Reduction method of waste plate rate in the hottes

In recent years, "CTP" technology has become a hot topic of discussion in major print media. Domestic powerful enterprises have also introduced CTP plate making equipment to establish their corporate image and improve their competitiveness. However, owning the most expensive and advanced equipment is only a good reputation. For enterprises with CTP plate making equipment, the most practical thing is to reduce costs and create maximum profits

the author's Xi'an Coal navigation map printing company introduced the CTP plate making equipment of Heidelberg company in October 2001. From equipment installation, trial operation to large-scale production, the author has been fortunate to fight in the front line, and deeply realized that reducing production costs is the effective way to maximize profits by using CTP equipment

for the plate making workshop with independent accounting, the cost of CTP plate making process is much higher than that of film plate making process if only from the aspect of automatic numerical calculation of material use for key parameters such as friction coefficient, torque, speed, stroke, etc. The process of film plate making in our company is: film output → printing → proofing → batch proofing; CTP plate making process so that the fixture must be installed in the high and low temperature box: digital proofing → batch proofing → sample changing → CTP plate output. Based on the CTP version of 100 yuan/piece, film of 53 yuan/m2, recycled PS version of 20 yuan/folio, and high gloss photo paper of 6 yuan/m2, a set of large folio four-color live parts (87cm × 57cm) as an example, the cumulative cost of consumables for the film process is 0.87 × zero point five seven × four × 53 (film) +4 × 20 (plate) = 185.13 yuan; The cost of CTP process is 0.87 × zero point five seven × 6 (digital sample) + 100 × 4 (plate) = 402.98 yuan

from the above data, it can be seen that the cost of CTP plate making process is more than 2 times higher than that of film plate making process, and the main reason for this result is the high price of CTP plates. At this stage, CTP plates (Kodak Polaroid plates) used by our company still rely on imports. Although the price cannot be reduced, we can minimize the waste rate in each production, fully reflect the advantages of CTP plate making, and attract customers with the advantages of high point replication accuracy, richer image layers, shorter operation time and so on, Create profits for the whole company (in fact, if the plate material cost of the integrated printing workshop, the cost of CTP plate making process and film plate making process is almost the same)

the author has accumulated some methods to reduce the scrap rate and make-up in more than a year of production, and is willing to share them with colleagues

1. Keep the PS version clean and leveled

topsetter102 is an external drum direct plate making machine, which has particularly high requirements for the cleanliness and levelness of plates, especially for live parts with frequency modulation. In the early stage of CTP use, when the live parts with frequency modulation are released, the phenomenon of level jumping often occurs at the same time (what you can see with the naked eye is a small area with deep levels, and the points can be observed under the magnifying glass, which is more dense than the surrounding area). After eliminating the cause of the document itself, after repeated experimental analysis, it was finally found that the floating dust or unevenness on the plate caused uneven heat absorption and uneven thermal crosslinking reaction during exposure

for the above reasons, we stipulate that operators must wear clean work gloves when loading CTP printing plates, draw the publishing materials vertically from the plate box and put them directly at the plate inlet of topsetter102, and must prevent folding during transportation (our company uses graphics0770 of Kodak poly Light Company) × 1030 plate, only 0.3mm thick, easy to fold)

2. Addition and deletion of contents on the printing plate

although before using the CTP system to output the printing plate, the customer has signed and approved the sample of digital proofing, and the quality inspection personnel have also conducted strict proofreading, there are still inevitable problems in the contents of individual prints after the printing plate is issued. For example, sometimes the plate lacks oneortwo practical contents (such as lines, punctuation marks, etc.) with a percentage of 100%. If there is no color matching, this printing plate does not need to be re printed. The following methods can be used to make up for it: first wipe off the protective glue on the printing plate, scribe it on the printing plate with an engraving needle (the force should be moderate), then lift up the ink, and then rub on the protective glue (but the printing volume of this plate cannot exceed 3000)

if there is some redundant content on the printing plate, without involving color matching, you can repair it with starlight PS plate repair solution, wipe it with clean water, and then wipe it with peach glue

3. The treatment of floating dirt on the printing plate in the publishing process

topsetter102 is a thermal CTP plate. When the temperature exceeds the critical value during exposure, the graphic part will be crosslinked to form a latent image. During development, this part is technically insoluble in the developer, while the resin layer of the unexposed blank part will be dissolved in the developer because there is no crosslinking reaction. After a period of time and a certain amount of plate development, part of the resin layer in the developer will form many flocs, which will be attached to the finished plate. If it is not treated, it will cause dirt during printing. The solution is: ① often clean and replace the filter element of the developer; ② Thoroughly clean the developer, especially each group of rollers in the developer, before starting up and printing plates; ③ For the floating dirt on the printing plate, you can wipe off the protective glue with clean water first, use a small brush dipped in a little developer stock solution to gently trace the floating dirt, and quickly wipe it with clean water for many times (note that the stock solution must stay on the printing plate for a short time, otherwise it will hurt the surrounding small points), and then rub on the protective glue

4. Treatment of insufficient plate development

when the developer (kodakpremiumctppositivedeveloper) is tired, for Kodak poly light graphics0770 × For 1030 plate, the blank part of the plate will be blue and dirty on the machine. For this kind of plate, secondary development can be carried out to make it meet the printing 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, we must detect the change of points on the printing plate)

in order to maximize the use of the developer and ensure the quality of the printing plate, according to the fatigue degree of the developer, we can make up for it by the following two methods: ① adjust the value of the printing plate correction curve; ② Increase the development time or temperature or brush speed

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

reprinted from: keyin