Sheet Stacking Tray with Dual Conveyors and Pivotable Stopper

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Solution Overview

Problem

Existing sheet stacking systems face inefficiencies in forming and maintaining a stable, fully loaded bundle of folded sheets, as they lack effective mechanisms to manage the conveyance and stacking of sheets with varying thicknesses, leading to misalignment and reduced stacking efficiency.

Innovation Solution

A sheet stacking tray equipped with a first conveyor, a second conveyor, pivotable sheet stoppers, and detectors to form and maintain a sheet bundle by blocking and releasing sheets at optimal positions, ensuring proper alignment and full-load detection for efficient stacking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single conveyor is used to stack sheets, then the device complexity is low, but the stacking efficiency and alignment precision are insufficient

Engineering Contradiction:

Improvestacking efficiencyVSAvoidconveyor system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The conveyor system is divided into two separate conveyors: a first conveyor for conveying sheets to be stacked and a second conveyor for conveying already stacked sheets. This segmentation allows independent control of each conveyor, enabling the first conveyor to maintain high-speed sheet feeding while the second conveyor manages bundle formation and discharge, thereby resolving the contradiction between stacking efficiency and device complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sheet stopper is designed to be pivotable between a protruding position (to block sheets and form bundles) and a lowered position (to allow bundle discharge). This dynamic adjustment capability enables the system to adapt its blocking function based on real-time stacking status, improving stacking efficiency without requiring a permanently complex mechanical structure.

Inventive Principle:

Principle #15Dynamics

2Manufacturing precision

If sheets are continuously conveyed without blocking, then the conveying speed is high, but the sheet bundle alignment and bundle formation are poor

Engineering Contradiction:

Improvesheet bundle alignmentVSAvoidsheet conveyance speed

Core Design Contradiction:

Manufacturing precisionVSSpeed

Solution Approach 1:

The sheet stopper is positioned in advance at the upstream end of the stacking region to block sheets before they complete their conveyance. This preliminary blocking action allows sheets to be accumulated and aligned into proper bundles before discharge, ensuring manufacturing precision without requiring continuous high-speed operation throughout the entire conveyance path.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sheet stopper acts as an intermediary element between the first conveyor (sheet feed) and the second conveyor (bundle discharge). It mediates the sheet flow by selectively blocking and releasing sheets, enabling precise bundle formation while maintaining overall high conveyance speed through coordinated operation with both conveyors.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If the sheet stopper blocks sheets continuously, then the sheet bundle formation is good, but the stacking productivity decreases due to frequent stopping

Engineering Contradiction:

Improvebundle formation qualityVSAvoidstacking speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

While the sheet stopper periodically blocks sheets to form bundles, the second conveyor operates continuously to convey formed bundles away from the stacking region. This continuous action on the second conveyor prevents back-pressure accumulation and allows the first conveyor to maintain near-continuous operation, thereby preserving stacking productivity while achieving good bundle formation quality through the stopper's periodic blocking.

Inventive Principle:

Principle #20Continuity of useful action

4Measurement precision

If only one conveyor is used, then the device complexity is low, but the ability to detect full-load status and control sheet discharge timing is insufficient

Engineering Contradiction:

Improvefull-load detection accuracyVSAvoiddetector and control system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

A full-load detector is installed on the second conveyor to detect when the stacking tray reaches full capacity. This feedback signal is used by the controller to automatically adjust the sheet stopper's blocking behavior and coordinate the conveyors' operation, enabling precise full-load detection without requiring complex manual monitoring or overly complicated control mechanisms.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11498795B2Sheet stacking tray, sheet stacking apparatus, and image forming system

Publication Date: 2022.11.15 RICOH CO LTD

AI summary

A sheet stacking tray includes a first conveyor, a second conveyor, a sheet stopper, a first full-load detector, a second full-load detector, and a plurality of motors. The plurality of motors maintain the sheet stopper at a protruding position to block a sheet conveyed by the first conveyor until the first full-load detector outputs a signal indicating that a sheet bundle is fully loaded, shift the sheet stopper to a lowered position to allow the sheet bundle to pass when the first full-load detector outputs the signal indicating that the sheet bundle is fully loaded, drive the first conveyor and the second conveyor together to convey the sheet bundle when the sheet stopper shifts to the lowered position, and stop the second conveyor and drive only the first conveyor, when the second full-load detector detects a leading edge of the sheet bundle.