Inkjet Buffer Tank Bubble Purge via Dual Channel Switching
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Solution Overview
Problem
In fluid ejection devices with a buffer tank, bubbles entering the buffer tank from the cartridge can accumulate and cause ejection problems when they flow to the printhead, requiring extensive fluid discharge for purging, leading to significant ink wastage.
Innovation Solution
A fluid ejection device with a channel switching mechanism that allows fluid to flow through either a first channel to the printhead or a second channel for purging, using valves to redirect the flow path efficiently, minimizing ink consumption during bubble removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a large capacity buffer tank is used to enable cartridge replacement without stopping fluid ejection operation, then the ability to replace cartridges without interruption is improved, but bubbles accumulate in the buffer tank over time and cause ejection problems
Solution Approach 1:
The fluid path is segmented into multiple channels: a first channel for normal fluid ejection and a second channel for bubble discharge. This segmentation allows the system to separately handle fluid transport and bubble removal, preventing bubbles from reaching the ejection head while maintaining continuous operation capability.
Solution Approach 2:
A channel switching mechanism acts as an intermediary between the buffer tank and the fluid ejection system. It selectively directs fluid through different paths based on operational needs, enabling bubble purging without interrupting the overall fluid ejection operation.
2Reliability
If a cleaning operation is executed to discharge bubbles from the buffer tank, then bubble accumulation is prevented, but substantially all fluid in the buffer tank must be discharged, wasting a large amount of fluid
Solution Approach 1:
The second channel is specifically designed to extract and remove only bubbles from the buffer tank, separate from the main fluid path. This allows selective removal of harmful bubbles while preserving the majority of the fluid in the buffer tank for continued use.
Solution Approach 2:
The channel switching mechanism enables localized bubble removal from specific regions of the buffer tank through the second channel, rather than requiring complete fluid discharge. This localized approach maintains fluid in the buffer tank while eliminating bubbles from problematic areas.
Data Source
AI summary
Ink consumption accompanying purging bubbles from the buffer tank is suppressed. An inkjet printer has a buffer tank disposed to an ink path that supplies ink to a printhead. A first channel connects to the buffer tank at the bottom of the ink chamber, and a second channel connects to the top of the ink chamber. To print, the first valve and second valve are open, and ink is supplied from the first channel, into which bubbles do not easily flow. To purge bubbles, the first valve closes and the maintenance unit is driven in a cleaning operation, discharging bubbles with ink from the second channel. The second valve then closes, the maintenance unit is driven to create negative pressure downstream from the second valve, and the second valve then opens in a choke cleaning operation that discharges ink with entrained bubbles at once.