Cutter Motor Driver Circuit - Brother PT-2300 Service Manual

3.2.7

Cutter Motor Driver Circuit

Fig. 3.2-10 shows a driver circuit of the DC motor which cuts tape after a sequence of printing.
The CPU (U11) activates the transistor array (U2: BA6285) through P31 (pin 61) and P32 (pin 62)
to drive the cutter motor.
Circuit operation
The CPU drives the cutter motor in the following sequence:
The cutter stays in the home position when it is not in operation (The cutter sensor input level is
Low).
If the CPU issues a tape cutting command, this drive circuit rotates the DC motor clockwise for
cutting the tape. The moment the movable blade of the cutter starts and goes out of the home
position, the cutter sensor level goes High. When this sensor level goes Low again, the CPU
recognizes that the movable blade has returned to the home position after cutting the tape and
then applies brake to the DC motor. If the sensor level remains Low for 100 ms when the brake is
applied, the CPU judges that the movable blade stops in the home position and stops the normal
motor drive sequence.
If the movable blade sticks in the home position for 300 ms or does not return to the home position
for 1000 ms after the DC motor starts rotating clockwise, the CPU regards it as an error and starts
error processing (and shows the
If the movable blade lies out of the home position due to abnormal end of operation, you need to
turn the power off and on with the "On/Off (
counterclockwise to return the movable blade to the home position (initializing the cutter).
message on the LCD).
CUTTER
ERROR!
)" key. Then the CPU rotates the cutter motor
Fig. 3.2-10 Cutter Motor Driver Circuit
III-10