Liquid Ejection Apparatus Ink Circulation Detection Without Pressure Sensor
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Solution Overview
Problem
Existing liquid ejection apparatuses face challenges in reducing size and cost while effectively monitoring ink circulation flow, particularly due to the inclusion of pressure sensors in the circulation path.
Innovation Solution
A liquid ejection apparatus that includes a print unit, a pump for circulating liquid, and a control unit. The control unit operates the pump using different outputs during printing and circulation testing, allowing for the detection of normal ink circulation flow without the need for a pressure sensor in the circulation path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure sensor is installed in the circulation path to monitor ink circulation flow, then the reliability of circulation detection is improved, but the device complexity and cost increase
Solution Approach 1:
The patent removes the pressure sensor from the circulation path, extracting the problematic component that caused increased device complexity and cost. Instead, it uses the existing pump and control unit to perform circulation detection by comparing liquid delivery amounts under different operating conditions, thereby maintaining detection reliability without adding complex sensing hardware.
Solution Approach 2:
The system uses its own existing components (pump and control unit) to perform the circulation detection function. By operating the pump at different outputs and measuring the corresponding liquid delivery amounts, the system self-diagnoses circulation status without requiring external sensors, thus reducing device complexity while maintaining reliability.
2Measurement precision
If a pressure sensor is installed in the circulation path to monitor ink circulation flow, then the measurement precision of circulation flow is improved, but the device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical pressure sensing system with a control-based measurement approach. Instead of using a pressure sensor to directly measure circulation flow, the system uses the control unit to operate the pump at different outputs and compares the liquid delivery amounts, thereby achieving circulation flow measurement precision through computational methods rather than mechanical sensing.
Solution Approach 2:
The patent introduces the liquid delivery amount as an intermediary measurement parameter. Rather than directly measuring circulation flow with a pressure sensor, the system measures the liquid delivery amount under different pump outputs and uses this intermediate data to infer circulation status, achieving measurement precision through indirect but reliable means.
3Reliability
If a pressure sensor is installed in the circulation path to monitor ink circulation flow, then the reliability of circulation detection is improved, but the device size increases
Solution Approach 1:
The patent extracts the pressure sensor from the circulation path, removing the component that contributed to increased device size. By using the existing pump and control unit for circulation detection, the system maintains reliability without adding bulky sensing hardware to the circulation path.
Solution Approach 2:
The pump and control unit are made multi-functional, serving both their primary function of liquid circulation and the additional function of circulation detection. This eliminates the need for separate detection hardware, thereby maintaining reliability while reducing device size.
Data Source
AI summary
Provided is a liquid ejection apparatus and a testing method capable of detecting whether ink circulation flow is normal, while achieving size reduction and cost reduction. To this end, an ejection operation is performed with an output for a first circulation pump being lowered from an output for regular printing by a printing apparatus, and it is determined based on the result of the ejection operation whether liquid is circulating normally.