Introduction to the basic knowledge of the roll paper roll paper machine
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The choice of paper roll type is determined by the type of machine, speed, degree of automation, paper picking method, and so on.
Classified by paper roll number
1) Single paper roll, one paper machine can only have one paper roll. After the paper roll is used up, stop the second paper roll, manually pick up the paper after the paper roll, and then start printing. This type of paper machine has to stop the machine every time it runs out of paper, so it is generally used on machines that are not too fast. It is generally no longer used on modern gravure presses.
2) Double paper rolls, one paper roll can be simultaneously loaded on one paper machine. The double paper roll can be divided into two paper arm rotary paper changing modes, and one of the upper paper rolls is used first, and the following paper roll is ready for use during use. After the first paper roll is used up, you can stop the manual paper pick-up or automatically stop the paper without stopping the machine. After the paper is connected, the second paper roll is transferred to the working position. The original paper feeding mechanism is turned to the paper feeding position, the old paper roll is removed, and a new paper roll is used for use. Two paper rolls on one holder and two paper rolls on one holder. The support of the paper feeder cannot be rotated. After a paper roll is used, the used paper core is suspended by the lifting device, and the new paper roll is lifted and installed. The paper feed of this paper feeder can also be automatic paper picking and manual paper picking. Two separate paper rolls, two separate paper rolls. Generally used for double-paper double-paper roll paper offset printing. That is, two paper strips are printed at the same time, and two paper rolls are used at the same time. After the two paper rolls are used up, the two paper rolls are stopped at the same time. If it is used on a single paper web offset press, one paper roll can be used, and the other paper roll can be used as a spare to reduce the time of paper stoppage and improve machine utilization.
3) Three rolls of paper, when a roll of paper is about to run out, the paper frame is rotated by an angle to bring the second roll into the automatic paper feed position. When the first paper roll is used to the specified size, the paper is automatically picked up, the paper is rotated by an angle, the second paper roll is transferred to the correct use position, and the first paper roll arm is transferred to the loading and unloading paper roll position, unloading Use the used paper core and install a paper roll for later use.
Paper roll clamping method
The method of loading the roll paper roll can be divided into two types: non-mandrel loading and mandrel loading. According to the degree of automation, it can be divided into manual and electric loading.
1. Mandrel paper holder
Taking the domestic JJ201 web press as an example, the paper core shaft is a threaded long optical axis, which is inserted into the air core of the paper roll to be printed, and the top is fixed on the shaft according to the width of the paper roll, and Clamp the top.
2. Coreless paper holder
The non-core paper holder is a two-cone head clamping roll, which is clamped from both sides by adjusting the lead screw with the tip moving axially along with the bracket.
Roll paper rotary printing is a high-speed printing machine. Generally, a paper roll can be printed in 15-20 minutes. If the roll is replaced, the production efficiency will be greatly reduced, and the machine will be destroyed during the machine stop and start. The printing work status, resulting in inconsistent print quality, even waste products, each loss of paper tape as much as 20-30 meters, so it is best to replace the roll during the operation of the machine, pick up the tape, at this time the tape The consumption can be reduced to 3-5 meters.
1. High speed receiving
The high-speed automatic feeding device refers to the automatic feeding device for binding the material roll and replacing the material roll in the running state of the machine at full speed or slightly decreasing speed. The entire process of changing the material roll process completes the following process actions:
When the diameter of the coil being used is reduced to a certain extent, the first receiving signal is sent by the monitoring device, the main engine slightly slows down or does not slow down, and the driving device of the reel 1 loads the new and old materials into the receiving material. The position is such that the roll of the old roll that is being continuously conveyed passes through the circumferential surface of the new roll, and the platen brush for the receiving material and the receiving frame of the cutting knife are hem to the receiving position for receiving the material. be prepared.
The acceleration of the new roll by the drive of the roll is such that the surface speed of the new roll is equal to the line speed of the original roll being printed.
When the old roll is consumed to the predetermined minimum size, the monitoring device sends a second receiving signal, and the paper picking brush immediately presses the running roll against the surface of the new roll, and the new roll of paper has a double-sided tape on the head. The two paper strips are connected together, the new material web reel is transported forward, and the new material roll begins to unfold. After about 1 second, the cutter on the receiving rack cuts off the old material roll, and the new and old material rolls are connected. The material process is completed.
The roll holder is swung to the normal working position and the roll is normally unloaded, during which time the old roll can be removed and the next new roll can be installed.
2. Zero speed receiving
The so-called zero-speed material feeding means that the material roll is finished in a static state, and the machine is still operating at a normal high speed. During this period, the material is supplied from the material storage device of the feeder to the printing machine. band. The zero-speed material is characterized by a hopper consisting of a series of guide rods for the storage belt, fixed and movable storage racks.
The movable stick storage rack of the hopper is lowered to the lowest position, and then the material reel is put and the movable storage rack is lifted to the working position, so that the required material reel is put and stored, and the machine runs normally. During the operation of the machine, the preparation of the new material roll is completed. During this process, the machine runs normally, and the required material roll is extracted with the hopper, and the movable frame is correspondingly lowered. And keep the tension of the coil unchanged. After the bonding is completed, the movable storage rack is raised to the working position, and at this time, the tension of the material is accelerated to the opening working speed.
3. Cutting when changing the roll
The cutting of the replacement roll is after the second signal from the monitor, which is the state in which the old roll is nearly exhausted, and the new roll has been accelerated to the speed required for normal printing of the press. At this time, the axis of the cutter is rotated by a certain angle under the driving of the cylinder to complete the cutting work of the old coil.