Continuous Inkjet Gutter Pump Noise Monitoring
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Solution Overview
Problem
Continuous inkjet printers face challenges in minimizing solvent consumption during the process of returning ink and air to the printer housing, with existing methods requiring fine balances, being prone to contamination, or causing unreliability due to air/ink mixture drying on valves.
Innovation Solution
A method of controlling the flow of ink and air through the gutter line by monitoring noise generated in the gutter line to adjust the operation of the gutter pump, ensuring operation within the transition flow regime that balances ink removal with minimal airflow, thereby reducing solvent consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If air is recirculated back to the printhead to reduce solvent consumption, then solvent loss is minimised, but the ink reservoir tank becomes over-pressured
Solution Approach 1:
The patent extracts a portion of the recirculated air flow from the closed loop system and vents it to atmosphere through a controlled outlet. This prevents over-pressurization of the ink reservoir while maintaining sufficient air recirculation to minimize solvent consumption. The extraction of excess air from the system resolves the contradiction between solvent conservation and pressure management.
Solution Approach 2:
The patent changes the flow rate parameter of the recirculated air by introducing a controlled vent outlet. By adjusting the vent opening degree or venting area, the system optimizes the balance between maintaining adequate air circulation for solvent recovery and preventing reservoir over-pressurization. This parameter adjustment resolves the contradiction dynamically.
2Productivity
If a valve is placed in the gutter line to control airflow, then ink clearance is improved, but the air/ink mixture dries on the valve causing unreliability
Solution Approach 1:
The patent replaces the mechanical valve system with a vacuum pump-based flow control system. Instead of using a valve that requires mechanical movement and is prone to sticking from dried ink, the system uses a vacuum pump to create negative pressure that actively draws air and ink through the gutter line. This substitution eliminates the reliability issue associated with valves while maintaining effective ink clearance.
Solution Approach 2:
The patent employs pneumatic principles by using vacuum pressure to control airflow through the gutter line. The vacuum pump creates a pressure differential that drives the air/ink mixture through the system without requiring mechanical valves. This pneumatic control method improves reliability by eliminating moving parts that can stick, while still achieving effective ink clearance.
3Productivity
If airflow through the gutter line is increased to clear ink, then ink removal is improved, but solvent consumption increases
Solution Approach 1:
The patent implements a feedback control system that monitors gutter line conditions (such as ink presence or flow characteristics) and dynamically adjusts the vacuum pump operation or vent opening to optimize airflow. This feedback mechanism ensures that sufficient airflow is maintained for effective ink clearance while minimizing excess airflow that would increase solvent evaporation, thus resolving the contradiction between clearance effectiveness and solvent conservation.
Solution Approach 2:
The patent applies partial action by venting only the necessary portion of air to atmosphere while recirculating the remainder back to the printhead. This partial venting approach provides just enough airflow to clear ink effectively from the gutter line without creating excessive airflow that would lead to unnecessary solvent evaporation. The selective application of airflow resolves the contradiction between adequate ink clearance and minimal solvent loss.
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 ensures reliable operation with reduced solvent consumption by maintaining effective ink clearance and preventing substrate damage, while compensating for variations in environmental conditions and printer tolerances.
Implementation Method 1
Ink, together with entrained air, is generally returned to the printer housing under vacuum, the vacuum being generated by a pump in the gutter line.
Implementation Method 2
WO 93/17869 discloses the use of a Peltier device in a ventilation outlet from an ink reservoir, the Peltier device condensing volatile organic solvents passing from the reservoir through the vent.
Implementation Method 3
The condenser has a first cold surface at the dew point of water to remove water vapour, and a second cooler surface to remove solvent from the vapour.
Implementation Method 4
A vibration or perturbation is applied to the inkjet causing the jet to break into a stream of droplets.
Implementation Method 5
an electrostatic facility to deflect the charged droplets away from their original trajectory and onto a substrate
Implementation Method 6
a pump in the gutter line
Data Source
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AI summary
The invention discloses various methods of controlling or monitoring the performance of a continuous inkjet printer based on monitoring vacuum levels and/or noise in the gutter line.