Printing imposition, also known as CTP imposition, is to assemble small-page documents into a large version for on-machine printing.
① Overprinting. Overlay printing is the front and back printing. Two sets of PS plates are needed. After printing one side, the reverse paper is replaced with another set of PS plates to print the other side. The overlay printing paper only needs one bite.
② reflexive printing. Only one set of PS versions is needed. The front and back sides of the printed matter are spliced on the left (positive) and right (reverse) sides of the same PS version. After one side is printed, flip the paper horizontally (left and right) to print the other side. Change the PS version and various parameters on the printing press. Self-reflective printing paper only needs one bite.
③ Anti-bite printing. Anti-bite printing is also called heaven and earth turning to print. Only one set of PS versions is needed. The front and back of the printed matter are spelled on the same PS version with the sky (positive) and the earth reversed). After one side is printed, turn the paper vertically (heaven and earth) to print On the other hand, there is no need to replace the PS version and various parameters on the printing press at this time. Two bites are required to print the paper with the reverse bite, and the values of the two bites should be equal, that is, the printed matter must be centered on the top and bottom of the paper, otherwise the paper will not be printed if it is turned over.
Terminology in imposition, head to head, foot to foot. You can use paper folding to simulate the left and right order of page numbering and design arrangement, and then design. Keep in mind that the left and the right order of the document arrangement corresponding to the page number is not the same. The order of page numbers is not consecutive, that is, p1 is not necessarily p2 on the side of p1, not necessarily p1 on the left, and p2 on the right. Now there is automatic imposition software, which can automatically make small pages into large versions according to the binding method.
①Bite line. During the entire process of conveying paper on the printing press, the position where the gripper bites are not inked, and this position is called the bite. In order to facilitate printing and the inspection of blue paper, we need to add an undercut line. The position of adding the undercut line is 10mm above the edge of the paper (ground), and the line is added on the left and right sides of the paper. The length and thickness of the line are normally 20mm0.2mm. can also be customized
② Pull the gauge line. The instrument used by the printing press to balance the paper, we call a paper gauge; in order to facilitate printing and post-process inspection, we will add a line on the edge of the paper when imposing, this line is called a pull gauge line, add a pull gauge line The position of the paper is 100mm or 150mm from the right side of the paper (the right side of the front side, the left side of the backside), and the printing will balance the position of the paper according to this line.
③ Crosshairs. In order to facilitate the folding of the subsequent process, we will add a cross in the corresponding position during the imposition, and different folding methods are added in different positions.