Piezoelectric Liquid Ejecting Head Self-Heating Control
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Solution Overview
Problem
Existing liquid ejecting heads require complex configurations with temperature detection elements to ensure normal ejection, which can be unreliable without accurate temperature detection, leading to potential image quality deterioration.
Innovation Solution
A liquid ejecting head with a pressure chamber, nozzle, and piezoelectric element that employs preliminary heating steps to heat and eject liquid, allowing for normal ejection without temperature detection, using the driving IC and wiring to generate heat and stir the liquid, thus simplifying the configuration and ensuring reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature detection element is provided to detect the temperature of liquid in the pressure chamber, then it is possible to determine whether normal liquid ejection is possible, but the configuration of the liquid ejecting head becomes complex
Solution Approach 1:
The piezoelectric element serves dual functions: it acts as the actuator for liquid ejection and simultaneously as a heating element for temperature control. The driving IC generates heat as a byproduct during operation, which is utilized to heat the liquid in the pressure chamber. This self-service approach eliminates the need for separate temperature detection and heating components, resolving the contradiction between reliability and device complexity.
2Reliability
If temperature detection means is used to detect the temperature of liquid in the pressure chamber, then it is possible to control heating, but accurate temperature detection is difficult and may lead to image quality deterioration
Solution Approach 1:
The system implements feedback control by monitoring the ejection state of liquid droplets. When droplets are properly ejected, it indicates the liquid temperature is appropriate. This feedback mechanism replaces direct temperature measurement with indirect observation of ejection performance, eliminating measurement precision issues while maintaining reliable temperature control.
Solution Approach 2:
The piezoelectric element and driving IC automatically generate heat during normal operation, providing self-heating functionality. This eliminates the need for external heating control systems and complex temperature sensing, as the system self-regulates temperature through its operational heat generation.
3Reliability
If idle ejection is performed to return the liquid ejecting head to normal operation state, then liquid ejection can be restored, but additional operation steps are required
Solution Approach 1:
The system performs preliminary heating of the liquid in the pressure chamber using the piezoelectric element and driving IC before idle ejection. This preliminary action prevents liquid thickening and meniscus drying from occurring in the first place, allowing the head to maintain normal ejection capability without requiring additional recovery steps, thus reducing time loss.
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 configuration enables reliable liquid ejection by heating the liquid to a suitable temperature for printing without temperature detection, improving the reliability of the liquid ejecting head and simplifying its design, while maintaining image quality.
Implementation Method 1
a piezoelectric element which is provided in a vibrating plate closing a portion of the pressure chamber and which generates pressure fluctuations in a liquid in the pressure chamber by causing the vibrating plate to vibrate
Implementation Method 2
a first preliminary heating step of heating the liquid in the pressure chamber by causing at least any one of the piezoelectric element, the driving IC, and the wiring to generate heat
Data Source
AI summary
A liquid ejecting head includes a pressure chamber; a nozzle communicating with the pressure chamber; a piezoelectric element which generates pressure fluctuations in a liquid in the pressure chamber; and a driving IC which is connected to the piezoelectric element through wiring and which carries out driving control of the piezoelectric element, in which the driving control has a first preliminary heating step of heating the liquid in the pressure chamber, a preliminary ejection step of ejecting a liquid in the pressure chamber from the nozzle after the first preliminary heating step, a second preliminary heating step of heating the liquid in the pressure chamber more weakly than in the first preliminary heating step after the preliminary ejection step, and a main ejection step of starting an operation of ejecting the liquid from the nozzle after the second preliminary heating step.