Inkjet Head Drive Voltage Generator Timing Control
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Solution Overview
Problem
Existing inkjet recording apparatuses face complications in control and reduced print speed due to remaining vibration from preceding print cycles, which deteriorate print quality in subsequent cycles.
Innovation Solution
The method involves setting specific relationships between cycle times, drive pulse signal application times, and inactive periods in the inkjet head to minimize the effect of remaining vibration, including Tc = (Td1 + Td2 + ... + TdN) + Te, where Te = (0.5 + m) × Ta, and Trk = n × Ta, with Tr1 > Tr2 > ... > TrN, to ensure efficient ink droplet ejection without extending the inactive period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the drive pulse signal is output with a time delay of a predetermined period from a start timing of the print cycle to prevent excess ink droplets, then satellite droplets are reduced, but print speed is lowered
Solution Approach 1:
The patent applies dynamics by making the inactive period variable rather than fixed. The inactive period is dynamically adjusted based on the number of ink droplets ejected in the previous print cycle. When fewer droplets are ejected, the inactive period is shortened, allowing the next drive pulse to be applied earlier and maintaining higher print speed while still preventing satellite droplets.
Solution Approach 2:
The patent changes the parameter of the inactive period duration based on the ejection history. By setting the inactive period to a value smaller than the pressure propagation time Ta when fewer ink droplets are ejected, the system adapts the timing parameters to match the actual physical state of the pressure chamber, eliminating unnecessary delays while maintaining print quality.
2Manufacturing precision
If auxiliary voltage pulses are added to the drive pulse signal to prevent unnecessary ink droplet ejection, then control precision is improved, but control complexity increases
Solution Approach 1:
The patent extracts and eliminates the unnecessary auxiliary voltage pulse from the drive signal structure. By carefully designing the inactive period to extend through the entire duration needed to prevent satellite droplets, the system achieves the same control precision without requiring additional auxiliary pulses, thereby simplifying the control structure.
Solution Approach 2:
The patent uses periodic action by structuring the drive pulse signals with regularly spaced intervals and using the inactive period as a consistent timing element. This periodic structure allows the system to maintain precise control over droplet ejection while using a simple, repeatable control pattern rather than complex variable adjustments.
3Manufacturing precision
If a long inactive period is set to eliminate remaining vibration effects, then print quality is improved, but print speed is reduced
Solution Approach 1:
The patent applies dynamics by making the inactive period variable rather than fixed. The inactive period is dynamically adjusted based on the number of ink droplets ejected in the previous print cycle. When fewer droplets are ejected, the inactive period is shortened, allowing the next drive pulse to be applied earlier and maintaining higher print speed while still preventing satellite droplets.
Solution Approach 2:
The patent applies partial action by setting the inactive period to exactly the minimum duration needed to prevent satellite droplets and eliminate harmful vibrations, rather than using a uniformly long inactive period for all cases. This allows the system to achieve sufficient vibration damping without the excessive time loss that would occur with a consistently long inactive period.
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 reduces the impact of remaining vibration on print quality without increasing control complexity or reducing print speed, ensuring consistent ink droplet ejection and maintaining high print speed.
Implementation Method 1
a piezoelectric element 15 which provides pressure vibration to the ink in the pressure chamber 11 by deformation of the diaphragm 14 in accordance with a drive pulse signal applied from a drive voltage generator 2
Implementation Method 2
pressure propagation time Ta of a pressure wave that propagates in each of the pressure chambers from the common pressure chamber to the nozzle
Data Source
Figure 1~3
Figure 4~6
Figure 7
AI summary
An inkjet recording apparatus includes actuators (16) provided in an inkjet head (1), and a drive voltage generator (2) that drives each actuator (16). The drive voltage generator (2) is configured to set the cycle time Tc, the drop cycle Td, the number of ink droplets N for a maximum tone, and the inactive period Te in a relationship of Tc = Td × N + Te, set the drop cycle Td and the inactive period Te, by referencing pressure propagation time Ta in relationships of Td = n × Ta (where n = 1, 2, 3, ...) and Te = (0.5 + m) × Ta (where m = 1, 2, 3, ...), and make an output timing of the final drive pulse signal for a dot of a tone other than the maximum tone coincide with an output timing of the final drive pulse signal for the maximum tone.