MX-M950, MX-MM1100 (serv.man15). Details of Each Section - C DSPF Section - Sharp Copying Equipment Service Manual (repair manual). Page 5

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MX-M1100  DSPF SECTION  C – 5
2. Operational descriptions
Document sheets are automatically fed and transported for continuous scanning.
The front and the back surfaces of duplex sheet documents can be scanned at the same time.
A. Document tray lift operation
When a job is started, the document tray is lifted until a document
at the top in the document tray turns on the document upper limit
sensor (STUD).
The pressure between the document at the top in the document
tray and the take-up roller is maintained at a constant level to
improve the paper feed capability.
When paper to be scanned is exhausted, the document empty sen-
sor (SPED) turns off and the document tray moves down automati-
cally until the lower limit sensor detects it.
Up and down movements of the document tray are performed by
the lift motor (normal rotation, reverse rotation) and the lift gear.
B. Document feed, transport, scan, paper exit, 
and operating speed
The document fed by the pick up roller is sent through the paper
feed roller and the transport roller to the resist roller section.
In the resist roller section, the document lead edge and the scan
start position are synchronized.
The document is transported to the scan section. After being
scanned, the document is sent to the document exit tray by the exit
rollers.
C. The original scan
The CCD is located inside the DSPF this items scan the document
images. 
This CCD allows for simultaneous scan of a duplex document.
D. Double-feed sensor operation
(1) Outline of the operation
The double-feed sensor is on the DSPF of the 110/95 models, and
it detects double feed.
Paper transport stops when double feed is detected.
The ultrasonic generator generates sound frequency.
The frequency level of the ultrasonic sensor changes (lower fre-
quency) when double sheet feeding occurs. Double sheet feeding
is then detected.
Block diagram
9 10
12
2
3
8
4
5
7
6
1
11
13 14
15
16
No.
Name
Function/Operation
1
Document tray
Max.250 sheets (80g/m
2
, 21lbs Bond) Max. height 32.5mm.
2
Paper pickup roller
Picks up a document and transport it to the paper feed roller.
3
Paper feed roller
Performs paper feed operation of a document.
4
Separation roller 
Separates a document, preventing double feed.
5
No. 1 resist roller (Drive) 
Performs resist of document transport.
6
DSPF double feed sensor 
Detects double feed.
7
Transport roller 1 (Drive)
Transports paper from No. 1 resist roller to No.2 resist roller.
8
Transport roller 2 (Drive)
Transports paper from the transport roller 1 to No.2 resist roller.
9
No. 2 resist roller (Drive)
Synchronizes the document lead edge and the scan start position.
10
CCD PWB
DSPF (back) scanning CCD.
11
Transport roller 3 (Drive)
Transports paper from the platen roller to the transport roller 4.
12
Lens
Reduces the document images (optical) and radiates them onto the CCD PWB.
13
Transport roller 4 (Drive) 
Transport paper from the transport roller 3 to the transport roller 5.
14
DSPF copy lamp
Radiates lights onto a document for the CCD to scan the document image.
15
Transport roller 5 (Drive)
Transport paper from the transport roller 4 to the paper exit roller.
16
Paper exit roller (Drive) 
Discharges paper.
(1 sheet)
(Double feed)
Ultrasound
Secondary
radiation
Reflect
Paper
Ultrasonic
generator
Ultrasonic
sensor
Ultrasonic sensor
(DFS PWB)
Ultrasound
generate
Digital signal
output
DSPF
control
PWB
Ultrasonic
generator
Amplifier
Detection
circuit
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