Dynamic Charge Elimination Control for Image Forming Apparatus
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Solution Overview
Problem
In image forming apparatuses using the electrophotographic method, residual potential on the photosensitive member can lead to charge elimination unevenness, affecting image quality due to toner adherence on the charge eliminating unit, reducing its light irradiation capability and causing image defects.
Innovation Solution
The apparatus includes a switching unit that adjusts the light amount of the second charge eliminating unit based on usage, ensuring it exceeds the first charge eliminating unit's light amount when the second image forming portion reaches a predetermined usage level, thereby maintaining consistent charge elimination across the photosensitive members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the charge eliminating unit irradiates light onto the photosensitive member to eliminate residual charge, then the electric potential on the photosensitive member surface is reduced to a predetermined level, but toner adheres to the charge eliminating unit causing decreased light irradiation capability and charge elimination unevenness
Solution Approach 1:
The patent divides the charge elimination function into multiple independent charge eliminating units (first charge eliminating unit and second charge eliminating unit), each serving specific image forming portions. This segmentation allows independent control and maintenance of each unit, preventing toner adhesion from affecting the entire system's charge elimination capability.
Solution Approach 2:
The patent dynamically adjusts the light amount parameter of the second charge eliminating unit based on usage amount. When the usage amount of the second image forming portion reaches a predetermined threshold, the light amount is switched to a value greater than the first charge eliminating unit's light amount, compensating for toner adhesion effects and maintaining consistent charge elimination performance.
2Manufacturing precision
If toner adheres to the charge eliminating unit during image formation, then the light amount irradiated onto the photosensitive member decreases, but this causes charge elimination unevenness and image quality degradation
Solution Approach 1:
The patent implements a feedback control mechanism where the light amount of the second charge eliminating unit is adjusted based on the usage amount of the second image forming portion. When usage reaches a predetermined level, the system increases the light amount to compensate for toner adhesion, ensuring consistent charge elimination and maintaining image quality.
Solution Approach 2:
The patent makes the light amount parameter dynamic rather than fixed. The second charge eliminating unit's light amount is switched between different values based on usage conditions, allowing the system to adapt to toner adhesion effects and maintain optimal charge elimination performance throughout the device's operation lifecycle.
3Productivity
If multiple image forming portions share a common intermediate transfer member, then productivity is improved through efficient resource utilization, but charge elimination uniformity becomes difficult to maintain across different usage amounts
Solution Approach 1:
The patent assigns different light amounts to different charge eliminating units based on their specific usage conditions. The second charge eliminating unit receives a greater light amount when its usage reaches a predetermined level, allowing each unit to be optimized for its local requirements while sharing the common intermediate transfer member, thus maintaining charge elimination uniformity across different usage scenarios.
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 effectively suppresses charge elimination unevenness, maintaining image quality by ensuring consistent light exposure to the photosensitive members, reducing the occurrence of afterimages and improving overall image formation.
Implementation Method 1
a first charge eliminating unit which eliminates a charge from the first photosensitive member by exposing the first photosensitive member to light after a toner image formed by the first developing unit is transferred onto the intermediate transfer member
Data Source
AI summary
An image forming apparatus includes a rotatable intermediate transfer member; a first image forming portion having a first photosensitive member which rotates, a first developing unit, and a first charge eliminating unit; a second image forming portion that is located on a downstream side of the first image forming portion in a rotational direction of the intermediate transfer member, and that has a second photosensitive member which rotates, a second developing unit, and a second charge eliminating unit; a transfer unit; and a switching unit that switches a light amount of the second charge eliminating unit when a usage amount of the second image forming portion reaches a predetermined amount to a value that is greater than a light amount of the first charge eliminating unit when a usage amount of the first image forming portion reaches the predetermined amount.