HP 2100 Service Manual - Page 78

Sequence of Operation The formatter system and the Engine Controller Assembly system share information during printer operation. The Engine Controller Assembly-to-formatter connector forms a link which operates as a serial data bus. This lets printer status, command information, and dot-image data to be passed between the two systems. The events described in the table below and shown in "Timing Diagram" (page 70) take place during normal printer operation. Table 5-1. Print Period Descriptions (see "Timing Diagram" (page 70)) Period Timing Purpose WAIT Standby (STBY) Initial Rotation (INTR) PRINT Last Rotation (LSTR) From the time power is switched on to the end of the main motor's initial rotation. Clears the drum surface potential and cleans the Transfer Roller. Also detects whether or not the toner cartridge is installed. From the end of the WAIT period until Maintains the printer in a ready state. the input of the PRINT signal from the Formatter. OR: From the end of the Last Rotation period until either the input of the PRINT signal from the Formatter or the power is switched off. From the input of the PRINT signal from Stabilizes the sensitivity of the the Formatter until the paper reaches photosensitive drum in preparation for the top-of-page sensor. printing. From the end of the INTR period until 2 Forms images on the photosensitive seconds after the top-of-page sensor drum based on the /VDO signal from detects the trailing edge of the paper. the Formatter and transfers the image to the paper. From the completion of printing until the Delivers the last sheet of paper. Also main motor stops rotating. cleans the Transfer Roller. Returns to the INTR period if the Formatter sends another PRINT signal. Otherwise, returns to the STBY period. 68 5 Functional Overview C4170-90959