Polyester Toner Composition for Dispersibility and Low-Temp Fixing
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Solution Overview
Problem
Existing toner particles in electrostatic imaging technologies face challenges in achieving high dispersibility of crystalline polyester resin, maintaining image quality, and ensuring low-temperature fixability, while also addressing issues of image strength and preservability.
Innovation Solution
The use of an amorphous polyester resin with specific monomer compositions and molecular weights, combined with a crystalline polyester resin, enhances dispersibility and improves low-temperature fixability, image glossiness, and image strength by forming a core-shell structure with a suitable binder resin composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If crystalline polyester resin is used in toner particles, then image strength and preservability are improved, but dispersibility of the resin decreases
Solution Approach 1:
The patent employs a composite binder resin system combining amorphous polyester resin and crystalline polyester resin in specific proportions (amorphous: 70-95 mass%, crystalline: 5-30 mass%). This composite approach allows the amorphous resin to provide good dispersibility and flow properties, while the crystalline resin contributes to image strength and preservability, resolving the contradiction between these opposing requirements.
Solution Approach 2:
The patent applies local quality by specifying different molecular weight ranges for the amorphous polyester resin (10,000-50,000) and crystalline polyester resin (5,000-15,000), and by creating a core-shell structure where the resin composition is optimized in different regions of the toner particle to achieve both dispersibility and image strength.
2Temperature
If binder resin composition is optimized for dispersibility, then low-temperature fixability is improved, but image glossiness may deteriorate
Solution Approach 1:
The patent utilizes parameter changes by carefully controlling the molecular weights of the polyester resins (amorphous: 10,000-50,000; crystalline: 5,000-15,000) and their composition ratios (amorphous: 70-95 mass%, crystalline: 5-30 mass%). These parameter optimizations enable the toner to achieve both low-temperature fixability through appropriate melt viscosity and image glossiness through controlled crystallization behavior.
3Strength
If amorphous polyester resin with high molecular weight is used, then image strength is improved, but dispersibility and low-temperature fixability worsen
Solution Approach 1:
The patent applies parameter changes by setting the molecular weight of amorphous polyester resin within a specific range (10,000-50,000) and combining it with crystalline polyester resin of lower molecular weight (5,000-15,000). This balanced molecular weight selection ensures sufficient image strength while maintaining adequate dispersibility and low-temperature fixability, avoiding the extremes of too high or too low molecular weight.
Data Source
AI summary
A toner particle includes a binder resin, a colorant, and a wax. The binder resin includes an amorphous polyester resin and a crystalline polyester resin. The amorphous polyester resin includes, as monomer units, a first monomer having a pendant group, terephthalic acid, and ethylene glycol.