Toner Phase Separation for Heat Resistance and Offset
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Solution Overview
Problem
Existing electrostatic charge image developing toners face issues with image deletion in high temperature and high humidity environments due to insufficient heat resistance and offset on thick recording media in low temperature and low humidity environments, primarily due to inadequate phase separation between amorphous and crystalline resins.
Innovation Solution
The toner particles are formulated with a specific ratio of amorphous and crystalline resins, where the phase-separated amount of crystalline resin from the amorphous resin is controlled to ensure a suitable compatibility, as measured by differential scanning calorimetry, to maintain heat resistance and prevent aggregation and offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the phase separation between amorphous and crystalline resins is increased to improve heat resistance, then image deletion is prevented in high temperature and high humidity environments, but offset occurs on thick recording media in low temperature and low humidity environments
Solution Approach 1:
The invention changes the chemical composition parameters of the resins by introducing a polyester resin with specific structural features (aliphatic dicarboxylic acid component of 5-30 mol%, cyclic carbonate component of 5-30 mol%) to achieve optimal phase separation. This compositional adjustment allows the toner to maintain appropriate compatibility between amorphous and crystalline resins, preventing both image deletion in high temperature/high humidity conditions and offset on thick recording media in low temperature/low humidity conditions.
Solution Approach 2:
The invention uses a composite resin system combining amorphous resin and crystalline resin in specific proportions (amorphous resin 70-95 wt%, crystalline resin 5-30 wt%). This composite structure creates controlled phase separation that provides both heat resistance for preventing image deletion and sufficient compatibility for preventing offset, resolving the contradiction between these two opposing requirements.
2Object-affected harmful factors
If the phase separation between amorphous and crystalline resins is decreased to prevent offset on thick recording media, then offset is prevented in low temperature and low humidity environments, but image deletion occurs in high temperature and high humidity environments
Solution Approach 1:
The invention adjusts the chemical composition parameters by incorporating specific functional groups (carboxyl group, hydroxyl group, or amino group) and controlling the content of aliphatic dicarboxylic acid and cyclic carbonate components. These parameter changes optimize the intermolecular forces and compatibility between resins, enabling the toner to maintain appropriate adhesion for offset prevention while retaining sufficient heat resistance to prevent image deletion.
Solution Approach 2:
The invention employs a composite material system with amorphous resin providing flexibility and adhesion (preventing offset) and crystalline resin providing structural stability and heat resistance (preventing image deletion). The specific composition ratio and phase separation control create a balanced composite that simultaneously addresses both opposing requirements.
3Stability of the object's composition
If the compatibility between amorphous and crystalline resins is increased to prevent aggregation, then toner aggregation is prevented in high temperature and high humidity environments, but the heat resistance becomes insufficient leading to image deletion
Solution Approach 1:
The invention optimizes the chemical composition parameters including the types and amounts of functional groups (carboxyl, hydroxyl, amino), the ratio of aliphatic dicarboxylic acid (5-30 mol%), and cyclic carbonate (5-30 mol%). These parameter adjustments create optimal intermolecular interactions that prevent toner aggregation through controlled compatibility while maintaining sufficient heat resistance by preserving appropriate phase separation between amorphous and crystalline domains.
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
This formulation effectively prevents image deletion in high-speed image formation at high temperatures and high humidity, and offset on thick recording media in low temperature and low humidity conditions, ensuring stable image formation across varying environmental conditions.
Implementation Method 1
the phase-separated amount of crystalline resin from the amorphous resin is controlled to ensure a suitable compatibility
Implementation Method 2
when the toner particles are subjected to a measurement by differential scanning calorimetry (DSC) before and after being stored
Data Source
AI summary
An electrostatic charge image developing toner includes toner particles including an amorphous resin and a crystalline resin, wherein, when the toner particles are subjected to a measurement by differential scanning calorimetry (DSC) before and after being stored at a temperature of 50° C. and a humidity of 90% RH for 24 hours, a relationship between an onset temperature T1 (° C.) of an endothermic peak having the lowest peak temperature in a first heating step with respect to the toner particles before being stored and an onset temperature T2 (° C.) of an endothermic peak having the lowest peak temperature in a first heating step with respect to the toner particles after being stored satisfies Expression (1): 2<T2−T1<10.