Continuous plotter

Apparatus for plotting information comprising:

• a base structure;
• means for mounting a supply reel of recording medium on said base structure;
• means for mounting a takeup reel on said base structure;
• an exposure surface positioned on said base structure so that recording medium passing from said supply reel to said takeup reel will lie substantially flat on said exposure surface;
• means adapted to advance said recording medium across said exposure surface;
• a carriage movably mounted on said base structure and adapted to move back and forth across said exposure surface;
• a means carried by said carriage and adapted to receive information from an information source and to project said information onto said exposure surface;
• and
• means to drive said carriage back and forth across said exposure surface at a controlled rate, said drive means comprising:
• a lead screw extending along the length of said exposure surface;
• means on said carriage in cooperation with said lead screw;
• and
• motor means coupled to said lead screw for rotating said lead screw to move said carriage, said motor means comprising:
• a stepping motor which rotates an exact increment each time said motor receives a pulse of a frequency signal;
• and
• control circuitry means for supplying a precise frequency signal of desired value to said stepping motor for driving said motor at a desired speed, said control circuitry means including:
• means for gradually increasing said precise frequency signal from 0 to a maximum value upon receiving a start signal to accelerate said motor to said desired speed;
• and
• means for gradually decreasing said precise frequency signal from said maximum value to 0 upon receiving a stop signal to decelerate said motor from said desired speed to a stopped position.