Image Forming Method Using Clear Toner Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming methods using electrophotographic systems face challenges in preventing moire interference and achieving sufficient color saturation and gloss, particularly due to difficulties in controlling clear toner adhesion and the precision required for screen patterns with high line counts.
Innovation Solution
An image forming method that superimposes a color toner image and a clear toner image on an image support, with the clear toner image controlled based on the amount of color toner per unit area, using screen processing for the color toner and contone processing for the clear toner, and employing specific toner amounts and diameters to prevent excessive clear toner deposition and ensure sufficient gloss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a clear toner image is formed using screen processing with high line count to achieve smooth gloss, then image gloss is improved, but moire interference occurs and image quality degrades
Solution Approach 1:
The invention divides the gloss control function into two separate toner layers: color toner for image content and clear toner for gloss enhancement. This segmentation allows each layer to perform its specific function without causing moire interference, as the clear toner is applied independently of the screen processing used for color toner.
Solution Approach 2:
The clear toner acts as an intermediary layer between the color toner image and the final output medium. By placing this transparent gloss-providing layer on top of the color image, the invention achieves smooth gloss without requiring high-line-count screen processing, thereby avoiding moire effects.
2Shape
If clear toner amount is increased to enhance gloss, then image gloss is improved, but color saturation decreases due to excessive clear toner deposition
Solution Approach 1:
The invention changes the parameter of clear toner amount from a fixed value to a variable that depends on the color toner amount. Specifically, the clear toner amount is set to be inversely proportional to the color toner amount per unit area, ensuring optimal gloss while maintaining color saturation across different image regions.
Solution Approach 2:
The invention applies different amounts of clear toner to different regions based on the local color toner density. Regions with less color toner receive more clear toner for gloss enhancement, while regions with more color toner receive less clear toner to preserve color saturation. This local optimization prevents the trade-off between gloss and color saturation.
3Manufacturing precision
If screen processing with high line count is used to prevent moire, then image resolution is improved, but manufacturing complexity increases due to precise laser beam control requirements
Solution Approach 1:
The invention extracts the gloss-providing function from the screen processing step and implements it through a separate clear toner application step. This removes the need for high-line-count screen processing and its associated precise laser beam control requirements, while still achieving the desired image quality and gloss.
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 method effectively prevents moire interference and achieves sufficient color saturation and gloss by controlling the clear toner deposition relative to the color toner, ensuring a smooth and glossy image output.
Implementation Method 1
employing an electrophotographic system to form a stacked toner image which has a color toner image of a color toner and a clear toner image of a clear toner superimposed one on another
Data Source
AI summary
An image forming method which is capable of preventing occurrence of moire and forming images having sufficient color saturation and a sufficient gloss is provided. The color toner image is formed in accordance with a color image signal obtained through screen processing using a screen pattern having a screen line count of 50 to 270 lpi on manuscript image data, and the clear toner image is formed in accordance with a clear image signal obtained through contone processing on the manuscript image data. The clear image signal is controlled so that, according to the amount of the color toner per unit area of the stacked toner image obtained by the color toner image being superimposed with the clear toner image, the less the amount of the color toner, the more the amount of the clear toner becomes.