Dual Print Engine Toner Diameter Control for Shade Uniformity
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Solution Overview
Problem
In color electrophotographic printers, the mixing of white toner with other color toners can impair image quality due to differences in toner particle diameters, leading to uneven shade and surface issues on the recording medium.
Innovation Solution
The use of a first print engine forming a white toner image with a smaller average particle diameter than a second color toner image, ensuring the white toner layer covers the recording medium effectively and prevents unwanted mixing, with the white toner having an average diameter not larger than 0.95 times that of the color toner, typically between 6.0 μm and 6.7 μm, to minimize color shade changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If white toner is used to hide the color of the recording medium, then the recording medium color is concealed, but color toner mixed with white toner impairs image quality
Solution Approach 1:
The patent applies parameter changes by carefully controlling the average particle diameter of the white toner to be within a specific range (6.0 μm to 6.7 μm) and ensuring it is not larger than 0.95 times the average diameter of the color toner. This parameter optimization prevents excessive mixing between white and color toners while maintaining effective color concealment, thereby resolving the contradiction between ease of manufacture and image quality.
2Area of stationary object
If white toner with larger average particle diameter is used, then coverage is improved, but color shade variation increases due to toner mixing
Solution Approach 1:
The patent resolves this contradiction by optimizing the particle diameter parameter of white toner to a specific range (6.0 μm to 6.7 μm) and establishing the relationship that white toner average diameter should not exceed 0.95 times the color toner average diameter. This controlled parameter selection ensures adequate coverage while minimizing color shade variations caused by toner mixing.
3Manufacturing precision
If white toner with smaller average particle diameter is used, then toner mixing is reduced, but coverage effectiveness decreases
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal particle diameter range for white toner (6.0 μm to 6.7 μm) that balances two opposing requirements: small enough to prevent excessive mixing with color toner, yet large enough to maintain effective coverage. The additional constraint that white toner diameter ≤ 0.95 × color toner diameter further refines this balance.
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 ensures a uniform transfer of color toners onto the white toner layer, reducing color shade variations and maintaining image quality by minimizing the mixture of toners, thus achieving a desired shade and smooth surface.
Implementation Method 1
a first print engine that forms a first image formed of a first toner
Implementation Method 2
a second print engine that forms a second image formed of a second toner and transfers the second image onto the first image in registration
Data Source
AI summary
An image forming apparatus includes a first print engine and a second print engine. The first print engine forms a first image formed of a first toner having a first average diameter. The first image is transferred onto a recording medium. The second print engine forms a second image formed of a second toner having a second average diameter larger than the first average diameter. The second image is transferred onto the first image in registration.