Printhead Collision Avoidance Using Optical Detection
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Solution Overview
Problem
Industrial inkjet printers face challenges in detecting and avoiding small obstacles and defects on the printing medium during operation, which can cause collisions and damage to the printhead, especially in large-size printers where manual inspection is tedious and costly, and existing obstacle detection systems are inadequate for real-time collision avoidance.
Innovation Solution
An automated system using a combination of light-based detection methods, including semiconductor lasers and photoelectric cells, along with image processing, to identify potential obstacles on the printing medium, allowing for timely avoidance actions such as halting the printhead movement or retracting it from the medium, and incorporating ultrasonic or X-ray detection for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual inspection methods are used to detect obstacles on the printing medium, then the system is simple to implement, but the detection accuracy is insufficient and the process is tedious and costly
Solution Approach 1:
The patent replaces manual mechanical inspection with automated optical detection systems including laser scanners and photoelectric sensors. These systems use light reflection and absorption principles to automatically detect obstacles on the printing medium, eliminating the need for tedious manual inspection while significantly improving detection accuracy and enabling real-time obstacle identification during the printing process.
Solution Approach 2:
The patent introduces intermediate detection devices such as laser beams and photoelectric cells that act as mediators between the printing system and obstacles. These intermediaries detect obstacles indirectly through light interaction (reflection, absorption, scattering) without direct contact, enabling non-intrusive, high-precision detection that bridges the gap between simple manual inspection and complex direct measurement.
2Speed
If existing obstacle detection systems are used, then the system structure is relatively simple, but real-time collision avoidance capability is inadequate
Solution Approach 1:
The patent implements preliminary obstacle detection by positioning detection devices such as laser scanners and photoelectric sensors upstream of the printhead path. These systems detect obstacles before the printhead reaches them, providing advance warning that triggers automatic printhead retraction or path adjustment. This preliminary action ensures real-time collision avoidance by preparing the system in advance rather than reacting after collision risk materializes.
Solution Approach 2:
The patent establishes a closed-loop feedback system where detection devices continuously monitor the printing medium and immediately communicate obstacle information to the control system. The control system processes this feedback in real-time and automatically adjusts printhead position or halts operation when obstacles are detected. This rapid feedback mechanism ensures high reliability in collision avoidance by continuously adapting system behavior based on current detection data.
3Productivity
If the printhead operates at high speed over long distances, then printing productivity is improved, but the risk of collision damage from obstacles increases
Solution Approach 1:
The patent positions multiple detection devices including laser scanners and photoelectric sensors along the printhead travel path to detect obstacles before the high-speed printhead reaches them. When obstacles are detected in advance, the system automatically triggers printhead retraction or path adjustment, allowing the printhead to maintain high operating speeds while avoiding collision damage through preemptive obstacle identification and response.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively prevents collisions and damage to the printhead by accurately detecting small obstacles and defects during printing, enabling continuous operation and reducing maintenance costs by automating the obstacle avoidance process.
Implementation Method 1
a combination of light-based detection methods, including semiconductor lasers and photoelectric cells
Implementation Method 2
incorporating ultrasonic or X-ray detection for enhanced accuracy
Implementation Method 3
incorporating ultrasonic or X-ray detection for enhanced accuracy
Data Source
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AI summary
To avoid possible damaging collisions of a printhead with small receiver defects and other obstacles in a digital printer using a printhead mounted on a scanning shuttle for recording am image on a receiver while scanning along the receiver, a method using the following steps is used: - sensing for possible obstacles having a size smaller and larger than the inkjet head-receiver clearance distance in an area of the receiver to be scanned over by the printhead using a sensor system mounted on the scanning shuttle, - avoiding a collision of the printhead with the obstacle when an obstacle is sensed. Preferably an evaluation step is include to evaluate is a detected obstacle is evaluated to be potentially damaging. A system for using the steps is also disclosed.