Crosslinked Resin Protective Layer for Electrophotographic Photoreceptor
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Solution Overview
Problem
Electrophotographic photoreceptors in image forming apparatuses face issues such as pinhole leaks, image ghosting, and transfer ghosting due to the contact charging system and the use of spherical polymerization toners, which lead to abrasion and reduced lifespan, especially when using intermediate transfer media.
Innovation Solution
An electrophotographic photoreceptor with a conductive support and a photosensitive layer having a crosslinked resin protective layer as the outermost surface, which absorbs exposure light with a maximum absorbance of 0.05 or less across the entire wavelength range, reducing residual potential and ghosting phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a contact charging system is used to charge the photoreceptor surface, then the apparatus can be miniaturized and harmful gas generation is reduced, but deterioration and abrasion of the photoreceptor occur due to direct electric discharge
Solution Approach 1:
A protective layer is introduced as an intermediary between the contact charging member and the photoreceptor surface. This protective layer prevents direct electric discharge from damaging the photoreceptor, reducing deterioration and abrasion while maintaining the miniaturization benefits of the contact charging system.
2Duration of action of moving object
If the photoreceptor is repeatedly used for a long period of time with contact charging, then high electric field is locally applied to defect parts causing pinhole leaks, but image quality deteriorates due to image defect generation
Solution Approach 1:
The protective layer serves as a cushioning layer applied beforehand to the photoreceptor surface. It prevents high electric fields from concentrating at defect parts during repeated use, thereby preventing pinhole leaks and maintaining image quality over extended usage periods.
3Strength
If a crosslinked resin protective layer with charge transporting property is applied to the photoreceptor surface, then mechanical strength is enhanced and lifespan is extended, but residual potential occurs due to controlled charge transporting property
Solution Approach 1:
The charge transporting property of the protective layer is precisely controlled by adjusting the density and type of polar groups at crosslinking terminals. This parameter optimization allows the protective layer to provide mechanical strength while minimizing residual potential generation, resolving the contradiction between strength and reliability.
4Manufacturing precision
If spherical polymerization toners are used to obtain high image quality, then image quality improves, but toners pass through blade cleaner during removal requiring closer pressing against photoreceptor
Solution Approach 1:
The protective layer acts as an intermediary between the spherical polymerization toners and the blade cleaner. It provides a surface that allows effective toner removal while reducing the pressing force required, thereby preventing photoreceptor abrasion despite using spherical toners for high image quality.
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 enhances mechanical strength, reduces ghosting and pinhole leaks, and extends the lifespan of the photoreceptor by minimizing residual potential and improving transfer efficiency.
Implementation Method 1
the outermost surface layer of the electrophotographic photoreceptor absorbing exposure light of the second exposure unit and having a maximum absorbance of about 0.05 or less in the entire wavelength range of the exposure light of the second exposure unit
Data Source
AI summary
An image forming apparatus includes: an electrophotographic photoreceptor including a conductive support and a photosensitive layer including an outermost surface layer capable of transporting a charge, the layer being farthest from the conductive support and containing a resin having a crosslinking structure; a charging unit that charges the electrophotographic photoreceptor; a first exposure unit that exposes the electrophotographic photoreceptor to form an electrostatic latent image on the electrophotographic photoreceptor charged; a developing unit that develop the electrostatic latent image with a toner to form a toner image; a transfer unit that transfer the toner image from the electrophotographic photoreceptor to a medium to be transferred; and a second exposure unit that uniformly expose the electrophotographic photoreceptor, the outermost surface layer absorbing exposure light of the second exposure unit and having a maximum absorbance of about 0.05 or less in the entire wavelength range of the exposure light.