Flatbed Printer Camera-to-Print Head Coordinate Mapping

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Solution Overview

Problem

Existing flatbed printers face inaccuracies in determining print head coordinates due to reliance on flat bed surface coordinates, leading to errors and reduced print quality.

Innovation Solution

A method that directly converts camera coordinates into print head coordinates using a mapping table, eliminating the need for flat bed surface coordinates and accounting for printer and camera defects, with the mapping table established through printing and analyzing a reference image with geometric patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If flat bed surface coordinates are used to determine print head coordinates, then the printing process can be performed, but coordinate determination accuracy deteriorates due to accumulation of transformation errors

Engineering Contradiction:
Improvecoordinate determination accuracyVSAvoidprint quality
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent extracts and eliminates the intermediate flat bed surface coordinate system from the coordinate transformation chain. By establishing a direct mapping between camera coordinates and print head coordinates, the method removes the source of accumulated transformation errors and achieves higher coordinate determination accuracy for improved print quality.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If multiple coordinate transformations are performed (camera to flat bed surface to print head), then coordinate mapping can be achieved, but error accumulation increases reducing print accuracy

Engineering Contradiction:
Improvecoordinate mapping capabilityVSAvoidprint head coordinate accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent removes the intermediate flat bed surface coordinate system from the transformation chain, establishing a direct mapping between camera coordinates and print head coordinates. This eliminates the accumulation of transformation errors while maintaining full coordinate mapping capability through a simplified single-step transformation.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If conventional coordinate transformation methods are used, then printing can be performed, but additional calibrations are required increasing process complexity

Engineering Contradiction:
Improveprinting efficiencyVSAvoidcalibration process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent performs a preliminary direct calibration between the camera and print head coordinate systems, storing the transformation parameters in a lookup table. This preliminary action eliminates the need for additional calibrations during operation, simplifying the process while maintaining high printing efficiency.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3085544B1Method for printing on a media object in a flat bed printing system
Publication Date: 2018.06.13 CANON PRODUCTION PRINTING NETHERLANDS BV
  • EP3085544B1 patent drawingFigure 1
  • EP3085544B1 patent drawingFigure 2
  • EP3085544B1 patent drawingFigure 3

AI summary

The invention relates to a method for printing on a media object supported by a flat bed of a printer, the printer comprising a print head and a camera above the flat bed, the method comprising the steps of detecting a media object on the flat bed surface of the printer by means of a digital camera image captured by the camera, deriving camera coordinates of the media object in the digital camera image, applying a direct transformation from the camera coordinates into print head coordinates of the media object without using coordinates of the flat bed surface, and printing a digital target image on the media object by ejecting recording material on the media object from the print head, the print head controlled according to the print head coordinates appropriate for the media object.