Image Control Device for Web Width Compensation

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Solution Overview

Problem

Web-fed printing presses face issues with width changes, particularly with elastic substrates like plastic films, where the firm clamping by cylinder groups causes stretching and subsequent width reduction, leading to registration deviations between process colors.

Innovation Solution

A web-fed printing press equipped with an image control device, comprising mechanical image controllers or air nozzles, is arranged in front of the cylinder group of the first printing unit to reduce the web width before printing, allowing for real-time adaptation to substrate-specific stretching and constriction, ensuring consistent registration across multiple printing units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the printing material web is firmly clamped by cylinder groups for printing, then the printing process is stable and efficient, but the web stretches in the longitudinal direction and width is reduced, causing registration deviations

Engineering Contradiction:

Improveprinting efficiencyVSAvoidregistration accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The image control device is positioned before the first printing unit to preemptively reduce the web width, counteracting the stretching effect that will occur during subsequent printing operations. This preliminary action prevents registration deviations before they happen, allowing stable and efficient printing without compromising precision.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The web width reduction is performed in advance before the printing process begins. By pre-adjusting the web dimensions using the image control device, the system ensures that the web is properly conditioned for printing, eliminating the need for post-printing corrections and maintaining both efficiency and accuracy.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If image regulators are arranged after the first printing unit to compensate for width increase, then the fan-out effect is corrected for moisture-absorbing materials, but this solution does not work for elastic substrates that stretch under tension

Engineering Contradiction:

Improveprint image registrationVSAvoidcompatibility with different substrate types

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

Instead of arranging image control devices after the printing unit to compensate for width changes, the invention inverts the approach by positioning them before the first printing unit. This allows the web width to be reduced preemptively, making the solution effective for elastic substrates that stretch during printing, rather than just for moisture-absorbing materials.

Inventive Principle:

Principle #13The other way round (Inversion)

3Manufacturing precision

If the web width is reduced by image control device before the first printing unit, then registration accuracy is maintained across all printing units, but additional equipment is required in the printing press

Engineering Contradiction:

Improvecolor registration consistencyVSAvoidprinting press structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The image control device acts as an intermediary component between the web feed and the printing units. It mediates the web width adjustment without interfering with the core printing mechanism, adding minimal complexity while achieving the goal of consistent color registration across all printing units.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enables direct compensation for width changes, preventing registration deviations between process colors and maintaining consistent print image width across all printing units, thereby ensuring accurate color registration without the need for preliminary scaling.

Implementation Method 1

with such elastic substrates such as plastic films, this firm clamping of the printing material web within the printing units means that the printing material after the cylinder group, viewed in the direction of web travel, is stretched or stretched in the longitudinal direction

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP3683060B1Device and method for print width adjustment

Publication Date: 2021.09.29 MANROLAND GOSS WEB SYST GMBH

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Figure 5~6

AI summary

A rotary printing press (1) and a method for compensating for print width. The invention is based on the objective of providing a solution for compensating for changes in the width of the first printed image applied by the first printing unit (4-1) as viewed in the web direction LR. The device according to the invention comprises a rotary printing press (1) in which the at least one image control device (6) is arranged upstream of the cylinder group (5) of the first printing unit (4-1) as viewed in the web direction LR. The method according to the invention relates to a method for operating a rotary printing press (1) in which the reduction of the web width B to an effective width b as viewed in the web direction LR is carried out upstream of the cylinder group (5) of the first printing unit (4-1) as viewed in the web direction LR.