Analysis of the quality problems of PS version baked version

Under the condition of high temperature heating, the photosensitive film of the positive-type PS plate is thermally modified to cause the cross-linking effect of the cresol resin between the film-forming agents, from a linear shape to a body structure, which enhances the photosensitive film that is the printing plate. Stability, corrosion resistance and mechanical strength of the text. The baked version can increase the PS plate's printing durability by 3-5 times to reach 300,000 to 500,000 prints, thereby reducing production costs and improving economic benefits. However, if improper operation in the actual production work, quality problems will occur in the baking version.
The following is an analysis of the quality problems of baking plates that we often encounter in production, so that we can better analyze and judge when there are problems in production.

1. Before roasting the plate, you should first handle the printing plate, such as cleaning the surface of the plate, correct development, etc. The following are some quality problems of the printing plate due to the unsatisfactory processing of the plate before baking.

(1) Light red after baking plate This light red color is caused by a small amount of photosensitive layer in the blank part of the printing plate, which is changed after baking. If it is treated with developer, it will not get dirty; if the light red color remains on the plate after treatment, it must be dirty. This situation can be dealt with by the decontamination agent, and then the ink inspection can be generally solved.

(2) Insufficient exposure or incomplete development Insufficient exposure or incomplete development will result in insufficient decomposition of the non-graphic part of the photosensitive resin, residue in the blank part, and the residual part is firmly adsorbed to the base during the baking process, which is difficult to remove In this way, the ink will be dirty on printing. In general, this situation can only be reprinted.

(3) Before roasting the plate, the plate pollution will cause the plate to be dirty. Before baking, the PS version must be cleaned, and the plate dust, impurities, and traces of decontamination agent should be cleaned in time and thoroughly. These dirts will be firm after baking It will be adsorbed on the plate surface and cause the printing plate to become dirty.

(4) Dirty and dirty parts are often seen in actual production, the reason is also very simple, that is, the dirty marks corroded by the decontamination agent are not washed out in time and thoroughly, and the same stains as the decontamination agent are reflected during printing. In order to prevent the appearance of such stains, be sure to use a sponge or a wet towel to thoroughly clean the detergent and then rinse it with water, then wipe the protective solution to start baking, to avoid getting dirty.

Second, we found that there are a lot of problems in the baking version of the baking protection agent, either due to improper use of the protection agent or due to the inappropriate formulation of the protection agent itself.
Let's first understand the role of applying a protective agent on the surface of the printing plate before baking. The main function of the protective agent is to protect the blank part of the printing plate during the baking process, so that the pores of the oxide film after the sealing treatment under the high temperature condition of the baking plate will not be reopened and activated again, resulting in ink absorption Dirty phenomenon.
Let's take a look at the following situations:

(1) Dirty printing plate after baking plate Dirty printing plate on PS plate is a common fault in production and is often difficult to solve. When encountering this kind of dirty problem, we should first find out the cause, and then take corresponding measures to deal with it. If this dirty plate is washed off with gasoline and there is a reddish brown plate at the bottom, it means that the development is not complete, and there is residual photosensitive agent that is baked and hardened, and the ink absorption is dirty. This kind of dirt has a solid foundation. Generally, it cannot be removed. If it is forcibly removed, the surrounding net patterns will also be damaged. This kind of dirty version can prevent recurrence only by increasing the time of printing or developing intensity. If there is no reddish brown roasted plate layer under the dirty plate, it may be that the concentration of the protective solution is low, the coating is too thin, and it does not protect the plate surface from contamination. Open, and contaminated and dirty. This dirty version will only show up after the ink is lifted or printed, which is usually not observed.

(2) Light streaks appear in the graphic part of the layout, and the ink affinity of the layout part decreases. During printing, the printing plate cannot faithfully reproduce the tone of the original, and light streaks appear. This is often caused by improper wipe protection. The streak left by the concentration of the protective agent is too high or it is not evenly wiped, it is hardened and fixed on the printing plate after baking, and it is difficult to dissolve in water, which causes no ink absorption. In this case, you can use alkaline solution that is slightly thicker than the normal developer to display again, and then neutralize with 3% concentration of phosphoric acid.

(3) Improper wiping of the protective agent on the dirty PS version of the baking plate protective agent is easy to precipitate. After being placed, the solute precipitates to the bottom of the bottle and the protective agent poured out is thin. Wiping the plate with such a protective agent will cause the protective film on the plate surface to be too thin or have glue leakage, which will cause the PS plate to become dirty. Therefore, it must be shaken evenly before use before pouring out. And when wiping the protective agent, be sure to smooth it evenly.

