Developing Device Toner Collection via Magnetic Flux Positioning
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Solution Overview
Problem
The existing hybrid developing device experiences reduced productivity due to low collection efficiency of toner moved by the supplying roller, particularly when the frequency of operation increases during non-image formation, as the toner is not effectively collected from the gap between the supplying roller and the regulating member.
Innovation Solution
The developing device incorporates a supplying roller and a developing roller with strategically positioned magnets and a regulating member, where the supplying roller is rotated opposite to the developing roller during image formation, and the magnet flux density in the tangential direction is optimized to enhance toner collection efficiency by positioning the zero magnetic flux density downstream of the upstream end of the regulating member and upstream of the second magnetic pole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the supplying roller is rotated in opposite direction during non-image formation to collect toner, then toner collection is improved, but productivity lowers when operation frequency becomes high
Solution Approach 1:
The patent replaces the mechanical rotation-based toner collection method with a magnetic field-based method. The second magnet in the supplying roller creates a magnetic flux that actively draws toner through the gap between the supplying roller and regulating member, eliminating the need for reverse rotation and enabling high-frequency operation without sacrificing collection efficiency
Solution Approach 2:
The patent changes the magnetic field parameters by positioning the second magnet and configuring its polarity to create a specific magnetic flux density distribution. The zero magnetic flux density point is positioned downstream of the upstream end of the regulating member, creating optimal conditions for toner passage through the gap without requiring mechanical reverse rotation
2Productivity
If the frequency of operation increases during non-image formation, then productivity should improve, but toner collection efficiency decreases causing productivity to lower
Solution Approach 1:
The patent replaces inertial mechanical collection with active magnetic field-based collection. The magnetic flux generated by the second magnet maintains consistent toner attraction forces regardless of operational frequency, enabling high-speed operation while preserving collection efficiency
Solution Approach 2:
The magnetic field configuration enables continuous and consistent toner collection action at all operational frequencies. The magnetic flux continuously acts on the toner particles, ensuring reliable collection whether operating at low or high frequencies, thus maintaining productivity
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 significantly improves the collection efficiency of toner, reducing toner scattering and image defects, thereby maintaining productivity even at higher operational frequencies.
Implementation Method 1
a second magnet provided non-rotationally and fixedly inside the supplying roller and including: a second magnetic pole which is provided opposed to the first magnetic pole in a position where the supplying roller opposes the developing roller and which is different in polarity from the first magnetic pole, and a third magnetic pole which is provided on a side upstream of the second magnetic pole with respect to the rotational direction of the supplying roller during the image formation
Implementation Method 2
the position where a magnet flux density of the third magnetic pole in a tangential direction to an outer peripheral surface of the supplying roller is zero is positioned downstream of an upstream end of the regulating member and upstream of the second magnetic pole
Data Source
AI summary
A developing device includes a developing container, a developing roller, a supplying roller, a first magnet including a first magnetic pole, a second magnet including a second magnetic pole and a third magnetic pole, and a regulating member provided opposed to the third magnetic pole. During non-image formation, an operation in a mode in which the supplying roller is rotated in a direction opposite to a rotational direction of the supplying roller during image formation is executable. With respect to the rotational direction of the supplying roller during the image formation, a position where a magnet flux density of the third magnetic pole in a tangential direction to an outer peripheral surface of the supplying roller is zero is positioned downstream of an upstream end of the regulating member and upstream of the second magnetic pole.