Conveying Guide Recess Design for Sheet Jam Prevention

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Solution Overview

Problem

Conventional sheet conveying apparatuses in image forming systems face issues with sheet jams and damage due to protrusions on the conveying surface, particularly from bend relief edges and bearing support structures, which increase part count and weight, hindering operability and workability.

Innovation Solution

A sheet conveying apparatus with a conveying guide formed from a plate, featuring a recessed surface and a bend portion that directs the sheet away from potential catch points, including bend relief edges, to prevent sheet jams and damage, while reducing the number of parts and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a bearing support portion is integrally formed by bending up from the conveying guide, then the structure is simplified, but bend relief edges project and cause sheet jams

Engineering Contradiction:
ImprovestructureVSAvoidsheet jam occurrence
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention extracts the problematic bend relief edges by creating a recess portion that removes these edges from the conveying surface. The bearing support portion is formed with a recess that eliminates the projecting edges caused by bending, thereby preventing sheet jams while maintaining the integral structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of having the bearing support portion protrude from the conveying surface, the invention inverts the approach by creating a recess portion that dips into the support structure. This inversion ensures that no edges project onto the conveying surface, solving the sheet jam problem.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If an additional member supporting the bearing is attached by welding or screwing, then sheet jams are avoided, but the number of parts and weight increase

Engineering Contradiction:
Improvesheet jam preventionVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the bearing support portion with the conveying guide by forming them as a single integral structure. The bearing support portion is created by bending up the conveying guide itself, eliminating the need for separate additional members while preventing sheet jams through the recess portion design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The conveying guide serves dual functions: it guides the sheet and provides structural support for the bearing through its own bent-up portion. This self-service approach eliminates the need for additional support members, reducing part count and weight while maintaining reliability.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If holes or slits are provided in the conveying guide, then conveying rollers can be projected, but projections may cause sheet jams

Engineering Contradiction:
Improveconveying roller projectionVSAvoidsheet jam occurrence
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention applies local quality by creating a recess portion specifically at the location where the bearing support portion is formed. This localized recess eliminates projecting edges only where they would interfere with sheet conveyance, while maintaining the necessary hole structure for roller projection in other areas.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2703323B1Sheet conveying apparatus and image forming apparatus
Publication Date: 2020.03.25 CANON KK
  • EP2703323B1 patent drawingFigure 1
  • EP2703323B1 patent drawingFigure 2
  • EP2703323B1 patent drawingFigure 3

AI summary

A conveying guide (200) comprising: a plate having a guide surface (47a) which guides a sheet; a recess portion (94a) provided on the plate and recessed from the guide surface; and a bend portion (92b) bent from the recess portion in a direction away from the guide surface.