6570/5570 PRINTING
8 - 6
Mar. 1999 © TOSHIBA TEC
(5) f
θ
lens 1 and 2
These lenses perform the following compensations on the laser light reflected by the polygonal
mirror.
1
Equidistant scanning
The laser light reflected on the polygonal
mirror is scanned at the same angle as the
polygonal mirror is rotated at the same
speed. That is, when the scan is completed,
the dot-pitch on the drum becomes the wide
spaces at both edges and the narrow
spaces in the center. So, in order to make
the dot pitch equidistant, laser light is com-
pensated so that it is scanned on the drum
at equal speeds.
2
Pyramidal error compensation
The reflecting plane of the polygonal mir-
ror is tilted in either of two directions with
respect to the perfect vertical. Deviation of
the laser light (with respect to the perfect
horizontal) caused by this reflected plane’s
pyramidal error is compensated.
3
Laser beam sectional shape
The sectional shape of the laser beam on
the drum is compensated.
(6) HSYNC detection PC board
After the laser beams are scanned by any reflecting plane of the polygonal mirror, they are reflected
by the HSYNC detection mirror to become incident to the PIN diode on the HSYNC detection PC
board. The primary scanning synchronizing signal is formed by detection of these laser beams. The
pitch (42.3
µ
m) between the four laser beams and the laser beam power are detected on the drum
surface.
Wide
Narrow
Drum
Lens 1
Lens 2
Equidistant
Mirror plane is tilted.
Deviation
Summary of Contents for 4580
Page 1: ...SERVICE MANUAL DIGITAL PLAIN PAPER COPIER 8070 6570 5570 4580 ...
Page 231: ...6570 5570 DEVELOPER UNIT 12 28 Mar 1999 TOSHIBA TEC 3 Draw out the toner filter ...
Page 252: ...8070 6570 5570 4580 FUSER UNIT 14 6A Mar 1999 TOSHIBA TEC ...
Page 369: ...8070 6570 5570 4580 ADF 16 78 Mar 2000 TOSHIBA TEC 16 13 PC Board 1 PWA F LGC 794 ...
Page 370: ...Mar 2000 TOSHIBA TEC 16 79 8070 6570 5570 4580 ADF 2 PWA F SEN 794 ...
Page 374: ...Mar 1999 TOSHIBA TEC 18 1 6570 5570 PC BOARD 18 PC BOARD 1 PWA F SYS 300 ...
Page 375: ...6570 5570 PC BOARD 18 2 Mar 1999 TOSHIBA TEC 2 PWA F MTB 300 ...
Page 376: ...Mar 1999 TOSHIBA TEC 18 3 6570 5570 PC BOARD 3 PWA F LGC 300 ...
Page 377: ...6570 5570 PC BOARD 18 4 Mar 1999 TOSHIBA TEC 5 PWA F MOT 300 4 PWA F ADU 300 ...
Page 378: ...Mar 1999 TOSHIBA TEC 18 5 6570 5570 PC BOARD 6 PWA F SLG 300 7 PWA F SDV 300 ...
Page 379: ...6570 5570 PC BOARD 18 6 Mar 1999 TOSHIBA TEC 8 PWA F PLG 300 ...