Developing Unit Resin Particles Prevent Banding
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Solution Overview
Problem
The existing developing units in electrophotographic apparatuses suffer from 'banding' issues in halftone images due to surface potential unevenness caused by direct contact between the developing roller and toner regulating member, especially when stored under high-temperature and high-humidity conditions, leading to quality defects in electrophotographic images.
Innovation Solution
Incorporating resin particles with specific toluene absorbency and Martens hardness between the developing roller and toner regulating member to prevent low-molecular-weight components from being adsorbed or causing physical stress, thereby maintaining even electrical resistance and reducing banding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the developing roller and toner regulating member are in direct contact during storage, then the structure is simple and easy to manufacture, but surface potential unevenness occurs causing banding in halftone images
Solution Approach 1:
Resin particles are introduced as an intermediary substance between the developing roller and toner regulating member. These particles prevent direct contact during storage, eliminating surface potential unevenness and banding, while allowing normal toner transfer functionality during operation.
Solution Approach 2:
The electrical resistance of the developing roller surface is controlled by adjusting the resin particle composition and distribution. By changing the resin particle parameters (type, concentration, properties), the surface electrical resistance is maintained within a specific range to prevent memory effects while ensuring proper toner development.
2Adaptability or versatility
If the developing unit is stored under high-temperature and high-humidity conditions, then the storage environment is flexible, but surface potential unevenness increases causing significant banding
Solution Approach 1:
Resin particles are applied in advance to the developing roller surface before storage. These particles act as a protective layer that cushions against the harmful effects of high-temperature and high-humidity storage conditions, preventing surface potential unevenness and memory effects from developing.
Solution Approach 2:
The resin particles serve as a mediator between the developing roller and the harsh storage environment. They prevent direct interaction between moisture and heat with the roller surface, eliminating the cause of surface potential unevenness while allowing flexible storage conditions.
3Reliability
If resin particles with high toluene absorbency are used, then low-molecular-weight components are effectively adsorbed, but surface potential unevenness may occur
Solution Approach 1:
The toluene absorbency of resin particles is precisely controlled within a specific range rather than maximized. This parameter optimization ensures sufficient adsorption of low-molecular-weight components to prevent memory effects, while avoiding excessive absorbency that would cause surface potential unevenness and banding.
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 use of resin particles with controlled toluene absorbency and Martens hardness ensures stable and high-quality electrophotographic images by preventing surface potential unevenness and banding, even under prolonged high-temperature and high-humidity storage conditions.
Implementation Method 1
resin particles with specific toluene absorbency and Martens hardness between the developing roller and toner regulating member to prevent low-molecular-weight components from being adsorbed
Data Source
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AI summary
There is provided a developing unit capable of suppressing to leave a memory on a developing roller (106) even when held under high-temperature and high-humidity conditions for a long period of time before the start of use. The developing unit has a developing roller (106) and a toner regulating member (109) in contact with each other with resin particles (120) therebetween. The resin particles (120) have a toluene absorbency of 20 g or more and 50 g or less per 40 g of the resin particles (120) and a Martens hardness of 1.0 N/mm2 or more and 50.0 N/mm2 or less.