Sensor Control Mode - Ricoh MP 7503SP Field Service Manual

• Sensor Control
• Pixel Count
Either can be selected with SP2208 with Sensor Control as the default, or normal operation mode).

Sensor Control Mode

In sensor control mode the machine uses the input of the ID sensor and the TD sensor: the TD sensor
reads the toner density during development and the ID sensor reads the density of the toner on the drum.
The purpose of monitoring the toner density is to keep a fixed amount of toner in the developer while
keeping the density level suitable for the images being printed.
Here is a brief overview of toner density control:
1. The TD sensor reads the density of the toner in the developer for every copy. This reading is output
by the TD sensor as Vt. Vt (the TD sensor reading) and Vref (the targeted control reference voltage
for the TD sensor) are used to calculate the value of the GAIN. (0, 1, 2, 3, 4).
2. The equation below is used to calculate the clutch ON time.
Where, if GAIN = 0, startup time of 16 ms is reset to 0.
• Image pixel count: The density for every dot in the output data for the page is calculated
(Example: 255 for A3).
• Target density: 0.7 mg/cm
• Toner supply: 850 mg/s (This default setting can be adjusted with SP2209).
• Clutch startup time: 16 ms (The actual time required for the toner to reach the hopper after the
clutch turns on.)
3. At 10-copy intervals (adjustable with SP2210) and at job end the ID sensor measures Vsg, Vsp.
4. Vref (target reference voltage) from the TD sensor is updated with the new readings of Vsp, Vsg.
Pixel Count Mode
The ON time is calculated with the same formula described above, but the GAIN value is fixed at 0.7.
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Print Process (Main Engine Components)
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