Printing Plate Mounter Using Microdot Reference Structures
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Solution Overview
Problem
Conventional methods for mounting printing plates on cylinders in multi-color printing face challenges in achieving high positional accuracy due to size variations in large-format plates, leading to inefficiencies in material usage and adhesive tape requirements, and visible seams when dividing images into smaller tiles.
Innovation Solution
The method allows for independent selection of reference structure positions on each color's printing plates, optimizing their number and size based on the image content, using a common coordinate system to ensure precise alignment, and employing sensors to detect reference marks on cylinders for accurate positioning, enabling the use of smaller plates and reducing material waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If large-format printing plates are used to cover the entire printing format, then the number of plates is reduced, but size variations in plate production lead to significant deviations in microdot positioning and reduced mounting accuracy
Solution Approach 1:
The invention divides the printing format into multiple smaller printing plates (tiles) rather than using a single large-format plate. Each smaller plate has its own reference structures (microdots) positioned with higher precision, eliminating the cumulative positioning errors that occur with large plates. The mounter system then automatically assembles these segmented plates with precise registration to form the complete image.
2Manufacturing precision
If printing plates are divided into smaller tiles to improve positioning accuracy, then mounting precision improves, but visible butting seams appear in the printed image
Solution Approach 1:
The invention introduces reference structures (microdots and reference marks) as intermediary elements that facilitate precise alignment between adjacent printing plates. These reference structures serve as mediators that enable the mounter system to register plates with sub-millimeter accuracy, eliminating visible butting seams. The reference structures are strategically positioned to ensure seamless joining of plate edges while maintaining high positioning precision.
3Ease of operation
If the same number and size of printing plates are used for all color separations, then the mounting process is simplified, but printing plate material and adhesive tape are wasted when certain colors occupy only small portions of the format
Solution Approach 1:
The invention applies local quality by allowing each color separation to have a customized number and size of printing plates based on the actual image content requirements. Instead of uniformly applying the same plate configuration to all colors, the system optimizes plate usage locally for each color deck, reducing material waste while maintaining operational simplicity through automated mounting procedures.
4Manufacturing precision
If printing plates are manually adjusted to align microdots with target marks, then positional accuracy can be achieved, but the process is time-consuming and labor-intensive
Solution Approach 1:
The invention replaces the manual mechanical adjustment process with an automated optical-mechanical system. The mounter is equipped with cameras that capture images of microdots and reference marks, and a control system that automatically calculates and executes the precise positioning of each printing plate. This substitution of manual operations with automated vision-based positioning dramatically reduces mounting time while maintaining or improving alignment accuracy.
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 positional accuracy, reduces printing plate and adhesive tape costs, and mitigates size variation issues, while allowing for flexible plate configurations that adapt to image content, improving overall printing efficiency and image quality.
Implementation Method 1
a sensor which can detect this reference mark and can measure the longitudinal and angular offset of the reference mark relative to the cameras in the mounter
Implementation Method 2
The mounter has two cameras each of which defines a target position for one of the microdots and captures an enlarged image of the microdot and its surroundings
Data Source
AI summary
A method of mounting printing plates (28) on a plurality of cylinders (42) for multi-colour printing, comprising the steps of: a) determining, for each colour, a number of printing plates to be mounted on a corresponding cylinder (42), b) specifying coordinate positions for at least two reference structures (32) on each printing plate, c) forming the reference structures at the specified coordinate positions on the printing plates, d) installing one of the cylinders (42) in a mounter (40) having two cameras (58), e) adjusting the cameras (58) to the specified coordinate positions for one of the printing plates (28) and mounting the printing plate on the cylinder (42) in a position where each reference structure (32) is included in an image (68) captured by one of the two cameras and is aligned with a target mark (70) that corresponds to the specified coordinate position, f) repeating step (e) for each printing plate to be mounted on the cylinder, and h) repeating steps (d) to (f) for each cylinder.