Developing Device Filter Section Toner Scattering Prevention
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Solution Overview
Problem
Conventional image forming apparatuses face issues with toner scattering and leakage around the developing roller, which affects the quality of the toner image formed on the photoconductive drum, due to the accumulation of toner and air pressure changes within the developing device.
Innovation Solution
The developing device incorporates a stationary magnet with magnetic poles and a rotatable sleeve carrying toner and magnetic carrier, along with a conveying screw and filter sections to manage toner distribution and air flow, preventing toner scattering by utilizing magnetic fields for separation and air discharge through strategically positioned openings in the standing wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a side seal is formed with an opening to allow toner accumulation around the seal, then toner scattering around the developing roller is prevented, but air pressure changes within the developing device cause toner leakage through the opening
Solution Approach 1:
A filter member is introduced as an intermediary component between the opening and the external environment. The filter member allows air to pass through while blocking toner particles, thereby mediating between the need for air pressure equalization and the need to prevent toner leakage. This resolves the contradiction by allowing both functions to coexist without direct conflict.
Solution Approach 2:
The filter member is selectively positioned at the opening location where air pressure equalization is needed. The filter has different properties for air permeability and toner impermeability, applying local quality differentiation to resolve the contradiction between allowing air flow and preventing toner escape at this specific location.
2Productivity
If the conveying screw is positioned to face the developing roller, then developer is effectively supplied to the developing roller, but toner accumulates around the side seal and scatters
Solution Approach 1:
The filter member acts as an intermediary that allows the conveying screw to face the developing roller for effective developer supply while preventing the harmful effect of toner accumulation and scattering. The filter blocks toner from escaping through the opening while allowing air flow to maintain proper pressure balance.
3Object-affected harmful factors
If the developing device is sealed to prevent toner leakage, then toner scattering is prevented, but air pressure changes cause toner to accumulate and leak around the side seal
Solution Approach 1:
The filter member is made of porous material that allows air molecules to pass through while blocking larger toner particles. This porous structure enables the device to maintain a semi-sealed state where toner is contained but air pressure can equalize, preventing both toner scattering and toner accumulation caused by pressure changes.
Solution Approach 2:
The filter member serves as an intermediary between the sealed interior and the external environment, allowing selective passage of air while blocking toner. This resolves the contradiction by enabling controlled interaction between the sealed system and external atmosphere.
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 effectively prevents toner scattering and leakage by ensuring controlled toner supply and air flow, maintaining image quality and apparatus efficiency.
Implementation Method 1
The stationary magnet includes a separation pole for producing a magnetic field that causes separation of developer from the sleeve
Implementation Method 2
The housing includes a standing wall disposed downstream of the developing position in a rotational direction of the sleeve and facing the developing roller. The standing wall is formed with at least one opening that faces the separation pole in a horizontal direction. The developing device further includes at least one filter section disposed on one side surface of the standing wall that is opposite to the other side surface facing the developing roller, the at least one filter section covering the at least one opening
Data Source
AI summary
A developing device includes a housing, a developing roller, a developer conveying section, and a conveying screw. The developing roller includes a stationary magnet, and a sleeve rotatable around the stationary magnet. The developing roller faces a photoconductive drum. The developer conveying section is disposed below the developing roller for circularly conveying developer therein. The conveying screw conveys developer to supply developer to the developing roller. The stationary magnet includes a separation pole for producing a magnetic field that causes separation of developer from the sleeve. The housing includes a standing wall disposed downstream of the developing position in a rotational direction of the sleeve and facing the developing roller. The standing wall is formed with at least one opening that faces the separation pole in a horizontal direction. The developing device further includes at least one filter section covering the at least one opening.