- Hewlett-Packard Printers Service Manual

5-46 Functional Information
Duplexer
The operation sequences of the Duplexer are controlled by the
Duplexer Driver. A 4-bit microprocessor is used in the Duplexer
Driver, which controls the sequences of the Duplexer and the serial
communication with the Engine Controller Board.
The Duplexer Driver drives the Solenoid, Motors, and Fan according
to commands sent from the Engine Controller Board to the Duplexer
and Duplex Pickup command via serial communication. The Duplexer
also returns its status to the Engine Controller Board.
+24VDC is supplied to the Duplexer from the printer, and +5V for the
ICs is generated from the +24VDC inside the Duplexer Driver.
Reversing and Duplexer Pickup
The paper is fed to the Duplexer by the Top Output Bin Deflector. This
Top Output Bin Deflector moves in conjunction with the Top Output
Bin. However, the Top Output Bin Deflector is controlled by the
Duplexer Solenoid (SL701) when the Top Output Bin is closed.
The feed direction of the paper in the Duplexer is controlled by the
Reversing Roller. The paper is then transported by the Oblique Roller
and Feed Roller so that its edge contacts with the left panel to correct
its skew.
The Duplexer has two stepping motors, the Reversing Motor (M701)
and the Duplex Feed Motor (M702). Normal and reverse rotations are
controlled by the Duplexer Driver.