Conductive Brush Segmentation for Paper Dust Collection
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Solution Overview
Problem
Conventional electrophotographic image forming apparatuses using conductive brushes for toner charging face issues with paper dust accumulation, which degrades the charging performance and leads to cleaning failures, especially when a large number of prints are made.
Innovation Solution
Incorporating a paper dust collection brush positioned upstream of the conductive brush to prevent paper dust from accumulating on the conductive brush, ensuring effective toner charging and extended cleaning performance by maintaining the conductive brush's charging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive brush is used to charge residual toner on the intermediate transfer belt, then the cleaning performance is improved, but paper dust accumulates in the brush causing charging failure
Solution Approach 1:
The invention divides the single brush unit into two separate functional units: a first brush (conductive brush) dedicated to charging residual toner and a second brush (paper dust collection brush) dedicated to collecting paper dust. This segmentation prevents paper dust from accumulating in the conductive brush, maintaining its charging performance while separately handling paper dust removal.
Solution Approach 2:
The second brush acts as an intermediary component that collects paper dust before it can accumulate in the first brush. By positioning the second brush upstream of the first brush in the intermediate transfer belt's movement direction, it serves as a protective barrier that removes harmful paper dust particles, allowing the first brush to focus on its primary charging function without degradation.
2Productivity
If the intermediate transfer belt continuously moves to transport toner images, then productivity is improved, but paper dust is transported to the charging portion and accumulates
Solution Approach 1:
The second brush is positioned upstream of the first brush in the movement direction of the intermediate transfer belt, performing preliminary collection of paper dust before the dust reaches the charging portion. This preliminary action prevents paper dust from accumulating in the first brush, ensuring continuous efficient operation during high-speed printing.
3Power
If the conductive brush contacts the intermediate transfer belt to charge toner, then charging efficiency is improved, but paper dust is caught and accumulated in the brush
Solution Approach 1:
The invention segments the brush system into two distinct contact zones: the first brush contact portion for toner charging and the second brush contact portion for paper dust collection. This segmentation allows the first brush to maintain high charging efficiency by preventing paper dust from being entrapped in its bristles, while the second brush separately handles paper dust removal.
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 paper dust collection brush effectively prevents paper dust accumulation, maintaining the conductive brush's charging performance for a longer period, thereby preventing cleaning failures and ensuring consistent image quality even with high print volumes.
Implementation Method 1
residual toner on the intermediate transfer belt is charged to the polarity opposite to the normal charging polarity of toner by a charging unit, moved to a photosensitive member, and collected
Implementation Method 2
a small amount of paper dust, transferred from paper as a recording material at the secondary transfer portion, on the intermediate transfer belt
Data Source
AI summary
An image forming apparatus charges toner on a transfer belt by using a first brush and collects the toner, in which a second brush is provided on the upstream side of the first brush, and the amount of inroad of the second brush into the transfer belt is larger than the amount of inroad of the first brush into the transfer belt.