Sheet Stacking Conveyor Control for Variable-Length Print Jobs

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Solution Overview

Problem

Existing sheet stacking systems face inefficiencies in stacking capacity and retrieval workability due to fixed grip unit distances, leading to either excessive spacing or overlapping of sheets of varying lengths.

Innovation Solution

A control method and apparatus that dynamically adjusts the conveyor feed based on sheet detection and job status, ensuring optimal spacing and alignment of sheets by varying the conveyor feed amount according to the discharge pattern of the printing apparatus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the distance between grip units is fixed, then the structure is simple and easy to manufacture, but sheets of varying lengths either have excessive spacing or overlap, reducing stacking capacity and retrieval workability

Engineering Contradiction:
Improveease of manufactureVSAvoidstacking capacity
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies dynamics by making the grip unit spacing adjustable rather than fixed. The control unit dynamically changes the distance between grip units based on the length of sheets being processed, allowing the system to adapt to different sheet sizes and maximize stacking capacity without overlapping issues

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of grip unit spacing based on sheet length. The control unit receives sheet length information and adjusts the distance between grip units accordingly, transforming a static parameter into a variable one that optimizes stacking efficiency for different sheet dimensions

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the distance between grip units is fixed, then the device complexity is low, but sheets of varying lengths either have excessive spacing or overlap, reducing retrieval workability

Engineering Contradiction:
Improvedevice complexityVSAvoidretrieval workability
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The system dynamically adjusts grip unit spacing to prevent sheet overlapping, which directly improves retrieval workability. By making the spacing variable rather than fixed, the system ensures that sheets are properly separated regardless of their length, making retrieval easier without significantly increasing device complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control unit receives feedback about sheet length and uses this information to adjust grip unit spacing. This feedback mechanism ensures that the spacing is optimized for each sheet size, preventing overlapping and improving retrieval workability while maintaining reasonable device complexity

Inventive Principle:
Principle #23Feedback

3Device complexity

If the conveyor moves by a fixed predetermined amount, then the control is simple, but the stacking capacity is reduced when sheets are shorter than the distance between grip units

Engineering Contradiction:
Improvecontrol complexityVSAvoidstacking capacity
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent changes the conveyor feed amount parameter based on sheet length. The control unit adjusts this parameter dynamically, receiving sheet length information and setting the conveyor feed amount accordingly, which maximizes stacking capacity by ensuring optimal spacing for each sheet size

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system transitions from static fixed-step conveyor movement to dynamic variable-step movement. The control unit dynamically determines the conveyor feed amount based on real-time sheet length information, allowing the system to adapt to different sheet sizes and improve stacking capacity

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4043376B1Sheet stacking apparatus, printing apparatus, control method, and corresponding computer program
Publication Date: 2025.09.03 CANON KK
  • EP4043376B1 patent drawingFigure 1~2
  • EP4043376B1 patent drawingFigure 3~4
  • EP4043376B1 patent drawingFigure 5A~5C

AI summary

A sheet stacking apparatus is provided. A conveyor means (23) performs stacking of sheets discharged from a printing apparatus (100) and conveying of stacked sheets. A detection means (24) detects whether or not the printing apparatus (100) is currently discharging a sheet. A control means (26), so as to secure a stacking space for a sheet discharged from the printing apparatus (100) on the conveyor means (23), controls a feeding operation of the conveyor means correspondingly to a period of time over which the detection means (24) detected that the printing apparatus (100) is discharging a sheet.