Inkjet Printer Circulation Path Control for Viscosity Management
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Solution Overview
Problem
Inkjet printing apparatuses face issues with ink viscosity increase due to water evaporation, leading to faulty ink discharge and inability to re-circulate ink from nozzles, especially when temperature retention causes early-stage viscosity increase in unused nozzle rows.
Innovation Solution
A printing apparatus with a control unit that determines which circulation paths to use based on print data, circulating ink to maintain optimal viscosity and prevent concentration, using a circulation mechanism and multiple discharge ports with liquid chambers to manage ink flow and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ink is circulated to remove concentrated ink from the nozzle, then ink discharge reliability is improved, but water evaporation continues to increase viscosity and cause concentration in the circulation path
Solution Approach 1:
The circulation path is divided into multiple independent paths, each dedicated to a specific color ink. This segmentation allows each path to be optimized for its specific ink's evaporation characteristics and circulation needs, preventing cross-contamination of evaporated water between different color paths while maintaining effective circulation for each color.
Solution Approach 2:
The system dynamically adjusts circulation based on print data, determining which paths to activate and at what rates. This dynamic control allows the system to adapt circulation patterns to actual printing requirements, preventing unnecessary circulation that would cause water evaporation and concentration, while ensuring adequate circulation when needed.
2Quantity of substance
If all ink paths are circulated simultaneously, then ink concentration is reduced, but temperature retention and evaporation cause viscosity increase in unused nozzle rows
Solution Approach 1:
Each circulation path is independently controlled based on local printing requirements. Unused paths can be kept at lower temperatures or stopped entirely, while active paths receive adequate circulation to maintain optimal temperature and prevent concentration. This local quality control prevents unnecessary temperature retention and evaporation in unused nozzle rows.
Solution Approach 2:
Instead of circulating all ink paths simultaneously, the system applies partial circulation only to paths needed for current printing tasks. This partial action reduces overall temperature retention and evaporation while still providing sufficient circulation to active paths to prevent concentration, avoiding the excessive action of circulating unused paths.
3Quantity of substance
If circulation is stopped to prevent evaporation, then water evaporation is reduced, but ink with increased viscosity cannot be re-circulated
Solution Approach 1:
The system performs preliminary circulation actions before printing to prime the circulation paths and ensure ink is in optimal viscosity state. During printing, circulation continues at controlled rates to prevent excessive evaporation. After printing, preliminary circulation resumes to re-condition the ink before the next printing session, ensuring re-circulation capability is maintained.
Solution Approach 2:
The system uses feedback from print data and circulation monitoring to dynamically adjust circulation rates. When viscosity increases due to evaporation, the feedback mechanism triggers adjusted circulation patterns that gently re-condition the ink without causing excessive evaporation. This feedback loop ensures both evaporation prevention and re-circulation capability are maintained.
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
The solution effectively suppresses ink concentration, ensuring reliable ink discharge and re-circulation by dynamically controlling the circulation of ink based on print data, maintaining optimal viscosity and preventing faulty discharges.
Implementation Method 1
a circulation mechanism that circulates ink in the plurality of circulation paths
Implementation Method 2
when water in the ink evaporates from the nozzle of a print head, the viscosity of the ink at or near the discharge port is increased
Implementation Method 3
temperature retention control and temperature increases due to discharge cause an increase in the temperature of the ink
Data Source
AI summary
A printing apparatus includes an ink discharge head including a plurality of discharge ports that respectively discharge a plurality of types of ink, and a plurality of circulation paths for circulating ink between the plurality of discharge ports and a plurality of liquid chambers that respectively house the plurality of types of ink; a circulation mechanism that circulates ink in the plurality of circulation paths; and a control unit that performs control to determine, based on print data, which path among the plurality of circulation paths that circulation mechanism is to circulate ink in.