Core-Shell Toner with Segmented Softening for Humidity Resistance
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Solution Overview
Problem
Current toners fail to maintain low temperature fixing ability at high temperatures and high humidity, leading to carrier spent and inadequate image formation in image forming apparatuses.
Innovation Solution
A toner with a core-shell structure containing a first binder resin, a second binder resin, a colorant, and a releasing agent, with a softening index of 86° C. to 95° C. and thermal hardness of 0.7 to 1.8, which is designed to prevent carrier spent and ensure effective image formation at high temperature and high humidity conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the softening temperature of the toner is decreased to improve low temperature fixing ability, then the fixing temperature is reduced, but the carrier becomes contaminated and carrier spent occurs at high temperature and high humidity
Solution Approach 1:
The toner is divided into core and shell regions with different compositions and functions. The core contains low melting point components for low temperature fixing, while the shell contains high melting point components that resist contamination at high temperature and high humidity, preventing carrier spent.
Solution Approach 2:
Different regions of the toner particle have different properties: the core has low softening temperature for fixing ability, while the shell has high softening temperature and hydrophobicity for contamination resistance. This local differentiation allows simultaneous achievement of low temperature fixing and carrier protection.
2Temperature
If a core-shell toner with releasing agent is used to improve low temperature fixing ability, then the fixing temperature is reduced, but the problem of carrier spent at high temperature and high humidity is not solved
Solution Approach 1:
The toner uses a composite structure combining hydrophobic releasing agent in the core with hydrophobic resin in the shell. This composite material approach provides both low temperature fixing ability (from releasing agent) and resistance to carrier contamination at high temperature and high humidity (from shell's hydrophobicity).
Solution Approach 2:
The softening temperature of the shell is specifically controlled to be higher than the storage temperature (e.g., higher than 45°C) to prevent the shell from softening and causing carrier contamination under high temperature and high humidity storage conditions, while the core maintains low softening temperature for fixing.
3Use of energy by stationary object
If the toner softening temperature is lowered for energy saving, then the fixing energy is reduced, but the toner component attaches to carrier and charging ability deteriorates
Solution Approach 1:
The toner is segmented into core and shell where the core provides low temperature fixing (energy saving) and the shell protects the carrier from contamination, maintaining carrier charging ability even when the core softening temperature is lowered.
Solution Approach 2:
The shell acts as an intermediary barrier between the low softening temperature core components and the carrier. It prevents direct contact and attachment of core components to the carrier, thereby maintaining carrier charging ability while allowing energy-efficient low temperature fixing.
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 fixing ability while preventing carrier spent, ensuring stable image formation and heat-resistant storage stability even at high temperatures and high humidity levels.
Implementation Method 1
a toner having low temperature fixing ability... a toner having a low temperature fixing ability at high temperature and high humidity
Implementation Method 2
the toner has a softening index of 86° C. to 95° C. and a thermal hardness of 0.7 to 1.8
Data Source
AI summary
A toner containing: a core containing at least a first binder resin, a colorant, and a releasing agent; and a shell containing at least a second binder resin; wherein the toner has a core-shell structure, and has a softening index of 86° C. to 95° C. and a thermal hardness of 0.7 to 1.8.