Ricoh A-P4, Service Manual

Page: 322 / 381

transfers to the drum. The ID sensor measures the density of pattern [B], and Vsdp, the output voltage, is
compared with Vsg which was read from the bare drum at the same time.
Correction for Paper Width and Thickness (By-pass Tray only)
The by-pass tray can be used for non-standard paper narrower than sizes accepted by the paper trays.
Thicker paper, OHP sheets, etc. can also be loaded in the by-pass tray but adjustments must be performed
with the SP modes listed below in order to avoid jams and quality problems.
SP Mode SP Name
SP2001-01 Charge Roller Bias Adjustment Default: –1,480 V
SP2001 02 ID Sensor Pattern Default: -200 V
SP2309-01 Paper Lower Width [a] Width limit. Default: 150 mm
SP2309-02 Paper Upper Width [b] Width limit. Default: 216 mm
SP2914-01 Process Ctrl Set – C alpha Adjust 10 V/step. Default: +150 V
SP2914-02 Process Ctrl Set – C beta Adjust 10 V/step. Default: 0
The way that these SP modes are used is shown below.
For example, with the default settings, if the paper width fed from the by-pass tray is 100 mm, the charge
roller voltage will be –1,480 + 150 V.
ID Sensor Pattern Production Timing
An ID sensor pattern is created on the drum:
• Every time the system is powered up
• After every 10 prints
Drum Charge
321
6