Compensatory Toner Layer for Foil-Printed Image Step Reduction
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Solution Overview
Problem
Image forming apparatuses struggle to suppress the formation of image steps in foil-printed images, as the existing methods fail to uniformly superpose a second toner layer and a foil layer, leading to noticeable height variations.
Innovation Solution
The apparatus includes a first toner layer forming unit, a foil layer forming unit, and a second toner layer forming unit, where the second toner layer is positioned below the foil layer to compensate for image steps, using an adhesive toner with a lower melting point than the fundamental toner, and a foil layer is applied with a foil sheet having a base member, adhesive layer, and foil layer, which is heated and pressed to adhere only to areas with adhesive toner, thereby reducing height variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a second toner layer is uniformly superposed onto a first toner layer and then a foil layer is superposed on the upper layer, then the foil-printed image can be formed, but image steps are formed in the region of the foil-printed image due to height variations
Solution Approach 1:
The invention applies preliminary action by forming a compensatory toner layer before the foil layer to pre-compensate for height variations. The compensatory toner layer is formed with a thickness that compensates for the height variations of the first toner layer, ensuring that the surface is sufficiently flat before foil application, thereby preventing image steps in the final foil-printed image.
Solution Approach 2:
The invention applies local quality by making the compensatory toner layer's thickness non-uniform. The thickness is specifically designed to vary in different regions to match and compensate for the local height variations of the first toner layer. This localized adjustment ensures optimal surface flatness in each region without unnecessarily increasing overall device complexity.
2Reliability
If the foil layer is heated and pressed to adhere to the image, then the foil is transferred to the medium, but height variations in the first toner layer cause image steps in the foil-printed region
Solution Approach 1:
The compensatory toner layer is formed in advance before the foil layer is applied and heated. This preliminary compensation ensures that when the foil layer is subsequently heated and pressed, it adheres to a surface with minimized height variations, thereby preventing image steps while maintaining reliable adhesion through the heating and pressing process.
Solution Approach 2:
The compensatory toner layer acts as an intermediary between the first toner layer and the foil layer. It mediates the interface by providing a more uniform surface for foil adhesion, thereby eliminating the direct contact between the foil layer and the uneven first toner layer surface, which prevents image step formation while ensuring proper foil transfer.
3Manufacturing precision
If a compensatory toner layer is formed below the foil layer to compensate for image steps, then surface flatness is improved, but the device complexity increases due to additional forming units
Solution Approach 1:
The invention merges the compensatory toner layer formation function into the existing first image forming unit. The first image forming unit is configured to form both the first toner layer and the compensatory toner layer, eliminating the need for a separate dedicated compensating device. This integration achieves improved surface flatness while minimizing the increase in device complexity by utilizing existing components for multiple purposes.
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 configuration effectively reduces image steps in foil-printed images by compensating for height variations in the fundamental image, ensuring a smoother and more uniform finish, with the adhesive toner layer ensuring the foil layer adheres correctly, resulting in a more aesthetically pleasing and consistent image.
Implementation Method 1
heating the printing foil to a temperature that is higher than the melting temperature of the foil adhesive and lower than the melting temperature of the toner
Implementation Method 2
a foil layer forming unit that forms a foil layer on the first toner layer on a surface of the medium on which an image is to be formed
Data Source
AI summary
An image forming apparatus includes a first image forming unit that forms a first toner layer on a medium on which an image is to be formed, a foil layer forming unit that forms a foil layer on the first toner layer on a surface of the medium on which an image is to be formed, and a second image forming unit that forms a second toner layer below the foil layer on the surface of the medium, on which an image is to be formed, in such a manner as to compensate for image steps that are formed by the first toner layer.