Reverse Bias Voltage Control for Toner Adhesion Prevention

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Solution Overview

Problem

During the decoloring process in image forming apparatuses, the high chargeability of paper with fixed toner interferes with paper conveyance, and setting the absolute value of the transfer bias voltage to 0 or a smaller value can lead to toner adherence to the transfer device, causing staining issues.

Innovation Solution

The image forming apparatus controls the transfer bias voltage to be applied in a direction opposite to that during image formation, using a reverse bias voltage to prevent toner adherence to the transfer device, thereby maintaining efficient paper conveyance and preventing staining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the absolute value of the transfer bias voltage is set to 0 or a smaller value during decoloring processing, then paper conveyance is improved, but toner adheres to the transfer device causing staining

Engineering Contradiction:

Improvepaper conveyanceVSAvoidtoner staining

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent applies a transfer bias voltage with opposite polarity during decoloring processing compared to normal image formation. Instead of using a positive transfer bias voltage that would attract and adhere toner to the transfer device, the system uses a negative transfer bias voltage that repels toner particles, preventing them from adhering to the transfer device while still enabling paper conveyance through the decoloring section.

Inventive Principle:

Principle #13The other way round (Inversion)

2Speed

If the transfer bias voltage is reduced to enable paper conveyance with high chargeability, then paper passing is improved, but toner is adhered to the transfer device

Engineering Contradiction:

Improvepaper passing speedVSAvoidtransfer device cleanliness

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent inverts the polarity of the transfer bias voltage during decoloring operations. This inversion creates an electric field that repels toner particles from the transfer device surface, preventing toner adhesion and staining while maintaining sufficient paper conveyance capability through the decoloring section.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of operation

If the absolute value of transfer bias voltage is set low during decoloring, then paper conveyance through high chargeability paper is improved, but toner adheres to transfer device

Engineering Contradiction:

Improvepaper conveyanceVSAvoidtoner adhesion

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent employs a transfer bias voltage with reversed polarity during decoloring processing. This opposite polarity voltage creates an electric field that actively repels toner particles, preventing them from adhering to the transfer device while still allowing the paper to be conveyed through the decoloring section effectively.

Inventive Principle:

Principle #13The other way round (Inversion)

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 prevents toner adherence to the transfer device, ensuring clean operation and maintaining the integrity of the image forming process during decoloring, allowing for the reuse of paper with decolorable toner.

Implementation Method 1

the transfer bias voltage control section forms, in a case where the decoloring section decolors the medium, an electric field in a direction opposite to that of an electric field formed at the time of an image formation

Methodology Applied

Scientific EffectElectric field: Electric Field

Implementation Method 2

The decoloring section decolors the decolorable toner on the medium

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS9188911B1Image forming apparatus and image forming method

Publication Date: 2015.11.17 KK TOSHIBA

AI summary

In accordance with an embodiment, an image forming apparatus comprises an image forming section, a transfer section, a bias voltage control section, a decoloring section and a control section. The image forming section forms a toner image with decolorable toner. The transfer section transfers the toner image on a medium. The bias voltage control section controls a bias voltage to be applied to the transfer section. The decoloring section decolors the decolorable toner on the medium. The control section controls, in a case where the decoloring section decolors the medium, the bias voltage control section to form an electric field in a direction opposite to that of an electric field formed at the time of an image formation.