Image Forming Fixing Unit Control During Sheet Cutting

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Solution Overview

Problem

The durability of the fixing unit in image forming devices is compromised due to localized temperature increases when the discharge roller stops, causing the heating and pressure rotation bodies to heat up, which is not addressed in existing technologies.

Innovation Solution

The controller controls the temperature and motor operations to prevent localized heating by setting the fixing unit to a lower temperature and rotating the heating and pressure rotation bodies after the cutting position reaches the cutter, ensuring they remain operational for continuous printing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the discharge roller stops to enable cutting of the sheet, then the cutting position can be accurately positioned, but the heating rotation body and pressure rotation body locally increase in temperature, decreasing the durability of the fixing unit

Engineering Contradiction:
Improvecutting position accuracyVSAvoidfixing unit durability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies dynamics by making the rotation bodies' operational state adjustable between stopped and rotating. The controller dynamically changes the rotation state of the heating rotation body and pressure rotation body based on the cutting process requirements, allowing them to rotate during cutting to prevent localized temperature increase while maintaining cutting position accuracy through coordinated control with the discharge roller

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the fixing unit by controlling the rotation speed and temperature of the heating rotation body and pressure rotation body. During the cutting process, the controller adjusts these parameters to maintain rotation and prevent temperature accumulation, thereby resolving the contradiction between positioning accuracy and component durability

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the heating rotation body and pressure rotation body stop rotating when the discharge roller stops, then energy consumption is reduced, but localized temperature increase occurs at the nip portion

Engineering Contradiction:
Improveenergy consumptionVSAvoidnip portion temperature
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The system dynamically adjusts the rotation state of the heating rotation body and pressure rotation body based on real-time operational requirements. During cutting operations, the controller maintains rotation of these components to prevent localized heating, while allowing rotation to be reduced or stopped during normal conveying to minimize energy consumption

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent ensures continuous useful action by maintaining the rotation of the heating rotation body and pressure rotation body during the cutting process. This continuous rotation prevents heat accumulation at the nip portion while the discharge roller stops for cutting, balancing energy consumption with thermal management requirements

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 prevents the heating and pressure rotation bodies from overheating, thereby maintaining the durability of the fixing unit and reducing the time required for continuous printing.

Implementation Method 1

a heater configured to heat the heating rotation body

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

heat is applied to a nip portion between the pair of rollers

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

convey the sheet having passed through the nip portion

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 4

a discharge roller disposed downstream of the fixing unit in a conveying direction of the sheet, and configured to discharge the sheet

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4628992A1Image forming device
Publication Date: 2025.10.08 BROTHER KOGYO KK
  • EP4628992A1 patent drawingFigure 1
  • EP4628992A1 patent drawingFigure 2
  • EP4628992A1 patent drawingFigure 3

AI summary

Provided is an image forming device capable of suppressing reduction in durability of a fixing part when cutting a sheet by a cutter. A control unit (101) causes a heating rotor (51) or a compressing rotor (52) to rotate to thereby convey a sheet, causes discharge rollers (36, 37) to rotate to thereby convey the sheet having passed through a nip (N), stops the discharge rollers when the cutting position in the sheet has reached the placement location (B) of a cutter, and after the stoppage of the discharge rollers, starts cutting of the sheet by the cutter (10) in a state where the heating rotor or the compressing rotor is rotating.