Riso V8000 Series, Technical Manual

Page: 80 / 362

[5 - 2]
CHAPTER 5. SECOND PAPER FEED SECTION
Mechanism
1. Second Paper Feed Mechanism
The second paper feed mechanism is operated by the rotating timing roller (the guide roller rotates due to
drag torque). Rotary drive is provided by the sector gear, which in turn is driven by the timing cam.
The timing roller incorporates a one-way core that permits it to rotate when the timing gear rotates
clockwise, but not when the timing gear rotates counterclockwise. A load is applied on the timing roller by
the timing clutch and timing brake to ensure that it stops immediately when not being driven.
The timing clutch is activated at 195° from position T on the paper drum, and is deactivated at 358°.
The guide roller gear cam brings the guide roller into contact with the timing roller during the first paper
feed operation, then moves the guide roller away at the same time that the timing roller stops rotating.
Paper feed status within the second paper feed section is monitored by the 2nd paper sensor and the
multiple paper feed detection sensor.
The multiple paper feed detection sensor checks whether multiple paper feeding has occurred by
measuring the light transmissivity of the paper. Printing stops if a multiple paper feed occurs.
Light transmissivity is measured 200 times within the 35 mm to 157 mm range at the leading edge of the
paper, and a multiple paper feed is determined to have occurred if the measured value falls outside a
range equal to 75% to 150% of the mean value set by Test mode No.457.
Multiple paper feed detection is also enabled for printing with the “Test print” key.
2. Paper Pass Guide Mechanism
The paper pass guide is used to transfer the paper from the second paper feed section to the paper
drum. The paper pass guide is brought toward the paper drum as the leading edge of the paper is
gripped by the paper drum.
The paper pass guide is moved up and down by the cam on the guide roller gear.