Liquid Ejecting Apparatus Nozzle Maintenance via Inverted Waveform
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Solution Overview
Problem
Existing liquid ejecting apparatuses face difficulties in efficiently discharging air bubbles from nozzles during the flushing process, as air bubbles tend to move into the pressure chamber during decompression, making it hard to remove them despite repeated flushing attempts.
Innovation Solution
A liquid ejecting apparatus with a detecting mechanism that applies a maintenance drive waveform to the actuator, causing the meniscus to be extruded to the ejection side without being attracted to the pressure chamber, allowing for efficient discharge of air bubbles, and reducing unnecessary liquid consumption by performing the flushing process only on abnormal nozzles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the pressure chamber is decompressed to attract the meniscus to the pressure chamber during flushing, then the liquid can be drawn into the pressure chamber, but air bubbles move to the pressure chamber and become difficult to discharge
Solution Approach 1:
Instead of first decompressing to attract the meniscus and then compressing to eject (conventional method), the invention inverts the sequence by first compressing the pressure chamber to extrude the meniscus and liquid toward the nozzle, then decompressing. This inversion prevents air bubbles from being drawn into the pressure chamber during the initial phase, allowing them to be carried outward with the liquid flow and discharged more effectively.
Solution Approach 2:
The invention converts the harmful effect of air bubbles (which obstruct liquid ejection) into a beneficial process by using the pressure variation to actively propel air bubbles outward. By compressing first, the liquid and air bubbles are both extruded toward the nozzle; the air bubbles rise to the liquid surface and are carried outward during subsequent decompression, transforming the problem of air bubble presence into an effective discharge mechanism.
2Reliability
If the flushing process is performed on all nozzles, then air bubbles may be discharged from abnormal nozzles, but unnecessary liquid is consumed on normal nozzles
Solution Approach 1:
The invention introduces a detecting mechanism that monitors each nozzle's ejection status and provides feedback to the control unit. The control unit uses this feedback to identify abnormal nozzles requiring maintenance and selectively applies the flushing process only to those specific nozzles, rather than flushing all nozzles uniformly. This feedback-based selective flushing reduces unnecessary liquid consumption while ensuring abnormal nozzles receive the required maintenance.
Solution Approach 2:
Instead of applying the same flushing treatment to all nozzles (uniform approach), the invention applies the flushing process locally only to abnormal nozzles identified by the detecting mechanism. This localized maintenance approach tailors the treatment to the specific needs of each nozzle, avoiding unnecessary liquid consumption on normal nozzles while effectively addressing the issues of abnormal ones.
3Duration of action of stationary object
If the meniscus is repeatedly attracted to the pressure chamber during flushing, then liquid can be continuously supplied, but air bubbles are trapped and cannot be discharged
Solution Approach 1:
The invention inverts the conventional flushing sequence by first compressing the pressure chamber to extrude the meniscus and liquid toward the nozzle, then decompressing. This reversed sequence ensures air bubbles are propelled outward with the liquid flow during compression and decompression, preventing them from being trapped in the pressure chamber during repeated flushing cycles.
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 discharges air bubbles from the nozzle while minimizing liquid consumption by applying the maintenance drive waveform multiple times, ensuring air bubbles are not floated into the pressure chamber, thus improving the efficiency of the flushing process.
Implementation Method 1
actuators causing a pressure variation of liquid in the pressure chamber to occur, the liquid ejecting head being able to eject the liquid from the nozzle through an action of the actuator
Implementation Method 2
at least a first-time drive waveform applied to the actuator is a maintenance drive waveform which causes a meniscus in the nozzle not to be positively attracted from an initial position to the pressure chamber, but causes the meniscus to be extruded to the ejection side and thereby causes the liquid to be ejected from the nozzle
Data Source
AI summary
When a nozzle abnormality detecting mechanism detects an abnormality of the nozzle, in the maintenance process of causing the drive waveform to be applied plural times to the actuator corresponding to the nozzle that the detecting mechanism detects as being abnormal, and thereby causing the ejecting operation to be performed, at least a first-time drive waveform applied to the actuator is a flushing pulse which causes a meniscus in the nozzle not to be positively attracted from an initial position to the pressure chamber, but causes the meniscus to be extruded to the ejection side and thereby causes the liquid to be ejected from the nozzle.