Magnetic Carrier Resin Layer for Toner Charge Stability
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Solution Overview
Problem
Existing electrophotographic image forming methods face challenges in maintaining high-quality image density and stability across varying environmental conditions, particularly at low-temperature and low-humidity environments, where toner becomes excessively charged, leading to decreased image density over time.
Innovation Solution
A magnetic carrier with a resin covering layer containing a vinyl-based copolymer and a specific compound, where the resin covering layer includes a compound represented by Formula (1) with a chain alkyl group of 6 to 12 carbon atoms, and a methoxy or ethoxy group, which regulates charge relaxation characteristics, and a vinyl-based copolymer with a (meth)acrylate having an alicyclic hydrocarbon group to enhance charging stability and reduce image density changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional magnetic carriers are used in low-temperature and low-humidity environments, then image forming is possible, but toner becomes excessively charged leading to decreased image density over time
Solution Approach 1:
The patent modifies the surface properties of the magnetic carrier by controlling the glass transition temperature (Tg) of the cover layer resin and adjusting the carrier charge relaxation characteristics. By setting Tg within 80-120°C and controlling charge relaxation time constant, the carrier can adapt to low-temperature environments while preventing excessive toner charging, thus maintaining stable image density across varying environmental conditions
Solution Approach 2:
The patent uses a composite cover layer structure combining specific resin materials (polyester resin, acrylic resin, or vinyl resin) with controlled molecular weight and glass transition temperature. This composite material design provides both mechanical stability and controlled charge relaxation properties, preventing toner overcharging in low-temperature environments while maintaining image quality
2Productivity
If high-speed copying is required, then productivity increases, but maintaining stable image quality across environmental changes becomes more difficult
Solution Approach 1:
The patent introduces dynamic adaptability to the magnetic carrier by controlling charge relaxation characteristics. The carrier can dynamically adjust its charge state based on environmental conditions and usage intensity, allowing high-speed operation while maintaining stable image quality. The charge relaxation time constant is controlled to enable rapid charge dissipation during high-speed copying while preventing overcharging during idle periods
3Duration of action of stationary object
If conventional carriers are used for long-term use, then extended operation is possible, but image quality deteriorates under varying environmental conditions
Solution Approach 1:
The patent implements preventive measures by designing the cover layer with specific glass transition temperature and charge relaxation characteristics before environmental stress occurs. The controlled Tg (80-120°C) and charge relaxation properties act as a buffer against temperature and humidity variations, preventing image quality deterioration before it happens during long-term use across different environmental conditions
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 stabilizes high-quality image output across different environmental conditions by regulating charge relaxation characteristics and improving adhesion, resulting in consistent image density and reduced changes in image quality over time.
Implementation Method 1
the resin covering layer contains a vinyl-based copolymer and a compound represented by Formula (1)... which regulates charge relaxation characteristics
Implementation Method 2
the resulting mixture is subjected to triboelectric charging to provide an appropriate amount of a positive or negative charge to the toner
Implementation Method 3
a magnetic carrier core particle having an amino group on a surface thereof
Data Source
AI summary
A magnetic carrier includes a magnetic carrier particle including a magnetic carrier core particle having an amino group on a surface thereof and a resin covering layer disposed on the surface of the magnetic carrier core particle, in which the resin covering layer contains a vinyl-based copolymer and a trialkoxyalkylsilane.