Transportation Roller and Detection Window Positioning
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Solution Overview
Problem
Existing medium transportation devices in recording apparatuses face decreased detection accuracy due to the medium being lifted from the holding surface, especially when the leading edge does not reach the downstream transportation rollers, causing positional displacement and blurring of images, which affects the accuracy of transportation distance calculation.
Innovation Solution
A medium transportation device with a non-contact detector that determines the entering direction of the medium to intersect the holding surface, positioning the detector downstream in the transportation direction to maintain the medium's contact and using an optical detector with a detection window on the holding surface to improve positional accuracy, and a transportation control unit that calculates and adjusts the actual transportation distance with feedback control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the camera is disposed on the side of the recording surface at a position downstream with respect to the transportation rollers, then the image can be captured, but the detection accuracy decreases when the medium is lifted from the holding surface
Solution Approach 1:
The patent changes the detection dimension from capturing the recording surface (which may lift) to capturing the non-recording surface (back side) of the medium. The camera is positioned to image through the holding surface from the opposite side, detecting the medium's position via its back surface or edge, thereby eliminating the focus instability caused by lifting of the recording surface.
2Ease of operation
If the medium is held only between upstream transportation rollers, then the leading edge can be fed out, but the medium is easily lifted and displaced from the expected transportation path
Solution Approach 1:
The holding surface acts as an intermediary support between the upstream and downstream transportation rollers. It provides continuous support for the medium during transportation, preventing lifting and displacement. The detection system uses this holding surface as a reference plane to accurately measure the medium's position and transportation distance.
3Measurement precision
If a portion of the medium not supported on the holding surface serves as the detection area, then the detection can be performed, but the detection accuracy decreases due to displacement in multiple directions
Solution Approach 1:
The patent applies different functional qualities to different portions of the medium. The portion in contact with the holding surface serves as a stable reference for detection, while other portions may move freely. By localizing the detection area to the supported region, the system ensures high detection accuracy while maintaining overall system simplicity.
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 the detection accuracy of the medium's position and transportation distance by preventing lifting and maintaining contact with the holding surface, reducing errors in positional detection and ensuring precise transportation, even with curled or thick media.
Implementation Method 1
a non-contact detector that obtains positional information of the medium by detecting the medium which is held on the holding surface in a non-contact manner
Data Source
AI summary
A pair of transportation rollers is configured such that a transportation driven roller is disposed at a position which is displaced downstream with respect to a position vertically above a transportation driving roller and feeds out the paper sheet guiding in obliquely downward direction. The entering direction of the paper sheet fed out from the pair of transportation rollers is determined so as to intersect the plane of the holding surface of the support table. A translucent glass that serves as a detection window of an imaging unit disposed at a position opposite to the paper sheet with respect to the holding surface is located downstream in the transportation direction with respect to an intersection position between the entering direction of the paper sheet and the holding surface. Specifically, the translucent glass is located in the proximity of an abutment position where the paper sheet abuts against the holding surface.