Master-Slave Printing Press Synchronization for Web Alignment
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Solution Overview
Problem
Printing variable content onto multiple webs intended for combination into target products faces challenges due to differences in web convergence locations and imperfect calibration of positional encoders across digital printing presses, leading to spatial divergence and accumulation of errors.
Innovation Solution
The solution involves synchronizing multiple printing presses by designating a 'master' press and a 'slave' press, where the slave press begins printing based on the timing of the master press and the distances between each press and the web convergence location, effectively resetting encoder errors at each frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple digital printing presses operate independently with their own positional encoders, then each press can print variable content on its web, but spatial divergence and error accumulation occur between frames from different presses
Solution Approach 1:
A master printing press serves as an intermediary reference for slave printing presses. The master press's encoder readings are communicated to slave presses, which use these readings to synchronize their frame printing timing. This intermediary reference system eliminates spatial divergence and error accumulation by providing a common temporal and spatial reference frame for all presses, ensuring accurate frame alignment when webs are combined.
2Productivity
If webs from multiple presses are fed at the same velocity, then feeding efficiency is maintained, but encoder calibration differences cause perceived velocity variations and error accumulation
Solution Approach 1:
Slave printing presses receive feedback regarding the master press's encoder readings and use this information to adjust their frame printing timing. This feedback mechanism compensates for encoder calibration differences between presses, allowing webs to be fed at the same velocity for efficiency while preventing error accumulation through continuous synchronization based on the master press's actual encoder measurements.
3Ease of operation
If slave press begins printing without synchronization, then printing operation is simple, but frames from different presses arrive at finishing unit at different times causing misalignment
Solution Approach 1:
Slave printing presses perform preliminary actions by calculating and setting their frame printing timing in advance based on the master press's encoder readings and the known distance each web travels to the finishing unit. This preliminary synchronization ensures that frames from different presses arrive at the finishing unit at the correct time without requiring complex real-time adjustments, maintaining operational simplicity while achieving precise frame alignment.
Data Source
AI summary
In various examples, a master press and a slave press may be synchronized. A signal associated with the master press printing a first frame on a first web may be received. A point in time may be determined at which the slave press should begin printing, on a second web, a second frame corresponding to the first frame. The determining may be based on the signal associated with the master press and a first distance between the slave press and a downstream location at which the first and second webs converge. The slave press may be operated to begin printing the second frame at the point in time.