Toner with Crystalline Polyester Core and Oxazoline Shell
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Solution Overview
Problem
Conventional toners face challenges in achieving both low-temperature fixability and hot offset resistance, with existing formulations often compromising on viscosity and elasticity, leading to issues with image formation and preservation.
Innovation Solution
A toner composition featuring a toner core with crystalline and crosslinked non-crystalline polyester resins, coated with a shell layer containing an oxazoline group, which provides a balance of viscosity and elasticity across a wide temperature range, ensuring excellent fixability and heat-resistant preservability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional toner formulations are used, then manufacturing is simpler, but the toner cannot achieve both low-temperature fixability and hot offset resistance simultaneously
Solution Approach 1:
The toner uses a composite resin system combining crystalline polyester resin (for hot offset resistance) and amorphous polyester resin (for low-temperature fixability). This composite material approach allows simultaneous achievement of both hot offset resistance and low-temperature fixability by leveraging the complementary properties of different resin components.
Solution Approach 2:
The invention optimizes specific parameter ranges: glass transition point (Tg) of 50-90°C, melting point (Tm) of 60-80°C, and loss tangent values at different temperatures. By precisely controlling these parameters within specified ranges, the toner achieves both low-temperature fixability (high loss tangent at low T) and hot offset resistance (low loss tangent at high T).
2Reliability
If the toner has high viscosity at low temperatures for good fixability, then fixability is improved, but hot offset resistance deteriorates
Solution Approach 1:
The toner exhibits dynamic viscosity changes with temperature. At low temperatures (fixing temperature), the loss tangent is high (≥1.00) providing high viscosity for good fixability. At high temperatures (storage temperature), the loss tangent becomes low (≤0.50) providing low viscosity for hot offset resistance. This dynamic response to temperature changes resolves the contradiction between fixability and hot offset resistance.
Solution Approach 2:
The crystalline polyester resin component undergoes phase transition at its melting point (60-80°C). Below Tm, the resin is crystalline and provides structural integrity for hot offset resistance. Above Tm, the resin melts and becomes amorphous, contributing to low-temperature fixability. This phase transition mechanism enables the toner to exhibit different rheological properties at different temperatures.
3Object-affected harmful factors
If the toner has high elasticity at high temperatures for hot offset resistance, then hot offset resistance is improved, but low-temperature fixability deteriorates
Solution Approach 1:
The invention specifies precise parameter ranges to balance hot offset resistance and low-temperature fixability: glass transition point Tg of 50-90°C (optimizing the transition temperature), melting point Tm of 60-80°C (optimizing the crystalline-to-amorphous transition), and controlled loss tangent values (≥1.00 at low T, ≤0.50 at high T). These parameter optimizations ensure both hot offset resistance and low-temperature fixability are achieved simultaneously.
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 exhibits high viscosity at low temperatures for effective fixability and high elasticity at high temperatures to prevent hot offset, maintaining excellent heat-resistant preservability and image quality over a wide temperature range.
Implementation Method 1
an endothermic energy amount due to melting of portions in which the crystalline polyester resin is crystallized is at least 0.0 mJ/mg and no greater than 1.0 mJ/mg
Implementation Method 2
A loss tangent of the toner at 60° C. is at least 1.00 and no greater than 4.00. A loss tangent of the toner at 100° C. is at least 1.00 and no greater than 4.00. A loss tangent of the toner at 160° C. is at least 0.01 and no greater than 0.50. A loss tangent of the toner at 200° C. is at least 0.01 and no greater than 0.50
Implementation Method 3
The shell layer contains a resin that has a repeating unit including an oxazoline group
Data Source
AI summary
A toner includes a plurality of toner particles each including a toner core and a shell layer covering a surface of the toner core. The toner core contains a crystalline polyester resin, a crosslinked non-crystalline polyester resin, and an uncrosslinked non-crystalline polyester resin. An endothermic energy amount ΔHPES is at least 0.0 mJ/mg and no greater than 1.0 mJ/mg. The shell layer contains a resin that has a repeating unit including an oxazoline group. The toner has a glass transition point of at least 10° C. and no greater than 40° C. Loss tangents tan δ60 and tan δ100 of the toner are each at least 1.00 and no greater than 4.00. Loss tangents tan δ160 and tan δ200 of the toner are each at least 0.01 and no greater than 0.50.