Printing Head Distance Control for Large Stationary Surfaces
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Solution Overview
Problem
Existing printing technologies are unable to effectively print large, stationary surfaces such as building walls, truck sides, or container surfaces without requiring significant effort and cost due to limitations in substrate alignment, height, and surface curvature, as well as the inability to print on uneven or tilted surfaces.
Innovation Solution
A method and device that adjust the printing head's distance from the surface using non-contact measurement and a control unit to maintain a consistent distance, allowing for printing on curved and tilted surfaces by distributing measurement points based on surface evenness and using a steerable moving frame and extendable axes to accommodate varying surface profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a fixed-length y-axis with a toothed belt is used for print head motion, then the printing device can be manufactured with standard components, but the printable height is limited and cannot be extended for taller walls
Solution Approach 1:
The y-axis is designed as an extendable structure that can dynamically adjust its length. The axis comprises multiple sections that can be extended or retracted based on the required printable height, allowing the device to adapt to different wall heights while maintaining mechanical stability through proper support structures.
Solution Approach 2:
The y-axis is divided into multiple modular sections that can be independently adjusted. This segmentation allows the axis to be extended in discrete increments, accommodating various printable heights without requiring a completely different mechanical design for each height requirement.
2Adaptability or versatility
If the moving frame moves in a straight line on rails, then the mechanism is simple and stable, but curved surfaces cannot be printed
Solution Approach 1:
The moving frame is equipped with steerable wheels that can dynamically adjust their direction of motion. This allows the frame to follow curved paths along the wall surface while maintaining stable movement, enabling printing on curved surfaces without requiring complex curved rail systems.
Solution Approach 2:
Sensors are integrated into the moving frame to detect the wall surface geometry in real-time. This feedback information is used to dynamically adjust the steering of the wheels, enabling the frame to automatically adapt to curved surfaces and maintain proper printing head positioning throughout the printing process.
3Manufacturing precision
If ultrasonic sensors are attached to the printing head for distance measurement, then real-time distance detection is possible, but repositioning is incomplete due to dead time between measurement and adjustment
Solution Approach 1:
The distance measurement is performed in advance at predetermined positions along the print track before the printing head arrives at those positions. This preliminary measurement allows the system to calculate and prepare the necessary repositioning movements ahead of time, eliminating dead time and ensuring continuous precise positioning throughout the printing process.
Solution Approach 2:
The system replaces real-time continuous adjustment with a pre-calculated positioning approach. By measuring distances in advance and using computational methods to determine optimal head positions, the system achieves precise positioning without the delays associated with continuous real-time feedback and mechanical adjustment during printing.
4Adaptability or versatility
If the printing head is fixed at a constant distance from the surface, then the ink jet focusing is simple and precise, but the device cannot accommodate uneven or tilted surfaces
Solution Approach 1:
The printing head is mounted on an adjustable mechanism that can dynamically change its distance from the wall surface. This dynamic adjustment capability allows the printing head to maintain optimal spacing from uneven or tilted surfaces while keeping the ink jet focusing system relatively simple, as adjustments are made in discrete steps rather than continuous real-time modification.
Data Source
AI summary
A method and a device as provided for printing a large surface which is situated, in particular, on a substrate which cannot be fed to a printing device. The method is distinguished by the fact that the perpendicular spacing Azo of a reference point of the device at a plurality of points which are distributed over the printing web from the surface to be printed is determined in each case at the points which are distributed over the printing web, and the perpendicular spacing Az of the print head from the surface to be printed is set in accordance with a previously recorded measured value. Here, the plurality of points can be distributed uniformly over the length of the printing web. The device for carrying out the method has a measuring device for contactless measurement of the spacing between a reference point of the device and the surface to be printed. Furthermore, the device has a control unit for evaluating the measured values and producing control pulses for setting the spacing Az of the print head from the surface to be printed.