Liquid Ejecting Head Valve Stability via Pump Control
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Solution Overview
Problem
Existing liquid ejecting apparatuses face instability in valve element operation due to small liquid flow or low downstream pressure, leading to unstable liquid flow and degraded precipitation suppression in liquid ejecting heads.
Innovation Solution
A control method for liquid ejecting apparatuses that includes first and second control modes to stabilize valve element operation by adjusting pressures in inflow and outflow channels, using a flexible film to open the valve element with an external force when the flow amount is below a threshold, ensuring stable liquid flow generation and minimizing meniscus breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a valve element is opened on the basis of a negative pressure on the downstream side of the valve element and the atmospheric pressure, then the liquid flow is generated in the liquid ejecting head, but the opening operation of the valve element becomes unstable when the amount of liquid flow is small or where the pressure on the downstream side of the valve element is small
Solution Approach 1:
A pump is introduced to preliminarily generate liquid flow through the liquid ejecting head before the valve element opening operation. This preliminary action ensures that the liquid flow is already present when the valve element needs to open, preventing the instability that occurs when attempting to open the valve element with insufficient liquid flow. The pump actively creates the necessary flow conditions in advance, making the subsequent valve operation reliable.
Solution Approach 2:
The pump acts as an intermediary device between the liquid supply system and the valve element. It mediates the liquid flow generation process by actively pumping liquid through the system, ensuring that adequate flow is present to support stable valve element operation. This intermediary action resolves the contradiction by providing the necessary flow conditions without relying solely on the valve element's opening action.
2Reliability
If the valve element opening operation becomes unstable, then the liquid flow generated in the liquid ejecting head becomes unstable, but the effect of suppressing precipitation of components of liquid is degraded
Solution Approach 1:
The pump performs preliminary action by generating liquid flow through the liquid ejecting head before and during the valve element opening operation. This ensures that the liquid is already moving when the valve opens, preventing flow instability that would otherwise occur. The continuous liquid flow generated by the pump suppresses precipitation of liquid components by maintaining adequate circulation and preventing stagnation.
Solution Approach 2:
The pump maintains continuous liquid flow through the liquid ejecting head, ensuring that the liquid is constantly moving. This continuous action prevents interruptions or instabilities in the liquid flow that would occur with unstable valve element operation. The uninterrupted flow continuously suppresses precipitation of liquid components, maintaining system reliability.
3Reliability
If a pump is introduced to generate liquid flow, then the valve element opening operation is stabilized, but the device complexity increases
Solution Approach 1:
The pump is designed to perform multiple functions: it generates liquid flow through the liquid ejecting head, stabilizes valve element opening operation, and suppresses liquid component precipitation. By consolidating these multiple functions into a single device, the overall system complexity is minimized while achieving the desired reliability improvements. The pump's multi-functionality justifies its addition to the system.
Solution Approach 2:
The pump enables control of liquid flow parameters (flow rate, pressure) to optimize valve element operation. By adjusting these parameters, the system achieves stable valve opening without requiring complex mechanical modifications. The parameter control approach simplifies the overall system design compared to mechanical complexity solutions.
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
The method stabilizes valve element operation, suppresses liquid stagnation, and facilitates easy bubble discharge by selectively switching pressure modes, maintaining optimal flow and pressure to prevent meniscus breakage and enhance liquid flow stability.
Implementation Method 1
a pump that feeds the liquid to the liquid ejecting unit
Implementation Method 2
a valve element that opens and closes the inflow channel. The liquid ejecting apparatus can be controlled by first control of opening the inflow channel by opening the valve element in accordance with a negative pressure on a downstream side of the valve element
Data Source
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AI summary
A control method of a liquid ejecting apparatus is provided. The liquid ejecting apparatus includes a liquid ejecting head that has an inner space through which a liquid flows and that ejects the liquid in the inner space through a nozzle, an inflow channel through which the liquid flows into the inner space, an outflow channel through which the liquid in the inner space flows out, and a valve element that opens and closes the inflow channel. The control method includes first control of opening the inflow channel by opening the valve element in accordance with a negative pressure on a downstream side of the valve element to generate a liquid flow from the inflow channel to the outflow channel through the inner space, second control of opening the inflow channel by opening the valve element by an external force to generate the liquid flow from the inflow channel to the outflow channel through the inner space, and performing the second control, in accordance with a flow amount of the liquid flow, to open the valve element that opens by the first control.