JPS5715991A - Ribbon feeder - Google Patents

Abstract

PURPOSE: To prevent the damage on a printing wire, a reduction in printed quality and the like by a method wherein the concentration of an ink on an inked ribbon being passed and the surface condition thereof are detected, and a printing operation is stopped when the detection signals indicates that a defect is generated in the ribbon.

CONSTITUTION: In a ribbon feeder wherein the ink ribbon 1 fitted in a ribbon cassette 2 is fed by driving rollers 4a, 4b in the direction of the arrow and in synchromism with a printing speed at which the paper 6 is printed by a printing head 8 (numeral 7 denotes a platen), a sensor 9 for detecting the concentration of the ink at the fabric part of the ribbon and a fray thereof is provided at a place close to the ribbon 1 being traveled. On the other hand, limit values of the printed density and the fray are preset in a condition memory part 13. the signals from the sensor 9 are fed to a calculating and comparing part 12 through an amplifier 10 and a converting part 11 and are compared to the preset values stored in the memory part 13. When the results of comparison indicate that a defect is generated in the ribbon, the printing operation is stopped through a control command parat 14.

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