Common Power Source for Developing and Transfer Voltage in Image Forming Apparatus
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in downsizing and cost reduction while maintaining stable transfer roller cleaning performance, as they require separate power sources for cleaning voltage, which can disrupt the surface potential of the photosensitive member and affect transfer efficiency.
Innovation Solution
An image forming apparatus with a common power source for both developing and transfer voltages, controlled by a controller to execute cleaning operations using the same polarity voltage during non-image forming periods, allowing for effective toner transfer from the transfer roller to the photosensitive member without an individual power source for cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate power source is provided for cleaning voltage, then transfer roller cleaning performance is stable, but device complexity and cost increase
Solution Approach 1:
The patent merges the power source for cleaning voltage with the existing developing voltage power source. The controller applies the developing voltage to the transfer roller during cleaning operations, eliminating the need for a separate cleaning power source. This reduces device complexity and cost while maintaining cleaning functionality through the shared power source.
Solution Approach 2:
The developing voltage power source is made multi-functional by using it for both developing operations and cleaning operations. The controller dynamically assigns the power source to different functions based on operational mode, allowing a single power source to serve multiple purposes and reducing overall system complexity.
2Reliability
If cleaning voltage is applied during image forming operation, then transfer roller is cleaned, but surface potential of photosensitive member changes
Solution Approach 1:
The controller performs cleaning operations during non-image forming periods (such as idle time between sheets or during post-processing), rather than during active image forming. This preliminary timing ensures that cleaning occurs when it does not interfere with the surface potential stability required for image formation, while still maintaining regular cleaning of the transfer roller.
Solution Approach 2:
The cleaning operation is executed periodically during non-image forming intervals rather than continuously. The controller alternates between image forming operations and cleaning operations, applying cleaning voltage to the transfer roller during idle periods when the photosensitive member is not being used for image formation, thus maintaining surface potential stability during critical image forming phases.
3Device complexity
If developing voltage is used for cleaning operation, then power source is reduced, but voltage value must be changed to maintain cleaning performance
Solution Approach 1:
The controller dynamically adjusts the voltage value applied to the transfer roller during cleaning operations based on the specific cleaning requirements. By making the voltage value changeable and adaptable, the system can optimize cleaning performance when using the shared developing voltage power source, allowing the same power source to effectively serve both developing and cleaning functions with different voltage parameters.
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 solution enables downsizing and cost reduction of the image forming apparatus while maintaining stable cleaning performance by using a common power source for both developing and transfer voltages, ensuring effective toner transfer and reducing paper back contamination.
Implementation Method 1
a voltage of the same polarity as the normal charge polarity of the toner is applied to the transfer roller, so that the toner deposited on the transfer roller is transferred onto the photosensitive member (reverse transfer)
Data Source
AI summary
An image forming apparatus includes a rotatable photosensitive member, a charging member, an exposure unit, a developing member, a developing voltage applying portion, a transfer member, a first transfer voltage applying portion, a second transfer voltage applying portion, a common power source, and a controller. The controller carries out control so as to execute an image forming operation, and a non-image forming operation and so as to execute, as the non-image forming operation, a cleaning operation. The controller controls a change in output of the common power source so that a value of a voltage applied from the developing voltage applying portion to the developing member during the cleaning operation is made different from a value of a voltage applied from the developing voltage applying portion to the developing member during formation of the toner image.