Developer Carrier Reverse Rotation for Toner Aggregation
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Solution Overview
Problem
In image forming apparatuses using an electro-photographic system, continuous printing of images with low image area rates leads to toner aggregation at the developer lifting section, causing abnormal images with white lines or bands, as the opportunity for reverse rotation to remove aggregated toner is infrequent, especially during long printing sessions without stopping the developer carrier.
Innovation Solution
An image forming apparatus with a controller that initiates a forced drive stop sequence to stop the developer carrier rotation, reverse rotate it for a prescribed time, and then resume printing after a set period, resetting the sheet count, and optionally allowing user-defined thresholds and sequences to manage toner aggregation based on usage patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the developer carrier continues rotating in the first direction during long printing operations, then productivity is maintained, but toner aggregation occurs at the developer lifting section causing abnormal images
Solution Approach 1:
The developer carrier rotation is made periodic by alternating between first direction rotation (for normal image formation) and second direction rotation (for toner aggregation prevention). The controller executes this periodic reversal based on printed sheet count thresholds, ensuring toner is continuously agitated and prevented from aggregating while maintaining overall productivity through automated cycle management.
2Reliability
If reverse rotation is executed frequently to remove aggregated toner, then image quality is improved, but productivity decreases due to increased stopping time
Solution Approach 1:
The controller monitors the printed sheet count and uses this feedback to determine when reverse rotation should occur. By setting thresholds based on accumulated printing volume, the system executes reverse rotation only when necessary to prevent aggregation, rather than on a fixed schedule. This feedback-based approach optimizes the balance between image quality maintenance and productivity by minimizing unnecessary stopping.
3Reliability
If the developer carrier stops rotation frequently, then toner aggregation is prevented, but loss of time increases due to repeated start-stop cycles
Solution Approach 1:
The system performs preliminary action by continuously rotating the developer carrier in the first direction during normal operation, which maintains toner distribution. The reverse rotation is then executed as a preliminary preventive measure before aggregation becomes severe, based on predicted usage patterns from sheet count monitoring. This allows the system to maintain reliability without excessive stopping by anticipating when intervention is needed.
Data Source
AI summary
An image forming apparatus includes a controller that starts a forced drive stop sequence for stopping image formation at least by stopping rotation of a developer carrier in a first direction when a number of printed sheets reach a threshold. The forced drive stop sequence rotates the developer carrier in a second direction for a prescribed time period when the image formation is stopped. The forced drive stop sequence stops the rotation of the developer carrier in the second direction and resumes the image formation after the prescribed time has elapsed.