Print Head Alignment via Optical Detection and Simultaneous Adjustment
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Solution Overview
Problem
Inkjet printing machines face challenges in maintaining precise alignment and synchronization of multiple print heads to achieve high-quality, register-accurate prints, especially in multi-color printing, due to complex processes and devices required for geometric positioning and droplet ejection timing.
Innovation Solution
A method that divides the adjustment process into partial and overall detection processes, using optical sensors to record and adjust relative settings such as geometric positioning and droplet ejection times across multiple print heads, allowing for simultaneous detection and adjustment of settings to optimize print head alignment and timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complex processes and devices are used for aligning and synchronizing multiple print heads, then registration accuracy is improved, but device complexity and operational complexity increase
Solution Approach 1:
The patent replaces complex mechanical alignment devices with an optical detection system. A single sensor detects the positions of multiple print heads by reading markings on a continuously moving transport element, eliminating the need for complex mechanical positioning devices and procedures.
Solution Approach 2:
The transport element serves multiple functions: it transports the printing material and simultaneously carries alignment markings that enable detection of multiple print head positions. This single element performs both material handling and alignment reference functions.
2Manufacturing precision
If sequential adjustment of print heads is performed, then alignment precision is maintained, but adjustment time increases
Solution Approach 1:
The patent performs preliminary detection of all print head positions simultaneously in one pass of the sensor along the transport element. This preliminary action captures all alignment data before any adjustments are made, enabling parallel processing of alignment information.
Solution Approach 2:
The system uses feedback from the sensor readings to calculate and apply corrections to multiple print heads simultaneously. The detected positions are processed to determine adjustment amounts, and all adjustments are implemented based on this unified feedback information.
3Measurement precision
If multiple sensors are used to detect print head positions, then detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The transport element acts as an intermediary that carries alignment markings visible to the sensor. Instead of using multiple sensors to directly detect print head positions, a single sensor detects markings on the transport element, which indirectly provides information about all print head positions.
Solution Approach 2:
The alignment markings on the transport element serve as a copy or representation of the desired print head positions. The sensor reads this copied information from the transport element rather than directly measuring each print head, simplifying the detection system.
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 method saves time while ensuring optimized print quality by allowing for rapid, simultaneous detection and adjustment of multiple print heads, leading to improved registration accuracy and reduced operational complexity.
Implementation Method 1
using optical sensors to record and adjust relative settings
Data Source
Figure 1a
Figure 1b
Figure 2a
AI summary
The invention relates to a method for adapting settings, which are relative to each other, of printing heads of a printing unit of a printing machine, wherein data regarding settings, which are relative to each other, of at least two printing heads belonging to a first subset of printing heads are detected in a first partial detection process and wherein data regarding settings, which are relative to each other, of at least two printing heads belonging to a second subset of printing heads and not belonging to the first subset are detected in a second partial detection process and wherein data regarding at least one setting of at least one first printing head of the first subset and of at least one second printing head of the second subset, which settings are relative to each other, are detected in a complete detection process and wherein at least the first partial detection process and the second partial detection process proceed at least partially simultaneously and wherein at most either the complete detection process proceeds or the first partial detection process and/or the second partial process proceeds at each point in time in the course of method and wherein the settings, which are relative to each other, of at least two of the printing heads are changed in an adjusting process. The invention further relates to a printing machine.