Inkjet Printer Bubble Removal via Storing Portion
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Solution Overview
Problem
Inkjet printers face ejection failures and reduced droplet volume due to bubbles trapped upstream of the filter in the ink-flow passage, which cannot be effectively removed using conventional suction methods, especially in large-scale recording heads with increased flow passage cross-sections.
Innovation Solution
The implementation of a bubble-storing portion in the ink-flow passage downstream of the filter, where a bubble is expanded by negative pressure and then released, creating a differential pressure to break the meniscus and forcibly move the bubble through the filter, combined with a bubble-injecting device to manage bubble volume and facilitate removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional suction methods are used to remove bubbles upstream of the filter, then the suction device can operate, but bubbles cannot be effectively removed especially in large-scale recording heads
Solution Approach 1:
A bubble-storing portion is introduced as an intermediary component between the filter and the suction device. This portion temporarily stores bubbles that pass through the filter, allowing them to be collected and removed by the suction device without interfering with normal ink flow. The bubble-storing portion acts as a mediator that decouples the bubble removal function from the ink ejection function.
Solution Approach 2:
The harmful bubbles are extracted from the ink flow path by introducing a bubble-storing portion that captures and isolates them. The bubbles are separated from the ink stream and stored in a dedicated compartment, preventing them from causing ejection failures while allowing the suction device to operate independently.
2Force
If high pressure is applied to generate sufficient suction force, then bubbles can be forced through the filter, but meniscus break occurs and ink flows backward through the filter
Solution Approach 1:
The bubble-storing portion is positioned to intercept bubbles before they can cause meniscus break in the filter. By pre-storing bubbles in this dedicated space, the system performs the bubble removal action before the harmful effect (meniscus break) can occur, allowing gentle suction without requiring excessive force that would disrupt the filter's ink flow.
Solution Approach 2:
The bubble-storing portion serves as an intermediary space that allows bubble accumulation without directly confronting the filter. This mediator space enables bubble storage at lower pressures, avoiding the need to apply high suction forces that would cause meniscus break and backward flow through the filter.
3Productivity
If the ink-flow passage cross-section is increased for large-scale recording heads, then flow resistance is reduced, but bubbles are more likely to be retained upstream of the filter
Solution Approach 1:
The ink-flow passage is segmented into distinct functional zones: the main flow path for high-speed ink delivery, and a separate bubble-storing portion for bubble management. This segmentation allows the main passage to maintain large cross-section for productivity while the bubble portion handles bubble removal, preventing bubbles from accumulating in the high-speed flow path.
Solution Approach 2:
The bubble-storing portion acts as an intermediary space that decouples the high-speed ink flow from bubble accumulation. Bubbles are captured in this separate compartment rather than being retained in the main ink-flow passage, allowing large cross-section design for productivity without compromising bubble removal reliability.
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 solution securely removes bubbles from the upstream of the filter, preventing ejection failures and ensuring consistent inkjet performance, allowing for the formation of excellent images by effectively managing bubble presence and flow.
Implementation Method 1
a bubble is expanded by negative pressure and then released, creating a differential pressure to break the meniscus
Implementation Method 2
creating a differential pressure to break the meniscus and forcibly move the bubble through the filter
Implementation Method 3
a vacuum pump for sucking the ink from the ejection opening through the vacuum cap
Data Source
AI summary
Disclosed is an inkjet printer including: a recording head having nozzles for ejecting ink; an ink tank for reserving the ink; an ink-flow passage for supplying the ink from the ink tank to the recording head; a valve for opening or closing the ink-flow passage; a filter disposed in the ink-flow passage between the valve and the recording head; a vacuum cap to be coupled to the recording head so as to cover an ejection opening of the nozzle when sucking an ink from the ejection opening; and a vacuum pump for sucking the ink from the ejection opening through the vacuum cap, wherein the printer includes a bubble-storing portion provided at least at a part of the ink-flow passage between the filter and the recording head, for storing a predetermined volume of bubble.