Magnetic Pole Segmentation for Toner Density Control
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Solution Overview
Problem
Existing developing devices for image forming apparatuses face challenges in efficiently transferring and peeling off toner from a rotating member to an image carrier while maintaining appropriate toner density, leading to scattered toner and reduced image quality.
Innovation Solution
A developing device with a magnetism generating member featuring magnetic poles arranged in a circumferential direction, including a developer pumping pole, peeling-off pole, and a magnetic body positioned between the peeling-off and pumping poles, which helps in transporting and separating the developer, ensuring appropriate toner distribution and density on the image carrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional developing device transfers toner from a rotating member to an image carrier, then toner is supplied to the image carrier, but toner scatters and toner density becomes inappropriate
Solution Approach 1:
The magnetism generating member is divided into multiple magnetic poles (first magnetic pole, second magnetic pole, third magnetic pole) with different polarities arranged in the circumferential direction. This segmentation creates distinct magnetic fields for different functions: the first magnetic pole attracts and transports developer, the second magnetic pole peels off toner from the rotating member, and the third magnetic pole prevents toner scattering. By dividing the magnetic field generation into separate functional zones, the device achieves precise control over toner density and prevents scattering that would occur with a single undifferentiated magnetic field.
Solution Approach 2:
Different regions of the magnetism generating member are assigned different magnetic pole configurations tailored to local functional requirements. The first magnetic pole region is optimized for developer attraction and transport, the second magnetic pole region for toner peeling, and the third magnetic pole region for preventing toner scattering. This local differentiation ensures that each zone performs its specific function optimally, resulting in appropriate toner density control and prevention of harmful toner scattering.
2Manufacturing precision
If the magnetism generating member has multiple magnetic poles, then toner distribution is improved, but device complexity increases
Solution Approach 1:
Multiple magnetic poles with different functions (developer attraction, toner peeling, and scattering prevention) are merged into a single magnetism generating member structure. Rather than using separate components for each function, the patent integrates all magnetic pole functions into one unified member, reducing overall device complexity while achieving improved toner distribution uniformity through the coordinated action of the different magnetic poles.
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 effectively transfers toner to the image carrier, maintains appropriate toner density, and prevents toner scattering, resulting in improved image quality and efficient operation of the image forming apparatus.
Implementation Method 1
a magnetism generating member having plural magnetic poles polarized in a circumferential direction thereof
Implementation Method 2
a developer pumping pole that is provided in the magnetism generating member, and that pumps up the developer, which is supplied from a developer accommodating portion accommodating the developer, to the surface of the rotating member
Implementation Method 3
a developer peeling-off pole that is provided in the magnetism generating member below a rotation axis of the rotating member in a vertical direction on an upstream side of the developer pumping pole in a rotational direction of the rotating member, and that peels off the developer from the surface of the rotating member
Data Source
AI summary
A developing device includes: a developing member including a magnetism-generating member having plural magnetic poles polarized in a circumferential-direction thereof, and a rotating member that is rotated about the magnetism-generating member; a developer-pumping pole provided in the magnetism-generating member, and that pumps up the developer, which is supplied from a developer accommodating portion, to the rotating member surface; a developer-peeling-off pole provided in the magnetism-generating member below a rotation axis of the rotating member in a vertical direction on an upstream side of the developer-pumping pole in a rotational-direction of the rotating member, that peels off the developer from the rotating member surface; and a magnetic body provided in at least a portion between a facing position facing the developer-peeling-off pole in a circumferential-direction of the rotating member and an intermediate position between the developer-peeling-off pole and the developer-pumping pole in the circumferential direction, facing the rotating member surface.