Angled Sheet Stacker Prevents Double Feeding

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Solution Overview

Problem

Existing sheet feeders in image forming apparatuses face challenges with double feeding due to burrs at the trailing ends of lamination sheets, which are not effectively managed by current tray configurations.

Innovation Solution

The sheet feeder incorporates a sheet stacker with a first and second stacking face forming a specified angle, integrated with a lifter to maintain a consistent pressing force on the sheets, thereby preventing excessive drooping and burr-related double feeding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional flat feed tray is used to stack sheets, then the device complexity is low, but the sheets experience excessive drooping and burr-related double feeding

Engineering Contradiction:

Improvesheet feeding reliabilityVSAvoidstacker structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The feed tray is segmented into multiple stacking faces (first stacking face and second stacking face) with different orientations. The first stacking face is inclined at a first angle relative to the horizontal direction, while the second stacking face is inclined at a second angle different from the first angle. This segmentation allows each face to perform specialized functions: the first face prevents drooping by utilizing gravity, while the second face prevents double feeding by creating clearance between sheets.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the stacker have different local qualities through the varied inclination angles of the stacking faces. The first stacking face has a steeper inclination to effectively utilize gravity for preventing drooping, while the second stacking face has a shallower inclination to create appropriate clearance for preventing double feeding. This local differentiation optimizes the overall sheet feeding reliability.

Inventive Principle:

Principle #3Local quality

2Reliability

If the stacker structure is simplified, then the manufacturing cost is reduced, but the ability to prevent double feeding and non-feeding deteriorates

Engineering Contradiction:

Improveprevention of double feeding and non-feedingVSAvoidstacker manufacturing ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The stacker is divided into multiple stacking faces with different inclination angles, allowing each face to address specific feeding issues. This segmentation enables the prevention of both double feeding and non-feeding through functional differentiation without requiring complex mechanical mechanisms.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the geometric parameters (inclination angles) of the stacking faces to optimize sheet feeding. By adjusting the first angle and second angle of the stacking faces, the system achieves effective prevention of drooping and double feeding while maintaining a relatively simple overall structure that is ease of manufacture.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a single stacking face is used, then the device complexity is minimized, but the sheet alignment and clearance maintenance are insufficient

Engineering Contradiction:

Improvesheet alignment and clearanceVSAvoidstacking face configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The single stacking face is segmented into multiple faces with different inclination angles. The first stacking face maintains sheet alignment through its specific angle, while the second stacking face maintains clearance between sheets through its different angle. This segmentation achieves better alignment and clearance maintenance without requiring complex mechanical adjustment mechanisms.

Inventive Principle:

Principle #1Segmentation

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 configuration reduces the occurrence of double feeding and non-feeding by maintaining clearances between sheets and ensuring consistent sheet alignment, improving the reliability of the sheet feeding process.

Implementation Method 1

a bent portion integrally connecting the first stacking face and the second stacking face such that the first stacking face and the second stacking face form a specified angle

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The lifter lifts and lowers the sheet stacker depending on a stack amount of the sheets

Methodology Applied

Scientific EffectMechanical force: Mechanical Force

Implementation Method 3

The sheet stacker stacks the sheets such that a center of gravity of the sheets is positioned above the first stacking face

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS12338089B2Sheet feeder, laminator, image forming apparatus, and image forming system

Publication Date: 2025.06.24 RICOH CO LTD

AI summary

A sheet feeder includes a sheet stacker, a sheet feed roller, a separation roller pair, and a lifter. Sheets are conveyed and stacked on the sheet stacker. The sheet feed roller feeds the sheets. The separation roller pair separates the sheets fed by the sheet feed roller one by one. The lifter lifts and lowers the sheet stacker depending on a stack amount of the sheets. The sheet stacker includes a first stacking face, a second stacking face, and a bent portion integrally connecting the stacking faces such that the stacking faces form a specified angle. The sheet stacker stacks the sheets such that a center of gravity of the sheets is positioned above the first stacking face and integrally displaces the stacking faces when the lifter operates.