Toner Density Sensor Initial Setting; Toner Density Measurement; Vsp/Vsg Detection; Toner Supply Reference Voltage (Vref) Determination - Ricoh B022 Service Manual

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Toner density sensor initial setting

The TD sensor initial setting procedure is performed automatically when the new

PCU is installed in the machine. During TD sensor initial setting, the TD sensor is

set so that the TD sensor output to the value of SP2-926 (default: 2.5V). This value

will be used as the standard reference voltage (Vts) of the TD sensor.

Toner density in the developer is detected once every copy cycle. The sensor

output voltage (Vt) during the detection cycle is compared with the standard

reference voltage (Vts) or the toner supply reference voltage (Vref).

The ID sensor detects the following voltages.

• Vsg: The ID sensor output when checking the drum surface

• Vsp: The ID sensor output when checking the ID sensor pattern

• At the end of a job, if an ID sensor pattern has not been made for a certain

number of sheets (default: 0 sheets = disabled)

The number of sheets can be changed using SP2-995-2.

In this way, the reflectivity of both the drum surface and the pattern on the drum are

checked. This compensates for any variations in the reflectivity of the pattern on

the drum or the reflectivity of the drum surface.

The ID sensor pattern is made on the drum by charge roller and laser diode.

Vsp/Vsg is not detected every page or job; it is detected at the following times to

decide Vref.

• During warming up at power on

• If the machine starts warming up after a certain time (default: 30 minutes)

has passed since entering night mode or low power mode

The 30-minute interval can be changed using SP2-995.

The toner supply reference voltage (Vref) is the threshold voltage for the toner

supply determination. Vref is determined using the following data:

• ID sensor output (Vsp/Vsg)

• (Vts or the current Vref) - Vt

The reference voltage (Vts or Vref) is the threshold voltage for determining whether

or not to supply toner. If Vt becomes greater than the reference voltage, the

machine supplies additional toner.