Piezoelectric Print Head Temperature Detection for Ejection Precision
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing liquid ejection apparatuses, such as those described in JP-A-2022-124599, face reduced accuracy in temperature detection of the pressure chamber due to the integration of the temperature detection portion within the print head, which affects the precision of temperature-based ejection control.
Innovation Solution
A liquid ejection apparatus is designed with a temperature detection portion located on one side of the piezoelectric element stacking direction, electrically coupled to a wiring substrate, and detects temperature information during a constant voltage period, with a control circuit inputting this information to adjust ejection control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the temperature detection portion is integrated inside the print head, then the device complexity is reduced, but the temperature detection accuracy deteriorates due to temperature difference between the detected temperature and the pressure chamber temperature
Solution Approach 1:
The temperature detection function is segmented from the print head assembly and placed on the drive circuit board. This allows the detection portion to be spatially separated from the heat-generating piezoelectric elements, reducing thermal interference while maintaining functional integration through electrical coupling.
Solution Approach 2:
A temperature detection portion is introduced as an intermediary component positioned between the heat source (piezoelectric element) and the pressure chamber. This intermediary detects the temperature field without being directly exposed to extreme thermal conditions, enabling accurate temperature measurement for control purposes.
2Measurement precision
If the temperature detection portion is placed close to the pressure chamber to improve detection accuracy, then the temperature detection accuracy improves, but the device complexity increases due to additional components and wiring
Solution Approach 1:
The temperature detection portion is merged with the drive circuit board that already exists in the system. By combining the temperature detection function with an existing structural component, the patent achieves accurate temperature detection without adding separate mounting structures, fasteners, or complex wiring harnesses.
Solution Approach 2:
The drive circuit board serves multiple functions: it provides electrical connections to the piezoelectric elements, supplies drive signals, and now also hosts the temperature detection portion. This multi-functionality eliminates the need for dedicated temperature sensing structures, simplifying the overall device architecture.
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
Enhances the accuracy of temperature detection and ejection control by isolating the temperature detection from the piezoelectric element, improving the precision of liquid ejection based on temperature variations.
Implementation Method 1
a piezoelectric element that includes a first electrode, a second electrode, and a piezoelectric body and in which the piezoelectric body is located between the first electrode and the second electrode in a stacking direction in which the first electrode, the second electrode, and the piezoelectric body are stacked, and that is driven by receiving a first drive signal
Implementation Method 2
a temperature detection portion that is located on the other side of the stacking direction with respect to the vibration plate, is electrically coupled to the wiring substrate, and detects temperature information of the pressure chamber
Data Source
AI summary
A liquid ejection apparatus includes a control circuit that outputs a control signal, a first drive signal output circuit that outputs a first drive signal, and a print head that ejects a liquid, in which the print head includes a piezoelectric element that is driven by receiving the first drive signal, a pressure chamber substrate that is provided with a plurality of pressure chambers of which volumes change due to deformation, a switch circuit that switches whether or not to supply the first drive signal to the piezoelectric element, a wiring substrate that is provided with the switch circuit, and a temperature detection portion that detects temperature information of the first pressure chamber, and the temperature information detected by the temperature detection portion is input to the control circuit in a period in which a voltage value of the first drive signal is constant.