Liquid Supply Unit with Pressure Chamber for Ink Ejection
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Solution Overview
Problem
Conventional liquid ejection devices face challenges in efficiently supplying ink to the ejection head while preventing air bubbles and ensuring consistent negative pressure, leading to issues like ink dripping and clogging.
Innovation Solution
A liquid ejection device with a liquid supply unit featuring a pressure chamber, exhaust valve, pump mechanism, and controller that executes specific control modes for ink circulation and pressure management, including ejection control, first and second circulation controls, and pressurized purge modes to maintain negative pressure and prevent air bubbles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ink is supplied to the liquid ejection head via a pressure chamber for generating negative pressure, then unlimited dripping of ink is suppressed, but air bubbles are generated in the pressure chamber during initial usage and maintenance
Solution Approach 1:
The patent extracts the harmful air bubbles from the pressure chamber by providing a dedicated exhaust passage that communicates with the atmosphere. The exhaust valve selectively opens this passage to vent air bubbles during initial filling and maintenance operations, while keeping the passage closed during normal operation to maintain negative pressure and prevent ink dripping.
Solution Approach 2:
The patent applies preliminary action by providing an exhaust mechanism that is activated during initial usage and maintenance to remove air bubbles before they can cause problems. The controller automatically opens the exhaust valve during these phases to vent air, and then closes it before normal ejection operations begin.
2Reliability
If a liquid supply unit with pressure chamber and exhaust valve is added to control ink supply, then ink dripping is prevented, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into the liquid supply unit: the pressure chamber serves both as a storage container and as a negative pressure generation chamber; the exhaust valve is integrated into the supply passage structure; and the pump mechanism performs both ink circulation and air bubble removal functions. This consolidation reduces overall system complexity despite adding control capabilities.
Solution Approach 2:
The pressure chamber is designed to serve multiple purposes: storing ink, generating negative pressure to prevent dripping, and providing a controlled environment for air bubble venting. The exhaust valve similarly serves dual functions of venting air during maintenance and maintaining sealed conditions during operation.
3Productivity
If pump mechanism is used to feed liquid to the supply passage, then consistent liquid flow is achieved, but energy consumption increases
Solution Approach 1:
The patent employs periodic action by operating the pump mechanism only when necessary - during initial filling, maintenance operations requiring air bubble removal, and when ink level needs replenishment. During normal ejection operations, the pump remains inactive and ink is supplied passively through the pressure chamber's negative pressure, significantly reducing energy consumption while maintaining flow consistency.
Solution Approach 2:
The system uses self-service by relying on the pressure chamber's negative pressure to automatically regulate ink flow to the ejection head without continuous pump operation. The pump only intervenes periodically to replenish ink levels and remove air bubbles, allowing the system to maintain consistent supply through passive pressure regulation during normal operation.
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 device effectively supplies ink to the ejection head, prevents air bubbles, and maintains consistent negative pressure, reducing ink dripping and clogging, thereby enhancing printing performance and reliability.
Implementation Method 1
The pump mechanism is capable of feeding the liquid to the second supply passage
Implementation Method 2
an exhaust valve configured to release or close the pressure chamber to or from outside air
Implementation Method 3
a pressure chamber for setting a discharge hole of a liquid ejection head to a negative pressure
Data Source
AI summary
A liquid ejection device includes a liquid supply unit configured to supply liquid to a liquid ejection head, a first supply passage, a second supply passage, a return pipe and a short-circuit pipe serving as a liquid flow passage, and a pump mechanism. A controller executes an ejection control for supplying the liquid from a pressure chamber to the liquid ejection head by opening first and second valve bodies and closing third and fourth valve bodies, a first circulation control for circulating the liquid through the liquid ejection head by closing the first and fourth valve bodies, opening the second and third valve bodies and operating the pump mechanism, and a second circulation control for circulating the liquid through the short-circuit pipe by closing the second valve body while opening the first, third and fourth valve bodies and operating the pump mechanism with an air vent mechanism released.