Sheet Conveying Device Attitude Correction via Reflectance-Adaptive CIS Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sheet conveying devices in image forming apparatuses struggle to correct the attitude of sheets with high accuracy, particularly when conveying sheets with different reflectance values, such as colored sheets, due to limitations in detection and correction mechanisms.
Innovation Solution
The implementation of a sheet conveying device with multiple CISs (Contact Image Sensors) positioned along the sheet conveyance path, including upstream and downstream detectors, and a controller that adjusts light emission times, intensities, and conveying speed based on detected reflectance to perform primary and secondary corrections, ensuring accurate angular and lateral displacement adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple CISs are disposed at intervals to detect sheet attitude for primary and secondary corrections, then sheet positioning accuracy is improved, but device complexity increases
Solution Approach 1:
The sheet detection and correction process is segmented into multiple stages: first detection by upstream CIS, primary correction by sheet holding rollers, second detection by downstream CIS, and secondary correction by sheet holding rollers. This segmentation allows each detector and correction mechanism to focus on specific measurement and adjustment tasks, improving overall positioning accuracy while maintaining manageable system complexity through functional division.
Solution Approach 2:
The system implements feedback control by using detection results from upstream and downstream CISs to guide correction operations of the sheet holding rollers. The detection-corsrection-detection-corsrection cycle creates a closed-loop feedback system that continuously refines sheet positioning accuracy, with each feedback cycle building upon previous corrections to achieve high precision.
2Manufacturing precision
If recorrecting operations are performed based on detection results from upstream and downstream CISs, then correction accuracy is improved, but time consumption increases
Solution Approach 1:
The upstream CIS performs preliminary detection of sheet attitude before the sheet reaches the correction zone. This preliminary detection allows the system to prepare correction commands in advance, so that when the sheet arrives at the sheet holding rollers, the correction can be applied immediately without waiting for detection completion, thus reducing overall correction time while maintaining accuracy.
Solution Approach 2:
The correction process is organized into periodic cycles: detection by upstream CIS, primary correction by rollers, detection by downstream CIS, and secondary correction by rollers. This periodic structure allows the system to efficiently manage multiple correction operations without continuous interference, optimizing the balance between correction accuracy and time consumption through rhythmic, predictable operation patterns.
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 configuration enables precise correction of sheet attitude regardless of reflectance, enhancing the accuracy of sheet positioning and reducing errors in image formation processes.
Implementation Method 1
various sheets having different reflectance due to different colors are conveyed
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A sheet conveying device (30), included in an image forming apparatus (1), includes a pair of rollers (31) to convey a sheet (P), a detector (35,36,37) to optically detect an attitude of the sheet (P), one of a rotation device (62) to rotate the pair of rollers (31) in a direction parallel to a plane of the sheet (P) and a moving device (63) to move the pair of rollers (31) in a width direction, and a controller (90) to correct the attitude of the pair of rollers (31), based on a detection result of the detector (35,36,37), by setting, according to reflectance of the sheet (P), at least one of a light emission time of the detector (35,36,37), a time interval of the correcting operation, light emission intensity of the detector (35,36,37) and a conveying speed of the sheet (P).