Sheet Feeding Sensor Placement for Accurate Detection
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Solution Overview
Problem
Existing manual sheet feeding apparatuses in image forming devices face issues with accurately detecting sheets due to floating edges being nipped by rollers, leading to erroneous detection and increased costs from the need for multiple sensors.
Innovation Solution
A sheet feeding apparatus with a reflection type photoelectric sensor disposed on a support portion that emits a detection wave intersecting with the support surface, positioned to detect the sheet within the sheet conveyance path, and optionally using a low reflectance portion or transmissive portion to prevent erroneous detection when the tray is closed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reflection type photoelectric sensor is disposed on the support portion to detect sheets, then detection accuracy is improved, but erroneous detection occurs when the tray is closed
Solution Approach 1:
A transmissive portion is introduced as an intermediary element between the detection portion and the support portion. This transmissive portion allows the detection wave to pass through when the tray is open (enabling sheet detection) but blocks the detection wave when the tray is closed (preventing erroneous detection). The transmissive portion acts as a mediator that selectively transmits or blocks the detection signal based on the tray state.
2Reliability
If multiple sensors are used to determine presence of feedable sheet, then detection reliability is improved, but device complexity and cost increase
Solution Approach 1:
The single reflection type photoelectric sensor is designed to perform multiple functions: detecting sheets when the tray is open and preventing erroneous detection when the tray is closed (through the transmissive portion). This multi-functional design eliminates the need for separate sensors for different detection purposes, thereby reducing device complexity and cost while maintaining or improving detection reliability.
3Measurement precision
If the detection portion emits detection wave in a direction intersecting with the support surface, then sheet detection capability is improved, but the detection wave may be blocked by the conveyance guide
Solution Approach 1:
The transmissive portion is strategically positioned at a specific location on the support portion where it does not interfere with the detection wave path to the sheet. This local optimization ensures that the detection wave can intersect with the support surface at the appropriate angle to detect sheets, while the transmissive portion remains positioned to avoid blocking the detection wave when the tray is closed.
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
The solution allows for accurate detection of sheets, including those in a leaning condition, while reducing the complexity and cost of the detection system by minimizing erroneous detections and ensuring reliable sheet feeding operations.
Implementation Method 1
detect the detection wave reflected by the sheet on the support surface
Data Source
AI summary
A sheet feeding apparatus includes an apparatus body, and an opening/closing member openable/closable with respect to the apparatus body and including a support portion supporting a sheet in a condition in which the opening/closing member is opened. The sheet supported by the support portion is fed by a feed portion. The opening/closing member is provided with a detection portion configured to detect the sheet on the support portion. The detection portion is disposed at a position where a detection wave emitted from the detection portion is not detected in a condition in which the opening/closing member is closed.