Fixing Device Separator Contact Mechanism for Belt Protection

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Solution Overview

Problem

Existing fixing devices in electrophotographic image forming apparatuses face challenges in maintaining a stable separation function due to fluctuations in the rotator surface, leading to potential damage from the separation plate being pushed into the fixing belt.

Innovation Solution

The proposed fixing device includes a separator with contact portions that contact the nip formation pad via the fixing belt, preventing direct contact with the fixing belt and maintaining a constant clearance, thereby preventing damage and ensuring stable separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the separator directly contacts the fixing belt to maintain stable separation, then separation reliability improves, but the separator may be pushed into the fixing belt causing damage

Engineering Contradiction:

Improveseparation reliabilityVSAvoiddamage to fixing belt

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a contact portion that acts as an intermediary between the separator and the fixing belt. This contact portion contacts the nip formation pad through the fixing belt, rather than the separator directly contacting the fixing belt. This intermediary structure maintains stable separation while preventing the separator from being pushed into the fixing belt, thus resolving the contradiction between separation reliability and prevention of damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the separator maintains constant clearance from the fixing belt, then separation stability improves, but direct contact occurs when surface fluctuations happen

Engineering Contradiction:

Improveseparation stabilityVSAvoiddirect contact damage

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The contact portion serves as a mediator that maintains constant clearance from the nip formation pad through indirect contact. When the fixing belt surface fluctuates, the contact portion contacts the nip formation pad via the fixing belt, preventing direct contact between the separator and fixing belt while maintaining separation stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The structure provides beforehand cushioning by allowing the contact portion to contact the nip formation pad through the fixing belt before any potential damage can occur. This preemptive contact mechanism absorbs surface fluctuations and prevents harmful direct contact between the separator and fixing belt.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of operation

If the separator contacts the fixing belt directly, then separation function is maintained, but mechanical damage and image unevenness occur

Engineering Contradiction:

Improveseparation functionVSAvoidimage unevenness and mechanical damage

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The contact portion acts as an intermediary structure that enables the separation function to be maintained while preventing mechanical damage and image unevenness. By contacting the nip formation pad through the fixing belt rather than directly contacting the fixing belt, the separator achieves its separation purpose without causing harmful effects.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 ensures the separation plate does not push into the fixing belt, maintaining the belt's integrity and stability, and preventing image unevenness and mechanical damage.

Implementation Method 1

The heater includes a resistive heat generator to heat the first rotator

Methodology Applied

Scientific EffectResistive heating: Joule Heating

Data Source

PatentUS12092978B2Fixing device and image forming apparatus incorporating the same

Publication Date: 2024.09.17 RICOH CO LTD

AI summary

A fixing device includes a first rotator, a second rotator, a heater, a nip formation pad, and a separator. The second rotator contacts an outer circumferential surface of the first rotator to form a nip between the first rotator and the second rotator. The heater includes a resistive heat generator to heat the first rotator. The nip formation pad contacts an inner circumferential surface of the first rotator to form the nip. The separator separates a recording medium passing through the nip from the first rotator. The separator includes a separating surface and a contact. The separating surface is separated from the outer circumferential surface of the first rotator and separates the recording medium from the first rotator. The contact contacts the outer circumferential surface of the first rotator at a position where the first rotator is pinchable between the contact and the nip formation pad.