Transfer Voltage Control for Image Forming Apparatus

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Solution Overview

Problem

Electrophotographic image forming apparatuses face challenges in maintaining print quality due to varying resistance values of transfer members and paper sheets, particularly with special papers, leading to inconsistent current flow and requiring manual adjustment of transfer voltage settings.

Innovation Solution

An image forming apparatus with a sensing unit to measure current flow and a control device that adjusts transfer voltage to maintain a set current range, allowing for efficient control of toner image transfer onto paper sheets, reducing the need for frequent test printing and improving print quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the transfer voltage is manually adjusted to maintain print quality on special paper, then the print quality can be improved, but the operation complexity and time required for test printing increase

Engineering Contradiction:

Improveprint qualityVSAvoidoperation complexity

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The system automatically measures the resistance value of the transfer member and calculates the optimal transfer voltage without requiring manual intervention. The control unit performs self-adjustment based on measured parameters, eliminating the need for operators to manually set transfer voltage or conduct repeated test printing.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system incorporates a sensing unit that continuously measures the resistance value of the transfer member and provides feedback to the control unit. This feedback loop enables automatic adjustment of transfer voltage based on real-time measurements, ensuring consistent print quality without manual intervention.

Inventive Principle:

Principle #23Feedback

2Reliability

If the transfer voltage is increased to improve current flow on high resistance paper, then the current flow improves, but the transfer voltage setting becomes less effective when resistance values vary significantly

Engineering Contradiction:

Improvecurrent flow consistencyVSAvoidtransfer voltage effectiveness

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system dynamically changes the transfer voltage parameter based on the measured resistance value of the transfer member. Instead of using a fixed transfer voltage, the control unit calculates and applies an optimized voltage value that adapts to the specific resistance characteristics of the transfer member and paper combination, ensuring effective current flow across varying conditions.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If a wide allowable range of transfer voltage change is set to accommodate varying resistance values, then the system can handle different paper types, but the print quality control precision decreases

Engineering Contradiction:

Improvepaper type compatibilityVSAvoidprint quality control precision

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system transitions from a static transfer voltage setting to a dynamic adjustment mechanism. The control unit continuously measures the resistance value and automatically adjusts the transfer voltage in real-time, enabling the system to adapt to different paper types and resistance values while maintaining precise print quality control through active feedback.

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

This solution enables precise control of current flow during toner image transfer, enhancing print quality on paper sheets with varying resistance values, reducing the workload associated with achieving desired print quality by allowing users to set current ranges rather than transfer voltage.

Implementation Method 1

A voltage of the opposite polarity of that of the toner image (this voltage will be hereinafter also referred to as 'transfer voltage') is applied to the transfer member. With this transfer voltage, the toner image is attracted to the transfer member from the image carrier, and is then transferred onto the paper sheet

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatics

Implementation Method 2

a sensing unit configured to sense a magnitude of the current flowing in the transfer target member passing through the contact portion between the image carrier and the transfer member

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS9841707B2Image forming apparatus, control method, and control program in which a magnitude of a current to flow in a paper sheet at the time of toner image transfer can be set

Publication Date: 2017.12.12 KONICA MINOLTA INC

AI summary

An image forming apparatus includes: an image carrier configured to carry a toner image; a transfer member configured to transfer the toner image onto a transfer target member by applying a transfer voltage of the opposite polarity of the polarity of the toner image to the transfer target member, the transfer member being in contact with the image carrier; an accepting unit configured to accept a setting for changing a preset current range to a new current range, the preset current range being defined by one of a lower limit of a current flowing in the transfer target member and an upper limit of the current; a sensing unit configured to sense a magnitude of the current flowing in the transfer target member; and a control device configured to control the transfer voltage so that the magnitude of the sensed current falls within the new current range.