| 摘要 |
PURPOSE:To enable a printed condition to be detected immediately after printing, by detecting a misprint generated by a trouble or malfunction of a printing mechanism part by a method wherein light is cast on a printed character pattern, the light reflected from the pattern is detected, the quantity of light is converted into an electrical signal, and the signal is compared with character pattern data. CONSTITUTION:A print-recognizing part 60 comprises a set of light-emitting parts and light-receiving parts disposed at positions corresponding to one row, and functions to quantize a column of printing patterns into data consisting of seven '1' or '0' bits. The light-emitting part constantly emits light, the light reflected from the medium is inputted to a photo-diode by an optical fiber cable, is simplified by an amplifier, and the result of comparison of the amplified signal with a reference voltage by a comparator is sent to a data buffer 50 in a printing-controlling circuit through a buffer. The reference voltage is a voltage set by the voltage dividing ratio of R1 and R2, and is so adjusted that the output of the comparator for the presence of a print is '1' while the output for the absence of any print is '0'. |
