Printer Edge Detection for Skew Correction
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Solution Overview
Problem
Printers face issues with image position deviation due to sheet skew during conveyance, particularly in printers using continuous sheets, where existing systems struggle to accurately adjust the print start position based on the edge position of the sheet.
Innovation Solution
A printer system that includes a carriage with a detector to scan and detect the edge position of the sheet in the main-scanning direction, allowing for adjustment of the print start position for subsequent scans to maintain image alignment, utilizing a controller to process detection data and adjust the printing device accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a sensor is used to detect sheet position in width direction, then image position alignment is improved, but device complexity increases
Solution Approach 1:
The printing device itself performs the detection function by using its existing scanning capability to detect the edge of the sheet during the printing process, rather than relying on a separate dedicated sensor system. This allows the system to serve multiple functions (printing and detection) with the same hardware components.
Solution Approach 2:
The printing device is designed to perform multiple functions: it both prints images and detects sheet edge positions. By making the printing device universal, the system eliminates the need for separate dedicated detection sensors, thereby reducing device complexity while maintaining detection capability.
2Manufacturing precision
If edge position detection is performed during first scan, then print start position accuracy is improved, but printing time increases
Solution Approach 1:
The edge position detection is performed continuously during the first scan without interrupting the printing process. The printing device detects the sheet edge and simultaneously completes the first scan printing, maintaining continuous useful action rather than stopping to perform detection separately.
Solution Approach 2:
The edge position detection is performed in advance during the first scan before the second scan begins. This preliminary detection allows the system to calculate and adjust the print start position for the second scan beforehand, ensuring accurate positioning without adding time to the overall printing process.
3Manufacturing precision
If print start position is adjusted based on edge position, then image alignment is improved, but control complexity increases
Solution Approach 1:
The system uses feedback from the detected edge position to automatically adjust the print start position for the second scan. The detection result feeds back into the control system, which then modifies the printing parameters to compensate for sheet skew, creating a closed-loop control system that improves alignment automatically.
Data Source
AI summary
A printer includes a printing device to print an image on a sheet, a carriage mounting the printing device, the carriage to scan in a main-scanning direction, a detector on the carriage, the detector to detect a presence and an absence of the sheet, and circuitry to detect an edge position of the sheet in the main-scanning direction based on a detection result by the detector while the printing device prints a first scan of the image on the sheet, adjust a print start position at which the printing device starts printing a second scan of the image on the sheet based on the edge position detected in the first scan, and control the printing device to print the second scan of the image from the print start position.