Counter-Development Toner and Photoreceptor for Image Density
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Solution Overview
Problem
Existing electrophotographic image forming methods, particularly the counter-development system, face issues with fogging, insufficient density, and non-uniform image formation due to the formation of reversely charged toner and contact friction between the organic photoreceptor and developer, leading to degraded image quality.
Innovation Solution
The use of a flat toner with a circle equivalent diameter of 3.0 to 8.0 μm and a flatness ratio of 2.0 to 5.0, combined with an organic photoreceptor having a surface layer with inorganic particles, where the developing sleeve is rotated in the opposite direction to the photoreceptor, minimizes the formation of reversely charged toner and improves adhesion properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a developing sleeve is advanced parallel to the advancing direction of the photoreceptor, then the development process is simple, but developability of the periphery of images suffers resulting in insufficient density
Solution Approach 1:
The patent applies the inversion principle by reversing the developing sleeve rotation direction to oppose the photoreceptor rotation direction. This counter-development approach allows the developing sleeve to maintain optimal contact pressure and position throughout the development region, thereby improving peripheral image density and overall developability while maintaining operational simplicity
2Manufacturing precision
If a developing sleeve is advanced in the opposite direction to the photoreceptor, then high density dot images can be formed, but fogging and insufficient density at the leading edge occur
Solution Approach 1:
The patent applies parameter changes by optimizing the flatness ratio of toner particles (d/t) within the range of 2.0 to 5.0 and controlling particle size distribution. This modifies the physical parameters of the developer to reduce harmful friction effects and reverse charge generation, thereby minimizing fogging and leading edge density issues while maintaining high image density
Solution Approach 2:
The patent uses composite materials by combining flattened toner particles with specific carrier properties and incorporating inorganic particles in the photoreceptor surface layer. This composite approach creates a synergistic effect that reduces reverse charging and improves overall development uniformity, eliminating fogging and leading edge defects
3Manufacturing precision
If flattened toner particles are used to increase shielding effect, then high density images can be prepared, but toner easily adheres to carrier resulting in degraded developability
Solution Approach 1:
The patent applies parameter changes by precisely controlling the flatness ratio (d/t) within 2.0 to 5.0 and optimizing particle size distribution. This balanced parameter selection provides sufficient shielding effect for high density images while preventing excessive adhesion to the carrier, thereby maintaining good developability
Solution Approach 2:
The patent uses an intermediary approach by introducing inorganic particles in the photoreceptor surface layer and optimizing carrier properties. This intermediary layer and carrier modification act as a buffer between the flattened toner and the photoreceptor surface, reducing direct adhesion while maintaining the shielding effect for high density image formation
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 approach stabilizes the formation of high-density, detailed digital images with reduced fog and toner scattering, enhancing image quality and color reproduction by minimizing density decreases at the leading edge and improving developability.
Implementation Method 1
Most of electrophotographic photoreceptors have been shifted from inorganic photoreceptors to organic photoreceptors... a conductive support having thereon a surface layer incorporating inorganic particles
Implementation Method 2
developing an electrostatic latent image on an organic photoreceptor by a developer on a developing sleeve to form a toner image on the photoreceptor
Data Source
AI summary
An electrophotographic image forming method is disclosed. The method contains steps of forming an electrostatic latent image on an organic photoreceptor, and developing the electrostatic latent image by a developer containing toner to form a toner image on the photoreceptor. In this method the photoreceptor contains inorganic particles in a surface layer, the toner has circle equivalent diameter d of 3.0 to 8.0 μm viewed from a direction which maximizes the projective area of toner particles, the toner has a flatness ratio d/t of 2.0 to 5.0, wherein d is circle equivalent diameter and t is average thickness of toner particles, and the electrostatic latent image is developed in such a manner that the developing sleeve is rotated in the opposite direction to the photoreceptor.