Transfer Belt Electrode Member for Potential Regulation

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Solution Overview

Problem

In image forming apparatuses of the transfer belt type, unstable electric potentials between the intermediary transfer belt and the transfer belt lead to electric discharge and toner scattering at the secondary transfer portion, affecting image quality by causing white spots and blurring of lines or characters.

Innovation Solution

The introduction of sheet-like electrode members on the inner surfaces of the transfer belt and intermediary transfer belt upstream of the secondary transfer portion helps regulate the surface potentials, preventing abnormal electric discharges by increasing the electrostatic capacity and stabilizing the potential difference between the belts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the recording material is electrostatically attracted to the transfer belt on the upstream side of the secondary transfer portion, then the recording material can be separated easily on the downstream side, but electric discharge and toner scattering occur at the secondary transfer portion

Engineering Contradiction:
Improveseparation of recording materialVSAvoidelectric discharge and toner scattering
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A potential regulating plate is introduced as an intermediary component between the transfer belt and the recording material. This plate regulates the electric potential of the recording material, preventing excessive potential differences that cause electric discharge and toner scattering, while still allowing effective electrostatic attraction for separation downstream

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The electric potential parameters of the recording material are actively regulated and controlled. By adjusting and maintaining the potential within an appropriate range through the potential regulating plate, the system prevents harmful electric discharge while preserving the necessary electrostatic attraction for easy separation

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the electric potential is allowed to fluctuate freely on the transfer belt, then the system operates with simple structure, but the potential unstably fluctuates causing image quality degradation

Engineering Contradiction:
Improvestructure simplicityVSAvoidpotential stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The potential regulating plate is designed to automatically regulate the electric potential of the recording material through its own electrical characteristics. The plate self-adjusts to maintain stable potential without requiring external control systems, preserving structural simplicity while ensuring reliable potential stability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The potential regulating plate creates equipotential conditions on the recording material surface by conducting excess charge to ground or redistributing charge uniformly. This ensures stable potential distribution across the recording material, preventing fluctuations that would degrade image quality

Inventive Principle:
Principle #12Equipotentiality

3Productivity

If the potential difference between the intermediary transfer belt and transfer belt is large, then the toner image transfer is effective, but electric discharge occurs causing white spots and blurring

Engineering Contradiction:
Improvetoner image transfer efficiencyVSAvoidelectric discharge causing image defects
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The potential regulation is applied locally at critical positions where electric discharge is most likely to occur. The potential regulating plate is positioned to specifically control the potential of the recording material at the upstream side of the secondary transfer portion, maintaining effective potential difference for transfer while preventing discharge at vulnerable locations

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The potential regulating plate applies preliminary anti-action by pre-regulating the electric potential of the recording material before it reaches the secondary transfer portion. This preventive measure counteracts the tendency toward excessive potential difference, ensuring that while sufficient potential exists for effective transfer, harmful discharge is prevented in advance

Inventive Principle:
Principle #9Preliminary anti-action

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 solution effectively reduces toner scattering and electric discharge, resulting in improved image quality by maintaining stable potentials and preventing disturbances to the toner image during the transfer process.

Implementation Method 1

an attraction portion for electrostatically attracting the recording material to the transfer belt

Methodology Applied
Scientific EffectElectrostatic attraction: Electrostatics

Implementation Method 2

The introduction of sheet-like electrode members on the inner surfaces of the transfer belt and intermediary transfer belt upstream of the secondary transfer portion helps regulate the surface potentials, preventing abnormal electric discharges by increasing the electrostatic capacity and stabilizing the potential difference between the belts.

Methodology Applied
Scientific EffectElectrostatic capacity: Capacitance

Data Source

PatentEP2325702A1Image forming apparatus
Publication Date: 2011.05.25 CANON KK
  • EP2325702A1 patent drawingFigure 1
  • EP2325702A1 patent drawingFigure 2
  • EP2325702A1 patent drawingFigure 3(A)~3(B)

AI summary

An image forming apparatus includes an image bearing member; an image forming portion for forming a toner image on the image bearing member; an intermediary transfer belt for carrying the toner image transferred from the image bearing member; a transfer belt for carrying and conveying a recording material; an attraction portion for electrostatically attracting the recording material to the transfer belt; a transfer portion for transferring the toner image from the intermediary transfer belt onto the recording material attracted to the transfer belt; and an electrode member, disposed downstream of the attraction portion and upstream of the transfer portion with respect to a movement direction of the transfer belt, being contacted to an inner surface of the transfer belt.