Sheet Convey Device Width Recognition via Sensor Positioning
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Solution Overview
Problem
Conventional image reading devices misrecognize the width of sheets due to oblique placement, leading to incorrect sheet sizes being supplied to printers, resulting in undesired image recording.
Innovation Solution
A sheet-convey device with a sheet holder and sensors positioned to detect sheet edges accurately, including a first sensor inside the width of a standard sheet and a second sensor outside the width but upstream, ensuring correct sheet width recognition even when sheets are obliquely placed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are arranged in a row perpendicular to the conveyance direction to detect sheet width, then sheet width recognition is enabled, but misrecognition occurs when sheets are obliquely placed
Solution Approach 1:
The patent transitions from detecting sheet width in only one dimension (perpendicular to conveyance) to detecting in multiple dimensions by adding sensors in the conveyance direction. The first sensor detects the leading end edge and the second sensor detects the trailing end edge, allowing the system to calculate sheet width based on the distance between sensors regardless of oblique placement angle.
Solution Approach 2:
The patent divides the sheet detection function into separate sensing points: a first sensor positioned at the leading end edge detection position and a second sensor positioned at the trailing end edge detection position. This segmentation allows independent detection of different sheet boundaries, enabling accurate width measurement even when the sheet is not perfectly aligned.
2Manufacturing precision
If side guides are positioned close together to match standard sheet width, then sheet positioning is precise, but users cannot smoothly place larger sheets
Solution Approach 1:
The patent makes the side guide positions adjustable rather than fixed. The side guides can be moved to different positions along the conveyance direction to accommodate sheets of varying widths. This dynamic adjustment allows the system to maintain precise positioning for standard sheets while enabling easy placement of larger sheets by simply moving the side guides outward.
Solution Approach 2:
The side guides are designed to serve multiple functions: they provide precise positioning for standard sheet sizes when positioned close together, and they can be adjusted to accommodate larger sheet sizes. This multi-functionality allows a single device to handle various sheet widths without requiring separate positioning mechanisms for different sheet types.
Data Source
AI summary
A sheet-convey device, includes a holder, a convey member, and a recognizer. On the holder, a first sheet having a first width and a second sheet having a second width larger than the first width are placeable. The convey member conveys a sheet placed on the holder in a predetermined direction. The recognizer recognizes a width of the sheet and includes first and second sensors for sensing whether a part of the sheet is present at respective first and second positions of the holder. The first position is located inside of the first width in the widthwise direction with the first sheet placed on the holder, while the second position is located outside of the first width and inside of the second width with the second sheet placed on the holder. The second position is located upstream of the first position in the predetermined direction.