Skew Correction in Medium Feeding Rollers
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Solution Overview
Problem
Existing medium feeding devices in scanners face challenges in efficiently correcting medium skew without enlarging the device, as existing solutions require wide path widths and may fail to correct skew at early stages of feeding, leading to potential paper jams and suboptimal image reading.
Innovation Solution
A medium feeding device with a pair of rollers intersecting the feeding direction, equipped with a skew detection section and control mechanism that adjusts rotation speeds to correct skew at the earliest stage of feeding, allowing for efficient skew correction without enlarging the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pair of resist rollers is provided downstream from the sending roller to correct skew, then skew correction is possible, but the apparatus size increases due to the need for wide path width
Solution Approach 1:
The patent applies preliminary action by providing the resist rollers upstream (before) the sending roller instead of downstream. This allows skew correction to occur earlier in the transport path, preventing skew from developing in the first place rather than correcting it after it occurs. The resist rollers are positioned to engage the medium before it reaches the sending roller, thereby correcting skew proactively and eliminating the need for wide path width downstream.
2Measurement precision
If the pair of resist rollers is provided downstream from the sending roller, then skew detection is possible, but skew cannot be corrected in the section between the sending roller and the resist rollers
Solution Approach 1:
The patent positions the resist rollers upstream of the sending roller to perform skew correction before the medium enters the gap between the sending roller and the resist rollers. This preliminary correction ensures that skew is addressed at the earliest possible point in the transport path, covering the entire section including the area between the sending roller and resist rollers, rather than leaving this section uncorrected as in conventional designs.
3Ease of operation
If a pair of separation rollers is provided upstream from the resist rollers to separate multiple media, then separation is possible, but the rear end side of the medium is nipped and skew correction becomes difficult
Solution Approach 1:
The patent repositions the resist rollers upstream of the separation rollers, allowing skew correction to occur before the separation rollers nip the rear end of the medium. This sequence ensures that skew correction can be performed on the full length of the medium without being constrained by the separation rollers, thereby maintaining both separation capability and effective skew correction.
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 enables reliable and efficient skew correction at the upstream side of the transport path, preventing paper jams and ensuring optimal image reading without the need for a wide transport path, thus maintaining device compactness and improving reading throughput.
Implementation Method 1
a pair of first roller 14a and second roller 14b provided in a width direction (X direction) intersecting a medium feeding direction (+Y direction}, and feeds the medium from a medium placing section 11 on which the medium is placed toward the processing section
Data Source
AI summary
An image reading apparatus includes a feeding roller that includes a first roller and a second roller provided at an interval in a width direction intersecting a medium feeding direction, and feeds a sheet from a placing section; and a skew detection section that detects skew of the sheet fed from the feeding roller. Skew is corrected by giving a difference between a rotation speed of the first roller and a rotation speed of the second roller with respect to at least one of the relevant sheet detected by the skew detection section and subsequent sheets fed following the relevant sheet based on a skew amount in the sheet.