Developing Device Stirring Screw Speed Control
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Solution Overview
Problem
Existing image forming apparatuses using the trickle development method face challenges in stabilizing the amount of developer inside the case during printing, particularly when handling thick paper, requiring complex control of the rotational speed of the supply screw to prevent developer accumulation, which complicates the development process and affects development characteristics.
Innovation Solution
A developing device with a stirring screw, discharge port, and restriction portion, where the control portion drives the stirring screw at a lower mean drive speed during non-development periods to facilitate developer discharge through the restriction portion, stabilizing the developer amount inside the case without the need for high-speed drive components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the rotational speed of the supply screw is increased to discharge developer promptly during printing on thick paper, then the developer can easily pass over the reverse conveying screw and is discharged promptly, but the development characteristics are affected and the control becomes complex
Solution Approach 1:
The patent applies preliminary action by discharging surplus developer during idle periods before printing tasks begin. The control portion detects idle periods and drives the stirring screw to rotate in the discharge direction at a first rotational speed during these periods, proactively removing excess developer before it can accumulate during subsequent printing operations. This prevents the need for complex high-speed control during actual printing.
Solution Approach 2:
The patent implements periodic action by alternating between two operational modes: during idle periods, the stirring screw rotates in the discharge direction at a first rotational speed to remove developer; during printing periods, it rotates in the circulation direction at a second rotational speed to maintain developer circulation. This periodic switching simplifies control by using time-based segmentation rather than complex real-time speed adjustments.
2Quantity of substance
If the rotational speed of the supply screw is changed during printing to prevent developer accumulation, then the developer level is stabilized, but the development process becomes complex and development characteristics are affected
Solution Approach 1:
The control portion proactively removes excess developer during idle periods by rotating the stirring screw in the discharge direction, preventing accumulation before it occurs during printing. This preliminary discharge action stabilizes the developer quantity in advance, eliminating the need for complex real-time adjustments during the development process.
Solution Approach 2:
The patent maintains continuous useful action by ensuring the stirring screw is always rotating - either in the discharge direction during idle periods to remove surplus developer or in the circulation direction during printing to maintain proper developer flow. This continuous operation prevents developer accumulation without interrupting the development process, simplifying overall control.
3Productivity
If high-speed drive components are used to discharge developer quickly, then developer accumulation is prevented, but the device complexity and cost increase
Solution Approach 1:
The patent uses periodic action by operating the stirring screw at different speeds at different times: during idle periods, it rotates at a first rotational speed in the discharge direction to remove surplus developer; during printing periods, it rotates at a second rotational speed in the circulation direction. This time-based speed variation achieves effective developer management without requiring high-speed drive components throughout operation.
Solution Approach 2:
The stirring screw serves dual functions through self-service: it both circulates developer during printing operations and discharges surplus developer during idle periods. By reversing the rotation direction based on operational state, a single component performs multiple functions, eliminating the need for separate high-speed discharge mechanisms and reducing overall device complexity.
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 configuration simplifies control over the developer discharge, prevents accumulation, and maintains development stability by discharging surplus developer during idle times, reducing the complexity of managing developer levels and development characteristics.
Implementation Method 1
The stirring screw circulates the developer inside the case while stirring the developer
Implementation Method 2
The restriction portion is disposed between the stirring screw and the discharge port and restricts the movement of the developer toward the discharge port depending on the drive speed of the stirring screw
Data Source
AI summary
A developing device includes a case, a stirring screw, a discharge port, a restriction portion, and a control portion. The case stores developer. The stirring screw circulates the developer inside the case while stirring the developer. The discharge port is an opening for discharging the developer from the case. The restriction portion is disposed between the stirring screw and the discharge port and restricts the movement of the developer toward the discharge port depending on the drive speed of the stirring screw. The control portion drives the stirring screw such that, during a discharge period other than a development process period in which a development process using the developer is performed, the mean drive speed of the stirring screw per unit time is less than the mean drive speed during the development process period to move the developer toward the discharge port through the restriction portion.