Upstream Sensor Placement for Early Jam Detection in Medium Transport
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Solution Overview
Problem
Existing medium transport systems in image reading apparatuses take time to detect jams, leading to potential damage of the medium due to the need to drive a pick roller until the sheet front end reaches a paper feed sensor, and may cause creases or rotation issues during feeding.
Innovation Solution
A medium transport apparatus with sensors disposed upstream of the nipping position between the feed roller and separation roller, capable of detecting movement in the width direction, allowing for early jam detection and prevention of damage by stopping medium feeding based on detection values from multiple sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a paper feed sensor disposed downstream of a pick roller is used to detect jam, then the jam detection can be performed, but it takes time for determining a jam and the sheet might have suffered serious damage
Solution Approach 1:
The patent applies preliminary action by placing sensors upstream of the pick roller to detect sheet movement and potential jams before the sheet reaches the downstream paper feed sensor. This early detection allows the system to identify jam conditions in advance, preventing the sheet from suffering serious damage while reducing the time required for jam determination.
2Reliability
If the pick roller is driven to move the sheet front end to the paper feed sensor for jam detection, then the jam can be detected, but the sheet may suffer creases or rotation issues during feeding
Solution Approach 1:
By positioning sensors upstream of the pick roller, the system performs preliminary detection of sheet movement and jam conditions before the sheet is subjected to the pick roller's feeding action. This eliminates the need to drive the pick roller solely for detection purposes, thereby preventing creases and rotation damage to the sheet while maintaining accurate jam detection.
Solution Approach 2:
The patent replaces the mechanical feeding action of the pick roller with an optical sensing system positioned upstream. Instead of using the mechanical pick roller to move the sheet to a detection point, the system uses optical sensors to detect sheet movement and jam conditions in advance, eliminating the harmful mechanical action that causes creases and rotation.
3Loss of time
If sensors are disposed upstream of the nipping position with a gap in width direction, then early jam detection is enabled, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the detection function into multiple sensors positioned upstream of the nipping position. These sensors are arranged to detect movement in the width direction, allowing the system to identify jam conditions early. The segmentation of detection functions across multiple sensors enables early detection while distributing the complexity across separate detection elements rather than requiring a single complex sensor system.
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
Enables prompt and accurate detection of medium movement, reducing damage and detecting jams early, thereby preventing creases and other feeding issues.
Implementation Method 1
a plurality of sensors disposed at positions facing a surface of the medium and configured to detect movement of the medium
Data Source
AI summary
A medium transport apparatus includes: a medium mounting section configured to mount a medium; a feed roller configured to feed the medium from the medium mounting section; a separation roller configured to nip and separate the medium from the feed roller; a plurality of sensors disposed at positions facing a surface of the medium and configured to detect movement of the medium; and a control unit configured to stop feeding of the medium based on detection values received from the sensors, wherein the plurality of sensors are disposed upstream of a nipping position by the feed roller and the separation roller with a gap in a width direction being a direction intersecting a medium feed direction and detect movement of the medium in the width direction.