Developing Roller Speed Control for Toner Leakage Prevention

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Solution Overview

Problem

Toner leakage occurs around the developing roller in image-forming apparatuses due to toner accumulation, which forms lumps and creates gaps between the thickness regulating blade and the developing roller, leading to toner leakage.

Innovation Solution

The image-forming apparatus includes a controller that manages the developing roller's speed and position, initiating a normal-speed rotation process followed by a halting process, then a low-speed rotation process, and finally a cleaning process to prevent toner lump formation and leakage. The controller causes the developing roller to stop rotating, then restart at a lower speed while maintaining contact, allowing the toner lump to break and pass through the thickness regulating blade, and subsequently moves the toner to the belt for collection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the developing roller rotates at high speed continuously, then productivity is improved, but toner accumulates to form lumps causing toner leakage

Engineering Contradiction:

Improveimage formation speedVSAvoidtoner leakage prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The developing roller alternates between high-speed rotation during image formation and low-speed rotation during toner removal cycles. This periodic action allows the system to maintain high productivity during normal operation while periodically eliminating toner accumulation that would otherwise cause leakage and reliability issues.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

Before toner accumulation causes leakage problems, the system performs preliminary low-speed rotation to remove accumulated toner. This preventive maintenance approach ensures that toner is removed before it forms hard lumps that would create gaps and cause leakage, maintaining system reliability.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the developing roller stops rotating, then toner accumulation is prevented, but productivity decreases

Engineering Contradiction:

Improvetoner distribution uniformityVSAvoidimage formation efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Instead of continuous stopping, the system uses periodic low-speed rotation intervals between high-speed image formation cycles. This maintains toner distribution uniformity through occasional gentle mixing while minimizing productivity loss by keeping the roller mostly in motion at high speed during actual image formation.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system changes the rotation speed parameter from high speed during image formation to low speed during toner removal, rather than completely stopping. This parameter adjustment maintains sufficient motion to prevent toner hardening while reducing energy consumption and allowing longer operational cycles at high productivity.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If a thickness regulating blade is used to control toner thickness, then manufacturing precision is improved, but toner accumulates between the blade and roller causing leakage

Engineering Contradiction:

Improvetoner thickness controlVSAvoidtoner leakage

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The system periodically reverses or slows the developing roller rotation during low-speed intervals, creating relative motion between the thickness regulating blade and roller surface. This periodic action prevents toner from hardening in the gap between the blade and roller, eliminating the source of leakage while maintaining precise thickness control during high-speed image formation.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the rotation speed of the developing roller based on operational phase: high speed for image formation with precise thickness control, and low or reverse speed for toner removal. This dynamic operation prevents static toner accumulation between the blade and roller that would cause leakage.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10311345B2Image-forming apparatus configured to control rotation of developing roller to prevent toner leakage

Publication Date: 2019.06.04 BROTHER KOGYO KK

AI summary

An image-forming apparatus includes a photosensitive drum, a developing roller, a collecting roller, a belt, a cleaner, and a controller. In response to receiving a signal, the controller performs a process staring with a first process and ending with a second process. The controller rotates the developing roller at a contact position at a first speed in the first process. The controller causes the collecting roller to move residual toner to the belt to allow the cleaner to clean the belt while the developing roller is separated from the photosensitive drum in the second process. The process further includes: (a) causing the developing roller to halt rotating while maintaining the developing roller at the contact position; and (b) causing the developing roller halted in the (a) causing to start rotating at a second speed lower than the first speed while maintaining the developing roller at the contact position.