Fixing Device Air Nozzle Configuration for Sheet Separation

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Solution Overview

Problem

Conventional fixing devices for image forming apparatuses require high-power compressors to release recording sheets from fixing rollers, leading to large apparatus sizes and potential scratches on the rollers, while maintaining efficient separation is challenging, especially with thin papers and color images.

Innovation Solution

A fixing device with a first air nozzle blowing high-speed air for a short period and a second air nozzle blowing continuous air at lower speed but higher flow rate, positioned in parallel with the rotational axis of the fixing member, to separate the recording sheet efficiently without the need for high-power compressors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a releasing claw is used to separate the recording sheet from the fixing roller, then separation efficiency is improved, but scratches are caused on the fixing roller surface

Engineering Contradiction:

Improveseparation efficiencyVSAvoidscratches on fixing roller

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical contact method (releasing claw) with a pneumatic method (air blowing device). Air is blown through nozzles positioned near the nip portion to create a air cushion that lifts and separates the recording sheet from the fixing roller surface, eliminating direct mechanical contact and preventing scratches while maintaining separation efficiency

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention uses compressed air delivered through nozzles to achieve sheet separation. The air flow creates a pneumatic cushion between the recording sheet and the fixing roller, enabling non-contact separation that avoids surface damage to the fixing roller while effectively preventing sheet adhesion

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Productivity

If high-power compressors are used to blow air for sheet separation, then separation efficiency is improved, but apparatus size and power consumption increase

Engineering Contradiction:

Improveseparation efficiencyVSAvoidapparatus size

Core Design Contradiction:

ProductivityVSWeight of stationary object

Solution Approach 1:

The patent applies air blowing locally only at the critical separation zone near the nip portion exit, rather than using high-power compressors to blow air throughout the entire system. Multiple nozzles are positioned strategically to target the exact area where sheet separation is needed, reducing overall air consumption and allowing the use of smaller compressors

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The air blowing function is segmented into multiple nozzles positioned at different locations near the nip portion. This segmentation allows each nozzle to handle a specific zone, improving separation efficiency through distributed air flow while reducing the total power requirement compared to a single high-power compressor system

Inventive Principle:

Principle #1Segmentation

3Productivity

If high-power compressors are used to blow air for sheet separation, then separation efficiency is improved, but power consumption increases

Engineering Contradiction:

Improveseparation efficiencyVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by stationary object

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention uses multiple nozzles providing moderate air flow to specific zones rather than one high-power compressor providing excessive air flow to the entire system. This partial action approach achieves sufficient separation efficiency while significantly reducing power consumption

Inventive Principle:

Principle #16Partial or excessive action

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 reduces the size and power consumption of the apparatus while ensuring effective separation of recording sheets from the fixing device, preventing scratches on the rollers and maintaining high releasing efficiency even with thin papers and color images.

Implementation Method 1

a first air nozzle 201 that blows air against a neighborhood of a leading edge of the recording material

Methodology Applied

Scientific EffectAir flow:

Implementation Method 2

a second air nozzle 301 that blows air against the recording material that has passed through the nip portion

Methodology Applied

Scientific EffectAir flow:

Data Source

PatentUS8634752B2Fixing device that fixes a toner image on a recording material

Publication Date: 2014.01.21 KONICA MINOLTA INC

AI summary

A fixing device fixing a toner image on a recording material includes a first blowing section that blows air against a leading edge of the recording material that has passed through a nip portion formed by a heated fixing member and a pressing member kept in pressure contact with the fixing member, and a second blowing section that blows air against the recording material that has passed through the nip portion, wherein an air speed of air blown out from a first blowing outlet is higher than that of air blown out from a second blowing outlet, wherein an air flow amount from the first blowing outlet is less than that from the second blowing outlet, and wherein the first and second blowing outlets are arranged at a same positional height next to one another along a rotational axis of the fixing roller.