Printhead Roll Detection Using Simultaneous Inkjet Marking
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Solution Overview
Problem
Existing methods for detecting and calibrating printhead roll in inkjet printers are inefficient due to errors caused by small movements of the image receiving member, leading to skewed images and ineffective correction of printhead alignment.
Innovation Solution
A method involving simultaneous operation of multiple inkjets to form marks on an image receiving member, using an optical sensor to generate image data and calculate cross-process direction distances to identify the angular orientation of the printhead, allowing for precise detection and correction of printhead roll.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the image receiving member moves during test pattern printing, then the printing process can continue, but measurement precision deteriorates due to errors in printed test patterns
Solution Approach 1:
The system captures multiple images of the test pattern at different positions along the process direction before completing the full printing cycle. By preliminarily capturing these images during the printing process rather than after, the system can detect printhead roll without requiring the image receiving member to be completely stationary during measurement.
Solution Approach 2:
The system uses the captured images to calculate cross-process direction distances between marks from different inkjets, then feeds this information back to determine the actual printhead roll angle. This feedback mechanism allows continuous adjustment and compensation during the printing process, maintaining both productivity and measurement precision.
2Reliability
If multiple images are captured at different positions, then measurement reliability improves through data averaging, but loss of time increases due to multiple capture cycles
Solution Approach 1:
The system captures images continuously during the printing process rather than stopping to take separate measurements. Multiple images are captured at different positions along the process direction as part of the normal printing operation, eliminating idle time and maintaining continuous productive action while gathering multiple data points for reliable 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
This approach enables accurate detection and compensation for printhead roll, improving image alignment and reducing errors in printed images by using simultaneous inkjet operations and optical data analysis.
Implementation Method 1
an optical sensor configured to generate image data corresponding to light reflected from the image receiving member
Data Source
AI summary
A method for aligning a printhead to compensate for printhead roll has been developed. The method includes simultaneously operating a plurality of inkjets in a printhead to eject ink drops to form a plurality of marks on an image receiving member. A plurality of cross-process direction distances between one mark formed by a reference inkjet and each of the marks formed by the other inkjets is identified. A magnitude of a difference between an angular orientation of the printhead and the cross-process direction with reference to the plurality of identified cross-process direction distances indicates any printhead roll.