This paper analyzes the dynamics of a printer mechanism used for graphics printing. The torque induced in the drive motor is idealized as a step function. The friction induced in the mechanism is idealized as viscous damping. The structure of the printer mechanism is idealized to be rigid during operation of the print head drive. The Lagrangian method is used to derive a mathematical model. It is represented in a control system schematic applying feedback. A computer program written in Basic simulates the system under control, in order to predict the outputs, velocity and position, given the input, torque. The computer aided analysis enables the designer to minimize print placement error due to imprecision.