Registration means for printers and the like

Apparatus for electronically controlling the printing of N dot patterns and the like on a paper document to assure proper registration of the dot patterns comprising:

• a movable carriage;
• a print head assembly mounted upon said carriage and including print control means for producing dot patterns;
• means for moving the carriage across the paper document between the margins of said paper document at a substantially constant speed during printing;
• a light source and a light sensing element arranged in spaced fashion and mounted upon said carriage assembly;
• a flag mounted near one of said margins and movable between said light source and said light sensing element to selectively interrupt light from said source from reaching said light sensitive element;
• gated oscillator means;
• means normally disabling said gated oscillator means and responsive to activation of said carriage moving means and said light sensitive element for enabling said oscillator means.
• said oscillator means comprising R-C timing means for generating print control pulses at a constant frequency;
• means coupling the output of said oscillator means to said print control means for enabling said print control means at uniform spaced intervals determined by said print control pulses whereby the number of pulses generated causes the printing of N patterns at equi-spaced intervals along a line when said carriage is moving at said constant speed.

Apparatus for controlling registration of a line of dot patterns to be printed on a paper document in a dot matrix impact printer comprising:

• printing means movable across the document;
• normally disabled gated oscillator means;
• means adjacent one margin of the document and responsive to movement of the printing means towards the opposite margin for initiating the running of said oscillator means;
• the output of said oscillating means being coupled to said printing means for enabling printing at equi-spaced intervals along a line of print;
• means for storing character codes representative of the line of characters to be printed;
• means responsive to the oscillator means for selectively advancing character codes to character generator means;
• said advancing means including counter means being incremented as each character code is advanced;
• means for disabling said gated oscillator means responsive to a predetermined count in said counter means and including further means responsive thereto for returning the printing means to said one margin.