Core-Shell Polyester Toner for Low-Temperature Fixing
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Solution Overview
Problem
Electrophotographic processes face challenges in low-temperature, low-humidity environments where the fixing member may not reach sufficient temperature for proper toner fixation, leading to cold offset issues due to the use of polyester resins as binder resins.
Innovation Solution
An electrostatic-image developing toner with core and shell layers, where the core contains a first amorphous polyester resin with limited bisphenol-A backbone units and the shell contains a second amorphous polyester resin with a higher percentage of bisphenol-A backbone units, maintaining stable water content and reducing cold offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a toner containing polyester resin as binder resin is used to achieve low-temperature fixability, then low-temperature fixability is improved, but cold offset occurs in low-temperature, low-humidity environments
Solution Approach 1:
The invention changes the chemical composition parameters of the polyester resin by controlling the ratio of specific structural units (adipic acid units at 5-20 mass%, sebacic acid units at 5-20 mass%, and bisphenol-A backbone polyol units at 20-60 mass%). This parameter optimization allows the resin to maintain appropriate melt viscosity at low temperatures while preventing cold offset through balanced molecular structure
Solution Approach 2:
The invention uses a composite polyester resin system combining multiple structural units from different chemical components (adipic acid, sebacic acid, bisphenol-A backbone polyol, and other polyols). This composite structure integrates the low-temperature flow properties from adipic/sebacic acid units with the thermal stability from bisphenol-A units, resolving the contradiction between low-temperature fixability and offset resistance
2Use of energy by moving object
If the fixing member temperature is insufficient in low-temperature environments, then energy consumption is reduced, but toner image fixation quality deteriorates
Solution Approach 1:
The polyester resin parameters are optimized to have a glass transition temperature and melting point that enable effective fixation at lower temperatures. The specific composition (adipic acid 5-20 mass%, sebacic acid 5-20 mass%, bisphenol-A polyol 20-60 mass%) creates a resin that becomes sufficiently fluid at reduced temperatures to ensure proper toner bonding without requiring high energy input
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 toner achieves low-temperature fixability and offset resistance by maintaining sufficient water retention and decreasing melt viscosity, effectively reducing cold offset in low-temperature, low-humidity conditions.
Implementation Method 1
The core particle contains a first amorphous polyester resin containing structural units derived from a polycarboxylic acid and structural units derived from a polyol
Implementation Method 2
The shell layer contains a second amorphous polyester resin containing structural units derived from a polycarboxylic acid and structural units derived from a polyol. About 50% by mass or more of the structural units derived from the polyol are structural units derived from a polyol containing a bisphenol-A backbone
Implementation Method 3
The electrostatic-image developing toner has a water content of about 2.0% to about 5.0% by mass
Data Source
AI summary
An electrostatic-image developing toner contains toner particles, each including a core particle and a shell layer disposed on at least a portion of a surface of the core particle. The core particle contains a first amorphous polyester resin containing structural units derived from a polycarboxylic acid and structural units derived from a polyol. About 5% by mass or less of the structural units derived from the polyol are structural units derived from a polyol containing a bisphenol-A backbone. The shell layer contains a second amorphous polyester resin containing structural units derived from a polycarboxylic acid and structural units derived from a polyol. About 50% by mass or more of the structural units derived from the polyol are structural units derived from a polyol containing a bisphenol-A backbone. The electrostatic-image developing toner has a water content of about 2.0% to about 5.0% by mass.