Sheet Decurling Device with Movable Roller for Variable Nipping Force
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Solution Overview
Problem
Roller type sheet decurling devices face challenges in maintaining a large nip width, leading to issues with sheet conveyance failure due to inadequate nipping force when the belt tension is reduced and increased traveling load when tension is increased, affecting the decurling efficiency and speed.
Innovation Solution
A sheet decurling device with a nip forming part that includes multiple rollers with different outer curvatures and a change-over mechanism, allowing selective pressure contact with a belt to adjust the decurling force based on sheet basis weight, ensuring consistent nipping pressure and conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the amount of belt wrapped around the hard roller is increased to increase decurling force, then the decurling force increases, but the traveling load of the belt increases and sheet conveyance speed decreases
Solution Approach 1:
The patent applies dynamics by making the decurling roller movable rather than fixed. The decurling roller can be positioned at different locations along the belt's path, allowing the system to dynamically adjust the decurling force applied to the sheet. This movable configuration enables optimization between decurling force and conveyance speed without being constrained by a fixed belt wrap amount
Solution Approach 2:
The patent changes the parameter of decurling roller position to control decurling force. By adjusting where the decurling roller contacts the belt along its path, the system varies the effective decurling force without changing the total belt wrap amount, thus avoiding increased traveling load while maintaining adequate decurling capability
2Productivity
If the amount of belt wrapped around the hard roller is decreased to reduce traveling load, then the traveling load decreases, but the sheet nipping force drops and sheet conveyance failure occurs
Solution Approach 1:
The patent applies local quality by concentrating the decurling function at a specific localized position where the decurling roller contacts the belt. Rather than relying on distributed friction along a long belt wrap, the system creates a focused decurling zone with the movable roller, ensuring adequate nipping force at the critical location without requiring excessive total belt wrap
Solution Approach 2:
The movable decurling roller allows the system to dynamically position the nipping force where needed. This dynamic positioning ensures reliable sheet conveyance by placing the decurling action at the optimal location, maintaining conveyance reliability without increasing overall belt tension or traveling load
3Device complexity
If a fixed belt wrap configuration is used, then the device structure is simple, but it cannot adequately handle sheets with different basis weights
Solution Approach 1:
The patent introduces dynamics through the movable decurling roller that can be repositioned along the belt's path. This single dynamic element provides adaptability to handle sheets of different basis weights by adjusting the decurling force application point, avoiding the need for multiple fixed configurations or complex variable mechanisms
Solution Approach 2:
The movable decurling roller serves multiple functions: it provides decurling force, adjusts to different sheet weights, and maintains consistent performance across varying operating conditions. This single multi-functional component replaces what would otherwise require multiple specialized components for different sheet types, achieving versatility without proportionally increasing device complexity
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 allows for effective decurling of sheets with varying basis weights by adjusting the decurling force and maintaining consistent nipping pressure, preventing sheet conveyance failures and optimizing conveyance speed.
Implementation Method 1
a decurling roller pressing the first belt with a predetermined pressure
Data Source
AI summary
A sheet decurling device includes a decurling conveyance part and a nip forming part. The decurling conveyance part includes a plurality of first rollers provided axially rotatably and a first belt wrapped around the first rollers. The nip forming part forms a nip part nipping and conveying a sheet with the first belt. The nip forming part includes a plurality of decurling rollers whose curvatures of outer circumferential surfaces are different from each other and a change-over mechanism. The change-over mechanism supports the plurality of de curling rollers axially rotatably and selectively changes over the decurling roller to be brought into pressure contact with the first belt.