Toner Production via Crystalline Polyester Emulsion Aggregation
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Solution Overview
Problem
Current toner production methods face challenges in achieving both low-temperature fixability and heat-resistant storage properties, with existing technologies either compromising on low-temperature fixability or suffering from high-temperature offset and durability issues during printing.
Innovation Solution
A method of producing toner particles by emulsion aggregation using a binder resin with a block polymer as the main component, where the crystalline polyester portion forms 50-80% of the resin, and a specific heat treatment process is applied to enhance crystallinity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the glass transition point (Tg) of binder resin is reduced to enable low-temperature fixation, then low-temperature fixability is improved, but heat-resistant storage property deteriorates
Solution Approach 1:
The invention changes the fundamental parameter of the binder resin from amorphous to crystalline structure. Crystalline polyester exhibits sharp melting property at a specific melting point while maintaining dimensional stability below that temperature, enabling low-temperature fixation without sacrificing heat-resistant storage properties
Solution Approach 2:
The invention uses composite binder resin comprising crystalline polyester as the main component (50-80 mass%) combined with amorphous resin (20-50 mass%). This composite structure leverages the sharp melting property of crystalline polyester for low-temperature fixation while the amorphous resin provides elasticity and heat-resistant storage stability
2Temperature
If crystalline polyester is used as binder resin to improve low-temperature fixability and heat-resistant storage property, then fixation temperature is reduced and storage stability is improved, but elasticity at high temperature becomes insufficient causing high-temperature offset
Solution Approach 1:
The invention combines crystalline polyester (50-80 mass%) with amorphous resin (20-50 mass%) to create a composite binder resin. The crystalline polyester provides sharp melting for low-temperature fixation and heat-resistant storage stability, while the amorphous resin contributes elasticity at high temperature to prevent offset
Solution Approach 2:
The invention assigns different functional roles to different components: crystalline polyester handles low-temperature fixation and storage stability, while amorphous resin handles high-temperature elasticity. This local functional differentiation resolves the contradiction between low-temperature performance and high-temperature elasticity
3Temperature
If aggregation toner is produced to improve low-temperature fixability, then fixation temperature is reduced, but durability during printing of large number of sheets becomes insufficient causing detachment or cracking
Solution Approach 1:
The invention uses composite binder resin with crystalline polyester (50-80 mass%) and amorphous resin (20-50 mass%) aggregated into toner particles. This composite structure provides both low-temperature fixability and sufficient durability for high-volume printing by combining the sharp melting property with high-temperature elasticity
Solution Approach 2:
The invention optimizes the composition parameters of the binder resin, specifically setting crystalline polyester content at 50-80 mass% and amorphous resin at 20-50 mass%, to achieve the balance between low-temperature fixation and durability required for high-volume printing applications
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 method results in toners that exhibit excellent low-temperature fixability, heat-resistant storage properties, and improved durability during high-volume printing, reducing the risk of offset and cracking.
Implementation Method 1
the crystalline polyester sharply melts at the melting point and sharply reduces its viscosity accompanied thereby
Implementation Method 2
a toner is usually produced by aggregating fine particles of raw materials having an average particle diameter of 1 μm or less
Implementation Method 3
a fusion step of fusing the aggregation particles to form fused particles
Data Source
AI summary
The present invention provides a toner excellent in low-temperature fixability and also excellent in heat-resistant storage property, offset resistance, and durability. In a process for producing a toner containing toner particles by emulsion aggregation, each toner particle includes a binder resin of which a main component is a block polymer having a crystal structure, a colorant, and a release agent; the binder resin includes polyester as a main component; the rate of a portion capable of forming a crystal structure to the binder resin is 50 to 80 mass %; a peak temperature Tp of a maximum endothermic peak attributed to the binder resin is 50 to 80° C. in endothermic amount measurement of the toner with a differential scanning calorimeter (DSC); and fused particles are heated at a heating temperature t (° C.) satisfying Tp′−15.0≦t≦Tp′−5.0 for at least 0.5 hr.