Sheet Conveyance Skew Correction with Rotating Width Guides

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Solution Overview

Problem

Conventional sheet conveyance devices face challenges in improving conveyance speed without causing an increase in size or conveyance failures due to skew correction mechanisms that require large spaces or risk sheet distortion.

Innovation Solution

A skew correction unit that includes a guide member supporting the sheet along its width direction, rotating about an axis parallel to the conveyance direction to correct skew feeding by displacing guide members and adjusting the conveyance path length based on detected skew amounts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a register roller is used to correct skew feeding by repeating rotation and stop cycles, then skew feeding can be corrected, but the operation speed is limited due to rotational inertia causing timing deviation

Engineering Contradiction:

Improveskew feeding correction accuracyVSAvoidoperation speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The skew correction rollers are positioned upstream before the main conveyance path, performing skew correction in advance. This allows the sheet to be fed at a constant speed without repeated stopping, eliminating the speed limitation caused by rotational inertia of traditional register rollers.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The skew correction function is separated from the main conveyance function. Dedicated skew correction rollers handle only the skew correction task independently, allowing continuous operation at constant speed while maintaining correction accuracy.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If conveyance rollers are arranged at different positions in the conveyance direction to correct skew, then skew feeding can be corrected, but the device size increases in the conveyance direction

Engineering Contradiction:

Improveskew feeding correction accuracyVSAvoiddevice size in conveyance direction

Core Design Contradiction:

Manufacturing precisionVSLength of stationary object

Solution Approach 1:

The skew correction mechanism operates in the width direction rather than extending the conveyance direction. By arranging correction rollers side-by-side across the sheet width and controlling their differential rotation, skew correction is achieved without increasing the device length in the conveyance direction.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If different rotation speeds are given to conveyance rollers to correct skew, then skew feeding can be corrected, but sheet distortion may occur due to speed differences

Engineering Contradiction:

Improveskew feeding correction accuracyVSAvoidsheet flatness

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

Different linear speeds are applied only to specific local regions of the sheet (where skew exists) while maintaining uniform speed in other regions. This localized speed differentiation corrects skew without causing overall sheet distortion or wrinkling.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250289677A1Sheet conveyance device

Publication Date: 2025.09.18 RISO KAGAKU CORP

AI summary

A sheet conveyance device comprises: a skew detector that detects a skewed amount with respect to a conveyance direction of a sheet to be conveyed; and a skew corrector that corrects skew feeding of the sheet, and the skew corrector includes a guide member that supports the sheet along a width direction, and displaces the guide member so as to rotate a region in the width direction of the sheet supported by the guide member about an axis parallel to a conveyance direction according to a skewed amount of the sheet.