(4) The performance of the protective agent is not good, and the baking plate becomes dirty.
The performance of the protective agent used in the PS version of the baked version directly affects the quality of the baked version. Many manufacturers make their own preparations. It is necessary to pay attention to the proper formulation, whether the properties of the drugs used are standard, and whether the method of preparation is appropriate. No matter which part of the fault occurs, it will affect the performance of the protective agent, causing the protective agent to fail to protect. Especially when certain medicines are not available and should be replaced with less commonly used agents, special attention should be paid to the quality of the protective agent. In order to prevent the loss of the plate material, you can try it first, and don't put it into production after it is not dirty and has no problems.
(Formulation of baking solution: 1000ml of water; 50g of ammonium tetraborate (or ammonium hexaborate); 10g of 20 (or OP-10); 10ml of sodium dodecylbenzenesulfonate.)
Note that under normal circumstances, the amount of baking solution should be 20-30ml / (block version).

3. There are also some problems in the operation of the roaster.

(1) Surface scratches The high temperature in the baking machine causes the PS plate to deform and bend, and often scratches the plate during picking and delivery and causes scratches, which are dirty when printing. Slight scratches can be removed with plate cleaners or decontamination agents without damaging the graphic dots. If severe scratches occur, the damage to the photosensitive film cannot be recovered.

(2) Light brown or dark brown after baking, under normal circumstances, the photosensitive layer is reddish brown after baking. If the color is dark brown, it means that the baking temperature is too high or the baking time is too long. This version belongs to excessive baking, which makes the photosensitive layer resin have different degrees of carbonization, darken and become brittle. As a result, it will reduce the print resistance and ink affinity of the ps version.

(3) The dark green color after baking, indicating that the baking temperature is low or the time is short, the photosensitive resin has not been completely polymerized, and its stability, corrosion resistance and mechanical strength have not been maximized, and can be replenished. Bake once to achieve the best results.
(Generally, the curing point of phenolic resin is 200-300 ℃, and the recrystallization temperature of the aluminum plate is 250 ℃, so the temperature of the baking plate should generally be controlled at 200-230 ℃, and the time is preferably five minutes)

Fourth, there are many other factors that affect the quality of the baked version:

(1) The cloth wiping the protective agent is dirty and the plate surface is contaminated or the fibers of the cloth fall off the plate surface, causing staining after baking the plate. In this case, pay attention to replacing the cloth. Wiping cloth should pay attention to choose cotton fabric with long fiber, or special cloth.

(2) The glue was not wiped off in time during printing, and the water roller was not placed first after the machine was turned on, but the ink roller was dropped first, or the water roller with oil on the surface was put down without running enough water, causing a large number of Some ink. If this kind of ink is cleaned with gasoline, the surface will be clean, and it will become dirty when the machine is turned on. In this case, use a clean cloth dipped in cleaning solution or revision paste (the graphic foundation on the printing plate is already connected and very tight, so it will not be removed by revision paste). , And then use the fountain solution to wash in time, you can completely remove the dirt.

Five, also note:

(1) The baked printing plate should be thoroughly cleaned before printing on the machine, so as to avoid the phenomenon of no ink on the graphics. Because the baking solution contains emulsifiers, and has strong hydrophilic and oil resistance, if it can not be cleaned in time after baking, it is easy to accelerate the emulsification of ink, and it will also reduce the lipophilicity of the graphic basis.

(2) Under normal circumstances, the regenerated PS version is not suitable for baking, and it is easy to cause serious deformation of the printing plate and cannot be printed on the machine, resulting in a fee version.

Some of the temperature, time, dosage, etc. given above are not absolute. Different brands of baking protection liquids generally use different production processes, and they will be slightly different in use. We must first do the preliminary experimental work and obtain more accurate data before starting formal production to avoid the waste of plates and production time.

We supply different kinds of Pet Supplies products with high quality and favorable price. We're pleased to get your Dog Rope Toy Inquiry and we will reply you as soon as possible. We stick to the principle of "quality first, service first, continuous improvement and innovation to meet the customers" for the management and "zero defect, zero complaints" as the quality objective.

Our special services :
"Keezeg firstly must be a trustworthy company ", Company's Founder said.
Any of inquiry will be have happy reply within 24hours.
All of products must be strictly inspection before shipping;
Support After sales customer feedback quality issue investigate and implement correct action.
Professional manufacturing and professional Dog Rope Toy design;
Strive to supply the best quality products but with good price.

All Prices,minimum quantity are negotiable.

Dog Rope Toy

Dog Rope Toy

Dog Rope Toy,Rope Ball Dog Toy,Puppy Rope Toy,Long Dog Rope Toy

Ningbo Movepeak Pet Supplies Co.,LTD. , https://www.petsupplies-factory.com