Inkjet Nozzle Drying Prevention via Periodic Liquid Circulation
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Solution Overview
Problem
Inkjet recording apparatuses face challenges in maintaining the ink surface wetness without continuous power supply to the piezoelectric element, leading to ink drying issues.
Innovation Solution
The image forming apparatus incorporates a lowering processing portion that lowers the ink water level in the sub-ink tank with respect to the nozzle, allowing the ink to be circulated along a path through the ejection portion, thereby reducing the need for continuous power to the piezoelectric element and preventing ink drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the accommodation space is expanded to suck the ink from the ejection port into the accommodation space for circulation, then the ink surface drying is suppressed, but the power consumption increases due to continuous operation of the piezoelectric element
Solution Approach 1:
The patent implements periodic circulation of ink instead of continuous circulation. The control unit causes the piezoelectric element to vibrate at specific intervals (e.g., every several seconds to minutes) to circulate ink from the ejection port back into the accommodation space. This periodic action maintains ink surface wetness while significantly reducing power consumption compared to continuous operation.
Solution Approach 2:
The patent utilizes the natural vibration characteristics of the piezoelectric element and the hydraulic pressure differences in the system to achieve ink circulation without requiring continuous external power supply. The system leverages the inherent properties of the components and the existing liquid pressure to perform the circulation function intermittently, reducing overall energy consumption while maintaining effectiveness.
2Reliability
If the accommodation space is expanded to circulate ink, then the ink surface drying is suppressed, but the device complexity increases
Solution Approach 1:
The patent merges the circulation function with the existing ink supply and ejection structures. The circulation path utilizes the same accommodation space, ejection port, and piezoelectric element already present in the inkjet system. By combining the circulation function with existing components rather than adding separate dedicated circulation mechanisms, the patent reduces overall device complexity while achieving effective ink surface maintenance.
Solution Approach 2:
The piezoelectric element serves multiple functions: it acts as both the ejection actuator for propelling ink onto the substrate and the circulation actuator for returning ink from the ejection port to the accommodation space. The accommodation space also serves dual purposes as both the ink reservoir and the circulation chamber. This multi-functionality reduces the number of separate components needed, thereby simplifying the overall device structure.
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 solution effectively suppresses ink surface drying while minimizing power consumption by circulating the ink after lowering the water level, eliminating the need for continuous electric power to the piezoelectric element.
Implementation Method 1
a piezoelectric element 30C that vibrates in response to application of a drive voltage
Implementation Method 2
the accommodation space 30B is elevated with respect to the ink supply portion 8
Data Source
AI summary
A liquid ejection device includes an ejection portion, an accommodating portion, a lowering processing portion, and a circulation processing portion. The ejection portion has a first accommodation space configured to accommodate a liquid and eject the liquid from an ejection port communicating with the first accommodation space. The accommodating portion has a second accommodation space below the ejection port and configured to accommodate the liquid to be supplied to the ejection portion, in the accommodating portion, a space above a water level of the liquid accommodated in the second accommodation space communicates with the atmosphere. The lowering processing portion lowers the water level of the liquid accommodated in the accommodating portion with respect to the ejection port. The circulation processing portion circulates the liquid along a circulation path passing through the ejection portion after the water level of the liquid is lowered by the lowering processing portion.