Development Sleeve Reverse Rotation Toner Collection

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Solution Overview

Problem

Existing image forming apparatuses face issues with toner accumulation on toner capture sheets leading to defective images due to irregular vibrations, requiring a method to collect toner efficiently during non-image forming without increasing apparatus size.

Innovation Solution

The image forming apparatus includes a development sleeve with a rotatable developer bearing member, a fixed magnet, and a regulation blade, where the toner capture sheet is positioned to be out of the developer's path during image forming but within it during reverse rotation, allowing for toner collection without the need for additional space or an electromagnet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an electromagnet is provided below the development region to collect toner during non-image forming, then toner collection effectiveness is improved, but the apparatus size increases

Engineering Contradiction:

Improvetoner collection effectivenessVSAvoidapparatus size

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent combines the toner collection function with the existing development sleeve and magnet structure. The magnet, already present for developer bearing, is utilized to attract and collect toner from the toner capture sheet during reverse rotation, eliminating the need for a separate electromagnet and reducing apparatus size while maintaining collection effectiveness

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The development sleeve is given dual functionality: it serves both as the developer bearing member during image forming and as the toner collection mechanism during non-image forming through reverse rotation. The magnet similarly serves both developer retention and toner collection purposes, reducing the need for additional components

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If the toner capture sheet is positioned to contact the development sleeve during image forming, then toner capture is improved, but defective images occur due to toner layer collapse from vibration

Engineering Contradiction:

Improvetoner capture effectivenessVSAvoidimage quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent positions the toner capture sheet to contact the development sleeve during image forming to preliminarily capture scattered toner before it can cause defects. The sheet is strategically positioned at the downstream side of the SB gap where toner tends to fall, enabling early interception of scattered toner particles

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs reverse rotation of the development sleeve during non-image forming to invert the normal operational direction. This reverse rotation brings the toner capture sheet into contact with the development sleeve to collect accumulated toner, preventing toner layer collapse and subsequent image defects while maintaining normal operation during image forming

Inventive Principle:

Principle #13The other way round (Inversion)

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 collects toner accumulating on the toner capture sheet during non-image forming, reducing defective image occurrences by 40% compared to conventional methods, without requiring additional space for an electromagnet, thus maintaining apparatus size efficiency.

Implementation Method 1

a magnet having a plurality of magnetic poles and generating a magnetic field for allowing the development sleeve to bear the developer on the surface of the development sleeve

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

if the toner electrostatically adhering to the surface of the carrier in the developer on the development sleeve is separated from the carrier by the centrifugal force

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 3

the magnetic brush of the developer formed on the development sleeve starts falling down on the downstream side of the SB gap in the rotational direction of the development sleeve

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS11662671B2Image forming apparatus having development apparatus including sheet member which is disposed below position on developer bearing member where developer bearing member is closest to image bearing member

Publication Date: 2023.05.30 CANON KK

AI summary

An image forming apparatus includes a controller, a drive unit, a developer bearing member, a regulation blade, and a sheet member. During non-image forming, the controller executes a control mode for controlling the drive unit to rotatably drive the developer bearing member in a second direction opposite to a first direction, and then rotatably drive the developer bearing member in the first direction. A portion above a horizontal line passing through a tip of the regulation blade out of the sheet member is disposed in a moving path of a developer born by the developer bearing member when the drive unit rotatably drives the developer bearing member in the second direction in the control mode, and is not disposed in the moving path of the developer born by the developer bearing member when the drive unit rotatably drives the developer bearing member in the first direction during image forming.