Printing Apparatus Density Correction via Target Offset
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Solution Overview
Problem
Existing printing technologies face challenges in achieving uniform printing density, leading to grainy results due to variations in dot size and position, which affect the quality of the printed image.
Innovation Solution
A printing apparatus and method that calculates a target density by averaging pre-correction printing density and adjusts the correction gain for each printing element based on the ratio of target to pre-correction density, ensuring the target density is equal to or greater than the pre-correction density, thereby controlling the printer to produce a less grainy output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If correction gain is calculated based on ratio of target density to pre-correction printing density, then printing density uniformity is improved, but graininess increases when correction gain reduces dot size
Solution Approach 1:
The patent applies preliminary anti-action by offsetting the target density upward before calculating correction gain. This pre-compensates for the potential reduction in dot size that would cause graininess, ensuring that even after correction, the printed dots maintain sufficient size while achieving density uniformity across different printing elements
Solution Approach 2:
The patent changes the target density parameter by applying an upward offset based on the standard deviation of pre-correction printing densities. This parameter modification ensures that the correction process achieves uniformity without excessive dot size reduction, thereby preventing graininess while maintaining density consistency
2Manufacturing precision
If dot size is reduced to correct printing density variations, then density uniformity improves, but image quality deteriorates due to grainy appearance
Solution Approach 1:
The patent preemptively offsets the target density upward to counteract the potential harmful effect of dot size reduction. This ensures that correction is achieved while maintaining adequate dot size for image quality, preventing the grainy appearance that would otherwise result from excessive dot size reduction
Solution Approach 2:
The patent converts the potential harm of dot size reduction into a benefit by using the offset mechanism. The upward offset ensures that even when correction gain reduces dot size, the resulting dots remain large enough to maintain image quality, transforming what would be a harmful effect into an acceptable outcome that achieves both uniformity and quality
Data Source
AI summary
A printing apparatus includes a printer with printing elements that print dots and a controller that acquires input image data. The controller acquires a pre-correction printing density that is based on test pattern data, which includes a uniform array of pixels, and printing characteristics of printing positions of the dots printed by the plurality of printing elements. The controller calculates a target density by averaging the pre-correction printing density and offsets the target density so that the target density is equal to or greater than the pre-correction printing density. The controller calculates a correction gain of the plurality of printing elements on the basis of the ratio of the target density to the pre-correction printing density and controls the printer on the basis of the correction gain and the input image data.