Interlocking Pressure Mechanism for Straight-Through Image Fixing

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Solution Overview

Problem

Existing image forming apparatuses with straight-through paths fail to adequately perform thermal image fixing on thicker recording media and complicate the removal of jammed media due to separation of heat and pressure rollers.

Innovation Solution

An image forming apparatus with a fixing unit featuring a heating member and a backup member, supported by a pressure mechanism, and an interlocking mechanism that adjusts the relative positions of these components to maintain contact during printing and facilitate easy ejection of jammed media by reducing pressure between the rollers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the heat roller and pressure roller are separated to facilitate jammed medium removal, then ease of operation is improved, but thermal image fixing quality deteriorates

Engineering Contradiction:
Improvejammed medium removalVSAvoidthermal image fixing quality
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The pressure roller is designed to be movable relative to the heat roller through a pressure mechanism. During normal operation, the pressure roller maintains contact with the heat roller for proper thermal fixing. When a cover is opened, the interlocking mechanism causes the pressure roller to move away from the heat roller, allowing easy removal of jammed media. This dynamic adjustment resolves the contradiction between maintaining fixing quality and enabling easy jam removal.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If the heat roller and pressure roller remain in contact during cover opening, then thermal image fixing is maintained, but jammed medium removal becomes difficult

Engineering Contradiction:
Improvethermal image fixing qualityVSAvoidjammed medium removal
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The pressure mechanism enables the pressure roller to dynamically adjust its position. During cover opening for media removal, the interlocking mechanism actuates the pressure mechanism to move the pressure roller away from the heat roller, reducing friction and allowing easy media extraction. This dynamic separation resolves the contradiction between maintaining contact for fixing quality and separating for ease of media removal.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the pressure mechanism is made movable to adjust roller positions, then ease of operation is improved, but device complexity increases

Engineering Contradiction:
Improveroller position adjustmentVSAvoidpressure mechanism structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The pressure mechanism is integrated with the interlocking mechanism that already exists for cover opening/closing operations. The same interlocking mechanism that controls cover movement also actuates the pressure mechanism to adjust roller positions. This merging of functions reduces overall device complexity while maintaining the benefit of adjustable roller positions for ease of operation.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If the interlocking mechanism controls pressure roller position, then ease of operation is improved, but device complexity increases

Engineering Contradiction:
Improvecover operation coordinationVSAvoidinterlocking mechanism structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The interlocking mechanism is designed to perform multiple functions: it controls the opening/closing of covers and simultaneously actuates the pressure mechanism to adjust pressure roller positions. This multi-functionality eliminates the need for separate control mechanisms, reducing overall device complexity while improving ease of operation through coordinated roller position adjustment.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Ensures sufficient thermal image fixing of thicker media in a straight-through path while allowing easy removal of jammed media by adjusting the pressure mechanism's positions in response to cover openings.

Implementation Method 1

a heating member configured to heat a recording sheet

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 2

a backup member configured to rotate and contact the heating member

Methodology Applied
Scientific EffectMechanical pressure: Compression

Data Source

PatentEP2492759B1Image forming apparatus
Publication Date: 2017.08.02 BROTHER KOGYO KK
  • EP2492759B1 patent drawingFigure 1
  • EP2492759B1 patent drawingFigure 2
  • EP2492759B1 patent drawingFigure 3

AI summary

An image forming apparatus includes a fixing unit having a heating member that heats a recording medium, a backup member that rotates and contacts the heating member, and a pressure mechanism that supports one of the heating member and the backup member such that the one of the heating member and the backup member moves relative to the other. The apparatus includes a main body including the fixing unit inside, and has a first opening on a downstream side of the fixing unit and a second opening on a side of the main body different from the first opening. Also the apparatus has first and second covers that open and close the first and second openings, respectively, and an interlocking mechanism that causes the pressure mechanism to move the one of the heating member and the backup member in conjunction with movement of the first cover and the second cover.