Sensor Shutter and Side Wall Design for Image Forming Apparatus
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Solution Overview
Problem
Image forming apparatuses face reduced detection accuracy due to foreign particles like toner and paper dust accumulating on the sensor detection surface, which can be exacerbated by the protective member's movement, potentially carrying contaminants to the sensor.
Innovation Solution
An image forming apparatus design featuring a shutter with detection holes and a cover portion, along with a holding member that includes side walls with specific overlapping areas to minimize contamination, ensuring the sensor remains clean and functional.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the protective member is moved to expose the detection surface through detection holes, then the sensor can detect the toner image, but foreign substances accumulate on the area below the detection hole and may be carried to the detection surface
Solution Approach 1:
The protective member is divided into a shutter portion with detection holes and a holding member with side walls. The side walls create separate spatial zones: a first area below the shutter that overlaps with detection holes when closed, and a second area overlapping with the window when closed. This segmentation prevents foreign substances from the first area from being carried to the detection surface by the shutter movement.
Solution Approach 2:
The holding member with its side walls acts as an intermediary structure between the detection hole area and the detection surface. The side walls create a physical barrier and spatial separation, preventing direct contact between foreign substances accumulated below the shutter and the detection surface, thus mediating the harmful effect of foreign substance transport.
2Object-affected harmful factors
If the protective member remains in the closed position covering the detection surface, then foreign substances are prevented from adhering to the sensor, but the sensor cannot detect the toner image
Solution Approach 1:
The protective member is designed to be movable between closed and open positions. In the closed position, the cover portion protects the detection surface from foreign substances. In the open position, the shutter moves away to expose the detection surface through detection holes, enabling toner image detection. This dynamic positioning allows the system to alternate between protection and detection functions.
3Measurement precision
If the shutter is designed with detection holes to permit detection, then the sensor can detect the toner image, but foreign substances can accumulate in the area below the detection hole
Solution Approach 1:
The holding member's side walls create different local zones with different functions: the first area below the shutter serves as a collection zone that overlaps with detection holes when the shutter is closed, while the second area overlaps with the window when closed. This local differentiation allows foreign substances to accumulate in the first area without being carried to the detection surface, while still permitting detection through the detection holes.
Data Source
AI summary
An image forming apparatus includes a sensor and a shutter to cover a window for the sensor. The shutter includes a detection hole to uncover the window and a cover portion to cover it. In an opening position of the shutter, the window and the hole are opposed to each other, and in a closing position of the shutter, the window and the cover portion are opposed to each other. A holder for the sensor includes a side wall opposed to a side of the sensor remote from a sheet feeding path and extended in a widthwise direction. As viewed in a horizontal direction perpendicular to the belt, the side wall is provided with a first area overlapping the hole in the closing position and a second area overlapping the window in the closing position. The first area is below the shutter and lower than the second area.