Developing Device Reverse Rotation Clears Toner Clogging

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Solution Overview

Problem

Image forming apparatuses face defective discharge issues at the discharge port due to overflow and clogging of two-component developers, leading to inefficient toner distribution and image quality problems.

Innovation Solution

The apparatus employs a developing device with a transporting unit that reversely rotates at high speed to clear blockages and then forwardly rotates at high speed to maintain developer flow, ensuring proper discharge by altering rotational directions and speeds to manage developer flow and pressure effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the transporting unit rotates at normal speed in the forward direction, then the two-component developer is transported through the developing roller, but the developer overflows and clogs at the discharge port causing defective discharge

Engineering Contradiction:

Improvedischarge reliabilityVSAvoiddeveloper clogging and overflow

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The transporting unit reverses its rotation direction to discharge the two-component developer from the discharge port. By rotating in the reverse direction, the transporting unit creates negative pressure that draws the developer toward the discharge port, preventing overflow and clogging while ensuring reliable discharge of the developer from the storage chamber

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If the transporting unit rotates at high speed in reverse direction, then the developer discharge is improved, but the rotational speed exceeds normal development speed

Engineering Contradiction:

Improvedeveloper discharge efficiencyVSAvoidtransporting unit rotational speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The transporting unit alternates between forward rotation during normal development and reverse rotation during discharge operations. This periodic switching of rotation directions allows the system to maintain normal development speed during imaging while achieving high-speed reverse rotation specifically for discharge, eliminating the need to sustain high speeds continuously

Inventive Principle:

Principle #19Periodic action

3Productivity

If the transporting unit rotates forward at high speed, then developer flow is maintained, but energy consumption increases

Engineering Contradiction:

Improvedeveloper circulation efficiencyVSAvoidtransporting unit energy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The transporting unit dynamically adjusts its rotation direction based on operational requirements. During normal development, it rotates forward at standard speed to maintain developer circulation. During discharge operations, it reverses direction to efficiently clear the discharge port. This dynamic switching optimizes energy consumption by avoiding continuous high-speed operation

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 approach effectively eliminates defective discharge and maintains optimal developer flow, preventing clogging and ensuring consistent image quality by reversing and then forwarding the transporting units to manage developer distribution efficiently.

Implementation Method 1

a first operation of reversely rotating the transporting unit at a high speed so that (i) a rotational direction of the transporting unit is an opposite direction to that at a time of development and (ii) a rotational speed of the transporting unit is higher than that at the time of development

Methodology Applied

Scientific EffectReverse rotation flow generation:

Implementation Method 2

forwardly rotates at high speed to maintain developer flow, ensuring proper discharge by altering rotational directions and speeds to manage developer flow and pressure effectively

Methodology Applied

Scientific EffectForward rotation flow generation:

Data Source

PatentUS10649364B1Image forming apparatus

Publication Date: 2020.05.12 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An image forming apparatus includes a developing device. The developing device transports a two-component developer by a transporting unit so that the two-component developer passes through a developing roller. The two-component developer is stored in a storage chamber provided with a transporting path. The transporting unit rotates in the transporting path. The developing device causes a portion of the two-component developer to overflow from a discharge port provided at the transporting path, and to discharge the two-component developer. The image forming apparatus has a period in which a first operation is executed, the first operation of reversely rotating the transporting unit at a high speed so that a rotational direction of the transporting unit is an opposite direction to that at a time of development and a rotational speed of the transporting unit is higher than that at the time of development.