Digital Printing Speed Control via Conveyor Feedback

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Solution Overview

Problem

Existing digital printing technologies face challenges in achieving high precision and quality, particularly with single-pass processes, due to fluctuations in conveyor speed and difficulties in guiding workpieces transversely, leading to issues like white stripes and overprinting on edges.

Innovation Solution

A printing device with stationary digital print heads and a detection system that adjusts printing speed based on actual workpiece speed, combined with a guide device for precise lateral guidance, ensures consistent and high-quality printing across the X and Y directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If single-pass printing process is used to achieve high printing speed, then productivity is improved, but manufacturing precision deteriorates due to conveyor speed fluctuations

Engineering Contradiction:
Improveprinting speedVSAvoidprint quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

A detection device detects the actual position or speed of the workpiece on the conveyor, and this information is fed back to control the printing process. The control device adjusts the droplet emission timing based on the detected workpiece position, compensating for conveyor speed fluctuations and maintaining print quality during high-speed single-pass printing.

Inventive Principle:
Principle #23Feedback

2Productivity

If tape transport is used to convey workpieces continuously, then productivity is improved, but manufacturing precision deteriorates due to inability to precisely guide workpiece transversely

Engineering Contradiction:
Improvecontinuous printing capabilityVSAvoidtransverse positioning accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

A guide device is introduced as an intermediary between the conveyor and the workpiece. This guide device precisely guides the workpiece in the transverse direction during conveyance, enabling accurate positioning without compromising the continuous printing capability provided by the conveyor system.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If fixed droplet emission frequency is used to simplify printing control, then device complexity is reduced, but manufacturing precision deteriorates due to speed fluctuations affecting print quality

Engineering Contradiction:
Improveprinting control systemVSAvoidprint quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The droplet emission frequency is made dynamic rather than fixed. The control device continuously adjusts the droplet emission timing based on real-time detection of workpiece position or speed, allowing the printing system to adapt to varying conveyor speeds and maintain print quality without excessive complexity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2718108B1Method for printing items and printing assembly
Publication Date: 2016.08.17 HYMMEN GMBH MASCH UND ANLAGENBAU
  • EP2718108B1 patent drawingFigure 1
  • EP2718108B1 patent drawingFigure 2
  • EP2718108B1 patent drawingFigure 3

AI summary

The invention relates to a method for printing workpieces (4) comprising the following steps: feeding a workpiece (4) to at least one workpiece carrier (7); fixing the workpiece (4) to the workpiece carrier (7); delivering the workpiece (4) on the workpiece carrier (7) to a printer (14); measuring the delivery speed of the workpiece (4) on the workpiece carrier (7); and controlling the printing speed as a function of the measured delivery speed. As a result, it is possible to compensate for fluctuations in the actual delivery speed of the workpiece.