Image Forming Control for Low-Coverage Toner Deterioration
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Solution Overview
Problem
Toner deterioration in developer containers of image forming apparatuses leads to image failures such as fogging, primarily due to toner flowing and stirring during low-image coverage operations, which accelerates when toner remains unused in the container.
Innovation Solution
The image forming apparatus employs a low-image coverage support mode that adjusts the peripheral velocities of the photosensitive drum and developing roller to ⅔ of normal operation and increases the exposure intensity, reducing the opportunity for toner rubbing and enhancing latent image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the photosensitive drum rotates at normal peripheral velocity with normal exposure intensity, then image formation efficiency is high, but toner deterioration accelerates due to excessive toner rubbing and stirring in the developer container
Solution Approach 1:
The patent applies dynamics by making the rotation speed of the photosensitive drum variable rather than fixed. The control unit dynamically adjusts the rotation speed based on the operation mode: reducing it to ⅔ of the normal speed during low-image coverage operations to minimize toner rubbing, while maintaining normal speed during high-image coverage operations to ensure efficient image formation. This dynamic adjustment resolves the contradiction between productivity and toner quality stability.
Solution Approach 2:
The patent changes the parameter of peripheral velocity of the photosensitive drum based on operation mode. During low-image coverage operations, the peripheral velocity is reduced to ⅔ of the normal value, which reduces the mechanical rubbing and stirring of toner in the developer container, thereby preventing toner deterioration. This parameter change allows the system to maintain both efficiency and toner quality under different operating conditions.
2Quantity of substance
If the exposure intensity is increased to compensate for low-image coverage, then toner consumption increases, but the opportunity for toner rubbing and deterioration remains high
Solution Approach 1:
The system dynamically adjusts both rotation speed and exposure intensity based on operation mode. During low-image coverage operations, the rotation speed is reduced to ⅔ while exposure intensity is increased to 1.5 times the normal level. This coordinated dynamic adjustment ensures that toner is consumed at an appropriate rate while minimizing the mechanical rubbing that causes deterioration, resolving the contradiction between increasing toner consumption and maintaining toner quality.
Solution Approach 2:
The patent changes multiple parameters simultaneously: reducing peripheral velocity to ⅔ and increasing exposure intensity to 1.5 times normal levels during low-image coverage operations. This multi-parameter change creates a balanced condition where toner is sufficiently consumed to prevent stagnation-related deterioration, while the reduced rotation speed minimizes mechanical rubbing. This resolves the contradiction between toner consumption and toner quality stability.
3Reliability
If the photosensitive drum rotates at reduced peripheral velocity, then toner rubbing and deterioration are minimized, but image formation speed decreases
Solution Approach 1:
The system applies dynamics by adjusting the rotation speed of the photosensitive drum based on the specific operation mode. During low-image coverage operations, the rotation speed is reduced to ⅔ of normal speed to minimize toner rubbing and deterioration. During high-image coverage operations, the normal rotation speed is maintained to ensure fast image formation. This dynamic, mode-dependent adjustment resolves the contradiction between toner quality stability and image formation speed.
Solution Approach 2:
The control unit preliminarily determines the operation mode (low-image coverage or high-image coverage) before initiating image formation. Based on this preliminary classification, it pre-adjusts the rotation speed of the photosensitive drum to the appropriate level. This preliminary action ensures that the correct rotation speed is applied from the start of the operation, optimizing both toner quality protection and image formation efficiency without delays.
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 reduces toner deterioration by increasing the exposure amount on the photosensitive drum, thereby increasing toner consumption and preventing image failures like fogging, even with low-image coverage operations.
Implementation Method 1
a charging member configured to come into contact with the image bearing member to charge a surface of the image bearing member; a charging voltage application portion configured to apply a charging voltage to the charging member
Implementation Method 2
an exposure unit configured to expose the surface of the image bearing member to form an electrostatic latent image on the surface of the image bearing member
Implementation Method 3
a developer bearing member configured to bear the developer contained in the developer containing portion, the developer bearing member being configured to rotate and supply the developer to the surface of the image bearing member
Data Source
AI summary
In an image forming apparatus, in which: a charging member charges an image bearing member; an exposure unit exposes a surface of the image bearing member to develop an electrostatic latent image; and a developer image on the image bearing member is transferred onto a recording material. A control portion is capable of executing a first operation mode for rotating the image bearing member at a first peripheral velocity, the first operation mode being a mode in which the exposure unit exposes the surface of the image bearing member with a first exposure intensity, and a second operation mode for rotating the image bearing member at a second peripheral velocity lower than the first peripheral velocity, the second operation mode being a mode in which the exposure unit exposes the surface of the image bearing member with a second exposure intensity higher than the first exposure intensity.