Sheet Discharging Device Pressing Mechanism

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Solution Overview

Problem

Existing image forming apparatuses face issues with sheet discharge, where a sheet holder may not effectively shift a curled sheet, leading to improper loading or discharging, and can cause damage to limp sheets by not moving upward, resulting in wrinkles.

Innovation Solution

A sheet discharging device with a pressing mechanism comprising a first and second pressing member, where the first member provides a small pressing force to prevent buckling and the second member applies a larger force to suppress curling, allowing for effective discharge and loading of sheets regardless of their rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the weight of the sheet holder is increased to shift curled sheets downward, then rigid curled sheets can be effectively pressed, but limp sheets may be damaged or buckled due to excessive pressing force

Engineering Contradiction:

Improveeffectiveness in shifting curled sheetsVSAvoiddamage to limp sheets

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sheet holder is designed to dynamically adjust its pressing force based on the rigidity of the sheet. The holder can move upward upon contact with the sheet, and the control unit adjusts the pressing force magnitude according to sheet characteristics, enabling effective handling of both rigid curled sheets and limp sheets without damage

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control unit changes the pressing force parameter based on detected sheet conditions. When a sheet is detected, the control unit activates the sheet holder to press the sheet with an adjusted force level that prevents damage to limp sheets while effectively suppressing curls in rigid sheets

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If the weight of the sheet holder is decreased to avoid damaging limp sheets, then limp sheets can be discharged safely, but rigid curled sheets cannot be sufficiently shifted downward

Engineering Contradiction:

Improvedamage to limp sheetsVSAvoideffectiveness in shifting curled sheets

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention replaces the traditional gravity-based mechanical sheet holder with an actively controlled pressing mechanism. The sheet holder is driven by a drive unit that can precisely control the pressing force, substituting passive gravitational force with active mechanical control to achieve both gentle handling of limp sheets and effective pressing of rigid curled sheets

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The control unit dynamically adjusts the pressing force parameter based on sheet rigidity detection. This parameter adjustment enables the same sheet holder to exert sufficient force on rigid curled sheets while applying minimal force to limp sheets, resolving the contradiction between effectiveness and damage prevention

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If a single sheet holder is used for all sheet types, then the device structure remains simple, but the sheet discharging performance varies poorly across different sheet rigidities

Engineering Contradiction:

Improvestructure of sheet holder systemVSAvoidperformance across different sheet types

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The sheet holder is designed as a universal pressing mechanism that can handle multiple sheet types (rigid and limp) through active control. The control unit enables the same physical structure to adapt its pressing force to different sheet conditions, achieving multi-functionality without requiring multiple separate holders

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control unit implements feedback control by detecting sheet presence and characteristics, then adjusting the pressing force accordingly. This feedback mechanism enables the single sheet holder to optimize its performance for each sheet type, achieving high adaptability while maintaining structural simplicity

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS8958740B2Configuration for a sheet discharging device

Publication Date: 2015.02.17 BROTHER KOGYO KK

AI summary

An apparatus configured to discharge sheets may include pressing mechanism configured to downwardly press discharged sheets. For example, the pressing mechanism may include a first pressing member and a second pressing member. The first pressing member and the second pressing member may be located at least partially overlapping positions in the width-wise direction of the sheet. Additionally or alternatively, each of the first pressing member and the second pressing member may be configured to contact the sheet at different positions along a discharge direction. In one example, the different portions may be spaced apart from each other in the discharge direction.