Toner Particle Size Distribution for Image Stability
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Solution Overview
Problem
Conventional toners with large amounts of fine powder suffer from issues such as soiling, image defects, and poor image quality due to non-uniform particle size distribution, leading to problems like ghosting, blurring, and decreased image stability, especially in high-speed printing.
Innovation Solution
An image forming apparatus using a toner with a specific particle size distribution, where the volume median diameter is between 4.0 μm and 7.0 μm, and the percentage of particles between 2.00 μm and 3.56 μm satisfies a specific formula, combined with an electrophotographic photoreceptor having a polyamide resin undercoat layer, metal oxide particles, or a curable resin, to enhance image quality and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If toner particle size is reduced to improve resolution and reproducibility of fine dots, then image sharpness and fine line reproduction improve, but image tends to be poor in gradation and sharpness due to mismatching between dot units and toner positions
Solution Approach 1:
The patent applies parameter changes by precisely controlling toner particle size distribution parameters. Specifically, it sets the volume average particle diameter between 4.0-7.0 μm and controls the percentage of particles in the 2.00-3.56 μm range to satisfy a specific formula, thereby optimizing both fine dot reproduction and image quality stability without requiring further particle size reduction
2Ease of manufacture
If conventional toner with large amount of fine powder is used, then particle size distribution is broad, but this leads to soiling, image defects, ghosting, blurring, and decreased image stability
Solution Approach 1:
The patent applies local quality by creating a non-uniform particle size distribution where different particle size ranges serve different functions. The controlled distribution ensures that fine particles (2.00-3.56 μm) are present in specific proportions to maintain flowability and filling properties, while limiting excessive fine powder that causes soiling and image defects
Solution Approach 2:
The patent changes the particle size distribution parameters by setting the volume average particle diameter between 4.0-7.0 μm and controlling the percentage of particles in the 2.00-3.56 μm range to satisfy a specific formula, thereby eliminating soiling and image defects while maintaining manufacturing flexibility
3Manufacturing precision
If dot size is reduced to improve resolution, then fine line reproduction capability improves, but the reproducibility of latent image becomes further difficult and image tends to be poor in gradation
Solution Approach 1:
The patent applies parameter changes by optimizing the volume average particle diameter to 4.0-7.0 μm and controlling the particle size distribution to satisfy a specific formula for the percentage of particles in the 2.00-3.56 μm range. This optimization enables adequate toner coverage and gradation reproduction while maintaining high resolution capability
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 effectively suppresses soiling and image defects, improves fixing properties, and maintains image stability even in high-speed printing, with a narrow particle size distribution reducing air content and enhancing thermal insulation and heat capacity.
Implementation Method 1
a photoreceptor and a toner for developing an electrostatic charge image
Implementation Method 2
electrification is done instantaneously by friction as in a non-magnetic one component developing method
Data Source
AI summary
A method of forming an image including an electrophotographic photoreceptor and a toner, wherein a photosensitive layer in the electrophotographic photoreceptor includes an undercoat layer including metal oxide particles, a charge generation layer including hydroxygallium phthalocyanine, and a charge transport layer, and the toner contains toner matrix particles formed in an aqueous medium; the toner has a volume median diameter (Dv50) of from 4.0 μm to 7.0 μm; and the relationship between the volume median diameter (Dv50) and the percentage in number (Dns) of toner particles having a particle diameter of from 2.00 μm to 3.56 μm satisfies—0.0517EXP(22.4/Dv50)≦Dns≦0.233EXP(17.3/Dv50) where Dv50 is the volume median diameter (μm) of the toner, and Dns is the percentage in number of toner particles having a particle diameter of from 2.00 μm to 3.56 μm.