Opposing Liquid Flow in Inkjet Heads
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Solution Overview
Problem
Liquid ejecting apparatuses with line-type recording heads experience uneven droplet ejection due to pressure differences between adjacent nozzles, leading to concentration unevenness on the ejected object.
Innovation Solution
A liquid ejecting apparatus with a common liquid chamber and opposing liquid supply and discharge channels between adjacent heads, ensuring opposite liquid flow directions and matching nozzle-to-nozzle distances to reduce droplet differences and prevent discontinuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid is circulated through reservoirs in the same direction in adjacent recording heads, then liquid circulation is achieved for preventing foreign substance accumulation, but pressure differences between upstream and downstream nozzles cause uneven droplet ejection amounts
Solution Approach 1:
The patent applies inversion by making the liquid circulation direction in adjacent recording heads opposite to each other. Specifically, the liquid circulation direction in an odd-numbered recording head is set opposite to that in an even-numbered recording head. This causes the upstream side of one head to align with the downstream side of the adjacent head, equalizing pressures and eliminating the uneven droplet ejection caused by pressure differences while maintaining effective liquid circulation.
2Manufacturing precision
If liquid circulation direction is made opposite in adjacent recording heads, then pressure differences between nozzles are reduced, but liquid flow paths become more complex
Solution Approach 1:
The patent applies segmentation by dividing the liquid circulation system into independent circulation paths for each recording head. Each recording head has its own liquid circulation path with supply and discharge channels, allowing the circulation direction to be independently controlled in adjacent heads. This segmented approach enables opposite circulation directions in adjacent heads without requiring a completely redesigned complex flow path system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces droplet differences between adjacent nozzles, inhibiting unevenness in liquid concentration on the ejected object, ensuring consistent ejection and improved printing quality.
Implementation Method 1
the pressure is relatively high on the upstream side and is relatively low on the downstream side
Data Source
AI summary
A liquid ejecting apparatus including: a plurality of pressure chambers communicating with a plurality of nozzles respectively; and a plurality of liquid ejecting heads having a common liquid chamber configured to supply liquid common to the plurality of pressure chambers, wherein each of the liquid ejecting heads includes a liquid supply channel communicating with the common liquid chamber and supplying liquid from the liquid storage tank toward the common liquid chamber by the liquid feeding unit and a liquid discharge channel communicating with the common liquid chamber and discharging the liquid from the communicating chamber toward the liquid storage tank by the liquid feeding unit, and the directions of flows of the liquid in the common liquid chamber flowing from the liquid supply channels through the common liquid chamber toward the liquid discharge channels are opposite from each other between the adjacent liquid ejecting heads.