Core-Shell Resin Particles for Liquid Electrophotographic Developer Fixing
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Solution Overview
Problem
Existing nonaqueous dispersions of resin particles for electrophotography and inkjet applications face challenges in achieving uniform particle size distribution and stability, as well as satisfactory fixing properties, particularly in reducing power consumption and improving heat-resistant stability.
Innovation Solution
A nonaqueous dispersion of core-shell type resin particles is developed, where fine particles are adhered to or form a film on the surface of resin particles and are dispersed in a nonhydrophilic organic solvent, using a specific method involving mixing and reacting components to achieve uniformity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fatty acid monoester is added to plasticize the polyester resin, then the fixing property is improved, but the dispersion stability deteriorates and particle size distribution becomes poor
Solution Approach 1:
The resin particles are divided into a core component (polyester resin) and a shell component (resin with low solubility in the dispersion medium). This segmentation allows the core to provide fixing properties while the shell provides dispersion stability, resolving the contradiction between fixing property and dispersion stability.
Solution Approach 2:
The invention creates a composite resin particle structure combining polyester resin (for fixing) with another resin that has low solubility in the dispersion medium (for stability). This composite approach allows both functions to coexist without interfering with each other, solving the contradiction between fixing property and dispersion stability.
2Manufacturing precision
If resin particles with small particle diameter are used, then the particle size distribution is improved, but the manufacturing precision becomes difficult to control
Solution Approach 1:
The resin particles are prepared in advance with controlled size distribution before being used in the dispersion. By pre-controlling the particle size during manufacturing, the invention ensures narrow particle size distribution is achieved while maintaining ease of manufacture through established particle generation methods.
3Loss of energy
If printing machines operate at lower temperatures to decrease power consumption, then the energy efficiency is improved, but the fixing performance deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the resin particles by incorporating polyester resin with specific properties and combining it with another resin having low solubility in the dispersion medium. This parameter change enables the resin particles to maintain fixing performance at lower temperatures, allowing printing machines to operate with reduced power consumption while maintaining fixing reliability.
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 solution results in resin particles with uniform diameter and shape, exhibiting excellent heat-resistant stability and fixing properties, enhancing the performance of liquid developers for electrophotography and inkjet applications.
Implementation Method 1
fine particles (A) that either adhere to the surface of the resin particle (B) or form a film on the surface of the resin particle (B)
Implementation Method 2
resin particles (C) are dispersed in a nonhydrophilic organic solvent (L)
Data Source
AI summary
Provided is a nonaqueous dispersion of resin particles, in which the resin particles have uniform particle diameters and shapes and which exhibits excellent fixing properties, particularly when used as a liquid electrophotographic developer. More specifically, provided is a nonaqueous dispersion (X) in which resin particles (C) are dispersed in a nonhydrophilic organic solvent (L) that exhibits a relative permittivity of 1 to 4 at 20° C., the resin particles (C) being core-shell type resin particles each of which comprise a resin particle (B) that contains a resin (b) and fine particles (A) that contain a resin (a) and that either adhere to the surface of the resin particle (B) or form a film on the surface of the resin particle (B), wherein the solubility of (a) in (L) at 25° C. is 10 wt % or less relative to the weight of (a).