Fixing Roller Replacement Aid for Laser Printer Maintenance

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Solution Overview

Problem

The existing fixing units in image forming apparatuses, such as laser beam printers, face inefficiencies and safety concerns during the replacement of heating rollers due to high temperatures, weight, and instability, leading to prolonged downtime and increased maintenance costs.

Innovation Solution

A fixing roller replacement system that includes a guiding shaft, an assisting unit with latches and supporting roller members, and a protective pipe to facilitate safe and stable handling and positioning of the heating roller, reducing the risk of damage and operator exposure to heat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the heating roller is kept at high temperature to provide sufficient thermal capacity for fixing, then the fixing performance is improved, but the replacement time is increased due to long cooling period

Engineering Contradiction:
Improvefixing performanceVSAvoidreplacement time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The cooling fan is activated before the heating roller needs to be replaced, initiating the cooling process in advance. This preliminary action reduces the cooling time required during replacement operations, allowing the roller to be replaced sooner without compromising the high-temperature fixing performance during normal operation.

Inventive Principle:
Principle #10Preliminary action

2Power

If the heating roller is made heavy with large thermal capacity to support high-speed printing, then the heat supply capability is improved, but the handling stability is worsened during replacement

Engineering Contradiction:
Improveheat supply capabilityVSAvoidhandling stability
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

A replacement aid tool is introduced as an intermediary device to assist in handling the heavy heating roller during replacement. The tool provides mechanical advantage and stability during the replacement process, allowing technicians to safely handle the heavy roller without direct manual contact, thus improving handling stability without compromising the roller's thermal capacity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Manual mechanical handling of the heavy roller is replaced with an automated or assisted mechanical system. The replacement aid tool uses mechanical principles to lift, support, and position the heavy roller, substituting human manual labor with a designed mechanical assistance system that provides better stability and control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Speed

If the heating roller surface is coated with PFA resin for high-speed printing, then the heat supply speed is improved, but the surface protection during replacement is worsened due to heat and handling

Engineering Contradiction:
Improveheat supply speedVSAvoidsurface damage risk
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

A protective covering or sleeve is introduced as an intermediary between the PFA-coated roller surface and the external environment during replacement. This protective layer shields the heat-sensitive PFA coating from direct exposure to handling stresses, heat transfer to surrounding components, and potential damage, while allowing the roller to maintain its high-speed heat supply capability during normal operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Protective measures are taken before the replacement process begins to cushion and protect the PFA coating from potential damage. The protective covering is applied in advance, and handling procedures are designed to minimize stress on the coating, preventing damage before it can occur during the replacement operation.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Adaptability or versatility

If multiple types of heating rollers are incorporated to satisfy different printing needs, then the adaptability is improved, but the replacement complexity is increased

Engineering Contradiction:
Improveprinting capabilityVSAvoidreplacement complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The replacement aid tool is designed with universal functionality that can accommodate different types of heating rollers (PFA-coated, silicone rubber-covered, PFA-tubed). The tool provides standardized mechanical support and handling capabilities for various roller configurations, allowing technicians to replace different roller types using the same assistance mechanism, thus reducing replacement complexity while maintaining adaptability to different printing needs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2290468B1Fixing roller for fixing unit, fixing unit, image forming apparatus, roller replacement aid for fixing unit, and method of replacing fixing roller in fixing unit
Publication Date: 2018.05.23 RICOH CO LTD
  • EP2290468B1 patent drawingFigure 1
  • EP2290468B1 patent drawingFigure 2~4
  • EP2290468B1 patent drawingFigure 5

AI summary

In a fixing unit (12) in which at least one of a heating roller (14) and a pressing roller (15) is provided as a fixing roller and is replaceably supported along the axial direction of the fixing roller, a sliding member (14d) is formed integrally to the inside of the fixing roller, so that the sliding member (14d) slides on the outer circumference of a roller guiding shaft (30) upon replacing the fixing roller.