Toner Detection Circuit Layout to Reduce Stray Capacitance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrophotographic image forming apparatuses face a decrease in accuracy of detecting the remaining amount of developer due to stray capacitance affecting the current detection between electrodes, leading to inaccurate toner detection.
Innovation Solution
The image forming apparatus is designed with a first and second electrode within the developer accommodating portion, where a first substrate applies voltage and a second substrate detects the detection current, with the second substrate positioned closer to the electric contact than the first substrate, reducing the influence of stray capacitance and crosstalk noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the signal line connects the electrode and the current detection circuit, then the remaining amount of toner can be detected, but stray capacitance between the signal line and frame or another signal line decreases the current detection accuracy
Solution Approach 1:
The patent extracts the current detection circuit from the first substrate and places it on a separate second substrate. This physical separation removes the source of stray capacitance (the first substrate with its circuitry and frame connections) from proximity to the signal line, thereby eliminating the harmful capacitive coupling that degrades measurement precision.
Solution Approach 2:
The patent introduces a dedicated signal line as an intermediary pathway between the electrode and the current detection circuit. By providing a controlled, isolated signal transmission path separate from other circuits and frame structures, the signal line minimizes unwanted capacitive interactions while maintaining electrical connectivity for accurate toner amount detection.
2Device complexity
If the first substrate and second substrate are integrated, then the device structure is simplified, but the space required for signal lines increases
Solution Approach 1:
The patent divides the device into two separate substrates: the first substrate for voltage application and the second substrate for current detection. This segmentation allows each substrate to be optimized for its specific function with minimal signal line requirements, reducing the total space needed compared to a fully integrated design where all circuits would require extensive interconnections.
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 enhances the accuracy of detecting the remaining amount of developer, allowing for a more precise toner detection and contributes to downsizing the apparatus by minimizing the space required for signal lines, thus improving the overall performance and reducing the device's size.
Implementation Method 1
two electrodes are provided in the toner container to form a capacitance, and a current detection circuit connected to one of the electrodes detects the current between the electrodes to detect and acquire the remaining amount of toner
Data Source
AI summary
An image forming apparatus includes an image bearing member, a developer accommodating portion, a first electrode and a second electrode provided within the developer accommodating portion, a first electric contact, a second electric contact, a first substrate, and a second substrate configured to detect a detection current flowing between the first electrode and the second electrode. A minimum distance between the second substrate and the second electric contact is shorter than a minimum distance between the first substrate and the second electric contact, and wherein a distance between the second substrate and the second electric contact is shorter than a distance between the first substrate and the second electric contact in at least one of the first and second directions.