Composite Polyester Toner for Low-Temperature Fixing
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Solution Overview
Problem
Current toner technologies face challenges in achieving high-quality images with smaller particle diameters, energy efficiency, and preventing issues like toner blocking and image defects such as white stripes and trickle-down, while maintaining low temperature fixability and powder flowability.
Innovation Solution
A toner formulation comprising an amorphous polyester resin, a crystalline polyester resin, and a releasing agent, with specific weight percentages and surface ratios, exhibiting multiple endothermic peaks in differential scanning calorimetry, which enhances compatibility and dispersibility, thereby improving low temperature fixability, powder flowability, and releasability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the glass transition temperature of binder resin is lowered to reduce fixing temperature, then low temperature fixability is improved, but toner blocking and image defects occur
Solution Approach 1:
The invention uses a composite binder resin system combining amorphous polyester resin and crystalline polyester resin in specific proportions. The amorphous resin (50-90 wt%) provides low glass transition temperature for low-temperature fixing, while the crystalline resin (10-50 wt%) with melting point 60-90°C prevents toner blocking and maintains structural integrity, resolving the contradiction between low fixing temperature and blocking prevention.
Solution Approach 2:
The invention precisely controls the glass transition temperature of the amorphous polyester resin within 40-70°C and the melting point of the crystalline polyester resin within 60-90°C. By optimizing these thermal parameters and their ratio, the toner achieves both low-temperature fixability and resistance to blocking, transforming the thermal properties to satisfy multiple conflicting requirements.
2Manufacturing precision
If toner particle diameter is reduced to achieve higher definition images, then image quality is improved, but powder flowability deteriorates
Solution Approach 1:
The invention optimizes toner particle size within 3-8 μm and controls the glass transition temperature of the binder resin between 40-70°C. This parameter optimization ensures that smaller particles maintain adequate flowability while achieving high definition imaging, as the controlled thermal properties prevent particle aggregation and maintain dispersibility.
Solution Approach 2:
The dual-resin binder system creates a composite structure that balances adhesion and flow characteristics. The amorphous resin provides flexibility and low-temperature processing for fine particles, while the crystalline resin provides structural support, enabling small particle size without sacrificing powder flowability.
3Reliability
If releasing agent amount is increased to improve releasability, then offset resistance is improved, but toner powder flowability deteriorates
Solution Approach 1:
The invention precisely controls the releasing agent content at 3-15 wt% and optimizes its molecular structure (using compounds with 18-36 carbon atoms). This parameter control ensures sufficient offset resistance while preventing excessive lubrication that would harm powder flowability, achieving a balanced performance.
Solution Approach 2:
The releasing agent is strategically positioned primarily at the toner surface through controlled incorporation into the binder resin system. This localized distribution provides offset resistance at the image-transfer interface while maintaining bulk powder flowability, as the releasing agent concentrates where it is most needed for prevention of offsetting.
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 formulation achieves improved low temperature fixability, reduced toner exposure, and enhanced powder flowability, leading to higher image quality and reduced energy consumption while minimizing defects like toner blocking and image defects.
Implementation Method 1
the toner showing at least one endothermic peak in each of a temperature range from about 45 to about 60° C., a temperature range from about 65 to about 80° C., and a temperature range from about 85 to about 100° C. in a temperature-rise process of differential scanning calorimetry of the toner
Data Source
AI summary
A toner for developing an electrostatic charge image includes: an amorphous polyester resin; a crystalline polyester resin; and a releasing agent, an amount of the releasing agent in the toner being from 5 to 15% by weight; an amount of the releasing agent present at a surface of the toner being from 10 to 35% by weight; and the toner showing at least one endothermic peak in each of a temperature range from 45 to 60° C., a temperature range from 65 to 80° C., and a temperature range from 85 to 100° C. in a temperature-rise process of differential scanning calorimetry of the toner.