Fixing Device Non-Contact Heating and Variable Pressing

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Solution Overview

Problem

Existing fixing devices for image forming apparatuses often apply excessive pressing force on recording media, leading to wrinkles and misregistration of toner images, and require higher fixing temperatures and longer rising times due to inefficient heating and pressing mechanisms.

Innovation Solution

A fixing device with a first belt and a second belt forming a nip region, where the first belt is rotated by a driving roller and heated by a halogen lamp in a non-contact manner, and the second belt is pressed by a pressing member, allowing for a variable pressing force and efficient heat distribution through a reflective surface and holder structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional fixing device applies high pressing force to ensure proper fixing, then the fixing reliability is improved, but the recording medium develops wrinkles and toner image misregistration occurs

Engineering Contradiction:

Improvefixing reliabilityVSAvoidtoner image positioning accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary heating to the recording medium before it enters the nip region where pressing force is applied. By pre-heating the medium upstream, the toner becomes more pliable and adheres better under subsequent pressing, achieving reliable fixing without requiring excessive pressing force that would cause wrinkles or misregistration

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the temperature parameter by introducing a dedicated heating unit that raises the temperature of the recording medium before fixing. This temperature parameter change allows the fixing process to occur at lower pressing forces, resolving the contradiction between fixing reliability and image positioning accuracy

Inventive Principle:

Principle #35Parameter changes

2Temperature

If conventional heating mechanisms are used to heat the recording medium, then the fixing temperature is achieved, but the heating efficiency is low and rising time is long

Engineering Contradiction:

Improvefixing temperatureVSAvoidheating rising time

Core Design Contradiction:

TemperatureVSLoss of time

Solution Approach 1:

The heating unit is positioned upstream of the nip region to perform preliminary heating of the recording medium before it reaches the fixing zone. This advance heating reduces the thermal mass that needs to be heated at the critical fixing moment, significantly reducing the heating rising time while maintaining effective fixing temperature

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces conventional contact-based heating mechanisms with a non-contact heating unit (such as infrared or laser heating). This substitution eliminates heat transfer inefficiencies associated with mechanical contact, achieving faster and more efficient heating of the recording medium

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Use of energy by moving object

If conventional contact-based heating is used, then heating can be applied, but heat distribution is inefficient and energy loss increases

Engineering Contradiction:

Improveheating efficiencyVSAvoidheat loss

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent replaces mechanical contact-based heating with non-contact radiant heating (infrared or laser). This substitution eliminates energy losses associated with thermal conduction through intermediate materials and improves overall heating efficiency by directly energizing the recording medium and toner particles

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The heating unit is positioned to apply heat locally and selectively to the recording medium surface where the toner is located. This localized heating approach concentrates energy where it is most needed, improving heating efficiency and reducing energy loss to surrounding areas

Inventive Principle:

Principle #3Local quality

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 minimizes pressing force on the recording medium, reduces the risk of wrinkles, allows for lower fixing temperatures, and enhances heating efficiency, resulting in stable image formation and reduced misregistration.

Implementation Method 1

a heating unit that is provided inside the first belt in a region at an upstream side in the transport direction of the nip region in a non-contact manner with respect to the first belt, and heats the developer image on the recording medium

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentUS20170248886A1Fixing device and image forming apparatus

Publication Date: 2017.08.31 FUJIFILM BUSINESS INNOVATION CORP

AI summary

A fixing device includes a first belt that contacts a developer image on a recording medium; a second belt that sandwiches the recording medium with the first belt and hence forms a nip region extending in a transport direction of the recording medium; a rotational body that is provided inside the first belt in a region at a downstream side in the transport direction of the nip region, rotates, and turns the first belt; a pressing member that is provided inside the second belt and presses the second belt toward the rotational body; and a heating unit that is provided inside the first belt in a region at an upstream side in the transport direction of the nip region in a non-contact manner with respect to the first belt, and heats the developer image on the recording medium.