Fixing Device Lubricant Recesses Suppress Outflow

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Solution Overview

Problem

Conventional fixing devices in image forming apparatuses face issues with lubricant leakage and evaporation, leading to decreased sliding performance over time, as the viscosity of lubricants decreases with heating, causing increased friction and wear.

Innovation Solution

A lubricant holding member with alternating recesses and slits is used, applying a first lubricant of low viscosity to the entire inner surface and a second lubricant of higher viscosity only in recesses, which reduces lubricant outflow and maintains low friction without increasing viscous resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lubricant is applied to the inner peripheral surface of the fixing belt to reduce frictional resistance, then the sliding performance is improved, but the lubricant leaks out from the edges or evaporates with heating, causing the sliding performance to deteriorate over time

Engineering Contradiction:
Improvesliding performanceVSAvoidlubricant
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The pressing pad is provided with a lubricant supply member that supplies lubricant to the inner peripheral surface of the fixing belt in advance before the lubricant is depleted. This preliminary action ensures continuous lubrication and prevents the deterioration of sliding performance over time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The lubricant supply member is integrated into the pressing pad, which automatically supplies lubricant to the fixing belt during operation. The system serves itself by using the existing pressing mechanism to deliver the lubricant without requiring external intervention.

Inventive Principle:
Principle #25Self-service

2Loss of substance

If a high viscosity lubricant is used to suppress lubricant outflow, then the loss of lubricant is reduced, but the viscous resistance and frictional resistance increase

Engineering Contradiction:
ImprovelubricantVSAvoidsliding performance
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The lubricant supply member supplies lubricant locally to the specific region where it is needed on the inner peripheral surface of the fixing belt. This localized application ensures adequate lubrication without requiring excessive lubricant viscosity, thereby maintaining low frictional resistance.

Inventive Principle:
Principle #3Local quality

3Productivity

If the operation time of the fixing device is extended, then the productivity is improved, but the initially applied lubricant becomes insufficient and sliding performance deteriorates

Engineering Contradiction:
Improveoperation timeVSAvoidsliding performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The lubricant supply member ensures continuous supply of lubricant to the fixing belt throughout the extended operation time. This continuous action maintains the sliding performance and prevents deterioration even during prolonged operation periods, thereby supporting higher productivity.

Inventive Principle:
Principle #20Continuity of useful 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 solution effectively suppresses lubricant outflow and wear, maintaining the sliding performance and reducing friction between the fixing belt and pressing pad for an extended period, ensuring continuous lubrication and high throughput in image forming processes.

Implementation Method 1

a heater provided for heating the rotatable heated body

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

a lubricant, such as silicone oil, is typically applied to the inner peripheral surface of the fixing belt. This reduces the frictional resistance of the fixing belt with respect to pressing pad

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 3

it is known that such a lubricant (e.g., the silicone oil) may leak out from the edges of the fixing belt, or also may eventually evaporate with heating/use

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3789829B1Fixing device and image forming apparatus
Publication Date: 2022.06.29 TOSHIBA TEC KK
  • EP3789829B1 patent drawingFigure 1
  • EP3789829B1 patent drawingFigure 2
  • EP3789829B1 patent drawingFigure 3

AI summary

According to an embodiment, a fixing device used for fixing a toner image to a sheet in a printing process includes a rotatable heated body having an inner facing surface and an outer facing surface. A heater for heating the rotatable heated body has a length corresponding to the length of the heated body. A pressing member contacts the inner facing surface of the rotatable heated body at a first position. A pressing roller presses against the outer facing surface of the rotatable heated body at a position corresponding to the pressing member. A lubricant holding member has a lubricating surface that contacts the inner facing surface of the rotatable heated body at a second position. The lubricant holding member has a plurality of recesses in its lubricating surface. The recesses are spaced from each other along the length of the lubricant holding member.