Inkjet Printer Air Pump Protection via Liquid Level Control
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Solution Overview
Problem
Inkjet printing apparatuses with pressurizing and negative-pressure tanks arranged below the inkjet head face issues where vibration can break the meniscus of the nozzle, causing air suction and ink flow into these tanks, potentially leading to air pump failure when ink circulation is initiated with filled tanks.
Innovation Solution
The apparatus includes a control unit that executes preparatory processing by sealing the pressurizing tank and opening the negative-pressure tank to atmosphere, feeding ink from the pressurizing tank to the inkjet head, and then from the negative-pressure tank to the pressurizing tank until the negative-pressure tank's liquid level is below a reference height, preventing ink entry into the air pump and common air chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air pump is driven for ink circulation when the pressurizing tank and negative-pressure tank are filled with ink, then ink circulation can be performed, but the ink enters the air pump and causes breakdown
Solution Approach 1:
The control unit executes preparatory processing before starting ink circulation to lower the liquid level in the negative-pressure tank below the reference height. This preliminary action prevents ink from entering the air pump during subsequent circulation operations, resolving the contradiction between maintaining ink circulation capability and preventing pump damage
Solution Approach 2:
The control unit acts as an intermediary that monitors liquid levels and regulates the timing of air pump operation. By controlling when the air pump operates based on liquid level conditions, the system prevents direct contact between ink and the air pump, thereby protecting the pump while maintaining circulation functionality
2Adaptability or versatility
If vibration occurs during standby, then the meniscus of the nozzle breaks and air is suctioned, but this causes ink to flow down into the tanks and fill them
Solution Approach 1:
The system performs preparatory processing before ink circulation to proactively lower the liquid level in the negative-pressure tank. This preliminary action creates a safety margin that prevents overflow even if vibration causes ink to flow down during standby, allowing the system to adapt to vibration events without compromising tank capacity
3Productivity
If the negative-pressure tank liquid level is high, then ink circulation can be maintained, but ink may be suctioned into the air pump during operation
Solution Approach 1:
The control unit continuously monitors the liquid level in the negative-pressure tank and uses this feedback information to control when the air pump operates. By adjusting air pump operation based on real-time liquid level feedback, the system maintains optimal circulation while preventing ink from being suctioned into the pump
Solution Approach 2:
Before initiating ink circulation, the control unit executes preparatory processing to lower the liquid level below the reference height. This preliminary action establishes safe operating conditions that allow subsequent circulation to proceed efficiently without risking pump contamination
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 risk of air pump failure and ink mixing, maintaining print quality by ensuring the ink circulation starts with the negative-pressure tank's level below the reference height, thus avoiding ink suction and entry into the air pump and common air spaces.
Implementation Method 1
a positive pressure and a negative pressure are applied to the pressurizing tank and the negative-pressure tank, respectively, by feeding air from the negative-pressure tank to the pressurizing tank by the air pump
Implementation Method 2
an ink pump for feeding ink from the negative-pressure tank to the pressurizing tank
Data Source
AI summary
An inkjet printing apparatus includes a control unit which, in order to reduce a failure of an air pump, when starting ink circulation, executes preparatory processing of feeding ink from the pressurizing tank toward the inkjet head by applying a positive pressure to a pressurizing tank by an air pump in a state in which the pressurizing tank is sealed by a pressurizing-side atmospheric air opening valve and a negative-pressure tank is opened to the atmosphere by a negative-pressure side atmospheric air opening valve; and feeding ink from the negative-pressure tank to the pressurizing tank by the ink pump until the liquid level height of the negative-pressure tank reaches less than a reference height.