An Improvement in the Art of Chain Printing 4006

John Savard

PITA is correct.

-First you hook up the oscilloscope to the appropriate test points. -Then start the designated test pattern -Then adjust the tiny hex screw way in the back or this noisy machine with lots of moving parts and exposed voltage sources for the correct timing pattern.

( Finally fiddle it some more until the printed characters look right )

Timing accuracy is the big issue with these machines. You have to move beg, heavy( in a relative sense ) parts around, determine their positions accurately, push them at just the right time to get your pre-formed pattern onto the paper. This has to be consistent in "real world" conditions of varying input power, temperature, humidity, paper quality and thickness. What happens when an adhesive label gets stuck in the paper path? ( they are allways doing that! ) What if the customer wants more fonts or characters?

The closest that I have seen to a perfect line printer first appeared in Printronix, then later Citoh and Genicom,, and maybe others I have not seen.

They use a single row of dots( the hammers ) spaced across the entire paper width. The hammerbank shuttles left to right to form the vertical component of the character matrix. Paper movement creates the vertical component. Software can put any dot in any position on the page, much like laser printers form a printout.

Put all of the precision in a few easily interchanged parts and have a consistant look all over the page. At least that is how they are when new.

-- you must be 21 to enter I may be demented but I'm not crazy! * SPAyM trap: there is no X in my address *