Inkjet Nozzle Offset for Uniform Functional Liquid Coating
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Solution Overview
Problem
Inkjet printers face issues with uneven coating lines when discharging multiple functional liquids onto a substrate, leading to conspicuous defects and inefficient scanning processes, particularly when nozzles at the ends of discharge heads overlap, causing uneven distribution and prolonged discharge times.
Innovation Solution
The method involves shifting the nozzles on each discharge head in an orthogonal direction relative to the scanning direction, ensuring that the overlapped discharge area includes part of the coated area along the scanning direction, allowing for simultaneous discharge of all functional liquids in a single scan without overlapping uneven coating lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nozzles are aligned at both ends of discharge heads to discharge multiple functional liquids simultaneously, then discharge duration is shortened, but uneven coating lines become more conspicuous
Solution Approach 1:
The patent applies asymmetry by intentionally misaligning the nozzle positions of adjacent discharge heads in the scanning direction. Specifically, the nozzles of each discharge head are positioned at different locations along the scanning direction, creating an asymmetric arrangement that prevents the overlapping of uneven coating lines from different heads while maintaining simultaneous discharge capability.
2Extent of automation
If nozzles are aligned at both ends of discharge heads to discharge multiple functional liquids simultaneously, then all variations can be discharged in one scan, but uneven coating lines from different heads overlap
Solution Approach 1:
The patent implements asymmetry by positioning nozzles of different discharge heads at offset locations in the scanning direction. This asymmetric arrangement ensures that when multiple discharge heads operate simultaneously in one scan, their uneven coating lines do not coincide, thereby maintaining both single-scan capability and coating uniformity.
3Productivity
If discharge heads scan over coated area with nozzles at orthogonal edges, then discharge efficiency is improved, but uneven coating lines occur at nozzle locations
Solution Approach 1:
The patent applies local quality by recognizing that different regions of the discharge head have different characteristics. The nozzles at the ends of the discharge head (orthogonal edges) inherently produce uneven coating lines. By offsetting the positions of nozzles from adjacent heads, the patent ensures that these local defects do not overlap, thereby maintaining overall coating uniformity while preserving the high efficiency of orthogonal edge nozzle arrangement.
Data Source
AI summary
A method for discharging droplets includes: discharging droplets of a plurality of variations of functional liquids by a plurality of discharge heads, on a coated area from a plurality of nozzles installed in each of the discharge heads, while scanning relatively over the coated area provided on a substrate; wherein a location of the nozzles is shifted in an orthogonal direction for each of the discharge heads, the nozzles being installed in an orthogonal direction on both edges whose direction is approximately orthogonal to a scanning direction, and, at the same time, the plurality of nozzles being arranged in each of the discharge heads, so that an overlapped discharge area, where discharge areas of all variations of the functional liquid overlap upon scanning, is formed; and wherein the discharge heads perform scanning so that the overlapped discharge area includes at least part of the coated area that is provided along a side that extends in the scanning direction, when discharging droplets of the functional liquid on the coated area that is provided along the side that extends in the scanning direction, the discharge heads being located on the edge of the orthogonal direction in the substrate.