Inductance Sensor Voltage Control for Toner Density
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Solution Overview
Problem
Conventional toner density control methods in image forming apparatuses using inductance sensors are prone to erroneous detection due to changes in bulk density caused by frictional charge and environmental factors, leading to inconsistent toner supply and reduced productivity, especially during large image ratio variations.
Innovation Solution
An image forming apparatus with an inductance sensor that adjusts its control voltage based on the image ratio, using a calculation portion to determine the correct toner density and implementing a controller to manage the developer supply, ensuring accurate toner density control by adjusting the magnetic field strength of the inductance sensor in response to varying image ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an inductance sensor is used to detect toner density, then toner density control is achieved, but erroneous detection occurs due to changes in bulk density caused by frictional charge and environmental factors
Solution Approach 1:
The patent applies parameter changes by adjusting the control voltage of the inductance sensor based on the detected image ratio. When the image ratio exceeds a predetermined threshold, the control voltage is increased to compensate for the bulk density changes caused by frictional charge. This dynamic parameter adjustment ensures that the inductance sensor maintains accurate toner density detection despite variations in developer bulk density, thereby resolving the contradiction between measurement precision and reliability.
2Measurement precision
If toner is supplied to maintain constant inductance sensor output, then toner density control is maintained, but the TD ratio increases and frictional charge decreases when image ratios are large
Solution Approach 1:
The patent implements dynamics by making the toner supply control adaptive rather than static. Instead of maintaining a fixed control voltage, the system dynamically adjusts the control voltage based on the image ratio. When large image ratios are detected, the control voltage is increased to prevent excessive toner supply that would otherwise occur due to bulk density changes. This dynamic control prevents the vicious cycle of increasing TD ratio and decreasing frictional charge, thereby maintaining both toner density control accuracy and image formation productivity.
Solution Approach 2:
The patent employs feedback control by continuously monitoring the image ratio and using this information to adjust the inductance sensor's control voltage. The system creates a feedback loop where the image ratio detection result feeds back to modify the sensor operating conditions. This feedback mechanism ensures that the toner density control adapts to changing image conditions, preventing erroneous detection and maintaining optimal toner supply efficiency throughout the image formation process.
3Measurement precision
If patch detection ATR control is used to correct density control, then detection accuracy improves, but productivity is greatly lowered due to frequent patch image measurement requirements
Solution Approach 1:
The patent applies preliminary action by proactively adjusting the inductance sensor's control voltage based on the detected image ratio before erroneous detection can occur. Instead of waiting for density control errors to develop and then correcting them through patch detection, the system preemptively modifies the sensor operating parameters when large image ratios are detected. This preliminary adjustment prevents the need for frequent patch image measurements and corrections, thereby maintaining both high detection accuracy and productivity without the interruptions associated with patch detection ATR control.
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 approach stabilizes toner density control, reducing erroneous detection and maintaining image quality across varying image ratios, thereby enhancing the productivity and reliability of the image forming process.
Implementation Method 1
an inductance sensor configured to output a voltage value corresponding to a density of the toner in the developer in the developing unit
Implementation Method 2
a voltage controller configured to control an absolute value of an adjusting voltage value to a second voltage value smaller than a first voltage value in a case where an averaged image ratio of a predetermined number of the electrostatic images is a second image ratio larger than a first image ratio. The adjusting voltage value is a voltage value for adjusting a magnitude of a magnetic field of the inductance sensor
Data Source
AI summary
An image forming apparatus includes a calculation portion that calculates an image ratio of the electrostatic image to be formed. A controller controls developer supply from a developer supplier to a developing unit based on the toner density output of an inductance sensor. An adjustment portion adjusts the density of the toner output from the toner density detection portion to a higher value in a case where the image ratio calculated by the calculation portion is higher than a predetermined image ratio.