Toner Charge Prediction for Image Density Control
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Solution Overview
Problem
The existing electrophotographic image forming apparatuses face challenges in stabilizing image density due to fluctuations in toner particle charge, which are influenced by environmental factors and the T/C ratio of toner to carrier particles, leading to downtime and inaccuracies in toner supply control.
Innovation Solution
An image forming apparatus with a controller that determines the toner charge amount based on consumption, supply, and detection, forming a measurement image to update prediction expressions for real-time control, adjusting toner supply to maintain target image density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If feedback control is performed by forming a measurement image and measuring toner adhesion, then image density control is achieved, but downtime increases due to the measurement process
Solution Approach 1:
The system performs preliminary action by predicting the toner charge amount before actual image formation using prediction expressions. This allows the control system to anticipate and adjust for charge variations proactively, rather than waiting to measure actual toner adhesion after image formation, thereby reducing downtime while maintaining density control accuracy
Solution Approach 2:
The patent replaces the mechanical measurement system (forming measurement images and physically measuring toner adhesion) with a computational prediction system. By substituting physical measurement with mathematical prediction based on toner supply and consumption data, the system eliminates the time-consuming measurement step while maintaining control precision
2Device complexity
If constant time constants are used for predicting toner charge amount, then prediction is simplified, but accuracy decreases when environmental conditions change
Solution Approach 1:
The system applies dynamics by making the prediction expressions adaptive rather than static. The time constants and prediction parameters are dynamically adjusted based on actual measurement results and environmental conditions. This allows the system to maintain high prediction accuracy across varying conditions while managing complexity through structured adaptation mechanisms
Solution Approach 2:
The patent implements parameter changes by allowing the prediction expressions to modify their parameters (time constants, coefficients) based on measured data and environmental conditions. This enables the system to adapt to changing conditions without requiring a completely different prediction model, balancing accuracy improvement with manageable complexity
3Stability of the object's composition
If toner supply control is performed based on measurement results, then image density is stabilized, but the charge amount adjustment lags behind actual changes
Solution Approach 1:
The system performs preliminary action by predicting toner charge amount changes before they fully manifest in actual image formation. By using prediction expressions that anticipate charge variations based on toner supply and consumption patterns, the system can adjust toner supply proactively, reducing the lag between actual charge changes and control response while maintaining density stability
Data Source
AI summary
Provided is an image forming apparatus, including a photosensitive member, a latent image forming unit configured to form an electrostatic latent image on the photosensitive member, a developing unit configured to store developer containing toner and to develop the electrostatic latent image on the photosensitive member using the developer, a detector configured to detect an amount of the toner stored in the developing unit, and a supplying unit configured to supply toner to the developing unit.