Toner Binder Resin Crystallinity Control
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Solution Overview
Problem
Conventional toners face challenges with low temperature fixing performance, offset resistance, storage stability, durability, and resistance to contamination of photo-sensitive materials, particularly during high-speed printing, where image quality is compromised due to bleeding, staining, and contamination issues.
Innovation Solution
A binder resin for toners is developed, comprising a carboxyl group-containing vinyl resin, a glycidyl group-containing vinyl resin, and a saturated crystalline polyester with specific properties, including a metal component derived from a fatty acid metal salt, which enhances low temperature fixing, offset resistance, smear resistance, storage stability, and durability by controlling crystallinity and viscoelastic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If low temperature fixing performance is improved, then fixing at lower temperatures is achieved, but storage stability deteriorates and toner agglomerates and solidifies over time
Solution Approach 1:
The invention changes the chemical composition parameters of the binder resin by incorporating specific ratios of amorphous resin (30-70 mass%) and crystalline resin (70-30 mass%), along with controlling the gel fraction (5-50%). This parameter optimization enables the resin to maintain appropriate softness at low fixing temperatures while preserving storage stability through controlled crystallinity and crosslinking.
Solution Approach 2:
The invention uses a composite binder resin system combining amorphous resin and crystalline resin in specific proportions. The amorphous resin component provides low-temperature flexibility and fixing performance, while the crystalline resin component maintains structural integrity and storage stability. This composite approach resolves the contradiction between low-temperature fixing and storage stability.
2Object-generated harmful factors
If crosslinking of high molecular weight portion is performed, then offset resistance is improved, but fixing performance and smear resistance are insufficient
Solution Approach 1:
The invention optimizes the crosslinking degree by controlling the gel fraction within 5-50% and adjusting the functional group content (carboxyl groups 1-50 meq/kg, hydroxyl groups 1-50 meq/kg). This controlled crosslinking provides sufficient offset resistance while maintaining the resin's ability to melt and fix properly, avoiding excessive crosslinking that would harm fixing performance.
Solution Approach 2:
The invention applies crosslinking selectively to specific portions of the resin structure rather than uniform crosslinking throughout. By controlling the gel fraction and functional group distribution, crosslinking is concentrated in regions that provide offset resistance while leaving other regions capable of proper melting and fixing behavior.
3Reliability
If durability is improved to prevent toner breaking, then resistance to contamination of photo-sensitive material is improved, but image quality may be compromised
Solution Approach 1:
The invention adjusts the molecular weight distribution and gel fraction parameters to achieve optimal durability. The controlled crosslinking structure prevents toner particle fragmentation during high-speed printing while maintaining smooth melting characteristics that ensure sharp image edges and prevent contamination of the photo-sensitive material.
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 binder resin achieves improved low temperature fixing performance, reduced offset and smear resistance, enhanced storage stability, and increased durability, preventing contamination of photo-sensitive materials and maintaining image quality during high-speed printing.
Implementation Method 1
a metal component (M) selected from Zn, Ca, Mg, Al and Ba is dispersed in the saturated crystalline polyester (S)
Implementation Method 2
the loss modulus (G'') of said binder resin for a toner at 120 degrees centigrade is equal to or more than 0.3×10^4
Implementation Method 3
the loss modulus (G'') of said binder resin for a toner at 120 degrees centigrade is equal to or more than 0.3×10^4
Data Source
AI summary
Disclosed is a binder resin for a toner containing at least a carboxyl group-containing vinyl resin (C), a glycidyl group-containing vinyl resin (E), a reaction product of the vinyl resins and a saturated crystalline polyester (S), wherein the saturated crystalline polyester (S) has a predetermined melting point and a predetermined metal component (M), and the binder resin for a toner has a predetermined loss modulus (G") and a predetermined storage modulus (G').