Sheet Stacking Conveyance Layout for Variable-Length Discharge

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Solution Overview

Problem

Conventional sheet conveyance devices have a complex structure due to the inclusion of a switchback conveyance path stacker and swing arm, leading to increased device size.

Innovation Solution

A compact sheet conveyance device design utilizing a stacking unit, carrying-in unit, discharge unit, lower and upper conveyance units, and a lifting and lowering unit with cam mechanisms to handle different sheet lengths efficiently, minimizing structural complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a switchback conveyance path stacker and swing arm are used to handle multiple sheet lengths, then the device can accommodate different sheet lengths, but the structure becomes complicated and the device size increases

Engineering Contradiction:
Improvecapability to handle different sheet lengthsVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs dynamic elements including a movable discharge tray that can shift between stacked and discharged positions, and a movable sheet support that adjusts to different sheet lengths. This dynamic configuration allows the device to adapt to various sheet lengths without requiring complex fixed structures like switchback conveyance paths or swing arms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent utilizes vertical space by stacking sheets in a layered arrangement within the discharge tray, and employs vertical movement of the discharge tray itself to transition between stacking and discharging states. This three-dimensional approach replaces the need for complex horizontal conveyance mechanisms.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If a switchback conveyance path stacker and swing arm are used to handle multiple sheet lengths, then the device can accommodate different sheet lengths, but the device size increases

Engineering Contradiction:
Improvecapability to handle different sheet lengthsVSAvoiddevice size
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent implements a nested structure where the sheet support is positioned within the discharge tray assembly, and the entire stacking mechanism is integrated into the printer body. This nesting allows multiple functional components to occupy overlapping spatial volumes, reducing the overall device footprint while maintaining the capability to handle different sheet lengths.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent utilizes vertical stacking space to accommodate sheets of different lengths, employing the vertical dimension rather than expanding horizontally. The discharge tray moves vertically to accommodate varying sheet lengths, allowing the device to maintain a compact horizontal footprint while handling diverse sheet sizes.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4209438B1Sheet transporting device
Publication Date: 2026.02.18 TOSHIBA TEC KK
  • EP4209438B1 patent drawingFigure 1
  • EP4209438B1 patent drawingFigure 2
  • EP4209438B1 patent drawingFigure 3

AI summary

A carrying-in unit moves a sheet in the length direction and feeds the sheet to a stacking unit. A lower conveyance unit constitutes at least a part of the bottom of the stacking unit and applies a force to the lower side of a sheet stacked on the stacking unit so as to move the sheet in the length direction. A lifting and lowering unit lifts and lowers at least an end of the lower conveyance unit on a side close to the carrying-in unit in at least three stages of a lower stage suitable for a case where the length of a handled sheet is a first length shorter than a distance from the carrying-in unit to a discharge unit, a middle stage suitable for a case where the length of a handled sheet is a second length longer than the first length, and an upper stage suitable for discharging a sheet. An upper conveyance unit faces the lower conveyance unit and applies a force to the upper side of the sheet pinched between the upper conveyance unit and the lower conveyance unit that is moved to the upper stage by the lifting and lowering unit, so as to move the sheet in the length direction. A stopper protrudes above the lower conveyance unit placed at the lower stage by the lifting and lowering unit, and the downstream end in the feeding direction of a sheet having the first length abuts on the stopper.