Prevention Bias Generator Circuit for Developer Scattering Control
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Solution Overview
Problem
The existing prevention bias generator circuits in image forming apparatuses often fail to maintain a sufficient potential difference between the prevention bias and the developing DC bias, leading to potential scattering of developer, especially when the developing AC bias varies due to environmental or usage-related factors.
Innovation Solution
A prevention bias generator circuit that holds the peak value of the developing bias to output a prevention bias, ensuring it has the same polarity as the developing DC bias and maintaining a potential difference greater than a predetermined value, by using a configuration with a resistor, diode, and capacitor to rectify and boost the developing bias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a voltage doubling rectifier circuit is used to generate prevention bias from developing AC bias, then the prevention bias magnitude is sufficient, but the potential difference between prevention bias and developing DC bias becomes insufficient when developing AC bias varies
Solution Approach 1:
The invention introduces a feedback mechanism by detecting the actual developing bias voltage and using this detected value to dynamically adjust the prevention bias voltage. The detection circuit monitors the developing bias, and the control circuit uses this information to generate a prevention bias that maintains a sufficient potential difference regardless of variations in the developing AC bias, thus resolving the contradiction between sufficient prevention bias magnitude and stable potential difference.
Solution Approach 2:
The invention changes the parameter basis for generating prevention bias from a fixed relationship with developing AC bias to a dynamic relationship based on detected developing bias voltage. By using the detected developing bias as the reference parameter and applying a predetermined ratio, the system adapts to variations in developing conditions and maintains reliable potential difference, solving the contradiction between power sufficiency and reliability stability.
2Adaptability or versatility
If the developing AC bias varies due to environmental or usage factors, then the developing process adapts to different conditions, but the prevention bias becomes insufficient to prevent developer scattering
Solution Approach 1:
The detection circuit continuously monitors the actual developing bias voltage, providing real-time feedback on the developing conditions. This feedback enables the control circuit to adjust the prevention bias dynamically, ensuring that developer scattering prevention remains reliable even when the developing AC bias varies due to environmental or usage factors, thus maintaining both adaptability and reliability.
Solution Approach 2:
The system uses its own developing bias signal as the basis for generating the prevention bias. By detecting the developing bias and using it to control the prevention bias generation, the system serves itself, automatically adapting to changing conditions without external intervention, thereby maintaining reliable developer scattering prevention across varying operating conditions.
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 ensures the prevention bias is consistently greater than the developing DC bias, effectively preventing developer scattering across a wider range of developing bias settings, enhancing the reliability of the image forming process.
Implementation Method 1
A prevention bias generator circuit that holds the peak value of the developing bias to output a prevention bias
Implementation Method 2
applying a bias (hereinafter, 'prevention bias') to the prevention electrode and thereby applying a force on the developer in the direction toward the developing sleeve
Data Source
AI summary
A developing device for developing an electrostatic latent image on an image carrier by using developer includes a developing bias output unit configured to output a developing bias generated by superimposing an AC bias on a DC bias, a developing sleeve supplied with the developing bias output from the developing bias output unit, and a prevention bias generator unit configured to generate a prevention bias by holding a peak value of the developing bias of the superimposed AC bias and DC bias, with the prevention bias suppressing scattering of developer carried by the developing sleeve. In addition, an electrode is disposed at a position opposing the developing sleeve and configured to output the prevention bias.