Movable Ejection Tray for Sheet Stacking and Ejection

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Solution Overview

Problem

Existing post-processing apparatuses face challenges in efficiently stacking a large number of sheet bundles after saddle stitching, as inclined sheet ejection trays are not suitable for stacking multiple bundles without causing buckling or deformation, especially with low-stiffness papers.

Innovation Solution

A post-processing apparatus with a sheet ejection tray that includes a movable tray and distal end fence, capable of rotating between stacking and ejection positions, allowing for appropriate positioning and alignment of sheet bundles for either stacking or sequential ejection, using sensors and controllers to manage the tray's position and ensure proper alignment and ejection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the sheet ejection tray is constantly inclined to enable continuous ejection of sheet bundles, then productivity is improved, but the ability to stack a large number of sheet bundles deteriorates

Engineering Contradiction:
Improvecontinuous ejection capabilityVSAvoidstacking capacity
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The sheet ejection tray is designed to dynamically change its inclination angle between a first angle (for stacking) and a second angle (for ejection). The tray rotates around a rotation axis to switch between these angles, allowing the system to adapt its configuration based on whether stacking or ejection is the current operational requirement, thus resolving the contradiction between continuous ejection capability and stacking capacity.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the sheet ejection tray is constantly inclined to enable continuous ejection, then ease of operation is improved, but sheet deformation deteriorates

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidsheet bundle alignment
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The tray dynamically adjusts its inclination angle to match operational needs. When stacking sheet bundles, the tray adopts a first inclination angle that facilitates proper stacking. When ejection is required, it switches to a second inclination angle that enables continuous discharge. This dynamic adjustment prevents deformation and misalignment that would occur with a constantly inclined tray.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system proactively switches the tray to the appropriate inclination angle before performing stacking or ejection operations. By anticipating the operational requirement and pre-positioning the tray at the correct angle, the system prevents sheet bundle deformation and misalignment from occurring in the first place.

Inventive Principle:
Principle #9Preliminary anti-action

3Adaptability or versatility

If the sheet ejection tray is made movable and rotatable to enable both stacking and ejection, then adaptability is improved, but device complexity deteriorates

Engineering Contradiction:
Improvedual functionality for stacking and ejectionVSAvoidtray mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The tray mechanism uses a single rotation axis to enable the tray to pivot between two fixed inclination angles. This dynamic design allows one component to perform multiple functions (stacking and ejection) without requiring separate mechanisms for each function, thereby achieving versatility while limiting complexity growth.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sheet ejection tray serves multiple functions: it can stack sheet bundles at a first inclination angle and eject them at a second inclination angle. This multi-functional design eliminates the need for separate stacking and ejection mechanisms, achieving adaptability while keeping the overall device complexity manageable through component consolidation.

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

Data Source

PatentEP4095075B1Post-processing apparatus and image forming system incorporating the post-processing apparatus
Publication Date: 2024.05.15 RICOH CO LTD
  • EP4095075B1 patent drawingFigure 1
  • EP4095075B1 patent drawingFigure 2
  • EP4095075B1 patent drawingFigure 3A~3B

AI summary

A post-processing apparatus (3) includes a post-processing device (27, 28, 29), an ejection device (18, 19), and an ejection tray (30). The post-processing device (27, 28, 29) executes post-processing on a medium on which an image is formed by an image forming apparatus (2). The ejection device (18, 19) ejects the medium on which the post-processing is executed by the post-processing device (27, 28, 29). The ejection tray (30) holds the medium ejected by the ejection device (18, 19). The ejection tray (30) includes a main tray (31) having an upper face inclined downward in an ejection direction, and a movable tray (32) being rotatably supported by the main tray (31) between a stacking position at which the medium remains stacked on the upper face of the movable tray (32) and an ejection position at which the medium slides along the upper face of the main tray (31).