Ultrasonic Maintenance Cap for Printhead Cleaning
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Solution Overview
Problem
Existing printhead cleaning methods are inadequate for thoroughly removing unwanted matter from electrostatic printheads, particularly due to limitations in deep penetration and compatibility with ink, leading to inefficiencies and potential damage during the cleaning process.
Innovation Solution
A maintenance cap with an ultrasonic transducer generating acoustic waves between 20kHz and 100kHz is used to create cavitation bubbles, allowing for effective cleaning of the printhead's ejection region without the need for solvents or manual removal, by forming a sealed cleaning volume that immerses the ejection region in a compatible cleaning liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cleaning liquid is passed through the ejection region to remove debris, then some unwanted matter is removed, but the cleaning is inadequate for dried-on ink deposits and deep penetration is limited
Solution Approach 1:
The patent employs ultrasonic vibration (mechanical vibration at high frequency) to agitate the cleaning liquid and create cavitation bubbles that penetrate deep into the ejection region, effectively removing dried-on ink deposits and other unwanted matter that conventional liquid flow cannot reach or dissolve
Solution Approach 2:
The patent uses hydraulic principles by circulating cleaning liquid through the ejection region under pressure, combined with ultrasonic agitation, to ensure thorough penetration and contact with all surfaces including hard-to-reach areas of the printhead
2Reliability
If solvents or chemical baths are used to remove all unwanted matter, then complete cleaning is achieved, but manual removal is required and damage risk increases
Solution Approach 1:
The ultrasonic cleaning system is designed to be self-contained and automated, requiring no manual disassembly or handling of the printhead. The cleaning liquid circulates automatically through the ejection region, and ultrasonic transducers automatically generate the necessary vibration, eliminating the need for operator intervention and associated damage risks
Solution Approach 2:
The patent replaces manual mechanical cleaning operations (disassembly, hand-cleaning, reassembly) with an automated ultrasonic cleaning system that uses acoustic energy to perform the cleaning function, thereby eliminating the harmful effects of manual handling while achieving complete cleaning
3Reliability
If the printhead is removed for cleaning, then more thorough cleaning methods can be applied, but downtime increases and skill requirements increase
Solution Approach 1:
The patent incorporates the cleaning function directly into the printhead structure by providing cleaning liquid passages and ultrasonic transducer mounting within the printhead housing, allowing cleaning to be performed in-situ before the printhead is needed for printing, thereby eliminating downtime and the need for skilled manual cleaning operations
4Reliability
If cleaning liquid is used to dissolve ink deposits, then deposits are removed, but compatibility with printing ink is compromised
Solution Approach 1:
The patent changes the physical state and energy parameters of the cleaning liquid by applying ultrasonic vibration, transforming it from a passive solvent into an active cleaning medium that removes deposits through cavitation and mechanical agitation rather than chemical dissolution, thereby maintaining compatibility with printing ink
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 method provides thorough and intensive cleaning of both internal and external components of the printhead without requiring removal from the printing apparatus, ensuring compatibility with the ink and reducing the risk of damage, thus enhancing cleaning efficiency and reducing downtime.
Implementation Method 1
A maintenance cap with an ultrasonic transducer generating acoustic waves between 20kHz and 100kHz is used to create cavitation bubbles
Implementation Method 2
at least one transducer coupled to the housing for generating ultrasound acoustic waves in the liquid contained in the chamber and printhead
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A maintenance cap is provided for in-situ attachment to a printhead of printing apparatus. The maintenance cap comprises a housing defining at least one chamber for receiving a liquid. An opening in the housing provides a path for the liquid to pass from the chamber into a portion of the printhead when the maintenance cap is engaged with the printhead. The maintenance cap also includes a seal disposed around the opening for engagement with the printhead. A transducer coupled to the housing is used to generate ultrasound acoustic waves in the liquid contained in the chamber and printhead so as to clean the printhead.