Liquid Developer Toner Dispersion Stability via Binder Resin Control
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Solution Overview
Problem
The use of basic toner particle dispersing agents in liquid developers for electrophotographic systems leads to a decline in volume resistivity over time, affecting toner particle migration performance and image quality due to the elution of low-molecular-weight binder resin components into the carrier liquid.
Innovation Solution
A liquid developer formulation with a binder resin having an acid value of at least 10 mg KOH/g, a low-molecular-weight component acid value not exceeding 5 mg KOH/g, and a hydroxyl value not exceeding 10 mg KOH/g, utilizing a primary amine as the basic toner particle dispersing agent to retain the dispersing agent on the toner particle surface, thereby preventing elution and maintaining volume resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a basic toner particle dispersing agent is used to achieve excellent toner particle dispersion stability, then the volume resistivity of the liquid developer declines during storage
Solution Approach 1:
The patent changes the molecular weight parameter of the binder resin to ≥2,000 and controls the acid value parameter to ≥10 mg KOH/g. These parameter changes reduce the elution of binder resin components into the carrier liquid, thereby preventing the volume resistivity decline that normally occurs when basic dispersing agents are used, while still maintaining good dispersion stability.
2Stability of the object's composition
If a basic toner particle dispersing agent is used to improve toner particle dispersion, then toner particle migration performance is reduced due to elution into carrier liquid
Solution Approach 1:
By changing the molecular weight parameter of the binder resin to ≥2,000 and controlling the acid value to ≥10 mg KOH/g, the patent reduces the elution of binder resin components into the carrier liquid. This prevents the basic dispersing agent from being released into the carrier liquid, thereby maintaining both good dispersion stability and toner particle migration performance.
3Quantity of substance
If low-molecular-weight binder resin components are present to facilitate dispersing agent bonding, then elution into carrier liquid increases causing volume resistivity decline
Solution Approach 1:
The patent changes the molecular weight parameter of the binder resin to ≥2,000, which is sufficiently high to prevent elution into the carrier liquid while still maintaining adequate bonding capability with the basic dispersing agent through the controlled acid value of ≥10 mg KOH/g. This eliminates the harmful elution effect while preserving the necessary chemical interaction.
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
This approach enhances toner particle dispersion stability and suppresses the reduction in volume resistivity over time, ensuring consistent image quality and performance in electrophotographic systems.
Implementation Method 1
a basic toner particle dispersing agent is present bonded to this low-molecular-weight binder resin
Data Source
AI summary
A liquid developer comprising: a toner particle containing binder resin; a carrier liquid; and a basic toner particle dispersing agent, wherein the basic toner particle dispersing agent is a primary amine, an acid value of the binder resin is at least 10 mg KOH/g, an acid value of a component having a molecular weight of not more than 2,000 contained in the binder resin is not more than 5 mg KOH/g, and a hydroxyl value of the component having a molecular weight of not more than 2,000 contained in the binder resin is not more than 10 mg KOH/g.