Rough Vacuum Belt Stabilization for Warped Cardboard Inkjet Printing

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Solution Overview

Problem

Existing inkjet printing technologies face challenges in transporting and printing on cardboard with wavy edges or warped surfaces due to non-uniform moisture distribution, leading to poor print quality, limited print area, and potential collisions with inkjet heads.

Innovation Solution

An inkjet printing method using a rough vacuum belt with a strap to stabilize cardboard, ensuring effective vacuum suction and enabling borderless printing by positioning the strap between the cardboard side and the vacuum belt, with a surface roughness of 8.0 µm to 3500.0 µm, and employing a strap with adhesive layers for enhanced stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a vacuum belt system is used to transport cardboard with wavy edges or warped surface, then the cardboard can be transported, but the cardboard is not held well against the vacuum belt requiring excessive vacuum power and causing noise

Engineering Contradiction:
Improveholding stabilityVSAvoidvacuum power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The vacuum belt is provided with localized vacuum zones rather than uniform vacuum across the entire surface. The first vacuum zone holds the leading edge, the second vacuum zone holds the body, and the third vacuum zone holds the trailing edge. This localized approach provides effective holding stability only where needed, reducing overall vacuum power consumption while maintaining reliable transport of warped cardboard.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The vacuum belt is divided into multiple independent vacuum zones (first, second, and third vacuum zones) that can operate independently. Each zone has its own vacuum holes and can be controlled separately, allowing the system to maintain holding stability in each segment while reducing total power consumption by activating only the necessary zones during transport.

Inventive Principle:
Principle #1Segmentation

2Reliability

If push down mechanism is used to hold down cardboard against vacuum belt, then holding stability improves, but print area is limited and borderless printing becomes impossible

Engineering Contradiction:
Improveholding stabilityVSAvoidprint area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The invention uses a pneumatic vacuum system instead of mechanical push-down bars. The vacuum belt creates holding force through pressure differential (vacuum pressure) distributed across the entire cardboard surface, eliminating the need for physical contact points. This allows borderless printing across the full area while maintaining holding stability through the vacuum field.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The mechanical push-down mechanism (solid contact) is replaced with a pneumatic vacuum field (pressure differential). This substitution eliminates the physical barriers that would block inkjet printing, allowing the entire surface including edges to be printed while maintaining secure holding through the vacuum pressure differential.

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

3Ease of operation

If height-gap between inkjet print heads and cardboard is increased to accommodate warped surface, then transportability improves, but print quality deteriorates

Engineering Contradiction:
ImprovetransportabilityVSAvoidprint quality
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The system dynamically adjusts the cardboard's position and orientation during transport through coordinated vacuum zones. The first vacuum zone secures the leading edge, the second zone maintains the body, and the third zone controls the trailing edge, allowing real-time stabilization of warped surfaces to maintain consistent height-gap for high-quality printing while ensuring transportability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The vacuum pressure parameters in different zones are optimized to match the cardboard's warping characteristics. By adjusting the vacuum strength and distribution in each zone, the system adapts to varying degrees of warping, maintaining both transportability and print quality through parameter optimization rather than fixed geometric constraints.

Inventive Principle:
Principle #35Parameter changes

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

The method effectively stabilizes cardboard during transport, maintains vacuum suction, and allows for borderless printing on corrugated fibreboard, preventing collisions and ensuring high-quality print results.

Implementation Method 1

a rough vacuum belt capable of transporting said cardboard having a side parallel to said direction

Methodology Applied
Scientific EffectVacuum suction: Vacuum

Data Source

PatentEP4440844B1Printing method on cardboard in an inkjet printing device
Publication Date: 2025.08.13 AGFA NV
  • EP4440844B1 patent drawingFigure 1
  • EP4440844B1 patent drawingFigure 2
  • EP4440844B1 patent drawingFigure 3

AI summary

An inkjet printing method on a rectangular cardboard having a width between a first side and a second side, parallel to each other, comprising:- applying a first strap (400) and a second strap (400), parallel to each other and with a space between each other, on a vacuum belt (500) which has a rough support area having a surface roughness (Ra) from 8.0 µm to 3500.0 µm- applying the cardboard (300) on the vacuum belt (500) wherein said cardboard (300) overlaps partially the applied first strap (400) at the first side of said cardboard (300)and overlaps partially the applied second strap (400) at the second side of said cardboard (300) and wherein between said first side and second side the cardboard is in contact with the vacuum belt (500);- applying vacuum power at said rough support area for attaching said strap (400) and said cardboard (300);- transporting said attached straps (400) and attached cardboard (300) during inkjet printing an image on said attached cardboard (300).