Segmented Inkjet Flow Paths for Air and Solid Matter Purging
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Solution Overview
Problem
Inkjet recording apparatuses face challenges in maintaining high print quality due to residue of air and solid matter inside the negative pressure regulation valve, which can lead to bubble inflow into the nozzle, affecting ink ejection.
Innovation Solution
The apparatus incorporates a negative pressure regulation valve with an inflow-side and outflow-side pressure chamber, a communication hole, and a movable valve member to regulate pressure, allowing efficient discharge of air and solid matter during a suction purge process, preventing bubble entry into the nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a negative pressure regulation valve is used to regulate pressure in the ink flow path, then ink ejection stability is improved, but air and solid matter residue occurs inside the valve
Solution Approach 1:
The outflow-side pressure chamber is segmented into multiple outflow paths (first outflow path to recording head, second outflow path to cap/waste ink discharge) with outflow holes positioned at different heights. This segmentation allows different substances (ink, air, solid matter) to be discharged through different paths based on their density and position, preventing residue while maintaining pressure regulation function.
Solution Approach 2:
Air and solid matter are extracted from the ink flow path through the second outflow path that leads to the cap and waste ink discharge path. The opening/closing valve selectively opens this path during suction purge to remove harmful substances (air bubbles and solid matter residue) from the outflow-side pressure chamber, preventing them from entering the recording head.
2Object-generated harmful factors
If the suction pump sucks air from the inside of the cap, then air residue is reduced, but bubbles may be suctioned into the nozzle
Solution Approach 1:
The negative pressure regulation valve acts as an intermediary between the ink container and recording head. During suction purge, it allows air to be removed from the cap while preventing bubbles from reaching the nozzle by directing them through the second outflow path to waste ink discharge, thus mediating between air removal and bubble prevention.
Solution Approach 2:
The opening/closing valve is opened in advance before the suction pump operates, establishing the second outflow path to the cap and waste ink discharge path. This preliminary action ensures that when the suction pump runs, air and bubbles are directed through the predetermined path to waste discharge rather than into the recording head nozzle.
3Productivity
If the opening/closing valve opens the second outflow path during suction purge, then air and solid matter are discharged efficiently, but ink flow to recording head is interrupted
Solution Approach 1:
The opening/closing valve dynamically changes its state based on operational requirements. During suction purge, it opens to allow efficient discharge of air and solid matter through the second outflow path. During normal printing, it closes to ensure all ink flows through the first outflow path to the recording head. This dynamic switching resolves the contradiction between purge efficiency and ink flow continuity.
Solution Approach 2:
The opening/closing valve operates periodically - opening during suction purge cycles to discharge air and solid matter, then closing during normal printing operations to maintain ink flow. This periodic switching between purge mode and printing mode allows efficient removal of harmful substances while ensuring continuous ink supply during printing.
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 configuration effectively suppresses air and solid matter residue, ensuring stable ink ejection and improved print quality by efficiently purging the system, reducing the risk of bubble entry and maintaining optimal ink flow.
Implementation Method 1
a suction pump that sucks air from an inside of the cap
Implementation Method 2
The suction pump sucks air from an inside of the cap
Implementation Method 3
a valve member that is inserted in the communication hole and movable, in accordance with change of pressure inside the outflow-side pressure chamber, to a closing position for closing the communication hole and an opening position for opening the communication hole
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An inkjet recording apparatus (100) includes an ink container (30), one or more recording heads (17), an ink flow path (40), a negative pressure regulation valve (31), a cap (201), a suction pump (45), and a waste ink discharge path (47). The negative pressure regulation valve (31) includes an inflow-side pressure chamber (50), an outflow-side pressure chamber (51), a communication hole (54), a first outflow hole (51a) and a second outflow hole (51b) respectively formed in the outflow-side pressure chamber (51) so as to be below and above the communication hole (43), and respectively communicating with the first outflow path (42) and the second outflow path (43), and a valve member (52) that opens and closes the communication hole (54). The first outflow path (42) communicates with the recording heads (17). The second outflow path (43) communicates with an inside of the cap (201) or a waste ink discharge path (47), and is provided with an opening/closing valve (44).