Riso V8000 Series, Technical Manual

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CHAPTER 4. FIRST PAPER FEED SECTION
Feed tray button
P0432
Upper limit sensor B Upper limit sensor A Pressure adjust lever
Paper feed pressure
sensor
2. Paper Feed Tray Elevation Mechanism
The paper feed tray is raised automatically at the start of printing and is lowered when there is no more
paper in the paper tray and the paper detection sensor does not detect reflected light.
The paper feed tray is also lowered if the feed tray button is pressed during print standby.
The paper feed tray is raised and lowered by the elevator motor. The upper stop position is detected by
the elevator upper limit sensor, and the lower stop position is detected by the elevator lower limit sensor.
The scraper pressure is varied by switching the pressure adjust lever between “Standard” and “Card.”
(Spring pressure adjustment)
The paper feed pressure sensor detects the lever setting.
Either of the two elevator upper limit sensors (A and B) are used, as determined by the paper feed
pressure sensor.
Positioned on the same bracket as the elevator lower limit sensors, paper volume det. sensors A and B
determine the amount of paper remaining based on the paper feed tray position.
Paper volume percentages are checked in 100%, 75%, 50%, and 25% by above sensors, but when
displaying the percentages on the panel, they are converted to 100%, 59%, 30%, and 10%.
If a foreign object is trapped in the paper feed section during raising or lowering of the paper feed tray, the
elevator is immediately halted by the paper feed tray safety switch.
An air pump mechanism is incorporated to prevent poor printing due to paper dust .
3. First Paper Feed Mechanism
The paper feed through the first and second paper feed sections is checked by the first paper sensor,
second paper sensor, and multiple paper feed sensor. The first paper sensor is located before the
second paper feed roller, while the second paper sensor and multiple paper feed sensor are located after
the second paper feed roller.
Paper is fed through the first paper feed section by the rotation of the scraper and pickup roller. The drive
side of the paper feed clutch rotates continuously while the main motor rotates, but the actual rotation of
the scraper and pickup roller is controlled by switching the paper feed clutch on and off.
The paper feed clutch is switched on at an angle of 150° from the paper drum position T.
The paper feed clutch is switched off when the paper drum has rotated 18° after paper has been detected
by the first paper sensor.
The leading edge of the paper strikes the second paper feed roller here, and stops with the paper flexed.
A one-way core is fitted to the scraper and pickup roller so that they spin, keeping the first paper feed
section from acting as a brake once the paper has been transferred beyond the second paper feed
section.