Liquid Discharge Head Throttle Resistance for Air Removal
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Solution Overview
Problem
The existing liquid discharge heads face challenges in effectively discharging air accumulated near nozzles to the recovery channel, leading to impaired discharge characteristics due to slow ink flow rates.
Innovation Solution
A liquid discharge head design with upstream-side and downstream-side throttle channels, where the channel resistance of the upstream-side throttle channel is smaller than that of the downstream-side throttle channel, facilitating faster ink flow and effective air removal by adjusting the drive timing of the actuators to synchronize pressure wave propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the liquid flows from the supply channel to the recovery channel via the individual channels, then the air accumulated in the vicinity of the nozzles can be discharged to the recovery channel, but if the flow rate of liquid in the vicinity of the nozzles is slow, the air cannot be discharged effectively
Solution Approach 1:
The patent changes the resistance parameters of the throttle channels to optimize liquid flow rate. By making the upstream-side throttle channel resistance smaller than the downstream-side throttle channel resistance, the liquid flow rate in the vicinity of the nozzles is increased, enabling effective air discharge while maintaining proper liquid circulation.
2Speed
If the channel resistance of the upstream-side throttle channel is made smaller than that of the downstream-side throttle channel, then the liquid flow rate increases and air can be discharged effectively, but the pressure distribution and actuator synchronization become more complex to control
Solution Approach 1:
The patent applies different resistance characteristics to different parts of the throttle channel system. The upstream-side throttle channel has smaller resistance while the downstream-side throttle channel has larger resistance, creating localized quality differences that optimize both flow rate and pressure distribution for effective air discharge.
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
This design enhances the discharge of air from the nozzle area to the recovery channel, improving discharge characteristics and reducing heat generation in the driver IC by optimizing the flow rate and pressure distribution.
Implementation Method 1
first piezoelectric elements (upstream-side actuators) that apply pressure to the ink in the first pressure chambers and second piezoelectric elements (downstream-side actuators) that apply pressure to the ink in the second pressure chambers
Data Source
AI summary
A liquid discharge head includes: individual channels; a supply channel connected to inlets of the individual channels and through which liquid is supplied to the individual channels; and a recovery channel connected to outlets of the induvial channels and through which the liquid is recovered from the individual channels. Each of the induvial channels includes: a nozzle; an upstream-side pressure chamber disposed between the nozzle and the supply channel; a downstream-side pressure chamber disposed between the nozzle and the recovery channel; an upstream-side throttle channel connecting the supply channel and the upstream-side pressure chamber; and a downstream-side throttle channel connecting the recovery channel and the downstream-side pressure chamber. A channel resistance of the upstream-side throttle channel is smaller than a channel resistance of the downstream-side throttle channel.