Developing Device Controller Speed Ratio During Drive Stop
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Solution Overview
Problem
The existing developing devices with separate drive systems for the developing sleeve and stirring screws experience out-of-balance developer circulation during drive stops, leading to insufficient developer supply and image density non-uniformity, and previous countermeasures either result in excessive stirring screw rotation, deteriorating the developer or require delayed drive stop signals, which can cause improper coating and reduce device lifetime.
Innovation Solution
A developing device with a controller that adjusts the rotational speed ratio between the developer carrying member and the stirring member during drive stops to maintain a ratio within 0.7 to 2.0 of their steady-state ratios, ensuring balanced developer circulation and preventing improper coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the stirring screw and developing sleeve are driven separately, then the developing device can achieve high-speed and downsized full-color copying, but developer circulation becomes out of balance during drive stop, causing image density non-uniformity
Solution Approach 1:
The patent implements dynamic control of the stirring screw's rotational speed during drive stop. The controller adjusts the rotational speed to maintain a specific ratio relative to the developing sleeve's speed, transforming the static separate-drive system into a dynamically balanced system that adapts to operational transitions, thereby preventing developer circulation imbalance while preserving high-speed copying capability
Solution Approach 2:
The patent changes the operational parameters of the stirring screw by controlling its rotational speed ratio during drive stop. By dynamically adjusting this parameter to maintain a specific ratio (0.5-2.0 times the developing sleeve speed), the system resolves the contradiction between high-speed operation and stable developer circulation during transitions
2Reliability
If the drive stop signal of the stirring screw is delayed compared with the developing sleeve, then developer supply to the developing sleeve is abundant during drive stop, but the stirring screw rotates excessively, causing developer deterioration and seal degradation
Solution Approach 1:
The patent implements feedback control by continuously monitoring the rotational speeds of both the stirring screw and developing sleeve, and dynamically adjusting the stirring screw's speed to maintain the desired ratio. This closed-loop control prevents both insufficient developer supply and excessive stirring screw rotation, resolving the contradiction between supply stability and component protection
Solution Approach 2:
The patent applies preliminary anti-action by proactively controlling the stirring screw's rotational speed during the transition period. Instead of allowing excessive rotation or delayed stopping, the system preemptively adjusts the speed ratio to prevent developer deterioration and seal degradation while ensuring adequate developer supply
3Quantity of substance
If the stirring screw rotates at high speed during drive stop to maintain developer circulation, then developer supply is sufficient, but the rotational speed difference causes developer stagnation reduction and improper coating
Solution Approach 1:
The patent optimizes the rotational speed ratio parameter during drive stop, setting it within a specific range (0.5-2.0 times the developing sleeve speed). This parameter adjustment ensures sufficient developer supply while preventing excessive speed differences that would cause improper coating, achieving both adequate quantity and uniform distribution
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 solution effectively suppresses out-of-balance developer circulation, maintains robustness against improper coating, and extends the device's lifetime by ensuring consistent developer supply and reducing wear on components.
Implementation Method 1
a stirring member configured to stir the developer in the developing container to supply the developer to the developer carrying member
Implementation Method 2
a factor of the out-of-balance developer circulation during drive stop of the developing device, it is possible to cite and differ in manner of drive stop resulting from a difference in moment of inertia between the stirring screw and the developing sleeve
Data Source
AI summary
A developing device includes a developing container accommodating a developer including toner and magnetic particles, a developer carrying member rotatably provided opposed to an opening of the developing container, a stirring member configured to stir the developer in the developing container to supply the developer to the developer carrying member, a first driving device configured to drive the developer carrying member, and a second driving device configured to drive the stirring member. A controller controls drive of the first driving device and the second driving device so that in a period from output of either earlier one of a stop signal of the first driving device and a stop signal of the second driving device to rotational speeds of both of the developer carrying member and the stirring member becoming not more than ½ of rotational speeds in a steady state during image formation.