Ink Viscosity Control via Pressure Feedback in Continuous Inkjet Printers
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Solution Overview
Problem
Continuous inkjet printers face challenges in maintaining optimal ink viscosity due to manufacturing variations and environmental factors, leading to inconsistent print quality and potential blockages, as existing systems fail to account for viscosity changes during operation.
Innovation Solution
A method and system that adjust ink viscosity by measuring pressure differences and using a calibration curve to account for real-time viscosity changes, allowing for dynamic correction through solvent addition or evaporation, ensuring consistent ink quality and print performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ink is supplied continuously to the print head, then printing speed is improved, but ink viscosity varies due to manufacturing tolerances and environmental factors leading to poor print quality
Solution Approach 1:
The system continuously monitors ink viscosity using a viscometer and adjusts the ink supply accordingly. The controller receives viscosity measurements and modifies pump operation or valve positioning to maintain optimal viscosity levels, ensuring consistent print quality despite continuous operation and environmental variations.
Solution Approach 2:
The system dynamically adjusts operational parameters such as pump speed, valve opening degree, or heating temperature based on measured viscosity values. By changing these parameters in response to viscosity variations, the system maintains stable ink flow characteristics and print quality throughout continuous operation.
2Device complexity
If ink viscosity is not monitored, then device complexity is reduced, but blockages occur and print quality becomes inconsistent
Solution Approach 1:
The viscometer provides continuous feedback on ink viscosity to the controller, enabling automatic detection and correction of viscosity deviations. This feedback mechanism prevents blockages by detecting viscosity changes before they cause printing problems, maintaining reliable operation without requiring complex manual monitoring systems.
Solution Approach 2:
The system performs self-monitoring and self-adjustment of ink viscosity through automated viscometry and controller responses. The system serves itself by detecting its own state and making necessary corrections without external intervention, ensuring reliable operation while keeping the overall system design relatively simple.
3Manufacturing precision
If solvent is added to adjust viscosity, then ink quality is improved, but the time required for adjustment increases
Solution Approach 1:
The viscometer provides real-time viscosity measurements that enable immediate detection of quality deviations. The controller can quickly respond by adjusting pump operation or valve positioning to correct viscosity issues, eliminating the need for time-consuming manual solvent addition and restoration operations.
Solution Approach 2:
The system replaces manual mechanical adjustment methods (adding solvent and mechanically stirring) with automated electronic control. The controller uses electronic signals to adjust pump speed or valve positions, achieving viscosity correction much faster than manual methods while improving ink quality consistency.
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 effectively maintains optimal ink viscosity and print quality by dynamically adjusting to changes in viscosity, preventing blockages and ensuring consistent operation of the printer.
Implementation Method 1
an ink circuit in the lower part of the console (zone 4'), that firstly supplies an appropriate quality of ink to the head at a stable pressure, and secondly handles ink output from jets that is not used for printing
Implementation Method 2
The jet is transformed into a regular succession of identically sized drops under the action of a periodic stimulation system (not shown) located upstream from the nozzle outlet
Implementation Method 3
Devices 61 placed along the jet (charge and deflection electrodes) can electrically charge the drops on command and deflect them in an electrical field Ed
Implementation Method 4
They are then diverted from their natural ejection trajectory from the drop generator
Implementation Method 5
Pressure variations occurring in the ink circuit of such a printer can be measured to measure variations of this viscosity
Implementation Method 6
correct the ink viscosity: a) either by allowing solvent in the ink contained in the main reservoir to evaporate for a given time
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a method of adjusting the ink viscosity in an inkjet printer which comprises a fluid circuit (4), a print head (1) connected to the fluid circuit through an umbilical (19), the fluid circuit (4) comprising at least one reservoir (10) called the main reservoir, and a pump (20) to pump ink from this reservoir and send it to said print head (1), an anti-pulse device (23) being located downstream from the pump, along the direction of circulation of ink towards the print head, an ink pressure sensor (24) being located at the outlet from this anti-pulse device (23), this method comprising at least: - the formation of an inkjet, the jet having a velocity equal to or close to a predetermined velocity called the nominal velocity, - a measurement of the ink viscosity while the ink jet is flowing at this nominal velocity, using at least one pressure measurement obtained from the ink pressure sensor (24), - the addition of a quantity of solvent into the ink contained in the reservoir (10), when the viscosity is not equal to a given reference value.