Print Head Angle and Stitch Alignment Through Full-Speed Optical Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing inkjet printers face challenges in aligning print heads relative to the velocity of print media motion, especially in roll-fed printers, due to media slip and stretching, which affect pixel spacing and image quality.
Innovation Solution
A printer system that includes a controller, actuators, and a camera to capture optical images of printed test patterns during full-speed operation, allowing for real-time measurement and adjustment of print head alignment based on image data analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If print head alignment is performed using structural printer features, then alignment procedure is simple, but alignment precision deteriorates due to media slip and stretching
Solution Approach 1:
The patent replaces mechanical alignment methods (using structural printer features) with an optical measurement system. A camera captures images of test patterns printed on media, and image processing software analyzes the positions of printed features to calculate print head alignment. This optical approach eliminates the need for physical alignment marks on the printer structure and directly measures alignment relative to media motion, resolving the contradiction between operational simplicity and alignment precision.
Solution Approach 2:
The patent introduces test patterns as an intermediary element between the print heads and the measurement system. These test patterns contain known geometric features that are printed on the media and then captured by a camera. The test patterns serve as a mediator to transfer alignment information from the printing process to the measurement system, enabling precise alignment analysis without direct mechanical reference to printer structure.
2Manufacturing precision
If print head alignment is performed at full speed operation, then alignment precision improves, but device complexity increases
Solution Approach 1:
The patent makes the camera system multi-functional by using it for both quality control (capturing printed images) and alignment measurement (analyzing test pattern geometry). The same image capture and processing infrastructure serves dual purposes: verifying print quality and determining print head alignment, thereby reducing overall system complexity while achieving high-precision alignment at full operating speed.
Solution Approach 2:
The patent implements a feedback loop where the camera captures test pattern images, the processor analyzes alignment based on captured images, and the system adjusts or records alignment status. This feedback mechanism enables continuous monitoring of alignment at full speed operation without requiring separate complex alignment hardware, as the existing image capture and processing systems are utilized for alignment measurement.
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
Enables precise print head alignment relative to media velocity, improving image quality by ensuring accurate placement of ink drops on the media surface.
Implementation Method 1
at least one camera to capture one or more optical images of the print media after the print media passes the plurality of print heads at operating speed
Data Source
AI summary
A printer includes print heads configured to eject ink drops onto print media to form images, a controller connected to the print heads to control the print heads to eject ink drops to form the images including one or more test images, one or more actuators to cause the print media to pass the print heads, and at least one camera to capture one or more optical images of the print media after the print media passes the print heads, the controller to detect the test images in the optical images and to measure print characteristics in the test image. A method of measuring ink jet print head alignment includes capturing one or more optical images of media containing printed images, detecting optical images that contain specific printed test images, and measuring print characteristics based upon image data derived from the specific printed test images.