How to Avoid the Defects of Paper in Print on Demand (I)

Even for those who have rich experience in printing and binding, they may feel very tricky when they first start digital printing. For example, digital printing and offset printing are two completely different processes, but the paper they use is indeed the same. Therefore, people also expect that the paper can be processed in the same way, resulting in unsatisfactory results. Sometimes, it is not until the post-printing stage that the paper problem is found. The loss is very large.

The digital printing process consists of various complicated technologies, and the paper issue mentioned in this paper is just one of the common problems. The best way to avoid the problem is to learn as much as possible about the relevant knowledge, communicate with other users of similar products, and reserve the amount of information so that they are not needed.

Communicating with equipment manufacturers is also very important, and many suppliers will provide a list of paper samples labeled “approved” or “certified” to identify which papers can be used for their equipment. Ideally, these lists can accurately reflect the communication and test results between paper mills and equipment manufacturers.

Digital printing companies, though not capable of confessing these lists, are a good start. Any traditional printing company involved in digital printing should not take it for granted that the paper they used in the past can be successfully processed by a digital printer. Similarly, for every new digital device installed, a lot of experimentation should be done on the corresponding paper to make sure it works properly.

Lack of regulation

If you are operating a digital press, you will find that there are few parameters that can be adjusted on the digital press. Most of them have been set by the manufacturer. Those who have experience in the operation of traditional presses may not be accustomed to this point. . Running a problematic paper requires more attention to external factors. Once the operation has started, it is very difficult to correct the problem, so it is very important to avoid the problem in the preparation of printing.

At present, in the high-speed digital printing process, the three paper factors are mainly emphasized. This is different from the offset printing process. These three factors have a great influence on the subsequent binding process.

Winding journey

In fact, all digital presses have undergone a tortuous process in paper applications. Most of them do not use grippers or other mechanical equipment to complete the paper feed. This makes the direction of silk paper become Important. Most digital presses pick up paper in 11- or 12-inch directions, or print only 1- or 2-page prints. The proper orientation of the strand is perpendicular to the direction of the paper, which means that for 81⁄2 x 11-inch paper, it is a filament. For 11 × 17 inch paper, it is a short silk direction, otherwise it will cause unnecessary losses, such as paper jams and overprinting problems.

However, this has a great conflict with the binding process. For example, if you want to process an 81⁄2 x 11-inch paper, it is best to print along the direction of the filament, and for the folding process, It is hoped that the short-term direction. If thicker paper is used, the problem between the two departments will further deteriorate.

Here's a more complicated example: A 51⁄2×81⁄2 size paper is printed on an 8 or 4 open machine and then glued. Appropriate silk orientation is used for printing, and when the book is bound, the page ripples occur. This is because the silk of the paper does not coincide with the direction of the spine. Therefore, the direction of the paper strands should be carefully determined before production to minimize the quality loss during the post-processing.