Toner Crystalline Material Distribution for Image Uniformity
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Solution Overview
Problem
Existing toners experience image unevenness when used on media with large irregularities due to differences in plasticization of the toner by a crystalline material between protruding and recessed portions.
Innovation Solution
A toner with a specific composition and surface treatment, where the ratio of the area occupied by the crystalline material on the toner surface is controlled to achieve both low-temperature fixability and reduced image unevenness on irregular media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a crystalline material is used in the toner to achieve low-temperature fixability, then the fixability at low temperature is improved, but image unevenness occurs on media with large irregularities due to significant differences in plasticization between protruding and recessed portions
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of crystalline material within the toner particle. Specifically, the crystalline material is concentrated in the internal region while the surface region contains minimal crystalline material. This local differentiation allows the interior to provide low-temperature fixability while the surface maintains uniform plasticization characteristics that prevent image unevenness on irregular media.
Solution Approach 2:
The patent changes the spatial distribution parameter of the crystalline material within the toner particle. By controlling the crystalline material to be located primarily in the internal region rather than uniformly distributed or surface-concentrated, the patent modifies the plasticization behavior across different regions of the toner particle, thereby resolving the contradiction between low-temperature fixability and image uniformity.
2Temperature
If the crystalline material is placed closer to the toner surface to improve low-temperature fixability, then the fixability is enhanced, but image unevenness occurs on irregular media
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of crystalline material within the toner particle. Specifically, the crystalline material is concentrated in the internal region while the surface region contains minimal crystalline material. This local differentiation allows the interior to provide low-temperature fixability while the surface maintains uniform plasticization characteristics that prevent image unevenness on irregular media.
Solution Approach 2:
The patent inverts the conventional approach by placing the crystalline material in the internal region rather than near the surface. This inversion of the expected spatial arrangement allows the toner to achieve low-temperature fixability through the internal crystalline material while avoiding the image unevenness that would result from surface-proximal crystalline material on irregular media.
3Reliability
If a shell layer with thermosetting resin is added to improve color developability and stability, then color developability and heat-resistant storage stability are improved, but the toner still experiences image unevenness on irregular media
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of crystalline material within the toner particle. Specifically, the crystalline material is concentrated in the internal region while the surface region contains minimal crystalline material. This local differentiation allows the interior to provide low-temperature fixability while the surface maintains uniform plasticization characteristics that prevent image unevenness on irregular media.
Solution Approach 2:
The patent employs composite materials by combining a shell layer containing thermosetting resin with an internal region containing crystalline material. This composite structure integrates the benefits of the shell layer (color developability, heat-resistant storage stability, charging stability) with the optimized internal crystalline material distribution (low-temperature fixability without image unevenness), thereby achieving multiple performance improvements simultaneously.
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 low-temperature fixability and significantly reduces image unevenness on media with large irregularities by controlling the distribution and amount of crystalline material on the toner surface.
Implementation Method 1
treating the toner in a ruthenium tetroxide (RuO4) gas atmosphere at 100 Pa for 5 minutes
Data Source
AI summary
The toner is a toner including a toner particle comprising a binder resin, a crystalline material, wherein, when a ratio of an area occupied by the crystalline material in a toner surface observed with a scanning electron microscope after ruthenium-staining the toner under a specific condition (1) is represented by S1 (%), a ratio of an area occupied by the crystalline material in the toner surface observed with the scanning electron microscope after ruthenium-staining the toner under a condition (2) is represented by S2 (%), and a dispersion diameter of a plurality of domains formed of the crystalline material on the toner surface observed with the scanning electron microscope after the ruthenium-staining the toner under the condition (2) is represented by R2 (nm), the following expressions (1), (2), and (3) are satisfied.0.0≤S1≤0.5(1)1.≤S2≤10.(2)20≤R2≤200(3)