Liquid Discharge Head Asymmetric Throttle Channels
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Solution Overview
Problem
Existing liquid discharge heads experience uneven ink supply to pressure chambers, leading to unstable ink discharge from nozzles due to differences in channel resistances and chamber volumes, causing variations in discharge amounts.
Innovation Solution
A liquid discharge head design with an individual channel configuration where the downstream-side throttle channel has a smaller channel resistance than the upstream-side throttle channel, and both pressure chambers have equal volumes, ensuring stable ink supply and discharge by adjusting the driving pulse signals for the actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the liquid is allowed to flow from the supply channel toward the recovery channel while passing through the individual channels, then the supply of liquid to the upstream-side pressure chamber is maintained, but the supply of liquid to the downstream-side pressure chamber becomes insufficient due to reverse flow direction
Solution Approach 1:
The patent applies asymmetry by making the channel resistance of the downstream-side throttle channel smaller than that of the upstream-side throttle channel. This asymmetric design compensates for the unfavorable reverse flow direction to the downstream-side pressure chamber, ensuring balanced liquid supply to both pressure chambers and stable discharge performance.
2Productivity
If the volume of the second pressure chamber is made small as compared with the volume of the first pressure chamber, then the discharge performance is improved, but the manufacturing precision and structural complexity increase
Solution Approach 1:
The patent changes the parameter of channel resistance in the throttle channels to compensate for the volume difference between pressure chambers. By adjusting the resistance parameters rather than relying solely on precise volume control, the system achieves balanced liquid supply and stable discharge without requiring high manufacturing precision for chamber volumes.
3Reliability
If different channel resistances are used for upstream-side and downstream-side throttle channels, then the liquid supply balance is improved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by creating a specific resistance difference only in the downstream-side throttle channel while keeping other channel dimensions similar. This localized modification achieves the necessary liquid supply balance without requiring complex variations throughout the entire channel system, thus limiting the increase in device complexity.
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 design stabilizes ink discharge from nozzles by minimizing differences in ink supply to pressure chambers, enhancing discharge efficiency and reducing the risk of unstable ink flow, while also simplifying the driver IC control and reducing heating.
Implementation Method 1
a first piezoelectric element (upstream-side actuator) which applies pressure to the ink inside the first pressure chamber and a second piezoelectric element (downstream-side actuator) which applies pressure to the ink inside the second pressure chamber are driven to thereby cause the ink to be discharged (jetted) from the nozzle
Data Source
AI summary
A liquid discharge head includes: an individual channel having an inlet and an outlet, the individual channel including: a nozzle, an upstream-side pressure chamber arranged between the inlet and the nozzle, a downstream-side pressure chamber arranged between the outlet and the nozzle, an upstream-side throttle channel connecting the inlet and the upstream-side pressure chamber, and a downstream-side throttle channel connecting the outlet and the downstream-side pressure chamber; a supply channel connected to the inlet and configured to supply liquid to the individual channel; a recovery channel connected to the outlet and configured to recover the liquid from the individual channel; an upstream-side actuator configured to apply pressure to the liquid inside the upstream-side pressure chamber; and a downstream-side actuator configured to apply the pressure to the liquid inside the downstream-side pressure chamber. The channel resistance of the downstream-side throttle channel is smaller than that of the upstream-side throttle channel.