Inkjet Head Nozzle Scanning for Banding Reduction
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Solution Overview
Problem
Ink jet printers face a decline in printing speed due to the need to adjust transport amounts based on varying scanning frequencies across different printing areas, leading to banding issues and reduced image quality.
Innovation Solution
An image forming apparatus with a head having multiple nozzles that scans in the main direction and transports media in the sub-scanning direction, where the number of scans for areas with nozzles is increased to form dot arrays, allowing for quantitative transport and reduced banding by alternating scanning and transport operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of scanning times is increased for areas with nozzles to reduce banding, then image quality is improved, but printing speed is deteriorated
Solution Approach 1:
The patent applies local quality by differentiating the number of scanning times based on the nozzle distribution pattern. Areas with nozzles (principle portion) are scanned more times (e.g., 3 times) to reduce banding, while areas without nozzles (non-principle portion) are scanned fewer times (e.g., 1 time). This localized differentiation improves image quality in critical areas without uniformly reducing printing speed across the entire medium.
2Manufacturing precision
If the transport amount is adjusted based on varying scanning frequencies, then banding is reduced, but the printing process complexity increases
Solution Approach 1:
The patent segments the medium into multiple regions based on nozzle distribution patterns (principle portions and non-principle portions). Each segment is assigned a different number of scanning times, allowing independent optimization of banding reduction for each segment. This segmentation simplifies the control logic compared to continuously adjusting transport amounts, as the medium is divided into discrete regions with fixed scanning parameters.
3Manufacturing precision
If the number of passes is increased for certain areas, then dot array formation is improved, but the overall printing time increases
Solution Approach 1:
The patent applies local quality by increasing the number of scanning passes only in specific regions (principle portions) where nozzles are located and dot array formation is critical. Non-principle portions are processed with fewer passes, thereby reducing the overall printing time while maintaining high-quality dot array formation in the principle portions where it matters most.
Data Source
AI summary
In an image forming apparatus (an ink jet printer 100), in a sub scanning direction, when an area in arrange of a nozzle at an end portion of a head (41) to a nozzle at a predetermined distance is set as a predetermined area, and a medium is transported in a certain amount by using the head (41), a scan portion, and a transport portion so as to form an image on medium sheet (10), the number of times of scanning for forming a dot array which is formed by using the nozzles included in the predetermined area is more than the number of times of the scanning for forming a dot array which does not use the nozzle in the predetermined area, and the number of times of the scanning for forming the dot array by using the nozzles included in the predetermined area is at least three times.