In recent years, "CTP" technology has become a hotspot in the discussion of major print media, and domestic powerful companies have also introduced CTP plate-making equipment to establish their corporate image and improve their competitiveness. However, having the most expensive and advanced equipment is just a reputation. For companies with CTP plate-making equipment, the most practical thing is to reduce costs and create maximum profits.
The Xi’an Coal Airline Map Printing Company where the author is located introduced the CTP plate-making equipment of Heidelberg in October 2001. From equipment installation and trial operation to scale production, the author is fortunate to have been fighting on the front line and deeply felt that the reduction Production cost is the effective way to get the most profit by using CTP equipment.
For an independently-accounted plate-making workshop, if only from the perspective of material use, the cost of the CTP plate-making process is much higher than the film plate-making process. The process of our company's film plate making is: film output → printing → proofing → batch sample; CTP plate making process is: digital proofing → batch proofing → modification → CTP plate output. Taking the CTP version as 100 yuan / sheet, the film as 53 yuan / m2, the regenerated PS version as 20 yuan / sheet, and the glossy photo paper as 6 yuan / m2. Take a set of large folio four-color live parts (87cm × 57cm) as an example The cumulative cost of consumables in the film process is: 0.87 × 0.57 × 4 × 53 (film) + 4 × 20 (plate) = 185.13 yuan; and the cost of the CTP process is: 0.87 × 0.57 × 6 (digital proofs) + 100 × 4 (Plate) = 402.98 yuan.
It can be seen from the above data that the cost of the CTP plate-making process is more than twice that of the film plate-making process, and the main reason for this result is the higher price of the CTP plate material. At this stage, the CTP plates used by our company (Kodak Polychrome plates) still rely on imports. Although the price cannot be reduced, we can minimize the waste plate rate in each production and fully reflect the CTP plate making Advantages of high-precision dot copying, richer image layers, and shorter operating time to attract customers and create profits for the entire company (in fact, if the cost of plate materials in the printing workshop is integrated, the CTP plate making process and the film plate making process The cost is almost the same).
The author has accumulated some methods to reduce the scrapped version rate and supplement the version in the production for more than a year, and is willing to share with my colleagues.
1. Keep the PS version clean and smooth
Topsetter 102 is an external drum direct plate-making machine, which has particularly high requirements on the cleanliness and flatness of the plate material, especially when it comes to the live parts of the FM network. In the early days of CTP, when the live parts of the FM network are out, there is often a level jump phenomenon at the flat screen (a small area with a deep level is seen with the naked eye, and the dots are obviously denser than the surrounding area under the magnifying glass) . After excluding the cause of the document itself, after repeated experiments and analysis, it was finally found that the dust on the plate or unevenness caused uneven heat absorption during exposure and uneven thermal crosslinking reaction.
For the above reasons, we stipulate that the operator must wear clean work gloves when installing the CTP printing plate, draw the publication material vertically from the plate box, and place it directly at the inlet of the Topsetter102, and must prevent folding during transportation (My company uses Kodak Polygraphics Graphics0770 × 1030 plate material, the thickness is only 0.3mm, very easy to fold).
2. Adding and deleting content on the printing plate
Although the customer has signed and approved the digital proofs before using the CTP system to output the printing plate, and the quality inspection personnel have also conducted strict proofreading, there are still some problems in the content of individual printed products after the printing plate is completed. For example: sometimes there is one or two solid content (such as lines, punctuation marks, etc.) with a dot percentage of 100%. If there is no color registration, this printing plate does not need to be repeated. You can use the following methods to make up: First wipe off the protective glue on the printing plate, use the engraved needle to score on the printing plate (the force should be moderate), then lift the ink, and then wipe the protective glue (but the printing volume of this version cannot exceed 3000).
If there are some extra contents on the printing plate, in the case of no color matching, you can use the Starlight PS version of the revision liquid to fix it, and wipe it clean with clean water, then wipe peach glue.
3. Handling of the dirty printing plate during the publishing process
The plate material used by Topsetter 102 is a heat-sensitive CTP plate. When the temperature exceeds the critical value during exposure, a cross-linking reaction occurs in the graphic part to form a latent image. During development, this part is insoluble in the developer and the resin in the unexposed blank part The layer is soluble in the developer because no crosslinking reaction has occurred. After a period of time and a certain number of plates are developed, some resin layers in the developer will form a lot of flocs, which will adhere to the finished plates. If left untreated, it will cause smearing during printing. The solution is: â‘ often clean and replace the filter core of the developing machine; â‘¡ thoroughly clean the developing machine, especially the rollers in the developing machine, before starting the printing plate; â‘¢ for the dirty on the printing plate, available First wipe off the protective glue with clean water, use a small brush to dip a little of the developer solution in the floating spot, and wipe it quickly with clean water. Repeat it many times to remove it (note that the stay time of the original solution on the printing plate must be short, otherwise it will Hurt the small dots around), then wipe the protective glue.
4. Insufficient handling of printing plate development
When the developer (KodakPremiumCTPPositiveDeveloper) is fatigued, for the Kodak Polyplastic Graphics0770 × 1030 plate, the blank part of the layout will be bluish and dirty on the machine. For this type of plate material, secondary development can be carried out to make it meet the print quality requirements (but attention should be paid to the development conditions, usually we adjust the development time and brush speed to twice the original, and at the same time must detect changes in the printing plate Internet point ).
In order to maximize the use of developer and ensure the quality of the printing plate, according to the fatigue of the developer, we can make up for it by the following two methods: â‘ adjust the correction curve value of the plate; â‘¡ increase the development time or development temperature or Increase brush speed.
The above several methods can effectively reduce the waste plate rate in CTP plate making, thereby reducing the cost of CTP plate making.
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