Developer Roller Position Detection in Image Forming Apparatus

Solution Overview

Problem

Conventional image forming apparatuses lack a mechanism to detect whether the developer roller is in contact with or separated from the photosensitive drum, leading to potential incorrect actions during operation.

Innovation Solution

An image forming apparatus with a movable mechanism for the developer roller that can shift between contact and separated positions, and a detectable member to determine its state, ensuring accurate detection of the roller's position relative to the photosensitive member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a removable processing cartridge with a movable developer roller is used, then the developer roller can be shifted between contact and separated positions, but there is no mechanism to detect the roller's position state

Engineering Contradiction:

Improvedeveloper roller position controlVSAvoidposition state detection

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

A detectable member (such as a flag, protrusion, or reflective element) is introduced as an intermediary between the developer roller position and the detection system. This member is coupled to the movable mechanism and translates the roller's position state into a detectable signal form, enabling reliable detection without directly modifying the roller itself.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical position sensing with a detectable member that can be sensed by optical, magnetic, or capacitive sensors. This substitution allows for non-contact detection and more reliable position state identification compared to purely mechanical sensing methods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If the developer roller is movable between contact and separated positions, then flexible control of developer supply is achieved, but incorrect actions may occur without position detection

Engineering Contradiction:

Improvedeveloper supply controlVSAvoidoperation accuracy

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The detectable member provides feedback about the developer roller's position state to the control system. This feedback loop enables the system to know the current state (contact or separated) and make accurate decisions about subsequent actions, preventing incorrect operations and ensuring reliable developer supply control.

Inventive Principle:

Principle #23Feedback

3Device complexity

If no detection mechanism is provided, then the device structure remains simple, but the risk of incorrect operations increases

Engineering Contradiction:

Improvedetection mechanismVSAvoidoperation correctness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

A detectable member (such as a flag, protrusion, or reflective element) is introduced as an intermediary between the developer roller position and the detection system. This member is coupled to the movable mechanism and translates the roller's position state into a detectable signal form, enabling reliable detection without directly modifying the roller itself.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical position sensing with a detectable member that can be sensed by optical, magnetic, or capacitive sensors. This substitution allows for non-contact detection and more reliable position state identification compared to purely mechanical sensing methods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9274494B2Image forming apparatus

Publication Date: 2016.03.01 BROTHER KOGYO KK

AI summary

An image forming apparatus, including a main body and a cartridge configured to be detachably attached to the main body, is provided. The cartridge includes a photosensitive member configured to carry an image formed in a developer agent thereon, a movable mechanism, and a developer roller configured to supply the developer agent to the photosensitive member. The movable mechanism is configured to shift between a first state, in which the developer roller is placed in a contact position to contact the photosensitive member, and a second state, in which the developer roller is placed in a separated position to be separated from the photosensitive member. The main body includes a detectable member configured to detect a state of the movable mechanism between the first state and the second state.