Ink Circulation Path Confirmation Using Downstream Tank Level Detection
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Solution Overview
Problem
Existing inkjet image forming apparatuses face challenges in confirming whether ink circulation is appropriately performed, particularly in detecting flow stoppages within the circulation path, which can lead to issues like increased temperature, bubble formation, and ink viscosity increases, affecting the recording head's performance.
Innovation Solution
A method involving a configuration with upstream and downstream tanks, ink paths, and sensors to detect ink displacement, including a first ink supply process, a second ink supply process, an ink supply stop process, time measurement, and comparison to ensure the ink circulation path is functioning correctly, with the ability to fill ink efficiently and prevent temperature increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple flow amount sensors are dispersively arranged on the circulation path to detect flow stoppages, then the detection capability is improved, but the device complexity and cost increase
Solution Approach 1:
The patent extracts the flow detection function from multiple distributed sensors and concentrates it into a single sensor placed in the downstream tank. This single sensor detects ink level changes that result from circulation flow, thereby detecting flow stoppages without requiring multiple sensors throughout the circulation path. This resolves the contradiction by maintaining detection capability while significantly reducing device complexity.
Solution Approach 2:
The patent introduces the downstream tank as an intermediary element that translates flow information into detectable signals. Instead of directly measuring flow at multiple points, the system uses the downstream tank's ink level as an intermediary indicator of circulation status. The single sensor monitors this intermediary parameter to infer flow conditions throughout the entire circulation path.
2Device complexity
If a single sensor is used to detect ink circulation, then the device complexity is reduced, but the measurement precision and reliability decrease
Solution Approach 1:
The patent creates a virtual representation of the circulation system's state through ink level measurements in the downstream tank. By monitoring how ink level changes over time in response to circulation pumping, the single sensor can infer circulation status, flow rate, and even detect blockages. This copying approach allows one sensor to capture system-wide circulation information that would otherwise require multiple direct flow sensors.
Solution Approach 2:
The system performs preliminary ink supply operations (first ink supply process and second ink supply process) to establish known reference states before using the sensor for circulation detection. By pre-filling the system and establishing baseline ink levels, the single sensor can more accurately detect deviations caused by circulation flow patterns, improving measurement precision through preparatory conditioning.
3Device complexity
If ink circulation is not properly monitored, then the device complexity is reduced, but harmful effects such as temperature increase, bubble formation, and viscosity increase occur
Solution Approach 1:
The patent implements a feedback mechanism where the single sensor continuously monitors ink level changes in the downstream tank, and this information feeds back to the control unit. The control unit adjusts the circulation pump operation based on detected circulation status, ensuring ink continues to flow through the recording head. This feedback loop prevents temperature increase, bubble formation, and viscosity increase by maintaining proper circulation without requiring complex monitoring systems.
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
This method allows for low-cost confirmation of ink circulation, preventing temperature rises, bubble removal, and maintaining ink viscosity within optimal ranges, ensuring the recording head operates effectively by detecting and addressing flow issues promptly.
Implementation Method 1
a sensor which detects a displacement amount of a parameter varying in response to an amount of ink in the downstream side tank
Implementation Method 2
Circulating the ink in such a manner prevents the recording head in drive from increasing its temperature by utilizing a radiation effect caused by moving ink
Implementation Method 3
circulating again the ink to the upstream side tank in order of the upstream side tank, the first ink path, the recording head, the second ink path, the downstream side tank, and the third ink path
Data Source
AI summary
An image forming apparatus which ejects ink to form an image on a recording medium flows the ink from an upstream side tank to a downstream side tank on an ink circulation path, includes a sensor for detecting a parameter corresponding to variations in amount of the ink in the downstream side tank, and confirms ink circulation in accordance with an amount of ink which returns through circulation from an appropriate amount of ink and a measured time.