Heating Conveyance Guide Alignment to Reduce Sheet Curl

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Solution Overview

Problem

Existing image forming apparatuses cause significant curling of sheets ejected from the ejection port due to the curved conveyance path, leading to poor appearance and stacking properties of the sheets.

Innovation Solution

A heating conveyance device with a fixing device and conveyance guide that inclines the conveyance direction of sheets relative to the vertical, using a fixing nip formed by a fixing rotator and pressure rotator, and a conveyance guide that corrects the curl by bending the sheets along a specific angle, reducing curl formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the conveyance path is curved to guide the sheet from the fixing nip to the ejection port, then the sheet can be conveyed to the ejection port, but the sheet becomes bent and develops large curl

Engineering Contradiction:
Improveconveyance guidanceVSAvoidsheet curl
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The conveyance guide is configured with a specific inclination angle relative to the vertical line passing through the fixing nip exit. This preliminary angular adjustment counteracts the curling tendency of the sheet by guiding it along a path that compensates for the expected deformation, thereby reducing the final curl when the sheet reaches the ejection port.

Inventive Principle:
Principle #9Preliminary anti-action

2Device complexity

If the conveyance guide is aligned vertically with the fixing nip exit, then the conveyance path is straightforward, but the sheet develops large curl and poor stacking properties

Engineering Contradiction:
Improveconveyance path alignmentVSAvoidsheet appearance
Core Design Contradiction:
Device complexityVSShape

Solution Approach 1:

The conveyance guide is deliberately positioned asymmetrically with respect to the vertical line passing through the fixing nip exit. Instead of symmetric vertical alignment, the guide is inclined at a specific angle to one side, creating an asymmetric conveyance path that effectively reduces sheet curl and improves stacking properties.

Inventive Principle:
Principle #4Asymmetry

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 sheet curling, enhancing the appearance and stacking quality of ejected sheets by correcting the curl through controlled conveyance and guide alignment.

Implementation Method 1

The heater heats the fixing rotator and extends in a width direction

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP4641312A1Heating conveyance device and image forming apparatus
Publication Date: 2025.10.29 RICOH CO LTD
  • EP4641312A1 patent drawingFigure 1
  • EP4641312A1 patent drawingFigure 2~4
  • EP4641312A1 patent drawingFigure 5A~6

AI summary

A heating conveyance device (19) includes a fixing device (20) and a conveyance guide (110, 130). The fixing device (20) includes a fixing rotator (21, 22), a heater (24, 35, 50), and a pressure rotator (31) pressed against the fixing rotator (21, 22) to form a fixing nip through which a sheet (P) is conveyed in a conveyance direction. The conveyance guide (110, 130) guides the sheet (P) fed from the fixing nip to an ejection port (A, B). In a cross section orthogonal to the width direction, the fixing device (20) ejects the sheet (P) from an exit (N2) of the fixing nip to the conveyance guide in the conveyance direction (S) inclined concerning a vertical line (H) passing through the exit (N2). The ejection port (A, B) is disposed at one side of the virtual vertical line (H), and the conveyance direction (S) is inclined toward another side.