Inkjet Detection via Light-Transmitting Substrate
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Solution Overview
Problem
In three-dimensional printing, inoperative inkjets in printheads can cause malformation of objects, and detecting these issues during production is challenging, especially with clear materials and inks, leading to inefficient production and scrap of printed objects.
Innovation Solution
A printer system that includes a light source and optical sensor to detect inoperative inkjets by projecting light onto a light-transmitting substrate and analyzing the reflected light to identify deviations in material ejection patterns, allowing for real-time detection and corrective action during the printing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If clear materials and inks are used in printheads, then the aesthetic quality and versatility of printed objects are improved, but the detectability of inoperative inkjets deteriorates due to low contrast between clear inks and substrates
Solution Approach 1:
A light-transmitting substrate acts as an intermediary between the clear ink and the detection system. The substrate allows light to pass through it and the clear ink, enabling optical detection of ink ejection patterns that would otherwise be invisible against the substrate background.
Solution Approach 2:
The system utilizes optical property changes - specifically light transmission and refraction variations - rather than color contrast. The clear ink and substrate interact with light differently, creating detectable optical signatures that indicate proper or defective ink ejection without requiring visible color contrast.
2Device complexity
If inoperative inkjets are detected only after printing completion, then the simplicity of the printing system is maintained, but the productivity and resource efficiency deteriorate due to scrap and re-printing
Solution Approach 1:
The detection system performs preliminary detection of inkjet operational status during the printing process itself, rather than after completion. This allows for real-time identification of inoperative inkjets, enabling corrective action before the entire print job is completed and potentially ruined.
Solution Approach 2:
The system implements feedback by continuously monitoring ink ejection patterns during printing and providing real-time information about inkjet operational status. This feedback loop enables dynamic adjustment or intervention to prevent production of defective objects.
3Measurement precision
If light is projected onto the substrate to enable detection, then the measurement precision of inkjet operation is improved, but the device complexity increases due to additional optical components
Solution Approach 1:
The optical sensor creates an optical copy or image of the ink ejection pattern on the substrate. This optical copy captures the refraction light patterns that indicate proper or defective inkjet operation, allowing detection without direct physical contact or complex mechanical measurement systems.
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
Enables real-time detection of inoperative inkjets, improving product yield and printing efficiency by allowing for restorative procedures during object production, reducing the need for scrapping and re-printing of malformed objects.
Implementation Method 1
a light source positioned to direct light into the edge of the substrate, an optical sensor positioned to receive light emitted by the surface of the substrate
Implementation Method 2
use of the light-transmitting substrate in the printhead assembly
Data Source
AI summary
An apparatus detects inoperative inkjets during printing. The apparatus includes a light transmitting substrate onto which a test pattern of material is ejected. A light source directs light into the substrate and an optical sensor generates image data of a surface of the substrate. Light propagates through the substrate unless it reaches a position where the material is present on the surface. Thus, the material emits light so a contrast exists between the surface of the substrate and the material emitting light. By comparing the image data to the positions of the light emitting areas on the surface, inoperative inkjets are detected.