Image Forming Apparatus Non-Image Additive Supply

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Solution Overview

Problem

Image forming apparatuses face challenges in effectively removing discharge products during non-image formation, leading to potential image defects due to the adhesion of NOx or SOx on the photoconductor, which can cause scratches and improper transfer when external additives and carriers are pressed between the photoconductor and transfer rollers.

Innovation Solution

The apparatus increases the potential difference between the charging and developing voltages to supply a larger number of external additives, which strongly adhere to and remove discharge products, and separates the photoconductor and transfer rollers to prevent carrier-induced defects, using zinc stearate as external additives and separating the photoconductor and first transfer roller to prevent carrier pressing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external additives and carriers are supplied to the photoconductor during non-image formation, then discharge products can be removed, but scratches and improper transfer occur when carriers are pressed between the photoconductor and transfer rollers

Engineering Contradiction:

Improvedischarge product removal effectivenessVSAvoidscratches and improper transfer

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The process is segmented into two distinct phases: (1) During non-image formation, external additives are supplied to remove discharge products while carriers are prevented from reaching the photoconductor; (2) During image formation, the normal developing process occurs without external additives. This temporal segmentation allows discharge product removal without carrier-induced damage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The harmful carriers are extracted or removed from the developing unit during non-image formation, leaving only the beneficial external additives to act on the photoconductor surface. This selective removal prevents carrier pressing between the photoconductor and transfer rollers while maintaining discharge product removal capability.

Inventive Principle:

Principle #2Taking out (Extraction)

2Stability of the object's composition

If the photoconductor and transfer rollers remain in contact during non-image formation, then transfer alignment is maintained, but carriers pressed between them cause image defects

Engineering Contradiction:

Improvetransfer alignment stabilityVSAvoidimage quality

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The system dynamically adjusts the state of the photoconductor-transfer roller interface based on operational mode. During non-image formation, the system creates conditions where carriers are prevented from entering the contact zone, effectively making the interface dynamically protective. During image formation, normal contact and carrier flow are restored.

Inventive Principle:

Principle #15Dynamics

3Reliability

If external additives are supplied during image formation, then more discharge products are removed, but image defects such as white patches and dents occur

Engineering Contradiction:

Improvedischarge product removalVSAvoidimage quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

External additives are supplied periodically or intermittently during non-image formation periods, rather than continuously during image formation. This periodic supply pattern allows discharge product removal to occur during idle periods while preventing additive-related image defects during active image formation periods.

Inventive Principle:

Principle #19Periodic 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 effectively removes discharge products, reducing image defects such as white patches and dents, and prevents scratches by increasing the supply of external additives and separating the photoconductor and transfer rollers, resulting in improved image quality under high temperature and humidity conditions.

Implementation Method 1

a charging unit that includes a rotatable charging member that charges the image carrier

Methodology Applied

Scientific EffectElectrostatic charging: Electrostatics

Implementation Method 2

the external additive is supplied to the image carrier that rotates... external additives, which strongly adhere to and remove discharge products

Methodology Applied

Scientific EffectElectrostatic adhesion: Electrostatics

Data Source

PatentUS10175603B2Image forming apparatus without color points appeared in an image

Publication Date: 2019.01.08 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An image forming apparatus includes a rotatable image carrier that carries an image; a charging unit that includes a rotatable charging member that charges the image carrier; a developing unit that supplies developer to the image carrier that is charged, the developer containing at least toner and a carrier, an external additive being added to the toner; a transfer unit that includes a transfer member that transfers the image formed on the image carrier to a transfer material; and a cleaning unit that cleans a surface of the image carrier. In the image forming apparatus, during image non-formation, the external additive is supplied to the image carrier that rotates, and the image carrier and at least the transfer member are separated from each other.