Array jet velocity normalization

A system for determining parameter values of voltage divider circuits of an ink jet print head array, the print head array including transducers that produce pressure waves in ink residing in respective chambers to cause ejection of ink drops from respective orifices toward a print medium, the system comprising:

• signal source means for producing an input signal;
• voltage varying means for varying voltage of the input signal;
• plural voltage dividing means receiving the varied input signal at respective inputs of the voltage dividing means for reducing the voltage of the varied input signal by respective amounts, each one of the voltage dividing means including an output that is connected to a respective one of the transducers;
• multiplexing means for controllably connecting the voltage varying means to different respective ones of the inputs of the voltage dividing means;
• and
• memory means for recording values of a parameter of the voltage varying means for later use in altering respective values of a parameter of certain ones of the voltage dividing means.

A method for normalizing actual velocities of ink drops ejected from an orifice of an ink jet print head array such that the actual velocities are substantially equal to a desired velocity, the ink from which the drops are formed residing in a chamber and the print head array including a transducer that, in response to a drive signal developed by a drive circuit that includes a voltage divider circuit, produces pressure waves in the ink and thereby causes the ejection of the ink drops from the orifice toward a print medium at the actual velocities corresponding to the drive signal, the method comprising the steps of:

• establishing a standard that represents a position of the print medium with respect to the orifice;
• electrically coupling an input of the voltage divider circuit to a test driver circuit means including a variable resistive element having a variable resistance value for applying a test input signal to the input of the voltage divider circuit, the print head ejecting test ink drops from the orifice in response to the application of the test input signal;
• determining relative positions of the test ink drops with respect to the standard at predetermined times following the ejections of the test ink drops;
• adjusting the variable resistance value until one of the test drops is aligned with the standard at the predetermined time following the ejection of the one of the test ink drops;
• and
• adding an amount of resistance to the voltage divider circuit equal to the variable resistance value.