Deboost Circuit for Precise Developing Voltage Control
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Solution Overview
Problem
Existing image forming apparatuses face challenges in minimizing the size of high-voltage power supply devices while maintaining high image quality, particularly due to difficulties in finely adjusting developing voltages as toner deterioration progresses.
Innovation Solution
The configuration includes a scorotron charger, a developing device, a voltage application circuit, a constant-voltage circuit, a deboost circuit, and control devices that allow for precise control of developing voltage by deboosting the grid voltage using a resistor and control transistor, enabling continuous and non-step adjustment of developing voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If a resistor is used to divide grid voltage to produce developing voltage, then the size of high-voltage power supply device is reduced, but the ability to minutely adjust developing voltage is lost
Solution Approach 1:
The patent replaces the simple resistor voltage division mechanism with an active control system using a control transistor. The control transistor dynamically adjusts the voltage drop across the resistor based on control signals, enabling continuous and precise adjustment of developing voltage while maintaining a compact circuit configuration.
Solution Approach 2:
The patent introduces dynamic control capability to the voltage generation system. The control transistor allows the developing voltage to be continuously adjusted in real-time based on operational requirements, transforming the static resistor division into a dynamic, programmable voltage control system.
2Ease of operation
If multiple separate power supply circuits are used for each developing device, then developing voltage can be independently controlled, but the overall device size increases
Solution Approach 1:
The patent creates a universal voltage generation architecture where a single grid voltage input is distributed to multiple developing devices through shared resistor-transistor control circuits. Each developing device receives independently controllable voltage through its own control transistor, achieving multi-functionality from a unified power supply structure.
Solution Approach 2:
The patent merges the voltage generation and control functions into integrated circuits shared across multiple developing devices. The resistor and control transistor form a shared control infrastructure that serves multiple devices simultaneously, reducing redundancy and overall device size while maintaining independent voltage control capability.
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 reduces the size of high-voltage power supply devices and allows for precise control of developing voltage, thereby achieving high image quality by ensuring uniform toner adherence across different colors.
Implementation Method 1
a deboost circuit which deboosts the grid voltage between the grid and the ground to generate a developing voltage being applied to the developing device. The deboost circuit has a circuit configuration in which a resistor and a control transistor are connected in series with each other, and deboosts the grid voltage by a voltage drop of the resistor to generate the developing voltage.
Data Source
AI summary
An image forming apparatus includes: a photosensitive member; a scorotron charger; a developing device; a voltage application circuit; a constant-voltage circuit; a first control device; a deboost circuit; and a second control device, wherein the deboost circuit has a circuit configuration in which a resistor and a control transistor are connected in series with each other, and deboosts the grid voltage by a voltage drop of the resistor to generate the developing voltage, and the second control device provides a control signal to the control transistor to control a current flowing in the resistor, thereby controlling the level of the developing voltage.