Thermal-ink-jet print system with drop detector for drive pulse optimization

A system comprising:

• a thermal ink jet print head with a print drop generator set having at least one print generator each print drop generator of said set having pulse input means for receiving an electrical pulse and drop output means through which ink can be propelled in response to said electrical pulse;
• pulse generator means for generating electrical pulses, said pulse generator having pulse output means coupled to the pulse input of each print drop generator of said set, said pulse generator means having trigger input means for receiving trigger signals for triggering pulse generation and at least one pulse parameter input for receiving pulse parameter signals for determining at least one energy-related pulse parameter of a pulse generated by said pulse generator means;
• pulse controller means for transmitting trigger signals and pulse parameter signals to said pulse generator means, said pulse controller means being coupled to said trigger input means and said pulse parameter input means of said pulse generator means, said pulse controller means having data input means for receiving data signals to be converted by said pulse controller means into a series of trigger signals and program input means for receiving and storing pulse parameter values;
• drop monitor means for measuring a momentum-related drop parameter for drops propelled from said print drop generators set, said drop monitor means having monitor output means for transmitting momentumrelated measurements;
• test generator means for characterizing each print drop generator of said set as a function of said momentum-related drop parameter versus said energy-related pulse parameter, said test generator means having test generator input means coupled to said monitor output means for receiving said momentum-related measurements, said test generator means having test generator output means coupled to said program input means of said pulse controller means for transmitting test generator outputs to vary generated pulses according to a predetermined energy-related parameter, said test generator means having test data output means for transmitting characterizing information as to said momentum-related measurements as a function of said test generator outputs;
• and
• algorithm means for determining an optimal value for said energyrelated related pulse parameter for each channel of said set, said algorithm means being coupled to said data output means of said test generator means for receiving said characterizing information therefrom, said algorithm means being coupled to said program input means of said pulse controller means for transmitting pulse parameter values thereto.

A system comprising:

• transducer means for converting pulses characterizable by respective pulse energies and corresponding energy-related pulse parameter values into output events characterizable by respective output energies and a corresponding energy-related output parameter values,
• said transducer means being characterizable by an energy function of said output energies versus said pulse energies, said energy function being monotonically increasing over a predetermined pulse energy range, said energy function including an infection point within said predetermined pulse energy range,
• said transducer means being characterizable by a parameter function of said output parameter values versus said pulse parameter values;
• said transducer means having a transducer input for receiving said pulses and a transducer output for outputting said output events;
• pulse generator means for generating said pulses, said pulse generator having and output coupled to said transducer means and an input for receiving control signals;
• pulse control means for controlling the pulse parameter value for each of said pulses, said pulses control means having a control output coupled to the control input of said pulse generator means;
• monitor means for detecting output events and measuring said output parameter values to each detected output event, said monitor means having a detector coupled to said transducer output for receiving output events output thereby, said monitor means having a monitor output for transmitting said output parameter values;
• test generator means for characterizing said parameter function at a number of different pulse parameter values to provide parameter function data, said test generator means being coupled to said pulse control means for selecting different pulse parameter values to characterize pulses generated by said pulse generator means, said test generator means being coupled to said monitor output so that the output parameter value measured for a given output event is identifiable with the pulse converted into the given output event so that pulse parameter values can be related to respective output parameter values;
• and
• algorithm means for determining an operating value for said pulse parameter by applying an algorithm to said parameter function data, said algorithm being selected to yield an operating value within a tolerance range of pulse parameter values corresponding to a pulse energy range lying above said inflection point.

A system comprising:

• a transducer set including at least one transducer means for converting pulses characterizable by respective pulse energies and corresponding energy-related pulse parameter values into output events characterizable by respective output energies and corresponding momentumrelated output parameter values,
• each transducer means of said transducer set being characterizable by an energy function of said output energies versus said pulse energies, said energy function being monotonically increasing over a predetermined pulse energy range, said energy function including an inflection point within said predetermined pulse energy range,
• each transducer means of said set being characterizable by a parameter function of said output parameter values versus said pulse parameter values;
• each transducer means of said set having a transducer input for receiving said pulses and a transducer output for outputting said output events;
• pulse generator means for generating said pulses, said pulse generator having an output coupled to the transducer input of each transducer means of said set and an input for receiving control signals;
• pulse control means for controlling the pulse parameter value for each of said pulses, said pulse control means having a control output coupled to the control input of said pulse generator means;
• monitor means for detecting output events and measuring said output parameter values to each detector output event, said monitor means having a detector coupled to the transducer output of each transducer means of said set for receiving output events output thereby, said monitor means having a monitor output for transmitting said output parameter values;
• test generator means for characterizing the parameter function of each transducer means of said set at a number of different pulse parameter values to provide parameter function data, said test generator means being coupled to said pulse control means for selecting different pulse parameter values to characterize pulses generated by said pulse generator means, said test generator means being coupled to said monitor output so that the output parameter value measured for a given output event is identifiable with the pulse converted into the given output event so that pulse parameter values can be related to respective output parameter values;
• and
• algorithm means for determining for each transducer means of said set an operating value for said pulse parameter by applying an algorithm to said parameter function data, said algorithm being selected to yield an operating value within a tolerance range of pulse parameter values corresponding to a pulse energy range lying above said inflection point.

A method for controlling the energy to a thermal ink jet drop generator having an input for receiving energy pulses and an output for ejecting ink drops, said drop generator being characterized by a transfer function of drop speed versus pulse energy, said transfer function having an inflection point, said method comprising:

• providing a drop detector for providing drop detection data characterizing drops ejected by said drop generator;
• providing to said drop generator a series of energy pulses each of said pulses being characterizable by a value of an energy-related parameter, said series being characterized by a range of values of said energy-related parameter;
• generating test results by mapping drop detection data to pulse data, said pulse data including, for each drop detection, the value of the energyrelated pulse parameter of the pulse causing ejection of that drop;
• and
• calculating an operating value for said energy-related pulse parameter from said test results according to an algorithm selected so that said operating value is within a predetermined range above said inflection point of said transfer function for said drop generator.