Inkjet Droplet Positioning for Long-Dot Optical Density
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Solution Overview
Problem
The formation of vacant spaces between long-length dots ejected as extra-large liquid droplets leads to a decrease in optical density when printing, as the droplets align in a short direction orthogonal to their longitudinal direction.
Innovation Solution
A liquid ejecting apparatus that includes a head with nozzles capable of ejecting first and second liquid droplets of varying sizes, along with a controller that adjusts the relative positions of these droplets to form continuous dots, shifting their alignment to reduce the decrease in optical density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If extra-large liquid droplets are ejected to form long-length dots, then the droplet size and coverage area are improved, but vacant spaces are generated between adjacent dots causing optical density to decrease
Solution Approach 1:
The patent segments the ejection process into multiple phases: a first liquid droplet is ejected initially, then a second liquid droplet is ejected subsequently from the same nozzle. This segmentation allows the formation of composite dots where the first droplet forms the base and the second droplet supplements it, eliminating vacant spaces between adjacent dots while maintaining appropriate droplet sizes.
Solution Approach 2:
The controller performs preliminary positioning by ejecting the first liquid droplet before ejecting the second liquid droplet. This preliminary action establishes the base dot position, and the subsequent second droplet is positioned to overlap or adjacent to the first droplet, ensuring continuous coverage without vacant spaces while maintaining optical density.
2Stability of the object's composition
If long-length dots are aligned in the short direction, then the dot continuity is improved, but vacant spaces are generated at the end parts causing optical density to decrease
Solution Approach 1:
The patent merges the formation of adjacent dots by having the first and second liquid droplets combine to form a single composite dot structure. The second droplet is positioned to overlap or adjacent to the first droplet, causing them to merge into a continuous structure without vacant spaces, thereby maintaining both dot continuity and optical density.
Solution Approach 2:
The controller applies different ejection strategies to different positions: the first droplet is ejected at a initial position, and the second droplet is ejected at a subsequent position that overlaps or adjoins the first. This local quality adjustment ensures that at the end parts of aligned dots, the droplets are positioned to eliminate vacant spaces while maintaining continuity.
Data Source
AI summary
A liquid ejecting apparatus includes: a head configured to eject, to a medium, a first liquid droplet and a second liquid droplet in which size in an ejection direction is longer and volume is greater than in the first liquid droplet; a moving device configured to move the head relative to the medium in a first direction; and a controller. The controller is configured to execute: generation of second print data based on image data, two continuous second liquid droplets being located in the second print data to be further away from each other in the first direction than in first print data which includes information designating the second liquid droplet; and formation of the image on the medium based on the second print data.