Inkjet Head Drive Circuit for Volatile Ink Fluidity
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Solution Overview
Problem
Existing inkjet technologies face challenges in maintaining high-quality printing with highly volatile inks, such as solvent-based inks, due to increased viscosity and solidification, which can lead to nozzle clogging and deteriorated printing quality over time.
Innovation Solution
The inkjet head employs a drive circuit that generates specific signal patterns to manage ink vibration within the pressure chamber, including a first precursor process to reduce viscosity, a discard printing process to eject ink from the meniscus, and a second precursor process to maintain ink fluidity, ensuring stable ink ejection and preventing re-solidification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a highly volatile ink such as solvent-based ink is used, then printing speed and color quality can be improved, but ink viscosity increases and ink solidifies due to rapid volatilization from the ink meniscus
Solution Approach 1:
The system performs preliminary actions before actual printing to prevent ink solidification. A first precursor process outputs a first signal that vibrates ink in the pressure chamber without ejecting it from the nozzle, preparing the ink for subsequent printing operations. This preliminary vibration prevents viscosity increase before it occurs during normal printing.
Solution Approach 2:
The system employs periodic vibration signals to continuously agitate the ink in the pressure chamber. The drive circuit outputs periodic first signals that create vibrations in the ink, preventing solidification during non-printing periods. This periodic action maintains ink fluidity without requiring continuous ink ejection.
2Reliability
If slight vibration is applied to ink in the pressure chamber to prevent solidification, then ink viscosity increase is reduced, but this vibration is insufficient to cause ink ejection from the nozzle
Solution Approach 1:
The driving signal is segmented into distinct types: first signals for vibration without ejection, second signals for actual ink ejection, and third signals for post-ejection vibration. This segmentation allows the system to optimize each phase independently - using gentle vibration to maintain fluidity and stronger signals only when ejection is required, thus resolving the contradiction between preventing solidification and enabling efficient ejection.
Solution Approach 2:
The system dynamically adjusts the driving signal characteristics based on the operational phase. During non-printing periods, low-amplitude periodic signals maintain ink fluidity. During printing, higher-amplitude signals are applied to achieve ejection. This dynamic adaptation allows the same system to fulfill both requirements of preventing solidification and enabling ejection.
3Reliability
If ink is continuously ejected from the nozzle during non-printing time to prevent solidification, then ink fluidity is maintained, but ink is wasted and printing quality may still deteriorate
Solution Approach 1:
Instead of continuously ejecting ink, the system performs preliminary vibration actions in the pressure chamber that prevent solidification without requiring ejection. The first precursor process vibrates the ink in-place, eliminating the need for wasteful continuous ejection during non-printing periods while still maintaining ink fluidity.
Solution Approach 2:
The system extracts only the essential function of ink vibration from the ejection process. By separating the vibration function (performed by first signals in the pressure chamber) from the ejection function (performed by second signals at the nozzle), the system eliminates wasteful continuous ejection while maintaining the beneficial effect of ink agitation.
4Reliability
If multiple signal types are used to manage ink vibration and ejection, then ink fluidity is maintained and printing quality is improved, but device complexity increases
Solution Approach 1:
The drive circuit is designed with multi-functionality, using a single circuit to generate multiple types of driving signals (first signals for vibration, second signals for ejection, third signals for post-vibration). This universal approach allows one circuit to perform multiple functions that would otherwise require separate dedicated circuits, reducing overall system complexity while maintaining the benefits of multiple signal types.
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 enables high-quality printing with highly volatile inks by reducing viscosity, preventing nozzle clogging, and maintaining ink fluidity, thereby improving printing quality and reliability.
Implementation Method 1
an actuator configured to change a volume of the pressure chamber
Implementation Method 2
a second signal for changing the volume of the pressure chamber for ejecting ink from the nozzle
Data Source
AI summary
An inkjet head includes a pressure chamber in which ink is stored, a nozzle plate including a nozzle which connects with the pressure chamber, an actuator configured to change a volume of the pressure chamber, and a drive circuit. The drive circuit, before a printing is performed, outputs, to the actuator for a first time period, a first signal for changing the volume of the pressure chamber without ejecting ink from the nozzle. A second signal for changing the volume of the pressure chamber is then output to the actuator for a second time period such that ink is ejected from the nozzle. A third signal for changing the volume of the pressure chamber to the extent that the ink is not ejected from the nozzle is then output to the actuator for a third time period.