Sharp MX-M950 / MX-MM1100 (serv.man15) Service Manual ▷ View online
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.
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.
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.
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.
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.
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
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
generator
Ultrasonic
sensor
sensor
Ultrasonic sensor
(DFS PWB)
Ultrasound
generate
generate
Digital signal
output
output
DSPF
control
PWB
control
PWB
Ultrasonic
generator
Amplifier
Detection
circuit
circuit
MX-M1100 DSPF SECTION C – 6
(2) Mechanism and operation of double-feed detection
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."
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."
3. Disassembly and assembly
A. Exterior section
(1) DSPF unit
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).
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).
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.
side to remove.
Unit
Parts
Page
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
MX-M1100 DSPF SECTION C – 7
a. Front cabinet / Rear cabinet.
1)
Open the upper door (a).
2)
Remove the screw (a), and remove the cover (b).
3)
Remove the screw (a), and remove the front cabinet (b).
* Disengage one pawl at the top and two pawls at the bottom,
* Disengage one pawl at the top and two pawls at the bottom,
and turn the cabinet from the bottom to the top to remove.
4)
Remove the screw (a), and remove the rear cabinet (b).
B. Paper feed section
a
a
b
a
a
b
Unit
Parts
Page
Document tray unit
A
DSPF document empty sensor
C - 8/ a
B
DSPF document length long
sensor
sensor
C - 8/ b
C
DSPF document length short
sensor
sensor
D
DSPF document width sensor
Paper feed unit
E
DSPF document tray upper
limit sensor
limit sensor
C - 9/ a
F
DSPF paper pass sensor 1
G
DSPF random sensor
Others
H
DSPF document tray lower limit
sensor
sensor
C - 9/ (3)
a
a
a
a
b
C
D
H
E
F
A
G
B
MX-M1100 DSPF SECTION C – 8
(1) Document tray unit
1)
Remove the front cabinet and the rear cabinet.
2)
Disconnect the connector (a). Remove the screw (b), and
remove the document tray unit (c).
remove the document tray unit (c).
a. DSPF document empty sensor
1)
Remove the front cabinet and the rear cabinet.
2)
Remove the document tray unit.
3)
Remove the screw (a) and the connector (b), and remove the
DSPF document empty sensor (c).
DSPF document empty sensor (c).
b. DSPF document length long sensor / DSPF document
length short sensor / DSPF document width sensor
1)
Remove the front cabinet and the rear cabinet.
2)
Remove the document tray unit.
3)
Disconnect the connector (a), and remove the DSPF docu-
ment length long sensor (b) and the DSPF document length
short sensor (c).
ment length long sensor (b) and the DSPF document length
short sensor (c).
4)
Disconnect the connector (a). Remove the screw (b) and the
shaft (c). Remove the E-ring (d) and the rotation tray (e).
shaft (c). Remove the E-ring (d) and the rotation tray (e).
5)
Disconnect the connector (a), and remove the DSPF docu-
ment width sensor (b).
ment width sensor (b).
(2) Paper feed unit
1)
Remove the front cabinet and the rear cabinet.
2)
Disconnect the connector (a), and remove the snap band (b).
Remove the screw (c), and remove the paper feed unit (d).
Remove the screw (c), and remove the paper feed unit (d).
b
c
b
b
a
a
b
c
a
a
b
c
b
c
d
e
a
a
b
a
b
b
c
d
c
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