Electrostatic Toner Core-Shell Structure for Fixability and Stability
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Solution Overview
Problem
The existing toner disclosed in Patent Literature 1 has insufficient reduction of alkali metal elements inside the toner particles, leading to decreased charge characteristics due to lower resistance values and increased water adsorption, which affects charge stability and fixability.
Innovation Solution
An electrostatic latent image developing toner with toner particles having a core covered by a shell layer containing a hydrophobic thermoplastic resin and a positively chargeable hydrophilic water-insoluble resin, where the alkali metal elements in the surface layer and the toner particles satisfy specific concentration ratios to minimize water adsorption and maintain charge stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a binder resin having a low melting point or a low glass transition point is used to improve low-temperature fixability, then fixability is improved, but toner particles tend to agglomerate when preserved at high temperatures
Solution Approach 1:
The toner is divided into two distinct parts: a core containing the binder resin for fixability, and a shell layer containing hydrophobic resin to prevent agglomeration. This segmentation allows each part to fulfill its specific function without compromising the other.
Solution Approach 2:
The invention uses a composite structure combining different resin materials with complementary properties. The core uses low-melting-point binder resin for fixability, while the shell uses hydrophobic resin for stability, creating a composite toner that achieves both goals simultaneously.
2Reliability
If hydrophilic polar groups are present at surfaces of toner particles to improve charge characteristics, then charge ability is enhanced, but water adsorption increases and charge stability decreases
Solution Approach 1:
The shell layer is designed with specific local properties: it contains hydrophobic groups that repel water while maintaining positive chargeability. This local quality modification at the particle surface prevents water adsorption while preserving charge characteristics.
Solution Approach 2:
The invention changes the chemical parameters of the surface layer by incorporating hydrophobic resin components and controlling the ratio of hydrophilic to hydrophobic groups. This parameter adjustment reduces water adsorption affinity while maintaining charge ability.
3Reliability
If alkali metal elements are reduced at surfaces of toner particles to improve charge stability, then charge stability is enhanced, but resistance value inside particles decreases and charge amount decreases
Solution Approach 1:
The shell layer is designed with specific local properties: it contains hydrophobic resin components that repel water while maintaining positive chargeability. This local quality modification at the particle surface prevents water adsorption while preserving charge ability.
Solution Approach 2:
The shell layer uses a composite approach combining hydrophobic resin with charge control agents. This composite structure allows the surface to repel water while maintaining adequate chargeability through the combined effects of the resin matrix and charge control additives.
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 charge characteristics and improved high-temperature preservability and low-temperature fixability by controlling alkali metal element distribution and resistance values, enhancing charge stability and fixability.
Implementation Method 1
The shell layer contains a hydrophobic thermoplastic resin and a positively chargeable hydrophilic water-insoluble resin
Implementation Method 2
electrostatic latent image developing toner
Data Source
AI summary
An electrostatic latent image developing toner includes a plurality of toner particles each including a toner core and a shell layer covering a surface of the toner core. The shell layer contains a hydrophobic thermoplastic resin and a positively chargeable hydrophilic water-insoluble resin. An existing amount A of alkali metal elements present in a surface layer of the shell layer measured by X-ray photoelectron spectroscopy and an existing amount B of alkali metal elements present in a toner particle as a whole measured by fluorescent X-ray analysis satisfy expressions (a) and (b) shown belowA≤300 ppm (a)0.5≤A/B<1.0 (b).