Liquid Ejection Head Asymmetric Flow Resistance
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Solution Overview
Problem
Existing liquid ejection heads face challenges with increased viscosity of liquids near the ejection orifice, leading to changes in droplet ejection speed and landing precision, and require significant electric power for temperature adjustment to lower viscosity, especially when downtime is long and volatile components evaporate, causing clogging and flow resistance issues.
Innovation Solution
The implementation of a liquid ejection head with a circulation path that includes pressure adjustment mechanisms to manage the flow rate and temperature of the liquid, using a configuration where the flow resistance of the supply path is greater than the collection path, reducing the need for high electric power by balancing the liquid supply and collection flow rates and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circulation path is formed to circulate liquid through the pressure chamber, then the evaporation of volatile components is suppressed and clogging is prevented, but a large amount of low-temperature liquid is supplied from the supply side requiring rapid heating and large electric power
Solution Approach 1:
The patent applies asymmetry by making the flow resistance of the supply path different from that of the collection path. Specifically, the supply path is designed with higher flow resistance than the collection path, which balances the liquid supply amounts from both sides during ejection and prevents excessive low-temperature liquid from the supply side from requiring rapid heating.
Solution Approach 2:
The patent changes the flow resistance parameter of the supply path relative to the collection path. By adjusting the flow resistance values, the system achieves balanced liquid supply from both sides, reducing the thermal load on the heating element and thereby decreasing the electric power required for temperature adjustment.
2Use of energy by moving object
If the flow resistance of the supply path is made greater than the collection path, then the liquid supply balance is improved and heating power is reduced, but the flow path design becomes more complex
Solution Approach 1:
The patent applies local quality by creating different flow resistance characteristics in different parts of the flow path system. The supply path is designed with specific flow resistance properties that differ from the collection path, allowing localized optimization of liquid flow balance without complicating the overall system design.
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 the electric power required for temperature adjustment, maintains ejection quality, and prevents clogging by balancing the flow rates and temperatures, thereby improving the efficiency and reliability of the liquid ejection process.
Implementation Method 1
a circulation flow, which flows from the supply side of a pressure chamber into the pressure chamber and flows out from the collection side of the pressure chamber, is formed by a difference in pressure between the supply side (IN side) and collection side (OUT side) of the pressure chamber
Implementation Method 2
there is a method of ejecting the liquid at low viscosity by heating the vicinity of the ejection orifice with a heater or the like
Implementation Method 3
volatile components in the liquid are evaporated from an ejection orifice that ejects the liquid, and thus the liquid in the vicinity of the ejection orifice increases in viscosity
Data Source
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AI summary
A liquid ejection head 3 includes a recording element substrate including an ejection orifice 13 for ejecting liquid, a pressure chamber 23 provided with an energy generating element 15 for generating energy used to eject liquid, a liquid supply path 18 for supplying liquid to the pressure chamber 23, and a liquid collecting path 19 for collecting liquid from the pressure chamber 23. The liquid supply path 18, the pressure chamber 23, and the liquid collecting path 19 of the recording element substrate constitute a part of a circulation path in which liquid flows in the order mentioned. The flow resistance RIn of a flow path including the liquid supply path 18 at a supply side is greater than the flow resistance ROut of a flow path including the liquid collecting path 19 at a collection side.