Sheet Conveyor Lifting Element Prevents Wrinkling

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Solution Overview

Problem

Inkjet printing processes often result in sheet curling and wrinkling due to moisture absorption, leading to permanent deformation, especially when sheets are transported on conventional conveyors without effective guidance mechanisms.

Innovation Solution

A sheet conveyor system featuring a supplying conveyor, a receiving conveyor, and a sheet guidance unit with a lifting element that lifts side edge portions of the sheet, allowing the middle portion to land on the receiving conveyor's support surface first, thereby preventing wrinkles by controlling the sheet's landing and attraction process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the sheet is transported directly onto the support surface of the receiving conveyor, then the transport process is simple and fast, but the sheet becomes wrinkled and permanently deformed

Engineering Contradiction:
Improvesheet flatnessVSAvoidconveyor structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The sheet conveyor system is divided into multiple independent conveyor units (first conveyor, second conveyor, third conveyor) that operate separately to perform different functions: transport, lifting, and receiving. This segmentation allows each unit to be optimized for its specific task while working together to prevent sheet wrinkling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lifting conveyor performs a preliminary action by lifting the side edge portions of the sheet before the sheet reaches the receiving conveyor. This preliminary lifting action creates an upward curve that prevents the sheet from landing flat and wrinkling on the receiving conveyor surface.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If suction force is applied to attract the sheet to the support surface, then the sheet is securely held during transport, but wrinkles are fixed permanently in the sheet

Engineering Contradiction:
Improvesheet holding stabilityVSAvoidsheet flatness
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The sheet is lifted into an upwardly curved shape before reaching the receiving conveyor, so that when suction is applied, the sheet is attracted in a curved state rather than a flat state. This preliminary curvature prevents wrinkles from forming or being fixed during the suction process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sheet's physical state is changed from flat to upwardly curved by the lifting conveyor. This parameter change in the sheet's shape allows the suction force to act on a curved surface, preventing the formation of permanent wrinkles while still providing secure holding.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the sheet is allowed to land flat on the receiving conveyor, then the transport process is efficient, but environmental humidity causes curling and wrinkling

Engineering Contradiction:
Improvetransport efficiencyVSAvoidsheet flatness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The lifting conveyor performs a preliminary action to counteract the curling effect of humidity by creating an upward curve in the sheet before it lands on the receiving conveyor. This preliminary shaping prevents the sheet from landing flat and developing wrinkles, maintaining both efficiency and flatness.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The lifting conveyor applies a preliminary anti-action by lifting the sheet edges upward to counterbalance the downward curling force caused by humidity absorption. This creates a pre-curved shape that resists the natural tendency to wrinkle when landing on the receiving conveyor.

Inventive Principle:
Principle #9Preliminary anti-action

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 solution effectively reduces or prevents wrinkling during sheet transport, ensuring that the sheet remains flat and minimizes deformation, even after drying, by guiding the sheet into an upwards curved shape and ensuring the middle portion lands on the support surface before the side edges, thus maintaining the sheet's integrity.

Implementation Method 1

The supplying conveyor may have a suction mechanism arranged for providing a suction force to attract a contact side of the sheet towards the transport belt

Methodology Applied
Scientific EffectSuction: Suction

Implementation Method 2

The receiving conveyor may further comprise a suction mechanism arranged for providing a suction force to attract the contact side of the sheet towards the support surface of the transport belt of the receiving conveyor

Methodology Applied
Scientific EffectSuction: Suction

Data Source

PatentEP3274282B1Sheet conveyor for transporting a sheet, method for transporting a sheet in a sheet conveyor, inkjet printing apparatus comprising the sheet conveyor
Publication Date: 2021.07.14 CANON PRODUCTION PRINTING NETHERLANDS BV
  • EP3274282B1 patent drawingFigure 1
  • EP3274282B1 patent drawingFigure 2A~2B
  • EP3274282B1 patent drawingFigure 2C~4

AI summary

A sheet conveyor is provided for transporting a sheet (20). The sheet conveyor comprises a supplying conveyor (10), a receiving conveyor (40) and a sheet guidance unit (100). The receiving conveyor comprises a support surface (42) arranged for supporting the sheet on a contact side (21) of the sheet and an attraction unit (46) arranged for attracting the sheet to the support surface. The supplying conveyor comprises a transport belt (14) being arranged for advancing the sheet in a transport direction along a transport path towards the support surface of the receiving conveyor; the sheet having two side edge portions (26) relative to the transport path. The sheet guidance unit is arranged at a downstream end of the transport path for guiding the sheet towards the receiving conveyor, wherein said sheet guidance unit comprises a lifting element (130a, 130b) arranged for lifting both side edge portions of the sheet away from the support surface while a middle portion of the sheet in between both side edge portions is guided towards the support surface.