Oce 7050, Техническое и сервисное руководство, Страница: 160 / 275

ed. 6 12 Paper roll feed 503
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4 Length measurement
The length which has to be cut, is converted into a specific number of pulses
for the drive motor upper roll 12M1 (drive motor lower roll 12M2). The count-
ing of this number of pulses starts when the paper has reached the lead sensor
12B3. When the paper is allready at the knife position, the distance between
the knife and the lead sensor 12B3 is taken into account. Several factors influ-
ence the length of the cut paper:
1 When the diameter of the feedrollers is not the same for every machine, more
or less paper will be transported for the same number of pulses. This can be
corrected by means of an adjustment (12 Pap.
301 adj. 1 ).
2
When the distance between lead sensor 12B3 and knife is not the same for eve-
ry machine, the cut length will differ per machine. This can be corrected by
means of an adjustment (12 Pap.
301 adj. 2 ).
3
When a copy is made, the moment of synchronisation of the original and the
paper of the roll is started when the paper of the roll activates paper input sen-
sor 15B1. This can be different for every machine, thereby influencing the head
margin. This can be corrected by means of an adjustment (12 Pap.
302 adj. 3 ).
5 End of roll
The core of the paper roll rotates during copying. A pulse-disc, the upper roll
empty sensor 12B4 ( lower roll empty sensor 12B5) is driven by the core. As
long as the core rotates, pulses are generated. When no more pulses are gener-
ated, then the roll is empty or the paper is connected to the core. In both cases
an end of roll signal is generated.
6 Knife
The knife motor 12M3 moves a circular knife over a linear knife from left to
right and vice versa. The knife sensor left 12B1and the knife sensor right 12B2
are used to detect if the circular knife is in the left or in the right position. These
sensors are also used to brake the speed of the knife motor 12M3. When during
a cut one of the sensors is activated, the direction of the knife motor 12M3 is
reversed or short-circuited.
At the time of initialization, one of the sensors must be active. When this is not