Fixing Metallic Sheets with Low Thermal Conductivity Toner
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Solution Overview
Problem
The electrophotographic image forming method on metallic sheets faces challenges with adhesion between the metallic sheet and the toner layer, particularly in small-volume printing, where the existing methods result in poor image quality and separation of the toner layer due to inadequate heat transfer at the interface.
Innovation Solution
The method involves transferring white toner and color toner onto a metallic sheet with a thermal conductivity of 0.34 W/m·K or less, followed by fixing between a heated fixing rotator and a pressure rotator, ensuring sufficient adhesion by maintaining a lower interface temperature through reduced heat diffusion within the sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrophotographic image forming method is used on metallic sheets, then small-volume printing is enabled, but adhesion between toner layer and metallic sheet deteriorates due to heat diffusion
Solution Approach 1:
The patent changes the thermal parameter of the metallic sheet by selecting materials with specific thermal conductivity (0.34 W/m·K or less). This parameter change reduces heat diffusion during the fixing process, preventing toner layer separation while maintaining the ability to perform small-volume printing through electrophotographic methods.
Solution Approach 2:
The patent applies local quality by creating a specific thermal environment at the interface between the toner layer and metallic sheet. By controlling the thermal conductivity of the metallic sheet, the heat distribution is optimized locally at the critical interface region, ensuring sufficient adhesion without compromising the overall printing capability.
2Illumination intensity
If white layer is placed under the image to prevent darkening, then image impact is improved, but device complexity increases due to need for additional white toner capability
Solution Approach 1:
The patent utilizes the parameter change of using white toner in addition to the four color toners (cyan, magenta, yellow, and black) in the electrophotographic image forming apparatus. This allows the formation of a white layer under the image to prevent darkening and maintain image impact, while leveraging existing technological developments to minimize the increase in device complexity.
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 enhances adhesion between the toner layer and the metallic sheet, resulting in high-quality images without discoloration or deformation, suitable for small-volume printing on metallic sheets.
Implementation Method 1
conveying the metallic sheet, with the surface on which the white toner layer and the color toner layer are transferred facing the fixing rotator, between the fixing rotator heated and the pressure rotator to fix the white toner layer and the color toner layer onto the metallic sheet
Implementation Method 2
transferring white toner and color toner onto a surface of a metallic sheet having a thermal conductivity of 0.34 W/m·K or less as measured by hot-wire method
Data Source
AI summary
An image forming method for an image forming apparatus having a fixing rotator and a pressure rotator opposite the fixing rotator includes transferring white toner and color toner onto a surface of a metallic sheet. The metallic sheet has a thermal conductivity of 0.34 W/m·K or less as measured by hot-wire method. The transferring process forms an unfixed color toner layer layered on an unfixed white toner layer on the metallic sheet. Further, the method includes conveying the metallic sheet, with the surface on which the white toner layer and the color toner layer being transferred facing the fixing rotator, between the fixing rotator heated and the pressure rotator to fix the white toner layer and the color toner layer onto the metallic sheet.