Offset press paperboard analysis (2)

It can be seen that there are at most three sheets of paper under the double sheet detector (in the normal state) if the sheet width is 720 mm. The graph is represented as:

(Figure 1.10b)

There are up to four sheets of paper under the double sheet detector. As a result, the paper web changes, and the number of sheets under the double-sheet detector also changes.
The double-sheet detector works by converting paper thickness into angle magnification.

As shown in Figure 1.11, as the thickness of the paper increases, the lower roller gradually rises and comes into contact with the upper roller. When the two are in contact, the upper roller rotates. After the roller is turned, the pin above the roller also rotates with it, which pushes the micro switch and sends out a double-sheet detection signal.

The adjustment is as follows: After the machine works normally, the pinch roller has been pressed down. At this time, the paper under the double sheet detector is the most. At this time, adjust the screws on the double sheet controller to make the lamp light, then put a sheet of paper under the detection wheel that is the same as the thickness to be printed, adjust the double sheet controller, make the lamp just off, and record the number of turns of the screw. Reverse half of its laps.

(Figure 1.11)

(4). The function of the paper feeding belt and the feeding paper conveys the paper from the feeder part to the part of the rules. The paper feeding belt is in contact with the paper receiving roller by friction, and transmits the paper by friction. Therefore, it is necessary to ensure the conditions for friction of the paper feeding belt during normal operation. There are three points to note when it comes to the transport of paper tapes: a. The transport tape should be tightly wrapped on the drive roller, and should not be put on top; b. The tape should be in contact with the part of the drive roller, and should not be connected with it. Smooth part contact; c. The surface of the conveyor belt should have a large friction coefficient.

(5). Pressure roller The function of the pressure roller on the paper feeding board is to make sure the paper and the paper feeding belt are reliably contacted with each other to generate enough friction to move the paper forward. The adjustment of the platen roller is basically the same as the adjustment of the two rollers on the take-up roller. There are two points that must be noted in the adjustment process of the platen roller: One is the principle of symmetry: The second is the convergence relationship between the papers, that is, the paper feeding step should be considered. The pressure roller on the take-up roller leaves the transfer station and the transfer roller on the transfer plate should press against the paper.

(6). Brush wheel The role of the brush wheel is to prevent the paper from rebounding after it is positioned, so it is generally placed at the end of the paper (or the second half).

(7). Platen frame The platen frame mainly serves to support other paper pressing or paper stoppers such as a platen roller. The position of the press frame is generally designed and cannot be adjusted during use.

(8). The function of the paper-feeding paperboard is to support the tape to convey the paper. The requirements for the transport of paperboard must be such that there are no factors that can destroy the frictional drive, ie the surface must be smooth and smooth. The direct contact with the paper conveying board is a paper feeding belt, so it is very important for the wear of the paper feeding belt.

The warpage of the paperboard directly affects the paper transport. If the surface is bad, it will scratch the surface of the paper. Another function of the paperboard is that it can be used to eliminate static electricity. Foreign equipment is generally used steel paperboard has a certain relationship with this.

(9). The suction hole has a suction hole in the middle of the paper feeding board. When the paper feeding part is in failure, it sucks the paper on the paper feeding board to prevent it from sliding due to inertia.