Sensor Lever Positioning for Image Formation Accuracy
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Solution Overview
Problem
Existing image forming apparatuses face challenges in achieving high precision sheet detection due to variations in the position of the door relative to the apparatus main body, affecting detection accuracy and stability of sheet conveyance.
Innovation Solution
An image forming apparatus with a movably supported opening/closing door, a rotatably mounted sensor lever, and a positioning mechanism that ensures accurate positioning of the sensor lever, allowing for precise detection without disturbing the toner image, using a sheet detection sensor to generate signals for controlling the conveyance speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sensor lever is rotatably mounted on the opening/closing door, then the detection structure becomes simpler and easier to operate, but the detection accuracy deteriorates due to position variations when the door is closed
Solution Approach 1:
The detection system is segmented into two independent parts: the sensor lever mounted on the door and the holder mounted on the apparatus main body. This segmentation allows the sensor lever to maintain operational simplicity while the holder provides stable positioning to ensure detection accuracy despite door position variations.
Solution Approach 2:
The holder acts as an intermediary component between the sensor lever and the apparatus main body. It receives the sensor lever and provides stable positioning through positioning portions, mediating between the movable door-mounted lever and the fixed detection sensor to eliminate the negative effect of door position variations on detection accuracy.
2Device complexity
If the detection sensor is provided on the door, then the device complexity is reduced, but the reliability of detection deteriorates due to position variations relative to the apparatus main body
Solution Approach 1:
The detection sensor is extracted from the door and mounted on the apparatus main body instead. This extraction eliminates the reliability problem caused by door position variations, as the sensor now has a fixed reference frame. The sensor lever on the door continues to provide the detection function through the holder mechanism.
Solution Approach 2:
The holder serves as an intermediary that connects the door-mounted sensor lever to the main body-mounted detection sensor. It includes positioning portions that engage with positioning protrusions on the main body, ensuring reliable and consistent positioning regardless of door position variations.
3Measurement precision
If the sensor lever contacts the image surface side of the sheet, then the detection function is improved, but the toner image is disturbed causing image defects
Solution Approach 1:
The sensor lever is designed to contact only the non-image surface side of the sheet, while the image surface side remains untouched. This local differentiation in contact location allows the lever to perform its detection function (detecting sheet presence, position, and conveyance) without disturbing the delicate toner image on the opposite surface.
Data Source
AI summary
A sheet conveyance apparatus includes an apparatus main body, an opening/closing door movably supported by the apparatus main body so as to be capable of opening a conveyance path through which a sheet is conveyed, a sensor lever configured to rotate when pushed by the sheet in the conveyance path, a holder rotatably holding the sensor lever and movably supported by the opening/closing door, a positioning portion provided in the apparatus main body and configured to perform positioning of the holder by coming into contact with the holder, and a sheet detection sensor provided in the apparatus main body and configured to generate a signal corresponding to the position of the sensor lever.