Inkjet Printing Alignment via Real-Time Mark Inspection
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Solution Overview
Problem
In multicolor inkjet printing on containers, deviations in container positioning lead to unwanted offsets of individual printing colors, compromising the quality of the finished printed motif, and existing methods either require separate test containers, complex analysis, or delayed correction.
Innovation Solution
A method involving joint printing of a motif layer and a print mark in a first color, followed by mechanical optical inspection, alignment, and overprinting, allowing for real-time optimization of print quality and position, using registration and color marks that can be concealed in the final image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate printheads print individual inks sequentially, then multicolor printing is achieved, but positioning deviations cause misalignment of inks
Solution Approach 1:
The patent applies preliminary action by printing registration marks and test patterns before the actual production printing. These preliminary marks are used to detect positioning deviations and calculate correction values that are applied to subsequent printing operations, preventing misalignment before it occurs.
Solution Approach 2:
The patent implements feedback by using inspection units to detect the actual positions of registration marks printed by separate printheads. The detected positioning deviations are fed back to the control unit, which calculates correction values and adjusts the printing parameters of subsequent printheads to compensate for the deviations.
2Measurement precision
If test samples are printed and inspected separately, then print quality can be checked, but separate test containers are required
Solution Approach 1:
The patent merges the test pattern printing with the regular production printing by incorporating registration marks and test patterns directly into the motifs printed on the actual product containers. This eliminates the need for separate test containers while still enabling print quality inspection.
Solution Approach 2:
The registration marks serve multiple functions: they are used for alignment during printing, for quality inspection, and for calculating correction values. This multi-functionality eliminates the need for dedicated test samples while maintaining comprehensive quality control.
3Manufacturing precision
If correction is performed after complete multicolor printing, then print quality can be adjusted, but correction is delayed
Solution Approach 1:
The patent performs correction calculations and adjustments in advance by detecting positioning deviations from registration marks and calculating correction values before completing the entire multicolor printing process. These correction values are applied to subsequent printing operations, enabling real-time correction rather than delayed correction after printing is complete.
4Manufacturing precision
If printing parameters are changed based on relief-like surface contours, then print quality can be corrected, but characteristic printing features are required
Solution Approach 1:
The patent segments the printing system into independent printheads that can be individually adjusted. Each printhead's positioning and printing parameters can be corrected independently based on registration mark detection, without requiring characteristic features on the container surface itself.
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 approach enhances print quality by enabling real-time alignment and correction of subsequent colors, improving machine performance and final appearance by simplifying inspection and concealing print marks within the finished design.
Implementation Method 1
machine optical inspection of the at least one print mark
Data Source
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AI summary
A method and a device for multiple-colour inkjet printing on containers are described. Accordingly, a common print of a motif and at least one printing mark which is arranged, in particular, within the motif firstly takes place in a first printing ink on the containers. Subsequently, the at least one printing mark is optically inspected by machine. Following this, the containers are oriented in a manner which is based on said inspection, and the motif and, in particular, the printing mark are printed in a following printing ink. Finally, the printing mark is overprinted. As a result, direct checking of the printing operation and orientation of individual printing inks with respect to one another are possible during continuous printing operation without the use of additional test containers or the like.