Fixing Device Separator Dynamics for Wear Reduction

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Solution Overview

Problem

Existing fixing devices in image forming apparatuses face issues with separator wear and uneven toner image quality due to constant contact with the fixing member, leading to increased manufacturing costs and potential jamming during warm-up phases, as multiple solenoids are required to control multiple separators, which can result in improper separation of the recording medium.

Innovation Solution

A fixing device with a single solenoid driving multiple separators, which are designed to contact and separate independently from the fixing roller, using a releasing member and biasing members to maintain proper contact and reduce wear, ensuring simultaneous and precise separation even with varying dimensions or roller vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separator contacts the fixing member continuously to prevent recording medium adhesion, then the recording medium can be properly separated, but the fixing member surface experiences wear over time

Engineering Contradiction:
Improverecording medium separationVSAvoidfixing member wear
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The separator is designed to dynamically change its contact state with the fixing member based on operational requirements. During normal operation, the separator maintains contact to prevent adhesion. During warm-up phases or when no recording medium is present, the separator separates from the fixing member to reduce wear. This dynamic adjustment is achieved through a solenoid-driven mechanism that can position the separator in different states.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The separator operates with periodic contact and separation cycles. It contacts the fixing member when recording medium is being processed and separates when the fixing member is warming up or idle. This periodic action pattern allows the separator to perform its separation function when needed while minimizing wear during warm-up phases.

Inventive Principle:
Principle #19Periodic action

2Ease of operation

If multiple solenoids are provided to control multiple separators, then each separator can be controlled independently, but the device size and manufacturing cost increase

Engineering Contradiction:
Improveseparator control precisionVSAvoidnumber of solenoids
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

Multiple separators are combined into a single group that is controlled by one solenoid. The solenoid drives a releasing member that simultaneously acts on multiple separators through a common biasing mechanism. This merging approach maintains the ability to control separator positioning while significantly reducing the number of solenoids required from multiple to single.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single solenoid is designed to perform multiple functions by controlling multiple separators simultaneously. Through the releasing member and biasing members, one solenoid can position multiple separators in contact or separation states as needed, making the solenoid system multi-functional and eliminating the need for separate solenoids for each separator.

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

3Reliability

If separators are kept in contact with the fixing member, then recording medium separation is ensured, but wear during warm-up phases increases

Engineering Contradiction:
Improverecording medium separationVSAvoidwarm-up time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The separator system dynamically adjusts its contact state based on whether the fixing member is in warm-up phase or operational phase. During warm-up, the separator separates from the fixing member to avoid unnecessary wear. When operational, the separator contacts the fixing member to ensure proper recording medium separation. This dynamic behavior is controlled by the solenoid responding to operational signals.

Inventive Principle:
Principle #15Dynamics

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 wear on the fixing member, maintains image quality, and decreases manufacturing costs by using a single solenoid to control multiple separators, ensuring reliable and precise separation of the recording medium, even during warm-up phases.

Implementation Method 1

a solenoid (30) serving as a driver for driving the releasing member (27)

Methodology Applied
Scientific EffectSolenoid: Solenoid

Implementation Method 2

A releasing member (27) driven by a single solenoid (30) contacts and separates from a plurality of separators (23)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2284624B1Fixing Device and Image Forming Apparatus Incorporating Same
Publication Date: 2020.02.26 RICOH CO LTD
  • EP2284624B1 patent drawingFigure 1
  • EP2284624B1 patent drawingFigure 2
  • EP2284624B1 patent drawingFigure 3

AI summary

In a fixing device (20; 20'), a fixing member (21) contacts an opposing member (22) to form a nip (N) therebetween through which a recording medium bearing a toner image passes. A plurality of separators (23) provided downstream from the nip (N) in a recording medium conveyance direction contacts the fixing member (21) to separate the recording medium having passed between the fixing member (21) and the opposing member (22) from the fixing member (21). A plurality of contact-direction biasing members (26) biases the separators (23) to cause the separators (23) to contact the fixing member (21). A releasing member (27) contacts the separators (23) to cause the separators (23) to separate from the fixing member (21). A driver (30) separates the releasing member (27) from the separators (23) to cause the separators (23) to contact the fixing member (21).