Printer Y-Bar Conveying Accuracy via Direct Measurement
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Solution Overview
Problem
Large flatbed inkjet printers experience mechanical backlash, expansion, and contraction issues with long Y-bars, leading to discrepancies in movement calculations and decreased conveying accuracy, which affects the positioning of ink droplets and overall image quality.
Innovation Solution
A printer design with a Y-bar that includes a drive mechanism and measuring device to directly measure movement, allowing for correction of controlled variables, and independent drive mechanisms for each end of the Y-bar to adjust tilt and equalize movement, using a timing belt and pulley system for cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the Y-bar length is increased to accommodate large flatbed printers, then the printing area is improved, but mechanical backlash, expansion, and contraction occur leading to decreased conveying accuracy
Solution Approach 1:
The Y-bar is divided into multiple sections that can be independently adjusted. The measuring devices are positioned at multiple locations along the Y-bar to detect local position deviations. This segmentation allows the system to compensate for expansion, contraction, and twisting of the long Y-bar by adjusting individual sections, thereby maintaining conveying accuracy across large printing areas.
Solution Approach 2:
Multiple measuring devices are installed along the Y-bar to directly detect the actual position of the Y-bar at various points. The control device receives this feedback information and calculates the discrepancies caused by mechanical backlash, expansion, and contraction. Based on this feedback, the control device adjusts the controlled variables of the drive mechanism to correct position deviations, thereby maintaining high conveying accuracy despite the long Y-bar length.
2Device complexity
If a single motor drive mechanism is used for the Y-bar, then device complexity is reduced, but positioning accuracy of the head unit decreases due to mechanical discrepancies
Solution Approach 1:
Multiple measuring devices are introduced as intermediaries between the single motor drive mechanism and the Y-bar position control. These measuring devices directly detect the actual position of the Y-bar and provide feedback to the control device, which then adjusts the drive mechanism's controlled variables. This intermediary measurement and feedback system compensates for the limitations of the single motor drive, maintaining high positioning accuracy without significantly increasing drive mechanism complexity.
3Device complexity
If indirect calculation of Y-bar movement is used via encoder, then device complexity is minimized, but discrepancy occurs between calculated and actual movement reducing conveying accuracy
Solution Approach 1:
The patent replaces the indirect mechanical calculation method (encoder on motor shaft) with direct measurement using measuring devices that physically contact or optically detect the actual position of the Y-bar. This substitution eliminates the discrepancy between calculated and actual movement by directly measuring the Y-bar's position, thereby improving conveying accuracy while accepting increased measurement system complexity.
Data Source
AI summary
A printer is provided to improve the conveying accuracy of a Y-bar, thus improving printed image quality. The printer includes the Y-bar that extends in a first direction above a flatbed on which a medium is mounted, holds an ink droplet ejecting head unit so that the head unit is movable in the first direction, and is held so as to be movable with respect to the flatbed in a second direction perpendicular to the first direction. The printer includes a drive mechanism that conveys the Y-bar in the second direction, a drive control device that carries out a drive control of the drive mechanism, and a measuring device that directly measures an amount of movement of the Y-bar with respect to the flatbed. The drive control device corrects controlled variables of the drive mechanism based on the amount of movement of the Y-bar measured by the measuring device.