Inkjet Image Processing for Banding Suppression via Nozzle Jetting Rate Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image processing methods for serial-type ink jet printers face challenges in suppressing banding and color unevenness while maintaining productivity, as they often require extra scanning and result in non-uniform nozzle jetting rates that lead to uneven dot disposition and overlap probabilities.
Innovation Solution
An image processing apparatus that generates dot data by converting gradation values to reflect different nozzle jetting rates for end and central nozzles, ensuring uniformity in nozzle jetting rates across the nozzle row, thereby controlling the dot disposition for each color to minimize banding and color unevenness without decreasing productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mask pattern methods are used to control nozzle usage rates, then banding is suppressed, but printing speed decreases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal nozzle selection patterns and jetting rate adjustments before printing begins. The image processing apparatus pre-processes image data to determine which nozzles should be used and at what rates, storing this information in lookup tables or pre-computed data structures. During actual printing, the system simply retrieves and applies these pre-determined patterns, avoiding real-time calculations that would slow down printing speed while still achieving effective banding suppression.
2Manufacturing precision
If non-uniform nozzle jetting rates are applied to end and central nozzles, then banding is reduced, but dot disposition uniformity deteriorates
Solution Approach 1:
The patent applies local quality by implementing different jetting rate characteristics for different spatial locations of nozzles. Specifically, end nozzles (first and second nozzles) are assigned different jetting rates compared to central nozzles (third and fourth nozzles). The image processing apparatus adjusts the jetting amount of end nozzles relative to central nozzles based on pre-determined correction values stored in memory, allowing each nozzle group to operate with optimized local characteristics that suppress banding while maintaining overall dot disposition uniformity through compensatory adjustments.
3Manufacturing precision
If extra scanning is performed to control dot disposition, then image quality improves, but productivity decreases
Solution Approach 1:
The patent applies parameter changes by modifying the jetting rate parameter of specific nozzles rather than adding extra scanning operations. The image processing apparatus changes the jetting amount parameter (volume, frequency, or timing) of end nozzles relative to central nozzles based on pre-stored correction data. This parameter adjustment allows the system to achieve uniform dot disposition and high-quality image output using the same number of scanning passes, thereby maintaining productivity while improving image quality through precise control of ink deposition parameters.
Data Source
AI summary
Provided are an image processing apparatus, an image processing method, a program, and an image recording apparatus capable of suppressing occurrence of banding and color unevenness without productivity decrease. Different types of nozzle jetting rates are reflected in image data of each of a first color and a second color that are two different plural colors to perform conversion of a gradation value of each pixel, and halftone processing is performed with respect to the converted image data. A first nozzle jetting rate to be reflected in a gradation value of the first color is set so that a nozzle jetting rate of an end part nozzle at each of both end parts of a nozzle row is suppressed to be smaller than a nozzle jetting rate of a central nozzle. A second nozzle jetting rate to be reflected in a gradation value of the second color has a smaller difference between the nozzle jetting rate of the end part nozzle and the nozzle jetting rate of the central nozzle compared with the first nozzle jetting rate.