Low Specific Gravity Carrier with Controlled Siloxane Content
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Solution Overview
Problem
Electrophotographic developers with carriers composed of magnetic and non-magnetic components experience fluctuations in charge amount due to environmental changes and aging, leading to reliability and longevity issues.
Innovation Solution
A carrier with a magnetic component of porous ferrite particles and a non-magnetic component comprising a siloxane compound, cured without volatile organic solvents, is developed, with controlled water and cyclic siloxane content to maintain low specific gravity and stable charge properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a core material with hollow or porous structure is used to reduce specific gravity, then the weight of the carrier is reduced, but the strength of the core material becomes insufficient
Solution Approach 1:
The core material is constructed as a composite consisting of magnetic powder particles dispersed in a resin matrix. This composite structure allows the resin to provide mechanical strength and structural integrity while the magnetic powder provides the necessary magnetic properties, thereby achieving both reduced weight and sufficient strength simultaneously
Solution Approach 2:
The core material utilizes a porous structure where magnetic powder particles are distributed within the resin matrix. This porous configuration reduces the overall density and specific gravity of the carrier while maintaining adequate structural strength through the resin framework
2Weight of moving object
If magnetic powder is dispersed in resin to create low specific gravity carrier, then the weight is reduced, but the magnetic properties and electrical properties become insufficient
Solution Approach 1:
The invention optimizes the composition parameters by controlling the ratio of magnetic powder to resin, the particle size distribution of magnetic powder, and the density of the dispersed phase. These parameter adjustments ensure that the carrier maintains adequate magnetic properties for toner attraction and electrical properties for charge control, while achieving reduced specific gravity
Solution Approach 2:
The carrier employs a composite material system where magnetic powder particles are dispersed in a resin matrix. This composite structure allows the magnetic powder to provide necessary magnetic properties while the resin provides structural support and contributes to electrical properties, achieving a balance between weight reduction and property maintenance
3Ease of manufacture
If volatile organic solvents are used in manufacturing process, then the resin coating process is facilitated, but the volatile organic compound content in carrier increases
Solution Approach 1:
The invention changes the physical state parameter of the resin from solution form (requiring volatile organic solvents) to powder or melt form. This parameter change eliminates the need for volatile organic solvents in the coating process, thereby preventing VOC emissions while still enabling effective resin coating on the core material through alternative application methods
Solution Approach 2:
The invention replaces persistent harmful substances (volatile organic solvents that remain in the carrier) with alternative materials or methods that do not leave harmful residues. By using powder resin or melt resin instead of solvent-based resin solutions, the process eliminates the need for solvents that would otherwise remain as contaminants in the final carrier product
4Weight of moving object
If the carrier structure is modified to reduce specific gravity, then the stress on carrier during stirring is reduced, but the adhesion of toner on carrier becomes insufficient
Solution Approach 1:
The invention applies local quality enhancement by adding a surface coating layer on the carrier particles. This surface layer has different properties from the core material, specifically providing enhanced surface characteristics that improve toner adhesion. The core maintains its low specific gravity structure while the surface layer locally provides the necessary adhesion properties for reliable toner attachment
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 results in a carrier with reduced environmental fluctuation and charge stability over time, enhancing the reliability and longevity of the electrophotographic developer.
Implementation Method 1
a non-magnetic component finished by curing a non-magnetic component composition without volatile organic solvents
Implementation Method 2
the functions of the carrier is to triboelectrically charge the toner in mixing and stirring the carrier with the toner
Implementation Method 3
a core material composed of a magnetic component and a non-magnetic component
Data Source
AI summary
An object of the present invention is to provide a carrier low in specific gravity and less in both environmental fluctuation and change of the charge amount after aging, an electrophotographic developer using the carrier, and a method of manufacturing the carrier. To achieve the object, the carrier is manufactured by coating a core material composed of a magnetic component and a non-magnetic component with a resin, and the carrier is characterized in that water content is 200 ppm or less and cyclic siloxane content is 100 ppb or less. Further, an electrophotographic developer containing the carrier is provided.