Developer Level Sensing With a Vertically Moving Magnetic Body
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Solution Overview
Problem
Existing image forming apparatuses with a movable magnetic body inside the developer accommodation portion reduce the available space for developer, necessitating a redesign to enhance developer capacity and detection accuracy.
Innovation Solution
An image forming apparatus with a magnetic body unit supported to be movable relative to the accommodation portion, utilizing a rotary mechanism that includes a contact period during which the magnetic body unit aligns with a magnetic sensor to detect the developer level, allowing for efficient developer detection without reducing accommodation space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a moving member is added to move the magnetic body relative to the developer, then developer level detection accuracy is improved, but the available accommodation space for developer is reduced
Solution Approach 1:
Instead of moving the magnetic body horizontally across the developer surface, the patent inverts the approach by making the magnetic body move vertically into and out of the developer. This vertical reciprocating motion allows the magnetic body to contact the developer only during the downward stroke, eliminating the need for a horizontal moving member that would occupy accommodation space.
Solution Approach 2:
The patent extracts the horizontal moving member from the system by implementing a vertical reciprocating mechanism. The magnetic body is suspended on a vertical guide and moved only in the vertical direction, removing the horizontal translation mechanism that would otherwise occupy space within the accommodation portion.
2Reliability
If the magnetic body is continuously moved relative to the developer, then detection responsiveness is improved, but the complexity of the moving mechanism increases
Solution Approach 1:
The patent implements periodic reciprocating motion of the magnetic body, where the magnetic body moves downward to contact the developer for detection, then returns upward to a non-contact position. This periodic action ensures timely detection while simplifying the mechanism compared to continuous horizontal movement, as the magnetic body remains stationary horizontally and only executes vertical reciprocation.
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
Enhances developer detection accuracy while maintaining the developer capacity by optimizing the use of space and improving the reliability of developer level sensing.
Implementation Method 1
a magnetic sensor, wherein a rotation period for the rotary to make one rotation includes a first period, wherein in the first period, the moving direction includes a vertically downward component
Implementation Method 2
the first period includes a contact period during which the magnetic body unit contacts the developer and is received by the developer
Data Source
AI summary
The present invention is directed to reducing moving members for moving a magnetic body relative to a developer. An image forming apparatus includes a developing unit including an accommodation portion, a developing member, and a magnetic body unit, the magnetic body unit being located inside the accommodation portion and supported to be movable relative to the accommodation portion in a moving direction, a rotary, and a magnetic sensor. A rotation period for the rotary to make one rotation includes a first period. In the first period, the moving direction includes a vertically downward direction. The first period includes a contact period during which the magnetic body unit is received by a developer. The contact period includes timing at which a rotation center of the rotary, the magnetic body unit, and the magnetic sensor are aligned on a straight line in a radial direction of rotation of the rotary.