Fixing Device Heater Holder Retraction Portion

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Solution Overview

Problem

In existing fixing devices, the heater's length is determined by the largest paper size, leading to inefficiencies when smaller papers are processed, as the outer portions of the heater do not absorb heat, potentially causing the holder to overheat and deform.

Innovation Solution

The fixing device incorporates a holder with a support portion and a retraction portion, where the support portion contacts the heater to support it, and the retraction portion, with a smaller contact area or no contact, is positioned to avoid heat transfer from the outer, non-absorbing regions of the heater.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the heater length is determined according to the largest paper size, then the heater can heat the entire paper width, but the outer portions of the heater do not transfer heat to smaller papers causing holder overheating

Engineering Contradiction:

Improveholder temperatureVSAvoidholder structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The holder is divided into two distinct functional zones: a support portion that contacts the heater to provide structural support, and a retraction portion that avoids contact with the heater's outer high-temperature regions. This segmentation allows the holder to perform its support function while preventing heat transfer to the holder body, resolving the contradiction between temperature control and structural simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the holder are given different thermal properties and contact characteristics. The support portion has high thermal contact with the heater for structural stability, while the retraction portion has reduced or no thermal contact to avoid overheating. This local differentiation of contact quality allows the holder to maintain structural integrity while preventing temperature rise in critical areas.

Inventive Principle:

Principle #3Local quality

2Temperature

If external coolers are added to cool the fixing belt and press roller, then the holder temperature can be reduced, but the device complexity and cost increase

Engineering Contradiction:

Improveholder temperatureVSAvoidcooling system

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The harmful thermal contact between the holder and the heater's outer portions is extracted and removed by designing the retraction portion to avoid contact. This eliminates the heat transfer path without requiring any active cooling systems, thereby resolving the contradiction between temperature control and device simplicity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The heater's outer portions that were previously considered wasted space are now utilized as thermal isolation zones. By positioning the retraction portion of the holder to align with these outer portions, the design converts the potentially harmful heat-generating areas into beneficial thermal barriers that protect the holder from overheating.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Temperature

If paper passing speed is lowered or paper sheet interval is widened, then the holder temperature can be controlled, but the productivity of the image forming apparatus decreases

Engineering Contradiction:

Improveholder temperatureVSAvoidpaper passing speed

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The holder structure is segmented into support and retraction portions that differentially manage thermal contact. This allows continuous high-speed paper passing while preventing heat accumulation in the holder, resolving the contradiction between temperature control and productivity by eliminating the need to slow down the paper feed rate.

Inventive Principle:

Principle #1Segmentation

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 prevents temperature rises in the holder while maintaining the device's performance and avoiding an increase in the number of parts, thus ensuring efficient heat transfer and preventing thermal deformation of the holder.

Implementation Method 1

a heater including a heat generating resistor layer provided on a substrate may be used

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The heat of the heat generating resistor layer is absorbed by the paper through the fixing belt during continuous paper passing

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS12306563B2Fixing device with a heater holder having a retraction portion

Publication Date: 2025.05.20 TOSHIBA TEC KK

AI summary

According to one embodiment, a fixing device includes a belt, a heater, and a holder. The holder has a plurality of support portions that contact an end of the first heating region and an end of the second heating region along the direction perpendicular to the transport direction, and a plurality of non-contacting portions that do not contact the end of the first heating region and the end of the second heating region between the plurality of support portions, the end of the second heating region contacts one of the plurality of support portions at a side in the direction perpendicular to the transport direction, and the end of the second heating region faces to one of the plurality of non-contacting portions at the other side in the direction perpendicular to the transport direction.