Developing Roller Toner Film Prevention
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Solution Overview
Problem
Electrophotographic image forming apparatuses using trail type regulating blades face challenges in minimizing the size of the developing unit while maintaining a long life span and preventing toner filming due to high contact forces, which can lead to reduced image quality and shorter unit lifespan.
Innovation Solution
The implementation of a trail type regulating blade with a specific toner diameter distribution, an elastic rubber layer on the developing roller, and timely toner supply to maintain a uniform toner layer and prevent filming, ensuring the developing unit's longevity and efficient image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a trail type regulating blade is used to minimize the size of the developing unit, then the apparatus size is reduced, but the contact force with the developing roller increases causing toner filming and reduced lifespan
Solution Approach 1:
The patent applies parameter changes by carefully controlling the toner particle size distribution (limiting particles ≤1/2 Dv50 to ≤15% in number-diameter distribution) and regulating blade characteristics to modify the interaction parameters between toner and blade, thereby reducing toner filming while maintaining the compact trail type configuration
Solution Approach 2:
The patent applies local quality by creating a uniform toner layer with controlled thickness through the regulating blade, ensuring consistent toner properties at the contact point between the blade and developing roller, which prevents localized toner accumulation and filming
2Volume of moving object
If a trail type regulating blade is used to minimize the size of the developing unit, then the apparatus size is reduced, but toner filming occurs due to higher contact forces
Solution Approach 1:
The patent changes the toner particle size distribution parameters to limit fine particles (≤1/2 Dv50) to ≤15% in number-diameter distribution, which reduces toner filming tendency while maintaining the compact trail type regulating blade configuration
Solution Approach 2:
The patent converts the potential harm of high contact forces in trail type configuration into a benefit by optimizing toner layer uniformity through controlled particle distribution, where the regulated uniform toner layer prevents filming despite the higher contact forces
3Volume of moving object
If a trail type regulating blade is used, then the size of the developing unit is minimized, but image quality deteriorates due to toner filming
Solution Approach 1:
The patent applies parameter changes by controlling toner particle size distribution (≤15% of particles with diameter ≤1/2 Dv50 in number-diameter distribution) to prevent toner filming, thereby maintaining high image quality in the compact trail type developing unit
Solution Approach 2:
The patent ensures local quality by creating a uniform toner layer through the regulating blade with controlled thickness, which maintains consistent toner properties across the image formation area and prevents localized filming that would degrade 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
This approach enables the reliable printing of high-quality images for a longer period, extends the life span of the developing unit, and minimizes the size of the image forming apparatus, reducing costs associated with expendable supplies.
Implementation Method 1
an elastic rubber layer having a thickness of not less than about 0.5 mm and not more than about 60% of the radius of the developing roller and a resistance between about 105-1011 Ω/cm is provided on a surface of the developing roller
Implementation Method 2
A trail type regulating blade is installed to form a uniform toner layer on the developing roller
Implementation Method 3
A developing unit develops the electrostatic latent image by supplying non-magnetic mono-component toner to the electrostatic latent image
Data Source
AI summary
An electrophotographic image forming apparatus is provided which includes an image receptor on which an electrostatic latent image is formed. A developing unit develops the electrostatic latent image by supplying non-magnetic mono-component toner to the electrostatic latent image and includes a developing roller which faces the image receptor. A trail type regulating blade is installed to form a uniform toner layer on the developing roller. In the electrophotographic image forming apparatus, the rate of the amount of toner particles having a diameter of not more than about half of a median value of a volume-diameter distribution of the toner is not more than about 15% in a number-diameter distribution.