Ink-jet Printer Nozzle Overlap Control for Streak Reduction
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Solution Overview
Problem
Ink-jet printers face issues with non-uniform shading due to deviations in transported length, leading to white or black streaks between image parts printed in successive passes, which can be conspicuous and lower image quality, and existing methods to mitigate this often result in longer printing times by increasing the number of passes.
Innovation Solution
The printer employs a controller to manage nozzle groups with overlapping scanning areas and sets usable bordering positions based on printing duty or nozzle type, allowing for deliberate misalignment of nozzle positions to reduce streaks, while optimizing the number of passes based on necessary suppression of non-uniform shading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the scanning area of previous pass and successive pass are made to overlap partially in transport direction, then non-uniform shading (streaks) is suppressed, but the number of passes increases and printing time becomes longer
Solution Approach 1:
The patent applies local quality by differentiating the treatment of different regions in the image. The overlapping range between passes is specifically targeted to suppress non-uniform shading, while other regions are printed normally. This localized approach to quality enhancement prevents streaks only where necessary (at pass boundaries) without requiring increased overlap that would slow down overall printing.
2Manufacturing precision
If the border between image parts from previous and successive passes is zigzag changed, then non-uniform shading is suppressed, but device complexity and control complexity increase
Solution Approach 1:
The patent implements dynamics by making the border position adaptive rather than fixed. The border between image parts from previous and successive passes is dynamically adjusted (zigzag changed) based on the actual transport position detection. This dynamic border adjustment suppresses non-uniform shading while maintaining relatively simple control logic, as the complexity is limited to detecting transport position and shifting the border accordingly.
3Manufacturing precision
If multicolor printing is performed with each border misaligned between nozzle rows for different colors, then streaks become less conspicuous, but the overlapping range must be larger and printing time increases
Solution Approach 1:
The patent applies asymmetry by intentionally misaligning the borders for different color nozzle rows in the overlapping range. Instead of symmetric alignment, each color's border is shifted differently to create an asymmetric pattern that disperses the visual impact of streaks. This asymmetric border arrangement for multicolor printing suppresses conspicuous streaks while controlling the overlap range to minimize printing time increase.
Data Source
AI summary
There is provided an ink-jet printer including an ink-jet head, a conveyance section, and a controller. The ink-jet head includes a plurality of nozzle groups. Between the plurality of nozzle groups, the nozzles forming the nozzle groups are positioned in conformity with each other, respectively, in a second direction. The controller causes the conveyance section to convey the recording medium between a first pass and a second pass such that the respective nozzle groups have partly overlapped scanning areas, and causes the ink-jet head to print separately between the first pass and the second pass in the second direction. The controller sets usable bordering positions in the overlapping range with respect to the passes. The controller sets the usable bordering positions based on one of such conditions as a duty of printing on the recording medium and a type of the nozzle groups to be used in printing.