Electrophotographic Carrier With Flat Chargeable Particles
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Solution Overview
Problem
Electrophotographic image forming methods face challenges in maintaining high image quality and charge stability over an extended period, with issues such as 'ghost image' phenomena and contamination due to chargeable particle separation from the coating layer.
Innovation Solution
A carrier with a core particle and a coating layer containing flat chargeable particles, where the core particle has an internal void ratio of 0.0% to 2.0% and an apparent density of 2.0 to 2.5 g/cm3, and the flat chargeable particles have a specific ratio of major axis to thickness, preventing separation and maintaining chargeability and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional carriers are used, then initial image quality can be achieved, but charge stability and image quality deteriorate over extended periods due to particle separation and contamination
Solution Approach 1:
The carrier uses a composite structure with a core particle and a coating layer containing flat chargeable particles. This composite design prevents particle separation by embedding the chargeable particles within the coating layer matrix, maintaining charge stability throughout the carrier's service life and eliminating ghost image phenomena that occur with conventional single-material carriers.
2Reliability
If chargeable particles are used in the coating layer, then chargeability is maintained, but particles separate from the coating layer over time causing contamination
Solution Approach 1:
The coating layer is designed with specific local properties where flat chargeable particles are embedded within a resin matrix. The local composition and structure of the coating layer are optimized to hold the chargeable particles firmly while maintaining their chargeability, preventing separation and contamination during the carrier's operation.
3Manufacturing precision
If high image quality is pursued, then detailed image reproduction is achieved, but ghost image phenomena occur over time
Solution Approach 1:
The patent converts the potential harm of particle separation into a benefit by using a coating layer structure that inherently prevents separation. The flat chargeable particles embedded in the coating layer maintain stable charge distribution, which eliminates ghost image phenomena while preserving high image quality reproduction throughout the carrier's service life.
Data Source
AI summary
A carrier for developing an electrostatic latent image is provided. The carrier comprises a core particle having an internal void ratio of from 0.0% to 2.0% and a coating layer coating the core particle. The coating layer contains flat chargeable particles satisfying Formula 1 blow:1.0≤R1/R2≤3.0 Formula 1where R1 [nm] and R2 [nm] represent a major axis and a thickness, respectively, of each of the flat chargeable particles. The carrier has an apparent density of from 2.0 to 2.5 g/cm3.