Printhead Cross-Process Control for Dynamic Alignment Errors
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Solution Overview
Problem
High-speed continuous web printing systems face dynamic alignment errors due to thermal expansion and contraction of printheads and rolls, which are not effectively corrected by existing alignment procedures, limiting image clarity.
Innovation Solution
A method and system that control the cross-process position of printheads using a control system with an image registration and color control board, which detects registration marks, performs a least squares fit to analyze dynamic errors, and adjusts the printhead positions to compensate for these errors, thereby reducing dynamic alignment issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed continuous web printing is performed, then productivity increases, but dynamic alignment errors worsen due to thermal expansion and contraction of printheads and rolls
Solution Approach 1:
The system continuously monitors the actual positions of printheads and web using sensors and registration marks, compares them with desired positions, and dynamically adjusts printhead positions to compensate for thermal expansion and contraction errors that occur during high-speed printing
Solution Approach 2:
The alignment system transitions from static pre-printing alignment to dynamic real-time alignment control, where printhead positions are continuously adjusted during the printing process to compensate for thermal effects that vary with operating conditions and speed
2Device complexity
If existing alignment procedures are used, then device complexity is kept simple, but alignment precision is insufficient to correct dynamic errors
Solution Approach 1:
The control system uses feedback from sensors detecting registration marks to continuously monitor and adjust printhead positions, providing real-time correction of dynamic alignment errors without requiring overly complex mechanical alignment mechanisms
Solution Approach 2:
The system replaces complex mechanical alignment mechanisms with a control-based approach using sensors, processors, and actuators that dynamically adjust printhead positions through electronic control rather than mechanical realignment
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
The solution effectively reduces dynamic alignment errors, improving image clarity and resolution by accurately aligning printheads with the web, even under high-speed operation and varying thermal conditions.
Implementation Method 1
dynamic alignment errors due to thermal expansion and contraction of printheads and rolls
Implementation Method 2
dynamic alignment errors due to thermal expansion and contraction of printheads and rolls
Data Source
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AI summary
A system and method for controlling the cross-process position of ink print heads including identifying a first roll error frequency related to a circumference of a first roll, identifying a first roll error phase with respect to a reference location along a process path, identifying a first roll error amplitude of cross-process motion, identifying a second roll error frequency related to a circumference of a second roll, identifying a second roll error phase with respect to the reference location, identifying a second roll error amplitude of cross-process motion, and controlling the cross-process position of a first and second print head based upon the identified first roll error frequency, first roll error phase, first roll error amplitude, second roll error frequency, second roll error phase, and second roll error amplitude, wherein the first print head is axially spaced apart from the second print head along the process direction.