Photosensitive Drum Speed Control via Toner Lubrication

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Solution Overview

Problem

Existing image forming apparatuses face challenges in reducing deterioration caused by abrasion of photosensitive drums and intermediate transfer members when changing image forming speeds, and in minimizing the time required for such speed changes.

Innovation Solution

The apparatus controls the abutment and separation of development rollers and photosensitive drums, and adjusts the speeds of photosensitive drums and intermediate transfer members while providing toner between them to reduce abrasion and expedite speed changes, using mechanisms like stepping motors and cam gears for precise control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the speed of photosensitive drum and intermediate transfer member is controlled using encoder to reduce speed difference, then image deterioration caused by abrasion is reduced, but it is difficult to completely eliminate circumferential speed difference leading to slight deterioration

Engineering Contradiction:

Improveimage qualityVSAvoidabrasion of photosensitive drum and intermediate transfer member

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces toner as an intermediary substance between the photosensitive drum and intermediate transfer member. By controlling the developer carrier to convey toner during speed changes, a lubricating layer is formed that mediates the interaction between the two members, reducing direct friction and abrasion while allowing speed differences to occur without significant deterioration.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical state and distribution of toner during speed transitions. By adjusting the conveyance of toner from the developer carrier to the photosensitive drum, the friction characteristics between the photosensitive drum and intermediate transfer member are dynamically modified, enabling smooth speed changes with minimal abrasion.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If the photosensitive drum and intermediate transfer member are stopped and then driven again at new desired speed to suppress circumferential speed difference, then abrasion is reduced, but the time required to change image forming speed increases

Engineering Contradiction:

Improveabrasion of photosensitive drum and intermediate transfer memberVSAvoidtime to change image forming speed

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent maintains continuous operation of the photosensitive drum and intermediate transfer member during speed changes by introducing toner as a lubricant. This eliminates the need to stop the members, allowing continuous image formation while reducing abrasion through the toner-mediated friction reduction, thus maintaining productivity without sacrificing component protection.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent converts the potentially harmful effect of speed differences and friction into a beneficial outcome by using toner as a lubricating medium. The friction that would normally cause abrasion is transformed into a controlled lubricating effect, allowing speed transitions without stopping while actually reducing wear through the intermediary toner layer.

Inventive Principle:

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

3Object-affected harmful factors

If the friction between cleaning member and photosensitive drum is reduced to prevent blade sounding, then cleaning effectiveness may be compromised, but blade sounding is prevented

Engineering Contradiction:

Improveblade soundingVSAvoidcleaning effectiveness

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent dynamically adjusts the friction characteristics between the cleaning blade and photosensitive drum by controlling toner presence. During low-speed operations, toner is maintained on the drum surface to reduce friction and prevent blade sounding. The system selectively modifies friction parameters based on operating conditions, preventing noise while preserving cleaning functionality when needed.

Inventive Principle:

Principle #35Parameter changes

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 approach effectively reduces the deterioration of photosensitive drums and intermediate transfer members during speed changes and shortens the time needed to change image forming speeds, maintaining image quality and extending the life of the components.

Implementation Method 1

control so that a speed change is executed in a state where toner is interposed between the photosensitive drum and the intermediate transfer member... reduces the deterioration caused by abrasion of the photosensitive drum and the intermediate transfer member

Methodology Applied

Scientific EffectFriction reduction through toner lubrication: Lubrication

Data Source

PatentEP2544051B1Image forming apparatus

Publication Date: 2020.12.30 CANON KK

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AI summary

There is provided an image forming apparatus in which an image forming speed is changed in a state where toner is provided between a photosensitive drum (1) and an intermediate transfer member (8). Therefore, even if a speed difference between the photosensitive drum and the intermediate transfer member is generated, a drive torque can be suppressed, and deterioration caused by abrasion of the photosensitive drum and the intermediate transfer member can be reduced.