Liquid Discharging Apparatus Circulation Control
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Solution Overview
Problem
Circulation-type liquid discharging apparatuses face issues with excessively negative pressure in the liquid chamber, leading to air inhalation and bubble entry due to inertial forces when the circulation operation is stopped, causing inefficiencies and potential contamination.
Innovation Solution
The apparatus incorporates a circulation controller that lowers the flow velocity of the liquid before stopping the circulation operation, and in some embodiments, raises the pressure in the liquid storing chamber to prevent negative pressure buildup, thereby reducing inertial forces and minimizing air inhalation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the circulation operation is stopped abruptly, then the liquid discharge function can be maintained during operation, but excessively negative pressure is generated in the liquid chamber due to inertial force
Solution Approach 1:
The circulation controller lowers the flow velocity of the liquid before stopping the circulation operation. This preliminary action reduces the inertial force that would otherwise cause excessively negative pressure when circulation stops abruptly, while still maintaining effective liquid discharge during operation.
2Productivity
If the flow velocity in circulation operation is high, then liquid circulation efficiency is improved, but inertial force increases causing air inhalation when circulation stops
Solution Approach 1:
The circulation controller lowers the flow velocity before stopping circulation, which is a preliminary action that prevents inertial force from causing air inhalation. This allows the system to maintain high circulation efficiency during operation while avoiding harmful effects when circulation stops.
Solution Approach 2:
The circulation controller raises the pressure in the liquid storing chamber above the pressure during discharge operation before stopping circulation. This preliminary anti-action counteracts the harmful effect of inertial force that would otherwise cause air inhalation and bubble entry when circulation stops.
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 approach effectively suppresses the generation of excessively negative pressure and reduces the likelihood of bubble entry into the liquid, enhancing operational efficiency and preventing contamination.
Implementation Method 1
the inertial force of the liquid may cause an excessively negative pressure in a liquid chamber in the liquid discharging head
Implementation Method 2
The circulation controller raises the pressure of the liquid in the liquid storing chamber above the pressure of the liquid in the liquid storing chamber with the discharge operation being in progress
Data Source
AI summary
A liquid discharging apparatus has: a liquid storing chamber storing a liquid to be discharged from a discharge opening; a supply flow path supplying the liquid to the liquid storing chamber; a discharge flow path discharging the liquid from the liquid storing chamber; a circulation controller controlling a circulation operation to circulate, to the supply flow path, the liquid discharged through the discharge flow path; and a discharge controller controlling a discharge operation to discharge the liquid from the discharge opening. The circulation controller lowers the flow velocity of the liquid in the circulation operation below the flow velocity of the liquid in the circulation operation with the discharge operation being in progress, after which the circulation controller stops the circulation operation.