Relative Height Sensing for Printing Machine Tooling Pins
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Solution Overview
Problem
Existing component height sensing systems in printing machines face challenges in accurately measuring the height of tooling pins due to debris or contamination on the tooling table, leading to measurement errors and potential print defects.
Innovation Solution
A component height sensing system that measures relative component heights instead of absolute heights, using a height sensor to determine the relative heights of at least three component locations and a control means to analyze these measurements and identify height deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If absolute height measurement of tooling pins is performed using a distance sensor, then the height of each pin can be measured, but measurement errors occur due to debris or contamination on the tooling table
Solution Approach 1:
The patent extracts the harmful reference (tooling table surface) from the measurement system by measuring only the relative heights between pins themselves, rather than measuring each pin's absolute height from the contaminated table surface. This removes the debris-contaminated reference plane from influencing measurements.
Solution Approach 2:
The patent introduces an intermediary reference system where the pins themselves serve as mutual references. Instead of using the contaminated table as the reference, each pin's height is determined relative to other pins, creating a self-referencing measurement system that bypasses the contaminated reference plane.
2Loss of information
If the tooling table surface is used as a reference for height measurement, then absolute height values can be obtained, but measurement accuracy deteriorates due to table non-planarity and debris
Solution Approach 1:
The patent removes the flawed reference system (tooling table surface) from the measurement process entirely. By measuring relative heights between pins without referencing the table surface, the system extracts only the necessary measurement information (pin height differences) while eliminating the corrupt reference data.
Solution Approach 2:
Instead of measuring pins relative to the table (table-as-reference approach), the patent inverts the reference relationship by measuring pins relative to each other (pin-as-reference approach). This inversion makes the measurement system immune to table surface defects.
3Productivity
If automated pin placement systems are used, then productivity increases, but the risk of pin placement errors on contaminated areas increases
Solution Approach 1:
The patent implements a feedback mechanism where relative height measurements are taken after pin placement, and pins with abnormal relative heights (indicating placement on debris) are identified and can be corrected. This closed-loop feedback maintains reliability while preserving automation benefits.
Solution Approach 2:
The patent performs preliminary height verification measurements after pin placement but before the printing process. This preliminary detection of misplaced pins allows for correction before contamination affects the actual printing operation.
Data Source
AI summary
Heights of components or parts thereof are measured within a printing machine by measuring their relative rather than absolute heights. A virtual surface may be constructed from the measured heights, with a tolerance level employed based on the virtual surface. The invention is particularly suited to measurement of tooling components within a printing machine, such as tooling pins.