Printhead Ink Deposition Control After Servicing
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Solution Overview
Problem
The build-up of residual ink in printheads due to incomplete ejection, excess ink, and contaminants like dust and paper fibers leads to clogging and impaired print quality, especially with newer inks that are sticky and difficult to service, causing image quality defects during the servicing process.
Innovation Solution
A printing mechanism with a service station equipped with a wiper and capping mechanism that reduces ink deposition immediately after servicing by adjusting the ink amount based on current needs, using a controller to divide the ink deposition across passes and employing masks to compensate for temporary nozzle blockages, ensuring consistent ink delivery and minimizing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the printhead is serviced (cleaned) to remove residual ink buildup, then the nozzle functionality is restored, but image quality defects occur in the zone where printheads are not firing due to sticky ink being pushed or pulled into nozzles
Solution Approach 1:
The system performs preliminary actions by reducing ink deposition in passes immediately before and after servicing. The controller identifies when servicing occurs and adjusts ink deposition accordingly, preventing sticky ink from being forced into nozzles during cleaning operations while maintaining overall print quality
Solution Approach 2:
The system dynamically adjusts ink deposition based on the printing state. The controller monitors servicing events and modifies ink deposition parameters in real-time, reducing ink amount in critical passes and redistributing it across remaining passes to compensate for the reduced deposition
2Strength
If newer sticky inks are used to improve outdoor durability and scratch resistance, then ink longevity and durability are enhanced, but printhead serviceability deteriorates due to difficult cleaning and residual ink buildup
Solution Approach 1:
The system applies preliminary anti-action by reducing ink deposition before servicing operations. This prevents excessive sticky ink from accumulating on the printhead surface during cleaning, making the servicing process easier while maintaining the durability benefits of the sticky ink formulation
Solution Approach 2:
The system changes the ink deposition parameter dynamically based on servicing state. The controller adjusts ink deposition parameters to be lower during and after servicing passes, accommodating the serviceability challenges of sticky inks while preserving their durability advantages in normal printing
3Manufacturing precision
If ink deposition is reduced immediately after servicing to prevent nozzle blockage, then image quality defects are minimized, but the total ink delivery efficiency decreases
Solution Approach 1:
The system dynamically redistributes ink deposition across multiple passes. When a pass has reduced ink deposition due to post-servicing conditions, the controller compensates by increasing ink deposition in subsequent passes, maintaining overall ink delivery efficiency while preventing image quality defects
Solution Approach 2:
The system implements periodic adjustment of ink deposition based on servicing intervals. The controller identifies servicing events and applies reduced ink deposition only in the specific passes immediately affected, while maintaining normal deposition in other passes, thus preserving overall productivity
Data Source
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AI summary
A method for controlling the amount of printing fluid deposited by a printhead for a plurality of passes of a swath width of a printing process is described. The printing process includes periodic servicing of the printhead. The method comprises determining (401 ) an amount of printing fluid to be deposited for each pass of the swath width; identifying (403, 405) which pass of the swath width servicing is to occur; and reducing (413) the determined amount of printing fluid deposited during a first pass immediately following servicing of the printhead.