Inkjet Print Head Maintenance Using Negative Pressure Recirculation
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Solution Overview
Problem
Inkjet recording apparatuses face inefficiencies in reflow maintenance due to wasteful ejection of ink during nozzle clogging removal, as the pressure used to guide ink to the recovery passage also causes ink to be ejected from the nozzle, leading to ink wastage.
Innovation Solution
The apparatus includes a control unit that manages a negative pressure state in the second storage section, using switching units to isolate gas entrances and exits, and a recovery passage to guide ink back to the second storage section, reducing ink ejection and enhancing reflow maintenance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If pressure is applied to guide ink to the recovery passage during reflow maintenance, then ink can be recovered from the recording head, but ink is also ejected from the nozzle wastefully
Solution Approach 1:
The invention divides the storage system into two separate storage sections: a first storage section that supplies ink to the recording head, and a second storage section that receives recovered ink from the recording head. This segmentation allows independent pressure control for ink supply and ink recovery, preventing the conflict where pressure needed for recovery causes unwanted ejection from nozzles.
Solution Approach 2:
The invention introduces a recovery passage as an intermediary pathway that connects the recording head to the second storage section. This separate recovery pathway allows ink to be guided back to storage without passing through the nozzle ejection path, enabling recovery operations without causing wasteful ink ejection from the nozzles.
2Loss of substance
If pressure is used to extrude ink to the recovery passage, then ink can be recovered, but the force is wasted ejecting ink from the nozzle
Solution Approach 1:
The pressure control system is segmented into independent control mechanisms: a supply unit that controls pressure for ink supply to the recording head, and a recovery passage that utilizes pressure differential (negative pressure) for ink recovery. This segmentation allows optimized pressure utilization in each pathway, preventing energy waste from conflicting pressure requirements.
Solution Approach 2:
Instead of applying positive pressure to force ink into the recovery passage, the invention inverts the approach by applying negative pressure (suction) to draw ink into the recovery passage and second storage section. This inversion of pressure direction enables efficient ink recovery without causing unwanted ejection from the nozzles.
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 minimizes ink wastage and improves the effectiveness of reflow maintenance by using suction force to guide ink into the recovery passage without ejecting it from the nozzle, thereby reducing ink consumption during maintenance.
Implementation Method 1
allows the inside of the second storage section to enter a negative pressure state by discharging gas inside the second storage section
Implementation Method 2
supplying the ink stored in the second storage section to the first storage section, and allowing ink inside the recording head to reflow to the second storage section
Data Source
Figure 1~2
Figure 3A
Figure 3B
AI summary
The present invention reduces the amount of ink discharged and performs more efficient recirculating maintenance. The inkjet printing device is provided with: print heads (241) having multiple nozzles (N); first pooling sections (242) for pooling ink to be supplied to the print heads (241); supply paths (301) for connecting the print heads (241) with the first pooling sections (242); electromagnetic valves (310) for opening or tightly sealing the first pooling sections (242); a second pooling section (243) for pooling ink to be supplied to the first pooling sections (242); pumps (P1) for supplying the ink in the second pooling section (243) to the first pooling sections (242); an electromagnetic valve (312) for opening or tightly closing the second pooling section (243); collection paths (302) connecting the print heads (241) to the second pooling section (243); electromagnetic valves (307, 308) for opening and closing the collection paths (302); and a control unit (40) for operating the pumps (PI) when the electromagnetic valves (310, 312) are closed and the electromagnetic valves (308) are open to recirculate ink inside the print heads (241) to the second pooling section (243).