Electrostatic Developing Toner Viscoelasticity for Uniform Image Gloss
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Solution Overview
Problem
Existing electrostatic charge image developing toners exhibit varying glossiness between regions of high and low toner application, leading to gloss unevenness in fixed images, particularly on smooth surfaces.
Innovation Solution
The toner particles are formulated to satisfy specific viscoelasticity criteria, including storage modulus values at different temperatures and strains, incorporating specific resin particles with high elastic modulus to stabilize toner deformation and reduce gloss variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If toner particles are formulated to readily melt by heating to obtain excellent fixability, then fixability is improved, but glossiness varies between regions of high and low toner application leading to gloss unevenness
Solution Approach 1:
The invention changes the viscoelasticity parameters of the binder resin by controlling the molecular weight distribution (specifically making the weight average molecular weight 10,000 or more times the number average molecular weight) and incorporating specific resin particles. This parameter change allows the toner to maintain appropriate deformation characteristics during fixing, achieving both excellent fixability and uniform gloss appearance across regions with varying toner application amounts.
Solution Approach 2:
The invention uses a composite binder resin system consisting of multiple resin components with different molecular weights and specific resin particles. This composite structure combines the benefits of low molecular weight resins (which melt readily for good fixability) with high molecular weight resins (which maintain structural integrity for uniform gloss), resolving the contradiction between fixability and gloss uniformity.
2Reliability
If toner particles melt readily by heating, then fixability is improved, but deformation control becomes difficult leading to gloss differences in low and high application regions
Solution Approach 1:
The invention optimizes the viscoelasticity parameters of the binder resin by controlling molecular weight distribution and incorporating resin particles with specific elastic moduli. This allows precise control of toner deformation during the fixing process, ensuring uniform gloss appearance while maintaining excellent adhesion to the recording medium.
Solution Approach 2:
The invention introduces resin particles with high elastic modulus as intermediary elements within the binder resin matrix. These particles act as structural supporters that control deformation behavior during fixing, mediating between the need for rapid melting (for fixability) and controlled deformation (for gloss uniformity).
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 formulation achieves improved fixability and minimizes gloss differences between regions of varying toner application, resulting in more uniform image gloss across the image surface.
Implementation Method 1
the binder resin contains at least a crystalline resin, and a storage modulus of the toner measured at a frequency of 1 Hz, 150° C., and a strain varied in a range of 0.01% to 1,000% satisfies a specific relationship
Data Source
AI summary
An electrostatic charge image developing toner contains toner particles that contain a binder resin, in which in a case where G′1 (90) represents a storage modulus G′ of the electrostatic charge image developing toner determined by measuring dynamic viscoelasticity of the electrostatic charge image developing toner at a temperature of 90° C. and a strain of 1%, G′50 (90) represents a storage modulus G′ of the electrostatic charge image developing toner determined by measuring dynamic viscoelasticity of the electrostatic charge image developing toner at a temperature of 90° C. and a strain of 50%, and G′50 (180) represents a storage modulus G′ of the electrostatic charge image developing toner determined by measuring dynamic viscoelasticity of the electrostatic charge image developing toner at a temperature of 180° C. and a strain of 50%, the electrostatic charge image developing toner satisfies the following Formulas (1) to (4).G′1(90)<1×105 Formula (1)1×103<G′50(180) Formula (2)1<G′50(90)/G′50(180)<30 Formula (3)1<G′1(90)/G′50(90)<10 Formula (4)