Image Recording Head Defect Compensation via Adaptive Dot Sizing
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Solution Overview
Problem
Existing image recording methods struggle to effectively compensate for multiple defective recording elements in close proximity, leading to insufficient correction and visible density non-uniformities in the recorded image.
Innovation Solution
An image recording method that acquires defective recording element information, including position and distance between defective elements, and performs compensation using nearby normal recording elements, adjusting tone values and dot sizes to suppress excessive compensation and achieve uniform density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If compensation is performed using peripheral recording elements for defective recording elements, then density non-uniformities are corrected, but excessive compensation occurs when multiple defective elements are in close proximity, causing visible dark lines
Solution Approach 1:
The patent applies local quality by differentiating compensation strategies based on the spatial distribution of defective recording elements. When multiple defective elements are detected in close proximity, the compensation parameters are locally adjusted to prevent excessive compensation. This is achieved by calculating the distance between defective elements and applying different compensation coefficients accordingly, thereby eliminating visible dark lines while maintaining density uniformity in other regions.
Solution Approach 2:
The patent implements dynamics by making the compensation parameters adaptive rather than static. The compensation system dynamically adjusts the compensation amount based on the detected pattern of defective elements. When defective elements are closely spaced, the system reduces compensation to avoid artifacts; when they are isolated, full compensation is applied. This dynamic adjustment resolves the contradiction between achieving uniformity and avoiding excessive compensation artifacts.
2Device complexity
If multiple defective recording elements are compensated using the same method as isolated defective elements, then compensation is simplified, but insufficient correction occurs leading to visible density non-uniformities
Solution Approach 1:
The patent applies segmentation by dividing the compensation process into distinct cases based on the spatial relationship between defective elements. The system segments defective element patterns into categories (isolated vs. closely spaced) and applies different compensation algorithms to each segment. This segmentation maintains relative simplicity while achieving precise correction for each case, resolving the contradiction between method simplicity and correction effectiveness.
Solution Approach 2:
The patent implements parameter changes by modifying compensation coefficients based on the detected configuration of defective elements. The system changes key parameters such as compensation amount and distribution pattern according to whether defective elements are isolated or clustered. This parameter adaptation enables effective correction for multiple defective elements without requiring a completely different compensation methodology, thus maintaining simplicity while improving precision.
3Productivity
If recording elements are arranged in a two-dimensional configuration for single-pass image recording, then productivity is improved, but defective elements cause stripe-shaped density non-uniformities that dramatically reduce image quality
Solution Approach 1:
The patent applies preliminary action by detecting and mapping defective recording elements before actual image recording occurs. The system performs a preliminary scan or uses pre-stored defect information to identify all defective elements and their positions. Based on this preliminary information, compensation parameters are pre-calculated and stored. When recording, the system simply applies these pre-computed parameters, thereby maintaining high productivity while ensuring image quality correction without requiring complex real-time adjustments.
Solution Approach 2:
The patent implements feedback by using detected defective element information to adjust compensation parameters. The system establishes a feedback loop where defective element detection results directly inform the compensation strategy. This feedback mechanism enables the system to automatically adapt to the actual head conditions, correcting stripe-shaped density non-uniformities caused by defective elements while maintaining the efficiency of single-pass recording.
Data Source
AI summary
An image recording method of recording a desired image on a recording medium by a recording head having recording elements which form pixels on the recording medium, while moving at least one of the recording medium and the recording head relatively to each other in a prescribed conveyance direction, the method includes: a defective recording element information acquisition step of acquiring defective recording element information including position information of defective recording elements included in the recording elements; and a defective recording element compensation step of performing compensation for the defective recording elements by using compensation recording elements in accordance with a distance between a pair of the defective recording elements derived from the position information, the compensation recording elements being of normal recording elements included in the recording elements situated nearby the pair of the defective recording elements.