Document Feeder Ejection Port Control With Fewer Sensors
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Solution Overview
Problem
The high cost of document feeding devices is attributed to the need for multiple sensors to control the ejection port and feeding tray positions to prevent mechanical malfunctions, which increases the overall cost of the device.
Innovation Solution
A document feeding device with a simplified sensor configuration that includes a feeding-tray sheet sensor, a feeding-tray upperlimit sensor, a collision prevention sensor, and an output-tray sheet amount sensor, along with a controller to manage the lifting devices for the feeding tray and ejection port, eliminating the need for additional sensors to detect the ejection port's upperlimit position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sensors are installed to detect ejection port position and prevent mechanical malfunctions, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The collision prevention sensor is configured to perform multiple functions: it detects both the upperlimit position of the ejection port and prevents mechanical malfunctions by detecting collisions between the ejection port and feeding tray. This multi-functional approach eliminates the need for separate sensors, reducing device complexity while maintaining reliability.
Solution Approach 2:
The patent merges the function of detecting the ejection port's upperlimit position with the collision prevention function into a single sensor system. The collision prevention sensor detects when the ejection port reaches its upperlimit position by sensing contact with the feeding tray, combining what would traditionally require multiple sensors into one integrated detection mechanism.
2Reliability
If multiple sensors are installed to detect ejection port position and prevent mechanical malfunctions, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The collision prevention sensor serves multiple purposes including detecting the ejection port's upperlimit position and preventing mechanical malfunctions, reducing the total number of sensors required and thereby lowering manufacturing costs while maintaining reliability.
Solution Approach 2:
By combining the upperlimit position detection and collision prevention functions into a single sensor system, the patent reduces component count and assembly complexity, directly reducing manufacturing costs while ensuring reliable operation.
3Productivity
If the ejection port is lifted to high positions to accommodate sheet bunches, then productivity is improved, but the risk of mechanical collision increases
Solution Approach 1:
The collision prevention sensor provides real-time feedback on the position of the ejection port relative to the feeding tray. When the sensor detects that the ejection port is approaching the feeding tray, it signals the control unit to stop or reverse the lifting motion, preventing mechanical collision while allowing the ejection port to reach high positions for accommodating sheet bunches.
Solution Approach 2:
The collision prevention sensor detects potential collisions before they occur by monitoring the position of the ejection port. The control unit uses this advance warning to take preventive action by stopping or reversing the lifting motion, thereby preventing mechanical malfunctions while maintaining high productivity.
Data Source
AI summary
In a document feeding device, an ejection port outputs a document sheet to an output tray. A first lifting device lifts and lowers a feeding tray. A second lifting device lifts and lowers the ejection port. A feeding-tray sheet sensor detects that there is a document sheet on the feeding tray. A feeding-tray upperlimit sensor detects that the feeding tray reaches a first upperlimit height position. Further, the collision prevention sensor is lifted and lowered in conjunction with the feeding tray, and detects that the ejection port reaches a second upperlimit height position. An upperlimit of a movable range of the ejection port is set to be the second upperlimit height position detected in a condition that the feeding tray without any document sheets reaches the first upperlimit height position.