Inkjet Printhead Cleaning via Bidirectional Solvent Circulation
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Solution Overview
Problem
Industrial inkjet printing heads used in decoration often get blocked due to the chemical composition of inks, leading to inefficiencies in cleaning, especially with existing methods that rely on organic solvents and lack effectiveness against severe blockages.
Innovation Solution
A system that controls the temperature and pressure of a solvent, combined with air fluid pressure, and incorporates ultrasound to effectively clean the printing heads by circulating the solvent in both directions through the ink channels, utilizing a gasket for a fluid-tight seal and recirculating the solvent to minimize solvent consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic solvents are used to clean blocked inkjet printheads, then the cleaning process can dissolve ink residues, but the method is ineffective against serious and complicated blockages
Solution Approach 1:
The patent applies parameter changes by controlling the temperature of the solvent (heating to 50-80°C) and adjusting pressure differentials (using vacuum and positive pressure alternation) to enhance the cleaning effectiveness of the solvent against severe blockages while maintaining reasonable cleaning time
Solution Approach 2:
The patent incorporates ultrasonic vibration (20-40 kHz frequency) to agitate the solvent and create cavitation effects that mechanically dislodge stubborn ink blockages from the printhead nozzles, complementing the chemical cleaning action of the organic solvent
2Reliability
If high pressure is applied to force solvent through blocked channels, then cleaning effectiveness improves, but the risk of damaging piezoelectric devices increases
Solution Approach 1:
The patent applies preliminary anti-action by first creating a vacuum condition to draw the solvent through the blocked channels gently, then alternating with moderate positive pressure, rather than applying high pressure directly from the start, thereby preventing damage to piezoelectric devices while still achieving effective cleaning
Solution Approach 2:
The patent uses periodic alternation between vacuum suction and positive pressure application in cycles, allowing the solvent to penetrate blockages gradually without subjecting the piezoelectric devices to sustained high pressure that could cause damage
3Reliability
If large amounts of solvent are used to ensure thorough cleaning, then cleaning completeness improves, but solvent consumption and cost increase
Solution Approach 1:
The patent employs continuous circulation of the solvent through the printhead channels via the vacuum-positive pressure alternation system, ensuring that the same solvent volume is reused repeatedly to flush out blockages, thereby reducing the total amount of solvent needed compared to single-pass flooding methods
Solution Approach 2:
The system uses the vacuum and pressure differential to drive the solvent circulation automatically without requiring manual intervention or excessive solvent volume, allowing the solvent to clean itself through repeated circulation and filtration
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 system provides a high-efficiency cleaning method that effectively removes blockages from inkjet printing heads, reducing maintenance costs and improving the longevity of the printing heads by using controlled solvent circulation and ultrasound to break apart particles, ensuring a thorough cleaning while minimizing solvent usage.
Implementation Method 1
an ultrasound device, for breaking apart and breaking loose the particles making up the blockage inside the ink printing head
Implementation Method 2
a pressure control valve into which three ducts converge, which are linked to: the main drum, the pressure/vacuum switch and a gaseous fluid filter that connects to a compressed air intake
Implementation Method 3
a vacuum generator that is connected to the pressure/vacuum switch through a pipe
Data Source
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AI summary
A system for cleaning inkjet printing heads that is intended for cleaning these heads by means of a pressurized fluid, selected between a liquid solvent and a gaseous fluid, such as air. The pressurized fluid passes through various spaces inside the ink printing heads, through which ink normally flows when sprayed, in such a way that this path is taken in two circulation directions for much more effective cleaning. For cleaning, the ink printing head is placed inside a main tub, in such a way that the lower portion of the ink printing head is soaked in a liquid solvent contained within said first tub, further including, among other elements, a level control device that regulates the optimal height of the liquid solvent inside the main tub.