HP 1100AHP - Manual (Page 58)

56 Functional Overview C4224-90962
Document scanner system (optional)
The document scanner system consists of the optical system and document pickup and feed
systems.
The optical system, also known as the contact image sensor, contains the following:
• light-emitting diode (LED) array
• contact glass
• rod lens array
• phototransistor array
The LED array, which emits light from two LEDs, is controlled by the formatter. Light
reflected from documents passes through the rod lens array and focuses on the
phototransistor array.
The phototransistor array consists of 2,574 phototransistors: 11 driver chips amplify the light
reception output in units of 234 phototransistors. The image data is converted and sent from
the driver circuits to the formatter.
The document pickup and feed systems contain a pickup roller and CIS roller, both of which
are driven by the document scanner motor.
The following figure shows a simplified Document Scanner document path.