Roll Sheet Feeding Detection and Jam Prevention
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Solution Overview
Problem
Existing printing apparatuses face conveyance errors and sheet jams even when the sheet leading end is detected, as they lack a mechanism to ensure proper feeding into the normal path.
Innovation Solution
A printing apparatus with a holding unit, printing unit, driving unit, sensor, detecting unit, and determining unit that rotates the roll in reverse to detect the sheet leading end and then switches direction to supply the sheet, using a sensor to monitor the feeding state and adjust the conveyance path to prevent jams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the roll is rotated in reverse direction to detect the sheet leading end, then the detection accuracy is improved, but the feeding reliability deteriorates because the leading end may not go to the normal feeding path
Solution Approach 1:
The patent applies preliminary action by rotating the roll in reverse direction before normal feeding to detect the sheet leading end position. This preliminary detection phase allows the system to identify the exact location of the leading end, and then a subsequent normal rotation phase guides it to the correct feeding path, ensuring both detection accuracy and feeding reliability
Solution Approach 2:
The patent uses dynamics by changing the rotation direction of the roll based on the detection phase. The driving unit switches between reverse rotation (for detection) and normal rotation (for feeding), dynamically adapting the rotation direction to achieve both accurate detection and reliable feeding without mechanical structural changes
2Difficulty of detecting and measuring
If the roll is rotated in reverse direction for detection, then the detection capability is improved, but conveyance errors such as jams occur more frequently
Solution Approach 1:
The reverse rotation serves as a preliminary action to detect the leading end position before actual feeding occurs. During this detection phase, the system identifies the leading end without attempting to convey it through the full path, thereby avoiding jams. After detection, normal rotation is used for conveyance, separating the detection and conveyance functions to eliminate conveyance errors
Solution Approach 2:
The patent implements feedback by using the sensor to detect the sheet leading end position during reverse rotation, then using this detection information to control the driving unit's rotation direction switch. The feedback loop ensures that the system responds appropriately to the detected position, guiding the leading end to the correct feeding path and preventing conveyance errors
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 solution enables more reliable automatic sheet feeding by detecting the sheet leading end and adjusting the conveyance path, reducing the likelihood of jams and ensuring smooth sheet supply to the printing unit.
Implementation Method 1
a sensor configured to change its output value in accordance with a distance to the sheet of the roll sheet held in the holding unit
Data Source
AI summary
Automatic sheet feeding of an installed roll is performed more reliably. To this end, a leading end of a sheet is detected on the basis of a change in an output value of a sensor while causing a roll to rotate in a winding direction using a sensor capable of detecting a distance to the sheet separated from the roll. After the detection, the roll is caused to rotate in a feeding direction, and a feeding state of the sheet is determined on the basis of a change in the output value of the sensor.