Toner with Al-Si Composite Additives for Low-Temp Fixing
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Solution Overview
Problem
Toner for electrostatic charge image development faces challenges in maintaining low-temperature fixability and stability across various printing environments, including high-temperature and high-humidity, low-temperature and low-humidity, and low printing modes, due to issues with image density, fogging, and embedding of external additives.
Innovation Solution
A toner formulation incorporating a binder resin with both crystalline and amorphous polyester resins, along with Al—Si composite oxide particles as external additives, where the Si element content ranges from 50 to 90 mass % and the Si element ratio on the surface is controlled between 3 to 35 at %, to enhance fluidity and prevent excessive charging and embedding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If silica particles are externally added to improve fluidity, then fluidity is improved, but image density decreases in low-temperature and low-humidity environment
Solution Approach 1:
The patent uses composite oxide particles containing both Al and Si elements instead of pure silica particles. The composite structure combines the fluidity-enhancing properties of SiO2 with the charge stability of Al2O3, creating a material that provides both good fluidity and stable image density across different environmental conditions.
Solution Approach 2:
The patent optimizes the Si element ratio on the particle surface to be 3-35 at%, which balances the competing requirements. This parameter control ensures sufficient fluidity while preventing excessive negative charging that would cause image density decrease in low-temperature and low-humidity environments.
2Speed
If alumina particles are externally added to improve fluidity, then fluidity is improved, but external additive embedding occurs in low printing mode
Solution Approach 1:
The composite oxide particles with both Al and Si elements create a surface structure that reduces embedding. The SiO2 component provides a smoother surface that prevents the external additive from being embedded into the toner particle during low printing mode operation, while Al2O3 maintains charge stability.
Solution Approach 2:
The patent creates a specific surface composition on the external additive particles with Si element ratio of 3-35 at% on the surface. This local compositional control at the particle surface provides optimal properties for preventing embedding while maintaining fluidity, distinguishing it from the bulk composition.
3Speed
If titania particles are externally added to improve fluidity, then fluidity is improved, but fogging occurs on non-printed portion in high-temperature and high-humidity environment
Solution Approach 1:
The patent replaces pure titania particles with composite oxide particles containing Al and Si elements. This substitution eliminates the fogging problem associated with TiO2 in high-temperature and high-humidity environments while maintaining good fluidity through the SiO2 component and optimized surface composition.
4Temperature
If crystalline polyester resin is used to lower melt viscosity, then low-temperature fixability is improved, but electric resistance decreases under high-temperature and high-humidity conditions
Solution Approach 1:
The patent combines crystalline polyester resin with amorphous polyester resin in a composite binder system. The crystalline component provides low-temperature fixability through quick melting, while the amorphous component maintains higher electric resistance under high-temperature and high-humidity conditions due to its highly polar nature and high internal cohesion.
Solution Approach 2:
The patent optimizes the composition ratio between crystalline and amorphous polyester resins to balance competing properties. This parameter control allows the toner to achieve both low melting point for easy fixing and sufficient electric resistance for stable charging in harsh environments.
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 toner achieves stable high-quality image formation with improved low-temperature fixability, suppressed image density decreases, and reduced fogging across diverse environmental conditions, ensuring consistent performance in different printing modes.
Implementation Method 1
Crystalline polyester resins, which have a property of melting quickly at a temperature equal to or higher than the melting point
Implementation Method 2
amorphous polyester resins are highly polar and have high internal cohesion
Implementation Method 3
a Si element ratio on surfaces of the Al—Si composite oxide particles is in the range of 3 to 35 at %
Data Source
AI summary
A toner for electrostatic charge image development is a toner for electrostatic charge image development including toner particles containing a binder resin and an external additive, wherein the binder resin contains a crystalline polyester resin and an amorphous polyester resin, the external additive includes Al—Si composite oxide particles, and a Si element content of the Al—Si composite oxide particles is in the range of 50 to 90 mass % and a Si element ratio on surfaces of the Al—Si composite oxide particles is in the range of 3 to 35 at %.