Electrohydrodynamic Print Head Feed Structure for Homogeneous Ink and Gas Flow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrohydrodynamic inkjet printing systems face challenges in maintaining homogeneous flows of gas and ink over the print head, leading to uneven drying and deposition of ink on the target.
Innovation Solution
The print head design includes a configuration with ink nozzles arranged in rows and columns, surrounded by ventilation openings, and a network of ink and gas feed/withdrawal ducts that ensure uniform distribution of fluids, using a manifold structure to maintain consistent flow patterns and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ventilation ducts are provided at the ink nozzles to feed dry gas, then ink drying is expedited, but the feed structure becomes complex and flow homogeneity is difficult to maintain
Solution Approach 1:
The print head is divided into an active region containing ink nozzles and a passive region containing ventilation openings. This segmentation allows independent optimization of ink ejection and gas feeding functions, simplifying the overall feed structure while maintaining efficient ink drying through the passive region's ventilation system.
Solution Approach 2:
A gas distribution channel acts as an intermediary structure that connects the ventilation openings in the passive region to the active region. This intermediary enables uniform gas distribution across the ink nozzles without requiring direct complex connections at each nozzle, thereby simplifying the feed structure while maintaining flow homogeneity.
2Stability of the object's composition
If ventilation openings are arranged in the passive region, then gas flow homogeneity is improved, but the device structure becomes more complex
Solution Approach 1:
The print head is designed with different functional zones: the active region for ink ejection and the passive region for gas feeding. By localizing ventilation openings to the passive region and using a gas distribution channel, the structure achieves uniform gas flow distribution without requiring complex arrangements throughout the entire device, thus improving flow homogeneity while controlling structural complexity.
3Stability of the object's composition
If ink feed ducts are extended to reach all nozzles, then ink flow homogeneity is improved, but flow resistance increases
Solution Approach 1:
The ink feed system is segmented into a bulk ink feed duct and multiple ink feed slit vias. The bulk duct receives ink from the ink source and distributes it to multiple slit vias, which then feed individual rows of nozzles. This segmentation reduces the length of individual ducts and minimizes flow resistance while maintaining homogenous ink flow distribution across all nozzles.
Solution Approach 2:
The ink feed system transitions from a single-dimensional long duct to a multi-dimensional distribution network involving bulk ducts and slit vias arranged in parallel. This dimensional change allows ink to reach multiple nozzles through shorter, parallel pathways, reducing flow resistance while maintaining flow homogeneity.
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 design achieves a more homogeneous flow of ink and gas, enhancing the uniformity of ink deposition and drying on the target, improving the printing process efficiency.
Implementation Method 1
The nozzles are adapted to eject ink from the print head by means of electrical fields. Typically, each nozzle comprises an ink retainer to provide ink at a defined location and an ejection electrode to eject ink from the ink retainer.
Implementation Method 2
The ventilation openings are used to feed dry gas to the space between the print head and the target and/or to carry of gas from this space.
Implementation Method 3
Ink feed ducts connecting the ink feed terminal to the nozzles: The ink feed ducts are adapted to guide the ink from the ink feed terminal to the nozzles.
Implementation Method 4
using a manifold structure to maintain consistent flow patterns and reduce resistance
Data Source
AI summary
The electrohydrodynamic print head includes ink nozzles as well as blow openings for dry gas and suction openings at its front side. In addition, humid gas is fed through the print head to the nozzles. The front side has an elongate active region surrounded by a passive region, with all the ink nozzles being arranged in the active region. The blow and suction openings are arranged in the active and the passive regions such that the active region is surrounded by ventilation openings. Ink feed slit vias beneath the rows of the nozzles provide a homogenous ink supply. In one of the bottom layers of the print head, bulk feed and withdrawal ducts distribute the fluids to smaller ducts above them. Manifolds are provided in the print head in order to homogenize the feed and withdrawal of the fluids. Manifolds are used to further homogenize with fluid flows.