Toner Resin Compatibility for High Humidity Fixing
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Solution Overview
Problem
In electrophotographic image forming, toners with amorphous and crystalline resins face challenges in maintaining reproducibility of fine lines on thick recording media in high temperature and high humidity environments, leading to decreased adhesion and charging ability due to phase separation, which results in contamination and reduced image quality.
Innovation Solution
The development of an electrostatic charge image developing toner with a specific composition of amorphous and crystalline resins, where the crystalline resin is phase-separated to a minimal extent, ensuring a high compatible portion with the amorphous resin, thereby enhancing adhesion and preventing contamination, as measured by a differential scanning calorimetry ratio x/y < 0.3.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If toner particles include both amorphous resin and crystalline resin, then low-temperature fixing properties are improved, but phase separation occurs in high temperature and high humidity environments leading to decreased adhesion and charging ability
Solution Approach 1:
The invention changes the molecular structure parameters of the crystalline resin by introducing specific side chains (alicyclic hydrocarbon groups with 6-10 carbon atoms) to modify the resin's compatibility characteristics. This structural parameter change prevents phase separation while maintaining the desired thermal properties for low-temperature fixing
Solution Approach 2:
The invention creates a composite resin system where the crystalline resin and amorphous resin are specifically designed to be compatible with each other. The crystalline resin contains both a main chain and side chains with specific chemical structures that ensure compatibility, forming a stable composite material that maintains uniformity under various environmental conditions
2Productivity
If crystalline resin is phase-separated to improve low-temperature fixing, then fixing efficiency increases, but adhesion force decreases leading to contamination
Solution Approach 1:
The invention modifies the chemical structure parameters of the crystalline resin by incorporating specific side chains that prevent excessive phase separation. This structural modification allows the resin to maintain adequate adhesion force while still achieving sufficient crystallinity for efficient fixing, thereby preventing contamination
3Temperature
If toner particles are heated at 50°C and 50% RH for a week, then phase separation is accelerated, but this condition is used to measure compatibility ratio
Solution Approach 1:
The invention performs preliminary structural design of the crystalline resin with specific side chains that pre-establish compatibility between the crystalline and amorphous resins. This preliminary structural configuration ensures that even under accelerated aging conditions (50°C, 50% RH for one week), the resins maintain sufficient compatibility as evidenced by the x/y ratio being 0.30 or less
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 solution improves the adhesion force of external additives to toner particles, prevents contamination, and maintains the toner's charging ability, thereby enhancing the reproducibility of fine lines on thick recording media in challenging environmental conditions.
Implementation Method 1
when the toner particles are subjected to a measurement by differential scanning calorimetry before and after being heated
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 before and after being heated at a temperature of 50° C. and a humidity of 50% RH for a week, a relationship between an endothermic amount x (J/g) derived from the crystalline resin with respect to the toner particles before being heated and an endothermic amount y (J/g) derived from the crystalline resin with respect to the toner particles after being heated satisfies Expression (1): x/y<0.3.