Patent ID: 7467840
Filing Date: 2008-12-23
Classification: B41J

Abstract:
1. A method for controlling volume of droplets of printing fluid ( 18 ) emitted from a print head ( 1 , 2 ) during a printing process; said print head ( 1 , 2 ) having: at least one pump ( 10 , 20 ) having an inlet for taking in the printing fluid ( 18 ), a pump chamber ( 11 ) for containing the printing fluid ( 18 ) and an outlet for letting out printing fluid ( 18 ); and an actuator ( 16 ) for generating actuation pulses acting on the printing fluid ( 18 ) in the pump ( 10 , 20 ); said method comprising the following steps: determining a first characteristic frequency of the pump ( actuating the actuator ( determining a second characteristic frequency of the pump ( comparing the second characteristic frequency to the first characteristic frequency; and determining the value of the actuation pulse which needs to be generated by the actuator (