Sharp UX-510A Service Manual page 34



UX-510ATH
FO-1470TH
Paper feed spring


Separation
rubber

3-5. Documents requiring use of copy
1) Documents smaller than 128mm x 148mm.
2) Documents thinner than the thickness of 0.06mm.
3) Documents containing creases, folds, or curls, especially those whose
surface is curled (maximum allowable curl is 5mm).
4) Documents containing tears.
5) Carbon-backed documents. (Insert a white sheet of paper between
the carbon back and the document carrier to avoid transfer of carbon
to the carrier.)
6) Documents containing an easily separable writing material (e.g., those
written with a lead pencil).
7) Transparent documents.
8) Folded or glued documents.
4. Document release
4-1. General
To correct a jammed document or to clean the document running sur-
face, pull the operation panel lock lever under the front center of the
operation panel. To open the upper document guide, the operation panel
must be opened first.

Last page of document

First page of
document
Paper feed arm
Paper feed roller
Fig. 4
5. Optical system
(1) General view
Rear sheet
Reader
glass
Mirror 3
(2) Composition
The optical system is composed of the document feed mechanism, the
LED lamp, the reflecting mirrors, the focusing lens, the CCD sensor, and
the read process circuit.
5-1. LED Lamp/Lens
The LED lamp is used to project light to the document.
NOTE: Take care for the position of the red mark on the lens. (Top of
the light-projected side)
5-2. CCD
The CCD (charge coupled device) image sensor consists of a photodiode
array which converts the intensity of light reflected from the document
surface into series of analog voltages which are then stored in an ana
log shift register. The series of analog voltages are then converted into a
digital equivalent by a black/white binary logic circuit.
(Example) Scan signal output waveform
100%
50%
minimum
Maximum document width, 216mm
1) The minimum output from the CCD at the maximum scan width of
document (216mm) must be more than 50% of the peak value.
2) The peak output must be about 0.2 ~ 0.6 under room temperature to
avoid CCD saturation.
3 – 2
CCD PWB
Document
Red mark
LED lamp
Mirror 2
CCD
Lens
Mirror 1
Fig. 5
Peak
Fig. 6
Scan line
length