Laser Scanner Area - Toshiba DP120F Service Manual

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3.3 Laser Scanner Area

3.3.1 Outline

Polygon motor

Cylinder lens

Collimator lens

Start sensor

The laser scanner area consists of the laser diode part, polygon part, and reflecting part.

The laser diode part generates a laser beam according to the laser diode drive signal sent from

the Main PBA. The laser beam is compensated to parallel rays through the Collimator lens and

then passes through the Slit and Cylinder lens. A laser beam of parallel rays is sent to the

polygon part. The laser diode part checks the current value flowed to the laser diode by each

line to keep the laser beam volume stable. The polygon part consists of the Polygon motor and

Polygon mirror. The Polygon motor turn the Polygon mirror at a uniform rate for laser beam

scanning. The laser beam generated in the laser diode part is sent to the reflecting part of the

Polygon mirror. The Fθ lens and Reflecting mirror1, 2 bend the optical path of the laser beam

and then the beam is focused on the drum.

As the Polygon mirror turns at a uniform rate, the laser beam scans on the drum at a uniform

rate. This operation forms the image on the drum surface like a television.

The laser beam is also sent to the Start sensor by the Polygon motor and Polygon mirror.

Each time the Start sensor receives the laser beam, it sends a signal to the Main PBA. The

Main PBA uses this signal to determine the print start position of each line.

DP120F/DP125F Mechanical Description

Polygon mirror

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