Ricoh Aficio Color 4006, Руководство по обслуживанию

Страница: 57 / 487

PROCESS CONTROL 24 February, 1999
2-8
Figure A shows the relationship between the output of the normal reflection ID
sensor and the amount of Y, C, or M toner attached to the drum. This shows that
the ID sensor output (Vsp) results from not only the light reflected from the toner
but also the component of light reflected from the drum.
With this old sensor type, the machine was unable to accurately detect high values
of M/A for colored toner (i.e., to the right of the minimum in the V
SP
curve at Vmin.
The diffused reflection ID sensor, on the other hand, picks up little light that is
reflected from the drum. So, the relationship between the diffused reflection ID
sensor output and the amount of toner on the drum is linear, as shown in Figure B.
This means that high densities of colored toner can be measured accurately.
K toner
The ID sensor output for K toner tends to decrease as the density of toner on the
drum increases. Therefore, the relationship between the ID sensor output and the
amount of K toner on the drum is as shown in Figure C.
Step 5: Toner Amount Calculation
The amount of toner on the drum (M/A, mass per unit area, mg/cm
2
) is calculated
for each of the 16 grades of the sensor pattern from the ID sensor output value
(Vsp) from each grade of the pattern.
A259A009.WMF
A259A010.WMF
Figure B Relationship between the
output of the diffused reflection ID
sensor and the amount of toner on the
drum for C, M, and Y toners
Figure C Relationship between the
output of the diffused reflection ID sensor
and the amount of toner on the drum for
K toner