Core-Shell Liquid Developer Toner for Hot Offset Prevention
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Solution Overview
Problem
Existing liquid developers for electrophotography and inkjet printing face challenges with hot offset due to low viscosity resins in core-shell structures, which affect fixability and energy efficiency, especially at low temperatures.
Innovation Solution
A liquid developer with toner particles having a core-shell structure where the second resin particles are coated with first resin particles, with specific molecular weight and urethane group concentration ranges, and a ratio of surface coverage to prevent hot offset and improve fixability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a core layer of the core-shell structure is composed of a resin of too low viscosity, then fixability of toner particles at low temperature is improved, but the resin is likely to remain on a fixation roller at the time of fixation at a high temperature, causing hot offset
Solution Approach 1:
The invention divides the resin structure into two distinct layers: a core layer containing low-viscosity resin for low-temperature fixability, and a shell layer containing high-viscosity resin to prevent hot offset. This segmentation allows each layer to perform its specific function without interfering with the other, resolving the contradiction between low-temperature fixability and hot offset prevention.
Solution Approach 2:
Different regions of the toner particle are assigned different resin properties: the core region contains low-viscosity resin optimized for low-temperature melting and fixability, while the shell region contains high-viscosity resin optimized for high-temperature stability and hot offset prevention. This local differentiation of material properties resolves the contradiction by having each region perform its specialized function.
2Temperature
If the second resin has low molecular weight, then the resin provides good low-temperature fixability, but it may compromise the structural integrity and elasticity at high temperatures
Solution Approach 1:
The invention creates a composite resin structure combining two resins with different molecular weights and properties: a low molecular weight second resin in the core for low-temperature fixability, and a high molecular weight first resin in the shell for high-temperature structural integrity. The composite structure allows the low molecular weight resin to provide low-temperature flow and bonding while the high molecular weight resin maintains structural strength at high temperatures.
Solution Approach 2:
The resin system is segmented into two functional components with different molecular weights: the second resin (low molecular weight) in the core provides low-temperature fixability, while the first resin (high molecular weight) in the shell provides high-temperature structural integrity. This segmentation resolves the contradiction by assigning different molecular weight requirements to different functional regions.
3Use of energy by moving object
If the toner particles have sharp-melting capability in low-temperature region for energy saving, then energy efficiency is improved, but it may compromise the elasticity and hot offset resistance
Solution Approach 1:
The toner particle structure is segmented into core and shell layers with different resin compositions: the core layer contains low-viscosity resin that melts sharply at low temperatures for energy efficiency, while the shell layer contains high-viscosity resin that maintains elasticity and prevents hot offset at high temperatures. This segmentation allows simultaneous achievement of energy efficiency and hot offset resistance.
Solution Approach 2:
Different regions of the toner particle are given different quality characteristics: the core region has low-viscosity resin for sharp melting and energy efficiency, while the shell region has high-viscosity resin for elasticity and hot offset resistance. This local quality differentiation resolves the contradiction by having each region optimized for its specific function.
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 enhances the fixability of toner particles, preventing hot offset and maintaining elasticity at high temperatures, thereby improving image quality and energy efficiency in low-temperature applications.
Implementation Method 1
dispersing toner particles in an insulating liquid
Implementation Method 2
first resin particles containing a first resin are attached to or cover surfaces of second resin particles containing a second resin
Data Source
AI summary
Toner particles contained in a liquid developer have a core-shell structure that first resin particles containing a first resin are attached to or cover surfaces of second resin particles containing a second resin. The second resin satisfies Equations (1) to (2) below. In Equations (1) to (2) below, x represents a number average molecular weight of the second resin and y represents a urethane group concentration (mass %) in the second resin.−0.00003x+2.03≦y≦−0.00003x+6.95 Equation (1)10000≦x≦50000 Equation (2)