Externally Heated Fuser Roller Layering

Solution Overview

Problem

Existing externally heated fusers face challenges in achieving fast warm-up times while maintaining high print quality and reliable operation, as they often require a trade-off between thermal response time and toner release ability.

Innovation Solution

A fuser member design incorporating a rigid core, a heat insulation layer, and a heat transport layer with specific thickness and thermal properties, along with an optional release layer, to facilitate efficient heat transfer and maintain favorable nip geometry for effective toner fusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the elastomeric layer is made thin to achieve fast thermal response time, then warm-up time is reduced, but toner release ability deteriorates

Engineering Contradiction:

Improvewarm-up timeVSAvoidtoner release ability

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The fuser roller is segmented into multiple functional layers: a thin heat transport layer (0.05-0.5 mm) for fast thermal response, and a separate heat insulation layer with specific effusivity (1-500 W√s/(m2K)) to maintain favorable nip geometry and ensure reliable toner release. This segmentation allows each layer to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different layers of the fuser roller are assigned different thermal properties: the heat transport layer has high thermal conductivity for rapid heat delivery, while the heat insulation layer has low effusivity to prevent heat loss and maintain contact pressure. This local differentiation of material properties enables simultaneous achievement of fast warm-up and reliable toner release.

Inventive Principle:

Principle #3Local quality

2Reliability

If the elastomeric layer is made thick to ensure good toner release ability, then print quality is improved, but thermal response time increases

Engineering Contradiction:

Improvetoner release abilityVSAvoidwarm-up time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The fuser roller is segmented into multiple functional layers: a thin heat transport layer (0.05-0.5 mm) for fast thermal response, and a separate heat insulation layer with specific effusivity (1-500 W√s/(m2K)) to maintain favorable nip geometry and ensure reliable toner release. This segmentation allows each layer to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different layers of the fuser roller are assigned different thermal properties: the heat transport layer has high thermal conductivity for rapid heat delivery, while the heat insulation layer has low effusivity to prevent heat loss and maintain contact pressure. This local differentiation of material properties enables simultaneous achievement of fast warm-up and reliable toner release.

Inventive Principle:

Principle #3Local quality

3Loss of time

If internally heated fuser design is used to achieve fast thermal response, then warm-up time is reduced, but structural complexity increases

Engineering Contradiction:

Improvewarm-up timeVSAvoidfuser structure

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

Instead of placing the heat source inside the fuser roller (internal heating), the patent uses external heating where the heater is positioned outside the roller. This inversion simplifies the fuser structure by eliminating the need for internal heating elements and their associated control systems, while still achieving fast thermal response through the thin heat transport layer design.

Inventive Principle:

Principle #13The other way round (Inversion)

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

The design achieves fast warm-up times and high print quality by optimizing the heat transport and insulation layers, ensuring efficient heat transfer and toner release, with warm-up times under 30 seconds and improved fuser reliability.

Implementation Method 1

an external heater for applying heat to the fuser member

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a heat transport layer, the heat transport layer having a thickness of about 0.05 to about 0.5 mm and a total thermal capacity of about 1 to about 200 J/mK

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

a heat insulation layer, the heat insulation layer having an effusivity value from about 1 to about 500 W√s/(m2K)

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS8718526B2High fusing performance externally heated fuser roller

Publication Date: 2014.05.06 LEXMARK INTERNATIONAL INC

AI summary

An externally heated fuser roller to achieve good fusing performance, long life and relatively quick warm-up time. The fuser roller is made up of a metal core, an insulation elastic layer, a heat transport layer and optionally a release layer such that the thickness of the heat transport layer is in the range of about 0.25 and about 1 mm, the effusivity value of the heat transport layer be equal to or greater than about 800 W√s(m2K), the total thermal capacity of the heat transport layer is less than about 200 J/m K, and the effusivity value of the insulation elastic layer is less than about 400 W√s(m2K).