Inkjet Print Region Overlap Control for Banding Suppression
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Solution Overview
Problem
Ink jet printers face issues with banding, which occurs due to transport errors and differences in ink droplet granularity between link and non-link portions, affecting image density and printing speed.
Innovation Solution
A printing control device and method that adjusts the overlap between print regions by changing the sub-scanning distance based on record density, ensuring partial overlap or non-overlap to suppress banding and improve printing speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If partial overlap printing is performed to reduce banding, then image quality is improved, but printing speed decreases
Solution Approach 1:
The patent applies dynamics by making the sub-scanning distance adjustable rather than fixed. The sub-scanning control unit dynamically changes the sub-scanning distance based on print image density requirements, allowing the system to switch between overlap printing (for high density areas to prevent banding) and non-overlap printing (for low density areas to maintain speed), thus resolving the contradiction between image quality and printing speed
Solution Approach 2:
The patent changes the parameter of sub-scanning distance based on print image density. When record density is high, the sub-scanning distance is reduced to create overlap between print regions, suppressing banding. When record density is low, the sub-scanning distance is increased to eliminate overlap, improving printing speed. This parameter change strategy resolves the technical contradiction by adapting the printing mode to the specific requirements of different image regions
2Manufacturing precision
If ink droplet size is changed in link portion to match non-link portion, then image density uniformity is improved, but device complexity increases
Solution Approach 1:
Instead of physically changing ink droplet size through complex hardware modifications, the patent changes the parameter of sub-scanning distance to control print region overlap. This parameter change approach achieves uniform image density without increasing device complexity, as it uses software-based control of the printing process rather than hardware modifications
Solution Approach 2:
The patent replaces the mechanical approach of changing ink droplet size with a control-based approach of adjusting sub-scanning distance. By substituting mechanical modification with process control, the system achieves the same goal of uniform image density while avoiding increased device complexity
Data Source
AI summary
Main scanning performed two times by interposing sub-scanning of a distance longer than a pitch of nozzles of s nozzle line in the sub-scanning direction is referred to as first main scanning and second main scanning, a region in which a print image is formed at s time of the first main scanning is referred to as a first print region, and a region in which the print image is formed at a time of the second main scanning is referred to as a second print region. A printing control device for a printing unit (printing apparatus) includes a record density acquisition unit that acquires record density of the print image in a determination region including at least a part of the first print region based on the print data; and a sub-scanning control unit that changes an overlap between the first and second print regions in the sub-scanning direction.