“Cushioning method” quickly eliminates the wrinkle of carbonless paper printing
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
Carbonless copy paper, also known as pressure sensitive recording paper, is a commonly used printing material for multi-reports, bills, computer terminals, etc. It is easy to use and fast, and is popular among users. It is widely used in aviation, postal, telecommunications, commerce and Other service industries. Since the carbonless paper material is light and thin, the stiffness is relatively poor. When the moisture content of the base paper is improperly controlled, the paper edge is prone to curling or wave deformation after unpacking, so that the edge of the paper is easily wrinkled when printed by an offset printing machine. Not only the printing quality of the product does not meet the user's use requirements, but also causes certain obstacles to the normal printing of the machine.
1. Analysis of printing wrinkle failure
Our company used the J2205 type two-color offset printing machine to print the upper and the neutral carbonless paper (the size of the four open 59.5 × 44.3cm specifications), and when printing 45 grams of yellow lower carbonless paper, the paper Wrinkling faults frequently occur on both sides, causing quality defects in the deformation of the table layout and the lack of strokes in the text, which also affects the accuracy of the sleeve product and does not meet the quality requirements of the use. After this problem occurs, although the operator has adopted the light printing pressure, checking the flatness of the blanket, the uniformity of the elastic cloth, and repeatedly adjusting the pressure of the roller biting paper, it does not help, and the printing wrinkling phenomenon cannot be eliminated. The cut semi-finished base paper can not be returned or replaced, and the customer is anxious to urge the goods, the situation is more difficult, I do not know how to be good. In this regard, the author observed and checked through the scene, found that this joint printing is prone to wrinkled carbonless paper, the edge has curl and deformation, in addition, the left and right sides of the paper do not have corresponding roller teeth, so in the printing process With the rapid rotation of the drum, the two sides of the paper fall back because they are not bitten by the teeth, so that the left and right sides of the paper and the middle paper edge do not maintain a straight line and synchronous rolling, so that the squeezing action of the drum during the embossing is easy to make The uneven paper produces a number of wrinkles on both sides of the tip. After analyzing the reason, the author immediately flashes a solution to the problem, adding cardboard padding to the left and right sides of the printed sheet, using the elasticity of the blanket, through the liner of the cardboard. Tightening the paper surface to eliminate the wrinkles of printing.
2. Apply "padding method" to quickly eliminate printing wrinkles
The so-called "padding method" means that two cardboard strips of appropriate thickness and width are respectively placed on the corresponding positions of the impression cylinder and the two sides of the printing sheet. The specification for the printed sheet is 44.3×59.5cm. In order to eliminate the phenomenon of printing wrinkle quality failure, the author has glued a white strip of appropriate width and thickness to each side of the printed sheet (59.5cm direction). The paper surface is embossed, so that the wrinkling of the printed sheet is avoided faster and better, which not only realizes normal production, but also ensures the quality of the product. The specific method is: take a 250-gram thick whiteboard paper, cut out two cardboards with a width of 5mm and a length of 430mm, and then use a double-sided adhesive of 5×430mm size, respectively, to align one side of the two cardboards. On, and remove a layer of wax paper on the surface, then put a large four-open paper on the cardboard, press the normal printing position of the machine to let the paper enter the impression cylinder, and jog the machine to the appropriate position to separate the two cardboards. One by one is pasted on both sides of the impression cylinder and corresponds to the left and right sides of the printed sheet. When pasting, the edges of the two 430mm long cardboards are required, and the edge of the corresponding paper edge of the printed sheet is about 13mm, that is, the length of the two cardboard strips. The edge can be aligned with the end of the printed sheet, so that the paper on the left and right sides of the sheet first touches the surface of the two cardboard strips when the cylinder is embossed, and then the hard cardboard strip forces the blanket to sink, making the loose paper surface In the tensile deformation, the tension is obtained, that is, the machine is pressed against the edges of the left and right sides of the paper in the embossing state, thereby playing the role of tensioning the paper surface, thereby better eliminating the wrinkling of the paper printing. . It is worth noting here that the thin paper with uneven printing surface is coated with cardboard strips on both sides of the impression cylinder (corresponding to the two sides of the printing sheet). The old blanket should be replaced with a new one to avoid pushing out the good blanket. The traces of the road caused two light traces when printing the flat net or the solid version. In addition, after the printing of the flat paper with poor flatness is completed, the two cardboards on the impression cylinder should be peeled off, and the glue remaining on the roller should be cleaned with gasoline to avoid the embossing of a good blanket. Deformation of the depression. If the paper edge wave deformation is particularly strong, you can increase the thickness of the paperboard strip (such as using a layer of whiteboard paper), and then cut the corresponding area and thickness of the backing paper of the cardboard strip. In this way, when the embossing uses the "floating" state on both sides of the blanket, more expansion and contraction space can be formed, so that the tension obtained by the printing sheet can be further increased. The printed sheet is not prone to cracking, and the damage to the blanket is also light, which can better eliminate the wrinkling of the paper.
3. Technical tips to reduce or prevent printing wrinkles
The production process practice shows that the unevenness of printing is the main reason for printing wrinkles. However, the machine is also prone to cause printing wrinkles, such as the structural characteristics, position, pressure of the teeth, the characteristics of the lining, the flatness of the drum and the printing pressure, etc., which may also cause the printing paper to appear. Wrinkles are sick. Therefore, from the technical point of view of preventing printing wrinkles, in the process of embossing the printed sheet by the biting paper, the printing sheet should not be slightly slipped or deformed after being pressed by the printing force, especially biting. The two paper corners on the edge of the paper, if there is a backward movement, it is very easy to produce printing wrinkles. Therefore, the paper angles on both sides of the left and right sides of the printed sheet should correspond to the teeth. It is printing thin paper, the printed sheet is not bitten by the bite paper, and the probability of printing wrinkles is even higher. Secondly, when positioning the printed sheets, try to make the paper-biting teeth bite more and more paper edges, and the pressure of each biting should be adjusted enough and kept even. Third, the lining should be kept flat and firm, and the coefficient of compression deformation should be minimized. Fourth, under the premise of maintaining the appropriate definition of the printing layout, printing with the lightest printing pressure, through these technical measures, can minimize and avoid the occurrence of printing wrinkle failure.
After reasonable adjustment of the machine, the paper with a more severely deformed paper surface still has wrinkle failure phenomenon, and only the cardboard strip is applied to both sides of the impression cylinder to achieve the tightening of the paper surface in the embossing, thereby eliminating The purpose of printing wrinkles. Although this practice is contrary to the printing of the "three flats" theory, successful practice has shown the feasibility and practicality of this method. This is because the blanket is very elastic, and the two cardboard strips that are slightly above the surface of the impression cylinder are forced to stretch the partially loosened paper side by embossing. This does not give the printing pressure and layout. Register and ink layer transfer caused too much adverse effect. Since the author created this method more than 10 years ago, after the success of the small offset printing test, the J2108B type off-color offset printing machine has been tested for wrinkle failure, and the same good solution has been achieved, which greatly reduces the paper. Waste phenomenon, improve the qualified rate of products. This time, our company used J2205 type two-color offset printing machine to print carbonless paper. After the first obvious wrinkle failure, the author applied this solution to quickly eliminate paper printing wrinkle failure, which also achieved better elimination. The problem of wrinkle-free printing on carbonless paper is satisfactory.