Toner Particle Crystallinity Control via Temperature Holding
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Solution Overview
Problem
Existing toner production methods face challenges in achieving both low-energy fixing and heat-resistant storability while maintaining performance stability during high-temperature storage, as they often result in aggregation, poor image density, and inadequate heat-resistant properties due to the introduction of crystalline resins.
Innovation Solution
A method involving the use of a binder resin with a styrene-acrylic main component and a block polymer containing polyester and vinyl polymer segments, where the temperature of the aqueous medium is controlled between the glass transition point and the onset temperature of the block polymer's endothermic peak to enhance crystallinity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a crystalline resin is added to improve heat-resistant storability, then heat-resistant storability is improved, but the toner aggregates and developing performance deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the degree of crystallinity of the crystalline resin within a specific range (5-60%) and managing the temperature history of the toner. By adjusting these parameters, the toner achieves heat-resistant storability while preventing aggregation and maintaining developing performance.
Solution Approach 2:
The patent uses composite materials by combining a crystalline resin with a binder resin in specific proportions. This composite structure allows the toner to benefit from the heat-resistant properties of the crystalline resin while the binder resin prevents aggregation and maintains developing performance.
2Reliability
If the degree of crystallinity is increased to improve heat-resistant storability, then heat-resistant storability is improved, but low-temperature fixability deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the degree of crystallinity within a specific range (5-60%) and controlling the temperature history. This balanced parameter selection allows the toner to achieve sufficient heat-resistant storability while maintaining adequate low-temperature fixability.
Solution Approach 2:
The patent applies local quality by creating a heterogeneous structure where crystalline resin domains are distributed within the binder resin matrix. This local distribution allows different regions to fulfill different functions: crystalline domains provide heat resistance while the binder matrix ensures low-temperature fixability.
3Object-generated harmful factors
If a dry storage scheme is used to prevent aggregation, then aggregation is reduced, but image density and developing performance worsen
Solution Approach 1:
The patent applies parameter changes by controlling the degree of crystallinity and temperature history to prevent aggregation during storage. This allows the toner to maintain both low aggregation and good developing performance without requiring a wet storage scheme.
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 allows for the production of toner particles with improved low-temperature fixability and heat-resistant storability, minimizing performance changes after high-temperature storage, and achieving a balance between energy efficiency and performance stability.
Implementation Method 1
holding a temperature of the aqueous medium for 60 minutes or more, between a glass transition point TgA (°C.) of the resin particles and an onset temperature TmA (°C.) of an endothermic peak derived from the block polymer in the resin particles, in such a manner that a temperature fluctuation rate is not greater than 0.35° C./minute, and a temperature fluctuation range is not greater than 20° C.
Data Source
AI summary
A method for producing toner particles that contain a binder resin having a styrene-acrylic resin as a main component, a colorant, and a block polymer that has polyester segments and vinyl polymer segments, has a step of producing resin particles in accordance with a suspension polymerization method or a dissolution suspension method, and thereafter, holding the temperature of the aqueous medium in which the resin particles are dispersed, for 60 minutes or more, between a glass transition point TgA (° C.) of the resin particles and an onset temperature TmA (° C.) of an endothermic peak derived from the block polymer in the resin particles, in such a manner that a temperature fluctuation rate not greater than 0.35° C./minute, and a temperature fluctuation range is not greater than 20° C.