Toner Viscosity Control for Offset and Fixability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current toners for electrophotographic methods face challenges with low-temperature fixability, offset resistance, and image quality, particularly in achieving high gloss and durability while maintaining performance across a wide fixable temperature range.
Innovation Solution
A toner with specific viscosity characteristics, measured using a flow tester heat-up method, and incorporating a low-molecular weight resin with a glass transition point of 40 to 70°C, produced through suspension polymerization, which enhances low-temperature fixability and offset resistance, and includes a core/shell structure for improved durability and environmental stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a heat roller fixing method or film fixing method is used to achieve quick fixation, then fixation speed is improved, but toner adheres to the heat roller or fixation film surface causing offset and contamination
Solution Approach 1:
The invention changes the physical and chemical parameters of the toner by incorporating a low-molecular weight resin with specific glass transition point (40-70°C) and controlling viscosity characteristics (η100 between 15,000-40,000 Pa·s and AηT between -0.064 and 0). These parameter changes modify the toner's melting and adhesion behavior, allowing it to fix quickly while reducing unwanted adhesion to the heat roller surface.
Solution Approach 2:
The invention uses a composite binder resin system combining a low-molecular weight resin (glass transition point 40-70°C) with other resins to create toner particles with optimized properties. This composite material approach allows the toner to exhibit both good fixability at low temperatures and reduced offset resistance at higher temperatures, resolving the contradiction between fixation speed and offset prevention.
2Temperature
If toner viscosity is reduced to improve low-temperature fixability, then fixation at low temperature is improved, but high-temperature offset resistance and image durability deteriorate
Solution Approach 1:
The invention precisely controls viscosity parameters at different temperatures: η100 (viscosity at 100°C) is maintained between 15,000-40,000 Pa·s and the viscosity change rate AηT is controlled between -0.064 and 0. This dual parameter control allows the toner to have appropriate viscosity for low-temperature fixation while maintaining structural integrity for high-temperature offset resistance and image durability.
Solution Approach 2:
The invention introduces local quality differentiation through the core/shell structure of toner particles, where the shell portion contains the low-molecular weight resin with specific glass transition point. This creates different functional zones: the core provides structural stability for durability, while the shell provides low-temperature fixability, resolving the contradiction between low-temperature fixation and high-temperature resistance.
3Adaptability or versatility
If a wide fixable temperature range is achieved, then adaptability to different fixing conditions is improved, but image quality and gloss may be compromised
Solution Approach 1:
The invention controls the viscosity change rate parameter AηT to be between -0.064 and 0, which means the viscosity decreases slowly or remains relatively stable as temperature increases from 100°C to 110°C. This controlled viscosity behavior allows the toner to adapt to a wide temperature range while maintaining consistent melting and flow characteristics, ensuring high image quality and gloss across different fixing temperatures.
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, high gloss, and wide fixable temperature range, while maintaining high-temperature offset resistance and durability, reducing issues like fogging and peeling.
Implementation Method 1
incorporating a low-molecular weight resin with a glass transition point of 40 to 70°C, produced through suspension polymerization, which enhances low-temperature fixability
Implementation Method 2
when viscosities of the toner particles measured at 100° C. and 110° C. by a flow tester heat-up method are represented by η100 (Pa·s) and η110 (Pa·s)
Data Source
AI summary
A toner is provided which is excellent in low-temperature fixability and offset resistance, has a wide fixing temperature range, provides fixed images with high gloss, and can form toner images having high quality. The toner is composed of toner particles having toner base particles each containing a binder resin and a colorant. When the viscosities of each of the toner particles measured at 100° C. and 110° C. by a flow tester heat-up method are represented by η100 (Pa·s) and η110 (Pa·s), respectively, an average variation in viscosity AηT represented by the following equation (1) satisfies the relationship of 0≧AηT≧−0.064:AηT=(log(η110)−log(η100)/(110−100); and (1)η100 is 15,000 to 40,000 Pa·s.