Fuser Roller Speed Control via Torque Feedback

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Solution Overview

Problem

In image forming apparatuses, the exchange of torque between rollers can lead to image quality deterioration and color shifts, particularly when handling papers with high weight capacity, due to differences in rotational speeds between the fuser roller and the transferring roller.

Innovation Solution

A system that includes a first and second rotating unit, driving units, rotational speed detecting and controlling units, and a torque information acquiring unit to adjust the rotational speed of the fuser roller based on torque comparisons when the paper is carried by both units, ensuring minimal torque exchange and maintaining consistent paper flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the rotational speed of the fuser roller and the transferring roller are separately controlled, then the productivity is improved by enabling independent speed adjustment, but the image quality deteriorates due to torque exchange and slippage between rollers

Engineering Contradiction:

Improveindependent speed adjustment capabilityVSAvoidimage quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system measures the actual loop amount (the amount by which the recording paper bridges between rollers) and uses this feedback to dynamically correct the rotational speed of the fuser roller. This closed-loop control ensures that torque exchange is minimized while maintaining independent speed control capability, thus preserving both productivity and image quality.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes the rotational speed parameter of the fuser roller dynamically based on the measured loop amount. By adjusting the speed parameter in real-time according to actual conditions (paper weight, bridging amount), the system prevents torque exchange and slippage while maintaining the ability to independently control roller speeds for productivity.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If the appropriate loop amount is stored in advance for correction, then the device complexity is reduced by using pre-stored values, but the measurement precision deteriorates because the correction amount may not match actual conditions

Engineering Contradiction:

Improvecorrection system simplicityVSAvoidloop amount measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system performs preliminary measurement of the loop amount (the amount by which recording paper bridges between rollers) before torque exchange occurs. This advance measurement allows the system to prepare the appropriate correction amount based on actual conditions, ensuring both simple device operation and high measurement precision by capturing the true loop amount rather than using generic pre-stored values.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses the actual loop amount measurement to determine its own correction needs without requiring external input or complex pre-programming. The measurement system serves the control system directly by providing real-time data about paper bridging, enabling automatic and precise speed correction tailored to each specific situation.

Inventive Principle:

Principle #25Self-service

3Productivity

If the recording paper bridges between the transferring roller and the fuser roller, then the productivity is improved by continuous paper flow, but the force balance deteriorates causing torque exchange and paper slippage

Engineering Contradiction:

Improvecontinuous paper flowVSAvoidtorque balance between rollers

Core Design Contradiction:

ProductivityVSForce

Solution Approach 1:

The system applies preliminary correction to the fuser roller speed before torque exchange and paper slippage occur. By measuring the loop amount in advance and adjusting the speed proactively, the system prevents the harmful torque exchange that would otherwise occur when paper bridges between rollers, thus maintaining both continuous paper flow and force balance.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system dynamically adjusts the rotational speed of the fuser roller based on real-time measurement of the loop amount. This dynamic control allows the system to maintain optimal speed relationships between rollers during continuous paper flow, adapting to varying paper weights and bridging conditions to prevent torque exchange while preserving continuous operation.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8465013B2Carrying apparatus, image forming apparatus, carried medium carrying method, computer readable medium storing computer program thereof

Publication Date: 2013.06.18 RICOH CO LTD

AI summary

A disclosed carrying apparatus includes a first rotating unit carrying a sheet-like carried medium in a rotating direction, a second rotating unit carrying the carried medium in the rotating direction, a first driving unit rotating the first rotating unit, a second driving unit rotating the second rotating unit, a first rotational speed detecting unit, a second rotational speed detecting unit, a first rotational speed controlling unit, a second rotational speed controlling unit, and a torque information acquiring unit acquiring torque information acting on the first rotating unit, wherein the second rotational speed controlling unit controls the second rotational speed in response to a comparison result between the torque information acquired when the sheet-like carried medium is solely carried by the first rotating unit and the torque information acquired when the sheet-like carried medium is carried by the first rotating unit and the second rotating unit.