Document Feed Tray Lifter Control for Roller Damage Prevention
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Solution Overview
Problem
In document transport devices, when a user attempts to remove a document mistakenly placed on the document feed tray, there is a risk of damaging the document feed roller and the document if it is pulled out while sandwiched between the roller and the tray.
Innovation Solution
The document transport device incorporates a size sensor to detect changes in document size and a lifter mechanism controlled by a controller to manage the interaction between the document feed roller and the document feed tray, ensuring that the document is safely released by lowering the tray or raising the roller when a size change is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the document feed tray is raised to bring the document into contact with the document feed roller, then the document is supplied to the transport path, but the document and document feed roller may be damaged if the user pulls out the document while sandwiched between the roller and tray
Solution Approach 1:
The controller performs preliminary detection of document size changes before the document is fully sandwiched between the roller and tray. When a size change is detected, the controller preemptively lowers the tray or raises the roller to release the document, preventing the damaging situation before it occurs.
Solution Approach 2:
The system continuously monitors document size through the size sensor and provides feedback to the controller. This feedback mechanism allows the controller to detect when a user is attempting to remove a document and adjust the tray or roller position accordingly, creating a closed-loop control system that prevents damage while maintaining efficient document supply.
2Productivity
If the document feed roller is lowered to bring the document into contact with the document feed tray, then the document is supplied to the transport path, but the document and document feed roller may be damaged if the user pulls out the document while sandwiched between the roller and tray
Solution Approach 1:
The controller performs preliminary detection of document size changes before the document is fully sandwiched between the roller and tray. When a size change is detected, the controller preemptively raises the roller or lowers the tray to release the document, preventing the damaging situation before it occurs.
Solution Approach 2:
The system continuously monitors document size through the size sensor and provides feedback to the controller. This feedback mechanism allows the controller to detect when a user is attempting to remove a document and adjust the roller or tray position accordingly, creating a closed-loop control system that prevents damage while maintaining efficient document supply.
3Reliability
If a size sensor is added to detect document size changes, then damage can be prevented by controlled release, but the device complexity increases
Solution Approach 1:
The size sensor detects document size changes and the controller automatically adjusts the tray or roller position without requiring user intervention. The system serves itself by using the sensor data to make autonomous control decisions, eliminating the need for additional user interfaces or manual monitoring mechanisms.
Solution Approach 2:
The system monitors changes in document size parameters and uses these parameter changes as triggers for control actions. By focusing on a single critical parameter (document size) and its changes, the system achieves effective damage prevention with minimal sensing and control complexity.
Data Source
AI summary
A document transport device comprises: a document feed roller that supplies a document to a transport path; a document feed tray on which the document is allowed to be placed; a size sensor that detects a size of the document on the document feed tray; a lifter that causes the document on the document feed tray to come into contact with the document feed roller by raising the document feed tray; and one or more controllers that control the lifter, based on a detection signal from the size sensor, wherein the one or more controllers control the lifter in such a way as to lower the document feed tray, in a case where the size sensor detects that a size of the document is about to be changed in a state where the document on the document feed tray is made contact with the document feed roller by the lifter.