Liquid Ejection Head Pressure Control via Segmentation
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Solution Overview
Problem
Existing liquid ejection apparatuses face challenges in maintaining stable ejection due to pressure fluctuations within the liquid ejection head, which can be caused by both external scanning movements and internal pump pulsation.
Innovation Solution
The liquid ejection head incorporates a circulation pump and two pressure adjustment units, one between the pump's outlet and the supply channel, and the other between the pump's inlet and the collection channel, to regulate pressures and absorb pulsations, thereby stabilizing the ejection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a pump is mounted inside a liquid ejection head to circulate liquid, then the liquid circulation path becomes short and only a single channel needs to be drawn out, but pressure fluctuations due to pump pulsation become large causing oscillating movement of liquid
Solution Approach 1:
The patent divides the pressure control function into two independent pressure control units located at different positions in the liquid circulation path. One unit controls the supply channel while the other controls the collection channel, allowing independent pressure regulation to compensate for pump pulsations and maintain stable liquid levels in pressure chambers.
Solution Approach 2:
The patent introduces pressure control units as intermediary components between the pump and the pressure chambers. These units act as mediators that buffer and regulate pressure fluctuations, preventing direct transmission of pump pulsations to the liquid ejection system while maintaining efficient circulation.
2Productivity
If two channels are drawn out for supply and collection to a main body-side pump, then liquid can be circulated, but the channels swing during scanning causing pressure fluctuations
Solution Approach 1:
The patent extracts the pump function from the main body and integrates it directly into the liquid ejection head. This eliminates the need for long external channels that swing during scanning, while the added pressure control units compensate for the introduced pump pulsations, achieving both circulation and stability.
Data Source
AI summary
A liquid ejection head includes: an ejection element configured to generate a pressure for ejecting the liquid; a supply channel through which the liquid is supplied to a pressure chamber; a collection channel connected to the supply channel through the pressure chamber and through which the liquid is collected from the pressure chamber; a circulation pump capable of supplying the liquid from the supply channel into the pressure chamber, and collecting the liquid in the pressure chamber through the collection channel and sending the liquid to the supply channel; a first pressure adjustment unit disposed between an outlet channel of the circulation pump and the supply channel and configured to adjust a pressure in the supply channel; and a second pressure adjustment unit disposed between an inlet channel of the circulation pump and the collection channel and configured to adjust a pressure in the collection channel.