SHARP EL1801P
Manual de Servicio

The character position detecting signal (CP) is to be made by the user from the leading edges of the set signal and reset signal. This CP corresponds to the character on the character belt. The standard signal (SD) is a signal output once to the 75CP pulse, and the signal to be made by the user utilizing the leading edge of the second CP from the leading edge of this signal is the standard position signal (SP). The reason why CP and SP are made using the raw signals output from the detector is that the effect of chattering is taken into consideration. The following will explain the basic operation.

counted. 9) The motor driving signal is turned OFF after 19CP counting after the paper feeding is started. In case SP is not found within 19CP after the paper feeding is started, it is turned OFF after SP is detected.
Motor driving signal(MT) Standard pisition detection signal(SP) Character position detection signal(CP) Electromagnetic clutch signal(TM) Carry gear operation

0

89 t0

16 17

22 23 24 25 27 28 19CP(mim) T3 T4

0

3-4. Operation Sequence
The basic operation is explained

Paper reeding operation Rack operation Hammer operation Carry operation

(1) Initialization
In order to make sure that the hammer holder is at its home position, i.e. the first column, print the space after power is turned on, and after the carry / return, do one-line paper feeding and set the hammer holder at its home position. This completes the initialization.
Motor driving signal(MT) Standard pisition detection signal(SP) Character position detection signal(CP) Electromagnetic clutch signal(TM) Carry gear operation Paper reeding operation Rack operation Hammer operation Carry operation

Printing pattern through the adove operation
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0

89

21

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Fig. 5 Time Chart for 1-Line Printing (0. |___| * printing)

(3) Continuous printing operation
1) After the 1-line printing operation in (2), the motor driving signal (MT) is not turned OFF and the operations 2) through 8) are continuously done for the necessary number of columns while the motor is run. 2) After the most significant digit of the last line is printed, the operations 7), 8) and 9) in (2) are done and the motor is stopped.

(4) Paper feeding operation
Fig. 4 Time Chart at Initialization For the paper feeding operation, 1-line printing of space may be done in the same way as for the printing operation sequence.

(2) 1-line printing operation
1) The printing operation is started by setting the motor driving signal (MT) ON. 2) Prior to 1-line printing, detect the standard position signal (SP) once and make the time from the leading edge of the character position detection signal CP8 to the leading edge of CP9 to and make it standard pulse width. (This to setting must be done at the initialization and prior to the 1-line printing. to is utilized for error detection.) 3) The character belt rotates until the desired CP pulse is detected. 4) If the desired CP pulse is detected, power is supplied to the electromagnetic clutch unit, the character belt is stopped, and printing operation / carry operation are done. In the meantime, the power to the electromagnetic unit is cut off. (For the detail, see 1.3.2.Printing / Carry Mechanism.) 5) After completion of the printing / carry operation, the character belt rotates again. 6) The operations 3) through 5) are repeated and 1-line printing is completed. 7) After the most significant digit printing, the electromagnetic clutchsignal TM becomes OFF, and then between T3 and T4, paper feeding / column return operation is done by turning the electromagnetic clutch ON again. T3 = 80 to 200 m sec T4 = (2.0 ~ 2.4) x Tcp 8) After paper feeding is started, it is completed when about 19CP is

3-5. Troubleshooting dislocated print belt
Install the character belt on the drive pulley and driven pulley. When installing the character belt, the following points must be considered. 1) If the driven pulley is removed and mismatched with the CC cam, it should be aligned as follows.

CC cam Boss of frame Hole Frame hole (Driven hole inserting part) Driven pulley

2) The character belt should be positioned as follows. Manually turn the motor to the position where the SD pulse appears.