Curved Surface Printing with Timing Mark Sensor Positioning

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Solution Overview

Problem

Existing thermal printers face difficulties in printing precise machine-readable information, such as barcodes, on curved surfaces with dimensional inconsistencies and surface anomalies, common in injection-molded plastic test tubes, due to challenges in maintaining physical and thermal contact between the print head and the surface.

Innovation Solution

A method and device that control the printing process by using a timing mark sensor to detect the position of a timing mark on a label, allowing the print head to position itself accurately on the curved surface, and printing a timing mark modifier to indicate completion, ensuring precise image placement and readability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a thermal print head is used to print on curved surfaces, then printing capability is provided, but printing precision deteriorates due to inability to maintain consistent contact with dimensional inconsistencies and surface anomalies

Engineering Contradiction:
Improveprinting capabilityVSAvoidprinting precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The printing system employs dynamic adjustment mechanisms that allow the print head to adapt its position and contact pressure in real-time as the curved surface passes by. This enables consistent thermal contact despite variations in surface geometry, maintaining printing precision across dimensional inconsistencies and surface anomalies.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system modifies printing parameters such as print head temperature, contact pressure, and scanning speed dynamically based on detected surface characteristics. By changing these parameters in response to real-time surface variations, the system maintains optimal printing quality on irregular curved surfaces.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the print head maintains physical contact with the curved surface, then printing can be performed, but contact consistency deteriorates due to concave and convex portions on the surface

Engineering Contradiction:
Improveprinting operationVSAvoidcontact consistency
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system uses dynamic positioning and pressure adjustment mechanisms that continuously adapt to the curved surface profile. This allows the print head to maintain reliable thermal contact by compensating for concave and convex portions through real-time mechanical adjustments.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A compliant intermediary layer or mechanism is introduced between the rigid print head and the curved surface. This intermediary element deforms to conform to surface irregularities, ensuring consistent thermal contact across dimensional variations while transmitting printing forces effectively.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If printing is performed on small diameter cylindrical tubes, then identification capability is provided, but positioning accuracy deteriorates due to high curvature and surface irregularities

Engineering Contradiction:
Improveidentification capabilityVSAvoidpositioning accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system employs dynamic positioning control that adjusts the print head's spatial coordinates and orientation in real-time based on the detected curvature and position of the cylindrical tube. This enables accurate image placement despite high curvature and surface irregularities on small diameter tubes.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from sensors that detect the actual position and surface characteristics of the tube during printing. This feedback information is used to dynamically correct positioning errors and adjust printing parameters, ensuring accurate barcode placement on curved surfaces with dimensional variations.

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

Enables accurate and reliable printing of information on curved surfaces with irregularities, improving the readability of machine-readable codes like barcodes, even on small diameter cylindrical tubes with concave and convex portions, enhancing tracking and identification in laboratory and diagnostic processes.

Implementation Method 1

detecting a position of a timing mark on a label with a timing mark sensor

Methodology Applied
Scientific EffectOptical detection: Reflection

Implementation Method 2

a print head prints an image onto predetermined printable area of a label

Methodology Applied
Scientific EffectThermal printing: Heating

Data Source

PatentEP4056380B1Method and apparatus for printing on an object having a curved surface
Publication Date: 2024.04.03 GEN PROBE INC
  • EP4056380B1 patent drawingFigure 1
  • EP4056380B1 patent drawingFigure 2
  • EP4056380B1 patent drawingFigure 3

AI summary

There is disclosed a method for controlling a printing process by which a print head prints an image onto predetermined printable area of a label, the method comprising: (a) effecting relative movement between a timing mark sensor and the label; (b) during step (a), detecting a position of a timing mark with the timing mark sensor; (c) after step (b), effecting relative movement between the print head and the label to position the print head at an image position at a specified distance from the position of the timing mark detected in step (b); (d) activating the print head; (e) during step (d) effecting relative movement between the print head and the label for a specified image distance to print the image onto the printable area; and (f) printing a timing mark modifier that is detectable by the timing mark sensor onto the label to indicate that the label has been printed on.