Fixing Device Heating Member Reinforcement and Sealing

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Solution Overview

Problem

Existing fixing devices in high-speed image forming apparatuses face challenges in properly fixing toner images on recording media due to deformation and wear issues caused by pressure and lubricant ingress, leading to variations in pressure and noise generation.

Innovation Solution

A fixing device comprising a flexible endless belt, a pressing rotary member, a fixed member, a heating member, a seal member, and a reinforcement member, where the heating member has an opening covered by the seal member to prevent foreign substances from entering and the reinforcement member is pressed against the fixed member to reinforce it, ensuring consistent pressure and preventing deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the heating member has a thin thickness to improve heating efficiency, then heating efficiency is improved, but the heating member is deformed by pressure applied at the nip portion

Engineering Contradiction:

Improveheating efficiencyVSAvoidheating member deformation

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The heating member is divided into two functional parts: a thin heating portion (for efficient heat transfer) and a thick reinforcement portion (for structural stability). This segmentation allows each part to optimize its function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different thicknesses are applied to different locations of the heating member. The heating portion has thin thickness for efficient heat conduction, while the reinforcement portion has thick thickness to resist deformation at the nip portion where pressure is applied.

Inventive Principle:

Principle #3Local quality

2Force

If a lubricant is applied between the heating member and the belt to decrease resistance, then resistance is decreased, but the lubricant enters the heating member through the opening and degrades the heater

Engineering Contradiction:

Improveresistance between heating member and beltVSAvoidheater degradation

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

A seal member is introduced as an intermediary between the lubricant and the heater. The seal member prevents the lubricant from reaching the heater while allowing the lubricant to function between the heating member and the belt, thus protecting the heater from degradation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful effect of the lubricant is extracted by preventing it from contacting the heater through the seal member, while retaining the beneficial effect of reduced friction between the heating member and belt.

Inventive Principle:

Principle #2Taking out (Extraction)

3Stress or pressure

If the heating member has an opening to allow pressure application at the nip portion, then pressure application is enabled, but foreign substances enter the heating member causing wear and heater degradation

Engineering Contradiction:

Improvepressure at nip portionVSAvoidforeign substance ingress

Core Design Contradiction:

Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The seal member acts as a mediator that blocks foreign substances (lubricant) from entering the heating member through the opening, while allowing the opening to maintain its function for pressure application and structural flexibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The seal member is implemented as a flexible sealing structure that can accommodate the opening in the heating member while preventing foreign substance ingress, maintaining both pressure transmission and protection functions.

Inventive Principle:

Principle #30Flexible shells and thin films

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 solution effectively prevents deformation of the heating member, maintains consistent pressure, and prevents foreign substances from entering, thereby ensuring reliable fixing of toner images on recording media even at high speeds and reducing wear and noise.

Implementation Method 1

The heating member includes an opening opposing the nip portion so that the heating member faces the inner circumferential surface of the belt at a position other than the nip portion, and is heated by the heater provided inside the heating member

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS8160484B2Fixing device and image forming apparatus incorporating same

Publication Date: 2012.04.17 RICOH CO LTD

AI summary

In a fixing device, a fixed member is fixedly provided inside a loop formed by a belt, and is pressed against a pressing rotary member via the belt to form a nip portion between the pressing rotary member and the belt to nip a recording medium bearing a toner image. A heating member is fixedly, provided inside the loop formed by the belt to heat the belt. The heating member includes an opening opposing the pressing rotary member. A seal member covers the opening in the heating member to prevent a foreign substance from entering the heating member through the opening in the heating member. A reinforcement member is fixedly provided inside the heating member and pressed against the fixed member via the seal member to reinforce the fixed member.