppresses residual potential and prevents ghost image formation in low-humidity environments while maintaining sufficient adhesion between layers, improving the overall performance of the electrophotographic photosensitive member.
Implementation Method 1
the strontium titanate particle has a maximum peak at a position of 2θ=32.20±0.20 (θ represents a Bragg angle) in a CuKα characteristic X-ray diffraction pattern
Data Source
AI summary
There is provided an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus in which residual potential is suppressed and a ghost image is prevented from being generated in a low-humidity environment in an undercoat layer of the electrophotographic photosensitive member. An electrophotographic photosensitive member including: an undercoat layer containing a strontium titanate particle having a maximum peak at a position of 2θ=32.20±0.20 (θ represents a Bragg angle) in a CuKα characteristic X-ray diffraction pattern and a half-value width of the maximum peak of 0.10 deg or more and 0.50 deg or less, and a titanium oxide particle; and a photosensitive layer containing a polyvinyl butyral resin, and a process cartridge and an electrophotographic apparatus each provided with the electrophotographic photosensitive member.