Ink Delivery System Bypass for Air Bubble Management
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Solution Overview
Problem
Inkjet printers face issues with air bubbles causing blockages and reduced efficacy of ink filters, leading to inconvenient and costly filter replacements, despite existing solutions like deaeration pumps that still experience excessive foaming and blockages during printhead depriming.
Innovation Solution
An ink delivery system with an ink recirculation pump, bypass line, and valves that coordinate the flow of ink around the filter to prevent air accumulation, ensuring ink is pumped through the filter only when air-free, thereby extending filter life and reducing service interventions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If air bubbles are allowed to circulate in the ink delivery system during printhead depriming, then the printhead can be replaced, but air bubbles accumulate in the ink filter causing blockages and reduced filter efficacy
Solution Approach 1:
The ink delivery system is segmented into multiple pathways: a primary pathway through the ink filter for normal operation, and a secondary bypass pathway for air bubble management. This segmentation allows air bubbles to be diverted away from the filter during depriming operations while maintaining filter integrity during normal printing.
Solution Approach 2:
A bypass line acts as an intermediary pathway between the ink delivery system components. During printhead depriming, air bubbles are routed through this intermediary bypass line rather than through the ink filter, preventing filter blockage while still allowing the depriming operation to proceed.
2Reliability
If air bubbles are removed from the ink delivery system using a deaeration pump, then air accumulation is reduced, but excessive foaming still occurs during printhead depriming
Solution Approach 1:
The harmful air bubbles are extracted from the main ink flow path and diverted into a separate bypass line. This extraction prevents air bubbles from reaching the ink filter during depriming operations, eliminating the root cause of excessive foaming while maintaining effective air bubble management.
Solution Approach 2:
The air bubbles, which are normally harmful and cause foaming, are converted into a manageable flow characteristic in the bypass line. By routing air bubbles through the bypass line with appropriate flow dynamics, the system transforms a harmful factor into a controlled flow pattern that prevents filter blockage without generating excessive foam.
3Reliability
If the ink filter is continuously operated without bypass, then filtration is maintained, but air bubbles block the filter pores causing catastrophic blockages and requiring filter replacement
Solution Approach 1:
The bypass line provides a preliminary alternative pathway that prevents air bubbles from reaching the ink filter before they can cause blockages. This preliminary diversion action protects the filter during depriming operations and extends filter lifetime while maintaining continuous filtration capability.
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
The system effectively manages air bubbles, prolongs the life of ink filters, and minimizes the need for frequent replacements, maintaining proper filtration and reducing service requirements while ensuring optimal print quality.
Implementation Method 1
an ink recirculation pump positioned in the ink return line
Implementation Method 2
an ink filter positioned in the ink return line
Data Source
AI summary
An ink delivery system for delivering ink to an inkjet printhead includes: an ink tank; the inkjet printhead having a printhead inlet port and a printhead outlet port; an ink supply line connected between the ink tank and the printhead inlet port; an ink return line connected between the ink tank and the printhead outlet port; an ink recirculation pump positioned in the ink return line; an ink filter positioned in the ink return line; a bypass line for bypassing ink around the ink filter; a bypass valves for controlling flow of ink either through the ink filter or through the bypass line; and a controller for coordinating the bypass valve and the pump. The controller is configured to pump ink from the printhead outlet port to the ink tank via the bypass line when the return line contains air.