Overlapping Printhead Nozzle Control to Prevent Joint-Area Drying
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Solution Overview
Problem
Ejection failures in nozzles are likely to occur due to drying when the ejection frequency is low, particularly in configurations where multiple heads are aligned in the conveyance direction of a printing medium, leading to reduced ejection amounts per pass and increased nozzle drying.
Innovation Solution
The apparatus includes first and second heads with overlapping nozzles in a joint area, a controller that processes image data to identify dark areas requiring increased ejection, and adjusts the number of nozzles used in subsequent passes to ensure sufficient ink volume, thereby reducing ejection failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple heads are aligned in the conveyance direction and singling printing is carried out to reduce stripe appearance at joints, then printing quality is improved, but ejection frequency of each nozzle is reduced causing nozzle drying and ejection failure
Solution Approach 1:
The patent combines multiple heads (first head and second head) to print in the same conveyance direction, with their nozzles overlapping in a joint area. By coordinating ejection between the two heads, the system maintains higher effective ejection frequency while still performing singling printing to reduce stripe appearance, thus resolving the contradiction between printing quality and nozzle reliability
Solution Approach 2:
The controller determines in advance whether the joint area corresponds to a dark area requiring increased ink volume. Based on this preliminary determination, it adjusts the number of nozzles to be used before execution, ensuring that nozzles in the joint area maintain sufficient ejection frequency and avoid drying, thereby preventing ejection failure while maintaining print quality
2Manufacturing precision
If the number of nozzles to be used is reduced in the joint area, then stripe appearance at joints is reduced, but ejection frequency decreases causing nozzle drying
Solution Approach 1:
The system dynamically adjusts the number of nozzles to be used based on the determined dark area information. The controller flexibly modifies nozzle utilization in the joint area according to actual printing needs, balancing the reduction of stripe appearance with maintenance of sufficient ejection frequency to prevent nozzle drying
Solution Approach 2:
The controller uses feedback from the determined dark area information to adjust nozzle ejection strategies. By monitoring whether the joint area corresponds to dark areas requiring increased ink volume, the system adapts nozzle usage to maintain both print quality and nozzle reliability, preventing ejection failure through intelligent control
Data Source
AI summary
A liquid droplet ejecting apparatus includes: a first head configured to eject first liquid droplets from a plurality of first nozzles based on image data; a second head configured to eject second liquid droplets of a same color as a color of the first liquid droplets from a plurality of second nozzles based on the image data; a conveyor configured to convey a printing medium in a conveyance direction; a first moving device configured to move the first head and the second head in a movement direction crossing the conveyance direction; and a controller. The first head and the second head are disposed such that positions of first nozzles as a part of the plurality of first nozzles and positions of second nozzles as a part of the plurality of second nozzles overlap with one another in the conveyance direction in a predetermined joint area.