Canon NP-70 Service Manual page 57

3-16
NP•70
Block
Actions Occurring
The following are the significant actions occurring in the copier when copying
operations are performed. It should be noted that a path is provided for half
and full size copying operation.
C
COPY
J
Depressing the COPY button turns ON relay K1 through the activation of MS7.
The energizing of K 1 causes C 16 to start charging (through D 16) to initiate the
operation of the illumination lamps and drum for copying. It should be noted
that K1, once energized, is self-holding; thus, at least one copy cycle will occur
even if the STOP button is depressed.
COPY-
"ON
„
Capacitor C 16 completes charging and turns ON the illumination lamps, drum,
overall-exposure lamp, and coronas due to the energization of their control
relays. It should be noted that K7 energizes at this time because Q 16 was placed
STEP 1C
in continuous conduction by the actions occurring in STEP 3S
The actuation of MS3A by the rotating drum causes the K7 delay hold to be
STEP 2C
turned ON (reference STEP 4S ).
The actuation of MSS by the rotating drum causes SL1 to turn ON in prepa-
ration for the forward movement of the copyboard. SL6 is also enabled for
toner feeding if density is low (reference -the ATR ckt. flowchart).
STEP
3C
As MS 1 A is actuated, the copyboard forward drive clutch (C ~ 1) moves the copy-
board forward for the start of the first copy cycle. After this step, flow pro-
ceeds to either "Half-size" or "Full-size" operation.
STEP 4C
If the copy being made is the last copy, the copy selector will be released by the
forward motion of the copyboard.
STEP SCH
The actuation of MS2A by the rotating drum will enable SL7 for the deacti-
vation of the copier should a physical jam have occurred in the machine. The
step is effective only for the second or later copy cycle. In the case of the first
copy cycle, K 11 is not yet energized and, therefore, SL7 cannot possibly ope-
rate. (reference -the Jam Detection ckt. flowchart).
STEP
6CH
The actuation of MS 14 by the advancing copyboard causes the pickup of paper
as well as the other actions shown. The purpose of energizing K 10 is to provide
a path for energizing relay K11 when the next MS3A pulse occurs.
STEP
7CH
STEP 8CH
The jam detection interval begun in STEP 6CH comes to an end. This step,
also, is only effective for the second or later copy cycle.
Second Printingtilune, 1974
© CANON INC.