Crystalline Polyester Toner Resolving Fixing Temperature and Storability Trade-off
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Solution Overview
Problem
Existing toners for developing electrostatic images face challenges in achieving both low temperature fixability and heat resistance storability, as the introduction of crystalline polyester into the binder resin may not fully exhibit its functions, leading to inconsistent performance in fixing and storage conditions.
Innovation Solution
A toner composition featuring a crystalline polyester resin with specific molecular weight ranges and a crystalline polyester segment dispersed within an amorphous segment, ensuring intermolecular forces maintain dispersion and prevent bleedout, thereby achieving both low temperature fixability and heat resistance storability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If crystalline polyester is introduced into the binder resin, then low temperature fixability is improved, but heat resistance storability deteriorates due to fusion of crystalline polyester or bleed out from amorphous polyester
Solution Approach 1:
The patent changes the molecular weight parameters of the crystalline polyester components. Specifically, it uses crystalline polyester with weight average molecular weight of 5,000 to 20,000 in the binder resin and crystalline polyester segment with weight average molecular weight of 500 to 3,000 in the amorphous polyester. This parameter optimization allows the crystalline polyester to maintain dispersion stability at storage temperatures while still providing low temperature fixability, resolving the contradiction between fixing performance and storability
Solution Approach 2:
The patent creates a composite binder resin system combining amorphous polyester and crystalline polyester in specific proportions (crystalline polyester content of 20-80 mass%). The amorphous polyester matrix provides thermal stability and prevents bleedout, while the dispersed crystalline polyester segments provide low temperature fixability. This composite structure allows both functionalities to coexist without interfering with each other
2Temperature
If crystalline polyester is dispersed in amorphous polyester using dispersant, then low temperature fixability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent extracts and eliminates the dispersant component from the system. Instead of using external dispersants to maintain crystalline polyester dispersion, the invention relies on the intrinsic molecular weight characteristics and phase compatibility between the crystalline polyester and amorphous polyester components. This removal of dispersants simplifies the manufacturing process and reduces the number of materials that need to be handled and controlled
Solution Approach 2:
The amorphous polyester matrix inherently provides the dispersion medium function without requiring additional dispersant agents. The crystalline polyester segments self-disperse within the amorphous polyester matrix through compatible molecular interactions and appropriate molecular weight selection. This self-service mechanism eliminates the need for complex dispersant addition and mixing procedures
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 resistance storability by maintaining the crystalline polyester segment's dispersion, preventing bleedout and ensuring compatibility, thus enhancing the toner's performance in various environmental conditions.
Implementation Method 1
ensuring intermolecular forces maintain dispersion and prevent bleedout
Implementation Method 2
achieves constant low temperature fixability
Implementation Method 3
toner for developing electrostatic latent images
Data Source
AI summary
A toner for developing electrostatic images contains a first resin and a second resin. The first resin is a crystalline polyester resin composed of a dicarboxylic acid unit and a dialcohol unit. The first resin has a weight average molecular weight of 5000 to 100000. The second resin has a weight average molecular weight of 5000 to 60000. The second resin is a polyester resin composed of a crystalline segment and an amorphous segment. The crystalline segment has a weight average molecular weight of 200 to 3000 and is composed of a dicarboxylic acid unit and a dialcohol unit. In the toner, a specific carbon number relationship is present between each unit.