Inkjet Print Head Distance Detection for Workpiece Contour
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Solution Overview
Problem
Devices for patterning workpieces, such as those made of wood, often produce poor-quality printed images due to imprecise positioning between the print head and the workpiece, leading to issues like overspray and ink mist on adjacent surfaces.
Innovation Solution
The implementation of detection means that maintain a predetermined, fixed relationship with the ink-jet printing means to accurately measure the distance and position of the workpiece, allowing for precise relative positioning and adaptive operation of the printing device, which includes a combination of rough and fine sensors for contour detection and image evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detection means are attached to a conveyor device or portal, then workpiece contour and thickness can be roughly detected, but relative positioning precision between print head and workpiece deteriorates
Solution Approach 1:
A laser sensor serves as an intermediary measurement tool that directly measures the distance between the print head and workpiece surface. This intermediary sensor provides precise relative positioning data without interfering with the printing process, resolving the contradiction between rough detection capability and precise registration requirement
Solution Approach 2:
The patent replaces mechanical positioning systems with optical measurement (laser sensor). Instead of relying on mechanical conveyance precision, the system uses optical distance measurement to achieve sub-millimeter positioning accuracy, substituting mechanical precision requirements with optical measurement capability
2Device complexity
If conventional detection means are used, then device complexity remains low, but print quality deteriorates due to imprecise positioning
Solution Approach 1:
Instead of complexing the entire detection system, the patent applies a simple laser sensor only at the critical location where distance measurement between print head and workpiece is needed. This localized application maintains overall device simplicity while achieving precise positioning at the critical printing interface
Solution Approach 2:
The patent changes the measurement parameter from indirect mechanical positioning to direct optical distance measurement. By measuring the actual distance parameter between print head and workpiece surface in real-time, the system achieves precise positioning without increasing overall device complexity
3Device complexity
If no distance detection is implemented, then device complexity remains low, but harmful effects increase due to overspray and ink mist
Solution Approach 1:
The laser sensor provides real-time feedback on the distance between print head and workpiece surface. This feedback loop allows the printing system to adapt its operation based on actual positioning, preventing overspray and ink mist by ensuring the print head is at the correct distance before and during printing
Solution Approach 2:
The distance measurement is performed preliminarily before printing occurs. By measuring the distance in advance and adjusting positioning accordingly, the system prevents harmful overspray and ink mist before they can occur, rather than attempting to correct them after printing
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
This solution significantly enhances print quality by minimizing deviations caused by conveyance movements and temperature fluctuations, enabling precise positioning and improved image registration, thus preventing overspray and ensuring high-quality printing.
Implementation Method 1
an ink-jet printing means (10) which has a plurality of nozzles (12) for expelling drops of ink
Implementation Method 2
drops of ink from at least one nozzle (12) are expelled
Implementation Method 3
detection means (40) ... to detect at least the distance between the ink-jet printing means (10) and at least one surface to be patterned
Data Source
AI summary
The invention provides a device for patterning workpieces, having: an ink-jet printing means having a plurality of nozzles from which drops of ink can be expelled, a workpiece carrier means for carrying the workpiece to be patterned, a conveyor means for bringing about a relative movement between the workpiece to be patterned and the printing means, and a detection means for detecting the relative position between the ink-jet printing means and at least one surface to be patterned of the respective workpiece to be patterned. The device according to the invention is characterised in that the detection means is disposed and configured so as to be in a predetermined, fixed relationship to the ink-jet printing means and/or to detect at least the distance between the ink-jet printing means and at least one surface to be patterned of the respective workpiece to be patterned, at least during printing.