Full Color Toner Melt Viscosity Profile for Fixing
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Solution Overview
Problem
Existing full-color image forming processes in electrophotographic systems face challenges in balancing low-temperature fixing ability with hot offset resistance when using black, cyan, magenta, and yellow toners, as toners excellent in one tend to compromise the other.
Innovation Solution
The process involves using toners with specific apparent viscosities and melt viscosity profiles, where the outermost layer toner has a maximum or shoulder peak between 105° C. and 130° C., and inner layer toners lack such peaks, optimizing the toner arrangement on the transfer medium to achieve balanced low-temperature fixing and hot offset resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If toners excellent in low-temperature fixing ability are used, then fixing temperature is reduced, but hot offset resistance deteriorates
Solution Approach 1:
The invention applies local quality by differentiating the melt viscosity characteristics of toners based on their position in the color layer structure. Outer layer toners (yellow, cyan, magenta) have a maximum or shoulder peak in melt viscosity between 105°C and 130°C to ensure low-temperature fixing, while inner layer black toner lacks such peak to maintain hot offset resistance. This localized differentiation of material properties resolves the contradiction between low-temperature fixing and hot offset resistance.
Solution Approach 2:
The invention segments the full-color toner system into distinct groups based on their melt viscosity profiles: outer layer toners (yellow, cyan, magenta) with peak viscosity between 105-130°C, and inner layer black toner without such peak. This segmentation allows each group to fulfill its specific functional requirement - outer layers provide low-temperature fixing while inner layer provides hot offset resistance - thereby resolving the technical contradiction.
2Ease of manufacture
If multiple color toners are superimposed to form full-color image, then color reproduction is achieved, but hot offset tendency increases
Solution Approach 1:
The invention applies local quality by assigning different melt viscosity characteristics to toners based on their positional function in the color layer. Outer layer toners (yellow, cyan, magenta) possess a maximum or shoulder peak in melt viscosity between 105°C and 130°C, enabling low-temperature fixing that reduces hot offset. The inner layer black toner lacks such peak, providing thermal stability. This localized differentiation allows full-color image formation while mitigating hot offset caused by superimposition.
3Temperature
If toners with specific melt viscosity peaks are used for low-temperature fixing, then fixing temperature is lowered, but storage stability may deteriorate
Solution Approach 1:
The invention segments the toner population into two functional groups: outer layer toners (yellow, cyan, magenta) with melt viscosity peak between 105-130°C for low-temperature fixing, and inner layer black toner without such peak for storage stability and hot offset resistance. This segmentation ensures that the potential storage stability issues associated with low-temperature fixing toners are isolated to outer layers, while the heat-resistant black toner in the inner layer provides overall system stability.
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 approach enables the formation of full-color images with enhanced low-temperature fixing ability and hot offset resistance, preventing both low storage stability and hot offset issues.
Implementation Method 1
When the binder resin of the colored polymer particles, which will become core particles is formed by a polymer having a relatively low glass transition temperature, and the polymer layer, which will become a shell, is formed by a polymer having a relatively high glass transition temperature, a polymerized toner well balanced between low-temperature fixing ability and storage stability (blocking resistance) can be obtained.
Implementation Method 2
a toner, in which a maximum peak or a shoulder peak is present between 105° C. and 130° C. in a temperature-logarithmic melt viscosity graph
Data Source
AI summary
A process for forming a full-color image, wherein the 4 color toners each have an apparent viscosity at 105° C. of 50,000 to 300,000 Pa·s and an apparent viscosity at 130° C. of 3,000 to 30,000 Pa·s, and as a color toner arranged at the outermost layer on a transfer medium among the 4 color toners, a toner, in which a maximum peak or a shoulder peak is present between 105° C. and 130° C. in a temperature-logarithmic melt viscosity graph, is used, and as the other color toners arranged at lower layers than the outermost layer, toners, in which neither the maximum peak nor the shoulder peak is present between 105° C. and 130° C., are used.