Liquid Ejection Head Pulse Timing for Vibration Control
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Solution Overview
Problem
Existing liquid ejection heads face challenges in achieving high printing speeds and stable droplet ejection while expanding the gradation expression range and suppressing residual vibration.
Innovation Solution
A liquid ejection head design that includes a nozzle, a pressure chamber, an actuator to change the pressure chamber volume based on a voltage signal, and a drive circuit generating a voltage signal with specific ejection pulses and intervals to stabilize droplet ejection and expand gradation expression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple ejection pulses are applied to eject multiple droplets, then productivity is improved, but residual vibration increases and ejection stability deteriorates
Solution Approach 1:
The patent applies periodic action by spacing ejection pulses at intervals of 0.8λ to 1.2λ, where λ is the period of primary natural vibration of the pressure chamber. This periodic spacing prevents resonance and suppresses residual vibration while enabling multiple droplet ejections, thereby improving both productivity and ejection stability simultaneously
2Ease of manufacture
If ejection pulses are applied at regular intervals, then manufacturing is simplified, but gradation expression range is limited
Solution Approach 1:
The patent applies dynamics by making the ejection pulse interval adjustable within the range of 0.8λ to 1.2λ rather than fixed at a single value. This dynamic adjustment capability allows optimization for different printing conditions and droplet sizes while maintaining a relatively simple control structure, thereby expanding gradation expression range without significantly complicating manufacturing
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 solution stabilizes ink droplet ejection, widens the range for increasing or decreasing droplet size, and suppresses residual vibration, thereby enhancing printing performance and gradation expression.
Implementation Method 1
an actuator configured to change a volume of the pressure chamber according to a voltage signal applied to the actuator
Data Source
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AI summary
A liquid ejection head includes a nozzle for ejecting a droplet of a liquid, a pressure chamber connected to the nozzle, an actuator for changing a volume of the chamber according to a voltage signal, and a drive circuit generating the signal for ejecting n droplets, where n is an integer of 3 or more. The signal includes (n-1) ejection pulses, comprising a first pulse lowering the voltage signal to a first value to expand the chamber and then to a second value to contract the chamber, and a second pulse lowering the voltage signal to the first value and then to a third value higher than the second value. The pulses are input at intervals of 0.8λ to 1.2λ, where λ is a primary natural vibration period of the chamber filled with the liquid.