Fixing Rotor Thermal Management for Back Curl Reduction

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Solution Overview

Problem

In high-humidity and low-temperature environments, image forming apparatuses experience prolonged warm-up times and significant back curl of paper sheets due to the temperature difference between the image and non-image surfaces, which affects fixability and energy efficiency.

Innovation Solution

The pressure-side rotor has a longer contact time with the fixing-side rotor, allowing it to receive heat more efficiently and maintain a higher temperature, reducing the temperature difference and back curl, while preventing the need for the pressure-side rotor to reach excessively high temperatures, thus shortening the warm-up time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the pressure-side rotor is heated to sufficiently high temperature in high-humidity and low-temperature environment, then back curl is reduced, but warm-up time increases significantly

Engineering Contradiction:

Improveback curlVSAvoidwarm-up time

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The invention changes the operating parameters by controlling the temperature of the pressure-side rotor to be lower than conventional levels (maintaining 5°C to 20°C difference from fixing-side rotor), and adjusts the paper feed interval to allow thermal accumulation. This parameter optimization reduces warm-up time while preventing excessive back curl through controlled temperature differential rather than high temperature heating.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention implements periodic paper feeding with controlled intervals between sheets. This periodic action allows the pressure-side rotor to recover heat between feeding cycles, maintaining sufficient temperature for image fixation without requiring continuous high-temperature heating, thereby reducing overall warm-up time.

Inventive Principle:

Principle #19Periodic action

2Loss of time

If only the belt on the image surface side is heated in short time, then warm-up time is reduced, but temperature difference between front and back surfaces increases causing back curl

Engineering Contradiction:

Improvewarm-up timeVSAvoidback curl

Core Design Contradiction:

Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The pressure-side rotor serves as a thermal intermediary between the fixing-side rotor and the paper. By heating the pressure-side rotor to a moderate temperature and maintaining it through controlled paper feed intervals, it acts as a heat reservoir that reduces the temperature differential across the paper during fixation, preventing back curl without requiring extensive heating of both surfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention performs preliminary heating of the pressure-side rotor to a controlled temperature before paper feeding begins. This preliminary action ensures the pressure-side rotor is sufficiently warm to prevent back curl from the outset, eliminating the need for prolonged heating during operation.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the pressure-side rotor temperature is maintained high, then fixability is maintained, but energy consumption increases

Engineering Contradiction:

ImprovefixabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The invention optimizes the temperature parameter of the pressure-side rotor to a lower range (maintaining 5°C to 20°C difference from fixing-side rotor) while compensating with controlled paper feed intervals. This parameter change maintains sufficient fixability through thermal accumulation rather than high temperature, significantly reducing energy consumption.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The controlled paper feed intervals ensure continuous thermal action on the pressure-side rotor, allowing heat accumulation between feeds. This continuous useful action maintains fixability without requiring high temperatures, as the rotor continuously receives and retains heat for the next feeding cycle.

Inventive Principle:

Principle #20Continuity of useful action

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 approach reduces back curl and maintains fixability in high-humidity and low-temperature conditions without elongating the warm-up time, enhancing energy efficiency and productivity.

Implementation Method 1

the pressure-side rotor has a longer contact time with the fixing-side rotor. This makes the pressure-side rotor easily receive heat from the fixing-side rotor

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2031461B1Image forming apparatus

Publication Date: 2019.05.15 KONICA MINOLTA BUSINESS TECH INC

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AI summary

An image forming apparatus is provided with a feed interval control section that sets feed intervals of the recording materials, for a defined period from immediately after completion of the warm-up operation for a fixing-side rotor and the pressure-side rotor determined by a warm-up completion determination section, to be longer than feed intervals of the recording materials posterior to the defined period in a high-humidity and low-temperature state. Thereby, the image forming apparatus prevents elongation of a warm-up time while achieving both reduction of the back curl and maintenance of fixability in the high-humidity and low-temperature state.