Developing Sleeve Voltage Control for Toner Attachment
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Solution Overview
Problem
In image forming apparatuses using electrophotographic techniques, toner deterioration leads to image defects due to unnecessary rotation of developing sleeves, and the shared developing power source configuration results in toner attachment to developing sleeves during stoppages, causing stripe images and increased toner consumption.
Innovation Solution
The apparatus includes a control unit that manages the potential difference between the surface potential of image bearing members and the developing voltage applied to developer bearing members, reducing the potential difference when the developing sleeves are stopped to minimize toner attachment, and optimizes the control based on environmental conditions and usage state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the developing sleeve is stopped to suppress toner deterioration, then toner life is extended, but toner attaches to the developing sleeve causing stripe images
Solution Approach 1:
The patent applies parameter changes by adjusting the fog-removing potential difference (Vback) to a lower level when the developing sleeve is stopped. This prevents toner attachment to the developing sleeve surface while maintaining the stopped state to reduce toner deterioration. The control unit dynamically changes the voltage parameter based on the rotation state, resolving the contradiction between extending toner life and preventing stripe images.
2Object-generated harmful factors
If the developing sleeve rotates continuously to prevent toner attachment, then stripe images are prevented, but toner deteriorates faster
Solution Approach 1:
The patent changes the voltage parameter (fog-removing potential difference) based on the rotation state. When the developing sleeve rotates, the normal fog-removing potential difference is applied. When stopped, the potential difference is reduced to prevent toner attachment. This dynamic parameter adjustment allows the system to prevent stripe images during rotation while extending toner life during stoppages.
3Object-generated harmful factors
If the fog-removing potential difference is applied at high level to prevent toner attachment, then stripe images are reduced, but toner consumption increases
Solution Approach 1:
The patent dynamically changes the fog-removing potential difference level based on whether the developing sleeve is rotating or stopped. By applying a lower potential difference during stoppages when toner attachment would occur anyway, the system reduces unnecessary toner consumption while maintaining effective stripe image prevention during active rotation periods.
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 attachment to developing sleeves, thereby minimizing image defects and extending toner life by reducing unnecessary rotation and optimizing power source management.
Implementation Method 1
the potential difference between a surface potential of an image bearing member and a voltage applied to a developer bearing member
Data Source
AI summary
An image forming apparatus includes first and second image forming units each having an image bearing member and an electrification portion. A developing bias application portion applies a common developing bias to first and second developer bearing members. A controller controls a second electrification bias application portion so as to have a voltage value of a second electrification bias applied to a second electrification portion in a first period different from that in a second period such that an absolute value of a potential difference between a surface potential of a second image bearing member and the common developing bias applied to the second developer bearing member in the first period is smaller than that in the second period.