Zigzag Recording Head Controller for Banding Reduction
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Solution Overview
Problem
In recording apparatuses with multiple heads disposed in zigzag, the full-overlap method often results in banding unevenness due to misalignment of heads, leading to inconsistent spacing between raster lines, which affects print quality.
Innovation Solution
A recording apparatus with a controller that determines the use of each recording head based on image data to ensure all raster lines are formed using heads parallel to the main scanning direction, maintaining consistent spacing and preventing banding unevenness, even when the recording unit is inclined.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple recording heads are disposed in zigzag to increase printing width, then productivity is improved, but manufacturing precision deteriorates due to banding unevenness
Solution Approach 1:
The patent divides the recording heads into multiple groups (first through fourth groups) based on their positional relationships in the sub-scanning direction. Each group is assigned to form specific raster lines, ensuring that heads within the same group maintain consistent spacing relationships. This segmentation prevents banding unevenness by ensuring uniform spacing between raster lines formed by different head groups.
Solution Approach 2:
The patent applies different recording head selection strategies for different raster lines based on local positional characteristics. By determining which recording heads form dots for each specific raster line according to their relative positions, the system maintains consistent spacing uniformity locally while achieving overall wide printing coverage through multiple heads.
2Device complexity
If recording heads are positioned with shifts in sub-scanning direction to enable zigzag arrangement, then device complexity is reduced, but manufacturing precision deteriorates due to head misalignment
Solution Approach 1:
The patent changes the parameter of head group assignment based on the positional relationships of recording heads. By categorizing heads into different groups according to their sub-scanning direction positions and assigning specific groups to form specific raster lines, the system maintains consistent spacing even when heads are shifted in the sub-scanning direction, thus preserving manufacturing precision without increasing device complexity.
3Manufacturing precision
If full-overlap method is used to form dots by multiple main scanning passes, then manufacturing precision is improved, but productivity deteriorates due to increased processing time
Solution Approach 1:
The patent performs preliminary classification of recording heads into multiple groups based on their positional relationships before the actual printing process. By pre-determining which head groups form which raster lines and establishing consistent spacing relationships in advance, the system achieves both high dot formation accuracy and improved printing speed, as the head selection logic is predetermined rather than calculated in real-time during printing.
Data Source
AI summary
A full-overlap type recording apparatus includes a recording unit and a controller. In the recording unit, n pieces of recording heads are disposed in a main scanning direction, positions of the n pieces of recording heads are shifted from each other in a sub-scanning direction, and the n pieces of recording heads are disposed so as to form m sets in the sub-scanning direction. The controller determines a use head based on the image data, and the use head is a recording head used for forming dots on a recording medium. The controller determines the use head for all raster lines formed on the recording medium, so as to respectively use the n pieces of recording heads when the raster lines are formed.