Toner Layering for Dust Control and Hot Offset
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Solution Overview
Problem
Electrophotographic devices face challenges in reducing dust emission and maintaining high gloss in graphic printing, where hot offset resistance is poor due to high toner adherence and wax melting, leading to image degradation and increased dust emission.
Innovation Solution
An image forming method using at least four color toners with controlled dust emission levels, where the outermost layer contains hydrocarbon wax and the lowermost layer contains microcrystalline or ester wax, maintaining a specific dust emission ratio to optimize hot offset resistance and gloss retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wax with good releasability (non-polar, low molecular weight) is used to improve release effect during fixation, then fixation performance is improved, but dust emission increases due to sublimation
Solution Approach 1:
The patent applies local quality by using different types of waxes in different toner layers. The outermost layer uses non-polar wax (paraffin or microcrystalline) for good releasability, while the lowermost layer uses polar wax (ester or polyol ester) for low dust emission. This spatial differentiation allows each layer to perform its specific function optimally.
Solution Approach 2:
The patent uses composite materials by combining different wax types in a multi-layer toner structure. The outermost layer contains non-polar wax for release, while the lowermost layer contains polar wax for dust suppression. This composite approach integrates the advantages of both wax types to resolve the contradiction between releasability and dust emission.
2Manufacturing precision
If high toner adherence is used for graphic printing to improve image quality and gloss, then image quality is improved, but hot offset resistance deteriorates due to wax melting
Solution Approach 1:
The patent applies local quality by assigning different wax characteristics to different layers. The outermost layer uses non-polar wax with good releasability to prevent hot offset, while the lowermost layer uses polar wax with high adhesion to ensure image quality and gloss. This layered approach allows simultaneous optimization of both image quality and hot offset resistance.
Solution Approach 2:
The patent segments the toner into multiple layers with different functions. The outermost layer is segmented to provide release properties, while the lowermost layer is segmented to provide adhesion properties. This segmentation allows the system to handle both high toner adherence requirements and hot offset resistance requirements independently.
3Reliability
If non-polar wax is used to improve releasability, then release effect is improved, but intermolecular force with binder resin decreases leading to increased sublimation
Solution Approach 1:
The patent applies local quality by placing non-polar wax only in the outermost layer where releasability is needed, while placing polar wax in the lowermost layer where stability is needed. This spatial separation allows each wax type to perform its optimal function without compromising the other.
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 method effectively reduces dust emission and improves hot offset resistance while maintaining high gloss in graphic printing, balancing toner adherence and environmental performance.
Implementation Method 1
the wax in the toner not only melts to exhibit a release effect
Implementation Method 2
Dust is a result of the physical sublimation phenomenon of the wax components
Implementation Method 3
those having polarity such as ester wax and the like, or high-molecular-weight waxes, and further those having a high content of unnormalized forms such as iso-form, cyclic form and the like of hydrocarbon waxes hardly bleed out during fixation owing to the above-mentioned intermolecular force
Implementation Method 4
a fixation step of fixing a toner image on a recording medium using a fixing unit
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to an image forming method and an image forming device using at least four color toners of yellow, magenta, cyan and black, and having a fixation step of fixing a toner image on a recording medium using a fixing unit, wherein the total of a dust emission amount from each toner is controlled to be not more than a specific level, and wherein just before the fixation step where the three color toners of yellow, magenta and cyan are laminated on the recording medium, a dust emission amount from the toner to be the outermost layer on the recording medium and a dust emission amount from the toner to be the lowermost layer thereon are controlled to be in a specific relationship therebetween.