Toner Binder Resin Molecular Architecture for Fixing and Offset
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Solution Overview
Problem
Conventional toners face a trade-off between low temperature fixability, preservation stability, and stress resistance, with existing methods either compromising high temperature preservability or hot offset resistance, leading to issues like abnormal images and contamination of image forming members.
Innovation Solution
A toner with a binder resin that includes a rigid and linear low molecular weight component, ensuring compatibility with high molecular weight components and maintaining low melt viscosity, is developed, with specific molecular weight and inertia square radius ratios that enhance fixability, stability, and stress resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a low-temperature fusible toner is used, then low temperature fixability is improved, but preservation stability and stress resistance deteriorate
Solution Approach 1:
The invention changes the molecular weight distribution parameters of the binder resin, specifically controlling the weight average molecular weight to 5,000-50,000 and the number average molecular weight to 2,000-20,000, with a polydispersity index of 1.2-2.0. This parameter optimization allows the toner to maintain low melting point for low-temperature fixing while preserving stability and stress resistance through the controlled molecular architecture.
Solution Approach 2:
The invention uses a composite binder resin system combining polyester resin and polyurethane resin in specific ratios (polyester resin 30-70 wt%, polyurethane resin 30-70 wt%). This composite structure enables the toner to achieve both low-temperature fusibility from the polyester component and enhanced preservation stability and stress resistance from the polyurethane component with controlled molecular weight distribution.
2Temperature
If the molecular weight of binder resin is reduced to improve low temperature fixability, then fixing temperature is lowered, but hot offset resistance deteriorates
Solution Approach 1:
The invention optimizes the molecular weight parameters by setting weight average molecular weight to 5,000-50,000 and number average molecular weight to 2,000-20,000, with controlled polydispersity index of 1.2-2.0. This specific molecular weight range provides low enough melting point for low-temperature fixing while maintaining sufficient molecular entanglement and intermolecular forces to prevent hot offsetting.
Solution Approach 2:
The invention creates local quality differentiation within the binder resin by using a bimodal or multimodal molecular weight distribution. The lower molecular weight components (number average 2,000-20,000) provide low-temperature fusibility, while the higher molecular weight components (weight average 5,000-50,000) maintain hot offset resistance through stronger intermolecular interactions.
3Temperature
If the inertia square radius of binder resin components is reduced to improve low temperature fixability, then fixing temperature is lowered, but mechanical strength deteriorates
Solution Approach 1:
The invention changes the molecular size parameter by controlling the inertia square radius to 0.5-2.0 nm through optimized molecular weight distribution (weight average 5,000-50,000, number average 2,000-20,000). This reduced inertia square radius enables low-temperature fixing by lowering the melting point, while the controlled polydispersity index (1.2-2.0) ensures adequate mechanical strength through proper molecular chain entanglement.
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 good combination of low temperature fixability, high temperature preservability, and stress resistance, producing glossy images even at high fixing speeds without compromising mechanical strength or hot offset resistance.
Implementation Method 1
when the o-dichlorobenzene-soluble components of the resin is subjected to a viscosity analysis using a high temperature GPC-Ralls-viscometer
Implementation Method 2
GPC-Ralls-viscometer
Implementation Method 3
a low-temperature fusible toner, which can fuse at a low fixing temperature
Data Source
AI summary
The toner includes at least a binder resin, and a colorant. The toner has properties such that the percentage W(3000) of components having a molecular weight of 3,000 or less in tetrahydrofuran-soluble components of the toner determined by a GPC-RALLS viscosity analysis is 20% by weight or less; the molecular weight Mp at the peak top of the main peak in the molecular weight distribution curve of the tetrahydrofuran-soluble components is from 4,000 to 10,000; and the ratio Rt(Mp)/Rs(Mp) of an inertia square radius Rt(Mp) at the molecular weight Mp to an inertia square radius Rs(Mp) of linear polystyrene at the molecular weight Mp is greater than 0.98, wherein the inertia square radius Rs(Mp) is determined from a working curve obtained by subjecting plural polystyrenes having different molecular weights to the GPC-RALLS viscosity analysis.