Suction Cap Segmentation for Nozzle Pressure Control
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Solution Overview
Problem
Existing liquid discharge apparatus maintenance methods often cause pressure changes that can damage the nozzle surface, leading to discharge failures, as the suction cap's pressure change affects the meniscus of the nozzle hole during separation.
Innovation Solution
A maintenance apparatus with a cap that contacts the liquid discharge head, a suction unit, an opening and closing valve, and a micro-opening port that maintains atmospheric communication with the first path, preventing ink from flowing back into the suction cap and minimizing pressure changes during suction and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a suction cap is brought into contact with a nozzle surface and suction is performed to restore dischargeability, then liquid can be absorbed from the liquid discharge head, but the nozzle surface is affected by pressure change in the suction cap when separated, causing discharge failure
Solution Approach 1:
The suction cap is divided into two separate chambers: a first chamber that contacts the nozzle surface for suction, and a second chamber that communicates with the atmosphere. This segmentation allows the first chamber to maintain negative pressure for effective suction while the second chamber provides atmospheric pressure reference, preventing pressure-induced meniscus damage during separation.
Solution Approach 2:
A partition wall with an opening (or a small hole) acts as an intermediary between the first and second chambers. This intermediary structure allows controlled pressure equalization or atmospheric communication that prevents sudden pressure changes from affecting the nozzle surface when the suction cap is separated, thereby protecting the meniscus while maintaining suction effectiveness.
2Power
If the suction cap is sealed during suction to maintain negative pressure, then suction effectiveness is improved, but ink may flow back into the suction cap after suction stops
Solution Approach 1:
The suction cap is segmented into a first chamber for suction operation and a second chamber for atmospheric communication. During suction, the first chamber remains sealed to maintain negative pressure and suction power, while the second chamber provides a pressure reference. After suction stops, the second chamber allows pressure equalization that prevents ink from flowing back into the suction cap, thereby resolving the contradiction between maintaining suction power and preventing ink reflux.
Solution Approach 2:
Different chambers of the suction cap have different pressure characteristics: the first chamber maintains negative pressure during suction for effective liquid absorption, while the second chamber communicates with or equalizes to atmospheric pressure. This local quality differentiation allows the system to achieve both strong suction power and reliable ink flow back prevention through spatially differentiated pressure zones.
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 solution effectively prevents ink from flowing into the first path and reduces pressure changes, thereby minimizing the risk of discharge failures and maintaining the nozzle's integrity during maintenance operations.
Implementation Method 1
perform suction by means of a pump or the like to establish a negative pressure in the suction cap
Implementation Method 2
causing a path coupled to a suction cap to communicate with the atmosphere and then separating the suction cap from a nozzle surface
Data Source
AI summary
A maintenance apparatus includes: a cap contactable with a nozzle surface of a liquid discharge head; a suction unit coupled to the cap to suck a liquid in the cap; a valve coupled to the cap with a first path, the valve to cause the first path to be opened and closed to an atmosphere; a second path branched from the first path; and an opening port coupled to the second path and communicating with the atmosphere.