Sheet Folding Apparatus Movable Roller Cover

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Solution Overview

Problem

Existing sheet folding apparatuses face issues with abrasion and reduced elemental force due to the tilt angle of springs, leading to inconsistent folding and increased resistance, while post-processing trays cause wrinkles due to varying pressure with sheet thickness.

Innovation Solution

A sheet folding apparatus with a stacker, first and second folding rollers, a blade unit, and a movable roller cover that prevents the second folding roller from contacting the sheets, allowing for precise folding and maintaining consistent pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a spring is used to bias the folding roller, then the folding roller can be separated from the first folding roller, but the tilt angle of the spring causes reduction of elemental force and inconsistent folding

Engineering Contradiction:

Improveseparable folding rollerVSAvoidfolding position consistency

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent makes the second folding roller movable rather than fixed, allowing it to dynamically adjust its position relative to the first folding roller. The roller can be separated when not in use and automatically positions itself during operation, combining adaptability with precision through dynamic movement controlled by the blade unit and spring mechanism.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The spring mechanism automatically biases the second folding roller into the correct position against the first folding roller when the blade unit advances the sheet bundle. The system self-regulates the folding pressure and position without requiring external control, eliminating the need for complex adjustment mechanisms while maintaining consistent folding.

Inventive Principle:

Principle #25Self-service

2Reliability

If a strong spring is employed to avoid abrasion, then the pivot abrasion is reduced, but resistance force against advancing the stick-out plate increases

Engineering Contradiction:

Improvepivot abrasion resistanceVSAvoidresistance force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The patent removes the pivot point from the spring mechanism entirely. Instead of using a spring that rotates on a pivot, the design uses a spring that directly biases the second folding roller along a linear path. This eliminates the pivot abrasion problem while maintaining reliable operation without requiring excessive spring force.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the traditional spring-pivot-mechanism with a blade unit that directly advances the sheet bundle into the nip between the folding rollers. This substitution eliminates the need for the spring to tilt and pivot, removing the source of abrasion while reducing resistance force through more efficient mechanical action.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If the post processing tray is fixed, then the structure is simple, but the nip varies relative position against the tray causing wrinkles

Engineering Contradiction:

Improvetray structureVSAvoidfold position accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent makes the second folding roller dynamic rather than fixing the tray. The roller can move independently to maintain the correct nip position against the sheet bundle, accommodating variations in sheet thickness without requiring a complex adjustable tray structure. This dynamic roller approach preserves structural simplicity while ensuring fold position accuracy.

Inventive Principle:

Principle #15Dynamics

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 ensures precise and consistent folding without abrasion or wrinkles, reducing resistance and maintaining accurate folding across varying sheet thicknesses.

Implementation Method 1

a second folding roller configured to rotate around a second axis which is in parallel with the first axis and biased to the first folding roller separably to make a nip together with the first folding roller therebetween

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 2

a blade unit configured to push the plurality of sheets stacked by the stacker into the nip

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 3

a movable roller cover configured to move together with the second folding roller in the separating direction to prevent the second folding roller from contacting the plurality of sheets stacked by the stacker when the blade unit starts contacting the plurality of sheets stacked by the stacker

Methodology Applied

Scientific EffectMechanical Movement: Displacement

Data Source

PatentUS7892161B2Sheet folding apparatus, sheet folding unit and image forming apparatus

Publication Date: 2011.02.22 KK TOSHIBA

AI summary

A sheet folding unit, including: a first folding roller configured to rotate around a first axis; a second folding roller configured to rotate around a second axis which is in parallel with the first axis and biased to the first folding roller separably to a separating direction to make a nip together with the first folding roller therebetween; a blade configured to push a surface of a sheet into the nip; and a roller cover configured to move together with the second folding roller in the separating direction to prevent the second folding roller contacting the sheet when the blade unit starts contacting the sheet.