Document Conveying Device With Downstream-Angled Sensor
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Solution Overview
Problem
Existing document conveying devices face challenges in accurately detecting documents due to the risk of false detection by reflective optical sensors when light is reflected by the pickup roller, and there is a need to increase the capacity of the sheet feeding and discharge trays without increasing their size.
Innovation Solution
The document conveying device incorporates a sheet feeding tray with a lifting wall part and a reflective optical sensor that emits light in a direction inclined downstream from the vertical, along with a fixed wall part and a lifting wall part that are integrated with the sheet feeding tray, allowing for increased capacity and accurate document detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reflective optical sensor is disposed to emit light vertically upward to detect the document, then the detection position can be as close as possible to the lifting wall part, but false detection occurs due to light reflection by the pickup roller
Solution Approach 1:
The optical sensor is configured to emit light at an asymmetric angle (inclined downstream direction) rather than vertically upward, creating an asymmetric optical path that avoids reflection from the pickup roller while maintaining detection capability near the lifting wall part
2Quantity of substance
If the capacity of the sheet feeding tray and discharge tray is increased, then more documents can be stored, but the physical size of the trays must be enlarged
Solution Approach 1:
The lifting wall part is made movable rather than fixed, allowing it to change position vertically. This dynamic structure enables the tray to accommodate varying document quantities by adjusting the effective storage height, increasing capacity without requiring a larger physical footprint
Solution Approach 2:
The lifting wall part moves in the vertical dimension to accommodate documents, rather than expanding the tray horizontally. By utilizing vertical space dynamically through the movable lifting wall, the tray achieves increased document capacity while maintaining compact horizontal dimensions
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 enhances document detection accuracy by minimizing false detection and increases the capacity of the sheet feeding and discharge trays without enlarging their physical dimensions.
Implementation Method 1
The reflective optical sensor emits light in a direction inclined downstream of the sheet feeding direction from a vertically upward direction
Data Source
AI summary
A document conveying device includes a sheet feeding tray, a sheet feeding mechanism, a sheet feeding tray lifting mechanism, a top plate, a fixed wall part, a lifting wall part, and a reflective optical sensor. The top plate is in contact with a lower surface of the document to be fed. The fixed wall part is provided extending downward from an upstream side end portion of the top plate, and is fixed in position. The lifting wall part is provided extending upward from a downstream side end portion of the sheet feeding tray, and lifted and lowered along the fixed wall part together with the sheet feeding tray. The reflective optical sensor detects the document placed on the sheet feeding tray. The reflective optical sensor emits light in a direction inclined downstream of the sheet feeding direction from a vertically upward direction.