Chapter 77-9sub hopper to the developing assembly.The machine's toner cartridge serves as a hopper (as found in past models).F-7-177.8.3 Controlling the Drive of the Toner Cartridge 0006-5996iR2270 / iR2870 / iR3570 / iR4570 / / iR2270N / / iR2870N / / iR3570N / / iR4570N / iR2230 / / / iR3530 /When a request is made for a supply of toner, the toner cartridge drive motor rotates in the direction shown in the following figure; its drive is transmitted from thedrive motor to the toner cartridge, thus rotating the toner cartridge.F-7-187.8.4 Toner Supply Control 0006-5995iR2270 / iR2870 / iR3570 / iR4570 / / iR2270N / / iR2870N / / iR3570N / / iR4570N / iR2230 / / / iR3530 /Supply of Toner from the Toner Bottle to the Sub HopperIf the "absence of toner inside the sub hopper" is detected while the main motor is rotating, the bottle motor is rotated intermittently (on for 3 sec, off for 2 sec), andthe length of time during which the absence is detected is checked using a counter that increases its count for each on-off cycle. When the count reaches 20 (about100 sec), the machine will assume that the sub hopper has become empty, and will indicate the Add Toner message on its control panel. The counter is reset whenthe presence of toner inside the sub hopper is detected during any on-off cycle.If the "absence of toner inside the developing assembly" is detected while the main motor is rotating and the developing clutch is on, the machine rotates the subhopper feedscrew motor intermittently (on for 1 sec, off for 1 sec). The rotation is monitored by a counter that increases its count when the developing sensor stateis off during a single on-off cycle; when its reading reaches 20 (about 40 sec), the machine will assume that its developing assembly is more or less empty (i.e.,there is a possibility of the ongoing generating black prints if printing continues), and will issue a No Toner error, suspending image formation operation. The coun-ter is reset when the presence of toner is detected inside the developing assembly.[1][2][3][4]