Liquid Discharge Head Stabilization via Coercive Field Control
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Solution Overview
Problem
The liquid discharge head with an electromechanical transducer actuator in a flexural vibration mode experiences unstable liquid discharge characteristics, particularly at the initial stage of operation, due to significant fluctuations in the displacement of the electromechanical transducer element, which affects the discharge amount and speed.
Innovation Solution
A liquid discharge head is designed with a characteristic fluctuation suppressor that applies a specific voltage waveform between drive waveforms, set to be larger than the negative coercive electric field but smaller than the positive coercive electric field of the electromechanical transducer film, to stabilize the fluctuations and prevent discharge during this period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an electromechanical transducer actuator with flexural vibration mode is used, then the liquid discharge head can be formed by a simple film formation technology and lithography method, but the displacement of the electromechanical transducer element fluctuates significantly, causing unstable liquid discharge characteristics
Solution Approach 1:
The patent applies preliminary action by performing a polarization processing step before actual liquid discharge operation. This involves applying a high voltage and high frequency drive signal with predetermined pulse number to the electromechanical transducer element to stabilize its polarization state, thereby reducing displacement fluctuations and improving liquid discharge characteristic stability before normal operation begins
2Reliability
If a higher voltage and higher frequency drive signal is applied for polarization processing, then the electromechanical transducer element polarization state is stabilized, but the energy consumption increases
Solution Approach 1:
The patent applies periodic action by using a drive signal with predetermined pulse number for polarization processing. The periodic high voltage and high frequency signals are applied for a specific duration to stabilize the electromechanical transducer element, after which normal operation proceeds with reduced energy 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 effectively suppresses characteristic fluctuations in the electromechanical transducer element, leading to stable and consistent liquid discharge performance even after repeated driving, as demonstrated by the evaluation results showing minimal change in discharge speed over a large number of cycles.
Implementation Method 1
extension or contraction occurs effectively in accordance with increase or decrease of an electric field application intensity when a vector component of a spontaneous polarization axis of the electromechanical transducer film is equal to an electric field application direction
Implementation Method 2
The characteristic fluctuation suppressor applies a characteristic fluctuation suppression voltage to suppress characteristic fluctuation of the electromechanical transducer element in a section between a drive waveform applied to the electromechanical transducer element and a subsequent drive waveform
Data Source
AI summary
A liquid discharge head includes a nozzle plate, a diaphragm, an electromechanical transducer element, and a characteristic fluctuation suppressor. The nozzle plate has a nozzle orifice communicated with a chamber to discharge a discharge liquid stored in the chamber. The diaphragm divides a part of the chamber. The transducer element is disposed on the diaphragm and includes a lamination of a lower electrode, an electromechanical transducer film, and an upper electrode. The suppressor applies a characteristic fluctuation suppression voltage to suppress characteristic fluctuation of the transducer element in a section between a drive waveform applied to the transducer element and a subsequent drive waveform. The suppressor sets the suppression voltage to be larger than a negative coercive electric field of the transducer film and smaller than a positive coercive electric field of the transducer film and have a waveform that does not discharge the liquid in the chamber.