Sheet Post-Processing Device Curl Suppression

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Solution Overview

Problem

Existing sheet post-processing devices face challenges in suppressing curl and pushing out of sheet bundles during discharge, while maintaining processing efficiency, especially when dealing with varying numbers of sheets in a bundle.

Innovation Solution

The device incorporates a discharge roller pair and a reciprocatable bundle discharge member, with a control system that adjusts the discharge method based on the number of sheets in the bundle, using the discharge roller pair for smaller bundles and the bundle discharge member for larger ones, and includes a lifting-lowering mechanism for the loading tray to manage curl and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the discharge roller pair is used to discharge sheet bundles, then processing efficiency is improved, but curl and pushing out of sheet bundles cannot be suppressed

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidcurl suppression
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies dynamics by making the discharge mechanism adaptable - using discharge rollers for small bundles and a bundle discharge member for large bundles. The system dynamically selects the appropriate discharge method based on bundle size, allowing both high-speed discharge for small bundles and reliable curl suppression for large bundles

Inventive Principle:
Principle #15Dynamics

2Reliability

If the bundle discharge member is used to discharge sheet bundles, then curl and pushing out are suppressed, but processing efficiency decreases

Engineering Contradiction:
Improvecurl suppressionVSAvoidprocessing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically selects between two discharge methods based on bundle size. The bundle discharge member is used specifically for large bundles where curl suppression is critical, while the discharge rollers handle small bundles for high efficiency, optimizing overall system performance

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If the loading tray is lifted above the reference position, then alignment and curl control are improved, but device complexity increases

Engineering Contradiction:
Improvealignment precisionVSAvoidmechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The loading tray is preliminarily positioned (lifted) before the bundle discharge operation to prevent curl and ensure proper alignment during discharge. This preliminary positioning action ensures that when large bundles are discharged, they land correctly without curling or pushing out

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3778458B1Sheet post-processing device and image forming system provided therewith
Publication Date: 2022.09.14 KYOCERA DOCUMENT SOLUTIONS INC
  • EP3778458B1 patent drawingFigure 1
  • EP3778458B1 patent drawingFigure 2
  • EP3778458B1 patent drawingFigure 3

AI summary

A sheet post-processing device (5) includes a processing tray (8), a post-processing mechanism (61, 62), a discharge roller pair (73), a bundle discharge member (81), a loading tray (11), a sheet holding member (14), a discharge drive portion (90), a tray lifting-lowering drive portion (113), a sheet holding drive portion (142), and a control portion (100). In a case where a number A of sheets included in a sheet bundle loaded on the processing tray (8) is smaller than a predetermined number A1, the control portion (100) discharges the sheet bundle onto the loading tray (11) by using the discharge roller pair (73), with the loading tray (11) arranged at a reference position. In a case where the number A of the sheets included in the sheet bundle is equal to or larger than the predetermined number A1, the control portion (100) discharges the sheet bundle onto the loading tray (11) by using the bundle discharge member (81), with the loading tray (11) having been lifted above the reference position.