Voltage Divider for Multi-Pass Image Forming Apparatus
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Solution Overview
Problem
Conventional image forming apparatuses experience cross contamination of toners, particularly from black toner to other colors, which affects the quality of printed images, especially when using the multi-pass type method with fixed developing devices.
Innovation Solution
The apparatus employs a power supply and voltage divider system to manage voltages applied to developing devices, where one device is connected to a high voltage for development, and others are either disconnected or supplied with a lower voltage to prevent toner development, with the K developing device being grounded to minimize contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If all developing devices are supplied with high voltage simultaneously, then all toners can be developed, but cross contamination occurs between different color toners
Solution Approach 1:
The power supply system is segmented to supply high voltage to only one developing device at a time through a switching unit, while other developing devices receive different voltage levels (second voltage or third voltage) through the voltage divider, preventing cross contamination while maintaining development capability when needed
Solution Approach 2:
Different voltage levels are applied to different developing devices based on their operational state: the active developing device receives high voltage for development, while inactive devices receive second voltage (for preventing development) or third voltage (with absolute value less than second voltage), creating local quality differences that prevent cross contamination
2Object-affected harmful factors
If high voltage is applied to prevent toner development in inactive developing devices, then cross contamination is prevented, but energy consumption increases
Solution Approach 1:
The voltage level parameter is changed based on the operational state of each developing device: high voltage for active devices, second voltage (intermediate level) for some inactive devices, and third voltage (lowest absolute value) for other inactive devices, optimizing the balance between cross contamination prevention and energy consumption
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 reduces cross contamination, ensuring high-quality image printing by maintaining the K developing device's electric potential at a lower level, thereby minimizing black toner movement and contamination, even when not participating in development.
Implementation Method 1
a voltage divider for supplying some of the other developing devices that are not connected to the power supply with a second voltage for preventing toner development and supplying any other remaining developing device with a third voltage
Data Source
AI summary
An image forming apparatus includes a plurality of developing devices to develop toners of different colors on an image carrier; a power supply to supply the plurality of developing devices with a first voltage to develop the toners on the image carrier; a switching unit to connect the power supply to one of the plurality of developing devices; and a voltage divider to supply some of the other developing devices that are not connected to the power supply with a second voltage to prevent toner development and to supply any other remaining developing device with a third voltage, an absolute value of which is less then an absolute value of the second voltage.