Ink Tank Segmentation for Bubble-Free Pressure Regulation
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Solution Overview
Problem
Inkjet printers face challenges in supplying degassed ink to printheads without regassing, as existing ink delivery systems expose ink to air, leading to air bubbles and performance issues during long print runs.
Innovation Solution
An ink tank system with a first ink chamber for degassed ink and a second chamber connected via a diffusion tube, allowing gravity-controlled pressure regulation without mixing aerated ink, where the diffusion tube is designed to minimize air bubble ingress and maintain ink pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If ink is exposed to air for pressure regulation in a gravity-feed system, then ink pressure is controlled, but ink becomes regassed and air bubbles form
Solution Approach 1:
The ink tank is divided into two separate chambers: a first chamber that remains sealed to maintain degassed ink, and a second chamber that is open to atmosphere for pressure regulation. This segmentation allows each chamber to fulfill its specific function without compromising the other.
Solution Approach 2:
A diffusion tube acts as an intermediary element connecting the two chambers. It allows slow diffusion of gas molecules while preventing rapid mixing, enabling pressure equalization without immediate regassing of the degassed ink in the first chamber.
2Reliability
If a diffusion tube is used to connect chambers, then gas diffusion is minimized, but pressure equalization is slow
Solution Approach 1:
The system exploits the parameter of diffusion timescale by designing the diffusion tube with specific dimensions and properties that create a diffusion barrier. This allows the system to operate on timescales where diffusion is slow enough to protect ink quality but sufficient for pressure equalization during normal operation.
3Quantity of substance
If the first ink chamber has larger volume, then more degassed ink is stored, but diffusion to the second chamber increases
Solution Approach 1:
The tank is segmented into two chambers with the first chamber optimized for storing degassed ink and the second chamber optimized for pressure regulation. The diffusion tube creates a controlled connection that limits gas exchange while allowing pressure equalization.
Solution Approach 2:
Different regions of the system have different functional qualities: the first chamber maintains a sealed, diffusion-limited environment for ink storage, while the second chamber provides an open atmosphere interface for pressure control. Each chamber's volume and characteristics are optimized for its specific function.
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 regulates ink pressure using gravity without regassing the ink, ensuring stable performance by isolating the first ink chamber from air exposure and maintaining ink quality.
Implementation Method 1
a diffusion tube interconnecting the first and second ink chambers
Implementation Method 2
A difference in height between the printhead and the head of ink in the pressure-regulating tank controls the backpressure in the printhead
Data Source
AI summary
An ink tank for an ink delivery system in a printer includes: a lower portion having an ink inlet port and an ink outlet port; and an upper portion having a roof defining a tortuous vent pathway open to atmosphere via a gas port. The lower portion has a smaller volume than the upper portion.