THERMAL PRINTER BY MICROPROCESSOR CONTROL

摘要

PURPOSE: To measure two consecutive distances by detecting a distance between consecutive indices on a web in a paper loading sequence and to control the amount of advance of the web in each printing period by using the average value of the distances, at the time when a fresh web is loaded on a printer. CONSTITUTION: A length L of an index mark 37 is measured by feeding a label through the system thereof. The length L is measured by detecting the front and rear ends of the mark 37 and by counting pulses of a pulse motor or a tachometer generated between the detections of the front and rear end. The length L thus measured is divided by two and thereby the center of the mark in relation to the front end can be determined. When it is desired that a web be advanced beyond the center of the mark, a constant K is added advisably to the center distance L/2. The total of L/2 and K is used for measuring the number of pulses by which the web is made to advance inward the index mark after the label is printed.