MX-M950, MX-MM1100 (serv.man15). Details of Each Section - C DSPF Section - Sharp Copying Equipment Service Manual (repair manual). Page 6

MX-M1100  DSPF SECTION  C – 6

The sensor is composed of ultrasonic generator part and ultrasonic
detector. Doublesheet feeding is detected by the change in sound
frequency.
Operation when sheets of paper are normally fed one by one
Some of the ultrasound is reflected by the paper, but the ultrasound
reaches the sensor more than the specified level.
The sensor analog output level at that time is 300mV or more, and
digital output level is "L."
Operation when double feed occurs
Most of ultrasound is reflected when double feed occurs, because
the stiffness of paper is high.  As a result, the ultrasound which
reaches the sensor is weak, and less than the specified level.
At that time, the sensor analog output level is 300mV or less, the
digital output level is "H."

1)

Remove the upper cabinet left of the machine.

2)

Remove the screw (a), the clamp (b), and the earth wire (c).
Open the edge saddle (d), and disconnect the connector (e).

3)

Remove the screw (a), and remove the cover (b). Remove the
screw (c) and the snap band (d).

4)

Loosen the screw (a), and lower the fixing plate (b).

5)

Remove the screw (a) and slide the DSPF unit (b) to the rear
side to remove.

DSPF unit

A

Front cabinet

C - 7/ a

B

Rear cabinet

B

A

a

b

c

d

e

e

a

c

b

d

a

a

b

b

a