Methods, apparatus and control systems for droplet deposition apparatus

A control system for a droplet deposition apparatus having at least one nozzle meniscus, the control system being configured to implement a method, the method comprising the steps of:

• (a) receiving a first data block for a first line pixel and a second data block for a second line pixel;
• (b) receiving a data set of forbidden pixel periods that cause harmonic/subharmonic excitation of the meniscus surface and lead to meniscus instability;
• (c) determining a first jitter delay value based on the data set of forbidden pixel periods;
• (d) generating first print data based on the first data block, wherein
• the first print data comprises data defining a first holding period, determined by the first jitter delay value, and one or more drive pulses;
• and
• (e) generating second print data based on the second data block, wherein the second print data comprises data defining one or more drive pulses, the time between each first of the one or more drive pulses defined by the first and second print data determining a first pixel period;
• wherein the first and second print data are for generating first and second actuating element signals for controlling at least one actuating element of the droplet deposition apparatus according to the first and second print data;
• such that each drive pulse causes the actuating element to eject at least one droplet from a respective nozzle of the droplet deposition apparatus;
• and
• the first jitter delay value adjusts the first pixel period to fall outside of the data set of forbidden pixel periods so as to reduce the occurrence of nozzle meniscus instability.

A non-transitory computer-readable medium for reducing nozzle meniscus instability in a droplet deposition apparatus having at least one nozzle meniscus, comprising instructions stored thereon, that when executed cause at least one controller to perform the steps of:

• (a) receiving a first data block for a first line pixel and a second data block for a second line pixel;
• (b) receiving a data set of forbidden pixel periods that cause harmonic/subharmonic excitation of the meniscus surface and lead to meniscus instability;
• (c) determining a first jitter delay value based on the data set of forbidden pixel periods;
• (d) generating first print data based on the first data block, wherein
• the first print data comprises data defining a first holding period, determined by the first jitter delay value, and one or more drive pulses;
• and
• (e) generating second print data based on the second data block, wherein
• the second print data comprises data defining one or more drive pulses, the time between each first of the one or more drive pulses defined by the first and second print data determining a first pixel period;
• wherein the first and second print data are for generating first and second actuating element signals for controlling at least one actuating element of the droplet deposition apparatus according to the first and second print data;
• such that each drive pulse causes the actuating element to eject at least one droplet from a respective nozzle of the droplet deposition apparatus;
• and
• the first jitter delay value adjusts the first pixel period to fall outside of the data set of forbidden pixel periods so as to reduce the occurrence of nozzle meniscus instability.