Oki PACEMARK 4410 Maintenance Manual

Also see for Microline 4410: User guide

Contents

40496501TH Rev.1 322.1.14 Alarm circuits(1) Driver circuit abnormality detection alarm.This protective circuite prevents secondary troubles by stopping the power supply upondetection of an abnormality in the print head, SP motor driver circuit or other motor drivercircuits.This circuit monitors the driving time by means of the signals (DT1COM1, SPV, LF COM, AG-MCOM, RBN-MCOM, TR-MCOM, BEIL-MCOM and RENCOM) connected to the overdrivesignals for each driver circuit. If any driver circuit driving time exceeds the specified time, thePOWOFF-P signal is output to switch off the power supply to stop all DC voltage outputs.(2) Head high temperature alarm circuitThe thermistor built in the head monitors the head temperature for head coil protection.If high duty printing continues for a long time, the head temperature rises. If it reaches acertain level (approx. 148 °C and 158°C), head high temperature alarm 1 is detected to startone-way printing with a 40 ms interval after each line. When head temperature alarm 2 isdetected to start one-way and two-pass printing with a 1.2 sec. interval after each line for thehead temperature to fall. When the temperature falls to below the detection temperature,normal printing operation restarts.As the head temperature rises, the resistance of the thermistor decreases and the potentialof the input to the comparator in the head thermistor alarm circuit rises, when the potentialgoes above the alarm 1 specific level, MPU goes into alarm 1 procedure, simultaneously MPUcontinues to check if the potential goes above alarm 2 specific level. When going below alarm2 level, MPU goes into alarm 2 procedure.(3) Paper end detection circuitFive sensors (front tractor paper end sensor, rear tractor paper end sensor, sheet jam sensor,sheet top sensor and sheet width sensor) are provided for different paper set routes to monitorpaper end. When paper runs out, the corresponding sensor is turned off to input theFTRPESW-P, RTRPESW-P, SHEETJAM-P, SHEETTOP-P, SHEETWITH-N signal to thesub LSI (IC17), and is read by the MPU. The MPU stops the printing operation, informs thehost of the paper end and jam, and lights the alarm lamp.(4) Cover open alarm circuitWhen the front access cover is PUSH opened, the COVEROPN1SW-P signal is input to themain LSI and the NHDC LSI from the cover open microswitch, and an invalid signal is inputto MPU. The MPU stops the printing operation as soon as possible, informs the host thatreceiving is impossible, and lights the alarm lamp.When the front access cover is opened and, the interlock switch cuts the SP motor drivecurrent and makes the SP motor stop.(5) Fan alarm circuitFor each of the five fans, the FANALM-P signal is provided to detect fan rotation/stop. Thesignal is at Low level when the fan rotates, while it becomes High when it stops. The MPUmonitors this signal level. When the High level is kept for one minute or longer, the MPU stopsthe printing operation, informs the host of the fan alarm, and lights the alarm lamp.