Printer Sensor Calibration for Object Detection

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Solution Overview

Problem

Conveyor-based printers face challenges in reliably detecting objects and adjusting sensor sensitivity without operator intervention, particularly when dealing with varying conveyor and object reflectivities, leading to inconsistent print quality.

Innovation Solution

The printer incorporates a sensor calibration mode that automatically sets sensitivity levels by guiding the operator through background and object threshold determinations, storing these settings for future use, allowing for adaptive sensitivity adjustments based on conveyor and object types, thus eliminating the need for manual 'learn' button operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual sensor calibration using learn buttons is used, then sensor sensitivity can be adjusted, but operator intervention and setup time are required

Engineering Contradiction:
Improvesensor calibrationVSAvoidsetup time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The sensor calibration system performs automatic calibration without requiring operator intervention. The control unit automatically controls the sensor to determine background threshold sensitivity levels and object threshold sensitivity levels, eliminating the need for operators to manually press learn buttons and perform calibration procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs sensor calibration in advance during setup, storing the determined sensitivity levels for future use. This preliminary calibration action ensures that subsequent printing operations can proceed without repeated calibration, reducing ongoing setup time and effort.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If fixed sensor sensitivity is used, then device complexity is reduced, but adaptability to different conveyor and object types is limited

Engineering Contradiction:
Improvesensor sensitivity adjustmentVSAvoidsensor calibration system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The sensor sensitivity is made dynamic and adjustable rather than fixed. The control unit can control the sensor to determine different sensitivity levels (background threshold and object threshold) and store these for use with different conveyor and object types, allowing the system to adapt to varying conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the sensitivity parameter of the sensor based on detected conditions. By determining background threshold sensitivity levels and object threshold sensitivity levels, the system adjusts the sensor's operational parameters to optimize detection for different scenarios without requiring physical hardware changes.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If sensor sensitivity is increased to detect all objects, then detection reliability improves, but false detection of background increases

Engineering Contradiction:
Improveobject detectionVSAvoidfalse detection
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system uses feedback from the sensor to automatically adjust and determine appropriate sensitivity levels. By analyzing the sensor's detection of background conditions and object conditions, the control unit determines optimal threshold sensitivity levels that distinguish true objects from background, reducing false detections while maintaining reliable object detection.

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

This solution enhances print quality by ensuring consistent sensor sensitivity across different conveyor and object types, reducing setup time and effort, and maintaining accurate detection without operator calibration in subsequent uses.

Implementation Method 1

The sensors will usually be reflection type sensors, in which radiation is emitted from the sensor and the presence of an object is sensed by the detection of radiation reflected by the object

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

each sensor may be constructed as a light source and a photodetector positioned close together, so that the photodetector detects light originating from the light source and reflected by an object when the object is present

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP3463908B1Printer for printing onto a succession of objects
Publication Date: 2022.03.23 LINX PRINTING TECH
  • EP3463908B1 patent drawingFigure 1~3
  • EP3463908B1 patent drawingFigure 4~7
  • EP3463908B1 patent drawingFigure 8

AI summary

A non-contact printer controls the sensitivity of sensors (31) provided upstream of a print head (5), to detect the approach of an object (11) to be printed onto. In a calibration operation to set the sensitivity level of the sensors before a printing operation, the printer displays instructions to guide the operator and adjusts the sensor sensitivity to find detection threshold levels for a background (object absent) condition and when the object is present. The calibration results can be stored in association with data identifying the conveyor (13) and the type of object used in the calibration operation. If the same conveyor and/or object type is used again in a later printing operation, the sensitivity level of the sensors can be set using the stored calibration results so that a further calibration operation is not necessary.