Printhead Nozzle Trajectory Detection via Optical Sensing
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Solution Overview
Problem
As the number of nozzles per printhead increases, detecting improperly functioning nozzles in inkjet printers becomes more difficult, leading to degraded image quality due to misdirected ink drops.
Innovation Solution
An optical sensor system with a movable carriage, light emitter, and light detector is used to test each nozzle by analyzing the trajectory of ink drops intersecting with a light beam, allowing for identification and potential replacement of faulty nozzles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of nozzles per printhead is increased, then the printing resolution and density are improved, but the difficulty of detecting improperly functioning nozzles increases
Solution Approach 1:
The detection system segments the detection process by using a movable carriage that positions a light beam individually at each nozzle location. This allows the system to divide the complex task of detecting hundreds of nozzles into separate, manageable measurement points, enabling precise trajectory analysis for each nozzle without being overwhelmed by the high density of nozzles
Solution Approach 2:
The patent introduces an optical sensor system with a light beam as an intermediary to detect ink drop trajectories. Instead of directly monitoring each nozzle, the system uses light scattering/absorption by ink drops as a mediator to indirectly measure trajectory accuracy, making detection feasible for high-density nozzle arrays
2Quantity of substance
If the number of nozzles per printhead is increased, then the printing density is improved, but the image quality degrades due to misdirected ink drops
Solution Approach 1:
The system performs preliminary detection of nozzle performance before actual printing occurs. By testing each nozzle's trajectory using the optical sensor system and identifying misdirected nozzles in advance, the system can prevent defective nozzles from degrading image quality during normal printing operations
Solution Approach 2:
The optical sensor system provides feedback about nozzle performance by measuring light scattering/absorption patterns that indicate trajectory accuracy. This feedback mechanism allows the system to identify and correct misdirected nozzles, maintaining image quality even as printing density increases
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 effectively determines the proper trajectory of ink drops, enabling the detection and correction of misfiring nozzles, thereby maintaining image quality even with high-density nozzle arrays.
Implementation Method 1
a beam of light is positioned to intersect with a nozzle of the printhead such that ink ejected by the nozzle will intersect with the beam of light
Data Source
AI summary
A system and method for testing printheads is disclosed. The system comprises an optical sensor mounted on a movable carriage. The optical sensor is moved past a nozzle to be tested on the printhead while the nozzle ejects ink. The output signal of the optical sensor can be used to determine when the trajectory of the ejected ink is improper.