How to reduce the scrap rate in CTP platemaking

In recent years, "CTP" technology has become a hot topic in major print media. Domestically powerful companies have also introduced CTP plate making equipment to establish a corporate image and improve their competitiveness. However, having the most expensive and most advanced equipment is just a good reputation. For companies that own CTP plate making equipment, the most practical thing is to reduce costs and create maximum profits.

The company's Xi'an Coal Airline Map Printing and Printing Company introduced the Heidelberg CTP plate making equipment in October 2001. From equipment installation and commissioning to scale production, the author had the honor of having been on the battle line, deeply impressed by the fact that Production cost is an effective way to use CTP equipment to maximize profits.

For an independent accounting platemaking shop, the cost of a CTP plate-making process is much higher than that of the film-making process, if only from the perspective of material use. The process of our company's film making process is: film output→printing and printing→dyeing and proofing; the CTP plate making process is: digital proofing→patching→changing→CTP output. With CTP version 100 yuan / Zhang, film 53 yuan / m 2, renewable PS version of 20 yuan / pair open, high light photo paper is 6 yuan / m 2 calculation, with a set of large four-color live (87cm x 57cm) For example, the cumulative cost of consumables for the film process is: 0.87 x 0.57 x 4 x 53 (film) + 4 x 20 (plate) = 185.13 yuan; and the cost of the CTP process is: 0.87 x 0.57 x 6 (digital proof) + 100 ×4 (plate material) = 402.98 yuan.

From the above data, it can be seen that the cost of the CTP plate making process is more than 2 times higher than that of the film plate making process. The main reason for this result is the high price of the CTP plate material. At the present stage, the CTP plate used by our company (Kodak Bolilite's plate) still relies on imports. Although we can not reduce the cost in terms of price, we can minimize the waste disposal rate in each production and fully reflect the CTP plate making. The advantage of the network is to attract customers with advantages such as high copying precision, rich image layers, and shorter operating time, which creates profits for the entire company (in fact, if the cost of the integrated printing shop plate, the CTP plate making process and the film making process The cost is almost equivalent).

In the past year, the author has accumulated some methods to reduce the scrapping rate and make up the version. I would like to share it with my colleagues.

1. Keep the PS version clean and smooth

The Topsetter 102 is an external drum type plate making machine, which requires a particularly high degree of cleanliness and flatness of the plate material, especially when it comes to the work of the frequency modulation network. In the initial period of CTP use, the gradation hopping phenomenon often occurs on the flat screen when working out the frequency adjustment network. (A small area with a deeper level is visible to the naked eye. Observable under the magnifying glass is that the network is significantly denser than the surrounding area.) . Excluding the cause of the document itself, after repeated experiments and analysis, it was finally found that dust or irregularities on the plate resulted in uneven heat absorption during exposure, resulting in uneven thermal cross-linking reactions.

For these reasons, we require that the operator must wear clean work gloves when loading CTP plates, and then pull the vertical printing materials from the plate directly into the entrance of the Topsetter 102, and must avoid folding during the transport process. Edition (My company uses Kodak PolyLight's Graphics 0770 × 1030 plate, thickness of only 0.3mm, very easy to fold version).

2. Addition and deletion of content on the plate

Although the customer's sample proofs for digital proofing have been signed and used by the CTP system before outputting the plates, and the quality inspectors have also conducted strict proofreading, there are still problems with the contents of the individual printed materials inevitably after the plates have been printed. For example, sometimes there is a lack of one or two field content (such as lines, punctuation marks, etc.) with a dot percentage of 100%. If there is no color fit, the plate will not need to be re-used. The following method can be used to make up: First wipe off the protective glue on the printing plate, mark it on the printing plate with a squeegee (use a moderate force), and then put on the ink, and then wipe on the protective glue (but this edition cannot exceed 3,000 prints).

If there is any extra content on the plate, if it does not involve color fitting, it can be repaired with Xingguang PS plate version, wiped clean with water, and then wipe with peach gum.

3. Dirty processing of printing plates in the publishing process

The plate used by Topsetter 102 is a thermal CTP plate. When the temperature exceeds a critical value during exposure, a cross-linking reaction occurs in the image and forms a latent image. During development, this portion is insoluble in the developer while the unexposed blank portion is The resin layer was dissolved in the developer because no cross-linking reaction occurred. After a certain period of time after a certain amount of plate material has been developed, a portion of the resin layer in the developer solution will form a lot of floc and adhere to the finished plate material. If it is not treated, it will cause the printing to be dirty. The solution is: 1 often cleaning, replace the filter core of the processor; 2 before booting the printing plate, thoroughly clean the developing machine, especially the rollers in the developing machine; 3 for floating on the plate, available Clean water first wipe off the protective rubber, use a small brush, dipped in a little developer liquid, and gently wipe it with clean water. Repeatedly, it can be removed (note that the dwell time on the plate must be short, otherwise it will Injury the small outlets around, and then wipe the protective gel.

4. Insufficient processing of plate development

When the developer (Kodak Premium CTP Positive Developer) is fatigued, for the Kodak Polyurray Graphics 0770×1030 plate, the layout of the blank part will be blue and the upper machine belt will be dirty. For this type of media, secondary development can be carried out to meet the printing quality requirements (but should pay attention to the development conditions, we usually adjust the development time, brush speed to twice the original, and must detect changes in the printing plate Internet point ).

In order to maximize the use of developer, while ensuring the quality of the printing plate, according to the fatigue of the developer, we can make up for the following two methods: 1 adjust the plate calibration curve value; 2 increase the development time or the development temperature or Increase brush speed.

All of the above methods can effectively reduce the scrapping rate in CTP plate making, thus reducing the cost of CTP plate making.

Source: Comin Media