Developing Roller Magnetic Flux Distribution for Torque Reduction
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Solution Overview
Problem
In electrophotographic image forming apparatuses, the use of two-component developers containing nonmagnetic toner and magnetic carrier increases the torque required for the rotation of the developing roller, especially when low-temperature fixing toner is used, making continuous operation difficult.
Innovation Solution
A developing device with a developing roller featuring a circumferential surface with a regulating pole of single polarity, where the magnetic flux density is maximized at one position and halved at two other positions, and a regulating portion that adjusts the developer feed upstream from the developing position to reduce stress and torque requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-component developer containing nonmagnetic toner and magnetic carrier is used, then development function is improved, but torque required for developing roller rotation increases
Solution Approach 1:
The patent applies local quality by creating a specific magnetic flux density distribution at the regulating pole, where the maximum density is positioned downstream from the intermediate position between two half-maximum density points. This localized optimization of magnetic field characteristics reduces developer stress and torque while maintaining effective development.
Solution Approach 2:
The patent changes the magnetic flux density parameter by defining a specific distribution pattern at the regulating pole, where the maximum magnetic flux density is positioned at a location shifted downstream from the intermediate position between two points of half maximum density. This parameter optimization reduces the torque required for roller rotation.
2Temperature
If low-temperature fixing toner is used, then fixing temperature is reduced, but torque required for developing roller rotation increases significantly
Solution Approach 1:
The patent applies local quality by creating a specific magnetic flux density distribution at the regulating pole, where the maximum density is positioned downstream from the intermediate position between two half-maximum density points. This localized optimization of magnetic field characteristics reduces developer stress and torque while maintaining effective development.
Solution Approach 2:
The patent changes the magnetic flux density parameter by defining a specific distribution pattern at the regulating pole, where the maximum magnetic flux density is positioned at a location shifted downstream from the intermediate position between two points of half maximum density. This parameter optimization reduces the torque required for roller rotation.
3Quantity of substance
If regulating portion scrapes off redundant developer, then developer feed amount is controlled, but stress on developer increases
Solution Approach 1:
The patent uses the magnetic field at the regulating pole as an intermediary to control developer feed. By optimizing the magnetic flux density distribution, the field acts as a mediator that regulates developer amount without causing excessive mechanical stress, allowing the regulating portion to scrape off redundant developer more efficiently.
Solution Approach 2:
The patent changes the magnetic flux density parameter by defining a specific distribution pattern at the regulating pole, where the maximum magnetic flux density is positioned at a location shifted downstream from the intermediate position between two points of half maximum density. This parameter optimization reduces the torque required for roller rotation.
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 reduces the torque required for the rotation of the developing roller while maintaining image quality, particularly when using low-temperature fixing toner, by optimizing the magnetic flux density distribution and regulating developer feed, allowing for more efficient operation.
Implementation Method 1
a magnetic flux density in a direction normal to the circumferential surface of the developing roller takes a maximum in a first position on the circumferential surface in the rotation direction and takes a value half of the maximum in a second position and a third position on the circumferential surface in the rotation direction
Data Source
AI summary
A developing device includes: a developing roller that rotates in a given rotation direction; and a regulating portion that regulates the amount of feed of developer. The developing roller includes a circumferential surface on which a regulating pole having single polarity is formed. At the regulating pole, a magnetic flux density in a direction normal to the circumferential surface of the developing roller takes a maximum in a first position on the circumferential surface in the rotation direction and takes a value half of the maximum in a second position and a third position on the circumferential surface in the rotation direction. The first position is shifted downstream from a intermediate position between the second and third positions. A tip portion of the regulating portion faces a position between the first position and the intermediate position or faces the first position.