Canon NP1550 Service Manual

Also see for NP1550: Service manual

I OPERATIONS AND TIMING IC. Jam DetectionThe copier has two sensors to sensewhether copy paper is being fed normally.• Pre-registration paper sensor (Q2)• Delivery paper sensor (Q5)Paper jams can be identified by themicroprocessor by reading signals from thesensors at predetermined times to check ifpaper is at or not at a sensor at that time,and thus identify if the paper is movingthrough the copier correctly.If a jam occurs, the copier memorizes thenumber of copies that have not yet beenmade and also the copier settings. Thisinformation is stored in the copier, even if thepower is cut off by opening the front door inorder to reset the copier.a. MultifeederThe microprocessor identifies a jam inany of the following four cases. Also, themicroprocessor judges that there is a jam ifone of the sensors detects paper when thepower is switched ON.1 . Pick-up assembly delay jamIf the copy paper does not reach thepaper sensor of the pick-up assembly withina specified period after paper pick-up-starts,the microprocessor will judge that a pick-updelay jam has occurred, and immediatelystop the operation of the copier. Also, theJAM indicator on the control panel will flashand a segment of the PAPER SELECT/JAMindicator will go ON.copy;keySTARTONrJAM indicatorflashesTSTBY INTR SCFW SCRV SCFW .SMultifeeder clutch (CL2) MEI= JAM check --1 sec.-* —1se<1 i 1Pre-registration paper sensor (Q2) Normal Abnorr ialMain motor (M1 Figure 3-41 (Multifeeder pick-up assembly delay jam)b. CassetteCOPY STARTkey ONPick-up clutch solenoid (SL1JAM checkSTBY INTR^SCFW SCRVJAM indicatorflashesi. SCFWPre-registration paper sensor (Q2)signalNormal Ab normalMain motor (M1)Figure 3-42 (Cassette pick-up assembly delay jam)COPYRIGHT© 1992 CANON INC. CANON NP-1S50 REV.1 SEPT. 1992 PRINTED IN JAPAN (IMPRIHE AU JAPON) 3-37