Domain-Matrix Toner for Low-Temperature Fixing
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Solution Overview
Problem
Conventional electrostatic latent image developing toners face challenges in achieving low-temperature fixability, fixation separability, and high temperature offset resistance, especially on rough papers with large surface irregularities, due to limitations in particle size distribution, binder resin properties, and shell layer formation in core-shell structures.
Innovation Solution
The development of an electrostatic latent image developing toner with a domain-matrix structure, where a styrene-acrylic resin forms the matrix and an amorphous resin, combining vinyl-based and polyester-based polymerized segments, is used to create a toner base particle with a domain diameter of 150 to 1000 nm, optimizing the distribution and affinity of resins for improved fixability and offset resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the glass transition point and molecular weight of the binder resin are lowered to reduce melting temperature and melt viscosity for low-temperature fixability, then low-temperature fixability is improved, but heat-resistant storability and fixation separability are degraded
Solution Approach 1:
The toner particle is divided into a core region containing low glass transition point binder resin for low-temperature fixability and a shell layer containing high glass transition point binder resin for heat-resistant storability and fixation separability. This segmentation allows each region to independently provide its specific function without compromising the other.
Solution Approach 2:
Different regions of the toner particle are assigned different resin compositions with specific glass transition points tailored to their functional requirements. The core region uses resins with lower glass transition points (e.g., -50°C to 0°C) to facilitate low-temperature fixing, while the shell layer uses resins with higher glass transition points (e.g., 50°C to 150°C) to ensure heat-resistant storability and fixation separability.
2Temperature
If a polyester resin is used for the shell layer to achieve low-temperature fixability and heat-resistant storability, then low-temperature fixability is improved, but affinity to styrene-acrylic resin is poor making it difficult to form a thin and uniform shell layer
Solution Approach 1:
A silane coupling agent or titanate coupling agent is introduced as an intermediary substance between the polyester resin and styrene-acrylic resin. This coupling agent improves the interfacial adhesion and compatibility between the two resins, enabling the formation of a thin and uniform shell layer with good affinity despite the inherent poor compatibility between polyester and styrene-acrylic resins.
3Temperature
If the shell layer is formed over the core particle to balance low-temperature fixability and heat-resistant storability, then low-temperature fixability is improved, but fusion between core and shell is poor making shape control difficult
Solution Approach 1:
A silane coupling agent or titanate coupling agent is used as an intermediary to improve the fusion between the core and shell layers. This coupling agent enhances the interfacial adhesion, enabling better shape control and formation of a dense, smooth-toner particle with a uniform shell layer surface.
Solution Approach 2:
The fusion process parameters are optimized, including fusion temperature, fusion time, and fusion pressure, to achieve proper fusion between the core and shell layers while maintaining the desired shape control and surface smoothness of the toner particle.
4Ease of manufacture
If conventional toner manufacturing methods using pulverization process are used to sharpen particle size distribution, then manufacturing simplicity is maintained, but particle size distribution cannot be effectively sharpened
Solution Approach 1:
The manufacturing approach is changed from mechanical pulverization to controlled emulsion polymerization, where particle size distribution is controlled by adjusting polymerization parameters such as monomer feed rate, initiator concentration, and reaction temperature. This allows effective sharpening of particle size distribution while maintaining manufacturing feasibility.
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
This approach enhances low-temperature fixability, fixation separability, and high temperature offset resistance by allowing individual resins to express their intrinsic characteristics, improving the toner's performance on rough papers while maintaining mobility and dischargeability of the mold releasing agent.
Implementation Method 1
In order to lower the fixing temperature of toner, it is necessary to lower the melting temperature and melt viscosity of binder resin
Implementation Method 2
electrostatic latent image developing toner
Data Source
AI summary
An electrostatic latent image developing toner includes a toner base particle (1) which contains at least a binder resin, and has a domain-matrix structure, in which a matrix (2) contains a styrene-acrylic resin, a domain (3) contains an amorphous resin which is formed by combining a vinyl-based polymerized segment and a polyester-based polymerized segment, and the domain (3) containing the amorphous resin and having a diameter of 100 nm or larger has a number-average domain diameter which falls in the range from 150 to 1000 nm.