Conveyance Belt Electrostatic Adhesion Duplex Printing

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Solution Overview

Problem

Conventional image forming apparatuses face issues with stable reverse conveyance of recording media due to decay in electrostatic adhesion force, leading to improper adherence and separation of the recording medium from the conveyance belt during duplex printing.

Innovation Solution

An improved image forming apparatus design includes a recording head, a conveyance belt looped around rollers for electrostatic adherence, a reverse passage for turning and re-routing the recording medium, and a charger positioned between the bypass passage and the conveyance belt to maintain electrostatic charge, ensuring stable reverse conveyance by guiding the recording medium back onto the belt.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the recording medium is conveyed on the conveyance belt using electrostatic force, then the recording medium can be held and conveyed stably, but the electrostatic adhesion force decays during separation and return, causing improper adherence

Engineering Contradiction:

Improvestable conveyanceVSAvoidelectrostatic adhesion force

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The charger is positioned to charge the conveyance belt in advance before the recording medium needs to be conveyed. By pre-charging the belt surface where the medium will be placed, the system ensures that sufficient electrostatic adhesion force is available when needed, preventing improper adherence during separation and return cycles

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The charger acts as an intermediary device that restores and maintains the electrostatic charge on the conveyance belt. This mediator component compensates for charge decay that occurs during separation and return operations, ensuring continuous reliable adhesion without requiring mechanical modifications to the belt or medium

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the recording medium is turned around by the reversing unit and sent back to the conveyance belt, then duplex printing can be achieved, but the recording medium separates from the belt due to decayed electrostatic adhesion

Engineering Contradiction:

Improveduplex printing capabilityVSAvoidadherence stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The charger is positioned to pre-charge the conveyance belt at the return point before the recording medium arrives. This preliminary charging action ensures that when the medium is turned around and sent back, the belt already has sufficient electrostatic charge to immediately re-adhere the medium, preventing separation during the critical return phase of duplex printing

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The charger serves as a mediator that bridges the gap between the reversing unit and the conveyance belt. By restoring electrostatic charge at the strategic location between these components, the charger enables reliable re-adherence after the medium is turned around, making duplex printing operations stable and reliable

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the charger is disposed inside the bypass passage to charge the conveyance belt, then electrostatic adhesion can be maintained, but the structure becomes more complex

Engineering Contradiction:

Improveelectrostatic adhesion maintenanceVSAvoidcharger positioning structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of placing the charger inside the bypass passage, the invention uses the outer surface of the conveyance belt as a copy or alternative charging surface. The charger is positioned to charge this outer surface, which then transfers the electrostatic charge to the recording medium through the belt, achieving the same adhesion maintenance function with simpler external positioning

Inventive Principle:

Principle #26Copying

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 solution ensures reliable adherence and stable reverse conveyance of the recording medium, maintaining electrostatic adhesion force and preventing separation, thereby enhancing the performance of duplex printing operations.

Implementation Method 1

a conveyance belt looped around at least two rollers to adhere a recording medium thereto by electrostatic force and convey the recording medium

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Implementation Method 2

a charger positioned between the bypass passage and the conveyance belt to maintain electrostatic charge

Methodology Applied

Scientific EffectElectrostatic charge: Electrostatics

Data Source

PatentUS8714682B2Image forming apparatus

Publication Date: 2014.05.06 RICOH CO LTD

AI summary

An image forming apparatus includes a recording head, a conveyance belt, a reverse passage, and a charger. The belt is looped around at least two rollers to adhere a recording medium thereto by electrostatic force and convey the medium. The belt defines a normal conveyance area in which the medium is conveyed in a first direction with the medium facing the head. The reverse passage sends the medium back again to a portion of the belt upstream from the head in the first direction. The reverse passage includes an opposite conveyance area of the belt in which the medium is conveyed in a second direction and a bypass passage to guide the medium separated from the opposite conveyance area toward the normal conveyance area. The charger is disposed between the bypass passage and an outer surface of the belt to charge the outer surface of the belt.