Electrostatic Toner with Polyester-Coated PLA Particles
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Solution Overview
Problem
Conventional toner production methods face challenges in achieving low-temperature fixability while maintaining hot-offset resistance and stable image density and haze degree, particularly when using polylactic acid as a binder resin, due to issues with crystallinity, solubility, and dispersibility, leading to variations in charged amount and image quality under different environmental conditions.
Innovation Solution
The development of an electrostatic image developing toner with a structure where a polyester resin containing a polyhydroxycarboxylic acid skeleton is attached to a resin particle, using a polybasic acid and polyhydric alcohol, and a coated film, which improves solubility and crystallinity, and includes a mixture of L and D forms of lactic acid to enhance optical purity and dispersibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If polylactic acid is used as a binder resin, then environmental sustainability is improved, but low-temperature fixability deteriorates due to high ester linkage concentration
Solution Approach 1:
The patent modifies the chemical structure parameters of the polylactic acid by controlling the ester linkage concentration and molecular weight. Specifically, it uses polylactic acid with 30-70% ester linkage concentration and number-average molecular weight of 5,000-50,000, which balances environmental sustainability with adequate thermoplasticity for low-temperature fixing.
Solution Approach 2:
The patent creates a composite binder resin system by combining polylactic acid with other resins having complementary properties. This composite approach allows the polylactic acid to provide environmental sustainability while the combined resin system provides the necessary thermoplasticity and flow characteristics for low-temperature fixability.
2Object-affected harmful factors
If polylactic acid is used as a binder resin, then environmental sustainability is improved, but pulverizability deteriorates due to increased hardness
Solution Approach 1:
The patent optimizes the molecular weight parameter of polylactic acid to 5,000-50,000 (number-average), which prevents excessive crystallization and maintains adequate hardness for pulverization while retaining environmental benefits. This parameter control ensures the resin remains manufacturable through conventional pulverization processes.
3Stability of the object's composition
If high ester linkage concentration is used in polylactic acid, then structural stability is improved, but thermoplasticity deteriorates
Solution Approach 1:
The patent precisely controls the ester linkage concentration parameter within 30-70% range. This optimized concentration provides sufficient structural stability from the polylactic acid while preventing excessive hardness that would eliminate thermoplasticity, enabling both stability and temperature-dependent flow characteristics.
4Productivity
If toner composition is made brittle for pulverization, then productivity is improved, but particle size distribution broadens
Solution Approach 1:
The patent adjusts the molecular weight and ester linkage concentration parameters of the polylactic acid to achieve optimal brittleness. This controlled brittleness enables efficient pulverization for productivity while maintaining sufficient structural integrity to produce relatively uniform particle sizes, balancing manufacturing efficiency with particle size control.
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 exhibits superior low-temperature fixability and maintains excellent hot-offset resistance, image density, and environmental variability, providing stable performance across different conditions.
Implementation Method 1
a polyester resin containing a polyhydroxycarboxylic acid skeleton is attached to a resin particle
Implementation Method 2
includes a mixture of L and D forms of lactic acid to enhance optical purity and dispersibility
Data Source
AI summary
An electrostatic image developing toner including a toner particle (C), wherein the toner particle (C) has a structure in which a resin particle (A) containing at least a first resin (a) or a coated film (P) containing the first resin (a) is attached to a surface of a resin-containing particle (B) containing a second resin (b), and wherein the resin (b) includes a polyhydroxycarboxylic acid skeleton, and the resin (a) is a polyester resin containing a polybasic acid and a polyhydric alcohol.