Sheet Carrier Drawer Control for Tearing Jam Prevention

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Solution Overview

Problem

Existing image forming apparatuses face issues with sheet tearing jams when a sheet is suspended between drawable and non-drawable parts of the sheet carrying passage, and existing solutions increase costs due to additional sensors and mechanisms.

Innovation Solution

A sheet carrier device with roller pairs, a sheet detection system, and a control device that determines the presence of sheets in tearing jams using existing sensors, and performs targeted sheet removal processes to prevent tearing jams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a user draws out the drawable part of the sheet carrying passage to remove a jam, then the jam is released, but a sheet may be torn causing a tearing jam

Engineering Contradiction:
Improvejam release operationVSAvoidsheet integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The control device determines whether a sheet is located in a tearing jam place before the user draws out the drawer device. Based on this determination, the control device performs a tearing jam releasing process that carries the sheet to a safe position before allowing drawer extraction, preventing the sheet from being torn during user operation.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If additional sensors and mechanisms are added to detect and prevent tearing jams, then sheet tearing is prevented, but device complexity and cost increase

Engineering Contradiction:
Improvetearing jam preventionVSAvoidsensor and mechanism count
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention uses existing sensors in the image forming apparatus that serve multiple functions: they detect both general sheet jams and tearing jam conditions. The control device repurposes these existing detection capabilities to determine sheet positions and prevent tearing jams, eliminating the need for dedicated additional sensors while maintaining reliable tearing prevention.

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

3Reliability

If the drawer device is locked to prevent tearing jams, then sheet tearing is prevented, but ease of operation is reduced

Engineering Contradiction:
Improvetearing jam preventionVSAvoiddrawer accessibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The control device continuously monitors sheet positions using existing sensors and provides feedback control. When a sheet is detected in a tearing jam place, the control device activates the tearing jam releasing process. Once the sheet is safely positioned, the system allows normal drawer operation, providing dynamic feedback-based control that prevents tearing while maintaining user accessibility.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4641304A1Sheet carrier device and image forming system
Publication Date: 2025.10.29 KYOCERA DOCUMENT SOLUTIONS INC
  • EP4641304A1 patent drawingFigure 1
  • EP4641304A1 patent drawingFigure 2
  • EP4641304A1 patent drawingFigure 3

AI summary

A sheet carrier device (200) includes a sheet carrying passage (17, 210), roller pairs (17A, 220A, 220B, 220C, 220D, 220E), a sheet detection device (19, 240), and a control device (100). The sheet carrying passage (17, 210) includes a part configured as a drawable drawer device (230). The roller pairs (17A, 220A, 220B, 220C, 220D, 220E) carry a sheet along the sheet carrying passage (17, 210). The sheet detection device (19, 240) detects whether there is the sheet which is being carried along the sheet carrying passage (17, 210). The control device (100) determines whether there is the sheet located in a tearing jam place between the inside and the outside of the drawer device (230) at a time point at which a jam occurs on the basis of a result of detection from the sheet detection device (19, 240) and performs a tearing jam releasing process of removing the sheet from the tearing jam place when it is determined that there is the sheet.