Inkjet Printer Air Bubble Discharge via Dynamic Pressure Control

The patent applies dynamic pressure control by switching between negative pressure generation and positive pressure application. During the air bubble discharge process, negative pressure is first applied to draw air bubbles toward the discharge direction, then positive pressure is applied to push the ink and remaining fine air bubbles through the filter and out of the ink passage. This dynamic pressure variation enables effective removal of fine air bubbles that static cleaning methods cannot eliminate.

The patent employs periodic action through repeated cycles of negative pressure generation followed by positive pressure application. This periodic pressure variation creates oscillating flow conditions that help detach and move fine air bubbles accumulated in the ink passage, particularly those trapped by the filter, enabling their progressive removal over multiple cycles.

The patent implements periodic action by alternating between negative pressure generation and positive pressure application in discrete cycles. The negative pressure generator operates intermittently rather than continuously, generating negative pressure for a predetermined time period, then stopping while positive pressure is applied. This periodic operation reduces energy consumption compared to continuous negative pressure generation while maintaining effective air bubble discharge through the cumulative effect of multiple cycles.

The patent ensures continuity of useful action by immediately following negative pressure generation with positive pressure application. This continuous sequence of pressure variations maintains the air bubble discharge process without interruption, ensuring that air bubbles are continuously moved toward and discharged from the ink passage while minimizing idle time when the negative pressure generator would consume energy without achieving additional discharge.