Liquid Ejecting Apparatus Nozzle Height Compensation
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Solution Overview
Problem
Liquid ejecting apparatuses with sloped nozzle surfaces face irregular back pressure on nozzles due to height differences, affecting droplet discharge properties, especially in longer nozzle arrays, leading to inconsistent image quality and potential dripping or failure to discharge liquid.
Innovation Solution
The apparatus features a supply passage that adjusts the flow rate to cancel out pressure differences between nozzles by incorporating an inflow and outflow configuration, ensuring uniform liquid surface heights and pressures across the nozzle array, with the flow rate adjusted according to the nozzle height difference and ink properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the nozzle array length is increased to discharge larger amounts of liquid droplets, then productivity is improved, but manufacturing precision deteriorates due to irregular back pressure on nozzles at different heights
Solution Approach 1:
The patent applies local quality by providing different supply passage lengths to nozzles at different heights. Specifically, nozzles at higher positions are equipped with longer supply passages while nozzles at lower positions have shorter supply passages. This local differentiation compensates for the height difference effect, ensuring that all nozzles receive liquid at appropriate pressures regardless of their vertical position, thereby maintaining droplet discharge uniformity across the entire nozzle array.
2Ease of operation
If nozzles are positioned at different heights to accommodate sloped nozzle surface design, then ease of operation is improved, but reliability deteriorates due to irregular back pressure affecting meniscus formation
Solution Approach 1:
The patent maintains the sloped nozzle surface design for ease of operation while compensating for reliability issues by implementing local quality adjustments in the supply passage configuration. Each nozzle receives a customized supply passage length matched to its height position, ensuring consistent liquid pressure and proper meniscus formation despite the varying nozzle heights and sloped surface geometry.
3Manufacturing precision
If the supply passage length is increased to compensate for height difference, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the supply passage length parameter according to nozzle height. Instead of using uniform supply passages, the invention adjusts the length parameter of supply passages to match the vertical positions of different nozzles. This parameter adjustment approach achieves uniform droplet discharge while maintaining a relatively simple overall device structure, as the complexity is reduced to a single dimensional variation (length) rather than requiring complex multi-parameter adjustments.
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 ensures uniform discharge of liquid droplets, reducing variations in droplet properties and preventing dripping or improper meniscus formation, thereby enhancing image quality and operational reliability.
Implementation Method 1
A height of the first end nozzle is set to be greater than a height of the second end nozzle. The liquid flows through the supply passage in a direction from the first end nozzle to the second end nozzle.
Implementation Method 2
the difference between the pressures generated in the nozzles, namely, the difference between the pressures generated in the nozzles which is attributed to the difference in height between the surfaces of the liquid in the nozzles is successfully canceled by a pressure loss of the liquid flowing through the supply passage
Data Source
AI summary
A liquid ejecting apparatus includes: a liquid ejecting head including a plurality of nozzles for discharging liquid and a supply passage through which the liquid to be supplied to the plurality of nozzles flows. The nozzles are arranged in a line; one of the nozzles at a first end of the line being a first end nozzle, whereas one of the nozzles at a second end of the line being a second end nozzle. A height of the first end nozzle is set to be greater than a height of the second end nozzle. The liquid flows through the supply passage in a direction from the first end nozzle to the second end nozzle.