Label Printing Camera Alignment for Slant-Free Print Placement

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Solution Overview

Problem

Existing label printing devices inaccurately detect label alignment, leading to suboptimal printing, such as slanted or offset prints, due to the use of color recognition sensors that generate a single, stationary light beam.

Innovation Solution

Employing a line or area scan camera to detect labels across their entire width and length, providing precise contour and orientation information, allowing for accurate alignment and printing adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a color recognition sensor with a stationary light beam is used to detect label position, then the device structure remains simple, but the label alignment detection precision deteriorates, resulting in slanted or offset printing

Engineering Contradiction:
Improvelabel alignment detection precisionVSAvoiddetection device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/optical color recognition sensor system with a camera-based detection system. The camera captures images of labels on the conveyor belt, and image processing algorithms determine label positions and orientations. This substitution enables precise detection of label alignment (resolving the measurement precision issue) while maintaining reasonable system complexity through software-based processing rather than complex optical-mechanical arrangements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates an optical copy (image) of the label using a camera instead of direct optical sensing. By capturing the entire label area and processing the image data, the system can determine label position, orientation, and dimensions more accurately than point-based sensors. This copying approach allows comprehensive label detection without requiring complex mechanical positioning systems.

Inventive Principle:
Principle #26Copying

2Measurement precision

If a single stationary light beam is used for label detection, then the detection device remains simple, but the detection accuracy deteriorates when labels are not perfectly aligned with the beam

Engineering Contradiction:
Improvedetection accuracyVSAvoidtolerance to label misalignment
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent transitions from one-dimensional point detection (single light beam) to two-dimensional area detection (camera field of view). The camera captures the entire label area, allowing detection of labels at various positions and orientations within the detection area. This dimensional expansion provides tolerance to misalignment by detecting labels across a broader spatial range rather than requiring precise alignment with a single beam.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The camera-based detection system serves multiple functions: detecting label presence, determining label position, measuring label orientation, and identifying label dimensions. This multi-functional approach replaces the single-function light beam sensor, providing adaptability to various label configurations and misalignment scenarios while maintaining a relatively simple detection device structure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If color recognition sensors are used for label detection, then the system operates simply, but printing quality deteriorates due to inaccurate label position detection

Engineering Contradiction:
Improveprinting qualityVSAvoiddetection system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements preliminary detection and measurement of label position and orientation before the printing process. The camera captures label images upstream, and image processing determines the exact label parameters. This preliminary action allows the printing system to adjust print positioning based on actual label alignment, ensuring high printing quality while using a detection system that is simpler than real-time optical feedback systems.

Inventive Principle:
Principle #10Preliminary action

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

Enables precise printing by capturing label edges and pre-printed areas, ensuring optimal placement of prints, and accommodating various label types, including transparent labels, with improved detection accuracy and reduced sensitivity to vibrations.

Implementation Method 1

When the light beam strikes a passing label, the light is reflected, and the reflection is detected by the color recognition sensor/luminescence switch

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3728054B1Apparatus and method for printing labels
Publication Date: 2025.12.31 ESPERA WERKE GMBH
  • EP3728054B1 patent drawingFigure 1
  • EP3728054B1 patent drawingFigure 2a~2b

AI summary

The invention relates to an apparatus for printing labels (1), in particular labels (1) provided on a carrier strip (2), comprising at least one label feeding device (3) for providing and delivering labels (1), a transport device (4) including at least one transport means (9, 10) for transporting the labels (1) fed by the label feeding device (3) in a transport direction (4), a printing device (11) including a print head (11a) for printing the labels (1) transported by the transport device (4), and a detection device (12) for detecting the position of the respective label (1) in a section of the transport device (4). According to the invention, the detection device (12) has a line scan camera or area scan camera (13) by which, when the camera is used as intended, the side of the transport means (9, 10) facing the labels (1) and/or a gap (19) formed in the transport direction between two transport means sections (17, 18) can be optically detected in a detection region (14).