Toner Composition with Modified Layered Mineral for Low-Temperature Fixing
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Solution Overview
Problem
Conventional toner production methods, such as the kneading-pulverization method, face challenges in achieving small particle diameter, irregular shape, broad particle diameter distribution, high energy consumption for fixing, and poor low-temperature fixability, while methods like polymerization improve fixability but may not satisfy high levels of low-temperature fixability required in recent years.
Innovation Solution
A toner composition including a binder resin, a release agent, and a modified layered inorganic mineral, with specific glass transition temperatures and molecular weight distributions, is developed to achieve low-temperature fixability and heat-resistant storage stability, while minimizing additive roughness and filming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the kneading-pulverization method is used to produce toner, then the production process is simple, but the particle diameter cannot be reduced sufficiently and the particle size distribution is broad
Solution Approach 1:
The patent changes the fundamental production method from mechanical kneading-pulverization to chemical polymerization, transforming the process parameters from mechanical force and temperature to chemical reaction conditions (monomer composition, initiator type, reaction temperature, and time), enabling precise control of particle diameter and size distribution
Solution Approach 2:
The patent utilizes phase separation during polymerization to form the toner particles, where the resin phase and release agent phase separate into distinct domains, creating the desired particle morphology and size distribution through controlled phase transition rather than mechanical pulverization
2Temperature
If wax is added to improve fixability, then low-temperature fixability is improved, but the toner cracks during pulverization and adheres to carriers and photoconductors
Solution Approach 1:
Instead of adding wax to an already-formed toner (which causes cracking during pulverization), the patent inverts the approach by incorporating the release agent into the toner base during polymerization, creating a homogeneous structure where the release agent is uniformly distributed within the resin matrix, eliminating the cracking problem while maintaining low-temperature fixability
Solution Approach 2:
The patent creates a composite toner structure where the resin and release agent form a sea-island phase separation structure with the release agent dispersed as islands within the resin sea, combining the adhesive properties of the resin with the release properties of the wax in a stable composite material
3Temperature
If conventional toner formulations are used, then general performance is maintained, but low-temperature fixability does not meet high-level requirements
Solution Approach 1:
The patent precisely controls the glass transition temperature of the binder resin within a specific range (−50°C to 100°C) and the melting point of the release agent (60°C to 90°C), optimizing these thermal parameters to achieve high-level low-temperature fixability while maintaining stability
Solution Approach 2:
The patent creates local quality differences within the toner particle through phase separation, where the resin phase provides structural integrity and the release agent phase provides low-temperature melting and release properties, with each phase optimized for its specific function
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 achieves excellent low-temperature fixability, heat-resistant storage stability, and improved drum cleanability, reducing image roughness and additive filming, making it suitable for high-speed printing under varying environmental conditions.
Implementation Method 1
The component insoluble in THF has two glass transition temperatures of Tga1st and Tgb1st at a first temperature rise in differential scanning calorimetry (DSC). The Tga1st is −40° C. or more and 10° C. or less, and the Tgb1st is 45° C. or more and 65° C. or less.
Implementation Method 2
The modified layered inorganic mineral is obtained by modifying, with an organic ion, at least part of ions between layers in a layered inorganic mineral.
Implementation Method 3
A liberation ratio A of silica from the toner, represented by % by mass, satisfies a relation (1) below: 0.5≤A≤1.0
Data Source
AI summary
A toner includes toner base and an external additive containing silica. The toner base includes binder resin, colorant, release agent, and modified layered inorganic mineral that is obtained by modifying, with an organic ion, part of ions between layers in layered inorganic mineral. An amount of the modified layered inorganic mineral is 0.1 parts by mass or more and less than 1.4 parts by mass relative to 100 parts by mass of the toner. Liberation ratio A (% by mass) of silica from the toner satisfies relation (1): 0.5≤A≤1.0. The binder resin includes a component insoluble in THF and a component soluble in THF. The component insoluble in THF has two glass transition temperatures of Tga1st and Tgb1st at first temperature rise in DSC. The Tga1st is −40° C. or more and 10° C. or less. The Tgb1st is 45° C. or more and 65° C. or less.