Developing Device Magnetic Roller Guide Columnar Body
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Solution Overview
Problem
In developing devices with magnetic rollers, the developer upstream of a transport path can be retained due to magnetic force, leading to unstable developer transport as batches of retained developer flow repetitively.
Innovation Solution
A developing device with a first conveyance roller having a larger radius than the transport screw's shaft, a scraping wall to direct the developer away from the magnetic roller, and a guide columnar body that prevents the developer from being attracted by the magnetic force, ensuring stable transport by guiding the developer to the upstream end of the transport path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a magnetic roller is used to convey developer from one transport path to another, then developer conveyance is improved, but developer retention upstream of the transport path occurs causing unstable transport
Solution Approach 1:
A non-magnetic guide columnar body is introduced as an intermediary element between the magnetic roller and the upstream transport path. This guide body has a peripheral surface that receives developer from the magnetic roller and guides it to the upstream end portion, while its length ensures that developer at the upstream end is not attracted by the magnetic force. This intermediary structure prevents direct magnetic attraction of upstream developer while maintaining the conveyance function.
Solution Approach 2:
The guide columnar body extends in the axial direction perpendicular to the rotation plane of the magnetic roller, creating a three-dimensional path for developer flow. By positioning the guide body such that its length in the axial direction prevents magnetic attraction of upstream developer, the solution adds a spatial dimension to control developer movement and eliminate retention issues.
2Force
If the magnetic roller has a larger radius than the screw shaft, then developer attraction capability is improved, but magnetic force extends further causing upstream developer retention
Solution Approach 1:
The guide columnar body acts as a physical barrier and intermediary that blocks the extension of magnetic force lines to the upstream transport path. By positioning this non-magnetic structure between the magnetic roller and upstream developer, the harmful magnetic attraction is prevented while the useful attraction of downstream developer is maintained.
Solution Approach 2:
The magnetic roller is designed with localized magnetic properties - it attracts developer at the downstream end where needed, but the guide columnar body creates a local non-magnetic zone that prevents attraction at the upstream end. This local differentiation of magnetic influence zones allows the system to achieve selective attraction without unintended side effects.
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 prevents developer retention upstream of the transport path, ensuring consistent and stable developer transport by using a magnetic roller with a larger radius and a guide columnar body to direct the developer away from the magnetic force, thus maintaining stable flow rates.
Implementation Method 1
a first conveyance roller that has a larger radius than a radius of a shaft of the first transport screw, that attracts by magnetic force the developer at a downstream end portion of a second developer transport path arranged next to the first developer transport path
Data Source
AI summary
A developing device includes a first developer transport path, called as first path hereinafter; a first transport screw that transports a developer in the first path; a first conveyance roller that is thicker than a shaft of the first transport screw, attracts by magnetic force the developer at a downstream end portion of a second developer transport path arranged next to the first path, and conveys the developer to an upper portion located upstream of the first path; a first scraping wall that scrapes and sends the attracted developer; and a first guide columnar body that is adjacent to the first conveyance roller, has a peripheral surface continuous to the first conveyance roller, receives, using the peripheral surface, and guides the sent developer to an upstream end portion of the first path, and has a length that the guided developer is not attracted by the magnetic force.