Liquid Ejection Head Flow Path Design for Ink Quality Control

The patent applies local quality by creating distinct flow regions: a first flow region where liquid flows from the supply passage to the ejection opening, and a second flow region where liquid flows from the ejection opening to the outflow passage. By locally controlling the flow characteristics in these different regions, the patent maintains liquid quality uniformity near the ejection opening while still allowing circulation to prevent clogging.

The patent segments the passage into multiple functional sections: a supply passage for liquid inflow, a first passage section for circulation, an ejection opening portion for communication, and a second passage section for outflow. This segmentation allows each section to be optimized for its specific function, preventing clogging while maintaining liquid quality consistency.

The patent implements continuous liquid circulation through the passage, ensuring that liquid is continuously supplied to prevent clogging and maintain productivity. The flow path is designed to continuously move liquid from the supply passage through the ejection opening portion to the outflow passage, maintaining steady-state conditions that preserve ink ejection quality.

The patent introduces an intermediary flow path design where the passage is configured with specific geometric parameters (width W, height H, length L) that act as a mediator between the supply passage and outflow passage. This intermediary structure controls the flow characteristics to prevent direct mixing that would cause quality changes, while still enabling continuous circulation.