Print Head Temperature Detection Accuracy via Signal Timing
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Solution Overview
Problem
The existing liquid ejection apparatuses, such as those using piezoelectric elements, face challenges in accurately detecting the temperature of the pressure chamber, leading to reduced detection accuracy due to the internal placement of temperature detection components.
Innovation Solution
A liquid ejection apparatus with a print head that includes a piezoelectric element, a vibration plate, pressure chambers, and a temperature detection portion, where the temperature information is detected when the drive signal is not supplied to the piezoelectric element, allowing for improved temperature detection accuracy by separating the temperature detection from the operational cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the temperature detection portion is provided inside the print head, then the structure is compact, but the detection accuracy of the pressure chamber temperature is reduced
Solution Approach 1:
The temperature detection portion is extracted from the internal structure of the print head and relocated to the exterior surface. This allows the detection portion to measure the temperature of the pressure chamber more accurately without being constrained by internal space limitations, while still maintaining a relatively compact overall structure by placing it on the external surface near the pressure chamber.
2Measurement precision
If temperature detection is performed during the drive signal supply period, then the detection is integrated with operation, but the detection accuracy is affected by piezoelectric element operation
Solution Approach 1:
The temperature detection is performed periodically during the period when the drive signal is not being supplied to the piezoelectric element. This periodic detection approach allows the system to measure temperature when the piezoelectric element is at rest, avoiding interference from its operation, while still providing timely temperature information for controlling the ejection operation.
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 in the pressure chamber, leading to more precise control of liquid ejection and improved printing quality by isolating the temperature detection process from the operational cycles of the piezoelectric element.
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 the 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, a drive signal output circuit that outputs a 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 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 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 pressure chamber, and the temperature information detected by the temperature detection portion in a period in which the switch circuit does not supply the drive signal to the piezoelectric element is input to the control circuit.