Crystalline Polyester Toner for Low-Temperature Fixing and Curl Resistance
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Solution Overview
Problem
Current toners for electrophotography face challenges in achieving low-temperature fixability, image heat resistance, and curl resistance, with existing solutions either compromising on one or more of these performance metrics.
Innovation Solution
A toner formulation with a binder resin containing crystalline polyester, where specific differential scanning calorimetry processes and resin configurations are used to control exothermic and endothermic peak amounts, ensuring optimal compatibility and crystallization rates to balance low-temperature fixability, image heat resistance, and curl resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If crystalline polyester is excessively compatible with binder resin, then low-temperature fixability is improved, but image heat resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compatibility between crystalline polyester and binder resin through specific compositional ratios. The binder resin contains crystalline polyester at 5-20 parts by mass per 100 parts of amorphous resin, and the crystalline polyester has a melting point of 40-80°C. This parameter control achieves low-temperature fixability while maintaining image heat resistance by preventing excessive compatibility.
Solution Approach 2:
The patent uses composite materials by combining crystalline polyester with amorphous resin in a specific ratio range. The binder resin is formulated as a composite system where crystalline polyester (5-20 parts) works synergistically with amorphous resin (100 parts) to achieve both low-temperature fixability and image heat resistance, resolving the contradiction between these two properties.
2Temperature
If crystalline polyester is easily crystallized, then low-temperature fixability is improved, but curl resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the crystallization behavior of crystalline polyester through specific compositional parameters. The melting point of crystalline polyester is controlled at 40-80°C, and the content is limited to 5-20 parts by mass per 100 parts of amorphous resin. This prevents excessive crystallization that would cause curling while maintaining low-temperature fixability.
Solution Approach 2:
The patent applies local quality by creating different functional zones within the binder resin system. The crystalline polyester provides low-temperature fixability in specific regions, while the amorphous resin provides stability and curl resistance in other regions. The spatial distribution and interaction of these components are controlled through the specific compositional ratio.
3Reliability
If toner is used on thick coated paper, then image heat resistance is improved, but compatibility with varied media deteriorates
Solution Approach 1:
The patent applies universality by formulating a binder resin that performs multiple functions simultaneously. The crystalline polyester/amorphous resin composite system provides low-temperature fixability, image heat resistance, and curl resistance all at once, making the toner compatible with various media including thick coated paper without sacrificing adaptability.
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 excellent low-temperature fixability, image heat resistance, and curl resistance by carefully managing the crystallization and compatibility of crystalline polyester with amorphous resin, as evidenced by controlled exothermic and endothermic peak amounts, thereby improving overall performance.
Implementation Method 1
the crystalline polyester is easily crystallized when cooled
Implementation Method 2
an exothermic amount P1 of an exothermic peak derived from the crystalline polyester present at 40° C. or higher and 80° C. or lower observed in the first cooling process
Implementation Method 3
a sharp melting property compared to amorphous polyester
Implementation Method 4
a sum of endothermic amounts of the endothermic peaks present at 40° C. or higher observed in the second temperature rise process
Data Source
AI summary
A toner includes a toner particle containing a binder resin containing a crystalline polyester. In differential scanning calorimetry (DSC), the toner is heated to 180° C. at a rate of 10° C./min, then cooled to 25° C. at a rate of 10° C./min and successively from 25° C. to 15° C. at a rate of 3° C./min, and heated again to 180° C. at a rate of 10° C./min. As a result, an exothermic amount P1 when the toner is cooled from 80° C. to 40° C. is 1.00 J/g or less, an exothermic amount P2 when the toner is cooled from 25° C. to 15° C. is 0.10 J/g or more, and when a sum of endothermic amounts P3 (J/g) when the toner is heated again from 40° C. to 180° C. and a sum of exothermic amounts P4 (J/g) when the toner is cooled from 180° C. to 40° C. satisfies 2.0 ≤ P3-P4 ≤ 10.0.