Abstract: Apparatus and methods for field programmable print control of an ink jet printer allow the timing and control parameters of the ink jet printer to be altered. This allows a user to replace the printhead with a higher resolution printhead. The ink jet printer has a timer processing unit that contains the timing and control parameters needed by the ink jet control circuit to generate the printhead control signals. The timer processing unit is connected to a timer interface, which may be a programmable logic interface. The timer interface receives high level timing and control signals from a data source outside the ink jet printer controller and translates the timing and control signals into timing and control data for the timer processing unit. The data source may be a computer connected to the ink jet printer. Alternatively, the data may be stored in a memory of a replacement printhead and downloaded to the controller upon replacing a current printhead with the replacement printhead.

Abstract: A programmable encoder having an addressable display device to display an encoder pattern of fiducial marks. The programmable encoder can be programmed to display an encoder pattern on a liquid crystal display. A sensor senses the marks on the pattern and generates sensor signals indicative of the sensed pattern. A controller connected to the sensor receives the sensor signals and outputs control signals which control the movement of a machine, such as an ink jet printer. The programmable encoder can be programmed to display any number of patterns on the addressable display device, and consequently, is highly adaptable to any number of applications requiring position, speed, or acceleration control.