Liquid Discharge Device Ink Level Detection Sensor Failure
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Solution Overview
Problem
Inkjet printers face challenges in detecting residual ink levels and preventing air from entering the image recording unit when the liquid level sensor breaks down, leading to incorrect notifications and potential ink consumption issues.
Innovation Solution
A liquid discharge device with a controller that reads liquid amounts from both the cartridge and tank memories, calculates thresholds, and operates an alarm when a specific count value is reached, even if the liquid level sensor is malfunctioning, to notify users of ink exchange and prevent air from entering the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a liquid level sensor is used to detect residual ink levels, then the detection of ink levels is automated, but the system becomes vulnerable to sensor malfunction leading to incorrect notifications
Solution Approach 1:
The patent introduces an intermediary calculation system that uses discharge volume data as a mediator between the liquid level sensor and the final ink level determination. Instead of relying solely on the sensor's direct measurement, the system calculates remaining ink level by subtracting the cumulative discharge volume from the initial ink volume, providing a cross-verification mechanism that maintains reliability even when the sensor malfunctions.
Solution Approach 2:
The system implements feedback by continuously monitoring the discharge volume and using this information to update and verify the ink level status. The control unit compares the sensor-based liquid level information with the calculation-based remaining ink level, creating a feedback loop that can detect inconsistencies and prevent incorrect notifications due to sensor malfunction.
2Device complexity
If the system relies on liquid level sensor information alone, then the control logic is simple, but air may enter the image recording unit when the sensor breaks down
Solution Approach 1:
The system performs preliminary action by calculating the discharge volume and determining the remaining ink level in advance, before the actual printing operation completes. This allows the system to proactively identify when ink is running low and take preventive measures, such as notifying the user to replace the cartridge, thereby preventing air from entering the image recording unit even if the liquid level sensor later malfunctions.
Solution Approach 2:
The patent applies beforehand cushioning by creating a buffer verification mechanism through volume calculation. This dual-verification approach (sensor + calculation) acts as a cushion against sensor failure, ensuring that the system maintains accurate ink level awareness and prevents harmful air entry even when the primary sensing mechanism fails.
3Device complexity
If the system uses only sensor-based detection, then the notification system is simple, but incorrect notifications occur when the sensor malfunctions
Solution Approach 1:
The system applies self-service by having the control unit automatically perform volume calculations and compare them with sensor readings without requiring external intervention. The system self-verifies its ink level status by cross-checking multiple data sources (initial volume, discharge volume, and current sensor level), thereby maintaining accurate information and preventing incorrect notifications even when the sensor malfunctions.
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
Ensures accurate notification of ink levels and prevents air from entering the image recording unit, even when the liquid level sensor is faulty, thereby maintaining proper ink usage and system functionality.
Implementation Method 1
the ink moves due to a water head pressure so that the liquid level of the main tank and the liquid level of the sub tank are aligned with the same height by the difference between a water head in the internal space of the main tank and a water head in the internal space of the sub tank
Data Source
AI summary
A liquid discharge device includes a case receiving a cartridge having a first liquid chamber, a tank having a second liquid chamber, a head, a liquid level sensor, an interface, an alarm and a controller configured to: when the cartridge is installed in the case, read a liquid amount Vc stored in the first liquid chamber from a cartridge memory through the interface; read a liquid amount Vs stored in the second liquid chamber from a memory; calculate a threshold based on the liquid amount Vc read from the cartridge memory and the liquid amount Vs read from the memory; update a count value with a value equivalent to an amount of liquid instructed to be discharged by a discharge instruction; and operate the alarm when the updated count value reaches the threshold.