Liquid Ejecting Apparatus Drive Signal Periodic Action
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Solution Overview
Problem
Ink jet printers face issues with ink ejection stability due to alternating current components in drive signals, leading to decreased image quality and increased power consumption, as well as the occurrence of sub-satellite ink droplets during head driving.
Innovation Solution
A liquid ejecting apparatus with a specific signal processing system that generates a drive signal with defined intervals for pressure chamber expansion and contraction, where the period of the alternating current component is a common divisor of the intervals, and uses a voltage comparator with triangular or saw-tooth wave comparison signals to suppress waveform reproducibility issues and prevent sub-satellite ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pulse modulation is used to generate drive signals for ink ejection, then the liquid ejecting apparatus can be controlled to eject liquid, but alternating current components are introduced that decrease ink ejection stability and increase power consumption
Solution Approach 1:
The patent applies periodic action by introducing a delay component that creates a periodic structure in the drive signal timing. The delay time is set to be an integer multiple of the period of the alternating current component, causing the alternating current to complete full cycles during the delay period. This periodic alignment causes the alternating current components to cancel each other out through constructive and destructive interference, thereby eliminating them from the final drive signal and improving ink ejection stability.
2Ease of operation
If pulse modulation is used to generate drive signals, then liquid ejection can be controlled, but sub-satellite ink droplets are ejected due to meniscus recovery, decreasing image quality
Solution Approach 1:
The patent uses periodic action by setting the delay time to be an integer multiple of the alternating current period. This causes the alternating current components to complete full cycles during the delay period, canceling each other out. By eliminating these alternating current components, the drive signal becomes cleaner and more precise, preventing meniscus recovery and sub-satellite droplet ejection, thereby improving image quality.
3Power
If switching elements are used to amplify the modulation reference drive signal, then the drive signal can be amplified, but switching losses increase power consumption
Solution Approach 1:
The patent applies periodic action by introducing a delay component that creates periodic timing relationships with the alternating current components. The delay time being an integer multiple of the alternating current period causes the switching elements to operate at optimal times, minimizing switching losses. This periodic alignment ensures that switching events occur when the signal is at appropriate voltage levels, reducing the energy required for switching and thereby lowering overall power consumption.
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 enhances ink ejection stability, prevents sub-satellite formation, and reduces power consumption by optimizing the waveform reproducibility and switching losses in the drive signal.
Implementation Method 1
a piezoelectric element that deforms in response to the drive signal, a pressure chamber that expands and contracts due to the deformation of the piezoelectric element
Implementation Method 2
a pressure chamber that expands and contracts due to the deformation of the piezoelectric element, and has a Helmholtz resonance frequency of a period Tc, and a nozzle opening portion that communicates with the pressure chamber and ejects a liquid
Implementation Method 3
a pressure chamber that expands and contracts due to the deformation of the piezoelectric element, and has a Helmholtz resonance frequency of a period Tc
Data Source
AI summary
A liquid ejecting apparatus includes a reference drive signal generation section that generates a reference drive signal, a signal modulation section that modulates the reference drive signal to generate a modulation reference drive signal, a signal amplification section that amplifies the modulation reference drive signal using switching elements to generate a modulation drive signal, a signal conversion section that converts the modulation drive signal to a drive signal, and a head which includes a piezoelectric element that deforms in response to the drive signal, a pressure chamber that expands and contracts due to the deformation of the piezoelectric element and has a Helmholtz resonance frequency of a period Tc, and a nozzle opening portion that communicates with the pressure chamber. A period of an alternating current component contained in the modulation drive signal is a divisor of a section of one of the drive signal.