Printing Apparatus Positional Deviation Correction via Halftone Synthesis
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Solution Overview
Problem
Conventional printing apparatuses face high processing loads due to the need for rapid data processing and transfer to correct positional deviations during printing, leading to increased costs and memory requirements, especially in nonvariable printing methods where the same image data is used across pages.
Innovation Solution
A printing apparatus that creates pairs of shift image data assuming positive and negative positional deviations, performs shading correction, and generates halftone dot processes to produce halftone common and difference image data, which are stored and synthesized based on detected positional deviations to reduce processing load without increasing memory requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If shift image data is created and transferred for each positional deviation detection, then positional deviation correction is achieved, but processing load and data transfer requirements increase significantly
Solution Approach 1:
The patent pre-calculates and stores shift image data for multiple possible positional deviations in a lookup table before actual printing occurs. During printing, the system only needs to retrieve the pre-computed data corresponding to the detected deviation amount, rather than performing real-time complex data processing and transfer operations for each deviation correction.
2Manufacturing precision
If high-speed data processing and transfer is implemented for positional deviation correction, then correction accuracy is maintained, but apparatus cost increases
Solution Approach 1:
The system performs all complex image data processing and shift calculations in advance during setup, storing the results in a lookup table. During actual printing operations, the system simply retrieves pre-computed data from memory based on detected deviation amounts, eliminating the need for expensive high-speed processing hardware during runtime.
Solution Approach 2:
Instead of creating and transferring new shift image data in real-time, the system uses pre-generated copies of shifted image data stored in a lookup table. This approach replaces complex real-time data processing with simple data retrieval operations, reducing hardware requirements and apparatus cost.
3Adaptability or versatility
If multiple shift image data are prepared and stored for different positional deviations, then correction capability is improved, but memory requirements increase significantly
Solution Approach 1:
The patent stores shift image data selectively based on actual detected positional deviations rather than preparing all possible shift combinations in advance. The lookup table contains only the necessary shift data corresponding to the range of deviations actually observed during printing operations, optimizing memory usage while maintaining adequate correction capability.
Data Source
AI summary
An image shifter creates plural pairs of shift image data. A shading corrector and a halftone dot processor create halftone shift image data from shift images. Further, a difference image creator creates halftone common image data which is a common part of a pair of halftone shift image data, and creates halftone positive difference image data and halftone negative difference image data each of which is a difference between the halftone common image data and one of a pair of halftone shift image data. A composite image creator synthesizes the halftone common image data corresponding to an amount of positional deviation, and the halftone positive difference image data or halftone negative difference image data. A controller executes printing on web paper. Since the image data is only synthesized, processing load can be lightened even if printing is performed to restrain positional deviations.