Image Forming Apparatus Sheet Conveyance Control

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Solution Overview

Problem

Conventional image forming apparatuses require temporary shutdown and manual removal of recording sheets during conveyance failures, such as jamming, unreached, or accumulated statuses, which disrupts high-speed printing operations and prolongs restoration times.

Innovation Solution

The apparatus employs sensors to detect minor conveyance delays and continues sheet conveyance without stopping the system, allowing for the discharge of remaining sheets and minimizing downtime by classifying delays into normal, minor, and major categories to execute 'jam clear conveyance' operations, thereby reducing the need for immediate shutdowns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the apparatus stops to remove recording sheets during conveyance failure, then the reliability of sheet handling is improved, but the productivity and printing speed deteriorate due to shutdown time

Engineering Contradiction:
Improvesheet handling reliabilityVSAvoidprinting speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts its response to conveyance failures based on the severity and type of failure detected. For minor failures like unreached or accumulated statuses, the system continues operation with modified conveyance. For major failures like jamming, it stops to remove sheets. This dynamic decision-making resolves the contradiction by adapting the reliability-productivity tradeoff to each specific failure condition.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the conveyance parameters (speed, continuation vs. stop) based on the detected failure type. By categorizing failures into minor (unreached, accumulated) and major (jamming) types, the system applies different parameter settings: continuing conveyance for minor failures maintains productivity, while stopping for major failures ensures reliability.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the apparatus continues conveyance without stopping during minor failures, then the productivity is maintained, but the risk of sheet damage or further jamming increases

Engineering Contradiction:
Improveprinting speedVSAvoidsheet damage risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically monitors sheet conveyance status and adjusts its operation in real-time. When unreached or accumulated statuses are detected, the system continues conveyance with modified parameters. If the condition worsens or becomes a major jamming failure, it transitions to stop-and-remove mode. This dynamic adjustment manages the risk while maintaining productivity for recoverable conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses sensors to continuously feedback sheet position and conveyance status. Based on this feedback, it determines whether to continue or stop conveyance. The feedback mechanism allows the system to detect minor failures early and respond appropriately, preventing them from escalating into sheet-damaging major failures while maintaining productivity when safe to do so.

Inventive Principle:
Principle #23Feedback

3Reliability

If all conveyance failures are treated as major failures requiring shutdown, then the sheet handling reliability is improved, but the loss of time for restoration increases

Engineering Contradiction:
Improvesheet handling reliabilityVSAvoidrestoration time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system segments conveyance failures into distinct categories: minor failures (unreached, accumulated statuses) and major failures (jamming). This segmentation allows differentiated responses: minor failures are handled by continued conveyance with minimal or no restoration time, while major failures trigger shutdown and manual intervention. The segmentation resolves the contradiction by applying appropriate restoration procedures only when necessary.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the operational parameter from 'stop and remove' to 'continue conveyance' based on failure type. For minor failures, the parameter change allows the apparatus to maintain operation with minimal disruption, significantly reducing restoration time compared to universal shutdown approaches, while still ensuring reliability through appropriate handling of major failures.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If the apparatus removes deflected or skewed sheets immediately, then the occurrence of jamming is reduced, but the productivity decreases due to sheet removal operations

Engineering Contradiction:
Improvejamming preventionVSAvoidprinting speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system applies different quality standards and handling approaches to different sheet conditions. For deflected or skewed sheets that are not severe enough to cause jamming, the system allows continued conveyance with local adjustments. For sheets with severe deflection that would definitely cause jamming, it removes them. This local quality approach maintains productivity for minor deviations while preventing jamming when necessary.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2141548B1Image forming apparatus
Publication Date: 2020.01.15 RICOH CO LTD
  • EP2141548B1 patent drawingFigure 1
  • EP2141548B1 patent drawingFigure 2
  • EP2141548B1 patent drawingFigure 3~4

AI summary

Disclosed is an image forming apparatus that includes a recording medium feeding unit that feeds a recording medium to a predetermined conveyance path; a conveyance unit that conveys the recording medium fed from the recording medium feeding unit on the conveyance path; a conveyance status detection unit that detects a conveyance status of the recording medium placed on the conveyance path; a control unit that controls operations of the recording medium feeding unit, the conveyance unit, and the conveyance status detection unit; and an accommodation unit that accommodates the recording medium. The control unit controls the feeding of the recording medium with the recording medium feeding unit and the conveyance of the recording medium with the conveyance unit based on a detection result of the conveyance status detection unit, thereby discharging the recording medium present in the image forming apparatus to the accommodation unit.