Multipass Inkjet Printhead Nozzle Usage Distribution
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Solution Overview
Problem
Conventional multipass print modes in inkjet printers are unsatisfactory due to limited nozzle usage, leading to suboptimal printhead reliability and increased risk of nozzle failure from evaporation and clogging, as a substantial part of the nozzles remain inactive during printing.
Innovation Solution
A method and apparatus for a multipass print mode that efficiently distributes nozzle usage across printheads, allowing a substantial part of the nozzles to be utilized in each printhead, with an error-hiding mechanism to compensate for failing nozzles by shifting the print medium and reallocating nozzle usage, thereby improving image quality and printhead reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multipass print mode is used with limited nozzle usage, then printing can be completed, but printhead reliability deteriorates due to evaporation and clogging of inactive nozzles
Solution Approach 1:
The patent implements dynamic nozzle allocation where the set of active nozzles changes between passes. Nozzles are selectively activated and deactivated based on the specific printing requirements of each pass, allowing the system to adapt nozzle usage patterns dynamically. This prevents prolonged inactivity of specific nozzles while maintaining printing flexibility.
Solution Approach 2:
The patent ensures continuous useful action by designing multiple passes such that different sets of nozzles are actively used in each pass. This continuity strategy ensures that nozzles remain engaged in printing operations across successive passes, preventing the harmful effect of prolonged inactivity that leads to evaporation and clogging.
2Manufacturing precision
If only a fraction of total ink drops are deposited in each pass, then multipass printing is achieved, but image quality deteriorates due to incomplete coverage and unprinted areas
Solution Approach 1:
The patent segments the complete image into multiple passes, with each pass responsible for depositing specific portions of ink drops. The image is divided such that different nozzle sets handle different spatial regions or density requirements in each pass, and subsequent passes complete the remaining areas, ensuring full coverage through systematic segmentation.
Solution Approach 2:
The patent introduces a temporal dimension to the printing process by distributing ink deposition across multiple passes. Instead of attempting to deposit all ink in a single pass, the system uses sequential passes at different time points, allowing complete coverage while managing the complexity of ink deposition through time-based distribution.
3Device complexity
If a substantial part of nozzles remain inactive during printing, then device complexity is reduced, but harmful factors increase due to evaporation and clogging
Solution Approach 1:
The patent applies preliminary action by planning the sequence of passes and nozzle activation in advance. The printing system pre-determines which nozzles will be active in each pass to ensure optimal coverage while minimizing idle time. This preliminary planning prevents nozzle inactivity and the associated harmful effects of evaporation and clogging.
Solution Approach 2:
The patent implements feedback mechanisms to monitor nozzle performance and adjust activation patterns. By tracking which nozzles are functioning properly and which are at risk of clogging or evaporation, the system can dynamically adjust which nozzles are activated in subsequent passes, preventing harmful effects while maintaining printing quality.
Data Source
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AI summary
The present disclosure relates particularly but not exclusively to a method for printing in a multipass print mode using a first printhead (PT1) and a second printhead (PT2), the method including printing in a first pass a first image in a first area of a print medium using a first set (ST21) of nozzles (N5-N24) from the first printhead (PT1), printing in a second pass a coating layer over the first image using a second set (ST22) of nozzles (P4-P22) from the second printhead (PT2), and printing in a third pass a second image over the coating layer using a third set (ST23) of nozzles (Nl-20) from the first printhead (PT1).