Sheet Processing Apparatus Center-Folding Stability

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Solution Overview

Problem

Existing sheet processing apparatuses face reliability issues during center-folding processes, as unbound sheets are not securely held by conveying rollers, leading to instability and potential jams, especially when handling a large number of sheets.

Innovation Solution

The apparatus controls the sheet processing unit to perform center-folding by limiting the number of sheets to be folded to a stable unit size, such as five sheets, and uses a division binding function to ensure proper alignment and output, preventing sheet shifting and jams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of sheets to be conveyed is increased in a center-folding process, then productivity is improved, but reliability deteriorates due to sheet shifting and instability

Engineering Contradiction:
Improvenumber of sheets processedVSAvoidconveyance stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent divides a large number of sheets into multiple smaller bundles, each containing a predetermined number of sheets (e.g., 5 sheets per bundle). This segmentation allows the folding apparatus to process sheets in manageable units that maintain stability during conveyance, while still achieving high overall productivity by processing multiple bundles sequentially. The segmentation resolves the contradiction by enabling reliable handling of smaller units while maintaining the capability to process large total volumes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a binding process as an intermediary step between sheet preparation and folding. By binding sheets together (e.g., using staples or adhesive) before folding, the sheets form a stable composite structure that prevents shifting during conveyance. This intermediary binding action serves as a mediator that enables reliable conveyance of larger sheet bundles, resolving the stability issue while maintaining productivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the number of sheets in a bundle is increased, then productivity is improved, but manufacturing precision deteriorates due to improper alignment

Engineering Contradiction:
Improveprocessing volumeVSAvoidsheet alignment
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments sheets into smaller bundles with a predetermined number of sheets (e.g., 5 sheets per bundle) that can be properly aligned and handled. This segmentation ensures that each bundle maintains proper sheet alignment during the folding process, preventing manufacturing precision deterioration while still achieving high productivity through batch processing of multiple segmented bundles.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary alignment and binding of sheets into properly organized bundles before the folding process. By pre-organizing sheets into stable, aligned bundles with a predetermined number of sheets, the system ensures that alignment precision is maintained during subsequent folding operations, while the bundled format enables efficient high-volume processing.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the number of sheets to be conveyed is increased, then productivity is improved, but device complexity increases due to additional control mechanisms

Engineering Contradiction:
Improvenumber of sheets processedVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent uses segmentation of sheets into standardized small bundles as a simple mechanical approach to enable high productivity without complex control systems. The predetermined bundle size (e.g., 5 sheets) creates a natural processing unit that simplifies conveyance control, allowing the system to handle large numbers of sheets through repetitive processing of standardized units rather than requiring complex individual sheet management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The binding process creates self-contained bundles that maintain their integrity and alignment automatically during conveyance. These self-organized bundles require minimal active control during the folding process, as their bound structure inherently prevents sheet shifting and misalignment. This self-service characteristic reduces the need for complex control mechanisms while maintaining high processing capacity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3431426B1Sheet processing apparatus, method for controlling the same, and storing medium
Publication Date: 2021.10.13 CANON KK
  • EP3431426B1 patent drawingFigure 1
  • EP3431426B1 patent drawingFigure 2
  • EP3431426B1 patent drawingFigure 3

AI summary

When an apparatus capable of executing a saddle-stitching binding process and a center-folding binding process executes the center-folding binding process, sheets are stably conveyed. A control method for controlling a sheet processing apparatus includes causing a sheet processing unit to perform a saddle-stitching binding process in which a plurality of sheets are subjected to a binding process and a folding process or a center-folding binding process in which a plurality of sheets are not subjected to the binding process but subjected to the folding process, permitting the sheet processing unit to perform the saddle-stitching binding process or the center-folding binding process on a predetermined number of sheets, and controlling such that the number of sheets which are permitted to be subjected to the center-folding binding process is smaller than the number of sheets which are permitted to be subjected to the saddle-stitching binding process.