Liquid Ejection Head Humidification for Ink Drying Prevention

A cap mechanism is introduced as an intermediary component that physically covers the ejection openings when not in use. This cap creates a sealed environment that prevents direct exposure to dry air, thereby suppressing ink drying without requiring additional ink flushing operations. The cap acts as a mediator between the ejection openings and the external environment.

The patent creates a humidified enclosed space within the cap mechanism that forms an inert-like environment for the ink. By maintaining high humidity inside the cap when it covers the ejection openings, the evaporation of ink is significantly reduced, preventing drying without the need for flushing. This humidified environment functions similarly to an inert atmosphere by preventing unwanted chemical/physical changes to the ink.

The patent implements local quality by providing differentiated humid air supply to different regions of the head. The humidifying mechanism includes separate supply paths that deliver humid air preferentially to the end portions of the head when the cap is closed, rather than uniform supply across all regions. This localized approach addresses the specific drying tendency of end portions without unnecessarily complicating the entire system.

The humidifying mechanism is designed to dynamically adjust its operation based on the cap state. When the cap is closed, the system activates humid air supply to end portions; when the cap is open, the supply is reduced or stopped. This dynamic control optimizes humidity management while avoiding continuous operation that would increase energy consumption and system complexity.

The patent segments the humid air supply system into multiple independent channels, with separate supply openings positioned at different locations within the cap. This segmentation allows differentiated control of humidity distribution, enabling preferential supply to end portions that are more prone to drying. The segmented approach resolves the uneven humidity distribution problem while maintaining the protective enclosed environment.

The patent incorporates a control mechanism that monitors the cap state and adjusts humid air supply accordingly. When the cap is closed, the control system activates humid air supply to end portions; when the cap is open, the supply is reduced. This feedback-based control maintains optimal humidity distribution dynamically, preventing the uneven humidity problem that would occur with static supply configurations.