CHAPTER 4 IMAGE FORMATION SYSTEMCOPYRIGHT © 1999 CANON INC. CANON NP6512/6612/7120/7130/7130F REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON) 4-31D. Primary Charging Roller Cleaning Control1. OutlineThe machine is equipped with an automatic cleaning mechanism used to remove toner andpaper lint sticking to the primary charging roller.2. OperationsThe primary charging roller is cleaned by turning on the primary charging roller cleaning sole-noid (SL6), thereby forcing the cleaning pad against the roller.The cleaning pad is forced against the roller for about 1.5 sec. While the roller is being cleaned,all other high-voltage outputs are turned off except the developing DC bias (cleaning bias).Cleaning is executed for the following three independent conditions:• Condition 1During last rotation after making 10 copies (cumulative).For this condition, cleaning is executed only once between when the power is turned on andwhen it is turned off. The number of copies made after these ten will be stored in memory by theDC controller PCB and added to the number of copies made after the power is turned on next time.• Condition 2During last rotation after making 20 copies (cumulative).For this condition, there is no limit to the number of times cleaning is executed, and the cumu-lative number is cleared when the power is turned off and then on.• Condition 3When user mode ‘U1’ has been executed.
