Developing Device Blocking Member for Exhaust Passage Clogging

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Solution Overview

Problem

The increasing rotational speed of the developing roller in image forming apparatuses leads to elevated internal pressure within the developing device housing, causing toner and developer to flow out and complicating the suppression of this pressure increase due to air introduction, which can result in clogging of the exhaust passage.

Innovation Solution

Incorporation of a blocking member that intersects the tangent connecting the exhaust passage inlet to the opposite side of the supply member, preventing developer entry into the exhaust passage and maintaining air separation from the developer, thus preventing clogging and controlling internal pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the rotational speed of the developing roller is increased to improve productivity, then the output of the image forming apparatus is improved, but the internal pressure in the device housing increases causing developer to flow out and potentially clog the exhaust passage

Engineering Contradiction:

Improveoutput of image forming apparatusVSAvoidexhaust passage functionality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A blocking member is introduced as an intermediary element between the supply member and the exhaust passage inlet. This blocking member selectively prevents developer particles from entering the exhaust passage while allowing air to pass through freely, thus resolving the contradiction by protecting the exhaust passage from clogging without affecting the pressure equalization function

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The blocking member is positioned specifically at the inlet of the exhaust passage, creating a localized protection zone. This local intervention prevents developer contamination at the critical entry point while maintaining the overall airflow dynamics and pressure balance in the device housing

Inventive Principle:

Principle #3Local quality

2Productivity

If the rotational speed of the developing roller is increased to improve productivity, then the output of the image forming apparatus is improved, but air is introduced into the device housing causing internal pressure increase and developer leakage

Engineering Contradiction:

Improveoutput of image forming apparatusVSAvoidinternal pressure increase and developer leakage

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The blocking member serves as a mediator that allows the harmful air inflow to continue (maintaining pressure balance) while preventing the harmful developer leakage. It selectively filters the mixture of air and developer particles, permitting air passage while blocking developer particles from escaping into the exhaust passage

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system is segmented into distinct functional zones: the supply member region, the blocking member filtration zone, and the exhaust passage region. This segmentation allows independent optimization of each zone, enabling high-speed rotation while maintaining pressure control and preventing leakage through the strategically positioned blocking member

Inventive Principle:

Principle #1Segmentation

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 configuration effectively suppresses the increase in internal pressure within the developing device housing, preventing developer entry into the exhaust passage and maintaining its functionality even at higher rotational speeds, as demonstrated by reduced pressure levels during experiments.

Implementation Method 1

The developer holding member includes a magnetic field generating device therein and holds the developer

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

The supply member is rotated so as to lift the developer from below on a developer lifting side in a rotational direction thereof toward the developer holding member to supply the developer

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS9804531B2Developing device including exhaust passage and blocking member and image forming apparatus

Publication Date: 2017.10.31 FUJIFILM BUSINESS INNOVATION CORP

AI summary

A developing device includes a device housing, a developer holding member, and a supply member. The device housing contains developer. The developer holding member includes a magnetic field generating device and holds the developer. The supply member is rotated so as to lift the developer from below on a developer lifting side in a rotational direction thereof toward the developer holding member. The developing device has an exhaust passage that is provided along an outer circumference of the developer holding member and that allows air in the apparatus body to be exhausted therethrough. An opposite portion is defined on an opposite side to the developer lifting side in the rotational direction of the supply member. The developing device also includes a blocking member that intersects a tangent connecting the opposite portion to the inlet so as to block entrance of the developer into the exhaust passage.