Porous Ferrite Carrier for Developing Agent
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Solution Overview
Problem
In color image forming apparatuses, increased agitation stress on developing agents leads to toner deterioration, while existing solutions like lowering carrier specific gravity or adding conductive particles result in issues like carrier deformation, fluidity reduction, or image staining.
Innovation Solution
A two-component developing agent comprising toner with a binding resin and carrier particles with a porous ferrite core and a resin covering layer containing ferrite particles, where the ferrite particles have an average diameter of 0.1 to 1.0 μm, reducing agitation stress and enhancing developability while maintaining fluidity and preventing image staining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the specific gravity of the carrier is lowered to reduce agitation stress on toner, then the agitation stress is reduced, but the carrier particles become easily crushed or deformed when receiving impact
Solution Approach 1:
The carrier is constructed as a composite material with a porous ferrite core particle and a resin covering layer containing ferrite particles. This composite structure reduces the specific gravity to lower agitation stress while the resin covering layer provides mechanical strength to prevent crushing or deformation during impact.
2Reliability
If carbon black is put in the resin covering layer to raise electric resistance and enhance developability, then the developability is improved, but resin powder stained with carbon black stains images when the covering layer is abraded or exfoliated
Solution Approach 1:
Instead of using carbon black which causes staining when the covering layer deteriorates, ferrite particles are used. Ferrite particles provide the necessary electric resistance enhancement for improved developability while not causing image staining even when the resin covering layer is abraded or exfoliated, as ferrite particles do not stain images like carbon black does.
3Reliability
If magnetite is put in the resin covering layer to decrease white splotches, then the developability is improved, but the high residual magnetization of magnetite decreases the fluidity of the carrier
Solution Approach 1:
The patent changes the material parameter from magnetite to ferrite particles. Ferrite particles have lower residual magnetization compared to magnetite, which maintains the necessary magnetic properties for developability and reduces white splotches while preserving carrier fluidity. The particle size parameter is also controlled within 0.1 to 1.0 μm to optimize both developability and fluidity.
4Ease of operation
If the carrier structure is modified to improve fluidity, then the fluidity is enhanced, but the transfer rate decreases and edge effects increase
Solution Approach 1:
The composite structure with porous ferrite core and resin covering layer containing ferrite particles creates an optimal balance. The resin covering layer with controlled ferrite particle content (0.1 to 1.0 μm) provides sufficient magnetic properties for high transfer rate and reduced edge effects while maintaining good fluidity through the porous core structure and appropriate resin composition.
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 reduces agitation stress on toner, enhances transfer rates, minimizes edge effects, and prevents image density unevenness and staining, resulting in high-quality images with improved carrier durability and fluidity.
Implementation Method 1
it has been commonly performed to put carbon black in a resin covering layer of a carrier to raise an electric resistance of the carrier and enhance developability
Implementation Method 2
a carrier including carrier particles, each of which includes a porous ferrite core particle and a resin covering layer which covers the surface of the porous ferrite core particle; the resin covering layer includes ferrite particles
Data Source
AI summary
A two-component developing agent includes toner and a carrier including carrier particles. The toner includes a binding resin. The carrier particle includes a porous ferrite core particle and a resin covering layer. The resin covering layer covers the porous ferrite core particle. The resin covering layer includes ferrite particles. An average particle diameter of the ferrite particles ranges from 0.1 to 1.0 μm.