Liquid Circulation in Inkjet Nozzles Without Capping
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Solution Overview
Problem
In liquid discharge apparatuses, the viscosity increase near the nozzle due to evaporation leads to blockages, making it difficult to discharge liquid, especially when the nozzle is not capped, and existing solutions require nozzle capping to maintain discharge characteristics.
Innovation Solution
A liquid discharge apparatus with a circulation flow path and a recovery mechanism that continuously circulates liquid during printing, reducing viscosity increase and agglomeration, and maintains discharge characteristics even when the nozzle is not capped by driving the circulation pump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid is circulated in the nozzle by capping the nozzle surface, then discharge characteristics are maintained, but the system cannot operate when the discharge head stops in a region other than the standby position
Solution Approach 1:
The patent extracts the capping function from the liquid circulation system. Instead of requiring the cap to be in place for circulation, the circulation pump is driven independently to circulate liquid through the flow path without needing the nozzle surface to be capped, thereby separating the circulation function from the capping function
Solution Approach 2:
The circulation pump acts as an intermediary device that enables liquid circulation without requiring direct contact with the nozzle surface. By driving the pump to circulate liquid through the supply and collection flow paths, the system achieves circulation without the cap, allowing operation in non-standby positions
2Use of energy by moving object
If liquid circulation is stopped to save energy, then energy consumption is reduced, but viscosity increases and causes blockage
Solution Approach 1:
The patent implements periodic circulation by driving the circulation pump at specific intervals rather than continuously. The control unit determines circulation timing based on printing conditions, creating a periodic action that balances energy savings with preventing viscosity-related blockages
Solution Approach 2:
The system changes the operational parameters of the circulation pump based on printing conditions. The control unit adjusts whether the pump operates continuously or periodically depending on factors such as printing frequency and liquid type, optimizing the balance between energy consumption and discharge functionality
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
The apparatus effectively prevents discharge characteristic degradation by continuously circulating liquid, reducing viscosity and agglomeration, and allows for uninterrupted printing even when the nozzle is not capped, extending the time before recovery is needed.
Implementation Method 1
the viscosity of liquid increases in the vicinity of a nozzle formed at a discharge head as water in the liquid evaporates from the nozzle
Data Source
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AI summary
It is intended to excellently maintain a discharge characteristic of a discharge head (101). A liquid discharge apparatus (100) includes a discharge head (101) including a nozzle for discharging liquid, a circulation unit capable of circulating liquid through a circulation flow path including the discharge head (101), a cap unit capable of capping a nozzle surface of the discharge head (101) where the nozzle is formed, and a control unit (203) for controlling the discharge head (101), the circulation unit, and the cap unit. In a case where anomaly is detected and the cap unit cannot cap the nozzle surface, the control unit (203) causes the circulation unit to circulate liquid through the circulation flow path.