Printhead Wiping Timing Control to Prevent Ink Color Mixture
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Solution Overview
Problem
Existing inkjet printing technologies face issues of color mixture due to ink mist entering ejection ports during wiping operations, which can lead to decreased throughput and ink viscosity increase, especially when wiping is performed during or after ink circulation.
Innovation Solution
A control unit manages the wiping operation of the cleaning member to ensure it is performed after the ink circulation pump is stopped, with the timing based on the elapsed time since pump shutdown to prevent color mixture, and a winding operation is conducted if necessary to maintain wiping accuracy and prevent ink deep penetration into ejection ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wiping is performed during ink circulation, then throughput is improved, but color mixture occurs due to ink mist entering ejection ports
Solution Approach 1:
The circulation pump is stopped before the wiping operation begins, preventing ink mist from entering the ejection ports during cleaning. This preliminary action eliminates the harmful effect of color mixture while maintaining efficient throughput by minimizing the interruption to the printing process.
2Object-generated harmful factors
If wiping is performed after the circulation pump is stopped, then color mixture is suppressed, but throughput drops
Solution Approach 1:
The system dynamically adjusts the timing of the wiping operation based on the circulation pump status. By coordinating the wiping operation to occur immediately after the circulation pump stops, the system achieves both color mixture suppression and maintained throughput, resolving the contradiction between cleaning effectiveness and productivity.
3Device complexity
If the cleaning member is not wound during wiping, then device complexity is reduced, but wiping accuracy decreases leading to ink deep penetration
Solution Approach 1:
The cleaning member is pre-wound to expose a fresh, clean surface before the wiping operation begins. This preliminary winding action ensures that the cleaning member makes optimal contact with the ejection ports, preventing ink from penetrating deep into the print head while maintaining a relatively simple device structure.
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 approach effectively suppresses color mixture and maintains throughput by ensuring the wiping operation is performed at optimal times, reducing the need for additional cleaning member consumption while ensuring efficient ink removal from ejection ports.
Implementation Method 1
a circulation pump configured to circulate the ink in a circulation channel including the first channel, the pressure chamber, and a second channel
Implementation Method 2
a wiping unit configured with a cleaning member that can wipe an ejection port surface of an ejection port
Data Source
AI summary
A printing apparatus including a print head ejecting ink, flowing from a first channel into a pressure chamber, from a nozzle, by driving an ejection energy generating element in the pressure chamber, a circulation pump circulates the ink in a circulation channel including the first channel, the pressure chamber, and a second channel that flows the ink from inside the pressure chamber to the outside, a wiping unit with a cleaning member that wipes an ejection port surface of an ejection port and a winding member that winds the cleaning member, and a control unit controls a cleaning operation in which the wiping unit wipes the ejection port surface. When the cleaning operation is performed after the circulation pump is stopped, the cleaning operation is changed based on an elapsed time from the time the circulation pump stopped driving, and the cleaning operation is controlled based on the elapsed time.