Power Supply Apparatus Superimposing DC on AC Voltage
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Solution Overview
Problem
The existing power supply systems for image forming apparatuses have a limited adjustment range for direct current voltage, which restricts the variability of image density and gradation, especially when atmospheric conditions change, affecting the photosensitive member and toner adhesion.
Innovation Solution
A power supply apparatus that superimposes a direct current voltage on an alternating current voltage using a circuit configuration including a transformer, clamp circuit with a constant-voltage element and current limit element, and a direct current generation circuit, allowing for a wide adjustment range of the direct current voltage by varying the duty cycle of the input pulse signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional power supply system is used, then the circuit structure is simple, but the adjustment range of direct current voltage is limited
Solution Approach 1:
The power supply circuit is segmented into distinct functional modules: an alternating current generation circuit (with transformer and pulse signal input), a clamp circuit (with constant-voltage element and current limit element), and a direct current generation circuit. This segmentation allows each module to be optimized independently, enabling wide adjustment of direct current voltage through duty cycle control while maintaining manageable circuit complexity through modular design.
Solution Approach 2:
The invention introduces dynamic control capability by allowing the duty cycle of the input pulse signal to be varied, which dynamically adjusts the direct current voltage output. The clamp circuit with switchable constant-voltage elements provides dynamic voltage clamping, enabling the system to adapt to different operating conditions and achieve a wide adjustment range for image density control.
2Adaptability or versatility
If the adjustment range of direct current voltage is widened, then the image density variability is improved, but the circuit complexity increases
Solution Approach 1:
The invention achieves wide adjustment of image density variability by changing the duty cycle parameter of the input pulse signal, which directly controls the direct current voltage magnitude. The clamp circuit parameters (constant-voltage element values) can also be adjusted to modify the voltage clamping characteristics, providing additional parameter control for optimizing image density range without requiring complete circuit redesign.
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 enables a broader range of direct current voltage adjustment, enhancing the variability of image density and gradation, improving the image forming process by maintaining desired image quality across different conditions.
Implementation Method 1
An alternating current generation circuit has a transformer and is configured to generate an alternating current voltage in accordance with a pulse signal input to the transformer
Implementation Method 2
A clamp circuit has a constant-voltage element and a current limit element connected in series
Implementation Method 3
The direct current generation circuit converts, into a direct current voltage, a current that flows from the clamp circuit via the ground
Data Source
AI summary
An alternating current generation circuit has a transformer and generates an alternating current voltage in accordance with a pulse signal input to the transformer. A clamp circuit has a constant-voltage element and a current limit element connected in series between the transformer, an output end of the alternating current voltage, and a ground. A direct current generation circuit generates a direct current voltage in accordance with a duty cycle of the input pulse signal. The direct current generation circuit converts, into a direct current voltage, a current that flows from the clamp circuit via the ground, and superimposes the direct current voltage on the alternating current voltage, and a voltage obtained by superimposing the direct current voltage on the alternating current voltage is output from the output end.