Electrostatic Toner via Amorphous Polyester and Wax Melt-Kneading
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Solution Overview
Problem
Current toners face challenges in achieving low-temperature fusing ability, high-temperature offset resistance, and heat-resistant storage properties while maintaining high gloss and preventing background fogging, especially in electrophotographic processes.
Innovation Solution
A toner production method involving melt-kneading a mixture with a resin binder composed of an amorphous polyester, specifically polycondensed from an aliphatic diol with 3 or 4 carbon atoms and α,ω-linear alkanediols, and a wax with a melting point between 60°C to 120°C, to enhance low-temperature fusing and heat-resistant storage, and incorporating a crystalline resin for improved gloss and offset resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a styrene-acrylic copolymer is used as charge control agent, then electric charge-donating ability is improved, but dispersion in toner deteriorates due to high molecular weight
Solution Approach 1:
The charge control agent is segmented into multiple functional components: a polyester resin base and surface-grafted styrene-acrylic copolymer. This segmentation allows the hydrophobic polyester core to ensure compatibility and dispersion, while the polar styrene-acrylic graft chains provide charge-donating ability, resolving the contradiction between dispersion and charge function.
Solution Approach 2:
The invention creates a composite charge control agent by grafting styrene-acrylic copolymer chains onto a polyester resin backbone. This composite structure combines the advantages of both materials: the polyester provides good dispersion and compatibility with toner components, while the styrene-acrylic grafts provide excellent charge-donating properties, thus resolving the contradiction between dispersion and charge ability.
2Temperature
If crystalline polyester is used to improve low-temperature fusing ability, then fusing temperature is reduced, but heat-resistant storage property deteriorates
Solution Approach 1:
The invention applies local quality by creating a toner particle with heterogeneous structure: a crystalline polyester core provides low-temperature fusing ability, while an amorphous resin matrix and surface-modified charge control agents provide heat-resistant storage properties. This spatial differentiation of material properties resolves the contradiction between low-temperature fusing and heat-resistant storage.
Solution Approach 2:
The toner uses a composite resin system combining crystalline polyester (for low-temperature fusing) with amorphous resins and modified charge control agents (for heat-resistant storage). This composite material approach allows simultaneous achievement of low fusing temperature and high heat-resistant storage stability by leveraging the complementary properties of different materials.
3Reliability
If amorphous resin is used to improve heat-resistant storage property, then storage stability is improved, but low-temperature fusing ability deteriorates
Solution Approach 1:
The invention implements local quality by assigning different resin types to different functional roles within the toner particle: amorphous resin forms the continuous matrix providing heat-resistant storage stability, while dispersed crystalline polyester domains provide low-temperature fusing capability. This localized functional assignment resolves the contradiction between heat-resistant storage and low-temperature fusing.
4Temperature
If wax content is increased to improve low-temperature fusing ability, then fusing temperature is reduced, but offset resistance deteriorates
Solution Approach 1:
The invention uses parameter changes by precisely controlling the melting point of the wax component (60-120°C) and its content (0.2-13 parts by mass per 100 parts resin binder). This optimized parameter range allows the wax to provide low-temperature fusing ability while the resin matrix maintains sufficient binding strength for offset resistance, resolving the contradiction between low-temperature fusing and offset resistance.
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 with excellent low-temperature fusing ability, heat-resistant storage, high gloss, and reduced background fogging, effectively addressing the limitations of existing toners in electrophotographic applications.
Implementation Method 1
melt-kneading a mixture containing a resin binder and a wax
Implementation Method 2
an amorphous polyester (A) obtained by polycondensing an alcohol component
Implementation Method 3
the wax has a melting point of from 60° to 120°C
Data Source
AI summary
A method for producing a toner for electrostatic image development including the step of melt-kneading a mixture containing a resin binder and a wax, wherein the resin binder contains an amorphous polyester (A) obtained by polycondensing an alcohol component containing an aliphatic diol (a) having 3 or 4 carbon atoms, the aliphatic diol having a hydroxyl group bonded to a secondary carbon atom, and an aliphatic diol (b) containing one or more α,ω-linear alkanediols having 2, 4, 6 or 8 carbon atoms, and a carboxylic acid component. The toner for electrostatic image development can be suitably used in, for example, the development or the like of latent image formed in an electrostatic development method, an electrostatic recording method, an electrostatic printing method, or the like