Sheet Discharge Guide Restricting Rear End Upward Movement

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Solution Overview

Problem

In image forming apparatuses, such as printers and copiers, sheets of recording medium often collide upon discharge due to the rear end of one sheet obstructing the passage, leading to unsatisfactory stacking in the delivery tray.

Innovation Solution

A sheet discharging apparatus with a nip portion, a supporting portion, and a guide portion featuring a fixed restricting portion that prevents the rear end of a sheet from moving upward after passing through the nip, ensuring proper alignment and stacking by restricting the sheet's movement away from the discharge direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If sheets are discharged in succession through the nip portion, then productivity is improved, but the rear end of the preceding sheet blocks the sheet passage causing the front of the next sheet to collide with it

Engineering Contradiction:

Improvesheet discharge speedVSAvoidsheet stacking quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The fixed restricting portion is positioned to preliminarily prevent the rear end of the sheet from moving upward before the sheet is fully discharged. By restricting the rear end position in advance during the discharge process, the invention prevents collision with the next sheet while maintaining high discharge speed

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The fixed restricting portion acts as an intermediary element between the discharged sheet and the sheet passage. It mediates the position of the rear end of the sheet, preventing it from blocking the passage while allowing the sheet to be discharged smoothly at high speed

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the rear end of the sheet moves upward after passing through the nip portion, then the sheet can be discharged completely, but it blocks the sheet passage and causes collision with the next sheet

Engineering Contradiction:

Improvesheet discharge completenessVSAvoidsheet collision

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The fixed restricting portion applies preliminary anti-action by preventing the rear end of the sheet from moving upward in the first place. This counteracts the natural tendency of the sheet rear end to rise after passing through the nip, thereby preventing the harmful effect of blocking the sheet passage and causing collision

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS11514281B2Sheet discharging apparatus and image forming apparatus

Publication Date: 2022.11.29 CANON KK

AI summary

A sheet discharging apparatus includes a sheet supporting portion supporting a sheet discharged out of a nip portion nipping the sheet and a guide portion provided opposed to an upper surface of the sheet fed out of the nip portion. The guide portion includes a fixed restricting portion restricting a rear end of the sheet with respect to a sheet discharging direction to moving upward away from an extension line in a sheet discharging direction of the nip portion after passing through the nip portion.