Urethane-Modified Polyester Resin for Liquid Developer Fixation
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Solution Overview
Problem
Liquid developers face a challenge in achieving both low-temperature fixability and heat resistance, which are conflicting characteristics, leading to a trade-off in damage resistance and fixability, with existing solutions either compromising on image density or experiencing document offset during high-temperature storage.
Innovation Solution
A liquid developer is formulated with a urethane-modified polyester resin having a specific molecular weight ratio (2.3≦Mw/Mn≦4) and a core/shell structure of toner particles, where the first resin constitutes at least 70% of the total resin, enhancing both low-temperature fixability and heat resistance while preventing document offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a liquid developer is designed for low-temperature fixability, then fixation performance is improved, but heat resistance deteriorates
Solution Approach 1:
The patent changes the molecular weight parameters of the polyester resin, specifically controlling Mw/Mn ratio between 2.0-4.0 and Mn between 10,000-50,000. This parameter optimization allows the resin to achieve both low-temperature fixability and heat resistance by balancing molecular weight distribution to prevent both premature melting and excessive stability at high temperatures
Solution Approach 2:
The patent uses a composite resin system combining polyester resin with urethane modification. The urethane groups (0.5-5% concentration) introduced through isocyanate compounds create a composite material that balances softening characteristics for low-temperature fixation with structural stability for heat resistance, resolving the contradiction between the two opposing requirements
2Reliability
If a liquid developer is designed for heat resistance, then stability at high temperature is improved, but low-temperature fixability deteriorates
Solution Approach 1:
The patent optimizes the molecular weight parameters of the polyester resin, specifically controlling Mw/Mn ratio between 2.0-4.0 and Mn between 10,000-50,000. This parameter optimization allows the resin to achieve both low-temperature fixability and heat resistance by balancing molecular weight distribution to prevent both premature melting and excessive stability at high temperatures
Solution Approach 2:
The patent uses a composite resin system combining polyester resin with urethane modification. The urethane groups (0.5-5% concentration) introduced through isocyanate compounds create a composite material that balances softening characteristics for low-temperature fixation with structural stability for heat resistance, resolving the contradiction between the two opposing requirements
3Reliability
If the molecular weight of the polyester resin is increased to improve heat resistance, then stability is improved, but damage resistance of the document deteriorates
Solution Approach 1:
The patent precisely controls the molecular weight parameters, setting Mn between 10,000-50,000 and Mw/Mn between 2.0-4.0. This controlled molecular weight range ensures the resin has sufficient strength for document damage resistance while maintaining heat resistance, preventing both brittleness and excessive softness
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 solution ensures excellent low-temperature fixability, heat resistance, and damage resistance of documents, preventing document offset and maintaining image quality by controlling the molecular weight distribution of the urethane-modified polyester resin within the specified range.
Implementation Method 1
a first resin which is a urethane-modified polyester resin resulting from increase in chain length of a component derived from a polyester resin by a compound containing an isocyanate group
Data Source
AI summary
A resin in a liquid developer contains a first resin which is a urethane-modified polyester resin resulting from increase in chain length of a component derived from a polyester resin by a compound containing an isocyanate group and a second resin. The first resin is contained by not lower than 70 mass % with respect to a total of the first resin and the second resin. The component derived from the polyester resin includes a constitutional unit derived from an acid component and a constitutional unit derived from an alcohol component. A ratio of a constitutional unit derived from an aliphatic monomer occupied in the constitutional unit derived from the acid component and the constitutional unit derived from the alcohol component is not lower than 80 mass %. Relation of 2.3≦Mw/Mn≦4 (10000≦Mn≦50000) is satisfied.