Inkjet Recording Apparatus Selective Nozzle Drive Waveform Control
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Solution Overview
Problem
Inkjet recording apparatuses face inefficiencies in preventing ink dryout and clogging due to increased viscosity in nozzles, leading to improper ink discharge and waste, especially in line head recording methods where some nozzles remain unused, resulting in unnecessary preparatory discharge of ink.
Innovation Solution
The apparatus employs a controller and head driver system with drive pulse generators and selectors to manage drive waveforms for piezoelectric elements, allowing for targeted ink discharge and meniscus swinging in nozzles, minimizing ink wastage by performing preparatory discharge only when necessary and dispersing it in the sub-scanning direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If meniscus swinging is performed to prevent nozzle clogging, then nozzle reliability is improved, but ink viscosity increases due to stirring and evaporation, worsening ink dischargeability
Solution Approach 1:
The patent changes the driving parameters by selecting different drive waveforms (first through fourth waveforms) based on nozzle usage status. For nozzles not discharging ink, meniscus swinging with specific drive waveforms (third or fourth) is applied to prevent clogging without excessive stirring. For nozzles discharging ink, different drive waveforms (first or second) are used to maintain discharge performance despite viscosity changes.
Solution Approach 2:
The patent applies different drive waveforms to different nozzles based on their individual discharge status. Nozzles that have not discharged ink receive meniscus swinging treatment with specific waveforms, while nozzles that have discharged ink receive different treatment. This localized approach prevents unnecessary viscosity increase in nozzles that don't require it.
2Reliability
If preparatory discharge is performed to discharge high-viscosity ink, then ink dischargeability is improved, but ink waste increases
Solution Approach 1:
The patent applies preparatory discharge selectively only to nozzles that have not discharged ink, identified by the drive waveform selector. Nozzles that have already discharged ink skip the preparatory discharge step. This localized application eliminates unnecessary ink waste while maintaining discharge reliability for nozzles that need it.
Solution Approach 2:
Instead of performing preparatory discharge on all nozzles, the patent applies it partially only to nozzles that require it (those not discharging ink). This partial action approach reduces ink waste significantly while still preventing clogging in the nozzles that need prevention.
3Reliability
If conventional recovery process with purging and wiping is used, then nozzle clogging is prevented, but large amounts of ink are wasted and process complexity increases
Solution Approach 1:
The patent extracts and eliminates the wiping step from the conventional purging-and-wiping recovery process. Instead of forcing ink out and then wiping it off, the system uses selective preparatory discharge that only activates nozzles as needed, eliminating the need for wiping and reducing ink waste associated with the wiping process.
Solution Approach 2:
The patent performs preparatory discharge in advance for nozzles that will be used in subsequent printing. By identifying nozzles that haven't discharged ink and performing selective preparatory discharge on them, the system prevents clogging before printing begins, eliminating the need for post-printing recovery operations.
4Reliability
If meniscus swinging is applied to all nozzles, then clogging prevention is improved, but productivity decreases due to unnecessary operations
Solution Approach 1:
The patent applies meniscus swinging selectively only to nozzles that have not discharged ink, as identified by the drive waveform selector. Nozzles that have already discharged ink skip the meniscus swinging treatment. This selective application maintains discharge stability for nozzles that need it while improving productivity by eliminating unnecessary operations on nozzles that don't need treatment.
Solution Approach 2:
Instead of applying meniscus swinging to all nozzles, the patent applies it partially only to the subset of nozzles that require it. This partial action approach maintains reliability for critical nozzles while improving overall printing efficiency by reducing the number of unnecessary meniscus swinging operations.
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 stabilizes ink discharge, reduces waste, and prevents clogging by ensuring only necessary ink is discharged, maintaining image quality and nozzle functionality even after prolonged disuse.
Implementation Method 1
the force produced by a piezoelectric element is transmitted, as a pressure, to ink inside a pressurizing chamber so that the pressure makes the ink meniscus inside a nozzle swing for generating ink droplets
Implementation Method 2
the ink meniscus inside a nozzle is oscillated in such a degree as not to discharge ink, with the aim of preventing nozzle clogging
Implementation Method 3
moisture keeps evaporating from the ink inside it, and the ink comes to have increased viscosity
Data Source
AI summary
In an inkjet recording apparatus, when one set of image data is divided in the sub scanning direction into A bands, and nozzles are divided in the main scanning direction into groups each comprising A nozzles, a selector associates, within each of the group, the nozzles in the first to Ath columns with the first to Ath bands with no overlap, and, for a nozzle that is to discharge ink for one pixel or less within one set of image data, makes the nozzle perform preparatory discharge in the band associated with the nozzle by selecting, out of different ink discharge drive waveforms, a first drive waveform (1) corresponding to the minimum gradation.