Sequential Photoconductive Drum Control for Toner Churn Reduction
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Solution Overview
Problem
Image forming apparatuses experience excessive toner churn, leading to print quality defects such as starvation, grainy print, and poor transfer, due to the simultaneous rotation of photoconductive drums and the linkage between them and the intermediate transfer member, which results in inefficient use of toner and reduced apparatus life.
Innovation Solution
The solution involves sequencing the operation of each image forming station to start and stop at the latest and earliest opportunities, respectively, by controlling the speed of photoconductive drums individually, allowing only necessary revolutions for run-in and run-out functions, thereby reducing toner churn and extending cartridge life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If photoconductive drums rotate simultaneously to provide stable motion quality, then motion stability is improved, but toner churn increases causing print quality defects
Solution Approach 1:
The patent divides the simultaneous rotation of all photoconductive drums into sequential rotation control. Each drum is controlled independently to rotate only when needed, segmenting the rotation operation across time rather than executing all drums simultaneously. This reduces toner churn while maintaining stable motion quality through coordinated sequential operation.
Solution Approach 2:
The patent implements dynamic control of photoconductive drum rotation speeds and start/stop times. The system adjusts the rotation state of each drum based on real-time printing requirements, transitioning from static simultaneous rotation to dynamic sequential rotation. This allows the system to maintain motion stability when needed while minimizing toner churn during transitions.
2Stability of the object's composition
If photoconductive drums continue rotating until intermediate transfer member completes transfer, then motion quality and slippage reduction are improved, but toner churn increases
Solution Approach 1:
The patent performs preliminary actions by pre-charging photoconductive drums and preparing them for rotation before the actual printing cycle begins. The system anticipates the intermediate transfer member's completion and sequences drum rotation accordingly, allowing drums to stop earlier without compromising transfer quality. This eliminates unnecessary toner recycling while maintaining motion quality.
Solution Approach 2:
The patent implements feedback control by monitoring the intermediate transfer member's position and status in real-time. Based on this feedback, the system dynamically adjusts photoconductive drum rotation timing and duration. When the intermediate transfer member completes its transfer, the feedback signal allows drums to stop immediately rather than continuing rotation, reducing toner churn while maintaining transfer quality.
3Reliability
If run in and run out processes are performed for each image forming station, then component preparation and cleaning are improved, but time consumption increases
Solution Approach 1:
The patent merges the run-in and run-out processes across multiple image forming stations into a coordinated sequence. Instead of each station performing complete preparation and cleaning cycles independently, the system combines these operations so that stations prepare and clean in an overlapping, coordinated manner. This reduces total time consumption while maintaining reliable component preparation and cleaning.
Solution Approach 2:
The patent maintains continuity of useful action by overlapping preparation and cleaning operations with active printing cycles. Rather than stopping all stations for run-in/run-out, the system continues useful printing actions while performing preparation and cleaning in parallel on different stations. This eliminates idle time while ensuring components are properly prepared and cleaned.
Data Source
AI summary
An image forming apparatus includes a plurality of photoconductive drums, each photoconductive drum transferring a portion of a toner image to an intermediate transfer member. The photoconductive drums are individually rotated to a printing speed such that a downstream photoconductive drum starts rotating prior to an adjacent upstream photoconductive drum starts image transfer. Similarly, an upstream photoconductive drum starts deceleration when its following downstream station has transferred image.