Photosensitive Drum Abnormality Detection via Transfer Roller Resistance

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The image forming apparatus experiences a drop in voltage applied to the charging roller due to thinning of the photosensitive layer of the image bearing member, leading to white background fogging and other issues, as the layer wears away from contact with the charging roller, making it difficult to accurately determine abnormalities in the photosensitive drum.

Innovation Solution

The apparatus detects a resistance detection voltage to determine abnormalities in the photosensitive drum, correlating it with the photosensitive surface voltage to assess the thinning of the layer and adjust voltages accordingly, using a control unit to monitor and adjust the current between the primary transfer roller and the photosensitive drum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a charging roller system is used to charge the image bearing member, then charging function is achieved, but the photosensitive layer is worn away and thinned

Engineering Contradiction:

Improvecharging functionVSAvoidphotosensitive layer thickness

Core Design Contradiction:

Ease of operationVSLoss of substance

Solution Approach 1:

The patent replaces the mechanical contact-based charging roller system with a non-contact electrostatic charging system. The charger roller applies electric fields to charge the photosensitive drum surface without physical contact, thereby eliminating mechanical wear and thinning of the photosensitive layer while maintaining the charging function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If the photosensitive layer is thinned due to wear, then leakage current increases, but voltage applied to the charging roller drops

Engineering Contradiction:

Improveleakage current controlVSAvoidvoltage applied to charging roller

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

By replacing the mechanical charging roller contact system with a non-contact electrostatic charging system, the patent eliminates the leakage current path through the photosensitive layer that occurs with mechanical contact. This prevents voltage drops and maintains stable power delivery to the charging system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an electrostatic field as an intermediary between the charger roller and the photosensitive drum surface. This field-mediated charging process avoids direct contact and the associated leakage current issues, maintaining both voltage stability and reliable charging function.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Power

If voltage applied to the charging roller drops, then surface potential decreases, but white background fogging occurs

Engineering Contradiction:

Improvevoltage applied to charging rollerVSAvoidwhite background fogging

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The non-contact electrostatic charging system maintains stable voltage levels by eliminating the leakage current path, thereby preserving surface potential on the photosensitive drum and preventing white background fogging that occurs when voltage drops.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent incorporates voltage detection and control mechanisms that monitor the voltage applied to the charger roller and adjust the system to maintain optimal surface potential, preventing the development of white background fogging defects.

Inventive Principle:

Principle #23Feedback

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 method allows for accurate determination of abnormalities in the photosensitive drum, preventing voltage drops and reducing issues like white background fogging, while maintaining optimal surface potential and electrical resistance.

Implementation Method 1

a charging roller configured to charge the image bearing member

Methodology Applied

Scientific EffectElectrical charge transfer: Conduction (electrical)

Implementation Method 2

detecting a resistance detection voltage of the transfer belt as a voltage for detecting that there is an abnormality in the image bearing member

Methodology Applied

Scientific EffectElectrical resistance measurement: Electrical Resistance

Data Source

PatentUS20240310769A1Image forming apparatus abnormality detection

Publication Date: 2024.09.19 TOSHIBA TEC KK

AI summary

According to one embodiment, an image forming apparatus includes an image bearing member, a charging roller, an exposure unit, a developing device, a transfer roller, and a control unit. The charging roller charges the image bearing member. The exposure unit forms an electrostatic latent image on the surface of the image bearing member. The developing device develops the electrostatic latent image formed on the surface of the image bearing member into a toner image. The transfer roller transfers the toner image from the image bearing member. The control unit detects a resistance detection voltage of the transfer roller as a voltage for detecting that there is an abnormality in the image bearing member.