Sharp MX 3501N - Color Laser - Copier, Service Manual

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MX3500N LSU SECTION H – 2
2. Operational descriptions
A. LSU section
(1) Outline
Image data sent from the image process circuit through the mother
are converted into laser beams to be radiated onto the OPC drum
surface. The LSU unit is composed of the primary system including
optical elements such as lasers and the polygon mirror and the mir-
ror which assures the optical path and the scan system which
includes the optical elements including the polygon mirror and the
mirror which assures the optical path.
(2) Composition
(Primary system)
(Scan system)
(On the polygon mirror)
(3) Outline of LSU specifications
Signal name Name Function/Operation
PGM Polygon motor Laser beam is reflected at the constant speed rotation.
LSUSS LSU shutter solenoid Opens or closes the LSU shutter.
LSUFAN LSU cooling fan motor Cools the polygon motor.
No. Name Function/Operation
1 LD PWB (K) Controls laser beam flashing and the output value.
2 LD PWB (C)
3 LD PWB (M)
4 LD PWB (Y)
5 Cylindrical lens Converges laser beams and focus.
6 f
θ
lens 1 Laser beams are refracted so that the laser scan speed on the OPC drum is even in both ends and at the center.
7 f
θ
lens 2
8 Reflection mirror Secures the path for laser beams.
9 Cylindrical lens Converges laser beams, and focus on the OPC drum.
10 OPC drum Forms electrostatic latent images according to laser beams.
11 Convergence lens for BD Converges laser beams to the BD PWB.
12 BD PWB Detects the timing for starting laser scanning.
13 LSU CNT PWB Laser beams are controlled and the polygon motor control signal is generated according to the PCU PWB control
signal and image data.
14 LSU therminstor Measures the temperature in LSU.
Model Number of
mirror
surfaces
Rotating speed Bearing Remark
MX-3500N
MX-3501N
MX-4500N
MX-4501N 7 surfaces 33813 rpm
(color/35 sheets)
45556 rpm
(Monochorome/
45 sheets)
AIR
Effective scan width: 307mm
Resolution: 600dpi
Beam diameter: Main scan = 50 to 65µm, Sub scan = 60 to 75µm
Laser power: Max. 0.302mW
LD wavelength: 770 to 795nm