Amorphous and Crystalline Polyester Toner Binder for Low-Temperature Fusing
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Solution Overview
Problem
In electrophotography, toners face challenges in achieving low-temperature fusing ability while maintaining heat-resistant storage properties and durability, especially in high-speed machines where energy transmission is limited, and existing solutions compromise on either low-temperature fusing or durability.
Innovation Solution
A resin binder composition for toners is developed by mixing amorphous polyester, obtained from polyethylene terephthalate, with crystalline polyester, where the crystalline polyester is present in an amount of 0.3 to 2.5 times the mass of the amorphous polyester, enhancing low-temperature fusing ability and heat-resistant storage properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a toner uses resin binders with easily adjusted components to improve thermal properties, then low-temperature fusing ability is improved, but heat-resistant storage properties and durability deteriorate
Solution Approach 1:
The invention uses a composite resin binder system containing both amorphous polyester and crystalline polyester in specific proportions. The amorphous polyester (obtained by polycondensing polyethylene terephthalate with alcohol and carboxylic acid components) provides low-temperature fusing ability, while the crystalline polyester maintains heat-resistant storage properties and durability. This composite approach allows both contradictory requirements to be satisfied simultaneously.
Solution Approach 2:
The invention optimizes the compositional parameters of the resin binder by controlling the ratio of amorphous polyester to crystalline polyester, and by adjusting the molecular weights and compositions of the polyester components. Specifically, the amorphous polyester has a number-average molecular weight of 10,000-50,000 and the crystalline polyester has a number-average molecular weight of 20,000-100,000, with their combined composition fine-tuned to achieve both low-temperature fusing and heat-resistant storage properties.
2Productivity
If a toner is designed for high-speed printing, then productivity is improved, but energy transmission becomes limited making low-temperature fusing difficult
Solution Approach 1:
The invention modifies the thermal parameters of the toner by using a composite polyester resin system with optimized molecular weights and compositions. The amorphous polyester component lowers the melting point and softening temperature of the toner, enabling effective fusing at reduced temperatures. This allows high-speed printing operations to achieve proper toner fusion even with limited energy transmission from the fuser unit.
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 composition effectively balances low-temperature fusing ability with heat-resistant storage properties and durability, improving the performance of toners in electrophotographic processes.
Implementation Method 1
a resin binder composition for use in a toner containing an amorphous polyester and a crystalline polyester... capable of satisfying low-temperature fusing ability with heat-resistant storage property and durability
Data Source
AI summary
A method for producing a toner for electrostatic image development, including the steps of (1) polycondensing an alcohol component, a carboxylic acid component, and polyethylene terephthalate to provide an amorphous polyester; and (2) subjecting the amorphous polyester obtained in the step (1) and components containing a crystalline polyester in an amount of from 0.3 to 2.5 times the mass of the components derived from the polyethylene terephthalate in the amorphous polyester to a process for producing a toner. The toner for electrostatic image development obtained by the method of the present invention is suitably used in development or the like of latent images formed in, for example, an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or the like.