Sheet Ejecting Roller Pair Alignment Control

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Solution Overview

Problem

Existing sheet conveying devices face issues with defective alignment of ejected sheets due to the reverse conveying path, leading to misalignment and operational inefficiencies during duplex printing.

Innovation Solution

The automatic document conveying device employs a control mechanism that coordinates the rotation of the sheet ejecting roller pair and reverse roller pair, using a clutch and actuator to manage the sheet's alignment and ejection, ensuring proper positioning without the need for additional trays, thereby preventing misalignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a reverse conveying path is used to reverse sheets for duplex printing, then productivity is improved by enabling double-sided reading, but sheet alignment deteriorates causing defective alignment of ejected sheets

Engineering Contradiction:
ImproveproductivityVSAvoidsheet alignment
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The sheet ejecting roller pair temporarily holds the sheet at a predetermined position (nipping state) before final ejection to the ejecting tray. This preliminary positioning action ensures that subsequent sheets can be properly aligned without causing defective alignment, while still enabling efficient duplex printing operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sheet ejecting roller pair acts as an intermediary mechanism between the reverse conveying path and the ejecting tray. It temporarily retains sheets in a controlled nipping state, mediating the transition from reverse conveyance to final ejection, thereby preventing alignment defects caused by direct ejection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If sheets are temporarily held in the ejecting space above the ejecting tray, then sheet alignment is improved, but device complexity increases requiring additional trays or structures

Engineering Contradiction:
Improvesheet alignmentVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The sheet ejecting roller pair performs multiple functions: it ejects sheets to the tray, temporarily holds sheets in a nipping state for alignment, and prevents sagging of subsequent sheets. By making this existing component multi-functional, the invention achieves improved alignment without adding separate trays or complex structures.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The sheet ejecting roller pair uses its own nipping function to achieve sheet alignment and positioning. The roller pair serves itself by utilizing its inherent gripping capability to temporarily hold sheets, eliminating the need for separate alignment mechanisms or additional trays.

Inventive Principle:
Principle #25Self-service

3Speed

If the sheet ejecting roller pair rotates continuously, then ejection speed is improved, but sheet alignment deteriorates causing defective alignment

Engineering Contradiction:
Improveejection speedVSAvoidsheet alignment
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The sheet ejecting roller pair operates periodically rather than continuously - rotating to eject a sheet, then stopping to hold the next sheet in a nipping state. This periodic operation rhythm maintains ejection speed while ensuring proper alignment by pausing at critical moments to position sheets correctly.

Inventive Principle:
Principle #19Periodic action

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

This solution stabilizes the alignment of sheets in the ejecting tray, enhances operational efficiency, and reduces costs by eliminating the requirement for additional trays, while maintaining good sheet takeability and preventing sagging issues.

Implementation Method 1

a sheet ejecting roller pair 328 for ejecting the document sheet P to the document ejecting tray 31; a reverse roller pair 329 for conveying the document sheet P in the switchback manner

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3079021B1Sheet conveying device and image forming apparatus having the same
Publication Date: 2023.08.23 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

A sheet conveying device (3) includes a first tray (30), a conveying portion (32), a second tray (31), and a conveyance control portion (50). The conveying portion (32) has: a first conveying path (32A) that extends from the first tray (30); a second conveying path (32B) that makes the first conveying path (32A) and the second tray (31) communicate with each other and is provided with an ejecting roller pair (328); a third conveying path (32C) that makes the second conveying path (32B) and an ejecting space (3S) communicate with each other and is provided with a reverse roller pair (329). After a first sheet (P1) passes through a reference position (X), the conveyance control portion (50) stops rotation of the ejecting roller pair (328) with the first sheet (P1) conveyed in the second conveying path (32B) nipped by the sheet ejecting roller pair (328), and after a second sheet (P2) passes through the reference positon (X), the conveyance control portion (50) rotates the reverse roller pair (329) with the rotation of the ejecting roller pair (328) stopped.