Liquid Ejecting Head Pressure Control Using Residual Vibration
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Solution Overview
Problem
Existing liquid ejecting apparatuses face challenges in maintaining optimal pressure conditions in the vicinity of nozzles to ensure consistent liquid ejection characteristics, particularly in inkjet printers, due to issues like air bubble retention and liquid thickening.
Innovation Solution
A liquid ejecting apparatus with a piezoelectric element, individual and common flow paths, and pressure applying portions that adjust pressures based on residual vibration detection to optimize ink supply and discharge, using a detection circuit to determine these pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid circulation is implemented in the liquid ejecting head, then air bubble retention and liquid thickening are prevented, but pressure control near the nozzle becomes critical to maintain ejection characteristics
Solution Approach 1:
The patent employs feedback control by detecting residual vibration in the pressure chamber after piezoelectric element actuation and using this information to adjust pressure conditions. The detection portion monitors vibration characteristics, and the pressure determination portion modifies supply and discharge pressures based on detected residual vibration, creating a closed-loop system that maintains stable ejection characteristics while managing the complexity of pressure control.
Solution Approach 2:
The patent replaces direct mechanical pressure measurement and adjustment mechanisms with a vibration-based detection system. Instead of using complex mechanical sensors and actuators to monitor and control pressure near the nozzle, the system uses residual vibration detection from the piezoelectric element to infer pressure conditions and adjusts pressure through control of supply and discharge flow paths, substituting mechanical complexity with vibrational analysis.
2Measurement precision
If residual vibration detection is used to determine pressure, then optimal pressure control is achieved, but additional detection components are required
Solution Approach 1:
The patent applies self-service by utilizing the inherent residual vibration of the pressure chamber after piezoelectric element actuation as the detection signal. The system does not require separate active vibration sources or complex external sensing mechanisms; instead, it leverages the natural vibrational response of the pressure chamber itself to infer pressure conditions, reducing detection system complexity while maintaining measurement precision.
Solution Approach 2:
The piezoelectric element serves multiple functions: it acts as both the actuator for liquid ejection and the source of vibration for pressure detection. The pressure chamber similarly serves dual purposes as both the liquid containment space and the vibration sensing element. This multi-functionality reduces the need for separate detection components, lowering device complexity while achieving accurate pressure measurement through residual vibration analysis.
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 ensures stable and efficient ink ejection by maintaining optimal pressure conditions, preventing air bubble retention and liquid thickening, thereby enhancing the reliability and quality of printed images.
Implementation Method 1
a piezoelectric element; a plurality of individual flow paths each including a nozzle N and a pressure chamber CV; a detection circuit 19 that detects residual vibration in the pressure chamber CV after a voltage is applied to the piezoelectric element PZ
Implementation Method 2
a detection portion that detects residual vibration in the pressure chamber after a voltage is applied to the piezoelectric element
Data Source
AI summary
A liquid ejecting apparatus includes a pump that applies a pressure for supplying the ink to the common flow path to the common flow path, a pump that applies a pressure for discharging the ink from the other common flow path to the other common flow path, a detection circuit that detects residual vibration in the pressure chamber after applying a voltage to the piezoelectric element, and a circulation control portion that determines the pressure for supplying the ink and the pressure for discharging the ink based on the residual vibration detected by the detection circuit.