Polyester Toner Composition for Low-Temperature Fixing and Blooming Resistance
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Solution Overview
Problem
Existing toners struggle to balance low-temperature fixability, image heat resistance, and blooming resistance, with crystalline polyesters improving fixability but compromising heat resistance, and nucleating agents enhancing heat resistance but risking blooming.
Innovation Solution
A toner composition comprising an amorphous polyester and a crystalline polyester, with specific SP value differences and carbon number relationships, to phase-separate and control compatibility, enhancing low-temperature fixability and image heat resistance while suppressing blooming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a crystalline polyester is used as binder resin to improve low-temperature fixability, then fixing temperature is reduced, but image heat resistance deteriorates
Solution Approach 1:
The binder resin is segmented into two distinct components: an amorphous polyester (resin A) providing low-temperature fixability through its plasticizing effect, and a crystalline polyester (resin C) providing image heat resistance through its crystalline structure. This segmentation allows each component to independently contribute its advantageous properties without the drawbacks of using a single crystalline polyester
Solution Approach 2:
The invention uses a composite binder resin system combining amorphous polyester and crystalline polyester in specific proportions (resin A:resin C = 95:5 to 50:50 by mass). This composite material approach enables the simultaneous achievement of low-temperature fixability (from amorphous component) and image heat resistance (from crystalline component), resolving the contradiction between these two properties
2Ease of operation
If a crystalline polyester is excessively compatible with binder resin to improve low-temperature fixability, then fixing performance is enhanced, but blooming resistance decreases
Solution Approach 1:
The invention controls the SP value difference between resin A and resin C to be 0.80 (cal/cm³)⁰·⁵ or less, optimizing the compatibility parameter. This specific parameter control ensures sufficient compatibility for low-temperature fixability while preventing excessive compatibility that would cause blooming. The SP value serves as a quantitative parameter to balance fixability and blooming resistance
3Reliability
If a nucleating agent is added to improve image heat resistance, then crystallization rate increases, but blooming resistance deteriorates
Solution Approach 1:
The invention extracts and eliminates the nucleating agent component from the toner formulation. Instead of using a nucleating agent to promote crystallization, the invention relies on the inherent crystalline structure of polyester resin C, which provides both rapid crystallization and excellent blooming resistance. This removal of the nucleating agent resolves the contradiction between heat resistance improvement and blooming resistance deterioration
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, image heat resistance, and blooming resistance by optimizing the amorphous and crystalline polyester segments' affinity and compatibility, ensuring efficient crystallization and reduced crystal migration.
Implementation Method 1
A toner composition comprising an amorphous polyester and a crystalline polyester, with specific SP value differences and carbon number relationships, to phase-separate and control compatibility
Implementation Method 2
ensuring efficient crystallization and reduced crystal migration
Implementation Method 3
blooming, in which crystalline materials such as wax and crystalline polyester are exposed on the toner surface, may occur with the passage of time
Data Source
AI summary
A toner comprising a toner particle comprising a binder resin, wherein the binder resin comprises an amorphous polyester A and a crystalline polyester C; the amorphous polyester A has an amorphous polyester segment a1 and a2; the amorphous polyester segment a2 has a monomer unit of a specific alcohol a0; the crystalline polyester C is a polymer having a crystalline polyester segment c2 and a crystalline segment c1 bonded to the end of the crystalline polyester segment c2; the crystalline polyester segment c2 has a monomer unit of a specific alcohol b0; an absolute value of a difference between a carbon number of the linear aliphatic polyhydric alcohol a0 and a carbon number of the linear aliphatic polyhydric alcohol b0 is 4 or less; and SP values of the polyester segment a1 and a2, and the crystalline segment c1 and the crystalline polyester segment c2 satisfy specific relationships.