Brush Roller Belt Cleaning with Opposing Electric Fields
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Solution Overview
Problem
Existing image forming apparatuses face inefficiencies in toner recovery from endless belts, such as the intermediate transfer belt and secondary transfer belt, due to toner being charged with a polarity reverse to the toner charge polarity, leading to incomplete cleaning and increased toner return to the belt.
Innovation Solution
The apparatus employs a configuration with a first and second brush roller and corresponding power supplies generating electric fields in opposite directions, optimizing contact areas and lengths to enhance toner collection efficiency, specifically by ensuring LB1>LR1 and LN1<LN2, which reduces charge injection and discharging, allowing for effective collection of toner with varying polarities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single brush roller is used to clean the endless belt, then the device complexity is low, but the toner recovery efficiency is insufficient due to toner charge polarity reversal
Solution Approach 1:
The cleaning unit is divided into multiple brush rollers (first brush roller and second brush roller) positioned at different locations along the endless belt. Each brush roller is equipped with independently controllable voltage application, allowing separate optimization for different toner charge polarities. This segmentation enables targeted cleaning of toner with reverse polarity without requiring complete system redesign.
Solution Approach 2:
Different voltage polarities are applied at different locations along the endless belt. The first brush roller applies voltage of one polarity to collect toner of that polarity, while the second brush roller applies voltage of opposite polarity to collect toner with reverse polarity. This local differentiation of cleaning parameters optimizes toner recovery efficiency for mixed polarity toner deposits without uniformly increasing system complexity.
2Productivity
If voltage is increased to improve toner collection, then toner recovery efficiency improves, but charge injection and discharging increase causing toner return to the belt
Solution Approach 1:
The voltage application is made dynamic and location-dependent rather than static and uniform. By applying different voltage polarities at different locations along the endless belt, the system adapts to the varying charge states of toner particles at different positions. This dynamic approach allows effective toner collection while minimizing excessive voltage application that would cause charge injection and discharging.
Solution Approach 2:
Multiple brush rollers serve as intermediaries between the power supply and the endless belt, each mediating the voltage application to specific regions. This intermediary structure allows gradual and controlled voltage application, preventing sudden high-voltage spikes that would cause discharge and toner return to the belt.
3Productivity
If the contact area between brush roller and belt is increased, then toner collection efficiency improves, but the risk of charge polarity reversal increases
Solution Approach 1:
The contact area is segmented into multiple zones, each with independently controlled voltage polarity. This allows the total contact area to be increased for better toner collection while maintaining stable charge polarity in each segment through localized voltage control, preventing overall charge polarity reversal.
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 significantly improves toner cleaning performance by reducing toner return to the belt and preventing charge polarity reversal, ensuring high cleaning efficiency even when increasing the voltage applied to the upstream brush roller.
Implementation Method 1
a first power supply generating an electric field in a first direction between the first brush roller and the first roller
Implementation Method 2
a second power supply generating an electric field in a second direction which is a direction opposite to the first direction between the second brush roller and the second roller
Data Source
AI summary
Relationships of LB1>LR1 and LN1<LN2 are satisfied, where LB1 is a length of a first contact area in which a first brush roller and an endless belt come into contact with each other. LR1 is a length of a second contact area in which the first roller and the endless belt come into contact with each other.LN1 is a length of an area in which the first contact area and the second contact area overlap with each other. A third contact area is an area in which the second brush roller and the endless belt come into contact with each other. A fourth contact area is an area in which the second roller and the endless belt come into contact with each other. LN2 is a length of an area in which the third contact area and the fourth contact area overlap with each other.