Inkjet Precoat Jet Detection Using Diagnostic Print Patterns
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Solution Overview
Problem
Existing aqueous inkjet printing systems face challenges in maintaining image quality on uncoated porous media due to ink absorption, and there is a need for effective detection of missing or misdirected jets in precoat solution application systems to ensure uniformity and placement on print media.
Innovation Solution
A method involving diagnostic media with predetermined patterns is used to detect missing or misdirected jets by firing precoat solution and ink droplets, capturing images, and analyzing patterns to identify and correct printhead defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If precoat solution is applied to uncoated porous media, then ink absorption is reduced and image quality is improved, but detection of missing or misdirected jets becomes difficult
Solution Approach 1:
A diagnostic sheet with a trigger pattern acts as an intermediary between the precoat solution application and the detection system. The trigger pattern is specifically designed to be detectable by the scanner, enabling indirect detection of precoat application quality through the interaction of ink droplets with the diagnostic sheet surface.
Solution Approach 2:
The diagnostic sheet utilizes color changes or optical property changes when ink droplets interact with the precoat solution. The scanner detects these changes to identify missing or misdirected jets, converting an invisible precoat defect into a detectable optical signal.
2Measurement precision
If diagnostic sheets with trigger patterns are used, then jet detection accuracy is improved, but media processing complexity increases
Solution Approach 1:
The trigger pattern is pre-configured on the diagnostic sheet before it enters the printing system. This preliminary preparation enables the scanner to automatically recognize when a diagnostic sheet is present and initiate the appropriate detection sequence, simplifying the overall processing despite the added pattern complexity.
3Productivity
If inline scanning is implemented for real-time detection, then productivity is improved, but system complexity increases
Solution Approach 1:
The inline scanner serves multiple functions: it detects the trigger pattern to identify diagnostic sheets, captures images of the printed patterns for analysis, and provides real-time feedback on precoat application quality. This multi-functionality justifies the added system complexity by consolidating multiple detection and control functions into a single device.
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 allows for quick and accurate identification of printhead issues, ensuring uniform precoat application and improved image quality on both coated and uncoated papers, enhancing print quality and de-inking capabilities.
Implementation Method 1
Aqueous ink printing onto uncoated, porous media, however, produces washed out, poorer quality images because the inks are absorbed into the fibers of the paper. To avoid this consequence, coatings can be applied to porous media to reduce the absorption of the inks into the media.
Implementation Method 2
capturing an image of a printed pattern on the diagnostic media
Data Source
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AI summary
A method for detecting missing or misdirected jets in a drop on demand delivery system for media priming in an inkjet printing application includes passing a diagnostic media in proximity to a first printhead may include a plurality of ejector jets. The method includes firing each of the plurality of jets onto the diagnostic media to deposit a precoat solution onto the diagnostic media in a first predetermined pattern, followed by depositing a plurality of droplets of at least one ink compositions onto the diagnostic media in a second predetermined pattern. An image of the diagnostic sheet can be captured and the printed pattern analyzed to detect missing or misdirected jets of a printhead configured to deposit a precoat solution or a primer solution.