Charge Removal Light Control for Carrier Shift Suppression
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Solution Overview
Problem
In electrophotographic image forming apparatuses, the carrier shift phenomenon occurs during the two-component developing method, where the carrier in the magnetic brush shifts to the photosensitive member's surface, leading to development failures such as fog and rear end accumulation, and it is challenging to improve carrier shift without causing development failures.
Innovation Solution
The introduction of a previous charge removal light-emitting portion that applies charge removal light to a specific target region on the photosensitive member, including the magnetic brush contact area and the region between this area and the transfer position, helps to suppress carrier shift while minimizing development failures by adjusting the light intensity based on the toner image density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If charge removal light is applied to suppress carrier shift, then carrier shift is reduced, but development failures such as fog and rear end accumulation may occur
Solution Approach 1:
The patent applies charge removal light selectively to specific regions (non-image areas) of the photosensitive member rather than uniformly across the entire surface. This localized application suppresses carrier shift in regions where it occurs without affecting image areas, thereby preventing development failures like fog while maintaining image quality.
Solution Approach 2:
The patent uses partial action by applying charge removal light only to non-image regions rather than the entire photosensitive member surface. This partial application is sufficient to suppress carrier shift in the critical areas without causing excessive light exposure that would lead to development failures in image regions.
2Reliability
If neutralization light intensity is increased to improve transferability, then transferability improves, but image quality may deteriorate
Solution Approach 1:
The patent controls neutralization light intensity differently for image and non-image regions. Higher intensity is applied to non-image areas to improve transferability, while lower or no intensity is applied to image areas to preserve image quality. This spatially differentiated control resolves the contradiction between transferability and image quality.
3Reliability
If charge removal is applied to the entire photosensitive member surface, then carrier shift is suppressed, but toner image density and quality deteriorate
Solution Approach 1:
The patent selectively applies charge removal light only to non-image regions of the photosensitive member, preserving the charge distribution and toner adhesion in image regions. This localized approach suppresses carrier shift where it occurs without affecting toner image density and quality in the printed areas.
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 approach effectively reduces carrier shift occurrences while preventing development failures, ensuring stable image formation by controlling the charge removal light emission in accordance with the toner image density, thereby maintaining image quality and reducing carrier accumulation on the photosensitive member.
Implementation Method 1
a light-emitting portion configured to apply charge removal light to a charge removal target region of the effective outer circumferential surface of the photosensitive member
Data Source
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AI summary
In the case where development is performed by a two-component developing method, a previous charge removal light-emitting portion (44) applies charge removal light to a first charge removal target region (413) of an effective outer circumferential surface (410) of a photosensitive member (41) on which effective outer circumferential surface (410) an electrostatic latent image can be formed. The first charge removal target region (413) includes a part of a magnetic brush contact region (411) of the effective outer circumferential surface (410) and a region of the effective outer circumferential surface (410) between the magnetic brush contact region (411) and a transfer position (412) of a toner image.