Scanner Registration Measurement Using Calibration Marks
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Solution Overview
Problem
Current methods for measuring image on paper registration in printing systems are tedious, iterative, and prone to errors, limited by the size of scanners and the precision of manual measurements, which result in long setup times and customer dissatisfaction.
Innovation Solution
A method involving a test sheet with calibration marks and test pattern marks scanned by an image sensing device, where calibration marks are used to determine scanner errors and adjust the positions of test marks for accurate registration measurement, allowing for precise registration analysis with a single scan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If manual measurement methods are used with flexible scales, then measurement can be performed with basic equipment, but the process becomes extremely tedious and time-consuming
Solution Approach 1:
The patent replaces manual mechanical measurement with an automated optical scanning system. The image sensing device captures images of test patterns, and computer processing automatically measures registration errors, eliminating the need for manual measurement with flexible scales and significantly reducing setup time.
Solution Approach 2:
The system performs self-measurement by automatically capturing test pattern images, processing the data, and calculating registration errors without requiring operator intervention for measurement tasks. The computer automatically processes the scanned images and computes registration deviations.
2Volume of moving object
If scanner size is limited, then the device remains compact and manageable, but measurement is limited to sheets smaller than full printer capacity
Solution Approach 1:
The patent divides the measurement process into multiple sequential scans. Large sheets are measured by scanning different regions in sequence, with the computer integrating data from multiple scans to determine overall registration accuracy across the entire sheet surface.
Solution Approach 2:
The system extends measurement capability beyond the physical scan area by using software processing to combine multiple scan results. This allows measurement of sheets larger than the scanner's single-pass capacity through coordinate transformation and data integration.
3Productivity
If only a few points are used for measurement, then the measurement process is simpler and faster, but precision and completeness of error analysis are reduced
Solution Approach 1:
The test pattern includes multiple distributed measurement points across the sheet surface. The system automatically processes all points through optical scanning and computer analysis, providing comprehensive registration error data without requiring manual measurement of each point.
Solution Approach 2:
The automated image sensing and computer processing system efficiently handles large numbers of measurement points that would be impractical to measure manually. The system captures all test pattern points in a single scan and processes them automatically, achieving both high precision and productivity.
4Measurement precision
If scanner calibration is performed to eliminate scanning errors, then measurement accuracy is improved, but an additional time-consuming procedure is required
Solution Approach 1:
The patent combines the calibration marks and test pattern marks into a single test sheet that is scanned once. The computer processing simultaneously performs both calibration (determining scanner geometric errors using calibration marks) and registration measurement (evaluating test pattern marks), eliminating separate calibration procedures.
Solution Approach 2:
The calibration marks are pre-positioned on the test sheet in known locations. During the single scan, the system uses these pre-placed marks to automatically determine and compensate for scanner geometric errors before measuring the test pattern registration, integrating calibration into the measurement process.
5Measurement precision
If edge detection requires overscanning with gaps from sheet edges, then accurate edge detection is possible, but user placement becomes tedious and error-prone
Solution Approach 1:
The patent introduces edge guide features on the platen as intermediaries between the sheet and the scan area. These guides provide physical references that define the scan region boundaries, allowing users to place sheets without needing to create precise gaps. The system detects edges relative to these guides, maintaining accuracy while simplifying operation.
Data Source
AI summary
A method and apparatus for measuring image on paper registration including placing a test sheet of media including a plurality of test pattern marks on a platen of an image sensing device. The platen defines a scan area over which the image sensing device is capable of scanning an image. The image sensing device includes a plurality of calibration marks falling within the scan area. The method further includes operating the scanner to scan the test sheet; determining a scanned position of the calibration marks and a scanned position of the test marks resulting from the scan; comparing the scanned position of the calibration marks with reference position of the calibration marks to determine scanning error; determining an adjusted position of the test marks responsive to the scanning error; and comparing the adjusted test mark positions with predetermined reference positions to measure registration accuracy. An edge guide disposed on the platen assists in aligning the test sheet for scanning.