Roll Sheet Peeling Detection via Reverse Rotation Control
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Solution Overview
Problem
Existing printing apparatuses struggle to accurately detect sheet peeling from a roll due to varying peeling rates influenced by sheet stiffness and electrostatic charging, leading to potential inaccuracies in subsequent sheet feeding operations.
Innovation Solution
A printing apparatus equipped with a holding unit, a printing unit, a driving unit, a sensor that changes output based on the distance to the sheet, and a control unit that rotates the roll in opposite directions to detect and manage sheet peeling accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the sheet leading end is detected using a momentary signal pulse during peeling, then the detection method is simple, but the detection accuracy deteriorates because signal timing varies with peeling rate
Solution Approach 1:
The roll is rotated in the opposite direction before normal operation to deliberately separate the sheet leading end from the roll. This preliminary action ensures the sheet is properly positioned and peeled before detection begins, creating consistent initial conditions that improve subsequent detection accuracy regardless of varying peeling rates during normal operation
Solution Approach 2:
The optical sensor continuously monitors the sheet position and provides feedback signals to the control unit. The control unit adjusts the roll rotation based on this feedback, maintaining accurate detection of the sheet leading end by compensating for variations in peeling rate through real-time control adjustments
2Productivity
If the roll is rotated in the winding direction to supply sheet, then continuous printing operation is maintained, but sheet peeling detection becomes inaccurate due to varying peeling rates
Solution Approach 1:
The roll rotation is periodically reversed to rotate in the opposite direction at intervals. This periodic reverse rotation resets the sheet peeling condition and allows the optical sensor to accurately detect the sheet leading end position, ensuring detection accuracy is maintained while allowing continuous printing operations to proceed
Solution Approach 2:
Instead of rotating the roll only in the winding direction, the system inverts the rotation direction periodically to rotate in the opposite direction. This inversion allows the sheet to be deliberately separated and repositioned, providing accurate detection opportunities while maintaining overall continuous operation capability
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 apparatus achieves precise detection of sheet peeling and enables automatic feeding, ensuring high accuracy and reliability in sheet handling processes.
Implementation Method 1
the optical sensor disclosed in Japanese Patent Laid-Open No. 2011-37557 detects the peeling of the sheet on the basis of an on-output obtained by reflected light at a moment at which the leading end of the sheet peeled from the roll passes through a sensor optical axis
Data Source
AI summary
A roll sheet with a continuous sheet wound in a roll form is rotated in a forward direction to supply the sheet to a printing unit. A sensor whose output is changed in accordance with a distance between the sensor and the sheet is used. A rotation direction of the roll sheet is switched from an opposite direction to the forward direction on the basis of the output of the sensor during rotation of the roll sheet in the opposite direction.