Print Head Actuation Signal Strategy for Air Leakage Prevention
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Solution Overview
Problem
High-speed print systems face productivity loss and ink wastage due to epidemic failures of print elements caused by underpressure leading to air leakage, which necessitates time-consuming maintenance procedures.
Innovation Solution
A method of actuating ink discharge elements in a print head by determining a ratio of non-discharging signals to null signals, increasing with the number of discharging signals, and applying non-discharging signals randomly to elements not generating ink drops to prevent air leakage, thereby maintaining high productivity without ink loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-discharging signals are applied to all non-active elements, then air leakage is prevented, but energy is wasted and temperature increases
Solution Approach 1:
The patent applies different signal types to different elements based on their operational state. Active elements receive discharging signals, while non-active elements receive null signals rather than non-discharging signals. This localized differentiation prevents energy waste in elements that don't require pressure maintenance, while still preventing air leakage in elements that need periodic activation.
Solution Approach 2:
The patent implements preliminary action by periodically activating non-active elements with null signals before they are needed. This prevents air leakage and maintains readiness without requiring continuous non-discharging signals, thus avoiding unnecessary energy dissipation while ensuring reliability when elements are actually used.
2Loss of energy
If null signals are applied to non-active elements, then energy is saved, but air leakage occurs causing epidemic failures
Solution Approach 1:
The patent applies null signals as a preliminary action to non-active elements before they are needed. This periodic activation prevents air leakage and maintains element readiness without requiring continuous energy input, thus preventing epidemic failures while minimizing energy consumption compared to continuous non-discharging signals.
3Reliability
If maintenance procedures are performed frequently, then print element failures are prevented, but productivity decreases
Solution Approach 1:
The patent implements preliminary action by periodically activating non-active elements with null signals during normal operation. This prevents air leakage and epidemic failures before they occur, eliminating the need for frequent maintenance interruptions and keeping the print system running at full productivity throughout the print run.
4Reliability
If non-discharging signals are applied continuously, then air leakage is prevented, but ink pressure chamber pressure fluctuations increase
Solution Approach 1:
The patent applies different signal strategies to different elements: discharging signals to active elements and null signals to non-active elements. This localized approach prevents air leakage in elements that need it while avoiding unnecessary pressure fluctuations in elements that are not currently in use, thus maintaining both reliability and pressure stability.
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
The method effectively postpones or eliminates print element failures by preventing air ingress into non-active elements, maintaining high productivity and reducing ink wastage, especially during long runs with high ink coverage.
Implementation Method 1
Each of the elements further comprises an actuator that converts an electric signal into a mechanical displacement, thus either expanding or contracting an ink pressure chamber
Implementation Method 2
If the electric signal is sufficiently large, an ink drop is created at an end of the nozzle of the print element
Implementation Method 3
a non-discharging signal that causes a pressure wave in the ink pressure chamber of an element without generating a drop from the corresponding nozzle
Data Source
Figure 1~2
Figure 3~4
AI summary
A method is provided for actuating an liquid discharge element in an array of discharge elements of a print head. The liquid is provided to the elements of the array through a channel in the print head. A discharge element is provided with a driving signal from a set of signals comprising a discharging signal, a non-discharging signal, and a null signal. Only the first signal generates a drop of liquid, the second and third do not. An amount of discharging signals supplied to the print head is determined in accordance with a required number of droplets. A ratio of non-discharging signals versus null signals for the elements that do not discharge a drop of liquid increases with increasing amount of discharging signals. The elements receiving an non-discharge signal are selected randomly from the elements not discharging a drop of liquid. This extends the time that the print head may be operated without maintenance.