Carrier Coating for Image Fogging in Two-Component Developer
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Solution Overview
Problem
In electrographic image forming apparatuses, the performance of carriers deteriorates over time due to toner components attaching to the carrier surface, leading to decreased toner charge and image quality issues such as fogging, especially when using two-component developers with small toner particle diameters.
Innovation Solution
The implementation of a trickle developing system that supplies a mixture of toner and carrier with inorganic fine particles attached to both the toner and carrier, maintaining a specific ratio of inorganic fine particles to carrier mass, which inhibits the transfer of external additives to the carrier and maintains consistent charge application performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two-component developer with small toner particle diameters is used, then image quality is improved, but carrier performance deteriorates faster due to external additive transfer
Solution Approach 1:
The invention changes the physical and chemical parameters of the carrier by coating its surface with a specific layer structure (resin layer containing charge controlling agent and inorganic fine particles). This modifies the carrier's interaction with toner and external additives, preventing performance deterioration while maintaining high image quality with small toner particles.
Solution Approach 2:
The carrier is constructed as a composite material with a core and a surface coating layer. The coating layer contains resin, charge controlling agent, and inorganic fine particles, creating a multi-component structure that combines the magnetic properties of the core with the protective and charge-controlling functions of the coating, thereby stabilizing carrier performance.
2Productivity
If image formation is performed over a long period of time, then productivity is improved, but toner charge decreases due to carrier performance deterioration
Solution Approach 1:
The carrier surface is preliminarily prepared with a coating layer containing charge controlling agent and inorganic fine particles before use. This preliminary action ensures that the carrier maintains its charge transfer capability throughout extended operation, preventing toner charge decrease even during long-period image formation.
Solution Approach 2:
Instead of replacing the entire carrier after performance deterioration, the invention uses a carrier with a designed surface layer that resists degradation. The inorganic fine particles and resin coating act as a sustainable protective structure that maintains functionality over extended periods, effectively making the carrier long-lasting rather than short-living.
3Productivity
If external additives are transferred to carrier surface, then charge application performance deteriorates, but image formation continues
Solution Approach 1:
The invention converts the potential harm of external additive transfer into a beneficial structure. The coating layer on the carrier is specifically designed to incorporate inorganic fine particles that attract and hold external additives, preventing them from migrating to the toner surface. This transforms what would be a harmful contamination process into a controlled containment mechanism that maintains charge application 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 ensures minimal deterioration of the toner charge and prevents image fogging, allowing for the formation of high-quality images over an extended period by maintaining consistent charge application performance and reducing carrier performance differences.
Implementation Method 1
the carrier lies in the shape of brushes on the development roller. Since the toner is attached on the carrier, a magnetic brush made from the two-component developer is formed. By causing the magnetic brush to come in contact with or be in close proximity to the photoreceptor, the toner is supplied to the surface of the photoreceptor
Implementation Method 2
when the ratio of mass of inorganic fine particles attached to the carrier contained in the two-component developer to mass of the carrier contained in the two-component developer is A
Data Source
AI summary
An image forming apparatus includes a developer tank which houses two-component developer containing toner and carrier, and a supply unit which supplies the developer tank with supply developer containing toner and carrier, wherein, when the ratio of mass of inorganic fine particles attached to the carrier contained in the two-component developer to mass of the carrier contained in the two-component developer is A, and when the ratio of mass of inorganic fine particles attached to the carrier contained in the supply developer to mass of the carrier contained in the supply developer is B, the following Formula (1) is satisfied:0.7<B/A<0.96 (1).