Ink Jet Drive Signal Equalizes Liquid Column Velocity
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Solution Overview
Problem
The ink jet recording apparatus faces image quality degradation due to the formation of satellites when droplets are discharged at higher velocities, leading to poor image quality.
Innovation Solution
The apparatus employs a drive signal with multiple discharge pulses that ensure the velocities of liquid columns are equalized after a predetermined time, using a combination of expansion and contraction pulses to manage ink discharge and reduce satellite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple droplets are discharged to one pixel with increasing velocity for shading, then image density and shading are improved, but satellite formation increases and image quality degrades
Solution Approach 1:
The patent applies dynamics by making the discharge velocity of liquid columns equal after a predetermined time rather than immediately. This is achieved by adjusting the drive signal waveform so that the velocity of the tip of each liquid column becomes substantially equal after a specific time period from discharge start, allowing controlled droplet formation without excessive satellite generation while maintaining shading capability
Solution Approach 2:
The patent changes the parameter of discharge velocity timing by equalizing the velocities of liquid columns after a predetermined time. The drive signal is designed to make the velocity of the tip of each liquid column substantially equal after a specific time period, which controls the droplet formation process and reduces satellite formation while maintaining multi-drop shading functionality
2Stability of the object's composition
If droplet discharge velocity is increased for multi-drop shading, then droplet combination capability is improved, but droplet separation and satellite formation occur
Solution Approach 1:
The patent applies dynamics by making the discharge velocity of liquid columns equal after a predetermined time rather than immediately. This is achieved by adjusting the drive signal waveform so that the velocity of the tip of each liquid column becomes substantially equal after a specific time period from discharge start, allowing controlled droplet formation without excessive satellite generation while maintaining shading capability
Solution Approach 2:
The patent uses periodic action through multiple discharge pulses applied to the piezoelectric element. The drive signal includes multiple pulses that discharge droplets at different timings, with the velocity of each liquid column being equalized after a predetermined time, enabling controlled periodic droplet ejection for multi-drop shading
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 satellite formation and improves image quality by maintaining consistent droplet velocities, ensuring better ink combination and reduced droplet separation.
Implementation Method 1
a piezoelectric element in the ink jet head, and a drive circuit that generates a drive signal for discharging multiple droplets to one pixel for combining the multiple droplets together, and applies the drive signal to the piezoelectric element
Data Source
AI summary
There is provided an ink jet recording apparatus including an ink jet head and a drive circuit. The ink jet head forms an image on a recording medium in response to a drive signal applied to multiple piezoelectric elements. The drive signal causes multiple pressure chambers corresponding to the multiple piezoelectric elements to expand or to contract in volume and causes ink in the multiple pressure chambers to be discharged from multiple nozzles. The drive circuit generates a drive signal for discharging multiple liquid droplets to one pixel for combining the multiple liquid droplets together and applies the drive signal to each of the multiple piezoelectric elements of the ink jet head. The drive signal includes multiple discharge pulses which make velocities of tips of respective liquid columns substantially same after a predetermined time from starting of ink discharge from the nozzles.