Inkjet Printing Head Buffer Member Backflow Control
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Solution Overview
Problem
In inkjet printing apparatuses using tube pumps, backflow of fluid from the pump to the cap can generate air bubbles, mix inks, and disrupt ink ejection, leading to deteriorated image quality.
Innovation Solution
A buffer member is placed between the cap and the tube pump to store fluid flowing back from the pump, preventing backflow and maintaining ink quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the roller moves along the groove having long-hole geometry to release pressing force, then the tube pump can return to non-pressing position, but the tube may be pressed by the roller to generate backflow of fluid from pump to cap
Solution Approach 1:
A check valve is introduced as an intermediary component between the tube pump and the cap. This check valve allows fluid to flow from the cap to the pump during suction-recovery action, but prevents backflow from the pump to the cap when the roller releases pressing force, thus resolving the contradiction between roller movement and backflow prevention
Solution Approach 2:
The check valve is pre-configured to oppose the harmful backflow action before it occurs. When the roller moves along the groove to release pressing force, the check valve already prevents the reverse flow, eliminating the harmful effect before air bubbles can form or ink mixing can occur
2Quantity of substance
If backflow occurs from pump to cap, then fluid can flow back, but air bubbles are generated in ink and mixed colors are produced
Solution Approach 1:
The check valve serves as a mediator that permits necessary fluid flow from cap to pump for suction-recovery while blocking harmful backflow from pump to cap, thus maintaining ink ejection quality without compromising fluid circulation
Solution Approach 2:
The check valve converts the potential harmful backflow into a beneficial one-way flow system. The fluid flow that would otherwise cause air bubbles and mixed colors is redirected to flow only in the beneficial direction from cap to pump, turning a harmful phenomenon into a useful suction-recovery process
3Object-generated harmful factors
If air bubbles contact ejection opening, then meniscus is destroyed and gas flows in ejection opening, but ink ejection is prevented
Solution Approach 1:
The check valve performs preliminary anti-action by preventing air bubbles from reaching the ejection opening in the first place. By blocking backflow at the source, the check valve stops the chain of events that would lead to meniscus destruction and ink ejection failure, maintaining productivity without compromising the suction-recovery 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 buffer member effectively suppresses the influence of backflow, preventing air bubble generation and ensuring consistent ink ejection, thereby improving image quality by maintaining the integrity of the meniscus and preventing mixed colors.
Implementation Method 1
a tube pump connected with the cap and configured to be able to generate a negative pressure inside of the cap
Implementation Method 2
fluid flowing from the cap to the pump
Implementation Method 3
a buffer member provided between the cap and the tube pump and having a volume being capable of storing a fluid flowing from the tube pump to the cap
Data Source
AI summary
To provide an inkjet printing apparatus that can suppress influence by a backflow of the fluid flowing from the pump to the cap. An inkjet printing apparatus includes: an inkjet printing head including an ejection opening face formed with an ejection opening; a cap being capable of sealing the ejection opening face; a tube pump connected with the cap and configured to be able to generate a negative pressure inside of the cap; and a buffer member provided between the cap and the tube pump and having a volume being capable of storing a fluid flowing from the tube pump to the cap.