Image Forming Apparatus Heating Roll Torque Stabilization

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Solution Overview

Problem

In image forming apparatuses, the synchronization of rotation between the pressing cylinder and the transfer cylinder leads to fluctuations in rotation speed due to variations in load torque, affecting the stability and efficiency of the image transfer process.

Innovation Solution

The implementation of an approach and separation mechanism, coupled with a suppression unit that includes cam members and cam followers, helps to mitigate the fluctuation in load torque acting on the pressing cylinder, thereby stabilizing the rotation speed of the transfer cylinder.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the heating roll is caused to approach and separate from the pressing cylinder using a cam mechanism, then the image transfer process can be controlled, but load torque fluctuation occurs on the pressing cylinder

Engineering Contradiction:
Improvecontrol of heating roll approach and separationVSAvoidrotation speed stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies the counterweight principle by introducing a suppression unit with a cam follower that presses against a suppression cam surface. This cam follower generates a counteracting force that opposes the load torque fluctuation caused by the heating roll's approach and separation motion, thereby stabilizing the pressing cylinder's rotation speed and preventing fluctuations from being transmitted to the transfer cylinder.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent employs asymmetric cam surface designs where the approach cam surface and separation cam surface have different geometries. The approach cam surface is designed to guide the heating roll smoothly toward the pressing cylinder, while the separation cam surface is configured to facilitate clean separation. This asymmetric design optimizes the motion control while managing the load torque characteristics during different phases of the cycle.

Inventive Principle:
Principle #4Asymmetry

2Productivity

If the rotation of the pressing cylinder and transfer cylinder are synchronized, then the image transfer efficiency is improved, but fluctuation in rotation speed of the pressing cylinder causes fluctuation in rotation speed of the transfer cylinder

Engineering Contradiction:
Improveimage transfer efficiencyVSAvoidrotation speed stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The suppression unit acts as a counterweight mechanism that compensates for the asymmetric load torque variations during the heating roll's approach and separation. By generating an opposing moment through the cam follower pressing against the suppression cam surface, the system maintains more uniform rotation speed in the pressing cylinder, ensuring stable synchronized operation with the transfer cylinder while preserving high image transfer efficiency.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The cam-based suppression mechanism provides mechanical feedback by continuously adjusting the load on the pressing cylinder based on the heating roll position. The cam follower detects the position-dependent load variations and automatically generates compensating forces through the cam profile geometry, creating a self-regulating system that maintains rotation speed stability without requiring external sensors or control systems.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration effectively suppresses the fluctuation in rotation speed at the transfer cylinder, enhancing the stability and efficiency of the image transfer process while maintaining a simple and cost-effective design.

Implementation Method 1

an approach and separation mechanism that includes a cam member that rotates together with the pressing cylinder and a cam follower that is connected to the heating roll and that is pressed against a cam surface of the cam member

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 2

a suppression unit that suppresses load torque that acts on the pressing cylinder since the approach and separation mechanism causes the heating roll to approach the pressing cylinder and to be separated from the pressing cylinder

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4530749A1Image forming apparatus
Publication Date: 2025.04.02 FUJIFILM BUSINESS INNOVATION CORP
  • EP4530749A1 patent drawingFigure 1
  • EP4530749A1 patent drawingFigure 2
  • EP4530749A1 patent drawingFigure 3

AI summary

An image forming apparatus includes: a transfer cylinder that sandwiches a transported recording medium while rotating and that transfers an image onto the recording medium, the recording medium being sandwiched between the transfer cylinder and a transfer member onto which the image is transferred; a heating roll that is disposed downstream of the transfer cylinder in a transport direction of the recording medium and that heats the transported recording medium while rotating; a pressing cylinder that is disposed to face the heating roll, that rotates in synchronization with rotation of the transfer cylinder, and that presses the transported recording medium toward the heating roll; an approach and separation mechanism that includes a cam member that rotates together with the pressing cylinder and a cam follower that is connected to the heating roll and that is pressed against a cam surface of the cam member, the approach and separation mechanism causing the heating roll to approach the pressing cylinder and to be separated from the pressing cylinder; and a suppression unit that suppresses load torque that acts on the pressing cylinder since the approach and separation mechanism causes the heating roll to approach the pressing cylinder and to be separated from the pressing cylinder.