Nozzle Cap Ultrasonic Cleaning for Uniform Liquid Ejection
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Solution Overview
Problem
In existing liquid ejection devices, ultrasonic waves are reflected due to differences in acoustic impedance between the cap and liquid, reducing transmission intensity and leading to inefficient and uneven cleaning of ejection nozzles.
Innovation Solution
The device includes a cap that holds cleaning liquid and an ultrasonic device in contact with the liquid, with ultrasonic elements arranged to transmit waves directly to the liquid, and a drive controller to focus waves on specific nozzles, using a frequency formula f>6/D to generate small bubbles for efficient cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic waves are propagated through the cap to clean nozzles, then cleaning function is provided, but ultrasonic wave transmission intensity is reduced due to acoustic impedance difference
Solution Approach 1:
The patent introduces cleaning liquid as an intermediary medium between the ultrasonic transducer and the nozzle. The ultrasonic transducer is arranged to contact the cleaning liquid directly, and the cleaning liquid is supplied to contact the nozzle outer surface. This intermediary liquid medium resolves the acoustic impedance mismatch problem by providing a continuous liquid path for ultrasonic wave transmission from the transducer through the cleaning liquid to the nozzle, eliminating the need for direct solid-to-liquid contact through the cap material.
2Reliability
If ultrasonic waves are transmitted through the cap, then nozzle cleaning is achieved, but cleaning uniformity is poor due to wave reflection
Solution Approach 1:
The cleaning liquid serves as an intermediary that eliminates acoustic impedance boundaries. By supplying cleaning liquid to contact the nozzle outer surface and arranging the ultrasonic transducer to contact the cleaning liquid, the system creates a homogeneous liquid medium that allows uniform ultrasonic wave propagation without reflections at solid-liquid interfaces, thereby achieving uniform cleaning across the nozzle surface.
Solution Approach 2:
The patent changes the physical state and arrangement of the cleaning medium from a contained liquid in a cap to a supplied liquid that directly contacts both the transducer and nozzle. This parameter change in the cleaning liquid's position and contact arrangement enables direct ultrasonic wave transmission path, improving wave penetration and cleaning uniformity by eliminating intermediate solid structures that cause reflections.
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
Enhances ultrasonic wave transmission and cavitation, allowing for selective and efficient cleaning of nozzles, improving cleaning effectiveness and reducing uneven cleaning issues.
Implementation Method 1
an ultrasonic device that transmits ultrasonic waves to the cleaning liquid... generate small bubbles for efficient cleaning
Data Source
AI summary
A liquid ejection device 1 includes a head 10 including at least one nozzle 11 that ejects ejection liquid; a cap 20 that covers the nozzle 11 and that holds cleaning liquid 23 therein; and an ultrasonic device 25 that transmits ultrasonic waves 24 to the cleaning liquid 23, wherein the cleaning liquid 23 contacts the at least one nozzle 11 and the ultrasonic device 25 is arranged so as to be in contact with the cleaning liquid 23 in the cap 20.