Toner Crystalline Resin Stabilization Low-Temperature Fixability
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Solution Overview
Problem
Toner used in electrophotographic image forming methods face challenges with low-temperature fixability and durability, particularly under high-speed printing conditions, where image streaks and fusion with regulating members occur due to the instability of crystalline resin structures.
Innovation Solution
A toner composition comprising a binder resin of amorphous polyester and a crystalline resin, where the crystalline resin has a specific endothermic peak in a temperature range of 55.0° C. to 95.0° C. and a reversing heat flow ratio of 50.0% or more, with a glass transition temperature difference of 7.0° C. or higher between first and second temperature rises, stabilizing the crystal structure and preventing fusion and streaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a crystalline polyester is added to an amorphous polyester to improve low-temperature fixability, then low-temperature fixability is improved, but image streaks are generated and durability decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the melting point of the crystalline polyester within 60°C to 100°C and the glass transition temperature of the amorphous polyester within 40°C to 80°C. This specific parameter range optimization allows the toner to achieve low-temperature fixability while preventing image streaks and maintaining durability, resolving the technical contradiction between temperature performance and reliability.
Solution Approach 2:
The patent uses a composite material system combining crystalline polyester and amorphous polyester in specific proportions (crystalline polyester: 1-50 parts by mass, amorphous polyester: 50-99 parts by mass). This composite structure leverages the low-temperature melting properties of the crystalline component while the amorphous component provides stability and prevents streaking, effectively resolving the contradiction between fixability and durability.
2Temperature
If the viscosity of toner is reduced to improve low-temperature fixability, then low-temperature fixability is improved, but toner durability decreases under external stress
Solution Approach 1:
The patent utilizes phase transitions by incorporating a crystalline polyester that melts within a specific temperature range (60°C to 100°C). During the fixing process, the crystalline component undergoes melting at low temperatures to achieve good fixability, while the amorphous polyester maintains structural integrity. This phase transition mechanism allows the toner to be soft during fixing but resistant to deformation during storage and handling, resolving the contradiction between low-temperature fixability and durability under external stress.
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 favorable low-temperature fixability and suppresses image streaks even in high-speed machines by stabilizing the crystalline resin structure, enhancing durability and storage stability.
Implementation Method 1
at least one endothermic peak derived from the crystalline resin is present in a temperature range from 55.0° C. to 95.0° C. in a total heat flow
Implementation Method 2
when the toner is measured with a temperature-modulated differential scanning calorimeter
Data Source
AI summary
A toner comprising a toner particle comprising a binder resin and a crystalline resin, wherein the binder resin comprises an amorphous resin, when the toner is measured with a temperature-modulated differential scanning calorimeter, at least one endothermic peak derived from the crystalline resin is present in a temperature range from 55.0° C. to 95.0° C. in a total heat flow; and a ratio of an endothermic quantity of the endothermic peak in a reversing heat flow to an endothermic quantity of the endothermic peak in the total heat flow is 50.0% or more, a glass transition temperature Tg1st obtained in the reversing heat flow in a first temperature rise and a glass transition temperature Tg2nd obtained in a reversing heat flow in a second temperature rise satisfy Tg1st−Tg2nd≥7.0° C.