Duplex Printing Ink Coverage Control via Black Generation
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Solution Overview
Problem
Existing image forming apparatuses fail to adequately control expansion and contraction of print sheets due to ink absorption, leading to insufficient registration accuracy in duplex printing.
Innovation Solution
An image forming apparatus that adjusts ink coverage, black generation ratio, and print timing to minimize sheet expansion and contraction by using a print condition adjustment unit, black-generation-and-UCR processing unit, and image outputting unit to optimize ink usage and printing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ink is ejected to the print sheet for image printing, then image quality is improved, but sheet expansion and contraction occur due to ink absorption
Solution Approach 1:
The patent changes the parameter of ink coverage ratio by dynamically adjusting the black generation ratio based on calculated ink coverage. When ink coverage exceeds a threshold, the system increases black generation ratio to replace excess chromatic ink, thereby controlling total ink application and preventing sheet expansion while maintaining image quality.
2Manufacturing precision
If black generation ratio is increased to reduce ink coverage, then sheet expansion and contraction are reduced, but image quality may deteriorate
Solution Approach 1:
The system dynamically adjusts the black generation ratio parameter based on calculated ink coverage values. By establishing a threshold-based adjustment mechanism, the system only increases black generation when ink coverage exceeds the threshold, thereby maintaining sheet dimensional stability while preserving image quality through selective parameter modification rather than blanket adjustment.
3Manufacturing precision
If ink coverage is reduced to control sheet expansion, then registration accuracy improves, but image density and quality may be compromised
Solution Approach 1:
The patent employs parameter change by adjusting the black generation ratio in response to ink coverage calculations. When ink coverage is high, the system increases black generation to replace chromatic ink, thereby reducing total ink coverage to control sheet expansion while maintaining image density through the substitutive effect of black ink generation.
Solution Approach 2:
The system converts the potentially harmful effect of high ink coverage (sheet expansion) into a benefit by using black generation to replace excess chromatic ink. This substitution reduces total ink coverage and prevents sheet distortion while maintaining or even enhancing image quality through the added black component.
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
Reduces sheet expansion and contraction, maintaining image quality and improving registration accuracy in duplex printing.
Implementation Method 1
an inkjet printing device configured to eject ink to a print sheet and thereby print an image
Implementation Method 2
expansion and contraction of a print sheet due to drying
Data Source
AI summary
A black-generation-and-UCR processing unit generates image data of a black ink color from image data of chromatic ink colors of the image and adjusts values of the image data of the chromatic ink colors correspondingly to generation of the image data of the black ink color. An image outputting unit causes a printing device to perform printing based on the image data. A print condition adjustment unit derives an ink coverage of the image on a print sheet, determines a black generation ratio corresponding to the ink coverage, and causes the black-generation-and-UCR processing unit to perform generation of the image data of the black ink color with the determined black generation ratio. The ink coverage indicates a ratio of ink usage amounts of the chromatic ink colors and the black ink color to a predetermined maximum value, for a pixel for which ink is ejected in the image.