Ricoh SP5 Series Service Manual page 101

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DEVELOPMENT AND TONER SUPPLY
V
and V
detection
SP
SG
The ID sensor detects the following voltages.
• V
: The ID sensor output when checking the drum surface
SG
• V
: The ID sensor output when checking the ID sensor pattern
SP
In this way, the reflectivity of both the drum and the pattern on the drum are
checked.
The ID sensor pattern is made on the drum with the charge corona and laser diode.
V
/V
is detected every 50 copies (or at the end of a copy job of more than 50
SP
SG
pages) to update the TD sensor reference voltage (V
changed using SP2-210. This compensates for any variations in the reflectivity of
the pattern on the drum or the reflectivity of the drum surface.
V
Update
REF
V
is updated using V
REF
end of a copy job of more than 50 pages), and during process control initial setting.
See "V
Update" in the Process Control section for details.
REF
V
detection
T
The toner density in the developer is detected once every copy cycle after the
trailing edge of the image passes through the development roller.
Image pixel count
For each copy, the CPU adds up the image data value of each pixel and converts
the sum to a value between 0 and 255. (The value would be 255 if the page was
completely black.)
Gain Determination
GAIN is another factor in the toner supply clutch on time calculation. Its value can
be 0, 1, 2, 3, or 4. It is calculated every copy using "V
Toner Supply Clutch On Time Calculation
The toner supply clutch on time for each copy is decided using the following
formula: (GAIN × Image pixel count × 0.7mg/cm
The toner supply rate can be changed using SP2-209.
Image pixel count control
This mode should only be use as a temporary countermeasure while waiting for
replacement parts, such as a TD sensor. This mode controls the toner supply using
the same formula for the toner supply clutch on time. However, the GAIN value is
fixed at 0.7.
/V
and V
This is done every 50 copies (or at the
SP
SG
T.
2-76
). This interval can be
REF
– V
".
REF
T
/Toner Supply Rate) + 50ms
2
June 30, 1998

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