Sheet Surface Detection Mechanism for Compact Image Forming Apparatus
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Solution Overview
Problem
Conventional sheet feeding devices in image forming apparatuses face issues with upsizing due to the need for a large suction duct to accommodate sheet surface detecting sensors, leading to increased energy consumption and difficulty in maintaining air-tightness, which results in feeding failures like double feeding and jamming, especially when sheets are curled.
Innovation Solution
A sheet surface detecting mechanism is positioned outside the suction duct with a sensor flag and sensors that pivot to detect the sheet surface, allowing for precise detection without increasing the suction duct size, and a sheet surface detecting member extends under the conveying belt to ensure accurate sheet separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sheet surface detecting sensors are disposed inside the suction duct, then sheet surface detection is enabled, but the suction duct size increases leading to apparatus upsizing
Solution Approach 1:
The sheet surface detecting mechanism is extracted from the suction duct and repositioned to the exterior. The sensor flag and sensors are now located outside the suction duct, eliminating the need for internal mounting space while maintaining detection functionality through the duct wall or opening.
Solution Approach 2:
The suction duct wall or opening serves as an intermediary medium that allows the sheet surface detecting sensors to detect sheet position from the exterior without being physically inside the duct. This intermediary structure enables detection while preserving the compact duct design.
2Measurement precision
If suction duct size is increased to accommodate sensors, then sheet surface detection is possible, but energy consumption increases
Solution Approach 1:
The detecting mechanism is extracted from the suction duct interior, eliminating the need for increased duct volume. This maintains the original compact suction duct design and associated energy-efficient airflow characteristics while still enabling sheet surface detection from the exterior.
3Measurement precision
If suction duct size is increased, then sensors can be accommodated, but air-tightness maintenance becomes difficult leading to feeding failures
Solution Approach 1:
The sheet surface detecting mechanism is completely extracted from the suction duct interior and relocated to the exterior. This eliminates all penetrations, openings, or mounting structures within the duct that would compromise air-tightness, thereby maintaining reliable sealing while enabling detection functionality.
4Volume of stationary object
If sensors are disposed outside the suction duct, then apparatus size is reduced, but sheet surface detection accuracy may be compromised
Solution Approach 1:
The suction duct wall or designated opening acts as an intermediary that transmits sheet surface information from the interior to the exterior sensors. This intermediary structure allows accurate detection of sheet surface position and curvature without requiring the sensors to be physically inside the duct, thereby maintaining both compact size and detection accuracy.
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 enables reliable sheet feeding without upsizing the apparatus, preventing double feeding and jamming by ensuring accurate detection and separation of sheets, even when sheets are curled, while maintaining air-tightness and reducing energy consumption.
Implementation Method 1
a separation fan 31, and a separation duct 32 supplying air from the separation fan 31 to each of the nozzles 33 and 34
Implementation Method 2
a suction fan 36 generating a negative pressure for causing a sheet S to be sucked to the sucking and conveying belt 21
Data Source
AI summary
A sheet surface detecting mechanism, which detects the upper surface of sheets stacked on a tray, including: a sensor disposed in a position spaced apart from a conveying portion; a pivotal sensor flag turning the sensor ON/OFF; and a sheet surface detecting member being disposed in parallel with the sheets stacked on the tray, moving in a vertical direction while causing the sensor flag to pivot in contact with the upper surface of the sheets, and turning the sensor ON/OFF via the sensor flag.