Selective Nozzle Purge with Localized Heating
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Solution Overview
Problem
Existing liquid droplet jetting apparatuses face issues with efficiently clearing jetting failures in defective nozzles while minimizing the unnecessary discharge of liquid from normal nozzles during the purge operation, leading to excessive ink wastage.
Innovation Solution
A liquid droplet jetting apparatus equipped with a judgment mechanism to identify defective nozzles, a heating mechanism to reduce the viscosity of ink in the defective nozzle channels, and a controller to coordinate the purge operation, allowing for targeted heating and suction to facilitate easy discharge from defective nozzles without affecting normal ones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strong suction force is exerted from the pump to discharge bubbles and viscous liquid from defective nozzles, then jetting failure is cleared, but liquid is discharged from all nozzles including normal ones causing excessive ink wastage
Solution Approach 1:
The patent divides the liquid channels into two groups: purge target channels connected to the pump for defective nozzles, and non-purge channels for normal nozzles. This segmentation allows selective suction force application only to channels containing bubbles and viscous liquid, while normal channels are excluded from the purge operation, thereby preventing unnecessary ink discharge from functional nozzles.
Solution Approach 2:
The patent applies different treatment to different liquid channels based on their contents. Purge target channels receive strong suction force to remove bubbles and viscous liquid, while non-purge channels maintain normal pressure conditions. This local differentiation ensures that suction force is exerted only where needed (in defective channels) rather than uniformly across all channels, reducing overall liquid wastage.
2Reliability
If purge operation is performed on all nozzles to ensure complete clearance of jetting failures, then reliability is improved, but the amount of liquid to be discarded increases due to discharge from normal nozzles
Solution Approach 1:
The patent segments the nozzle system into purge target nozzles (defective) and normal nozzles (non-purge). By connecting the pump only to the purge target channels, the system performs comprehensive purging of defective nozzles while completely excluding normal nozzles from the purge operation, thus maintaining reliability without the penalty of discarding liquid from functional nozzles.
Solution Approach 2:
Instead of applying purge operation to all nozzles (excessive action), the patent applies partial action only to the subset of nozzles that actually require purging (defective nozzles with bubbles and viscous liquid). This partial approach ensures adequate clearance of jetting failures while minimizing unnecessary liquid discharge from normal nozzles.
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 approach effectively clears jetting failures in defective nozzles while reducing the overall amount of ink discharged from all nozzles, minimizing wastage and maintaining normal nozzle functionality.
Implementation Method 1
a heating mechanism which heats the liquid in the plurality of individual channels
Implementation Method 2
flows directed toward purge target nozzles, among the plurality of nozzles, communicating with the purge target individual channels respectively are caused in the liquid in the purge target individual channels to discharge the liquid from the purge target nozzles
Data Source
AI summary
There is provided a liquid droplet jetting apparatus, including: a liquid droplet jetting head in which a plurality of nozzles and a plurality of individual channels are formed; a purge mechanism; a judgment mechanism which judges whether or not a defective nozzle in which a jetting failure occurs is included in purge target nozzles; a heating mechanism which heats a liquid in the plurality of individual channels; and a controller which controls the purge mechanism and the heating mechanism. In a case that the judgment mechanism judges that the defective nozzle is included in the purge target nozzles, the controller controls the heating mechanism and the purge mechanism to heat the liquid in a part of the plurality of individual channels, which include an individual channel communicating with the defective nozzle, and to execute the purge operation for the purge target nozzles.