Printing Control Apparatus Nozzle Management for Density Uniformity

The patent applies local quality by differentiating nozzle usage based on their position in the nozzle row. Central nozzles are prioritized for use while end nozzles are reduced or deactivated based on cartridge elapsed time. This creates a non-uniform usage pattern where different regions of the nozzle row have different operational statuses, thereby maintaining density uniformity in the printed output while preserving adequate printing area coverage through selective nozzle utilization.

The patent implements preliminary action by pre-establishing a predetermined correspondence between nozzle positions and usage priorities before actual printing occurs. The control unit is configured with advance knowledge of which nozzles to prioritize (central nozzles) and which to reduce (end nozzles) based on cartridge elapsed time. This pre-planned nozzle management strategy simplifies real-time control while ensuring consistent ink density, as the system doesn't need to dynamically calculate optimal nozzle selection during printing operations.

The patent converts the harmful effect of pigment settling into a beneficial control mechanism. Instead of attempting to prevent pigment settling (which is difficult in foam-type cartridges), the system accepts settling as inevitable and uses cartridge elapsed time as a metric to proactively adjust nozzle usage. By reducing reliance on nozzles that have been subject to prolonged settling periods, the system transforms the settling phenomenon from a quality defect into a manageable parameter, maintaining density uniformity while preserving the ink containment benefits of foam-type cartridges.