Continuous-Media Image Transfer With Pre-Transfer Bias Timing

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Solution Overview

Problem

Conventional image forming apparatuses face issues with color misregistration, image defects, and paper wrinkling during the transfer process on continuous recording media due to unstable sheet conveyance and changing attraction forces between the sheet and intermediate transfer belt.

Innovation Solution

An image forming apparatus with a hardware processor controlling the speed of the intermediate transferer and conveyor to stabilize the conveyance of continuous recording media, applying a transfer bias to the secondary transferer after pressing against the intermediate transferer and before primary transfer, ensuring the conveyor speed exceeds the intermediate transferer speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the fixing speed is made higher than the transfer speed to suppress sheet meandering, then sheet conveyance stability is improved, but the load on the intermediate transfer belt changes causing speed variations and color misregistration

Engineering Contradiction:

Improvesheet conveyance stabilityVSAvoidcolor registration accuracy

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The transfer bias is applied to the secondary transferer before the primary transfer starts, which stabilizes the attraction force between the sheet and intermediate transfer belt in advance. This preliminary action prevents load changes during transfer that would cause speed variations and color misregistration, while allowing the fixing speed to remain higher than transfer speed for stable sheet conveyance.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If the attraction force between sheet and intermediate transfer belt changes during transfer, then the load on intermediate transfer belt changes, but this causes speed variations and color misregistration

Engineering Contradiction:

Improvetransfer process flexibilityVSAvoidcolor registration accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The transfer bias is applied in advance before primary transfer begins, stabilizing the attraction force between sheet and intermediate transfer belt beforehand. This prevents load changes during the transfer process that would cause intermediate transfer belt speed variations and subsequent color misregistration.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the speed of intermediate transfer belt changes, then tension on sheet becomes unstable, but this results in unstable sheet conveyance and paper wrinkles

Engineering Contradiction:

Improvetransfer speedVSAvoidsheet conveyance stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The transfer bias is applied before primary transfer starts, which stabilizes the attraction force and prevents intermediate transfer belt speed changes. This maintains stable tension on the sheet throughout the transfer process, preventing unstable conveyance and paper wrinkles.

Inventive Principle:

Principle #10Preliminary action

4Ease of operation

If sheet conveyance becomes unstable, then sheet undulates and contacts fixing belt before toner image fixing, but this causes image defects

Engineering Contradiction:

Improveconveyance controlVSAvoidimage quality

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The transfer bias is applied in advance before primary transfer, stabilizing the attraction force between sheet and intermediate transfer belt. This ensures stable sheet conveyance through the transfer and fixing sections, preventing sheet undulation and contact with the fixing belt that would cause image defects.

Inventive Principle:

Principle #10Preliminary 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 approach stabilizes the conveyance and tension of the recording medium, reducing color misregistration, image defects, and paper wrinkling, thereby minimizing waste sheets and enhancing print quality.

Implementation Method 1

a secondary transferer to which a transfer bias for secondarily transferring the toner image on the intermediate transferer to a continuous recording medium is applied

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Data Source

PatentUS12393140B2Image forming apparatus and storage medium

Publication Date: 2025.08.19 KONICA MINOLTA INC

AI summary

Disclosed is an image forming apparatus including: an image former that includes an intermediate transferer, and a secondary transferer to which a transfer bias for secondarily transferring the toner image on the intermediate transferer to a continuous recording medium is applied; a conveyor that is arranged on a downstream side of the image former and conveys the continuous recording medium; and a hardware processor that controls a speed of the intermediate transferer and a speed of the continuous recording medium conveyed by the conveyor. The hardware processor controls a timing at which the transfer bias is applied to the secondary transferer, performs control such that the speed of the continuous recording medium is higher than the speed of the intermediate transferer, and starts application of the transfer bias after the secondary transferer is pressed against the intermediate transferer and before the primary transfer is started.