The choice of paper roll type is determined by the machine type, speed, degree of automation, paper receiving method, etc. Sort by the number of paper rolls 1) Single paper roll, one paper feeder can only load one paper roll. After the paper roll is used up, stop the second paper roll, pick up the paper manually after loading the paper roll, and then start printing. This kind of paper feeder needs to stop the machine every time a paper roll is used up, so it is generally used on machines with low speed. It is generally no longer used on modern gravure printing machines. 2) Double paper roll, two paper rolls can be loaded on one feeder at the same time. Among them, the double paper roll can be divided into two paper arm rotating paper changing methods. The upper paper roll is used first. During use, the lower paper roll is packed and ready for use. After the first paper roll is used up, it can be stopped manually to pick up paper or automatically without stopping. After the paper is connected, the second paper roll is transferred to the working position for use, and the original first paper loading mechanism is transferred to the paper loading position, the old paper roll is unloaded, and then a new paper roll is used. Two paper rolls on one fixed frame, and two paper rolls on one fixed frame. The support of this paper feeder cannot be rotated. After a paper roll is used up and the paper tape is connected, the remaining paper core is hung down with a lifting device, and then the new paper roll is lifted and installed. The paper receiving of this paper feeder can also have automatic paper receiving and manual paper receiving. Two independent paper rolls, two independent paper rolls. Generally used in double-roller and double-roller web offset presses. That is, two paper tapes are printed simultaneously, and two paper rolls are used at the same time. After the two paper rolls are used up, the two paper rolls are loaded at the same time after stopping. If it is used on a single-paper web offset press, one paper roll is used, and the other paper roll can be used as a spare, to reduce the time of downtime and increase the utilization rate of the machine. 3) Three paper rolls. When one paper roll is about to run out, the paper holder rotates by an angle so that the second paper roll enters the automatic paper receiving position. When the first paper roll is used to the specified size, it will automatically pick up the paper. After receiving the paper, it will be rotated by an angle. The second paper roll will turn to the correct use position, and the first paper roll arm will turn to the position of loading and unloading. Remove the used paper core and install a paper roll for future use. Paper roll clamping method The method of loading and clamping paper rolls 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. Paper holder with mandrel Taking the domestic JJ201 web printing machine as an example, the paper mandrel is a long optical axis with a thread at one end, and it is inserted into the air of the paper roll to be printed. The top is fixed on the shaft according to the width of the paper roll, and Tighten the top. 2. Paper holder without mandrel The mandrel-free paper holder uses two tapered heads to hold the material roll, adjust the lead screw to move the top with the bracket, and clamp the material roll from both sides. Replacing the material roll Web-fed rotary printing presses are high-speed printing presses. Generally, a paper roll can be printed in 15-20 minutes. If the roll is changed during shutdown, the production efficiency of the machine will be greatly reduced. At the same time, the normal is destroyed during the shutdown and startup The printing work status caused inconsistent printing quality and even waste products. The loss of paper tape is as much as 20-30 meters each time, so it is best to replace the material roll and connect the paper tape during the operation of the machine. The consumption can be reduced to 3-5 meters. 1. High-speed splicing The high-speed automatic material receiving device refers to an automatic material receiving device that completes the bonding material roll and replaces the material roll in the state of the material roll during the operation of the machine at full speed or slightly reduced speed. The following process actions are completed during the entire process of replacing the material coil: When the diameter of the reel in use is reduced to a certain extent, the monitoring device sends out the first feeding signal, the host machine slows down or does not slow down, and the driving device of the reel rack 1 loads the new and old rolls to the receiving Position, so that the material roll of the old material roll that is being conveyed passes near the circumferential surface of the new material roll, and the material holding brush equipped with a material receiving brush and a material cutting knife swing down to the material receiving position, which is the material receiving be ready. The acceleration of the new roll by the drive of the roll is that the surface speed of the new roll is equal to the linear speed of the original roll being printed. When the old material roll is consumed to the predetermined minimum size, the monitoring device sends a second material receiving signal, and the paper receiving brush immediately presses the running material roll to the surface of the new material roll. Connect the two paper tapes together, the new material roll material belt is forwarded immediately, the new material roll begins to unfold, after about 1 second, the cutter on the receiving rack cuts the old material roll, the new and old material roll The process is completed. The roll holder rotates to the normal working position, and the roll is normally unfolded for feeding. During this period, the old roll can be unloaded and the next new roll can be installed. 2. Zero speed feeding The so-called zero-speed connection means that the material roll is bonded at a static state, and the machine is still running at a normal high speed. During this period, the material roll storage device of the feeder-the stocker supplies the printing machine with conveying material. band. The characteristic of zero-speed feeding is a storage device composed of a series of guide rods used for the storage belt, and a fixed and movable storage rack. The movable stick storage rack of the stocker is lowered to the lowest position, and then the material reel is put on, and the movable storage rack is raised to the working position, so that the required material reel is put on 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. The required material roll is taken out of the storage device, and the movable rack is lowered accordingly. And keep the material roll tension unchanged. After the bonding is completed, the active storage rack is raised to the working position, at this time, the material roll is accelerated to the open working speed by the tension of the material roll belt. 3. Cutting when changing the roll The cutting of the replacement roll is after the monitor sends out the signal for the second time. This is the state where the old roll is close to being used up, and the new roll has been accelerated to the speed required by the printing press for normal printing. At this time, the axis of the cutter is driven by the cylinder to rotate a certain angle to complete the cutting of the old material roll. Pet shelter and rest area,pet house bed for cat and dog,indoor pet house bed Ningbo XISXI E-commerce Co., Ltd , https://www.petspetsaccessories.com