Toner Agitation Control for Image Quality in Developing Devices
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Solution Overview
Problem
Image forming apparatuses face issues with inaccurate toner detection due to changing bulk density, leading to inappropriate toner supply and potential overflow, and existing solutions like developing agitation are not always necessary, causing toner deterioration.
Innovation Solution
An image forming apparatus with a controller that manages toner supply and agitation based on threshold values and sensor data, performing agitation only when necessary to maintain accurate toner levels and prevent bulk density changes, thereby reducing unnecessary agitation and toner deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If developing agitation is performed at prescribed timing to prevent bulk density changes, then toner detection accuracy is improved, but toner deterioration occurs due to excessive agitation
Solution Approach 1:
The patent changes the control parameter from fixed timing agitation to conditional agitation based on bulk density detection. The system detects bulk density changes and only performs agitation when the change exceeds a threshold, thereby avoiding unnecessary agitation and preventing toner deterioration while maintaining detection accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where the toner sensor continuously monitors bulk density, and the controller adjusts agitation timing based on detected changes. This feedback loop ensures agitation is performed only when necessary to maintain accurate toner levels, resolving the contradiction between detection accuracy and toner preservation.
2Measurement precision
If developing agitation is performed frequently to maintain accurate toner levels, then toner detection accuracy is improved, but image quality deteriorates due to toner degradation
Solution Approach 1:
The system transitions from fixed-frequency agitation to variable-frequency agitation based on actual bulk density changes. By monitoring the bulk density parameter and agitating only when changes exceed thresholds, the system maintains detection accuracy while minimizing toner degradation that would affect image quality.
Solution Approach 2:
Instead of performing agitation at every prescribed timing, the system applies partial action by agitating only when bulk density changes warrant it. This selective approach maintains sufficient toner level accuracy for detection while avoiding excessive agitation that would degrade toner and compromise image quality.
3Measurement precision
If developing agitation is performed based on toner sensor comparison to ensure accurate detection, then toner level accuracy is improved, but unnecessary agitation occurs leading to toner deterioration
Solution Approach 1:
The patent changes the control logic from comparing toner sensor values to monitoring bulk density changes. By detecting bulk density variations directly and agitating only when changes exceed thresholds, the system achieves accurate toner level detection without the unnecessary agitation that would deteriorate toner condition.
Solution Approach 2:
The system uses the toner sensor to self-monitor bulk density changes and automatically determines when agitation is needed. This self-service approach ensures agitation is performed only when the toner level requires it, maintaining detection accuracy while preserving toner quality through minimal necessary agitation.
Data Source
AI summary
In an image forming apparatus, it is determined whether a shortage amount of toner in a developing device is greater than a threshold value of 4 g or not, when the power is turned on to start operation. As a result, if the shortage amount of toner in the developing device is greater than 4 g, an agitating operation is executed to agitate toner in the developing device prior to a printing operation. If the shortage amount is smaller than 4 g, the agitating operation is not executed. Then, a printing command is received, and if the agitating operation is not performed, control of an operation of supplying toner is started with a delay of at least for the time required for the agitating operation, after the printing operation is started.