Nozzle Recirculation Control for Printing Systems
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Solution Overview
Problem
The evaporation of solvents from printing fluids at nozzles in printing systems leads to reduced image quality in 2D printing and reduced effectiveness in 3D printing, causing fluid to dry out and alter droplet trajectories, velocities, and shapes, which increases the computational and communication bandwidth burden on printer controllers due to intensive pre-processing for recirculation commands.
Innovation Solution
A local recirculation controller within the printhead determines whether to perform recirculation of nozzles, reducing the processing burden on the printer controller and communication bandwidth by allowing the printhead to manage recirculation decisions independently, using a sampling time interval and recirculation enable indication without address data, integrated into print packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the printer controller performs intensive pre-processing to determine recirculation commands for each nozzle, then recirculation control accuracy is improved, but processing load and communication bandwidth burden increase
Solution Approach 1:
The system divides recirculation control into two segments: (1) The printer controller sends simplified timing information (sampling time interval and recirculation enable indication) without detailed nozzle address data; (2) The printhead's local controller independently determines which specific nozzles require recirculation based on local timing analysis. This segmentation reduces communication bandwidth while maintaining control accuracy.
Solution Approach 2:
The printhead is empowered with self-service capability to autonomously determine recirculation commands for its nozzles based on received timing information. The local controller within the printhead analyzes the sampling time interval and recirculation enable indication to independently generate appropriate recirculation commands, eliminating the need for the printer controller to process and send detailed recirculation instructions for each nozzle.
2Measurement precision
If recirculation commands are sent with detailed address data for each nozzle, then recirculation precision is improved, but communication bandwidth consumption increases
Solution Approach 1:
The patent extracts the detailed nozzle address data from the recirculation command transmission path. Instead of sending complete recirculation commands with individual nozzle addresses from the printer controller, only essential timing parameters (sampling time interval and recirculation enable indication) are transmitted. The extraction of address data from the communication stream significantly reduces bandwidth consumption while preserving recirculation precision through local determination.
3Stability of the object's composition
If the printhead processes recirculation decisions centrally controlled by the printer controller, then system coordination is improved, but processing time and bandwidth increase
Solution Approach 1:
The printer controller performs preliminary action by sending the sampling time interval and recirculation enable indication before the printhead needs to make recirculation decisions. This preliminary transmission of timing framework allows the printhead's local controller to independently and rapidly determine recirculation commands without real-time coordination overhead, reducing processing time while maintaining system coordination through the pre-established timing parameters.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces the processing load on the printer controller and communication bandwidth, enabling efficient fluid recirculation management within the printhead, thereby maintaining high-quality image formation and effective 3D object creation without the need for extensive pre-processing and communication.
Implementation Method 1
Each nozzle includes a heating element that when activated generates heat to vaporize a printing fluid in a firing chamber of the nozzle, which causes expulsion of a droplet of the printing fluid from the nozzle
Implementation Method 2
recirculation can include circulating fresh fluid through a firing chamber of a nozzle
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
In some examples, a fluid ejection device includes a nozzle to dispense fluid, and a recirculation controller to control recirculating of the nozzle. The recirculation controller is to receive, from a fluid ejection controller, an indication corresponding to a start of a sampling time interval, determine, during the sampling time interval, whether a firing event corresponding to firing of the nozzle has occurred, and in response to determining that the firing event has not occurred, cause activation of a recirculation pump to recirculate fluid through a chamber of the nozzle.