Td Sensor Reference Voltage - Ricoh MP 7503SP Field Service Manual

5. Detailed Descriptions

TD Sensor Reference Voltage

The TD sensor reference voltage must be initialized the first time the development unit is filled with
developer at machine installation and every time the developer is replaced. The sensor control voltage is
adjusted until the output is 3.0±0.1V, and after the control voltage is set, Vt is sampled 100 times, and
then these samplings are averaged and used to set the standard reference value for Vt.
Here are some important points to remember:
• After the developer has been replaced, it must be initialized with SP2801.
• After the TD sensor has been replaced, it must be initialized with SP2801.
• If a partially used development unit from another machine is installed, open SP2220 (Vref Manual
Setting) on the loan machine to display the Vref value of the TD sensor, and then enter this value in
the other machine with the same SP. Next, open SP2906 (TD Sensor Control Voltage Setting) to
display the setting, and then enter this setting on the other machine with the same SP.
• These initial settings are stored in NVRAM. Before replacing an NVRAM, always print an SMC
report so you can read the settings off the report and enter them manually after NVRAM has been
replaced.
Abnormal TD Sensor Output
If a problem occurs with the TD when developer in initialized:
• SC codes are issued and the machine will display the immediately previous value of SP2906 (TD
Sensor Control Voltage Setting).
• If Vt is "0" then the machine returns SC360-01.
• After the start of adjustment, if the TD sensor output does not enter the target range of Vt =
3.0±0.1V within 20 sec., the machine returns SC360-11.
If a problem occurs with the TD sensor during a print job, one of the following conditions has been
detected:
• TD sensor outut Vt is 0.5V or lower (SC362-00).
• TD sensor outut Vt is 4V or higher (SC361-00).
The SC code is logged, and the toner supply moves into the ID Sensor Supply Mode + Pixel Count
Mode, or the Pixel Count Mode (using ID sensor reading as reference).
ID Sensor Control
At power on, or after the specified number of prints (Default: 10) and at job end, the ID sensor reads the
ID sensor pattern on the drum. The purpose of the ID sensor reading is to calculate the ID sensor pattern
density (Vsp/Vsg) and then use this result to determine the target reference voltage of the TD sensor. The
timing of when these ID sensor patterns are created on the drum is controlled by turning process control
on/off in the SP mode.
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