Reflective and Transmissive Sensor System for Ribbon Registration Mark Detection

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Solution Overview

Problem

Conventional optical sensors often misidentify non-registration marks on printer ribbons as registration marks, leading to misalignment issues during the printing and transfer processes, which can result in defective credential products.

Innovation Solution

A sensor system combining a reflective sensor and a transmissive sensor is used to accurately detect registration marks on a transfer ribbon, with the reflective sensor identifying marks by analyzing reflected electromagnetic energy and the transmissive sensor determining the mark's location by analyzing transmitted energy, thereby reducing misidentification and ensuring precise alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional optical sensor is used to detect registration marks, then the detection process is simple, but the sensor misidentifies non-registration marks as registration marks, leading to misalignment

Engineering Contradiction:

Improveregistration mark detection accuracyVSAvoidsensor system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor system is divided into two separate sensor types: a reflective sensor for detecting the presence of registration marks and a transmissive sensor for determining their precise location. This segmentation allows each sensor to perform its specialized function optimally, resolving the contradiction between detection accuracy and system simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The controller acts as an intermediary that receives signals from both the reflective sensor and transmissive sensor, processes the combined information, and determines the final registration mark location. This intermediary coordination enables accurate mark identification while maintaining systematic organization.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If a single sensor is used to detect registration marks, then the device complexity is low, but the alignment precision deteriorates due to misidentification of marks

Engineering Contradiction:

Improveprint section alignment precisionVSAvoidsensor configuration complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The detection function is segmented between two sensor types positioned at different locations. The reflective sensor detects marks on one side of the ribbon while the transmissive sensor detects marks through the ribbon from the opposite side, enabling precise alignment without requiring a single complex sensor.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The reflective sensor and transmissive sensor are merged into a coordinated detection system where both sensors work together under controller management. This combination provides complementary information that significantly improves alignment precision compared to using either sensor alone.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If the reflective sensor is positioned upstream of the transmissive sensor, then the detection sequence is simplified, but the system requires precise positioning to maintain detection accuracy

Engineering Contradiction:

Improvedetection sequence simplicityVSAvoidmark location detection accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The reflective sensor performs preliminary detection of registration marks upstream before the transmissive sensor provides final location verification downstream. This preliminary action simplifies the overall detection sequence while maintaining precision through the subsequent confirmatory measurement.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The controller uses feedback from both sensors to verify registration mark detection. The upstream reflective sensor provides initial detection feedback, and the downstream transmissive sensor provides confirmatory feedback, ensuring both operational simplicity and measurement precision.

Inventive Principle:

Principle #23Feedback

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 sensor system effectively distinguishes registration marks from other printed marks, enhancing the accuracy of print section alignment with the print head and transfer device, thereby improving the precision and quality of credential production.

Implementation Method 1

the reflective sensor identifying marks by analyzing reflected electromagnetic energy

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

the transmissive sensor determining the mark's location by analyzing transmitted energy

Methodology Applied

Scientific EffectTransmission:

Data Source

PatentEP3147132B1Sensor for identifying registration marks on a ribbon

Publication Date: 2020.04.29 ASSA ABLOY AB

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AI summary

In a method of detecting a location of a print section of a transfer ribbon (106), the transfer ribbon is fed in a feed direction relative to a print section sensor. The print section sensor includes a reflective sensor (166) and a transmissive sensor (168). The reflective sensor is positioned upstream of the transmissive sensor relative to the feed direction. A registration mark on the transfer ribbon (106), which indicates the location of the print section on the transfer ribbon, is detected using the reflective sensor. The registration mark is detected using the transmissive sensor. The location of the print section is determined based on the detection of the registration mark using the transmissive sensor.