B. Detecting the Level of Toner and Controlling the SupplyOperationThe toner inside the developing assembly is monitored by the toner sensor (TS2).When the toner inside the developing assembly falls below a specific level while thedeveloping clutch (CL8) remains on during copying, the developing assembly toner levelsignal (DTEP*) goes ‘0’ and is communicated to the DC controller.When the DC controller has detected the developing assembly toner level signal(DTEP*) for 0.3 sec or more, it sends the hopper motor (toner supply) drive signal(M11ON), causing the hopper to supply toner.When the toner inside the developing assembly has reached a specific value and theDC controller PCB has detected the developing assembly toner level signal (DTEP*=1)for 0.7 sec or more, the DC controller PCB stops the hopper motor 1 (M11).If the toner sensor (TS2) goes out of order for some reason or if a fault in the hop-per prevents supply operation and, as a result, the DC controller detects the developingassembly toner level signal (DTEP*=0) for 120 sec or more, the DC controller will indi-cate ‘E020’ and stop copying operation.The level of toner inside the hopper is monitored by the hopper toner sensor (TS1)while the hopper motor 1 (M11) is operating to supply toner or while toner is beingstirred.When the toner inside the hopper falls below a specific level, the hopper level detec-tion signal (TEP*) goes ‘0’. When the DC controller PCB has detected the signal for 1sec or more, it will indicate the Add Toner message on the control panel. At this time, theCopy Start key on the control panel will change to red.Figure 4-202Developing assemblytoner level detection signal (DTEP*)Hopper toner leveldetection signal (TEP*)INTRHopper motor 1 (M11)Developing clutch(CL8)SCFW SCRV SCFW SCRV LSTR STBY*1 *2*3Add Tonermessage Add Toner messageOFF*1 Resumes supply operation when the developing assembly toner level detection signal= 0 has been detected for 0.3 sec or more.*2 Suspends supply operation when the developing assembly toner level detection signal= 1 is detected for 0.7 sec.*3 Drives the hopper for 2.0 sec and then holds it for 1 sec, supplying toner by repeating this sequence.Copy Start keyONCHAPTER 4 IMAGE FORMATION SYSTEM4-30 COPYRIGHT © 1997 CANON INC. CANON NP6560/NP6360/NP6260 REV. 0 NOV. 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
