Developing Roll Surface Brightness and Roughness for Toner Cleaning
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Solution Overview
Problem
The existing image forming methods using electrophotographic systems face challenges in efficiently removing toner containing spherical and small-sized colored resin particles from the photosensitive member, particularly under varying environmental conditions, leading to poor cleaning performance and image quality issues.
Innovation Solution
The method involves modifying the surface characteristics of the developing roll and using a cleaning blade made of polyurethane elastomer with specific viscoelastic properties, along with controlling the charge level and pH of the toner, to effectively remove the toner remaining on the photosensitive member, ensuring high-definition and high-quality image formation across different environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a cleaning blade is used to remove toner remaining on the photosensitive member, then the cleaning process is simple, but the cleaning ability is poor when using toner with spherical and small-sized colored resin particles
Solution Approach 1:
The invention changes the surface characteristics parameters of the developing roll by controlling surface brightness (30-220) and surface roughness Rz (1-20 μm). These parameter modifications enable effective cleaning of spherical and small-sized colored resin particles while maintaining simple cleaning process architecture.
Solution Approach 2:
The invention uses a composite cleaning system combining a developing roll with specific surface properties and a cleaning blade made of polyurethane elastomer. The polyurethane elastomer cleaning blade has specific viscoelastic properties (peak value of viscoelasticity tan δ of at most 0.95, peak temperature from -15 to 10°C) that enable effective cleaning while maintaining process simplicity.
2Manufacturing precision
If spherical and small-sized colored resin particles are used in toner, then high-resolution images can be formed, but the toner is difficult to clean off the photosensitive member
Solution Approach 1:
The invention modifies the surface brightness and surface roughness parameters of the developing roll to specific ranges (brightness: 30-220, Rz: 1-20 μm) that enable effective removal of spherical and small-sized colored resin particles while preserving the image quality benefits of using such particles.
Solution Approach 2:
The invention introduces a cleaning blade made of polyurethane elastomer as an intermediary cleaning agent. This cleaning blade with specific viscoelastic properties acts as a mediator between the spherical and small-sized colored resin particles and the cleaning process, enabling effective removal without compromising image resolution.
3Reliability
If the surface brightness and roughness of the developing roll are controlled within specific ranges, then cleaning ability is improved, but the device manufacturing complexity increases
Solution Approach 1:
The invention specifies concrete parameter ranges for surface brightness (30-220) and surface roughness Rz (1-20 μm) that can be achieved through conventional developing roll manufacturing processes. These parameters balance cleaning effectiveness with manufacturability, avoiding excessive complexity while ensuring reliable cleaning performance.
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 significantly enhances the cleaning ability and image quality by effectively removing toner residues, maintaining high printing density and durability even under low-temperature and low-humidity, high-temperature and high-humidity, and normal environmental conditions.
Implementation Method 1
a cleaning step of removing the toner remaining on the surface of the photosensitive member after the transfer step by means of a cleaning blade brought into contact with the surface of the photosensitive member
Implementation Method 2
a cleaning blade made of a polyurethane elastomer and having a peak value of viscoelasticity tan δ of at most 0.95, a peak temperature of viscoelasticity tan δ from −15 to 10° C. and a width at half maximum of viscoelasticity tan δ of at least 25° C.
Data Source
AI summary
In an image forming method including a charging step, an exposure step, a development step using a developing roll, a transfer step, a fixing step and a cleaning step of removing a toner remaining on the surface of a photosensitive member after the transfer step, the developing roll has a surface brightness of 30 to 220 and a surface roughness Rz of 1 to 20 μm, the cleaning blade is a cleaning blade made of a polyurethane elastomer and having a peak value of at most 0.95, a peak temperature of −15 to 10° C. and a width at half maximum of at least 25° C. in viscoelasticity tan δ, the toner has a volume average particle diameter of 4 to 10 μm and an average circularity from 0.950 to 0.995, the charge level of the toner on the surface of the photosensitive member is 10 to 80 μC/g in terms of an absolute value, and the pH of a water extract of the toner is 3 to 8.