Continuous Sheet Feeding Device with Dynamic Threshold Adjustment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses face difficulties in automatically and accurately detecting the leading end of a continuous sheet wound around a spool, leading to potential skew or jam issues during sheet feeding, especially when the sheet is unevenly inserted or when the roll is set on upper stages.
Innovation Solution
A sheet feeding device incorporating a support, rotation driver, guide, biasing member, leading end sensor, roller, and outer diameter sensor, with circuitry controlling the rotation driver to determine the timing of the leading end passing and adjusting thresholds based on roll diameter and sheet thickness for precise positioning and feeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual insertion method is used, then operation simplicity is maintained, but detection accuracy and automation level deteriorate
Solution Approach 1:
The leading end sensor automatically detects the leading end of the continuous sheet when it protrudes from the roll, eliminating the need for manual insertion and positioning by the user. The system self-activates upon detecting the sheet's presence, achieving both automation and accurate detection.
Solution Approach 2:
The patent replaces manual mechanical insertion with an automated optical or electromagnetic sensing system. The leading end sensor detects the sheet's leading end through non-contact means, substituting the mechanical manual positioning process with an automated detection mechanism.
2Measurement precision
If leading end detection is performed without considering roll diameter, then device complexity is reduced, but detection precision deteriorates
Solution Approach 1:
The detection system dynamically adjusts its behavior based on the detected roll diameter. The control unit modifies detection parameters and rotation control strategies according to the specific roll size, enabling accurate detection across varying conditions without requiring multiple fixed detection systems.
Solution Approach 2:
The patent changes detection parameters based on the roll diameter measurement. The control unit adjusts rotation speed, detection threshold, and timing parameters according to the detected roll diameter, allowing the same detection system to accurately handle rolls of different sizes through parameter adaptation rather than structural complexity.
3Productivity
If rotation speed is increased to improve throughput, then productivity increases, but sheet feeding reliability deteriorates due to skew and jam
Solution Approach 1:
The rotation driver operates in periodic cycles: rotating the roll to bring the leading end to the sensor, pausing to detect the leading end position, then rotating again to feed the sheet. This periodic rotation-detect-feed cycle ensures stable sheet feeding by allowing the system to adjust and correct positioning at each detection point, preventing skew and jam even at higher speeds.
Solution Approach 2:
The leading end sensor provides continuous feedback to the control unit about the sheet's position and the roll's rotation state. This feedback loop allows the control unit to adjust rotation speed and timing in real-time, maintaining reliable sheet feeding by detecting and correcting positioning errors before they cause skew or jam.
4Adaptability or versatility
If the guide is fixed in position, then device complexity is reduced, but adaptability to different sheet conditions deteriorates
Solution Approach 1:
The guide is designed to be movable rather than fixed, allowing it to adjust its position dynamically. The support shaft enables the guide to swing or move laterally, accommodating different sheet orientations and insertion positions. This dynamic adjustment capability provides versatility in handling various sheet conditions without requiring a complex multi-component adjustment mechanism.
Data Source
AI summary
A sheet feeding device includes a support, a rotation driver, a guide, a support shaft, a biasing member, a leading end sensor, a roller, an outer diameter sensor, and circuitry. The circuitry causes the rotation driver to rotate a spool in a winding direction to determine a timing at which a signal change rate exceeds a change rate threshold as a passing time at which a leading end of a continuous sheet passes through the leading end sensor, causes the rotation driver to rotate the spool by a rotation angle in the winding direction, from the passing time, to position the leading end of the continuous sheet at a feeding start position, and rotates the spool in a feeding direction to feed the continuous sheet from the feeding start position along a guide portion. Further, the circuitry changes the change rate threshold based on an outer diameter of a roll.