Liquid Discharge Apparatus Volume Control for Leakage Prevention

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Solution Overview

Problem

Existing liquid discharge apparatuses face issues with liquid leakage and air suction due to variations in flow-channel resistance, which are not effectively addressed by current technologies.

Innovation Solution

The apparatus employs a control mechanism that adjusts the volume of the liquid chamber and flow channels using piezoelectric actuators to manage flow-channel resistance, ensuring that the liquid chamber contains the liquid and prevents external air suction by synchronizing the operations of supply and emission valves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the inner wall surface of the liquid flow channel is shifted to decrease the sectional area of the flow channel in order to increase flow-channel resistance, then the flow-channel resistance is increased, but liquid is pushed from the flow channel to the liquid chamber and leaks from nozzles

Engineering Contradiction:
Improveflow-channel resistance controlVSAvoidliquid leakage
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The liquid chamber volume is increased in advance before the flow channel volume is decreased. This preliminary expansion of the liquid chamber creates sufficient space to accommodate the liquid that will be pushed from the flow channel, preventing liquid leakage from the nozzles while still allowing the flow channel resistance to be increased effectively

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention dynamically coordinates the volume changes of both the liquid chamber and flow channel during operation. By making the liquid chamber volume increase at least equal to the flow channel volume decrease, the system adaptively manages liquid pressure and flow to prevent leakage while maintaining controllable flow resistance

Inventive Principle:
Principle #15Dynamics

2Reliability

If the inner wall surface of the liquid flow channel is shifted to increase the sectional area of the flow channel in order to decrease flow-channel resistance, then the flow-channel resistance is decreased, but liquid flows from the liquid chamber to the flow channel and external air is suctioned in from nozzles

Engineering Contradiction:
Improveflow-channel resistance controlVSAvoidair suction
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The liquid chamber volume is decreased in advance before the flow channel volume is increased. This preliminary compression creates sufficient space accommodation, preventing liquid from flowing into the flow channel and external air from being suctioned through the nozzles while still allowing flow channel resistance to be decreased

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically coordinates volume changes by making the liquid chamber volume decrease at least equal to the flow channel volume increase. This dynamic adjustment prevents air suction and liquid misflow while maintaining effective flow resistance control

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If separate driving units are used for supply valve and emission valve to achieve independent control, then control precision is improved, but device complexity increases

Engineering Contradiction:
Improvevalve control precisionVSAvoidnumber of driving units
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A single driving unit is used to control both the supply valve and emission valve. This merging of control functions reduces the number of driving units and simplifies the device structure, while the controller can still independently regulate each valve's opening degree to maintain precise control over liquid supply and emission

Inventive Principle:
Principle #5Merging (Combining)

4Device complexity

If the volume of the liquid chamber is not adjusted during flow channel volume changes, then device complexity is reduced, but liquid leakage and air suction occur

Engineering Contradiction:
Improvecontrol mechanismVSAvoidliquid leakage and air suction
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The liquid chamber volume is adjusted in advance before flow channel volume changes occur. This preliminary adjustment ensures that the liquid chamber has sufficient capacity to handle the resulting liquid flow changes, preventing both liquid leakage and air suction without requiring complex real-time monitoring systems

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The liquid chamber volume is dynamically adjusted in coordination with flow channel volume changes. By making the volume adjustment at least equal to the flow channel change, the system effectively prevents harmful effects while maintaining a relatively simple control structure

Inventive Principle:
Principle #15Dynamics

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 liquid leakage and air suction, reduces the apparatus size, and allows for easy synchronization of valve operations, thereby improving the overall efficiency and reliability of liquid discharge.

Implementation Method 1

a liquid chamber driving unit (43) which changes a volume of the liquid chamber (42)

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3381701B1Liquid discharge apparatus and method for controlling the same
Publication Date: 2020.05.13 SEIKO EPSON CORP
  • EP3381701B1 patent drawingFigure 1~2
  • EP3381701B1 patent drawingFigure 3
  • EP3381701B1 patent drawingFigure 4A~4C

AI summary

There is provided a liquid discharge apparatus including: a liquid chamber that communicates with a nozzle; a liquid chamber driving unit that changes a volume of the liquid chamber so as to discharge the liquid from the nozzle; a flow channel which is connected to the liquid chamber; and a valve that changes a volume of the flow channel so as to control flow of the liquid. At least one of first control of increasing the volume of the liquid chamber in association with a decrease in volume of the flow channel by the valve, such that a change amount of the volume of the liquid chamber is equal to or larger than a volume of the liquid flowing from the flow channel into the liquid chamber due to the decrease in volume of the flow channel, and second control of decreasing the volume of the liquid chamber in association with an increase in volume of the flow channel by the valve, such that a change amount of the volume of the liquid chamber is equal to or larger than a volume of the liquid flowing from the liquid chamber out to the flow channel due to the increase in volume of the flow channel, is executed.