Tipping Paper Technical Solution: Dropped Net, No Inking, Insufficient Print Durability

Tipping Paper Technical Solution: Dropped Net, No Inking, Insufficient Print Durability

As soon as the problem of Tipping Paper dropping off the net, no ink, and insufficient print durability" appeared, many customers first suspected CTP. Some customers even asked: "What is the print durability of your equipment during the research phase of purchasing equipment?" ? "

This is a maddening question. It is extremely simple to explain, and as a CTP user, it is necessary to understand the "mystery".

Let's first understand the exposure mechanism of the plate. Take a Huaguang plate that we are all familiar with as an example: Huaguang UV-P plate, suitable for UV-CTP positive plate. The positive image type is a photodecomposable plate. The photosensitive layer is partially decomposed by light and removed during development to form a non-graphic area (hydrophilic area), while the unexposed area is the printing image area (ink area). Thermal plates are similar. The positive type is suitable for commercial printing. Huaguang UV-N type plate, suitable for UV-CTP negative type plate, the negative type is photopolymerization/photocrosslinking type plate, the photosensitive layer is partially photopolymerized/photocrosslinked to form the printing graphic area. , while the unexposed areas are removed during development, the non-graphic areas. The negative type is suitable for packaging printing.

Let’s use the vernacular to explain the above professional terms, positive plate (UV or thermal), the part hit by the laser is washed away and coated to expose the aluminum base, which corresponds to the fountain solution on the printing machine; the part that the laser does not touch , the coating remains on the plate and corresponds to the ink on the printing press. Let’s make it clear, the part that the laser has not touched at all is not inked or dropped. How much does this have to do with CTP?

Insufficient print durability, dropped printing plates, bad images, and lack of inking are mostly caused by a combination of factors. In fact, it is not difficult to find the problem. There are many incorrect production habits and errors in the production process that can lead to the above problems.

(1) Plate processor: Excessive flushing is the most common cause. The plate processor is not the "adjustment link" in the production process. Some customers see the bottom ash on the layout and adjust the bottom ash with the concentration, temperature and speed of the liquid. In order to improve production efficiency

Just increase the temperature of the processor and speed up the washing speed; in order to save costs, we will work hard on the liquid medicine; in order to save money, we will save running water and avoid using protective glue, etc. Some printing machines are not properly maintained, crystallization, excessive brush pressure, etc., will also cause excessive flushing.

(2) Washing a variety of plates with one kind of potion, there are differences in the alkali resistance parameters of different plates, which will inevitably lead to excessive flushing.

(3) Different plates use the same calibration curve and the same focal length file output.

(4) In terms of printing machines: the pH value of the fountain solution is too large, the physical wear of the printing plate is too large (blanket, backing, pressure, speed, paper), the cleaning paste is not used correctly, and the alcohol is too large (involving the plate alcohol resistance of the material).

(5) The alkali resistance of the plate can be known by a simple washing test. Take a plate and put it directly into the plate processor for 2 to 3 times. If it becomes a white plate, you have to be careful.

(6) Tips: try a different brand of plate material; pay attention to see if the problem is always a fixed printing factory or printing machine.

(7) If your company has high requirements on printing durability or lack of machine time, and attaches great importance to quality and quality, it is recommended to use a good plate processor, relatively stable plate material, matching liquid medicine, and check the fountain solution of the printing machine. PH value, baked version. These suggestions plus each version of the baked version seem harsh and redundant, hehe, you will know when you do it and do it.