Registration Roller Displacement for Sheet Alignment
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Solution Overview
Problem
Image forming apparatuses experience sub scanning obliqueness due to misalignment and differences in roller diameters, leading to poor image quality with existing registration displacement control methods that rely on line sensors for displacement calculations, resulting in positional deviations and distortions, especially with long sheets.
Innovation Solution
The implementation of a control system that uses pre-specified displacement values and directions for registration rollers, allowing for both rightward and leftward displacements based on preset values to correct sheet position deviations, with the displacement stopped when the sheet edge aligns with the target position, reducing errors and improving image alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If registration rollers are displaced based on line sensor sensing results, then sheet position deviation can be corrected, but the side end of the sheet deviates from the reference position when displacement is stopped
Solution Approach 1:
The control unit specifies a displacement end position in advance before actually displacing the registration roller. This predetermined position is calculated based on the detected sheet side end position and the conveyance distance to the target position (transfer section or fixing section). By planning the displacement endpoint beforehand, the system ensures that the sheet will be properly positioned at the target location, preventing edge deviation when displacement stops.
Solution Approach 2:
The system continuously detects the sheet side end position using a line sensor during the conveyance process. This real-time feedback information is used by the control unit to dynamically adjust and specify the appropriate displacement end position for the registration roller, ensuring accurate sheet positioning at the target section while preventing edge deviation.
2Stability of the object's composition
If registration rollers are displaced to correct sheet position, then sub scanning obliqueness is reduced, but image positional deviation occurs due to misalignment through transfer section
Solution Approach 1:
The control unit calculates and specifies the displacement end position of the registration roller in advance, considering the conveyance distance to both the transfer section and fixing section. This predetermined positioning ensures that the sheet is correctly aligned at both critical sections, preventing image positional deviation while correcting sub scanning obliqueness.
Solution Approach 2:
The line sensor continuously provides feedback on the sheet side end position during conveyance. The control unit uses this information to dynamically adjust the registration roller displacement, ensuring that the sheet maintains proper alignment through both the transfer section and fixing section, thereby preventing image positional deviation.
Data Source
AI summary
An image forming apparatus includes a transfer section that transfers an image onto a sheet, a sheet conveying member that is provided upstream of the transfer section in a sheet conveyance direction and conveys the sheet, and a hardware processor that controls displacement of the sheet conveying member in such a way that the sheet is displaced along the width direction of the sheet. The hardware processor performs first displacement control in which the sheet conveying member is displaced in a direction which is specified in advance with respect to the sheet and in which an edge of the sheet in the width direction is directed toward a target position and second displacement control in which the sheet conveying member is displaced in the direction opposite the direction of the first displacement.