Liquid Ejection Head Pump Control Without Pressure Sensors
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Solution Overview
Problem
Existing liquid ejection apparatuses face challenges in downsizing due to the inclusion of pressure sensors in the liquid circulation channel, which complicates the design and functionality.
Innovation Solution
A liquid ejection apparatus with a circulation pump that adjusts its output based on an evaluation of the ejection state, using an evaluation unit and setting unit to ensure proper ink circulation and ejection, allowing for downsizing while maintaining high-quality printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure sensors are installed in the liquid circulation channel to detect pressures and control pump operation, then the liquid can be stably circulated, but it becomes difficult to downsize the liquid ejection head
Solution Approach 1:
The patent removes the pressure sensor from the liquid circulation channel and replaces it with a vibration sensor that detects vibrations generated by the liquid flow. This extraction of the pressure sensor eliminates the space requirement for installing pressure sensors in the circulation channel, enabling downsizing of the liquid ejection head while maintaining reliable liquid circulation control through vibration-based detection
Solution Approach 2:
The patent substitutes the mechanical pressure sensing system with a vibration detection system. Instead of using pressure sensors to detect liquid pressure in the circulation channel, the invention uses vibration sensors to detect vibrations generated by liquid flow, thereby replacing a mechanical measurement approach with a dynamic vibration-based approach that requires less space
2Reliability
If the circulation pump output is increased to prevent ink evaporation and clogging, then liquid circulation reliability improves, but the risk of liquid leakage from ejection ports increases
Solution Approach 1:
The patent implements a feedback control system where vibration sensors detect vibrations generated by liquid flow in the circulation channel, and the control unit adjusts the circulation pump output based on these vibration signals. This feedback mechanism enables precise control of liquid circulation, maintaining sufficient flow to prevent ink evaporation and clogging while avoiding excessive pump output that would cause liquid leakage from ejection ports
Solution Approach 2:
The patent dynamically adjusts the circulation pump output parameter based on real-time vibration detection. By changing the pump output parameter in response to detected vibration levels, the system optimizes liquid circulation to prevent harmful effects (evaporation and clogging) while avoiding excessive circulation that would cause liquid leakage
Data Source
AI summary
Provided is a liquid ejection apparatus including: a liquid ejection head having an ejection port and an ejection element configured to eject a liquid from the ejection port; a circulation pump configured to circulate the liquid to be supplied to the ejection port; an evaluation unit configured to change an output of the circulation pump and evaluate an ejection state in which the liquid is ejected from the ejection port by the ejection element; and a setting unit configured to set the output of the circulation pump based on a result of the evaluation of the ejection state by the evaluation unit.