A method of printing on a print medium with a printer which is in communication with a host computer includes the steps of providing the host computer with a print job to be printed by the printer, identifying a data format associated with the print job, determining an operating system stored in the printer, comparing the data format with the printer operating system, downloading an operating system which corresponds to the data format from the host computer to the printer if the printer operating system does not correspond to the data format, transmitting print data associated with the print job from the host computer to the printer, and printing on the print medium with the printer using the print data.

A control system in the form of an all-digital phase-locked loop controls movement of a DC motor. The control system includes a movement detector in the form of an optical encoder to detect movement of a DC motor. A digital phase detector compares output of a feedback signal from the movement detector and a reference signal. The digital phase detector is phase frequency detector that follows a describing function to model non-linear components of the reference signal. A digital loop filter then filters noise from the comparison signal and the filtered signal is amplified to control the DC motor. The phase frequency detector includes a state machine to track a time varying reference signal and selectively output a response to provide for system damping.

A method and system for controlling a stepper motor that may be used in a paper feed rolling arrangement of a printer. The method includes storing step mode selection data in combination with time data in a single table for retrieval and use by a controller.

The invention relates to a method and an apparatus for firing the nozzles on an ink jet print head cartridge that requires a reduced number of data lines between the ink jet print head cartridge and the printer electronics. A group data line provides serial group select data that is stored in a set of group select latches on the ink jet print head cartridge and identifies a particular group of nozzles on the ink jet print head. A primitive data line provides primitive select data that is stored in a set of primitive select latches on the ink jet print head cartridge and identifies a particular nozzle in the selected set of nozzles. A first clock line provides a first clock signal that is used to advance the group select data and the primitive select data into the group select latches and primitive select latches respectively. The group select data and the primitive select data is decoded to produce firing data which is advanced to a set of firing latches in accordance with a second clock signal that is provided on a second clock line. The data in the firing latches is logically ANDed or NANDed with a firing pulse provided on a firing line in order to expel a drop of ink from the selected nozzle or nozzles on the ink jet print head cartridge.