Printing Press Register Regulation Using Predictive Buffer Correction
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Solution Overview
Problem
Conventional printing presses face challenges in achieving precise register regulation due to significant spacing between printing units and sensor units, leading to slow regulating behavior and potential overshooting or instabilities in correcting printing position errors.
Innovation Solution
A method that uses a sensor unit to detect actual print mark positions, calculates deviations, and stores correction values in a memory buffer to continuously adjust the printing position, allowing for dynamic and stable register regulation, even with great spacings between printing units and sensor units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the sensor unit is arranged downstream of the last printing unit (end-of-line arrangement), then the spacing between printing unit and sensor unit is particularly great, but the regulating behavior becomes particularly slow
Solution Approach 1:
The patent applies preliminary action by predicting the printing position error before the printed copy physically reaches the sensor unit. The prediction is based on the measured position of previously printed copies and the known transport time. This allows the control system to prepare correction values in advance, compensating for the long spacing delay and achieving fast regulating behavior despite the great distance between printing unit and sensor unit.
2Measurement precision
If correction is performed only after printed copy reaches sensor unit, then measurement accuracy is ensured, but regulating behavior becomes slow and may cause overshooting
Solution Approach 1:
The system performs preliminary measurement and prediction of printing position errors before the actual printed copy reaches the sensor unit. By measuring previous copies and predicting future positions, the system prepares correction values in advance, ensuring both measurement precision and regulation reliability without overshooting.
Solution Approach 2:
The patent implements feedback by continuously measuring print mark positions, comparing them with target positions, and using the error information to adjust subsequent printing positions. The feedback loop incorporates prediction algorithms that account for transport delays, ensuring stable and accurate register regulation.
3Reliability
If boosting of regulator is decreased to prevent overshooting, then stability is improved, but regulating behavior becomes slower
Solution Approach 1:
By predicting printing position errors in advance based on previous measurements and transport time calculations, the system prepares correction values before they are needed. This eliminates the need to reduce regulator boosting, maintaining both fast regulating behavior and stability without overshooting.
Data Source
AI summary
An apparatus, a printing press and method for correcting the printing position of a printing unit of a printing press that has at least one sensor unit, where the method includes the steps of detecting an actual position of at least one print mark via the sensor unit, where the print mark is printed onto a printing material via the printing unit, determining of a deviation of the detected actual position from a setpoint position, determining at least one difference value that characterizes the deviation, determining a buffer value from a number of basic values previously stored in a memory, determining a correction value by subtracting the buffer value from the difference value, storing the determined correction value in the memory as one of the basic values, and correcting the printing position based on the determined correction value.