Charge Neutralizer and Collecting Unit for Image Quality in Cleaner-less Printers
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Solution Overview
Problem
In cleaner-less type image forming apparatuses, adhering materials like paper dust and residual toner on the photosensitive drum can lead to image defects due to reduced charge neutralization and collection performance.
Innovation Solution
The apparatus includes a charge neutralizer and a collecting unit with conductivity, positioned downstream of the transfer portion and upstream of the charging portion, which collects adhering materials and applies a voltage to prevent discharge threshold exceedance, thereby maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a collecting member is provided downstream of the transfer portion to collect residual toner, then residual toner collection is improved, but the collecting member accumulates toner and deteriorates its paper dust collection performance
Solution Approach 1:
The patent divides the collection function into two separate units: a charge neutralizer for paper dust collection and a collecting unit for residual toner collection. This segmentation prevents the collecting member from accumulating toner and deteriorating its paper dust collection performance, as each unit is dedicated to a specific collection task.
Solution Approach 2:
The charge neutralizer acts as an intermediary between the transfer portion and the collecting unit. It first neutralizes charges on the photosensitive drum surface, enabling effective paper dust collection before the residual toner is collected by the collecting unit. This intermediary function prevents charge accumulation that would otherwise interfere with paper dust collection.
2Reliability
If paper dust adheres to the photosensitive drum, then charge neutralization is reduced, but image defects occur due to reduced discharge in the charging process
Solution Approach 1:
The charge neutralizer is positioned to perform charge neutralization before the charging process. By pre-neutralizing charges on the photosensitive drum surface, including areas with adhered paper dust, the system ensures that subsequent charging operates under optimal conditions, preventing image defects caused by reduced discharge.
Solution Approach 2:
The charge neutralizer converts the harmful effect of charge accumulation (which causes image defects) into a benefit by actively neutralizing charges before they interfere with the charging process. This transforms a potential problem into a controlled condition that ensures consistent image quality.
3Reliability
If voltage is applied to the collecting unit to collect adhering material, then collection performance is improved, but discharge threshold may be exceeded causing image defects
Solution Approach 1:
The charge neutralizer performs preliminary charge neutralization before the collecting unit applies voltage for material collection. This preliminary anti-action prevents excessive charge accumulation that would occur if voltage were applied directly to a drum surface with accumulated adhering materials, thereby preventing discharge threshold exceedance and image defects.
Solution Approach 2:
By neutralizing charges before the collecting unit operates, the system prepares the drum surface in a state where subsequent voltage application for material collection will not cause discharge. This preliminary preparation ensures that collection performance is improved without exceeding the discharge threshold.
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 reduces the occurrence of image defects by effectively neutralizing charges and collecting adhering materials, ensuring consistent image quality in cleaner-less image forming systems.
Implementation Method 1
a charge neutralizer that neutralizes a charge on the surface of the image bearing member
Implementation Method 2
a collecting unit that has conductivity and collects an adhering material adhered to the surface of the image bearing member... a voltage application unit that applies a voltage of the predetermined polarity to the collecting unit
Implementation Method 3
the developing unit collects residual toner on the surface of the image bearing member after the toner image has been transferred
Data Source
AI summary
An image forming apparatus includes a charging unit that charges an image bearing member, a developing unit that forms a toner image on an latent image formed on the image bearing member, a transfer unit that transfers the toner image onto a transfer material, a charge neutralizer that neutralizes a charge of the image bearing member downstream of a transfer portion and upstream of a charging portion in a rotating direction of the image bearing member, a conductive collecting unit that collects a material adhering on the image bearing member downstream of the transfer portion and upstream of the charging portion, wherein the developing unit collects residual toner on the image bearing member, an voltage application unit sets a potential difference between the voltage applied to the collecting unit and the surface electric potential of the image bearing member not more than a discharge threshold.