Printhead Maintenance Station Using Mist to Prevent Inkjet Drying
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Solution Overview
Problem
Inkjets in printheads, especially those ejecting aqueous inks, can dry or experience increased viscosity when not regularly used, leading to maintenance issues and ink wastage during printhead purging operations.
Innovation Solution
A printhead maintenance station with a receptacle and nozzles that emit a fluid mist at predetermined intervals to maintain a humidity level within a predetermined range, using a controller to manage the operation of pumps and valves for selective printhead maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inkjets are not used regularly, then printing operations can be performed continuously, but ink dries or viscosity increases in the nozzles
Solution Approach 1:
The system performs preliminary maintenance actions by moving printheads to maintenance stations before ink drying becomes problematic. The controller identifies when printheads should be maintained and automatically relocates them to maintenance stations, performing maintenance before complete drying occurs, thus preventing the need for purging and restoring ink flow.
Solution Approach 2:
The system extracts printheads from the printing position and relocates them to dedicated maintenance stations. This separation allows printing operations to continue with other printheads while extracted printheads receive maintenance, preventing ink drying in the extracted printheads and maintaining overall system productivity.
2Reliability
If printhead purging is performed to maintain inkjets, then inkjet operational status is restored, but ink is wasted
Solution Approach 1:
The system performs preliminary maintenance by relocating printheads to maintenance stations before ink drying occurs. This preventive approach avoids the need for purging operations that would waste ink, as the ink remains functional and can be used for printing without requiring complete purging and restoration.
Solution Approach 2:
The maintenance station automatically maintains printheads through automated processes including ink application and wiper blade cleaning. The system serves itself by automatically identifying when maintenance is needed and executing the maintenance routine without manual intervention, preventing ink wastage that would occur with traditional purging methods.
3Reliability
If all printheads are moved to maintenance stations, then ink drying is prevented, but printing productivity decreases
Solution Approach 1:
The system segments the printhead array into multiple groups and maintains them in batches. Instead of moving all printheads to maintenance stations simultaneously, the controller selectively moves only those printheads that require maintenance, while others continue printing. This segmentation maintains printing productivity while preventing ink drying in maintained printheads.
Solution Approach 2:
The system dynamically adjusts maintenance scheduling based on real-time conditions. The controller monitors printhead usage patterns and media dimensions, dynamically determining which printheads need maintenance and when. This dynamic approach ensures that printing operations continue with active printheads while maintenance is performed on inactive ones, balancing productivity and reliability.
4Adaptability or versatility
If media width is less than printhead module width, then smaller media can be printed, but inkjets at the ends are not operated and ink dries
Solution Approach 1:
The system performs preliminary maintenance actions on end inkjets before ink drying occurs. When media with reduced width are printed, the controller identifies which inkjets will remain inactive and schedules maintenance for those specific inkjets at maintenance stations, preventing ink drying before it becomes a problem while allowing continued printing operations.
Solution Approach 2:
The system applies different maintenance strategies to different regions of the printhead module. Instead of maintaining all inkjets uniformly, the controller identifies and maintains only the end inkjets that are most likely to dry when printing narrower media. This localized maintenance approach prevents ink drying in vulnerable regions while minimizing disruption to overall printing operations.
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
Maintains inkjet operational status without ink wastage by keeping ink viscosity optimal, allowing continuous printing without purging all printheads, and enabling selective maintenance of printheads.
Implementation Method 1
a first nozzle in the first receptacle, the first nozzle being configured to emit a first fluid mist onto the faceplate mated to the first receptacle
Implementation Method 2
a first humidity sensor within the first receptacle, the first humidity sensor being configured to generate a signal corresponding to a humidity level within the first receptacle
Implementation Method 3
supply a solvent to the first nozzle to maintain the humidity level within the first receptacle within the predetermined range of humidity levels that correspond to a drying rate of a liquid ejected by the first printhead
Data Source
AI summary
An inkjet printer includes a printhead maintenance station that emits a mist of fluid onto the faceplate of a printhead mated to a receptacle within the printhead maintenance station. A controller is configured to operate one or more nozzles within the receptacle at predetermined time intervals to maintain a film of a fluid mist on the printhead mated to the receptacle. Alternatively, the controller is configured to monitor a humidity level within the receptacle and operate one or more nozzles within the receptacle to maintain the humidity level within a predetermined range. When more than one nozzle is provided in the receptacle of either embodiment, the controller is further configured to operate the nozzles independently of one another.