Sense Mark Detection for High-Speed Printing Alignment
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Solution Overview
Problem
High-speed printing systems face challenges in accurately tracking the position of a paper web and controlling printheads due to the paper's high speed and dimensional changes, leading to inaccuracies in image alignment and requiring a larger paper web width for printing.
Innovation Solution
A printing system that includes a single sensor associated with multiple printheads around a drum to detect a sense mark on the paper web, allowing the controller to distribute print data among the printheads accurately, enabling precise image alignment and printing across the entire web width, including the area where the sense mark is located.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a first printhead on a first imaging unit is used to print the sense mark on the paper web, then the sense mark can be printed and detected, but a larger paper web width is required due to the unused margin where the sense mark is printed
Solution Approach 1:
The sense mark printing function is extracted from the imaging units and assigned to a separate sense mark printer. This allows the sense mark to be printed in a dedicated area without consuming valuable imaging unit capacity and without requiring additional paper web width beyond what is needed for the actual print images.
Solution Approach 2:
A separate sense mark printer acts as an intermediary component between the paper web feed and the imaging units. This mediator prints the sense mark in a controlled manner that does not interfere with the imaging units' print areas, thereby optimizing paper web utilization.
2Measurement precision
If multiple sensors are used to detect the sense mark at different positions, then detection accuracy may improve, but device complexity increases
Solution Approach 1:
Multiple sensing functions are merged into a single sensor located at the drum position. The sensor detects sense marks from multiple printheads simultaneously, eliminating the need for separate sensors for each printhead while maintaining comprehensive detection capability across the entire print width.
Solution Approach 2:
The single sensor at the drum position serves multiple functions: it detects sense marks for multiple different printheads, tracks paper web position, and provides feedback for controlling the entire imaging unit. This multi-functional approach reduces overall system complexity while maintaining detection accuracy.
3Productivity
If the paper web moves at high speed through the printing system, then productivity increases, but accurate tracking of paper web position and control of printheads becomes difficult
Solution Approach 1:
The sensor detects the position of sense marks on the moving paper web and provides real-time feedback to the controller. The controller uses this feedback information to dynamically adjust printhead positioning and timing, ensuring accurate image alignment even at high printing speeds where paper web position can vary due to moisture and other forces.
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 solution allows for accurate alignment and control of images on high-speed printing systems, reducing the need for a wider paper web and improving printing efficiency by using a separate sense mark printer and sensor to track the paper web's position and speed.
Implementation Method 1
a sensor associated with the plurality of printheads that detects the sense mark at a position where the substrate is in contact with the drum
Data Source
AI summary
A printing system includes a printer that prints only a sense mark on a substrate and an imaging unit. The imaging unit prints data onto the substrate and includes a plurality of printheads. The printing system also includes a sensor that detects the sense mark and a controller that instructs the imaging unit to print data onto the substrate, wherein the controller distributes print data among the plurality of printheads.