HP 4550 Service Manual - Page 120

Toner carousel The toner carousel holds the printer's four toner cartridges: K (black), M (magenta), C (cyan), and Y (yellow). The carousel motor (M3) rotates the carousel, and the toner cartridge motor (M5) provides the drive for the positioning cam and the developer sleeve. The carousel contains three sensors: developing carousel position sensor (PS10), toner cartridge contact/separation sensor (PS11), and the toner level sensor (PS12). These sensors, as well as the detailed operation of the carousel assembly, are discussed on the following pages. Figure 5-20 Toner carousel assembly Table 5-1 Toner carousel assembly components Reference Description M5 Toner cartridge motor M3 Carousel motor PS10 Carousel position sensor PS11 Toner cartridge contact/separation sensor PS12 Toner level sensor Operation The DC controller activates the carousel motor (M3) and rotates the carousel. As the carousel rotates, the position sensor (PS10) monitors the carousel for the stop position flags. Each stop position flag is used as a development and toner cartridge removal flag (see Figure 5-21). When a flag is detected, the DC controller monitors the time it takes the flag to pass the sensor (PS10). Each flag is a different width and therefore takes various times to pass the sensor. This time lapse is used by the DC controller to determine which development/removal stop position flag has passed the sensor. When the carousel turns to the correct position, the DC controller stops the carousel motor (M3) and the carousel from rotating any farther. 118 Theory of operation C7085-90921