High Voltage Power Supply Capacitance Variation Feedback
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Solution Overview
Problem
Conventional methods for correcting developing bias voltage in image forming apparatuses fail to accurately account for environmental changes, leading to potential excess or deficiency in developer supply and subsequent image quality deterioration due to incorrect determination of the distance between the photoreceptor and developing roller.
Innovation Solution
A high voltage power supply system comprising a developer carrier, image carrier, developing control unit, load detection unit, variation detection unit, and voltage correction unit, which detects capacitance variations and adjusts the developing bias voltage accordingly to correct for changes in distance and environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the developing bias voltage is corrected based on the detected capacitance value, then the distance between photoreceptor and developing roller can be compensated, but the correction becomes inaccurate when environmental conditions (humidity, atmospheric pressure) change the capacitance
Solution Approach 1:
The system continuously monitors capacitance changes between the photoreceptor and developing roller, and automatically adjusts the developing bias voltage in response to detected variations. This feedback mechanism ensures that the developing voltage is dynamically corrected based on actual operational conditions, maintaining accurate distance compensation despite environmental fluctuations.
Solution Approach 2:
The invention changes the development approach from using absolute capacitance values to using capacitance variation (ΔC) as the correction parameter. By detecting changes in capacitance rather than fixed values, the system becomes insensitive to environmental conditions like humidity and atmospheric pressure that affect absolute capacitance measurements, thereby improving the reliability of distance determination.
2Productivity
If the developing bias voltage is increased to move developer longer distance, then developer supply to photoreceptor is improved, but excess developer may be supplied causing image quality deterioration
Solution Approach 1:
The system uses real-time capacitance variation detection to provide feedback on the actual distance between photoreceptor and developing roller. This feedback enables precise control of developer transport distance, allowing the system to increase voltage only when and where needed, thereby improving developer supply efficiency without causing excess supply that would deteriorate image quality.
Solution Approach 2:
The developing bias voltage is made dynamic rather than fixed, adjusting in real-time based on detected capacitance variations. This dynamic adjustment allows the system to optimize developer transport for each specific operational condition, ensuring adequate supply when distance increases while preventing over-supply when distance is normal, thus maintaining image quality.
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 system effectively corrects the developing bias voltage, ensuring appropriate developer supply and reducing image quality deterioration by accurately accounting for environmental and positional changes, thereby maintaining consistent image quality.
Implementation Method 1
The load detection unit detects capacitance between the developer carrier and the image carrier
Implementation Method 2
The developing control unit applies a developing bias voltage, which is obtained by superimposing a direct voltage and an alternating voltage, to the developer carrier and generates a potential difference between the developer carrier and the image carrier, and thereby supplies the developer to the image carrier
Data Source
AI summary
A high voltage power supply includes a developer carrier, an image carrier, a developing control unit, a load detection unit, a variation detection unit, and a voltage correction unit. The developing control unit applies a developing bias voltage to the developer carrier and thereby supplies the developer to the image carrier and develops an electrostatic latent image. The variation detection unit detects the variation in capacitance between the developer carrier and the image carrier detected by the load detection unit. The voltage correction unit corrects the developing bias voltage by decreasing the developing bias voltage as the variation increases, and increasing the developing bias voltage as the variation decreases.