The line printer ran at 600 lines per minute, using a continuously rotating print drum technology, with letters, figures and punctuation marks distributed around the drum at each column. 132 solenoid-operated flat-faced print hammers comprised a print line, with ten characters to the inch. When a desired character arrived at the printing position, as indicated by timing marks on the end of the drum, a thyratron would fire and energize a print column solenoid, propelling its hammer to the back face of the printing paper. The paper would be bounced against a wide inked ribbon and against the drum, printing the desired character. The hammer would then rebound with a spring to await the next thyratron firing and the process would repeat on the next line down the sheet. Drum printers, when not adjusted properly, or due to component wear would mis-register the character vertically.