Ink Storage Chamber Design for Bubble-Free Liquid Level Detection
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Solution Overview
Problem
Existing inkjet printing apparatuses face errors in detecting the liquid surface height of ink due to bubbles, which can occur when the ink level lowers, affecting both electrode and optical detection methods, especially in sub-tanks without an air vent.
Innovation Solution
A printing apparatus design featuring a storage chamber with a first and second space, where the distance between the side walls is greater in the second space, allowing for accurate ink surface detection by positioning the detecting unit in the second space, thereby minimizing bubble interference and ensuring reliable detection regardless of the presence or absence of an air vent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the liquid surface height is detected using electrode pins or optical sensors in a sub-tank, then the remaining ink amount can be determined, but bubbles may interfere with detection causing incorrect readings
Solution Approach 1:
The sub-tank is divided into two chambers by a partition wall. The first chamber (bubble collection chamber) is separated from the second chamber (detection chamber), allowing bubbles to be trapped in the first chamber while keeping the detection area in the second chamber free of bubbles. This segmentation resolves the contradiction by spatially separating the bubble accumulation zone from the detection zone.
Solution Approach 2:
The harmful bubbles are extracted and isolated from the detection area by directing them into a separate first chamber through the partition wall structure. The detection sensor is positioned only in the second chamber, effectively removing bubble interference from the detection process while maintaining overall system functionality.
2Object-affected harmful factors
If a partition is provided in a sub-tank without an air vent to trap bubbles, then bubble interference may be reduced, but bubbles still enter the detection chamber when liquid surfaces lower
Solution Approach 1:
The partition wall is positioned at a specific height to create asymmetric chamber volumes. The first chamber has a larger volume to accommodate bubble accumulation, while the second chamber maintains a controlled environment for detection. This local quality differentiation ensures that even when liquid levels drop, bubbles preferentially occupy the first chamber and do not contaminate the detection area in the second chamber.
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 design effectively suppresses ink liquid surface detection errors by preventing bubbles from entering the detection area, ensuring accurate ink level monitoring and maintaining printing operations even when the ink level is low.
Implementation Method 1
The optical method is a method of detecting the liquid surface height of ink based on the reflection state of a light beam by a photosensor and a prism.
Implementation Method 2
The electrode method is a method of detecting the liquid surface height of ink based on the electrically connected state between two electrode pins provided in a tank.
Data Source
AI summary
A printing apparatus according to the present invention includes a storage chamber, a first communicating portion through which an ink tank communicates with the storage chamber, a second communicating portion through which a printhead is communicates with the storage chamber, and side walls arranged facing each other so as to form a channel in which ink flows from a side of the first communicating portion to a side of the second communicating portion in the storage chamber. The storage chamber includes a first space, and a second space located closer to the side of the second communicating portion than the first space, in which a distance between the side walls is set larger than in the first space. The apparatus includes a detecting unit arranged in the second space and detecting a liquid surface of ink.