Developing Roller Contact Pressure Control

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Solution Overview

Problem

Conventional image forming apparatuses experience rapid wear of the photosensitive drum due to excessive friction and pressure from the developing unit, leading to shortened drum life and image quality issues.

Innovation Solution

An image forming apparatus with a top-mounted photosensitive drum and a resilient member, such as a compression spring, is used to counteract the weight of the developing cartridge, maintaining steady contact pressure and reducing wear on the photosensitive drum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the developing roller presses against the photosensitive drum at high pressure to maintain contact when toner level is low, then the contact between developing roller and photosensitive drum is maintained, but the photosensitive drum deteriorates rapidly and image quality deteriorates

Engineering Contradiction:

Improvecontact maintenanceVSAvoidphotosensitive drum life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The developing unit is designed to rotate about a rotation axis, enabling dynamic adjustment of the developing roller's position relative to the photosensitive drum. This rotational capability allows the system to adapt the contact pressure dynamically based on toner level, maintaining reliable contact when needed while reducing wear when possible

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the contact pressure parameter dynamically. When toner level is high, the developing unit rotates to reduce contact pressure and minimize wear. When toner level is low, it rotates to increase contact pressure and maintain reliable toner transfer, thus optimizing both drum life and contact reliability under different operating conditions

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If the developing unit contains a toner supplier, then the developing unit can function properly, but the weight and lateral locking force of the developing unit cause excessive friction and wear on the photosensitive drum

Engineering Contradiction:

Improvedeveloping unit functionVSAvoidfriction and wear on photosensitive drum

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The developing unit is designed to rotate freely about a rotation axis, allowing the weight of the toner supplier to be counterbalanced by gravitational force acting on the rotating mechanism. This reduces the lateral locking force and friction on the photosensitive drum while maintaining the developing unit's functional weight for proper operation

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Stability of the object's composition

If a lock device pushes the developing unit towards the photosensitive drum, then the developing unit is secured in position, but the increased pressure causes expedited deterioration of the photosensitive drum

Engineering Contradiction:

Improvedeveloping unit positioningVSAvoidphotosensitive drum life

Core Design Contradiction:

Stability of the object's compositionVSDuration of action of stationary object

Solution Approach 1:

Instead of a static lock device that continuously pushes the developing unit against the photosensitive drum, the system uses a dynamic rotational mechanism about a rotation axis. The developing unit can be positioned and locked at different angular positions, allowing stable positioning without continuous high pressure on the photosensitive drum surface

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

The solution ensures a stable and tight contact between the developing roller and the photosensitive drum, significantly reducing wear and enhancing the drum's endurance.

Implementation Method 1

The resilient member, disposed between the developing tank and the case, provides a restoring force for counteracting a weight of the developing tank and urging the developing roller towards the photosensitive drum

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8538292B2Image forming apparatus with supporting member set and force-exerting member set interacting with each other

Publication Date: 2013.09.17 AVISION

AI summary

An image forming apparatus includes a case, a photosensitive drum, a developing cartridge, a supporting member set, a force-exerting member set and a resilient member. The photosensitive drum forms a toner image. The developing cartridge, movably disposed within the case, includes a developing tank and a developing roller. The developing roller, mounted on the developing tank and positioned opposite the photosensitive drum, transfers toners to the photosensitive drum. The supporting member set is disposed on an inner wall of the case. The force-exerting member set, disposed on an outer wall of the developing tank, interacts with the supporting member set to maintain steady contact pressure between the developing roller and the photosensitive drum. The resilient member, disposed between the developing tank and the case, provides a restoring force for counteracting a weight of the developing tank and urging the developing roller towards the photosensitive drum.