Automated Time of Flight Speed Compensation for Inkjet Printers
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Solution Overview
Problem
Current high-speed, multi-color inkjet printing systems require manual adjustment of the Time of Flight (TOF)/Speed Compensation variable, which is inefficient and prone to errors due to variations in media transport speed, affecting color-to-color registration accuracy.
Innovation Solution
An automated method determines the speed compensation factor by printing and capturing images at different media speeds, using image analysis to calculate the actual time of flight displacement distance and adjust the compensation factor accordingly, ensuring accurate image placement on the print media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If manual adjustment of TOF/Speed Compensation variable is used, then operator control is maintained, but automation and efficiency are reduced
Solution Approach 1:
The system performs self-calibration by automatically determining the speed compensation factor through image capture and analysis, eliminating the need for manual operator intervention. The calibration process is executed autonomously by the printing system itself, allowing the system to service its own registration accuracy requirements.
Solution Approach 2:
The system performs speed compensation calibration in advance before actual printing operations. By capturing images at different media speeds and calculating the compensation factor beforehand, the system prepares the necessary correction data proactively, ensuring accurate registration is ready before production printing begins.
2Manufacturing precision
If manual adjustment of TOF/Speed Compensation variable is used, then simplicity is maintained, but precision and reliability are reduced
Solution Approach 1:
The system captures images of the print media at different speeds, analyzes the actual position of printed images using image analysis, and uses this feedback information to calculate and determine the accurate speed compensation factor. This closed-loop feedback mechanism ensures high registration precision by continuously measuring and correcting based on actual performance.
Solution Approach 2:
The patent replaces manual mechanical adjustment of compensation variables with an automated optical and computational system. Instead of manually turning knobs or entering values, the system uses image capture devices, automated image analysis, and computational algorithms to determine the speed compensation factor, substituting mechanical operations with optical and information-processing methods.
3Productivity
If speed compensation is not automated, then system complexity is reduced, but productivity and efficiency are reduced
Solution Approach 1:
The image capture device serves multiple functions: it captures images for quality control, measures actual image positions for calibration, and provides data for speed compensation determination. By making this single device multi-functional, the system achieves high productivity without proportionally increasing overall system complexity.
Data Source
AI summary
A method for determining a speed compensation factor includes the steps of transporting a media moving at first speed; printing a first image on the media using at least one printhead while moving at the first speed; capturing the first image in a first frame of an image capture device; transporting the media moving at a second speed different from the first speed; printing a second image on the media using the at least one printhead while moving at the second speed; capturing the second image in a second frame of the image capture device; determining using a change of position of the first image relative to the second image using automated image analysis; and inputting the determined change of position into a processor for computing the speed compensation factor from the determined change of position and a known difference in speed between the first and second speeds.