Anodized Nip Former for Image Fixing Torque Control

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Solution Overview

Problem

Existing nip formers in image forming apparatuses face challenges in maintaining high-speed image formation and extended product life while ensuring high-quality image output, as they often suffer from temperature fluctuations, lubricant shortages, and mechanical stress, leading to degraded performance and increased torque.

Innovation Solution

A nip former with an anodic oxidation coating on an aluminum base, where the coating is sealed to maintain even thickness and prevent lubricant shortages, is used to form a fixing nip between an endless belt and a pressure rotator, optimizing sliding and thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the nip former is made of aluminum with increased thickness to improve mechanical strength, then the mechanical strength is improved, but the weight and size increase, and high-speed image formation cannot be achieved

Engineering Contradiction:
Improvemechanical strengthVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The nip former uses a composite structure combining aluminum base material with an anodic oxidation coating layer. This composite approach provides both the light weight and thermal conductivity of aluminum while the coating layer supplies the required surface hardness and wear resistance, eliminating the need to increase thickness for strength

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the surface properties of aluminum through anodic oxidation, transforming the soft aluminum surface into a hard coating layer. This parameter change in surface hardness allows thin aluminum nip formers to achieve the mechanical strength and wear resistance previously requiring much thicker sections

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the anodic oxidation coating is not sealed, then the coating can be applied, but the coating absorbs lubricant excessively causing lubricant shortage and degraded performance

Engineering Contradiction:
Improvecoating applicationVSAvoidperformance stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention applies a sealing treatment that changes the physical state of the anodic oxidation coating from porous to non-porous. This parameter change in porosity prevents excessive lubricant absorption while maintaining the coating's hardness and wear resistance properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention converts the potentially harmful porous structure of the anodic oxidation coating into a beneficial sealed structure. The sealing process transforms the coating from a lubricant-absorbing defect into a controlled, non-porous surface that maintains optimal lubricant film thickness for reliable performance

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

3Productivity

If the heater heats the endless belt to high temperature for high-speed printing, then the printing speed is improved, but the lubricant evaporates or degrades causing increased torque and degraded sliding performance

Engineering Contradiction:
Improveprinting speedVSAvoidsliding performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The sealed anodic oxidation coating changes the thermal and chemical environment at the nip former surface, creating a more stable interface that protects the lubricant from high-temperature degradation and evaporation, maintaining sliding performance even during high-speed printing operations

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a durable, heat-resistant anodic oxidation coating that replaces the need for frequent lubricant replenishment. The coating acts as a protective barrier that maintains its function throughout the product lifecycle, eliminating the 'short-living' nature of the lubricant alone

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Temperature

If a lamp heater is used to heat the endless belt in an increased span, then the temperature stability is improved, but the energy consumption increases

Engineering Contradiction:
Improvetemperature stabilityVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The invention applies heating locally at the nip region rather than heating the entire endless belt span. The anodic oxidation coating on the nip former facilitates efficient heat transfer locally, achieving temperature stability only where needed for image fixing, thereby reducing overall energy consumption

Inventive Principle:
Principle #3Local quality

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 enhances the sliding performance of the endless belt, downsizes and lightens the fixing device, and achieves high-quality image formation over a prolonged period, while maintaining mechanical strength and thermal efficiency.

Implementation Method 1

The nip former is made of aluminum that has an enhanced thermal conductivity

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The anodic oxidation coating is treated with sealing. The sealing prevents a lubricant from being absorbed into the anodic oxidation coating

Methodology Applied
Scientific EffectAbsorption prevention: Absorption (physical)

Implementation Method 3

The endless belt slides over the nip former via a lubricant applied between the endless belt and the nip former

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP4155830B1Nip former, fixing device, and image forming apparatus
Publication Date: 2024.03.06 RICOH CO LTD
  • EP4155830B1 patent drawingFigure 1
  • EP4155830B1 patent drawingFigure 2~3
  • EP4155830B1 patent drawingFigure 4

AI summary

A nip former (27; 27S) that forms a nip (N) between an endless belt (21; 121) and a pressure rotator (22) includes a base (27a) that is made of aluminum and has a nip forming face (27c) disposed opposite the nip (N). An anodic oxidation coating (27b; 27bS) is treated with sealing and coats at least the nip forming face (27c). The anodic oxidation coating (27b; 27bS) has a thickness that is not smaller than 22 µm and is not greater than 45 µm and a variation in thickness that is not greater than 20 percent. The base (27a) and the anodic oxidation coating (27b; 27bS) define a nip forming portion (27d; 27dS) that is disposed opposite the nip (N). The nip forming portion (27d; 27dS) has a thickness that is not smaller than 0.40 mm and is not greater than 1.20 mm.