Printbar Registration via Pseudo-Random Dot Pattern Detection
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Solution Overview
Problem
Existing page-wide array printers face registration errors due to media expansion, slippage, and mechanical imperfections, leading to poor image quality, and existing registration systems are complex, expensive, and difficult to scale.
Innovation Solution
A method involving the printing of a sparse, pseudo-random dot pattern on the media as a reference, detected by an image sensor, which is used to configure nozzle data for subsequent images, allowing for accurate registration and compensation for media movement and misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If encoders are attached to mechanical elements of media transport to enable registration, then registration capability is provided, but registration errors still occur due to media expansion, slippage, and mechanical imperfections
Solution Approach 1:
The patent replaces mechanical encoder systems with an optical detection system. Instead of using encoders attached to mechanical media transport elements, the system uses an optical sensor to detect a pattern printed on the media itself. This substitution eliminates the mechanical link between the transport system and position measurement, thereby eliminating registration errors caused by media expansion, slippage, and mechanical imperfections.
Solution Approach 2:
The patent introduces a printed pattern as an intermediary between the media transport system and the position measurement system. The pattern is printed on the media and detected by an optical sensor, serving as a mediator that directly reflects the media's actual position and state, bypassing the unreliable mechanical encoder system.
2Measurement precision
If complex optical imaging systems are used to analyze test patterns for registration, then registration accuracy is improved, but system complexity and cost increase
Solution Approach 1:
The patent uses a simple, inexpensive printed pattern (test pattern) as the registration reference instead of complex optical imaging systems. The pattern is printed on the media using the existing printbar system and detected by a simple optical sensor, eliminating the need for expensive calibration equipment and complex optical imaging systems.
Solution Approach 2:
The patent makes the printing system itself serve the registration function by printing the test pattern using the same printbar hardware. This self-service approach eliminates the need for separate, dedicated optical imaging systems for registration, reducing overall system complexity and cost.
3Manufacturing precision
If existing registration systems are implemented, then image component alignment is improved, but the systems are difficult to scale to larger printing systems
Solution Approach 1:
The patent creates a universal registration system that works across different printing system configurations. The test pattern printing and detection mechanism is integrated into the general printing process, allowing the same system to handle various media sizes, transport speeds, and printbar configurations without requiring system-specific calibration equipment or complex setup procedures.
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 provides robust and accurate image registration, insensitive to media expansion and slippage, and is scalable and cost-effective, eliminating the need for complex optical detectors and expensive registration systems.
Implementation Method 1
detected by an image sensor
Data Source
AI summary
A method and system of controlling at least one printbar in a printing system are described. The printing system has one or more of printbars distributed along a media transport. A first image including a reference pattern is generated on a print medium with a first printbar. A pattern is then detected on the print medium. The reference pattern and the detected pattern are used to determine a position of the first image relative to a second printbar. This position is used to configure nozzle data for a second image to be generated on the print medium by the second printbar.