Transfer Device Shield Member for Toner Scattering Control

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Solution Overview

Problem

In color image forming apparatuses, the repulsive force used to facilitate toner transfer onto a recording medium also causes toner from test images to scatter, contaminating optical detectors and other components, leading to detection failures and poor separation of the recording medium from the intermediate transfer belt.

Innovation Solution

A shield member is disposed between the test image and the transfer member to shield the test image from the electrical field generated between the image bearing member and the transfer member, preventing toner scattering and allowing for accurate detection of test image density without the need for complex control systems or additional structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a repulsive force is applied to facilitate toner transfer onto the recording medium, then transfer efficiency is improved, but toner from test images scatters and contaminates optical detectors and other components

Engineering Contradiction:

Improvetransfer efficiencyVSAvoidtoner scattering contamination

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

A shield member is introduced as an intermediary element positioned between the test image area and the transfer member. This shield blocks the repulsive force generated during toner transfer from acting on test image toner, preventing scattering and contamination while allowing the transfer process to continue normally in the image forming area.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The transfer device is segmented into distinct functional zones: a test image forming area, an image forming area, and a transfer area. The shield member is positioned to isolate the test image area from the transfer forces acting on the recording medium, allowing different regions to operate independently without interfering with each other.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If test images are formed on the intermediate transfer belt for toner density adjustment, then toner density control is improved, but the scattered toner contaminates the optical detector causing detection failure

Engineering Contradiction:

Improvetoner density controlVSAvoidoptical detector detection accuracy

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The shield member serves as a protective intermediary that isolates the optical detector from scattered toner particles generated during test image formation. This allows the optical detector to accurately measure test image density while the shield prevents contaminating particles from reaching the detector surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If a shield member is introduced to prevent toner scattering, then contamination is reduced, but device complexity increases

Engineering Contradiction:

Improvecontamination preventionVSAvoiddevice configuration complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The shield member is designed as a thin, flexible component that can be easily integrated into the existing transfer device structure. This thin-film approach provides effective contamination protection while minimizing the added complexity and space requirements compared to more substantial shielding structures.

Inventive Principle:

Principle #30Flexible shells and thin films

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

The shield member effectively prevents toner scattering, ensuring accurate detection of test image density and maintaining the cleanliness of components, while simplifying the device configuration and reducing the risk of contamination.

Implementation Method 1

shield the test image from an electrical field generated between the image bearing member and the transfer member

Methodology Applied

Scientific EffectElectrical field: Electric Field

Implementation Method 2

transfer the toner image from the image bearing member onto the recording medium in the transfer nip

Methodology Applied

Scientific EffectElectrostatic transfer: Electrostatics

Implementation Method 3

an electrostatic force from the back tension roller acts on the toner, thereby repelling the toner and hence facilitating transfer of the toner from the intermediate transfer belt to the recording medium

Methodology Applied

Scientific EffectElectrostatic repulsion: Ion Repulsion/Attraction

Data Source

PatentUS8750734B2Transfer device and image forming apparatus including same

Publication Date: 2014.06.10 RICOH CO LTD

AI summary

A transfer device includes an image bearing member, a transfer member, a test image detector, and a shield member. The image bearing member bears a toner image on a surface thereof within an image forming area. The transfer member disposed opposite the image bearing member forms a transfer nip between the transfer member and the image bearing member through which the recording medium is conveyed and transfers the toner image from the image bearing member onto the recording medium in the transfer nip. The test image detector disposed downstream from the transfer nip in the direction of conveyance of the recording medium detects a density of a test image for adjustment of toner density formed outside the image forming area. The shield member disposed between the test image and the transfer member shields the test image from an electrical field generated between the image bearing member and the transfer member.