Inkjet Head Micro-Vibration Pulse Stabilization
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Solution Overview
Problem
In shared wall type ink jet heads, independently driving nozzles is challenging due to shared actuators, leading to variations in discharge speed of liquid droplets and resulting landing deviations on the medium.
Innovation Solution
A liquid droplet discharge head that applies micro-vibration pulses with specific pulse widths and timing to stabilize discharge speed by dividing nozzles into groups and controlling micro-vibration pulses before discharge pulses, ensuring consistent ink droplet placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If division driving is performed to prevent influence of adjacent nozzles, then the influence of adjacent nozzles is reduced, but discharge speed variations and landing deviations still occur
Solution Approach 1:
A micro-vibration pulse is applied to the actuator before the discharge pulse to preliminarily vibrate the liquid droplet and stabilize its discharge speed. This preliminary action ensures that even when nozzles are driven in divisions, the discharge speed remains consistent and landing position accuracy is maintained.
2Manufacturing precision
If micro-vibration pulse is applied to stabilize discharge speed, then landing deviation is reduced, but the effect varies depending on timing and shape of pulse insertion
Solution Approach 1:
The control unit adjusts parameters of the micro-vibration pulse (amplitude, duration, timing) based on the phase of division driving. By changing these parameters dynamically, the patent achieves consistent discharge speed stabilization across different phases while managing control complexity through systematic parameter adjustment.
3Device complexity
If actuator is shared between adjacent nozzles, then device complexity is reduced, but independent driving of nozzles becomes difficult
Solution Approach 1:
The patent segments the nozzle operation into multiple phases (division driving) and applies micro-vibration pulses at appropriate timing for each phase. This segmentation allows the shared actuator to service multiple nozzles while maintaining sufficient independent control capability through phase-based operation.
Solution Approach 2:
The micro-vibration pulse is applied as a preliminary action before the actual discharge pulse, allowing the shared actuator to prepare the liquid droplet for discharge. This preliminary vibration ensures consistent discharge characteristics even though the same actuator serves multiple nozzles in different phases.
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 solution effectively reduces landing deviations and stabilizes discharge speed across phases, improving the precision of ink droplet placement on the medium.
Implementation Method 1
both end surfaces of the first piezoelectric member 1 and the second piezoelectric member 2 are bonded to the base substrate 9
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
According to one embodiment, there is provided a liquid droplet discharge head including a pressure chamber, an actuator, and a drive circuit. The drive circuit is configured to apply a discharge pulse including an expansion pulse for expanding the volume in the pressure chamber and a contraction pulse for contracting the volume in the pressure chamber to the actuator when the liquid droplet is discharged, and to apply, to the actuator, a micro-vibration pulse that changes the volume of the pressure chamber to the extent that the liquid droplet is not discharged from the nozzle at a timing when the liquid droplet is not discharged. The micro-vibration pulse includes an expansion pulse portion and a contraction pulse portion. A central position of the expansion pulse portion in the micro-vibration pulse corresponds to a central position of the expansion pulse in the discharge pulse and a falling position of the contraction pulse portion in the micro-vibration pulse corresponds to a falling position.