Image Forming Apparatus Nozzle Row Timing Control
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in maintaining discharge position accuracy and image quality when using multiple nozzle rows, particularly due to complex discharge timing control and manufacturing errors in head configurations with overlapping heads.
Innovation Solution
An image forming apparatus with a rotational conveying unit and multiple nozzle rows, where a circuit generates discharge synchronization and timing signals based on detected rotational and conveying amounts to synchronize ink discharge across each nozzle row, improving discharge accuracy and preventing image quality deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple nozzle rows are arranged in the conveying direction to increase productivity, then the productivity is improved, but the discharge position accuracy deteriorates due to complex timing control and manufacturing errors
Solution Approach 1:
The patent implements dynamic discharge timing control that adjusts the discharge timing of each nozzle row based on its actual position and conveysance distance. The control unit calculates individual discharge timings for each nozzle row considering the rotational amount and conveying amount, allowing the system to adapt to manufacturing variations while maintaining high discharge position accuracy across multiple nozzle rows arranged for increased productivity
Solution Approach 2:
The patent changes the discharge timing parameter for each nozzle row individually based on its arrangement position and actual conveying distance. By calculating and applying different discharge timings (td1, td2, td3, etc.) for each nozzle row according to its specific distance from the reference position, the system compensates for manufacturing errors and maintains precise discharge positioning while utilizing multiple nozzle rows for high productivity
2Device complexity
If conventional discharge timing control using constant conveying distance is used, then the device complexity is reduced, but the discharge position accuracy deteriorates when multiple heads are overlapped
Solution Approach 1:
The patent employs feedback mechanisms by detecting the actual rotational amount and conveying amount of the conveying unit, then using this information to calculate and adjust the discharge timing for each nozzle row. This closed-loop feedback approach compensates for manufacturing variations in head positions and conveying distances, maintaining high discharge position accuracy without requiring overly complex mechanical structures
Solution Approach 2:
The patent replaces complex mechanical precision positioning systems with a computational approach. Instead of relying on mechanically precise positioning of multiple heads, the system uses detection signals from rotational and conveying amount sensors, combined with computational timing calculations, to achieve accurate discharge positioning. This substitution of mechanical precision with computational control reduces overall device complexity while maintaining or improving discharge position accuracy
Data Source
AI summary
An image forming apparatus includes a rotational conveying unit for conveying a recording medium by rotating about a rotational axis. A head unit includes n nozzle rows in a conveying direction perpendicular to an axial direction parallel to the rotational axis. Each of the n nozzle rows includes nozzles aligned as a nozzle row in the axial direction. Each n nozzle row is arranged at a distance of d1 to d(n−1) from a predetermined reference nozzle row. A circuit outputs a rotational amount detection signal, and a conveying amount detection signal, and generates a discharge synchronization signal based on the detected rotational amount detection signal and the detected conveying amount detection signal, then generates a nozzle row timing signal based on the distance of the d1 to d(n−1) and the discharge synchronization signal, and generates discharge data based on the discharge synchronization signal and the nozzle row timing signal.