Raster Graphic Data Correction for Printing Registration Errors
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Solution Overview
Problem
Printing processes face registration errors due to deformation of the recording medium, particularly paper shrinkage caused by heat treatment, leading to misalignment and incomplete printing, especially in book production and color printing, where mechanical adjustments are complex and existing methods result in artifacts or incomplete compensation.
Innovation Solution
A method that processes raster graphic data along an image processing axis corresponding to the deformation axis, calculating target pixels from multiple adjacent source pixels to minimize artifacts, and optionally using stochastic pixel selection to avoid equidistant omissions, allowing for effective shrinkage correction in software during the raster image processing stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the recording medium is subjected to heat treatment for drying ink, then the ink drying efficiency is improved, but the paper shrinks causing registration errors
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing deformation amount data before the actual printing process. The system measures paper deformation characteristics in advance and creates a correction map that is applied during raster image processing, allowing the printing system to compensate for shrinkage effects before they occur during heat treatment.
Solution Approach 2:
The patent changes parameters by modifying the raster graphic data based on measured deformation characteristics. The system adjusts pixel positioning and spacing in the digital image data to compensate for expected paper shrinkage, transforming the parameters of the digital representation to match the physical deformation that will occur during printing and drying.
2Manufacturing precision
If mechanical adjustments are made to correct registration errors, then the registration accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent replaces mechanical adjustment systems with a software-based solution. Instead of using complex mechanical devices to physically adjust print head positions or paper feeding mechanisms, the system uses raster image processing to digitally transform the image data, compensating for deformation through computational methods rather than mechanical intervention.
Solution Approach 2:
The patent creates a digital copy or model of the paper deformation characteristics by measuring and storing deformation amount data. This digital representation of the deformation is then used to transform the raster graphic data, allowing the system to work with a virtual model of the deformation rather than directly manipulating physical components.
3Manufacturing precision
If the paper shrinkage is compensated by adjusting print head position, then the registration error is reduced, but the productivity decreases due to additional adjustment time
Solution Approach 1:
The patent performs compensation calculations in advance during the raster image processing stage, before the actual printing occurs. By pre-transforming the image data with the appropriate deformation compensation, the system eliminates the need for time-consuming adjustments during the printing process itself, maintaining high productivity while achieving accurate registration.
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 effectively reduces registration errors by retaining information from source pixels in target pixels, minimizing artifacts, and allowing for decoupled deformation correction from the RIP process, ensuring accurate and complete printing despite paper shrinkage.
Implementation Method 1
the recording medium is subjected to a treatment by which the recording medium and the first printed image deform by a deformation factor along at least one deformation axis
Implementation Method 2
a heat treatment takes place between the printing processes
Implementation Method 3
the shrinking effect of the paper can be particularly strong due to the strong moisture absorption of paper in the course of printing with the ink and the subsequent drying process for the ink
Implementation Method 4
Paper is a hygroscopic material that emits water vapor upon heating and stores water again upon cooling
Implementation Method 5
Paper is a hygroscopic material that emits water vapor upon heating and stores water again upon cooling
Data Source
AI summary
In a method to correct a registration error in a printing process, data of first and second images to be printed are subjected to a raster image process via which at least first and second raster graphics are generated. Control data for a print member or two respective print members are formed from the first and the second raster graphics. A recording medium is printed in a first printing process with the control data of the first image. The recording medium is subjected to a treatment via which the recording medium and the first image deform along at least one deformation axis. The recording medium is printed by the print member with the control data of the second image in a second printing process. To avoid a registration error between the first and second printed images, the control data of the respective raster graphic of at least one of the first and the second print images as a source image are processed along an image processing axis of the respective raster graphic that corresponds to the deformation axis, and wherein respective source pixels to be used for the respective raster graphic are selected stochastically from the source image in a direction transverse to the image processing axis.