Print Medium Supply Apparatus Multi-Feeding Detection
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Solution Overview
Problem
Image forming apparatuses face issues with multi-feeding of print media, where sheets overlap and are not separated properly, leading to defective printouts due to factors like friction, static electricity, and paper characteristics, causing jams and quality issues.
Innovation Solution
A print medium supplying apparatus with a processor-controlled system that includes sensors and rollers to detect and manage the gap between sheets, using a flowchart method to adjust transport timing and alignment to prevent multi-feeding by determining the preceding amount of the leading end and applying corrective actions when detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If print media sheets are supplied quickly to the image forming portion, then productivity is improved, but multi-feeding occurs causing sheets to overlap and not separate properly
Solution Approach 1:
The system performs preliminary detection of the leading end of each sheet using a sensor before the sheet reaches the image forming portion. This advance detection allows the control device to prepare for proper separation timing, preventing multi-feeding while maintaining high supply speed. The pickup roller is positioned to pick up sheets based on this preliminary information.
Solution Approach 2:
The sensor detects the position of the leading end of each sheet and provides feedback to the control device. The control device uses this feedback information to adjust the timing and positioning of the pickup roller, ensuring proper separation between sheets. This closed-loop control prevents multi-feeding while maintaining high productivity.
2Productivity
If the gap between print media sheets is reduced to supply sheets consecutively, then productivity is improved, but the sheets cannot be properly separated due to friction and static electricity
Solution Approach 1:
The system detects the leading end of each sheet in advance using a sensor positioned before the pickup roller. This preliminary detection allows the pickup roller to be positioned precisely to pick up only the leading sheet, even when sheets are supplied with minimal gap. The control device uses this information to ensure proper separation despite reduced spacing.
Solution Approach 2:
The system replaces reliance on mechanical friction-based separation with an optical detection and electronic control system. The sensor detects sheet positions optically, and the control device electronically coordinates the pickup roller timing, eliminating the need for large physical gaps between sheets to achieve proper separation.
3Reliability
If sensors and control mechanisms are added to detect and prevent multi-feeding, then reliability is improved, but device complexity increases
Solution Approach 1:
The sensor serves multiple functions: detecting the leading end of sheets, determining sheet position, and providing timing information for the pickup roller. The control device integrates detection, processing, and actuation control in a single unit, reducing the need for separate dedicated components for each function.
Solution Approach 2:
The system uses the existing sheet transport mechanism and pickup roller structure, adding only minimal detection and control components. The control device leverages the natural motion of sheets through the apparatus, requiring no additional actuators or complex mechanisms beyond what is already present in the basic sheet feeding system.
Data Source
AI summary
An example print medium supplying apparatus includes a print medium transporting device to pick up a print medium loaded in a loading portion and transport the picked-up print medium, a print medium alignment portion to align a leading end of the transported print medium, a first sensor to sense the print medium that passes through a feed roller of the print medium transporting device, and a processor to, based on a measured value with respect to the print medium sensed by the first sensor and a multi-feeding determination reference value corresponding to a sheet of the print medium, detect multi-feeding of the print medium and process the detected multi-feeding by controlling the print medium transporting device and the print medium alignment portion.