Inkjet Nozzle Purge Control via Selective Suction
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Solution Overview
Problem
Conventional ink-jet printers face challenges in performing effective purges due to variations in nozzle discharge during complete and partial purges, leading to insufficient or excessive ink discharge, which can result in incomplete removal of thickened ink or air bubbles from nozzles.
Innovation Solution
A liquid droplet jetting apparatus with a suction mechanism that controls the difference in discharge amount and flow speed between complete and partial purges by selectively blocking communication between ink supply sections and the atmosphere, ensuring consistent purge performance across all nozzles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complete purge is performed for all nozzles, then all nozzles are cleaned, but excessive ink is discharged from nozzles that do not require purging
Solution Approach 1:
The purge operation is segmented into complete purge mode (all nozzles) and partial purge mode (selected nozzles only). The suction pump selectively connects to specific nozzle groups based on detected defects, allowing targeted purging without unnecessarily discharging ink from all nozzles when only some require maintenance.
Solution Approach 2:
Different purge strategies are applied to different nozzle groups based on their individual conditions. Nozzles with detected defects (thickened ink or air bubbles) receive purging treatment, while nozzles in good condition are excluded from the purge operation, optimizing both effectiveness and ink consumption.
2Loss of substance
If a partial purge is performed for specific nozzles, then ink discharge is controlled, but insufficient ink may be discharged from nozzles requiring purging
Solution Approach 1:
The system incorporates a detection mechanism that identifies nozzle conditions (thickened ink, air bubbles, or normal state) before initiating purging. Based on this feedback, the control unit determines which nozzles require purging and configures the suction pump accordingly, ensuring adequate ink discharge for effective purging while avoiding excessive discharge from healthy nozzles.
3Productivity
If the suction pump operates with all nozzles connected, then all nozzles are purged simultaneously, but the flow speed and discharge amount vary between nozzles
Solution Approach 1:
The nozzle system is divided into multiple independently controllable groups connected to the suction pump through separate channels. This segmentation allows the pump to maintain consistent flow speed and discharge amount for each group by controlling the opening degree of individual channel valves, ensuring uniform purging performance across all nozzles while maintaining high productivity.
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 ensures a sufficient purge in all nozzles during complete purges and prevents excessive ink discharge during partial purges, maintaining optimal jetting performance and preventing defects.
Implementation Method 1
The ink is discharged by sucking from the nozzles (suction purge) by generating a negative pressure inside the suction caps by the suction pump
Data Source
AI summary
A printer controls a suction pump such that a difference in a discharge amount of an ink and a flow speed of the ink discharged from each nozzle is small between a complete purge in which all ink supply portions connected to a second head communicate with an atmosphere, and a suction purge is performed simultaneously for the nozzles of all types of the second head, and a partial purge in which a communication of a part of the ink supply portions with the atmosphere is blocked by a dummy cartridge, and the suction purge is performed only for the nozzles corresponding to the ink supply portions of which the communication with the atmosphere is not blocked.