6 – 6Chapter 6 Principles of Operation2. Flow of Print DataThe NIC (Network Interface Card) of the printer connected with a network receives apacket signal in a bit stream from a client or server of the network, and decomposesthe packet signal received next into a data format adapted for a layer from which thedata is sent to the Controller. The Controller processes the data from the NIC by thesame method as for data received from the host computer via a parallelport. (These two types of data are referred to as host data.) PWBA ESS acts to bufferthe rasterized bit-image host data or converts host data in PDL (Page DescriptionLanguage) into rasterized bit-image data. The PWBA ESS sends each line of therasterized bit-image data to the MCU of the HVPS/MCU whenever the laser beammakes a scan. This signal carrying image data (/VDO signal) is converted into LVDSsignal by the MCU of the HVPS/ MCU, and is sent as XP.DATA+ and XP.DATA-signals to the ROS ASSY, where the signal is converted into a laser beam. The beamis emitted with a quite small diameter. The beam is turned ON and OFF according tothe video signal. The laser beam is reflected off the surface of a rotating polygonmirror, so that the beam is concentrated to the surface of the drum of the EPCARTRIDGE by a series of lenses. As a result, an electrostatic latent image is createdon the drum surface.Print data (electrical signal) from the printer controller is converted into a print imagethrough the following flow.
