Inkjet Print Head Suction Control via Two-Stage Negative Pressure
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Solution Overview
Problem
Ink jet printing apparatuses face challenges in optimizing suction recovery to fill ink into the print head while removing bubbles from the ink ejection nozzle section, with existing pumps either discharging too much ink or struggling to adjust the suction amount accurately.
Innovation Solution
The apparatus employs a pump with a valve that generates negative pressure in two stages, first under low pressure and then high pressure, allowing precise control of ink suction by opening and closing the valve to manage the suction process effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tube pump increases negative pressure to remove bubbles from the ink ejection nozzle section, then bubble removal is improved, but the amount of ink discharged from the print head increases excessively
Solution Approach 1:
The suction recovery process is divided into two distinct stages: a first suction process at lower negative pressure to fill ink into the ink path and common liquid chamber, and a second suction process at higher negative pressure to remove bubbles from the ink ejection nozzle section. This segmentation allows each process to operate under optimized pressure conditions, preventing excessive ink discharge while ensuring complete bubble removal.
Solution Approach 2:
The negative pressure level is dynamically adjusted between the two suction processes. The control unit varies the negative pressure from the first level during the first suction process to a second, higher level during the second suction process. This dynamic adjustment enables the system to adapt to different requirements of ink filling versus bubble removal, resolving the contradiction between reliable bubble removal and minimizing ink loss.
2Reliability
If the piston pump sets high initial negative pressure to remove bubbles, then bubble removal is improved, but the suction amount cannot be adjusted accurately for filling ink into the ink path
Solution Approach 1:
The suction recovery process is segmented into two stages with different pressure levels. The first suction process uses lower negative pressure optimized for filling ink into the ink path and common liquid chamber, while the second suction process uses higher negative pressure for removing bubbles. This segmentation provides accurate control over the suction amount for ink filling, overcoming the limitation of piston pumps that cannot adjust suction amount accurately.
Solution Approach 2:
The negative pressure parameter is changed between the two suction processes. The control unit adjusts the negative pressure level from the first level during ink filling to a second, higher level during bubble removal. This parameter change enables the system to optimize both processes separately, providing accurate suction amount control for ink filling while maintaining effective bubble removal.
3Quantity of substance
If the tube pump continuously increases negative pressure to ensure complete ink filling, then ink filling is improved, but the amount of ink sucked increases excessively
Solution Approach 1:
The suction recovery process is divided into two distinct stages: first suction at lower negative pressure to fill ink into the ink path and common liquid chamber, and second suction at higher negative pressure to remove bubbles. This segmentation allows the system to achieve complete ink filling without excessively increasing negative pressure continuously, thereby minimizing ink loss while ensuring adequate ink supply.
Solution Approach 2:
The negative pressure is dynamically adjusted in two steps rather than continuously increased. The control unit first establishes a lower negative pressure level for ink filling, then increases it to a higher level for bubble removal. This dynamic adjustment in two stages ensures complete ink filling while preventing excessive ink discharge that would result from continuous pressure increase.
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 reduces the amount of ink sucked from the print head, enhancing the reliability of the print head while efficiently removing bubbles, thus improving printing performance and reducing waste ink volume.
Implementation Method 1
a pump which presses the tube, said suction means sucking ink from the print head by generating negative pressure in the cap by the pressing of the pump
Data Source
AI summary
An ink jet printing apparatus includes a print head having an ejection port surface with ejection ports formed therein from which ink is ejected, a cap covering the ejection port surface of the print head, and a suction unit for allowing a pump to generate negative pressure in the cap to suck ink from the print head. The suction unit has a valve provided in a communication tube joining the pump and the cap together. The suction unit sucks ink under a relatively low negative pressure and then switches the valve to suck the ink under a relatively high negative pressure.