Urethane-Modified Polyester Liquid Developer Fixability
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Solution Overview
Problem
Existing liquid developers face challenges in achieving both low-temperature fixability and heat resistance, making it difficult to improve fixability while maintaining these properties.
Innovation Solution
A liquid developer is formulated with urethane-modified polyester resin toner particles dispersed in an insulating liquid, where the resin contains 80% or more of a first resin with a specific constitutional unit ratio and urethane group concentration, and is transferred to a recording medium under controlled pressure and heating conditions to ensure optimal fixability and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-temperature fixability is improved, then fixability at low temperature is enhanced, but heat resistance deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the resin by specifying precise ratios of constitutional units (aliphatic monomer units ≥90 mass%) and urethane group concentration (0.8-5 mass%), which modifies the resin's thermal properties to simultaneously achieve low-temperature fixability and heat resistance
Solution Approach 2:
The patent uses a composite resin system combining polyester resin with isocyanate-modified polyester resin, where the specific composition ratios create a material that exhibits both low-temperature meltability for fixability and high-temperature stability for heat resistance
2Temperature
If heat resistance is improved, then thermal stability is enhanced, but low-temperature fixability deteriorates
Solution Approach 1:
The patent adjusts the molecular structure parameters by controlling the constitutional unit composition (≥90 mass% aliphatic monomers) and urethane group content (0.8-5 mass%), which creates a resin that maintains structural integrity at high temperatures while remaining processable at low temperatures
Solution Approach 2:
The patent creates different functional zones within the resin structure: the aliphatic monomer units provide thermal stability for heat resistance, while the urethane groups provide low-temperature meltability for fixability, with each component localized to specific functional roles
3Temperature
If toner particle melt is prevented, then heat resistance is improved, but fixability deteriorates
Solution Approach 1:
The patent optimizes the resin composition parameters (constitutional unit ratios and urethane group concentration) to control the melting behavior, preventing excessive melt at high temperatures while ensuring adequate flow at fixation temperatures
Solution Approach 2:
The patent uses the measured softening temperatures Tm1 and Tm5 under different loads to feedback-adjust the resin composition, ensuring that the difference |Tm1-Tm5|≥20°C maintains both heat resistance and fixability
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 provides a liquid developer with excellent low-temperature fixability and heat resistance, preventing toner particle melt and high-temperature offset, while maintaining image quality and glossiness.
Implementation Method 1
fixing toner particles contained in the liquid developer transferred to the recording medium to the recording medium... As the recording medium is heated, toner particles on the recording medium are heated
Implementation Method 2
The step of fixing the toner particles to the recording medium preferably includes the step of heating the recording medium. A heating condition in the step of heating the recording medium preferably satisfies relation of Tm5≦T1≦(Tm1+10° C.)
Data Source
AI summary
A resin in a liquid developer contains 80 mass % or more of a urethane-modified polyester resin. A component derived from a polyester resin contains 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 90 mass %. Relation of |Tm1−Tm5|≧20° C. 70° C.≦Tm1≦170° C., 60° C.≦Tm5≦120° C.) is satisfied, where Tm1 (° C.) represents a softening temperature T1/2 of toner particles measured with a flow tester under a load of 1 kg and Tm5 (° C.) represents a softening temperature T1/2 of toner particles measured with a flow tester under a load of 5 kg.