Developing Device Ventilation Unit for Toner Scattering Control
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Solution Overview
Problem
In image forming apparatuses, the scattering of toner outside the developing device due to pressure differences between developer conveying units leads to soiled internal components and output images, particularly from the second developer conveying unit where internal pressure increases and from the first unit where internal pressure decreases, causing inefficiencies and image quality issues.
Innovation Solution
A developing device with plural developer conveying units is equipped with a ventilation unit that balances internal pressures by allowing air flow between units with positive and negative pressures, using ventilation paths and openings to prevent toner scattering, ensuring efficient developer circulation and image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple developer conveying units are provided to form circulating paths, then developer mixing efficiency is improved and device width is reduced, but toner scattering increases due to pressure differences
Solution Approach 1:
The developing device is divided into multiple sealed conveying units (first, second, and third developer conveying units), each handling specific functions of developer supply, collection, and circulation. This segmentation allows independent pressure control in each unit, enabling efficient developer circulation while containing toner scattering within isolated compartments.
Solution Approach 2:
A ventilation unit acts as an intermediary system connecting the multiple conveying units. This ventilation unit includes a blowing fan that actively manages air flow between units, balancing pressure differences and preventing toner scattering while maintaining the circulation function of each segmented unit.
2Productivity
If the second developer conveying unit operates at positive pressure to collect developer, then developer collection efficiency is improved, but toner is blown out from gaps and scatters outside
Solution Approach 1:
The ventilation unit serves as a mediator between the positive-pressure second conveying unit and the external environment. The blowing fan in the ventilation unit creates a controlled air flow that counteracts the outward blowout airflow, containing toner within the sealed unit while allowing efficient developer collection to proceed.
Solution Approach 2:
The ventilation unit converts the harmful positive pressure that causes toner scattering into a beneficial controlled environment. By introducing the blowing fan, the system uses air flow management to transform the pressure difference from a source of toner scattering into a controlled condition that maintains collection efficiency while preventing contamination.
3Ease of operation
If the first developer conveying unit operates at negative pressure to supply developer, then developer supply is maintained, but efficiency decreases and redundant toner scatters outside
Solution Approach 1:
The ventilation unit acts as an intermediary that connects the negative-pressure first conveying unit to the overall pressure-balanced system. The blowing fan compensates for the negative pressure effects, maintaining developer supply capability while preventing redundant toner scattering and improving passing efficiency between units.
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
The solution significantly reduces toner scattering, maintaining a stable internal pressure environment within the developing device, enhancing image quality and preventing device soiling, even in high-speed operations.
Implementation Method 1
the internal pressure changes... the internal pressure becomes higher than the external pressure (positive pressure)... the internal pressure becomes lower than the external pressure (negative pressure)
Implementation Method 2
a suction airflow is generated as the developer carrier rotates... a blowout airflow is generated as the developer carrier rotates
Data Source
AI summary
A disclosed developing device is for accommodating a developer including carriers and a toner, and for developing a latent image formed on an image carrier. The developing device includes plural developer conveying units configured to convey the developer accommodated in the developing device and form circulating paths; and a ventilation unit configured to perform ventilation between at least one of the developer conveying units whose internal pressure increases and at least one of the developer conveying units whose internal pressure decreases.