Ink Jet Printer Nozzle Cleaning via Combined Pre-Fire Pulses
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Solution Overview
Problem
Ink jet printers face challenges in maintaining print quality due to nozzle clogging and ink drying issues, which lead to increased energy consumption and reduced print head lifespan, especially when spitting pulses are applied regularly without considering the image being printed.
Innovation Solution
The implementation of combined pulse sequences, including pre-fire pulses with amplitudes below the threshold for droplet ejection, significantly improves cleaning efficiency, allowing for longer intervals between spitting operations and reduced energy consumption by using fewer pulses, thus enhancing print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spitting pulses are applied regularly to prevent nozzle clogging, then nozzle reliability is improved, but print quality deteriorates due to unwanted droplets on the print medium
Solution Approach 1:
The patent applies pre-fire pulses before spitting pulses to preliminarily agitate the ink in the nozzle, reducing ink adhesion to nozzle walls and enhancing the cleaning effect of subsequent spitting pulses, thereby improving nozzle reliability while reducing spitting frequency
Solution Approach 2:
The patent replaces regular spitting pulses with periodic combined pulse sequences that include pre-fire pulses followed by spitting pulses, optimizing the timing and composition of pulse sequences to maintain nozzle reliability while minimizing unwanted droplet deposition on the print medium
2Reliability
If multiple pre-fire pulses are applied to each nozzle before printing to prevent ink drying, then nozzle reliability is improved, but energy consumption increases and actuator lifespan decreases
Solution Approach 1:
The patent applies a limited number of pre-fire pulses (not excessive numbers) before each spitting pulse, providing just sufficient agitation to reduce ink adhesion without causing over-vibration that would waste energy and stress the actuator
Solution Approach 2:
The patent merges pre-fire pulses and spitting pulses into combined pulse sequences, where pre-fire pulses prepare the ink for subsequent spitting, thereby reducing the total number of separate operations needed and lowering overall energy consumption
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 extends the time between spitting operations, reduces the number of spitting pulses per page, and maintains print quality while minimizing energy use and print head wear, allowing for more efficient and longer-lasting printer operation.
Implementation Method 1
actuators respectively associated with the nozzles and arranged to create pressure waves in the ink to be discharged from the respective nozzles
Implementation Method 2
the actuators are exited by so-called pre-fire pulses the amplitude of which is kept so small that the meniscus of the liquid ink is only vibrated in the nozzle orifice but no droplets are formed and ejected. The vibrations induced in the liquid ink have the purpose to remove or dissolve the dry ink that would otherwise adhere to the walls of the nozzle orifices.
Data Source
AI summary
An ink jet printer having a number of ink discharge nozzles, a number of actuators respectively associated with the nozzles and arranged to create pressure waves in the ink to be discharged from the respective nozzles, and a controller arranged to apply drive signals (38) to the actuators in accordance with print instructions for an image to be printed, wherein the drive signals (38) comprise print pulses (44) causing ink droplets to be ejected from the nozzles at timings when the respective nozzle faces an image part of a print medium, and spitting pulses (42) causing ink droplets to be ejected from the nozzles at timings when the respective nozzle faces a non-image part of the print medium, and the drive signals (38) further comprise pre-fire pulses (40) which have an amplitude below a threshold at which ink droplets are ejected, and the controller is arranged to apply the spitting pulses (42) in the form of combined pulse sequences that each comprise a number of pre-fire pulses (40) preceding the spitting pulse (42).