Print Medium Length Detection for Accurate Duplex Image Alignment
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Solution Overview
Problem
Printing apparatuses face issues with variations in print medium size leading to deviations in image positioning on both sides of a sheet and misalignment during cutting due to dimensional tolerances in paper sheets, causing discrepancies in print data alignment.
Innovation Solution
A printing apparatus with a detecting unit to measure the length of the print medium, calculate an average length, and adjust the print starting position based on this measurement to minimize deviations in image positioning on both sides of the sheet and ensure accurate cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If printing is performed using a default print starting position on paper sheets with size variations, then the printing process is simple and fast, but the center position of each paper sheet and the center position of the printed image are deviated
Solution Approach 1:
The system performs preliminary detection of the paper sheet's actual size and position before printing begins. The detection unit measures the paper sheet dimensions, and the controller calculates the appropriate print starting position in advance, ensuring accurate image positioning without compromising printing speed.
2Productivity
If paper sheets with size variations are cut after printing, then the printing process is efficient, but there is a variation in the distance from the cut position to the writing start position
Solution Approach 1:
The detection unit provides feedback information about the actual paper sheet size and position to the controller. Based on this feedback, the controller dynamically adjusts the print starting position and cutting position calculations, ensuring that both printing and cutting operations are precisely aligned despite paper sheet variations.
3Adaptability or versatility
If printing is performed on both sides of paper sheets with size variations, then the printing apparatus can utilize both surfaces, but the images on the front and back surfaces are printed slightly deviated from each other
Solution Approach 1:
Before printing on both sides of the paper sheet, the system performs preliminary detection of the paper sheet's actual dimensions and position. The controller calculates the appropriate print starting positions for both the front and back surfaces in advance, ensuring that images on both sides are accurately aligned despite paper sheet size variations.
4Manufacturing precision
If the print starting position is adjusted based on detected paper sheet length, then image positioning accuracy is improved, but the printing process requires additional detection and calculation steps
Solution Approach 1:
The detection unit automatically detects the paper sheet's actual size and position, and the controller autonomously calculates and adjusts the print starting position without requiring manual intervention. This self-service mechanism maintains high positioning accuracy while minimizing the need for complex manual adjustment systems.
Data Source
AI summary
A printing apparatus includes: an accommodating unit accommodating a print medium; a first conveying unit picking up the print medium from the accommodating unit and conveying the print medium along a first conveying direction; a printing unit printing, on the print medium, print data included in a print job; a first detecting unit detecting front and rear ends in the first conveying direction of the print medium conveyed by the first conveying unit; and a controller. The controller executes: a length calculating process of calculating a print medium length as a length in the first conveying direction of the print medium; a setting process of setting a print starting position as a position at which printing is to be started in the printing unit; and a first printing process based on the print starting position set in the setting process.