Developer Discharge Duct Airflow Layout to Prevent Toner Buildup

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Solution Overview

Problem

The increasing speed of electrophotographic image forming apparatuses leads to an increased amount of collected developer, which can cause blockage in the flow passage for collecting the developer, necessitating a solution to suppress developer deposition.

Innovation Solution

A developing device with a developer discharging duct featuring suction ports, a discharge port, and a side intake port, along with a partition wall to manage airflow and reduce developer deposition, including a configuration that directs air flow to minimize blockages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the image forming apparatus increases operating speed, then productivity is improved, but the amount of collected developer increases causing flow passage blockage

Engineering Contradiction:
Improveoperating speedVSAvoidflow passage blockage probability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent extracts the harmful effect of developer deposition from the flow passage by introducing a separate air intake port that draws air through the flow passage. This air flow continuously removes deposited developer particles, preventing blockage while allowing the system to operate at high speeds with increased developer collection volumes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies pneumatic principles by using air flow generated through the side intake port to transport and remove developer particles from the flow passage. The air current creates a cleaning effect that prevents accumulation and blockage, enabling reliable operation at high productivity levels.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If air flow is increased to discharge deposited developer, then flow passage blockage is reduced, but developer may be dispersed to other areas

Engineering Contradiction:
Improveflow passage blockage preventionVSAvoiddeveloper dispersion
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by positioning the side intake port at a specific location where air flow can effectively remove developer from the flow passage without creating excessive turbulence. The air intake is localized to the flow passage area, providing targeted cleaning while containing the air flow within the duct structure to prevent developer dispersion to other areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses air as an intermediary medium to remove developer from the flow passage. The air flow acts as a carrier that transports deposited developer particles to the discharge port in a controlled manner, preventing direct contact between developer particles and surrounding areas while maintaining effective blockage prevention.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration effectively suppresses developer deposition and reduces the likelihood of blockages, thereby minimizing the chances of stopping the image forming apparatus.

Implementation Method 1

a developer discharging duct through which the developer is sucked from an image holding body side

Methodology Applied
Scientific EffectSuction: Suction

Implementation Method 2

a side intake port for sucking air is formed in one duct side wall of the two duct side walls

Methodology Applied
Scientific EffectAir flow: Convection

Implementation Method 3

a transport direction of a collected developer transport passage through which the developer remaining without being developed to the image holding body is collected from the development roll and is sent along the intersection direction

Methodology Applied
Scientific EffectAir flow transport: Advection

Data Source

PatentEP4697101A1Developing device
Publication Date: 2026.02.18 FUJIFILM BUSINESS INNOVATION CORP
  • EP4697101A1 patent drawingFigure 1
  • EP4697101A1 patent drawingFigure 2~3
  • EP4697101A1 patent drawingFigure 4

AI summary

A developing device includes a development roll that rotates while holding a developer, an image holding body that is disposed to face the development roll and that rotates, and a developer discharging duct through which the developer is sucked from an image holding body side and the developer is discharged to another place, in which the developer discharging duct includes a duct front wall that is disposed on the image holding body side and that has suction ports for sucking the developer, which are formed in end portions of the duct front wall on both sides in an intersection direction intersecting a rotation movement direction of the development roll, a duct rear wall that is positioned on a side opposite to the image holding body with respect to the duct front wall, and two duct side walls that are positioned at the end portions on both sides in the intersection direction, a discharge port for discharging the developer is formed in one duct side wall of the two duct side walls, at a position adjacent to the duct rear wall, and a side intake port for sucking air is formed in one duct side wall of the two duct side walls.