Developing Apparatus Screw Abrasion Reduction

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Solution Overview

Problem

Existing developing apparatuses using a two-component developer face issues with excessive discharge of developer due to air currents and increased abrasion of conveyance screws, which limits the apparatus' operating life.

Innovation Solution

The developing apparatus incorporates a developer container with a first and second chamber, a first and second conveyance screw, a discharge path with a discharge port, and a magnet, along with a third blade member and a protruding portion on the rotation shaft to manage developer flow and reduce abrasion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If a magnet is arranged downstream of the discharge port to form an agent accumulation area, then excessive discharge of developer is reduced, but the force required for discharging developer increases and abrasion of the conveyance screw increases

Engineering Contradiction:

Improveexcessive discharge of developerVSAvoidabrasion of conveyance screw

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The discharge port is positioned upstream of the magnet's agent accumulation area, allowing developer to be discharged before encountering the magnetic field. This preliminary discharge action prevents developer from being held by the magnet, thereby reducing the force required and minimizing abrasion of the conveyance screw while still utilizing the magnet to control excessive discharge.

Inventive Principle:

Principle #10Preliminary action

2Loss of substance

If the discharge port is covered with an agent accumulation area formed by a magnetic field, then excessive discharge of developer is reduced, but the operating life of the developing apparatus is limited due to increased abrasion

Engineering Contradiction:

Improveexcessive discharge of developerVSAvoidoperating life of developing apparatus

Core Design Contradiction:

Loss of substanceVSDuration of action of stationary object

Solution Approach 1:

By positioning the discharge port upstream of the magnet, the developer is discharged before reaching the agent accumulation area. This preliminary discharge prevents the conveyance screw from having to push developer against the magnetic field, significantly reducing abrasion and extending the operating life of the developing apparatus.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If a magnet is used to attract developer and form an agent accumulation area, then developer discharge control is improved, but the conveyance screw must slide against developer with limited flowability, increasing abrasion

Engineering Contradiction:

Improvedeveloper discharge controlVSAvoidconveyance screw durability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The discharge port is arranged upstream of the magnet so that developer discharge occurs before the developer enters the agent accumulation area. This preliminary discharge action maintains developer flowability during conveyance, allowing the conveyance screw to operate smoothly without sliding against magnetically-bound developer, thereby preserving screw durability.

Inventive Principle:

Principle #10Preliminary 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 configuration effectively reduces excessive developer discharge and minimizes conveyance screw abrasion, enhancing the apparatus' operating life and reliability.

Implementation Method 1

a magnet arranged downstream of an upstream end of the discharge port in the first direction

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

the magnet is arranged downstream of an upstream end of the discharge port in the first direction

Methodology Applied

Scientific EffectMagnetism: Magnetism

Implementation Method 3

a first conveyance screw arranged in the first chamber, the first conveyance screw including a rotation shaft, a first blade member helically formed on an outer circumference surface of the rotation shaft

Methodology Applied

Scientific EffectScrew mechanism: Screw

Data Source

PatentUS20250110424A1Developing apparatus

Publication Date: 2025.04.03 CANON KK

AI summary

A developing apparatus includes a first conveyance screw including a first blade member and a second blade member, a discharge path, and a magnet, wherein the first conveyance screw further includes a third blade member arranged in the discharge path, arranged downstream of the second blade member in a first direction, and configured to convey the developer in the first direction, wherein a discharge port is arranged downstream of an upstream end of the third blade member in the first direction, wherein the magnet is arranged downstream of an upstream end of the discharge port in the first direction, and wherein a protruding portion protruding in a radial direction of a rotation shaft is provided on the rotation shaft in an area located downstream of the third blade member and upstream of the magnet in the first direction, the area overlapping the upstream end of the discharge port.