Toner Binder Resin Composite for Low Temperature Fixing
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Solution Overview
Problem
Conventional toners using crystalline resins suffer from rapid softening during heat generation in the developing device, leading to aggregation of toner particles and the formation of voids in images, which compromises low temperature fixability and heat resistant storage stability.
Innovation Solution
A toner with a binder resin comprising a crystalline resin containing urethane or urea bonds, synthesized through a one-shot method using a crystalline polyester unit, low-molecular weight polyisocyanate, and polyol or polyamine, with specific endothermic peak temperatures and ratios to control melting properties and prevent aggregation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the softening point of the binder resin is lowered to achieve low temperature fixability, then the fixing temperature can be reduced, but hot offset occurs and heat resistant storage stability degrades
Solution Approach 1:
The binder resin is formulated as a composite system containing crystalline resin (5-30 mass%) with specific melting characteristics (50-80°C) combined with amorphous resin. This composite structure enables the toner to soften at low temperatures for easy fixing while the crystalline structure provides thermal stability to prevent hot offset and maintain storage stability at higher temperatures.
Solution Approach 2:
The invention precisely controls the melting point parameter of the crystalline resin to be within 50-80°C and sets the content ratio of crystalline to amorphous resin between 5-30 mass% and 70-95 mass% respectively. By optimizing these parameters, the toner achieves a balance between low temperature fixability and heat resistant storage stability, preventing both cold offset and hot offset.
2Temperature
If conventional crystalline resins are used to achieve low temperature fixability, then the melting point is reduced, but toner particles aggregate during heat generation in the developing device
Solution Approach 1:
The binder resin combines crystalline resin with amorphous resin in specific proportions (5-30 mass% crystalline, 70-95 mass% amorphous). The amorphous resin component provides continuous phase stability and prevents particle aggregation during heat generation in the developing device, while the crystalline resin provides the low melting point for fixability.
Solution Approach 2:
The invention controls the melting point of the crystalline resin to be within 50-80°C and optimizes the crystalline-to-amorphous resin ratio. This parameter optimization ensures that the toner particles maintain adequate melting properties for low temperature fixing while the amorphous resin matrix prevents aggregation during storage and development.
3Temperature
If the melting point of the binder resin is reduced for low temperature fixing, then fixing becomes easier, but toner particles fuse together during storage
Solution Approach 1:
The binder resin uses a composite of crystalline and amorphous resins where the crystalline resin (5-30 mass%) provides sharp melting at 50-80°C for low temperature fixing, while the amorphous resin (70-95 mass%) provides thermal stability during storage. The amorphous resin acts as a stabilizing matrix that prevents particle fusion during storage while allowing easy fixing during operation.
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 excellent low temperature fixability and heat resistant storage stability while preventing toner particle aggregation in the developing device, ensuring high-quality image formation without voids.
Implementation Method 1
a crystalline resin is used as a binder resin of the toner. The crystalline resin is capable of decreasing the softening point of the toner to around the melting point thereof by sharply softening at the melting point of the resin
Implementation Method 2
The crystalline resin is capable of decreasing the softening point of the toner to around the melting point thereof by sharply softening at the melting point of the resin
Implementation Method 3
a maximum endothermic peak temperature (P1) of from 50°C to 80°C and a total endothermic amount (Q) of from 35 J/g to 90 J/g
Data Source
Figure 1A~1B
Figure 2~3
Figure 4
AI summary
Provided is a toner containing a binder resin. The binder resin contains a crystalline resin. The toner has a maximum endothermic peak temperature (P1) of from 50°C to 80°C and a total endothermic amount (Q) of from 35 J/g to 90 J/g at a first temperature elevation of differential scanning calorimetry. A ratio (Qp/Q) of a total endothermic amount (Qp) of the toner in a temperature range of from 20°C to the maximum endothermic peak temperature (P1) to the total endothermic amount (Q) of the toner is from 0.65 to 0.83.