Print Head Humidification via Cross-Flow Gas Supply
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Solution Overview
Problem
Existing inkjet print apparatuses face challenges in suppressing nozzle drying due to high humidity gas supply pressure requirements, leading to increased apparatus size, noise, and ink ejection deviations, as humidified gas takes a long time to reach downstream nozzles and requires high flow resistance.
Innovation Solution
The apparatus supplies humidified gas to a space between adjacent print heads from one side and discharges it from the opposite side, creating a straight airflow that quickly fills the space with minimal channel resistance, reducing the need for high supply pressure and minimizing ink ejection deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If humidified gas is supplied to downstream print heads through sequential flow from upstream, then nozzles are prevented from drying, but the supply time is prolonged and high supply pressure is required
Solution Approach 1:
The patent divides the humidified gas supply system into multiple independent supply units, each responsible for a specific print head or group of print heads. This segmentation allows simultaneous supply to multiple locations rather than sequential flow, reducing total supply time while maintaining effective humidity levels at each nozzle
Solution Approach 2:
The patent introduces intermediate humidified gas supply points between upstream and downstream print heads. These intermediary supply units act as intermediate sources that reduce the distance humidified gas must travel, eliminating the need for long-distance sequential flow and high supply pressure
2Loss of time
If high supply pressure is applied to deliver humidified gas quickly to narrow print gaps, then supply time is reduced, but apparatus size and noise increase
Solution Approach 1:
By segmenting the supply system into multiple lower-power units distributed along the print head array, each unit operates at reduced power levels compared to a single high-power centralized supply. This distributes the power requirement across multiple components, reducing overall apparatus size and noise while achieving quick supply through parallel operation
Solution Approach 2:
The patent transitions from a one-dimensional sequential supply approach (upstream to downstream) to a two-dimensional distributed supply network where multiple supply points operate simultaneously across different locations. This dimensional change allows humidified gas to reach all print heads in parallel without requiring high pressure to force flow through long narrow channels
3Loss of time
If high airflow speed is achieved in narrow print gaps through high supply pressure, then humidified gas reaches nozzles quickly, but ink ejection deviation occurs
Solution Approach 1:
The segmented supply approach creates multiple localized low-speed flow zones rather than one high-speed flow path. Each supply unit generates gentle airflow that suffuses the local print gap without creating high-velocity streams that would disrupt ink ejection, maintaining positioning accuracy while still achieving quick overall coverage through parallel supply
Solution Approach 2:
The patent employs pneumatic diffusion through narrow gaps rather than high-pressure forced flow. By utilizing the natural diffusion and convection properties of gases in confined spaces, humidified gas penetrates the print gaps effectively at low velocities, avoiding the airflow speeds that cause ink droplet deviation while maintaining rapid supply through multiple simultaneous entry points
4Ease of operation
If two ducts (supply and discharge) are disposed in one space between print heads, then gas flow path is established, but channel cross-section area is reduced and channel resistance increases
Solution Approach 1:
The patent extracts the discharge duct function from the same space as the supply duct by utilizing the downstream side of print heads for discharge while supply occurs at upstream sides. This spatial separation eliminates the need to fit both ducts in the same confined space, maintaining full channel cross-section area and minimizing resistance without compromising flow path establishment
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 allows for efficient nozzle humidification in a short time without increasing supply pressure, resulting in a downsized, high-quality printing apparatus with improved throughput.
Implementation Method 1
humidified gas is supplied from a supply port 7 to a space 4 between two adjacent print heads, that is, supplied from one side of the space 4. The gas in the space 4 is discharged from a discharge port 8 which is disposed on the other side facing the supply port 7 in the same space 4
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
Humidified gas generated by a humidifying unit (22) is supplied to a space (4) between two adjacent print heads from one side of the space, and the humidified gas supplied to the space is discharged from the other side facing the one side across the space.