Inkjet Recirculation Channels for Bubble and Pigment Control
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Solution Overview
Problem
Inkjet printheads face issues with air bubble accumulation, pigment settling, and ink vehicle separation, leading to poor print quality and ink wastage due to the exposure of ink to ambient air and gravitational effects, which impede ink flow and cause blockages in the printhead.
Innovation Solution
A fluid ejection device with a recirculation system that includes asymmetrical short loop recirculation channels and drop generators, which helps in circulating the printing fluid, reducing air bubbles, and preventing pigment settling by mixing and agitating the ink, thereby maintaining nozzle health and ink efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ink is exposed to ambient air in the ink reservoir, then the ink can be supplied to the printhead, but air bubbles accumulate and block ink flow
Solution Approach 1:
The patent extracts and removes air bubbles from the ink reservoir using a bubble removal device that selectively removes gas bubbles while retaining ink particles, preventing bubble accumulation that would block ink flow to the printhead
Solution Approach 2:
The patent introduces a magnetic field as an intermediary mechanism to manipulate and remove air bubbles from the ink reservoir, using magnetic particles in the ink to create flow patterns that separate and remove bubbles without blocking ink supply
2Quantity of substance
If local evaporation of volatile ink components occurs, then ink can be stored, but pigment-ink vehicle separation and viscous plug formation prevent immediate printing
Solution Approach 1:
The patent maintains continuous magnetic field application or periodic pulsing to the ink reservoir to continuously mix and agitate the ink, preventing pigment-ink vehicle separation and viscous plug formation that would occur during storage, enabling immediate printing without ink spitting
Solution Approach 2:
The patent performs preliminary mixing and agitation of the ink during storage periods through magnetic field application, preparing the ink in advance to prevent separation and viscosity changes before printing is required, eliminating the need for ink spitting
3Productivity
If air bubbles are released from the firing chamber, then ink can be expelled, but bubbles migrate and block ink flow in the printhead
Solution Approach 1:
The patent extracts and removes air bubbles from the ink reservoir before they can enter the printhead, using a bubble removal device that selectively removes gas bubbles while retaining ink, preventing bubble migration and blockages in the ink flow path
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 recirculation system enhances inkjet pen performance by reducing pigment-ink vehicle separation, managing air bubbles, and improving image quality even after prolonged idling, resulting in high-resolution and efficient ink usage.
Implementation Method 1
A fluid ejection device with a recirculation system that includes asymmetrical short loop recirculation channels and drop generators, which helps in circulating the printing fluid
Implementation Method 2
preventing pigment settling by mixing and agitating the ink, thereby maintaining nozzle health and ink efficiency
Implementation Method 3
managing air bubbles, and improving image quality even after prolonged idling
Data Source
AI summary
A fluid ejection device may include a first channel having a first end and a second end, a first drop ejector along the first channel, a second channel having a first end and a second end, a second drop ejector along the second channel, a third channel extending between and connecting the first end of the first channel and the first end of the second channel, a fourth channel extending between and connecting the second end of the firs channel and the second end of the second channel and a fifth channel extending between and connecting the third channel and the fourth channel.