Positively Chargeable Toner with Optimized Amine Value
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Solution Overview
Problem
Existing toners for electrostatic charge image development in electrophotography face challenges in achieving optimal positive charging characteristics and stability, particularly under high-temperature and high-humidity conditions, while also minimizing fogging and hygroscopicity.
Innovation Solution
A positively chargeable toner is developed with toner mother particles containing a binder resin having ethylenically unsaturated bonds, where the amine value and weight average molecular weight of components extracted with ion exchanged water after mixing with methyl ethyl ketone are specifically optimized, incorporating a polymer compound with amino groups to enhance charging properties and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional toners are used, then the basic electrophotography function is achieved, but the positive charging characteristics and stability under high-temperature and high-humidity conditions are insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters of the binder resin by specifying precise ranges for amine value (600-1,250) and weight average molecular weight (1,000-200,000). These parameter changes enable the toner to achieve stable positive charging characteristics while maintaining performance across varying environmental conditions, directly resolving the contradiction between charging stability and environmental adaptability.
Solution Approach 2:
The patent employs a composite binder resin system combining resin with ethylenically unsaturated bonds and resin with amino groups. This composite material approach creates synergistic effects where the unsaturated bond provides structural stability and the amino group enhances charging characteristics, achieving both reliable charging performance and environmental adaptability simultaneously.
2Quantity of substance
If toner composition is optimized for charging properties, then positive charging amount increases, but fogging and hygroscopicity may increase
Solution Approach 1:
The patent precisely controls the amine value parameter within the range of 600-1,250 and weight average molecular weight within 1,000-200,000. This optimized parameter range maximizes the positive charging amount while preventing excessive fogging. The specific molecular weight range ensures adequate charging capacity without the hygroscopicity and fogging issues associated with higher amine values.
Solution Approach 2:
The patent introduces amino groups at specific locations within the binder resin structure rather than uniformly throughout. This localized modification approach enhances charging properties at the critical surface regions while maintaining overall resin stability and preventing excessive hygroscopicity and fogging throughout the toner particle.
3Reliability
If binder resin with amino groups is added to enhance charging properties, then charging stability improves, but hygroscopicity increases
Solution Approach 1:
The patent carefully controls the weight average molecular weight parameter within the range of 1,000-200,000. This molecular weight optimization is crucial because it provides sufficient amino group content for stable charging while limiting the overall resin quantity that could contribute to hygroscopicity. The parameter balance achieves charging stability without excessive hygroscopicity.
Solution Approach 2:
The patent combines resin with ethylenically unsaturated bonds and resin with amino groups in a composite system. The unsaturated bond resin component provides structural integrity and reduces hygroscopicity, while the amino group resin provides charging stability. This composite approach allows the benefits of amino groups without their full hygroscopicity penalty.
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 a larger positive charging amount, improved stability, and reduced fogging, while maintaining low hygroscopicity, even in harsh environments, thereby enhancing the performance of electrostatic charge image development.
Implementation Method 1
binder resin having an ethylenically unsaturated bond
Implementation Method 2
a component extracted with a water phase by the addition of ion exchanged water after mixing the toner with methyl ethyl ketone
Data Source
AI summary
There is provided a positively chargeable toner including toner mother particles containing a binder resin having an ethylenically unsaturated bond, wherein the amine value of a component extracted with a water phase by the addition of ion exchanged water after mixing the toner with methyl ethyl ketone is from 600 to 1,250 and the weight average molecular weight of the component extracted with the water phase is from 1,000 to 200,000.