Image Forming Control for Overlapping Inkjet Head Density
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Solution Overview
Problem
Conventional image forming apparatuses with staggered recording heads experience density differences and streaky noise due to manufacturing errors or positional deviations, leading to black or white streaks in overlapping nozzle regions.
Innovation Solution
The apparatus adjusts ink discharge amounts for both upstream and downstream recording heads at the overlapping nozzle regions based on specific conversion tables, ensuring appropriate density correction by separately calculating and applying correction amounts for each head type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple recording heads are arranged in a staggered manner to form a long line head for one-pass imaging, then recording speed is improved, but density differences and streaky noise occur due to manufacturing errors and positional deviations
Solution Approach 1:
The patent applies local quality by differentiating the treatment of overlapping portions from non-overlapping portions. Specifically, the control unit adjusts ink discharge amounts differently for nozzles in overlapping regions compared to those in non-overlapping regions, compensating for density variations caused by positional deviations only where necessary. This localized adjustment maintains high recording speed while eliminating streaky noise in critical areas.
Solution Approach 2:
The patent changes the parameter of ink discharge amount dynamically based on nozzle position and detected density variations. By modifying the discharge amount parameter for specific nozzles in overlapping portions, the system compensates for manufacturing errors and positional deviations, thereby maintaining uniform image density across the entire recording medium while preserving one-pass high-speed recording capability.
2Manufacturing precision
If ink discharge amounts are adjusted to compensate for density differences, then image density uniformity is improved, but device complexity increases due to additional control mechanisms
Solution Approach 1:
The patent implements feedback by using the image reading unit to detect actual image density and using this information to adjust ink discharge amounts for subsequent recording. The control unit receives density information from the reading unit and automatically modifies discharge parameters to compensate for deviations, creating a closed-loop control system that maintains density uniformity without requiring complex mechanical adjustments.
Solution Approach 2:
The system performs self-service by automatically detecting and correcting its own density variations. The image reading unit monitors the recorded image quality, and the control unit autonomously adjusts ink discharge amounts based on detected deviations, eliminating the need for external manual calibration or complex mechanical adjustment mechanisms.
3Manufacturing precision
If the ratio of ink discharged from upstream and downstream recording heads is changed stepwise to prevent sudden density differences, then image quality is improved, but the risk of streaky noise increases when positional deviations occur
Solution Approach 1:
The patent applies dynamics by making the ink discharge amount adjustable and adaptive rather than fixed. The control unit dynamically modifies discharge amounts based on real-time detection of positional deviations and density variations. This dynamic adjustment allows the system to optimize the ink ratio from upstream and downstream heads for each specific condition, preventing both sudden density differences and streaky noise caused by positional deviations.
Solution Approach 2:
The patent changes the ink discharge parameter dynamically based on detected positional deviations. By adjusting the discharge amount parameter individually for each nozzle in overlapping portions, the system adapts to actual positional relationships, thereby preventing streaky noise that would occur with fixed stepwise ratio changes.
Data Source
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AI summary
To provide an image forming apparatus (1) capable of appropriately adjusting density of an image formed by a nozzle of an overlapping portion (R) of recording heads (240). An inkjet type image forming apparatus (1) including: a test print execution portion (40a) that forms a test image for density detection on a recording medium (P); and a discharge correction amount setting portion (40b) that calculates, for each recording head (240), a difference value between density of an image formed using an end portion nozzle (243) and density of an image formed using a central nozzle (243) from the read density information of the test image, and sets a discharge correction amount per discharge when causing ink to be discharged from the end portion nozzle (243) at the time of executing actual printing on the basis of the difference value, in which the discharge correction amount setting portion (40b) is configured to convert the difference value into the discharge correction amount with reference to a predetermined conversion table in which a first conversion table to be applied to an upstream recording head (240) and a second conversion table to be applied to a downstream recording head (240) are separately set.