Duplex Image Registration via Preliminary Edge Detection
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Solution Overview
Problem
Image forming apparatuses face challenges in maintaining registration accuracy while increasing productivity, particularly in duplex printing, where the sheet position in the width direction is unknown, leading to reduced productivity and increased standby periods due to the need for edge detection before image writing can commence on the second surface.
Innovation Solution
An image forming apparatus with a detector to determine the image forming position based on the detected side edge position of the sheet in the width direction, using a controller to adjust the image forming position on the second surface based on stored data from the first surface, allowing for precise alignment and reduced shift operations, thereby minimizing the shift amount and maintaining registration accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If edge detection is performed before image writing on the second surface, then registration accuracy is maintained, but productivity decreases due to increased standby periods
Solution Approach 1:
The detector detects the side edge position of the sheet during conveyance for transferring onto the first surface, before the sheet reaches the registration roller. This preliminary detection allows the image forming position to be determined in advance, eliminating the need to wait for edge detection during second surface conveyance, thus maintaining registration accuracy while improving productivity
Solution Approach 2:
The detection result obtained during first surface conveyance is stored and reused for determining the image forming position during second surface image formation. This copying of detection data eliminates redundant detection operations and enables parallel processing, thereby improving productivity without sacrificing registration accuracy
2Manufacturing precision
If the shift operation is performed with a large shift amount, then positional deviation is corrected, but sheet twist is generated reducing conveyance accuracy
Solution Approach 1:
The side edge position is detected during first surface conveyance before the sheet reaches the registration roller. This allows the required shift amount to be calculated in advance, and the registration roller to be positioned accordingly, minimizing the actual shift operation needed and reducing sheet twist
Solution Approach 2:
The detector provides feedback on the side edge position, allowing the system to calculate the precise shift amount needed. This feedback mechanism enables minimal correction operations rather than large shifts, reducing sheet twist while maintaining positional accuracy
Data Source
AI summary
An image forming apparatus configured to form images on both sides of a sheet, includes an image forming unit, which is configured to form an image on an image bearing member, and a sheet conveying device, which is configured to move the sheet being conveyed toward a width direction, which is orthogonal to a conveyance direction. After the formed image is transferred onto a first surface of the sheet, the image forming apparatus inverts and conveys the sheet to transfer an image onto a second surface. Moreover, a side edge position of the sheet in the width direction is detected during conveyance for the transferring onto each of the first surface and the second surface, and an image writing start position for the image forming unit is determined based on a result of the detection to store a result of the determination in a memory.