Image Formation Device: Noncontact Preheating for Toner Protection

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Solution Overview

Problem

In electrophotographic image forming devices, when forming images on both sides of a recording medium, the preheating unit heats the first surface to above the toner's softening point, causing the toner on the first surface to become soft, leading to damage when the image forming region comes into contact with members other than the recording medium during the process.

Innovation Solution

The image forming device employs a preheating unit that heats the recording medium in a non-contact state, ensuring the first surface is above the toner's softening point without direct contact with other members, and uses a fan to stabilize the medium's posture, preventing contact and damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the preheating unit heats the recording medium to above the toner's softening point, then the toner image fixing quality is improved, but the toner image on the first surface becomes soft and susceptible to damage

Engineering Contradiction:
Improvetoner image fixing qualityVSAvoidtoner image damage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

A fan is introduced as an intermediary device to blow air and stabilize the recording medium's posture during the heating process. This mediator prevents direct contact between the softened toner image and supporting members, eliminating the damage mechanism while allowing the heating process to proceed for quality fixing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The fan operates beforehand and continuously during the heating process to create a protective airflow environment. This prior cushioning of air pressure prevents the recording medium from sagging or contacting other members, protecting the softened toner image before damage can occur.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Manufacturing precision

If the recording medium is heated from the first surface side, then the toner image is fixed properly, but the toner image on the first surface is damaged due to contact with members

Engineering Contradiction:
Improvetoner image fixing qualityVSAvoidtoner image integrity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The heating approach is inverted from heating the first surface to heating the second surface. This reversal allows the toner image on the first surface to be protected from contact damage while the second surface heating still achieves proper fixing quality through the softened toner.

Inventive Principle:
Principle #13The other way round (Inversion)

3Device complexity

If the recording medium is conveyed in a bent state by gravity, then the apparatus layout is simplified, but the region where members can be arranged is reduced

Engineering Contradiction:
Improveapparatus layoutVSAvoidmember arrangement region
Core Design Contradiction:
Device complexityVSArea of stationary object

Solution Approach 1:

A fan system using pneumatic principles is employed to blow air and support the recording medium in a non-bent state. This pneumatic support replaces the need for gravity-induced bending, maintaining a flat conveyance path that increases the available region for arranging apparatus members.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 prevents toner image damage on the first surface and enhances glossiness on the second surface while allowing for increased apparatus layout flexibility and reduced preheating unit output requirements.

Implementation Method 1

a preheating unit that heats the recording medium in a non-contact state

Methodology Applied
Scientific EffectThermal radiation heating: Thermal Radiation

Implementation Method 2

uses a fan to stabilize the medium's posture, preventing contact and damage

Methodology Applied
Scientific EffectAir flow stabilization: Fan

Data Source

PatentEP3926410B1Image formation device
Publication Date: 2025.08.06 FUJIFILM BUSINESS INNOVATION CORP
  • EP3926410B1 patent drawingFigure 1
  • EP3926410B1 patent drawingFigure 2
  • EP3926410B1 patent drawingFigure 3

AI summary

An image formation device provided with: an auxiliary heating section that is arranged between a transfer section and a main heating section along the conveyance direction of a recording medium and that, when heating the recording medium having a toner image transferred to a second surface thereof, heats the recording medium in a non-contact state before the main heating section heats the recording medium so that the temperature of the first surface of the recording medium is higher than the softening point of the toner; and a noncontacting means for preventing contact between a toner image formation region on a first surface of the recording medium having the toner image transferred to the second surface and members other than the recording medium across the auxiliary heating section to the main heating section.